Role of CT Angiography in Patient Selection for Thrombolytic Therapy in Acute Hemispheric Stroke

Abstract

Background and Purpose-It has been shown that thrombolytic therapy can improve clinical outcome in a subgroup of patients with acute cerebral ischemia. This subgroup was characterized by certain clinical and imaging findings (eg, moderate to severe neurological deficit for less than 3 to 6 hours, occlusion of the middle cerebral artery, lack of extended infarct signs on CT, and efficient leptomeningeal collaterals). Although not part of published prospective randomized rtPA trials, information about the status of the brain vessels would be helpful in the selection of patients who may benefit the most. Our purpose was to determine the feasibility of CT angiography (CTA) in patients with acute hemispheric ischemia and to evaluate its relevance for thrombolytic therapy. Methods-CTA was performed in 40 consecutive patients (11 women and 29 men; age range, 19 to 80 years) with moderate or severe symptoms (National Institutes of Health Stroke Scale score of Ն8) of acute hemispheric ischemia. CTA findings were compared with Doppler ultrasonography (US; nϭ22) and intra-arterial digital subtraction angiography (DSA; nϭ7). Twenty patients received thrombolytic therapy, the remaining patients received intravenous heparin. Results-Images and 3-dimensional reconstructions of diagnostic quality could be obtained in all patients. Thirty-four patients had a vessel occlusion. The extent of leptomeningeal collaterals correlated significantly with the outcome after thrombolytic therapy (r s ϭ0.46, PϽ0.05). The evaluation of diagnostic accuracy showed a high agreement with US (22 of 22) and DSA (6 of 7). Conclusions-CTA can provide important information for the initiation of therapy in patients with acute hemispheric ischemia. Identification of patients with autolyzed thrombi, occlusion of the internal carotid artery bifurcation, and poor leptomeningeal collaterals is feasible with the use of CTA. These patients may have little potential for benefit from thrombolytic therapy. (Stroke. 1998;29:935-938.)

Systematic Review of Methods for Assessing Leptomeningeal Collateral Flow

“…10,11,28,49,50 Seven grading scales by using CTA were identified, with LMF assessments performed on 593 patients with suspected acute stroke (Table 3). 5,34,[64][65][66][67][68][69][70][71][72][73] Interobserver agreement was assessed for 5 CTA methods, ranging from moderate to excellent (n ϭ 247). One grading scale used a combination of CTP in addition to CTA to confirm the retrograde direction of true LMF.…”

The role of imaging in acute ischemic stroke

“…CTA has reportedly high sensitivity (97%-100%) and specificity (98%-100%) for detecting intracranial occlusions and stenoses. 66,79,102,111,157,199,214,222 CTA also performs well in characterizing extracranial occlusions and stenoses, with high sensitivity (95%-97%) and specificity (90%-99%). 112 In addition to evaluating the degree of stenosis in the extracranial arteries, CTA provides valuable information of the plaque-such as morphology and composition.…”

Stroke and the emergency medical services – enhancing performance within the chain of survival

“…It can be complemented, however, with an iodised contrast medium to enable the use of CT angiography (CTA) and perfusion CT (PCT). Knauth et al 1997, Shrier et al 1997, Wildermuth et al 1998, Graf et al 2000, Verro et al 2002, Hirai et al 2002. It can also be used to identify the exact location of an intracranial bleeding.…”