Diffusion weighted imaging of pediatric and adolescent malignancies with regard to detection and delineation: initial experience.

RATIONALE AND
OBJECTIVE: To assess the value of diffusion weighted imaging (DWI) magnetic resonance imaging (MRI) in pediatric and adolescent tumor patients with focus on detection and delineation of malignant tumors of the central nervous system, chest, abdomen, and musculoskeletal system.
MATERIALS AND METHODS: Twenty-nine pediatric and adolescent patients (17 males, 12 females, age, 2 months-20 years, mean age: 8.9 years) with clinically suspected malignant tumors were examined with use of a 1.5-T MR scanner with open bore design without sedation or general anesthesia. DWI images were acquired with a single-shot echo planar imaging (EPI) sequence in free breathing with b-values of 0, 500, and 1000 mm/s(2). Images were assessed by two readers in consensus. Artifacts in DWI were graded as not relevant, acceptable, or nondiagnostic. DWI/apparent diffusion coefficient maps were correlated with T1-weighted post-contrast images, and the detectability and correct delineation of the tumors were graded using a three grade scale.
RESULTS: Free-breathing DWI was successfully performed in all patients. In 27 patients, no relevant artifacts were observed; acceptable artifacts were seen in two patients. In all patients, malignancies were detected both on DWI and T1-weighted gadolinium images. Detection and delineation of tumors were possible in all cases with both sequences; T1-weighted gadolinium imaging was superior to DWI in only three patients. Additionally, small diffusion restricted lymph nodes were detected in three patients.
CONCLUSION: DWI is reliable for the accurate detection and delineation of malignant pediatric and adolescent tumors.