IMAGES IN NEUROLOGY Value of Perfusion Computed Tomography in Stroke Mimics P ERFUSION COMPUTED tomography (CT) is increasingly being used in the diagnosis and management of patients with strokelike symptoms. By providing information about the cerebral blood flow, volume, and mean transit time, the presence of ischemia can be determined and this can aid in clinical decision making, especially surrounding the use of thrombolytics. We evaluated an 81-year-old woman with atrial fibrillation and an old left hemispheric infarct for sudden onset of right-sided weakness and aphasia. Her eyes were midline. It was unclear if she had a new infarct or focal seizures. Plain CT revealed an old left lenticulostriate infarct without signs of acute stroke, and CT angiogram did not reveal major vascular occlusion. Perfusion CT revealed an increase in cerebral blood flow and cerebral blood volume and a de- crease in mean transit time in the left parieto-occipital and corona radiata areas (Figure 1). These findings were in keeping with hyperperfusion, rather than ischemia. Therefore, we did not treat her with thrombolytics. Electroencephalography did not reveal epileptic activity. Subsequent magnetic resonance imaging revealed the presence of enhancing lesions in the same areas (Figure 2). Brain biopsy confirmed the diagnosis of a malignant glioma. This case illustrates that perfusion CT can also be useful in diagnosing stroke mimics and determining clinical management. Other studies have shown that hyperperfusion can be seen in brain tumors and seizures.1,2 M. Mehdiratta, MD, FRCPC M. Selim, MD, PhD Correspondence: Dr Mehdiratta, Harvard Medical School, Beth Israel Deaconess Medical Center, (REPRINTED) ARCH NEUROL / VOL 64 (NO. 9), SEP 2007 1348 Stroke Division, 330 Brookline Ave, Palmer 127, Boston, MA 02215 (mmehdira@bidmc.harvard.edu). Author Contributions: Study concept and design: Mehdiratta and Selim. Acquisition of data: Mehdiratta and Selim. Analysis and interpretation of data: Mehdiratta and Selim. Drafting of the manuscript: Mehdiratta and Selim. Critical revision of the manuscript for important intellectual content: Mehdiratta and Selim. Administrative, technical, and material support: Mehdiratta. Study supervision: Selim. Financial Disclosure: None reported. REFERENCES 1. Eastwood JD, Provenzale JM. Cerebral blood flow, blood volume and vascular permeability of cerebral glioma assessed with dynamic CT perfusion imaging. Neuroradiology. 2003;45(6):373-376. 2. Wiest R, von Bredow F, Schindler K, et al. Detection of regional blood perfusion changes in epileptic seizures with dynamic brain perfusion CT—a pilot study. Epilepsy Res. 2006;72(2-3):102-110. WWW.ARCHNEUROL.COM ©2007 American Medical Association. All rights reserved. Downloaded From: http://archneur.jamanetwork.com/ by a University of St. Andrews Library User on 06/07/2015 A B 100 C 10 000 15 000 R R R 1 2 5 1 2 5 1 2 5 0 0 0 Figure 1. Perfusion computed tomography maps of cerebral blood flow (A), cerebral blood volume (B), and mean transit time (C) showing evidence of increased perfusion in the left parieto-occipital area (arrows). A B Figure 2. T1-weighted magnetic resonance images with gadolinium showing enhancement in the left corona radiata and parieto-occipital areas. Biopsy confirmed glioblastoma multiforme. (REPRINTED) ARCH NEUROL / VOL 64 (NO. 9), SEP 2007 1349 WWW.ARCHNEUROL.COM ©2007 American Medical Association. All rights reserved. Downloaded From: http://archneur.jamanetwork.com/ by a University of St. Andrews Library User on 06/07/2015