Alberta Stroke Program Early CT Score (ASPECTS) in Ischemic Stroke

The Alberta Stroke Programme Early CT Score (ASPECTS) was proposed in 2000 in order to to standardize the detection and reporting of the extent of hypodensity of middle cerebral artery (MCA) territory in a CT of ischemic stroke. The MCA territory is divided into 10 regions of interest (ROI) on two CT axial slices. These 10 regions is shown as below:

1. caudate

2. insula

3. lenticular nucleus,

4. internal capsule,

5. and six other cortical regions of MCA territory designated M1-M6

ASPECT 2

The image above shows the normal plain CT with APSECTS labeling. I=Insula, L=lentiform, C=caudate nucleus, IC=internal capsule, M1= anterior inferior frontal MCA cortex, M2= temporal lobe MCA cortex lateral to insular ribbon, M3= posterior temporal MCA cortex. Image obtained from [ref1]

20130316-170931.jpg

Image above shows the plain CT of ASPECTS region. M4,M5, and M6 correspond to anterior,lateral and posterior MCA cortices immediately rostal to M1, M2, and M3 respectively. Image obtained from [ref1].

The score is calculated by a total of 10 subtracting by the number of area appears hypodense in CT. Thus, “10” is normal and “0” for a completely infarcted MCA territory.

ASPECT 1

Image above shows the plain CT brain with ASPECTS label. The axial section is at level of basal ganglia on left image and at supraganglionic level on right image. There is hypodensity in caudate nucleus, lentiform nucleus, insular cortex, M1, M2, M4, M5 and M6 regions on left side, resulting ASPECTS of 2. Image obtained from [ref5].

The clinical importance of ASPECTS is its prognostic value for determining clinical outcome after intravenous tissue plasminogen activator (i.v. tPA) in management of acute ischaemic stroke. There is a sharp increase in dependence and death occurs with an ASPECTS of 7 or less; attributed to symptomatic intracerebral hemorrhage. Hence, it is not recommended to use i.v. tPA with ASPECTS score of 7 or less.

Besides that, within the first 3 h of MCA stroke onset, baseline ASPECTS value correlated inversely with the severity of stroke on the National Institutes of Health Stroke Scale (NIHSS).

References:
1. R.G Gonzalez et al. Acute ischemic stroke: imaging and intervention. Second edition. Springer, New York, NY. 2011.
2. Philip A. Barber et al.Validity and reliability of a quantitative computed tomography score in predicting outcome of hyperacute stroke before thrombolytic therapy. The Lancet. 2000;355(9216):1670-1674.
3. J. H. Warwick Pexman et al. Use of the Alberta Stroke Program Early CT Score (ASPECTS) for Assessing CT Scans in Patients with Acute Stroke. AJNR. 2001;22:1534-1542.
4. Geoffrey A. Donnan et al. How to make better use of thrombolytic therapy in acute ischemic stroke. Nature. 2011;7:400-409.
5. Paresh Zanzmera et al. Prediction of stroke outcome in relation to Alberta Stroke Program Early CT Score (ASPECTS) at admission in acute ischemic stroke: A prospective study from tertiary care hospital in north India. Neurology Asia. 2012;17(2):101–107.

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