Radiological Imaging of Cerebral Vasculature
Cerebral vessels can be observed in vivo using cerebral angiography. First, radiopaque material is injected into either the anterior or the posterior arterial system. Then a series of skull x-ray fims are taken in rapid repetition as the material circulates. films obtained while the radiopaque material is within cerebral arteries are called angiograms. Films obtained later, after the radiopaque substance has reached the cerebral veins or the dural sinuses, are called venograms. The entire course of the internal carotid artery is shown in cerebral angiograms in figure 4-9. Images can be obtained from different angles with respect to the cranium. Two views are common -from the front (frontal projections) and from the side (lateral projections). The lateral view shows the c-shape of the anterior cerebral artery (and it's branches). The medial-to-lateral course of the middle cerebral artery is revealed in the frontal view.
The rostrocaudal course of the middle cerebral artery, from the point at which it enters the lateral sulcus to the point at which it emerges and distrubutes over the lateral surface of the cerebral cortex, is revealed in the lateral view. The middle cerebral artery forms loops at the dorsal junction of the insular cortex and the opercular surface of the frontal and parietal lobes. These loops serve as radiolgocial landmarks that aid in estimating the position of the brain in relation to the skull. figure 4-10 shows the posterior circulation viewed from a lateral perspective. two vertebral arteris joining to form the basilar arteyer and the subsequent bifurcation of the basilar artery into the two posterior cerebral arteries.
Cerebral angiography involves intravascular injection of radiopaque material. The process of injecting this material, and the material itself, can produce neurological complications; therefore, its use is not without risk. Recently, magnetic resonance imaging ahas been applied to the study of brain vasculature because it can detewct motion of water molecules. This application, termend magnetic resonance angiography (MRA), selectively images blood in motion.
The rostrocaudal course of the middle cerebral artery, from the point at which it enters the lateral sulcus to the point at which it emerges and distrubutes over the lateral surface of the cerebral cortex, is revealed in the lateral view. The middle cerebral artery forms loops at the dorsal junction of the insular cortex and the opercular surface of the frontal and parietal lobes. These loops serve as radiolgocial landmarks that aid in estimating the position of the brain in relation to the skull. figure 4-10 shows the posterior circulation viewed from a lateral perspective. two vertebral arteris joining to form the basilar arteyer and the subsequent bifurcation of the basilar artery into the two posterior cerebral arteries.
Cerebral angiography involves intravascular injection of radiopaque material. The process of injecting this material, and the material itself, can produce neurological complications; therefore, its use is not without risk. Recently, magnetic resonance imaging ahas been applied to the study of brain vasculature because it can detewct motion of water molecules. This application, termend magnetic resonance angiography (MRA), selectively images blood in motion.