无症状脑白质疏松患者局部脑血流的定量评估

Quantitative evaluation of regional cerebral blood flow in patients with silent Leukoaraiosis

目的:测定无症状脑白质疏松患者脑血流量以观察患者脑循环、脑功能的变化。方法:采用单光子发射计算机断层显像,99mTc-乙撑双半胱氨酸二乙酯标记,定量测定无症状脑白质疏松患者20例及15例正常老年人的平均脑血流量和局部脑血流量。无症状脑白质疏松患者为2001-08/2003-01大连医科大学附属第一医院神经内科门诊及住院患者,正常老年人为大连医科大学附属第一医院的老年健康体检者,断层前30min口服过氯酸钾200～400mg,以减少脉络丛和唾液腺、甲状腺对显像剂的摄取,避免影响图像的质量。显像剂以肘静脉“弹丸式”注入,即刻进行动态采集。结束后于外耳孔及外眦放置点源,进行脑实质静态采集30s,以确定OM线,进行单光子发射计算机断层采集。对原始数据进行图像重建,得到大脑平均脑血流量后对单光子发射计算机断层定性图像进行Lassen校正,得到定量图像。于横断图像上选取OM线上50mm、60mm、70mm3个层面,在不同脑叶皮质及脑白质疏松区域左右对称设置感兴趣区各20个定量测定局部脑血流量。神经心理测试采用简易智力状态检查,满分30分,<24分判定为痴呆。结果:脑白质疏松组患者20例和对照组正常人15例均完成检查,全部进入结果分析。①无症状脑白质疏松组大脑平均脑血流量、额、颞、顶叶皮质及脑白质疏松区局部脑血流量与对照组比较均明显降低,差异有显著性[(369.1±41.6),(394.2±36.5)mL/(min·g),t=2.30,P<0.05];[(308.6±28.7),(340.8±36.2)mL/(min·g),t=2.56,P<0.05];[(384.9±50.1),(409.8±37.5)mL/(min·g),t=2.23,P<0.05];[(414.1±50.7)、(443.8±52.3)mL/(min·g),t=2.31,P<0.05];[(283.4±33.8),(312.5±34.3)L/(min·g),t=2.49,P<0.05],尤以额叶皮质降低显著。②轻、中、重度无症状脑白质疏松患者大脑平均脑血流量分别为(375.2±17.1),(368.5±32.9),(353.6±47.7)mL/(min·g),3组之间差异无明显统计学意义(F=2.46,P>0.05)。③在对20例无症状脑白质疏松患者进行的神经心理测试中,患者智能评分未达到痴呆的程度,但只有2例满分,其余18例均存在程度不等的计算力及记忆力的下降,显示轻度的脑功能低下。结论:无症状脑白质疏松患者全脑存在广泛的脑血流灌注降低,涉及脑白质疏松区及额、颞、顶叶皮质区域,脑功能处于低下状态。单光子发射计算机断显像脑血流定量测定法可作为无症状脑白质疏松患者病情变化发展及疗效判定的动态监测手段。

AIM： To detect the cerebral blood flow （CBF） of patients with silent Leukoaraiosis to observe the changes of their cerebral circulation and Cerebral function. METHODS： The mean CBF and regional CBF were quantitatively detected with ^99mTc-ECD and consecutive single photon emission computerized tomography （SPECT） in 20 patients with silent Leukoaraiosis and. 15 normal elderly people. The patients with silent Leukoaraiosis were the outpatients or inpatients of the Department of Neurology, the First Affiliated Hospital of Dalian Medical University between August 2001 and January 2003, and the normal elderly people were the elderly healthy physical examinees in this hospital. At 30 minutes before, SPECT, all the subjects orally took potassium perchlorate （200-400 mg） to reduce the uptake of developer by choroids plexus, salivary gland and thyroid gland, in order to avoid affecting the quality of image. The developer was infused via elbow vein in a pellet manner, and dynamic collection was performed immediately. Spot sources were placed at external ear hole and lateral canthus to statically collected cerebral parenchyma for 30 s, so as to define the orbitomeatal （OM） line, and collected with SPECT. The image reconstruction was applied to the original data, and the SPECT image was treated with Lassen correction after the mean CBF was obtained, and then the quantitative image was collected, We selected three transaxial slices above the OM line at 50 mm, 60 mm and 70 mm, respectively, and 20 regions of interest （ROIs） were set symmetrically in different bagal ganglia and different cortex to quantitatively detect the regional CBF. Cognitive function was assessed with mini-mental state examination （MMSE）, and the total score was 30 points, 〈 24 was considerad as dementia. RESULTS： All the 20 patients with silent Leukoaraiosis and 15 normal elderly people finished the examination and entered the analysis of results. （1） The mean CBF, and the regional CBF of frontal, temporal and parietal lobe cortexes and loose area of cerebral white matter in the silent Leukoaraiosis group were all obviously decreased as compared with those in the control group [（369.1±41.6）, （394.2±36.5） mL/g per minute, t=2.30, P 〈 0.05; （308.6±28.7）, （340.8±36.2） mL/g per minute, t=2.56, P 〈 0.05; （384.9±50.1）, （409.8±37.5） mL/g per minute, t=2.23, P 〈 0.05; （414.1 ±50.7）, （443.8±52.3） mL/g per minute, t=2.31, P 〈 0.05; （283.4±33.8）, （312.5±34.3） mL/g per minute, t=2.49, P 〈 0.05], and the decrease of frontal lobe cortex was more significant. （2） The mean CBF was insignificantly different among the patients with mild, moderate and severe silent Leukoaraiosis [（375.2± 17.1）, （368.5±32.9）, （353.6±47.7）mL/g per minute, F=2.46, P 〉 0.05], （3） Of the 20 patients with silent Leukoaraiosis, the score of MMSE did not reach the degree of dementia, but only 2 cases had total score, and,the other 18 cases all had decreases of calculation and memory to different extent, and showed mild cerebral hypofunction. CONCLUSION： Extensive cerebral blood flow perfusion exists in the brain of patients with silent Leukoaraiosis, which was involved in the loose area of cerebral white matter, and frontal, temporal and parietal lobe cortexes, and the patients have cerebral hypofunction. The measurement of CBF by SPECT can be used as an effective way to monitor the progression of diseases and judgement of therapeutic effect in patients with silent Leukoaraiosis.