Potential Causes of False-Negative Interpretations in 68Ga-PSMA PET/CT for the Detection of Local and Recurrent Prostate Cancer: An Underexposed Issue.

Ga-PSMA PET/CT has emerged as a highly promising diagnostic method for the evaluation of prostate cancer. Although it is increasingly recognized that its specificity is imperfect, data on false-negatives in the prostate have been underreported. We present 3 cases with false-negatives for local (recurrent) prostate cancer on Ga-PSMA PET/CT, using multiparametric MRI and histopathology as reference standard. Metal artifact of prostate gold markers placed for external beam radiation therapy, low level of PSMA uptake, and bladder spillover are potential causes of misinterpretation. Awareness of these diagnostic pitfalls may improve Ga-PSMA PET/CT interpretation.