Double Inversion Recovery MR in cerebrovascular disease

Cortical microinfarcts (CMIs) are a common finding in patients with cerebrovascular risk factors. Clinico-pathological studies link CMIs with later life cognitive decline. Double Inversion Recovery (DIR) MR is a novel MR sequence that offers a higher sensitivity compared to conventional imaging in intracortical demyelinating lesions detection in Multiple Sclerosis. DIR has never been applied in cerebrovascular disease, but it could potentially feel the gap between histhopathology and patients and fullfill the clinical need of prognostic markers of cognitive decline in vivo. To test whether DIR is feasible to detect ischemic intracortical lesions, we chose to study by DIR (Achieva 1.5 T and 8 channels head Phase-Array coil with parallel imaging capabilities-SENSE, Philips Medical Systems, Best, The Netherlands) and conventional imaging the long term radiological evolution of 23 cortical Diffusion Weighted restricted areas (DWIrls) occurring post-procedure in 5 patients undergoing carotid artery stenting. Fourteen out of 23 lesions were detectable by follow up DIR. DIR more likely unveiled gliotic lesions originating from DWIrls compared to concurrent FLAIR (p = 0,078). Therefore in an independent cohort including 62 patients with common cerebrovascular risk factors stratified in three groups by carotid artery disease severity, we applied DIR to establish the prevalence of intracortical lesions (DIRlns) according to cerebrovascular risks factors and carotid artery stenosis severity. Among cerebrovascular and demographic variables explored (hypertension, hypercholesterolemia, smoking, IMT and antiplatelet therapy) Linear regression analysis showed a significant association only between age and DIRlns (Pearson's = .496, p <0.01). After correcting for age, DIRlns load resulted significantly dependent on carotid artery stenosis severity (F = 5.56, p <0.01). We concluded that DIR is feasible to detect chronic intracortical ischemic lesions in vivo; moreover the main determinant of DIRlns accrual seems to be the carotid artery disease. Microembolism and impaired cerebral heamodynamic may act as physiopathological mechanisms underlying cortical ischemic damage. Further studies are needed to confirm these results in larger group, to investigate the functional consequences of cortical damage in vivo and to establish the role of cerebral vasomotor reactivity efficiency in cortical damage accumulation.