Magnetic Resonance Imaging Provides Useful Diagnostic Information Following Equivocal Ultrasound in Children With Suspected Appendicitis [Formula: see text].

PURPOSE: In Canada, ultrasonography is the primary imaging modality for children with suspected appendicitis, yet equivocal studies are common. Magnetic resonance imaging provides promise as an adjunct imaging strategy. The primary objective of this study was to determine the proportion of children with suspected appendicitis and equivocal ultrasound where magnetic resonance imaging determined a diagnosis. METHODS: A prospective consecutive cohort of children aged 5-17 years presenting to a tertiary pediatric Emergency Department with suspected appendicitis were enrolled. Participants underwent diagnostic and management strategies according to our local suspected appendicitis pathway, followed by magnetic resonance (Siemens Avanto 1.5 Tesla) imaging. Sub-specialty pediatric radiologists reported all images. RESULTS: Magnetic resonance imaging was performed in 101 children with suspected appendicitis. The mean age was 11.9 (SD 3.4) years and median Pediatric Appendicitis Score was 6 [IQR 4,8]. Ultrasonography was completed in 98/101 (97.0%). Of 53/98 (54.1%) with equivocal ultrasound, magnetic resonance imaging provided further diagnostic information in 41 (77.4%; 10 positive, 31 negative; 12 remained equivocal). Secondary findings of appendicitis on magnetic resonance imaging in children with equivocal ultrasound included abdominal free fluid (24, 45.3%), peri-appendiceal fluid (12, 22.6%), intraluminal appendiceal fluid (9, 17.0%), fat stranding (8, 15.1%), appendicolith (2, 3.8%), and peri-appendiceal abscess (1, 1.9%). The observed agreement between magnetic resonance imaging results and final diagnosis was 94.9% (kappa = 0.89).

Magnetic resonance imaging of a restrictive atrial septal defect in a univentricular connection.

Magnetic resonance imaging (MRI) provides accurate and valuable information regarding cardiac shunts including their location, size, and flow. We describe the MRI findings of a restrictive atrial septal defect within a complex case of congenital heart disease: univentricular atrioventricular connection of left ventricular type with right-sided discordant atrioventricular connection (single), absent left atrioventricular connection, and ventriculoarterial discordance. Few similar cases are reported in the literature. Magnetic resonance imaging may add valuable information regarding restrictive atrial shunts in univentricular hearts.

Widespread osteonecrosis in children with leukemia revealed by whole-body MRI.

BACKGROUND: Confirmation of early long-bone epiphyseal osteonecrosis in pediatric patients with leukemia allows for medical and surgical intervention before articular surface collapse. MRI detects early osteonecrosis, but multiple focused MR images are required to capture all lesions. QUESTIONS/PURPOSES: We determined whether whole-body MRI (WB-MRI) could (1) assist in diagnosing long-bone epiphyseal and other osteonecroses, (2) characterize articular surface involvement, and (3) detect preferential sites for osteonecrosis. PATIENTS AND METHODS: We retrospectively reviewed prospectively collected data on all 11 pediatric patients newly diagnosed with leukemia who had musculoskeletal pain develop that persisted 4 weeks or more during leukemia treatment. All were screened for osteonecrosis by WB-MRI, which consisted of a one-time scan of the entire body. Osteonecrosis was defined as circumscribed lesions with a distinct rim of low signal intensity in the normally high-intensity marrow on T1-weighted images and high signal intensity in the normally low-intensity marrow on short-tau inversion recovery images. RESULTS: WB-MRI confirmed osteonecrosis in nine of 11 patients. All patients had multisite lesions; eight had long-bone epiphyseal lesions, which comprised 66 of 129 (51%) of all lesions. Osteonecrosis involving greater than 50% of the epiphyseal surface was present in 57% of distal femoral and proximal tibial lesions. All humeral and femoral head lesions involved more than 1/3 of the medial surface volume but were asymptomatic. No articular collapse was present. All osteonecrotic lesions were more common in the lower extremities. CONCLUSIONS: WB-MRI confirmed early epiphyseal osteonecrosis, with quantification of articular surface involvement. Lower limbs were preferentially affected, but asymptomatic humeral head osteonecrosis was present in five of nine patients. LEVEL OF EVIDENCE: Level IV, diagnostic study. See Instructions for Authors for a complete description of levels of evidence.