MRI Parameters Of Alzheimer's Disease in an Arab Population of Wadi Ara, Israel

Magnetic resonance imaging (MRI) findings are reported from 15 individuals in an Arab–Israeli community who were diagnosed with Alzheimer's disease (AD). The quantitative parameters that were used for MRI analyses included gradings (0–3) and linear measurements of different brain structures. Generalized tissue loss was assessed by combined measurements of the ventricles (ventricular score, VS) and sulcal grading and width (SG, SW, respectively). Loss of brain tissue in specific regions of interest, eg, temporal lobes, basal ganglia, and midbrain, was evaluated by precise measurements. We observed abnormal tissue characteristics, expressed as high intensity foci in white matter on T2W sequences, as well as tissue loss, both generalized and focal. Most notable were changes involving the head of the caudate nuclei, the midbrain, and to a lesser degree, medial temporal structures.National Institute of Aging (UO1-AG17173); National Institute on Alcohol Abuse and Alcoholism (R37-AA07112, K05-AA00219); US Department of Veterans Affair

Cognitive state following stroke: the predominant role of preexisting white matter lesions.

Stroke is a major cause of cognitive impairment and dementia in adults, however the role of the ischemic lesions themselves, on top of other risk factors known in the elderly, remains controversial. This study used structural equation modeling to determine the respective impact of the new ischemic lesions' volume, preexisting white matter lesions and white matter integrity on post stroke cognitive state.Consecutive first ever mild to moderate stroke or transient ischemic attack patients recruited into the ongoing prospective TABASCO study underwent magnetic resonance imaging scans within seven days of stroke onset and were cognitively assessed one year after the event using a computerized neuropsychological battery. The volumes of both ischemic lesions and preexisting white matter lesions and the integrity of the normal appearing white matter tissue were measured and their contribution to cognitive state was assessed using structural equation modeling path analysis taking into account demographic parameters. Two models were hypothesized, differing by the role of ischemic lesions' volume.Structural equation modeling analysis of 142 patients confirmed the predominant role of white matter lesion volume (standardized path coefficient β =  -0.231) and normal appearing white matter integrity (β =  -0.176) on the global cognitive score, while ischemic lesions' volume showed no such effect (β = 0.038). The model excluding the ischemic lesion presented better fit to the data (comparative fit index 0.9 versus 0.092).Mild to moderate stroke patients with preexisting white matter lesions are more vulnerable to cognitive impairment regardless of their new ischemic lesions. Thus, these patients can serve as a target group for studies on cognitive rehabilitation and neuro-protective therapies which may, in turn, slow their cognitive deterioration

Hemodynamic response imaging: a potential tool for the assessment of angiogenesis in brain tumors.

Blood oxygenation level dependence (BOLD) imaging under either hypercapnia or hyperoxia has been used to study neuronal activation and for assessment of various brain pathologies. We evaluated the benefit of a combined protocol of BOLD imaging during both hyperoxic and hypercapnic challenges (termed hemodynamic response imaging (HRI)). Nineteen healthy controls and seven patients with primary brain tumors were included: six with glioblastoma (two newly diagnosed and four with recurrent tumors) and one with atypical-meningioma. Maps of percent signal intensity changes (ΔS) during hyperoxia (carbogen; 95%O2+5%CO2) and hypercapnia (95%air+5%CO2) challenges and vascular reactivity mismatch maps (VRM; voxels that responded to carbogen with reduced/absent response to CO2) were calculated. VRM values were measured in white matter (WM) and gray matter (GM) areas of healthy subjects and used as threshold values in patients. Significantly higher response to carbogen was detected in healthy subjects, compared to hypercapnia, with a GM/WM ratio of 3.8 during both challenges. In patients with newly diagnosed/treatment-naive tumors (n = 3), increased response to carbogen was detected with substantially increased VRM response (compared to threshold values) within and around the tumors. In patients with recurrent tumors, reduced/absent response during both challenges was demonstrated. An additional finding in 2 of 4 patients with recurrent glioblastoma was a negative response during carbogen, distant from tumor location, which may indicate steal effect. In conclusion, the HRI method enables the assessment of blood vessel functionality and reactivity. Reference values from healthy subjects are presented and preliminary results demonstrate the potential of this method to complement perfusion imaging for the detection and follow up of angiogenesis in patients with brain tumors

Structural equation models for the prediction of cognitive state after one year.

<p>Subtext: The numbers on the arcs represent the contribution of each parameter to its neighbor. * <i>p</i><0.05 **<i>p</i><0.001. Abbreviations: ILV, ischemic lesions' volume; WML, white matter lesions; NAWM, normal appearing white matter.</p

Tissue segmentation example.

<p>Subtext: A 60 year old male, scanned two days following stroke onset (A) FLAIR, fluid-attenuated inversion recovery image; (B) Ischemic lesion (blue); (C) WML, white matter lesions (yellow); (D) NAWM, normal appearing white matter (copper).</p

Associations between white matter lesion volume and white matter tissue integrity parameters.

<p>Associations between white matter lesion volume and white matter tissue integrity parameters.</p

Summary of unadjusted and adjusted regressions for predicting global cognitive score one year after stroke.

<p>Summary of unadjusted and adjusted regressions for predicting global cognitive score one year after stroke.</p

Study population demographic and clinical measures, cognitive scores and brain MRI characteristics (data shown as mean ± SD or as number of cases and percentage n (%)).

<p>Study population demographic and clinical measures, cognitive scores and brain MRI characteristics (data shown as mean ± SD or as number of cases and percentage n (%)).</p