Improving diagnostic efficacy of primary prostate cancer with combined 99mTc-PSMA SPECT/CT and multiparametric-MRI and quantitative parameters
Yu Zhang, Yuanying Shi, Liefu Ye, Tao Li, Yongbao Wei, Zhiyi Lin, Wenxin Chen
Abstract
Purpose This prospective study aimed to evaluate the difference between 99m Tc-PSMA single-photon emission computed tomography (SPECT)/CT and multiparametric magnetic resonance imaging (mpMRI) in the detection of primary prostate cancer (PCa). Materials and methods Fifty-six men with suspected PCa between October 2019 and November 2022 were prospectively enrolled in this study. The median age of the patients was 70 years (range, 29-87 years). Patients were divided into high-(Gleason score>7, n=31), medium- (Gleason score=7, n=6) and low-risk groups (Gleason score < 7, n=6). All patients underwent 99m Tc-PSMA SPECT/CT and mpMRI at an average interval of 3 days (range, 1-7 days). The maximum standardized uptake value (SUV max ), the minimum apparent diffusion coefficient (ADC min ), and their ratio (SUV max /ADC min ) were used as imaging parameters to distinguish benign from malignant prostatic lesions. Results Of the 56 patients, 12 were pathologically diagnosed with a benign disease, and 44 were diagnosed with PCa. 99m Tc-PSMA SPECT/CT and mpMRI showed no significant difference in the detection of primary PCa (kappa =0.401, P =0.002), with sensitivities of 97.7% (43/44) and 90.9% (40/44), specificities of 75.0% (9/12) and 75.0% (9/12), and AUC of 97.4% and 95.1%, respectively. The AUC of SUV max /ADC min was better than those of SUV max or ADC min alone. When SUV max /ADC min in the prostatic lesion was >7.0×10 3 , the lesion was more likely to be malignant. When SUV max /ADC min in the prostatic lesion is >27.0×10 3 , the PCa patient may have lymph node and bone metastases. SUV max was positively correlated with the Gleason score ( r =0.61, P=0.008), whereas ADC min was negatively correlated with the Gleason score ( r =-0.35, P =0.023). SUV max /ADC min was positively correlated with the Gleason score ( r =0.59, P =0.023). SUV max /ADC min was the main predictor of the high-risk group, with an optimal cut-off value of 15.0×10 3 . Conclusions The combination of 99m Tc-PSMA SPECT/CT and mpMRI can improve the diagnostic efficacy for PCa compared with either modality alone; SUV max /ADC min is a valuable differential diagnostic imaging parameter.