Correlation of Standardized Uptake Value and Apparent Diffusion Coefficient in Integrated Whole-Body PET/MRI of Primary and Recurrent Cervical Cancer

BACKGROUND: To evaluate a potential correlation of the maximum standard uptake value (SUV(max)) and the minimum apparent diffusion coefficient (ADC(min)) in primary and recurrent cervical cancer based on integrated PET/MRI examinations. METHODS: 19 consecutive patients (mean age 51.6 years; range 30–72 years) with histopathologically confirmed primary cervical cancer (n = 9) or suspected tumor recurrence (n = 10) were prospectively enrolled for an integrated PET/MRI examination. Two radiologists performed a consensus reading in random order, using a dedicated post-processing software. Polygonal regions of interest (ROI) covering the entire tumor lesions were drawn into PET/MR images to assess SUV(max) and into ADC parameter maps to determine ADC(min) values. Pearson’s correlation coefficients were calculated to assess a potential correlation between the mean values of ADC(min) and SUV(max). RESULTS: In 15 out of 19 patients cervical cancer lesions (n = 12) or lymph node metastases (n = 42) were detected. Mean SUV(max) (12.5±6.5) and ADC(min) (644.5±179.7×10(−5) mm(2)/s) values for all assessed tumor lesions showed a significant but weak inverse correlation (R = −0.342, p<0.05). When subdivided in primary and recurrent tumors, primary tumors and associated primary lymph node metastases revealed a significant and strong inverse correlation between SUV(max) and ADC(min) (R = −0.692, p<0.001), whereas recurrent cancer lesions did not show a significant correlation. CONCLUSIONS: These initial results of this emerging hybrid imaging technique demonstrate the high diagnostic potential of simultaneous PET/MR imaging for the assessment of functional biomarkers, revealing a significant and strong correlation of tumor metabolism and higher cellularity in cervical cancer lesions.