Magnetic Resonance Neuroimaging In Sacral Nerve After HIFU Ablation Of Uterine Fibroids

Objective:To compare the sacral plexus in healthy volunteers and patients with uterine fibroids by DTI and MATRIX imaging.Methods:DTI and MATRIX scanning of S1-S3 nerve were performed in 30 healthy female volunteers and 42 patients with uterine fibroids using 3.0T magnetic resonance.The FA and ADC values of the sacral nerve were measured in healthy volunteers and patients with uterine fibroids using the sacral nerve as the region of interest at the outlet of the sacral foramen.The sacral nerve was analyzed by multiple planar reconstruction at the same time.The differences in DTI parameters of sacral nerve between volunteer group and uterine fibroid group were analyzed using t test.Results:(1)The FA value ratios of the left and right sides of the S1-S3 nerve in the volunteer group were respectively(0.425 ±0.035∝0.420 ±0.039,0.421±0.043∝0.413±0.026,0.408±0.025∝0.404±0.022),P>0.05,and the ADC values of the left and right sides were respectively(1.382±0.100×10-3mm2/s∝1.392±0.118±10-3mm2/s,1.342±0.108×10-3mm2/s∝1.392±0.118×10-3mm2/s,1.369±0.136×10-3mm2/s∝1.338±0.122×10-3mm 2/s),P>0.05.The differences for each comparison was statistically insignificant.(2)The FA values of the left and right S1-S3 nerves in the fibroid group were respectively(0.433±0.027∝0.428±0.030,0.408±0.024∝0.407±0.032,0.395±0.031∝0.393±0.030),P>0.05,and the ADC values of the left and right sides were respectively(1.352±0.111×10-3mm2/s∝1.395±0.112×10-3mm2/s,1.356±0.146×10-3mm2/s∝1.389±0.168×10-3mm2/s,1.351±0.157×10-3mm2/s∝1.317±0.168×10-3mm2/s),P>0.05.The differences for each comparison was statistically insignificant.(3)The ADC and FA values of the left and right S1-S3 nerve roots in the volunteer group were compared with the DTI parameters of the same segment of the nerve in the fibroid group,and there was no significant difference(P>0.05).(4)Multiple planar reconstruction can continuously and completely show S1-S3 nerve fibers.In the volunteer fibroid group,the nerve course is natural,without interruption or distortion,the edge is sharp,and there is no obvious abnormality in the signals of the two.Conclusion:DTI and MATRIX can quantitatively describe the diffusion characteristics of sacral plexus and visually display sacral plexus.Uterine fibroids do not cause changes in the microstructure of the sacral nerve.Objective:To show the changes of sacral nerve after HIFU ablation of uterine fibroids by DTI and MATRIX imaging,and to analyze the factors causing the changes.Methods:Forty-two patients who underwent HIFU ablation of uterine fibroids in our hospital were recruited and underwent S1-S3 nerve DTI and MATRIX scanning within one week before surgery and one day after surgery.The signal changes of the sacral nerve before and after HIFU ablation of fibroids were compared and analyzed using the sacral nerve at the foraminal outlet as the region of interest.At the same time,multiple planar reconstruction of the sacral nerve was performed before and after HIFU ablation to observe the changes in nerve signal and morphology.The relationship between sacral nerve signal changes and patients’ general data and treatment parameters was also analyzed.Results:(1)The FA values of the left side of S1-S3 nerve before and after operation were respectively(0.434±0.028∝0.384±0.031,0.408±0.024∝0.357±0.028,0.395±0.031∝0.328±0.037,P<0.05).The FA values of the right S1-S3 nerve before and after operation were respectively(0.428±0.030∝0.375±0.045,0.407±0.032∝0.349±0.032,0.392±0.030∝0.330±0.037,P<0.05).The ADC values of the left side of S1-S3 nerve before and after operation were respectively(1.352±0.111×10-3mm2/s∝1.508±0.187×10-3mm2/s,1.357±0.146×10-3mm2/s∝1.567±0.221×10-3mm2/s,1.351±0.157×10-3mm2/s∝1.597±0.298×10-3mm2/s,P<0.05).The differences for each comparison was statistically significant.The ADC values on the right side of the S1-S3 nerve before and after surgery were respectively(1.395±0.112×10-3mm2/s∝1.591±0.240×10-3mm2/s,1.390±0.168×10-3mm2/s∝1.615±0.217×10-3mm2/s,1.317±0.168×10-3mm2/s∝1.527±0.276×10-3mm2/s,P<0.05).The differences for each comparison was statistically significant.(2)Postoperative FA and ADC values of the left and right sides of the S1-S3 nerve were compared,respectively,and there were no significant differences(P>0.05).(3)The morphology of all sacral nerves did not change significantly after surgery,but some nerves showed varying degrees of signal enhancement,including 22 cases with nerve signal enhancement and 20 cases without nerve signal enhancement.(4)The distance between the dorsal surface of the fibroid and the sacrum,the total ablation time and the total energy and sacral nerve signal enhancement were statistically significant in univariate analysis(P<0.05).In logistic regression analysis the distance between the dorsal surface of the fibroid and the sacrum was negatively correlated with nerve injury,and the total energy of ablation was positively correlated with nerve injury.Conclusion:DTI and MATRIX techniques can assess sacral plexus injury during ultrasound-guided HIFU ablation of uterine fibroids.The distance between the dorsal surface of the fibroid and the sacrum and the total energy of ablation are two independent risk factors for increased sacral nerve signal.