Biomedical subjects

Dominique Hervé

Publications and source records attributed to Dominique Hervé.

3 recordsLinked to original sources

PubMed2005

Shape and volume of lacunar infarcts: a 3D MRI study in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy.

BACKGROUND AND PURPOSE: The shape and exact size of lacunar infarcts have been investigated only postmortem. Recent imaging techniques based on triangulation and connectivity can now be used for 3D segmentation of cerebral lesions. The shape and size of lacunar infarcts was investigated using these techniques in 10 cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) patients. METHODS: We segmented 102 lacunar infarcts on T1-weighted images. The surface of the corresponding set of voxels was computed as a mesh of triangles. Thereafter, the shape of each lesion in 3D was visually analyzed by 2 investigators. RESULTS: The volume of lesions ranged from 10.5 to 1146 mm, with 93% of them having a volume <500 mm; 83% lacunar infarcts had a spheroid or ovoid shape, but 17% presented as sticks, slabs, or with a complex shape. Lesions with multiple components appeared larger than the others, and a tail extension was noticed in 13 of 102 lesions. CONCLUSIONS: These results suggest the following: (1) most lacunar infarcts in CADASIL have a volume far below one third of that of a sphere of 15 mm in diameter, the upper limit currently used for their identification on 2D imaging; (2) a significant proportion of lacunar infarcts have a shape distinct from the spheroid-ovoid morphology; and (3) lesions with a complex shape may result from the involvement of the largest small arteries, confluence of ischemic lesions, or secondary tissue degeneration. The segmentation of lacunar infarcts appears promising to better understand the pathophysiology of tissue lesions secondary to small vessel diseases.

Aged↗

PubMed2005

Longitudinal diffusion changes in cerebral hemispheres after MCA infarcts.

Diffusion tensor imaging can be used in vivo to assess the longitudinal and regional microstructural changes occurring after middle cerebral artery (MCA) infarcts in humans. Nine patients were investigated 1 week (D7), 1 (M1), 3 (M3), and 6 months (M6) after the occurrence of an isolated MCA infarction. First, an overall analysis was performed using histograms of mean diffusivity (MD) and fractional anisotropy (FA) in each hemisphere. Thereafter, the regional pattern of diffusion changes was investigated voxel by voxel with statistical parametric mapping 99. In the hemisphere ipsilateral to the infarction, histogram analysis revealed a significant decrease in FA between D7 and M6 associated with a progressive increase in MD from D7 to M3. Remote from the MCA territory, the voxel by voxel analyses detected a significant increase in MD within the thalamus at M3 and M6 and a reduction in FA along the pyramidal tract at M6. In the contralateral hemisphere, between D7 and M6, a significant hemispheric atrophy was observed in association with a global reduction in anisotropy, in the absence of distinctive regional diffusion changes. These results suggest that micro- and macrostructural tissue modifications can be detected with diffusion tensor imaging in regions remote from the ischemic area in both hemispheres.

Adult↗

PubMed2004

Predictive values of lacunar transient ischemic attacks.

BACKGROUND AND PURPOSE: We postulated that a lacunar syndrome occurring with transient ischemic attacks (TIAs) or progressive nonsudden onset predicts a brain infarction (BI), presumably caused by a small artery disease (ie, lacunar BI) better than a lacunar syndrome with sudden onset. METHODS: We included 510 patients with BI. BI was classified into etiologic groups including lacunar BI group. We identified the patients with lacunar or nonlacunar syndrome, and those with TIAs preceding the BI or with symptoms of nonsudden onset. RESULTS: Nonlacunar syndrome had a negative predictive value for a lacunar BI of 95%. A lacunar syndrome had a positive predictive value (PPV) of 57% for lacunar infarction (n=109), and the PPV increased to 79% in the case of recent TIAs preceding the lacunar syndrome. Hypertension was present in 95% of cases with lacunar TIAs (odds ratio: 10.69; 95% confidence interval: 1.34 to 84.82; P=0.02). CONCLUSIONS: Lacunar TIAs are almost always associated with history of arterial hypertension and have a high PPV for lacunar BI. This subgroup of patients may reflect different underlying mechanisms than the group of patient with lacunar syndrome of sudden onset.

Adolescent↗