Effect of angiotensin converting enzyme inhibitor on chronic ischemic patients

Most of patients with cerebrovascular diseases are associated with hyper-tension. Hypertension induces progressive atheromatous changes in cerebral arteries, and often causes steno-occlusive lesions of cerebral arteries. Angiotensin converting enzyme (ACE) inhibitor cilazapril is one of the antihypertensive drugs. It was reported that cilazapril improved resting cerebral blood flow (CBF) and cerebrovascular reserve capacity (CRC) in experimental studies. In this clinical study, the authors investigated whether long-term treatment with cilazapril could improve CBF and CRC in patients with steno-occlusive lesions of the major cerebral arterial trunk, measured by stable xenon computerized tomography (Xe-CT) with acetazolamide challenge. On the other hand, CBF and CRC in the calcium blocker-treated patients were measured in the same way. CBF did not change after long-term treatment with both cilazapril and calcium blocker. In the cilazapril-treated group, CRC was increased significantly (p < 0.05). However, CRC did not change in the calcium blocker-treated group. It was recognized that long-term treatment with cilazapril did not decrease CBF and improved CRC in patients with occlusive lesions of the major cerebral arterial trunk.     

Modulation of cerebral hemodynamics by surgical revascularization in patients with moyamoya disease

The purpose of this study was to evaluate hemodynamic compromise in the patients with moyamoya discase and surgical modulation of the hemodynamics using stable xenon enhanced computed tomographic CBF measurement with the acetazolamide challenge. The study group consisted of 15 preoperative cases and 17 postoperative cases. In the preoperative group, regional resting cerebral blood flow (rCBF) and regional cerebrovascular reserve capacity (rCRC) were reduced. The reduction was more prominent in the anterior circulation than in the posterior circulation. In the postoperative group, rCBF and rCRC were still low in the anterior circulation. Revascularization increased the resting CBF but did not change the CRC. Postoperative CBF did not increase in adults but increased in children. These findings suggest that the misery perfusion state may be present only in the child's brain. Measurement of CBF and CRC is useful to evaluate the hemodynamics of moyamoya disease.     

Surgical modulation of the natural course of collateral circulation in chronic ischemic patients

The purpose of this study was to evaluate hemodynamic compromise in terms of baseline CBF and CRC in patients with chronic cerebral occlusive lesions and its modulation by a superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis. The study subjects were 10 healthy volunteers and 49 chronic ischemic patients with stenosis or occlusion of the internal carotid artery (ICA) or middle cerebral artery (MCA) The hemodynamics were measured using stable xenon enhanced computed tomographic CBF measurement with the acetazolamide challenge. The compromised hemodynamics in patients with chronic steno-occlusive lesions did not improve during their natural course after two months. STAMCA bypass modulated hemodynamic compromise in the ischemic patients. We recommend STAMCA bypass for patients with reduced CRC, regardless of whether baseline CBF is reduced or normal. Hemodynamic classification using a combination of baseline CBF values and CRC values is useful for evaluating cerebral hemodynamics and for choosing the best treatment for cerebral ischemia with occlusive lesions.     

Regional cerebral blood flow values measured by Xe-CT during the attack of transient global amnesia: a case report]

A 50-year-old right-handed woman was referred to our hospital for further examination of sudden global amnesia. The patient had no history of epilepsy, head injury or cerebral vascular diseases. There were no neurological deficits except for recent memory disturbance. We examined her cerebral blood flow(CBF) immediately during transient global amnesia(TGA) by stable xenon enhanced CT scans(Xe-CT) and twice thereafter. Xe-CT during the attack showed a significant diminution of regional blood flow from the right posterior temporal lobe to the occipital lobe. Conventional MRI scans also had been performed serially but it could not detect the local ischemic event. The ischemic lesion was clearly divided and larger than those cases reported using PET, SPECT, and diffusion-weighted MRI. TGA happens suddenly, and recovery is immediate. It becomes very difficult to study CBF during TGA attack. However stable Xe-CT is capable of examining CBF easily, so we concluded that CBF examination by Xe-CT in TGA patients would be helpful to reveal the mechanism of TGA.     

氙气CT在脑动脉狭窄支架治疗中的应用初探

目的探讨氙气CT在脑动脉狭窄血管内支架治疗中对患者治疗前后的评价作用。方法对10例拟接受脑血管内支架治疗的患者,在术前和术后进行氙气CT检查并予以评价。结果对于患侧脑血流量与对侧正常脑组织血流量比明显降低,但高于10ml/100g/min的患者,给予支架治疗,复查氙气CT示缺血区域脑血流量明显改善,而对于血流量低于10ml/100g/min的患者,给予保守治疗;对于患侧脑血流量与对侧比无明显差异或者有过灌注状况存在的患者,给予保守治疗,患者恢复较好。全部患者随访2个月到1年,均未再有脑血栓临床症状发生。结论氙气CT可定量描述患者狭窄血管供应区域的脑血流量,结合其他检查,可以更好的对接受血管内支架治疗的患者进行风险效益评估。     

Comparison of Xe-CT/CBF and quantitative ECD-SPELT

We compared stable xenon enhanced X-ray computed tomography (Xe-CT) with Technetium-99m ethylsteinate dimer single-photon emission computed tomography (ECD-SPECT) in 12 patients. We evaluated the cerebral blood flow (CBF) values in the territory of the anterior, middle and posterior cerebral artery, and in the thalamus. The CBF values were higher in ECD-SPECT than in Xe-CT except for the values of the thalamus. The posterior cerebral artery territory showed a lower correlation and the thalamus had no correlation between two methods. We discussed causes of these differences.     

Endoscopic evacuation of hypertensive putaminal hemorrhage guided by the 3D reconstructed CT scan: A preliminary report

Objective

The minimally invasive procedure is the trend in nowadays neurosurgical techniques. We designed a new targeting method using three-dimensional (3D) reconstructed CT images combining neuroendoscope for hypertensive putaminal hemorrhage (HPH).

Methods

Eleven consecutive unconscious patients with a significant volume of HPH were treated with neuroendoscope via a selected frontal or temporal trephination. All the CT images were operated and reconstructed by an independent neuroradiologist for measuring the selected frontal or temporal entry point, depth of penetrating path, and surgical trajectory on the basis of the plane formed by bilateral orbitomeatal lines. The nasion and the external auditory meatus were the reference points for the selected frontal and temporal trephinations respectively. All the surgical trajectories were designed as perpendicular to the underground for minimizing the possibility of human errors after aseptic surgical draping. The intra-operatively sonography was routinely used after trephination for confirmation of the planned surgical path and early detection of possible enlarged hematoma.

Results

Ten of the 11 patients regained consciousness postoperatively without complications. All the patients had an accurate trajectory of penetrating path and the average hematoma evacuation rate was 82% (83% for frontal approach and 81% for temporal approach).

Conclusion

Use of the 3D reconstructed CT imaging technique combining neuroendoscope may add as a minimally invasive, economic, and timesaving way for targeting HPH. It also serves as a reliable and useful alternative for hospitals without stereotactic or navigating modalities. However, further prospective studies were needed to clarify its efficacy and safety compared to conventional surgeries.     

Effects of acute percutaneous transluminal recanalization on cerebral embolism

The effects of percutaneous transluminal recanalization (PTR) on critical hemodynamics of cerebral embolism were studied using stable xenon-enhanced computed tomography in patients within 6 hours after onset. PTR was conducted in 10 cases (PTR group) and not conducted 8 cases (non-PTR group). The development of infarction was followed by CT scan. In the cortical arterial regions, the lowest cerebral blood flow (CBF) value in regions of interests (ROIs) without development of infarction was 12.9 ml/100 g/min in the PTR group and 17.0 ml/100 g/min in the non-PTR group. In ROIs with a cerebrovascular reserve capacity (CRC) less than 0 ml/100 g/min, even with a CBF greater than 12.9 ml/100 g/min, 3 of 4 ROIs underwent cerebral infarction. PTR conducted within 6 hours after onset of cerebral embolism would prevent the cortical regions with a CBF greater than 12.9 ml/100 g/min and with a CRC greater than 0 ml/100 g/min from undergoing cerebral infarction.     

Acute cerebral blood flow variations after human cardiac arrest assessed by stable xenon enhanced computed tomography

In this study, changes in cerebral blood flow (CBF) during acute phase after cardiopulmonary arrest (CPA) were examined in patients using stable Xenon enhanced computed tomography (Xe-CT). All patients (8) were stabilized hemodynamically within 4 hours after admission, and Xe-CT was performed immediately after restoration of spontaneous circulation (ROSC) at 8, 24, 48, 96 and 168 hours after ROSC. The progress of patients was monitored in other hospitals and clinics after discharge. Neurological outcomes were evaluated using the Glasgow outcome scale (GOS) 6 months after admission, and scores were compared against changes in CBF. Patients were grouped by prognosis. Four patients belonged to Group A (good recovery) and Group B (2 severely disabled, 2 in persistent vegetative state). The pattern of change in CBF after ROSC was found to be significantly different between Groups A and B (p <0.05). The CBF ratio relative to normal controls was higher in Group B than Group A within 48 hours after ROSC. However, at 48, 96, and 168 hours after ROSC, the opposite was observed: The CBF ratio was significantly higher in Group A than Group B (p<0.05). Based on these results, we concluded that CBF in the patients who survived after CPA changed remarkable especially within the first week. Furthermore, patients with abnormally low CBF that returns to supernormal within the first 48 hours following CPA can be expected to recover well neurologically.     

Differences in acetazolamide vasoreactivity in patients with acute and chronic occlusion of the internal carotid artery.

Using a xenon-enhanced computed tomography (Xe-CT) system, we measured cerebral blood flow (CBF) and acetazolamide vasoreactivity in 3 major vascular territories, the thalamus and putamen on both sides in 3 groups of patients undergoing the balloon occlusion test (BOT), with internal carotid occlusion (ICO) and with open carotids.In the ICO group, although the CBFs on the occluded side were similar to those in the BOT group, the vasoreactivity was significantly higher. The CBFs on the contralateral side were lower than those in the BOT group, but the vasoreactivity was similar. The vasoreactivity of the MCA on the occluded side mostly correlated with that in the other areas, similar to the results obtained in the open carotid group, although it was poorly correlated with other areas in the BOT group. Carotid artery occlusion may reduce CBF in a large area with restoration of vasoreactivity in the chronic stage.     

The effect of glycerol on local cerebral blood flow in patients with chronic ischemic cerebrovascular lesions]

The effect of glycerol on local cerebral blood flow was examined in patients with chronic ischemic cerebrovascular diseases (CVD). Twelve patients with minor completed stroke (10 cases) or transient ischemic attacks (2 cases) were subjected to the study (8 males, 4 females, the age ranging 27 to 70 with average of 56 +/- 15 years). Cerebral blood flow (CBF) was measured with stable xenon computerized tomography (Xe-CT). Each patient had 3 sequential Xe-CTs; resting, with intravenous administration of 200 ml of glycerol (group A) or lactated Ringer's solution (group B), and with intravenous administration of 1 g of acetazolamide. The resting CBF, CBF with glycerol, and CBF with acetazolamide were 30.4 +/- 1.6 ml/100 g/min (ml), 35.1 +/- 2.6 ml, 44.2 +/- 2.2 ml in group A, and 29.9 +/- 2.0 ml, 28.5 +/- 1.9 ml, 45.0 +/- 3.2 ml in group B, respectively. Glycerol increased CBF significantly in patients with chronic CVD, and seemed to be effective in ameliorating chronic low perfusion state in these patients.     

Regional cerebral blood flow of the basal ganglia and thalamus measured using Xe-CT]

Cerebral blood flow (CBF) images obtained using Xe-CT have a much higher spatial resolution than SPECT or PET images. The regional CBF (rCBF) of deep brain regions, the basal ganglia and thalamus, was able to be measured using Xe-CT in 6 subjects. Average rCBF was 87.1 +/- 20.7 ml/100 g/min in the caudate nucleus, 83.5 +/- 15.8 ml/100 g/min in the putamen, 50.0 +/- 8.7 ml/100 g/min in the globus pallidus and 88.9 +/- 12.4 ml/100 g/min in the thalamus. The average rCBF value of the globus pallidus was lower than the values of the caudate nucleus, putamen and thalamus. These observations may be explained by reduced cellularity of the globus pallidus in comparison to the other regions. SPECT and PET are not able to clearly demonstrate the globus pallidus on CBF images. However, precise rCBF values can be measured in the globus pallidus using Xe-CT.     

Perihematoma cerebral blood flow is unaffected by statin use in acute intracerebral hemorrhage patients

Statin therapy has been associated with improved cerebral blood flow (CBF) and decreased perihematoma edema in animal models of intracerebral hemorrhage (ICH). We aimed to assess the relationship between statin use and cerebral hemodynamics in ICH patients. A post hoc analysis of 73 ICH patients enrolled in the Intracerebral Hemorrhage Acutely Decreasing Arterial Pressure Trial (ICH ADAPT). Patients presenting <24 hours from ICH onset were randomized to a systolic blood pressure target <150 or <180 mm Hg with computed tomography perfusion imaging 2 hours after randomization. Cerebral blood flow maps were calculated. Hematoma and edema volumes were measured planimetrically. Regression models were used to assess the relationship between statin use, perihematoma edema and cerebral hemodynamics. Fourteen patients (19%) were taking statins at the time of ICH. Statin-treated patients had similar median (IQR Q25 to 75) hematoma volumes (21.1 (9.5 to 38.3) mL versus 14.5 (5.6 to 27.7) mL, P=0.25), but larger median (IQR Q25 to 75) perihematoma edema volumes (2.9 (1.7 to 9.0) mL versus 2.2 (0.8 to 3.5) mL, P=0.02) compared with nontreated patients. Perihematoma and ipsilateral hemispheric CBF were similar in both groups. A multivariate linear regression model revealed that statin use and hematoma volumes were independent predictors of acute edema volumes. Statin use does not affect CBF in ICH patients. Statin use, along with hematoma volume, are independently associated with increased perihematoma edema volume.     

Clinical study of cerebral blood flow in bilateral chronic subdural hematoma measured by 99mTc-HMPAO SPECT]

Cerebral blood flow(CBF) in 34 patients with bilateral chronic subdural hematoma was measured by 99mTc-HMPAO SPECT before operation. The regional CBF was measured in 26 regions of the 10 cortical regions, putamen, thalamus and cerebellar hemisphere on both sides. According to the thickness of subdural hematoma, the thicker hematoma side was measured and examined as the thick hematoma side, and the other side as the thin hematoma side. Thirty four cases with bilateral chronic subdural hematoma were classified into four groups on the basis of clinical symptoms: 13 cases with headache(headache group), 10 cases with hemiparesis(hemiparesis group), 5 cases with tetraparesis(tetraparesis group) and 6 cases with consciousness disturbance or dementia(consciousness disturbance group), and into two groups according to the degree of midline brain shift on MRI: 14 cases of non-shifted group and 20 cases of shifted group. The average CBF of 34 patients in each region indicated a regional CBF reduction in the frontal, parietal and occipital cortices on the thin hematoma side, and in the putamen on the thick hematoma side. In the headache group, the regional CBF reduction on the thin hematoma side was found in the frontal, parietal and occipital cortices compared with the corresponding regions on the thick hematoma side, and in thalamus on the thick hematoma side. In the hemiparesis and tetraparesis groups, there was no statistically significant CBF reduction between the thick and thin hematoma sides. In the consciousness disturbance group, the CBF reduction in whole brain was remarkably significant. By the degree of the midline brain shift, the CBF reductions between the thick and thin hematoma sides were observed. Namely, in the shifted group, the CBF reductions were noted in the frontal, parietal and occipital cortices in the thin hematoma side, and in the putamen in the thick hematoma side. We concluded that the CBF reduction of bilateral chronic subdural hematoma was bilaterally found in the hemiparesis and tetraparesis groups, and which was finally observed in whole brain in the consciousness disturbance group.     

脑供血动脉狭窄支架置入术前后脑血流变化的氙气CT灌注研究

目的 利用氙气CT(Xe-CT)灌注技术分析脑供血动脉狭窄患者支架置人术前后的血流动力学特点,评价支架置人术的疗效及预后.方法 对19例脑供血动脉狭窄患者进行支架置人治疗,并利用Xe-CT进行血流定量评价,对比术前、术后低灌注区面积及脑血流量改善程度.结果 所有患者术前缺血区脑血流量(CBF)不同程度降低,术后血流量值显著改善;低灌注区域面积减小.结论 脑供血动脉狭窄时,脑组织存在易导致脑梗死的缺血区域,支架置人术可明显改善患者的血流动力学,其疗效可以通过Xe-CT灌注成像得到客观、准确的评价.     

Three-dimensional reconstructed CT scanning for targeting hypertensive putaminal hemorrhage.

We developed an accurate frontal targeting method for hypertensive putaminal hemorrhage (HPH) using three-dimensional (3D) reconstructed CT scanning. Five consecutive unconscious patients with a significant volume of HPH were treated neuroendoscopically via frontal trephination. CT images were examined and reconstructed by an independent neuroradiologist for measuring the selected frontal entry point, depth of penetrating path, and surgical trajectory on the basis of the plane formed by the bilateral orbitomental lines delineated on the reconstructed 3D CT images. All patients regained consciousness post-operatively without complications. All had an accurate trajectory of penetrating path and the average percentage hematoma evacuation was 84%. Use of the 3D reconstructed CT imaging technique combined with neuroendoscopy may prove valuable as a minimally invasive and time-saving method of targeting HPH. Using this method, no further CT scanning is needed for subsequent surgical planning.     

Clinical study of cerebral blood flow in unilateral chronic subdural hematoma measured by 99mTc-HMPAO SPECT]

Cerebral blood flow (CBF) measured by 99mTc-HMPAO SPECT before operation was studied in 60 patients with unilateral chronic subdural hematoma. The regional CBF was measured in 26 regions of the fronto-occipital 10 cortices, putamen, thalamus and cerebellar hemisphere on both sides. Sixty cases with unilateral chronic subdural hematoma were classified into four groups on the basis of clinical symptoms: 17 cases with headache (headache group), 34 cases with hemiparesis (hemiparesis group) and 9 cases with consciousness disturbance or dementia (consciousness disturbance group), and into three groups on the basis of the degree of midline brain shift on MRI: 7 cases of mild shift group, 24 cases of moderate shift group and 29 cases of severe shift group. The average CBF in 60 patients in each region indicated that the regional CBF was reduced in frontal, occipital cortices and cerebellum on the non-hematoma side, and in putamen and thalamus on the hematoma side. In the headache group, the regional CBF reduction on the non-hematoma side was found in only frontal and occipital cortices compared with the corresponding regions on the hematoma side. In the hemiparesis group, the regional CBF was reduced in frontal and occipital cortices on the non-hematoma side and in putamen and thalamus on the hematoma side. The part of CBF reduction in both hemispheres was also noted in the hemiparesis group. In the consciousness disturbance group, the CBF reduction was markedly noted in whole brain. The CBF reductions in frontal and occipital cortices on the non-hematoma side and in putamen, thalamus and cerebellum on the hematoma side was not mutually related with the degree of midline brain shift. We concluded that the disturbance of CBF in chronic subdural hematoma was started from frontal and occipital cortices on the non-hematoma side observed in the headache group, and which was extended to putamen and thalamus on the hematoma side and a part of both hemispheres observed in the hemiparesis group. And such disturbance was finally observed as the CBF reductions in whole brain in the consciousness disturbance group.     

Evaluation of cerebral hemodynamics with perfusion CT]

We report on the evaluation of cerebral ischemic lesions with perfusion CT. Cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) of 52 patients mostly with ischemic cerebrovascular disease were analysed using the box-modulation transfer function method with 30 ml of contrast medium intravenously injected at 5 ml/sec. CBF, CBV and MTT of the middle cerebral artery (MCA) territory were 43.5 +/- 4.6 ml/100 g/min, 1.9 +/- 0.2 ml/100 g and 2.9 +/- 0.6 seconds at the unaffected side, and 37.7 +/- 7.3 ml/100 g/min, 2.1 +/- 0.3 ml/100 g, 3.7 +/- 0.9 seconds at the lesion side with stenosis or occlusion in the main MCA trunks or internal carotid artery, respectively. A statistically significant difference was shown in CBF and MTT values. Furthermore, there was a close correlation in CBF values of MCA territories between Xe-CT and perfusion CT (r = 0.645, n = 76, p < 0.0001). MTT showed a positive correlation with CBV in those subjects when MTT was below 4.1 seconds (r = 0.526, p < 0.0001, n = 83). MTT also showed a negative correlation with CBF in those patients when MTT indicated more than 4.1 seconds (r = 0.818, p < 0.001, n = 21). These results suggest that the progression of cerebral ischemia may be classified in 4 stages using perfusion CT. The stages are as follows: stage 0; normal CBF without prolonged MTT and increased CBV, stage 1; relatively increased CBV, stage 2; significantly prolonged MTT, and stage 3; significantly decreased CBF with prolonged MTT.     

无症状性脑梗塞患者脑血流灌注的相关研究

目的:探讨无症状性脑梗塞(Slient Cerebral lnfarction,SCl)患者的脑血流灌注状况,确定监测病情变化的有效手段。方法:采用Diamox药物负荷,99mTc-ECD SPECT核素显像技术,对20例SCI患者及15例正常对照组进行静态时及负荷后脑血流定量测定。结果:1、静态显像时,SCI组大脑平均脑血流量、额、颞、顶叶皮质及基底节区局部脑血流较对照组轻度降低(P<0.05),负荷后与对照组相比血流降低更加明显(P<0.01);2、危险因素种类个数与SCI患者平均脑血流变化呈有意义的负相关(r=-0.5648,P<0.05)。结论:SCI患者脑血流灌注处于低下状态,脑血管代偿能力降低;2、危险因素的累积作用进一步降低SCI患者的血流灌注;负荷脑血流定量检测技术能客观地反映SCI的脑循环动态情况,可作为有效的病情监测手段。     

重型脑创伤患者脑细胞间液甘油浓度研究

目的研究重型脑创伤后影响脑细胞间液甘油(Gly)浓度变化的因素。方法连续监测53例重型颅脑创伤患者近损伤区脑细胞间液Gly浓度和局部脑血流(CBF),同时监测颅内压(ICP)及脑灌注压(CPP)。选择每小时CPP和CBF的最小值及ICP的最大值与该小时的Gly浓度匹配。根据局部CBF、ICP、CPP及预后将所有Gly样品分组。结果(1)Gly、CCP及CBF与预后的关系:与中残或重残组比较,植物生存或死亡组患者Gly显著增高而CCP及CBF显著降低(P<0.05);与恢复良好组比较,中残或重残组Gly显著增高而CCP及CBF显著降低(P<0.05)。(2)ICP,CCP,CBF对Gly的影响:ICP>15mmHg组、CCP<70mmHg组及CBF<50AU分别比ICP<15mmHg组、CCP>70mmHg及CBF50￣150AU组Gly浓度显著增高(P<0.01)。(3)病理类型和Gly浓度的关系:弥漫性轴索损伤Gly浓度最高,比硬膜外血肿及硬膜下血肿显著增高(P<0.05),但与脑挫裂伤患者无显著差异。结论Gly浓度可以反映原发和继发性脑损伤的严重程度,是细胞膜降解和脑缺血的可靠指标。