QUANTITATIVE PROCESSING OF T2-WEIGHTED CEREBRAL MRI CONCOMITANT WITH THIN-SLICE CORTEX MEASUREMENTS IN PATIENTS WITH SEVERE CAROTID ATHEROSCLEROSIS FOR PROGNOSIS OF CEREBRAL COMPLICATIONS AFTER INVASIVE CARDIOVASCULAR INTERVENTIONS
Authors: Ussov W. Yu. , Yaroshevsky S. P. , Tlyuniaeva A. M. , Maksimova A. S. , Alekseeva L. N. , Suhareva A. E. 
Published: January 2019

Fim of the study. We attempted to select a complex of signs for prognosis of early post-intervention stroke in patients referred for extensive invasive cardiovascular surgery or intravascular procedures, from the data of routine MRI of the brain.

Material and methods. Basing on the histories of 540 patients underwent non-carotid cadiosurgical or invasive intravascular procedures we selected ten in whom the post-operation early stroke was diagnosed and who also underwent pre-surgically the MRI study of the brain. The control comparative group comprised twelve persons in whom no post-intervention stroke was observed and also pre-intervention MRI was present. At the admission before surgery or intervention in everybody the T2-weighted MRI has been carried out in T2-weighted and T1-weighted thin slice (1,5– 3 mm) modes with subsequent quantification of cerebral ischemic preconditioning from quantitatification of T2-w. Imaged and with measurement of cortex’thickness.

Results. In patients of both post-surgical stroke and control groups the coexistance of critical carotid stenosis or carotid occlusion with contralateral subcritical or mild/minimal contralateral carotid stenosis was detected. The post-operation ishemic stroke was detected in those persons obly, in whom pre-surgically the region of ishaemic leucodystrophy (unilateral leucoarayosis) was detected as signal-enhanced region on T2-weighted MRI scans on the side of carotid occlusion/critical stenosis, simultaneously with cortical thinning on the side. The index of physical volume of the T2-w.hyperintence region was in patients in whom post-surgically the ischemic stroke occurred as high as 18–51 сm3, whereas the volume of irreversibly damaged tissue diffusely distributed over the T2-w.hyperintensive leucoarayosis area 3,9–14,7 сm3. The ratio of volumes of irreversibly damaged tissue to the physical volume of damage was 0,17–0,29. Simultaneously in these persons in the middle cerebral artery perfusion region ipsilaterally the relative thinning of the cortex was seen with no cerebral stroke in the personal history. The cortex was in these patients on the side of ICA critical stenosis/ ICA occlusion 1,7–3,1 mm, and contralaterally 2,5–3,2 mm, with asimmetry index 0,65–0,82. This syndrome of «ischemic preconditioning of the brain» seen as combination {T2-hyperintensity & cortical dystrophy} was also detected in hree patients in whom the ishaemic stroke after cardiovascular surgery did not occur, and all these persons were treated befor the operation with high — up to 750 mg daily — doses ethylmethyl hydroxypiridine succinate (mexidol). The sensitivity of MRI syndrome {T2-hyperintensity & cortical dystrophy} in prognosis of post-operation ischemic stroke was as high as 100%, whereas specificity 75%, and diagnostic accuracy 86%.

Conclusion. Thus, the detection of extensive unilateral area of T2-hyperintensity in the internal carotid artery region (unilateral leucoarayosis) concomitant with thinning of cortex in the region, on the side of occlusion or critical stenosis of internal carotid artery can be accepted as factor of high risk of ishemic stroke early after extensive vascular surgery or intervention. It is necessary to carry out the MRI study of the brain in every patient before and after extensive cardiovascular intervention, for scoring of stroke risk early after procedure.