CT angiography source image ASPECTS

Last revised by Frank Gaillard on 7 Feb 2024

CT angiography source image ASPECTS (CTA-SI ASPECTS) is an adaptation of ASPECTS for CTA and is a semiquantitative scoring system to characterize the extent and severity of mainly middle cerebral artery ischemic stroke, although it can be adapted to other vascular territories as well.

The added value of CTA-SI ASPECTS, over the usual ASPECTS generated from non-contrast CT, is that it directly shows the degree of collateral circulation and better delineates the infarct territory during the acute phase 1. Furthermore, differences in contrast enhancement are typically less subtle than the often discrete hypoattenuation caused by early-phase ischemia on noncontrast scans. 


CTA-SI ASPECTS is evaluated using axially reconstructed brain window scans generated from the CTA source images 2

For the MCA territory a 10-point scoring system is used identically to the original ASPECTS system for non-contrast CT, where any region of relatively diminished contrast enhancement should be registered as abnormal 1

Clinical use

It has been demonstrated that a good CTA-SI ASPECTS score (8-10) is a superior predictor of the final infarct size and clinical outcome to the standard ASPECTS, and most importantly it was found to be a better indicator of the possible outcome of endovascular treatment 1,2

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Cases and figures

  • Case 1: CTA-SI score: 0
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  • Case 1: noncontrast CT of the same patient. ASPECTS: 7
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