Analysis of cerebral blood flow of subcortical vascular dementia with single photon emission computed tomography: adaptation of statistical parametric mapping.

BACKGROUND AND OBJECTIVES: Subcortical vascular dementia (VaD) is a relatively homogeneous subtype of VaD, but the mechanisms of cognitive dysfunction of subcortical VaD are not fully understood. This study investigates the changes of cerebral blood flow (CBF) in patients with subcortical VaD and the contribution of the white matter hyperintensity (WMHI) and clinical severity to CBF changes. METHODS: 99mTc-ethyl cysteinate dimer single photon emission computed tomography (SPECT) was performed to measure the regional CBF and statistical parametric mapping SPM99 software was applied to automated and objective analysis of the SPECT image data. Twenty-three patients (12 male, 11 female) with mild to moderate dementia who met both the criteria of the DSM-IV and probable and possible NINDS-AIREN for VaD and had subcortical white matter changes and lacunar infarctions in brain MRI were evaluated against 17 normal control subjects (7 male, 10 female). The severity of the WMHI was measured by the semi-quantitative scale method proposed by Mäntyla. The Clinical Dementia Rating scale measured the severity of dementia. RESULTS: SPM analysis of the SPECT image reveals significantly reduced regional CBF in the right thalamus, left caudate nucleus, cingulate, bilateral superior temporal, and left ventral subcallosal gyri in subcortical VaD patients compared to the normal controls (corrected P<0.001). Of four WMHIs, only the deep WMHI was associated with the small CBF reduction in the left superior temporal gyrus (uncorrected P<0.01). The reduction of the CBF according to the severity of dementia was noted in the anterior and posterior association areas (uncorrected P<0.01). CONCLUSIONS: Our study suggests that cognitive dysfunction of subcortical VaD may be related to the reduction of the CBF in the brain areas mentioned, which are probably not associated with the severity of periventricular WMHI and dementia.

New subtraction algorithms for evaluation of lesions on dynamic contrast-enhanced MR mammography.

We report new subtraction algorithms for the detection of lesions in dynamic contrast-enhanced MR mammography(CE MRM). Twenty-five patients with suspicious breast lesions underwent dynamic CE MRM using 3D fast low-angle shot. After the acquisition of the T1-weighted scout images, dynamic images were acquired six times after the bolus injection of contrast media. Serial subtractions, step-by-step subtractions, and reverse subtractions, were performed. Two radiologists attempted to differentiate benign from malignant lesion in consensus. The sensitivity, specificity, and accuracy of the method leading to the differentiation of malignant tumor from benign lesions were 85.7, 100, and 96%, respectively. Subtraction images allowed for better visualization of the enhancement as well as its temporal pattern than visual inspection of dynamic images alone. Our findings suggest that the new subtraction algorithm is adequate for screening malignant breast lesions and can potentially replace the time-intensity profile analysis on user-selected regions of interest.