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Object The purpose of this study was to report the prevalence of neurosurgeons with both medical degrees (MDs) and doctorates (PhDs) at top-ranked US academic institutions and to assess whether the additional doctorate education is associated with substantive career involvement in academia as well as greater success in procuring National Institutes of Health (NIH) research funding compared with an MD-only degree. Methods The authors reviewed the training of neurosurgeons across the top 10 neurosurgery departments chosen according to academic impact (h index) to examine whether MD-PhD training correlated significantly with career outcomes in academia. Results Six hundred thirteen neurosurgery graduates and residents between the years 1990 and 2012 were identified for inclusion in this analysis. Both MD and PhD degrees were held by 121 neurosurgeons (19.7%), and an MD alone was held by 492. Over the past 2 decades, MD-PhD trainees represented a gradually increasing percentage of neurosurgeons, from 10.2% to 25.7% (p < 0.01). Of the neurosurgeons with MD-PhD training, a greater proportion had appointments in academic medicine compared with their MD-only peers (73.7% vs 52.3%, p < 0.001). Academic neurosurgeons with both degrees were also more likely to have received NIH funding (51.9% vs 31.8%, p < 0.05) than their single-degree counterparts in academia. In a national analysis of all active NIH R01 grants awarded in neurosurgery, MD-PhD investigators held a disproportionate number, more than 4-fold greater than their representation in the field. Conclusions Dual MD-PhD training is a significant factor that may predict active participation in and funding for research careers among neurological surgeons at top-ranked academic institutions. These findings and their implications are of increasing relevance as the population of neurosurgeons with dual-degree training continues to rise.

The purpose of our study was to evaluate the effect of varying volumes and rates of contrast material, use of a saline chaser, and cardiac output on aortic enhancement characteristics in MDCT angiography (MDCTA) using a physiologic phantom.Volumes of 75, 100, and 125 mL of iopamidol, 370 mg I/mL, were administered at rates of 4, 6, and 8 mL/s. The effect of a saline chaser (50 mL of normal saline, 8 mL/s) was evaluated for each volume and rate combination. Normal, reduced (33% and 50%), and increased (25%) cardiac outputs were simulated. Peak aortic enhancement and duration of peak aortic enhancement were recorded. Analysis of variance models were run with these effects, and the estimated mean levels for the sets of factor combinations were determined.Lowering the volume of contrast material resulted in reduced peak enhancement (example, -56.2 HU [p0.0001] with 75 vs 125 mL) and reduced duration of 75% peak enhancement (example, -9.0 seconds [p0.0001] with 75 vs 125 mL). Increasing the rate resulted in increased peak enhancement (example, 104.5 HU [p0.0001] with a rate of 8 vs 4 mL/s) and decreased duration of 75% peak enhancement (example, -13.0 seconds [p0.001]). Use of a saline chaser resulted in increased peak enhancement, and this increase was inversely proportional to contrast material volume. Peak enhancement increased when reduced cardiac output was simulated. Peak enhancement decreased when increased cardiac output was simulated.Reducing contrast material volume from 125 to 75 mL, increasing the rate to 6 or 8 mL/s, and use of a saline chaser result in an aortic enhancement profile that better matches the approximately 5-second imaging window possible with 64-MDCTA of the abdomen and pelvis. Even smaller volumes of contrast material may be adequate in patients with reduced cardiac output.

Rationale and Objectives The purpose of this study was to evaluate the effect of reduced tube current (dose) on lung nodule detection in pediatric multidetector array computed tomography (MDCT). Materials and Methods The study included normal clinical chest MDCT images of 13 patients (aged 1–7 years) scanned at tube currents of 70 to 180 mA. Calibrated noise addition software was used to simulate cases as they would have been acquired at 70 mA (the lowest original tube current), 35 mA (50% reduction), and 17.5 mA (75% reduction). Using a validated nodule simulation technique, small lung nodules of 3 to 5 mm in diameter were inserted into the cases, which were then randomized and rated independently by three experienced pediatric radiologists for nodule presence on a continuous scale ranging from zero (definitely absent) to 100 (definitely present). The observer data were analyzed to assess the influence of dose on detection accuracy using the Dorfman-Berbaum-Mets method for multiobserver, multitreatment receiver-operating characteristic (ROC) analysis and the Williams trend test. Results The areas under the ROC curves were 0.95, 0.91, and 0.92 at 70, 35, and 17.5 mA, respectively, with standard errors of 0.02 and interobserver variability of 0.02. The Dorfman-Berbaum-Mets method and the Williams trend test yielded P values for the effect of dose of .09 and .05, respectively. Conclusion Tube current (dose) has a weak effect on the detection accuracy of small lung nodules in pediatric MDCT. The effect on detection accuracy of a 75% dose reduction was comparable to interobserver variability, suggesting a potential for dose reduction.

The purpose of this study was to develop and validate a technique for three-dimensional (3D) modelling of small lung nodules on paediatric multidetector array computed tomography (MDCT) images. Clinical images were selected from 21 patients (18 years old) who underwent MDCT examinations. Sixteen of the patients had one or more real lung nodules with diameters between 2.5 and 6 mm. A mathematical simulation technique was developed to emulate the 3D characteristics of the real nodules. To validate this technique, MDCT images of 34 real nodules and 55 simulated nodules were randomised and rated independently by four experienced paediatric radiologists on a continuous scale of appearance between 0 (definitely not real) and 100 (definitely real). Receiver operating characteristic (ROC) analysis, t-test, and equivalence test were performed to assess the radiologists' ability to distinguish between simulated and real nodules. The two types of nodules were also compared in terms of measured shape and contrast profile irregularities. The areas under the ROC curves were 0.59, 0.60, 0.40, and 0.63 for the four observers. Mean score differences between simulated and real nodules were -8, -11, 13, and -4 for the four observers with p-values of 0.17, 0.06, 0.17, and 0.26, respectively. The simulated and real nodules were perceptually equivalent and had comparable shape and contrast profile irregularities. In conclusion, mathematical simulation is a feasible technique for creating realistic small lung nodules on paediatric MDCT images.

To determine the effect of two pairs of echo times (TEs) for in-phase (IP) and opposed-phase (OP) 3.0-T magnetic resonance (MR) imaging on (a) quantitative analysis prospectively in a phantom study and (b) diagnostic accuracy retrospectively in a clinical study of adrenal tumors, with use of various reference standards in the clinical study.A fat-saline phantom was used to perform IP and OP 3.0-T MR imaging for various fat fractions. The institutional review board approved this HIPAA-compliant study, with waiver of informed consent. Single-breath-hold IP and OP 3.0-T MR images in 21 patients (14 women, seven men; mean age, 63 years) with 23 adrenal tumors (16 adenomas, six metastases, one adrenocortical carcinoma) were reviewed. The MR protocol involved two acquisition schemes: In scheme A, the first OP echo (approximately 1.5-msec TE) and the second IP echo (approximately 4.9-msec TE) were acquired. In scheme B, the first IP echo (approximately 2.4-msec TE) and the third OP echo (approximately 5.8-msec TE) were acquired. Quantitative analysis was performed, and analysis of variance was used to test for differences between adenomas and nonadenomas.In the phantom study, scheme B did not enable discrimination among voxels that had small amounts of fat. In the clinical study, no overlap in signal intensity (SI) index values between adenomas and nonadenomas was seen (P.05) with scheme A. However, with scheme B, no overlap in the adrenal gland SI-to-liver SI ratio between adenomas and nonadenomas was seen (P.05). With scheme B, no overlap in adrenal gland SI index-to-liver SI index ratio between adenomas and nonadenomas was seen (P.05).This initial experience indicates SI index is the most reliable parameter for characterization of adrenal tumors with 3.0-T MR imaging when obtaining OP echo before IP echo. When acquiring IP echo before OP echo, however, nonadenomas can be mistaken as adenomas with use of the SI index value.

The purpose of this study was to evaluate radiologists' agreement when using a 10-point scale of abnormal findings designed to standardize reporting of abdominal radiographs in neonates or infants with suspected necrotizing enterocolitis.A 10-point scale of radiographic findings was devised at our institution and was in use for approximately 18 months before the initiation of this study. After institutional review board approval, 88 abdominal radiographs (anteroposterior and cross-table lateral) were randomly selected for review, allowing for an equal distribution of examinations throughout the scale according to the original examination report. The mean age of the patients in the total study population was 24.9 days (range, 0-56 days); 61 patients (47.3%) were girls and 68 (52.7%) were boys. Four pediatric radiologists having 20, 13, 7, and 5 years of experience scored images twice at least 4 weeks apart according to the scale, which was designed to characterize certainty and severity of disease in neonates and infants with possible necrotizing enterocolitis. Interobserver and intraobserver agreement was assessed by applying weighted kappa statistics. Operative and pathology reports were reviewed.The average intraobserver weighted kappa value was 0.792 (SD, 0.025; range, 0.635-0.946). The average interobserver weighted kappa value was 0.665 (SD, 0.035, range, 0.574-0.898).Substantial intraobserver and interobserver agreement was found when radiologists used a 10-point scale to report abnormal findings on abdominal radiographs in neonates or infants with suspected necrotizing enterocolitis. This scale warrants further evaluation as a potentially useful clinical tool.

The authors report interim clinical results from an ongoing NIH-sponsored trial to evaluate digital chest tomosynthesis for improving detectability of small lung nodules. Twenty-one patients undergoing computed tomography (CT) to follow up lung nodules were consented and enrolled to receive an additional digital PA chest radiograph and digital tomosynthesis exam. Tomosynthesis was performed with a commercial CsI/a-Si flat-panel detector and a custom-built tube mover. Seventy-one images were acquired in 11 s, reconstructed with the matrix inversion tomosynthesis algorithm at 5-mm plane spacing, and then averaged (seven planes) to reduce noise and low-contrast artifacts. Total exposure for tomosynthesis imaging was equivalent to that of 11 digital PA radiographs (comparable to a typical screen-film lateral radiograph or two digital lateral radiographs). CT scans (1.25-mm section thickness) were reviewed to confirm presence and location of nodules. Three chest radiologists independently reviewed tomosynthesis images and PA chest radiographs to confirm visualization of nodules identified by CT. Nodules were scored as: definitely visible, uncertain, or not visible. 175 nodules (diameter range 3.5-25.5 mm) were seen by CT and grouped according to size: 10 mm. When considering as true positives only nodules that were scored definitely visible, sensitivities for all nodules by tomosynthesis and PA radiography were 70% (+/- 5%) and 22% (+/- 4%), respectively, (p < 0.0001). Digital tomosynthesis showed significantly improved sensitivity of detection of known small lung nodules in all three size groups, when compared to PA chest radiography.

Under typical dark conditions encountered in diagnostic reading rooms, a reader's pupils will contract and dilate as the visual focus intermittently shifts between the high luminance display and the darker background wall, resulting in increased visual fatigue and the degradation of diagnostic performance. A controlled increase of ambient lighting may, however, reduce the severity of these pupillary adjustments by minimizing the difference between the luminance level to which the eyes adapt while viewing an image (L{sub adp}) and the luminance level of diffusely reflected light from the area surrounding the display (L{sub s}). Although ambient lighting in reading rooms has conventionally been kept at a minimum to maintain the perceived contrast of film images, proper Digital Imaging and Communications in Medicine (DICOM) calibration of modern medical-grade liquid crystal displays can compensate for minor lighting increases with very little loss of image contrast. This paper describes two psychophysical studies developed to evaluate and refine optimum reading room ambient lighting conditions through the use of observational tasks intended to simulate real clinical practices. The first study utilized the biologic contrast response of the human visual system to determine a range of representative L{sub adp} values for typical medical images. Readers identified lowmore » contrast horizontal objects in circular foregrounds of uniform luminance (5, 12, 20, and 30 cd/m{sup 2}) embedded within digitized mammograms. The second study examined the effect of increased ambient lighting on the detection of subtle objects embedded in circular foregrounds of uniform luminance (5, 12, and 35 cd/m{sup 2}) centered within a constant background of 12 cd/m{sup 2} luminance. The images were displayed under a dark room condition (1 lux) and an increased ambient lighting level (50 lux) such that the luminance level of the diffusely reflected light from the background wall was approximately equal to the image L{sub adp} value of 12 cd/m{sup 2}. Results from the first study demonstrated that observer true positive and false positive detection rates and true positive detection times were considerably better while viewing foregrounds at 12 and 20 cd/m{sup 2} than at the other foreground luminance levels. Results from the second study revealed that under increased room illuminance, the average true positive detection rate improved a statistically significant amount from 39.3% to 55.6% at 5 cd/m{sup 2} foreground luminance. Additionally, the true positive rate increased from 46.4% to 56.6% at 35 cd/m{sup 2} foreground luminance, and decreased slightly from 90.2% to 87.5% at 12 cd/m{sup 2} foreground luminance. False positive rates at all foreground luminance levels remained approximately constant with increased ambient lighting. Furthermore, under increased room illuminance, true positive detection times declined at every foreground luminance level, with the most considerable decrease (approximately 500 ms) at the 5 cd/m{sup 2} foreground luminance. The first study suggests that L{sub adp} of typical mammograms lies between 12 and 20 cd/m{sup 2}, leading to an optimum reading room illuminance of approximately 50-80 lux. Findings from the second study provide psychophysical evidence that ambient lighting may be increased to a level within this range, potentially improving radiologist comfort, without deleterious effects on diagnostic performance.« less

To retrospectively assess the diagnostic performance of time-resolved magnetic resonance (MR) angiography in the detection of stenoses and occlusions in the central veins of the chest, with angiographic and surgical findings and consensus readings serving as the reference standard.Institutional review board approval was obtained, and the informed consent requirement was waived for this HIPAA-compliant study. Retrospective analysis was performed with 27 consecutive patients (12 male, 15 female; age range, 16-67 years) who underwent MR venography of the central veins. Six radiologists with varying levels of experience interpreted the studies. For each study, the readers were presented with time-resolved maximum intensity projection (MIP) images only, high-spatial-resolution images only, or both. Sensitivity and specificity were calculated for detection of stenoses and occlusions, as well as for confidence levels, study interpretation time, and determination of the side of the body on which upper extremity contrast material injection was performed.The addition of time-resolved angiographic images to the high-spatial-resolution images resulted in improved specificity in the detection of venous occlusions (0.99 vs 0.96, P = .03), in reader confidence (P.001), and in the ability to infer the side of injection (83% correct compared with 32% correct, P.001), without increasing the average time required for study interpretation. Use of time-resolved angiographic data sets as a stand-alone technique had high sensitivity (0.95) but only moderate specificity (0.56) in the detection of venous stenoses or occlusions.Time-resolved angiographic images are a useful adjunct to high-spatial-resolution images in the evaluation of central venous stenoses and occlusions.

The objective of our study was to test the hypothesis that the finding of hyperintense hippocampal signal intensity on T2-weighted MR images soon after febrile status epilepticus is associated with subsequent hippocampal volume loss and persistent abnormal signal intensity on T2-weighted images (i.e., mesial temporal sclerosis).Eleven children (mean age, 25 months) underwent initial MRI that included coronal temporal lobe imaging within 72 hours of febrile status epilepticus and follow-up imaging from 3 to 23 months later (mean, 9 months). A neuroradiologist blinded to clinical history graded initial and follow-up hippocampal signal intensity on a scale from 0 (normal) to 4 (markedly increased). Two blinded observers measured hippocampal volumes on initial and follow-up MR studies using commercially available software and volumes from 30 healthy children (mean age, 6.3 years). Initial signal intensity and hippocampal volume changes were compared using Kendall tau correlation coefficients.On initial imaging, hyperintense signal intensity ranging from 1 (minimally increased) to 4 (markedly increased) was seen in seven children. Four children had at least one hippocampus with moderate or marked signal abnormality, three children had a hippocampus with mild or minimal abnormality, and four children had normal signal intensity. The Kendall tau correlation coefficient between signal intensity increase and volume change was -0.68 (p0.01). Five children (two with temporal lobe epilepsy and two with complex partial seizures) had hippocampal volume loss and increased signal intensity on follow-up imaging, meeting the criteria for mesial temporal sclerosis.MRI findings of a markedly hyperintense hippocampus in children with febrile status epilepticus was highly associated with subsequent mesial temporal sclerosis.

The objective of this study was to compare the contrast-detail performance of five different commercial liquid crystal displays(LCDs) to other LCD and cathode-ray tube (CRT) displays for medical applications. A contrast-detail phantom, supplemented with 5 in. of acrylic, was imaged on a commercial digital radiographicsystem using techniques comparable to chest radiography. The phantom design enabled observer evaluation by a four-alternative forced choice paradigm. The acquired images were independently scored by five observers on five medicaldisplay devices: a 5 megapixel monochrome LCD, a 3 megapixel monochrome LCD, a 9 megapixel color LCD, a 5 megapixel monochrome CRT, and a mammographic-grade monochrome CRT. The data were analyzed using the method suggested by the manufacturer based on a nearest neighbor correction technique. They were further analyzed using a logistic regression response model with a natural threshold using an overall chi-square test for display type followed by pairwise comparisons for individual display performance. The differences between the display devices were small. The standard analysis of the results based on the manufacturer-recommended method did not yield any statistically discernible trend among displays. The logistic regression analysis, however, indicated that the 5 megapixel monochrome LCD was statistically significantly ( p 0.0001 ) superior to the others, followed by the 3 megapixel monochrome LCD ( p 0.0001 ) . The three other displays exhibited lower but generally similar performance characteristics. The findings suggest that 5 and 3 megapixel monochrome LCDs provide comparable but subtly superior contrast detectability than other tested displays, with the former performing slightly better in the detection of subtle and fine details.

To prospectively evaluate, for the depiction of simulated hypervascular liver lesions in a phantom, the effect of a low tube voltage, high tube current computed tomographic (CT) technique on image noise, contrast-to-noise ratio (CNR), lesion conspicuity, and radiation dose.A custom liver phantom containing 16 cylindric cavities (four cavities each of 3, 5, 8, and 15 mm in diameter) filled with various iodinated solutions to simulate hypervascular liver lesions was scanned with a 64-section multi-detector row CT scanner at 140, 120, 100, and 80 kVp, with corresponding tube current-time product settings at 225, 275, 420, and 675 mAs, respectively. The CNRs for six simulated lesions filled with different iodinated solutions were calculated. A figure of merit (FOM) for each lesion was computed as the ratio of CNR2 to effective dose (ED). Three radiologists independently graded the conspicuity of 16 simulated lesions. An anthropomorphic phantom was scanned to evaluate the ED. Statistical analysis included one-way analysis of variance.Image noise increased by 45% with the 80-kVp protocol compared with the 140-kVp protocol (P.001). However, the lowest ED and the highest CNR were achieved with the 80-kVp protocol. The FOM results indicated that at a constant ED, a reduction of tube voltage from 140 to 120, 100, and 80 kVp increased the CNR by factors of at least 1.6, 2.4, and 3.6, respectively (P.001). At a constant CNR, corresponding reductions in ED were by a factor of 2.5, 5.5, and 12.7, respectively (P.001). The highest lesion conspicuity was achieved with the 80-kVp protocol.The CNR of simulated hypervascular liver lesions can be substantially increased and the radiation dose reduced by using an 80-kVp, high tube current CT technique.

The purpose of this study was to use diffusion-weighted and diffusion tensor imaging to investigate the status of cerebral white matter (WM) at term gestation and the rate of WM maturation throughout the first year of life in healthy infants.Fifty-three children (35 boys) ranging in age from 1.5 weeks premature to 51.5 weeks (mean age, 22.9 weeks) underwent conventional MRI, diffusion imaging in three directions (b = 1,000 s/mm2), and diffusion tensor imaging with gradient encoding in six directions, all on a 1.5-T MRI system. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were measured in three deep WM structures (posterior limb of internal capsule, genu, and splenium of corpus callosum) and two peripheral WM regions (associational WM underlying prefrontal and posterior parietal cortex) with a standard region of interest (44 +/- 4 cm2). ADC and FA were expressed as a percentage of corresponding values measured in a group of healthy young adults. Mean ADC and FA values for deep and peripheral WM were plotted against gestational age normalized to term. The data were fit best with a broken-line linear regression model with a breakpoint at 100 days. ADC and FA values at term were estimated according to the intercept of the initial linear period (before day 100) with day 0. The slope of the linear fits was used to determine the rate of WM maturation in both the early and the late (after day 100) periods. Multivariate analysis of variance tests were used to compare deep and peripheral WM structures at term and at representative early and late ages (days 30 and 200) and to compare rates of ADC and FA maturation in early and late periods within the first year.At term, peripheral WM was less mature than deep WM according to results of extrapolation of ADC and FA values in the first 100 days of life to day 0 (p0.01). Mean ADC and FA value (percentage of mean adult value) for peripheral WM were 1.32 x 10(-3) mm2/s (163%) and 0.16 (32%), respectively, and 1.09 x 10(-3) mm2/s (143%) and 0.36 (54%), respectively, for deep WM. On day 30 and day 200, estimated mean ADC and FA continued to show greater diffusion (higher ADC) and less anisotropy (lower FA value) in peripheral WM (p0.01). During the first year of postnatal life, both ADC and FA matured at higher rates before postnatal day 100 compared with a later time. Differences were observed in rates of maturation in the first 100 days when rates of decrease in ADC and increase in FA were compared between peripheral WM and deep WM; however, the maturational trends differed whether ADC or FA was examined. The early rate of ADC decrease (maturation) was twice as great for peripheral WM than for deep WM (p0.01) unexpectedly, but the opposite pattern was observed for FA. The early rate of FA increase (maturation) was approximately one half as great for peripheral WM as for deep WM (p = 0.01). Throughout the rest of the first year, no differences were observed in the rates of change in either index between peripheral WM and deep WM.At term, both ADC and FA differ significantly in peripheral WM and deep WM, deep WM structures being more mature. Both deep WM and peripheral WM mature more rapidly during approximately the first 3 months in comparison with the rest of the first year. Unexpected differences in early (first 100 days) rates of maturation assessed with diffusion-weighted (ADC) and diffusion tensor (FA) imaging suggest that these two techniques may be sensitive to different aspects of WM maturation in the early perinatal period.

The effect of reduction in dose levels normally used in mammographic screening procedures on the detection of breast lesions were analyzed. Four types of breast lesions were simulated and inserted into clinically-acquired digital mammograms. Dose reduction by 50% and 75% of the original clinically-relevant exposure levels were simulated by adding corresponding simulated noise into the original mammograms. The mammograms were converted into luminance values corresponding to those displayed on a clinical soft-copy display station and subsequently analyzed by Laguerre-Gauss and Gabor channelized Hotelling observer models for differences in detectability performance with reduction in radiation dose. Performance was measured under a signal known exactly but variable detection task paradigm in terms of receiver operating characteristics (ROC) curves and area under the ROC curves. The results suggested that luminance mapping of digital mammograms affects performance of model observers. Reduction in dose levels by 50% lowered the detectability of masses with borderline statistical significance. Dose reduction did not have a statistically significant effect on detection of microcalcifications. The model results indicate that there is room for optimization of dose level in mammographic screening procedures.

To prospectively evaluate the use of lean body weight (LBW) as the main determinant of the volume and rate of contrast material administration during multi-detector row computed tomography of the liver.This HIPAA-compliant study had institutional review board approval. All patients gave written informed consent. Four protocols were compared. Standard protocol involved 125 mL of iopamidol injected at 4 mL/sec. Total body weight (TBW) protocol involved 0.7 g iodine per kilogram of TBW. Calculated LBW and measured LBW protocols involved 0.86 g of iodine per kilogram and 0.92 g of iodine per kilogram calculated or measured LBW for men and women, respectively. Injection rate used for the three experimental protocols was determined proportionally on the basis of the calculated volume of contrast material. Postcontrast attenuation measurements during portal venous phase were obtained in liver, portal vein, and aorta for each group and were summed for each patient. Patient-to-patient enhancement variability in same group was measured with Levene test. Two-tailed t test was used to compare the three experimental protocols with the standard protocol.Data analysis was performed in 101 patients (25 or 26 patients per group), including 56 men and 45 women (mean age, 53 years). Average summed attenuation values for standard, TBW, calculated LBW, and measured LBW protocols were 419 HU +/- 50 (standard deviation), 443 HU +/- 51, 433 HU +/- 50, and 426 HU +/- 33, respectively (P = not significant for all). Levene test results for summed attenuation data for standard, TBW, calculated LBW, and measured LBW protocols were 40 +/- 29, 38 +/- 33 (P = .83), 35 +/- 35 (P = .56), and 26 +/- 19 (P = .05), respectively.By excluding highly variable but poorly perfused adipose tissue from calculation of contrast medium dose, the measured LBW protocol may lessen patient-to-patient enhancement variability while maintaining satisfactory hepatic and vascular enhancement.

To prospectively determine quantitatively and qualitatively the timing of maximal enhancement of the normal small-bowel wall by using contrast material-enhanced multi-detector row computed tomography (CT).This HIPAA-compliant study was approved by the institutional review board. After information on radiation risk was given, written informed consent was obtained from 25 participants with no history of small-bowel disease (mean age, 58 years; 19 men) who had undergone single-level dynamic CT. Thirty seconds after the intravenous administration of contrast material, a serial dynamic acquisition, consisting of 10 images obtained 5 seconds apart, was performed. Enhancement measurements were obtained over time from the small-bowel wall and the aorta. Three independent readers qualitatively assessed small-bowel conspicuity. Quantitative and qualitative data were analyzed during the arterial phase, the enteric phase (which represented peak small-bowel mural enhancement), and the venous phase. Statistical analysis included paired Student t test and Wilcoxon signed rank test with Bonferroni correction. A P value less than .05 was used to indicate a significant difference.The mean time to peak enhancement of the small-bowel wall was 49.3 seconds +/- 7.7 (standard deviation) and 13.5 seconds +/- 7.6 after peak aortic enhancement. Enhancement values were highest during the enteric phase (P.05). Regarding small-bowel conspicuity, images obtained during the enteric phase were most preferred qualitatively; there was a significant difference between the enteric and arterial phases (P.001) but not between the enteric and venous phases (P = .18).At multi-detector row CT, peak mural enhancement of the normal small bowel occurs on average about 50 seconds after intravenous administration of contrast material or 14 seconds after peak aortic enhancement.

The purposes of this study were to determine the accuracy of abdominal radiography in the detection of acute small-bowel obstruction (SBO), to assess the role of reviewer experience, and to evaluate individual radiographic signs of SBO.A retrospective study was performed in which the subjects were 90 patients with suspected SBO who underwent CT and abdominal radiography within 48 hours of each other. The patients were enrolled from June 1, 2003, to February 2004. Twenty-nine of the patients had proven SBO. Hard-copy radiographs were reviewed by three groups of radiologists: senior staff, junior staff, and second-year radiology residents. Each reviewer evaluated the quality of the radiographs, patient position for acquisition of the radiographs, and whether SBO was present. The reviewers rated their confidence on a five-point scale and recorded the presence or absence of specific radiographic signs of SBO. Chi-square tests were used to compare the three groups. A statistically significant finding was considered p0.05. Receiver operating characteristic (ROC) curves were fit with a 10-point confidence scale.The sensitivity for SBO among the six reviewers ranged from 59% to 93%. The senior staff members were significantly more accurate. The mean sensitivity, specificity, and accuracy for all six reviewers were 82%, 83%, and 83%, respectively. Three radiographic signs were highly significant (p0.001): two or more air-fluid levels, air-fluid levels wider than 2.5 cm, and air-fluid levels differing more than 5 mm from one another in the same loop of small bowel. ROC analysis showed that senior staff is significantly more accurate than the other groups in the detection of acute SBO.Our results confirmed that abdominal radiographs are accurate in the detection of acute SBO, that more-experienced radiologists are more accurate than less-experienced reviewers in the evaluation of abdominal radiographs, and that three types of air-fluid levels are highly predictive of the presence of SBO.

Rationale and Objectives To compare two display technologies, cathode ray tube (CRT) and liquid crystal display (LCD), in terms of diagnostic accuracy for several common clinical tasks in digital mammography. Materials and Methods Simulated masses and microcalcifications were inserted into normal digital mammograms to produce an image set of 400 images. Images were viewed on one CRT and one LCD medical-quality display device by five experienced breast-imaging radiologists who rated the images using a categorical rating paradigm. The observer data were analyzed to determine overall classification accuracy, overall lesion detection accuracy, and accuracy for four specific diagnostic tasks: detection of benign masses, malignant masses, and microcalcifications, and discrimination of benign and malignant masses. Results Radiologists had similar overall classification accuracy (LCD: 0.83 ± 0.01, CRT: 0.82 ± 0.01) and lesion detection accuracy (LCD: 0.87 ± 0.01, CRT: 0.85 ± 0.01) on both displays. The difference in accuracy between LCD and CRT for the detection of benign masses, malignant masses, and microcalcifications, and discrimination of benign and malignant masses was –0.019 ± 0.009, 0.020 ± 0.008, 0.012 ± 0.013, and 0.0094 ± 0.011, respectively. Overall, the two displays did not exhibit any statistically significant difference ( P > .05). Conclusion This study explored the suitability of two different soft-copy displays for the viewing of mammographic images. It found that LCD and CRT displays offer similar clinical utility for mammographic tasks.

Rationale and Objectives The purpose of this study was to calculate the gain in signal-to-noise ratio (SNR) of four human abdominal tissues at 3.0 Tesla (T) compared with standard 1.5 T and to validate this calculation in vivo. Materials and Methods The expected gain in SNR at 3.0 T in the liver, pancreas, spleen, and kidney compared with standard 1.5 T was approximated theoretically for a T2-weighted HASTE (half-Fourier acquisition single-shot turbo spin-echo) and a T1-weighted gradient-echo in- and opposed-phase sequence. Fifteen healthy male subjects underwent abdominal MR imaging using a 1.5 T and 3.0 T scanner. Coronal T2-weighted HASTE images and axial T1-weighted gradient-echo in- and opposed-phase images were acquired using the sequence parameters optimized by the vendor. Results Except for opposed-phased imaging of pancreatic tissue, in vivo adjusted SNR values of all abdominal tissues were significantly higher at 3.0 T for all sequences (P Conclusion High-field abdominal MR imaging at 3.0 T offers significantly higher SNR compared with standard 1.5 T MR imaging.

PURPOSE To determine radiation dose to the hands of interventional radiologists during restoration of flow to thrombosed dialysis access grafts. MATERIALS AND METHODS Sixty-two procedures were performed in 54 patients with thrombosed synthetic arteriovenous hemodialysis access grafts. For each procedure, five staff interventional radiologists wore thermoluminescent ring dosimeters on each hand. Overall hand doses were obtained, and patient and graft factors as well as technical factors were analyzed to determine the effects on hand exposure. RESULTS The mean right hand and left hand exposures were 0.78 mSv and 0.55 mSv (78 and 55 mrem), respectively, and there was a significant difference between the two ( P = .01 ). There was a significant difference among the interventionalists, mostly based on the lower doses associated with a single operator ( P ). Not unexpectedly, fluoroscopy times ( P ) and, to a lesser degree, the number of angiographic runs ( P = .05 ) were significant factors influencing hand radiation dose. Patient sex, age and location of the graft, previous thrombosis, the number of previous interventions, and success or failure of the procedure were not significant factors in hand dose. CONCLUSIONS Hand exposure during the restoration of flow to thrombosed dialysis access grafts is relatively high and is greater for the right hand than for the left. The exposures are dependent on technical factors, most notably fluoroscopy times, not on patient-or graft-related factors.

Rationale and Objectives This study presents a method for generating breast masses and microcalcifications in mammography via simulation. This simulation method allows for the creation of large image datasets with particular lesions, which may serve as a useful tool for perception studies measuring imaging system performance. Materials and Methods The study first characterized the radiographic appearance of both masses and microcalcifications, examining the following five properties: contrast, edge gradient profile of masses, edge characteristics of masses, shapes of individual microcalcifications, and shapes of microcalcification distributions. The characterization results then guided the development of routines that created simulated masses and microcalcifications. The quality of the simulations was verified by experienced breast imaging radiologists who evaluated simulated and real lesions and rated whether a given lesion had a realistic appearance. Results The radiologists rated real and simulated lesions to have similarly realistic appearances. Using receiver operating characteristic analysis to characterize the degree of similarity, the results showed an Az of 0.68 ± 0.07 for benign masses, 0.65 ± 0.07 for malignant masses, and 0.62 ± 0.07 for microcalcifications, thus showing notable overlap in the simulated and real lesion ratings. Conclusion This research introduced a new approach for simulating breast masses and microcalcifications that relied on anatomic characteristics measured from real lesions. Results from an observer performance experiment indicate that our simulation routine produced realistic simulations of masses and microcalcifications as judged by expert radiologists.

An important approach to reconstructing PET and SPECT (PET/SPECT) radiotracer images is to utilize high-resolution information from registered MRI or CT (MRI/CT) images. These methods depend on accurate registration of PET/SPECT and MRI/CT images. Herein, we consider registration via optimization of a PET/SPECT image-reconstruction objective function which includes the registration parameters. Potential benefits of this approach include 1) modeling, within the registration process, of PET/SPECT noise and PET/SPECT acquisition effects such as limited spatial resolution, perhaps resulting in more accurate registration and 2) a natural framework for calculating joint uncertainties in registration parameters and radiotracer activity. In cases where the structures imaged by MRI/CT (e.g., gray matter and white matter in the brain) strongly influence the radiotracer distribution, the relatively small number of variables comprised of alignment parameters and regional radiotracer mean activities may account for, not all, but much of the estimable radiotracer distribution, and it may be useful to develop methods for rapid, highly accurate estimation of these few parameters, ultimately embedding such estimation within more general estimation of the full radiotracer distribution. Herein we develop Levenberg-Marquardt simultaneous estimation of regional radiotracer mean activities and the six 3D rigid body translation and rotation alignment parameters. The method is tested by a computer-simulation study. With a PET/SPECT scanner spatial resolution of 0.2 cm FWHM, this study shows translational registration errors of about 0.002 cm and rotational errors which are fractions of a degree. For small regions, estimates of regional mean activities are much closer to true values than are estimates obtained by OSEM using PET/SPECT projection data only.

Architectural distortion (AD) is a sign of malignancy often missed during mammographic interpretation. The purpose of this study was to explore the application of fractal analysis to the investigation of AD in screening mammograms. The study was performed using mammograms from the Digital Database for Screening Mammography (DDSM). The fractal dimension (FD) of mammographic regions of interest (ROIs) was calculated using the circular average power spectrum technique. Initially, the variability of the FD estimates depending on ROI location, mammographic view and breast side was studied on normal mammograms. Then, the estimated FD was evaluated using receiver operating characteristics (ROC) analysis to determine if it can discriminate ROIs depicting AD from those depicting normal breast parenchyma. The effect of several factors such as ROI size, image subsampling and breast density was studied in detail. Overall, the average FD of the normal ROIs was statistically significantly higher than that of the ROIs with AD. This result was consistent across all factors studied. For the studied set of implementation parameters, the best ROC performance achieved was 0.89 +/- 0.02. The generalizability of these conclusions across different digitizers was also demonstrated.

To retrospectively assess the added value of coronal reformations of the abdomen and pelvis from isotropic voxels by using 16-section multi-detector row computed tomography (CT) for the diagnosis of small-bowel obstruction (SBO).This HIPAA-compliant study was approved by the institutional review board of this medical center with a waiver of informed consent. One hundred consecutive patients (40 men and 60 women; mean age, 55 years) suspected of having SBO and abdominal pain underwent 16-section multi-detector row CT with coronal reformations. Twenty-nine patients had a final diagnosis of SBO, and 71 patients did not. Three independent readers blinded to the diagnosis interpreted the CT scout scan, then transverse scans alone, and then transverse plus coronal scans for the presence of SBO and abnormal wall enhancement. Confidence was scored with a 1-5 scale (1 = absent, 5 = present).Mean sensitivity and specificity of CT scout alone, transverse CT alone, and transverse plus coronal CT for the diagnosis of SBO were 88% and 86%, 87% and 87%, and 87% and 90%, respectively (not significant). In patients without SBO, transverse plus coronal CT enhanced confidence in the exclusion of SBO (P = .01). In patients with SBO, transverse plus coronal CT enhanced confidence in the diagnosis of SBO and identification of abnormal wall enhancement (P = .01).Transverse 16-section multi-detector row CT data sets are an excellent test for the diagnosis of SBO, while the addition of coronal reformations obtained from these isotropic data sets adds confidence to the diagnosis and exclusion of SBO.

The purpose of our study was to determine which manuscript reviewer characteristics are most strongly associated with reviewer performance as judged by editors of the American Journal of Roentgenology (AJR).At the AJR, manuscript reviews are rated by the journal editors on a subjective scale from 1 (lowest) to 4, on the basis of the value, thoroughness, and punctuality of the critique. We obtained all scores for AJR reviewers and determined the average score for each reviewer. We also sent a questionnaire to 989 reviewers requesting specific information regarding the age, sex, radiology subspecialty, number of years serving as a reviewer, academic rank, and practice type of the reviewer. The demographic profiles were correlated with the average quality score for each reviewer. Statistical analysis included correlation analysis and analysis of variance modeling. Reviewer quality scores were also correlated with the scoring of individual reviews and ultimate disposition of 196 manuscripts sent to the AJR during the same period.Responses to the questionnaire were obtained from 821 reviewers (83.0%), for whom quality scores were available for 714 (87.0%). Correlation analysis shows that the quality score of reviewers strongly correlated with younger age (p = 0.001). A statistically significant correlation between quality score and practice type was seen (p = 0.008), with reviewers from academic institutions receiving higher scores. No significant correlation was found between quality score and sex (p = 0.72), years of reviewing (p = 0.26), academic rank (p = 0.10), or the ultimate disposition of the manuscript (p = 0.40). The quality score of the reviewers showed no variation by subspecialty (p = 0.99).The highest-rated AJR reviewers tended to be young and from academic institutions. The quality of peer review did not correlate with the sex, academic rank, or subspecialty of the reviewer.

The purpose of our study was to determine the degree to which carotid canal fracture and other CT findings are associated with internal carotid artery (ICA) injury in patients with head trauma.Three neuroradiologists retrospectively evaluated CT scans and cerebral angiograms of 43 patients who underwent cerebral angiography within 7 days after blunt cranial trauma over a 5-year period. Seventeen patients underwent unilateral and 26 had bilateral carotid angiography. Angiograms were evaluated for ICA injury and CT scans were evaluated for carotid canal fracture, brain contusion, subarachnoid hemorrhage, basilar skull fracture, subdural hematoma, soft-tissue swelling, sphenoid sinus air-fluid level, and other skull fracture. We recorded the number of true-positive (+CT, +angiogram), true-negative (-CT, -angiogram), false-positive (+CT, -angiogram), and false-negative (-CT, +angiogram) studies. We determined the sensitivity, specificity, positive predictive value, and negative predictive value for each CT finding.We identified 21 carotid canal fractures in 17 patients. Eleven ICA injuries were seen in 10 patients. Six patients with ICA injury had a carotid canal fracture. The presence of a carotid canal fracture had a sensitivity of 60% and specificity of 67% for detection of injury to the ICA passing through that canal. These values were similar to those for other CT findings.Sensitivity, specificity, positive predictive value, and negative predictive value of carotid canal fracture were only moderately good for determining the presence of ICA injury and were similar to other CT findings not typically associated with ICA injury.

Rationale and objectives We sought to quantify patient preferences for mild, moderate, and severe low back pain via time-tradeoff analysis and utility measurement. Materials and methods Forty-one patients being treated for low back pain in a tertiary care teaching hospital participated in the study. Patients were asked to decide which of three health states they were currently experiencing as well as which of the three health states was the worst experienced during their lifetime. A time-tradeoff analysis was performed, during which patients were asked the amount of time in each of the health states they would exchange for complete resolution of symptoms. We correlated (1) subjects’ current health state with reported utility and (2) degree of previous low back pain with results of time-tradeoff measurements. Results All patients were willing to trade a greater number of life-years for resolution of symptoms given a more severe perceived health state. Utility decreased as severity of back pain scenarios increased, with an average utility of 0.93 ± 0.11 for mild, 0.65 ± 0.21 for moderate, and 0.18 ± 0.17 for severe pain. No significant difference in time-tradeoff among subjects was identified based upon current health state on the day of interview. A statistically significant difference was seen in patients’ willingness to trade time among those who had actually experienced severe pain versus those who had not. Kendall’s correlation revealed that subjects who had experienced severe back pain exhibited significantly lower utilities (P Conclusions As expected, patients with severe low back pain were willing to sacrifice more potential years of life for resolution of symptoms, suggesting time-tradeoff can accurately reflect patient utility. 2. However, we found no correlation between a subject’s current health state and reported utility.

Our objective was to evaluate the role of Valsalva's maneuver during MDCT for the diagnosis and characterization of abdominal wall hernias.From September 2002 to May 2003, 100 consecutive patients (37 men and 63 women; mean age, 53 years) with suspected anterior abdominal wall hernias underwent 4-, 8-, or 16-MDCT with and without Valsalva's maneuver. Patients received both oral and IV contrast material. On a workstation, three independent reviewers evaluated each scan obtained during rest and during Valsalva's maneuver for the following parameters: anteroposterior (AP) diameter of the abdomen; presence, location, and contents of the hernia; and transverse diameter of the fascial defect. The scans were compared to assess for changes in hernia size and contents and to determine whether the hernia would have been overlooked without Valsalva's maneuver. Fisher's exact test, the McNemar test, and Cohen's kappa coefficient were used to assess for significant differences.The three reviewers identified a mean of 72 abdominal wall hernias (72%). The reviewers agreed (kappa = 0.723) with respect to the presence of a hernia. AP diameters increased an average of 1.33 cm during Valsalva's maneuver (p0.001). The transverse diameter of the fascial defect increased an average of 0.66 cm and the AP diameter of the hernia sac increased an average of 0.79 cm during Valsalva's maneuver (p0.001). Fifty percent of the hernias became more apparent with Valsalva's maneuver. Ten percent of the hernias could be detected only on the scan obtained during Valsalva's maneuver. Conversely, in no patients was the hernia detected only on the rest scan.As opposed to scans obtained at rest, scans obtained during Valsalva's maneuver aid in the detection and characterization of suspected abdominal wall hernias. A single scan obtained during Valsalva's maneuver is sufficient to detect 100% of anterior abdominal wall hernias identified on CT.

The purpose of this study was to establish the range of spleen sizes in tall healthy athletes.Sonographic measurements of spleen size and left renal length were performed on 129 college athletes (82 men, 47 women). Length, width, and thickness of the spleen and left renal length were obtained. In addition, the height, weight, and age of each athlete were recorded. Pearson's product moment correlation coefficients were calculated, and linear regression analysis was used to create a model for calculating normative values.The mean body height for men was 74.3 (189 cm) +/-(SD) 3.7 inches (9 cm) and for women was 69.3 (176 cm) +/- 3.7 inches (9 cm). Spleen length was greater than 12 cm in 31.7% of the men (mean spleen length, 11.4 +/- 1.7 cm) and in 12.8% of the women (mean spleen length, 10.3 +/- 1.3 cm). In women, height correlated with spleen length (r = 0.3, p = 0.05), width (r = 0.4, p = 0.01), and volume (r = 0.3, p = 0.02) but not with thickness (r = 0.08, p = 0.6). Spleen length did correlate with left renal length (r = 0.5, p = 0.0005). In men, height correlated with spleen length (r = 0.4, p = 0.0003), width (r = 0.5, p = 0.0001), and volume (r = 0.4, p = 0.0002) and less with thickness (r = 0.3, p = 0.01). Spleen length and left renal length were poorly correlated (r = 0.2, p = 0.04). Regression analysis showed that in women taller than 5 ft 6 inches (168 cm), the mean splenic length of 10 cm increased by 0.1 cm for each 1-inch incremental increase in height. In men taller than 6 ft (180 cm), the mean splenic length of 11 cm increased by 0.2 cm for each 1-inch incremental increase in height.Spleen size correlates with height in tall healthy athletes. Nomograms from this data can be used to gauge the risk of returning to play after episodes of acute splenomegaly, as with infectious mononucleosis.

The objective of this study was to examine the relative influence of manuscript characteristics and peer-reviewer attributes in the assessment of manuscripts.Over a 6-month period, all major papers submitted to the American Journal of Roentgenology (AJR) were entered into a database that recorded manuscript characteristics, demographic profiles of reviewers, and the disposition of the manuscript. Manuscript characteristics included reviewer ratings on five scales (rhetoric, structure, science, import, and overall recommendation); the subspecialty class of the paper; the primary imaging technique; and the country of origin. Demographic profiles of the reviewers included age, sex, subspecialty, years of reviewing, academic rank, and practice type. Statistical analysis included correlation analysis, ordinal logistic regression, and analysis of variance.A total of 445 reviews of 196 manuscripts were the work of 335 reviewers. Of the 196 submitted manuscripts, 20 (10.2%) were accepted, 106 (54.1%) were rejected, and 70 (35.7%) were rejected with the opportunity to resubmit. Regarding manuscript characteristics, we found that the country of origin, score on the science scale, and score on the import scale were statistically significant variables for predicting the final disposition of a manuscript. Of the reviewer attributes, we found a statistically significant association between greater reviewer age and also higher academic rank with lower scores on the import scale. Reviewer concordance was higher for structure, science, and overall scores than on the rhetoric and import scores. Greater variability in the overall scoring of papers could be attributed to the reviewer than the manuscript, but both factors combined explain only 23% of the total variability.At the AJR, manuscript acceptance was most strongly associated with reviewer scoring of the science and import of a major paper and also with the country of origin. Reviewers who were older and of higher academic rank tended to discount the importance of manuscripts.

To evaluate the variability of true-positive and false-positive cues by using a commercially available computer-aided detection (CAD) system for analysis of 50 malignancies in a screening population.Fifty breast cancers detected at screening were analyzed by using a commercially available CAD system. Mean patient age was 62.2 years. Each set of mammograms (craniocaudal and mediolateral oblique views) was digitized and analyzed by the CAD system 10 times. One radiologist compared CAD output with the location of the malignancy at mammography and determined whether each lesion was marked accurately in one mammographic view, both views, or neither. Sensitivity and reproducibility of the CAD system were determined for both case- and image-based analysis.Overall sensitivity of the CAD system when at least one of the two mammographic views was marked correctly (case-base sensitivity) was 82.4%. Sensitivity when each mammographic view was considered separately (image-based sensitivity) was 61.1%. For case-based analysis, variability in true-positive CAD cues was demonstrated for 14 of 50 (28%) cases. For image-based analysis, inconsistency in CAD output was observed in 33 of 100 (33%) mammographic views that contained malignancies detected at screening. However, the CAD system consistently detected 40-43 of the 50 breast cancers in each of the 10 CAD runs. Variability for false-positive marks was significantly greater than that for true-positive marks.Inconsistency was demonstrated for CAD analysis of breast cancers detected at screening. However, the CAD system was reasonably consistent in the overall number of cancers identified from run to run. Greater variability of the CAD system was also demonstrated for false-positive marks, as compared with true-positive marks.

Rationale and objectives The purpose of this study was to compare hepatic enhancement characteristics using two different contrast media injection protocols with multidetector helical computed tomography. Materials and methods Twenty-three patients with known or suspected liver lesions scheduled to undergo biphasic hepatic multidetector helical computed tomography were randomized into one of two groups: (1) 150 mL of iopamidol (300 mgI/mL) at 5 mL/second, or (2) 100 mL of iopamidol (370 mgI/mL) at 4 mL/second. Unenhanced images were acquired initially, followed by both hepatic arterial phase (scan delay, 33 seconds) and portal venous phase (PVP; scan delay, 65 seconds) imaging. Three abdominal radiologists independently graded the images on a scale from 1–5 for enhancement and overall scan quality. Time-attenuation curves were generated from operator-defined region-of-interest measurements of liver parenchyma and aorta. Results Qualitatively, the three reviewers found no significant difference between the two study groups in terms of overall scan quality ( P = .23) or aortic enhancement (hepatic arterial phase, P = .9; PVP, P = .24). However, liver enhancement during the PVP was considered to be less in the Isovue 370 group ( P = .04). Quantitatively, during the hepatic arterial phase, there was no statistically significant difference between the two injection protocols comparing either aortic or hepatic parenchymal enhancement ( P = .62 and .80, respectively). During the PVP, these differences were statistically significant, with both aortic and hepatic parenchymal enhancement lower in the Isovue 370 group ( P P = .04, respectively). Conclusion It is important to consider the amount of iodine injected per second and the duration of the injection when setting up protocols to achieve target organ enhancement. 100 mL of iopamidol 370 at 4 mL/second can be used to obtain images of the liver with good diagnostic quality compared to more conventional protocols using 150 mL of iopamidol 300 at 5 mL/second. However, the degree of liver parenchymal enhancement during the PVP using the latter injection scheme is lower, which in turn could potentially reduce hepatic lesion conspicuity.

The purpose of this study was to correlate the extent of computed tomographic (CT) findings with the severity of respiratory dysfunction in lung transplant recipients with bronchiolitis obliterans syndrome (BOS). Eighty-nine conventional and 61 thin-section CT scans performed in 44 transplant recipients (17 bilateral, 27 single) with BOS were reviewed for mosaic attenuation, degree of bronchial dilation, bronchial thickening, central and peripheral bronchiectasis, mucus plugging, and air trapping. Findings on conventional and thin-section CT scans were correlated with BOS stage for bilateral and single-lung transplant recipients. In bilateral-lung recipients, a significant correlation existed, although weak, between BOS stage and findings of degree of bronchial dilation (P < 0.01), bronchial wall thickening (P = 0.01), peripheral bronchiectasis (P = 0.01), and mosaic attenuation (P = 0.01) on conventional CT; and bronchial wall thickening (P = 0.01) and mosaic attenuation (P = 0.03) on thin-section CT. In single-lung recipients, BOS stage correlated only with the finding of central bronchiectasis (P = 0.02) on conventional CT scans. No correlation was found between the extent of air trapping and BOS stage in either single- or bilateral-lung transplant recipients. CT findings are relatively poor indices of airflow obstruction in lung transplant recipients with BOS, particularly in those with single-lung transplants for emphysema.

The purpose of this study was to evaluate the clinical utility of an investigational flat-panel digital radiography system for low-dose portable neonatal imaging. Thirty image-pairs from neonatal intensive care unit patients were acquired with a commercial Computed Radiography system (Agfa, ADC 70), and with the investigational system (Varian, Paxscan 2520) at one-quarter of the exposure. The images were evaluated for conspicuity and localization of the endings of ancillary catheters and tubes in two observer performance experiments with three pediatric radiologists and three neonatologists serving as observers. The results indicated no statistically significant difference in diagnostic quality between the images from the investigational system and from CR. Given the investigational system's superior resolution and noise characteristics, observer results suggest that the high detective quantum efficiency of flat-panel digital radiography systems can be utilized to decrease the radiation dose/exposure to neonatal patients, although post-processing of the images remains to be optimized. The rapid availability of flat-panel images in portable imaging was found to be an added advantage for timely clinical decision-making.

Edaravone, a novel free radical scavenger, demonstrates neuroprotective effects by inhibiting vascular endothelial cell injury and ameliorating neuronal damage in ischemic brain models. The present study was undertaken to verify its therapeutic efficacy following acute ischemic stroke. We performed a multicenter, randomized, placebo-controlled, double-blind study on acute ischemic stroke patients commencing within 72 h of onset. Edaravone was infused at a dose of 30 mg, twice a day, for 14 days. At discharge within 3 months or at 3 months after onset, the functional outcome was evaluated using the modified Rankin Scale. Two hundred and fifty-two patients were initially enrolled. Of these, 125 were allocated to the edaravone group and 125 to the placebo group for analysis. Two patients were excluded because of subarachnoid hemorrhage and disseminated intravascular coagulation. A significant improvement in functional outcome was observed in the edaravone group as evaluated by the modified Rankin Scale (p = 0.0382). Edaravone represents a neuroprotective agent which is potentially useful for treating acute ischemic stroke, since it can exert significant effects on functional outcome as compared with placebo.

A simulation study was done to investigate a novel use of the Hotelling Observer. A two-layer model which included a Channelized Hotelling; Observer (CHO) followed by a Hotelling Observer (HO) was built to operate on three dimensional images containing multiple slices and multiple views similar to SPECT myocardial perfusion images. The simulated images were hearts with and without cold lesions, with noise and blur. For one lesion and each of 20 lesion locations, 1000 lesion-present and 1000 lesion-absent images were generated. These 40,000 images consisted a data set for that one lesion. Each image was reformatted into three rows, providing 10 adjacent short axis slices, 10 adjacent vertical long axis slices, and 10 adjacent horizontal long axis slices. The CHO was computed for each slice, giving 40,000 3/spl times/10 decision variable arrays. A HO was then applied on the decision variable arrays to obtain a multi-slice CHO-HO lesion detectability index. Three additional ensembles were generated for single slices through the lesion center, one short axis only, one vertical long axis only, and one horizontal long axis only. Applying the CHO to these ensembles gave lesion detectabilities for the short axis view, vertical long axis view, and horizontal long axis view respectively. An 10-fold cross validation was used to compute uncertainties in all detectabilities. Three data groups, total of 23 such sets with different lesion contrast, size, or shape were generated to compare the correlations between the performance of the multi-slice CHO-HO, the single-slice CHO, and human observers. The result suggests the ability of the multi-slice method to separate better these images into their correct classes as compared to the single-slice method, by combining information from multiple slices. The multi-slice method provides a single detectability scalar for studies in which the lesion could be present in multiple slices. It may be that a multi-slice CHO-HO model could more closely predict the performance of radiologists in tasks where the radiologist evaluates multi-slice and multi-view images.

To measure mean cerebral blood flow (CBF) in ischemic and nonischemic territories and in low-attenuation regions in patients with acute stroke by using deconvolution-derived hemodynamic imaging.Twelve patients with acute middle cerebral artery stroke and 12 control patients were examined by using single-section computed tomography (CT) perfusion scanning. Analysis was performed with a deconvolution-based algorithm. Comparisons of mean CBF, cerebral blood volume (CBV), and mean transit time (MTT) were determined between hemispheres in all patients and between low- and normal-attenuation regions in patients with acute stroke. Two independent readers examined the images for extent of visually apparent regional perfusion abnormalities. The data were compared with extent of final infarct in seven patients with acute stroke who underwent follow-up CT or magnetic resonance imaging.Significant decreases in CBF (-50%, P =.001) were found in the affected hemispheres of patients with acute stroke. Significant changes in CBV (-26%, P =.03) and MTT (+111%, P =.004) were also seen. Significant alterations in perfusion were also seen in low- compared with normal-attenuation areas. Pearson correlation between readers for extent of CBF abnormality was 0.94 (P =.001). Intraobserver variation was 8.9% for CBF abnormalities.Deconvolution analysis of CT perfusion data is a promising method for evaluation of cerebral hemodynamics in patients with acute stroke.

Purpose: The purpose of this work was to compare the extent of pseudoenhancement (artifactual increase in measured attenuation of a simple cyst after contrast medium administration) in a phantom model on single detector and multidetector helical CT scanners. Method: The phantom consisted of four water-filled spheres varying in size from 8 to 28 mm, suspended in an aqueous contrast medium bath. Iodine concentration in the bath was varied: 0, 6, 12. and 24 mg/ml corresponding to attenuation values of 0, +108, +180, and +300 HU. The phantom was scanned on single detector and multidetector helical CT scanners during the same session. Collimation (1, 3, and 5 mm) and pitch (1 and 1.5:1 single detector; 3:1 and 6:1, multidetector) were varied at each concentration. All scans were performed at 140 kVp and 170 mA. The region of interest was measured at the center of each sphere. The effects were analyzed using a linear regression model. Results: The degree of pseudoenhancement was more pronounced with increasing iodine concentration, decreasing cyst size, and wider collimation (all p = 0.0001). Pseudoenhancement was also more marked on the multidetector than the single detector scanner (p = 0.0001) ). At physiological levels of renal enhancement, the average pseudoenhancement was +18 HU for the single detector versus +23 HU for the multidetector scanner. Variation in pitch had no effect. Conclusion: Pseudoenhancement is greater on a multidetector than a single detector helical CT scanner and may exceed 20 HU at physiological levels of renal enhancement.

To determine if daclizumab, an interleukin-2 antagonist, reduced the severity of reperfusion edema in lung transplant recipients.Eighty-five patients who were to undergo 86 consecutive lung transplants were included; 43 (50%) received daclizumab in addition to conventional immunosuppression. Patients were assigned to one of the following groups: control, right allograft; control, left allograft; daclizumab treated, right allograft; daclizumab treated, left allograft. Radiographs obtained in the first 5 postoperative days were evaluated for degree of edema. Mean daily edema scores and curves for control and daclizumab-treated groups were compared. Differences in survival at 1, 3, 6, and 12 months after transplantation, days of mechanical ventilation, and the ratio of arterial oxygenation to inspired oxygen level at 1, 3, and 5 days after transplantation were also compared.Mean daily edema scores, edema curves, survival, days of mechanical ventilation, and ratio of arterial oxygenation to inspired oxygen level at 1 and 3 days after transplantation did not significantly differ between daclizumab-treated and control groups. A trend toward improved survival in the daclizumab-treated group was noted.Daclizumab had no effect on the radiographic or immediate clinical manifestations of reperfusion edema in lung transplant recipients. Additional follow-up is needed to determine if daclizumab offers any long-term benefit in terms of reduced rejection rates or survival.

To prospectively evaluate iliac angle and iliac length in a large number of normal fetuses and to identify factors that may influence these measurements.At antenatal ultrasonography (US) in 356 fetuses, the iliac angle and iliac length were measured at two axial levels (superior and inferior). In mixed linear models, the statistical significance and magnitude of effect on the measurement of iliac angle and iliac length were estimated for gestational age, fetal sex, maternal diabetes status, axial level, and spine position relative to the transducer.Statistically significant effects were found for gestational age, axial level, and spine orientation but not for fetal sex or maternal diabetes status. The iliac angle was found to decrease by 15.7 degrees from the superior to inferior portion of the pelvis, decrease by approximately 0.37 degrees /wk, and decrease by as much as 15.6 degrees when the spine is directed to the side. Iliac length was found to increase by 0.8 mm/wk from 13 weeks to term, decrease by 1.2 mm from the superior to the inferior portion of the pelvis, and increase by as much as 1.29 mm when the spine is not directly subjacent to the transducer.The axial level of measurement, gestational age, and spine orientation must be accounted for if these morphometric indexes are used to discriminate fetuses with and those without Down syndrome.

PURPOSE: To determine the effect of variability of common carotid arterial (CCA) velocities on velocity ratios used to assess internal carotid arterial (ICA) stenosis. MATERIALS AND METHODS: Doppler ultrasonographic (US) velocity measurements were obtained at three levels in the CCA and in the carotid bulb and ICA in all patients referred for carotid US between September 1996 and October 1997. Only ICAs (n = 98, in 57 patients) without ipsilateral CCA disease at angiography were analyzed. The range of CCA peak systolic velocities (PSVs) and end diastolic velocities (EDVs) and velocity ratios were calculated for each CCA measurement. For each ICA/CCA velocity ratio, receiver operating characteristic analysis was performed. RESULTS: CCA PSV and EDV ranges averaged 23.1 cm/sec ± 15.7 (SD) and 5.1 cm/sec ± 3.6, respectively. For a given side, the difference averaged 1.0 ± 1.3 for PSV ratios and 2.7 ± 6.9 for EDV ratios, depending on where CCA measurements were taken. By using a threshold of 60% stenosis as in...

Abstract: In this study, pain during mammography in women treated conservatively for breast cancer was examined. It studied pain intensity and its relation to a variety of demographic, medical, and pain coping variables as well as to objective measures of breast compression. Ninety-nine women, treated with lumpectomy (with or without radiation) and undergoing follow-up screening mammography, were asked about strategies they use to cope with everyday pain and then were asked to report pain experienced during the mammogram. Treated and untreated breasts were rated separately and compared with a sample of 125 control women with no history of breast cancer. Women reported significantly greater pain in the treated breast (41% greater than the untreated breast and 32% greater than the control group). There was no consistent relationship between mammography pain and pain coping. Average intensity of pain at last mammogram was the best predictor of pain in both breasts. Women treated conservatively for breast cancer experience significantly greater pain during mammography of their treated breast. Radiologists and technologists can identify women at risk for a painful mammogram by asking about the pain at last mammogram. By applying pain-reducing interventions, they might be able to make the mammography experience more tolerable for these women.

Our purpose was to perform a comprehensive review of our experience with compression of postcatheterization groin pseudoaneurysms.Two hundred eighty-one patients underwent 306 sonographically guided compression procedures on 297 groin pseudoaneurysms after femoral artery catheterization. The medical records, cardiac catheterization reports, and sonographic images were reviewed to determine patient demographics, type of catheterization procedure performed, sheath size, access site, interval from sheath removal to compression, anticoagulation status, pseudoaneurysm dimensions, complications, and follow-up information. Statistical analysis was performed using Pearson's chi-square and Kendall tau tests.The success rate for the initial compression attempt was 72.1%. Of the 83 failed compression attempts, 12 patients underwent a second attempt, of which seven attempts were successful. Therefore, counting both first and second attempts, the success rate was 74.4%. A strong negative correlation existed between anticoagulation status and success, with a 70% failure rate in patients with anticoagulated blood. Smaller pseudoaneurysm size was strongly correlated with success. Of the 83 failed cases, 49 ultimately underwent surgical repair. Eleven complications (3.6%) occurred, including three patients with rupture during compression. No deaths occurred as a result of compression repair.We conclude that sonographically guided pseudoaneurysm compression repair is an effective alternative to surgical repair, though nearly one third of compression attempts will fail and most of those patients will ultimately require surgery. The procedure is less effective when the patient's blood is anticoagulated and when the pseudoaneurysm is large. The procedure carries an overall complication rate of 3.6% and a risk for rupture of 1%.

The purpose of this study was to evaluate the stereotactic 14-gauge, vacuum-assisted biopsy technique in diagnosing noncalcified breast lesions. Stereotactic biopsy of 116 noncalcified breast lesions was performed with either 14-gauge, vacuum-assisted technique or multipass, automated large-core technique. The number of core samples and time required for each biopsy were compared. Outcome for each technique was compared based on recommendations after the mammographic-histologic review process. Results from surgical excision and mammographic follow-up were reviewed. The vacuum-assisted technique obtained more tissue cores per lesion than the automated gun technique, showed marginal decrease in number of repeat biopsies for discordant results, and required fewer short-term follow-up mammograms, although the difference did not achieve statistical significance. The vacuum-assisted technique can be used successfully to sample noncalcified breast masses, with marginal improvement over the automated gun technique.

Manual administration of IV contrast material results in unpredictable injection rates. Our purpose was to determine the effect of bolus tracking on overall abdominal helical CT scan quality, particularly on hepatic enhancement, in children with manually administered contrast media.We compared 33 abdominal helical CT scans of 29 children in whom bolus tracking was used with 22 CT scans of a control group of 21 children in whom bolus tracking was not used. All contrast material was administered by manual injection. Qualitative assessment was made of organ and vessel enhancement and overall scan appearance. Quantitative assessment using region-of-interest cursors was performed at three anatomic levels, and the results for the two groups of children were compared.Qualitative comparison of enhancement parameters between the bolus tracking group (number given first) and the control group (number given second) yielded the following: splenic artifact in 9% versus 23% (p = .24); inferior vena cava flow artifact in 3% versus 27% (p = .01); scanning during the nephrographic phase in 89% versus 59% (p = .02); and good quality grade in 79% versus 64% (p = .23). Significantly greater hepatic enhancement (as measured in mean Hounsfield units) was achieved in the bolus tracking group than in the control group at the superior (48.5 versus 28.6; p.001), middle (47.9 versus 32.3; p.001), and inferior (48.2 versus 36.5; p = .01) levels. Hepatic enhancement increased significantly from the superior to the inferior level in the control group (p.02), whereas enhancement was homogeneous in the bolus tracking group (p.50).Bolus tracking provides improved contrast enhancement, including significantly greater hepatic enhancement, during abdominal helical CT in children in whom the rate of injection of contrast material is unpredictable.

The purpose of this study was to evaluate triple-phase helical CT for detection of hepatic metastases from breast carcinoma.Breast cancer patients were studied prospectively with triple-phase helical CT in 300 consecutive examinations. Hepatic arterial-dominant and portal venous-dominant phase scans were initiated at 20 and 65 sec, respectively, after IV injection of 175 ml of iopamidol (30 mg/ml) at 5 ml/sec. Three independent observers each reviewed 200 cases of the portal venous-dominant phase for lesion number, conspicuity, and attenuation. Subsequently, portal venous-dominant phase images were reevaluated in conjunction with hepatic arterial-dominant phase or unenhanced images.Hepatic metastases were identified in 79 (26%) of 300 cases. Lesions detected on portal venous-dominant, hepatic arterial-dominant, and unenhanced images were as follows: observer 1, n = 198, 164, and 171; observer 2, n = 254, 233, and 233; and observer 3, n = 291, 270, and 276 (p.05). The mean total lesion count was 387, with more lesions detected on portal venous-dominant phase than on either hepatic arterial-dominant phase or unenhanced images (p.001 and p.0001, respectively). For individual observers, 10-26% of lesions were hypervascular on hepatic arterial-dominant phase images. Two to 4% of lesions were identified only on hepatic arterial-dominant phase or unenhanced images. However, in these few cases, the lesions either were false-positives or were seen in conjunction with additional metastases on portal venous-dominant images.Routine use of triple-phase CT in patients with breast carcinoma may not be warranted: Addition of the hepatic arterial-dominant phase or unenhanced images revealed few additional lesions in our group of 300 patients.

Risk-adjustment and provider profiling have become common terms as the medical profession attempts to measure quality and assess value in health care. One of the areas of care most thoroughly developed in this regard is quality assessment for coronary artery bypass grafting (CABG). Because in-hospital mortality following CABG has been studied extensively, risk-adjustment mechanisms are already being used in this area for provider profiling. This study compares eight different risk-adjustment methods as applied to a CABG surgery population of 28 providers. Five of the methods use an external risk-adjustment algorithm developed in an independent population, while the other three rely on an internally developed logistic model. The purposes of this study are to: (i) create a common metric by which to display the results of these various risk-adjustment methodologies with regard to dichotomous outcomes such as in-hospital mortality, and (ii) to compare how these risk-adjustment methods quantify the 'outlier' standing of providers. Section 2 describes the data, the external and internal risk-adjustment algorithms, and eight approaches to provider profiling. Section 3 then demonstrates the results of applying these methods on a data set specifically collected for quality improvement.

To compare the accuracy of virtual bronchoscopy (VB) with that of axial computed tomography (CT) in the assessment of bronchial anastomotic complications in lung transplant recipients.Twenty-seven bronchial anastomoses in 17 patients were evaluated with helical CT. Axial CT and VB images were evaluated for surface irregularity and the presence, length, and severity of stenosis. Findings were correlated with the results of fiberoptic bronchoscopy (FOB).There were 12 anastomotic stenoses at FOB. Pooled accuracy (among all four readers) of VB and axial CT for diagnosis of clinically relevant stenosis was 97% and 80%, respectively, at the right bronchial anastomoses and 92% and 75%, respectively, at the left bronchial anastomoses. Pooled accuracy of VB and Axial CT for stenosis length was 72% and 62%, respectively, at the right anastomoses and 81% and 69%, respectively, at the left anastomoses. These differences were not statistically significant. Both the VB and axial CT images showed surface irregularities when anastomotic infection (n = 2) or dehiscence (n = 1) was present but resulted in an overdiagnosis of mucosal abnormalities when anastomoses were normal.VB was slightly more accurate than axial CT for diagnosis of clinically relevant stenoses at bronchial anastomoses in lung transplant recipients. However, because VB is not 100% accurate and has no role in the diagnosis of infection or dehiscence, it probably will not replace FOB for assessment of bronchial anastomotic complications in this population.

The purpose of this study was to investigate the role of positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) in differentiating benign from malignant disease in patients with possible pancreatic malignancy.All patients with a possible diagnosis of pancreatic carcinoma based on CT or ERCP findings were eligible for inclusion in this prospective study. PET imaging of the abdomen was performed in 37 patients and was interpreted as positive if FDG activity in the pancreas exceeded background activity and as negative if activity was less than or equal to background activity. Semiquantitative analysis was performed by calculating a standardized uptake ratio. Studies were reviewed independently by two radiologists, and results were correlated with biopsy results and with CT and ERCP findings. Sensitivity and specificity of FDG PET for revealing pancreatic malignancy was determined.FDG activity in the pancreas was increased in 24 patients, and adenocarcinoma was diagnosed in 22 of these patients (92%). Two patients (8%) with increased activity had benign disease, including one patient with chronic pancreatitis who showed no evidence of tumor at laparotomy and one patient with a mucinous cystic tumor who showed no malignant features at laparotomy. FDG uptake was low or normal in 13 patients, 10 of whom (77%) had benign disease. FDG uptake was also low in three patients with adenocarcinoma, whose tumor size ranged from 2 to 4 cm in diameter. The mean standardized uptake ratio value for malignant disease was 5.1 (range, 1.0-10.1) and for benign disease was 1.9 (range, 0.0-5.8) (p.001). The sensitivity of FDG PET for revealing malignant disease in the pancreas was 88% and the specificity was 83%.FDG PET is a sensitive and specific noninvasive technique for the diagnosis of pancreatic malignancy.