RT Journal Article SR Electronic T1 Diagnostic Performance of 68Ga-PSMA-11 PET/CT Versus Multiparametric MRI for Detection of Intraprostatic Radiorecurrent Prostate Cancer JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 379 OP 385 DO 10.2967/jnumed.123.266527 VO 65 IS 3 A1 Light, Alexander A1 Lazic, Stefan A1 Houghton, Kate A1 Bayne, Max A1 Connor, Martin J. A1 Tam, Henry A1 Ahmed, Hashim U. A1 Shah, Taimur T. A1 Barwick, Tara D. YR 2024 UL http://jnm.snmjournals.org/content/65/3/379.abstract AB For men with prostate cancer who develop biochemical failure after radiotherapy, European guidelines recommend reimaging with 68Ga-PSMA-11 PET/CT and multiparametric MRI (mpMRI). However, the accuracy of 68Ga-PSMA-11 PET/CT for detecting intraprostatic recurrences is unclear, both with and without mpMRI. Methods: A single-center retrospective study of a series of patients investigated for radiorecurrence between 2016 and 2022 is described. All patients underwent 68Ga-PSMA-11 PET/CT, mpMRI, and prostate biopsy. PET/CT images were interpreted independently by 2 expert readers masked to other imaging and clinical data. The primary outcome was the diagnostic accuracy of PET/CT versus mpMRI and of PET/CT with mpMRI together versus mpMRI alone. The secondary outcome was the proportion of cancers missed by mpMRI but detected by PET/CT. Diagnostic accuracy analysis was performed at the prostate hemigland level using cluster bootstrapping. Results: Thirty-five men (70 hemiglands) were included. Cancer was confirmed by biopsy in 43 of 70 hemiglands (61%). PET/CT sensitivity and negative predictive values (NPVs) were 0.89 (95% CI, 0.78–0.98) and 0.79 (95% CI, 0.62–0.95), respectively, which were not significantly different from results by MRI (sensitivity of 0.72; 95% CI, 0.61–0.83; P = 0.1) (NPV of 0.59; 95% CI, 0.41–0.75; P = 0.07). Specificity and positive predictive values were not significantly different. When PET/CT and MRI were used together, the sensitivity was 0.98 (95% CI, 0.92–1.00) and NPV was 0.93 (95% CI, 0.75–1.00), both significantly higher than MRI alone (P = 0.003 and P < 0.001, respectively). Specificity and positive predictive values remained not significantly different. MRI missed 12 of 43 cancers (28%; 95% CI, 17%–43%), of which 11 of 12 (92%; 95% CI, 62%–100%) were detected by PET/CT. Conclusion: For detecting intraprostatic radiorecurrence, 68Ga-PSMA-11 PET/CT has high sensitivity that is not significantly different from mpMRI. When 68Ga-PSMA-11 PET/CT and mpMRI were used together, the results conferred a significantly greater sensitivity and NPV than with mpMRI alone. 68Ga-PSMA-11 PET/CT may therefore be a useful tool in the diagnosis of localized radiorecurrence.