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The Role of Functional MR Imaging in Patients with Ischemia in the Visual Cortex

 Young-Jun Lee  ;  Tae-Sub Chung  ;  Young Soo Yoon  ;  Myung Sik Lee  ;  Sueng-Han Han  ;  Gong Je Seong  ;  Kook Jin Ahn 
 AMERICAN JOURNAL OF NEURORADIOLOGY, Vol.22(6) : 1043-1049, 2001 
Journal Title
Issue Date
Adult ; Aged ; Cerebral Infarction/diagnosis* ; Cerebral Infarction/physiopathology ; Diagnosis, Differential ; Dominance, Cerebral/physiology ; Female ; Humans ; Ischemic Attack, Transient/diagnosis* ; Ischemic Attack, Transient/physiopathology ; Magnetic Resonance Angiography ; Magnetic Resonance Imaging* ; Male ; Middle Aged ; Reference Values ; Regional Blood Flow/physiology ; Visual Cortex/blood supply* ; Visual Cortex/pathology
BACKGROUND AND PURPOSE: Functional MR (fMR) imaging is based on changes in regional blood flow. The purpose of this study was to evaluate the role of fMR imaging for detection of a vascular compromised status in the occipital lobe in patients with ischemia in the visual cortex. METHODS: We performed fMR imaging in seven control subjects and seven patients with symptoms and signs of visual cortical transient ischemia and/or infarct. fMR imaging was performed using a gradient-echo sequence with the 2D fast low-angle shot technique. An axial slice including both visual cortices was selected, and stimulation of the visual cortex was performed using a red photostimulator. The number of activated pixels in each primary visual cortex area were counted and an asymmetry ratio [AR (%) = 100 x (R-L)/(R+L)/2] was calculated. Patients and control subjects underwent visual field examination, conventional MR imaging, and vascular imaging (MR angiography in all patients and control subjects, conventional catheter angiography in two patients). fMR imaging results were compared with the results of a visual field examination, conventional MR imaging, and vascular imaging. RESULTS: fMR imaging of the patients showed significant activation asymmetry (P <.05) compared with that of control subjects. Vascular abnormalities in the posterior circulation were found in all seven patients. By conventional MR imaging, five patients were found to have infarction in the occipital lobe and the remaining two patients showed no abnormality. In visual field examination, six of the seven patients showed homonymous hemi- or quadrantanopsia suggesting postchiasmic abnormalities, and the remaining patient had normal findings. fMR imaging showed decreased activity in the visual cortices corresponding to vascular abnormalities (seven of seven patients), permanent infarction (five of seven patients), or visual field defect (six of seven patients). Two patients with normal conventional MR imaging had vascular lesions in the posterior circulation, and fMR imaging showed decreased activity in the corresponding visual cortices. One patient with normal visual field examination had multifocal stenosis in the posterior cerebral artery without infarction, and fMR imaging showed decreased activity in the corresponding visual cortex. CONCLUSION: fMR imaging of the visual cortex may be a sensitive method for the detection of vascular-compromised status in the occipital lobe.
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1. College of Medicine (의과대학) > Dept. of Radiology (영상의학교실) > 1. Journal Papers
1. College of Medicine (의과대학) > Dept. of Ophthalmology (안과학교실) > 1. Journal Papers
Yonsei Authors
Seong, Gong Je(성공제) ORCID logo https://orcid.org/0000-0002-5456-4296
Chung, Tae Sub(정태섭)
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