平板DSA低剂量技术在冠状动脉造影中的应用

目的：探讨低剂量技术应用于平板DSA冠状动脉造影的可行性。方法：将70例似行冠状动脉造影的患者随机分成研究组(35例)和对照组(35例),研究组采用低剂量采集模式,对照组采用传统采集模式,其余扫描参数完全相同,对两组患者所接受的辐射剂量和图像质量进行对比分析。结果：研究组和对照组的累积剂量(CD)值分别是(210.26...     

128排冠状动脉CTA图像质量与低剂量的研究分析

目的 探讨128排螺旋CT低剂量前门控冠状动脉CTA的图像质量.方法 研究对象随机分为2组,分别采用前门控(31例)和低剂量后门控(47例)扫描技术,扫描仪为西门子128排螺旋CT.前门控扫描的主要参数包括:管电压100 kV,管电流205 mAs,70% R-R间期扫描.低剂量后门控扫描的主要参数包括:100 kV,40%～70% R-R间期时管电流采用190 mAs,其余R-R间期时管电流采用19 mAs.螺距0.2～0.5.对每例冠状动脉3支主干:右冠状动脉(RCA)、左前降支(LAD)和左旋支(LCX)的图像质量进行4级评分,测量增强图像的信噪比(SNR),并记录每例患者接受的放射剂量.结果 前、后门控2组中的图像质量均没有明显差异.前门控组的平均放射剂量明显低于低剂量后门控组.结论 利用前门控冠状动脉CTA扫描可以在大幅度降低患者所受放射剂量的同时,保持良好的图像质量.     

64层螺旋CT冠状动脉成像低剂量技术的应用价值

目的 探讨低剂量技术在64层螺旋CT冠状动脉成像中的应用. 资料与方法 连续选取100例患者进行冠状动脉检查.将患者分为常规组(C组)和低剂量组(L组),每组50例.C组采用标准采集方法 ,L组采用低剂量采集方法 ,然后对C组和L组图像质量、噪声、容积CT剂量指数(CTDIvol)和有效剂量(ED)进行评估. 结果 C组和L组图像质量评分分别为(3.56±0.54)分和(3.62±0.57)分,图像噪声分别为27.54±4.52和27.30±6.15,两组间无显著差异(P>0.05).但C组和L组的CTDIvol分别为(87.91±8.38) mGy/cm和(43.11±4.38) mGy/cm,ED分别为(17.96±1.71) mSv和(8.75±0.83) mSv,L组的CTDIvol和ED均明显低于C组(P< 0.05). 结论 低剂量采集方法 既可明显降低受检者的射线剂量又能满足诊断需求.     

迭代重建算法在低剂量冠状动脉成像中的初步应用

目的 对比低剂量冠状动脉成像使用迭代重建算法(iDose)与标准剂量冠状动脉成像使用滤过反投影法(FBP)的剂量与图像质量.方法 采用256层螺旋CT,选取120例临床拟诊为冠心病的患者,对于心率≤65次/min的患者采用前瞻性门控扫描方式,心率＞65次/min的患者采用回顾性门控扫描方式.将120例随机分为低剂量组和常规剂量组.对比分析两种扫描方式下低剂量和常规剂量的图像质量及辐射剂量.低剂量组均使用迭代重建算法(iDose)行图像重建,常规剂量组均使用FBP行图像重建.将冠状动脉主要分支分为9个节段评价,采用4分法评价图像质量,图像质量、噪声和有效剂量(ED)测量记录用于图像评价.结果 回顾性门控扫描常规剂量组与低剂量组平均ED分别为8.29±1.22和4.29±1.22,低剂量组较常规剂量组剂量降低了49％(P＜0.01);前瞻性门控扫描常规剂量组与低剂量组平均ED分别为3.03±0.53和1.40 ±0.13,低剂量组较常规剂量组剂量降低了54％(P＜0.01);回顾性门控扫描方式和前瞻性门控扫描方式下常规剂量组和低剂量组图像的主观评分、图像信噪比、对比信噪比及降主动脉噪声差异均无统计学意义(P＞0.05).结论 使用iDose可以在保证图像质量的同时进一步降低辐射剂量.     

不同低剂量CT扫描对眼眶部外伤病变的诊断价值

目的 :探讨不同低剂量CT扫描对眼眶部外伤病变的诊断价值。方法 :对 14 8例眼眶部外伤患者分为 4组行不同低剂量 (10mA组 4 0例、2 0mA组 30例、30mA组 4 8例、5 0mA组 30例 )CT扫描 ,并对每例患者选取晶状体视神经层面常规剂量 (10 0mA)CT扫描 ,比较该层面二者的图像质量、眼眶部外伤病变的显示和患者辐射剂量。结果 :低剂量 (10mA、2 0mA)CT扫描图像质量以差的为主 ,不能显示球内小血肿。低剂量 (30mA、5 0mA)CT扫描图像质量以较好为主 ,对眼眶外伤病变的显示与常规剂量 (10 0mA)CT扫描相同。结论 :低剂量 (30mA)CT扫描可以用于诊断眼眶部外伤。     

低剂量双能量冠状动脉成像在心脏功能检查中的应用

目的 :探讨低剂量双能量冠状动脉成像在心脏功能检查中的可行性。方法 :收集60例低剂量双能量冠状动脉成像发现冠状动脉左前降支(LAD)狭窄患者,并行DSA检查,分析其左心室功能及心肌灌注改变。结果:60例LAD不同程度狭窄患者的左室舒张末期容积(EDV)、收缩末期容积(ESV)、射血分数(EF)、心肌质量(MM)比较差异均有统计学意义(均P0.05),每搏输出量(SV)、心输出量(CO)比较差异均无统计学意义(均P0.05)。左心室心肌灌注异常情况:正常组无灌注异常;轻度狭窄组2例,中度狭窄组11例,重度狭窄/闭塞组21例。结论:低剂量双能量冠状动脉成像可评估左心室功能、心肌灌注情况,有一定的临床价值。     

脑钠素与非ST段抬高型心肌梗死冠状动脉病变程度的关系

 目的 探讨血浆脑钠素(BNP)与非ST段抬高急性心肌梗死(NSTEMI)患者冠状动脉病变程度的关系.方法 研究入选NSTEMI患者81例,均在治疗前采血检查血浆BNP水平,根据BNP中位数将患者分为2组,高BNP组(BNP≥150 pg/ml)和低BNP组(BNP＜150 pg/ml).用Judking法对每位患者行冠状动脉造影术(CAG),将其分为正常组、A、B1、B2、C型病变组.结果 高BNP组较低BNP组患者冠脉血管病变较重的B、C型病变组人数多,分别为39例(48.5%)和16例(19.8%),差异有统计学意义(P＜0.05).结论 NSTEMI 患者冠脉病变程度严重者血浆BNP升高,提示血浆BNP是NSTEMI患者冠脉病变程度的重要预测指标.     

双源CT心脏“一站式”检查低剂量扫描方案在低心率患者中的应用

目的 探讨双源CT(dual-source CT,DSCT)前瞻性心电门控“一站式”低剂量扫描方案在低心率患者冠状动脉成像及左心室功能分析中的应用价值.方法 33例临床怀疑或确诊为冠心病的患者1周内同时行冠状动脉DSCT和超声心动图检查.入组条件:心律规则且心率≤70次/分.DSCT采用管电流调制,前瞻性心电触发序列扫描,扫描窗宽为30％～ 80％ R-R间期,全电流采集时相为70％ R-R间期,其余时相使用全电流的20％.冠状动脉依据美国心脏学会冠状动脉16分段法,图像质量用4级法进行评估,1～3级图像为可评估,能用于影像诊断,4级为不可评估.采用手动矫正Simpson法计算DSCT所测得的左心室射血分数(LVEF),并以超声心动图测得的LVEF值为对照进行配对t检验和Pearson相关性检验.结果 30例患者顺利完成检查及左心室功能分析,1例心脏扫描失败,2例左心室功能分析失败.平均辐射剂量为(3.08±0.40) mSv.共评价冠状动脉409段,其中可用于诊断的节段占96.82％.双侧配对t检验结果显示DSCT与超声心动图测得的LVEF值差别无统计学意义(P=0.14),且有很高的相关性(r=0.74).结论 DSCT前瞻性心电触发序列扫描低剂量“一站式”心脏检查方法可以用于低心率患者的冠状动脉成像和左心室功能分析.冠状动脉图像质量较好,左心室功能分析结果可靠,平均辐射剂量较低.     

老年患者择期冠状动脉介入治疗中低剂量比伐卢定安全性观察

目的 探讨老年患者择期经皮冠状动脉介入治疗(PCI)中应用低剂量比伐卢定的安全性.方法 连续选取年龄＞65岁冠心病患者162例,随机分为标准剂量组(n=80)和低剂量组(n=82).PCI术前两组患者接受静脉推注负荷剂量比伐卢定0.75 mg/kg,术中标准剂量组以1.75 mg· kg-1·h-1加术后0.2 mg· kg-1· h-1剂量持续给药2h,低剂量组以1.5mg·kg-1·h-1加术后0.15 mg·kg-1·h-1剂量持续给药2h.对比分析两组患者给药后5 min、30 min、手术终止时、术后1h活化凝血时间(ACT)值以及术后1个月内出血事件、心肌梗死、靶血管重建、支架内血栓、不明原因卒中发生率.结果 低剂量组给药后30 min、手术终止时、术后1 h ACT值与标准剂量组相比均明显降低,分别为(331.2±53.5)s对(383.5±74.7)s、(324.9±47.6)s对(371.3±65.4)s、(289.6±34.9)s对(314.8±43.1)s,P值均＜0.001.两组患者术后1个月内心肌梗死、一般出血事件发生率比较,差异均无统计学意义(P＞0.05),未发生大出血、靶血管重建、支架内血栓和不明原因卒中事件.结论 老年冠心病患者择期PCI术中应用低剂量比伐卢定抗凝,具有良好的治疗效果及安全性.     

双源CT低剂量适应性序列扫描对高心率冠状动脉成像的初步研究

目的 研究双源CT低剂量适应性序列扫描技术在高心率患者冠状动脉CTA的应用,并评价其图像质量.方法 将72例心率70次/min(bpm)以上行冠状动脉CTA检查的患者按扫描方式分为2组.A组40例行适应性序列扫描.B组32例行常规回顾性心电门控螺旋扫描.对2组扫描的冠状动脉分别做图像处理,应用秩和检验比较2组患者冠状动脉段图像质量总体评分,应用两独立样本t检验比较2组患者辐射剂量.结果 A组评价501段冠状动脉,B组评价400段冠状动脉.可评价的冠状动脉段图像质量评分平均秩次,A组为475.42,B组为420.41,2组间比较差异有统计学意义(Z=-3.509,P=0.000).平均有效剂量A组为(6.2±0.9)mSv,B组为(14.7 ±1.9)mSv,2组间差异有统计学意义(t=-27.011,P=0.000).结论 适应性序列扫描对高心率患者冠状动脉CTA检查具有可行性,该技术能显著降低辐射剂量而保证诊断所需图像质量.     

全下肢动脉血管造影技术的临床应用探讨

目的比较血管造影跟踪法(bolus chasing angiography,BCA)与传统法(static digital subtraction angiography,DSA)的技术特点。方法回顾性分析了我院61例全下肢动脉血管造影患者的造影技术参数,其中31例采用BCA、30例采用DSA血管造影技术。分别对完成造影时间、对比剂用量、图像质量、患者吸收辐射剂量(dose-area product,DAP)进行对照分析。结果2种造影技术对比显示:DSA的图像质量在显示胫腓血管上优于BCA,但是DAP值高,对比剂用量多以及检查时间长。经统计学处理,二者差异均具有显著性(P<0.00)。结论BCA与DSA相比具有造影时间短,对比剂量用量少,DAP低的特点,DSA局部观察血管情况较细致。因此,先行BCA筛查,然后针对病变加做局部DSA。     

A comparison of bolus chasing and static digital subtraction arteriography in peripheral vascular disease

The purpose of this study was to compare the techniques of bolus chasing angiography (BCA) and digital subtraction angiography (DSA). 75 patients with symptomatic atherosclerotic peripheral vascular disease were randomly assigned to have their lower limbs examined by BCA or DSA. Dose-area product (DAP), time of examination and dose of contrast medium were measured. Staff doses were measured with personal electronic dosemeters. Image quality was assessed from the laser printed images. DSA produced better images of vessels below the inguinal ligament, particularly the crural vessels (1/76 vs 17/74 non-diagnostic examinations, p < 0.00001) but at a higher DAP (median 53.8 Gy cm2 vs 18.9 Gy cm2, p < 0.01). Contrast medium dose was higher with BCA (29.8 gI2 vs 25.3 gI2, p < 0.01). Staff doses per unit patient dose were 2.3-3.3 times higher with BCA than DSA. Because of the poor long-term prognosis of patients with peripheral vascular disease, the improved image quality obtained by DSA justifies the increased radiation dose.     

The effect of equipment set up on patient radiation dose in conventional and CT angiography of the renal arteries

Patient radiation dose in angiography of the renal arteries was assessed and optimized after installing new radiological equipment. In three separate studies (n=50, 25 and 20) patient exposure was monitored in detail. For the first study default factory settings were used, for the second the number of digital subtraction angiography (DSA) images was halved and the X-ray beam filtering during fluoroscopy was increased, and for the third study filtering during DSA was increased as well. Standard projections were derived and used in Monte Carlo simulations to derive dose conversion coefficients to calculate effective dose from the dose-area product (DAP). Dose conversion coefficients were also calculated for CT angiography (CTA). Using default factory settings on the new angiography system, DAP, number of images and effective dose were much higher than on the replaced unit. For the studies given above, DAP was reduced from 144 Gy cm(2) to 65 Gy cm(2) to 32 Gy cm(2), and effective dose from 22 mSv to 11 mSv to 9.1 mSv, respectively. Effective dose due to CTA was 5.2 mSv. It is concluded that modern angiography systems, resulting in high customer satisfaction, may readily cause much higher patient exposure than older systems. These doses may also be much higher than necessary. Optimization before putting such systems into use is absolutely essential. Internationally accepted recommendations for image quality and technique factors in angiography would be of great help.     

肺动脉CT三维血管成像低剂量扫描的应用

目的 探索肺动脉三维血管成像多层螺旋CT低剂量扫描的可行性,以及肺动脉容积三维处理(VR)图像的质量与平扫SD值的关系.方法 选取行肺动脉CT检查的受检者87人.选取志愿者63人为低剂量组,其余24人采用常规剂量扫描作为常规组.两者平扫均采用常规剂量150 mAs,低剂量肺动脉增强扫描采用60 mAs.图像进行VR后处理后,按A、B、C 3个等级进行评定,两组VR图像进行质量等级比较.低剂量组平扫图像测量CT值的标准差SD值,与增强的VR图像质量等级关系进行受试者操作特性曲线(ROC)分析.结果 常规剂量组VR图像等级为A级的达到100%,在低剂量组VR图像等级为A级的达到85.7%.平扫SD值与肺动脉VR图像的质量相关性分析,ROC曲线下面积为0.906.结论 肺动脉三维血管成像的低剂量扫描切实可行.     

肺动脉CT三维血管成像低剂量扫描的应用

目的 探索肺动脉三维血管成像多层螺旋CT低剂量扫描的可行性,以及肺动脉容积三维处理(VR)图像的质量与平扫SD值的关系.方法 选取行肺动脉CT检查的受检者87人.选取志愿者63人为低剂量组,其余24人采用常规剂量扫描作为常规组.两者平扫均采用常规剂量150 mAs,低剂量肺动脉增强扫描采用60 mAs.图像进行VR后处理后,按A、B、C 3个等级进行评定,两组VR图像进行质量等级比较.低剂量组平扫图像测量CT值的标准差SD值,与增强的VR图像质量等级关系进行受试者操作特性曲线(ROC)分析.结果 常规剂量组VR图像等级为A级的达到100%,在低剂量组VR图像等级为A级的达到85.7%.平扫SD值与肺动脉VR图像的质量相关性分析,ROC曲线下面积为0.906.结论 肺动脉三维血管成像的低剂量扫描切实可行.     

Radiation dose and image quality of X-ray volume imaging systems: cone-beam computed tomography, digital subtraction angiography and digital fluoroscopy

Objective

Radiation dose and image quality estimation of three X-ray volume imaging (XVI) systems.

Methods

A total of 126 patients were examined using three XVI systems (groups 1–3) and their data were retrospectively analysed from 2007 to 2012. Each group consisted of 42 patients and each patient was examined using cone-beam computed tomography (CBCT), digital subtraction angiography (DSA) and digital fluoroscopy (DF). Dose parameters such as dose–area product (DAP), skin entry dose (SED) and image quality parameters such as Hounsfield unit (HU), noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were estimated and compared using appropriate statistical tests.

Results

Mean DAP and SED were lower in recent XVI than its previous counterparts in CBCT, DSA and DF. HU of all measured locations was non-significant between the groups except the hepatic artery. Noise showed significant difference among groups (P?<?0.05). Regarding CNR and SNR, the recent XVI showed a higher and significant difference compared to its previous versions. Qualitatively, CBCT showed significance between versions unlike the DSA and DF which showed non-significance.

Conclusion

A reduction of radiation dose was obtained for the recent-generation XVI system in CBCT, DSA and DF. Image noise was significantly lower; SNR and CNR were higher than in previous versions. The technological advancements and the reduction in the number of frames led to a significant dose reduction and improved image quality with the recent-generation XVI system.

Key Points

? X-ray volume imaging (XVI) systems are increasingly used for interventional radiological procedures. ? More modern XVI systems use lower radiation doses compared with earlier counterparts. ? Furthermore more modern XVI systems provide higher image quality. ? Technological advances reduce radiation dose and improve image quality.     

肺动脉CT三维血管成像低剂量扫描的应用

目的 探索肺动脉三维血管成像多层螺旋CT低剂量扫描的可行性,以及肺动脉容积三维处理(VR)图像的质量与平扫SD值的关系。方法 选取行肺动脉CT检查的受检者87人。选取志愿者63人为低剂量组,其余24人采用常规剂量扫描作为常规组。两者平扫均采用常规剂量150 mAs,低剂量肺动脉增强扫描采用60 mAs。图像进行VR后处理后,按A、B、C 3个等级进行评定,两组VR图像进行质量等级比较。低剂量组平扫图像测量CT值的标准差SD值, 与增强的VR图像质量等级关系进行受试者操作特性曲线(ROC)分析。结果 常规剂量组VR图像等级为A级的达到100%,在低剂量组VR图像等级为A级的达到85.7%。平扫SD值与肺动脉VR图像的质量相关性分析,ROC曲线下面积为0.906.结论 肺动脉三维血管成像的低剂量扫描切实可行。     

XperSwing技术与常规冠状动脉造影的辐射剂量对比模体研究

目的 研究常规冠状动脉造影(CCA)与采用XperSwing技术冠状动脉造影的辐射剂量差异.方法 应用中国人仿真胸部体模,采用XperSwing和CCA2种检查技术,将热释光个人剂量计(TLD)布放于仿真胸部体模的主要组织器官,测量各组织器官的吸收剂量并读取设备的剂量面积乘积(DAP)值.实际测量有效剂量等于组织器官吸收剂量乘以相应组织权重因子后的总和;设备读取的有效剂量等于DAP乘以转换因子(0.185 mSv/ Gy·cm2).结果 采用XperSwing技术造影的组织器官平均吸收剂量低于CCA检查;CCA和XperSwing技术造影的设备读取平均有效剂量分别为3.88和3.13 mSv,低于实际测量的平均有效剂量(5.57和4.94 mSv).结论 采用XperSwing技术的辐射剂量低于CCA,设备读取的有效剂量有可能低估了患者实际接受的有效剂量水平.     

桡动脉与股动脉入路模拟冠脉造影术患者和术者辐射剂量比较

 目的 比较经桡动脉与经股动脉途径行冠脉造影术中患者及术者的辐射剂量。方法 采用同一拟人体模模拟临床条件下的冠脉造影。根据不同造影入路(均为右侧入路),实验分为经股动脉行冠脉造影组(transfemoral intervention ,TFI)和经桡动脉行冠脉造影组(transradial intervention,TRI),根据不同测量位置和不同辐射防护措施,TFI组进一步分为TFI1-TFI4四个亚组,TRI组进一步分为TRI1-TRI8八个亚组。使用皮肤辐射剂量仪和造影机随机配备的射线剂量仪(DAP和AK)分别记录术者和患者的辐射剂量,使用机器预设程序自动调节造影体位并控制透视及造影时间,每组数据重复测量10次取均值进行比较。结果 TRI组总剂量均值、透视累计剂量均值、造影累计剂量均值较TFI组均明显增加。造影过程7个体位中,DAP、AK值最大的三个体位均为左前斜体位。经桡动脉操作时,使用桡动脉专用护具的各亚组,其术者的辐射剂量均明显低于未使用护具的亚组。结论 与TFI相比,TRI时术者手部、胸部辐射剂量明显高于前者,而胸部辐射剂量的差异在左前斜体位时最为显著,其他体位并不明显;无论何种入路行冠脉造影,患者辐射剂量在左前斜体位时最高。因此术者在操作过程中应该合理使用造影体位,减少不必要的辐射。桡动脉专用护具配合常规防护设备共同使用可以大大减少经桡动脉操作时术者辐射剂量,值得推广。     

Imaging guidance with C-arm CT: prospective evaluation of its impact on patient radiation exposure during transhepatic arterial chemoembolization

Purpose

To prospectively evaluate the impact of C-arm CT on radiation exposure to hepatocellular carcinoma (HCC) patients treated by chemoembolization.

Materials and Methods

Patients with HCC (N = 87) underwent digital subtraction angiography (DSA; control group) or combined C-arm CT/DSA (test group) for chemoembolization. Dose-area product (DAP) and cumulative dose (CD) were measured for guidance and treatment verification. Contrast agent volume and C-arm CT utility were also measured.

Results

The marginal DAP increase in the test group was offset by a substantial (50%) decrease in CD from DSA. Use of C-arm CT allowed reduction of DAP and CD from DSA imaging (P = .007 and P = .017). Experienced operators were more efficient in substituting C-arm CT for DSA, resulting in a negligible increase (7.5%) in total DAP for guidance, compared with an increase of 34% for all operators (P = .03). For treatment verification, DAP from C-arm CT exceeded that from DSA, approaching that of conventional CT. The test group used less contrast medium (P = .001), and C-arm CT provided critical or supplemental information in 20% and 17% of patients, respectively.

Conclusions

Routine use of C-arm CT can increase stochastic risk (DAP) but decrease deterministic risk (CD) from DSA. However, the increase in DAP is operator-dependent, thus, with experience, it can be reduced to under 10%. C-arm CT provides information not provided by DSA in 33% of patients, while decreasing the use of iodinated contrast medium. As with all radiation-emitting modalities, C-arm CT should be used judiciously.