High-resolution 18F-FDG PET/MR offers better treatment evaluation than PET/CT or MRI in CNS lymphoma

A 27-year-old woman presented with right-sided mouth droop, dizziness and impaired memory. She was sent for a brain 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography –computed tomography (PET/CT) and positron emission tomography–magnetic resonance imaging (PET/MRI). Findings from the PET/CT showed an iso- to mild hyper-attenuated lesion, with avid-FDG uptake (SUVmax 24.7), in the cerebral parenchyma involving the left basal ganglia, frontal lobe, temporal lo be, insula, thalamus, cerebral peduncle, brain stem, genu of the corpus callosum and right basal ganglia. Findings from the PET/MR additionally showed the lesion having mild hypo- to iso-intensity on T1WI and iso- to mild hyper-intensity on T2WI surrounded by edema. Histopathological results confirm ed the lesion was a diffuse large B-cell lymphoma (non-GCB type). The patient received a 6-cycle chemotherapeutic regimen including rituximab, methotrexate and temozolomide.18F-FDG PET/CT and PET/MR were repeated after treatment. The follow-up PET/CT showed the original lesion was diminished, with a severely reduced FDG uptake, indicating no remaining cancer tissue. The follow-up PET/MR confirmed the PET/CT findings for the original lesion. In addition, an onset lesion in the right rostrum of the corpus callosum was seen in the PET/MR. This lesion presented a hyper-intense signal on T2w and avid-FDG uptake (SUVmax 10.7, as shown by the yellow arrows inFig. 1). The patient subsequently received an additional two...
Source: Japanese Journal of Clinical Oncology - Category: Cancer & Oncology Source Type: research