AUTHOR=Qin Chunxia , Gai Yongkang , Liu Qingyao , Ruan Weiwei , Liu Fang , Hu Fan , Zhang Xiaoping , Lan Xiaoli 

TITLE=Optimized Application of 68Ga-Prostate-Specific Membrane Antigen-617 Whole-Body PET/CT and Pelvic PET/MR in Prostate Cancer Initial Diagnosis and Staging

JOURNAL=Frontiers in Medicine

VOLUME=8

YEAR=2021

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2021.657619

DOI=10.3389/fmed.2021.657619

ISSN=2296-858X

ABSTRACT=<p><bold>Purpose:</bold> To analyze <sup>68</sup>Ga-PSMA-617 PET/CT or PET/MR and delayed PET/MR images in patients diagnosed with or suspicion of prostate cancer, and to explore the optimal use of PET/CT and PET/MR for initial diagnosis and staging in prostate cancer.</p><p><bold>Methods:</bold> Images from conventional scan by <sup>68</sup>Ga-PSMA whole-body PET/CT or PET/MR followed by delayed pelvic PET/MR were retrospectively analyzed. Prostatic <sup>68</sup>Ga-PSMA uptake was measured as SUVmax1 (conventional scan 1 h post injection) and SUVmax2 (delayed scan 3 h post injection). Age, PSA levels, and SUVmax were compared between benign and malignant cases. The correlation of SUVmax1 and SUVmax2 was analyzed. Diagnostic performance was evaluated by ROC analysis.</p><p><bold>Results:</bold> Fifty-six patients with 41 prostate cancers and 15 benign prostate lesions were enrolled. Fifty-three patients had paired conventional and delayed scans. Age, tPSA, fPSA levels, and SUVmax were significantly different between benign and malignant cases. A good correlation was found between SUVmax1 and SUVmax2. There was significant difference between SUVmax1 and SUVmax2 in the malignant group (<italic>p</italic> = 0.001). SUVmax1 had superior diagnostic performance than SUVmax2, SUVmax difference and PSA levels, with a sensitivity of 85.4%, a specificity of 100% and an AUC of 0.956. A combination of SUVmax1 with nodal and/or distant metastases and MR PI-RADS V2 score had a sensitivity and specificity of 100%. Delayed pelvic PET/MR imaging in 33 patients were found to be redundant because these patients had nodal and/or distant metastases which can be easily detected by PET/CT. PET/MR provided incremental value in 8 patients at early-stage prostate cancer based on precise anatomical localization and changes in lesion signal provided by MR.</p><p><bold>Conclusion:</bold> Combined <sup>68</sup>Ga-PSMA whole-body PET/CT and pelvic PET/MR can accurately differentiate benign prostate diseases from prostate cancer and accurately stage prostate cancer. Whole-body PET/CT is sufficient for advanced prostate cancer. Pelvic PET/MR contributes to diagnosis and accurate staging in early prostate cancer. Imaging at about 1 h after injection is sufficient in most patients.</p><p><ext-link ext-link-type="uri" xlink:href="http://https://ClinicalTrials.gov" xmlns:xlink="http://www.w3.org/1999/xlink"><bold>ClinicalTrials.gov</bold></ext-link><bold>:</bold> NCT03756077. Registered 27 November 2018—Retrospectively registered, <ext-link ext-link-type="uri" xlink:href="https://clinicaltrials.gov/show/NCT03756077" xmlns:xlink="http://www.w3.org/1999/xlink">https://clinicaltrials.gov/show/NCT03756077</ext-link>.</p>