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SARS-CoV-2 Spike protein is critical for virus infection via engagement of ACE2, and amino acid variation in Spike is increasingly appreciated. Given both vaccines and therapeutics are designed around Wuhan-1 Spike, this raises the theoretical possibility of virus escape, particularly in immunocompromised individuals where prolonged viral replication occurs. Here we report chronic SARS-CoV-2 with reduced sensitivity to neutralising antibodies in an immune suppressed individual treated with convalescent plasma, generating whole genome ultradeep sequences by both short and long read technologies over 23 time points spanning 101 days. Although little change was observed in the overall viral population structure following two courses of remdesivir over the first 57 days, N501Y in Spike was transiently detected at day 55 and V157L in RdRp emerged. However, following convalescent plasma we observed large, dynamic virus population shifts, with the emergence of a dominant viral strain bearing D796H in S2 and ΔH69/ΔV70 in the S1 N-terminal domain NTD of the Spike protein. As passively transferred serum antibodies diminished, viruses with the escape genotype diminished in frequency, before returning during a final, unsuccessful course of convalescent plasma. In vitro, the Spike escape double mutant bearing ΔH69/ΔV70 and D796H conferred decreased sensitivity to convalescent plasma, whilst maintaining infectivity similar to wild type. D796H appeared to be the main contributor to decreased susceptibility, but incurred an infectivity defect. The ΔH69/ΔV70 single mutant had two-fold higher infectivity compared to wild type and appeared to compensate for the reduced infectivity of D796H. Consistent with the observed mutations being outside the RBD, monoclonal antibodies targeting the RBD were not impacted by either or both mutations, but a non RBD binding monoclonal antibody was less potent against ΔH69/ΔV70 and the double mutant. These data reveal strong selection on SARS-CoV-2 during convalescent plasma therapy associated with emergence of viral variants with reduced susceptibility to neutralising antibodies.

Rationale and Objectives Current wire localization compression paddles provide a limited access window with no compression in this window. We describe a new compression paddle that addresses these issues and report on preliminary patient testing. Materials and Methods Four mechanical engineering students collaborated with a medical physicist, a radiographer, and two radiologists. Several concept designs were developed, one of which used a mesh surface. This went on to prototype development. After phantom testing, internal review board approval, US Food and Drug Administration waiver for nonsignificant risk device, and Medicare Part A exemption were obtained, the device was used in 10 patients going to wire localization for medical indications. Informed consent was obtained and a range of breast size was included. Wires were positioned from superior, lateral, and medial approach. Results A total of 10 wires were successfully positioned in nine patients. The one technical failure was due to inadequate access to the axillary region because of the single prototype size. The grid system provided accurate localization of suspicious findings. The mesh was not visible in digital mammograms so there was no interference. Conclusion The new paddle improves on currently available models. Advantages included lack of visual (on imaging) and technical interference from the compression mesh, and compression of the active window allowed localization of subtle findings. The large active area facilitated multiple wire placements within a single window. All localizations were easily performed on the initial image because of the large active window, obviating the need for acquisition of additional images and the associated additional radiation.

Rationale and Objectives To investigate the effect of a computer-aided diagnosis (CADx) system on radiologists' performance in discriminating malignant and benign masses on mammograms and three-dimensional (3D) ultrasound (US) images. Materials and Methods Our dataset contained mammograms and 3D US volumes from 67 women (median age, 51; range: 27–86) with 67 biopsy-proven breast masses (32 benign and 35 malignant). A CADx system was designed to automatically delineate the mass boundaries on mammograms and the US volumes, extract features, and merge the extracted features into a multi-modality malignancy score. Ten experienced readers (subspecialty academic breast imaging radiologists) first viewed the mammograms alone, and provided likelihood of malignancy (LM) ratings and Breast Imaging and Reporting System assessments. Subsequently, the reader viewed the US images with the mammograms, and provided LM and action category ratings. Finally, the CADx score was shown and the reader had the opportunity to revise the ratings. The LM ratings were analyzed using receiver-operating characteristic (ROC) methodology, and the action category ratings were used to determine the sensitivity and specificity of cancer diagnosis. Results Without CADx, readers' average area under the ROC curve, A z , was 0.93 (range, 0.86–0.96) for combined assessment of the mass on both the US volume and mammograms. With CADx, their average A z increased to 0.95 (range, 0.91–0.98), which was borderline significant ( P = .05). The average sensitivity of the readers increased from 98% to 99% with CADx, while the average specificity increased from 27% to 29%. The change in sensitivity with CADx did not achieve statistical significance for the individual radiologists, and the change in specificity was statistically significant for one of the radiologists. Conclusions A well-trained CADx system that combines features extracted from mammograms and US images may have the potential to improve radiologists' performance in distinguishing malignant from benign breast masses and making decisions about biopsies.

Rational and Objectives The increasing importance of imaging for both diagnosis and management in patient care has resulted in a demand for radiology services 7 days a week, 24 hours a day, especially in the emergency department (ED). We hypothesized the resident preliminary reports were better than generalist radiology interpretations, although inferior to subspecialty interpretations. Materials and Methods Total radiology volume through our Level I pediatric and adult academic trauma ED was obtained from the radiology information system. We conducted a literature search for error and discordant rates between radiologists of varying experience. For a 2-week prospective period, all preliminary reports generated by the residents and final interpretations were collected. Significant changes in the report were tabulated. Results The ED requested 72,886 imaging studies in 2004 (16% of the total radiology department volume). In a 2-week period, 12 of 1929 (0.6%) preliminary reports by residents were discordant to the final subspecialty dictation. In the 15 peer-reviewed publications documenting error rates in radiology, the error rate between American Board of Radiology (ABR)−certified radiologists is greater than that between residents and subspecialists in the literature and in our study. However, the perceived error rate by clinicians outside radiology is significantly higher. Conclusion Sixteen percent of the volume of imaging studies comes through the ED. The residents handle off-hours cases with a radiology-detected error rate below the error rate between ABR-certified radiologists. To decrease the perceived clinician-identified error rate, we need to change how academic radiology handles ED cases.

To retrospectively investigate the effect of using a custom-designed computer classifier on radiologists' sensitivity and specificity for discriminating malignant masses from benign masses on three-dimensional (3D) volumetric ultrasonographic (US) images, with histologic analysis serving as the reference standard.Informed consent and institutional review board approval were obtained. Our data set contained 3D US volumetric images obtained in 101 women (average age, 51 years; age range, 25-86 years) with 101 biopsy-proved breast masses (45 benign, 56 malignant). A computer algorithm was designed to automatically delineate mass boundaries and extract features on the basis of segmented mass shapes and margins. A computer classifier was used to merge features into a malignancy score. Five experienced radiologists participated as readers. Each radiologist read cases first without computer-aided diagnosis (CAD) and immediately thereafter with CAD. Observers' malignancy rating data were analyzed with the receiver operating characteristic (ROC) curve.Without CAD, the five radiologists had an average area under the ROC curve (A(z)) of 0.83 (range, 0.81-0.87). With CAD, the average A(z) increased significantly (P = .006) to 0.90 (range, 0.86-0.93). When a 2% likelihood of malignancy was used as the threshold for biopsy recommendation, the average sensitivity of radiologists increased from 96% to 98% with CAD, while the average specificity for this data set decreased from 22% to 19%. If a biopsy recommendation threshold could be chosen such that sensitivity would be maintained at 96%, specificity would increase to 45% with CAD.Use of a computer algorithm may improve radiologists' accuracy in distinguishing malignant from benign breast masses on 3D US volumetric images.

The purpose of our study was to investigate MR artifacts related to tissue marker clips used in breast imaging procedures.Breast phantoms were created using gelatin doped with gadolinium. Four commercially available tissue marker clips were evaluated. Clinical MR evaluation of all phantoms with 1.5-T gradient-recalled echo sequences was performed. Images were evaluated for size and character of the visible artifacts and graphically appreciable fat saturation inhomogeneities. Quantitative measurement of the local inhomogeneity in 3D parts per million maps was obtained as a function of distance from each tissue marker.All tissue marker clips caused signal void artifacts on non-fat-suppressed images that measured 2-6 times the clip diameter. The degree of fat suppression inhomogeneity was minor but clinically appreciable. The local clip-induced field inhomogeneity varied from 0.25 to greater than 4.0 PPM for the four clips. At 0.25 PPM, the zonal diameter of frequency shift varied from 6 mm to 44 mm.Artifacts caused by tissue marker clips could limit the sensitivity of MRI for detection and follow-up of breast cancer. The local effects on field inhomogeneity will affect local fat suppression and make spectroscopy data less reliable. These effects, though small, are measurable and vary among the different clips evaluated.

An observer performance study was conducted to evaluate the usefulness of assessing breast lesion characteristics with stereomammography. Stereoscopic image pairs of 158 breast biopsy tissue specimens were acquired with a GE Senographe 2000D full field digital mammography system using a 1.8 × magnification geometry. A phantom-shift method equivalent to a stereo shift angle of ± 3 ° relative to a central axis perpendicular to the detector was used. For each specimen, two pairs of stereo images were taken at approximately orthogonal orientations. The specimens contained either a mass, microcalcifications, both, or normal tissue. Based on pathological analysis, 39.9% of the specimens were found to contain malignancy. The digital specimen radiographs were displayed on a high resolution MegaScan CRT monitor driven by a DOME stereo display board using in-house developed software. Five MQSA radiologists participated as observers. Each observer read the 316 specimen stereo image pairs in a randomized order. For each case, the observer first read the monoscopic image and entered his/her confidence ratings on the presence of microcalcifications and/or masses, margin status, BI-RADS assessment, and the likelihood of malignancy. The corresponding stereoscopic images were then displayed on the same monitor and were viewed through stereoscopic LCD glasses. The observer was free to change the ratings in every category after stereoscopic reading. The ratings of the observers were analyzed by ROC methodology. For the 5 MQSA radiologists, the average A z value for estimation of the likelihood of malignancy of the lesions improved from 0.70 for monoscopic reading to 0.72 ( p = 0.04 ) after stereoscopic reading, and the average A z value for the presence of microcalcifications improved from 0.95 to 0.96 ( p = 0.02 ) . The A z value for the presence of masses improved from 0.80 to 0.82 after stereoscopic reading, but the difference fell short of statistical significance ( p = 0.08 ) . The visual assessment of margin clearance was found to have very low correlation with microscopic analysis with or without stereoscopic reading. This study demonstrates the potential of using stereomammography to improve the detection and characterization of mammographic lesions.

To evaluate the effects of computer-aided diagnosis (CAD) on radiologists' characterization of masses on serial mammograms.Two hundred fifty-three temporal image pairs (138 malignant and 115 benign) obtained from 96 patients who had masses on serial mammograms were evaluated. The temporal pairs were formed by matching masses of the same view from two different examinations. Eight radiologists and two breast imaging fellows assessed the temporal pairs with and without computer aid. The classification of accuracy was quantified by using the area under receiver operating characteristic curve (A(z)). The statistical significance of the difference in A(z) between the different reading conditions was estimated with the Dorfman-Berbaum-Metz method for analysis of multireader multicase data and with the Student paired t test for analysis of observer-specific paired data.The average A(z) for radiologists' estimates of the likelihood of malignancy was 0.79 without CAD and improved to 0.84 with CAD. The improvement was statistically significant (P =.005). The corresponding average partial area index was 0.25 without CAD and improved to 0.37 with CAD. The improvement was also statistically significant (P =.005). On the basis of Breast Imaging Reporting and Data System assessments, it was estimated that with CAD, each radiologist, on average, reduced 0.7% (0.8 of 115) of unnecessary biopsies and correctly recommended 5.7% (7.8 of 138) of additional biopsies.CAD based on analysis of interval changes can significantly increase radiologists' accuracy in classification of masses and thereby may be useful in improving correct biopsy recommendations.

We are developing an automated stereo spot mammography technique for improved imaging of suspicious dense regions within digital mammograms. The technique entails the acquisition of a full-field digital mammogram, automated detection of a suspicious dense region within that mammogram by a computer aided detection (CAD) program, and acquisition of a stereo pair of images with automated collimation to the suspicious region. The latter stereo spot image is obtained within seconds of the original full-field mammogram, without releasing the compression paddle. The spot image is viewed on a stereo video display. A critical element of this technique is the automated detection of suspicious regions for spot imaging. We performed an observer study to compare the suspicious regions selected by radiologists with those selected by a CAD program developed at the University of Michigan. True regions of interest (TROIs) were separately determined by one of the radiologists who reviewed the original mammograms, biopsy images, and histology results. We compared the radiologist and computer-selected regions of interest (ROIs) to the TROIs. Both the radiologists and the computer were allowed to select up to 3 regions in each of 200 images (mixture of 100 CC and 100 MLO views). We computed overlap indices (the overlap index is defined as the ratio of the area of intersection to the area of interest) to quantify the agreement between the selected regions in each image. The averages of the largest overlap indices per image for the 5 radiologist-to-computer comparisons were directly related to the average number of regions per image traced by the radiologists (about 50% for 1 region/image, 84% for 2 regions/image and 96% for 3 regions/image). The average of the overlap indices with all of the TROIs was 73% for CAD and 76.8%+/−10.0% for the radiologists. This study indicates that the CAD determined ROIs could potentially be useful for a screening technique that includes stereo spot mammographyimaging.

PURPOSE: To evaluate a noncommercial computer-aided detection (CAD) program for breast cancer detection with screening mammography. MATERIALS AND METHODS: A CAD program was developed for mammographic breast cancer detection. The program was applied to 2,389 patients’ screening mammograms at two geographically remote academic institutions (institutions A and B). Thirteen radiologists who specialized in breast imaging participated in this pilot study. For each case, the individual radiologist performed a prospective Breast Imaging Reporting and Data System (BI-RADS) assessment after viewing of the screening mammogram. Subsequently, the radiologist was shown CAD results and rendered a second BI-RADS assessment by using knowledge of both mammographic appearance and CAD results. Outcome analysis of results of examination in patients recalled for a repeat examination, of biopsy, and of 1-year follow-up examination was recorded. Correct detection with CAD included a computer-generated mark indicating a possible ...

The prevalence of pulmonary lymphoma in the pediatric age group is not documented in the literature.This study was designed to assess the prevalence of pulmonary parenchymal lymphoma in children with Hodgkin disease (HD), non-Hodgkin lymphoma (NHL) and post-transplant lymphoproliferative disorder (PTLD).A 10-year retrospective analysis of 161 lymphoma patients (62 girls and 99 boys), mean age of 12.4 years, was performed. The definition of pulmonary lymphoma excluded those with isolated pleural disease and/or mediastinal adenopathy.Eighty-two patients had HD, 65 had NHL, and 14 had PTLD. Overall prevalence of pulmonary parenchymal involvement was 13% (21/161), including 12% of patients with HD, 10% of patients with NHL, and 29% of patients with PTLD. CT findings included: pulmonary nodules (90%) or mass (38%); interstitial (9%) or alveolar (9%) disease; cavitation (9%); and pleural based mass (9%).Pulmonary parenchymal disease in our pediatric lymphoma population was more prevalent than expected (13%). This is significant for patient management. New pulmonary lesions in patients with known lymphoma should be regarded with suspicion. In the setting of immune suppression, pulmonary lesions treated as infection may actually represent lymphoma. Expeditious biopsy of lesions failing to respond promptly to antibiotic therapy should be considered.

RATIONALE AND OBJECTIVES: This study was performed to document the perceived decrease in fatty involution at screening mammography during the past decade and evaluate the influence of hormone replacement therapy (HRT). MATERIALS AND METHODS: In December 1996, the mammograms of 261 consecutive screening patients with a comparison study obtained 5 years earlier were evaluated, and their breasts were categorized according to Breast Imaging Reporting and Data System categories for breast density. The women, aged 50-59 years, included 119 who had been receiving HRT for 0.25-15 years (mean, 3 years). From the files, 261 age-matched screening mammograms from 1986 were obtained; these patients also had comparison mammograms from 1981. Analysis of variance was used to determine differences between the 1980s group, the 1990s group receiving HRT, and the 1990s group not receiving HRT. Scheffe tests were used for post hoc comparisons. Stepwise regression analysis was used to evaluate the relative influence of age, decade, score of the first mammogram, and HRT. RESULTS: Breast density for the 1991 mammograms did not differ significantly from that in 1981 (P < .05). Initial breast density was the best predictor of final breast density in both decades (P < .001), regardless of HRT status. The change in breast density (toward fatty) over the 5-year interval in the 1980s (mean, 0.48) was significantly greater than that in both 1990s groups (mean for HRT group, 0.11; no HRT, 0.30; P < .05). CONCLUSION: These results confirm that breast density at screening mammography in the 1990s did not decrease with age at the same rate as in the 1980s, even in patients not receiving HRT.

Rationale and Objectives The authors performed this study to evaluate the effects of pixel size on the characterization of mammographic microcalcifications by radiologists. Materials and Methods Two-view mammograms of 112 microcalcification clusters were digitized with a laser scanner at a pixel size of 35 μm. Images with pixel sizes of 70, 105, and 140 μm were derived from the 35-μm–pixel size images by averaging neighboring pixels. The malignancy or benignity of the microcalcifications had been determined with findings at biopsy or 2-year follow-up. Region-of-interest images containing the microcalcifications were printed with a laser imager. Seven radiologists participated in a receiver operating characteristic (ROC) study to estimate the likelihood of malignancy. The classification accuracy was quantified with the area under the ROC curve ( A z ). The statistical significance of the differences in the A z values for different pixel sizes was estimated with the Dorfman-Berbaum-Metz method and the Student paired t test. The variance components were analyzed with a bootstrap method. Results The higher-resolution images did not result in better classification; the average A z with a pixel size of 35 μm was lower than that with pixel sizes of 70 and 105 μm. The differences in A z between different pixel sizes did not achieve statistical significance. Conclusion Pixel sizes in the range studied do not have a strong effect on radiologists' accuracy in the characterization of microcalcifications. The low specificity of the image features of microcalcifications and the large interobserver and intraobserver variabilities may have prevented small advantages in image resolution from being observed.

Rationale and Objectives This study was designed to analyze articles on radiologic education quantitatively and qualitatively, comparing those published in 1987–1997 with those published in 1966–1986. Materials and Methods An initial literature search used four major databases to identify and retrieve articles related to radiologic education. Additional articles were identified through manual cross-checking of references from the original articles. All articles were reviewed by two radiologists as to type of article (editorial, expository, survey, correlational, or experimental, including preexperimental, quasi-experimental, or true experimental), statistics used (inferential or descriptive), educational emphasis (medical student, resident, postgraduate, or other), and topic of article (philosophical or political, technology, program evaluation, program description, examinations, or career decisions). Interrater agreement was estimated by means of the κ statistic. A χ2 test for independence was used to assess whether the relative distribution of articles was similar for the two periods. Results More articles per year were published in 1987–1997 (n = 12.6, P < .01) compared with 1966–1986 (n = 9.2). Articles pertinent to radiologic resident education predominated (50.7% vs 29.9% in the prior study, P < .01). In both periods, most articles were expository (37.7% vs 49.5%), and the most common topic was program description (34% vs 35%). Editorials decreased from 35.5% to 18.1%. Experimental studies accounted for 12.3%, increased from 8.7%. The fastest-growing topic of study was technology (30.4% vs 17.5%, P < .01). Conclusion The increased number of articles addressing radiologic education is encouraging. Although the percentage of experimental studies increased slightly in this period, there is still little empirical research in radiologic education.

This study was designed to assess the effect of prenatal sonographic diagnosis on the treatment of congenital cystic adenomatoid malformation of the lung.The medical records of 27 patients with pathologically proven congenital cystic adenomatoid malformations were retrospectively reviewed. Patients were divided into four groups based on mode of presentation: with or without abnormal findings on prenatal sonography and with or without symptoms at birth. Age at diagnosis, age at surgical intervention, complications, and length of hospital stay were recorded for each group.Twenty-seven patients with 31 proven congenital cystic adenomatoid malformations were included. Eleven patients underwent prenatal sonography establishing the diagnosis (6 asymptomatic at birth, 5 symptomatic), and 16 did not have a prenatal diagnosis (10 asymptomatic at birth, 6 symptomatic). In the symptomatic populations, prenatal diagnosis had no impact on age at surgery, length of stay, or surgical complication rate (p = 0.78-0.83). In the asymptomatic population, prenatal diagnosis allowed early diagnosis (p0.001) and resection in the asymptomatic period. It was also associated with a shorter length of stay at the time of surgical resection (mean time, 4.2 days for patients with prenatal diagnosis versus 12.9 days for those without it;p0.001) and with a trend toward lower serious complication rate (3 patients without prenatal diagnosis versus 1 patient with it).Prenatal sonography provides the radiologist a means to identify congenital cystic adenomatoid malformations in a population of infants who are asymptomatic at birth. Surgical intervention in the asymptomatic infant is associated with a shorter length of stay, a trend toward fewer complications, and decreased medical cost compared with intervening after symptoms develop.

The large brain of modern cetaceans has engendered much hypothesizing about both the intelligence of cetaceans (dolphins, whales, and porpoises) and the factors related to the evolution of such large brains. Despite much interest in cetacean brain evolution, until recently there have been few estimates of brain mass and/or brain–body weight ratios in fossil cetaceans. In the present study, computed tomography (CT) was used to visualize and estimate endocranial volume, as well as to calculate level of encephalization, for two fully aquatic mid-late Eocene archaeocete species, Dorudon atrox and Zygorhiza kochii. The specific objective was to address more accurately and more conclusively the question of whether relative brain size in fully aquatic archaeocetes was greater than that of their hypothesized sister taxon Mesonychia. The findings suggest that there was no increase in encephalization between Mesonychia and these archaeocete species.

The purpose of our study was to document the hidden costs in achieving high recall patient compliance from an off-site screening mammography program.This study was approved by our institutional review board. At our institution, no patient was placed in final BI-RADS assessment category 3, 4, or 5 without a diagnostic study. Each incomplete study, in addition to the formal report, was flagged on the day sheet, letters were sent to the referring physician and patient, and an incomplete computer code was added. Working from the day sheets, a clerk contacted the patient by telephone within 2 working days to schedule the diagnostic study. Diagnostic slots were purposely left open to accommodate these cases. An ongoing computer tickler file of incomplete codes provided a further check. A time study of clerical performance with recalled patients was measured prospectively for 100 consecutive cases.For the years 2002-2004, 4,025 (13%) of 30,286 screening patients were recalled for diagnostic mammography. After an average of 2.2 telephone calls per patient, (3.64 minutes of clerical time), 3,977 of 4,005 patients returned for a diagnostic study. Forty-eight of 4,025 initially noncompliant patients received an average of six telephone calls (4.7 minutes) and a registered letter. One of the 28 initially noncompliant patients went on to biopsy that revealed a breast cancer. Patient compliance was 4,005 (99.5%) of 4,025. The additional cost for this program was $4,724 divided by 30,286 screening patients, or 16 cents per screening patient.The radiology department assumed responsibility for contacting patients who needed recall for additional diagnostic imaging. Using strict documentation of the incomplete breast imaging evaluations, computer checks, clerical support, and prompt scheduling, we achieved 99.5% compliance. The additional cost was small, 16 cents per screening patient.

Rationale and Objectives: To determine graduating medical students' perceptions of radiology and to document changes in their perceptions since they entered medical school. Materials and Methods: A survey questionnaire was distributed to 213 graduating students. Questions were similar to those answered by the same group of students as they entered medical school nearly 4 years earlier. Results: The survey was anonymously completed by 140 students. Seventy percent of students changed their choice of medical specialty since entering medical school. Factors with a major or important influence on specialty choice included intellectual excitement (96%), high patient contact (86%), opportunity for a good family life (72%), and regular hours (57%). Radiology was perceived to be a well-paid (89%), “high-tech” (86%) specialty with a healthy lifestyle (82%), regular hours (99%), and good family life (92%), but it was not perceived to offer high patient contact (1%) and was intellectually exciting to only 33% of students. This perception was unchanged from freshman year. Conclusions: This 4-year longitudinal study of a medical student class documents surprisingly little change in the perception of radiology throughout medical school. High patient contact and intellectual excitement, both factors of major or important influence on specialty choice, were thought to be lacking in radiology.

OBJECTIVE: The purpose of this study was to evaluate the accuracy of abdominal ultrasonography (US) for screening and grading pediatric splenic injury. SUMMARY BACKGROUND DATA: The use of abdominal US has increased rapidly as a method of evaluating organ damage after blunt abdominal trauma. Despite US's increasing use, little is known about its accuracy in children with splenic injury. METHODS: Children (N = 32) suffering blunt abdominal trauma who were diagnosed with splenic injury by computerized tomography (CT) scan prospectively were enlisted in this study. Degree of splenic injury was evaluated by both CT and US. The ultrasounds were evaluated by an initial reading as well as by a radiologist who was blinded as to the results of the CT. RESULTS: Twelve (38%) of the 32 splenic injuries found on CT were missed completely on the initial reading of the US. When the ultrasounds were graded in a blinded fashion, 10 (31%) of the splenic lacerations were missed and 17 (53%) were downgraded. Seven (22%) of the 32 splenic fractures were not associated with any free intraperitoneal fluid on the CT scan. CONCLUSIONS: This study has shown that US has a low level of sensitivity (62% to 78%) in detecting splenic injury and downgrades the degree of injury in the majority of cases. Reliance on free intraperitoneal fluid may be inaccurate because not all patients with splenic injury have free intra-abdominal fluid. Based on these findings, US may be of limited use in the initial assessment, management, and follow-up of pediatric splenic trauma.

Objective. The purpose of this paper is to present our experi- ence with Mycobacterium tubercu- losis infections in immunocompe- tent children. Subjects and methods. Radiology, pathology, microbiology, and dis- charge records at two institutions identified the study population. Children who were immunocom- promised and those with a positive skin test and no radiological or clin- ical evidence of active infection were excluded. Active mycobacte- rial infection was defined by a posi- tive culture, biopsy, or a reactive purified protein-derivative skin test (PPD) with an appropriate clinical presentation and response to ther- apy and/or known exposure to an adult with active tuberculosis. Results. There were 22 children in whom Mycobacterium tuberculosis (MTb) was identified. Fourteen of the patients with MTb were 5 years of age or younger. The most com- mon sites of radiological involve- ment were the lungs (15 cases) and the hila (eight cases). Four patients had evidence of extrathoracic MTb infection. Three cases of miliary tu- berculosis were identified, all in children less than 9 months of age. Conclusion. Although pulmonary and/or hilar disease remains the most common radiological presen- tation of childhood tuberculosis, the radiologist must be aware of the many radiological presentations of childhood Mycobacterium tubercu- losis infection, and should have a high index of suspicion with the in- creasing incidence in both normal and immunocompromise d children.

Rationale and Objectives. We assessed the effects on the perceived quality of faculty teaching of a resident evaluation form that solicits specific comments on faculty strengths and weaknesses. Methods. An evaluation form was devised that rated faculty on a scale of 1–10 in teaching conference quality, availability, efficiency, and teaching. The form requested constructive comments on faculty strengths and weaknesses. The forms were completed anonymously by residents at all levels. Individual results and means for the department were tabulated and provided to each faculty member in a personal interview. Change in performance was assessed by comparing faculty evaluation scores for 2 consecutive years. Results. The mean faculty scores for teaching conference quality, availability, efficiency, and teaching increased from 7.8, 7.9, 7.9, and 7.7 to 8.1, 8.3, 8.3, and 8.1 in each of the respective areas. The scores of the faculty members who initially received the 10 lowest scores rose to an even greater extent (from 6.2, 6.2, 6.0, and 6.0 to 6.8, 7.4, 7.3, and 6.8 in each of the respective areas), whereas the scores of the faculty members who initially received the 10 highest scores remained relatively constant. Conclusion. The perceived quality of certain focused aspects of resident teaching can be modified by use of resident evaluations that solicit specific suggestions for improvement. With appropriate feedback, this is an effective tool for improving the teaching performance of radiology department faculty, particularly those considered to be the weakest teachers.

We conducted a prospective study to define normal renal pelvic size in children.Institutional Review Board approved consent was obtained to perform renal ultrasound during excretory urography (IVP) scheduled for medical management. Mean patient age (17 females, 11 males) was 5.2 years. Renal ultrasound was conducted concurrent with 10-minute IVP.Fifty kidneys were imaged with 51 collecting systems. IVP defined 44 collecting systems as normal. Mean anteroposterior pelvic diameter on sonography for these 44 systems was 3.3 mm. One normal collecting system on IVP had a diameter greater than 10 mm on ultrasound (14 mm). No sonographic caliceal dilatation was seen in any kidney appearing normal on IVP. The 7 dilated systems on IVP had a mean ultrasound diameter of 17.1 mm. Two dilated collecting systems smaller than 10 mm in diameter on sonography had caliceal distention on ultrasound.Normal renal pelvis threshold diameter was 10 mm in asymptomatic children. We recommend further evaluation in children with caliceal dilatation and/or dilatation of the anteroposterior renal pelvis greater than 10 mm. Using these criteria, no system appearing abnormal on IVP would have been missed.

Anterior gastric fundoplication (AGF) has been performed at the University of Michigan since 1988. To objectively evaluate the long-term efficacy of the AGF, the authors performed a study of children who had undergone AGF between June 1988 and June 1990 (n = 46). Six of them died of unrelated causes. Twenty-two consented to follow-up evaluation that included parental interview, physical examination, upper gastrointestinal series (UGI), 24-hour esophageal pH probe monitoring (EpH), and a liquid-phase gastric emptying study. Twenty patients (74%) remained asymptomatic, and only one child required reoperation. Four asymptomatic patients exhibited gastroesophageal reflux (GER) by UGI, and three others by EpH. Three children were noted to have delayed gastric emptying. These results compare favorably with data previously reported from this institution of a 5-year follow-up of children after Nissen fundoplication. There is a trend toward improved efficacy (87% v 74%; P = .12), decreased reoperation rate (4% v 14%; P = .11), and less severe complications. The present study shows that AGF is effective treatment for GER when evaluated by objective studies and is comparable in therapeutic efficacy and safety to the Nissen fundoplication.

A retrospective analysis of 493 infants and children was performed to determine the reliability of renal sonography for identifying vesicoureteral reflux. Sonography was done in all cases within 8 hours of a voiding cystourethrogram. Vesicoureteral reflux was documented in 272 of 986 kidneys on voiding cystourethrography and there were 201 refluxing kidneys with normal ultrasound (25 with grade I reflux, 119 with grade II, 50 with grade III, 6 with grade IV and 1 with grade V). In 71 of the refluxing kidneys the ultrasound was abnormal due to pelvicaliceal dilatation in 45, a duplication anomaly in 6 and renal fossae abnormality in 20. Of the kidneys with vesicoureteral reflux 74% were sonographically normal. Sonography was not sufficiently sensitive or specific for detecting vesicoureteral reflux, since 28% of the missed refluxing kidneys had grade III or higher reflux.

Eight children forming an uncommon subgroup of renal obstructive dysplasia are presented. Each child had a nonfunctioning dysplastic kidney with a single collecting system with ectopic ureteral insertion and/or ureterocele. Five of the children had classic multicystic dysplastic kidneys, one had the hydronephrotic type of multicystic dysplastic kidney and two had hypoplastic kidneys. Other significant medical problems in 5 of the 8 children (63%) included VACTERL association, congenital heart disease and other genitourinary malformations. Unlike some children with unilateral multicystic dysplastic kidney, this subgroup of children has an increased risk of infection. They must be correctly identified on imaging so that tailored clinical management decisions can be made and associated anomalies detected.

Nine of twelve family members from three generations were affected by an inherited form of cervical vertebral dysplasia. All of the affected people had an abnormality of the first cervical vertebra. Some also had defects of the axis and caudad to it. The mode of transmission of the disorder is autosomal dominant, with apparently complete penetrance and variable expressivity. Two patients had symptoms. One had a passively correctable tilt of the head, with an associated audible clunk and hypoplasia of the left superior facet of the second cervical vertebra. This patient had no local symptoms, neurological involvement, or muscle spasm. In the other patient, suboccipital pain developed. Radiographs revealed an anterior atlanto-occipital dislocation. The symptoms resolved after reduction and arthrodesis. Because of the apparently complete penetrance of this disorder, physicians caring for patients who have this type of congenital malformation of the cervical spine should consider examination of closely related members of the family. Clinical findings such as tilting of the head, torticollis, or limitation of cervical motion suggest that additional evaluation should be done. The examination should include lateral radiographs of the cervical spine in flexion and extension. Three-dimensional computed-tomography reformatting was helpful in demonstrating the complex cervical anatomy in our patients. Patients who have recognized abnormalities should be followed and should be re-examined whenever local or neurological symptoms develop. A magnetic resonance image of the spine in flexion and extension was valuable for identification of the potentially disastrous situation of impending damage to the cord in patients who had instability and evolving symptoms.

The Ilizarov method for limb lengthening is rapidly gaining popularity in North America. Use of this new technique has necessitated modifications in radiographic protocol. Initial imaging problems gained from our experience with twenty children are detailed including accurate centering for the plain films, correcting for magnification to accurately measure the distraction gap and the expected radiographic appearance of the regenerate bone. Ultrasonography has potential value in accurately measuring the distraction gap and in imaging the new bone prior to radiographic appearance. Since overly fast distraction inhibits bone formation and overly slow distraction leads to premature consolidation, ultrasound may serve a useful role in the qualitative evaluation of new bone formation in Ilizarov limb lengthening, enabling the orthopedic surgeon to tailor the distraction rate to the particular child.

Objective: To describe the long-term changes in the traumatized spleen following conservative man- agement in pediatric patients. Methods: Between 1991 and 1997, 92 children were imaged with splenic trauma. The study population includes the 25 boys and 11 girls with follow-up computed tomography (CT) imaging at our institution. The follow-up CT studies were evalu- ated to determine the evolution of splenic injury. Re- sults: On initial CT there were 6 grade I, 12 grade II, 9 grade III, and 9 grade IV-V splenic injuries. In follow- up 11 spleens were normal (30 %), including at least one in each grade of severity of injury. Splenic abnor- malities were identified on follow-up in 25 children. These findings comprised clefts in 8 children, small cysts in 4, and devascularized segments involving less than 1c m 3 in 6, 1-2 cm 3 in 2, and 2-4 cm 3 in 5 children. Con- clusions: All grades of splenic injury can resolve com- pletely on subsequent CT imaging. In this series 30 % of patients had a normal follow-up CT. The most com- mon persistent abnormalities included clefts and devas- cularized areas less than 4 cm 3 .

To assess the ability of contrast enhanced computed tomography (CECT) to detect active hemorrhage and other vascular injuries in chest, abdominal, and pelvic trauma patients, using angiographic findings and need for intervention as paired gold standards.We obtained approval from the Institutional review board for a retrospective search of the radiology information system: seeking trauma patients undergoing angiography within 24 hours of CECT for chest, abdominal, or pelvic injuries. CECT protocol was standard trauma CT, not specialized for CT angiography. Angiographic techniques varied with indication. Clinical and imaging reports and selected radiologic studies were reviewed, but the original dictated report was the interpretive standard. We used Fisher's exact test for statistical analysis.During the 30-month study period, 466 patients underwent emergent interventional radiologic procedures. Of those, 418 were excluded for nontrauma indications or neuroangiographic procedures. Fourty-eight patients (33 male, 15 female, average age 43.4) thus constituted the study population in whom we evaluated 63 traumatic injuries. CT findings had statistically significant associations (p0.0001) with both angiographic evidence of active hemorrhage and the need for intervention, which were tabulated separately. CT had 94.1% sensitivity and 97.6% negative predictive value (NPV) for detection of active hemorrhage, and 92.6% sensitivity and 91.2% NPV for predicting need for surgical or endovascular intervention.CECT findings correlate strongly with angiographic findings, though sensitivity remains imperfect. However, when CT is used in the context of other clinical features, particularly hemodynamic instability, it may enable clinicians to reserve emergent angiography for those patients in whom emergent intervention is planned.

To retrospectively evaluate effects of computer-aided diagnosis (CAD) involving an interval change classifier (which uses interval change information extracted from prior and current mammograms and estimates a malignancy rating) on radiologists' accuracy in characterizing masses on two-view serial mammograms as malignant or benign.The data collection protocol had institutional review board approval. Patient informed consent was waived for this HIPAA-compliant retrospective study. Ninety temporal pairs of two-view serial mammograms (depicting 47 malignant and 43 benign biopsy-proved masses) were obtained from 68 patient files and were digitized. Biopsy was the reference standard. Eight Mammography Quality Standards Act of 1992-accredited radiologists and two breast imaging fellows assessed digitized two-view temporal pairs (in preselected regions of interest only) by estimating likelihood of malignancy and Breast Imaging Reporting and Data System (BI-RADS) category without and with CAD. Observers' rating data were analyzed with Dorfman-Berbaum-Metz (DBM) multireader multicase method. Statistical significance of differences was estimated with the DBM method and Student two-tailed paired t test.Average area under the receiver operating characteristic curve for likelihood of malignancy across the 10 observers was 0.83 (range, 0.74-0.88) without CAD and improved to 0.87 (range, 0.80-0.92) with CAD (P.05). The average partial area index above a sensitivity of 0.90 for likelihood of malignancy was 0.35 (range, 0.13-0.54) without CAD and 0.49 (range, 0.18-0.73) with CAD--a nonsignificant improvement (P = .11). For BI-RADS assessment, it was estimated that with CAD, six radiologists would correctly recommend additional biopsies for malignant masses (range, 4.3%-10.6%) and five would correctly recommend reduction of biopsy (ie, fewer biopsies) for benign masses (range, 2.3%-9.3%). However, five radiologists would incorrectly recommend additional biopsy for benign masses (range, 2.3%-14.0%), and one would incorrectly recommend reduction of biopsy (4.3%).CAD involving interval change analysis of preselected regions of interest can significantly improve radiologists' accuracy in classifying masses on digitized screen-film mammograms as malignant or benign.

The increasing importance of imaging for both diagnosis and management in patient care has resulted in a demand for radiology services 7 days a week, 24 hours a day, especially in the emergency department (ED). We hypothesized the resident preliminary reports were better than generalist radiology interpretations, although inferior to subspecialty interpretations.Total radiology volume through our Level I pediatric and adult academic trauma ED was obtained from the radiology information system. We conducted a literature search for error and discordant rates between radiologists of varying experience. For a 2-week prospective period, all preliminary reports generated by the residents and final interpretations were collected. Significant changes in the report were tabulated.The ED requested 72,886 imaging studies in 2004 (16% of the total radiology department volume). In a 2-week period, 12 of 1929 (0.6%) preliminary reports by residents were discordant to the final subspecialty dictation. In the 15 peer-reviewed publications documenting error rates in radiology, the error rate between American Board of Radiology (ABR)-certified radiologists is greater than that between residents and subspecialists in the literature and in our study. However, the perceived error rate by clinicians outside radiology is significantly higher.Sixteen percent of the volume of imaging studies comes through the ED. The residents handle off-hours cases with a radiology-detected error rate below the error rate between ABR-certified radiologists. To decrease the perceived clinician-identified error rate, we need to change how academic radiology handles ED cases.

An observer performance study was conducted to evaluate the usefulness of assessing breast lesion characteristics with stereomammography. Stereoscopic image pairs of 158 breast biopsy tissue specimens were acquired with a GE Senographe 2000D full field digital mammography system using a 1.8x magnification geometry. A phantom-shift method equivalent to a stereo shift angle of +/- 3 degrees relative to a central axis perpendicular to the detector was used. For each specimen, two pairs of stereo images were taken at approximately orthogonal orientations. The specimens contained either a mass, microcalcifications, both, or normal tissue. Based on pathological analysis, 39.9% of the specimens were found to contain malignancy. The digital specimen radiographs were displayed on a high resolution MegaScan CRT monitor driven by a DOME stereo display board using in-house developed software. Five MQSA radiologists participated as observers. Each observer read the 316 specimen stereo image pairs in a randomized order. For each case, the observer first read the monoscopic image and entered his/her confidence ratings on the presence of microcalcifications and/or masses, margin status, BI-RADS assessment, and the likelihood of malignancy. The corresponding stereoscopic images were then displayed on the same monitor and were viewed through stereoscopic LCD glasses. The observer was free to change the ratings in every category after stereoscopic reading. The ratings of the observers were analyzed by ROC methodology. For the 5 MQSA radiologists, the average Az value for estimation of the likelihood of malignancy of the lesions improved from 0.70 for monoscopic reading to 0.72 (p=0.04) after stereoscopic reading, and the average Az value for the presence of microcalcifications improved from 0.95 to 0.96 (p=0.02). The Az value for the presence of masses improved from 0.80 to 0.82 after stereoscopic reading, but the difference fell short of statistical significance (p=0.08). The visual assessment of margin clearance was found to have very low correlation with microscopic analysis with or without stereoscopic reading. This study demonstrates the potential of using stereomammography to improve the detection and characterization of mammographic lesions.

We have previously evaluated the effects of computer-aided diagnosis (CAD) on radiologists' characterization of malignant and benign breast masses in single-view serial mammograms. In this study, we conducted observer performance experiments with ROC methodology in which the radiologists read the serial mammograms in two-views (CC and MLO) without and with CAD. 47 temporal pairs of two-view serial mammograms (27 malignant and 20 benign) containing masses were chosen from 39 patient files and digitized. The corresponding masses on each temporal pair were analyzed by the CAD program. For this data set, the computer classifier achieved a test Az value of 0.90. Five MQSA radiologists assessed the two-view temporal pairs and provided estimates of the likelihood of malignancy without and then with CAD. For the five radiologists, the average Az was 0.81 (range: 0.72-0.88) without CAD and improved to 0.88 (range: 0.86-0.90) with CAD. The improvement was statistically significant (p=0.038). In comparison, the test Az value of the computer classifier for single view analysis was 0.87. The average Az of the radiologists for reading the single view temporal pairs without CAD was 0.78 (range: 0.73-0.83) and was improved significantly (p=0.002) to 0.84 (range: 0.77-0.88) with CAD. CAD using interval change analysis can significantly improve radiologists' accuracy in classification of masses. Classification based on information from two-views is more accurate than that based on single view for both the radiologists and the computer classifier. CAD can further improve radiologists' performance even in two-view reading.

We are developing computer vision techniques for the characterization of breast masses as malignant or benign on radiologic examinations. In this study, we investigated the computerized characterization of breast masses on three-dimensional (3-D) ultrasound (US) volumetric images. We developed 2-D and 3-D active contour models for automated segmentation of the mass volumes. The effect of the initialization method of the active contour on the robustness of the iterative segmentation method was studied by varying the contour used for its initialization. For a given segmentation, texture and morphological features were automatically extracted from the segmented masses and their margins. Stepwise discriminant analysis with the leave-one-out method was used to select effective features for the classification task and to combine these features into a malignancy score. The classification accuracy was evaluated using the area Az under the receiver operating characteristic (ROC) curve, as well as the partial area index Az(0.9), defined as the relative area under the ROC curve above a sensitivity threshold of 0.9. For the purpose of comparison with the computer classifier, four experienced breast radiologists provided malignancy ratings for the 3-D US masses. Our dataset consisted of 3-D US volumes of 102 biopsied masses (46 benign, 56 malignant). The classifiers based on 2-D and 3-D segmentation methods achieved test Az values of 0.87+/-0.03 and 0.92+/-0.03, respectively. The difference in the Az values of the two computer classifiers did not achieve statistical significance. The Az values of the four radiologists ranged between 0.84 and 0.92. The difference between the computer's Az value and that of any of the four radiologists did not achieve statistical significance either. However, the computer's Az(0.9) value was significantly higher than that of three of the four radiologists. Our results indicate that an automated and effective computer classifier can be designed for differentiating malignant and benign breast masses on 3-D US volumes. The accuracy of the classifier designed in this study was similar to that of experienced breast radiologists.

An ROC study was conducted to evaluate the usefulness of assessing breast lesion characteristics with stereomammography. Stereoscopic image pairs of 158 breast biopsy tissue specimens were acquired with a GE digital mammography system. Two stereo image pairs were taken at 1.8X magnification geometry and at approximately orthogonal orientations for each specimen. Display software was developed for a high resolution MegaScan CRT monitor driven by a DOME stereo display board. The specimens contained either a mass, microcalcifications, both, or normal tissue. About 40% of the specimens were found to contain malignancy by pathological analysis. Five MQSA radiologists participated in the observer performance experiment. The two views of each specimen were read independently and were separated by a large number of other specimen images to reduce any effects of memorization. Each observer read 316 specimen images in a systematically randomized order. The observer first read the monoscopic image and entered his/her assessment in terms of the confidence ratings on the presence of microcalcifications and/or masses, margin clearance, BI-RADS assessment, and the likelihood of malignancy. The corresponding stereoscopic images were then displayed on the same monitor and were viewed through stereoscopic LCD glasses. The observer was free to change the ratings in every category after stereoscopic reading. The ratings of the observers were analyzed by ROC methodology. For the 5 MQSA radiologists, the average Az value for estimation of the likelihood of malignancy of the lesions improved from 0.70 for monoscopic viewing to 0.72 (p

We conducted an observer performance study using receiver operating characteristic (ROC) methodology to evaluate the effects of computer-aided diagnosis (CAD) on radiologists’ performance for characterization of masses on serial mammograms. The automated CAD system, previously developed in our laboratory, can classify masses as malignant or benign based on interval change information on serial mammograms. In this study, 126 temporal image pairs (73 malignant and 53 benign) from 52 patients containing masses on serial mammograms were used. The corresponding masses on each temporal pair were identified by an experienced radiologist and automatically segmented by the CAD program. Morphological, texture, and spiculation features of the mass on the current and the prior mammograms were extracted. The individual features and the difference between the corresponding current and prior features formed a multidimensional feature space. A subset of the most effective features that contained the current, prior, and interval change information was selected by a stepwise procedure and used as input predictor variables to a linear discriminant classifier in a leave-one-case-out training and testing resampling scheme. The linear discriminant classifier estimated the relative likelihood of malignancy of each mass. The classifier achieved a test Az value of 0.87. For the ROC study, 4 MQSA radiologists and 1 breast imaging fellow assessed the masses on the temporal pairs and provided estimates of the likelihood of malignancy without and with CAD. The average Az value for the likelihood of malignancy estimated by the radiologists was 0.79 without CAD and improved to 0.87 with CAD. The improvement was statistically significant (p=0.0003). This preliminary result indicated that CAD using interval change analysis can significantly improve radiologists’ accuracy in classification of masses and thereby may increase the positive predictive value of mammography.

The enterocolitis following a pull-through in Hirschsprung's disease can be life-threatening and difficult to distinguish clinically from gastroenteritis and post-operative complications. We reviewed retrospectively the abdominal radiographs in our series to identify specific radiographic characteristics of this syndrome in this population. A total of 55 episodes of enterocolitis with an abdominal series at presentation were located in the files of 43 patients following pull-through surgery for Hirschsprung's disease. There were 15 abdominal series with other complications of Hirschsprung's disease and surgery (seven cases of small bowel obstruction, one of fistula, one of abscess, six of severe constipation) and 71 surveillance follow-up studies. Radiographs were evaluated for bowel dilatation, air-fluid levels, intestinal cut-off sign, speculation, and pneumatosis. The intestinal cut-off sign with two or more air-fluid levels had sensitivity of 68% and specificity of 83%, with a positive predictive value of 0.71 and overall accuracy of 77%. Our review of enterocolitis following pull-through in children with Hirschsprung's disease concludes that the constellation of an intestinal cut-off sign and at least two air-fluid levels on the abdominal series strongly suggests the diagnosis.

PURPOSE: The frequency, number, and underlying associations of bladder diverticula were studied in a pediatric population. MATERIALS AND METHODS: Eighty-five children with bladder diverticula (31 girls and 54 boys) were retrospectively identified in a pediatric genitourinary data base of 5,084 children. RESULTS: Primary bladder diverticula were seen in 20 children with vesicoureteral reflux and 14 children without reflux. Fifty-one of the 85 children (60%) had associated neurogenic dysfunction of the bladder (n = 26), outlet obstruction (n = 14), or a syndrome (n = 9) or were postoperative (n = 2). A single child of the 26 with multiple bladder diverticula had no associated condition. CONCLUSION: In this population, bladder diverticula were found in 1.7% of the children. The presence of more than one diverticulum on a side was usually associated with neurogenic dysfunction of the bladder, bladder outlet obstruction, or syndromes such as Williams, Menkes, prune-belly, or Ehlers-Danlos type 9 syndromes.

To emphasize the utility of computed tomography (CT) in the diagnosis of pyelonephritis in children with complex comorbidities.We retrospectively reviewed the CT imaging studies and medical records of 12 patients (8 girls, 4 boys; aged 2-18 years [mean 8.6 yr]) who did not have a classic presentation of pyelonephritis but were diagnosed by CT. All patients had fever at clinical presentation, and pyelonephritis was not suspected in any case. Two children had negative urine cultures before imaging.All 12 patients had wedge-shaped areas of hypoattenuation on CT, 7 bilaterally; 10 had enlargement of an involved kidney; 5 had perinephric fat stranding; and 3 had focal abscesses.Although classic and uncomplicated pyelonephritis is a clinical diagnosis that does not require imaging, sometimes the presentation may be equivocal and the diagnosis unsuspected. Pyelonephritis is one of several potential sources of fever that can be simultaneously evaluated using CT. Using. CT, the unsuspected diagnosis of pyelonephritis can be made and therapy initiated before the urine culture is positive.

The referring physicians at our institution used the enema as a diagnostic test in children with suspected intussusception.To determine the change in rate of positive enema findings performed for suspected intussusception with the intervention of screening ultrasound (US).Since October 1995, 224 children (mean age 2.2 years) with suspected intussusception were referred for enema examination. In January 2001, US was introduced as a screening test for intussusception. Enemas were performed for all children with positive US findings and were offered for those with negative US findings if clinical suspicion persisted.Before 2001, 184 children underwent enema with intussusception documented in 40 (22%). Since January 2001, 40 children have been seen with suspected intussusception (12/40 positive or 30%). Two directly underwent enema (1/2 positive); 38 children underwent US. In 12 of 38 children, the US finding was positive, and an intussusception was found at enema examination in 11 of 12. In 26 cases, the US finding was negative. Seven of the 26 children with a negative sonogram finding had an enema, which was also negative. Nineteen enemas were canceled. With a screening US, the positive rate for enemas is now 58% (11/19). We know of no case of intussusception missed at US.Screening US has decreased unnecessary enemas for clinically suspected intussusception, increasing positive findings from 22% to 58%. This has in turn reduced children's exposure to radiation.

To describe a quality improvement process that was initiated in a Department of Radiology to reduce the number of incomplete or "lost" imaging studies and decrease the time from the initiation of an imaging study to printing of the final report.Incomplete cases were defined as those imaging studies that did not have a signed final report more than 3 days and less than 90 days after imaging. A computer program was written to generate a monthly incomplete case list from the radiology information system database; each step in the process, from patient arrival to final report printing, was analyzed and a list of root causes (for the incomplete cases) was developed. Short- and long-term interventions were introduced and the effects were monitored from 1992-1999.Problems were identified at each step in the process. Although some of the root causes originated outside the authority of the Department of Radiology, interventions we implemented within the department reduced the incomplete list by 72%, from a high of 2.8% of all imaging examinations to less than 0.8%. Continual monitoring of the problem is necessary to maintain this level.The number of incomplete or "lost" imaging studies can be decreased using a continuous quality improvement process. This leads to improved patient care and increased revenue.

The authors performed this study to evaluate the effects of pixel size on the characterization of mammographic microcalcifications by radiologists.Two-view mammograms of 112 microcalcification clusters were digitized with a laser scanner at a pixel size of 35 microm. Images with pixel sizes of 70, 105, and 140 microm were derived from the 35-microm-pixel size images by averaging neighboring pixels. The malignancy or benignity of the microcalcifications had been determined with findings at biopsy or 2-year follow-up. Region-of-interest images containing the microcalcifications were printed with a laser imager. Seven radiologists participated in a receiver operating characteristic (ROC) study to estimate the likelihood of malignancy. The classification accuracy was quantified with the area under the ROC curve (Az). The statistical significance of the differences in the Az values for different pixel sizes was estimated with the Dorfman-Berbaum-Metz method and the Student paired t test. The variance components were analyzed with a bootstrap method.The higher-resolution images did not result in better classification; the average Az with a pixel size of 35 microm was lower than that with pixel sizes of 70 and 105 microm. The differences in Az between different pixel sizes did not achieve statistical significance.Pixel sizes in the range studied do not have a strong effect on radiologists' accuracy in the characterization of microcalcifications. The low specificity of the image features of microcalcifications and the large interobserver and intraobserver variabilities may have prevented small advantages in image resolution from being observed.

This study was designed to analyze articles on radiologic education quantitatively and qualitatively, comparing those published in 1987-1997 with those published in 1966-1986.An initial literature search used four major databases to identify and retrieve articles related to radiologic education. Additional articles were identified through manual cross-checking of references from the original articles. All articles were reviewed by two radiologists as to type of article (editorial, expository, survey, correlational, or experimental, including preexperimental, quasi-experimental, or true experimental), statistics used (inferential or descriptive), educational emphasis (medical student, resident, postgraduate, or other), and topic of article (philosophical or political, technology, program evaluation, program description, examinations, or career decisions). Interrater agreement was estimated by means of the kappa statistic. A chi2 test for independence was used to assess whether the relative distribution of articles was similar for the two periods.More articles per year were published in 1987-1997 (n = 12.6, P.01) compared with 1966-1986 (n = 9.2). Articles pertinent to radiologic resident education predominated (50.7% vs 29.9% in the prior study, P.01). In both periods, most articles were expository (37.7% vs 49.5%), and the most common topic was program description (34% vs 35%). Editorials decreased from 35.5% to 18.1%. Experimental studies accounted for 12.3%, increased from 8.7%. The fastest-growing topic of study was technology (30.4% vs 17.5%, P.01).The increased number of articles addressing radiologic education is encouraging. Although the percentage of experimental studies increased slightly in this period, there is still little empirical research in radiologic education.

Medical student surveys are used extensively in the development and modification of curriculum. The purpose of this study was to look at medical student surveys of a radiology lecture series, evaluating the accuracy of student perceptions of learning and factors affecting them.After a "Case of the Week" lecture series, 156 3rd-year medical students returned a survey evaluating the experience with 10 questions on a four-point scale (1 = disagree, 4 = agree very much) and took a clinical competency assessment (CCA) examination with a radiology substation. Survey responses were compared with actual examination performance, analyzed for how overall learning was characterized in specific educational objectives, and evaluated for factors affecting perceived learning.The mean response for perceived CCA examination preparedness was 1.83. The mean radiology station test score was 90.43%. Correlations between student perception of learning and the scoring of focused learning objectives ranged from 0.33 to 0.48 (P.01). Students responding 1 to items assessing perceived lecture organization, stimulation to read, and interest in the field of radiology had mean scores for perception of overall learning of 2.09-2.44 and mean scores for recommendation of course continuation of 1.68-2.46. Students responding 4 had means of 3.25-3.81 and 3.06-4.0, respectively.Student perceptions of the value of curriculum were inaccurate compared with external measures of performance, and students poorly related their general impressions to specific learning objectives. Perceived lecture organization, stimulation to read, and interest in radiology as a specialty affected perceived overall learning and perceived value of the lecture series.

A receiver operating characteristic (ROC) experiment was conducted to evaluate the effects of pixel size on the characterization of mammographic microcalcifications. Digital mammograms were obtained by digitizing screen-film mammograms with a laser film scanner. One hundred twelve two-view mammograms with biopsy-proven microcalcifications were digitized at a pixel size of 35 micrometer X 35 micrometer. A region of interest (ROI) containing the microcalcifications was extracted from each image. ROI images with pixel sizes of 70 micrometers, 105 micrometers, and 140 micrometers were derived from the ROI of 35 micrometer pixel size by averaging 2 X 2, 3 X 3, and 4 X 4 neighboring pixels, respectively. The ROI images were printed on film with a laser imager. Seven MQSA-approved radiologists participated as observers. The likelihood of malignancy of the microcalcifications was rated on a 10-point confidence rating scale and analyzed with ROC methodology. The classification accuracy was quantified by the area, Az, under the ROC curve. The statistical significance of the differences in the Az values for different pixel sizes was estimated with the Dorfman-Berbaum-Metz (DBM) method for multi-reader, multi-case ROC data. It was found that five of the seven radiologists demonstrated a higher classification accuracy with the 70 micrometer or 105 micrometer images. The average Az also showed a higher classification accuracy in the range of 70 to 105 micrometer pixel size. However, the differences in A(subscript z/ between different pixel sizes did not achieve statistical significance. The low specificity of image features of microcalcifications an the large interobserver and intraobserver variabilities may have contributed to the relatively weak dependence of classification accuracy on pixel size.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

To investigate anecdotal reports that portal vein gas in necrotizing enterocolitis is no longer associated with a poor prognosis.Twelve cases of neonatal necrotizing enterocolitis with portal vein gas from 1988 to 1994 were identified retrospectively from the radiology dictation system in a large university hospital.Two distinct groups of patients with portal vein gas in necrotizing enterocolitis were identified. In 3 of the 12 children, portal vein gas was identified on abdominal films after the diagnosis of necrotizing enterocolitis. These infants had no serious sequelae. By contrast, in 8 of the 9 infants with portal vein gas seen on the initial film at presentation, emergent surgery was required. Four of these infants died from complications of necrotizing enterocolitis and 2 died from sepsis related to total parenteral nutrition. The remaining 2 children have short bowel syndrome, 1 is dependent on total parenteral nutrition and 1 requires continuous gastrostomy tube feedings.The children with portal vein gas on the initial abdominal film continue to have a guarded prognosis.