Non-Hodgkin lymphoma: predicting prognostic grade with MR imaging.

Fifty patients with non-Hodgkin lymphoma (NHL) were examined with magnetic resonance (MR) imaging in order to analyze whether it is possible to distinguish in vivo between the two major prognostic groups, low-grade NHL and high-grade NHL. Most high-grade NHL nodes (15 of 24 [63%]) had an inhomogeneous appearance at MR imaging, in contrast to low-grade NHL nodes, which were homogeneous in almost all patients (18 of 20 [90%]) (P less than .001). A homogeneous image was also found in six patients who had previously received a diagnosis of low-grade NHL; at the time of examination their lesions had transformed into high-grade NHL. Necrosis, detectable in the histopathologic sections, was usually (five of six cases) associated with an inhomogeneous image. However, the images were also inhomogeneous [corrected] in 12 of 44 cases (27%) in which there were no signs of necrosis in the histopathologic sections. Patients with high-grade NHL and a homogeneous signal intensity pattern tended to have a better survival rate than those with an inhomogeneous pattern.