Relationship between cerebrovascular reserve capacity and white matter lesions in the elderly based on magnetic resonance imaging / 中国辐射卫生

Objective To investigate the relationship between cerebrovascular reserve (CVR) capacity and white matter lesions in elderly people. Methods We included 315 participants aged ≥ 60 years in Jinan area of Shandong Province from May 2018 to July 2019. They underwent transcranial Doppler ultrasonography for assessing CVR, breath holding index (BHI), and arterial pulsatility index (PI). According to CVR capacity, they were divided into normal CVR group (CVR ≥ 20%, n = 206) and impaired CVR group (CVR < 20%, n = 109). Magnetic resonance imaging was performed to evaluate periventricular, subcortical, and total white matter hyperintensity (WMH) volumes and Fazekas scores. Results Compared with the normal CVR group, the impaired CVR group showed significantly higher volumes of periventricular, subcortical, and total WMHs and significantly higher proportions of Fazekas scores ≥ 2 (P < 0.01). Periventricular, subcortical, and total WMH volumes were negatively correlated with CVR (r = −0.70, −0.66, −0.73, P < 0.01) and BHI (r = −0.64, −0.65, −0.68, P < 0.01) and positively correlated with PI (r = 0.60, 0.65, 0.65, P < 0.01). After adjusting for confounding factors, periventricular, subcortical, and total WMH volumes were still negatively correlated with CVR and BHI (P < 0.01) and positively correlated with PI (P < 0.01). The logistic regression analysis showed that the risks of periventricular, subcortical, and total Fazekas score ≥ 2 in the impaired CVR group were 1.96 times (95% confidence interval [CI]: 1.17−3.27, P < 0.01), 1.84 times (95% CI: 1.11−3.05, P < 0.05), and 2.33 times (95% CI: 1.30−4.18, P < 0.01) that of the normal CVR group, respectively. Conclusion Impaired CVR is an independent risk factor for white matter lesions in the elderly.

Application of 13N-Ammonia PET/CT Cerebral Blood Perfusion Imaging Combined with Methazolamide Challenge in Ischemic Cerebrovascular Diseases / 中国康复理论与实践

Objective:To apply 13N-ammonia PET/CT cerebral blood perfusion imaging combined with methazolamide challenge for cerebrovascular reserve (CVR) evaluation in ischemic cerebrovascular diseases. Methods:From January, 2014 to December, 2016, 56 ischemic stroke patients with serious stenosis of unilateral internal carotid artery or middle cerebral artery accepted basal and stress PET/CT with methazolamide challenge. The patients were divided into normal-CVR group (n = 29) and reduced-CVR group (n = 27) according to the results of CVR, and followed up for 24 months. The ischemic cerebrovascular events and cerebral blood flow were observed. Results:The incidence of transient ischemic attack was more in the reduced-CVR group than in the normal-CVR group (χ2 = 4.389, P < 0.05), while the incidence of ischemic stroke increased a little with no significant difference between the two groups (P > 0.05). The CBF was improved in normal-CVR group after treatment (t = 2.409, P < 0.05), and the improvement was not significant in reduced-CVR group (t = 0.648, P > 0.05). Conclusion:13N-ammonia PET/CT cerebral blood flow perfusion imaging combined with methazolamide challenge can be used to evaluate CVR to predict the outcome for patients with cerebral ischemic disease, which is helpful for early intervention.

Effect of Modified Bazhentang on Cerebrovascular Reserve and Hemorheology in Patients with Chronic Cerebral Circulation Insufficiency / 中国实验方剂学杂志

Objective: To observe the effect of modified Bazhentang on cerebrovascular reserve and hemorheology in patients with chronic cerebral circulation insufficiency. Method: Totally 80 patients treated at Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine from January 2018 to June 2018 in line with the inclusion criteria were randomly divided into the observation group (40 cases) and the control group (40 cases) using the random sequence of Stata 13.0. Both groups received basic treatments, such as antihypertensive, hypoglycemic and lipid-lowering. In addition to the therapy of the control group, the control group was also given nimodipine tablet treatment, and the observation group was given modified Bazhentang treatment, with a total course of 30 days. Before and after treatment, transcranial doppler ultrasonography (TCD) was used to detect the cerebrovascular reserve function of the two groups, so as to evaluate the clinical efficacy, and detect the hemorheology, blood routine, hepatic and renal function. Result: The effective rate of the observation group was 92.5%, and that of the control group was 80%. The clinical efficacy of the observation group was better than that of the control group (PPPPPConclusion: Modified Bazhentang can effectively treat chronic cerebral circulation insufficiency. By improving the function of cerebrovascular reserve and cerebral blood flow, it can alleviate clinical symptoms without safety problems, so as to provide a theoretical basis for the treatment of chronic cerebral circulation insufficiency with traditional Chinese medicine.

Cerebrovascular Reserve in Patients with Unilateral Internal Carotid Artery or Middle Cerebral Artery Stenosis: Study with 13N-Ammonia PET/CT Combined with Methazolamide / 中国康复理论与实践

@#Objective To evaluate the cerebrovascular reserve (CVR) with 13N-ammonia PET/CT and methazolamide in patients with cerebral ischemic disease. Methods From January, 2014 to December, 2015, basal and stress PET/CT were performed in ten healthy persons and 53 patients with unilateral internal carotid artery or middle cerebral artery stenosis. Radioactive counts were measured on mirror regions of bilateral frontal lobe, parietal lobe, temporal lobe, occipital lobe, basal ganglia and thalamus to calculate the blood flow change rate. Results For the healthy persons, the radioactive distribution of bilateral frontal lobe, parietal lobe, temporal lobe, occipital lobe, basal ganglia and thalamus were roughly symmetrical on both basal and stress PET/CT. The radioactive counts were more in basal ganglia and thalamus than in cortex, and the least in white matter. The radioactive counts were more on stress PET/CT than basal PET/CT, and there was no significant difference between both sides (t=1.552, P=0.132). For the patients, the blood flow perfusion decreased in 39 patients with 126 regions on basal PET/CT, and 49 patients with 183 regions on stress PET/CT. Within the 39 patients who found decreased blood flow perfusion regions, 16 patients were found new regions on stress PET/CT, and 29 regions of 13 patients improved in blood flow perfusion on stress PET/ CT. The blood flow change rate was significantly different between basal and stress PET/CT (t=2.466, P<0.05). Conclusion 13N-ammonia PET/CT cerebral blood flow perfusion imaging combined with methazolamide stress test can evaluate the cerebrovascular reserve in patients with unilateral internal carotid artery or middle cerebral artery stenosis, and is valuable for clinical assessment and early intervention for patients with cerebral ischemic disease.

Effects of cerebrovascular reserve on progress and outcome in patients with internal border zone infarction induced by severe middle cerebral artery stenosis / 临床神经病学杂志

Objective To assess cerebrovascular reserve ( CVR) function in patients with internal border zone infarction(IBZI) induced by severe middle cerebral artery (MCA) stenosis, and investigate the impact on progression and outcome of the disease .Methods A total of 84 patients with unilateral severe MCA stenosis were selected . Hypercapnia was induced by holding breath .The change of blood flow velocity in MCA was measured by transcranial Doppler ( TCD ) to calculate CVR .According to CVR , patients were divided into impaired regional CVR group ( CVR 0.05 ) .Conclusion Impaired regional CVR may be predictive of subsequent progressive cerebral infarction and poor clinical outcomes in patients with IBZI induced by severe MCA stenosis .

Hemodynamic Significance of Internal Carotid or Middle Cerebral Artery Stenosis Detected on Magnetic Resonance Angiography

PURPOSE: We evaluated hemodynamic significance of stenosis on magnetic resonance angiography (MRA) using acetazolamide perfusion single photon emission computed tomography (SPECT). MATERIALS AND METHODS: Of 171 patients, stenosis in internal carotid artery (ICA) and middle cerebral artery (MCA) (ICA-MCA) on MRA and cerebrovascular reserve (CVR) of MCA territory on SPECT was measured using quantification and a 3-grade system. Stenosis and CVR grades were compared with each other, and their prognostic value for subsequent stroke was evaluated. RESULTS: Of 342 ICA-MCA, 151 (44%) presented stenosis on MRA; grade 1 in 69 (20%) and grade 2 in 82 (24%) cases. Decreased CVR was observed in 9% of grade 0 stenosis, 25% of grade 1, and 35% of grade 2. The average CVR of grade 0 was significantly different from grade 1 (p<0.001) and grade 2 stenosis (p=0.007). In quantitative analysis, average CVR index was -0.56+/-7.91 in grade 0, -1.81+/-6.66 in grade 1 and -1.18+/-5.88 in grade 2 stenosis. Agreement between stenosis and CVR grades was fair in patients with lateralizing and non-lateralizing symptoms (kappa=0.230 and 0.346). Of the factors tested, both MRA and CVR were not significant prognostic factors (p=0.104 and 0.988, respectively), whereas hypertension and renal disease were significant factors (p<0.05, respectively). CONCLUSION: A considerable proportion of ICA-MCA stenosis detected on MRA does not cause CVR impairment despite a fair correlation between them. Thus, hemodynamic state needs to be assessed for evaluating significance of stenosis, particularly in asymptomatic patients.

Cerebrovascular reserve capacity of patients with ischemic cerebral white matter lesions / 实用医学杂志

Objective To investigate the changes of cerebrovascular reserve capacity (CVR) in patients with ischemic white matter lesions (WML). Methods 126 patients with WML were divided into mild lesion, moderate lesion, severe WML groups and a normal control group by brain MRI. Blood pressure, blood sugar, blood fat were measured and past medical histories were recorded in details. All the patients were routinely examined using TCD to evaluate CVR. Hypercapnia was induced by inhaling the CO2 they breathed themselves and hypocapnia was done by voluntary hyperventilation. Results Age, hypertension, diabetes mellitus and Apo-A were the independent risk factors for WML. Compared with the controls , CVR decreased significantly in the severe and moderate WML groups (P < 0.05). The extent of WML negatively correlated to the cerebrovascular reserve capacity (rs = -0.273, -0.392). Conclusions Age, hypertension, diabetes mellitus and Apo-A are the independent risk factors for WML. CVR is significantly decreased in the WML.

Study on relationship between changes of cerebrovascular reserve capacity in patients with symptomatic middle cerebral artery ischemia / 重庆医学

Objective To investigate the changes of middle cerebral artery(MCA) in patients with ischemic cerebrovascular re-serve capacity(CVR) and its related factors .Methods 80 patients of MCA stenosis diagnosed by transcranial Doppler(TCD) and (or) magnetic resonance imaging(MRI) were divided into asymptomatic group(n=52) and symptom group(n=28) ,and selected 30 healthy people without cerebral vascular stenosis and stroke risk factors as control group .All subjects underwent TCD combined with breath holding test in patients with CVR ,clinical data were compared in patients with cerebrovascular stenosis ,Logistic appli-cation of single factor and multi factor regression were used to analyed the factors affecting CVR .Results The breath holding index (BHI)of symptom group was 0 .44 ± 0 .14 ,significantly lower than that of the asymptomatic group 0 .75 ± 0 .22 and control group 0 .98 ± 0 .27(P<0 .05) .Patients with smoking index ,symptom group drinking index ,hypertension ,hyperlipidemia ,diabetes ,family history of stroke ,carotid intima-media thickness(IMT) were significantly higher than that in the asymptomatic group(P<0 .05) . Logistic regression analysis showed that smoking ,hypertension ,hyperlipemia ,diabetes ,IMT were associated with BHI(P<0 .05) . Conclusion Symptomatic MCA ischemia in patients with decreased CVR ,CVR changes and smoking index in patients with stroke risk index ,drinking ,hypertension and other factors are related to lower CVR ,and has a certain value in cerebral ischemic event pre-diction .

Clinical significance of transcranial Doppler and end-tidal carbon dioxide partial pressure on cerebrovascular reserve capacity in cerebral vessels stenosis patients / 中国医师进修杂志

Objective To study the clinical significance of cerebrovascular reserve (CVR) capacity in cerebral vessels stenosis (CVS) patients with transcranial Doppler (TCD) and end-tidal carbon dioxide partial pressure (PETCO2).Methods Fifty-two CVS patients were divided into two groups:one blood vessel stenosis group (22 cases) and multi blood vessels stenosis group (30 cases).Forty-five normal persons were selected as control group.All the groups were routinely examined with TCD and PETCO2.Hypercapnia was induced by inhaling the carbon dioxide who breathed himself,and hypocapnia was induced by voluntary hyperventilation to investigate the CVR capacity.Results (1)The vasodilator reserve of affected side of one blood vessel stenosis group [(3.16 ± 2.73)％/mm Hg,1 mm Hg =0.133 kPa],the heavier side of multi blood vessels stenosis group [(2.41 ± 1.25)％/mm Hg],and control group [(3.75 ± 1.77)％/mm Hg] had significant difference (F =3.866,P ＜ 0.05).The vasodilator reserve of heavier side of multi blood vessels stenosis group was significantly lower than that of control group (t =-2.657,P ＜ 0.05).The overall reserve of affected side of one blood vessel stenosis group [(3.13 ± 1.38)％/mm Hg],the heavier side of multi blood vessels stenosis group [(2.01 ± 1.89)％/mm Hg],and control group [(3.51 ±0.92)％/mm Hg] had significant difference (F =5.905,P ＜ 0.05).The overall reserve of heavier side of multi blood vesse stenosis group was significantly lower than that of control group and affected side of one blood vessels stenosis group (t =-3.468,2.582,P ＜ 0.05).(2) There was no significant difference among the 3 groups in PETCO2 when eupnea,hypocapnia and hypercapnia.(3) The extent of vascular disease correlated negatively with the vasodilator reserve and overall reserve (r =-0.433 and-0.475,P＜0.05).Conclusions TCD and PETCO2 are simple,economic and effective methods for assessing CVR capacity.The CVR capacity is reduced in patients with cerebral vessels changes.

Pre- and Post-Angioplasty Perfusion CT with Acetazolamide Challenge in Patients with Unilateral Cerebrovascular Stenotic Disease

OBJECTIVE: Perfusion computed tomography (PCT) has the ability to measure quantitative value and produce maps of mean transit time (MTT), cerebral blood flow (CBF), and cerebral blood volume (CBV). We assessed cerebral hemodynamics by using these parameters and acetazolamide (ACZ) challenge for pre- and post-procedural evaluation in patients with unilateral cerebrovascular stenotic disease. METHODS: Thirty patients underwent pre-procedural PCT with ACZ challenge, and 24 patients (80%) was conducted follow up PCT after angioplasty with same protocol. The mean MTT, CBF, and CBV were measured and compared in both middle cerebral arterial (MCA) territories before and after ACZ challenge. Hemispheric ratio and percent change after ACZ challenge were calculated before and after angioplasty. RESULTS: The mean stenosis rate was 76.6%. Significant increases in MTT (32.6%, p=0.000) and significant decreases in CBF (-14.2%, p=0.000) were found in stenotic side MCA territories. After ACZ challenge, there were significant changes in MTT (37.4%, p=0.000), CBF (-13.1%, p=0.000), and CBV (-10.5%, p=0.001) in pre-procedural perfusion study. However, no significant increases were found in MTT, or decreases in CBF and CBV in post-procedural study. There were no significant changes after ACZ challenge also. In addition, the degrees of these changes (before and after ACZ challenge) were highly correlated with the stenotic degrees in pre-procedural perfusion study. CONCLUSION: PCT with ACZ challenge appears to be a useful tool to assess the cerebral perfusion status especially in patients with unilateral symptomatic stenotic disease.

Study of cerebrovascular reserve capacity in obstructive sleep apnea-hypopnea syndrome / 中国综合临床

Objective To assess cerebrovascular reserve capacity in patients with obstructive sleep apnea-hypopnea syndrome(OSAHS).Methods One hundred and fourteen patients with OSAHS and 43 normal persons were enrolled in this study.The patients were divided into mild,moderate,severe according to apnea hypopnea index (AHI) and LSaO2 (lowest arterial oxygen saturation).All the patients and normal persons were routinely examined using transcranial Doppler (TCD) and end-tidal carbon dioxide partial pressure(ETCO2) to evaluate cerebrovascular reserve.Hypercapnia was induced by inhaling the CO2 which produced by the patients themselves,and hypocapnia was elicited by voluntary hyperventilation.Results CVR in the severe and moderate OSAHS were significantly lower than that in the control group [ (1.80 ± 1.34) ％/mm Hg and (1.43 ±1.05)％/mm Hg vs (2.93 ±0.93)％/mm Hg,P ＜0.05] when patients in the condition of hypocapnia.And there was no significant difference on CRV between the mild OSAHS group and control group [ (2.53 ±1.83 ) ％/mm Hg vs ( 2.93 ± 0.93 ) ％/mm Hg,P ＞ 0.05 ].When patients in the condition of Hypercapnia,CRV in the severe and moderate OSAHS were also significantly lower than that in the control group [ ( 1.83 ±1.32) ％/mm Hg and (1.08 ± 1.00)％/mm Hg vs (3.32 ± 1.53)％/mm Hg,P ＜ 0.05),AHI was negatively correlated with the cerebrovascular reserve at the condition of hypercapnia and hypocapnia (r=-0.665,-0.721; P ＜ 0.05 ).Conclusion Inhaling CO2 is a effective method for assessing CVR.Cerebrovascular reserve capacity is associated with AHI.Reduced CVR causes hemodynamics change being severe hypoxia in the moderate and severe OSAHS.

The study of the cerebrovascular reserve in patients with diabetes or the combined diabetes and cerebral infarction / 中国糖尿病杂志

Objective To assess the association of cerebrovascular reserve(CVR) with diabetes(DM)、hypertensive atherosclerotic lacunar infarction(HALI),hypertension(HT) and diabetic lacunar infarction(DLI) by means of transcranial Doppler ultrasonography (TCD) with breath-holding maneuver.Methods The breath-holding index (BHI), which was the percentage increase in middle cerebral artery(MCA) blood flow velocity as index of CVR assessment,was detected during breath-holding by TCD and breath-holding technique in 30 diabetic patients,30 hypertensive atherosclerotic lacunar infarction patients,30 hypertension patients and 30 diabetic lacunar infarction patients. Results There was significant difference in the ascending rates of Vm and BHI between diabetic group and diabetic lacunar infarction group,diabete lacunar infarction group and hypertensive atherosclerotic lacunar infarction group,hypertension group and diabetic group (all P<0.05). Conclusions Diabetes can more significantly impair CVR than hypertension. Diabetic lacunar infarction can more significantly impair CVR than diabetes. Diabetic lacunar infarction can more significantly impair CVR than hypertensive atherosclerotic lacunar infarction .

The Serial Change of Cerebral Hemodynamics by Vascular Territory after Extracranial-Intracranial Bypass Surgery in Patients with Atherosclerosis of Cerebral Arteries / 핵의학분자영상

PURPOSE: To assess the effect of extracranial-intracranial (EC-IC) bypass surgery on hemodynamic improvement, we evaluated serial regional cerebral hemodynamic change of the middle cerebral artery (MCA) in symptomatic patients with atherosclerotic occlusion of the internal carotid artery (ICA) or MCA using (99m)Tc-ECD acetazolamide stress brain perfusion SPECT (Acetazolamide SPECT). MATERIAL AND METHODS: The patients who had suffered a recent stroke with atherosclerotic ICA or MCA occlusion underwent EC-IC bypass surgery and Acetazolamide SPECT at 1 week before and three to six months after surgery. For image analysis, attenuation corrected images were spatially normalized to SPECT templates with SPM2. Anatomical automated labeling was applied to calculate mean counts of each Volume-Of-Interest (VOI). Seven VOIs of bilateral frontal, parietal, temporal regions of the MCA territory and the ipsilateral cerebellum were defined. Using mean counts of 7 VOIs, cerebral perfusion index and perfusion reserve index were calculated. RESULTS: Seventeen patients (M:F=12:5, mean age: 53+/-2yr) were finally included in the analysis. The cerebral blood flow of the parietal region increased at 1 week (p=0.003) and decreased to the preoperative level at 3-6 months (p=0.003). The cerebrovascular reserve of the frontal and parietal regions increased significantly at 1 week after surgery (p<0.01) and improved further at 3-6 months. CONCLUSION: Cerebrovascular reserve of the MCA territory was significantly improved at early postoperative period after EC-IC bypass and kept improved state during long-term follow-up, although cerebral blood flow did not significantly improved. Therefore, cerebrovascular reserve may be a good indicator of postoperative hemodynamic improvement resulted from bypass effect.

The Clinical Significance of Cerebrovascular Reserve and Its Determination Methods / 国际脑血管病杂志

Cerebrovascular reserve is an important parameter for evaluating cerebrovascular disease,and it has great clinical significance.There are a number of determination methods for cerebrovascular reserve,such as position emission tomography(PET),single photon emission computed tomography(SPECT),Xenon-133 inhalation technique,Xenon CT,perfusion CT, magnetic resonance imaging(MRI),transcranial Doppler(TCD),transcranial harmonic perfusion imaging(HPI),near infrared spectroscopy(NIR),and Laser Doppler vibrometry(LDV), however,there have been no unified criteria up to now.The provocation test that makes cerebral blood flow increase includes CO_2 inhalation test,breath holding test,and acetazolamide test,etc. The article focuses the discussion on the advantages and disadvantages of the above determination methods.

Neurological Improvement after Cranioplasty in Patients with Surgical Bony Defects : The Usefulness of Acetazolamide Activated (99m)Tc-HMPAO SPECT

OBJECTIVE: The purpose of this study is to examine the influence of cranioplasty on dynamics of cerebral blood flow(CBF) and cerebrovascular reserve capacity(CVRC), and to investigate the usefulness of single photon emission computed tomography (SPECT) as a prognostic factor for neurological improvement after cranioplasty. METHODS: Between March 2003 and December 2005, a prospective study was performed on 24 patients who had undergone total 25 cranioplasty operations. Cerebral blood flow velocities in the middle cerebral artery(MCA) and internal carotid artery (ICA) were obtained by transcranial Doppler ultrasonography(TCD). The CVRC was assessed by SPECT in the natural state and after stimulation with 1g of acetazolamide. Neurological improvement after cranioplasty was compared between patients who showed hyperactivity to acetazolamide-activated SPECT (Group 1, n=7) and hypoactivity to acetazolamide-activated SPECT (Group 2, n=17). These measurements were obtained two weeks prior to and two weeks after cranioplasty. RESULTS: The blood flow velocities at the opposite site to the cranioplasty as well as at the cranioplasty site were significantly increased (P<0.05). Compared with Group 2, there was significant increase in CBF and neurological imrovement after cranioplasty in Group 1. CONCLUSION: Among patients with surgical bony defects, the patients who had normal reactivity of the CVRC showed a significant increase in CBF and neurological improvement after cranioplasty. The authors suggest that CVRC measurement prior to surgery may be an important prognostic factor for neurological improvement after cranioplasty.

Prediction of Cerebrovascular Reserve by the MRI and Doppler Ultrasonography

PURPOSE: We investigated acute stroke patterns on diffusion weighted images and with doppler ultrasonography studies of ICA and MCA steno-occlusive diseases in order to predict the cerbrovascular reserve (CVR), as was measured by acetazolamide (ACZ)-challenged Tc-99m ECD brain perfusion SPECT. MATERIALS AND METHODS: A retrospective analysis was performed of 76 patients who underwent MRI/MRA, ACZ-challenged Tc-99m ECD brain perfusion SPECT, and carotid and vertebral artery Doppler sonography. After dividing these patients into four groups- MCA and ICA steno-occlusions, we analyzed the relationship between the CVR and topologic MR patterns and the flow volume, as was measured by Doppler sonography. RESULTS: The CVRs were preserved in 26 of 76 patients. The CVRs were impaired in those cases of occlusion that were detected on MRA and also by the pattern of the territorial involvement on the diffusion weighted image (p < 0.05, x2 test). Yet in cases of preserved CVRs, the flow volume of the contralateral ICA, the anterior circulation, and the total cerebral flow volume were increased, as was checked by Doppler sonography (p < 0.05, t-test). As calculated by logistic regression analysis, the accuracy for predicting the preserved CVR by using the statistically significant variables was 78%. CONCLUSION: We believe that the MRI-SPECT correlation study was helpful for understanding the hemodynamics and topographic patterns of ischemia in patients with ICA and MCA steno-occlusive disease, and that the flow volume measurement, which was done by using duplex US, was useful for predicting the CVR.

Effectiveness of Bypass Surgery in Treatment and Prevention for Cerebrovascular Occlusive Disease

To study the effect of extracranial-intracranial(EC/IC) bypass on symptomatic patients with hemodynamic cerebral ischemia, we prospectively reviewed 76 patients who underwent EC/IC bypass surgery in patients with occlusive cerebrovascular disease. A series of 76 patients treated in a 7 years period met following criteria. (1) symptomatic internal carotid artery(ICA) or middle cerebral artery(MCA) obstruction or stenosis over 80%. (2) decrease in basal cerebral blood flow(CBF) over 10%. (3) decreased reactivity of CBF in response to acetazolamide. Among these, the types of ischemic episodes were transient ischemic attack(TIA) or reversible ischemic neurological deficit(RIND) in 39, minor stroke in 22, and major stroke in 15. Based on our criteria, superficial temporal artery(STA)-MCA anastomosis was performed in 67 cases and EC-IC bypass grafting using saphenous vein or radial artery in 9. Average follow up period was 26 months(3 months~7 year). Patency of bypass was confirmed by postoperative angiography or magnetic resonence angiography(MRA) in all case except four cases. Of the 72 patients with patiency of bypass, 68 patients(94%) have had an excellent to good outcome with improvement of preoperative neurologic or cognitive dysfunction, 3 patients showed no improvement of preoperative neurologic symptoms and remaining one patient had new developed deficit. All 72 patients with patency of bypass had experienced no further cerebral ischemic events during following period. Postoperative significant improvement of CBF to acetazolamide was showed in 68 cases(94%) of the 72 cases with patency of bypass, while the basal CBF showed significant improved in 31cases. Postoperative permanent neurologic deficit occurred only in one. In view of these finding, the author suggest that EC-IC bypass surgery is a reliable and resonably safe method for establishing new pathways of collateral circulation to the brain and to be considered as an appropriate therapy for improvement of the cerebrovascular reserve capacity in patients with hemodynamic cerebral ischemia, defined using the strict selection criteria employed in this study.

Alterations of Cerebral Blood Flow and Cerebrovascular Reserve in Patients with Chronic Traumatic Brain Injury Accompanying Deteriorated Intelligence / 대한핵의학회잡지

PURPOSE: The purpose of this study was to evaluate alterations of regional cerebral blood flow (CBF) and cerebrovascular reserve (CVR), and correlation between these alternations and cognitive dysfunction in patients with chronic traumatic brain injury (TRI) and normal brain MRI findings. MATERIALS AND METHODS: Thirty TBI patients and 19 healthy volunteers underwen1 rest/acerazolamide brain SPECT using Tc-99m HMPAO. Korean-Wechsler Adult Intelligence scale test was also performed in the patient group. Statistical analysis was performed with statistical parametric mapping software (SPM97), RESULTS: CBF was diminished in the left hemisphere including Wernicke's area in all patients with lower verbal scale scores. In addition, a reduction in CBF in the right frontal, temporal and parietal cortices was related with depressed scores in information, digital span, arithmetic and similarities, In patients with lower performance scale scores. CBF was mainly diminished in the right hemisphere including superior temporal and supramarginal gyri, premotor, primary somatomotor and a port of prefrontal cortices, left frontal lobe and supramarginal gyrus. CVR was diminished in sixty-four Brodmann's areas compared to control. A reduction in CVR was demonstrated bilaterally in the frontal and temporal Iobes in patients with lower scores in both verbal and performance tests, and in addition, both inferior parietal and occipital lobes in information subset. CONCLUSION: Alterations of CBF and CVR were demonstrated in the symptomatic TBI patients with normal MRI finding. These alterations were correlated with the change of intelligence, of which the complex functions are subserved by multiple interconnected cortical structures.

Quantification of Cerebrovascular Reserve Using Tc-99m HMPAO Brain SPECT and Lassen's Algorithm / 대한핵의학회잡지

PURPOSE: For quantitative estimation of cerebrovascular reserve (CVR), we estimated the cerebral blood flow (CBF) using Lassen's nonlinearity correction algorithm and Tc-99m HMPAO brain SPECT images acquired with consecutive acquisition protocol. Using the values of CBF in basal and acetazolamide (ACZ) stress states, CBF increase was calculated. MATERALS AND METHODS: In 9 normal subjects (age: 72+/-4 years), brain SPECT was performed at basal and ACZ stress states consecutively after injection of 555 MBq and 1,110 MBq of Tc-99m HMPAO, respectively. Cerebellum was automatically extracted as reference region on basal SPECT image using threshold method. Assuming basal CBF of cerebellum as 55 ml/100 g/min, CBF was calculated for every pixel at basal states using Lassen's algorithm. Cerebellar blood flow at stress was estimated comparing counts of cerebellum at rest and ACZ stress and Lassen's algorithm. CBF of every pixel at ACZ stress state was calculated using Lassen's algorithm and ACZ cerebellar count. CVR was calculated by subtracting basal CBF from ACZ stress CBF for every pixel. The percent CVR was calculated by dividing CVR by basal CBF. The CBF and percentage CVR parametric images were generated. RESULTS: The CBF and percentage CVR parametric images were obtained successfully in all the subjects. Global mean CBF were 49.6+/-5.5 ml/100g/min and 64.4+/-10.2 ml/100g/min at basal and ACZ stress states, respectively. The increase of CBF at ACZ stress state was 14.7+/-9.6 ml/100g/min. The global mean percent CVR was 30.7% and was higher than the 13.8% calculated using count images. CONCLUSION: The blood flow at basal and ACZ stress states and cerebrovascular reserve were estimated using basal/ACZ Tc-99m-HMPAO SPECT images and Lassen's algorithm. Using these values, parametric images for blood flow and cerebrovascular reserve were generated.

Change of Cerebral Blood Flow Distribution and Vascular Reserve according to Age in Koreans Measured by Tc-99m HMPAO Brain SPECT / 대한핵의학회잡지

PURPOSE: The aim of this study was to evaluate the normal values of regional cerebral blood flow (rCBF) and cerebrovascular reserve (CVR) in normal children to aged volunteers using Tc-99m HMPAO. MATERIALS AND METHODS: Thirty four right-handed normal volunteers (20 males, 14 females, mean age 40.3+/-24.9 years, range 4 to 82 years) were underwent rest/acetazolamide (ACZ) brain SPECT using Tc-99m HMPAO and the sequential injection and subtraction method. rCBF was estimated on the basis of a semiquantitative approach by means of right/left ratio, region/cerebellum and region to whole brain ratios in frontal, parietal, temporal, and occipital lobes, basal ganglia, thalami, and cerebellum. CVR was measured by means of % perfusion increase calculated as % mean count change compared to rest rCBF in each regions. RESULTS: Mean values of right to left ratios range from 1.004 to 1.018. rCBF was highest in cerebellum and lowest in basal ganglia and thalami. Frontal and temporal rCBF decreased while occipital and thalamic rCBF increased according to age. No sexual difference of rCBF was noted. Mean CVR was 29.9+/-12.9%. Mean CVR significantly increased to late teens, and declined thereafter. After 6th decade, CVR in both frontal lobes, left parietal lobe and right basal ganglia decreased significantly with advancing age. There was no sexual difference of CVR. CONCLUSION:: Quantitative assessment of CVR was possible by ACZ Tc-99m HMPAO brain SPECT. It revealed that rCBF and CVR changed according to age in normal Korean volunteers. There was no sexual difference.