Abdominal neuroblastoma: magnetic resonance imaging and tissue characterization

Magnetic resonance imaging was performed in eight children with abdominal neuroblastomas. Five patients had serial examinations after diagnosis, and 15 computed tomography (CT) scans were available for comparison. MR imaging was as precise as CT in detecting the presence or absence of liver involvement and more efficient in determining the relationship of tumor to vascular structures. However, it did not differentiate tumor from normal kidney as accurately as CT. Inversion recovery (IR) images yielded the greatest soft-tissue contrast resolution between liver and tumor. T1 values of tumor were much higher than those of normal liver but overlapped those of normal kidneys. T2 values of tumor were significantly higher than those of the liver and were slightly, but not significantly, lower than those of the kidneys. Either T1- or T2- weighted pulse sequences should, therefore, provide adequate liver-tumor differentiation, but more heavily T2- weighted images appear necessary to distinguish between tumor and kidney. T1 values of tumors usually decreased with rapid tumor regression, while T2 values changed independently. The ability to quantitate tissue parameters helps in selecting appropriate imaging sequences and may be of use in following the progress of tumors.