![]() CTA also provides useful information for patients in therapeutic trials. 16ĬT angiography (CTA) is a precise technique for assessing the level of intracranial vascular occlusion in patients presenting within 6 hours of stroke onset (Fig. The hyperdense BA and subtle signs of hemorrhage must be carefully sought. Medial surface involvement is usually related to the P1 segment of the PCA, and Imaging WorkupĬomputed tomography (CT) results are commonly negative early in the course of ischemic brainstem stroke.14., 15. Small dorsal strokes are usually caused by occlusion of penetrating branches from the BA, whereas proximal PCA atherosclerosis is the usual pathogenic mechanism in lesions involving the anterior midbrain. Infarcts limited to the midbrain are uncommon and usually are accompanied by involvement of other structures such as the cerebellum, thalamus, and pons. The arterial blood supply to the midbrain is complex. ![]() 4) causes hemiparesis or Midbrain Infarction Ventral infarcts are the most common type of isolated pontine infarction (51%-58%) and result from occlusion of the anteromedial and the anterolateral arterial groups.10., 11.Īnteromedial infarct (Fig. ![]() 10 Atherosclerotic disease of perforating arteries and occlusion or stenosis of the BA are the most common causes of pontine infarct. Isolated pontine strokes are relatively frequent, but they can occur as part of a larger infarction in the posterior circulation (Table 1). 9 VA dissection is another important cause (20%-30%) of both LMI and MMI 8 and should be suspected in the context of neck pain and medullary symptoms, particularly in young patients. 8Ītherosclerosis of the VA and its branches is the most common cause of MI. Lateral MIs (LMIs) are 3-4 times more common than medial MIs (MMIs) there is a 3:1 male predominance. MIs account for 7% of all ischemic brainstem strokes. 5 Several risk factors are associated with this condition, including hypertension, fibromuscular dysplasia, 6 trauma, and spinal manipulation.īilateral distal vertebral occlusions cause low flow in the posterior circulation, leading to Medullary Infarction (MI) ![]() VA dissection is an increasingly described cause of brainstem infarct in patients younger than 45 years. Occlusion of the VA and its branches often occurs secondary to dissection or atherosclerosis and usually causes infarction in the medulla or inferior cerebellum. The anteromedial group arteries originate from the anterior spinal artery (ASA) caudally and the vertebral artery (VA) cranially the anterolateral group arteries also arise from the ASA and VA the lateral group arteries arise from the posterior inferior cerebellar artery and the posterior group arteries arise from the posterior spinal artery.Īt the level of the pons, we can differentiate 3 intrinsic Etiology Proper care or preventing these issues can greatly lower your risk of stroke.At the level of the medulla oblongata, 4 territories may be differentiated (Fig. Other factors that may increase your risk can be changed such as:Ĭertain medical issues can increase your risk of stroke. ![]() Race-People of African American, Hispanic, or Asian/Pacific Islander descent are at increased risk.Certain factors increase your risk of stroke, but can not be changed, such as: ![]()
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