Faculty Bibliography

The apical surface of mouse urothelium is covered by two-dimensional crystals (plaques) of uroplakin (UP) particles. To study uroplakin function, we ablated the mouse UPII gene. A comparison of the phenotypes of UPII- and UPIII-deficient mice yielded new insights into the mechanism of plaque formation and some fundamental features of urothelial differentiation. Although UPIII knockout yielded small plaques, UPII knockout abolished plaque formation, indicating that both uroplakin heterodimers (UPIa/II and UPIb/III or IIIb) are required for plaque assembly. Both knockouts had elevated UPIb gene expression, suggesting that this is a general response to defective plaque assembly. Both knockouts also had small superficial cells, suggesting that continued fusion of uroplakin-delivering vesicles with the apical surface may contribute to umbrella cell enlargement. Both knockouts experienced vesicoureteral reflux, hydronephrosis, renal dysfunction, and, in the offspring of some breeding pairs, renal failure and neonatal death. These results highlight the functional importance of uroplakins and establish uroplakin defects as a possible cause of major urinary tract anomalies and death

OBJECTIVE: The purpose of this study was to compare combined cine gradient-recalled echo MRI and MR angiography with conventional angiography in the evaluation of the pulmonary vascular supply in patients with pulmonary atresia, ventricular septal defect, and major aortopulmonary collateral arteries. MATERIALS AND METHODS: Eleven patients who underwent both MRI and conventional angiography were retrospectively reviewed. Contiguous 2D cine gradient-recalled echo images (TR range/TE, 30-80/4.8; flip angle, 20 degrees or 30 degrees ) and 3D MR angiographic images (TR range/TE range, 3.8-5.0/1.3-2.0; acquisition time, 13-32 sec) using gadopentetate meglumine (0.1-0.2 mmol/kg) were obtained. The presence, size, and course of the pulmonary arteries (main, right, left) and major aortopulmonary collateral arteries (>/= 5 mm) were determined. Presence of minor collateral arteries (< 5 mm) was also noted. Results were compared with findings at conventional angiography. RESULTS: MRI showed all main (n = 4) and branch (n = 17) pulmonary arteries found at conventional angiography and showed the pulmonary confluence in five of six cases. MRI showed all major aortic collaterals (n = 22) with a highly significant correlation between MRI and conventional angiography measurements (r = 0.84, p < 0.001 [95% confidence interval, -0.35 to 0.40]). One coronary artery collateral was not shown on MRI examination. At MRI, 12 of 14 major and four of seven minor brachiocephalic artery collaterals were shown. MRI showed more minor aortic collaterals than angiography (22 vs 18 vessels, respectively). CONCLUSION: Combined cine gradient-recalled echo MRI and MR angiography is a reliable method for imaging pulmonary vascular supply in patients with these disorders. Additional prospective studies comparing MRI and conventional angiography may determine whether routine preoperative conventional angiography is required

PURPOSE: To determine the accuracy of a focused computed tomographic (CT) technique with oral and intravenous contrast materials for the diagnosis of appendicitis. MATERIALS AND METHODS: Ninety-three abdominal-pelvic contrast material-enhanced CT scans obtained during 6 years in 54 girls and 39 boys (age range, 1-18 years) with right lower quadrant pain were retrospectively reviewed. The detected abnormal findings were recorded as being in the region above the upper pole of the right kidney, between the upper pole of the right kidney and the lower pole of the right kidney (RLP), or below the iliac crest. Sensitivity, specificity, and positive and negative predictive values were calculated. chi(2) analysis was performed to determine whether there were significant differences among patient groups according to region of detected disease. RESULTS: Fifty-five scans were abnormal: 38 showed appendicitis; and 17, other diseases. No scans, except two that showed pneumonia, had key findings above the RLP. Nineteen scans showed key findings between the RLP and the iliac crest. Thirty-three scans had diagnostic findings only below the iliac crest. The sensitivity (97%), specificity (93%), positive predictive value (90%), and negative predictive value (98%) of interpretation with all images for the diagnosis of appendicitis were the same as those of interpretation with only the focused images. CONCLUSION: CT performed to diagnose appendicitis can be limited to the region below the RLP

The epidermolysis bullosa-pyloric atresia-obstructive uropathy (EB-PA-OU) association is a rare, but well-described multisystem disease. While the prognosis at this time is still poor, an increasing number of patients are surviving to adolescence with aggressive care. It is important to understand this syndrome in order to anticipate medical complications and offer preventive strategies where possible. Prompt and expectant management of obstructive uropathy is crucial in these patients. Evidence of ureterovesicular obstruction may require bowel diversion, as excision of the obstructed ureterovesicular junction with reimplantation is often associated with a high risk of reobstruction. Many newborns succumb to sepsis or dehydration and electrolyte imbalance. Those infants who survive need close monitoring for the development of obstructive uropathy, failure to thrive, protein-losing enteropathy, respiratory compromise, and increased susceptibility to invasive infections. Once a clinical diagnosis is made, mutational analysis can confirm it and facilitate genetic counseling, as recurrence risks are 25% for this autosomal recessive condition. Mutational analysis enables direct genetic testing and accurate prenatal diagnosis. As more patients are studied, genotype/phenotype correlations may be possible

Nasoenteric feeding tubes are a safe and effective means for providing nutritional support to the critically ill patient. Serious complications have been reported, but usually are the result of an improper path of the tube during placement. The authors report a case of ampullary obstruction and jaundice caused by a nasoenteric feeding tube, presumably caused by coiling of the tube in the duodenum. This report represents the first such case in the literature

PURPOSE: Our goal was to describe the use of gadolinium-enhanced 3D MR angiography (MRA) in the diagnosis of interrupted aortic arch (IAA). METHOD: A review of our MR data base from a 1 year period yielded three patients (1 day, 8 days, and 16 years old) with IAA. All were referred for evaluation of aortic arch abnormalities, only one of whom had suspected IAA. Patients were imaged at 1.5 T with a 3D spoiled gradient echo pulse sequence (TR/TE 3.8-8/1.3-2.7 ms) following the administration of intravenous gadolinium chelates. Surgical correlation was available in all cases. RESULTS: In the patient with clinically suspected IAA, a previously unsuspected aberrant right subclavian artery was identified that was not seen on preoperative echocardiography. In another patient with a history of previous mediastinal surgery, IAA was diagnosed without concomitant cardiac anomalies, suggesting surgical ligation. In the remaining patient, IAA was detected as well as a patent truncus arteriosus. CONCLUSION: Gadolinium-enhanced 3D MRA may provide for a rapid diagnosis of IAA that may not be possible with other noninvasive modalities. The rapid acquisition time enables unstable pediatric patients to spend minimal time in the MR suite

BACKGROUND: Shone's complex is a series of four obstructive or potentially obstructive left-sided cardiac lesions (supravalvular mitral ring, parachute deformity of the mitral value, subaortic stenosis, and coarctation of the aorta). Both the complete form (all four lesions) and incomplete forms (less than four lesions) have been described. OBJECTIVE: To determine which abnormalities of Shone's complex could be characterized by MR. MATERIALS AND METHODS: MR examinations in three patients (one complete, two incomplete) were retrospectively reviewed. RESULTS: A supravalvular mitral ring, found at surgery in one patient, was not identified. Regurgitant and stenotic flow across the mitral valve, abnormal motion of the valve leaflets and abnormalities of the papillary muscles were identified. Individual chordal attachments were difficult to resolve. Narrowing in the subaortic region and abnormal flow from the subaortic region through the valve plane were demonstrated. A discrete subaortic diaphragm in one patient was not resolved. Both focal and diffuse types of coarctation of the aorta were well characterized. CONCLUSION: MR imaging is suited to evaluation of patients with Shone's complex. Individual chordal attachments and thin diaphragms of the mitral and aortic valves were difficult to resolve

Ruptured aneurysm of an aortic sinus of Valsalva is a rare cause of left-to-right shunting. We show how resonance imaging can be used to make the diagnosis. This technique can successfully characterize the shunt as well as determine the presence of associated anomalies, such as ventricular septation and aortic regurgitation. It may be the only study required prior to therapeutic intervention

OBJECTIVE. To determine an injection protocol for pediatric hepatic CT and to investigate the use of power injection. MATERIALS AND METHODS. Eighty-seven studies were prospectively performed using ioversol (320 mg iodine per cc) at 2 cc/kg. Three techniques were used: helical (1 s/slice); dynamic, non-breath-hold (5.5 s/slice); dynamic, breath-hold (10 s/slice) scans. The liver-scan time for each study was determined. Scan initiation ranged from 25 to 80 s. An injection duration (50-100 seconds) was selected. From the contrast volume (2 cc/kg x kg body wt) and injection duration, the injection rate (cc/s) was calculated for each patient. Each study was grouped by injection rate corrected for body weight (cc/kg/min) into: 1.2-1.5, 1.51-2.0, and 2.01-2.4. The aortic/liver attenuation curves were plotted for each group. RESULTS. Liver-scan time for helical studies was a mean of 26 s, for dynamic, non-breath-hold studies 75 s, dynamic breath-hold scans were 154 s. Injection rates of 1.2-1.5 cc/kg/min produced a scanning interval of 165 s. Injection rates of 1.51-2.0 cc/kg/min produced a scanning interval of 120 s. Injection rates of 2.01-2.4 cc/kg/min produced a scanning interval of 90 s. There was no increase in hepatic attenuation for the injection rates 2.01-2.4 cc/kg/min compared with 1.51-2.0 cc/kg/min. There was one complication related to injection through a central line. CONCLUSIONS. An injection protocol was determined for helical studies with injection rates of 1.7-2.0 cc/kg/min with initiation at 60 s; for dynamic, non-breath-hold studies with injection rates of 1.5-1.7 cc/kg/min with initiation at 50 s; and for dynamic breath-hold studies with injection rates of 1.2-1.5 cc/kg/min with initiation at 45 s. Power injection was used safely in our population