The Role of White Matter Damage in the Risk of Periprocedural Diffusion-Weighted Lesions after Carotid Artery Stenting.

BACKGROUND: White matter hyperintensities (WMH) are a common finding in aged individuals affected by carotid artery disease and are a risk factor for first-ever and recurrent stroke. We investigated if white matter damage increases the risk of brain microembolism during carotid artery stenting (CAS), as evaluated by the appearance of new areas of restricted diffusion on diffusion-weighted images (DWI). METHODS: We evaluated 47 patients with severe internal carotid artery (ICA) stenosis undergoing CAS, comparing preprocedural clinical, ultrasound and radiological characteristics. WMH volume was computed on FLAIR images before CAS. After CAS, the DWI scan was looked over for areas of restricted diffusion (DWI lesions). A first univariate analysis was adopted to compare groups according to the occurrence of DWI lesions. Then, the variable DWI lesion was modelled by means of a logistic regression model. RESULTS: Seventeen patients developed at least 1 DWI lesion after CAS. Compared with non-DWI, DWI patients were more commonly treated in the left ICA (p = 0.007) and had a more severe WMH damage (p = 0.027). Indeed, the risk of a DWI lesion was higher in left versus right stenosis (OR = 9.0, 95% CI 1.9-42.7, p = 0.005) and increased for each log-unit of WMH lesion load (OR = 7.05, 95% CI 1.07-46.49, p = 0.042). A WMH lesion load of at least 5.25 cm3 had a 50% probability of occurrence of a new DWI lesion. CONCLUSIONS: Treated side and preexisting white matter damage are risk conditions for brain microembolism during CAS. This should be taken into account to optimize severe carotid artery disease management.

Diffusion-weighted lesions after carotid artery stenting are associated with cognitive impairment.

The effect of carotid artery stenting (CAS) on cognitive function is still debated. Cerebral microembolism, detectable by post-procedural diffusion-weighted imaging (DWI) lesions, has been suggested to predispose to cognitive decline. Our study aimed at evaluating the effect of CAS on cognitive profile focusing on the potential role of cerebral microembolic lesions, taking into consideration the impact of factors potentially influencing cognitive status (demographic features, vascular risk profile, neuropsychological evaluation at baseline and magnetic resonance (MR) markers of brain structural damage). Thirty-seven patients with severe carotid artery stenosis were enrolled. Neurological assessment, neuropsychological evaluation and brain MR were performed the day before CAS (E0). Brain MR with DWI was repeated the day after CAS (E1), while neuropsychological evaluation was done after a 14-month median period (E2). Volumes of both white matter hyperintensities and whole brain were estimated at E0 on axial MR FLAIR and T1w-SE sequences, respectively. Unadjusted ANOVA analysis showed a significant CAS*DWI interaction for MMSE (F=7.154(32), p=.012). After adjusting for factors potentially influencing cognitive status CAS*DWI interaction was confirmed for MMSE (F=7.092(13), p=.020). Patients with DWI lesions showed a mean E2-E0 MMSE reduction of -3.1, while group without DWI lesions showed a mean E2-E0 MMSE of +1.1. Our study showed that peri-procedural brain microembolic load impacts negatively on cognitive functions, independently from the influence of patients-related variables.

Enhancement patterns of prostate cancer in dynamic MRI.

Our objective was to analyze fast-field-echo dynamic subtracted (FFE/DS) MRI data in prostate cancer, in order to recognize enhancement patterns of tumoral tissue in comparison with non-tumoral peripheral prostatic tissue. Eleven consecutive patients with prostate cancer were proposed for radical prostatectomy. Before surgery, all patients underwent endorectal coil MRI examination. In addition to standard sequences, a dynamic study was performed by FFE/DS to evaluate tumoral behavior after Gd-DTPA rapid infusion. Analysis of the imaging was made by the means of the time/signal intensity curve obtained during early contrast medium enhancement, sampling both the abnormal enhancing focal area and the opposite lobe at the level of the main prostatic tissue. A focal area of increased enhancement was observed in the site of the tumor in all cases. The time/intensity curve sampled on this area and compared with the opposite lobe demonstrated a high confidence interval of the difference of the data: mean tumor maximal intensity 1331 (SD 187) vs normal 470 (SD 139) and mean tumor rise time 103 s (SD 30) vs normal 250 (SD 38; p<0.01). In tumoral tissue, the enhancement percentage of signal intensity (SI%=pre-contrast minus post-contrast/pre-contrast x100) was 316.7%. At FFE/DS, there is a typical behavior of the time/intensity curve of contrast enhancement in prostatic cancer that might be employed in diagnosis of the disease.