MR Imaging and IVIR Angiography in Patients with Hemifacial Spasm

PURPOSE: To determine the usefulness of MR imaging and MR angiography (MRA) in the evaluation of patients with hemifacial spasm. MATERIAL AND METHODS: One hundred and twenty-five patients with hemifacial spasm were included in this study. Axial T1-, T2-weighted images, proton density image (3mm thickness, 256 x 192) and 3-D TOF MRA were performed. Relation between facial nerve and adjacent arterial structures was carefully evaluated, which was correlated with surgical findings. RESULTS: MRA identified the presen(~e of offending vessels at the root exit zone of facial nerve and its origin in 117 patients(52 PICA, 50 AICA, 6 vertebral artery, 9 dual vessels). There were 4 false negatives and 4 false positives. Vascular groove at the root exit zone was identified in 52 cases, but there was no positive correlation between severity and duration of symptoms. The presence of ipsilateral or contralateral distal loop formation of vertebral artery were noted in 63 patients. In addition, 4 cases of neoplastic and vascular lesions were also demonstrated on MR imaging. CONCLUSION: Combination of MR imaging and MRA is an useful screening modality in the presurgical evaluation of hemifacial spasm, which can demonstrate the offending vessels as well as other pathologic lesions.

The Relationship between ST-T Electrical Alternans on EKG and Ventricular Arrhythmia

In order to observe the development of ventricular arrhythmia during regional myocardial ischemia and reperfusion, especially under the presence or absence of ST-T electrical alternans on epicardial EKG. The proximal left descending coronary artery(LAD) was ligated for 20 minutes and then reperfused suddenly in twenty-three cats. Standard lead EKG(Lead??, chest lead EKG and epicardial lead EKG were recorded simultaneously during the occlusion and reperfusion respectively. During the ligation of LAD, STEA was observed in thirteen cats(56.5%). In occlusion period, the incidence of ventricular tachycardia in STEA positive group was significantly higher than in the negative group(p<0.01) and arrhythmic score was significantly higher(p<0.005) also In the reperfusion period the incidence of vefntricular fibrillation in STEA positive group was significantly higher than in the negative group(p<0.025). But there was the tendency to be higher in arrhythmic score of STEA positive group. There were no differences in heart rate, systolic left ventricular pressure, ST elevation and ST width in both groups. Most forms of ST-T of sinus rhythm before and after development of ventricular premature beat was low form(L). It was concluded that at the presence of STEA on EKG, the incidence of ventricular arrhythmia was more prevalent. So, STEA can be available as a marker of ventricular arrhythmia and prognostic factor.