Abstract:
Objective To evaluate the diagnostic value of 99Tcm-methylene disphosphonate (MDP) SPECT/CT fusion imaging in pelvic metastases in tumor patients.
Methods The clinical data of 148 patients diagnosed with malignant tumor and suspected bone metastasis were retrospectively analyzed in Sichuan Cancer Hospital from August 2018 to December 2018. The patients, composed of 77 males and 71 females aged 29–86 (48.8±14.5) years, were divided into primary pelvic tumor group (63 cases) and non-primary pelvic tumor group (85 cases). All the patients underwent SPECT/CT fusion imaging of the abnormal concentration of the pelvis after first SPECT whole-body plane bone imaging. After 6 months to 1 year of follow-up with histomathological examination and imaging examination(SPECT, CT, SPECT/CT, and MRI), the coincidence rates, accuracy, and positive predictive values of SPECT whole-body plane bone imaging and SPECT/CT fusion imaging in the diagnosis of bone metastasis were compared. Qualitative data were compared by Pearson χ2 test. One-way analysis of variance was used in comparing the positive predictive values of multiple imaging tests.
Results A total of 309 lesions with increased metabolism were detected through SPECT whole-body plane bone imaging, of which 239 were consistent with the follow-up results. The diagnostic coincidence rate was 77.3% (239/309), the accuracy rate of bone metastasis was 92.9% (208/224), and the accuracy rate of benign lesions was 77.3% (34/44). A total of 367 lesions with increased metabolism were detected by SPECT/CT fusion imaging, of which 349 were consistent with the results obtained through follow-up. The diagnostic coincidence rate was 95.1% (349/367), the accuracy rate of bone metastasis was 98.4% (299/304), and the accuracy rate of benign lesions was 87.7% (50/57). Statistically significant differences in diagnostic coincidence rate, diagnostic accuracy of bone metastasis, and diagnostic accuracy of benign lesions were found (χ2=0.595, 28.795, 4.546, all P<0.01). The number of lesions detected by SPECT/CT fusion imaging in the pelvic lesions was higher than that detected through SPECT whole-body plane bone imaging, and the number of lesions detected in the primary pelvic tumor group was higher than that in the non-primary pelvic tumor group, and the difference was statistically significant (χ2=17.385, P=0.036). The positive predictive value of SPECT/CT was the highest (84%, 52/62), followed by those of SPECT (79%, 48/61), MRI (76%, 47/62), and CT (65%, 39/60), and the differences were statistically significant (F=5.492, P=0.003).
Conclusion Compared with SPECT plane bone imaging, 99Tcm-MDP SPECT/CT can improve the accuracy of differential diagnosis of pelvic metastases in tumor patients, and the application of 99Tcm-MDP SPECT/CT fusion examination can improve the detection rate of bone metastases in primary pelvic tumors.