Application Of 3.0T MR And Pseudo-color Technology In The Preoperative Evaluation Of Micro Vascular Decompression For Hemifacial Spasm

Objective To evaluate the application of 3.0T MR and pseudo-color technology in the preoperative evaluation of microvascular decompression for hemifacial spasm.Methods Retrospective analyzed 59 hemifacial spasm patients after microvascular decompression during period from Sep.2011 to Aug.2016.All cases hemifacial spasm undertook scanning in 3D-TOF-MRA and 3D-SPACE and processing the images by pseudo-color technology.Analyzed the imaging results and compared with the surgery findings.Results Analyzed the results before processing of pseudo-color technology.The positive ratio was 91.5%in the symptomatic sides and the non-symptomatic side was 1.7%..Analyzed the results after processing of pseudo-color technology.Neuro-vascular contact was found more frequently in the symptomatic sides(91.5%)than that in the non-symptomatic sides(1.7%).It increased the probability of discovery the offending vessels after processing of pseudo-color technology but no statistical significance(P>0.05).Compared with the surgery findings,the sensitivity and accuracy of images processing by pseudo-color technology for identifying offending vessels was 94.9%and 98.2%.All patients were found offending vessels compression the facial nerve in operation.The single offending vessel was identified in 39 cases as anterior inferior cerebellar artery,in 9 cases as posterior inferior cerebellar artery and in 3 cases as vertebral artery.Multiple offending vessels were less detected,containing anterior inferior cerebellar artery combined with vertebral artery in 6 cases,posterior inferior cerebellar artery combined with vertebral artery in 1 cases,and anterior inferior cerebellar artery combined with posterior inferior cerebellar artery in 1 cases.There was only 1 case among them inconsistent with the surgical results,whose offending vessel was preoperatively misdiagnosed as anterior inferior cerebellar artery,but was later confirmed as anterior inferior cerebellar artery combined with posterior inferior cerebellar artery in surgery.Conclusion Microvascular decompression is the most effective method for the treatment of hemifacial spasm.The application of preoperative imaging examination has a very important impact on the surgical efficacy.3D-TOF-MRA,3D-SPACE and pseudo-color technology could clearly display the relationship between the facial nerve and offending vessels,which played an important role in diagnosis of hemifacial spasm.