动态容积CT在宫颈癌全器官灌注中可行性的初步研究

目的旨在探讨640层CT在宫颈癌全器官灌注中的应用价值以及正常宫颈组织和宫颈癌的CT灌注特征。方法对12例经病理证实的宫颈癌患者行320层CT灌注扫描。经肘静脉高压团注对比剂(7ml/s,350mg/ml),监测腹主动脉CT值自动触发行全子宫CT灌注扫描。用图像对位(Body registration)技术处理原始容积数据包,然后用体部灌注(Body Perfusion)软件进行图像和数据后处理。对正常宫颈组织和宫颈癌的CT灌注数据进行统计学分析。结果 12例宫颈癌患者全子宫完整显示,所有患者完成原始图像对位。宫颈癌的时间-密度曲线(TDC)均呈速升型。在灌注图上,宫颈癌显示清晰,与正常宫颈组织相比灌注明显增高,宫颈癌的血容量(AF)(255.42±28.14)ml/min/100ml明显高于正常宫颈组织的AF(168.34±7.49)ml/min/100ml(t值为3.189,P<0.05)。结论 640层CT的宫颈癌动态容积CT灌注具有良好的可操作性和可行性。CT灌注作为综合评价宫颈癌的一种影像学手段,可很好评价病灶的血流动力学改变,是常规CT扫描的有益补充。     

多排螺旋CT正常胰腺和胰腺癌灌注研究

目的:探讨正常胰腺和胰腺癌多排螺旋灌注成像特征。方法:30例无胰腺疾病的患者和16例经病理证实的胰腺癌患者,采用16层螺旋CT进行灌注扫描,分别测量30例正常胰腺组织和16例胰腺癌肿瘤组织的局部组织血流量(bloodflow,BF)、血容量(blood volume,BV)、毛细血管表面通透性(permeability surface area product,PS)和造影剂平均通过时间(meantransit time,MTT)平均值,并进行分析。结果:正常胰腺CT灌注成像特征表现为局部组织血流量(BF)、血容量(BV)、毛细血管表面通透性(PS)和造影剂平均通过时间(MTT)均匀一致的实质性器官;胰腺癌的BF、BV和PS均明显比正常胰腺的测量值降低。结论:CT灌注成像技术对胰腺癌诊断具有重要的提示意义。     

多排螺旋CT灌注成像对胰腺疾病的诊断价值

目的探讨64排螺旋CT灌注成像对正常胰腺、胰腺癌和慢性胰腺炎的灌注参数特征及诊断价值。资料与方法对正常者、胰腺癌及慢性胰腺炎者共45例进行腹部增强CT及胰腺灌注成像,得到灌注图像和时间密度曲线(TDC),测量正常组织及病灶区的血流量(BF)、血容量(BV)、平均通过时间(MTT)、表面渗透性值(PS)、灌注起始时间(TTS)、峰值(PE)及达峰时间(TTP),比较正常胰腺各部位间、正常组与病变组的非病变区之间以及病变区之间各灌注参数差异的统计学意义。结果正常组、胰腺癌组和慢性胰腺炎组的病变区,除TTS外各参数的差异均有统计学显著性(P<0.05)。正常胰腺头、体、尾间灌注参数的差异无统计学意义(P>0.05)。三组的非病变区各参数的差异无统计学意义。结论 64排螺旋CT胰腺灌注对胰腺癌及慢性胰腺炎的鉴别诊断有重要意义,能为临床诊断及治疗提供线索。     

Detectability of pancreas divisum in patients with acute pancreatitis on multi-detector row computed tomography

The purpose of this study was to retrospectively assess the diagnostic performance of multi-detector row computed tomography (MDCT) in an evaluation of pancreas divisum using endoscopic retrograde pancreatography (ERP) as the reference standard. We analyzed 41 consecutive patients (14 cases of pancreas divisum and 27 cases of standard anatomy) who had undergone both MDCT and ERP for the evaluation of clinically diagnosed acute pancreatitis between November 2004 and June 2007. The CT reconstruction thickness and interval were both 3 mm. Two radiologists independently reviewed CT data, and the diagnostic confidence in determining the pancreatic ductal anatomy was scored using a five-point scale. CT detectability was correlated with the severity of pancreatitis and the degree of pancreatic necrosis based on the Balthazar index. With consensus, 16 of 41 cases (39.0%) were evaluated as indeterminate. Ductal anatomy was correctly diagnosed in 23 of 41 cases (56.1%). Eight of 14 cases (57.1%) were correctly diagnosed as pancreas divisum. Standard anatomy was identified in 15 of 27 cases (55.6%). The inter-observer agreement was substantial (κ = 0.71). Grade B or more pancreatitis and the presence of pancreatic necrosis significantly influenced the evaluation of ductal anatomy (p = 0.01 and p < 0.01, respectively). Pancreas divisum was correctly diagnosed in the case of grade A acute pancreatitis. The CT detectability of pancreas divisum in patients with grade B or more pancreatitis is still relatively low even in the MDCT era.     

16层螺旋CT胰腺癌灌注研究

目的探讨正常胰腺和胰腺癌的MSCT灌注成像特征。方法30例无胰腺疾病的患者和16例经病理证实的胰腺癌患者,采用16层螺旋CT进行灌注扫描,分别测量30例正常胰腺组织和16例胰腺癌肿瘤组织及周围正常胰腺组织的血流量(BF)、血容量(BV)、平均通过时间(MTT)和表面通透性(PS)值,并进行分析。结果胰腺CT灌注的各项指标个体差异较大,但正常胰腺组织和癌周相对正常的胰腺组织的BF、BV、PS和MTT的平均值差异无显著性意义。正常胰腺组织和癌周相对正常胰腺组织的BV、BF高于胰腺癌组织,PS低于胰腺癌组织。胰腺癌周围相对正常胰腺组织与胰腺癌组织PS、BV和BF前后配对t检验差异更加明显。结论CT灌注成像技术对胰腺癌诊断具有重要的提示意义。     

CT灌注成像辅助诊断胰腺癌

目的:CT灌注是一种新的功能成像方法,它能反映组织内的血液灌注的变化。本文旨在研究胰腺癌的CT灌注特征及探讨64层螺旋CT胰腺灌注成像在胰腺癌辅助诊断中的价值。方法:临床拟诊胰腺癌的患者49例,采用64层螺旋CT行胰腺灌注扫描,灌注扫描结束后进行常规胰腺双期扫描。对灌注参数:局部组织血流量(blood flow,BF)、血容量(blood volume,BV)、峰值(PE)、渗透性(permeability,P)和达峰时间(time to peak,TTP)进行统计分析。结果:12例因为技术原因或非胰腺癌病例而排除在外。剩下的37例包括13例正常胰腺和病理证实的胰腺癌24例。正常胰腺实质与胰腺癌周围的正常胰腺组织在BF(146.23 vs.119.37),BV(194.51 vs.173.67),PE(85.08 Vs.72.47),TTP(126.48 Vs.135.07),Permeability(84.86 Vs.69.11)上无统计学差异(P>0.05).胰腺癌组织的BF(55.10 Vs.146.23),BV(89.19 Vs.194.51),and PE(42.97 vs.85.08)明显低于瘤周的正常胰腺组织,差异有显著性(P<0.05)。但是两者的TTP(131.73 Vs.126.48)and Permeability(59.94 Vs.84.86)无明显差异(P>0.05)。结论:64层螺旋CT胰腺癌的灌注研究显示肿瘤的BF,BV,and PE明显减低.CT灌注扫描对胰腺癌的诊断有一定价值。     

Initial experience with a chest pain protocol using 320-slice volume MDCT

We sought to determine the feasibility and image quality of 320-slice volume computed tomography (CT) angiography for the evaluation of patients with acute chest pain. Thirty consecutive patients (11 female, 19 male, mean age 63.2 ± 14.2 years) with noncritical, acute chest pain underwent 320-slice CT using a protocol consisting of a nonspiral, nongated CT of the entire chest, followed by a nonspiral, electrocardiography-gated CT study of the heart. Data were acquired following a biphasic intravenous injection of 90 ml iodinated contrast agent. Vessel attenuation values of different thoracic vascular territories were recorded, and image quality scored on a five-point scale by two readers. Mean attenuation was 467 ± 69 HU in the ascending aorta, 334 ± 52 HU in the aortic arch, 455 ± 71 HU in the descending aorta, 492 ± 94 HU in the pulmonary trunk, and 416 ± 63 HU and 436 ± 62 HU in the right and left coronary artery, respectively. Radiation exposure estimates ranged between 7 and 14 mSv. The CT protocol investigated enabled imaging of the thoracic aorta, coronary and pulmonary arteries with an excellent diagnostic quality for chest pain triage in all patients. This result was achieved with less contrast material and reduced radiation exposure compared with previously investigated imaging protocols.     

正常胰腺MSCT灌注成像与个体因素的相关性研究

目的:应用MSCT灌注成像技术,探讨正常胰腺CT灌注参数与年龄及体质指数(BMI)的相关性。方法:对符合正常胰腺纳入标准的35例患者按年龄及BMI分组,分别行16层螺旋CT胰腺灌注成像,三点测量各组胰腺的组织血流量(BF)、血容量(BV)、毛细血管表面通透性(PS)和对比剂平均通过时间(MTT)值,取各组灌注参数平均值,按组别进行统计学分析。结果:①年龄组:44岁(包括44岁)以下组,胰腺BF、BV、PS及MTT灌注值分别为(172.92±77.63)ml/(100g.min)、(61.63±24.37)ml/100g、(175.08±150.44)ml/(100g.min)、(34.74±13.74)s;45～59岁组,其灌注值分别为(181.61±133.36)ml/(100g.min)、(52.30±24.19)ml/100g、(213.44±151.20)ml/(100g.min)、(39.70±15.35)s;60岁(包括60岁)以上组,其灌注值分别为(118.99±37.89)ml/(100g.min)、(45.62±9.40)ml/100g、(202.72±91.08)ml/(100g.min)、(32.17±9.00)s。②BMI组:体质指数为22以下(包括22)组,胰腺BF、BV、PS及MTT灌注值分别为(154.39±79.88)ml/(100g.min)、(52.92±23.79)ml/100g、(209.85±147.52)ml/(100g.min)、(36.51±13.01)s;体质指数为22以上组,其灌注值分别为(182.82±120.96)ml/(100g.min)、(59.66±18.72)ml/100g、(157.68±107.50)ml/(100g.min)、(33.96±14.52)s。相关性分析结果显示,年龄与BF间呈负相关(P<0.05),余胰腺各灌注参数值与年龄及BMI均无相关性(P>0.05)。结论:胰腺的血流灌注,除血流量随年龄增长有逐步下降趋势外,其余受个体因素的影响小。     

急性主动脉夹层患者320排CT肾脏灌注研究

目的:研究主动脉夹层的患者肾脏的CT灌注特点,评价其指导手术的意义。方法:采用东芝公司AQUIL-ION ONE 320排CT,对30名诊断主动脉夹层的患者,术前进行双肾血流灌注检查,测量肾血流量参数值。根据肾动脉受累情况,分为真腔组、假腔组、夹层组、骑跨组。真腔组为肾动脉未受累,假腔组为肾动脉起自假腔,夹层组为肾动脉可见内膜片,骑跨组为肾动脉开口骑跨内膜破口。结果:30名患者,右肾动脉正常22例,受累8例,其中右肾动脉起自假腔6例,骑跨内膜破口2例;左肾动脉正常16例,受累14例,其中左肾动脉起自假腔9例,骑跨3例,夹层2例。真腔组、假腔组、夹层组、骑跨组肾皮质血流量参数平均值分别为305.2±7.7,311.2±11.7,126.2±11.6,364.5±12.0;肾髓质血流量参数平均值分别为175.9±7.8,173.2±12.1,89.7±15.3,231.3±8.0。采用t检验,真腔组与夹层组、骑跨组差异显著,P<0.05;与假腔组血流量参数值差异不显著,P>0.05;骑跨组肾血流量大于真腔组、假腔组,夹层组肾血流量小于真腔组、假腔组。结论:肾脏动态CT灌注不但可以观察肾动脉有无夹层或狭窄,还可以反映肾脏的微循环改变。研究主动脉夹层的患者肾脏的CT灌注特点,通过测量肾血流量以判定肾脏的功能,有助于术前的充分准备,指导术中、术后治疗方案,具有重要的临床意义。     

A comparison of tumour perfusion assessed by deconvolution-based analysis of dynamic contrast-enhanced CT and MR imaging in patients with squamous cell carcinoma of the upper aerodigestive tract

Our aim was to compare the perfusion [blood flow (BF)] values obtained by first-pass dynamic contrast-enhanced (DCE) T2-weighted magnetic resonance (MR) and computed tomography (CT) imaging of squamous cell carcinoma (SCC) in the upper aerodigestive tract in the same patient population. Seventeen patients with histologically proven primary SCC of the upper aerodigestive tract were prospectively evaluated. The perfusion CT studies were obtained using a 16-row multi-slice CT scanner running a commercial software package with a deconvolution-based technique; while the perfusion MR studies (1.5 T) were analysed with in-house-written MR perfusion software based also on a deconvolution technique. The mean perfusion values of SCC assessed by perfusion CT and MR imaging were 68.93 ± 31.61 and 81.56 ± 49.25 ml/min/100 g, respectively. The Bland-Altman graph showed a proportional error in the perfusion values measured by DCE-CT and -MR imaging; however, the degree of agreement was acceptable (95% limits of agreement: −66.1 to 40.8). Regression analysis of the perfusion values demonstrated significant correlation between the modalities: BF_MR = 1.34 × BF_CT – 10.93 (P < 0.0005, r ² = 0.74). The parametric maps generated by both modalities provided insights into the tumour perfusion, while analysis of the obtained perfusion values demonstrated that both modalities may be used interchangeably in SCC in the upper aerodigestive tract.     

Delineation of temporal bone anatomy: feasibility of low-dose 64-row CT in regard to image quality

The aim of our present study was to evaluate the visualization of anatomical landmarks of the temporal bone using a low-dose 64-slice computed tomography (CT) technique. A total of 120 patients were evaluated, 60 patients (mean age 47.1 years; 36 male, 24 female) underwent examination with a 4-slice CT scanner: 180 mAs, 120 kV, 1 s rotation time, 2 × 0.5 mm collimation, 0.5 mm slice thickness. Another 60 consecutive patients (mean age 37.4 years; 43 male, 37 female) were examined using a 64-slice CT low-dose protocol: 140 mAs, 120 kV, 1 s rotation time, 12 × 0.6 mm collimation, 0.6 mm slice thickness. The visibility of 42 landmarks was scored by two blinded radiologists using a five-point quality rating scale. Mean equivalent dose was significantly lower for the 64-slice CT protocol (0.31 mSv ± 0.12 mSv) compared to the 4-slice CT protocol (0.61 mSv ± 0.08 mSv). Despite increased image noise, only 19% of the anatomical landmarks were delineated significantly better on the axial sections of the 4-slice CT and only 9.5% of the anatomical landmarks on the reformatted coronal images. The interobserver agreement did not differ significantly between the two modalities. Low-dose 64-slice CT technique facilitates temporal bone imaging with sufficient anatomical detail.     

Validation of a new cardiac image fusion software for three-dimensional integration of myocardial perfusion SPECT and stand-alone 64-slice CT angiography

Purpose Combining the functional information of SPECT myocardial perfusion imaging (SPECT-MPI) and the morphological information of coronary CT angiography (CTA) may allow easier evaluation of the spatial relationship between coronary stenoses and perfusion defects. The aim of the present study was the validation of a novel software solution for three-dimensional (3D) image fusion of SPECT-MPI and CTA. Methods SPECT-MPI with adenosine stress/rest ^99mTc-tetrofosmin was fused with 64-slice CTA in 15 consecutive patients with a single perfusion defect and a single significant coronary artery stenosis (≥50% diameter stenosis). 3D fused SPECT/CT images were analysed by two independent observers with regard to superposition of the stenosed vessel onto the myocardial perfusion defect. Interobserver variability was assessed by recording the X, Y, Z coordinates for the origin of the stenosed coronary artery and the centre of the perfusion defect and measuring the distance between the two landmarks. Results SPECT-MPI revealed a fixed defect in seven patients, a reversible defect in five patients and a mixed defect in three patients and CTA documented a significant stenosis in the respective subtending coronary artery. 3D fused SPECT/CT images showed a match of coronary lesion and perfusion defect in each patient and the fusion process took less than 15 min. Interobserver variability was excellent for landmark detection (r = 1.00 and r = 0.99, p < 0.0001) and very good for the 3D distance between the two landmarks (r = 0.94, p < 0.001). Conclusion 3D SPECT/CT image fusion is feasible, reproducible and allows correct superposition of SPECT segments onto cardiac CT anatomy.     

320排容积CT低剂量灌注成像在慢性肾脏病肾功能评估中的应用

目的：探讨肾脏320排容积CT低剂量灌注成像在肾功能评估中的价值。方法10名双肾功能正常者按照CT扫描剂量分为低剂量组与常规剂量组;13例慢性肾脏病患者（均采用低剂量扫描）根据肾小球滤过率（GFR）分为肾小球功能轻度受损组和中重度受损组;利用320排容积CT灌注成像测定肾皮质血流量并比较各组肾皮质血流量差别。结果320排容积CT灌注扫描均成功。在肾功能正常组中,低剂量组与常规剂量组剂量长度乘积（DLP）分别为417．8 mGy·cm及833．6 mGy·cm,低剂量组射线剂量较常规剂量低约50％;常规剂量组及低剂量组肾皮质肾血流量（BF）分别为424±33 ml·100 g-1·min-1及416±30 ml·100 g-1·min-1,采用t检验,2组间肾皮质BF差异无统计学意义（t＝1．987,P＞0．05）。病例组中,肾功能轻度受损组与中重度受损组肾皮质BF分别为334±40 ml·100 g-1·min-1及236±44 ml·100 g-1·min-1,采用LSD检验两两比较,各病例组与对照组、2个病例组间肾皮质BF差异均有统计学意义（P＜0．05）。结论肾脏320排容积CT低剂量成像能降低辐射剂量,并对慢性肾脏病肾功能进行定量评估。     

轻症急性胰腺炎多层螺旋CT灌注成像

目的:探讨多层螺旋CT灌注成像技术在轻症急性胰腺炎(MAP)中的诊断价值。方法:30例无胰腺疾病的患者和23例临床上诊断为轻症急性胰腺炎、CT分级为A~B级的患者,采用16层螺旋CT进行灌注扫描。分别测量正常胰腺组织和MAP患者胰腺组织的血流量(BF)、血容量(BV)、平均通过时间(MTT)和表面通透性(PS)的平均值,并进行分析。结果:MAP相对于正常胰腺表现为较高的灌注,以A级MAP高灌注更为明显,而B级MAP由于水肿的存在,局部产生了等灌注或低灌注效应。结论:CT灌注成像技术对于MAP的诊断具有一定的提示意义,是一种可以在临床上广泛应用的新方法。     

Multi-organ perfusion CT in the abdomen using a 320-detector row CT scanner: preliminary results of perfusion changes in the liver, spleen, and pancreas of cirrhotic patients

Purpose

To utilize 320-detector row CT in perfusion CT of multiple abdominal organs and to compare the tissue perfusion between patients with and without liver cirrhosis.

Materials and methods

This study included 21 patients with cirrhosis and 20 without cirrhosis. The 320-detector row CT scanner enabled multi-organ perfusion CT without requiring the scanner table to be moved. Perfusion was calculated using the maximum slope model for the aorta, the portal vein, the right and left lobes of the liver, the head and body of the pancreas, the spleen, and the corpus and antrum of the stomach. Perfusion in each organ of patients with and without cirrhosis was compared.

Results

Portal venous perfusion of the right and left lobes of the liver in patients with cirrhosis (117 and 100 mL min⁻¹ 100 mL⁻¹, respectively) was significantly less than that in patients without cirrhosis (213 and 174 mL min⁻¹ 100 mL⁻¹, respectively; p = 0.0081 and 0.0294, respectively). Arterial perfusion of the spleen (111 mL min⁻¹ 100 mL⁻¹) and the body of the pancreas (112 mL min⁻¹ 100 mL⁻¹) in patients with cirrhosis was also significantly decreased compared with that in patients without cirrhosis (spleen, 162 mL min⁻¹ 100 mL⁻¹, p = 0.0020; body of pancreas, 133 mL min⁻¹ 100 mL⁻¹, p = 0.0405).

Conclusion

The results of the perfusion CT suggest that arterial perfusion of the spleen and the body of the pancreas, as well as portal perfusion of the liver, in cirrhotic patients was decreased compared with that in non-cirrhotic patients.     

CT findings of walled-off pancreatic necrosis (WOPN): differentiation from pseudocyst and prediction of outcome after endoscopic therapy

Computed tomography (CT) findings that may differentiate walled-off pancreatic necrosis (WOPN) from pancreatic pseudocyst were investigated. CT examinations performed before endoscopic therapy of pancreatic fluid collection (PFC) in 73 patients (45 WOPN, 28 pseudocysts) were evaluated retrospectively by two radiologists. PFC was evaluated for size, extension to paracolic space, characteristics of wall and internal structure. The pancreas was evaluated for deformity or discontinuity, and pancreatic duct dilation. CT findings that were associated with WOPN or pseudocyst were identified. CT score (number of CT findings associated with WOPN minus number of findings associated with pseudocyst) was calculated for each PFC. PFC was categorized as WOPN or pseudocyst using a CT score threshold. Larger size, extension to paracolic space, irregular wall definition, presence of fat attenuation debris in PFC, pancreatic deformity or discontinuity (P < 0.05–0.0001) were findings associated with WOPN. Presence of pancreatic duct dilation was associated with pseudocyst. Using a CT score of 2 or higher as a threshold, CT differentiated WOPN from pseudocyst with an accuracy of 79.5–83.6%. Thus, CT can differentiate WOPN from pseudocysts.     

Perfusion imaging of the pancreas using an arterial spin labeling technique

Purpose

To investigate the feasibility of perfusion imaging of the pancreas using an arterial spin labeling (ASL) technique.

Materials and Methods

An adapted flow‐sensitive alternating inversion recovery (FAIR)‐TrueFISP ASL technique was implemented on a 1.5T scanner. Anatomical and perfusion imaging in three different parts of the pancreas were performed in 10 healthy volunteers. Quantitative perfusion values were calculated using the extended Bloch equations.

Results

Perfusion images of all subjects showed diagnostic image quality in the pancreatic tail and the head. Assessment of pancreatic tissue perfusion was possible in all organ parts. Mean perfusion values were 271 ± 79 mL/100g/min in the head, 351 ± 112 mL/100g/min in the body, and 243 ± 55 mL/100g/min in the tail of the pancreas. Total examination time for perfusion imaging of the entire organ was 15.4 minutes.

Conclusion

FAIR‐TrueFISP permits analysis of pancreatic tissue perfusion with good image quality in a clinically applicable measuring time. Assessment of perfusion disorders may be useful in the diagnosis of inflammatory pancreatic pathologies, endocrine and exocrine pancreatic disorders, and in monitoring of pancreatic transplants. J. Magn. Reson. Imaging 2008;28:1459–1465. © 2008 Wiley‐Liss, Inc.     

Assessment of the spatial pattern of colorectal tumour perfusion estimated at perfusion CT using two-dimensional fractal analysis

The aim was to evaluate the feasibility of fractal analysis for assessing the spatial pattern of colorectal tumour perfusion at dynamic contrast-enhanced CT (perfusion CT). Twenty patients with colorectal adenocarcinoma underwent a 65-s perfusion CT study from which a perfusion parametric map was generated using validated commercial software. The tumour was identified by an experienced radiologist, segmented via thresholding and fractal analysis applied using in-house software: fractal dimension, abundance and lacunarity were assessed for the entire outlined tumour and for selected representative areas within the tumour of low and high perfusion. Comparison was made with ten patients with normal colons, processed in a similar manner, using two-way mixed analysis of variance with statistical significance at the 5% level. Fractal values were higher in cancer than normal colon (p ≤ 0.001): mean (SD) 1.71 (0.07) versus 1.61 (0.07) for fractal dimension and 7.82 (0.62) and 6.89 (0.47) for fractal abundance. Fractal values were lower in ‘high’ than ‘low’ perfusion areas. Lacunarity curves were shifted to the right for cancer compared with normal colon. In conclusion, colorectal cancer mapped by perfusion CT demonstrates fractal properties. Fractal analysis is feasible, potentially providing a quantitative measure of the spatial pattern of tumour perfusion.     

Dual-energy perfusion-CT of pancreatic adenocarcinoma

Purpose

To evaluate the feasibility of dual-energy CT (DECT)-perfusion of pancreatic carcinomas for assessing the differences in perfusion, permeability and blood volume of healthy pancreatic tissue and histopathologically confirmed solid pancreatic carcinoma.

Materials and methods

24 patients with histologically proven pancreatic carcinoma were examined prospectively with a 64-slice dual source CT using a dynamic sequence of 34 dual-energy (DE) acquisitions every 1.5 s (80 ml of iodinated contrast material, 370 mg/ml, flow rate 5 ml/s). 80 kV_p, 140 kV_p, and weighted average (linearly blended M0.3) 120 kV_p-equivalent dual-energy perfusion image data sets were evaluated with a body-perfusion CT tool (Body-PCT, Siemens Medical Solutions, Erlangen, Germany) for estimating perfusion, permeability, and blood volume values. Color-coded parameter maps were generated.

Results

In all 24 patients dual-energy CT-perfusion was. All carcinomas could be identified in the color-coded perfusion maps. Calculated perfusion, permeability and blood volume values were significantly lower in pancreatic carcinomas compared to healthy pancreatic tissue. Weighted average 120 kV_p-equivalent perfusion-, permeability- and blood volume-values determined from DE image data were 0.27 ± 0.04 min⁻¹ vs. 0.91 ± 0.04 min⁻¹ (p < 0.0001), 0.5 ± 0.07 *0.5 min⁻¹ vs. 0.67 ± 0.05 *0.5 min⁻¹ (p = 0.06) and 0.49 ± 0.07 min⁻¹ vs. 1.28 ± 0.11 min⁻¹ (p < 0.0001). Compared with 80 and 140 kV_p the standard deviations of the kV_p120 kV_p-equivalent values were manifestly smaller.

Conclusion

Dual-energy CT-perfusion of the pancreas is feasible. The use of DECT improves the accuracy of CT-perfusion of the pancreas by fully exploiting the advantages of enhanced iodine contrast at 80 kV_p in combination with the noise reduction at 140 kV_p. Therefore using dual-energy perfusion data could improve the delineation of pancreatic carcinomas.     

双低剂量320排 CT 全脑灌注技术在急性期脑缺血中的应用价值

目的：探讨采用“双低剂量”320排 CT 全脑灌注成像联合 CTA 在急性脑缺血中的可行性及实用价值。方法采用“双低方案”对40例拟诊为急性脑缺血患者行320排 CT 全脑灌注成像联合 CTA 一站式检查。利用软件包处理得到 CTA、4D-CTA、4D-perfusion、Fusion 图像,40例患者均经3.0T MR 行 DWI 作为对照。分析评价 CTA 图像质量、血管狭窄程度及缺血病变位置。结果有脑动脉狭窄或闭塞的患者33例,其中8例经 DSA 证实。CTA 质量达优率为82.5%。CT 灌注成像(CTP)发现297处灌注异常区,其中202处病灶 DWI 证实为脑梗死区,95处 DWI 未见异常：49处 CTP 表现为延迟时间(DLY)、达峰时间(TTP)升高,脑血流量(CBF)、脑血容量(CBV)轻度降低;21处 DLY、TTP 升高,CBF、CBV 正常;25处 DLY、TTP 升高,CBF、CBV 轻度升高。结论“双低剂量”320排 CT 脑灌注联合 CTA 是具有可行性和实用性的,可以准确观察颅内血管形态结构及脑组织梗死前期缺血的状态。