Imaging Biomarkers for Intra-arterial Stroke Therapy

Abstract

Despite high rates of early revascularization with intra-arterial stroke therapy, the clinical efficacy of this approach has not been clearly demonstrated. Neuroimaging biomarkers will be useful in future trials for patient selection and for outcomes evaluation. To identify patients who are likely to benefit from intra-arterial therapy, the combination of vessel imaging, infarct size quantification and degree of neurologic deficit appears critical. Perfusion imaging may be useful in specific circumstances, but requires further validation. For measuring treatment outcomes, surrogate biomarkers that appear suitable are angiographic reperfusion as measured by the modified Thrombolysis in Cerebral Infarction scale and final infarct volume.

Keywords: Acute ischemic stroke; CT; Endo-vascular; Intra-arterial; MRI; Neuroimaging; Reperfusion therapy.

FIGURE 1

27-Year-old male with NIHSS score of 25 secondary to right middle cerebral artery (MCA) M1 segment occlusion (arrow) as shown on coronal CT angiography (CTA) maximum intensity projection (MIP) image (a). Diffusion weighted (DWI; b) and apparent diffusion coefficient (ADC; c) images, performed 1 h, 48 min after stroke onset, revealed a large infarct volume of 93.1 ml. 88-Year-old female with NIHSS score of 22 secondary to left MCA M1 segment occlusion (arrow) as shown on coronal CTA MIP (d). She received intravenous tissue plasminogen activator 2 h after stroke onset at outside hospital, and was transferred to our center where DWI (e) and ADC (f) images, performed 5 h, 20 min after stroke onset, revealed a small infarct volume of 12 ml.

FIGURE 2

82-Year-old female with NIHSS score of 10 presents 3 h after stroke onset. Thin-section noncontrast CT MIP data (a) demonstrate a long hyperdense clot (arrows) within the right internal carotid and middle cerebral arteries. The occlusion (arrows) is confirmed on the coronal CTA MIP (b). The hyperdense clot measured 30.7 mm.