- Department of Neurosurgery, Iwate Medical University, Morioka, Iwate, Japan
- Division of Ultra-High Field MRI and Department of Radiology, Iwate Medical University, Morioka, Iwate, Japan
Division of Ultra-High Field MRI and Department of Radiology, Iwate Medical University, Morioka, Iwate, Japan
DOI:10.4103/2152-7806.143760Copyright: © 2014 Sato Y. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
How to cite this article: Sato Y, Ogasawara K, Yoshida K, Sasaki M. Preoperative visualization of the marginal tentorial artery as an unusual collateral pathway in a patient with symptomatic bilateral vertebral artery occlusion undergoing arterial bypass surgery: A 7.0-T magnetic resonance imaging study. Surg Neurol Int 31-Oct-2014;5:157
How to cite this URL: Sato Y, Ogasawara K, Yoshida K, Sasaki M. Preoperative visualization of the marginal tentorial artery as an unusual collateral pathway in a patient with symptomatic bilateral vertebral artery occlusion undergoing arterial bypass surgery: A 7.0-T magnetic resonance imaging study. Surg Neurol Int 31-Oct-2014;5:157. Available from: http://sni.wpengine.com/surgicalint_articles/preoperative-visualization-of-the-marginal-tentorial-artery-as-an-unusual-collateral-pathway-in-a-patient-with-symptomatic-bilateral-vertebral-artery-occlusion-undergoing-arterial-bypass-surgery-a-7/
Background:Extracranial–intracranial arterial bypass surgery is rarely performed for recurrent or progressing stroke due to vertebrobasilar artery steno-occlusive disease. Non-enhanced 7.0-T magnetic resonance (MR) imaging reveals cerebral arteries more clearly than 3.0-T or less MR imaging.
Case Description:A 45-year-old man developed recurrent transient ischemic attacks due to hemodynamic ischemia caused by occlusion of bilateral vertebral arteries despite antiplatelet therapy. MR angiography with a 7.0-T imager demonstrated that each marginal tentorial artery ran along the tentorial edge and anastomosed with each posterior cerebral artery (PCA) as collateral circulation. Superficial temporal artery (STA)–superior cerebellar artery (SCA) or PCA bypass surgery was planned through a subtemporal approach. During surgery, the SCA was not visible when the tentorial edge was elevated. The tentorium was not cut, and the STA was anastomosed with the P2 segment of the PCA. Ischemic symptoms completely resolved after surgery.
Conclusions:Preoperative 7.0-T MR imaging visualized the marginal tentorial artery as an unusual collateral pathway in a patient with symptomatic bilateral vertebral artery occlusion undergoing arterial bypass surgery.
Keywords: 7.0-T MR imaging, arterial bypass surgery, collateral circulation, vertebral artery occlusion
Symptomatic vertebrobasilar artery steno-occlusive disease is commonly treated with antiplatelet drugs. However, the early risk of stroke recurrence in patients with such pathogenesis is high,[
In this report, we describe a case involving a patient with frequent ischemic attacks and hemodynamic brain ischemia caused by occlusion of bilateral vertebral arteries (VAs). Preoperative 7.0-T MR imaging demonstrated collateral circulation running along the tentorial edge that had not been identified on cerebral angiography with arterial catheterization. Based on this MR finding, we performed STA–posterior cerebral artery (PCA) anastomosis instead of STA–SCA anastomosis, which would have involved cutting the tentorium.
History and examination
A 45-year-old man presented with minor stroke appearing as symptoms of dizziness and defects of the visual field, and 0.5-T MR imaging showed an infarct in the right occipital lobe. Administration of an antiplatelet drug was initiated. Six months later, the patient experienced transient ischemic attacks manifesting as dizziness and disturbance of consciousness. MR imaging using a 1.5-T imager showed spotty new ischemic lesions in the right cerebellum, pons, and left thalamus. MR angiography with the same imager revealed occlusion of bilateral VAs.
Cerebral angiography with arterial catheterization showed occlusion at the V3 segments of bilateral VAs. On common carotid angiography, bilateral posterior communicating arteries, bilateral marginal tentorial arteries, and the upper part of the basilar artery were faintly visible [
Three-dimensional time-of-flight MR angiography with a 7.0-T imager (Signa 950; GE Medical Systems, Milwaukee, WI, USA) demonstrated that each marginal tentorial artery originating from each internal carotid artery ran along the tentorial edge and anastomosed with each PCA [
Maximum intensity projection of preoperative three-dimensional time-of flight magnetic resonance angiography using a 7.0-T imager and a 32-channel phased array coil for the brain to optimize signal detection with the image sequence from a spoiled gradient echo (repetition time, 12 ms; echo time, 2.9 ms; flip angle, 12°; matrix size, 512 × 512; field of view, 22 × 22 cm; slice thickness, 1.0 mm) revealing that each marginal tentorial artery originating from each internal carotid artery runs along the tentorial edge and anastomoses with each posterior cerebral artery (a). The right superior cerebellar artery is located below the right marginal tentorial artery (b)
Quantitative brain perfusion single-photon emission computed tomography (SPECT)[
Operation and postoperative course
The patient suffered frequent orthostatic dizziness and we planned STA–SCA or PCA bypass surgery using a subtemporal approach through a right temporal craniotomy. During surgery, the SCA was not visible when the tentorial edge was elevated, as expected from preoperative 7.0-T MR angiography [
Orthostatic dizziness completely resolved after surgery and postoperative angiography demonstrated that the entire posterior circulation was perfused via an anastomosed STA [
The patient discussed in this report suffered frequent ischemic attacks due to hemodynamic brain ischemia in the posterior circulation as detected on brain perfusion SPECT, and underwent vascular reconstructive surgery. The degree of atherosclerosis is usually greater in the proximal portion of the PCA than in the SCA,[
When the VAs are occluded bilaterally and collateral flow via the posterior communicating arteries is insufficient and, as a result, basilar arterial blood supply is tenuous, retrograde flow through the anterior spinal artery can provide collateral circulation.[
Several investigators have demonstrated that 7.0-T MR imaging visualized the perforating arteries as well as the large vessels of the circle of Willis or the first- and second-order branches in more detail than 1.5- or 3.0-T MR imaging.[
This work was partly supported by Grant-in-Aid for Strategic Medical Science Research (S1491001, 2014-2018) from the Ministry of Education, Culture, Sports, Science and Technology of Japan; JSPS KAKENHI Grant Number 2612345.
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