Hepatic CT enhancement: effect of the rate and volume of contrast medium injection in an animal model

Background: To evaluate the relative effect of rate of injection and volume of contrast medium on aortic, portal, and hepatic enhancement during computed tomography (CT). Methods: Thirty-eight nonincremental CT examinations were performed in three mini-pigs by using a combination of three different volumes (1.5, 2, and 3 mL/kg) and five different rates (1.5, 3, 4.5, 6, and 7.5 mL/s) of contrast material injection. Time-density enhancement curves of the aorta, portal vein, and liver were plotted over time for each rate of injection, each volume of contrast, and each volume–rate combination. In addition, aortic, portal, and liver peak enhancements, time-to-peak enhancements, optimal scanning intervals, and contrast enhancement indices were calculated for each volume–rate combination. Results: Higher rates of injection increased peak aortic enhancement but had no effect on peak portal or hepatic enhancement. This result may be explained by the dilution of the bolus of contrast medium in the splanchnic circulation. When the results of a 6-mL/s injection of 1.5 mL/kg of contrast material were compared with a 3-mL/s injection of 2 mL/kg, maximum aortic enhancement increased by 32%, whereas maximum liver enhancement decreased by 35%. Conclusion: An increase in the rate of contrast injection results in an increase of peak aortic enhancement even when the total iodine load is decreased. However, an increase of the rate of contrast injection does not increase maximum liver enhancement, which is related to the total iodine dose injected. Therefore, one cannot compensate a decrease in the iodine load by an increase in injection rate in contrast-enhanced CT of the liver. Received: 3 September 1997/Revision accepted: 13 January 1999     

Coronary 64-slice computed tomographic angiography models employing aortic root and selective catheter directed contrast enhancement in swine: technical feasibility and preliminary results using 3D and 4D reconstructions

Purpose The technical feasibility of combining catheter directed coronary enhancement and multidetector computed tomographic angiography (MD-CTA) is presented in a swine model at various cardiac and injection rates.Materials/methods A 64-slice CT scanner was used under animal IRB approval in four sedated swine. Common femoral venous/arterial access with a 5 Fr micropuncture kit was ultrasound guided. Investigational 5 Fr diffusion-tip pigtail [aortic root (AR)-MD-CTA] and conventional 5 Fr coronary [selective (S)-MD-CTA] catheters were positioned on the CT table with c-arm fluoroscopy. AR-MD-CTA commenced 1–2 s after injection of 50 cc Visipaque mixed with 50 cc NS at 6 cc/s (n=3), 8 cc/s (n=5) or 10 cc/s (n=7) (HR=120, 100, 90, 80 or 65 bpm). S-MD-CTA (right and left, n=4) (HR= 90, 80, or 65 bpm) commenced 1–2 s after injection of 5 cc Visipaque mixed with 5 cc NS (1 cc/s). IV-MD-CTA (n=4) (HR=80 bpm) commenced 5 or 10 s after aortic peak density with 100 cc Visipaque (5 cc/s) and 50 or 75 cc NS (5 cc/s) flush. Conventional angiography (n=2) used standard protocol. MD-CTA was performed with the following parameters: collimation 0.6 mm, tube rotation time 0.3 s, table feed/rotation 3.8 mm, scan time 10–12 s, tube voltage 120 kVp, effective mAs 850, pitch 0.2, FOV 109–123 mm, slice thickness/increment 0.6 mm/0.3 mm, kernel B25 f smooth. Ex vivo imaging (64-slice CT, n=3) was also performed. Post-processing consisted of coronary peak densities, 3D-MIP’s and 4D projections.Results Catheter directed MD-CTA was feasible at all injection rates at and below 100 bpm and yielded higher peak coronary attenuation values than IV-enhanced studies. Definition and clarity of the tributary and distal anatomy was also higher than IV-enhanced CTA.Conclusions Catheter directed MD-CTA can be performed by retrofitting the current CT scanner with a portable c-arm fluoroscopy unit. S and AR MD-CTA provide high coronary anatomy definition and luminal attenuation without obscuring cardiac chamber signal and with the least iodinated contrast volume.     

多层螺旋CT肝脏血管成像最佳扫描时间的研究

目的对比传统方法与自动团注追踪法在确定肝脏多期扫描动脉早期时间上的价值,探讨多层螺旋CT肝脏血管成像的最佳扫描时间.方法将66例行腹部CT扫描的患者(男50例,女16例,年龄15～73岁,中位年龄49.5岁)分为三组,均行动脉早期、动脉晚期及肝实质期三期扫描,动脉早期的扫描时间分别采用常规延迟方法(20 s)及两种不同阈值/间隔时间(100 Hu/3 s;75 Hu/6 s)的团注追踪延迟方法确定.利用动脉早期及晚期数据分别进行肝动脉及门静脉的CT血管成像(CTA),并评价三组间图像质量的差异.结果两组团注追踪法及一组传统方法扫描获得的肝动脉及门静脉CTA三组间无显著差异.肝动脉及门静脉CTA质量最佳组延迟时间分别为(23.74±4.32) s及(41.78±3.68) s.结论团注追踪法确定扫描时间在获得血管成像方面与传统方法间尚无显著差异,传统延迟方法仍然是一种简便、可行的方法.动脉早期及动脉晚期的扫描时间可分别定为注药后22～25 s及41～43 s.     

CT中不同对比剂注射方案对小型猪腹部大血管及肝脏强化模式的影响

目的 比较不同对比剂注射方案对小型猪腹部大血管及肝实质强化峰值及达峰时间的影响。方法 对3头健康小型猪行3种方案交叉重复CT扫描,每组方案扫描6次,碘总量均为600 mgI/kg体质量,A组:碘浓度270 mgI/ml,注射流率3.4 ml/s,IDR 918 mgI/s;B组:碘浓度370 mgI/ml,注射流率2.5 ml/s,IDR 925 mgI/s;C组:碘浓度370 mgI/ml,注射流率3.4 ml/s,IDR 1258 mgI/s。比较不同注射方案下腹主动脉、下腔静脉、门静脉主干、肝中静脉及肝实质的强化峰值及达峰时间,对图像强化效果进行评分。结果 达峰时间腹主动脉C组小于B组,下腔静脉C组小于A和B组(P均<0.05),门静脉主干、肝中静脉和肝实质各组间差异均无统计学意义(P均>0.05);强化峰值腹主动脉、下腔静脉、门静脉主干和肝中静脉C组均大于A组和B组(P均<0.05),肝实质各组间差异无统计学意义(P均>0.05)。C组图像强化质量优于A组(P<0.05),余组间差异无统计学意义(P均>0.05)。结论 对比剂IDR可影响猪腹部大血管强化峰值,碘总量一定时,肝实质强化模式不受对比剂碘浓度、注射流率及IDR的影响。     

Radiation dose values for various coronary calcium scoring protocols in dual-source CT

Purpose The purpose of this study was to assess the radiation dose and associated image noise of previously suggested calcium scoring protocols using dual-source CT. Methods One hundred consecutive patients underwent coronary calcium scoring using dual-source CT. Patients were randomly assigned to five different protocols: retrospective ECG-gating and tube current reduction to 4% outside the pulsing window at 120 (protocol A) and 100 kV (B), prospective ECG-triggering at 120 (C) and 100 kV (D), and prospective ECG-triggering at 100 kV with attenuation-based tube current modulation (E). Radiation dose parameters and image noise were determined and compared. Results Protocol A resulted in an effective dose of 1.3 ± 0.2 mSv, protocol B in 0.8 ± 0.2 mSv, protocol C in 1.0 ± 0.2 mSv, protocol D in 0.6 ± 0.1 mSv, and protocol E in 0.7 ± 0.1 mSv. Effective doses were significantly lower (P < 0.001) with 100 kV when compared to 120 kV protocols, and were significantly lower (P < 0.001) for prospective versus retrospective ECG-gating. No significant difference was found between protocol D and E. Significant negative correlations were found between the CTDI_vol and heart rate for both retrospective ECG-gating protocols (protocol A: r = −0.98, P < 0.001; protocol B: r = −0.83, P < 0.001). The mean image noise was 29.0 ± 6.7 HU, with no significant differences between the five protocols. The image noise was significantly correlated with the body weight (r = 0.21, P < 0.05) and BMI (r = 0.31, P < 0.01). Conclusions Effective dose of calcium scoring using dual-source CT ranges from 0.6 to 1.3 mSv. Prospective triggering and lower tube voltage significantly reduces the radiation but yield similar image noise.     

CT of small bowel ischemia

We evaluated the computed tomographic (CT) features of small bowel (SB) ischemia and necrosis and correlated the findings with clinical outcome or patient prognosis. Sixty-eight surgically or angiographically proved cases of SB ischemia were retrospectively reviewed. The CT features of intestinal ischemia were divided into three groups: (A) thinned bowel wall with poor enhancement, intramural gas, or portal venous gas; (B) thickened SB wall without superior mesenteric vein thrombosis; and (C) thickened SB wall with superior mesenteric vein thrombosis or intussusception. The evaluated factors included bowel wall or mucosal enhancement pattern, SB dilatation, mesenteric edema, and CT evidence of narrowing or occlusion of the superior mesenteric artery or vein. The bowel necrosis rates and mortalities were compared with chi-square test. Oral contrast material was not administered. Intramural gas and SB dilatation were associated with a higher bowel necrosis rate (eight of eight, 100%, and 17 of 21, 81%, respectively) in group A. Poor mucosal enhancement of the thickened bowel wall indicated a higher bowel necrosis rate in groups B (six of seven, 86%) and C (12 of 12, 100%) than did normal mucosal enhancement. Only intramural gas was accompanied with a higher mortality (six of eight, 75%). Intramural gas of a thinned bowel wall and poor mucosal enhancement of a thickened small bowel wall are useful signs of bowel necrosis. Intramural gas would indicate poor patient prognosis.     

Helical CT anatomy of pancreatic arteries

Background: To assess the frequency of visualization of pancreatic arteries in the arterial phase of helical computed tomography (CT). Methods: The visibility of pancreatic and peripancreatic arteries in helical CT images was evaluated in 20 consecutive patients who had no evidence of pancreatic disease. CT examinations were performed by using a continuously rotating CT scanner and intravenous injection of contrast media. The scans were taken 35 s after the start of injection and with a table speed of 3 mm/s. Images were reconstructed in 3-mm section increments. Results: Frequently visualized arteries were the gastroduodenal, anterior and posterior superior pancreaticoduodenal, and right gastroepiploic arteries. Infrequently visualized arteries were the dorsal pancreatic, pancreatica magna, caudal pancreatic, transverse pancreatic, and common, anterior, and posterior inferior pancreaticoduodenal arteries. Conclusion: Helical CT enabled us to recognize small pancreatic arteries, and the evaluation of these arteries should be considered in the staging of pancreatic carcinoma. Received: 6 June 1995/Accepted: 22 July 1995     

不同浓度对比剂在正常兔脑CT灌注成像中的对照实验研究

目的 评价低速团注高浓度对比剂在兔脑CT灌注成像中的效果.方法 12只新西兰白兔随机分为3组,每组分别使用A方案(典迈伦400 mgI/ml,流率1.0 ml/s);B方案(400 mgI/ml,流率0.5 ml/s);C方案(300 mgI/ml,流率1.0 ml/s)行脑CT灌注成像,每次注射对比剂含碘量为0.5 g/kg体重.对比各方案脑CBF、CBV、MTT、灌注曲线峰值出现时间及峰值时大脑中动脉的CT值.结果 A、B、C三种方案测得脑CBF平均值分别为(69.8±11.4)、(72.2±12.8)、(74.8±10.3)ml/(min·100 g).CBV平均值分别为(2.5±0.3)ml/100 g,(2.7±0.2)ml/100g,(2.6±0.3)ml/100g.MTT平均值分别为(2.27±0.19)s,(2.30±0.26)s,(2.55±0.30)s,三种方案各灌注参数之间差异无统计学意义.灌注曲线峰值出现时间分别为4 s、5 s、5 s.大脑中动脉增强峰值分别为(193.5±5.1)、(164.7±5.2)、(163.0±7.1)HU,A方案高于B、C方案,B、C方案之间差异无统计学意义.结论 兔脑CT灌注成像中使用高浓度对比剂,可以降低注射速度而对灌注参数结果无明显影响;注射速度相同情况下,应用高浓度对比剂可使血管显示更清晰.     

低流率团注高浓度对比剂在兔脑CTA成像中的效果

目的 探讨低流率团注高浓度对比剂在脑CT血管成像(CTA)中的可行性.方法 18只新西兰白兔随机分为3组,实验组使用A方案(碘迈伦400 mgI/ml,流率0.5 ml/s);对照组分别使用B方案(300 mgI/ml,流率1.0 ml/s)或C方案(400 mgI/ml,流率1.0 ml/s),每次注射对比剂含碘量为0.5 g/kg体重,行脑CT同层动态扫描,获得兔大脑中动脉强化的时间-密度曲线.对比各方案兔大脑中动脉强化峰值到达时间(PT)及到达峰值时大脑中动脉的CT值.结果 大脑中动脉平均强化峰值分别为(164.67±5.16)HU、(163.00±7.13)HU、(193.50±5.13)HU,C方案高于A、B方案(P<0.01),A、B方案之间差异无统计学意义(P=0.63).三组方案测得大脑中动脉PT分别为5 s、5 s、4 s,C较A、B方案提前.结论 在兔脑CTA扫描中,使用高浓度对比剂,可以大大降低注射流率而对血管强化效果无明显影响;在注射流率相同情况下,应用高浓度对比剂可使血管显示更清晰.     

对比剂注射速率对64层CT冠状静脉成像质量的影响

目的评价不同流速对比剂注射方式对64层CT冠状静脉成像质量的影响。方法将25例志愿者分成A(n=13)、B(n=12)两组。分别给予对比剂速率3.5ml/s和4.5ml/s进行64层MSCT冠状静脉CTA检查。分析比较两组的冠状静脉及相伴性冠状动脉的显示率,显示积分及CT值。结果4.5ml/s组CT值优于3.5ml/s,两组心大静脉,心中静脉,左室后静脉及右冠状动脉远段的CT值有显著统计学差异(P<0.05)。两组冠状静脉的显示率均为100%。两组的冠状动脉,冠状静脉显示评分有统计学差异(P<0.05)。结论采用流速4.5ml/s显示冠状静脉及冠状动脉总体优于3.5ml/s,更适合显示动静脉关系。3.5ml/s流速更适合心功能不全的患者。     

胰腺癌瘤体强化程度与其恶性度的对照分析

目的探讨胰腺癌瘤体CT强化程度与其恶性度的关系。方法42例胰腺癌患者术前均行螺旋CT增强扫描,扫描延迟时间分别定为30s(胰腺实质期)、70s(门脉期)和180s(延迟期),以2.5～3.0ml/s速度团注对比剂100ml,观察胰腺癌胰实质期瘤体强化的程度和形式,结合胰腺癌病理组织学分级,对胰腺癌胰腺实质期的CT强化情况和病理级别作对照分析。结果胰腺高分化腺癌14例,平均胰腺-瘤体CT值差为(9.64±2.84)Hu,中分化腺癌16例,平均胰腺-瘤体CT值差(31.44±5.98)Hu,低分化腺癌12例,平均胰腺-瘤体CT值差(44.08±5.33)Hu,胰腺实质期病灶基本呈等密度强化13例,稍低密度强化15例,低密度强化伴小囊样改变9例,低密度强化伴大片坏死5例。胰腺癌实质期强化程度和形式与其病理分级有显著相关性,其秩相关检验结果为r=0.664(P<0.001)。结论胰腺癌实质期可以得到肿瘤的最大胰腺-瘤体密度差值,其瘤体强化程度和形式与其病理分级有显著相关性,即胰腺癌恶性度与其瘤体强化程度成反比。     

Three-dimensional spiral CT cholangiography with minimum intensity projection in patients with suspected obstructive biliary disease: comparison with percutaneous transhepatic cholangiography

Background: To evaluate the diagnostic potential of spiral computed tomographic (CT) cholangiography with minimum intensity projection (minIP) in the diagnosis of patients with suspected biliary obstruction. Methods: Nine consecutive patients with obstructive biliary disease were enrolled in this study. Spiral CT data (3-mm slice thickness, pitch 1∼2:1) obtained 65 s after the start of contrast medium injection (150 mL Ultravist 370, 3 mL/s) were reconstructed at 1-mm intervals. Three-dimensional (3D) CT cholangiography with minIP (3D CTC) was generated with a Siemens software package. The quality of 3D CTC in its ability to demonstrate the anatomic detail, the level of obstruction, and the presence or absence of isolated hepatic segments was evaluated using percutaneous transhepatic cholangiography as a gold standard. Results: In all patients, 3D CTC demonstrated dilated intrahepatic ducts up to tertiary branches. 3D CTC correctly diagnosed the level of biliary obstruction and demonstrated isolated segments in all patients. In determining the cause of biliary obstruction, one patient with hilar cholangiocarcinoma was misdiagnosed as having biliary invasion by hepatocellular carcinoma. Conclusion: 3D CTC with minIP can determine the level and cause of biliary obstruction. 3D CTC can be obtained from regular thin-section helical CT data and may be a strong competitor against diagnostic magnetic resonance cholangiography because of its superior resolution and information on adjacent soft tissues and the duct itself. Received: 7 July 2000/Accepted: 23 August 2000     

Detection of small vessels with electron beam computed tomographic angiography using 1.5 and 3 mm collimator protocols

Objectives To evaluate the effect of scanner collimation on the ability to detect small cardiac vessels using electron beam CT coronary angiography (EBA). Materials and methods EBA scans from 40 patients who underwent study on two separate occasions with 3 mm (initial scan) and 1.5 mm (follow-up scan) collimation protocols were analyzed. Vessels of <2 mm in diameter were identified. Results The 1.5 mm collimation allowed 3-D visualization of 129 vessels <2 mm in diameter, while 3 mm collimation only allowed visualization of 89 vessels (p<0.001). The right coronary artery branches and distal LAD segments though were not displayed satisfactorily in almost half of the 3-D studies with either protocol. Conclusions There was significant improvement in detection of small cardiac vessels with a 1.5 mm collimation EBA protocol compared to a 3 mm protocol. Both protocols though were insufficient for reliable visualization of the right coronary artery branches and distal LAD segments. Address for correspondence: Matthew J. Budoff, MD, Harbour-UCLA Research and Education Institute, 1124 W. Carson Street, RB2, Torrance, CA 90502, USA Tel.: +1-310-222-4107; Fax: +1-310-787-0448; E-mail: mbudoff@labiomed.org     

Customised weight-based volume contrast media protocol in CT of chest,abdomen and pelvis examination

IntroductionFixed volume (FV) contrast media administration during CT examination is the standard practice in most healthcare institutions. We aim to validate a customised weight-based volume (WBV) method and compare it to the conventional FV methods, introduced in a regional setting.Methods220 patients underwent CT of the chest, abdomen and pelvis (CAP) using a standard FV protocol, and subsequently, a customised 1.0 mL/kg WBV protocol within one year. Both image sets were assessed for contrast enhancement using CT attenuation at selected regions-of-interest (ROIs). The visual image quality was evaluated by three radiologists using a 4-point Likert scale. Quantitative CT attenuation was correlated with the visual quality assessment to determine the HU's enhancement indicative of the image quality grades. Contrast media usage was calculated to estimate cost-savings from both protocols.ResultsMean patient age was 61 ± 14 years, and weight was 56.1 ± 8.7 kg. FV protocol produced higher contrast enhancement than WBV, p < 0.001. CT images' overall contrast enhancement was negatively correlated with body weight for FV protocol while the WBV protocol produced more consistent enhancement across different body weight. More than 90% of the images from both protocols were graded “Excellent”. WBV protocol also enabled a 28% cost reduction with cost savings of US$1238.ConclusionThe customised WBV protocol produced CT images which were comparable to FV protocol for CT CAP examinations. A median CT value of 100 HU can be an indicator of good image quality for the WBV protocol.     

肝细胞癌与腹主动脉强化峰值时间的相关性

目的 探讨肝细胞癌强化峰值时间与腹主动脉强化峰值时间的相关性.方法 对43例确诊为肝细胞癌的患者,应用64层螺旋CT行常规肝脏平扫,选取肿瘤最大径层面,再以该层面为中心行持续动态增强扫描,取肿瘤强化最高区域和同层面腹主动脉中心分别作为感兴趣区(ROI),绘制二者的时间-密度曲线(TDC)并计算其强化峰值时间.结果 43例患者肝细胞癌的强化峰值时间为(30.04±6.36)s,腹主动脉的强化峰值时间为(23.38±4.92)s;肝细胞癌的强化峰值时间与腹主动脉的强化峰值时间呈正线性相关(r=0.662,P<0.05);肝细胞癌的强化走势有三种形式,23.26%与腹主动脉相似.结论 肝细胞癌的强化峰值时间与腹主动脉的强化峰值时间具有一定的相关性.     

64层螺旋CT冠脉CTA对比剂注射方案优化

目的 比较相同碘负荷情况下,不同对比剂注射方案以及相同碘浓度情况下,不同对比剂注射流率在64层螺旋CT冠脉CTA的应用效果.方法 58例可疑冠心病病例分为3组,分别采用不同对比剂注射方案进行冠脉CTA检查;对血管强化程度、重建血管清晰度进行评价.结果 300 mgI/ml×5 ml/s和370 mgI/ml×4 ml/s两种注射方案冠脉平均强化水平相似,约350～370 HU,两者差异不具有统计学意义.370 mgl/ml×4 ml/s和370 mgI/ml×3 ml/s两种注射方案在升主动脉,左、右冠状动脉主干平均强化程度分别为360 HU左右和330 HU左右,但两组间的差异不具有统计学意义,两组重建血管清晰度无统计学差异,96.3%的重建血管能够满足诊断.结论 应用370 mgI/ml×3 ml/s注射方案相当的单位时间碘负荷量,平均强化程度330 HU,能够满足64层螺旋CT冠脉CTA检查.     

A dual CT‐MR dendrimer contrast agent as a surrogate marker for convection‐enhanced delivery of intracerebral macromolecular therapeutic agents

The feasibility of using Gd dendrimer‐based macromolecules (Gd‐G8 dendrimer) as a dual CT and MR contrast agent for monitoring convection‐enhanced delivery of therapy in the brain is evaluated both in vitro and in vivo with optimal dosing established. In vitro CT attenuation values of the Gd‐based agents (～6.0 HU mM ^?1) were ～1.6 times greater than iodine‐based agents and the attenuation of the Gd‐DTPA was comparable to Gd‐G8 dendrimer. Visible enhancement was observed on both CT and MR using Gd‐G8 dendrimer over a range of 23–78 mM ; however, a concentration of at least 47 mM in Gd was required for adequate delineation of the injection site on both CT and MR. MR offers greater sensitivity than CT in estimating the volume of distribution (V_d) and effectively quantified the agent's concentration and diffusion using T₁ mapping at much lower concentrations of Gd (<10 mM in [Gd]). Copyright © 2008 John Wiley & Sons, Ltd.     

对比分析胃间质瘤与炎性纤维性息肉CT征象

目的 对比分析胃间质瘤（GST）与胃炎性纤维性息肉（IFP）CT征象。方法 回顾性分析经手术病理证实的80例GST患者和14例IFP患者的临床、病理及CT资料,比较其CT征象、年龄及CT值差异。结果 GST与IFP间,肿瘤最大径和平扫、动脉期、静脉期CT值、肿瘤形态、生长方式、囊变、周围淋巴结转移、肿瘤血管、强化方式、强化程度差异均有统计学意义（P均<0.05）。GST形态不规则,瘤体相对较大,平扫密度较高,以腔外生长为主,易坏死囊变及周围淋巴结转移,内部血管丰富,明显不均匀强化。二者间肿瘤边界、钙化、出血、溃疡、延迟期CT值及患者年龄差异均无统计学意义（P均>0.05）。结论 CT征象可作为鉴别诊断GST与IFP的影像学参考依据。     

运用正交试验法研究肝脏动态CT增强扫描最佳参数

目的 研究肝脏动态CT增强扫描的最佳参数。方法 选择3因素2水平正交试验表(L_82~7),安排40例病人造影检查,分析不同造影剂注射速度(2ml/秒、4ml/秒)、注射时相(单、双相)及延迟时间(15秒、30秒)对造影观察指标的影响。结果 造影剂注射速度为4ml/秒及延迟30秒扫描可获得较高的肝脏增强峰值(p<0.05);采用2ml/秒的注射速度及双相注射可获得较长的到达肝脏增强峰值的时间;采用2ml/秒的注射速度可获得较长的平衡期及最佳扫描间隙。结论 2ml秒注射速度、双相注射及延迟30秒扫描可作为肝脏动态CT增强扫描的最佳参数组合。     

基于不同能量窗和准直器的177Lu-Dotatate SPECT/CT定量采集条件

目的 探讨基于不同能量窗和准直器的¹⁷⁷Lu-Dotatate SPECT/CT定量采集条件。方法 以微球和背景放射性浓度比为12∶1的国际电工委员会体模为实验对象。采用低能高分辨率（LEHR）、中能通用（MEGP）和高能通用（HEGP）3种类型准直器采集SPECT图像，主能窗为113 keV、208 keV和113 keV+208 keV，能宽均为20%，散射线采用CT衰减校正和三能窗法校正，形成9种采集条件：LEHR_113、LEHR_208、LEHR_113+208、MEGP_113、MEGP_208、MEGP_113+208、HEGP_113、HEGP_208和HEGP_113+208。定量分析9种采集条件下采用部分容积校正后的微球与背景放射性浓度比值、相对误差和转换系数。结果 LEHR_208对应SPECT图像对比度最差，MEGP_208和MEGP_113+208对应图像视觉分辨率最佳。9种采集条件所得放射性浓度平均比值均低于真实值（F=2.659，P=0.040）。MEGP_113+208所得放射性浓度比值相对误差最小[（－1.33±6.40）%]，LEHR_208的相对误差最大[（－58.34±14.42）%]。不同采集条件所得放射性转换系数差异有统计学意义（F=4.846，P=0.003）。结论 不同采集条件对¹⁷⁷Lu-Dotatate SPECT/CT定量显像结果影响显著，MEGP准直器联合113 keV+208 keV能窗所得图像质量最佳，放射性浓度比值最接近真实值。