A normal ovary in an abnormal location: A case of torsion.

The clinical and radiologic diagnosis of adnexal torsion is challenging. The patient's history, physical examination, and laboratory evaluation may overlap significantly with other causes of abdominal pain. Ultrasound is the most common radiologic tool to assess for torsion, and the imaging findings can be equally equivocal. We present a case of adnexal torsion in an 18-year-old emergency room patient with abdominal pain, diagnosed by ultrasound based solely on an abnormal medial position of the ovary-a finding that has been only rarely mentioned in the literature, and never in isolation.

Imaging of pediatric renal transplants and their complications: a pictorial review.

Renal transplantation is the treatment of choice for end-stage renal disease in children. As a technically demanding surgery with complex medical management, it is associated with a number of complications. Anatomic imaging including ultrasonography with color and spectral Doppler and functional assessment with renal perfusion scintigraphy are complementary for the detection and characterization of posttransplant complications. Complications can be characterized by the time of appearance after transplantation (immediate, early, or late) or the anatomic site of origin (perinephric, vascular, urologic, or renal parenchymal). Perinephric fluid collections include hematomas and seromas, abscesses, lymphoceles, and urinomas. Noninfected collections frequently resolve spontaneously but should be monitored to exclude progression. Vascular complications are more prevalent in pediatric patients because of the small vessel caliber and include vascular thrombosis and stenosis. Arteriovenous fistulas and pseudoaneurysms can complicate biopsy and are typically transient. Common urologic complications include urine leak and urinary tract obstruction. Renal perfusion scintigraphy can be invaluable in elucidating the nature of such complications. Renal parenchymal abnormalities include acute tubular necrosis, rejection, and toxic effects of medication. Imaging features of renal parenchymal abnormalities can overlap, and the primary role of imaging is to exclude alternative causes of renal dysfunction. Renal and nonrenal mass lesions are more common in immunosuppressed patients after transplantation. Familiarity with the normal imaging appearance of the renal allograft and the appearances of common complications facilitates accurate diagnosis and timely treatment, with the ultimate goal of increasing graft survival. This goal is particularly crucial in children, given their greater number of projected life years.

FDG PET of the brain in pediatric patients: imaging spectrum with MR imaging correlation.

Positron emission tomography (PET) of the brain is an important problem-solving tool in pediatric neuroimaging, neurology, and neurosurgery. Fluorine 18 fluorodeoxyglucose (FDG) PET or dual-modality PET and computed tomographic (CT) imaging (PET/CT), with magnetic resonance (MR) imaging correlation, can be used to evaluate childhood epilepsy and pediatric brain tumors, areas in which PET adds value in patient management. FDG PET has been widely used in pediatric temporal lobe epilepsy, most commonly manifesting as mesial temporal sclerosis, which demonstrates hypometabolism at interictal PET and hypermetabolism during seizures. Recently, FDG PET has shown added value for patients with extratemporal epilepsy, in whom FDG PET can help identify cortical foci of interictal hypometabolism that are undetectable or difficult to detect with MR imaging. These findings can then guide additional investigations and surgery. FDG PET also enhances medical decision making in children with brain tumors, in whom FDG PET can be used to (a) improve the diagnostic yield of stereotactic biopsies by detecting metabolically active areas of tumor, (b) help guide the surgeon in achieving total tumor resection, and (c) increase detection of residual or recurrent tumor. Technologic advances in the past decade have allowed fusion of PET and MR images, combining the high resolution of MR imaging with the low-resolution functional capability of PET. As dual-modality integrated PET/MR imaging systems become available, CT coregistration for PET can be eliminated, thus reducing patient radiation exposure. Increasing familiarity with normal and abnormal appearances of FDG PET brain images correlated with MR images can enhance diagnostic yield and improve the care of children with epilepsy and brain tumors.

Primary extraosseous Ewing sarcoma of the lung: Case report and literature review.

Ewing sarcoma is the second most common primary osseous malignancy in children and young adults. However, infrequently, it can arise outside the skeletal system; rarer still, it can originate within the lung parenchyma. In this case report, we describe such a case in a 23-year-old male. We also review the literature to summarize imaging findings for this rare malignancy.

Presyrinx in a child with acquired Chiari I malformation.

Spinal cord signal abnormality resulting from alterations in cerebrospinal fluid flow at the craniocervical junction has been termed a presyrinx state. This condition has been described in the adult literature in association with a variety of conditions that cause obstruction to normal cerebrospinal fluid flow. We present a case of presyrinx in a child in the setting of acquired Chiari I malformation caused by lumboperitoneal overshunting. Awareness of the potentially reversible nature of this condition might allow for intervention before irreversible neurological damage has occurred.

Pediatric intestinal transplantation: normal radiographic appearance and complications.

We present a pictorial essay on pediatric intestinal transplantation that describes the indications for pediatric intestinal transplantation, surgical technique, and the role of imaging in the pre-transplant work-up and detection of post-transplant complications. We illustrate the normal post-transplant imaging appearance and common complications, including rejection, infection, post-transplant lymphoproliferative disease (PTLD), mechanical dysfunction and vascular complications. We conclude with an imaging algorithm for suspected post-transplant complications based on clinical scenarios.

Measuring aortic diameter with different MR techniques: comparison of three-dimensional (3D) navigated steady-state free-precession (SSFP), 3D contrast-enhanced magnetic resonance angiography (CE-MRA), 2D T2 black blood, and 2D cine SSFP.

PURPOSE: To compare nongated three-dimensional (3D) contrast-enhanced magnetic resonance angiography (CE-MRA) with 3D-navigated cardiac-gated steady-state free-precession bright blood (3D-nav SSFP) and noncontrast 2D techniques for ascending aorta dimension measurements. MATERIALS AND METHODS: Twenty-five clinical exams were reviewed to evaluate the ascending aorta at 1.5T using: breathhold cine bright blood (SSFP), cardiac-triggered T2 black blood (T2 BB), axial 3D-nav SSFP, and nongated 3D CE-MRA. Three radiologists independently measured aortic size at three specified locations for each sequence. Means, SDs, interobserver correlation, and vessel edge sharpness were statistically evaluated. RESULTS: Measurements were greatest for 3D-nav SSFP and 3D CE-MRA and smallest for T2 BB. There was no significant difference between 3D-nav SSFP and 3D CE-MRA (P = 0.43-0.86), but significance was observed comparing T2 BB to all sequences. Interobserver agreement was uniformly >0.9, with T2 BB best, followed closely by 3D-nav SSFP and 2D cine SSFP, and 3D CE-MRA being the worst. Edge sharpness was significantly poorer for 3D CE-MRA compared to the other sequences (P < 0.001). CONCLUSION: If diameter measurements are the main clinical concern, 3D-nav SSFP appears to be the best choice, as it has a sharp edge profile, is easy to acquire and postprocess, and shows very good interobserver correlation.

Diagnostic errors in polytrauma: a structured review of the recent literature.

Clinically important diagnostic errors are relatively common among polytrauma patients (2-40%). Errors are not random; they are more frequent in the spine and periarticular appendicular skeleton, especially in hemodynamically unstable patients who require resuscitation or operative intervention before completion of secondary or tertiary clinical survey. Misleading history, distracting findings, and misjudgments all contribute to risks of diagnostic errors.