Cerebral Blood Flow Hypoperfusion Research Articles

Alteration of intracranial blood perfusion in temporal lobe epilepsy, an arterial spin labeling study

BackgroundA critical necessity before surgical resection in mesial temporal lobe epilepsy (mTLE) is lateralizing the seizure focus in the temporal lobe. This study aimed to investigate the differences in perfusion pattern changes in right and left mTLE. Methods42 mTLE patients (22 left and 20 right mTLE) and 14 controls were surveyed with pulsed arterial spin labeling at 3.0 T. The mean cerebral blood flow (CBF) and asymmetry index (AI) were calculated in the bilateral temporal lobe, amygdala, hippocampus, parahippocampus, and nine bilateral vascular territories ROIs. The alterations in whole-brain CBF were identified using statistical parametric mapping (SPM). ResultsCBF decreased in ipsilateral sides in both epilepsy subcohorts, with right mTLE showing a significant difference in most ROIs while left mTLE exhibiting no significant change. CBF comparison of left mTLE and controls showed a significant drop in ROI analysis in left middle temporal and left intermediate posterior cerebral artery and in AI analysis in parahippocampus, distal anterior cerebral artery, distal middle cerebral artery, and intermediate anterior cerebral artery. CBF hypoperfusion was seen in ROI analysis in the left intermediate anterior cerebral artery, left middle temporal, right middle temporal, left superior temporal in the right mTLE compared to controls. Left mTLE CBF differed significantly from right mTLE CBF in right distal middle cerebral artery ROI and AI of proximal middle cerebral artery. ConclusionOur result revealed that mTLE affects extratemporal regions and both mTLE subcohorts with different perfusion patterns, which may enhance the performance of preoperative MRI assessment in lateralization procedures.

Identifying cerebral microstructural changes in patients with COVID-19 using MRI: A systematic review.

Coronavirus disease 2019 (COVID-19) is an epidemic viral disease caused by a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Despite the excessive number of neurological articles that have investigated the effect of COVID-19 on the brain from the neurological point of view, very few studies have investigated the impact of COVID-19 on the cerebral microstructure and function of the brain. The aim of this study was to summarize the results of the existing studies on cerebral microstructural changes in COVID-19 patients, specifically the use of quantitative volumetric analysis, blood oxygen level dependent (BOLD), and diffusion tensor imaging (DTI). We searched PubMed/MEDLINE, ScienceDirect, Semantic Scholar, and Google Scholar from December 2020 to April 2022. A well-constructed search strategy was used to identify the articles for review. Seven research articles have met this study's inclusion and exclusion criteria, which have applied neuroimaging tools such as quantitative volumetric analysis, BOLD, and DTI to investigate cerebral microstructure changes in COVID-19 patients. A significant effect of COVID-19 was found in the brain such as hypoperfusion of cerebral blood flow, increased gray matter (GM) volume, and reduced cortical thickness. The insula and thalamic radiation were the most frequent GM region and white matter tract, respectively, that are involved in SARS-CoV-2. COVID-19 was found to be associated with changes in cerebral microstructures. These abnormalities in brain areas might lead to be associated with behaviors, mental and neurological alterations that need to be considered carefully in future studies.

Salvianolic acid A relieves cognitive disorder after chronic cerebral ischemia: Involvement of Drd2/Cryab/NF-κB pathway

Chronic cerebral ischemia (CCI) refers to long-term hypoperfusion of cerebral blood flow with the main clinical manifestations of progressive cognitive impairment. The pathological mechanism of CCI is complex, and there is a lack of effective treatments. Salvianolic acid A (SalA) is a neuroprotective extract of Salvia miltiorrhiza with the effects of anti-inflammation and anti-apoptosis. In this study, the effect of SalA on cognitive function and Drd2/Cryab/NF-κB signaling pathway in rats with CCI was investigated. Morris water maze and open field test were used to observe the effects of SalA on the cognitive function of CCI rats. The pathological changes in the brain were observed by HE, Nissl, and LFB staining. TUNEL staining, enzyme-linked immunosorbent assay, and western blot analysis were used to detect the inflammatory and apoptosis in the cortex and hippocampus. The expression of Drd2/Cryab/NF-κB pathway-related molecules and Drd2 localization were detected by western blotting and dual immunofluorescence, respectively. SH-SY5Y cells were exposed to chronic hypoglycemic and hypoxic injury in vitro, and Drd2 inhibitor haloperidol was used to verify the involved pathway. The results showed that SalA could improve the cognitive function of CCI rats, reduce pathological damage of cortex and hippocampus, inhibit neuroinflammation and apoptosis, and suppress the activation of NF-κB by regulating Drd2/Cryab pathway. And SalA inhibited NF-κB activation and nuclear translocation in SH-SY5Y cells by upregulating Drd2/Cryab pathway, which was reversed by haloperidol interference. In conclusion, SalA could relieve CCI-induced cognitive impairment in rats, at least partly through the Drd2/Cryab/NF-κB pathway.

Effects of "Tongdu Tiaoshen" acupuncture on cerebral blood flow in patients with high risk of cerebral ischemic stroke based on ASL and PWI technique

To observe the effects of "Tongdu Tiaoshen" acupuncture on cerebral blood flow in high-risk patients of cerebral ischemic stroke based on arterial spin labeling (ASL) and perfusion-weighted imaging (PWI), and to evaluate the clinical efficacy. A total of 180 patients with transient ischemic attacks (TIA) / minor ischemic stroke (MIS) were randomly divided into an acupuncture A group, an acupuncture B group and a medication group, 60 cases in each group. The patients in the acupuncture A group were treated with "Tongdu Tiaoshen" acupuncture at Baihui (GV 20), Fengfu (GV 16), Yamen (GV 15), Dazhui (GV 14), Shenzhu (GV 12), Zhiyang (GV 9), Mingmen (GV 4), Yaoyangguan (GV 3) and Jingjiaji (EX-B 2), once a day; the patients in the acupuncture B group were treated with identical acupoints but was given once every other day; the patients in the medication group were treated with oral administration of nimodipine tablets, 30 mg, three times daily. All the three groups were treated for four weeks. ASL and PWI, including relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), relative mean transit time (rMTT) and relative time to peak (rTTP), were conducted before and after treatment; the changes of the test indexes were compared before and after treatment. The clinical efficacy of the three groups was compared. Compared before treatment, the numbers of ASL normal perfusion in the 3 groups were significantly increased after treatment (all P<0.01); the number of ASL normal perfusion in the acupuncture A group was higher than that in the acupuncture B group (P<0.05), but was not significantly different from that in the medication group (P>0.05). Compared before treatment, rCBV and rCBF in the 3 groups were significantly increased after treatment (all P<0.01), and rMTT and rTTP were significantly reduced (all P<0.01). After treatment, rCBV and rCBF in the acupuncture A group were higher than those in the acupuncture B group (all P<0.05); the rMTT and rTTP in the acupuncture A group were lower than those in the acupuncture B group (all P<0.05); the differences of PWI parameters after treatment were not statistically significant between the acupuncture A group and medication group (all P>0.05). The total effective rate was 88.3% (53/60) in the acupuncture A group, 73.3% (44/60) in the acupuncture B group and 90.0% (54/60) in the medication group; the total effective rate in the acupuncture A group was superior to that in the acupuncture B group (P<0.05), but was not significantly different from that in the medication group (P>0.05). "Tongdu Tiaoshen" acupuncture could effectively improve the hypoperfusion of cerebral blood flow in patients with high risk of cerebral ischemic stroke, reduce the incidence of severe CIS; acupuncture for once a day is better than once every other day.

Clinical use of ictal SPECT in secondarily generalized tonic–clonic seizures

Partial seizures produce increased cerebral blood flow in the region of seizure onset. These regional cerebral blood flow increases can be detected by single photon emission computed tomography (ictal SPECT), providing a useful clinical tool for seizure localization. However, when partial seizures secondarily generalize, there are often questions of interpretation since propagation of seizures could produce ambiguous results. Ictal SPECT from secondarily generalized seizures has not been thoroughly investigated. We analysed ictal SPECT from 59 secondarily generalized tonic-clonic seizures obtained during epilepsy surgery evaluation in 53 patients. Ictal versus baseline interictal SPECT difference analysis was performed using ISAS (http://spect.yale.edu). SPECT injection times were classified based on video/EEG review as either pre-generalization, during generalization or in the immediate post-ictal period. We found that in the pre-generalization and generalization phases, ictal SPECT showed significantly more regions of cerebral blood flow increases than in partial seizures without secondary generalization. This made identification of a single unambiguous region of seizure onset impossible 50% of the time with ictal SPECT in secondarily generalized seizures. However, cerebral blood flow increases on ictal SPECT correctly identified the hemisphere (left versus right) of seizure onset in 84% of cases. In addition, when a single unambiguous region of cerebral blood flow increase was seen on ictal SPECT, this was the correct localization 80% of the time. In agreement with findings from partial seizures without secondary generalization, cerebral blood flow increases in the post-ictal period and cerebral blood flow decreases during or following seizures were not useful for localizing seizure onset. Interestingly, however, cerebral blood flow hypoperfusion during the generalization phase (but not pre-generalization) was greater on the side opposite to seizure onset in 90% of patients. These findings suggest that, with appropriate cautious interpretation, ictal SPECT in secondarily generalized seizures can help localize the region of seizure onset.

Serial Magnetic Resonance Imaging and Single Photon Emission Computed Tomography Study of Acute Disseminated Encephalomyelitis Patient after Japanese Encephalitis Vaccination

We report a 5-year-old mentally retarded Japanese boy who developed acute disseminated encephalomyelitis (ADEM) two weeks after Japanese encephalitis vaccination (Beijing strain). He presented sudden status epilepticus, fever, and disturbance of consciousness. Initial neuroradiological findings revealed multifocal cortical swellings without any white matter lesions, suggesting the existence of partial encephalitis or focal status epilepticus. On the follow-up neuroradiological examinations, small white matter lesions were identified as having gradually extended in spite of clinical improvement by methylprednisolone pulse therapy. The cortical involvement became temporarily worse along with the extension and delayed appearance of white matter lesions. Single photon emission computed tomography (SPECT) showed marked hypoperfusion of cerebral blood flow (CBF) in the cortical lesions at both the acute and the recovery period. The serial neuroradiological findings indicated involvement of white matter and gray matter regions at different stages of the illness and a delay between the onset of symptoms and the appearance of ADEM-associated MR imaging of white-matter lesions.

A Patient of Migraine-like Headache with Amnesia, Pleocytosis and Transient Hypoperfusion of Cerebral Blood Flow

Pseudomigraine with pleocytosis (PMP) is an uncommon disease in Japan. The diagnostic criteria include at least one episode of transient neurological deficit accompanied or followed by migraine-like severe headache, cerebrospinal fluid (CSF) lymphocytosis, and normal neuroimaging. Both the etiology and the pathophysiology of PMP is not yet well defined. We report a 40-year-old man with a PMP-like syndrome. He came to our clinic because of severe throbbing headache and amnesia, and the examination showed CSF lymphocytosis of 23/mm3, a transient decrease of cerebral blood flow in the left thalamus. All the symptoms were completely resolved within 2 months.

Relationship between cholinergic dysfunction and discrimination learning disabilities in Wistar rats following chronic cerebral hypoperfusion

The effects of chronic hypoperfusion of cerebral blood flow (CBF) on central cholinergic indices and intellectual functions were investigated in rats. Male Wistar rats, aged 9 weeks, were anesthetized with pentobarbital, and the bilateral common carotid arteries were permanently ligated. Cortical CBF in the hypoperfused rats was markedly decreased at 6 weeks after the operation. In the hypoperfused group, cholinergic indices were changed to consist two phases after the operation, before (acute) and after (chronic) 6 weeks after the operation. At 6 weeks, choline acetyltransferase activity was restored to the sham-operated level compared with the changes in the frontal cortex and thalamus + midbrain at 3 weeks. On the other hand, the maximum number of muscarinic acetylcholine receptors was reduced in the frontal cortex, hippocampus and striatum at 6 weeks and thereafter remained at this low level. In discrimination learning task, the percentage of correct responses in the hypoperfused rats was generally reduced in contrast with that of the sham-operated rats, although the number of total responses were not changed. As a consequence, cholinergic dysfunctions correlate with discrimination learning disabilities in the hypoperfused rats. These findings suggest that the hypoperfused rat may be useful for the cerebrovascular type dementia model to clarify pathophysiology.

Relationship between cholinergic dysfunction and discrimination learning disabilities in Wistar rats following chronic cerebral hypoperfusion

The effects of chronic hypoperfusion of cerebral blood flow (CBF) on central cholinergic indices and intellectual functions were investigated in rats. Male Wistar rats, aged 9 weeks, were anesthetized with pentobarbital, and the bilateral common carotid arteries were permanently ligated. Cortical CBF in the hypoperfused rats was markedly decreased at 6 weeks after the operation. In the hypoperfused group, cholinergic indices were changed to consist two phases after the operation, before (acute) and after (chronic) 6 weeks after the operation. At 6 weeks, choline acetyltransferase activity was restored to the sham-operated level compared with the changes in the frontal cortex and thalamus + midbrain at 3 weeks. On the other hand, the maximum number of muscarinic acetylcholine receptors was reduced in the frontal cortex, hippocampus and striatum at 6 weeks and thereafter remained at this low level. In discrimination learning task, the percentage of correct responses in the hypoperfused rats was generally reduced in contrast with that of the sham-operated rats, although the number of total responses were not changed. As a consequence, cholinergic dysfunctions correlate with discrimination learning disabilities in the hypoperfused rats. These findings suggest that the hypoperfused rat may be useful for the cerebrovascular type dementia model to clarify pathophysiology.

Chronological SPECT studies of a patient with subacute sclerosing panencephalitis

We describe here chronological single photon emission computed tomography (SPECT) with N-isopropyl-p-[ 123I]iodoamphetamine ( 123I-IMP) of a patient with subacute sclerosing panencephalitis (SSPE) from the early clinical stages. The case, an 8-year-old Japanese girl, was in clinical stage I of the disease on admission. A SPECT study with 99mTc-hexamethylprophyleamine oxime ( 99mTc-HM PAO) and 123I-IMP revealed hypoperfusion of cerebral blood flow in the bilateral occipital areas and a part of the cerebellum. Initially, no abnormal findings were observed on CT and MRI. Subsequently, however, MRI indicated abnormal signal intensity dominantly in the area of the occipital white matter where hypoperfusion of cerebral blood flow was found by the initial SPECT studies. This abnormal cerebral hypoperfusion appeared to improve after treatment with oral inosiplex and intrathecal interferon-α over 6 months of the clinical course. The abnormal signal intensity on the MRI also decreased, but simultaneous cranial CT demonstrated diffuse cortical atrophy and slight ventricular dilatation.