The role of whole-body MRI in pediatric oncology.

Pediatric whole-body (WB) magnetic resonance imaging (MRI) is an established technique that, with improved accessibility and advances in technology, is being used with increasing frequency for a wide variety of applications. The advantages of WB MRI (over other imaging modalities), particularly its lack of ionizing radiation (of particular concern in pediatric imaging due to children's increased sensitivity to ionizing radiation) and the ability of MRI to image the bone marrow, solid organs, and soft tissues with superior soft-tissue contrast resolution to other techniques, promise that WB MRI has great potential in conditions that are diffuse or multifocal. There is particular interest in its role in the field of pediatric oncology (eg, lymphoma, neuroblastoma, sarcoma, and Langerhans cell histiocytosis). The main disadvantages of WB MRI are its relatively long scanning times, artifacts from motion (requiring patient cooperation or general anesthesia), and limited specificity. However, advances in hardware and imaging techniques, including additional sequences (out-of-phase imaging, diffusion-weighted imaging, and contrast enhancement) are reducing the impact of some of these challenges.

Incidence of clinically silent malrotation detected on barium swallow examination in children.

INTRODUCTION: Duodenojejunal flexure (DJF) orientation is often examined routinely during contrast swallow studies, including those performed for purely oesophageal queries. We examine the radiation burden and the incidence of malrotation in patients undergoing contrast swallow, without clinical suspicion for malrotation. METHODS: Two hundred eighteen consecutive contrast swallow studies were reviewed. Patients whose history may potentially suggest malrotation were identified (n = 90), and remaining children were grouped based on whether DJF was examined (Group 1; n = 88) or not (Group 2; n = 40). Data extracted include demographics, radiographic parameters (dosage, screening time, number of images obtained) and examination findings. Outcome measures comprised: (i) prevalence of clinically incidental malrotation; and (ii) influence of additional evaluation of DJF on patient dosage (mean ± SEM). RESULTS: Malrotation was identified in 2 of 90 patients (2.2%) examined with clinical indications for possible malrotation, but none in Group 1 (13% already had normal DJF confirmed on previous examinations). Groups 1 and 2 were comparable with respect to age and gender (P = ns). Additional evaluation of DJF (Group 1) meant that 54% more images were acquired (48.5 ± 2.9 vs. 31.4 ± 3.4 images in group 2; P = 0.0002) and 24.9% increased screening time (130.8 ± 9.3 vs. 104.7 ± 13.0 seconds in group 2; P = 0.089), resulting in 32.6% increased patient dosage (1.36 ± 0.21 vs. 1.02 ± 0.16 microGym(2) /kg in group 2; P = 0.19). CONCLUSIONS: This study highlights the increased radiation exposures involved with routine screening for DJF position in those patients without clinical suspicion of malrotation, and raises questions about the validity of this practice; however, further research is needed.