Figure 33-4. In perfusion imaging, a time-intensity curve (A) is generated by measurement of the passage of contrast material through brain tissue. The slope of the curve represents blood flow and the area under the curve represents blood volume. Voxel measurements of these parameters are converted to color maps showing blood flow, volume, and contrast transit time throughout the brain. Arterial occlusions alter the time-intensity curve by either flattening the slope of the curve or reducing the area under the curve. As an example, an acute occlusion of the proximal segment of the right middle cerebral artery produces a region of signal abnormality on diffusion-weighted imaging (B) that is matched in size by an area of reduced blood volume (C). This area represents infarcted tissue. The area of prolonged transit time (D) affects a larger territory, particularly posteriorly. The difference between this territory and the infarcted zone represents the ischemic penumbra, and is often referred to as the diffusion-perfusion mismatch.
AREA FOR CONTRAVERSIONOF EYES AND HEADAnt. parietal AMOTORSENSORYPost. parietal AAngular AVISUALCORTEXPost. temporal AAnt. temporal ATemporal polar AMiddle cerebral stemSup. division ofmiddle cerebral APrerolandic ABROCA AREA(MOTOR APHASIA)Inf. division ofmiddle cerebral ALateralorbito-frontal ALateral geniculate bodyAUDITORY AREAWERNICKE AREA(SENSORY APAHSIA)PO = PARIETAL OPERCULUM         (CONDUCTION APHASIA)PPR = POST. PARIETAL REGION           (ALEXIA WITH AGRAPHIA)Rolandic APPR  VISUAL RADIATION MOUTHHIPTRUNKHANDSFINGERSTHUMBFACETONGUELIPSARMPO
Figure 33-5. Diagram of the left cerebral hemisphere, lateral aspect, showing the courses of the middle cerebral artery and its branches and the principal regions of cerebral localization. Below is a list of the clinical manifestations of infarction in the territory of this artery and the corresponding regions of cerebral damage.
Figure 33-6. Diagram of one cerebral hemisphere, coronal section, showing the regions of blood supply of the major cerebral vessels.
Figure 33-7. A. Diagram of the right cerebral hemisphere, medial aspect, showing the branches and distribution of the anterior cerebral artery and the principal regions of cerebral localization. Below is a list of the clinical manifestations of infarction in the territory of this artery and the corresponding regions of cerebral damage. Also shown is the course of the main branch of the posterior cerebral artery on the medial side of the hemisphere. Note: Hemianopia does not occur; transcortical aphasia occurs rarely (isolation of the language areas) (see Chap. 22). B. Axial diffusion-weighted MRI showing an acute ischemic infarction in the anterior cerebral artery territory.
Figure 33-8. Corrosion preparations with plastics demonstrating penetrating branches of the anterior and middle cerebral arteries. The medial and lateral lenticulostriate arterioles are labeled, along with the recurrent artery of Heubner. (Reproduced by permission from Krayenbühl and Yasargil.)