[Detailed magnetic resonance imaging of abducens nerve by 3D-CISS].

Although abducens nerve palsy is a relatively common disease, the abducens nerve has been almost impossible to identify, because it is one of the finest cranial nerves and runs three-dimensionally in the prepontine cistern. Three-dimensional constructive interference in steady state (3D-CISS) is helpful in visualizing fine structural elements in the central nervous system because of its higher spatial resolution and fewer artifacts from cerebrospinal fluid. In this study, we successfully visualized the abducens nerve using 3D-CISS. The procedures were as follows: first, Dorello's canal and the ponto-medullary sulcus were identified as visible landmarks, and then the abducens nerve was followed to the root exit zone; second, the gray scale of the original image was inverted to clearly visualize the cisternal course of the nerve and the neighboring small vessels; and, finally, the entire cisternal course of the nerve was visualized in the same images in both oblique axial and oblique sagittal planes by a multi-planar reconstruction method. This reliable technique can be performed for the diagnosis of abducens nerve palsy.

[Treatment of subarachnoid hemorrhages in an isolated mountainous area].

From January 1997 to December 2001, patients with subarachnoid hemorrhage (SAH) among 14,008 residents in an isolated mountainous area; Oguni and Minamioguni towns in Kumamoto Prefecture, were evaluated. The subjects were patients being treated at Oguni Municipal Hospital. Over a period of 5 years, 19 patients were found to be suffering from SAH in this area, 3 of whom were visitors (residing outside this area). The annual incidence rate of SAH in this area was calculated as 22.9 per 100,000. The sex ratio (men:women) was 4:12. The average age was 67.9 years; 65.0 years for men and 68.8 years for women. Eleven patients were older than 65, and constituted 68.8% of the subjects. The risk factors of SAH were recognized, and both hypertension and smoking constituted 31.6%. Alcohol was 21.1% and hyperlipemia was 15.8%. In 13 clipping operated cases excluding 1 test craniotomy, Hunt & Kosnik's Grades at admission were G.I: 2, G.II: 5, G.III: 3, G.IV: 2 and G.V: 1, and Fisher's Groups were G.I: 0, G.II: 8, G.III: 3 and G.IV: 2. The sites of 16 operated aneurysms were internal carotid-posterior communicating artery (IC-PC): 2, anterior communicating artery (A Co.A): 4, middle cerebral artery (MCA): 10 and vertebral artery-basilan artery (VA-BA): 0. The aneurysmal size were < 5 mm: 5, 6-10 mm: 9 and 11 mm < :2 (average 7.6 mm, 2-15 mm). The results were evaluated at discharge, excluding 1 SAH of unknown etiology. 9 were good, 2 were dependent and 7 including 5 non-operative cases had died. We were satisfied with these results, because we were treating older patients. Although we attempted the clipping operation using only a three dimensional computed tomographic angiograply (3D-CTA; X-Vision GX (TOSHIBA) & X-Tension), we had no problem, except for 1 test craniotomy. 3D-CTA was useful during the clipping operation in the small hospital, especially, in regard to cost.