Comparison of three interpretation criteria of 68Ga-PSMA11 PET based on inter- and intra-reader agreement.

ÌÇÐÄ´«Ã½

Abstract

Positron emission tomography (PET) using radiolabeled prostate specific membrane antigen (PSMA) is now more and more widely adopted as a valuable tool to evaluate patients with prostate cancer (PC). Recently, three different criteria for interpretation of PSMA PET were published: European Association of Nuclear Medicine (EANM) criteria, prostate cancer molecular imaging standardized evaluation (PROMISE) criteria, and PSMA-reporting and data system (PSMA-RADS). We compared these three criteria in terms of inter-reader, intra-reader, and inter-criteria agreement. Methods: Data from 104 patients prospectively enrolled in ÌÇÐÄ´«Ã½ protocols at our institution were retrospectively reviewed. The cohort consisted of two groups: 47 patients (mean age: 64.2 years old) who underwent Glu-NH-CO-NH-Lys-(Ahx)-[68Ga(HBED-CC)] (68Ga-PSMA11) PET/magnetic resonance imaging (MRI) for initial staging of biopsy-proven intermediate- or high-risk PC, and 57 patients (mean age: 70.5 years old) who underwent 68Ga-PSMA11 PET/computed tomography (CT) due to biochemically recurrent (BCR) PC. Three nuclear medicine physicians independently evaluated all 68Ga-PSMA11 PET/MRI and PET/CT studies according to the three interpretation criteria. Two of them reevaluated all studies 6 months later in the same manner and blinded to the initial reading. Gwet's AC was calculated to evaluate inter- and intra-reader, and inter-criteria agreement based on the following sites: local lesion (primary tumor or prostate bed after radical prostatectomy), lymph node metastases, and other metastases. Results: In the PET/MRI group, inter-reader, intra-reader, and inter-criteria agreements were substantial to almost perfect in any sites according to all of the three criteria. In the PET/CT group, inter-reader agreement was substantial to almost perfect except judgement of distant metastases based on PSMA-RADS (Gwet's AC = 0.57, moderate agreement), in which the most frequent cause of disagreement was lung nodules. Intra-reader agreements were substantial to almost perfect in any sites according to all of the three criteria. Inter-criteria agreements of each site were also substantial to almost perfect. Conclusion: Although the three published criteria have good inter-reader and intra-reader reproducibility in evaluating 68Ga-PSMA11 PET, there are factors bringing inter-reader disagreement. This indicates that further work is needed to address the issue.

View details for

View details for