Primary Hemifacial Spasm In MRI

Objective:Combining 3D-CISS and 3D-TOF-MRA sequences in MRI,we fully understand and apply the modified Hosaya scale to explore the relationship between vascular variation,responsible vessels and NVC and NVC image characteristics in patients with primary hemi-facial spasm.By adding oblique sagittal position to the scale,we refine and supplement the scale,and speculate the risk factors of disease,so as to provide early clinical diagnosis.And to improve the cure rate of surgical diseases to provide more image and anatomical information.Methods:39 patients with HFS were selected for routine craniocerebral MR plain scan,3D-TOF-MRA and 3D-CISS thin-layer scan.The magnification and window width of the images fixed with the same standard parameters were selected.Firstly,the relationship between bilateral auditory nerves and adjacent vessels was evaluated and recorded preliminarily according to the conventional image evaluation method and the improved Hosaya score standard.At the same time,the vertebral-basilar artery was recorded.Anatomical classification,measurement of the maximum width of bilateral facial nerve axes and coronal position,oblique sagittal facial nerve display longest level measurement of facial nerve length and brainstem angle(oblique sagittal)and longitudinal section of cistern area(horizontal plane of lower margin of cerebellum),oblique sagittal section perpendicular to the inner auditory meatus segment of facial auditory nerve.The degree of spasm and prognosis before and after operation were scored by two or more clinical assistant physicians.The patient’s medical history was recorded in detail and summarized into tables.SPSS 25 software package was used to complete the statistical test(including chi-square test and independent sample T test)between the patient group and the control group to make clear that there was no statistical significance.MVD was performed in all HFS patients.The follow-up period was 3-6 months(short-term).Results:1.Responsible vessels: 4 cases(11.1%),14 cases(38.89%)of pure AICA,9 cases(25%)of PICA,4 cases(11.1%)of VA and 5 cases(13.89%)of multi-vessel association were routinely displayed;12 cases(36.11%)of pure AICA were judged by modified Hosaya score,PICA was found in 8 cases(22.22%),VA in 5 cases(13.89%),BA in 1 case(2.8%)and multiple vessels in 10 cases(27.78%).2.Routine examination showed that 32 cases(88.89%)of spastic side were closely related to peripheral blood vessels,4 cases(11.1%)had no relationship with peripheral blood vessels,5 cases(13.89%)had no relationship with non-spastic side and 31 cases(86.11%)had no relationship with peripheral blood vessels(P < 0.01);32 cases(88.89%)had neuro-vascular compression/root contact,4 cases(11.11%)were suspicious according to the modified Hosaya scoring criteria;and no symptomatic contralateral nerve and blood vessels were suspicious.Compression or contact was found in 11 cases(30.55%),suspicious and untouched in 25 cases(69.44%)(P < 0.01).3.The results of MR imaging of 36 patients with HFS were compared with those of surgery: 31 patients with HFS were shown to be true positive,3 false positive,1 false negative and 1 true negative,respectively.The sensitivity of NVC was 96.87%,specificity was 25%,accuracy was 88.89%,positive predictive value was 91.18%,negative predictive value was 50%,Yoden index was 0.22;34 patients with HFS were shown to be true positive,1 false positive and 1 true negative,and 0 false negative by improved Hosaya score.The sensitivity,specificity,accuracy,positive predictive value,negative predictive value and Yoden index of NVC were 100%,50%,97.22%,97.14%,100% and 0.5respectively.4.The morphology of the responsible vessels was loop-shaped in 29 cases,including11 cases of loop-shaped combined sandwich type,1 case of loop-shaped combined series type,17 cases of single loop type,6 cases of concomitant/tangent type and 1 case of single sandwich type.5.Vertebral artery anatomical classification: 3 cases(8.3%)were type A,6 cases(16.67%)were type B1,3 cases(8.3%)were type B2,15 cases(41.67%)were type C1,6cases(16.67%)were type C2,and 3 cases(8.3%)were type D.Statistical analysis showed that HFS vertebral artery spastic lateral deviation was significantly different(P < 0.01).6.The oblique sagittal facial nerve showed that 63.89%(23/36)of the cistern was spastically wider than non-spastically,11.1%(4/36)was basically symmetrical and 25%(9/36)was narrower than non-spastically.Statistical analysis showed that the cistern width of HFS was significantly different from that of the control group(P=0.002),and the cistern size was basically asymmetrical.7.The angular data of spastic side and non-spastic side were similar to that of brainstem.The median angular value of non-spastic side was 108.75 degrees,and that of spastic group was 105.23 degrees.The results of Mann-Whitney U test showed that there was no significant difference between the brainstem angle of the affected side and that of the control group(U=510,Z=-1.554,P=0.12>0.05);the length of spastic side was not significantly different from that of the non-spastic-side(U=510,Z=-1.554,P=0.(P=0.32>0.05);the average length of spastic lateral nerve was 21.49 mm,and the average length of healthy lateral nerve was 20.89 mm.The length of affected and healthy lateral nerve was 21.49 +2.46 mm and 20.89 +2.67 mm,respectively.There was no significant difference between the length of affected and non-spastic lateral nerve.8.The supplement to the improved Hosaya scoring standard is in good agreement with the original standard,kappa = 0.891,0.8 < kappa < 1.Conclusion:1.The results suggest that 3D-CISS,3D-TOF-MRA combined with multi-directional thin-layer reconstruction is a good imaging method for the diagnosis of HFS.It can more sensitively display the relationship between the cistern segment of facial nerve and peripheral blood vessels,and determine the source of responsible blood vessels,thus providing reliable imaging data for the accurate diagnosis and preoperative pre-evaluation of primary HFS.2.The application of the improved Hosaya scoring standard in HFS has played an important role in guiding the radiologists and neurosurgeons,improving the sensitivity and specificity of lesion detection.This study has proved that there is a significant difference between the affected side and the non-spastic side of vascular compression in patients with hemifacial convulsion.The deviation of the affected side of vertebral artery is related to hemifacial spasm.3.The experimental results showed that the length and angle of bilateral cisterns were asymmetrical in HFS patients,and there was no statistical significance.The improved Hosaya score with refined supplements had excellent consistency and high degree of surgical anastomosis,which further confirmed the value of oblique sagittal position in displaying the adjacent relationship between nerves,nerves and blood vessels,and was worthy of wide application in clinical work.