In animal experiments, ischemic stroke is usually induced through middle cerebral artery occlusion (MCAO), and quality assessment of this procedure is crucial. However, an accurate assessment method based on 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) is still lacking. The difficulty lies in the inconsistent preprocessing pipeline, biased intensity normalization, or unclear spatiotemporal uptake of FDG. Here, we propose an image feature-based protocol to assess the quality of the procedure using a 3D scale-invariant feature transform and support vector machine. This feature-based protocol provides a convenient, accurate, and reliable tool to assess the quality of the MCAO procedure in FDG PET studies. Compared with existing approaches, the proposed protocol is fully quantitative, objective, automatic, and bypasses the intensity normalization step. An online interface was constructed to check images and obtain assessment results.
Animals ; Fluorodeoxyglucose F18 ; Infarction, Middle Cerebral Artery/diagnostic imaging* ; Positron-Emission Tomography/methods*

Diffusion-weighted imaging (DWI) is currently the most sensitive technique to diagnose early ischemic stroke. DWI signal hyperintensity is usually considered to suggest irreversible infarct core, but recent studies demonstrated that DWI hyperintensity signal could be reversible on small embolic lesions. Herein we present a case in a 63-year-old male patient, who was admitted to the emergency department with altered mental status and complaint of weakness in the left arm and leg 6.8 h prior to the admission. Emergency cranial magnetic resonance imaging (MRI) and angiography (MRA) revealed occlusion of his right middle cerebral artery (MCA) and large lesions on DWI. The patient underwent intra-artery thrombectomy after evaluation in spite of the large volume of the DWI lesions up to 91.5 mL at the baseline. His right MCA was recanalized at 8.5 h from symptom onset. One week after the procedure, the patient showed reduced DWI lesion volume to 11.58 mL. In this case we observed the reversibility of a large lesion of the anterior artery circulation presenting with hyperintensity on DWI, suggesting that the clinical implication of DWI hyperintensity should be interpreted with caution, and a large volume of baseline DWI hyperintensity may not be a contraindication to thrombectomy. This conclusion, however, awaits further validation by future large-scale randomized controlled trials.
Diffusion Magnetic Resonance Imaging ; Humans ; Infarction, Middle Cerebral Artery ; diagnostic imaging ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Stroke ; Thrombectomy

PURPOSE: Lacunar stroke, in the context of small vessel disease, is a type of cerebral infarction caused by occlusion of a penetrating artery. Pulsatility index (PI) is an easily measurable parameter in Transcranial Doppler ultrasound (TCD) study. PI reflects distal cerebral vascular resistance and has been interpreted as a surrogate marker of small vessel disease. We hypothesized that an increased PI, a marker of small vessel disease, might be associated with a larger infarct volume in acute lacunar stroke. MATERIALS AND METHODS: This study included 64 patients with acute lacunar stroke who underwent TCD and brain MRI. We evaluated the association between the mean PI value of bilateral middle cerebral arteries and infarct volume on diffusion-weighted MRI using univariate and multivariate linear regression. RESULTS: The mean infarct volume and PI were 482.18±406.40 mm3 and 0.86±0.18, respectively. On univariate linear regression, there was a significant positive association between PI and infarct volume (p=0.001). In the multivariate model, a single standard deviation increase of PI (per 0.18) was associated with an increase of 139.05 mm3 in infarct volume (95% confidence interval, 21.25 to 256.85; p=0.022). CONCLUSION: We demonstrated that PI was an independent determinant of infarct volume in acute lacunar stroke. The PI value measured in acute stroke may be a surrogate marker of the extent of ischemic injury.
Aged ; Cerebral Infarction/*diagnostic imaging/*physiopathology ; *Diffusion Magnetic Resonance Imaging ; Female ; Humans ; Linear Models ; Male ; Middle Aged ; Middle Cerebral Artery ; Pulsatile Flow/physiology ; Retrospective Studies ; Stroke, Lacunar/*diagnostic imaging/*physiopathology ; *Ultrasonography, Doppler, Transcranial ; Vascular Resistance/physiology

Stroke at the acute stage is a major cause of disability in adults, and is associated with dysfunction of brain networks. However, the mechanisms underlying changes in brain connectivity in stroke are far from fully elucidated. In the present study, we investigated brain metabolism and metabolic connectivity in a rat ischemic stroke model of middle cerebral artery occlusion (MCAO) at the acute stage using F-fluorodeoxyglucose positron emission tomography. Voxel-wise analysis showed decreased metabolism mainly in the ipsilesional hemisphere, and increased metabolism mainly in the contralesional cerebellum. We used further metabolic connectivity analysis to explore the brain metabolic network in MCAO. Compared to sham controls, rats with MCAO showed most significantly reduced nodal and local efficiency in the ipsilesional striatum. In addition, the MCAO group showed decreased metabolic central connection of the ipsilesional striatum with the ipsilesional cerebellum, ipsilesional hippocampus, and bilateral hypothalamus. Taken together, the present study demonstrated abnormal metabolic connectivity in rats at the acute stage of ischemic stroke, which might provide insight into clinical research.
Acute Disease ; Animals ; Brain ; diagnostic imaging ; metabolism ; Brain Mapping ; Disease Models, Animal ; Fluorodeoxyglucose F18 ; Glucose ; metabolism ; Infarction, Middle Cerebral Artery ; diagnostic imaging ; metabolism ; Male ; Neural Pathways ; diagnostic imaging ; metabolism ; Positron-Emission Tomography ; Radiopharmaceuticals ; Random Allocation ; Rats, Sprague-Dawley

Extracranial carotid artery occlusive disease is a major cause of ischemic stroke in Caucasians. However, intracranial artery occlusive disease, especially middle cerebral artery (MCA) stenosis is more significant in Asians. The underlying mechanisms of ischemic stroke with intracranial artery occlusive lesions is different from that of extracranial artery it is expected to recognize the pathogenesis and epidemiology of intracranial artery occlusive disease. By digital magnetic resonance angiography (MRA) and transcranial doppler (TCD) instead of traumatic subtract angiography methods for screening diagnosis of intracranial artery stenosis that were developed in recent two decades. In current paper, we summarized the results studied with MRA and TCD in Peking Union Medical College Hospital and Chinese University of Hong Kong with literatures reviews in this field. Two aspects are discussed (1) Methods for diagnosis of intracranial artery stenosis; (2) Epidemiology of intracranial artery stenosis.
Angiography, Digital Subtraction ; Carotid Artery, Internal ; diagnostic imaging ; Carotid Stenosis ; diagnosis ; epidemiology ; Cerebral Arteries ; diagnostic imaging ; China ; epidemiology ; Constriction, Pathologic ; diagnosis ; diagnostic imaging ; Humans ; Infarction, Middle Cerebral Artery ; diagnosis ; diagnostic imaging ; Intracranial Arteriosclerosis ; diagnosis ; epidemiology ; Magnetic Resonance Imaging ; Ultrasonography, Doppler, Transcranial

OBJECTIVETo investigate the distribution and clinical manifestations of intracranial arterial occlusive lesions (IAOLs), and their correlation with thyroid function.

METHODSWe enrolled 7 patients who had Graves' disease (GD) with IAOLs screened and evidenced by transcranial Doppler, then further confirmed with digital substract angiography in 2 patients and magnetic resonance angiography in 5 patients. Brain magnetic resonance imaging (MRI) was performed in all 7 patients. Three patients were followed up.

RESULTSAmong 7 patients, 1 was male and 6 were females. The mean age was 32.0 +/- 5.5 (range from 11 to 49) years old. Six of them had symptoms of GD but one was asymptomatic with abnormality of T3, T4, and thyroid stimulating hormone. The lesions of intracranial arteries were symmetrical bilaterally in the internal carotid artery system in 6 patients, as well as asymmetrical in 1 patient Terminal internal carotid artery (TICA) were involved in all 7 patients. Middle cerebral artery (MCA) were involved in 3, anterior cerebral artery in 2, and basilar artery in 1 patient. Net-like collateral vessels and mimic moyamoya disease were observed in the vicinity of the occlusive arteries in 2 patients. All patients presented symptoms of ischemic stroke including transient ischemic attack and/or infarction while IAOLs were found. Three patients had obvious involuntary movements. Brain MRI revealed infarctions located in the cortex, basal ganglion, or hemiovular center in 5 patients. The remaining 2 patients had normal brain MRI. The neurological symptoms were improved concomitant with relief of the thyroid function in 2 patients, while IAOLs were aggravated with deterioration of the thyroid function in 1 patient.

CONCLUSIONIAOLs in patients with GD mainly involve intracranial arteries, especially the TICA and MCA, which is similar to moyamoya disease. The neurological symptoms and severity of involved arteries may relieve while the hyperthyroidism is gradually under control.

Adolescent ; Adult ; Angiography, Digital Subtraction ; Antithyroid Agents ; therapeutic use ; Brain ; diagnostic imaging ; pathology ; Carotid Artery, Internal ; Carotid Stenosis ; complications ; diagnostic imaging ; drug therapy ; Child ; Female ; Follow-Up Studies ; Graves Disease ; complications ; diagnostic imaging ; drug therapy ; Humans ; Infarction, Middle Cerebral Artery ; complications ; diagnostic imaging ; drug therapy ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Ultrasonography, Doppler, Transcranial

Positron emission tomography (PET) imaging of functional metabolism has been widely used to investigate functional recovery and to evaluate therapeutic efficacy after stroke. The voxel intensity of a PET image is the most important indicator of cellular activity, but is affected by other factors such as the basal metabolic ratio of each subject. In order to locate dysfunctional regions accurately, intensity normalization by a scale factor is a prerequisite in the data analysis, for which the global mean value is most widely used. However, this is unsuitable for stroke studies. Alternatively, a specified scale factor calculated from a reference region is also used, comprising neither hyper- nor hypo-metabolic voxels. But there is no such recognized reference region for stroke studies. Therefore, we proposed a totally data-driven automatic method for unbiased scale factor generation. This factor was generated iteratively until the residual deviation of two adjacent scale factors was reduced by < 5%. Moreover, both simulated and real stroke data were used for evaluation, and these suggested that our proposed unbiased scale factor has better sensitivity and accuracy for stroke studies.
Animals ; Computer Simulation ; Disease Models, Animal ; Female ; Fluorodeoxyglucose F18 ; Image Processing, Computer-Assisted ; methods ; Infarction, Middle Cerebral Artery ; diagnostic imaging ; Male ; Positron-Emission Tomography ; methods ; Rats ; Rats, Sprague-Dawley ; Stroke ; diagnostic imaging

This study aimed to investigate inflammatory edema after cerebral ischemia through 7.0T MRI and proton magnetic resonance spectroscopy (MRS). All SD rats were randomly divided into sham operated group and middle cerebral artery occlusion (MCAO)-1 day, -3 day and -7 day groups. MRI scan of the brain was performed on a 7.0 Tesla MRI scanner. The volume of positive signals in the ischemic side was detected by using a T2 weighted spinecho multislice sequence; the changes in the height of water-peak were measured with point resolved spectroscopy (PRESS) sequences; cortical edema was detected by using wet-dry weight method; the degrees of nerve injury were evaluated by Bederson neurological score system; double-labeling immunofluorescence technique was used to explore the molecular mechanisms of post-ischemia cerebral edema. The results showed that high T2WI signals were observed in MCAO-1 day, -3 day and -7 day groups, and the water-peak height and water-peak area of MCAO groups were higher than those of sham operated group (P<0.05). Neurological score results were consistent with the degree of brain edema, and a large number of microglia accumulated in the ischemic cortex. Our results suggested that non-invasive MRI technology with the advantage of high spatial resolution and tissue resolution can comprehensively and dynamically observe inflammatory edema after cerebral ischemia from a three-dimensional space, and contribute to evaluation and treatments in clinic.
Animals ; Brain ; diagnostic imaging ; pathology ; Brain Edema ; diagnostic imaging ; etiology ; Brain Ischemia ; complications ; CD11b Antigen ; metabolism ; Immunohistochemistry ; Infarction, Middle Cerebral Artery ; complications ; Inflammation ; diagnostic imaging ; etiology ; Magnetic Resonance Imaging ; methods ; Magnetic Resonance Spectroscopy ; Male ; Microglia ; metabolism ; Microscopy, Confocal ; Microscopy, Fluorescence ; Radiography ; Rats ; Rats, Sprague-Dawley ; Reproducibility of Results ; Time Factors

OBJECTIVETo study the relationship between carotid atherosclerosis and cerebral infarction (CI).

METHODSBetween November 2008 and March 2009, 147 CI patients (CI group) and 48 patients with non-cerebrovascular diseases (control group) were enrolled from inpatients of Neurology Department of our hospital. The diagnostic criterion of thickened carotid intima was set as 1.0 mm

RESULTSIn the CI group, 36 (24.5%) patients had normal carotid intima, 22 (15.0%) had thickened carotid intima, and 89 (60.5%) had carotid plaque. In the control group, 22 (45.8%) patients had normal carotid intima, 4 (8.3%) had thickened carotid intima, and 22 (45.8%) had carotid plaque. The severity of carotid atherosclerosis in the CI group was higher than that in the control group (P = 0.022). There was significant difference in the constitution of carotid plaque between the two groups (P = 0.001); the CI group mainly had the soft plaque (55/89, 61.8%), whereas the control group mainly had the hard plaque (17/22, 77.3%). The first three common locations of carotid plaque in both groups were carotid bifurcation (CI group: 73.7%; control group: 64.1%), common carotid artery (CI group: 20.4%; control group: 25.6%), and internal carotid artery (CI group: 5.9%; control group: 10.3%). The location of carotid plaque between the two groups was not significantly different (P = 0.438). There was no difference in the carotid inner diameter or resistance index between the two groups (P > 0.05).

CONCLUSIONSCarotid atherosclerosis is to some extent able to reveal the atherosclerotic condition of cerebral arteries and act as an important predictor for the risk of CI. The color Doppler ultrasonography of carotid arteries can provide a convenient way for the prevention and treatment of CI.

Adult ; Aged ; Aged, 80 and over ; Carotid Arteries ; diagnostic imaging ; pathology ; Carotid Artery Diseases ; complications ; epidemiology ; pathology ; Cerebral Infarction ; epidemiology ; etiology ; pathology ; Female ; Humans ; Male ; Middle Aged ; Risk Factors ; Ultrasonography, Doppler, Color