Optimal MRI sequences for (68)Ga-PSMA-11 PET/MRI in evaluation of biochemically recurrent prostate cancer

PET/MRI can be used for the detection of disease in biochemical recurrence (BCR) patients imaged with (68)Ga-PSMA-11 PET. This study was designed to determine the optimal MRI sequences to localize positive findings on (68)Ga-PSMA-11 PET of patients with BCR after definitive therapy. Fifty-five consecutive prostate cancer patients with BCR imaged with (68)Ga-PSMA-11 3.0T PET/MRI were retrospectively analyzed. Mean PSA was 7.9 ± 12.9 ng/ml, and mean PSA doubling time was 7.1 ± 6.6 months. Detection rates of anatomic correlates for prostate-specific membrane antigen (PSMA)-positive foci were evaluated on small field of view (FOV) T2, T1 post-contrast, and diffusion-weighted images. For prostate bed recurrences, the detection rate of dynamic contrast-enhanced (DCE) imaging for PSMA-positive foci was evaluated. Finally, the detection sensitivity for PSMA-avid foci on 3- and 8-min PET acquisitions was compared.

PSMA-positive foci were detected in 89.1% (49/55) of patients evaluated. Small FOV T2 performed best for lymph nodes and detected correlates for all PSMA-avid lymph nodes. DCE imaging performed the best for suspected prostate bed recurrence, detecting correlates for 87.5% (14/16) of PSMA-positive prostate bed foci. The 8-min PET acquisition performed better than the 3-min acquisition for lymph nodes smaller than 1 cm, detecting 100% (57/57) of lymph nodes less than 1 cm, compared to 78.9% (45/57) for the 3-min acquisition.

PSMA PET/MRI performed well for the detection of sites of suspected recurrent disease in patients with BCR. Of the MRI sequences obtained for localization, small FOV T2 images detected the greatest proportion of PSMA-positive abdominopelvic lymph nodes and DCE imaging detected the greatest proportion of PSMA-positive prostate bed foci. The 8-min PET acquisition was superior to the 3 min acquisition for detection of small lymph nodes.

EJNMMI research. 2017 Sep 19*** epublish ***

Spencer T Lake, Kirsten L Greene, Antonio C Westphalen, Spencer C Behr, Ronald Zagoria, Eric J Small, Peter R Carroll, Thomas A Hope

Department of Radiology and Biomedical Imaging, University of California, 505 Parnassus Avenue - 0628, San Francisco, CA, 94143-0628, USA., Department of Urology, University of California, 1825 4th Street, 4th floor, UCSF Ron Conway Family Gateway Medical Building, San Francisco, CA, 94158, USA., UCSF Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA., Department of Radiology and Biomedical Imaging, University of California, 505 Parnassus Avenue - 0628, San Francisco, CA, 94143-0628, USA. .

E-Newsletters

Newsletter subscription

Free Daily and Weekly newsletters offered by content of interest

The fields of GU Oncology and Urology are rapidly advancing. Sign up today for articles, videos, conference highlights and abstracts from peer-review publications by disease and condition delivered to your inbox and read on the go.

Subscribe