No correlation between glucose metabolism and apparent diffusion coefficient in diffuse large B-cell lymphoma: a PET/CT and DW-MRI study.

PURPOSE: Both positron emission tomography/computed tomography (PET/CT) and diffusion-weighted magnetic resonance imaging (DW-MRI) are oncologic feasible techniques for evaluating the malignancy of tumors. Standardized uptake value (SUV) is a marker of tumor glucose metabolism detected by PET/CT. Apparent diffusion coefficient (ADC) measured by DWI can provide information about tissue cellularity. The aim of the study was to evaluate the correlation between SUV and ADC in untreated diffuse large B-cell lymphoma (DLBCL).

MATERIALS AND METHODS: Fifteen pre-therapy patients with histologically proven DLBCL underwent PET/CT and DWI examinations within two days. Tumor glucose metabolism was evaluated by the maximum and mean SUV (SUV(max) and SUV(mean)) on the PET/CT images. The mean ADC value was measured directly on the parametric ADC maps.

RESULTS: In total, 28 lymphoma lesions with best match PET/CT and DWI were identified and evaluated. The mean SUV(max) and SUV(mean) were 16.8 and 11.1, respectively; the mean ADC was 0.74 × 10(-3)mm(2)/s. There was no correlation between the mean ADC and the SUV(max) or SUV(mean).

CONCLUSION: SUV determined from PET/CT and ADC value measured from DWI are different indices for the diagnosis of tumor malignancy, they may provide complimentary functional information of tumor tissue.