Volker Puetz MD, Abstract Co-Author: Nothing to Disclose

Mayank Goyal, Presenter: Nothing to Disclose

Imanuel Dzialowski, Abstract Co-Author: Nothing to Disclose

Andrew M. Demchuk MD, Abstract Co-Author: Nothing to Disclose

The impact of intracranial nonocclusive thrombus (iNOT) in acute ischemic stroke is unknown. We sought to determine the clinical course of patients with iNOT diagnosed by CT angiography (CTA).

Six hundred sixty-five patients underwent CTA for acute ischemic stroke from 06/02 to 03/06. We identified iNOT from CTA reports and analysed the clinical data of these patients. General criteria to diagnose iNOT rather than intracranial atherosclerotic stenosis were 1) regular shape of the thrombus 2) eccentricity of the residual lumen 3) clot location in the distal M1 or M2 segments or top of the basilar artery 4) absence of vessel wall calcification 5) presence of multiplicity. If atherosclerotic stenosis or occlusive thrombus were felt likely these patients were excluded from analysis. Repeated vascular studies consisted of repeated CTA, MR angiography, digital subtraction angiography or transcranial Doppler sonsography (TCD) if acute TCD was available. Functional indepence at discharge was defined as a modified Rankin scale (mRS) score < 2.

Twenty-five patients (3.8%) had iNOT on CTA. Median age 65.5 years (38-85), NIHSS score 3 (0-23), onset to CTA time 3 hours (0.5-69). Six patients suffered stroke progression or recurrent stroke after a median time of 20.5 hours (0-72) from onset. One of them was successfully treated with intraarterial Alteplase and improved to functional independence. The other 5 patients remained dependent. We performed repeated vascular studies in 21/25 patients. In patients with unchanged or enlarged iNOT, 4/9 (44%) suffered stroke progression or recurrent stroke. 1/12 (8%) patients with diminished or resolved iNOT suffered a recurrent stroke which involved a different vascular territory. All patients without stroke progression or recurrent stroke were independent at discharge.

Presence of iNOT represents a group of patients at risk for stroke progression or recurrence. Although a majority has a good functional outcome the subgroup with persistent or progressing iNOT appears to be at risk.

Therapeutic options may need to be considered in patients with intracranial non-occlusive thrombus.

Puetz, V, Goyal, M, Dzialowski, I, Demchuk, A, Intracranial Nonocclusive Thrombus on CT Angiography: Reason to Be Concerned?.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5007039.html