Cerebral Hypoperfusion Can Be Improved by Carotid Artery Stenting

A 64-year-old man suffering from several episodes of transient ischemic attack with weakness of his left arm and leg was referred to the department of radiology. Pre-interventional work-up included cranial MRI, indicating several lacunar spots in the right-sided subcortical and periventricular white matter without signs of cytotoxic edema as an indicator of acute ischemia (images not shown). MR perfusion imaging uses a dynamic, T2*-weighted echo-planar fast-field echo susceptibility sequence in the axial orientation with intra-venous contrast enhancement. The standardized time-to-peak (stdTTP) measurement provides a quantitative measure of the hemodynamic situation of the brain and has been shown as significantly increased with higher grades of stenotic or occlusive carotid artery disease. 1 Nasel C. Kronsteiner N. Schindler E. Kreuzer S. Gentzsch S. Standardized time to peak in ischemic and regular cerebral tissue measured with perfusion MR imaging. AJNR Am J Neuroradiol. 2004; 25: 945-950 PubMed Google Scholar , 2 Nasel C. Azizi A. Wilfort A. Mallek R. Schindler E. Measurement of time-to-peak parameter by use of a new standardization method in patients with stenotic or occlusive disease of the carotid artery. AJNR Am J Neuroradiol. 2001; 22: 1056-1061 PubMed Google Scholar A stdTTP ≤3.5 seconds is reported to be regular, and evidence suggests that an stdTTP ≥7 seconds indicates critically perfused tissue. 1 Nasel C. Kronsteiner N. Schindler E. Kreuzer S. Gentzsch S. Standardized time to peak in ischemic and regular cerebral tissue measured with perfusion MR imaging. AJNR Am J Neuroradiol. 2004; 25: 945-950 PubMed Google Scholar , 2 Nasel C. Azizi A. Wilfort A. Mallek R. Schindler E. Measurement of time-to-peak parameter by use of a new standardization method in patients with stenotic or occlusive disease of the carotid artery. AJNR Am J Neuroradiol. 2001; 22: 1056-1061 PubMed Google Scholar In this patient, MR perfusion imaging showed a severe hypoperfusion in the corresponding vascular territory of the right middle cerebral artery (Figure 1b). Pre-interventional color Doppler ultrasound (images not shown) and intra-arterial digital subtraction angiography (Figure 1a) revealed a right-sided high-grade internal carotid artery stenosis, which was successfully treated by protected carotid artery stenting with a good angiographic outcome (Figure 2a). Post-interventional MRI, performed 2 days after stent placement, showed no signs of cytotoxic edema as an indicator of relevant peri-interventional cerebral embolism and a restoration of regular, symmetric perfusion (see Figure 2b). These images suggest that carotid artery stenting can not only protect cerebral embolism from plaque material of internal carotid artery stenosis, but can also improve pre-existent cerebral hypoperfusion. Figure 2Intra-arterial digital subtraction angiography (a) after successful stent implantation in the same patient with a good angiographic outcome and corresponding magnetic resonance perfusion map (obtained 2 days post-interventionally) of the brain (b) indicating restored regular, symmetric perfusion of both hemispheres. View Large Image Figure Viewer