电子束CT增强容积扫描检测早期实验性心肌缺血的方法及…

探讨电子束ＣＴ增强容积扫描检测早期实验性心肌缺血的方法，并报告初步结果。用Ｉｍａｔｒｏｎ Ｃ－１５０型电子束ＣＴ机对冠状动脉结扎后１．５ｈ的５例实验犬进行心脏的碘造影剂增强容积扫描。仔细观察左心室心肌缺血在电子束ＣＴ图像上的形态学表现，测定并对比分析心肌缺血区和正常区的ＣＴ值及两者和左心室腔ＣＴ值的比值。     

犬实验性急性心肌梗死的电子束CT检测

目的 评价电子束ＣＴ（ＥＢＣＴ）增强容积扫描显示犬急性心肌梗死部位、形态密度及大小的价值和限度。方法 结扎６只犬心冠状动脉左前降支及左旋支的分支,拟在左心室壁造成梗死区。结扎后１．５、６、１２、２０小时,分别作ＥＢＣＴ增强容积扫描,得到犬心脏ＣＴ断面图像。完成全部扫描后处死犬,采集心脏电子显微镜和光学显微镜标本作病理检查。仔细分析心肌缺血和梗死在ＥＢＣＴ图像上的形态学表现,测定并比较心肌缺血和梗死     

电子束CT动态扫描检测心肌缺血状态的初步研究

目的运用电子束ＣＴ扫描进行正常组和缺血组的心肌灌注分析，建立心肌灌注检查常规，探讨临床诊断心肌缺血病变的新技术。材料与方法电子束ＣＴ检测心肌灌注２８例，其中１４例为对照组，另１４例为病变组。所有心肌缺血病例皆经单光子发射体层扫描证实。取受检者心短轴，行心电触发，静注造影剂后６秒钟开始动态扫描（ｆｌｏｗｍｏｄｅ）。图像分析注意有无灌注缺损，并根据计算的组织灌注量或血流平均通过时间判断心肌缺血状况。结果每１００ｇ心肌平均血流量在对照组为１３２．６ｍｌ／ｍｉｎ，缺血组为１０６．３ｍｌ／ｍｉｎ。电子束ＣＴ检测心肌缺血病变的敏感性、特异性分别为９６．４％和９２．８％。缺血区灌注曲线的形态与病变的程度、性质密切相关。结论电子束ＣＴ动态扫描是临床进行心肌灌注分析的一项新技术，不但可以诊断心肌缺血病变，还可进一步作出定量、定性方面的评价。     

电子束CT血管造影评价颈动脉狭窄的临床应用

探讨颈动脉电子束ＣＴ血管造影（ＥＢＣＴＡ０的方法并评价其临床价值。材料和方法：使用电子束ＣＴ对５３例病例进行检查。采用Ｉｍａｔｒｏｎ Ｃ－１５０型电子束ＣＴ扫描设备,以２￣４ｍｌ／ｓ前臂静脉注射８０￣９０ｍｌ ０ｍｎｉ￣ｐａｑｕｅ ３００,延迟２０￣３０ｓ后进行连续容积扫描,层厚１．５￣３ｍｍ。将电子束ＣＴ图像转入工作站处理。采用最大密度投影（ＭＩＰ）、表面遮盖显示（ＳＳＤ）、容积再现（ｖｏｕｍｅ     

电子束CT流动检查评价原发性肝癌

目的 应用电子束ＣＴ（ＥＢＣＴ）流动扫描研究原发性肝癌的时间－密度曲线特点与因供和病理的对应关系,以期提高诊断的特异性和准确性。方法 ３１例肝脏肿块者均行ＥＢＣＴ流动扫描。静脉注射对比剂８０￣１００ｍｌ,速度为６￣８ｍｌ／ｓ,病灶区扫描６层,每层扫描１３次,需时１２０秒。画出时间－密度曲线及测量各参数值。结果 ３１例肝癌均表现为不同程度的增强。小于５ｃｍ的肝癌与大于５ｃｍ肝癌和弥漫型肝癌其增强类型     

电子束CT在健康国人心血管正常径线测量及功能值分析中的应用 …

目的 用电子束ＣＴ（ＥＢＣＴ）测量国人心血管正常解剖径线及心功能值，方法 ５０例健康人（男２７例，女２３例，平均年龄４７．７岁）利用ＥＢＣＴ横断和心脏短轴电影扫描，分别测量主动脉，肺动脉，左心房和左心室径线，以及左室心肌厚度，心肌增厚率等，利用心功能分析软件（ｗａｌｌ－ｓｔｕｄｙ），计算左，右室心室各功能指标，结果 得到ＥＢＣＴ心脏电影扫描各主要参数；正常国人主，肺动脉，左心室及心肌径线测量值男性     

增强超高速MRI在犬慢性心肌梗塞的初步应用

目的：应用超高速磁共振成像（ＭＲＩ）观察犬慢性心肌梗塞的心肌灌注。材料与方法：采用聚氯乙烯狭窄器闭胸制备犬慢性心肌梗塞模型。心肌灌注成像的参数包括预备反转脉冲１８０°；ＴＥ２毫秒；ＴＲ４．９毫秒；翻转角８°及采集矩阵６４×６４。静脉注射钆－二乙烯三胺五乙酸（Ｇｄ－ＤＴＰＡ）的同时，在３２秒内获得连续图像。结果：左旋支（ＬＣＸ）或左前降支（ＬＡＤ）致窄术５～１０个月后呈９５％狭窄或闭塞。４条犬左心室壁运动减弱，３条犬为运动消失。在光、电镜下见心肌发生纤维化。注射Ｇｄ－ＤＴＰＡ后，右室、左室及心肌信号逐渐明显增强，正常心肌信号远高于梗塞区心肌（Ｐ＜０．０１）。结论：本研究结果显示Ｇｄ－ＤＴＰＡ增强超高速ＭＲＩ能非创伤地评价心肌缺血     

电子束CT与常规心血管造影计算左心室容积准确性的比较

目的评价电子束ＣＴ（ＥＢＣＴ）及常规心血管造影计算左心室容积的相对准确性。材料与方法对１４只人的左心室铸型进行了ＥＢＣＴ扫描，并与常规双平面Ｘ线电影结果进行比较。左心室铸型的实际容积由铸型排除的水的容积来测定。结果左心室铸型的实际容积为５５．５７±２８．９１ｍｌ，ＥＢＣＴ长轴扫描的计算容积为６６．５０±３３．０４ｍｌ，ＥＢＣＴ短轴扫描的计算容积为６０．３６±２９．９０ｍｌ；常规双平面Ｘ线电影的计算容积为８２．０９±４０．４０ｍｌ。Ｘ线电影计算的左心室容积明显大于ＥＢＣＴ的左心室容积值及左心室铸型的实际容积值（Ｐ＜０．００１）。相关分析表明，ＥＢＣＴ及双平面Ｘ线造影的左心室计算容积值均与左心室铸型的实际容积高度相关（ｒ均高于０．９８）；但双平面Ｘ线电影对左心室容积值的高估程度较ＥＢＣＴ更高（Ｘ线电影为２６．５２±１６．１１ｍｌ，ＥＢＣＴ短轴扫描为４．７９±６．５９ｍｌ，ＥＢＣＴ长轴扫描为１０．９３±８．１４ｍｌ，Ｐ＜０．０１）。结论在左心室容积计算方面，ＥＢＣＴ较常规心血管造影更精确，其同样可以作为左心室容积计算的金标准。     

电子束CT在健康国人心血管正常径线测量及功能值分析中的应用(附50例报告)

目的用电子束ＣＴ（ＥＢＣＴ）测量国人心血管正常解剖径线及心功能值。方法５０例健康人（男２７例，女２３例，平均年龄４７．７岁），利用ＥＢＣＴ横断和心脏短轴电影扫描，分别测量主动脉、肺动脉、左心房和左心室径线，以及左心室心肌厚度、心肌增厚率等；利用心功能分析软件（ｗａｌｓｔｕｄｙ），计算左、右心室各功能指标。结果得到ＥＢＣＴ心脏电影扫描各主要参数；正常国人主、肺动脉、左心房室及心肌径线测量值男性大于女性，但无显著性差异（Ｐ＞０．０５）；左、右心室收缩末容积（ＥＳＶ）、每搏输出量（ＳＶ）、射血分数（ＥＦ）、心排出量（ＣＯ）和心指数（ＣＩ），男性大于女性，但无显著性差异（Ｐ＞０．０５）；左室舒张末容积（ＥＤＶ）和肌块重量（ＭｙＭ），男性大于女性，且有非常显著性差异（Ｐ＜０．００１）。结论ＥＢＣＴ是心血管解剖和心功能值计算的准确定量方法。     

形似脾囊肿的脾结核一例

患者：女,４０岁,左上腹部疼痛一月余,呈持续性阵发性加重,伴恶心、呕吐,无发热、寒战,无盗汗,无黄疸。腹部体检：脾区叩击痛,余无异常。实验室检查：血、尿常规（－）。血生化：白蛋白２８ｇ／Ｌ,球蛋白 ３７ｇ／ Ｌ,白球比例０．７５,谷雨转氨酶８ＩＵ／Ｌ,羟丁酸脱氢酶１４７ＩＵ／Ｌ,其他项目无异常。胸部正侧位片：心、肺、膈无异常。上腹部ＣＴ扫描：脾增大,厚６．５ｃｍ,前部示一类圆形均匀低密度影,占据大部脾脏,病灶大小约 ６．５ｃｍ × ８．０ｃｍ × １３．０ｃｍ,轮廓清楚,ＣＴ值９－１５Ｈｕ。增强后,该…     

DETECTION OF MYOCARDIAL ISCHEMIA BY ELECTRON BEAM CT: Experimental studies

Purpose: To determine if contrast-enhanced electron beam CT (EBCT) can detect areas of acute myocardial ischemia, and if pharmacological stress testing improves the diagnostic accuracy of EBCT.Material and Methods: We injected 0.5 ml/kg and 1.0 ml/kg b.w. of iopromide at a rate of 4 ml/s into the right atrium of 5 ventilated female minipigs at rest and after occlusion of the left anterior descending (LAD) coronary artery. Both ventricles were examined at six short axis levels with an EBCT unit. Myocardial perfusion was calculated from the time-density curves of four left ventricular myocardial segments and the aorta. We also tested the effect of the contrast agent on myocardial density after i.v. administration of 0.6 mg/kg dipyridamole before and after LAD occlusion.Results: At rest, the contrast agent increased myocardial density by 28±2 HU, corresponding to a myocardial perfusion estimate of 67±7 ml/min/100 g. After dipyridamole, myocardial density increased by 29±4 HU. Following occlusion of the LAD, anteroseptal myocardium displayed 10±4 HU density increase. The area of non-enhancement corresponded to ischemic myocardium in stained pathologic sections.Conclusion: Contrast-enhanced stress EBCT can be used to detect areas of myocardial ischemia, and EBCT stress perfusion imaging may be necessary to consistently differentiate ischemic from non-ischemic myocardial tissue.     

Quantitative assessment of myocardial enhancement with iodinated contrast medium in patients with ischemic heart disease by using ultrafast x-ray computed tomography.

BACKGROUND AND RATIONALE. The authors report the quantitation of myocardial enhancement using iodinated contrast medium in patients with ischemic heart disease. Twenty-eight patients with chronic ischemic heart disease and 11 controls were examined by ultrafast computed tomography (CT) using 100-msecond scans. METHODS. The authors analyzed M/L (ratio of post-contrast incremental increases in the left ventricular myocardial and luminal CT number) in early and late phases after contrast injection. RESULTS. In controls, mean values of early and late M/L were 30% and 51%, respectively. In infarcted or severely ischemic segments, early M/Ls (19%, 16%) were significantly small (P less than .001), whereas late M/Ls (90%, 63%) were higher (P less than .001, .01) than controls. Segments with infarction or severe ischemia were differentiated from mild or nonsignificant ischemia by using this parameter (sensitivity, 99%; specificity, 88%). CONCLUSIONS. M/L is useful for detection of the ischemic myocardium.     

Association of early CT abnormalities, infarct size, and apparent diffusion coefficient reduction in acute ischemic stroke

BACKGROUND AND PURPOSE: Diffusion-weighted (DW) imaging is more sensitive for early ischemia than CT, and apparent diffusion coefficient (ADC) mapping permits quantification of the severity of cytotoxic edema. We examined the relationship between early CT findings, ischemic lesion volume on DW images, and edema subtype. METHODS: Patients in whom early signs of ischemia were detected on baseline CT scans were scored CT positive. Baseline DW lesion volumes were compared between the CT-positive and CT-negative patients. In CT-positive patients, we outlined the CT-positive part of the DW lesion and transferred these regions of interest to the corresponding DW sections. The ADC values of the outlined CT-positive areas were then compared with the ADC values of the CT-negative areas within patients. Lesions with significantly increased T2 hyperintensity were excluded to correct for the effect of early vasogenic edema on ADC measurements. RESULTS: Twenty-four patients with cerebral ischemia in whom both CT and DW imaging were performed within 8 hours of symptom onset were entered into the study. Patients with early CT signs of infarction (n = 12) had significantly larger DW lesion volumes than did patients without early CT abnormalities (mean volume, 62.8 versus 14.6 mL; P =. 002). In patients displaying early CT abnormalities, CT-positive regions of the DW lesion had lower relative ADC (rADC) values than did the CT-negative regions, when lesions with significant T2 hyperintensity were excluded (mean rADC, 0.65 versus 0.75; P =.037). CONCLUSION: These findings support the hypothesis that early CT signs of infarction indicate more extensive and severe cerebral ischemia, as reflected by lower ADC.     

电子束CT检出冠状动脉钙化及其与心肌灌注显像的对比研究

目的比较电子束ＣＴ（ＥＢＣＴ）检查冠状动脉钙化（ＣＡＣ）及核素心肌灌注显像（ＭＰＩ）评价冠心病（ＣＨＤ）的价值。材料与方法本组５０例均为临床疑诊或确诊为ＣＨＤ患者。所有患者均行ＥＢＣＴ、ＭＰＩ及冠状动脉造影。结果４０例患者共８４支血管冠状动脉造影证实有明显的冠状动脉病变（ＣＡＤ）（狭窄＞５０％），其中１４例为单支病变，８例为双支病变，１８例为三支病变，另有１０例冠状动脉造影正常。ＥＢＣＴ预测ＣＡＤ的敏感性、特异性及准确性为８３％、８０％及８２％，ＭＰＩ预测ＣＡＤ的敏感性、特异性及准确性分别为８５％、８０％及８４％，ＥＢＣＴ与ＭＰＩ的结果间无显著性差异（Ｐ＞０．０５）。ＣＡＣ血管供血区出现心肌缺血者达６５％。结论ＣＡＣ是预测ＣＡＤ的有价值指标。在有症状的人群中ＥＢＣＴ检出ＣＡＣ预测ＣＡＤ的敏感性、特异性及准确性与ＭＰＩ相似。有症状人群中检出ＣＡＣ患者多有心肌缺血或梗死，因此为早期诊断冠心病，应对无症状人群进行筛选。     

冠心病电子束CT心肌灌注的研究

目的：研究心肌灌注的临床检查方法及其在冠心病诊断中的意义，探讨ＥＢＣＴ测量的临床价值和应用前景。材料和方法：正常组和冠心组各１３例。男女比例１０：３，年龄３３～７３岁，平均５２．８±１０．７。采用电子束ＣＴＩｍａｔｒｏｎＣ－１５０型扫描装置，取心短轴、Ｆｌｏｗ式程序扫描。结果：正常组的心肌灌注与冠心组的心肌灌注量不同，两组间具有显著的统计学差异。但需注意有关测量的影响因素。结论：ＥＢＣＴ是一种测量心肌灌注的新方法，有广阔的应用前景，值得我们继续探讨     

Acute stroke evaluated by time-to-peak mapping during initial and early follow-up perfusion CT studies

BACKGROUND AND PURPOSE: Early diagnosis of perfusion deficits in patients with acute stroke could guide treatment decisions and improve prognosis. We investigated the sensitivity of perfusion CT studies using parametric time-to-peak maps to assess ischemic brain tissue with respect to early infarct signs on native CT scans. METHODS: First-pass, single-section perfusion CT was performed in 20 patients who presented with symptoms of acute stroke within 6 hours of onset. Initial CT perfusion studies were compared with follow-up studies within 30 hours in 10 patients. A manual, region of interest (ROI)-based, local evaluation procedure was performed to determine delayed time-to-peak values and diminished peak amplitudes. In addition, time-to-peak parameter maps were processed off-line from the dynamic CT data sets to identify areas of perfusion deficits, which were expressed as hemispheric lesion areas (HLAs). Evolution of the ischemic regions was assessed by comparing the HLA on the initial and follow-up studies as well as on the native CT scan of the follow-up studies. RESULTS: Diagnostic time-to-peak maps were generated in 19 of 20 initial and in nine of 10 follow-up perfusion CT studies. The initial time-to-peak map showed perfusion deficits in 14 of 20 patients. Hemispheric territorial infarcts were diagnosed with a sensitivity of 93%. Perfusion deficits in two patients with brain stem infarctions and three patients with lacunar strokes were missed. Follow-up time-to-peak maps showed the extent of reperfusion after various therapeutic strategies. CONCLUSION: Perfusion CT is potentially useful for detecting cerebral perfusion deficits in acute ischemic stroke before morphologic changes are observable on native CT scans. Compared with a locally restricted ROI-based evaluation, time-to-peak maps provide sensitive, global indications of malperfused brain areas, facilitate lesion localization, and allow assessment of the evolution of the infarction during follow-up.     

The relationship between coronary artery calcification detected by non-gated multi-detector CT in patients with suspected ischemic heart disease and myocardial ischemia detected by thallium exercise stress testing

OBJECTIVE: To examine whether we could predict myocardial ischemia when coronary artery calcification is detected by non-gated multidetector CT in patients with suspected ischemic heart disease. METHODS: Eighty-three patients suspected of having ischemic heart disease (55 men, 28 women; age range 36-83 years; mean age 68 years) underwent multidetector CT and T1-201 single photon emission computed tomography. Prediction of myocardial ischemia by coronary arterial calcification detected on CT was evaluated by comparing the coronary artery territories that showed calcification with the area of myocardial ischemia determined by SPECT. The sensitivity, specificity, positive predictive value, and negative predictive value of multidetector CT for predicting myocardial ischemia were calculated. Coronary angiography was also examined and compared with multidetector CT. Risk factors, including hypertension, smoking, hyperlipidemia, diabetes, and family history, were compared for evidence of coronary artery calcification detected by multidetector CT and myocardial ischemia detected by thallium nuclear scans. RESULTS: For analysis by patients, the sensitivity, specificity, positive predictive value, and negative predictive value of coronary artery calcification for myocardial ischemia detection were 65, 63, 56, and 71%, respectively. Similarly, for analysis by coronary arterial territories, those values were 56, 77, 41 and 86%, respectively. Coronary stenosis on CAG was also related to the ischemia determined by SPECT and calcification on multidetector CT. Ischemia was better influenced by risk factors than was coronary arterial calcification. CONCLUSIONS: For analysis by coronary arterial territories, the specificity and negative predictive value of coronary arterial calcification seen by multidetector CT are relatively high.     

Utility of arterial phase of dynamic CT for detection of intestinal ischemia associated with strangulation ileus

AIM:To clarify the usefulness of arterial phase scans in contrast computed tomography (CT) imaging of stran-gulation ileus in order to make an early diagnosis. METHODS:A comparative examination was carried out with respect to the CT value of the intestinal tract wall in each scanning phase, the CT value of the content in the intestinal tract, and the CT value of ascites fluid in the portal vein phase for a group in which ischemia was observed (Group Ⅰ) and a group in which ischemia was not observed (Group N) based on the pathological findings or intra-surgical findings. Moreover, a comparative examination was carried out in Group Ⅰ subjects for each scanning phase with respect to average differences in the CT values of the intestinal tract wall where ischemia was suspected and in the intestinal tract wall in non-ischemic areas. RESULTS:There were 15 subjects in Group Ⅰ and 30 subjects in Group N. The CT value of the intestinal tract wall was 41.8 ± 11.2 Hounsfield Unit (HU) in Group Ⅰ and 69.6 ± 18.4 HU in Group N in the arterial phase, with the CT value of the ischemic bowel wall being significantly lower in Group Ⅰ. In the portal vein phase, the CT value of the ischemic bowel wall was 60.6 ± 14.6 HU in Group Ⅰ and 80.7 ± 17.7 HU in Group N, with the CT value of the ischemic bowel wall being significantly lower in Group Ⅰ; however, no significant differences were observed in the equilibrium phase. The CT value of the solution in the intestine was 18.6 ± 9.5 HU in Group Ⅰ and 10.4 ± 5.1 HU in Group N, being signifi-cantly higher in Group Ⅰ. No significant differences were observed in the CT value of the accumulation of ascites fluid. The average difference in the CT values between the ischemic bowel wall and the non-ischemic bowel wall for each subject in Group Ⅰ was 33.7 ± 20.1 HU in the arterial phase, being significantly larger compared to the other two phases. CONCLUSION:This is a retrospective study using a small number of subjects; however, it suggests that there is a possibility that CT scanning in the arterial phase is useful for the early diagnosis of strangulation ileus.     

Dose and image quality of electron-beam CT compared with spiral CT.

RATIONALE AND OBJECTIVES: To examine dose and image quality of electron-beam CT (EBCT) with continuous volume scan versus spiral CT. METHODS: An EBCT scanner was compared with a spiral CT (SCT) scanner. Three phantoms were used to measure low-contrast resolution, high-contrast resolution, slice width, and dose. RESULTS: The EBCT scans showed 30% lower high-contrast resolution for most settings. The dose was comparable to that of spiral CT with 3 mm collimation and 76%/106% higher with EBCT for 1.5 mm/6 mm collimation. Low-contrast resolution was comparable to that of spiral CT using 3 mm collimation, slightly worse for 1.5 mm, and bad for 6 mm EBCT collimation (four times higher dose to reach comparable contrast-to-noise ratio). CONCLUSIONS: Significant restrictions were found using EBCT with continuous volume scan. The authors found that 3 mm collimation can yield acceptable high-contrast resolution and good low-contrast resolution compared with spiral CT. The use of 6 mm or 1.5 mm collimation needs to be restricted to selected cases.