Accurate Estimation of the Duration of Testicular Ischemia Using Creatine Chemical Exchange Saturation Transfer (CrCEST) Imaging.

BACKGROUND In the management of testicular torsion, estimating the duration of testicular ischemia is essential for deciding on an appropriate surgical treatment, but there are currently limited evaluation methods. PURPOSE To perform testicular creatine chemical exchange saturation transfer (CrCEST) imaging and to evaluate its ability to accurately estimate the duration of testicular ischemia. STUDY TYPE Prospective. ANIMAL MODEL C57BL/6 control mice (n = 6) and testicular ischemia models induced by clamping the spermatic cord (n = 14). Eight of testicular ischemia models were serially imaged at two or three timepoints and a total of 26 images of ischemic testis were obtained. The ischemic duration ranged from 6-42 hours. FIELD STRENGTH/SEQUENCE 11.7T vertical-bore MRI/segment fast low-angle shot acquisition for CEST. ASSESSMENT CrCEST imaging was performed and the magnetization transfer ratio for the CrCEST effect (MTRCr** ) was calculated in control mice and testicular ischemia models. Correlation analysis between the duration of testicular ischemia and MTRCr** decline was performed. STATISTICAL TESTS Paired t-test, and Pearson's correlation analysis. RESULTS In control mice, the CrCEST effect in testes was significantly more than five times higher than that in skeletal muscle. MTRCr** did not differ significantly between the right and left testes (8.6 ± 0.8 vs. 8.3 ± 0.6, P = 0.96). In testicular ischemia models, MTRCr** of ischemic testes was significantly lower than that of controls (4 ± 2 vs. 8.9 ± 0.6, P < 0.001). Correlation analysis revealed a strong linear correlation between MTRCr** decline and the duration of ischemia (r = 0.96, P < 0.001). DATA CONCLUSION A decreased CrCEST effect in ischemic testes correlated well with ischemic duration. Testicular CrCEST imaging was useful for accurately estimating the duration of testicular ischemia. LEVEL OF EVIDENCE 2 TECHNICAL EFFICACY STAGE: 2.