Digital mammography: observer performance study of the effects of pixel size on the characterization of malignant and benign microcalcifications.

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 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. RESULTS: 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. 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.

Journal publications in radiologic education: a review of the literature, 1987-1997.

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 kappa statistic. A chi2 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.

Continuous quality improvement process to track lost radiographs and reduce losses.

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Congenital cystic adenomatoid malformation: impact of prenatal diagnosis and changing strategies in the treatment of the asymptomatic patient.

OBJECTIVE: This study was designed to assess the effect of prenatal sonographic diagnosis on the treatment of congenital cystic adenomatoid malformation of the lung. MATERIALS AND METHODS: 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. RESULTS: 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 (p < 0.001) 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;p < 0.001) and with a trend toward lower serious complication rate (3 patients without prenatal diagnosis versus 1 patient with it). CONCLUSION: 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.

Limitations of student evaluations of curriculum.

RATIONALE AND OBJECTIVES: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Current prognosis in necrotizing enterocolitis with portal vein gas.

OBJECTIVE: To investigate anecdotal reports that portal vein gas in necrotizing enterocolitis is no longer associated with a poor prognosis. PATIENTS AND METHODS: 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. RESULTS: 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. CONCLUSION: The children with portal vein gas on the initial abdominal film continue to have a guarded prognosis.

Value of case-of-the-week presentations on the radiology component of the Comprehensive Clinical Assessment examination.

RATIONALE AND OBJECTIVES: The Comprehensive Clinical Assessment (CCA) examination at the University of Michigan Medical School is a series of test stations through which the mastery of clinical skills is evaluated. The purpose of this study was to determine whether student performance on the radiology station improved in years when radiology faculty presented case-of-the-week unknowns to the 3rd-year students. MATERIALS AND METHODS: The authors compared four separate classes of medical students in examination years 1993, 1994, 1995, and 1996 by using the total CCA examination score, the radiology station score, and radiology station pass/fail rates. Radiology case-of-the-week presentations were given by the radiology faculty only in academic years 1993-1994 and 1994-1995 (examination years 1994 and 1995). RESULTS: The means and standard deviations of the radiology station scores for the examination years when case-of-the-week presentations were not given, 1993 and 1996, were 78.92 +/- 13.62 and 79.76 +/- 13.62, respectively. In the years case-of-the-week presentations were given, 1994 and 1995, the radiology station scores averaged 90.83 +/- 8.58 and 89.97 +/- 9.66, respectively (P < .001, global alpha = .05). Total CCA percentage correct scores were similar for all years studied. In 1993 and 1996, 7.6% and 5.3% of students, respectively, failed the radiology station. In 1994 and 1995, 0.4% and 0% of students, respectively, failed (P < .0001). CONCLUSION: Case-of-the-week presentations by radiology faculty increased 3rd-year students' basic radiologic knowledge as evidenced by increased scores on the radiology station of the CCA examination.

Vesicoureteral reflux in older children: concordance of US and voiding cystourethrographic findings.

PURPOSE: To determine if a negative renal sonogram is reliably predictive of the absence of vesicoureteral reflux at voiding cystourethrography (VCUG) in children aged 5 years or older. MATERIALS AND METHODS: Imaging studies in 70 children aged 5 years or older who underwent renal ultrasound (US) and VCUG on the same day were reviewed. These children had initially undergone evaluation because of a urinary tract infection. RESULTS: Five of 70 children had abnormal sonograms; two (40%) of the five had reflux at VCUG. One had mild pelvicalyceal dilatation, and one had a small kidney. The other three (without reflux) had a pelvic kidney, a calyceal diverticulum, or a renal stone. Of 65 children with a negative sonogram, 19 (29%) had reflux at VCUG; 46 (71%) did not. Altogether, of the 70 children, 21 had reflux, 19 (90%) of whom had no sonographic abnormality. CONCLUSION: Children with abnormal screening renal sonograms often have vesicoureteral reflux, but a normal sonogram does not reliably exclude the condition even in children aged 5 years or older. Therefore, VCUG must be performed even in older children, regardless of US findings, if clinical decisions are influenced by documentation of the presence of VUR.

Complications after gastric transposition in children.

BACKGROUND AND OBJECTIVE: Esophagogastrostomy with gastric transposition, a procedure for replacement of the esophagus in cases of esophageal atresia, is increasing in popularity among pediatric surgeons. This study was undertaken to document the differences between postoperative complications in children and those reported in adults. PATIENTS AND METHODS: The authors reviewed the medical records and radiologic images for details of complications in 6 children (5 boys and 1 girl) who underwent esophagogastrostomy with gastric transposition for esophageal atresia. Follow-up ranged from 18 months to 12 years. The observations were compared with complications in adults, as reported in the literature. RESULTS: The complications of gastric transposition were classified as early (up to 1 month after surgery) of late (more than 1 month after surgery). They included anastomotic leak (in 1 patient), hernia (in 1) and recurrent structure (in 3). In 1 patient mediastinal abscess developed secondary to esophageal perforation, which occurred during a dilation procedure for stricture. CONCLUSIONS: Postoperative complications of gastric transposition occur less commonly in children than in adults. Benign stricture, which may occur both early and late, is the most common problem.

Medical students' attitudes toward radiology: comparison of matriculating and graduating students.

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.

Use of abdominal ultrasonography to assess pediatric splenic trauma. Potential pitfalls in the diagnosis.

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.

Performance on the radiology component of a critical clinical skills examination.

RATIONALE AND OBJECTIVES: Clinical competence certification is now required in some specialties in medicine. A Comprehensive Clinical Assessment (CCA) was created to test mastery of critical skills by students at the end of the 3rd year of medical school. METHODS: The CCA is a series of stations that test skills the faculty consider important for all medical students (eg, breast examination, electrocardiogram reading, chest pain assessment, ophthalmology photographs). The radiology station was designed to evaluate imaging skills believed to be taught and learned in the core 3rd-year rotations. RESULTS: External measures (National Board Examinations, grade point average, and overall score) of clinical performance of the 608 medical students who completed the CCA examination between 1991 and 1993 were found to be correlated with the radiology station scores. CONCLUSION: The radiology station in the CCA examination is a reproducible measure of clinical performance.

Improvement of faculty teaching performance: efficacy of resident evaluations.

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.

Mycobacterium tuberculosis infection in immunocompetent children.

Objective. The purpose of this paper is to present our experience with Mycobacterium tuberculosis infections in immunocompetent children.Subjects and methods. Radiology, pathology, microbiology, and discharge records at two institutions identified the study population. Children who were immunocompromised and those with a positive skin test and no radiological or clinical evidence of active infection were excluded. Active mycobacterial infection was defined by a positive culture, biopsy, or a reactive purified protein-derivative skin test (PPD) with an appropriate clinical presentation and response to therapy 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 common sites of radiological involvement were the lungs (15 cases) and the hila (eight cases). Four patients had evidence of extrathoracic MTb infection. Three cases of miliary tuberculosis were identified, all in children less than 9 months of age. Conclusion. Although pulmonary and/or hilar disease remains the most common radiological presentation of childhood tuberculosis, the radiologist must be aware of the many radiological presentations of childhood Mycobacterium tuberculosis infection, and should have a high index of suspicion with the increasing incidence in both normal and immunocompromised children.

Enterocolitis associated with Hirschsprung's disease: a clinical-radiological characterization based on 168 patients.

The enterocolitis associated with Hirschsprung's disease (HD) has not been clearly characterized. This study was undertaken to analyze the clinical and radiological findings of Hirschsprung's enterocolitis (HEC) in 168 patients treated from July 1974 through October 1992. HEC occurred in 57 patients (33.9%), either preoperatively (13; 7.7%) or postoperatively (36; 21.4%). In eight patients (4.8%), it occurred pre- and postoperatively. The number of bouts of HEC per patient ranged from one to six (mean, 2.2). The major presenting features were abdominal distension (83%), explosive diarrhea (69%), vomiting (51%), fever (34%), lethargy (27%), rectal bleeding (5%), and colonic perforation (2.5%). There were no deaths directly related to HEC. The analysis of 150 plain x-rays of the abdomen, taken at the onset of HEC or in between bouts, showed that colonic dilatation was the most sensitive radiological finding (90% sensitivity), but it had poor specificity (24%). However, an intestinal cutoff sign (gaseous intestinal distension with abrupt cutoff at the level of the pelvic brim) was both sensitive (74%) and specific (86%) for HEC. Barium enema was of limited value in the diagnosis of HEC bouts because most of the radiographic findings persisted for prolonged periods after cessation of such bouts. The authors conclude that (1) HEC can be characterized as abdominal distension and explosive diarrhea associated with the intestinal cutoff sign and (2) the occurrence of explosive diarrhea in any patient with HD is suggestive of HEC, even in the absence of systemic symptoms, and should be treated to avoid the morbidity and potential mortality of HEC.

Bladder diverticula in children.

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.

Sonographic assessment of renal length in children: a reappraisal.

Ultrasonography (US) has largely replaced the intravenous urogram as the first modality for the evaluation of the kidneys in children suspected of having urinary tract abnormalities. Because many renal disorders are associated with changes in the sizes of the kidneys, normative standards for assessing renal size have been developed. These standards rely upon comparison of the renal lengths or calculated volumes or both, with various assessments of overall body size, including body surface area, weight, height, and chronological age. We discuss some of the limitations of US in assessing renal size in children. Practical recommendations are offered for optimizing the measurement and interpretation of sonographic renal sizes in children.

Enterocolitis following endorectal pull-through procedure in children with Hirschsprung's disease.

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.

Renal sonography is not a reliable screening examination for vesicoureteral reflux.

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.