Bio

Clinical Focus


  • Gastroenterology
  • Endoscopy

Academic Appointments


Professional Education


  • Medical Education:UCSD School of Medicine (1996) CA
  • Fellowship:Stanford University School of Medicine (2002) CA
  • Residency:Stanford University School of Medicine (1999) CA
  • Internship:Stanford University School of Medicine (1997) CA
  • Board Certification: Gastroenterology, American Board of Internal Medicine (2002)
  • Board Certification: Internal Medicine, American Board of Internal Medicine (1999)

Research & Scholarship

Current Research and Scholarly Interests


1. Gastrointestinal Endoscopy- Techniques and Outcomes
2. Development of new endoscopic devices
3. Diagnosis of intestinal ischemia
4. High risk endoscopic resection

Clinical Trials


  • Advanced Gastrointestinal Endoscopic Imaging Not Recruiting

    To develop new methods to detect malignant and premalignant conditions of the gastrointestinal tract.

    Stanford is currently not accepting patients for this trial. For more information, please contact Chirstopher Contag, (650) 725 - 8781.

    View full details

Teaching

2013-14 Courses


Publications

Journal Articles


  • Treatment of nonampullary sporadic duodenal adenomas with endoscopic mucosal resection or ablation. Digestive diseases and sciences Perumpail, R., Friedland, S. 2013; 58 (10): 2751-2752

    View details for DOI 10.1007/s10620-013-2787-6

    View details for PubMedID 23884756

  • Metabolomic-derived novel cyst fluid biomarkers for pancreatic cysts: glucose and kynurenine GASTROINTESTINAL ENDOSCOPY Park, W. G., Wu, M., Bowen, R., Zheng, M., Fitch, W. L., Pai, R. K., Wodziak, D., Visser, B. C., Poultsides, G. A., Norton, J. A., Banerjee, S., Chen, A. M., Friedland, S., Scott, B. A., Pasricha, P. J., Lowe, A. W., Peltz, G. 2013; 78 (2): 295-?

    Abstract

    BACKGROUND: Better pancreatic cyst fluid biomarkers are needed. OBJECTIVE: To determine whether metabolomic profiling of pancreatic cyst fluid would yield clinically useful cyst fluid biomarkers. DESIGN: Retrospective study. SETTING: Tertiary-care referral center. PATIENTS: Two independent cohorts of patients (n = 26 and n = 19) with histologically defined pancreatic cysts. INTERVENTION: Exploratory analysis for differentially expressed metabolites between (1) nonmucinous and mucinous cysts and (2) malignant and premalignant cysts was performed in the first cohort. With the second cohort, a validation analysis of promising identified metabolites was performed. MAIN OUTCOME MEASUREMENTS: Identification of differentially expressed metabolites between clinically relevant cyst categories and their diagnostic performance (receiver operating characteristic [ROC] curve). RESULTS: Two metabolites had diagnostic significance-glucose and kynurenine. Metabolomic abundances for both were significantly lower in mucinous cysts compared with nonmucinous cysts in both cohorts (glucose first cohort P = .002, validation P = .006; and kynurenine first cohort P = .002, validation P = .002). The ROC curve for glucose was 0.92 (95% confidence interval [CI], 0.81-1.00) and 0.88 (95% CI, 0.72-1.00) in the first and validation cohorts, respectively. The ROC for kynurenine was 0.94 (95% CI, 0.81-1.00) and 0.92 (95% CI, 0.76-1.00) in the first and validation cohorts, respectively. Neither could differentiate premalignant from malignant cysts. Glucose and kynurenine levels were significantly elevated for serous cystadenomas in both cohorts. LIMITATIONS: Small sample sizes. CONCLUSION: Metabolomic profiling identified glucose and kynurenine to have potential clinical utility for differentiating mucinous from nonmucinous pancreatic cysts. These markers also may diagnose serous cystadenomas.

    View details for DOI 10.1016/j.gie.2013.02.037

    View details for Web of Science ID 000321825200015

    View details for PubMedID 23566642

  • A Raman-based endoscopic strategy for multiplexed molecular imaging. Proceedings of the National Academy of Sciences of the United States of America Zavaleta, C. L., Garai, E., Liu, J. T., Sensarn, S., Mandella, M. J., Van de Sompel, D., Friedland, S., Van Dam, J., Contag, C. H., Gambhir, S. S. 2013; 110 (25): E2288-97

    Abstract

    Endoscopic imaging is an invaluable diagnostic tool allowing minimally invasive access to tissues deep within the body. It has played a key role in screening colon cancer and is credited with preventing deaths through the detection and removal of precancerous polyps. However, conventional white-light endoscopy offers physicians structural information without the biochemical information that would be advantageous for early detection and is essential for molecular typing. To address this unmet need, we have developed a unique accessory, noncontact, fiber optic-based Raman spectroscopy device that has the potential to provide real-time, multiplexed functional information during routine endoscopy. This device is ideally suited for detection of functionalized surface-enhanced Raman scattering (SERS) nanoparticles as molecular imaging contrast agents. This device was designed for insertion through a clinical endoscope and has the potential to detect and quantify the presence of a multiplexed panel of tumor-targeting SERS nanoparticles. Characterization of the Raman instrument was performed with SERS particles on excised human tissue samples, and it has shown unsurpassed sensitivity and multiplexing capabilities, detecting 326-fM concentrations of SERS nanoparticles and unmixing 10 variations of colocalized SERS nanoparticles. Another unique feature of our noncontact Raman endoscope is that it has been designed for efficient use over a wide range of working distances from 1 to 10 mm. This is necessary to accommodate for imperfect centering during endoscopy and the nonuniform surface topology of human tissue. Using this endoscope as a key part of a multiplexed detection approach could allow endoscopists to distinguish between normal and precancerous tissues rapidly and to identify flat lesions that are otherwise missed.

    View details for DOI 10.1073/pnas.1211309110

    View details for PubMedID 23703909

  • Endoscopic management of nonlifting colon polyps. Diagnostic and therapeutic endoscopy Friedland, S., Shelton, A., Kothari, S., Kochar, R., Chen, A., Banerjee, S. 2013; 2013: 412936-?

    Abstract

    Background and Study Aims. The nonlifting polyp sign of invasive colon cancer is considered highly sensitive and specific for cancer extending beyond the mid-submucosa. However, prior interventions can cause adenomas to become nonlifting due to fibrosis. It is unclear whether nonlifting adenomas can be successfully treated endoscopically. The aim of this study was to evaluate outcomes in a referral practice incorporating a standardized protocol of attempted endoscopic resection of nonlifting lesions previously treated by biopsy, polypectomy, surgery, or tattoo placement. Patients and Methods. Retrospective review of patients undergoing colonoscopy by one endoscopist at two hospitals found to have nonlifting lesions from prior interventions. Lesions with biopsy proven invasive cancer or definite endoscopic features of invasive cancer were excluded. Lesions ? 8?mm were routinely injected with saline prior to attempted endoscopic resection. Polypectomy was performed using a stiff snare, followed by argon plasma coagulation (APC) if necessary. Results. 26 patients each had a single nonlifting lesion with a history of prior intervention. Endoscopic resection was completed in 25 (96%). 22 required snare resection and APC. 1 patient had invasive cancer and was referred for surgery. The recurrence rate on follow-up colonoscopy was 26%. All of the recurrences were successfully treated endoscopically. There was 1 postprocedure bleed (4%), no perforations, and no other complications. Conclusions. The majority of adenomas that are nonlifting after prior interventions can be treated successfully and safely by a combination of piecemeal polypectomy and ablation. Although recurrence rates are high at 26%, these too can be successfully treated endoscopically.

    View details for DOI 10.1155/2013/412936

    View details for PubMedID 23761952

  • Endoscopic mucosal resection with an over-the-counter hyaluronate preparation GASTROINTESTINAL ENDOSCOPY Friedland, S., Kothari, S., Chen, A., Park, W., Banerjee, S. 2012; 75 (5): 1040-1044

    Abstract

    Hyaluronic acid (HA) provides a long-lasting and distinct mucosal elevation for EMR, but expense and inconvenience have limited its adoption.To evaluate the safety and efficacy of an over-the-counter 0.15% HA preparation for EMR.Retrospective study.Veterans Administration Hospital and university hospital.30 patients with a total of 32 colonic lesions and 1 duodenal lesion.EMR by using HA.En bloc resection rate and complications.EMR was successful in all cases. En bloc resection was achieved in 26 of the 28 lesions up to 25 mm in diameter. Two lesions, both with fibrosis from prior attempted resection, had trace residual tissue necessitating cauterization with argon plasma. Five lesions measuring 30 mm to 60 mm all required piecemeal resection. There was one complication, a postpolypectomy bleed.Small number of patients and retrospective design.EMR may be performed safely and effectively by using an inexpensive, over-the-counter 0.15% HA preparation. Further studies are needed to verify the results of this study and to compare the safety and efficacy of this HA preparation with saline solution.

    View details for DOI 10.1016/j.gie.2012.01.010

    View details for Web of Science ID 000303277400016

    View details for PubMedID 22381528

  • A tandem colonoscopy study of adenoma miss rates during endoscopic training: a venture into uncharted territory GASTROINTESTINAL ENDOSCOPY Munroe, C. A., Lee, P., Copland, A., Wu, K. K., Kaltenbach, T., Soetikno, R. M., Friedland, S. 2012; 75 (3): 561-567

    Abstract

    Tandem colonoscopy is regarded as the reference standard for the evaluation of the adenoma detection rate (ADR) and adenoma miss rate (AMR) during colonoscopy. Pooled results from previous tandem studies yield AMRs of 22%. The AMR of trainees is important to estimate the number of colonoscopies required to develop competence in screening for colorectal neoplasms.To measure the ADR and AMR of trainees as a function of experience.Prospective tandem colonoscopy study at an academic VA medical center. A trainee initially attempted colonoscopy. If the trainee was able to intubate the cecum, the trainee performed the withdrawal, and the colonoscopy was then repeated by the attending physician to assess the AMR.Twelve trainee endoscopists were included in the study. Trainees had between 0 and 33 months of previous endoscopic experience and had done between 0 and 605 previous colonoscopies. A total of 230 patients were evaluated for the study, and 218 patients were enrolled. Complete tandem colonoscopy was performed in 147 patients. There was a 54% ADR. The mean (standard deviation) size of the adenomas in the cohort was 5.9 (5.3) mm. Significant variables in multivariate logistic regression analysis for missed adenomas were trainee experience (P = .011) and patient age (P < .001). The AMR decreased with increasing experience, and it is estimated that 450 colonoscopies are required to attain AMRs of less than 25% in a 60-year-old patient.Single-center study; the attending physician performing the second pass was not blinded to the first pass. The AMR was only analyzed for cases in which the trainee was able to reach the cecum with no or minimal assistance.Our tandem colonoscopy study demonstrates that the AMR decreases as the experience of trainees increases and is a late competency attained during training. Future training may need to incorporate these findings to serve as a basis for determining appropriate training guidelines.

    View details for DOI 10.1016/j.gie.2011.11.037

    View details for Web of Science ID 000301319900017

    View details for PubMedID 22341103

  • Proficiency in the Diagnosis of Nonpolypoid Colorectal Neoplasm Yields High Adenoma Detection Rates DIGESTIVE DISEASES AND SCIENCES Kaltenbach, T., Mcgill, S. K., Kalidindi, V., Friedland, S., Soetikno, R. 2012; 57 (3): 764-770

    Abstract

    Current efforts to prevent colorectal cancer focus on the detection and removal of neoplasms. Nonpolypoid colorectal neoplasms (NP-CRN) have a subtle appearance that can be difficult to recognize during colonoscopy. Endoscopists must first be familiar with the patterns of NP-CRN in order to detect and diagnose them. We studied the adenoma detection rates of endoscopists who had trained to detect NP-CRN, versus endoscopists who had not.Design: Retrospective Nested Case Control Study. Setting: Outpatient Screening Colonoscopy. Participants: Adult Veterans. Intervention: Proficiency in the features and diagnosis of NP-CRN. Main Outcomes Measurements: Adenoma detection.In total, 462 patients had screening colonoscopies-267 by colonoscopists who had trained in the features and diagnosis of NP-CRN. Patient characteristics were similar between groups-the majority were men with a mean age of 62 ± 6 years. Neoplasia was more prevalent (45.7 vs. 34.9%; p = 0.02) in patients evaluated by the trained compared to the conventionally trained group. Trained colonoscopists had a higher adenoma detection rate (0.76 vs. 0.54 adenomas per patient, p < 0.001); removed a higher proportion of neoplasia (77 vs. 35%, p < 0.001); and more frequently diagnosed NP-CRN lesions (OR 2.98, 95% CI: 1.46-6.08) compared to colonoscopists without supplemental training.Endoscopists who are proficient in the detection of NP-CRN had significantly higher adenoma detection rates-of both polypoid and flat adenomas-compared to endoscopists without training, and were more specific in resection of adenomatous over hyperplastic lesions.

    View details for DOI 10.1007/s10620-011-1921-6

    View details for Web of Science ID 000300578200024

    View details for PubMedID 21964768

  • In vivo near-infrared dual-axis confocal microendoscopy in the human lower gastrointestinal tract JOURNAL OF BIOMEDICAL OPTICS Piyawattanametha, W., Ra, H., Qiu, Z., Friedland, S., Liu, J. T., Loewke, K., Kino, G. S., Solgaard, O., Wang, T. D., Mandella, M. J., Contag, C. H. 2012; 17 (2)

    Abstract

    Near-infrared confocal microendoscopy is a promising technique for deep in vivo imaging of tissues and can generate high-resolution cross-sectional images at the micron-scale. We demonstrate the use of a dual-axis confocal (DAC) near-infrared fluorescence microendoscope with a 5.5-mm outer diameter for obtaining clinical images of human colorectal mucosa. High-speed two-dimensional en face scanning was achieved through a microelectromechanical systems (MEMS) scanner while a micromotor was used for adjusting the axial focus. In vivo images of human patients are collected at 5 frames/sec with a field of view of 362×212 ?m(2) and a maximum imaging depth of 140 ?m. During routine endoscopy, indocyanine green (ICG) was topically applied a nonspecific optical contrasting agent to regions of the human colon. The DAC microendoscope was then used to obtain microanatomic images of the mucosa by detecting near-infrared fluorescence from ICG. These results suggest that DAC microendoscopy may have utility for visualizing the anatomical and, perhaps, functional changes associated with colorectal pathology for the early detection of colorectal cancer.

    View details for DOI 10.1117/1.JBO.17.2.021102

    View details for Web of Science ID 000303033600004

    View details for PubMedID 22463020

  • Colonoscopy With Clipping Is Useful in the Diagnosis and Treatment of Diverticular Bleeding CLINICAL GASTROENTEROLOGY AND HEPATOLOGY Kaltenbach, T., Watson, R., Shah, J., Friedland, S., Sato, T., Shergill, A., McQuaid, K., Soetikno, R. 2012; 10 (2): 131-137

    Abstract

    Diverticular bleeding is the most common cause of acute severe lower gastrointestinal bleeding (LGIB) in Western countries. Diagnostic and therapeutic approaches, including endoscopy, radiology, or surgery, have not been standardized. We investigated colonoscopy as a first-line modality to diagnose and manage patients with LGIB.We performed a retrospective study of data collected from 2 tertiary Veterans hospitals of 64 patients (61 men, 76 ± 11 years) with acute severe diverticular bleeding, based on colonoscopy examination. We assessed primary hemostasis using endoscopic clipping for diverticular bleeding and described the bleeding stigmata. We measured early (<30 days) and late rebleeding, blood transfusion requirements, hospital stay and complications.Patients received 3.1 ± 3.0 and 0.9 ± 2.2 U of blood before and after colonoscopy, respectively. Twenty-four of the 64 patients (38%) had diverticular stigmata of recent hemorrhage; and 21 of these patients (88%) were treated successfully using endoscopic clips, without complication or early rebleeding. Hospital stays averaged 6.4 ± 5.6 days. Endoscopic clipping provided primary hemostasis in 9/12 patients (75%) with active diverticular bleeding. During 35 ± 18 months of follow-up, late recurrent diverticular bleeding occurred in 22% of the patients (14/64) after a mean time period of 22 months; 5 of the patients (21%) with stigmata of recent hemorrhage who received clip treatment had rebleeding at 43 months. Rebleeding was self-limited in 8 patients (57%), was clipped in 4 (29%), or was embolized in 2 (14%).Colonoscopy can be a safe first-line diagnostic and therapeutic approach for patients with severe LGIB. Endoscopic clipping provides hemostasis of active diverticular bleeding. Recurrent bleeding occurs in about 21% of patients who were treated with clips, at approximately 4 years; most bleeding is self-limited or can be retreated by endoscopic clipping.

    View details for DOI 10.1016/j.cgh.2011.10.029

    View details for Web of Science ID 000299789800015

    View details for PubMedID 22056302

  • Is colonoscopy best learned underwater? Journal of interventional gastroenterology Friedland, S., Perumpail, R. 2012; 2 (3): 140-141

    View details for PubMedID 23805396

  • A novel device for ablation of abnormal esophageal mucosa GASTROINTESTINAL ENDOSCOPY Friedland, S., Triadafilopoulos, G. 2011; 74 (1): 182-188

    Abstract

    Current ablation devices for Barrett's esophagus are effective but have significant limitations.To evaluate a new ablation device.Laboratory and animal model evaluation of the CryoBalloon, a compliant balloon that is simultaneously inflated and cooled by liquid nitrous oxide delivered by using a small, disposable, handheld unit.Cryoablation of esophageal mucosa was performed in 11 swine. Multiple ablations were created in each animal at various ablation times.Animals were euthanized at 4 days (n = 6) or 28 days (n = 5), and histological assessments were performed. At 4 days, the percentage of esophageal mucosa successfully ablated was measured. At 28 days, the circumference of the esophagus at the center of the ablation zone was measured to assess for stricture formation.The CryoBalloon was simple to operate, and balloon contact with tissue was easily maintained. As the ablation time was increased from 6 to 12 seconds, the percentage of mucosa ablated increased from below 60% to above 90%. Maximal effect on the mucosa was reached at 12 seconds. Ablation of up to 14 seconds resulted in minimal luminal narrowing. As the ablation duration increased from 14 to 22 seconds, there was progressive stricture formation evident at 28 days. All of the animals tolerated the treatments without difficulty and, regardless of ablation duration, were able to continue oral intake and gain weight after the procedure.Ablation of normal porcine squamous mucosa may differ from that of human Barrett's esophagus.The CryoBalloon device enables circumferential mucosal ablation in a 1-step process by using a novel, through-the-scope balloon. The maximal effect on the mucosa is achieved with a 12-second application time. Because of its ease of use, this new device merits further study so that we can find its possible role in the treatment of Barrett's esophagus.

    View details for DOI 10.1016/j.gie.2011.03.1119

    View details for Web of Science ID 000292429400027

    View details for PubMedID 21531411

  • Use of the Colonoscope Training Model with the Colonoscope 3D Imaging Probe Improved Trainee Colonoscopy Performance: A Pilot Study DIGESTIVE DISEASES AND SCIENCES Kaltenbach, T., Leung, C., Wu, K., Yan, K., Friedland, S., Soetikno, R. 2011; 56 (5): 1496-1502

    Abstract

    Colonoscopy insertion is difficult to teach due to the inability of current training models to provide realistic tactile sensation with simultaneous three-dimensional (3D) colonoscope display.To assess the influence of a simulator consisting of a colon model coupled with 3D instrument visualization on trainee colonoscopy performance.Pilot study using the simulator model with three trainees who were not proficient in colonoscopy. At random times over a 6-week period, trainees participated in an individualized half-day session using the Colonoscope Training Model and a colonoscope equipped with a 3D magnetic probe imaging system (ScopeGuide) in six standardized cases. A blinded supervising instructor graded patient-based colonoscopy performance over the 6-week period, and we independently analyzed the 2-week period before and after the intervention. We also measured cecal intubation and withdrawal times and medication requirements.Trainees performed 86 patient-based colonoscopies. Following the intervention, the colonoscopy performance score improved from 4.4 ± 2.3 to 5.9 ± 2.4 (p = 0.005). Trainees had a 76% cecal intubation rate following the session as compared to 43% before training (p = 0.004), while utilizing less time, 14 ± 7 versus 18 ± 11 min (p = 0.056) and less medication (p > 0.05).Colonoscopy simulation using the Colonoscope Training Model and the ScopeGuide produced an immediate and large effect on trainee colonoscopy performance.

    View details for DOI 10.1007/s10620-011-1614-1

    View details for Web of Science ID 000289899200033

    View details for PubMedID 21409379

  • Learning and teaching the water method (with videos). Journal of interventional gastroenterology Friedland, S., Leung, F. W. 2011; 1 (3): 127-129

    Abstract

    The water method is an insertion technique for colonoscopy which has recently become popular owing to its demonstrated ability to decrease patient pain and sedation requirements. This review focuses on learning and teaching the water method. Data from the United States and Asia suggests that trainees at all levels of experience can safely learn and utilize the water method. Demonstrated benefits in some of the reviewed studies include lessened sedation requirements, less pain for patients and increased cecal intubation rates in minimally sedated patients. These benefits are realized without compromising safety, adenoma detection rates, or procedure times.

    View details for PubMedID 22163083

  • The water immersion technique for colonoscopy insertion. Gastroenterology & hepatology Friedland, S. 2010; 6 (9): 555-556

    View details for PubMedID 21088743

  • Integrating urgent multidetector CT scanning in the diagnostic algorithm of active lower GI bleeding GASTROINTESTINAL ENDOSCOPY Copland, A., Munroe, C. A., Friedland, S., Triadafilopoulos, G. 2010; 72 (2): 402-405

    View details for DOI 10.1016/j.gie.2010.04.014

    View details for Web of Science ID 000280778800027

    View details for PubMedID 20674629

  • Water immersion versus standard colonoscopy insertion technique: randomized trial shows promise for minimal sedation ENDOSCOPY Leung, C. W., Kaltenbach, T., Soetikno, R., Wu, K. K., Leung, F. W., Friedland, S. 2010; 42 (7): 557-563

    Abstract

    Water immersion is an alternative colonoscopy technique that may reduce discomfort and facilitate insertion of the instrument. This was a prospective study to compare the success of colonoscopy with minimal sedation using water immersion and conventional air insufflation.A total of 229 patients were randomized to either water immersion or the standard air insertion technique. The primary outcome was success of minimal sedation colonoscopy, which was defined as reaching the cecum without additional sedation, exchange of the adult colonoscope or hands-on assistance for trainees. Patient comfort and satisfaction were also assessed.Successful minimal-sedation colonoscopy was achieved in 51 % of the water immersion group compared with 28 % in the standard air group (OR, 2.66; 95 % CI 1.48 - 4.79; P = 0.0004). Attending physicians had 79 % success with water immersion compared with 47 % with air insufflation (OR, 4.19; 95 % CI 1.5 - 12.17; P = 0.002), whereas trainees had 34 % success with water compared with 16 % using air (OR, 2.75; 95 % CI 1.15 - 6.86; P = 0.01). Using the water method, endoscopists intubated the cecum faster and this was particularly notable for trainees (13.0 +/- 7.5 minutes with water vs. 20.5 +/- 13.9 minutes with air; P = 0.0001). Total procedure time was significantly shorter with water for both experienced and trainee endoscopists ( P < 0.05). Patients reported less intraprocedural pain with water compared with air (4.1 +/- 2.7 vs. 5.3 +/- 2.7; P = 0.001), with a similar level of satisfaction. There was no difference in the neoplasm detection rates between the groups.Colonoscopy insertion using water immersion increases the success rate of minimal sedation colonoscopy. Use of the technique leads to a decrease in discomfort, time to reach the cecum, and the amount of sedative and analgesic used, without compromising patient satisfaction.

    View details for DOI 10.1055/s-0029-1244231

    View details for Web of Science ID 000279406900006

    View details for PubMedID 20593332

  • Long-Term Impact of Capsule Endoscopy in Patients Referred for Iron-Deficiency Anemia DIGESTIVE DISEASES AND SCIENCES Sheibani, S., Levesque, B. G., Friedland, S., Roost, J., Gerson, L. B. 2010; 55 (3): 703-708

    Abstract

    Video capsule endoscopy (VCE) is recommended as the third diagnostic test for patients with iron-deficiency anemia (IDA) after a normal upper endoscopy and colonoscopy.To study long-term outcomes after VCE in patients with IDA.We performed a retrospective study of VCE studies performed at Stanford University Hospital or the VA Palo Alto Health Care System from 2002 to 2006. We assessed endoscopic or radiographic procedures performed post-CE and contacted patients by telephone in order to determine current medical status and potential resolution of anemia since the VCE.We invited 153 patients to participate, and 82 (54%) patients agreed to enroll including 57 patients with IDA and 25 patients with overt gastrointestinal bleeding. The overt group received more transfusions pre-CE (P < 0.05). The mean follow-up time was 36 +/- 16 months (median 33 months, range 14-67) in the IDA referral group and 40 +/- 16 months (median 39 months, range 17-69) in the overt bleeding group (P = 0.3). Positive findings on VCE were detected in 35 (60%) and 15 (60%) patients in the IDA referral and overt groups, respectively (P= 1.0). Of the 35 patients in the IDA referral group with significant VCE findings, 15 underwent therapeutic procedures, while 20 were managed conservatively. Over the mean follow-up period, 23% of the IDA referral group and 22% of the overt group remained anemic (P = 0.30).Most patients referred for VCE examination to evaluate IDA were no longer anemic at 36 months of follow-up, with or without therapeutic intervention.

    View details for DOI 10.1007/s10620-009-1046-3

    View details for Web of Science ID 000274617500019

    View details for PubMedID 19941072

  • Meckel's Diverticulum with Gastrointestinal Bleeding: Role of Computed Tomography in Diagnosis DIGESTIVE DISEASES AND SCIENCES Munroe, C. A., Copland, A., Pai, R., Friedland, S., Triadafilopoulos, G. 2010; 55 (2): 242-244

    View details for DOI 10.1007/s10620-009-1029-4

    View details for Web of Science ID 000273520900005

    View details for PubMedID 19888654

  • Use of an endoscope-compatible probe to detect colonic dysplasia with Fourier transform infrared spectroscopy JOURNAL OF BIOMEDICAL OPTICS Mackanos, M. A., Hargrove, J., Wolters, R., Du, C. B., Friedland, S., Soetikno, R. M., Contag, C. H., Arroyo, M. R., Crawford, J. M., Wang, T. D. 2009; 14 (4)

    Abstract

    Fourier transform infrared (FTIR) spectroscopy is sensitive to the molecular composition of tissue and has the potential to identify premalignant tissue (dysplasia) as an adjunct to endoscopy. We demonstrate collection of mid-infrared absorption spectra with a silver halide (AgCl(0.4)Br(0.6)) optical fiber and use spectral preprocessing to identify optimal subranges that classify colonic mucosa as normal, hyperplasia, or dysplasia. We collected spectra (n=83) in the 950 to 1800 cm(-1) regime on biopsy specimens obtained from human subjects (n=37). Subtle differences in the magnitude of the absorbance peaks at specific wave numbers were observed. The best double binary algorithm for distinguishing normal-versus-dysplasia and hyperplasia-versus-dysplasia was determined from an exhaustive search of spectral intervals and preprocessing techniques. Partial least squares discriminant analysis was used to classify the spectra using a leave-one-subject-out cross-validation strategy. The results were compared with histology reviewed independently by two gastrointestinal pathologists. The optimal thresholds identified resulted in an overall sensitivity, specificity, accuracy, and positive predictive value of 96%, 92%, 93%, and 82%, respectively. These results indicated that mid-infrared absorption spectra collected remotely with an optical fiber can be used to identify colonic dysplasia with high accuracy, suggesting that continued development of this technique for the early detection of cancer is promising.

    View details for DOI 10.1117/1.3174387

    View details for Web of Science ID 000270540100013

    View details for PubMedID 19725718

  • Endoscopic necrosectomy of organized pancreatic necrosis: a currently practiced NOTES procedure JOURNAL OF HEPATO-BILIARY-PANCREATIC SURGERY Friedland, S., Kaltenbach, T., Sugimoto, M., Soetikno, R. 2009; 16 (3): 266-269

    Abstract

    Endoscopic necrosectomy is now an established minimally invasive method for treatment of organized pancreatic necrosis.Review of methods and results of endoscopic treatment of pancreatic necrosis.Reports by multiple groups have demonstrated favorable results of endoscopic necrosectomy. The mortality of critically ill patients undergoing endoscopic treatment in several series is approximately 10%. Some patients will eventually also require surgery for situations such as complete pancreatic duct disruption, but even in these cases endoscopic necrosectomy is useful because pancreatic surgery can often be delayed until the patient is stable.Endoscopic necrosectomy will likely assume an increasing role in the treatment of pancreatic necrosis. This should result in reduced morbidity and mortality in these critically ill patients.

    View details for DOI 10.1007/s00534-009-0088-4

    View details for Web of Science ID 000265566800005

    View details for PubMedID 19350193

  • Colonoscopic polypectomy in anticoagulated patients WORLD JOURNAL OF GASTROENTEROLOGY Friedland, S., Sedehi, D., Soetikno, R. 2009; 15 (16): 1973-1976

    Abstract

    To review our experience performing polypectomy in anticoagulated patients without interruption of anticoagulation.Retrospective chart review at the Veterans Affairs Palo Alto Health Care System. Two hundred and twenty five polypectomies were performed in 123 patients. Patients followed a standardized protocol that included stopping warfarin for 36 h to avoid supratherapeutic anticoagulation from the bowel preparation. Patients with lesions larger than 1 cm were generally rescheduled for polypectomy off warfarin. Endoscopic clips were routinely applied prophylactically.One patient (0.8%, 95% CI: 0.1%-4.5%) developed major post-polypectomy bleeding that required transfusion. Two others (1.6%, 95% CI: 0.5%-5.7%) had self-limited hematochezia at home and did not seek medical attention. The average polyp size was 5.1 +/- 2.2 mm.Polypectomy can be performed in therapeutically anticoagulated patients with lesions up to 1 cm in size with an acceptable bleeding rate.

    View details for DOI 10.3748/wjg.15.1973

    View details for Web of Science ID 000265619800008

    View details for PubMedID 19399929

  • Safe endoscopic treatment of large colonic lipomas using endoscopic looping technique DIGESTIVE AND LIVER DISEASE Kaltenbach, T., Milkes, D., Friedland, S., Soetikno, R. 2008; 40 (12): 958-961

    Abstract

    Colonic lipomas are benign, submucosal tumours that are usually asymptomatic. Typically, they are incidentally diagnosed during colonoscopy. Due to a low prevalence, the natural history of lipomas remains largely unknown. While large (>2 cm) lesions can cause symptoms and complications, their endoscopic treatment is not routinely recommended because of prior reports of a high rate of perforation.We used a standardized technique of polypectomy, using endoscopic looping to resect large colonic lipomas in 8 patients and followed their clinical outcomes.The mean lipoma size was 3.8+/-1.2 cm (range 2.5-6 cm). No patient developed bleeding or perforation. On follow-up (mean=13.5 months, range 2-29), there was one small residual lesion.Colonic lipomas larger than 2 cm can be safely and efficaciously removed using endoloop assisted polypectomy technique.

    View details for DOI 10.1016/j.dld.2008.03.010

    View details for Web of Science ID 000261804600008

    View details for PubMedID 18434264

  • A randomised tandem colonoscopy trial of narrow band imaging versus white light examination to compare neoplasia miss rates GUT Kaltenbach, T., Friedland, S., Soetikno, R. 2008; 57 (10): 1406-1412

    Abstract

    Colonoscopy, the "gold standard" screening test for colorectal cancer (CRC), has known diagnostic limitations. Advances in endoscope technology have focused on improving mucosal visualisation. In addition to increased angle of view and resolution features, recent colonoscopes have non-white-light optics, such as narrow band imaging (NBI), to enhance image contrast. We aimed to study the neoplasia diagnostic characteristics of NBI, by comparing the neoplasm miss rate when the colonoscopy was performed under NBI versus white light (WL).Randomised controlled trial.US Veterans hospital.Elective colonoscopy adults.We randomly assigned patients to undergo a colonoscopic examination using NBI or WL. All patients underwent a second examination using WL, as the reference standard.The primary end point was the difference in the neoplasm miss rate, and secondary outcome was the neoplasm detection rate.In 276 tandem colonoscopy patients, there was no significant difference of miss or detection rates between NBI or WL colonoscopy techniques. Of the 135 patients in the NBI group, 17 patients (12.6%; 95% confidence interval (CI) 7.5 to 19.4%) had a missed neoplasm, as compared with 17 of the 141 patients (12.1%; 95% CI 7.2 to 18.6%) in the WL group, with a miss rate risk difference of 0.5% (95% CI -7.2 to 8.3). 130 patients (47%) had at least one neoplasm. Missed lesions with NBI showed similar characteristics to those missed with WL. All missed neoplasms were tubular adenomas, the majority (78%) was < or = 5 mm and none were larger than 1 cm (one-sided 95% CI up to 1%). Nonpolypoid lesions represented 35% (13/37) of missed neoplasms.NBI did not improve the colorectal neoplasm miss rate compared to WL; the miss rate for advanced adenomas was less than 1% and for all adenomas was 12%. The neoplasm detection rates were similar high using NBI or WL; almost a half the study patients had at least one adenoma. Clinicaltrials.gov identifier: NCT00628147.

    View details for DOI 10.1136/gut.2007.137984

    View details for Web of Science ID 000259198800017

    View details for PubMedID 18523025

  • Integrated gastrointestinal imaging and therapy GASTROENTEROLOGY Soetikno, R., Kaltenbach, T., Binmoeller, K., Friedland, S., Burdon, T. 2008; 134 (5): 1290-1292

    View details for DOI 10.1053/j.gastro.2008.03.047

    View details for Web of Science ID 000255676700008

    View details for PubMedID 18471503

  • Detection of colonic dysplasia in vivo using a targeted heptapeptide and confocal microendoscopy NATURE MEDICINE Hsiung, P., Hardy, J., Friedland, S., Soetikno, R., Du, C. B., Wu, A. P., Sahbaie, P., Crawford, J. M., Lowe, A. W., Contag, C. H., Wang, T. D. 2008; 14 (4): 454-458

    Abstract

    A combination of targeted probes and new imaging technologies provides a powerful set of tools with the potential to improve the early detection of cancer. To develop a probe for detecting colon cancer, we screened phage display peptide libraries against fresh human colonic adenomas for high-affinity ligands with preferential binding to premalignant tissue. We identified a specific heptapeptide sequence, VRPMPLQ, which we synthesized, conjugated with fluorescein and tested in patients undergoing colonoscopy. We imaged topically administered peptide using a fluorescence confocal microendoscope delivered through the instrument channel of a standard colonoscope. In vivo images were acquired at 12 frames per second with 50-microm working distance and 2.5-microm (transverse) and 20-microm (axial) resolution. The fluorescein-conjugated peptide bound more strongly to dysplastic colonocytes than to adjacent normal cells with 81% sensitivity and 82% specificity. This methodology represents a promising diagnostic imaging approach for the early detection of colorectal cancer and potentially of other epithelial malignancies.

    View details for DOI 10.1038/nm1692

    View details for Web of Science ID 000254674100034

    View details for PubMedID 18345013

  • American gastroenterological association (AGA) institute technology assessment on image-enhanced endoscopy GASTROENTEROLOGY Kaltenbach, T., Sano, Y., Friedland, S., Soetikno, R. 2008; 134 (1): 327-340

    Abstract

    This document presents the official recommendations of the American Gastroenterological Association (AGA) Institute Technology Assessment on "Image-Enhanced Endoscopy." It was approved by the Clinical Practice and Economics Committee on August 3, 2007, and by the AGA Institute Governing Board September 27, 2007.

    View details for DOI 10.1053/j.gastro.2007.10.062

    View details for Web of Science ID 000252066400037

    View details for PubMedID 18061178

  • Small caliber overtube-assisted colonoscopy WORLD JOURNAL OF GASTROENTEROLOGY Friedland, S., Soetikno, R. M. 2007; 13 (44): 5933-5937

    Abstract

    To combine the benefits of a new thin flexible scope with elimination of excessive looping through the use of an overtube.Three separate retrospective series. Series 1: 25 consecutive male patients undergoing unsedated colonoscopy using the new device at a Veteran's hospital in the United States. Series 2: 75 male patients undergoing routine colonoscopy using an adult colonoscope, pediatric colonoscope, or the new device. Series 3: 35 patients who had incomplete colonoscopies using standard instruments.Complete colonoscopy was achieved in all 25 patients in the unsedated series with a median cecal intubation time of 6 min and a median maximal pain score of 3 on a 0-10 scale. In the 75 routine cases, there was significantly less pain with the thin scope compared to standard adult and pediatric colonoscopes. Of the 35 patients in the previously incomplete colonoscopy series, 33 were completed with the new system.Small caliber overtube-assisted colonoscopy is less painful than colonoscopy with standard adult and pediatric colonoscopes. Male patients could undergo unsedated colonoscopy with the new system with relatively little pain. The new device is also useful for most patients in whom colonoscopy cannot be completed with standard instruments.

    View details for Web of Science ID 000250799800015

    View details for PubMedID 17990359

  • Functional imaging of colonic mucosa with a fibered Confocal microscope for real-time in vivo pathology CLINICAL GASTROENTEROLOGY AND HEPATOLOGY Wang, T. D., Friedland, S., Sahbaie, P., Soetikno, R., Hsiung, P., Liu, J. T., Crawford, J. M., Contag, C. H. 2007; 5 (11): 1300-1305

    Abstract

    Histologic interpretation of disease currently is performed with static images of excised tissues, and is limited by processing artifact, sampling error, and interpretive variability. The aim of this study was to show the use of functional optical imaging of viable mucosa for quantitative evaluation of colonic neoplasia in real time.Fluorescein (5 mg/mL) was administered topically in 54 human subjects undergoing screening colonoscopy. Fluorescence images were collected with 488-nm excitation at 12 frames/s with the confocal microendoscopy system. Movement of fluorescein in the transient period (<5 s) and the lamina propria:crypt contrast ratio in the steady-state phase (>5 s) were quantified.Normal mucosa showed circular crypts with uniform size, hyperplasia revealed proliferative glands with serrated lumens, and adenomas displayed distorted elongated glands. For t less than 5 seconds, fluorescein passed through normal epithelium with a peak speed of 1.14 +/- 0.09 microm/s at t = 0.5 seconds, and accumulated into lamina propria as points of fluorescence that moved through the interglandular space with an average speed of 41.7 +/- 3.4 microm/s. Passage of fluorescein through adenomatous mucosa was delayed substantially. For t greater than 5 seconds, high sensitivity, specificity, and accuracy was achieved using a discriminant function to evaluate the contrast ratio to distinguish normal from lesional mucosa (91%, 87%, and 89%, respectively; P < .001), hyperplasia from adenoma (97%, 96%, and 96%, respectively; P < .001), and tubular from villous adenoma (100%, 92%, and 93%, respectively; P < .001).Confocal imaging can be performed in vivo to assess the functional behavior of tissue in real time for providing pathologic interpretation, representing a new method for histologic evaluation.

    View details for DOI 10.1016/j.cgh.2007.07.013

    View details for Web of Science ID 000250944900012

    View details for PubMedID 17936692

  • Detection of endogenous biomolecules in Barrett's esophagus by Fourier transform infrared spectroscopy PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Wang, T. D., Triadafilopoulos, G., Crawford, J. M., Dixon, L. R., Bhandari, T., Sahbaie, P., Friediand, S., Soetikno, R., Contag, C. H. 2007; 104 (40): 15864-15869

    Abstract

    Fourier transform infrared (FTIR) spectroscopy provides a unique molecular fingerprint of tissue from endogenous sources of light absorption; however, specific molecular components of the overall FTIR signature of precancer have not been characterized. In attenuated total reflectance mode, infrared light penetrates only a few microns of the tissue surface, and the influence of water on the spectra can be minimized, allowing for the analyses of the molecular composition of tissues. Here, spectra were collected from 98 excised specimens of the distal esophagus, including 38 squamous, 38 intestinal metaplasia (Barrett's), and 22 gastric, obtained endoscopically from 32 patients. We show that DNA, protein, glycogen, and glycoprotein comprise the principal sources of infrared absorption in the 950- to 1,800-cm(-1) regime. The concentrations of these biomolecules can be quantified by using a partial least-squares fit and used to classify disease states with high sensitivity, specificity, and accuracy. Moreover, use of FTIR to detect premalignant (dysplastic) mucosa results in a sensitivity, specificity, positive predictive value, and total accuracy of 92%, 80%, 92%, and 89%, respectively, and leads to a better interobserver agreement between two gastrointestinal pathologists for dysplasia (kappa = 0.72) versus histology alone (kappa = 0.52). Here, we demonstrate that the concentration of specific biomolecules can be determined from the FTIR spectra collected in attenuated total reflectance mode and can be used for predicting the underlying histopathology, which will contribute to the early detection and rapid staging of many diseases.

    View details for DOI 10.1073/pnas.0707567104

    View details for Web of Science ID 000249942700049

    View details for PubMedID 17901200

  • Short- and long-term outcomes of standardized EMR of nonpolypoid (flat and depressed) colorectal lesions >= 1 cm (with video) GASTROINTESTINAL ENDOSCOPY Kaltenbach, T., Friedland, S., Maheshwari, A., Ouyang, D., Rouse, R. V., Wren, S., Soetikno, R. 2007; 65 (6): 857-865

    Abstract

    Nonpolypoid (flat and depressed) colorectal lesions are increasingly recognized. Their endoscopic removal requires specialized EMR techniques, which are more complex to perform. Outcomes data on EMR of nonpolypoid neoplasms in the United States is needed.To determine the safety and efficacy of EMR in the resection of nonpolypoid colorectal neoplasms > or = 1 cm.Retrospective analysis.Veterans Affairs Palo Alto Health Care System.Over a 5-year period, patients who underwent EMR for nonpolypoid colorectal lesions > or = 1 cm.A standardized approach that included lesion assessment, classification, inject-and-cut EMR technique, reassessment, and treatment of residual tissue.Complete resection, bleeding, perforation, development of advanced cancer, and death.A total of 100 patients (125 lesions: 117 flat and 8 depressed) met inclusion criteria. Mean size was 16.7 +/- 7 mm (range, 10-50 mm). Histology included 5 submucosal invasive cancers, 5 carcinomas in situ, and 91 adenomas. Thirty-eight patients (48 lesions) did not receive surveillance colonoscopy: 8 had surgery, 16 had hyperplastic pathology, and 14 did not undergo repeat examination. Surveillance colonoscopy was performed on 62 patients (77 lesions). Complete resection was achieved in 100% of these patients after 1 to 3 surveillance colonoscopies. All patients received follow-up (mean [standard deviation] = 4.5 +/- 1.4 years); none developed colorectal cancer or metastasis.Single endoscopist, retrospective study.A standardized EMR (inject-and-cut) technique is a safe and curative treatment option in nonpolypoid colorectal neoplasms (> or = 1 cm) in the United States.

    View details for DOI 10.1016/j.gie.2006.11.035

    View details for Web of Science ID 000246217300017

    View details for PubMedID 17466205

  • Use of a double balloon enteroscope facilitates caecal intubation after incomplete colonoscopy with a standard colonoscope DIGESTIVE AND LIVER DISEASE Kaltenbach, T., Soetikno, R., Friedland, S. 2006; 38 (12): 921-925

    Abstract

    Caecal intubation is a necessary step in the complete endoscopic evaluation of the colon. Studies have estimated that experienced colonoscopists may fail to reach the caecum in up to 10% of cases.To evaluate the utility of the double balloon enteroscope used for complete examination of the colon in patients with incomplete standard colonoscopy.Twenty consecutive patients with incomplete colonoscopies within the Veterans Affairs Palo Alto Health Care System. Mean age of 66 years (S.D.+/-12 years, range 46-84), 16 men.Prospective single-centre case series on the caecal intubation rate using standard double balloon enteroscope technique in patients with previous incomplete conventional colonoscopy.Use of the standard double balloon enteroscope technique permitted complete colonoscopy to be achieved in 95% of the patients (19/20). Seven patients (35%) had significant pathology beyond the extent of the prior incomplete colonoscopy. We performed endoscopic mucosal resection, polypectomy or biopsy. The mean time to reach the caecum was 28 min (S.D.+/-20 min, range 6-90 min). The sedation was similar to conventional colonoscopy. No complications occurred.The double balloon enteroscope technology and technique can be used to complete examination of the colon in patients who were referred because of incomplete standard colonoscopy.

    View details for DOI 10.1016/j.dld.2006.08.003

    View details for Web of Science ID 000243715600010

    View details for PubMedID 16990055

  • Dual-axes confocal reflectance microscope for distinguishing colonic neoplasia JOURNAL OF BIOMEDICAL OPTICS Liu, J. T., Mandella, M. J., Friedland, S., Soetikno, R., Crawford, J. M., Contag, C. H., Kino, G. S., Wang, T. D. 2006; 11 (5)

    Abstract

    A dual-axes confocal reflectance microscope has been developed that utilizes a narrowband laser at 1310 nm to achieve high axial resolution, image contrast, field of view, and tissue penetration for distinguishing among normal, hyperplastic, and dysplastic colonic mucosa ex vivo. Light is collected off-axis using a low numerical aperture objective to obtain vertical image sections, with 4- to 5-microm resolution, at tissue depths up to 610 microm. Post-objective scanning enables a large field of view (610 x 640 microm), and balanced-heterodyne detection provides sensitivity to collect vertical sections at one frame per second. System optics are optimized to effectively reject out-of-focus scattered light without use of a low-coherence gate. This design is scalable to millimeter dimensions, and the results demonstrate the potential for a miniature instrument to detect precancerous tissues, and hence to perform in vivo histopathology.

    View details for DOI 10.1117/1.2363363

    View details for Web of Science ID 000242576900023

    View details for PubMedID 17092168

  • Colonoscopy with polypectomy in anticoagulated patients GASTROINTESTINAL ENDOSCOPY Friedland, S., Soetikno, R. 2006; 64 (1): 98-100

    Abstract

    According to current practice guidelines for performance of colonoscopy in patients requiring long-term anticoagulation, polypectomy is considered a high-risk procedure for which anticoagulation must temporarily be discontinued. However, these guidelines are based on expert opinion, and the bleeding risk after polypectomy in anticoagulated patients is not known.Measure the risk of postpolypectomy bleeding in patients who undergo colonoscopic polypectomy while anticoagulated.Retrospective review of patients who underwent polypectomy without discontinuation of anticoagulation.Veterans Administration Palo Alto Health Care System.Forty-one polypectomies were performed in 21 patients. All patients had been receiving long-term anticoagulation with warfarin; the average international normalized ratio was 2.3 (range 1.4-4.9; normal 0.9-1.2). To prevent supratherapeutic anticoagulation, warfarin was withheld for 36 hours before the procedure while the patients were on a liquid diet. The average polyp size was 5 mm (range 3-10 mm).All patients underwent polypectomy followed immediately by prophylactic application of one or two clips to prevent bleeding.Rate of postpolypectomy bleeding.There were no episodes of postpolypectomy bleeding. The 95% CI for the risk of bleeding was 0% to 8.6% when analyzed per polypectomy and 0% to 15% when analyzed per patient.Small single-center retrospective study.Our experience suggests that small polyps can be removed with a very low risk of bleeding when clips are applied immediately after polypectomy. If these results can be confirmed in a larger multicenter study, our protocol may become an alternative to withholding anticoagulation in patients at high risk of thrombosis.

    View details for DOI 10.1016/j.gie.2006.02.030

    View details for Web of Science ID 000238766600019

    View details for PubMedID 16813811

  • Absence of ischemia in telangiectasias of chronic radiation proctopathy ENDOSCOPY Friedland, S., Benaron, D., Maxim, P., Parachikov, I., Soetikno, R. 2006; 38 (5): 488-492

    Abstract

    It has been postulated that chronic radiation proctopathy, clinically manifested by hematochezia and by the appearance of multiple telangiectasias, is caused by ischemia. This theory is based on reports that appeared in the 1980s which described obliterative endarteritis in patients with chronic radiation-induced ulcers. However, bleeding from radiation proctopathy is typically successfully treated endoscopically by widespread tissue coagulation, and the complications that would be expected to occur if the tissue was ischemic, such as poor wound healing, generally do not arise. We therefore hypothesized that the ischemia theory is incorrect and that rectal capillary oxygen saturation is normal in patients with telangiectasias of chronic radiation proctopathy.We developed a visible-light spectroscopy device that measures mucosal capillary hemoglobin oxygen saturation during endoscopy (having reported its operating characteristics previously). We prospectively studied 20 patients who had typical findings of multiple rectal telangiectasias, 1 - 20 years after undergoing external-beam irradiation for prostate or rectal carcinoma. We measured and compared the mucosal capillary oxygen saturations in the affected areas of the distal rectum and in endoscopically normal areas in the rectosigmoid colon.Mucosal oxygenation was normal in all 20 patients in affected areas (64 % - 80 %) and in unaffected areas (63 % - 75 %). The mean mucosal hemoglobin oxygen saturation was actually slightly higher in the affected areas of the rectum than in the uninvolved rectosigmoid colon (73 % vs. 69 %, P < 0.01).The common form of chronic radiation proctopathy, characterized by multiple telangiectasias without ulcers or strictures, is not associated with ongoing mucosal ischemia. This finding may explain why endoscopic treatment of this disorder, in which large areas of the mucosa are coagulated with argon plasma or other treatment modalities that cause widespread ulceration, does not typically result in complications from poor wound healing.

    View details for DOI 10.1055/s-2005-921175

    View details for Web of Science ID 000237922000009

    View details for PubMedID 16767584

  • Clipping for upper gastrointestinal bleeding AMERICAN JOURNAL OF GASTROENTEROLOGY Kaltenbach, T., Friedland, S., Barro, J., Soetikno, R. 2006; 101 (5): 915-918
  • Nonpolypoid (flat and depressed) colorectal neoplasms GASTROENTEROLOGY Soetikno, R., Friedland, S., Kaltenbach, T., Chayama, K., Tanaka, S. 2006; 130 (2): 566-576

    View details for DOI 10.1053/j.gastro.2005.12.006

    View details for Web of Science ID 000235525700029

    View details for PubMedID 16472608

  • Design of a visible-light spectroscopy clinical tissue oximeter JOURNAL OF BIOMEDICAL OPTICS Benaron, D. A., Parachikov, I. H., Cheong, W. F., Friedland, S., Rubinsky, B. E., Otten, D. M., Liu, F. W., Levinson, C. J., Murphy, A. L., Price, J. W., Talmi, Y., Weersing, J. P., Duckworth, J. L., Horchner, U. B., Kermit, E. L. 2005; 10 (4)

    Abstract

    We develop a clinical visible-light spectroscopy (VLS) tissue oximeter. Unlike currently approved near-infrared spectroscopy (NIRS) or pulse oximetry (SpO2%), VLS relies on locally absorbed, shallow-penetrating visible light (475 to 625 nm) for the monitoring of microvascular hemoglobin oxygen saturation (StO2%), allowing incorporation into therapeutic catheters and probes. A range of probes is developed, including noncontact wands, invasive catheters, and penetrating needles with injection ports. Data are collected from: 1. probes, standards, and reference solutions to optimize each component; 2. ex vivo hemoglobin solutions analyzed for StO2% and pO2 during deoxygenation; and 3. human subject skin and mucosal tissue surfaces. Results show that differential VLS allows extraction of features and minimization of scattering effects, in vitro VLS oximetry reproduces the expected sigmoid hemoglobin binding curve, and in vivo VLS spectroscopy of human tissue allows for real-time monitoring (e.g., gastrointestinal mucosal saturation 69+/-4%, n=804; gastrointestinal tumor saturation 45+/-23%, n=14; and p<0.0001), with reproducible values and small standard deviations (SDs) in normal tissues. FDA approved VLS systems began shipping earlier this year. We conclude that VLS is suitable for the real-time collection of spectroscopic and oximetric data from human tissues, and that a VLS oximeter has application to the monitoring of localized subsurface hemoglobin oxygen saturation in the microvascular tissue spaces of human subjects.

    View details for DOI 10.1117/1.1979504

    View details for Web of Science ID 000232799200015

    View details for PubMedID 16178639

  • Optical detection of tumors in vivo by visible light tissue oximetry TECHNOLOGY IN CANCER RESEARCH & TREATMENT Maxim, P. G., Carson, J. J., Benaron, D. A., Loo, B. W., Xing, L., Boyer, A. L., Friedland, S. 2005; 4 (3): 227-234

    Abstract

    Endoscopy is a standard procedure for identifying tumors in patients suspected of having gastrointestinal (G.I.) cancer. The early detection of G.I. neoplasms during endoscopy is currently made by a subjective visual inspection that relies to a high degree on the experience of the examiner. This process can be difficult and unreliable, as tumor lesions may be visually indistinguishable from benign inflammatory conditions and the surrounding mucosa. In this study, we evaluated the ability of local ischemia detection using visible light spectroscopy (VLS) to differentiate neoplastic from normal tissue based on capillary tissue oxygenation during endoscopy. Real-time data were collected (i) from human subjects (N = 34) monitored at various sites during endoscopy (enteric mucosa, malignant, and abnormal tissue such as polyps) and (ii) murine animal subjects with human tumor xenografts. Tissue oximetry in human subjects during endoscopy revealed a tissue oxygenation (StO2%, mean +/- SD) of 46 +/- 22% in tumors, which was significantly lower than for normal mucosal oxygenation (72 +/- 4%; P < or = 0.0001). No difference in tissue oxygenation was observed between normal and non-tumor abnormal tissues (P = N.S.). Similarly, VLS tissue oximetry for murine tumors revealed a mean local tumor oxygenation of 45% in LNCaP, 50% in M21, and 24% in SCCVII tumors, all significantly lower than normal muscle tissue (74%, P < 0.001). These results were further substantiated by positive controls, where a rapid real-time drop in tumor oxygenation was measured during local ischemia induced by clamping or epinephrine. We conclude that VLS tissue oximetry can distinguish neoplastic tissue from normal tissue with a high specificity (though a low sensitivity), potentially aiding the endoscopic detection of gastrointestinal tumors.

    View details for Web of Science ID 000229787600001

    View details for PubMedID 15896077

  • Reflectance spectrophotometry for the assessment of mucosal perfusion in the gastrointestinal tract. Gastrointestinal endoscopy clinics of North America Friedland, S., Soetikno, R., Benaron, D. 2004; 14 (3): 539-?

    Abstract

    Reflectance spectrophotometry (RS) is an optical technology that has been used for nearly three decades in the measurement of tissue hemoglobin oxygen saturation in the gastrointestinal tract. The technology has evolved substantially throughout this period,and commercial devices are now available for use in clinical trials. Numerous studies have used RS to investigate the importance of mucosal perfusion in disorders such as ulcer disease, portal hypertension, and septic shock. More recently, the technique has been applied to measure changes in perfusion in response to infusion of vasoactive medications and maneuvers such as cardiopulmonary bypass. The results of current trials investigating the application of RS in critical care monitoring and vascular interventions will likely determine whether the technique will evolve from predominantly a research tool to a clinically useful device.

    View details for PubMedID 15261201

  • Continuous, noninvasive, and localized microvascular tissue oximetry using visible light spectroscopy ANESTHESIOLOGY Benaron, D. A., Parachikov, I. H., Friedland, S., Soetikno, R., Brock-Utne, J., van der Starre, P. J., Nezhat, C., Terris, M. K., Maxim, P. G., Carson, J. J., Razavi, M. K., Gladstone, H. B., Fincher, E. F., Hsu, C. P., Clark, F. L., Cheong, W. F., Duckworth, J. L., Stevenson, D. K. 2004; 100 (6): 1469-1475

    Abstract

    The authors evaluated the ability of visible light spectroscopy (VLS) oximetry to detect hypoxemia and ischemia in human and animal subjects. Unlike near-infrared spectroscopy or pulse oximetry (SpO2), VLS tissue oximetry uses shallow-penetrating visible light to measure microvascular hemoglobin oxygen saturation (StO2) in small, thin tissue volumes.In pigs, StO2 was measured in muscle and enteric mucosa during normoxia, hypoxemia (SpO2 = 40-96%), and ischemia (occlusion, arrest). In patients, StO2 was measured in skin, muscle, and oral/enteric mucosa during normoxia, hypoxemia (SpO2 = 60-99%), and ischemia (occlusion, compression, ventricular fibrillation).In pigs, normoxic StO2 was 71 +/- 4% (mean +/- SD), without differences between sites, and decreased during hypoxemia (muscle, 11 +/- 6%; P < 0.001) and ischemia (colon, 31 +/- 11%; P < 0.001). In patients, mean normoxic StO2 ranged from 68 to 77% at different sites (733 measures, 111 subjects); for each noninvasive site except skin, variance between subjects was low (e.g., colon, 69% +/- 4%, 40 subjects; buccal, 77% +/- 3%, 21 subjects). During hypoxemia, StO2 correlated with SpO2 (animals, r2 = 0.98; humans, r2 = 0.87). During ischemia, StO2 initially decreased at -1.3 +/- 0.2%/s and decreased to zero in 3-9 min (r2 = 0.94). Ischemia was distinguished from normoxia and hypoxemia by a widened pulse/VLS saturation difference (Delta < 30% during normoxia or hypoxemia vs. Delta > 35% during ischemia).VLS oximetry provides a continuous, noninvasive, and localized measurement of the StO2, sensitive to hypoxemia, regional, and global ischemia. The reproducible and narrow StO2 normal range for oral/enteric mucosa supports use of this site as an accessible and reliable reference point for the VLS monitoring of systemic flow.

    View details for Web of Science ID 000221551300018

    View details for PubMedID 15166566

  • Gastric pancreatic rest leading to pyogenic liver abscess GASTROINTESTINAL ENDOSCOPY Friedland, S., Yu, A., Rouse, R. V., Wong, D., Nino-Murcia, M., Soetikno, R. M. 2002; 56 (3): 438-440

    View details for DOI 10.1067/mge.2002.126619

    View details for Web of Science ID 000177775800026

    View details for PubMedID 12196792

  • Bedside scoring system to predict the risk of developing pancreatitis following ERCP ENDOSCOPY Friedland, S., Soetikno, R. M., Vandervoort, J., Montes, H., Tham, T., Carr-Locke, D. L. 2002; 34 (6): 483-488

    Abstract

    Pancreatitis is the most common significant complication of endoscopic retrograde cholangiopancreatography (ERCP). The aim of the present study was to develop a simple scoring system that clinicians can use to predict the risk of post-ERCP pancreatitis.We analyzed a prospectively assembled database of 1835 ERCP procedures at a single referral hospital. Multivariate logistic regression analysis was performed to identify risk factors for pancreatitis and determine their relative contributions. From these results, a scoring system was constructed. The performance of the scoring system was assessed on the entire procedure database and in selected subgroups.Multivariate analysis yielded four risk factors: pain during the procedure, cannulation of the pancreatic duct (PD), previous post-ERCP pancreatitis, and number of cannulation attempts. Based on the regression model, the scoring system was: 4 points for pain, 3 points for PD cannulation, 2 points for a history of post-ERCP pancreatitis, and 1 - 4 points depending on the number of cannulation attempts. A total score of 1 - 4 points was associated with a low risk of pancreatitis (< 2 %), while a score of 5 - 8 points had an intermediate risk (7 %), and a score of 9 or above had a high risk (28 %).This simple scoring system may enable clinicians to stratify patients into low-risk, medium-risk, and high-risk groups for the development of post-ERCP pancreatitis. In addition, when patients with suspected sphincter of Oddi dysfunction and patients who underwent minor papilla cannulation were analyzed separately, the scoring system was able to predict accurately the pancreatitis risk of these patients as well.

    View details for Web of Science ID 000176079300011

    View details for PubMedID 12048633

  • Stenting the sigmoid colon in a terminally ill patient with prostate cancer. Journal of palliative medicine Friedland, S., Hallenbeck, J., Soetikno, R. M. 2001; 4 (2): 153-156

    Abstract

    Large bowel obstruction in the terminally ill patient can be difficult to manage. We describe a patient with sigmoid colon obstruction caused by metastatic prostate cancer in the pelvis who required hospitalization because of severe pain and obstructive symptoms. Treatment with an endoscopically placed self-expandable metal stent allowed the patient to have immediate resolution of symptoms and to receive hospice care at home.

    View details for PubMedID 11441623

  • Lift and ligate: a new technique to treat a bleeding polypectomy stump GASTROINTESTINAL ENDOSCOPY Soetikno, R. M., Friedland, S., Lewit, V., Woodford, S. 2000; 52 (5): 681-683

    View details for Web of Science ID 000165148900021

    View details for PubMedID 11060200

Stanford Medicine Resources: