Faculty Bibliography

PURPOSE: To retrospectively determine the accuracy of low-dose (20-mAs) computed tomography (CT) in the diagnosis of acute appendicitis in children by using a technique that enables the simulation of human CT scans acquired at a lower tube current given the image acquired at a standard dose. MATERIALS AND METHODS: Institutional review board approval was obtained, informed consent was not required, and the study was HIPAA compliant. The authors reviewed 100 standard-dose pediatric abdominal-pelvic CT scans (50 positive and 50 negative scans) obtained in 100 patients and corresponding simulated low-dose (20-mAs) scans. The standard-dose scans were obtained for evaluation in patients suspected of having appendicitis. Scans were reviewed in randomized order by four experienced pediatric radiologists. The patients with positive findings included 21 girls (mean age, 9.2 years) and 29 boys (mean age, 8.4 years). The patients with negative findings included 28 girls (mean age, 9.2 years) and 22 boys (mean age, 8.4 years). Simulation was achieved by adding noise patterns from repeated 20-mAs scans of a pediatric pelvis phantom to the original scans obtained with a standard tube current. Observers recorded their confidence in the diagnosis of appendicitis by using a six-point scale. Dose-related changes were analyzed with generalized estimating equations and the nonparametric sign test. RESULTS: There was a statistically significant (P < .001, sign test) decrease in both sensitivity and accuracy with a lower tube current, from 91.5% with the original tube current to 77% with the lower tube current. A low dose was the only statistically significant (P < .001) risk factor for a false-negative result. The specificity was unchanged at 94% for both the images obtained with the original tube current and the simulated low-dose images. The overall accuracy decreased from 92% with the original dose to 86% with the low dose. CONCLUSION: Preliminary findings indicate that it is feasible to optimize the CT dose used to evaluate appendicitis in children by using phantom-based computer simulations

We present an infant with macrocrania, who initially demonstrated prominent extra-axial fluid collections on sonography of the brain, compatible with benign infantile hydrocephalus (BIH). Because of increasing macrocrania, a follow-up sonogram of the brain was performed; it revealed progressive enlargement of the extra-axial spaces, which now had echogenic debris. Color Doppler US showed bridging veins traversing these extra-axial spaces, so it was initially thought that these spaces were subarachnoid in nature (positive cortical vein sign). However, an arachnoid membrane was identified superior to the cortex, and there was compression of true cortical vessels beneath this dural membrane. An MRI of the brain showed the extra-axial spaces to represent bilateral subdural hematomas. The pathogenesis of spontaneous development of the subdural hematomas, in the setting of BIH, is discussed. We also emphasize that visualizing traversing bridging veins through extra-axial spaces does not necessarily imply that these spaces are subarachnoid in origin

We present a case of a premature neonate who presented with anemia and persistent thrombocytopenia. The patient was ultimately diagnosed with disseminated tuberculosis. Initial sonographic evaluation of the abdomen revealed a heterogeneous but predominately hypoechoic spleen; there was subsequent evolution of a splenic abscess. The patient was treated medically with anti-tubercular drugs. Follow-up post-treatment sonograms of the spleen showed diminution of the abscess and the evolution of multiple calcifications compatible with calcified granulomas. This case is an unusual presentation of tuberculosis in an infant with splenic abscess associated with thrombocytopenia and anemia

Lipoblastomas are rare benign tumors of infancy that usually affect children younger than 3 years. Most lipoblastomas (70%) occur on the extremities. Lipoblastomas may mimic other infantile tumors, including hemangiomas, hibernomas, lipomas, and liposarcomas, and correct diagnosis is necessary to ensure appropriate treatment. Lipoblastomas fall under 2 discrete subtypes: well-circumscribed lipoblastomas and diffuse lipoblastomatosis. Both types present with firm, nontender masses of lobulated, well-circumscribed soft tissue. Histologically they can be highly vascularized with plexiform capillaries, often with an individual feeder artery to each lobule. Complete surgical removal is the recommended treatment. Only 2 cases of lipoblastomas of the cheek have been reported in the English-language literature. We present the case of a young child with a cheek lipoblastoma, emphasizing the importance of correct diagnosis and highlighting techniques used to provide suitable treatment

Metanephric adenoma (MA) is a renal tumor that is rarely found in children. We present a case of MA that was incidentally discovered in an 8-year-old child on computed tomography. We also review the literature regarding this lesion in the pediatric population. There are certain imaging features of MA that may suggest the diagnosis preoperatively. Metanephric adenoma is often hyperechoic on sonography, hyperdense on noncontrast computed tomography scans, and of low signal intensity on T1- and T2-weighted magnetic resonance images. Nephron sparring surgery has been performed in several cases. However, the distinction of MA from other metanephric lesions as well as from Wilms' tumor and papillary renal cell carcinoma may not be readily apparent at the time of surgery

We report the imaging findings of two recent cases of primary bacterial peritonitis in otherwise healthy children with a clinical presentation mimicking acute appendicitis. Primary bacterial peritonitis is rare in the absence of underlying systemic disease. Although it has been described in the pediatric literature, the imaging findings have not been described in the radiological literature to the best of our knowledge. With imaging playing an increasing role in the evaluation of appendicitis in children, it is important for the radiologist to be familiar with this inflammatory process

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

Hepatic hematomas in newborn infants are not frequently detected clinically, but are often found at perinatal autopsies. These hematomas of the liver are usually subcapsular in location. A variety of etiologies for such hematomas has been implicated, such as trauma, sepsis, and coagulopathies. We present a neonate who presented with jaundice and abdominal distention. Initial imaging studies revealed a large intraparenchymal lesion of the liver, which was at first thought to be suspicious for neoplasm; however, MRI showed the lesion to be hemorrhagic and follow-up sonographic studies showed total resolution of this lesion, compatible with hematoma. The intraparenchymal location and the idiopathic nature of this lesion distinguish this case from others previously reported

Sclerosing stromal tumor (SST) is a rare benign ovarian neoplasm of stromal origin with less than 100 cases reported in the literature. Unlike the other stromal tumors, thecomas and fibromas, which tend to occur in the fifth and sixth decades, sclerosing stromal tumors predominantly affect females in the second and third decades. Computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound findings have been described, but have not been reported previously in the pediatric literature. We present a case of SST of the ovary in a 10-year-old premenarchal female, the youngest patient to our knowledge reported in the literature, and describe the ultrasound and CT findings with pathologic correlation