Implication of Ventricular Asymmetry Analyzed by Neuropsychological Test and Tc-99m ECD SPECT in Patients with Frontotemporal Dementia

BACKGROUND: Frontotemporal dementia (FTD) has a characteristic pattern of lobar atrophy in frontal and/or temporal lobes. Asymmetry in the lateral ventricle size on brain magnetic resonance image (MRI) in FTD patients may have clinical significance. This study compares the ventricular asymmetry seen on MRI with that of the neuropsychological difference and asymmetric hypoperfusion using statistical parametric mapping (SPM) analysis of brain SPECT in patients with FTD. METHODS: Thirteen FTD patients who underwent Brain MRI, TC-99m ECD SPECT and neuropsychological testing and who had the ventricular asymmetry on brain MRI were retrospectively selected. The patients were divided into two groups (5 right dominant group, 8 left dominant group) according to the ventricular asymmetry on brain MRI. We compared the regional blood flow pattern on TC-99m ECD SPECT images using SPM analysis and the results of neuropsychological tests between the two groups. RESULTS: In the right dominant group, a significant perfusion deficit was identified at the bilateral frontal regions. In the left dominant group, significant hypoperfusion was found at the left frontotemporal regions (uncorrected p<0.001). There was no significant difference of neuropsychological testing in between the two groups. However, the score on the Neuropsychiatric Inventory (NPI) in the right dominant group was higher than that of the left dominant group (p=0.043). CONCLUSIONS: Hemispheric asymmetry on brain MRI was common in patients with FTD and was related with a characteristic pattern of hypoperfusion on brain SPECT images and neuropsychiatric symptoms.

Flow Diversion on TCD in Symptomatic MCA Steno-Occlusive Disorder: Evidence of Leptomeningeal Collateral Circulation

BACKGROUND: To investigate the clinical significance of flow diversion (FD) of the anterior cerebral artery (ACA) or posterior cerebral artery (PCA), a transcranial doppler (TCD) was used in patients with middle cerebral artery (MCA) occlusive disorders. METHODS: This is a retrospective study of 51 patients from 1999 to 2001. FD was determined using TCD. Leptomeningeal collateral channels (LMCs) were identified by conventional angiography. The author analyzed the sensitivity, specificity, positive and negative predictability of FD of ACA or PCA to predict the LMCs, and also evaluated the relationship between FD and leptomeningeal collateral circulation. RESULTS: LMC was noted in 41% of patients with M1 (MCA) occlusive disorders. It showed a tendency of increasing prevalence with an increasing degree of M1 MCA stenosis (rho=0.605, p<0.001). FD was noted in 47% of patients with MCA occlusive diseases. It also had a tendency of high prevalence with an increasing degree of M1 MCA stenosis (rho=0.382, p=0.006). To predict the presence of LMCs, FD of ACA or PCA had a sensitivity of 81%, specificity of 76%, positive predictive value of 71% and negative predictive value of 85%. FD of ACA or PCA had a good correlation with LMCs in patients with MCA occlusive disorders (rho=0.568, p<0.001). CONCLUSIONS: These results suggest that FD had good sensitivity and specificity to predict the LMCs, and demonstrated that FD was a reliable source of evidence of LMCs in patients with M1 MCA occlusive disorders. Patients with M1 MCA stenosis had heterogeneous hemodynamics in the development of collateral circulation.

The Usefulness of Diffusion Tensor MRI for the Prediction of Clinical Outcome in Patients with Acute Subcortical Infarction

BACKGROUND: Diffusion tensor MRI (DTI) is a new imaging technique and enables us to analyze the structural damage of fiber pathways and to monitor the time course of Wallerian degeneration of the pyramidal tract in stroke patients. We used DTI to investigate structural changes of the infarct area and the associated descending corticospinal tract in patients with subcortical infarct. METHODS: We examined 24 consecutive patients who presented with acute single cerebral infarct in the subcortical area and who also had undergone an MRI study within 7 days after symptom onset. Clinical outcome was assessed using the National Institutes of Health Stroke Scale (NIHSS) at admission, 7 days, 14 days and 30 days and modified Rankin Scale (mRS) at admission and 30 days. Each of the indices was achieved by post processing the acquired DTI data and correlated with the NIHSS. RESULTS: In infarct region, fractional anisotropy (FA) was significantly decreased compared with matched-contralateral regions (0.39 vs. 0.53, p<0.001). In the distal to the infarct, FA was significantly decreased at internal capsule (0.62 vs. 0.64, p=0.019), not at pons (0.51 vs. 0.53, p=0.103). The decrease of anisotropy at infarct region correlated positively with the NIHSS at 7, 14 and 30 days and mRS at 30 days after stroke, but the decrease of anisotropy at internal capsule did not correlate with the NIHSS. CONCLUSIONS: This study shows the potential of DTI to detect and monitor the structural degeneration of fiber pathways and to establish the prognosis in patients with acute subcortical cerebral infarct.

Ipsilateral Hemiparesis Caused by a Internal Capsule Infarct after a Previous Stroke on the Opposite Side

A 63-year-old man was admitted with newly developed left hemiparesis. He had experienced left hemiparesis that had resulted from an earlier right thalamic hemorrhage. Diffusion-weighted images showed only high signal intensity lesion in the left internal capsule. Ipsilateral motor evoked potentials were obtained at the affected hand muscles when the unaffected motor cortex was stimulated. This suggests that cortical reorganization in the unaffected hemisphere after the first stroke may be involved in the occurrence of such symptom.

Prolonged Hyperkinesia Contralateral to Hemiparesis in Patients with Basal Ganglia Infarction

Abnormal motor behaviors caused by ipsilateral hemispheric lesions have not been frequently reported. However, a 76-year-old woman developed left hemiparesis and abnormal movements of the right limb. Upon observation, she would unintentionally rotate her hand continuously on the table in a stereotypical way. A brain CT showed an infarction in the basal ganglia and corona radiata. We report this patient with unilateral hyperkinesia and contralateral hemiparesis due to ipsilateral basal ganglia lesions.

Assessment of Collateral Circulation through Anterior Cerebral Artery Using the Transcranial Doppler in Patients with Acute Middle Cerebral Artery Infarction

BACKGROUND: To investigate the optimal values of transcranial doppler (TCD) index in the evaluation of leptomeningeal collateral circulation (CC) in patients with middle cerebral artery (MCA) stenosis. METHODS: Forty-one patients, with angiographically confirmed single stenosis or occlusion of the M1 segment of the MCA, were studied with TCD and brain MRI. Patients were divided into two groups according to the existence of CC though ipsilateral anterior cerebral artery on transfemoral cerebral angiography (TFCA). Mean flow velocities (mFV) of anterior and middle cerebral arteries (ACA, MCA) were analyzed. We then investigated the optimal values of TCD flow index: 1) ipsilateral mFV ACA/MCA (AMVR), 2) ACA velocity ratio (ACAVR), 3) mFVACA. We then correlated TCD flow index with TFCA results. RESULTS: TFCA revealed single moderate to severe M1 stenosis (n=35) and occlusion (n=6). Presence of CC was found in 11 (27%), absence of CC in 30 (73%). The mean of AMVR, ACAVR and mFVACA differed between the two groups: 1.76 +/- 0.69, 1.43 +/- 36, 86.27 +/- 31.73 cm/s in the presence of CC; 0.48 +/- 0.24, 1.21 +/- 0.39, 65.93 +/- 23.24 in the absence of CC. The optimal cutoff values for detection of CC were found at AMVR>or=0.9, ACAVR>or=1.30 and mFVACA>or=80 cm/s. The combination of individual TCD indexes had improved the specificity and positive predicted value in the detection of CC. CONCLUSIONS: TCD enables detecting the existence of CC in patients with MCA stenoocclusion. These optimal values may provide a noninvasive method for evaluate the pathomechanism of stroke and prospect the prognosis of these patients.