Background:
Non-specific focal uptake in the skeleton is a diagnostic pitfall on 18F-PSMA-1007 PET/CT, but adjunctive
measures to aid interpretation of these lesions are currently lacking. We present two cases where dual time
point imaging provided additional information.
Case Presentation:
The first patient had a PI-RADS 3 lesion on MRI. No PSMA-avid abnormality was seen on PET, save for focal
uptake in the right pubis with no anatomic correlate. Additional imaging showed a decrease in lesion SUV, and
this was interpreted as benign. Another patient, diagnosed with prostate cancer, had multiple PSMA-avid pelvic
foci. Two suspiciously malignant bone lesions had increasing SUV trend after dual time point imaging despite
only faint sclerosis on CT. In contrast, one faint PSMA-avid lesion with no anatomic abnormality was read as
benign after a decrease in SUV. A decrease in lesion SUV may point to a benign etiology, while an increase
would heighten suspicion for malignancy. One possible molecular explanation is that a true
PSMA-overexpressing lesion would bind to the tracer for a longer period than a false positive.
Conclusion
Dual time point imaging provides additional information that may be useful in the interpretation of non-specificskeletal lesions with increased 18F-PSMA-1007 uptake.
PSMA-1007
;
Positron Emission Tomography Computed Tomography