CT perfusion parameter values in regions of diffusion abnormalities

BACKGROUND AND PURPOSE: Dynamic CT perfusion imaging is a rapid and widely available method for assessing cerebral hemodynamics in the setting of ischemia. Nevertheless, little is known about perfusion parameters within regions of diffusion abnormality. Since MR diffusion-weighted (DW) imaging is widely considered the most sensitive and specific technique to examine the ischemic core, new knowledge about CT perfusion findings in areas of abnormal diffusion would likely provide valuable information. The purpose of our study was to measure the CT-derived perfusion values within acute ischemic lesions characterized by 1) increased signal intensity on DW images and 2) decreased apparent diffusion coefficient (ADC) and compare these values with those measured in contralateral, normal brain tissue. METHODS: Analysis was performed in 10 patients with acute middle cerebral artery territory stroke of symptom onset less than 8 hours before imaging who had undergone both CT perfusion and DW imaging within 2 hours. After registration of CT perfusion and DW images, measurements were made on a pixel-by-pixel basis in regions of abnormal hyperintensity on DW images and in areas of decreased ADC. RESULTS: Significant decreases in cerebral blood flow and cerebral blood volume with elevated mean transit times were observed in regions of infarct as defined by increased signal intensity on DW images and decreased ADC. Comparison of perfusion parameters in regions of core infarct differed significantly from those measured in contralateral normal brain. CONCLUSION: CT perfusion findings of decreased cerebral blood flow, mean transit time, and cerebrovascular volume correlate with areas of abnormal hyperintensity on DW images and regions of decreased ADC. These findings provide important information about perfusion changes in acute ischemia in areas of diffusion abnormality.     

CT灌注扫描在脑肿瘤的临床应用

目的:研究颅内良恶性肿瘤多层螺旋CT各灌注参数的改变和肿瘤良恶性和脑内外肿瘤的鉴别诊断。方法:41例患者行脑血流的CT灌注扫描,其中脑内肿瘤26例(胶质瘤6例、脑脓肿2例、脑转移瘤17例、淋巴瘤1例),脑外肿瘤15例(颅骨转移瘤2例、垂体瘤7例、脑膜瘤2例、肉芽肿3例、蛛网膜囊肿1例)。应用去卷积算法模式计算相应病变区域的血流量(BF)、血容量(BV)、平均通过时间(MTT)、毛细血管通透性(PS)。根据不同肿瘤的相关参数图来评价良恶性肿瘤血流动力学状态。结果:41例脑肿瘤患者中,脑外肿瘤的CBF、CBV和PS明显高于脑内肿瘤,脑内肿瘤的恶性程度越高其CBF和PS越高,而MTT值与良性肿瘤组织无显著差异。结论:灌注参数CBF、CBV和PS可有效的评价脑肿瘤的血流状态,在脑部良恶性病变及脑内外肿瘤的鉴别诊断上有重要的临床应用价值。     

320排动态容积CT全脑灌注成像技术在脑梗死中的临床应用

目的:探讨320排动态容积CT全脑灌注成像技术在脑梗死诊断中的优势及临床应用价值。方法:对42例脑梗死患者行CT全脑灌注成像,一次对比剂注射得到平扫容积图像、CT血管成像图像及全脑灌注图像,综合运用这三种检查方法全面评估脑梗死。结果:42例脑梗死患者共发现18例存在缺血半暗带(IP),其中8例超急性期6例存在IP,19例急性期8例存在IP,15例亚急性期4例存在IP。42例梗死核心区与健侧对应区比较,脑血容量(CBV)、血流量(CBF)、平均通过时间(MTT)及达峰时间(TTP)值差异均具统计学意义(P<0.05)。18例IP区与梗死核心区比较,CBV、CBF、MTT及TTP值差异均具统计学意义(P<0.05),与健侧对应区比较,CBV值差异无统计学意义(P>0.05)。结论:急性期及亚急性期脑梗死仍可能存在IP。应用320排容积CT全脑灌注成像,对脑梗死患者可明确其责任血管的狭窄部位及程度,了解病变范围及有无IP存在,实现对脑梗死的全面评估。     

Diffusion-negative stroke: a report of two cases

Diffusion-weighted MR imaging is generally thought to be highly sensitive for the diagnosis of acute stroke. We report two cases of hyperacute stroke with absence of changes on diffusion-weighted images within 4 hours of symptom onset. Follow-up studies, performed 4 days later, showed infarction in regions compatible with the clinical presentation and (in one case) with the initial perfusion deficit. These cases indicate that normal findings on diffusion-weighted images in patients with suspected cerebral ischemia do not rule out impending infarction.     

老年多发性脑梗死诊断中MRI与CT影像检查的应用研究

目的分析在多发性的脑梗死老年患者中行核磁共振(MRI)和CT诊断的价值。方法纳入2018年1-12月多发性脑梗死老年患者50例,全部患者都分别实施核磁共振(MRI)和CT,比较两种方式诊断情况。结果 MRI组阳性检出率为96.00%显著高于CT组检出率78.00%,差异有显著性意义(P<0.05);在50例多发性脑梗死患者中,经病理诊断证实有150个病灶,其中脑室旁有20个、顶叶15个、脑干10个、额叶20个、颞叶10个、基底结节40个、丘脑30个、小脑5个;CT诊断与核磁共振诊断的颞叶、脑室旁对于差异不显著(P>0.05);MRI诊断的顶叶、脑干、额叶、基底结节、丘脑、小脑准确率明显要比CT诊断的高,对比差异有显著性意义(P<0.05)。结论在多发性的脑梗死老年患者中行核磁共振(MRI)效果显著。     

64层螺旋CT脑灌注成像评价急性脑梗死溶栓前后脑血流动力学改变

目的探讨64层螺旋CT脑灌注成像(CTP)在评价急性脑梗死溶栓疗效中的应用价值。资料与方法20例急性脑梗死患者于发病3~10h行常规CT平扫和CTP检查,其中16例行静脉溶栓、4例行动脉溶栓治疗。溶栓后2~7天复查CT平扫和CTP。对溶栓治疗前后病变区的脑血流量(CBF)、脑血容量(CBV)和达峰时间(TTP)进行定性和定量比较分析。结果20例中5例头颅CT平扫发现早期脑梗死征象,15例常规CT平扫未发现异常,CTP均发现与临床症状对应的脑灌注异常区,表现为CBF、CBV降低,TTP延迟。溶栓后15例脑灌注异常范围缩小,CBF和CBV增加,TTP缩短;3例脑灌注异常区范围扩大,CBF、CBV进一步降低,TTP延迟更加显著;2例出现局部过度灌注。统计学分析结果显示溶栓治疗后多数患者脑灌注情况明显改善,缺血边缘区CBF和TTP与溶栓前差异有统计学意义(P<0.05),缺血中心区CBF和CBV与溶栓前差异无统计学意义(P>0.05)。结论脑CTP检查能够观察溶栓治疗前后脑血流动力学指标的变化,为评价急性脑梗死患者的溶栓疗效提供重要依据。     

256层螺旋CT全脑灌注联合CTA在急性脑梗死诊断中的价值

目的 探讨256层MSCT全脑CTP与CTA技术相结合在急性脑梗死中的应用价值,并评估脑梗死与供血动脉状况的关系.方法 对21例临床拟诊急性脑梗死患者行常规CT平扫、CTP和CTA检查,重建并分析CT平扫图像、CTP及CTA图像,所有病例在CTP检查后24h内进行MRI＋ DWI检查.结果 21例脑梗死患者CTA发现33条动脉不同程度狭窄及闭塞,其中包括轻度狭窄4例,中度狭窄13例,重度狭窄7例,闭塞9例.21例患者CTP发现32处梗死灶,脑梗死中心区及周边区rCBF下降、TTP延长的差异在统计学上有显著性意义.结论 256层螺旋CT全脑CTP联合CTA扫描方法简便,可对缺血后脑组织供血动脉状况及血流动力学改变进行有效评价.     

MR扩散加权成像对急性脑梗死的诊断价值

目的 :评价磁共振扩散加权成像 (MRDWI)及ADC图对急性脑梗死的诊断价值。方法 :对 18例疑有急性脑梗死患者行MRDWI检查并分析其ADC图 ,并与CT及常规MRI进行比较。结果 :常规MRI、DWI及ADC图显示所有 18例脑梗死患者的 42个急性梗死病灶 ,而常规MRI只显示了其中 19个病灶。 18例患者中有 3例于MRI检查前行CT扫描 ,仅1例提示急性脑梗死 ,且为大脑中动脉供血区大面积脑梗死。结论 :MRDWI对于急性脑梗死的诊断明显优于CT及常规MRI,并且能够鉴别急性、亚急性和慢性脑梗死     

Computed tomography perfusion imaging in acute stroke

The development of thrombolytic and neuroprotective agents for the treatment of acute stroke has created an imperative for improved imaging techniques in the assessment of acute stroke. Five cases are presented to illustrate the value of perfusion CT in the evaluation of suspected acute stroke. To obtain the perfusion data, a rapid series of images was acquired without table movement following a bolus of contrast medium. Cerebral blood flow, cerebral blood volume and mean transit time were determined by mathematically modelling the temporal changes in contrast enhancement in the brain and vascular system. Pixel-by-pixel analysis allowed generation of perfusion maps. In two cases, CT-perfusion imaging usefully excluded acute stroke, including one patient in whom a low-density area on conventional CT was subsequently proven to be tumour. Cerebral ischaemia was confirmed in three cases, one with an old and a new infarction, one with a large conventional CT abnormality but only a small perfusion defect, and one demonstrating infarct and penumbra. Perfusion CT offers the ability to positively identify patients with non-haemorrhagic stroke in the presence of a normal conventional CT, to select those cases where thrombolysis is appropriate, and to provide an indication for prognosis.     

Comprehensive imaging of ischemic stroke with multisection CT.

Computed tomography (CT) is an established tool for the diagnosis of ischemic or hemorrhagic stroke. Nonenhanced CT can help exclude hemorrhage and detect "early signs" of infarction but cannot reliably demonstrate irreversibly damaged brain tissue in the hyperacute stage of ischemic stroke. Further evaluation of patients with ischemic stroke should include differentiation between reversible and irreversible brain damage, which is essential for choosing an appropriate therapy. Perfusion CT provides information about brain perfusion, which permits differentiation of irreversibly damaged brain tissue from reversibly impaired "tissue at risk." CT angiography can help detect stenosis or occlusion of extra- and intracranial arteries. Multisection CT allows the combined use of all three imaging modalities-nonenhanced CT, perfusion CT, and CT angiography-to rapidly obtain comprehensive information regarding the extent of ischemic damage in acute stroke patients. Specific patterns of findings are typically seen in ischemic stroke and can be analyzed more accurately with the combined use of multisection CT and MR imaging. Nevertheless, prospective studies involving a large number of patients will be needed to ascertain the treatment of choice for patients with each of these patterns of findings.     

可控性大鼠急性脑局部缺血模型的建立及CT灌注成像与病理学评价

目的 建立稳定、可控的脑局部缺血动物模型，并通过CT灌注成像和病理学方法对其进行评价。方法 雄性Wistar大鼠28只，随机分为4组(假手术组、脑梗死15min组、脑梗死30min、再灌注1h组及低灌注6h组)，每组7只鼠。在激光多普勒血流仪监测下采用改良的线栓法制作可控性脑局部缺血动物模型。利用CT灌注成像对各组动物模型的缺血状态进行观察，并与光学显微镜、电子显微镜结果以及红四氮唑(TTC)染色标本对照。结果 脑梗死15min组在激光多普勒血流仪监测下将局部脑血流量(rCBF)控制为5％～22％，CT灌注成像显示7只大鼠局部脑血流量均下降，TIC染色呈浅红色，未见明确梗死病灶，病理学检查显示部分神经元变性和星形细胞肿胀。脑梗死30min再灌注1h组在激光多普勒血流仪监测下将rCBF控制为4％～23％，病理学检查显示7只大鼠脑缺血灶内星形细胞肿胀明显，可见大量神经元变性，标本TTC染色所示的白色梗死区与CT灌注成像异常区域一致。在低灌注6h组，由于rCBF下降程度较小(为38％～55％)，病理学显示7只大鼠星形细胞肿胀明显而神经元变性轻微，TTC染色未见明确梗死病灶。假手术组7只大鼠均未见上述各种异常表现。结论 可控性大鼠急性脑局部缺血模型稳定可靠，能模拟出不同灌注程度的缺血状态，除了可用于脑梗死的研究外，更适用于脑梗死前期的急性脑局部缺血的研究。功能CT灌注成像是评价急性脑局部缺血模型的1种准确、敏感的方法。     

脑SPECT灌注显像在老年人脑血管疾病中的应用

目的：旨在研究脑SPECT血流灌注显像对老年脑血管疾病的诊断价值。材料和方法：对132例脑血管疾病患者进行脑SPECT血流灌注显像，并将SPECT结果与MRI、CT相比较。结果：脑梗塞患者96．1％有阳性发现，有些灌注减低灶较MRI，CT显示的范围大．可能由于包括了梗塞区及周围缺血半影区的缘故。对神经机能联系不能征象进行了观察．短暂性脑缺血发作患者在发作间期有61.9%阳性．病灶与发作期临床症状相符。脑供血不足、脑动脉硬化、脑出血的阳性率分别为64.3%、80%．95.5%。结论：脑SPECT灌注显像为老年人脑血管疾病的诊断提供了客观依据，有重要应用价值。     

超急性期及急性期脑梗死全脑CT灌注和CT血管造影研究

目的评价全脑CT灌注成像加同步CT血管造影(CTA)对早期缺血性脑梗死的诊断价值。方法对20例缺血性卒中发作2~24h病例分别行常规非强化CT(NCCT),CT全脑灌注成像(PWCT)及灌注后70s的延时扫描(DCT),分别测量低灌注区中心,周边及健侧相对应区CT值,计算病变中央和对侧灌注血液容积(PBV),PWCT作为CTA源图像重建CTA,判断颅内大血管阻断或狭窄及分支缺损情况,灌注延时相了解侧支循环改变,PWCT用密度差法处理,1周至1个月后复查CT、MR确定最终梗死区面积,用SPSS软件统计分析。结果20例缺血性卒中NCCT+PWCT+CTA未发现异常10例,其中临床及复查CT、MR证实短暂性脑缺血发作(TIA)6例,腔隙性梗死4例,10例PWCT低灌注区中心、周边内侧与外侧和健侧对应区CT值比较差异具有统计学意义(P<0·01),而病灶中心、周边内和外之间差异无统计学意义(P>0·05),病变侧和健侧PBV值差异有统计学意义(P<0·05),所有最终梗死区面积较低灌注区增大,增大百分比与缺血时间呈中度负相关,R2=0·42,CTA显示左大脑中动脉阻断2例,左大脑中动脉前、中分支缺如3例,NCCT、PWCT及CTA的敏感度分别为28·5%、71·4%和35·7%,延时相显示不对称充盈血管5例。结论CT全脑灌注像加同步CTA对早期脑梗死的诊断不失为一种简便、省时和有效的方法,可明确低灌注区的存在及其大小、位置和相对应供血动脉的情况,对半暗带区也可作出一定程度的推测,可为临床早期溶栓治疗提供半定量的形态学依据。     

CT脑灌注与血管造影在急性脑梗死中的临床应用

目的:探讨64层螺旋CT脑灌注成像和脑血管造影技术在急性期脑梗死中的应用价值。方法:应用PhilipsBrilliance CT 64,对30例发病12h内急性脑缺血患者行CT平扫、CT脑灌注成像(CTP)和CT血管造影(CTA)检查。分析平扫及灌注成像表现,计算出缺血区脑血流参数,包括:脑血容量图(CBV)、血流量图(CBF)、对比剂平均通过时间(MTT)和对比剂峰值时间(TTP),与对侧相应区灌注参数进行比较,并重建颈段和脑内动脉CTA图像。所有病例在发病后3~14天复查CT平扫。结果:30例患者中16例头颅平扫发现早期脑梗死征象,14例常规平扫未发现异常,而CTP均发现灌注异常区。CTP表现为CBF及CBV减低、MTT及TTP延迟;患侧CBF、MTT、TTP与对侧差异有显著性意义(P<0.01),患侧CBV与对侧差异无显著性意义(P>0.01)。重建CTA图像显示16例一侧颈内动脉狭窄,8例一侧大脑中动脉狭窄(其中1例伴大脑后动脉狭窄、左侧后交通动脉闭塞);4例左侧大脑中动脉闭塞,2例左侧颈内动脉闭塞。结论:CTP能够早期、及时、准确地反映缺血部位及程度,预测半暗带;CTA可以显示病变血管的部位和程度;联合应用两者,对早期诊断急性脑缺血和指导治疗有重要价值。     

系统性红斑狼疮脑病的CT诊断(附8例报告)

目的评价CT对系统性红斑狼疮脑病的诊断价值。方法对经临床证实的10例系统性红斑狼疮脑病的CT表现作回顾性分析。结果8例CT表现异常、其中4例表现为双额叶、3例表现为双顶、枕叶弥漫性低密度影，以累及脑白质为主，并累及部分脑皮质及基底节区，分布对称；另1例表现为多发性腔隙性脑梗塞。结论CT对脑部病变的显示有较高的敏感性，对系统性红斑狼疮脑病的诊断、治疗有一定的指导意义，但该病CT表现无特异性，必须密切结合临床方能做出正确诊断。     

急性期脑内血肿3.0T MR扩散加权成像表现

目的:探讨3.0T MR设备中平面回波扩散加权成像(EPI-DWI)和表观扩散系数(ADC)图对急性脑内血肿的诊断价值及与脑梗死的鉴别诊断能力。方法:对18例急性期脑内血肿患者行EPI-DWI检查,获得ADC图并与CT及常规MRI进行对比。同期选择发病时间、病变体积相近的急性脑梗死患者18例,比较急性期脑内血肿与脑梗死的MRI表现。结果:所有急性期脑内血肿在EPI-DWI及ADC图上均为混杂信号,尤其是较大血肿;不同大小血肿周边均可见低信号环。所有急性脑梗死病变均未见周边环状低信号。结论:血肿周边低信号环为急性期脑内血肿的特异性DWI表现,可资与急性脑梗死相鉴别。     

CT灌注成像在脑梗死前期局部低灌注中的应用价值

目的: 探讨脑梗死前期局部低灌注的CT灌注成像的价值.材料和方法: 分析15例临床诊断为脑局部缺血CT平扫和CT增强扫描,常规MRI、MRA及CT灌注成像的表现.结果: 15例CT平扫和增强扫描均未发现新的脑梗死灶,CT灌注成像发现脑梗死前期脑局部低灌注I1期4例、I2期7例、II2期3例,MRI发现缺血灶14个,MRA发现一侧大脑中动脉狭窄2例,一侧大脑中动脉闭塞1例.结论: 脑梗死前期局部低灌注,常规CT,MRI无异常发现.CT灌注成像可超早期发现脑组织局部血流动力学异常,并可分期区分低灌注的脑局部微循环的病理生理学状态,对临床治疗有重要价值.     

Dynamic CT perfusion imaging of acute stroke

BACKGROUND AND PURPOSE: Because cerebral perfusion imaging for acute stroke is unavailable in most hospitals, we investigated the feasibility of a method of perfusion scanning that can be performed rapidly during standard cranial CT. Our aim was to identify the scanning parameters best suited to indicate tissue at risk and to measure a perfusion limit to predict infarction. METHODS: Seventy patients who had suffered stroke and had undergone cranial CT 0.5 to 12 hours (median, 3.75 hr) after the onset of symptoms participated in the study. While undergoing conventional CT, each patient received a bolus of iodinated contrast medium. Maps of time to peak (TTP), cerebral blood volume (CBV), and CBF were calculated from the resulting dynamically enhanced scans. These perfusion images were compared with follow-up CT scans or MR images showing the final infarctions. RESULTS: CBF maps predicted the extent of cerebral infarction with a sensitivity of 93% and a specificity of 98%. In contrast, CBV maps were less sensitive and TTP maps were less specific and also showed areas of collateral flow. Infarction occurred in all of the patients with CBF reduction of more than 70% and in half of the patients with CBF reduction of 40% to 70%. CONCLUSION: Dynamic CT perfusion imaging safely detects tissue at risk in cases of acute stroke and is a feasible method for any clinic with a third-generation CT scanner.     

多层CT灌注成像对脑肿瘤瘤周水肿的临床应用研究

目的初步探讨多层CT灌注成像技术及脑肿瘤瘤周水肿区灌注参数在脑肿瘤诊断中的临床应用价值。方法18例已知有脑部肿瘤的患者行16层CT灌注成像扫描,其中脑胶质瘤3例,脑转移瘤9例,脑膜瘤6例。扫描图像应用Perfusion2软件进行灌注成像分析。结果脑膜瘤瘤周水肿区的PS值远大于胶质瘤和转移瘤。结论脑肿瘤瘤周水肿区的MSCT灌注成像有助于脑肿瘤的鉴别诊断。     

磁敏感成像对急性脑梗塞并出血的诊疗价值

目的：探讨磁敏感加权成像技术（SWI）在急性脑梗塞合并脑出血的影像学特征,阐述SWI技术在急性脑梗塞的临床应用价值。方法：对48例急性脑梗塞患者进行CT、常规MRI、MRA、DWI、及SWI的自身对比研究。CT与磁共振检查间隔不超过12h,常规MRI、MRA、DWI、及SWI检查均同时进行。相关数据分析进行统计学处理。结果：48例脑梗塞中,SWI发现18例合并不同程度的脑出血,而CT、常规MRI、DWI均未见明确脑出血征象;DWI中有5例信号不均匀,结合SWI作回顾性分析考虑合并出血可能。CT显示脑梗塞34例;常规MRI显示40例;DWI显示48例;SWI显示39例,且病灶范围较DWI小,边缘模糊。SWI显示38例梗死区静脉血管减少;6例无变化;4例增多。13例MRA表现为大脑前、中、后动脉不同程度狭窄、闭塞或分支血管减少。结论：SWI技术对显示脑梗塞合并脑出血有特异性表现,且有评价梗塞区脑组织存活性的潜在价值,对指导临床治疗脑梗塞有着重大意义,应列为诊断急性脑梗塞的检查常规。