Comparison of Diagnostic Performance Between Manual Diagnosis Following PROMISE V2 and aPROMISE Utilizing Ga/F-PSMA PET-CT

Backgrounds Automated PROMISE (aPROMISE), which is an artificial intelligence-supported software for prostate-specific membrane antigen (PSMA) PET-CT based on PROMISE V2, has demonstrated diagnostic utility with better correspondence rates compared to manual diagnosis. However, previous studies have consistently utilized F-PSMA PET-CT. Therefore, we investigated the diagnostic utility of aPROMISE using both F- and Ga-PSMA PET-CT of Japanese patients with metastatic prostate cancer (mPCa). Materials and Methods We retrospectively evaluated 21 PSMA PET-CT images (Ga-PSMA PET-CT: n = 12, F-PSMA PET-CT: n = 9) from 21 patients with mPCa. A single, well-experienced nuclear radiologist performed manual diagnosis following PROMISE V2 and subsequently performed aPROMISE-assisted diagnosis to assess miTNM and details of metastatic sites. We compared the diagnostic time and correspondence rates of miTNM diagnosis between manual and aPROMISE-assisted diagnoses. Additionally, we investigated the differences in diagnostic performance between the two radioisotopes. Results aPROMISE-assisted diagnosis was significantly associated with shorter median diagnostic time compared to manual diagnosis (427 seconds [IQR: 370–834] vs. 1,114 seconds [IQR: 922–1291], p < 0.001). The time reduction with aPROMISE-assisted diagnosis was particularly notable when using Ga-PSMA PET-CT. aPROMISE had high diagnostic accuracy with 100% sensitivity for miT, M1a, and M1b stages. Notably, for M1b stages, aPROMISE achieved 100% sensitivity and specificity, regardless of the type of radioisotope used. However, aPROMISE missed five visceral metastases (2 adrenal and 3 liver), resulting in lower sensitivity for miM1c stage (63%). In addition to detecting metastatic sites, aPROMISE successfully provided detailed metrics, including the number of metastatic lesions, total metastatic volume, and SUV mean. Conclusions aPROMISE-assisted diagnosis significantly reduces diagnostic time and achieves high accuracy compared to manual diagnosis, regardless of the type of radioisotopes used. While aPROMISE successfully detects bone metastases, its limitations in detecting visceral metastases need to be addressed. This study supports the utility of aPROMISE in Japanese patients with mPCa and underscore the need for further validation in larger cohorts.