Regional cerebral blood flow in lacunar infarction.

Ten cases of lacunar infarction, 10 cases of nonlacunar cerebral thrombosis, and 8 healthy controls who did not have risk factors of cerebrovascular diseases were studied. Subcortical cystic infarctions with a diameter of less than 1.5 cm were classified as lacunar infarction and the other cerebral thrombosis were classified as nonlacunar cerebral thrombosis. Cerebral blood flow examination by Xenon computed tomography (CT) method was performed within 14 days after the onset of stroke. Stable Xenon was inhaled for 3 minutes and CT scan was taken once before the inhalation, 3 times during the inhalation, and 5 times in the washout phase. Regional blood flows in the infarcted area, around the infarcted area, and in the cerebral cortex and the cerebral white matter where the influence of the infarction was considered to be little were measured before and after intravenous injection of 17 mg/kg acetazolamide. In the lacunar infarction, the blood flow in the cerebral cortex where the influence of the infarction was considered to be little was decreased and the cerebrovascular dilatory reserve capacity in the cerebral cortex and the cerebral white matter was decreased. Arteriolosclerosis is considered to be the basic cause of lacunar infarction.     

Blood flow distribution in cerebral arteries

High-resolution phase–contrast magnetic resonance imaging can now assess flow in proximal and distal cerebral arteries. The aim of this study was to describe how total cerebral blood flow (tCBF) is distributed into the vascular tree with regard to age, sex and anatomic variations. Forty-nine healthy young (mean 25 years) and 45 elderly (mean 71 years) individuals were included. Blood flow rate (BFR) in 21 intra- and extracerebral arteries was measured. Total cerebral blood flow was defined as BFR in the internal carotid plus vertebral arteries and mean cerebral perfusion as tCBF/brain volume. Carotid/vertebral distribution was 72%/28% and was not related to age, sex, or brain volume. Total cerebral blood flow (717±123 mL/min) was distributed to each side as follows: middle cerebral artery (MCA), 21% distal MCA, 6% anterior cerebral artery (ACA), 12%, distal ACA, 4% ophthalmic artery, 2% posterior cerebral artery (PCA), 8% and 20% to basilar artery. Deviating distributions were observed in subjects with ‘fetal'' PCA. Blood flow rate in cerebral arteries decreased with increasing age (P<0.05) but not in extracerebral arteries. Mean cerebral perfusion was higher in women (women: 61±8; men: 55±6 mL/min/100 mL, P<0.001). The study describes a new method to outline the flow profile of the cerebral vascular tree, including reference values, and should be used for grading the collateral flow system.     

Risk factor for cerebral hemorrhage for the patient with lacunar infarction: investigation of 5 cases associated with both of symptomatic hemorrhagic and ischemic strokes]

BACKGROUND AND PURPOSE: Microangiopathy is regarded as an important cause of intracerebral hematoma(ICH) and lacunar infarction. Dot-like low intensity spots on T2-weighted echo planar image(EPI) have been regarded as hemosiderin deposit associated with microangiopathy. However, clinical significance of dot-like hemosiderin spot(dotHS) is still debated. Therefore, we analyzed the number of dotHS on EPI of symptomatic lacunar infarction associated with ICH. METHODS: To investigate how the dotHS or risk factors contributed to hemorrhagic strokes for patients with lacunar infarction, the number of dotHS and various risk factors were made a comparison between 20 cases with symptomatic lacunar infarctions(lacunar group) and 5 cases with both symptomatic lacunar infarction and symptomatic ICH(complicated group). In addition to EPI, fluid attenuated inversion recovery image, and T1- and T2-weighted MR images were performed for differential diagnosis of dot HS. RESULTS: EPI demonstrated that asymptomatic ICH was significantly more frequent in complicated group (60%) than in lacunar group(10%), and dotHS were significantly more frequent in complicated group(100%) than in lacunar group(50%). The number of dotHS of complicated group was 14.6 +/- 4.3, which was significantly larger than that of lacunar group(4.1 +/- 9.2). No significant difference between two groups were founded in other risk factors including hypertension, diabetes mellitus, hyperlipidemia, and smoking. CONCLUSION: These results suggested that dotHS was one of the risk factors for ICH for patients with symptomatic lacunar infarction, and an increasing number of dotHS was one of the predictive factors of symptomatic and/or asymptomatic ICH.     

Are sensorimotor strokes lacunar strokes? A case-control study of lacunar and non-lacunar infarcts.

To determine whether sensorimotor strokes should be considered as lacunar syndromes 34 consecutive patients with first-ever ischaemic sensorimotor stroke were evaluated and compared with 103 patients with non-lacunar infarcts and another 88 patients with lacunar infarcts. Potential thromboembolic sources were more frequent in patients with non-lacunar infarcts (p = 0.003, versus sensorimotor strokes). Although the overall prevalence of hypodense lesions at CT scan was not significantly different among the three groups, lacunar lesions were found in 47.1% of sensorimotor strokes, compared with 6.8% of non-lacunar infarcts (p less than 0.0001). In a mean follow up period of 28.7 months, the incidence of stroke and myocardial infarction among sensorimotor strokes was similar to that of patients with lacunar infarct, but significantly lower than in non-lacunar infarcts (p less than 0.05). These results demonstrate important differences between sensorimotor and non-lacunar infarcts, but quite similar findings in sensorimotor and lacunar strokes, and thus support the theory that sensorimotor strokes are commonly due to lacunar lesions.     

Blood flow velocities in middle cerebral artery branches after subarachnoid hemorrhage.

In a prospective study, 55 patients were examined by transcranial duplex sonography (TCCS) after subarachnoid hemorrhage (SAH) to determine whether additional transcranial duplex examination on the middle cerebral artery M2 segments would aid in the examination of the MCA stem segment. The mean blood flow velocities and pulsatility index were correlated to the occurrence of delayed ischemic neurologic deficits (DIND). Out of 47 patients included, 21 did not experience any delayed deficit (group I), 15 did (group II), and in 11 the extent to which vasospasm contributed to a neurologic deficit was unclear (group III). The highest blood flow velocity and the greatest increase of mean blood flow velocity on 1 day were significantly higher in groups II and III both in M1 and in M2. In 10 patients in group II, where the onset day of DIND was known exactly, Doppler data indicating ischemia before or at the time of DIND were observed in nine. In eight patients, Doppler of the MCA stem alone would have provided enough information to recognize the risk of symptomatic vasospasm; in one patient, only the M2 Doppler gave an indication of ischemic complication. Transcranial duplex sonography may provide additional information to TCD by accurate delineation of M1/M2 vasospasm and therefore may help plan cerebral angiography and neurointerventional treatment.     

Median nerve somatosensory evoked potentials in patients with lacunar and other small subcortical strokes

We recorded median nerve somatosensory evoked potentials (SSEPs) in 42 patients with small subcortical strokes associated with lacunar syndromes. Seventeen patients had abnormal SSEPs. The P22 component was most often affected; changes in N20 and N18 were less common. Four patients with pure motor strokes (PMS) had abnormal SSEPs. Abnormalities of P22 correlated best with motor findings; those of N20 with sensory signs and symptoms. Similar SSEP abnormalities were produced by lesions in various locations. P22 and N20 abnormalities occurred independently and together. We conclude: (1) abnormal SSEPs are common in patients with small subcortical strokes associated with lacunar syndromes, including pure motor stroke; (2) P22 and N20 have separate cortical generators; and (3) P22 may be generated within sensory pathways which are adjacent to or influenced by motor pathways.     

腔隙性脑梗塞患者颅内脑动脉狭窄的检测意义

目的探讨腔隙性脑梗塞与颅内脑动脉狭窄的关系。方法412例腔隙性脑梗塞患者均行经颅多普勒(TCD)检测,发现颅内动脉狭窄后进一步行磁共振血管造影(MRA)检查确诊。结果MRA检查发现颅内动脉狭窄127例。结论腔隙性脑梗塞患者颅内脑动脉狭窄发生率较高,推测其是腔隙性脑梗塞的重要病因。对腔隙性脑梗塞患者应重视检测可能存在的颅内脑动脉狭窄。     

Blood pressure variability in Binswanger's disease and isolated lacunar infarction

To determine whether blood pressure (BP) variability is increased in hypertensive patients with Binswanger's disease (BD), we studied two samples of consecutive treated hypertensive patients: (1) 11 with BD (mean age 71.3 +/- 5.2 years); (2) 16 with lacunar infarction (mean age 65.2 +/- 8.3 years) without cognitive impairment. An averaged baseline office BP was obtained for 3 consecutive weeks. Ambulatory BP monitoring was then carried out to obtain the averaged mean systolic (SBP) and diastolic BP, and BP variability was defined as the standard deviation of consecutive BP values. Results: Diurnal SBP variability was significantly increased in the BD group (p = 0.04). However, with the analysis of covariance for age and baseline office BP, the difference was no longer significant (p = 0.17 and p = 0.09, respectively). We conclude that increased BP variability in BD patients is probably due to older age and increased baseline office BP. Increased BP variability may be a risk factor for small-vessel disease, but not for cognitive impairment.     

Blood pressure does no predict lacunar infarction.

We studied the relation between blood pressure and type of cerebral infarction (large or lacunar) in 134 patients with acute hemispheral infarcts that were detectable by computed tomography and that could not be attributed to causes other than atherothrombotic arterial disease. Lacunae were present in 26 patients, and systolic blood pressures were higher in this group than in the 108 patients with large infarcts. The overlap was so wide, however, that large infarcts predominated at every level of blood pressure. The presence of a lacune can be inferred only from the combination of clinical signs and, most important, computed tomography.