The influence of digital PET/CT on diagnostic certainty and interrater reliability in ⁶⁸Ga-PSMA-11 PET/CT for recurrent prostate cancer

Ziel/Aim To evaluate the influence of digital PET/CT (dPET/CT) on diagnostic certainty, patient-based sensitivity and interrater reliability.

Methodik/Methods Two matched cohorts of patients were included who underwent ⁶⁸Ga-PSMA-11 PET/CT on a dPET/CT (n = 65) or an analogue scanner (aPET/CT) (n = 65) for recurrent prostate cancer (PC). Cohorts were matched for clinical parameters and prior treatment. Four physicians read each scan independently. The number of equivocal and pathological lesions as well as the frequency of discrepant findings and the interrater reliability for the two scanners were compared.

Ergebnisse/Results dPET/CT detected more lesions compared to aPET/CT (p < 0.001). A significantly higher number of pathological scans was observed for dPET/CT (83 % vs. 57 %, p < 0.0001). The true positive rate at clinical follow up was 100 % for dPET/CT compared to 84 % for aPET/CT (p < 0.0001) The higher number of lesions detected resulted in no significantly higher proportion of non-pathological lesions as a total of all lesions detected for dPET/CT compared to aPET/CT (61.8 % vs 57.0 %, p = 0.99). Neither the rate of diagnostically uncertain lesions (11.5 % dPET/CT vs 13.7 % aPET/CT, p = 0.95) nor discrepant scans (where one or more readers differed in opinion as to whether the scan is pathological) was observed (18 % dPET/CT vs. 17 % aPET/CT, p = 0.76). No correlation was found between numbers of pathological and equivocal lesions. Interrater reliability for pathological lesions was excellent for both scanner types (Cronbach’s α=0.923 dPET/CT; α=0.948 aPET/CT) and agreement was substantial for dPET/CT (Krippendorf’s α=0.701) and almost perfect in aPET/CT (α=0.802).

Schlussfolgerungen/Conclusions Our results confirm the higher detection rate for pathological lesions for dPET/CT compared with aPET/CT in multiple readers. This improved sensitivity was coupled with an improved true positive rate and was not associated with increased diagnostic uncertainty, false detection rate or reduced interrater reliability.

 

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Artikel online veröffentlicht:
08. April 2021