Emeritus Faculty, Acad Council, Radiology
The goal was to determine discordance rates between preliminary radiology reports provided by on-call radiology house staff and final reports from attending radiologists on cross-sectional imaging studies requested by emergency department staff after hours.A triplicate carbon copy reporting form was developed to provide permanent records of preliminary radiology reports and to facilitate communication of discrepant results to the emergency department. Data were collected over 21 weeks to determine the number of discordant readings. Patients' medical records were reviewed to show whether discrepancies were significant or insignificant and to assess their impact on subsequent management and patient outcome.The emergency department requested 2830 cross-sectional imaging studies after hours and 2311 (82%) had a copy of the triplicate form stored in radiology archives. Discrepancies between the preliminary and final report were recorded in 47 (2.0%), with 37 (1.6%) considered significant: 14 patients needed no change, 13 needed a minor change, and 10 needed a major change in subsequent management. Ten (0.43%) of the discordant scans were considered insignificant. A random sample of 104 (20%) of the 519 scans without a paper triplicate form was examined. Seventy-one (68%) did have a scanned copy of the triplicate form in the electronic record, with a discrepancy recorded in 3 (4.2%), which was not statistically different from the main cohort (P = .18).Our study suggests a high level of concordance between preliminary reports from on-call radiology house staff and final reports by attending subspecialty radiologists on cross-sectional imaging studies requested by the emergency department.
View details for DOI 10.1016/j.acra.2008.03.017
View details for PubMedID 18790392
Although deep white-matter brain lesions are seen on magnetic resonance imaging in about one third of elderly subjects, their clinical significance is not known. In 1984, we studied three retired teachers who had extensive deep white-matter brain lesions on magnetic resonance imaging, yet functioned cognitively at an above-average level. Blinded review of 1981 computed tomographic scans revealed patchy white-matter lucencies for two of the subjects. Repeated magnetic resonance imaging in 1987 showed that the deep white-matter brain lesions were at least as extensive as in the initial study. One subject had developed renal failure, while the other two continued to function at a high level with no evidence of cognitive decline or psychiatric or neurologic impairment. The presence of extensive deep white-matter brain lesions for up to 7 years in two subjects whose cognitive, behavioral, and neurologic functioning is unimpaired suggests that deep white-matter brain lesions do not necessarily indicate a clinically significant central nervous system disease process.
View details for Web of Science ID A1990CR85100002
View details for PubMedID 2306163
Quantification of ventricular and sulcal volumes from the computed tomographic (CT) scans of 45 schizophrenic patients and 57 normal controls was carried out using a semi-automated computerized approach. The sizes of all cerebrospinal fluid spaces measured were significantly related to age in the control population. An age regression model was used to compare patients and controls. Schizophrenics had slightly larger ventricles and considerably larger sulci than controls. Enlargement of the ventricles and sulci was not correlated with measures of negative symptoms or neuropsychological impairment. The CT scans of eight very ill chronically institutionalized schizophrenics were also analyzed. Their CT findings did not differ significantly from the larger group of schizophrenics studied. Our results show that the cerebral atrophy found in schizophrenia is diffuse in nature and does not relate clearly to measures of disease severity or chronicity.
View details for Web of Science ID A1988P224900004
View details for PubMedID 3382323
Presented here is a modification of a previously developed, computed, semiautomated system for quantifying the amount of CSF and tissue on brain CT scans. The technique automatically strips skull from brain and applies a two-dimensional high-pass filter to reduce spectral-shift artifact. The resultant images are presented along with the raw images, section by section, on a screen for fluid-tissue differentiation by a human scorer. This is accomplished by adjusting a one-bit display of the filtered image until a satisfactory separation threshold is found. Data can be summed within or across sections to provide measures of CSF volume in specific regions of interest such as the ventricles and sulci. A major advantage is the improved accuracy of sulcal measurement. This method has been applied to scans of 57 community volunteers, 20-84 years old. High correlations have been established between rankings performed by an experienced clinician and automated rankings (r = 0.88 with rankings based on ventricular size, and r = 0.83 with rankings based on sulcal size). Furthermore, significant correlations were found between computed measures of ventricular size and age and between sulcal widening and age.
View details for Web of Science ID A1986D210700004
View details for PubMedID 3734197
The planimetric measurement of the area of the ventricles on a computed tomographic section is a convenient and useful method of assessing ventricular size when more sophisticated techniques are not available. It is commonly reported as a planimetric ventricular-brain ratio or VBR. Ventricular size is related to cranial size in normal adults which provides a rationale for the use of a ratio of areas. The ratio might not be an appropriate measure to use when studying conditions acquired in childhood. Guidelines are suggested for the use of planimetric methods to prevent bias in the experimental results.
View details for Web of Science ID A1983QK88300006
View details for PubMedID 6574540
Recent findings of enlarged ventricles and sulcal widening in the computed tomographic (CT) scans of schizophrenic subjects have raised questions about the etiology and treatment of this disorder. Measures obtained from computerized analyses of CT scans of 30 schizophrenic and 33 normal subjects showed no significant difference between the groups in ventricular or sulcal fluid volumes. The discrepancy between our findings and those of other investigators may have been due to different measurement techniques or to differences in the samples. A second study was undertaken to examine the first possibility. Its results suggest that our findings and those based on measurements of planimetric ventricle-brain ratios (VBRs) are highly correlated, but that VBRs from one study may not be compared with those in another to establish population differences. Differences in patient samples appear to constitute an important source of discrepancy in CT findings.
View details for Web of Science ID A1982NZ56000001
View details for PubMedID 7165476
Changes on computed cranial tomography related to aging were studied in 123 normal subjects aged 23 to 88 years. The attenuation value of the white matter in the centrum semiovale decreased with age. When the effect of age was excluded, ventricular and sulcal size did not have an independent effect on the attenuation value. This finding suggests that there may be gradual changes in the chemical composition of white matter with aging.
View details for Web of Science ID A1982MZ45400002
View details for PubMedID 7069007
Cranial computed tomography (CT) scans were obtained in 46 male chronic alcoholics and 31 normal male volunteers. Automated methods were used to estimate the cerebrospinal fluid (CSF) volume in various intracranial zones. Measures of the ventricular fluid volume, the volume of fluid in cortical areas on CT sections at the level of the ventricles, and the sulcal fluid volumes on two convexity sections were computed. The alcoholic group, excluding subjects with chronic liver disease, had significantly more fluid than the control group on all sulcal measures. The group difference on the ventricular measure fell short of significance. Within the alcoholic group, no significant correlation was found between the number of years of alcoholism and any fluid measure when normal age effects were taken into account. A striking degree of variability in the sulcal volumes was observed within the alcoholic group, with many subjects showing normal values while a large group showed markedly elevated values. Further studies will be necessary to determine the significance of these variations.
View details for Web of Science ID A1982PE56600002
View details for PubMedID 6957902
A semiautomated computer analysis was developed to estimate fluid volumes in each hemicranium from computed tomography scans. The method was used to estimate total ventricular and sulcal fluid in 123 normal subjects aged 23-88 years. A wide range of normal values was found. The trend was for the estimated ventricular and sulcal fluid volumes to remain relatively constant until age 60 and then to increase at an increasing rate thereafter. Ventricular enlargement occurred in the absence of sulcal enlargement and vice versa. The estimate of the volume of the ventricles was related to skull size. When this was taken into account, the size of the ventricles showed no sex difference. The cranial cavity was larger in men than in women, and, in both genders, the left hemicranium and the left ventricle were larger on the average than their right counterparts. The limitations of computed cranial tomography as a quantitative tool are discussed in detail.
View details for Web of Science ID A1982NF32600001
View details for PubMedID 6800235
We studied cranial asymmetry in 31 schizophrenics and 32 normal volunteers, all of whom were male and right-handed. Automated measures of computed tomographic (CT) scans were used to estimate global hemicranial and hemispheric ventricular volume differences. A manual method was used to measure hemicranial asymmetries between the widths of the frontal and occipital areas on CT images. The observers making the measurements were unaware of the group membership of the subjects. High reliability was established for the manual method. In contrast to findings by other investigators, no group differences were observed. Methodologic flaws in earlier studies may account for this discrepancy.
View details for Web of Science ID A1982NZ56000002
View details for PubMedID 6984641
Two methods for quantitating cerebrospinal fluid (CSF) volume in each hemicranium and on the total section on cranial computed tomography are described and compared. Both analyses utilize information input by the user, but differ in their treatment of volume averaging. The second analysis (Automated Section Information-I) measured partially volumed CSF more sensitively. Potential inaccuracies due to technical artifacts are summarized.
View details for Web of Science ID A1979HE42900041
View details for PubMedID 461809
The suggestion that the Evans ratio, the ratio of the transverse diameter of the anterior horns of the lateral ventricles to the internal diameter of the skull, was a more significant quantity than the ventricular measurement alone was based on a calculation error. The value of this ratio and other such ratios involving linear skull measurements is unproven.
View details for Web of Science ID A1979HJ59000006
View details for PubMedID 471227
Some of the prior efforts at using postreconstruction dual kilovoltage CT scans to obtain an effective atomic number and electron density are reviewed. A prereconstruction method which avoids beam hardening is applied to a phantom and a beginning clinical trial is described.
View details for Web of Science ID A1978GD97600193
View details for PubMedID 745772
Image quality in cranial computed tomography (CT) was evaluated with phantom and patient studies on both a first (single beam) and a second (multiple beam) generation scanner. When comparable radiation doses were used, there were only minor differences in resolution, low contrast detectability, and noise level. The pattern of noise relative to the size of the area in which it was measured was somewhat different. On patient studies, no differences were found when contrast-material-filled vessel visibility and gray--white matter distinction were analyzed. A lesion was obscured by streak artifacts in one scanner in one of 22 patients scanned on both machines. The major factor in image quality as seen in the two scanners seemed to be in the production of artifacts. This was apparent in artifacts from motion, high contrast discontinuities, beam hardening, and edge enhancement. Multiple factors must be considered in assessing CT image quality. In particular, further studies to quantitatively evaluate noise quality and artifact production are needed.
View details for Web of Science ID A1978FE43300015
View details for PubMedID 263500
Although computed tomography has demonstrated some promise in the direction of quantative radiology, valuable information related to the varying response of tissues to x-rays of different energy is still not utilized on a routine basis. Advancements in a method proposed by Alvarez and Macovski for decomposing dual-spectra CT projection data into its material-dependent Compton and photo-electric components are described. Results are presented to demonstrate that such a separation can be performed. Reconstructed images of separated Compton and photo-electric data obtained from clinical scans are shown. With the improvements described, the Compton images begin to approach the quality of conventional reconstructions with evidence of improved polychromatic correction. The photo-electric data, while separable, suffers from unacceptable noise level. Analysis of this difficulty is presented, with recommendations for future improvement by careful selection of the effective energy of the low energy spectrum. The encouraging results suggest that this technique warrants continued development and evaluation.
View details for Web of Science ID A1978FE29600007
View details for PubMedID 711396
By scanning the brain first at 100 and then at 140 kVp one can distinguish, in vivo, between blood and calcium or iodine solutions. The higher atomic number of calcium or iodine causes their CT values to decrease significantly while blood shows no significant change. This principle was applied to eight patients with hemorrhages, calcified lesions, or iodine-contrast augmented lesions. Hemorrhages showed no significant change with change in kVp, while the lesions containing calcium or iodine showed a highly significant change. This is a useful maneuver for determining the nature of a high-value lesion.
View details for Web of Science ID A1977DL65500021
View details for PubMedID 325601
The CT values of a variety of materials were studied in an EMI and a Syntex head scanner. The presence of bone-simulating rings changed the CT values despite the use of constant length water paths and software corrections. Errors due to beam hardening in CT scanning are discussed. These errors could be of significance, particularly in quantitative studies. The changes in CT values with KV setting of the scanner are used to illustrate their energy dependence and the peculiarities of the scaling system introduced by EMI. The difficulty in specifying a standard scale or unit for CT scanners is discussed.
View details for Web of Science ID A1977DL65500022
View details for PubMedID 866662
A variety of aphasic patients were studied to determine the relationship betweeen lesion size, as demonstrated by cranial computed tomography (CCT), and the type of aphasia, as classified by the Boston Diagnostic Aphasia Examination (BDAE). CCT demonstrated a variety of lesions. Those in nonfluent Broca's aphasics and fluent Wernicke's aphasics were separable into pre-Rolandic and post-Rolandic areas, respectively. Conduction, global, and anomic aphasics had different lesion sites. Correlation of lesion location by CCT with aphasia type supports Geschwind's concepts of aphasia.
View details for Web of Science ID A1977DG71600026
View details for PubMedID 860034
A variety of materials and tissues as well as 3 patients were studied with the EMI scanner using the 100-, 120-, and 140-kVp settings. There was little shift in the EMI value for most tissues over this range, but significant shifts occurred with materials whose effective atomic number was moderately different from that of water. Use of the highest kVp setting may improve visualization of low-contrast images by decreasing the noise caused by statistical fluctuations. This shift in EMI values can be used to determine the approximate amount of material of high atomic number present, such as calcium or iodine.
View details for Web of Science ID A1976BR92300033
View details for PubMedID 935408
Results are described of in vitro biological experimentation using a new through-transmission ultrasonic camera system developed at the Stanford Research Institute. The camera system produces real-time focused, orthographic images of a 15 times 15 cm field. The in vitro studies, which demonstrate the diagnostic potential of the new technique, include transmission images of selected excised organs such as liver, kidney, spleen, and uterus. In addition, preliminary studies evaluating ultrasonic image quality and the effect of out-of-focus structures are discussed.
View details for PubMedID 803985
Real-time transmission ultrasonic imaging of the abdomen in adult patients has been accomplished with a new camera system developed by Stanford Research Institute. Some inherent limitations of the transmission technique are apparent; these include obscuration of some structures by overlying bone or gas-filled organs. Other limitations produced by diffraction and refraction effects of the ultrasound beam in complex objects may be eliminated by additional research effort. With further improvements, this camera system may become a useful diagnostic instrument.
View details for Web of Science ID A1975AU53200029
View details for PubMedID 1178873