PET-MR Examination in Diagnosing Bone Metastases in Prostate Cancer

Background: Positron Emission Tomography-magnetic resonance (PET-MR) has the advantage of high contrast and has a high potential for diagnosing bone metastases in prostate cancer (PC). This study assesses the effectiveness of PET-MR imaging for detecting bone metastasis in PC. Methods: A total of 212 prostate cancer patients admitted to our hospital from June 2021 to June 2024 were selected, all of whom were diagnosed with prostate cancer through pathological puncture. According to the most valuable comparative method (BVC), patients were divided into a bone metastasis group (n=40) and a non-bone metastasis group (n=172). General information such as age was collected and compared between the two groups of patients. PET-MR examination was performed on all patients, and the number of lesions was recorded (a total of 95 bone metastases were detected). Among them, BVC confirmed 58 metastatic lesions (due to the presence of multiple site metastases in some patients). The Gleason score, SUV max , and ADC min levels were compared between groups. ROC curve analysis determined the AUC, sensitivity, and specificity. Multivariate Logistic regression identified influencing factors. Results: Among patients with bone metastases, 38 patients with positive PET-MR (95.00%) and 169 patients with non-bone metastases (79.72%) were PET-MR negative. The sensitivity of PET-MR in diagnosing prostate cancer bone metastasis was 95.00% (95% CI: 83.5% - 99.4%), the specificity was 79.72% (95% CI: 73.1% - 85.3%), the positive predictive value was 92.68% (95% CI: 80.1% - 98.4%), and the negative predictive value was 98.83% (95% CI: 95.8% - 99.9%). The proportion of PET-MR diagnosed prostate cancer bone metastases with pelvic, spinal, extremity, rib, and scapular lesions were 31.03%, 44.83%, 8.62%, 3.45%, and 87.93%, respectively. Compared with the non-metastatic group, the proportion of patients with Gleason score > 9, the proportion of tPSA > 100 ng/mL, ALP level and SUV max and SUV max /ADC min levels were significantly higher in the metastatic group. ADC min levels were significantly lower, and the differences were statistically significant (P < 0.05). Factors such as PET-MR positivity, Gleason score > 9, tPSA > 100 ng/mL, ALP level, SUV max , ADC min and SUV max /ADC min were significant risk factors for bone metastasis (P< 0.05). The AUC of SUV max , ADC min and SUV max /ADC min in the diagnosis of bone metastasis of prostate cancer were 0.756, 0.777 and 0.864, respectively. SUV max , ADC min and SUV max /ADC min were abnormally expressed in bone metastases of PC by PET-MR examination. Conclusion: SUV max , ADC min , and SUV max /ADC min are significantly abnormally expressed in patients with prostate cancer bone metastases during PET-MR examination. The sensitivity and specificity of PET-MR in diagnosing prostate cancer bone metastasis are 95.00% and 79.72%, respectively. Among them, the SUV max /ADC min ratio has the best diagnostic efficacy (AUC = 0.864, sensitivity 76.74%, specificity 82.50%). PET-MR has certain value in the diagnosis of prostate cancer bone metastasis and can be used as a reference indicator for clinical auxiliary evaluation.