Pigmented neurons in the substantia nigra pars compacta (SNc) and locus coeruleus (LC) show decreased numbers differentially in Parkinson's disease (PD) and multiple system atrophy (MSA). Recent reports have described that fast spin-echo T1-weighted magnetic resonance imaging (MRI) by a 3-tesla machine can visualize neuromelanin-related contrast of the noradrenergic and dopaminergic neurons respectively in the LC and the SNc. Using neuromelanin MRI at 3 T, we investigated possible alterations of these catecholaminergic neurons in 32 PD and 9 MSA patients, and compared the results with those of 23 normal volunteers. The contrast ratio of the LC and SNc was decreased in MSA and PD patients, most prominently in the LC in MSA patients. The contrast ratio of the SNc was correlated with the Hoehn-Yahr stage of PD and the severity of neuroradiological abnormalities in MSA. These results indicate a potential diagnostic value of neuromelanin MRI to distinguish MSA patients from normal and PD patients.

No abstract

No abstract

No abstract

It is considered controversial whether superficial temporal artery (STA)-middle cerebral artery (MCA) bypass affects the outcome of patients with ischemic stroke. This prospective study was undertaken to demonstrate the effect of STA-MCA bypass on the cerebral blood flow and neurological status of the patients with ischemic stroke. Seventy-five patients underwent unilateral or bilateral STA-MCA bypass surgery. The selection of the patients closely adhered to the criteria of the Japan EC-IC Bypass Trial (JET). Cerebral blood flow (CBF) before and after Diamox administration was measured by single photon emission computed tomography (SPECT) using iodine-123-N-isopropyl-p-iodoamphetamine (IMP). MRI, contrast-enhanced 3D CT scans, and angiography were performed on each patient pre- and postoperatively. Bypass surgery was successfully done in all patients. CBF was significantly increased after STA-MCA bypass (P < 0.05). In addition, reservation of CBF was significantly improved after STA-MCA bypass (P < 0.05). Patients with transient ischemic attack (TIA) did not experience recurrence of such episodes after STA-MCA bypass. The neurological deficit was unchanged in patients with complete stroke after bypass surgery. However, the NIH stroke scale was significantly improved after bypass surgery (P < 0.01). In addition, the satisfaction rate of treatment as assessed by the patients themselves was very high after STA-MCA bypass (>90%) compared to the conservative treatment group (<50%). STA-MCA bypass still plays a limited role in the treatment of ischemic stroke, but may become a bright hope in depressed patients after cerebral ischemia.

3D FLAIR imaging permits detection of small high-signal-intensity abnormalities within the drainage territory of DVAs. The size of high-signal-intensity abnormalities increased with patient age.

Catheter ablation is an important non-pharmacological intervention for atrial fibrillation (AF), but its effect on the incidence of asymptomatic cerebral emboli and long-term effects on cognitive function remain unknown. We prospectively enrolled 101 patients who underwent AF ablation. Brain magnetic resonance imaging (MRI) (72 patients) and neuropsychological assessments (66 patients) were performed 1–3 days (baseline) and 6 months after ablation. Immediately after ablation, diffusion-weighted MRI and 3-dimensional double inversion recovery (3D-DIR) detected embolic microinfarctions in 63 patients (87.5%) and 62 patients (86.1%), respectively. After 6 months, DIR lesions disappeared in 41 patients. Microbleeds (MBs) increased by 17%, and 65% of the de novo MBs were exactly at the same location as the microinfarctions. Average Mini-Mental State Examination scores improved from 27.9 ± 2.4 to 28.5 ± 1.7 (p = 0.037), and detailed neuropsychological assessment scores showed improvement in memory, constructional, and frontal lobe functions. Ejection fraction, left atrial volume index and brain natriuretic peptide level improved from baseline to 3–6 months after ablation. Despite incidental microemboli, cognitive function was preserved 6 months after ablation.

Background and Purpose— Cortical microinfarcts (CMIs) are small ischemic lesions found in cerebral amyloid angiopathy (CAA) and embolic stroke. This study aimed to differentiate CMIs caused by CAA from those caused by microembolisms, using 3-Tesla magnetic resonance imaging. Methods— We retrospectively investigated 70 patients with at least 1 cortical infarct <10 mm on 3-dimensional double inversion recovery imaging. Of the 70 patients, 43 had an embolic stroke history (Emboli-G) while 27 had CAA-group. We compared the size, number, location, and distribution of CMIs between groups and designed a radiological score for differentiation based on the comparisons. Results— CAA-group showed significantly more lesions <5 mm, which were restricted to the cortex ( P <0.01). Cortical lesion number was significantly higher in Emboli-G than in CAA-group (4 versus 2; P <0.01). Lesions in CAA-group and Emboli-G were disproportionately located in the occipital lobe ( P <0.01) and frontal or parietal lobe ( P =0.04), respectively. In radiological scoring, ≥3 points strongly predicted microembolism (sensitivity, 63%; specificity, 92%) or CAA (sensitivity, 63%; specificity, 91%). The areas under the receiver operating characteristic curve were 0.85 and 0.87 for microembolism and CAA, respectively. Conclusions— Characteristics of CMIs on 3T-magnetic resonance imaging may differentiate CMIs due to CAA from those due to microembolisms.