低浓度对比剂大螺距前门控双源CT冠状动脉成像初步研究

目的:评价低浓度对比剂Flash双源CT大螺距冠状动脉成像联合应用低kV和迭代重建算法对血管强化程度、图像质量和辐射剂量的影响.方法:对120例体重指数(BMI)＜25 kg/m2、心率≤65次/分且稳定的患者进行前瞻性心电触发大螺距双源CT冠状动脉扫描,检查者随机分成低浓度对比剂组(A组,60例)和高浓度对比剂组(B组,60例).A组对比剂使用碘克沙醇(浓度为270mg I/mL),管电压为80 kV,图像重建采用迭代重建算法(SAFIRE);B组对比剂使用碘普罗胺(浓度为370mg I/mL),管电压为100 kV,图像重建采用滤波反投影算法(FBP).两组图像均测量左右冠状动脉开口处、升主动脉根部及心底层面的胸主动脉CT值,并比较两组图像的噪声、信噪比(SNR)、对比噪声比(CNR)、主观图像质量评分和有效辐射剂量.结果:碘克沙醇270组各解剖部位平均强化CT值均明显高于碘普罗胺370组,差异均具有统计学意义(P＜0.05).碘克沙醇270组图像噪声、SNR、CNR较碘普罗胺370组略高,但差异均无统计学意义(P＞0.05).两组主观图像质量评分分别为(1.62±0.69)和(1.51±0.65),差异克统计学意义(P＞0.05).碘克沙醇270组有效辐射剂量较碘普罗胺370组明显降低[分别为(0.25±0.05) mSv和(0.55±0.11) mSv,P＜0.001],低浓度组辐射剂量较高浓度组降低了54.5％.结论:当联合应用低kV和迭代重建算法时,即使使用低浓度对比剂(270 mg I/mL)进行Flash双源CT大螺距冠状动脉成像,依然可以提高血管的对比强化效果且不降低图像质量,还能大幅度降低有效辐射剂量.     

基于同济指数法结合等渗对比剂行CCTA的优势研究

【摘要】目的：探讨基于同济指数法结合等渗对比剂行冠状动脉CT血管造影（CCTA）检查的优势。方法：131例受检者在东芝Aquilion Vision 320排CT扫描仪上行CCTA检查,根据检查中使用的对比剂浓度不同将受检者分为270组(270mg I/mL碘克沙醇)和370组(370mg I/mL碘克沙醇)两组,其中270组92例,370组39例,并基于同济指数法个性化静脉团注对比剂和生理盐水。比较270组与370组患者的年龄、性别、身高、体重以及检查前、中、后期的舒张压、收缩压、心率变化情况和对比剂的注射压力等指标;采用双盲法对图像质量进行主观评价,测定相关血管、位点的CT值并对图像进行客观评价。结果：270组与370组受检者的年龄、性别、体重、身高差异均无统计学意义（P＞0.05）,检查前、中、后期收缩压、舒张压差异均无统计学意义（P＞0.05）;检查前期心率差异无统计学意义（P＞0.05）;两组受检者检查中期心率分别为（73.12±16.03）次/min和（79.69±18.90）次/min（P＜0.05）,检查后期心率分别为（74.27±14.72）次/min和（80.41±18.10）次/min（P＜0.05）。两组受检者对比剂的注射压力分别为（84.94±39.95）kPa和（143.05±59.73）kPa,270组显著低于370组,差异有统计学意义（P＜0.05）。两组图像的主观和客观评价均符合诊断标准。结论：行CCTA检查时,基于同济指数法使用等渗对比剂(270mg I/mL碘克沙醇)可以在保证冠状动脉图像质量符合标准的前提下,显著减少碘对比剂用量,降低注射压力,并使受检者心率相对降低且平稳,从而降低对比剂不良反应的发生率以及提高受检者的舒适度。     

观察静脉注射碘对比剂对冠脉CTA检查患者心率的影响

目的：观察冠状动脉CTA成像中静脉注射碘对比剂时患者心率的变化。方法：搜集因临床诊断需求而行冠状动脉CTA检查的89例连续患者的病例资料,观察cT增强扫描前屏气状态下心率（基础心率）、扫描过程中注射对比剂时屏气状态下心率（注射时心率）、扫描结束10min后屏气状态下心率（恢复期心率）。比较不同时间点患者的心率变化。根据患者基础心率分为两组,A组心率〈65次／分,B组心率≥65次／分,对两组患者的心率变化进行比较。结果：89例患者,平均基础心率（68．24±8．60）次／分,平均注射时心率（64．48土8．20）次／分,平均恢复期心率（67．03±9．08）次／分,三个时间点的心率差异有统计学意义（P〈0．05）。三组数据之间两两比较,基础心率、恢复期心率之间的差异无统计学意义,但二者与注射时心率的差异都有统计学意义（P〈0．05）,注射时心率降低。A组注射时心率较基础心率变化（-1．55±4．67）次,B组心率变化（-5．05±4．30）次,两组之间差异具有统计学意义（P〈0．05）。结论：静脉注射碘对比剂时可引起心率变化,基础心率越高的患者,注射碘对比剂时心率下降幅度越大。     

CT增强扫描碘对比剂不良反应的临床表现分析

目的探讨CT增强扫描非离子型碘对比剂不良反应及临床特点。方法选取我院行CT增强和血管CTA增强扫描46例碘对比剂不良反应患者临床资料,分析其原因及采取措施。结果 46例患者中,轻度不良反应占58.69%(27/46);中度不良反应占34.78%(16/46);重度不良反应占6.52%(3/46)。碘普罗胺不良反应的例数高于碘克沙醇与碘佛醇,组间比较差异具有统计学意义(P0.05)。碘普罗胺急性不良反应的例数高于碘克沙醇与碘佛醇,组间比较差异具有统计学意义(P0.05),而碘克沙醇迟发性过敏反应多见(P0.05)。所有患者经休息,对症处理及抗过敏治疗,均治愈好转。结论为提高碘对比剂使用的安全性,应早预防及时进行临床干预,确保用药安全。     

对比剂注射技术在冠状动脉CTA成像中的应用

目的 探讨对比剂注射技术在冠状动脉CTA成像中的应用.方法 收集150例行冠状动脉CTA成像患者,随机抽取50例二期相对比剂注射技术为A组,三期相对比剂注射技术分B1组(1.0 mL/kg)和B2组(0.8mL/kg)各50例.A组:一期碘普罗胺1.0 mL/kg,注射速率4.5mL/s;二期生理盐水30 mL,注射速率4.0 mL/s.B1组:一期碘普罗胺按1.0 mL/kg对比剂总量的75％,注射速率4.5 mL/s;二期碘普罗胺按对比剂注射总量的25％+生理盐水按1:1浓度,注射速率4.0 mL/s;三期生理盐水25 mL,注射速率3.5 mL/s.B2组:一期碘普罗胺(0.8 mL/kg)按对比剂注射总量的75％,注射速率4.5 mL/s;二期碘普罗胺按对比剂注射总量的25％+生理盐水按1:1浓度,注射速率4.0 mL/s;三期生理盐水25 mL,注射速率4.5 mL/s.将图像根据5分制评分标准,评分在3分及以上的受检者纳入研究.结果 3种对比剂注射技术的比较显示B2组与A组、B1组对比剂用量有统计学意义(P＜0.05).右心房、左右心室、主动脉根部和冠状动脉密度A组与B1组、B2组比较,右心房与右心室密度差异有统计学意义(P＜0.05).结论 冠状动脉CTA成像采用三期相对比剂优化注射技术,在保证图像质量的基础上,可以减少对比剂用量.     

不同浓度碘克沙醇在肾动脉CT增强扫描中的应用及对肾功能的影响

目的探讨不同浓度碘克沙醇在肾动脉CT增强扫描中的应用。方法选取我院肾动脉增强CT扫描的126例患者,按检查顺序将受试者分为大剂量组、中剂量组、小剂量组。大剂量组患者注射350mg I/ml的碘克沙醇[1],中剂量组注射300mg I/ml的碘克沙醇,小剂量组注射270mg I/ml的碘克沙醇,每组各42例患者。三组患者在进行CT增强前的12h和进行CT增强后的72h均测定其血尿素氮(BUN)、血肌酐(Scr)、肾小球滤过率(GFR),比较三组前后BUN(mmol/L)、Scr(μmol/L)、GFR(ml/min)的变化情况及三组间的对比情况,同时比较三组间不良反应的发生率情况。结果注射碘克沙醇72h后,BUN、Scr和GFR增长幅度小于注射碘克沙醇前BUN、Scr和GFR水平的25%,且注射碘克沙醇72h后组间对比P值大剂量组*中剂量组(P=0. 56)、大剂量组*小剂量组(P=0. 73)、小剂量组*中剂量组(P=0. 63)均大于0. 05,差异无统计学意义。大剂量组患者有4(9. 52)例出现轻度不良反应,中剂量组患者有2(4. 76)例出现轻度不良反应,小剂量组患者有2例出现轻度不良反应。组间比较大剂量组*中剂量组(P=0. 671)、大剂量组*小剂量组(P=0. 671)、小剂量组*中剂量组(P=0. 608),差异均无统计学意义;大剂量组患者造影清晰度较高,而中剂量组和小剂量组有部分患者病灶不清晰或遗漏。结论在肾动脉CT增强扫描中合理选择对比剂浓度,在保证降低并发症同时,提高图像质量。     

静脉注射碘克沙醇(270mgI/ml)肾脏不良反应的临床观察

目的：探讨静脉注射碘克沙醇（270mgI／m1）对肾功能的影响。方法：回顾性分析行冠状动脉CTA检查的432例连续患者的病例资料,根据对比剂的使用情况将研究对象分为：等渗对比剂组,注射碘克沙醇（270mgI／m1）,115例;低渗对比剂组,注射碘帕醇（370mgI／m1）,317例。搜集同期住院患者中行平扫CT的110例连续患者资料作为对照组。比较3组患者的临床特点,检查前后血清肌酐（Scr）和估计肾小球滤过率（eGFR）的变化,以及对比剂肾病（CIN）的发病率。结果：432例患者均未发生严重的急性不良反应。三组年龄差异有统计学意义（P〈O．05）：其中等渗对比剂组平均年龄较低渗对比剂组及对照组大（P〈0．017）。三组的性剐构成比差异无统计学意义（P〉0．05）。三组闻CIN危险因素的差异有统计学意义（P〈O．05）：其中等渗对比剂组有危险因素的患者比例较低渗对比剂组及对照组多（P〈0．017）;低渗对比剂组有危险因素的患者比例较对照组多（P〈0．017）。CT检查后各组Scr和eGFR的变化（与检查前基线值比较）：等渗对比剂组Scr下降,eGFR升高（P〈0．05）;低渗对比剂组检查后Scr升高（P〈0．05）;对照组Scr及eGFR的变化均无统计学意义。等渗对比剂组、低渗对比剂组cIN发病率分别为2．6％、7．9％。13．6％的平扫患者出现了符合CIN诊断标准的Scr升高。等渗对比剂组CIN的发病率明显低于对照组（P〈0．017）。等渗对比剂组与低渗对比剂组、低渗对比剂组与对照组cIN发病率差异均无统计学意义。结论：静脉注射等渗对比剂碘克沙醇（270mgI／m1）对肾功能没有影响,静脉注射低渗对比剂碘帕醇（370mgI／m1）后Scr升高,两组的CIN发病率接近。不注射碘对比剂的CT检查患者,在检查后也可能由于其他因素导致肾功能降低,其“CIN”的发病率比注射等渗对比剂组高,与低渗对比剂组接近,因此判断CIN时应除外其他影响因素,避免对CIN的过度诊断。     

多层CT评估心肌活力：兔模型中单体与双体对比剂的个体内比较

为研究不同碘离子对比剂对心肌活力评估的影响，在6只兔上用外科手术建立了急性心肌梗死模型。45min内，以600mgI／kg体质量的对比剂重复进行心脏多层CT增强检查（64×0．6mm，80kV，680mAs）。动物随机应用碘普罗胺300和碘克沙醇320。测量健康及梗死心肌的衰减值。计算心肌梗死大小，并与四唑硝基兰（nitroblue tetrazolium，NBT）染色的标本比较。     

基于动态容积 CT 前瞻性心电门控对快心率冠状动脉 CTA 的观察

目的：探讨心率>70次/min 的患者动态容积 CT 前瞻性心电门控技术的可行性。方法收集118例心率>70次/min患者的一般资料。所有患者行320容积扫描,前瞻性心电触发扫描模式,R 波后250~400 ms 多扇区采集,管电压100 kVp,自动管电流调节,对比剂采用碘克沙醇(370 mg I/mL)。记录所有患者的辐射剂量。将冠状动脉分为15个节段,由2名影像科医师测量冠状动脉 CT 值、图像评分。对结果进行统计学分析。结果各组间性别、年龄、体质量无显著性差异。心律整齐,心率>70次/min 者满足诊断率83.05%。心率>70次/min 组、心率>75次/min、心率>85次/min 组的图像主观评分分别为(4.23±0.72)分,(3.54±1.22)分,(1.87±0.74)分。各组间评分差异无统计学意义(F=5.125,P =0.0503)。辐射剂量随心率增加。结论动态容积 CT 采用前瞻性心电触发扫描模式,对心率>70次/min 患者行冠状动脉 CT 血管成像(CTA)检查可以得到满足临床诊断要求的图像质量。     

水化加碘克沙醇对轻度肾功能不全患者肾功能的影响

目的 评价轻度慢性肾功能不全患者行冠状动脉造影时,使用碘克沙醇作为对比剂是否对肾功能造成影响.方法 对36例慢性肾功能不全患者行冠状动脉造影时,选择碘克沙醇作为对比剂,并在术前12 h及术后12 h对患者进行水化,对其术后48 h及术后96 h肾功能进行复查,与术前肾功能相对比,了解其对肾动能是否造成影响.结果 术前患者肌酐( 174.20 ±35.99) μmol/L,内生肌酐清除率(44.75 ±10.89) ml/(min·1.75 m2);术后48 h肌酐(169.53±36.74) μmol/L,内生肌酐清除率(44.54±10.57) ml/(min·1.75 m2);术后96 h肌酐(169.9±38.10) μmol/L,内生肌酐清除率(44.42±11.73) ml/(min·1.75 m2),两者与治疗前比较差异均无统计学意义(P＞0.05).结论 在对轻度慢性肾功能不全患者进行冠状动脉造影时,选择碘克沙醇作为对比剂,其安全性高,不会对该类患者肾功能造成明显影响.     

A comparison of the efficacy and safety of iopamidol-370 and iodixanol-320 in patients undergoing multidetector-row computed tomography

OBJECTIVES: To prospectively compare the effects on heart rate (HR) and contrast enhancement efficacy of iopamidol-370 and iodixanol-320 in contrast-enhanced, multidetector-row computed tomography (CE-MDCT). METHODS: IMPACT is a multicenter, double-blind study involving 166 patients undergoing CE-MDCT of the liver (n = 121) or peripheral arteries (n = 45) randomized to receive equi-iodine doses (40 gI) of iopamidol-370 or iodixanol-320 intravenous at 4 mL/s. CE-MDCT was performed using 16-MDCT scanners according to predefined imaging protocols. HR was measured with the patient in the supine position before and continuously for 5 minutes after contrast medium administration. Mean and peak increases in HR and the proportion of subjects with predefined HR increases (>5 to <10, 10 to <15, 15 to <20, >20 bpm) were compared in the 2 populations. Liver images were assessed by 2 independent, blinded readers for contrast enhancement [Hounsfield unit (HU)], using predefined regions-of-interest during the arterial and portal-venous phase of enhancement. RESULTS: Effects on HR: Eighty-four subjects received iopamidol-370 whereas 82 received iodixanol-320. Mean age, gender distribution, weight, total iodine dose, dose/body weight, concomitant medications and use of beta-blockers were comparable in the 2 groups. Mean baseline HR was similar in the 2 groups (iopamidol-370: 72.3 +/- 12.5 bpm; iodixanol-320: 74.5 +/- 11.9 bpm). Mean changes from baseline to peak postdose were similar in the 2 groups (8.0 +/- 9.3 bpm after iopamidol-370 and 8.4 +/- 14.7 after iodixanol-320, P = 0.72). The proportion of subjects in each group having increases of <5, >5 to <10, 10 to <15, 15 to <20, or >20 bpm was comparable (P = 0.87). Two subjects experienced postcontrast tachycardia (HR increase >70 bpm, peak HR of 146 and 164 bpm), both in the iodixanol-320 group (2.4%). Contrast Enhancement: Of the 121 patients undergoing liver CT, 60 received iopamidol-370 whereas 61 received iodixanol-320. Mean age, gender distribution, weight, total iodine dose, and dose/body weight were comparable in the 2 groups. Iopamidol-370 provided significantly higher HU values in abdominal aorta during the arterial phase of enhancement for both readers [R1: 301.3 +/- 80.2 vs. 273.6 +/- 65.9 HU, 95% confidence interval (6.1-56.8), P = 0.02; R2: 302.0 +/- 73.6 vs. 275.1 +/- 62.9 HU, 95% confidence interval (2.3-51.3), P = 0.03]. No significant difference was observed between the 2 contrast medium during the portal venous phase of enhancement. CONCLUSIONS: When the same injection rate and iodine dose is used, the effects on HR of bolus intravenous injections of iopamidol-370 and iodixanol-320 were similar. Iopamidol-370 provides significantly greater enhancement during the arterial phase and similar enhancement during the portal venous phase compared with iodixanol-320.     

Coronary stent evaluation with coronary computed tomographic angiography: Comparison between low-osmolar,high-iodine concentration iomeprol-400 and iso-osmolar,lower-iodine concentration iodixanol-320

BackgroundReliability of coronary angiography by multidetector row CT (MDCT-CA) for stent evaluation is still a matter for debate, and it is unknown whether contrast medium characteristics may affect diagnostic performance of MDCT-CA.ObjectiveWe compared iomeprol-400 with iodixanol-320 to evaluate coronary stents with MDCT-CA.MethodsWe randomly assigned 254 patients undergoing coronary stent follow-up with the use of MDCT-CA to iomeprol-400 at 5.0 mL/sec flow rate (group 1; n = 83), iodixanol-320 at 6.2 mL/sec flow rate (group 2; n = 87), and iodixanol-320 at 5.0 mL/sec flow rate (group 3; n = 84). Heart rate (HR) immediately before and at the end of scanning, HR variation, premature heart beats, and heat sensation by visual analog scale during scanning were recorded. Mean attenuation was measured in the aortic root and coronary arteries. Image quality score and type of artifacts were assessed.ResultsMean attenuation was significantly lower in group 3 than in the other groups. In group 3, stent evaluability was significantly higher and artifact rate was significantly lower than in group 2 (99% vs 91% and 4% vs 15%) and group 1 (99% vs 92% and 4% vs 17%), respectively, mainly because of a significant lower rate of beam-hardening artifacts (3 cases in group 3 vs 22 and 27 in groups 2 and 3, respectively). In group 3, visual analog scale, HR at the end of imaging, and number of patients with premature heart beats during the scan were significantly lower than in the other groups.ConclusionsIodixanol-320 provides better image quality of coronary stents, allowing higher MDCT-CA evaluability, than iomeprol-400.     

320排CT冠状动脉成像平均心率对图像质量和辐射剂量的影响

目的:探讨不同心率条件下320排容积CT冠状动脉血管成像的图像质量和辐射剂量.方法:将259例临床怀疑或确诊的冠状动脉疾病的患者(含35例心律失常患者)分为3组;A组79例,心率≤65次/分;B组120例,65＜心率＜80次/分;C组60例,心率≥80次/分.扫描完成后选用最佳的重建时相,对冠状动脉进行容积再现(VR)...     

Timing of exposure in angiographic computed tomography

Visualization of heart chambers or the abdominal arterial phase on one of two CT-scans was achieved in 89.4% of 169 injections (91 patients) using only 30 ml of contrast medium (370 mg iodine/ml), when the start of scanning was accurately timed at predicted bolus peak concentration. Normal arrival times and numer of transit cycles to the bolus concentration maximum in the right (RV) and left ventricle (LV) after injection of a small radionuclide bolus of technetium-99 m were related to the patient's heart rate (HR) in a group of 200 patients. For the RV, mean arrival times varied significantly between 2.31 (HR: 90–109 beats per minute) and 3.46 seconds (HR: 50–59 beats per minute), mean number of transit cycles between 4.1 and 3.5. For the LV, mean arrival times varied significantly between 6.92 (HR: 90–109 beats per minute) and 11.37 seconds (HR: 50–59 beats per minute), and the mean number of transit cycles between 11.5 and 10.7. Washout from the LV lasted between an average of 9.2 (HR: 90–109 beats per minute) and 8.5 cycles (HR: 50–59 beats per minute). Contrary to actual transit times, there was no significant difference in the number of transit heart cycles for heart rates between 60 and 109 beats per minute, so that to determine the scan starting time, the patient's cycle length (60 divided by heart rate) had only to be multiplied by the corresponding normal value of transit cycles, i.e., four for the RV, 11 for the LV, and 13 for the abdominal arteries. By applying the estimated values, the result was negative on two successive scans in only 10.6% because of failure in coordination on the part of the operators or bolus transit delays (due to severe heart failure, severe lung disease, recent thoracotomy, or small veins disease). With automatic triggering of the scanner by a timer and injector and with a flush of saline after injection, results can be further improved. Radionuclide studies supported by grant of the Internal Department of the Government of the Federal Republic of Germany     

320排CT冠状动脉成像心率(律)对图像质量和辐射剂量的影响

目的:探讨不同心率(律)的条件下,320排容积CT冠状动脉血管成像的图像质量和辐射剂量。方法:将259例临床怀疑或确诊冠状动脉疾病的患者分为两组:窦性心律组(S组)220例;心律失常组(N组)39例。其中S组分为:A组79例,心率<65bpm;B组102例,65≤心率<80bpm;C组39例,心率≥80bpm。扫描完成后选用最佳的时相,对冠状动脉进行容积重组(VR)、多平面重组(MPR)、曲面重组(CPR)。按照4分法将图像质量分类并统计分析,比较各组冠状动脉血管段的优良率、可评价性;记录各组的辐射剂量,比较辐射剂量的差异。结果:S组与N组之间冠状动脉血管段优良率和可评价性的差异均无统计学意义。所有病例共有9段冠状动脉不可评价。所有病例平均辐射剂量为(9.49±6.54)mSv;S组和N组平均辐射剂量分别为(8.45±5.7)mSv、(15.36±7.79)mSv,两组之间辐射剂量差异具有统计学意义(t=-5.29,P=0.000)。窦性心律各组辐射剂量差异具有统计学意义(2=126.43,P=0.000)。结论:320排CT能较好适应心率(律)变化,保证诊断图像质量,对于心率<65bpm以下的窦性心律患者辐射剂量降低显著。     

320排冠状动脉CTA中等渗低浓度对比剂用量的合理选择

目的：探讨在320排冠状动脉 CTA 检查中降低等渗低浓度对比剂用量的可行性。方法选取心率≤70次/min、心律规则、体质量指数(BMI)≤24 kg/m2患者64例行320排冠状动脉 CTA,采用100 kVp 管电压,威视派克270 mg I/mL 对比剂,使用前瞻性心电门控技术,自适应迭代剂量减低算法重建。根据对比剂用量的不同将其分为3组：A 组22例注射50 mL 固定剂量对比剂,注射速率为5.0 mL/s;B 组21例按0.7 mL/kg 计算剂量,注射速率为4.5 mL/s;C 组21例按0.6 mL/kg 计算剂量,注射速率为4.0 mL/s。采用单因素方差分析比较3组间感兴趣区(ROI)的 CT 值、信噪比(SNR)、对比噪声比(CNR)以及冠状动脉节段评分的差异,并对患者碘摄入量进行比较。结果3组间患者的年龄、性别比、BMI、心率等指标差异无统计学意义(P >0.05),对比剂用量及注射时间的差异有统计学意义(P <0.05)。ROI 的 CT 值从 A 组到 B 组再到 C 组呈下降趋势,A 组明显高于 B 组和 C组,差异均有统计学意义(P <0.05),而 B 组与 C 组间差异无统计学意义(P >0.05)。3组间冠状动脉节段评分、SNR 和 CNR 的差异无统计学意义(P >0.05)。C 组的碘总量和碘注入率最低。结论在320排 CT 冠状动脉血管成像中,对于心率≤70次/min、BMI≤24 kg/m2患者,按0.6 mL/kg 剂量注射等渗低浓度对比剂,图像质量能满足诊断要求,明显减少了患者的碘摄入量,降低了发生对比剂肾病的风险。     

无心率控制第二代双源CT前门控序列扫描冠状动脉造影的临床评价

目的：分析无心率控制下的患者不同采集窗设置,明确前瞻性心电门控序列扫描对图像质量与辐射剂量的影响。方法前瞻性选取75例患者行CT冠状动脉造影(CTCA)扫描,中位年龄55岁。所有患者均无心率控制。心率≤65次/min采集期相设置为65%~75%,65次/min<心率≤80次/min采集期相设置30%~75%,心率>80次/min采集期相设置为35%~45%。分析患者辐射剂量与冠状动脉图像质量主观评分。结果75例患者有效剂量(ED)为(2.44±1.21)mSv,其中A组为(1.54±0.41)mSv,B组为(3.57±0.53)mSv,C组为(1.64±0.27)mSv;A组vs B组P=0.000,A组vs C组P=0.854,B组 vs C组P=0.000。75例患者共评价1043段冠状动脉节段,平均显示13.9段,(3.66±0.51)分。其中A组(3.75±0.44)分;B组(3.60±0.54)分;C组(3.38±0.67)分;A组vs B组P=0.000,A组vs C组P=0.004,B组vs C组P=0.032。结论前瞻性心电门控序列扫描通过适应不同心率修改采集窗范围可以获得可评估的图像质量,并且避免不必要的辐射剂量产生,值得进一步研究与应用。     

不同心率下双源CT冠状动脉成像最佳相位窗的研究

目的探讨双源CT冠状动脉成像在不同心率下最佳相位窗的选择。方法对100例临床怀疑冠心病或冠状动脉病变患者进行双源CT冠状动脉回顾性心电门控成像扫描,扫描后数据分别按R-R间期10%、20%、30%、40%、50%、60%、70%、80%、90%的相位进行后处理重组,图像行MPR、MIP、容积再现技术（VRT）重组,利用Inspace软件及Circulation软件分析,将图像质量分为4级,按冠状动脉分段标准评价各个节段的图像质量。扫描时记录心率,100例患者心率小于等于60次/min为1组,心率大于60次/min而小于等于80次/min为2组,心率大于80/min而小于等于100次/min为3组,心率大于100次/min为4组。分析观察不同心率组的各时相冠状动脉评分趋势。结果 1、2组70%相位图像质量最好,3、4组40%相位图像质量较好。冠状动脉的图像质量评分与心率有一定的相关性。结论心率越慢图像质量越好,心率越快图像质量越差。最佳时相的选择可以提高诊断冠心病的准确率。     

Stent evaluation by coronary computed tomography angiography: a comparison between Iopamidol-370 and Ioversol-320 hypo-osmolar iodine concentration contrasts

Objective:Qualitative and quantitative image analysis between Iopamidol-370 and Ioversol-320 in stents´ evaluation by coronary computed tomography angiography (CTA).Methods:Sixty-five patients with low-risk stable angina undergoing stent follow-up with coronary CTA were assigned to Iopamidol I-370 (n = 33) or Ioversol I-320 (n = 32) in this prospective, double-blind, non-inferiority, randomized trial. Stent lumen image quality was graded by 5-point Likert Scale. Lumen mean attenuation was measured at native coronary segments: pre-stent, post-stent, distal segments and at coronary plaques. Lumen attenuation increase (LAI) ratio was calculated for all stents. Heart rate (HR) variation, premature heart beats (PHB), heat sensation (HS), blooming and beam hardening were also assessed.Results:Image quality was similar between groups, with no significant difference (Likert score 4.48 ± 0.75 vs 4.54 ± 0.65, p = 0.5). There were similarities in LAI ratio between I-370 and I-320 (0.39 ± 0.42 vs 0.48 ± 0.44 HU, p = 0.08). Regarding lumen mean attenuation at native coronary segments, a significant difference was observed, with I-320 presenting lower values, including contrast mean attenuation in distal segments. After statistical multivariate analysis, three variables correlated with stent image quality: 1) stent diameter, 2) HR variation and 3) stent lumen LAI ratio.Conclusions:There was no significant difference between Iopamidol-370 mgI ml⁻¹ and Ioversol-320 mgI ml⁻¹ contrasts regarding overall stent lumen image quality, which was mainly influenced by stent diameter, HR and LAI ratio. Advances in knowledge: Coronary CTA allows adequate stents'' visualization and image quality is influenced by stent diameter, HR variation and LAI ratio.Stents'' image quality showed no difference between different concentration contrasts (I-370 vs. I-320); however, higher concentration contrasts may provide an improved overall visualization, especially regarding coronary distal segments.