• 대한방사선기술학회지:방사선기술과학
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• 제26권3호
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• pp.25-31
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• 2003

급성 허혈성 뇌경색 환자에서 Deconvolution 관류 전산화 단층촬영(computed tomography, CT)의 뇌혈류용적(cerebral blood volume, CBV), 뇌혈류(cerebral blood flow, CBF) 그리고 평균 조영제 통과 시간(mean transit time, MTT) 지도를 확산 강조(Diffusion weighted) MRI과 비교하여 그 유용성을 알아보고자 하였다. 뇌관류 CT와 확산강조 자기공명영상(diffusion weighted MR imaging, DWMRI)을 시행한 급성뇌경색 환자를 대상으로 Deconvolution 기법으로 획득한 CBV, CBF, MTT 지도에서 병변의 면적과 DWMRI의 병변의 면적을 비교 측정하여 일치도를 알아보았다. 또한, 병변 부위와 정상측 대칭부위의 MTT시간을 측정하여 차이를 알아보았다. 본 연구의 모든 예에서 CBV, CBF, 그리고 MTT 세 지도 모두 관류 결손을 인지할 수 있었고, 관류 결손이 인지되는 부위에서 MTT 시간의 현저한 지연이 있었다. 뿐만 아니라, MTT 지도의 결손부위 면적은 DWMRI 보다 크게 나타나 허혈성 패넘브라를 추측할 수 있었다. 결론적으로 Deconvolution 관류 CT의 지도를 이용하면 뇌경색의 조기진단뿐만 아니라 허혈 중심부, 그리고 허혈성 페넘브라를 예측할 수 있어 DWMRI에 비해 관류결손 부위의 혈류 역학적 상태의 평가나 효과적인 치료계획을 세우는데 보다 유용할 것으로 생각된다.

• 한국정보통신학회논문지
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• 제4권1호
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• pp.131-138
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• 2000

This paper works on development of an algorithm for mapping of cerebral perfusion parameters using the gamma-variate curve fitting. The signal intensity variate curve according to time measured in each pixel of perfusion MRI is nonlinear, and various hemodynamic parameters are not computed accurately. Levenberg-Marquardt algorithm(LMA), nonlinear optimum algorithm with high convergent speed and stability, is used to compute them. That is, the signal intensity variate curve is fitted by the gamma-variate function. Various hemodynamic parameters - Cerebral Blood Volume(C.B.V), Mean Transit Time(M.T.T), Cerebral Blood Flow(C.B.F), Time-to-Peak(T.T.P), Bolus Arrival Time(B.A.T), Maximum Slope(M.S) - are computed using LMA.

• 대한디지털의료영상학회논문지
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• 제12권1호
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• pp.27-31
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• 2010

The purpose of this study was to investigated the usefulness of MR perfusion image comparing with SPECT image. A total of pediatric 30 patients(average age : 7.8) with Moyamoya disease were performed MR Perfusion with 32 channel body coil at 3T from March 01, 2010 to June 10, 2010. The MRI sequences and parameters were as followed : gradient Echo-planar imaging(EPI), TR/TE : 2000ms/50ms, FA : $90^{\circ}$, FOV : $240{\times}240$, Matrix : $128{\times}128$, Thickness : 5mm, Gap : 1.5mm. Images were obtained contrast agent administrated at a rate of 1mL/sec after scan start 10s with a total of slice 1000 images(50 phase/1 slice). It was measured with visual color image and digitize data using MRDx software(IDL version 6.2) and also, it was compared of measurement with values of normal and abnormal ratio to analyze hemodynamic change, and a comparison between perfusion MR with technique using Warm Color at SPECT examination. On MR perfusion examination, the color images from abnormal region to the red collar with rCBV(relative cerebral blood volume) and rCBF(relative cerebral blood flow) caused by increase cerebral blood flow with brain vascular occlusion in surrounding collateral circulation advancement, the blood speed relatively was depicted slowly with blue in MTT(Mean Transit Time) and TTP(Time to Peak) images. The region which was visible abnormally from MR perfusion examination visually were detected as comparison with the same SPECT examination region, would be able to confirm the identical results in MMD(Moyamoya disease)judgments. Hymo-dynamic change in MR perfusion examination produced by increase and delay cerebral blood flow. This change with digitize data and being color imaging makes enable to distinguish between normal and abnormal area. Relatively, MR perfusion examination compared with SPECT examination could bring an excellent image with spatial resolution without radiation expose.

• Journal of Korean Neurosurgical Society
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• 제65권6호
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• pp.816-824
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• 2022

Objective : Emergency superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis in patients with large vessel occlusion who fails mechanical thrombectomy or does not become an indication due to over the time window can be done as an alternative for blood flow restoration. The authors planned this study to quantitatively measure the degree of improvement in cerebral perfusion flow using perfusion magnetic resonance imaging (MRI) after bypass surgery and to find out what factors are related to the outcome of the bypass surgery. Methods : For a total of 107 patients who underwent emergent STA-MCA bypass surgery with large vessel occlusion, the National Institute of Health stroke scale (NIHSS), modified Rankin score (mRS), infarction volume, and hypoperfusion area volume was calculated, the duration between symptom onset and reperfusion time, occlusion site and infarction type were analyzed. After emergency STA-MCA bypass, hypoperfusion area volume at post-operative 7 days was calculated and analyzed compared with pre-operative hypoperfusion area volume. The factors affecting the improvement of mRS were analyzed. The clinical status of patients who underwent emergency bypass was investigated by mRS and NIHSS before and after surgery, and changes in infarct volume, extent, degree of collateral circulation, and hypoperfusion area volume were measured using MRI and digital subtraction angiography (DSA). Results : The preoperative infarction volume was median 10 mL and the hypoperfusion area volume was median 101 mL. NIHSS was a median of 8 points, and the last normal to operation time was a median of 60.7 hours. STA patency was fair in 97.1% of patients at 6 months follow-up DSA and recanalization of the occluded vessel was confirmed at 26.5% of patients. Infarction volume significantly influenced the improvement of mRS (p=0.010) but preoperative hypoperfusion volume was not significantly influenced (p=0.192), and the infarction type showed marginal significance (p=0.0508). Preoperative NIHSS, initial mRS, occlusion vessel type, and last normal to operation time did not influence the improvement of mRS (p=0.272, 0.941, 0.354, and 0.391). Conclusion : In a patient who had an acute cerebral infarction due to large vessel occlusion with large ischemic penumbra but was unable to perform mechanical thrombectomy, STA-MCA bypass could be performed. By using time-to-peak images of perfusion MRI, it is possible to quickly and easily confirm that the brain tissue at risk is preserved and that the ischemic penumbra is recovered to a normal blood flow state.

• 대한임상검사과학회지
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• 제36권1호
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• pp.43-48
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• 2004

Cerebral vasoreactivity is an index of autoregulation of cerebral perfusion, and can be measured using functional images such as Xe CT, SPECT and PET in reponse to hypercapneic stimulus. In order to measure cerebral $CO_2$ vasoreactivity in routine TCD study conveniently and reliably, we devised a method of rebreathing into closed volume of reservoir bag as a hypercapneic stimulus, and applied it to 44 healthy volunteers. As a hypercapneic stimulus, we applied fitting mask connected with closed reservoir bag for about 90 seconds, and mean blood flow velocity(MBFV) and pulsatility index(PI) were evaluated at proximal middle cerebral arteries(MCA) of 50-55 mm depth, before and after the hypercapneic stimulus. Age affected the MFV and PI value showed significant and the MFV was 56.45(SD=9.75)cm/sec, while PI was 0.406(SD=0.089). As age increases the flow velocity decreased significantly whereas PI value increased(P<0.05). The vasoreactvity significantly decreased with age(P<0.05). The decrease of cerebral blood flow quantity and cerebral blood flow velocity is not only because of increase of diameter of cerebrovascular resulting from aging, but the resistance increase of small blood vessel resulting from the increase of PI & RI value is regarded. We suppose that the rebreathing method is a reliable and convenient technique as a hypercapneic stimulus in determining cerebral $CO_2$ vasoreactivity. The rebreathing method could be non-invasive and useful methods in estimation of the cerebrovascular reactivity and could be applied to the basal and follow-up evaluation of the cerebrovascular reserve of the ischemic stroke patients.

• 대한방사선기술학회지:방사선기술과학
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• 제32권4호
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• pp.461-469
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• 2009

최근 신경계 질환의 진단에 많이 이용되는 관류자기공명영상기법 중 상대적 뇌 혈류량(relative cerebral blood volume)의 분석에 의한 뇌교종의 악성도 구분(고등급과 저등급 종양의 구분)에 있어 자기공명영상의 뇌 혈류량 검사의 유용성에 대하여 알아보고자 하였다. 뇌교종 환자 17명(평균연령 57.5세, 남자 11명, 여자 6명)을 대상으로 모든 환자에게 수술 전 관류자기공명 영상과 고식적 뇌 자기공명영상을 시행하고, 조직의 병리학적 검사를 시행하였다. 국소적 뇌 혈류량과 상대적 뇌 혈류량의 분석은 지멘스사의 소프트웨어(PAT)와 자체 개발한 영상 후 처리 소프트웨어 Xmap 2.0을 이용하여 비교, 분석하였다. 대상자 17명 중 뇌교종이 저등급인 6명과 고등급인 11명의 관류자기공명영상의 분석 결과는 저등급 뇌교종의 상대적 뇌 혈류량의 백질에 대한 종양부위의 평균 뇌 혈류량(rCBVw)의 평균은 1.62, 피질에 대한 종양부위의 평균 뇌 혈류량(rCBVc)의 평균은 0.12이었다. 고등급 뇌교종의 상대적 뇌 혈류량의 rCBVw의 평균은 33.53, rCBVc의 평균은 0.96이었다. 뇌교종과 반대측 뇌 백질과의 통계적인 상관성은 0.01(p-value)이었고. 뇌교종과 반대측 피질과의 통계적인 상관성은 0.02(p-value)로 나타났다. 결과 중 뇌교종과 뇌 백질의 통계분석수치가 뇌교종과 피질과의 통계분석 결과보다 더 유의한 결과를 나타내었다. 결국 두 가지 모두에서 유의한 결과를 나타냄을 알 수 있었다(p<0.05). 임상적으로 기존의 자기공명영상과 병리학적 결과와 함께 관류자기공명영상은 뇌교종의 등급을 판단하는데 있어 유용할 것으로 사료된다.

• The Korean Journal of Physiology and Pharmacology
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• 제28권3호
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• pp.239-252
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• 2024

Dexmedetomidine displays multiple mechanisms of neuroprotection in ameliorating ischemic brain injury. In this study, we explored the beneficial effects of dexmedetomidine on blood-brain barrier (BBB) integrity and neuroinflammation in cerebral ischemia/reperfusion injury. Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO) for 1.5 h and reperfusion for 24 h to establish a rat model of cerebral ischemia/reperfusion injury. Dexmedetomidine (9 ㎍/kg) was administered to rats 30 min after MCAO through intravenous injection, and SB203580 (a p38 MAPK inhibitor, 200 ㎍/kg) was injected intraperitoneally 30 min before MCAO. Brain damages were evaluated by 2,3,5-triphenyltetrazolium chloride staining, hematoxylin-eosin staining, Nissl staining, and brain water content assessment. BBB permeability was examined by Evans blue staining. Expression levels of claudin-5, zonula occludens-1, occludin, and matrix metalloproteinase-9 (MMP-9) as well as M1/M2 phenotypes-associated markers were assessed using immunofluorescence, RT-qPCR, Western blotting, and gelatin zymography. Enzyme-linked immunosorbent assay was used to examine inflammatory cytokine levels. We found that dexmedetomidine or SB203580 attenuated infarct volume, brain edema, BBB permeability, and neuroinflammation, and promoted M2 microglial polarization after cerebral ischemia/reperfusion injury. Increased MMP-9 activity by ischemia/reperfusion injury was inhibited by dexmedetomidine or SB203580. Dexmedetomidine inhibited the activation of the ERK, JNK, and p38 MAPK pathways. Moreover, activation of JNK or p38 MAPK reversed the protective effects of dexmedetomidine against ischemic brain injury. Overall, dexmedetomidine ameliorated brain injury by alleviating BBB permeability and promoting M2 polarization in experimental cerebral ischemia/reperfusion injury model by inhibiting the activation of JNK and p38 MAPK pathways.

• Journal of Korean Neurosurgical Society
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• 제59권4호
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• pp.346-351
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• 2016

Objective : Early progressive infarction (EPI) is frequently observed and related to poor functional outcome in patients with middle cerebral artery (MCA) infarction caused by MCA occlusion. We evaluated the perfusion parameters of magnetic resonance imaging (MRI) as a predictor of EPI. Methods : We retrospectively analyzed patients with acute MCA territory infarction caused by MCA occlusion. EPI was defined as a National Institutes of Health Stroke Scale increment ${\geq}2$ points during 24 hours despite receiving standard treatment. Regional parameter ratios, such as cerebral blood flow and volume (rCBV) ratio (ipsilateral value/contralateral value) on perfusion MRI were analyzed to investigate the association with EPI. Results : Sixty-four patients were enrolled in total. EPI was present in 18 (28%) subjects and all EPI occurred within 3 days after hospitalization. Diabetes mellitus, rCBV ratio and regional time to peak (rTTP) ratio showed statically significant differences in both groups. Multi-variate analysis indicated that history of diabetes mellitus [odds ratio (OR), 6.13; 95% confidence interval (CI), 1.55-24.24] and a low rCBV ratio (rCBV, <0.85; OR, 6.57; 95% CI, 1.4-30.27) was significantly correlated with EPI. Conclusion : The incidence of EPI is considerable in patients with acute MCA territory infarction caused by MCA occlusion. We suggest that rCBV ratio is a useful neuro-imaging parameter to predict EPI.

• 보험의학회지
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• 제28권1_2호
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• pp.11-14
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• 2009

It is common to find cerebral infarct and hemorrhage without definite neurologic signs but with lesions on neuroimaging. These lesions are called silent lacunar infarct and cerebral microbleed. Silent lacunar infarct are frequently seen in the elderly and are associated with clinically apparent stroke and vascular dementia. Known stroke risk factors, such as hypertension, diabetes mellitus, smoking, hypercholesterolemia and heart problems may increase the risk of silent lacunar infarct. Metabolic syndrome, homocysteinemia, renal failure and intima media thickness(IMT) are also other risk factors of the silent lacunar infarct. Cerebral microbleed, lacunar infarct and intracerebral hemorrhage(ICH) have similar pathology and pathogenesis. So, cerebral microbleed are coexisted with lacunar infarct, leukoaraiosis, hypertensive ICH and vascular dementia. Cerebral microbleed are associated with volume and recurrence of ICH. Also cerebral microbleed may reflect baseline status of blood brain barrior disruption. Silent lacunar infarct and cerebral microbleed are very important to clinical management, but in the aspect of insurance medicine and independent medical examiners, these lesions are not subject of evaluation for handicap.

• 대한본초학회지
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• 제29권1호
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• pp.19-26
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• 2014

Objectives : This study was performed in order to evaluate the effects of Salviae Miltiorrhizae Radix (SMR) water extract against the cerebral hemorrhage and the blood-brain barrier (BBB) impairment in the intracerebral hemorrhage (ICH). Method : ICH was induced by the stereotaxic intrastriatal injection of bacterial collagenase type IV in Sprague-Dawley rats. SMR was orally given three times every 20 hours during 3 days after the ICH induction. Hematoma volume, water content of brain tissue and volume of evans blue leakage were examined. Myeloperoxidase (MPO) positive neutrophils and tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) were observed with immunofluorescence labeling and confocal microscope. Results : SMR significantly reduced the hematoma volume of the ICH-induced rat brain. SMR significantly reduced the water content of brain tissue of the ICH-induced rat brain. SMR reduced the percentage of the evans blue leakage around the hematoma on the caudate putamen compared to the ICH group, especially on the cerebral cortex. SMR significantly reduced the volume of the evans blue leakage level in the peri-hematoma regions of the ICH-induced rat brain. SMR significantly reduced MPO positive neutrophils in the peri-hematoma regions of the ICH-induced rat brain. SMR reduced the TNF-${\alpha}$ expression in peri-hematoma regions of the ICH-induced rat brain. TNF-${\alpha}$ immuno-labeled cells were coincided with MPO immuno-labeled neutrophils in peri-hematoma regions of the ICH-induced rat brain. Conclusion : These results suggest that SMR plays a protective role against the blood-brain barrier impairment in the ICH through suppression of inflammation in the rat brain tissues.