Useful of Three-dimensional Magnetic Rsonance Angiography and Constructive Interference in Steady State(CISS) Sequences in Patients with Hemifacial Spasm

Park, Chi Fu; Rhee, Bong Arm; Park, Jong Tae; Lim, Young Jin; Kim, Tae Sung; Leem, Won; Kim, Gook Ki

Abstract

We prospectively studied 100 patients to assess the usefulness of three-dimensional(3D) magnetic resonance(MR) angiography and constructive interference in steady state(CISS) sequences in patients with hemifacial spasm. Hemifacial spasm caused by tumors in the cerebellopontine angle was not included. 3D-short range MR angiography was performed in 50 patients, using FISP sequence. Compressive vessels were predicted in all 50 patients: anterior inferior cerebellar artery(AICA) in 23 cases, posterior inferior cerebellar artery(PICA) in 17 cases, vertebral artery(VA) and PICA in 5 cases, AICA and PICA in 3cases, VA in 1case, AICA and VA in 1case. In operative findings, offending vessels were identified in all cases : AICA in 22 cases, PICA in 17 cases, VA and PICA in 7 cases, AICA and PICA in 3 cases, VA & AICA in 1 case. Related degree of 3D-short range MR angiographic and operative findings was complete matching in 47(94.0%) cases, partial matching 2(4.0%) cases, and miss-matching 1(2.0%) case. MRI using CISS sequence was also performed in 50 patients. With this method, compressive vessels were also predicted in all 50 patients : AICA in 15 cases, PICA in 8 cases, VA in 6 cases, VA and PICA in 4 cases, AICA and PICA in 3 cases, VA and AICA in 2 cases. But, unknown compressive vessels were 12cases. In operative findings, vascular contact with the facial nerve root-exit zone(REZ) was present in all 50 cases. The vessels responsible were AICA in 20 cases, PICA in 14 cases, VA and PICA in 8 cases, VA in 3 cases, VA and AICA in 3 cases, AICA and PICA in 2 cases. Related degree of CISS images and operative findings was complete matching in 32(64.0%) cases, partial matching 5(10.0%) cases, and miss-matching 13(26.0%) cases. In conclusion, 3D-short range MR angiography and CISS are excellent and very useful for the preoperative evaluation of patients with hemifacial spasm, detection of not only the cause of hemifacial spasm but also identification of the compressive vessels and the relationship between compressive vessels and facial nerve REZ