Vascular Medullary Streaks in a Patient With Atherosclerotic Internal Carotid Artery Occlusion: Case Report Chiaki Mikami, M.D., Takashi Inoue, M.D., Kuniaki Ogasawara, M.D., and Akira Ogawa, M.D. Department of Neurosurgery, Iwate Medical University School of Medicine, Morioka, Iwate, Japan Mikami C, Inoue T, Ogasawara K, Ogawa A. Medullary streaks in a patient with atherosclerotic internal carotid artery occlusion: case report. Surg Neurol 2004;62:42– 44. BACKGROUND Magnetic resonance imaging (MRI) of a patient with atherosclerotic internal carotid artery (ICA) occlusion demonstrated medullary streaks in the deep white matter, which were previously observed only in moyamoya disease and may indicate decreased cerebral blood flow. Cerebral perfusion and metabolism were evaluated using positron emission tomography (PET). CASE DESCRIPTION A 46-year-old man presented with right hemiparesis and motor aphasia. Cerebral angiography showed left cervical ICA occlusion. MRI showed medullary streaks in the deep white matter of the left middle cerebral artery (MCA) territory. PET imaging of this region revealed decreased cerebral blood flow and increased oxygen extraction fraction and cerebral blood volume. MRI after superficial temporal artery-MCA anastomosis revealed decreased intensity of the medullary streaks. streaks are more obvious in regions with decreased cerebral blood flow (CBF) and may be caused by dilation of the medullary vessels [7]. We treated a patient with atherosclerotic internal carotid artery (ICA) occlusion, who had medullary streaks on MRI. Cerebral perfusion and metabolism were also investigated using positron emission tomography (PET). Case Report A 46-year-old man in good health suffered right hemiparesis and motor aphasia, and was admitted CONCLUSIONS Medullary streaks in patients with atherosclerotic ICA occlusion may indicate reduced perfusion pressure and increased risk of recurrent stroke. © 2004 Elsevier Inc. All rights reserved. KEY WORDS Atherosclerotic disease, internal carotid artery occlusion, medullary streak, magnetic resonance imaging, positron emission tomography. agnetic resonance imaging (MRI) of patients with moyamoya disease frequently demonstrate transverse lines in the white matter, which are called medullary streaks [7]. These medullary M Address reprint requests to: Takashi Inoue, M.D., Department of Neurosurgery, Iwate Medical University School of Medicine, 19-1 Uchimaru, Morioka, Iwate 020-8505, Japan. Received March 4, 2003; accepted August 6, 2003. 0090-3019/03/$–see front matter doi:10.1016/j.surneu.2003.08.015 1 MRI showing medullary streaks (arrows) in the deep white matter of the left MCA territory. © 2004 Elsevier Inc. All rights reserved. 360 Park Avenue South, New York, NY 10010 –1710 Medullary Streaks in ICA Occlusion 2 Surg Neurol 2004;62:42– 44 43 PET images showing decreased rCBF and increased rOEF and rCBV in the left MCA territory (arrows). to our department. Neurologic examination revealed right hand weakness. Computed tomography (CT) of the brain confirmed small infarcts in the left white matter. Cerebral angiography showed left cervical ICA occlusion. The territories of the anterior and middle cerebral arteries (ACA and MCA) were perfused via leptomeningeal anastomoses from the contralateral ACA and ipsilateral posterior cerebral artery. MRI was performed with a Signa VH/i 3.0 Tesla scanner (General Electric Systems, Milwaukee, WI). Fast spin echo images were used for proton densityweighted imaging with the following parameters: repetition time 4000 ms, echo time 21 ms, matrix 512 ⫻ 384, field of view 240 mm, and slice thickness 6 mm. After conventional 2-D Fourier transformation, the gray scale of the images was inverted and given an expanded window range (T2R) [3]. Axial MRI showed medullary streaks in the deep white matter of the left MCA territory (Figure 1). Regional CBF (rCBF), regional cerebral blood volume (rCBV), and regional oxygen extraction fraction (rOEF) were measured in separate passes using a 4-ring, seven-slice PET scanner, with in-plane and axial resolutions of 8 and 10 mm, respectively. rCBF was calculated using an autoradiographic method with 90-second scanning after IV administration of 1110 MBq of 15O-labeled water. rOEF was measured using an 15O steady-state model with 1-minute inhalation of 6105 MBq/min of 15O-labeled molecular oxygen. CBV was measured after 1 minute of inhalation of 5180 MBq/min of 15O-labeled carbon monoxide (C15O gas). rOEF was calculated after CBV correction based on the C15O gas inhalation data [8]. Decreased rCBF and increased rCBV and rOEF were detected in the left MCA territory on the PET images (Figure 2). The patient underwent left superficial temporal artery-MCA anastomosis. MR imaging 2 months after surgery revealed significant decrease in the intensity of the medullary streaks (Figure 3). Discussion The present case of atherosclerotic ICA occlusion was associated with medullary streaks in the deep white matter of the left MCA territory on preoperative MR imaging, as well as decreased rCBF and increased rOEF and rCBV on PET images. Medullary streaks in patients with moyamoya disease may increase in intensity with decreased rCBF on single photon emission computed tomography [7]. On the other hand, rCBV may increase to compensate for reduced rCBF in patients with atherosclerotic ICA occlusion [1,2,4,13]. rCBV increases as a result of increased microanastomosis and compensatory vasodilation following decreased perfusion pressure [5,9,11,12]. Therefore, the medullary streaks observed in our patient may indicate vasodilation because of decreased perfusion pressure. Medullary streaks, which were previously detected only in patients with moyamoya disease, may also be observed in patients with atherosclerotic ICA occlusion and reduced perfusion pressure. Decreased perfusion pressure is associated with a higher risk of subsequent ischemic stroke 44 Surg Neurol 2004;62:42– 44 Postoperative MRI showing decreased intensity of the medullary streaks in the deep white matter of the left MCA territory. 3 [6,10,14], so medullary streaks on high-field MRI may indicate the risk of recurrent stroke. This work was supported in part by Grants-in-Aid for Advanced Medical Science Research from the Ministry of Education, Culture, Sports, Science, and Technology, Japan. REFERENCES 1. Derdeyn CP, Grubb RL Jr., Powers WJ. Cerebral hemodynamic impairment: methods of measurement and association with stroke risk. Neurology 1999;53: 251–9. 2. 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Taki W, Yonekawa Y, Kobayashi A, et al. Cerebral circulation and metabolism in adults’ moyamoya disease–PET study. Acta Neurochir (Wien) 1989;100: 150 –4. 14. Yamauchi H, Fukuyama H, Nagahama Y, et al. Evidence of misery perfusion and risk for recurrent stroke in major cerebral arterial occlusive diseases from PET. J Neurol Neurosurg Psychiatry 1996;61:18 – 25. COMMENTARY On rare and random occasions an anecdotal case appears that changes medicine. The present popular notion that collecting of medical data leads to advancements can be disappointing if it does not have a good background of clinical experience. This case sets the gold standard for evaluating cases of internal carotid artery occlusion. If high field MR or PET studies are not available, physicians should make the community aware that quality medicine is not possible without advances in technology. Without these advances physician groups should request reduction of malpractice costs of the insurance carriers. Insurance carriers are in a position to change these technical limitations. Glen D. Dobben, M.D. Department of Radiology University of Illinois at Chicago Chicago, Illinois