Vascular Diseases of the Central Nervous System

STROKE SYNDROME

• The term “STROKE” denotes the sudden and dramatic development of a focal neurologic deficit, which may vary from dense hemiplegia (paralysis on one side of the body) and coma only a trivial neurologic disorder.

• Stroke also known as acute brain infarction, most commonly involves the circulation of the internal carotid arteries and is seen with symptoms that include acute “hemiparesis” (weakness of one side of the body) and “dysarthria” (difficulty in speaking).

RADIOGRAPHIC APPEARANCE

• CT (initial exam) – a triangular or wedge – shaped hypodensity on noncontrast scan

• MRI – T2-weighted image produced high signal intensity of vascular territory involve

• Diffusion-weighted MRI – hyperintense signals within 2 hours of onset

• CT/MRI – mass effect seen 7-10 days after onset.

LOCATION

• Neurologic deficit due to lack of circulation; internal carotid artery most common site.

TREATMENT

• Bed rest and reduced external stimuli for all stroke victims. Medications to treat increased intracranial pressure if symptoms arise. Patients with thrombotic strokes receive anticoagulants and possibly thrombolytic agents.

Transient Ischemic Attacks

• TIAs present as focal neurologic deficits that completely resolve within 24 hours. They may result from emboli originating from the surface of an arteriosclerotic ulcerated plaque (embolic stroke), which causes temporary occlusion of cerebral vessels, or from stenosis of an extracerebral artery, which leads to a reduction in critical blood perfusion.

RADIOGRAPHIC APPEARANCE

LOCATION

• The most common location of surgically treatable arteriosclerotic disease causing TIAs is the region of carotid bifurcation in the neck.

• In patients with an asymptomatic bruit (a rumbling noise heard by stethoscope) or an unclear history of a TIA, carotid duplex color-flow Doppler scanning is often the initial screening study.

• In most cases, carotid duplex scanning when combined with MRA can reliably determine whether the extent of the diseases is sufficient to warrant more invasive pocedures (angiography).

• High-resolution, real-time ultrasound techniques provide hemodynamic information about blood flow velocity. Using ultrasound techniques, it may be possible to differentiate patients with a total occlusion of the internal carotid artery from those with a tiny residual lumen.

• Noninvasive MRA provides accurate imaging of the carotid bifurcation and it demonstrates narrowing of the vertebral arteries.

TREATMENT

• Accurate diagnosis and appropriate treatment (antiplatelet therapy, anticoagulation therapy, or carotid endarterectomy) are essential to prevent permanent deficits. Thrombolytic agents may lso be used.

Intraparenchymal Hemorrhage

• Aside from HEAD TRAUMA, the principal cause of INTRAPARENCHYMAL HEMORRHAGE is hypertensive vascular disease.

• Less frequent causes are rupture of acongenital berry aneurysm oran arteriovenous malformation.

• Hypertensive hemorrhages results in oval r circular collections thatvsmdisplace the surrounding brain and can cause a significant mass effect.

• Hypertensive Hemorrhage are most frequent in BASAL GANGLIA, WHITE MATTER, THALAMUS, CEREBELLAR HEMISPHERS , AND PONS.

• INTRAPARENCHYMAL HEMORRHAGES resulting from congenital berry (saccular) aneurysms usually are associated with subarachnoid hemorrhage and tend to develop in regions where these congenital vascular anomalis most commonly occur. Include the sylvian fissurr and the midline subfontal area.

RADIOGRAPHIC APPERANCE

LOCATION

• It should be evaluated with MRI or a noncontrastCT scan.

• On CT - fresh hematoma appears homogeneously dense, well defined lesionwith a tound to oval configuration.

• Cobtrast enhancement usually develops about the periphery of hematoma after 7-10 days.

• On MRI - an aneurysm produces a flow void on both T1 AND T2 -wieghted images.

• CTA & MRI can visualize large and medium anuerysms, along with feeding and draining vesseks associated with an arteriovenous malformation.

TREATMENT

• Steroid therapy, especially in nontraumatichematomas.

• In casebof hemorrhagic strokes, first line of treatment consists of stopping the bleeding , and second is to try to prevent a recurrence of bleeding, and finally surgery.

• For aneurysm ,SURGICAL PLACEMENT of a clip at the neck of the lesion .

• AVMs require sugery / neurointerventional procedures

Subarachnoid Hemorrhage

• A major cause of subarachnoid hemorrhage (hemorrhagic stroke) is rupture of a berry aneurysm. Patients with this condition usually have a generalized excruciating headache followed by unconsciousness.

RADIOGRAPHIC APPEARANCE

LOCATION• The most common locations for berry ane

urysms are the origins of the posterior cerebral and

• anterior communicating arteries and the trifurcation of the middle cerebral artery.

• Bleed beneath arachnoid layer of meninges

TREATMENT

• If emergency surgery within the first 72 hours after the hemorrhage is planned, emergency

• selective angiography is indicated. If surgical intervention is to be delayed, angiography should

• be postponed until just before surgery