To evaluate the combined application of the maximum standardized uptake value (SUV_max) of ⁶⁸Ga-N, N′-bis(2-hydroxy-5-(carboxyethyl)benzyl) ethylenediamine-N, N′-diacetic acid(HBED-CC)-(Ahx)Lys-CO-Glu(PSMA-11)PET/CT imaging and the apparent diffusion coefficient (ADC) value of MRI in the differential diagnosis of prostate cancer (PCa).

Seventy untreated patients (age: (68.3±12.1) years) with suspected PCa between December 2016 and April 2018 were prospectively studied. All patients underwent PET/CT and MRI examinations. The SUV_max and average ADC value were measured as diagnostic parameters, and the SUV_max/ADC ratio was calculated. The sensitivity and specificity of the 3 parameters were calculated by receiver operating characteristic (ROC) curve analysis.

Of the 70 patients, 31 were pathologically diagnosed as benign diseases and 39 were as PCa. The diagnostic sensitivity and specificity of average ADC value for PCa were 81% and 72%, respectively, with a threshold value of 1.08×10^-3 mm²/s (b=1 000 s/mm²). The diagnostic sensitivity and specificity of SUV_max were 82% and 71% for PCa with a critical value of 7.69, and those were 72% and 93% with SUV_max/ADC ratio of 11.87.

The combination of ⁶⁸Ga-PSMA-11 PET/CT and MRI can improve the diagnostic specificity for PCa, and the SUV_max/ADC ratio is a valuable differential diagnostic index.

Prostatic neoplasms; Prostate-specific membrane antigen; Isotope labeling; Gallium radioisotopes; Positron-emission tomography; Tomography, X-ray computed; Magnetic resonance imaging