Letter to the Editor Cerebrovasc Dis 2003;16:452–453 DOI: 10.1159/000072575 Hemiplegia in Posterior Cerebral Artery Occlusion: Acute MRI Assessment A. Montavont a, N. Nighoghossian a, c, M. Hermier b, c, L. Derex a, c, Y. Berthezène c, E. Philippeau a, J. Honnorat a, J.C. Froment b, c, L.R. Caplan d, P. Trouillas a a Cerebrovascular Disease Center, b Department of Radiology, c Creatis UMR 5515, CNRS, Lyon, France; d Beth Israel Deaconess Medical Center, Boston, Mass., USA Diffusion (DWI)- and perfusion-weighted MRI sequences [1] may assess the physiopathology of proximal posterior cerebral artery (PCA) occlusion mimicking proximal middle cerebral artery ischemia (MCA). Here we report 4 patients with proximal PCA occlusion who had an acute MRI assessment. These 4 patients (3 women/1 man, mean age 75, range 67–81 years) underwent MRI [2] within the first 6 h after the onset of symptoms. Patients received intravenous recombinant tissue plasminogen activator (0.8 mg/kg body weight) after MRI completion [3]. MRI was repeated on day 1. The National Institutes of Health Stroke Scale score (NIHSS) was performed at baseline and on day 1. Modified Rankin Scale score was assessed at 3 months. Hemiplegia was not associated with symptoms indicating a midbrain lesion. A conjugate deviation of the head and eyes was present in all cases. A poor outcome was observed in 3 patients who had persistent occlusion on day 1. Hemiplegia was mainly due to cerebral peduncle ischemia. PWI showed a large perfusion defect within the entire PCA territory and mild damage on DWI, thus contributing to a significant mismatch. MRI data are listed in table 1, and MRI data of case 2 are illustrated in figure 1. Case 2, an 81-year-old man with a history of atrial fibrillation, was admitted for sudden left hemiplegia. On admission, he had left hemiplegia, left HH, and left conjugate gaze palsy. The NIHSS score was 13. MRA showed a right proximal PCA occlusion and a large perfusion defect. DWI revealed ischemic damage within the right inferomesial temporal cortex. Intravenous recombinant tissue plasminogen activator was initiated 4 h 40 min after the onset of symptoms. On day 1, the NIHSS score was 22. MRA showed a persistent occlusion. Lesions on DWI involved the right, cerebral peduncle, posteromedial thalamus and occipitotemporal lobe. At 3 months, the modified ranking score was 4. The distinction between MCA and PCA territory infarction is difficult when the hemiplegia is not associated with symptoms indicating a midbrain lesion [4]. Hemiparesis results usually from infarction of the cerebral peduncle and less frequently from the anterior segment of the posterior limb of internal capsule involvement. The short circumflex arteries Table 1. MRI data Stroke MRI data on day 1 Case No. Baseline stroke MRI data IC MRA lesions on PWI lesions on DWI IC MRA additional lesions on DWI 1 R proximal PCA occlusion whole R PCA territory R posterior limb of internal capsule (ventral anterior thalamic nucleus) R inferomesial temporal cortex recanalization R medial surface of occipital lobe 2 R PCA/R VA occlusion whole R PCA territory R PICA territory R inferomesial temporal cortex R persistent PCA occlusion R cerebral peduncle R posteromedial thalamus R occipitotemporal lobe 3 L proximal PCA occlusion whole L PCA territory L medial thalamus L temporal lobe L paramedian midbrain L persistent PCA occlusion L cerebral peduncle L occipital lobe 4 R proximal PCA occlusion whole R PCA territory R medial thalamus R paramedian midbrain R persistent PCA occlusion bilateral medial thalami bilateral paramedian midbrain R = Right; L = left; VA = vertebral artery; PICA = posterior inferior cerebellar artery; IC = intracranial; VA = vertebral artery. ABC Fax + 41 61 306 12 34 E-Mail karger@karger.ch www.karger.com © 2003 S. Karger AG, Basel Accessible online at: www.karger.com/ced Fig. 1. MRI in patient 2: on day 0 MRA showed proximal occlusion of the right PCA, PWI a large perfusion defect involving the right PCA territory and DWI ischemic damage within the right inferomesial temporal cortex; on day 1 MRA indicated persistent occlusion of the right PCA, PWI a similar perfusion defect within the right PCA territory and DWI additional ischemic damage within the right cerebral peduncle. originate from the proximal segment of the PCA and send branches to the cerebral peduncle [5]. Acute lesion size on DWI does not correlate with acute NIHSS score [6]. Conversely, PWI showed in all cases a large perfusion defect within the entire PCA territory. Accordingly, the location of the vascular lesion, and the extent of the perfusion defect may provide useful information. References 1 Caplan L: Posterior circulation ischemia: Then, now, and tomorrow. The Thomas Willis Lecture-2000. Stroke 2000;31:2011–2023. 2 Nighoghossian N, Hermier M, Adeleine P, Derex L, Dugor JF, Philippeau F, Ylmaz H, Honnorat J, Dardel P, Berthezène Y, Froment JC, Trouillas P: Baseline magnetic resonance imaging parameters and stroke outcome in patients treated by intravenous tissue plasminogen activator. Stroke 2003; 34:458–464. Letter to the Editor 3 Trouillas P, Nighoghossian N, Derex L, et al: Thrombolysis in a series of 100 cases of acute carotid territory stroke with intravenous tissue plasminogen activator. Determination of etiological, topographical and radiological outcome factors. Stroke 1998;29:2529–2540. 4 Hommel M, Besson G, Pollak P, Kahane P, Le Bas JF, Perret J: Hemiplegia in posterior cerebral artery occlusion. Neurology 1990;40:1496–1499. 5 Zeal AZ, Rothon AL: Microsurgical anatomy of the posterior cerebral artery. J Neurosurg 1978;48:534–559. 6 Linfante I, Llinas R, Schlaug G, Chaves C, Warach S, Caplan L: Diffusionweighted imaging and National Institute of Health Stroke Scale in the acute phase of posterior-circulation stroke. Arch Neurol 2001;58:621–628. Prof. N. Nighoghossian Hôpital Neurologique et Neurochirurgical Pierre-Wertheimer 59, boulevard Pinel, FR–69003 Lyon (France) Tel. +334 72 35 78 10, Fax +334 72 35 78 06 E-Mail norbert.nighoghossian@chu-lyon.fr 453 Copyright: S. Karger AG, Basel 2003. Reproduced with the permission of S. Karger AG, Basel. Further reproduction or distribution (electronic or otherwise) is prohibited without permission from the copyright holder.