Sudha A. Anupindi

MR Imaging of the Abdomen and Pelvis in Infants, Children, and Adolescents

Recent developments in magnetic resonance (MR) imaging have profoundly changed the investigation of abdominal and pelvic disease in pediatrics. Motion reduction techniques, such periodically rotated overlapping parallel lines with enhanced reconstruction, or PROPELLER, have resulted in reliable imaging with quiet breathing. Faster imaging sequences minimize artifact and allow for more efficient studies. Diffusion-weighted imaging has become increasingly important in the evaluation of neoplastic disease, depicting disease with increased cellularity and helping to differentiate benign from malignant masses. MR enterography helps visualize intra- and extraluminal bowel pathologic conditions. MR cholangiopancreatography can depict congenital and acquired causes of pancreatic and biliary abnormalities. MR urography is an effective technique for a one-stop-shop evaluation of structural urinary tract abnormality and renal function. Three-dimensional acquisitions allow volumetric display of structures from multiple angles. Specialized techniques allow quantification of iron and fat in the viscera in children with hemolytic anemia and obesity, respectively. This article covers current techniques and strategies to perform and optimize MR imaging of the abdomen and pelvis in infants, children, and adolescents and describes important practical applications.

Pelvic MRI in children with Crohn disease and suspected perianal involvement

MRI is an important imaging tool in evaluation of adult and pediatric patients with Crohn disease. Pelvic MRI, in particular, has become the method of choice to evaluate for perianal fistulas and associated complications of Crohn disease. MRI can define the extent and location of perianal fistulas and abscesses, as well as provide critical information for operative management. In this pictorial essay, we describe useful MRI techniques for evaluation of perianal complications in pediatric patients with Crohn disease. We review pertinent anatomy and illustrate typical examples of perianal fistulas with and without abscess. We show one case of clinically suspected perianal fistula that was actually a pilonidal sinus.

Pancreatitis and the role of US, MRCP and ERCP.

Imaging plays a crucial role in the diagnosis of acute and chronic pancreatitis in children. Ultrasound (US) is the primary imaging modality. The US study can be improved by incorporating high resolution imaging, color Doppler, harmonic imaging and panorama view. Computer tomography (CT) is widely used for further evaluation. MR imaging in combination with MR cholangiopancreaticography (MRCP) is emerging as the modality of choice. It is non-invasive and radiation-free. It has high potential to replace endoscopic retrograde cholangiopancreaticography (ERCP), too. The latter is becoming more of an interventional tool. This review discusses the current status and comparative diagnostic potential of US, MRCP and ERCP.

Subpleural lung cysts in Down syndrome: prevalence and association with coexisting diagnoses.

BackgroundAlthough subpleural cysts are known to be associated with Down syndrome, their etiology and prevalence remains unknown.ObjectiveTo determine the prevalence of subpleural cysts in children with Down syndrome and the association with prematurity, congenital heart disease (CHD), extracorporeal membrane oxygenation (ECMO), and chronic ventilator support.Materials and methodsA review of the CT examinations of 25 children with Down syndrome was performed to determine the presence, location, and distribution of cysts along with associated abnormalities. Charts were reviewed and coexistent diagnoses and past treatments were recorded.ResultsThe prevalence of subpleural cysts was 36% with no significant association with CHD, ECMO, or chronic ventilator support. An association was found in the two children with a history of prematurity. The cysts were most commonly found in the anteromedial portion of the lung.ConclusionSubpleural cysts are common in Down syndrome and should not be confused with another pathological process. An association with prematurity was found, but the low number of children in this study makes the connection uncertain. The etiology remains unclear, but it has been hypothesized that the cysts are associated with lung hypoplasia.

Sonographic and radiographic imaging features of the neonate with necrotizing enterocolitis: correlating findings with outcomes

BackgroundAbdominal radiography is the reference standard in imaging neonates with necrotizing enterocolitis (NEC); however, ultrasound of the abdomen including bowel may be of value in this setting.ObjectiveTo correlate sonographic and radiographic findings with patient outcomes in NEC.Materials and methodsWe reviewed sonographic and radiographic exams, as well as clinical, pathological and laboratory records. Ultrasound images were reviewed for free intraperitoneal gas, peritoneal fluid, pneumatosis intestinalis, portal gas, bowel vascularity, bowel wall thickness and echogenicity, peristalsis and the presence of dilated bowel with anechoic contents. Contemporaneously acquired radiographs were reviewed for intraperitoneal gas, pneumatosis intestinalis, portal gas, the sentinel loop sign and gas pattern. Patients were categorized into two groups based on clinical outcome.ResultsForty-four neonates receiving 55 sonograms were included. Focal fluid collections, echogenic free fluid, increased bowel wall echogenicity and increased bowel wall thickness were statistically significant in predicting an unfavorable outcome. Other features approached significance in predicting poor outcomes: free peritoneal gas, pneumatosis intestinalis, aperistalsis, bowel wall thinning and absent bowel perfusion. Anechoic free peritoneal fluid predicted a good outcome. The sentinel loop sign on radiographs predicted an unfavorable outcome.ConclusionsAbdominal sonography and radiography in patients with NEC can help prognosticate the outcome.

Childhood Burkitt Lymphoma: Abdominal and Pelvic Imaging Findings

OBJECTIVE Burkitt lymphoma in children can be localized or disseminated and can involve various sites. Our objective is to review the clinical presentation and abdominopelvic imaging findings of Burkitt lymphoma in the pediatric population. CONCLUSION Numerous abdominal and pelvic imaging findings are seen in Burkitt lymphoma affecting the gastrointestinal tract and solid organs. Recognition of the common and uncommon imaging findings is essential in the diagnosis and treatment of patients with Burkitt lymphoma because prompt therapy is critical.

Diagnostic Performance of Whole-Body MRI as a Tool for Cancer Screening in Children With Genetic Cancer-Predisposing Conditions

OBJECTIVE Children with cancer-predisposing conditions are at increased risk to develop and die of cancer. Limited data exist on the utility of whole-body MRI as a cancer screening tool in children. In this study, we examined the diagnostic performance of whole-body MRI as a mechanism of tumor surveillance for children at increased genetic risk for cancer. MATERIALS AND METHODS Twenty-four children (six boys and 18 girls) with a mean age of 11.2 years (range, 2.1-18.2 years) underwent 50 unenhanced whole-body MRI examinations over a 5-year period. Scans were retrospectively reviewed and assessed for image quality; sequences performed; and the presence of osseous, soft-tissue, or solid organ abnormalities. Findings suggestive of a malignancy were stratified by risk as low (< 20% chance for cancer), moderate (20-80%), or high (> 80%). MRI findings were correlated with medical records, biopsy results, or additional follow-up imaging; biopsy and follow-up were considered as the reference standards. RESULTS Forty-eight of 50 (96%) examinations were of very good quality. Nine findings suspicious for malignancy were identified, including two high-risk, two moderate-risk, and five low-risk lesions. One high-risk lesion was proven by biopsy to be a papillary thyroid carcinoma, with the remaining lesions deemed nonmalignant. The sensitivity of whole-body MRI was 100%; specificity, 94%; positive predictive value, 25%; and negative predictive value (NPV), 100%. CONCLUSION Unenhanced whole-body MRI is safe and produces excellent images. The high sensitivity, specificity, and NPV make whole-body MRI a valuable cancer screening tool in children with a genetic predisposition for cancer.

Ultrasound of the bowel in children: how we do it

Advances in US like high-resolution transducers, harmonic imaging and panoramic modality have overcome some of the obstacles for sonography of the small and large bowel that existed in the past. In a number of centers, bowel US is an established routine method both in adults in children. Bowel US has the distinct advantages of being widely available, relatively cheap, free of radiation and easy to perform. In addition, US of the bowel demonstrates both mural and extramural pathological changes. Patients with inflammatory bowel disease have frequent imaging studies due to disease recurrences and need of follow-up after treatment. Thus this group of pediatric patients benefits most from an optimized and standardized bowel US. This review provides a comprehensive step-by-step approach how to perform US of the bowel in children with emphasis on imaging inflammatory bowel changes. It is meant to serve like a recipe and facilitate the routine performance of US of the bowel in children.

MR Imaging of the Bowel: Pediatric Applications

Magnetic resonance enterography with oral contrast administration using fast T2-weighted and fat saturated, contrast-enhanced T1-weighted sequences is the most common technique for bowel evaluation. The main indication for bowel MR imaging in children has been evaluation of inflammatory bowel diseases. A less common application is appendicitis. Other potential applications include evaluation of vascular malformations and transplanted bowel.

Tuberous sclerosis complex and renal angiomyolipoma: case report and review of the literature

A 5-year-old boy with a known diagnosis of tuberous sclerosis complex was found to have an enlarging renal mass on routine ultrasound. He was diagnosed with an angiomyolipoma (AML) and scheduled for close observation. Follow-up magnetic resonance imaging demonstrated the AML to be significantly enlarged and hypervascular. Selective arterial embolization of the tumor was performed, which resulted in an appropriate decrease in tumor size. Angiomyolipoma is a known and well-described complication of the tuberous sclerosis complex that is usually found among patients in their adolescent and adult years. The case presented here illustrates the need for early and repeated renal imaging of younger pediatric patients with tuberous sclerosis. Our experience adds to the literature on young pediatric patients requiring embolization for treatment of large renal angiomyolipomas.