Clinical Focus

  • Diagnostic Radiology

Academic Appointments

  • Professor Emeritus, Radiology

Administrative Appointments

  • Assistant Professor of Radiology, University of California, SOM (1979 - 1982)
  • Associate Professor of Radiology;Chief of Section-CT Body Scanning & GI Radiology, University of California, SOM (1982 - 1984)
  • Professor of Radiology, Chief, Department of Radiology, San Francisco General Hospital (1984 - 1989)
  • Vice-Chairman, Department of Radiology, University of California, SOM (1984 - 1989)
  • Chief of Medical Staff, San Francisco General Hospital (1987 - 1988)
  • Professor and Chairman, Department of Radiology, University of Pittsburgh Medical Center (1989 - 1992)
  • Director, Abdominal Imaging, Department of Radiology, University of Pittsburgh Medical Center (1992 - 2008)
  • Chief, Quality Process and Improvement, Department of Radiology, University of Pittsburgh Medical Center (2008 - 2008)
  • Professor and Associate Chair for Education, Department of Radiology, Stanford University Medical Center (2008 - Present)

Honors & Awards

  • Blue Ribbon Award-Best Scientific Lecture/Exhibit, American Urological Association, Boston, Massachusetts (1981)
  • Cum Laude Award-Radiologic-Pathologic Correlation in Liver Cirrhosis, (Society of Computed Body Tomography) (1993)
  • Magna cum laude award Spectrum of imaging findings in hepatic cirrhosis, Radiological Society of North America (1993)
  • Presidential Service Award, Pittsburgh Roentgen Society (1995)
  • Certificate of Merit Citation, RSNA (1999)
  • Editor's Recognition Award with Distinction, Radiology (1996 – 2000)
  • Editor's Certificate of Recognition, Radiographics (2000)
  • Michael P. Federle Mentorship Award (First Recipient), University of Pittsburgh School of Medicine (2207)
  • Teaching Division of the Year, Department of Radiology, University of Pittsburgh School of Medicine (2008)
  • Walter B. Cannon Medal, The Society of Gastrointestinal Radiologists (2010)

Professional Education

  • Fellowship:Univ of California San Francisco (1979) CA
  • Medical Education:Georgetown University (1974) DC
  • Residency:University of Cincinnati (1978) OH
  • Board Certification: Diagnostic Radiology, American Board of Radiology (1978)
  • Internship:University of Cincinnati (1975) OH
  • N/A, Harvard University, Program for Chiefs, Clin. Svcs. (1989)
  • Clinical Instructor, UCSF School of Medicine, CT Body/Scanning/GI (1979)
  • Resident, U of Cincinnati Hosp., Radiology (1978)
  • Intern, U of Cincinnati Hosp., Internal Medicine (1975)
  • MD, Georgetown University, Medicine (1974)


2018-19 Courses


All Publications

  • Hepatocellular Carcinoma and Intrahepatic Cholangiocarcinoma: Imaging for Diagnosis, Tumor Response to Treatment and Liver Response to Radiation. Seminars in radiation oncology Lo, E. C., N Rucker, A., Federle, M. P. 2018; 28 (4): 267–76


    Hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) comprise the majority of primary liver cancers. Both HCC and ICC have characteristic imaging appearances on multiphase computed tomography (CT) and magnetic resonance imaging (MRI). Several locoregional therapies, including radiation therapy, are used to treat unresectable disease and residual or recurrent tumor. The tumor response following locoregional therapies has variable imaging manifestations. Focal liver reaction, the imaging changes of the liver following radiation treatment, should be recognized and not mistaken for tumor. We review the diagnostic imaging of HCC and ICC, imaging of tumor response to treatment, and imaging of the liver response to radiation.

    View details for DOI 10.1016/j.semradonc.2018.06.010

    View details for PubMedID 30309637

  • Contrast media for fluoroscopic examinations of the GI and GU tracts: current challenges and recommendations ABDOMINAL RADIOLOGY Federle, M. P., Jaffe, T. A., Davis, P. L., Al-Hawary, M. M., Levine, M. S. 2017; 42 (1): 90-100


    One of the significant challenges facing radiologists who perform and interpret studies of the gastrointestinal and genitourinary systems have been periodic interruptions in the availability of barium and iodinated contrast media specially formulated for gastrointestinal (GI) and genitourinary (GU) studies. These interruptions are due to the US Food and Drug Administration's recent requirement for more stringent documentation of the safety and efficacy of contrast media and the consolidation among contrast manufacturers. Therefore, radiologists may be required to recommend an alternative means of evaluation, such as computed tomography, magnetic resonance, or endoscopy, or they may need to substitute a different formulation of a contrast agent not specifically developed for GI or GU use, for example the utilization of an agent designed and marketed for vascular use. This article reviews the current status of fluoroscopic contrast media, and provides suggestions and recommendations for the optimal and alternative use of contrast media formulations.

    View details for DOI 10.1007/s00261-016-0861-1

    View details for Web of Science ID 000392291700009

    View details for PubMedID 27503380

  • Aortoenteric fistulas: spectrum of CT findings ABDOMINAL IMAGING Raman, S. P., Kamaya, A., Federle, M., Fishman, E. K. 2013; 38 (2): 367-375


    This article reviews the causes of aortoenteric fistulas, diagnostic options, and important CT findings.Aortoenteric fistula, a rare but potentially fatal entity, presents a significant challenge to radiologists in diagnosis, largely because of its subtle and nonspecific imaging findings. These fistulas can be divided into primary and secondary forms, depending on the presence or absence of prior aortic reconstructive surgery, but the secondary form is more common. Typical CT findings, which can overlap with those seen in perigraft infection, aortitis, infected/mycotic aneurysms, perianeurysmal fibrosis, and the immediate post-operative period after placement of a graft, include: Effacement of the fat planes around the aorta, perigraft fluid/soft tissue thickening, ectopic gas, tethering of adjacent thickened bowel loops towards the aortic graft, and in rare cases, extravasation of contrast from the aorta into the involved segment of bowel.

    View details for DOI 10.1007/s00261-012-9873-7

    View details for Web of Science ID 000316144100019

    View details for PubMedID 22366854

  • Imaging Manifestations of Abdominal Fat Necrosis and Its Mimics RADIOGRAPHICS Kamaya, A., Federle, M. P., Desser, T. S. 2011; 31 (7): 2021-2034


    Intraabdominal fat is a metabolically active tissue that may undergo necrosis through a number of mechanisms. Fat necrosis is a common finding at abdominal cross-sectional imaging, and it may cause abdominal pain, mimic findings of acute abdomen, or be asymptomatic and accompany other pathophysiologic processes. Common processes that are present in fat necrosis include torsion of an epiploic appendage, infarction of the greater omentum, and fat necrosis related to trauma or pancreatitis. In addition, other pathologic processes that involve fat may be visualized at computed tomography, including focal lipohypertrophy, pathologic fat paucity (lipodystrophies), and malignancies such as liposarcoma, which may mimic benign causes of fat stranding. Because fat necrosis and malignant processes such as liposarcoma and peritoneal carcinomatosis may mimic one another, knowledge of a patient's clinical history and prior imaging studies is essential for accurate diagnosis.

    View details for DOI 10.1148/rg.317115046

    View details for Web of Science ID 000297047000019

    View details for PubMedID 22084185

  • Septic Thrombophlebitis of the Portal Venous System: Clinical and Imaging Findings in Thirty-Three Patients DIGESTIVE DISEASES AND SCIENCES Ames, J. T., Federle, M. P. 2011; 56 (7): 2179-2184


    Our purpose was to review the clinical and imaging findings in a series of patients with septic thrombophlebitis of the portal venous system in order to define criteria that might allow more confident and timely diagnosis.This is a retrospective case series. The clinical and imaging features were analyzed in 33 subjects with septic thrombophlebitis of the portal venous system.All 33 patients with septic thrombophlebitis of the portal venous system had pre-disposing infectious or inflammatory processes. Contrast-enhanced CT studies of patients with septic thrombophlebitis typically demonstrate an infectious gastrointestinal source (82%), thrombosis (70%), and/or gas (21%) of the portal system or its branches, and intrahepatic abnormalities such as a transient hepatic attenuation difference (THAD) (42%) or abscess (61%).Septic thrombophlebitis of the portal system is often associated with an infectious source in the gastrointestinal tract and sepsis. Contrast-enhanced CT demonstrates an infectious gastrointestinal source, thrombosis or gas within the portal system or its branches, and intrahepatic abnormalities such as abscess in most cases. We report a THAD in several of our patients, an observation that was not made in prior reports of septic thrombophlebitis.

    View details for DOI 10.1007/s10620-010-1533-6

    View details for Web of Science ID 000291481800038

    View details for PubMedID 21221797

  • Chemoembolization for Unresectable HepatoCellular Carcinoma in Patients with or without Portal Vein Thrombosis HEPATO-GASTROENTEROLOGY Carr, B. I., Irish, W., Federle, M. P. 2010; 58 (104): 1375-1381
  • Managing Incidental Findings on Abdominal CT: White Paper of the ACR Incidental Findings Committee JOURNAL OF THE AMERICAN COLLEGE OF RADIOLOGY Berland, L. L., Silverman, S. G., Gore, R. M., Mayo-Smith, W. W., Megibow, A. J., Yee, J., Brink, J. A., Baker, M. E., Federle, M. P., Foley, W. D., Francis, I. R., Herts, B. R., Israel, G. M., Krinsky, G., Platt, J. F., Shuman, W. P., Taylor, A. J. 2010; 7 (10): 754-773
  • Xanthogranulomatous cholecystitis: Diagnostic performance of CT to differentiate from gallbladder cancer EUROPEAN JOURNAL OF RADIOLOGY Goshima, S., Chang, S., Wang, J. H., Kanematsu, M., Bae, K. T., Federle, M. P. 2010; 74 (3): E80-E84
  • Distinguishing clinical and imaging features of nodular regenerative hyperplasia and large regenerative nodules of the liver CLINICAL RADIOLOGY Ames, J. T., Federle, M. P., Chopra, K. 2009; 64 (12): 1190-1195


    Nodular regenerative hyperplasia (NRH) and large regenerative nodules (LRN) are distinct types of hepatocellular nodules that have been confused in the radiology literature. However, distinction is critical because their clinical significance is quite different. Our purpose was to review the clinical and imaging findings in a series of patients with NRH and LRN in order to identify distinguishing clinical and imaging features.This was a retrospective case series. The clinical and imaging features were compared in 36 patients with pathological proof of NRH and 23 patients with pathological evidence of LRN.NRH and LRN have different predisposing factors and imaging findings. NRH is often associated with organ transplantation, myeloproliferative disease, or autoimmune processes. Livers with NRH typically do not have enhancing nodules; none of the present patients with NRH had enhancing liver masses. In contrast, LRN are often associated with Budd-Chiari syndrome. Enhancing liver masses were noted in 19 (83%) of the 23 patients with LRN. The p values for the comparisons were less than 0.001 for both enhancing liver masses and hepatic vein thrombosis.NRH and LRN can have distinct clinical presentations and imaging appearances. LRN often result in enhancing liver nodules, whereas NRH usually does not. Clinical and imaging information enables the distinction of LRN and NRH in many cases.

    View details for DOI 10.1016/j.crad.2009.07.015

    View details for Web of Science ID 000273305900007

    View details for PubMedID 19913129

  • Liver Lesions With Hepatic Capsular Retraction SEMINARS IN ULTRASOUND CT AND MRI Blachar, A., Federle, M. P., Sosna, J. 2009; 30 (5): 426-435


    Retraction of the liver capsule may be associated with a diverse spectrum of benign and malignant etiologies. The more common causes include focal confluent fibrosis in cirrhotic livers, cholangiocarcinoma, and treated liver tumors, such as hepatocellular carcinoma, metastases, and lymphoma. Less common etiologies include primary sclerosing cholangitis, epithelioid hemangioendothelioma, hepatic hemangioma, solitary fibrous tumor of the liver, and hepatic inflammatory pseudotumor. Hepatic capsular retraction may also result from iatrogenic and noniatrogenic trauma. Due to the diversity and different nature of the various etiologies associated with this sign, it is important that radiologists be familiar with the characteristic features of these abnormalities, to avoid misdiagnosis that may adversely affect the therapeutic approach. It is also important to know that, contrary to some reports, hepatic capsular retraction is not a sign of malignant disease. The purpose of this article is to familiarize readers with the spectrum of benign and malignant etiologies of this sign and to point out additional computed tomographic findings that may allow confident diagnosis of the specific hepatic lesion responsible for the capsular retraction. The hepatic capsular and subcapsular regions may be affected by focal or diffuse pathologies affecting the liver. This hepatic area is more prone to be involved in various malignant and benign diseases due to several factors: the negative subdiaphragmatic pressure that may draw infected material and malignant cells toward the diaphragm, the perihepatic ligaments connecting the liver capsule with adjacent viscera, forming a direct root of dissemination, and the systemic blood inflow that supplies this region in addition to the portal and hepatic arterial blood flow. This is the reason for the multiple pathologic conditions and pseudolesions that occur at the hepatic capsular and subcapsular regions.

    View details for DOI 10.1053/j.sult.2009.06.002

    View details for Web of Science ID 000270442900006

    View details for PubMedID 19842567

  • Spontaneous Abdominal Hemorrhage: Causes, CT Findings, and Clinical Implications AMERICAN JOURNAL OF ROENTGENOLOGY Furlan, A., Fakhran, S., Federle, M. P. 2009; 193 (4): 1077-1087


    The purpose of this article is to present the most common causes of spontaneous abdominal hemorrhage and to review the CT findings that are important in establishing the correct diagnosis and in guiding appropriate therapy.Knowledge of the common CT manifestations of various causes of spontaneous abdominal hemorrhage allows their accurate diagnosis and has a direct impact on clinical decision making.

    View details for DOI 10.2214/AJR.08.2231

    View details for Web of Science ID 000270033300023

    View details for PubMedID 19770332

  • Imaging Approach for Evaluation of Focal Liver Lesions CLINICAL GASTROENTEROLOGY AND HEPATOLOGY Marin, D., Furlan, A., Federle, M. P., Midiri, M., Brancatelli, G. 2009; 7 (6): 624-634


    Focal liver lesions are common in the general population. Radiology (imaging) plays a pivotal role for the diagnosis, staging, treatment planning, and follow-up of focal liver lesions. To maximize lesion detection and characterization, imaging needs to be performed with appropriate equipment by using protocols carefully designed on the basis of the underlying clinical context. In addition, the decision of an imaging modality cannot be based on the diagnostic accuracy of an imaging test solely but must also consider patient safety and cost-effectiveness.

    View details for DOI 10.1016/j.cgh.2009.03.024

    View details for Web of Science ID 000267189400006

    View details for PubMedID 19348962

  • CT Hypotension Complex (Shock Bowel) Is Not Always Due to Traumatic Hypovolemic Shock AMERICAN JOURNAL OF ROENTGENOLOGY Ames, J. T., Federle, M. P. 2009; 192 (5): W230-W235


    The purpose of our study was to review the clinical and CT findings in a substantial series of 41 patients with the shock bowel sign to determine if there is an association between shock bowel (and other CT signs of hypotension) and conditions other than post-traumatic hypovolemic shock.The shock bowel sign and the CT hypotension complex are frequently associated with hypotension from causes other than trauma-induced hypovolemic shock, such as severe head or spine injury, cardiac arrest, septic shock, bacterial endocarditis, and diabetic ketoacidosis. Other elements of the CT hypotension complex such as flattening of the inferior vena cava and aorta, abnormal pancreatic enhancement and peripancreatic fluid, and hypoperfusion of the spleen and liver are variably associated with shock bowel whether due to posttraumatic hypovolemia or other causes of hypotension. The CT hypotension complex (shock bowel) has important prognostic and therapeutic implications and can probably be distinguished from bowel trauma and other forms of bowel injury in most cases.

    View details for DOI 10.2214/AJR.08.1474

    View details for Web of Science ID 000265387300049

    View details for PubMedID 19380528

  • Focal Confluent Fibrosis in Cirrhotic Liver: Natural History Studied with Serial CT AMERICAN JOURNAL OF ROENTGENOLOGY Brancatelli, G., Baron, R. L., Federle, M. P., Sparacia, G., Pealer, K. 2009; 192 (5): 1341-1347


    The objective of this study was to assess the long-term natural history of focal confluent fibrosis in cirrhotic liver with CT.Two radiologists retrospectively reviewed in consensus 118 liver CT examinations in 26 patients (19 men, seven women; age range, 32-68 years; mean age, 50 years) performed over approximately 6 years. Helical CT scans were obtained before and 30-35 and 65-70 seconds after injection of 125-150 mL of contrast medium at a rate of 4-5 mL/s. Proof of cirrhosis was based on liver transplantation (n = 6), biopsy (n = 9), or imaging findings (n = 11). The number, location, and attenuation of fibrotic lesions and presence of trapped vessels were evaluated. Variation of hepatic retraction associated with the development of focal confluent fibrosis lesions was assessed using the ellipsoid volume formula and an arbitrary retraction index.Each radiologist identified 41 focal confluent fibrosis lesions. All lesions were identified by both radiologists. Twelve patients (46%) had a single lesion, 13 (50%) had two lesions, and one (4%) had three lesions. Thirty-four (83%) of 41 lesions were located in segment IV, VII, or VIII. Thirty-two lesions (78%) were hypoattenuating on unenhanced images, 25 lesions (61%) were hypoattenuating on hepatic arterial phase images, and 20 lesions (49%) were isoattenuating on portal venous phase images. Seven lesions (17%) were or became hyperattenuating at follow-up on portal venous phase images. Trapped vessels were found in six lesions (15%). The retraction index showed a significant increase over time (r = 0.423, p < or = 0.0001).The degree of capsule retraction associated with focal confluent fibrosis evolves with time and relates to the natural evolution of cirrhosis.

    View details for DOI 10.2214/AJR.07.2782

    View details for Web of Science ID 000265387300028

    View details for PubMedID 19380559

  • Using contrast-enhanced helical CT to visualize arterial extravasation after blunt abdominal trauma: Incidence and organ distribution AMERICAN JOURNAL OF ROENTGENOLOGY Yao, D. C., Jeffrey, R. B., MIRVIS, S. E., Weekes, A., Pederle, M. P., Kim, C., Lane, M. J., Prabhakar, P., Ralls, P. W. 2002; 178 (1): 17-20


    We evaluated the incidence and organ distribution of arterial extravasation identified using contrast-enhanced helical CT in patients who had sustained abdominal visceral injuries and pelvic fractures after blunt trauma.Five hundred sixty-five consecutive patients from four level I trauma centers who had CT scans showing abdominal visceral injuries or pelvic fractures were included in this series. The presence or absence of arterial extravasation, as well as the anatomic sites of arterial extravasation, was noted. We obtained clinical follow-up data, including surgical or angiographic findings.In our series, 104 (18.4%) of 565 patients had arterial extravasation. Of the 104 patients, 81 (77.9%) underwent surgery, embolization, or both. The combined rate of surgery or embolization in patients with arterial extravasation was statistically higher than expected at all four institutions (p <0.001). The spleen was the most common organ injured, occurring in 277 (49.0%) of 565 patients, and arterial extravasation occurred in 49 (17.7%) of 277 patients with splenic injury. Several other visceral injuries were associated with arterial extravasation, including hepatic, renal, adrenal, and mesenteric injuries.Based on the limited reports of arterial extravasation in the nonhelical CT literature, the percentage (18%) of clinically stable patients in our study with CT scans showing arterial extravasation was higher than anticipated. This finding likely reflects the improved diagnostic capability of helical CT. Although the spleen and liver were the organs most commonly associated with arterial extravasation, radiologists should be aware that arterial extravasation may be associated with several other visceral injuries.

    View details for Web of Science ID 000172927900003

    View details for PubMedID 11756079