双能量CT肺灌注成像评价急性肺栓塞严重程度的可行性研究

目的分析双源CT双能量肺灌注成像(DEPI)技术评价急性肺动脉栓塞(APE)严重程度的可行性。方法经双源CT诊断APE24例,采用Lung PBV软件进行数据处理,得到CT肺血管图像(CTPA)和DEPI,分别计算每位患者的灌注缺损指数、栓塞指数及双室短轴最大径比(RV/LV),依据患者严重程度分为严重APE组(n=9)和非严重APE组(n=15),比较两组灌注缺损指数、栓塞指数及RV/LV,并进行Spearman等级相关分析。结果严重APE组的灌注缺损指数、栓塞指数及RV/LV中位数分别为32.5%(15.0%~62.5%)、45.0%(27.5%~75.0%)和1.16(1.04~1.45),而非严重APE组分别为12.5%(0%~37.5%)、12.5%(2.5%~42.5%)和1.03(0.85~1.41),严重APE组的各项指标均高于非严重组,两组间差异有统计学意义(P<0.05)。相关分析显示,灌注缺损指数与RV/LV及栓塞指数均呈正相关(分别为r=0.635,P<0.05;r=0.790,P<0.05)。结论采用双源CT双能量肺灌注成像技术评价APE严重程度具有一定可行性。     

鼻咽癌放疗后放射性脑病的CT灌注研究

目的：应用CT灌注成像观察放射性脑病微循环血流动力学变化及其病理基础，进一步推测放射性脑病的可能发病机制。方法：病理证实鼻咽癌20例共26个病灶，选17个病灶对侧颞叶非病变区共22个感兴趣区（ROI），与颞叶病变区ROI灌注结果进行比较。结果：CT灌注图像中显示26个低脑血流量（CBF）、低脑血液容积（CBV）病灶，同时也显示峰值时间（TP）图中对比剂到达延迟。其中23个颞叶病变中，7个颞叶坏 死灶内未见血流灌注。16个颞叶非坏死病变与22个非病变区颞叶白质比较，非坏死病变区CBF下降，平均通过时间（MTT）延长，其差异均具有非常显著性意义（t值分别为7．47，9．38；P值均＜0．01）。TP延长不显著（t＝1．78，P＞0．05）。3个桥脑放射性脑病的CBF均较正常值均值降低。结论：CBF是反映放射性脑病微循环灌注的直接指标，其诊断意义较大。MTT、TP是反映血管阻力的参数，有诊断有参考价值。病灶区的微循环障碍是其重要的病理基础，其CBF下降，提示微循环障碍，更进一步支持了放射性脑病的血管 损伤学说。     

正常前列腺MSCT灌注成像的临床研究

目的：探讨正常前列腺CT灌注成像的表现。方法：33例正常前列腺经肘静脉注射对比剂后,对选定的前列腺组织层面行MSCT定层连续扫描40次,将得到的160帧图像输入Functional CT软件内,根据同层参考动脉和前列腺组织的时间-密度曲线和各组织强化值计算各层面内每一像素的灌注指标,包括灌注值、TTP、PEI、BV。结果：正常前列腺组织中央带的灌注值、强化峰值（PEI）、达峰时间（TTP）及血容量（BV）分别为（20.93±6.57）ml/（min·mg）、（24.68±5.04）HU、（26.23±2.97）s、（345.62±93.38）ml/g;外周带的分别为（15.65±4.99）ml/（min·mg）、（18.17±4.01）HU、（25.43±2.64）s、（233.61±66.67）ml/g。中央带与外周带的TDC曲线为平坦型,未见明显上升支。双侧外周带TDC曲线对称,基本重合。结论：正常前列腺组织属于低血供器官,中央带的血流灌注值高于外周带,双侧外周带的血流灌注基本对称。     

Feasibility of FAIR imaging for evaluating tumor perfusion

Purpose:

To evaluate the feasibility of flow‐sensitive alternating inversion recovery (FAIR) for measuring blood flow in tumor models.

Materials and Methods:

In eight mice tumor models, FAIR and dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) was performed. The reliability for measuring blood flow on FAIR was evaluated using the coefficient of variation of blood flow on psoas muscle. Three regions of interest (ROIs) were drawn in the peripheral, intermediate, and central portions within each tumor. The location of ROI was the same on FAIR and DCE‐MR images. The correlation between the blood flow on FAIR and perfusion‐related parameters on DCE‐MRI was evaluated using the Pearson correlation coefficient.

Results:

The coefficient of variation for measuring blood flow was 9.8%. Blood flow on FAIR showed a strong correlation with Kep (r = 0.77), percent relative enhancement (r = 0.73), and percent enhancement ratio (r = 0.81). The mean values of blood flow (mL/100 g/min) (358 vs. 207), Kep (sec^?1) (7.46 vs. 1.31), percent relative enhancement (179% vs. 134%), and percent enhancement ratio (42% vs. 26%) were greater in the peripheral portion than in the central portion (P < 0.01).

Conclusion:

As blood flow measurement on FAIR is reliable and closely related with that on DCE‐MR, FAIR is feasible for measuring tumor blood flow. J. Magn. Reson. Imaging 2010;32:738–744. © 2010 Wiley‐Liss, Inc.

     

双源CT灌注成像在肾细胞癌及肾盂癌诊断中的应用研究

目的分析双源CT(DSCT)肾细胞癌、肾盂癌灌注参数的特点,探讨灌注成像对肾细胞癌及肾盂癌诊断的应用价值。方法回顾性分析经手术病理证实的34例肾细胞癌、15例肾盂癌,行西门子Somatom Sensation 64螺旋CT灌注扫描,应用西门子工作站分别测量肿瘤及对照组正常肾皮质的灌注参数:血流(BF)、血容量(BV)、开始时间(TTS)、达峰时间(TTP)、Patlak血管通透性(PS)、Patlak血容量(PBV)。结果①肾细胞癌BF、BV、PS、PBV低于对侧正常肾皮质(对照组),而TTP则高于对照组肾皮质,二者之间差异有统计学意义(P<0.05);肾细胞癌TTS高于对照组肾皮质,二者之间差异无统计学意义(P>0.05);②肾盂癌BF、BV、PS、PBV低于对侧正常肾皮质(对照组),二者之间差异有统计学意义(P<0.05);肾盂癌TTS高于对照组肾皮质,而TTP则低于对照组肾皮质,二者之间差异无统计学意义(P>0.05);③肾细胞癌BF、BV、PBV高于肾盂癌,二者之间差异有统计学意义(P<0.05);肾细胞癌TTS低于肾盂癌,而TTP、PS则高于肾盂癌,二者之间差异无统计学意义(P>0.05)。结论肾细胞癌、肾盂癌及正常肾皮质DSCT灌注参数不同。DSCT灌注成像在肾脏DSCT灌注成像在肾细胞癌及肾盂癌诊断和鉴别诊断方面有一定的应用价值。     

肝细胞癌CT灌注成像的诊断和临床应用

近年来,随着CT硬件与软件技术的发展,CT灌注成像在肝脏疾病诊断中取得了较大进步。本文就其基本原理、成像技术、诊断、临床应用等作一综述,重点在于CT灌注成像对肝细胞癌治疗的疗效评估及监测具有指导意义。     

CT灌注成像在肾细胞癌中的应用进展

肾细胞癌(RCC)是泌尿系统常见的恶性肿瘤,其发病率及死亡率近年来逐渐上升。影像检查对RCC的定性诊断、分级与治疗反应评价具有重要价值。CT灌注成像(CTPI)是一种功能成像技术,能无创性反映整个肿瘤的微循环血流灌注情况,RCC的CTPI评估成为研究热点。CTPI灌注参数不仅有助于判断RCC部分亚型,还可以与肾盂癌及乏脂肪肾血管平滑肌脂肪瘤进行鉴别,并且能够预测RCC病理分级、评估非切除治疗及RCC转移灶的疗效,以及判断预后。就CTPI对RCC以上几方面的研究现状及进展予以综述。     

舌癌多层螺旋CT灌注成像的初步研究

舌癌是口腔颌面部最常见的恶性肿瘤之一,CT、MRI已经成为舌癌术前常规检查方法,但舌癌的CT灌注研究国内外文献报道少见,本研究旨在探讨舌癌MSCT灌注成像的可行性,研究舌癌的MSCT灌注特征,结果报告如下.     

Whole tumour perfusion of peripheral lung carcinoma: evaluation with first-pass CT perfusion imaging at 64-detector row CT

AIM: To prospectively assess the feasibility of a whole-tumour perfusion technique using 64-detector row computed tomography (CT) and to analyse the variation of CT perfusion parameters in different histological types, sizes, and metastases in patients with peripheral lung carcinoma. METHODS AND MATERIALS: Ninety-seven pathologically proved peripheral lung carcinomas (less than 5 cm in largest diameter) underwent dynamic contrast-enhanced CT using a 64-detector row CT machine. Small amounts of iodinated contrast medium with a sharp bolus profile (50 ml, 6-7 ml/s), and 12 repeated fast acquisitions encompassing the entire tumour lesion were adopted to quantify perfusion of the whole-tumour during first-pass of contrast medium. Four kinetic parameters, including perfusion, peak enhancement intensity (PEI), time to peak (TTP), and blood volume (BV), were measured and statistically compared among different histological types, sizes, and metastases. RESULTS: Mean values for perfusion, PEI, TTP, and BV of the 97 lung carcinomas were 57.5+/-45.4 ml/min/ml (range 5.9-243 ml/min/ml), 53.4+/-40.6 HU (range 10.3-234.4 HU), 34+/-11s (range 11-60s), and 30.1+/-21.7 ml/100g (range 3.9-113.4 ml/100g), respectively. No statistical differences were found between the histological types regarding the perfusion parameters (p>0.05). Perfusion, PEI, and BV of stage T2 tumours were significantly lower than those of stage T1 tumours (all p < 0.05), whereas no statistically significant differences was found between other stages of tumours (all p>0.05). Perfusion of the tumours with distant metastasis was significantly higher than that of the tumours without distant metastasis (p<0.05), but there was no statistically significant difference between nodal metastasis positive and negative groups (p>0.05). CONCLUSION: The present study of first-pass perfusion imaging using 64-detector row CT could provide a feasible method for assessment of whole-tumour perfusion. CT perfusion parameters of peripheral lung carcinoma may be associated with tumour size and distant metastasis.     

急性脑静脉闭塞CT灌注成像的实验研究

目的观察脑静脉闭塞模型脑实质损害区CT灌注成像（CTP）变化规律,探讨该模型在该病研究中的价值。方法新西兰大白兔28只,随机分为2组（实验组24只,对照组4只）。一侧颈内静脉注入醋酸纤维素聚合物（CAP）合并双侧颈外静脉结扎术后1、3、6、12、24和48h行CTP检查对各组模型的脑血流动力学改变进行观察。结果实验组21只造模成功,其中3h及12h组各有1只在CTP上无明显异常表现,有19只CTP检查示脑血流灌注异常。术后1～3h,病变区脑血容量（CBV）轻度增加或正常,脑血流量（CBF）轻度降低,平均通过时间（MTT）稍延长;6～12h后病变中心区主要表现为CBV和CBF降低,MTT延长,而病变边缘区CBV增加或正常或轻度降低,CBF降低,MTT缩短;12～24h后病变中心区和边缘区CBV和CBF均明显降低,MTT明显延长。各时段病变中心区和边缘区的CBV%、CBF%、MTT%的差异均有统计学意义（P值均〈0.05）。对照组未见上述各种异常表现。结论 CT灌注成像可准确、敏感地反映急性脑静脉闭塞模型的血流动力学改变。     

Dynamic CT myocardial perfusion imaging

Cardiac CT offers several approaches to establish the hemodynamic severity of coronary artery obstructions. Dynamic myocardial perfusion CT (MPI_CT) is based on serial CT imaging to measure the inflow of contrast medium into the myocardium and calculate absolute measures of myocardial perfusion. This review describes the MPI_CT acquisition protocol, post-image acquisition processing and calculation of quantitative parameters, the diagnostic performance of MPI_CT and the potential incremental value of this technique in comparison to alternative approaches. Further technical innovation using different scanner platforms and establishment of reproducible diagnostic thresholds to differentiate significant coronary artery disease will be crucial in the path to broader clinical implementation.     

Evaluation of angiogenesis in colorectal carcinoma with multidetector-row CT multislice perfusion imaging

To evaluate the correlation between 64 multidetector-row CT (64MDCT) perfusion imaging in colorectal carcinoma and microvessel density (MVD) and vascular endothelial growth factor (VEGF), 64MDCT perfusion imaging was performed in 33 patients with pathologically verified colorectal carcinoma. These images were analyzed with perfusion functional software, and time-density curves (TDC) were created for the region of interest (ROI) encompassing the tumor, the target artery and vein. The individual perfusion maps generated indicated blood flow (BF), blood volume (BV), mean transit time (MTT), and permeability-surface area product (PS). MVD and VEGF were evaluated by immunohistochemical staining with anti-CD34 and anti-VEGF, respectively. Correlations between MVD or VEGF with CT perfusion parameters and clinicopathological factors (Dukes’ stages, invasion depth, and lymph node and liver metastasis) were also investigated. MVD in the colorectal carcinoma was 22.61 ± 9.01 per ×200 field. The scores obtained for VEGF expression were 4.15 ± 1.09. VEGF staining was positive in 25 of 29 tumors (86.2%). There was no significant correlation between the presence of MVD, VEGF expression and clinicopathological factors (P > 0.05). There was also no correlation between MVD, VEGF expression, and any dynamic CT parameters (P > 0.05). The BV and MTT were significantly higher in tumors demonstrating serous coat invasion than in those without it (t = −2.63, −2.24, P = 0.0137, 0.0331, respectively). BV was also significantly correlated with tumor size (r = 0.41, P = 0.02). Neither BF nor PS was correlated with clinicopathological factors. In conclusion, 64MDCT perfusion imaging, MVD, and VEGF may reflect angiogenic activity, but no significant correlation among these factors.     

结直肠癌微血管密度与螺旋CT灌注成像的相关性

目的探讨结直肠癌微血管密度与螺旋CT(SCT)灌注成像的相关性。方法经手术和病理证实的结直肠癌患者37例,水灌肠后行SCT扫描。先行结直肠肿块范围的平扫,选定靶平面后再进行同层动态增强扫描,采用東芝Xpress/SX螺旋CT机自带的灌注功能软件,绘制所选层面的癌灶、靶动脉的感兴趣区的时间密度曲线(TDC)。根据TDC计算病灶的血流灌注量(PF)。癌组织切片经鼠抗人CD34单克隆抗体进行免疫组织化学染色,测定癌组织微血管密度(MVD),将结直肠癌的MVD与血流灌注量进行比较。结果结直肠癌MVD为[87.28±41.18(33.11～173.44)]条/高倍视野,PF为[39.74±10.82(15.60～64.80)]ml·min-1·100g-1。MVD、PF在Dukes分期、浆膜浸润、淋巴结转移比较中差异均无统计学意义(P值均>0.05);MVD、PF随着病理分期的期别升高均有下降趋势,但两者无显著相关性(r=0.18,P>0.05)。结论结直肠癌的MVD与其血流灌注量之间无明显相关性,结直肠癌早期存在高度血管化和高的血流灌注量,SCT灌注成像可能较MVD更好地反映肿瘤的微循环功能。     

Early prediction of response of sorafenib on hepatocellular carcinoma by CT perfusion imaging: an animal study

Objective:

This study evaluated the feasibility of CT perfusion parameters for the early efficacy prediction of sorafenib in the treatment of hepatocellular carcinoma (HCC) in rats.

Methods:

CT hepatic perfusion measurements were performed in the livers of 40 rats implanted with rat HCC. The rats in the experimental group (n = 28) were treated by oral gavage with sorafenib (20 mg per day), whereas the rats in the control group (n = 12) were treated by normal saline. Rats were classified into the responder group if the maximum diameter of their tumour had decreased 21 days after treatment, whereas the other rats were classified into the non-responder group. Data were analysed using the Pearson correlation analysis or analysis of variance.

Results:

CT perfusion was used to depict haemodynamic changes before and after treatment. The arterial liver perfusion was significantly decreased in the responder group on Day 11 after treatment with sorafenib (from 71.5 to 53.4 ml min⁻¹ 100 ml⁻¹), whereas no significant changes were observed in the non-responder group (p = 0.87). The maximum diameter of the tumour was also significantly decreased in the responder group on Day 21 after treatment (p = 0.042), whereas the maximum tumour diameter was significantly increased in the control group (p = 0.001).

Conclusion and advances in knowledge:

CT perfusion could be used to quantitatively analyse the haemodynamic changes in the treatment of HCC with sorafenib, which indicates that this approach may be developed for the early prediction of treatment efficacy for sorafenib.Hepatocellular carcinoma (HCC) is ranked as the fifth most common cancer worldwide and the third most common cause of cancer-related deaths.¹ In the past few years, with increasing knowledge of molecular regulatory mechanisms of cancer progression, targeted antineoplastic drugs have been rapidly developed. Sorafenib, a molecular inhibitor of multiple protein kinases,² is the first approved molecular targeted drug for the treatment of HCC. It has been demonstrated that sorafenib can prolong the survival of patients with advanced HCC.³ Although sorafenib has been proven effective in the treatment of HCC, some patients develop adverse reactions or show no treatment effects, and, in some extreme cases, sorafenib has been shown to shorten survival in patients.⁴ If imaging techniques could be used to predict the therapeutic efficacy of sorafenib during the early stage of treatment, unnecessary treatment could be avoided, which would undoubtedly have a significant effect on reducing the physiological distress and financial burden of patients.The New Response Evaluation Criteria in Solid Tumors⁵ are currently the primary criteria for evaluating therapeutic efficacy in solid tumours. The evaluation criteria for tumour progression or remission measure the changes in the maximum diameter of a tumour, although this measure is not reliable in clinical practice. For example, tumour necrosis occurs within the mass after treatment, but tumour size is not simultaneously reduced. Under these circumstances, false-positive results may occur in the imaging evaluation, which would hide the true therapeutic efficacy. Perfusion imaging techniques are based on dynamic contrast-enhanced CT scans that can detect the haemodynamic status and functional changes in organs and tissues earlier than the morphological changes; as a result, these techniques can be used for the early detection and diagnosis of tumours.^6–8 This study sought to investigate whether CT perfusion imaging could be used to depict the effects of sorafenib on the inhibition of tumour angiogenesis in the treatment of HCC using a rat model.     

64层CT灌注成像在食管癌诊断方面的应用探讨

目的：探讨64层CT灌注成像图像后处理时的兴趣区选取方法对食管癌灌注参数测量的影响.方法：经病理证实的食管癌初发患者21例,包括鳞癌15例、腺癌4例和小细胞癌2例,均行CT灌注成像,利用perfusion 3.0软件包进行后处理,分别取兴趣区（ROI）面积为5、10、15和20 mm2,测量灌注参数,包括血容量（BV）、血流量（包BF）、平均通过时间（MTT）及表面通透性（PS）,比较不同ROI所测得的各项灌注参数是否有统计学差异.结果：ROI面积为5、10、15和20 mm2时BF均值分别为58.4、64.0、63.8和60.4 ml/（min·100g）,BV均值分别为4.3、4.5、4.5和4.5 ml/100g,MTT均值分别为6.9、6.6、7.0和7.4 s,PS均值分别为11.6,11.4、12.9和13.2 ml/（min·100g）,经过F检验及组内t检验,P〉0.2,4组数据间差异无显著性意义.结论：ROI大小的选择不会造成食管癌各灌注参数测量值的差异,所测得的各项参数值能够反映食管癌的微循环特征.     

Feasibility of dynamic myocardial CT perfusion using single-source 64-row CT

BackgroundDynamic myocardial computed tomography perfusion (CTP) is an emerging technique to diagnose significant coronary stenosis. However, this procedure has not been reported using single-source 64-row CT.ObjectiveTo investigate the radiation dose and the diagnostic performance of dynamic CTP to diagnose significant stenosis by catheter exam.MethodsWe prospectively included 165 patients who underwent CTP exam under adenosine stress using a single-source 64-row CT. MBF was calculated using the deconvolution technique. Quantitative perfusion ratio (QPR) was defined as the myocardial blood flow (MBF) of the myocardium with coronary stenosis divided by the MBF of the myocardium without significant stenosis or infarct. Of the 44 patients who underwent subsequent coronary angiography, we assessed the diagnostic performance to diagnose ≥50% stenosis by quantitative coronary analysis (QCA).ResultsThe average effective dose of dynamic CTP and the entire scans were 2.5 ± 0.7 and 7.3 ± 1.8 mSv, respectively. The MBF of the myocardium without significant stenosis was 1.20 ± 0.32 ml/min/g, which significantly decreased to 0.98 ± 0.24 ml/min/g (p < 0.01) in the area with ≥50% stenosis by CT angiography. The QPR of the myocardium with QCA ≥50% stenosis was significantly lower than 1 (0.84 ± 0.32, 95% confidence interval (CI), 0.77–0.90, p < 0.001). The accuracy to detect QCA ≥50% stenosis was 82% (95%CI, 74–88%) using CT angiography alone and significantly increased to 87% (95%CI, 80–92%, p < 0.05) including QPR.ConclusionDynamic myocardial CTP could be performed using 64-row CT with a low radiation dose and would improve the diagnostic performance to detect QCA ≥50% stenosis than CT angiography alone.     

双源CT双能量肺灌注成像的初步观察

目的 评价双源CT双能量扫描肺灌注成像的临床应用价值.方法 选择2007年5月至8月临床怀疑肺部疾病的连续54例患者行肺部增强双能量扫描,按照肺部不同病变分为4组:正常组、渗出性病变组、肿块性病变组和肺栓塞组.分析不同组别之间双能量CT灌注成像的表现.结果 正常组14例,肺部双能量灌注成像表现双侧肺部灌注对称,未见明显差异.渗出性病变组10例,表现为局部灌注量降低;肿块性病变组27例,因为发生位置不同肺部灌注成像表现各异,外周性肿块表现为局部肿块区域的灌注缺损,而中央型肿块因为累及肺门血管而表现为肺段性灌注降低区或缺损区.肺栓塞组3例,表现为肺栓塞区域的灌注缺损或稀疏.结论 利用双源CT双能量扫描可以观察肺的灌注状态,尤其有利于评价中央型肺癌和肺栓塞患者肺灌注的异常.     

Diagnostic value of CT perfusion imaging for parotid neoplasms

Objectives:

To assess the value of CT perfusion imaging in the differentiation of different histological categorization of benign tumours from malignant tumours in patients with parotid neoplasms.

Methods:

CT perfusion was successfully performed in 62 patients with parotid neoplasms whose diagnoses were confirmed by surgery or biopsy. The software generated a tissue time–density curve (TDC) and measured blood volume, blood flow, mean transit time and capillary permeability surface product. One-way ANOVA and receiver operating characteristic curves were used to analyse the difference and diagnostic efficacies of all perfusion data between each one of the benign tumours and malignancies. Statistical significance was assigned at the 5% level.

Results:

Pleomorphic adenomas mainly had a gradually ascending TDC. Warthin tumours showed a fast ascent followed by a fast descent. The TDC of basal cell adenomas had a fast ascension followed by a plateau, then a gradual descent. Malignant tumours mainly showed a rapidly ascending curve with a stable plateau. Significant differences were observed in blood flow, blood volume and mean transit time between pleomorphic adenomas and malignant tumours (p < 0.05) as well as in blood flow and blood volume between the Warthin tumours, the basal cell adenomas and the malignant tumours (p < 0.05). Differences in permeability surface between the basal cell adenomas and malignant tumours were significant (p < 0.01).

Conclusion:

CT perfusion of parotid gland could provide TDC and perfusion data, which were useful in the differentiation of different histological benign tumours and malignant tumours in the parotid gland.     

128层4D CT全肝灌注成像在肝细胞癌中的初步应用

目的:探讨128层4D CT全肝灌注成像在原发性肝癌(HCC)灌注中的参数特征及其初步临床应用价值。方法:对20例正常对照组、40例经临床或手术病理证实为HCC的患者行128层4D CT灌注扫描,获得灌注参数血流量(BF)、肝动脉灌注量(ALP)、门静脉灌注量(PVP)、肝动脉灌注指数(HAPI)。根据各灌注图像及相关参数评价正常组织与恶性肿瘤、高分化HCC与低分化HCC的血流动力学状态。同时获得270mm扫描覆盖范围内动态4D CTA图像,动态观察对比剂流入及流出情况,判断肿瘤供血动脉的增粗、僵直、门静脉癌栓等。结果:①HCC患者ALP、HAPI、BF明显高于正常组(P<0.01),PVP明显降低(P<0.01)。②高分化HCC患者灌注参数ALP、HAPI低于低分化HCC,PVP明显升高,二者差异有统计学意义(P<0.01)。灌注参数从一方面反映了肿瘤的恶性程度。③40例HCC中,4D CTA显示肿瘤供血动脉25例,13例供血动脉增粗、僵直,门静脉癌栓15例。结论:128层4D CT灌注成像可以通过一次注射对比剂,获得全肝灌注信息及动态的4DCTA,肝灌注模式成像克服了以往灌注成像的不足,简单实用,具有一定的优势。此技术能很好地反映HCC的血流动力学变化,为HCC的早期诊断、指导临床治疗及判断预后提供可靠的依据,具有重要的临床应用价值和广阔的应用前景。     

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.