320层容积CT冠状动脉血管造影的护理

目的:探讨320层容积CT冠状动脉造影检查中相关的护理因素。方法:对620例(男380例,女240例,平均年龄58.4±9.2岁)临床怀疑冠心病行320层CT冠状动脉造影检查的患者在检查前、检查过程中及检查后采用有效的护理流程进行严格的护理,并对相关图像资料进行回顾性分析。结果:620例患者中605例(97.5%)的图像能满足影像学评价。在2480支冠状动脉分支中1级血管分支共1709支(68.9%),满足诊断要求的血管分支共2390支(96.4%)。结论:严格和有效的护理流程是320层容积CT冠脉造影检查成功和提高图像质量的重要保证。     

Evaluation of 320-row area detector computed tomography (ADCT) coronary angiography for patients with atrial fibrillation

The aim of this study was to evaluate 320-row area detector CT (ADCT) for patients with atrial fibrillation (Af) based on simulated exposure using electrocardiogram RR intervals and comparison with the findings of coronary CT angiography (CCTA) using 64-row multi slice CT (MSCT). The probability of including RR intervals of 900 ms or more was calculated when the acquisition time was varied from 1 to 4 beats. Overall, 51 patients with Af who underwent CCTA were examined. The exposure time for CCTA, the total dose length product (DLP) for the examination, and the image quality (scored 0 to 3: poor to excellent) were compared between ADCT and MSCT. The probability of including RR intervals of 900 ms or more was highly significantly increased at 3 beats of acquisition time. The exposure time using ADCT was reduced by 75% compared with MSCT (ADCT/MSCT: 2.8/11.3 s), and the total DLP was reduced by 40% (ADCT/MSCT: 1398/2277 mGy·cm). Moreover, ADCT provided diagnosable images in all cases, and the mean image quality score for ADCT was significantly higher than that for MSCT (ADCT/MSCT: 2.8/2.4). Thus, 320-row ADCT at 3 beats of acquisition time can provide CCTA images of acceptable quality for patients with Af.     

Minimizing the acquisition phase in coronary CT angiography using the second generation 320-row CT

Purpose

We aimed to compare the radiation dose and image quality of a minimal phase window centered at 77 % compared with a wide phase window in coronary CT angiography using the second-generation 320-row CT.

Materials and methods

Eighty patients with heart rate ≤75 bpm were retrospectively included. The first 40 patients underwent scanning with a wide phase window (65–85 %), while the last 40 patients underwent scanning with a minimal phase window centered at 77 %. Subjective image quality was graded using a 4-point scale (4 = excellent). Image noise and contrast-to-noise ratio at the proximal segments were also analyzed. The mean effective dose was derived from the dose length product multiplied by a chest conversion coefficient (κ = 0.014 mSv mGy^?1 cm^?1).

Results

Minimal phase window scanning centered at 77 % reduced the radiation dose by 30 % compared with wide phase window scanning (1.7 vs 2.4 mSv, p = 0.0009). The subjective image quality showed no significant difference (3.75 vs 3.76, p = 0.77). No significant difference was observed in the image noise, CT number, and contrast-to-noise ratio.

Conclusions

Radiation dose could be reduced while maintaining image quality by use of a minimal phase window centered at 77 % compared with a wide phase window in coronary CT angiography using the second generation 320-row CT.     

全部主动脉和冠状动脉的前瞻性心电门控320排CT血管成像

目的探讨采用前瞻性心电门控大范围扫描方案进行全部主动脉和冠状动脉CT血管成像的可行性。方法连续61例疑为急性主动脉疾病的病人,采用前瞻性心电门控的大范围CT扫描方案在无心率控制条件下进行全部主动脉的CT血管成像。每个心动周期内,曝光窗设定为R-R间期的40%～50%(HR≥70次/min)或R-R间期的70%～80%(HR<70次/min)。评价升主动脉、主动脉瓣和冠状动脉的运动伪影情况来衡量影像质量。在主动脉的不同水平测量平均CT值。记录辐射剂量和所用的对比剂体积。结果所有的检查均顺利完成。升主动脉、主动脉瓣(100%)和冠状动脉(94.4%)的影像质量是可以接受的,平均辐射剂量为(18.42±5.02)mSv。61例病人中,14例诊断为主动脉瘤,35例诊断为主动脉夹层或壁内血肿。12例病人发现冠状动脉狭窄。结论对于患主动脉疾病的病人,采用前瞻性心电门控的大范围扫描方案进行整个主动脉的CT血管成像,能够在低辐射剂量条件下获得冠状动脉和主动脉瓣的额外信息。     

320排CT诊断飞行员壁冠状动脉一例

一、临床资料 患者男性,36岁,直-9飞行员,飞行时间2800 h.患者于2003年健康体检心电图检查示T波改变,心得安试验阳性,但无任何自觉症状.结论:飞行合格.     

动态容积320排冠状动脉CT血管成像诊断冠状动脉疾病的意义

目的：研究320排动态容积冠状动脉CT成像（CCTA）诊断冠状动脉疾病（CAD）的可行性。方法：5961例临床诊断CAD的患者进行CCTA检查,其中186例接受常规X线冠状动脉造影术（CAG）,对照分析其检查结果。1490例接受CCTA检查的健康查体者作为对照。结果：成像质量均在I～III级,无呼吸伪影图像。在186例CAD患者中,CCTA诊断冠状动脉狭窄（狭窄度≥50％）的敏感性为96．72％,特异性98．95％,阳性预测值95．16％,阴性预测值99．30％,准确度98．56％。结论：320排动态容积CT冠状动脉成像图像清晰,对诊断CAD具有重要的临床价值。     

Computed tomography angiography of carotid and coronary artery via a single-bolus injection protocol: a feasibility study using 320-row multidetector CT

Objectives

To investigate the feasibility of using a single-dose injection protocol in CT angiography (CTA) of the carotid and coronary artery with 320-row multidetector CT.

Methods

A total of 82 consecutive patients with suspected carotid artery disease underwent an original CTA protocol aiming at capturing the extra-cranial carotid arteries and coronary arteries simultaneously using 320-row MDCT. The image quality, attenuation, and CNRs of the carotid and coronary arteries were assessed. The lag time (between two separated volumetric acquisitions) was compared between patients with and without cardiac venous opacification (CVO). The contrast medium volume and radiation dose were recorded.

Results

The image quality was 99.4 % diagnostic in carotid and 86.9 % in coronary artery segments. The mean attenuation of carotid and coronary arteries ranged from 462.2 Hu to 533.7 Hu, 415.9 Hu to 454.7 Hu respectively. The mean CNR of the carotid and coronary artery ranged from 15.8 to 18.9 and 17.7 to 20.4 respectively. The lag time in patients with and without CVO was 5.75?±?1.64 s vs. 4.21?±?1.14 s (p?<?0.05). The mean radiation dose was 6.6?±?4.1 mSv.The mean contrast media volume was 71.9?±?9.1 ml.

Conclusions

The carotid and coronary artery can be imaged simultaneously via our original single-dose injection CTA protocol using 320-row CT with adequate image quality.

Key Points

? Carotid and coronary 320-row CTA can be achieved in a single-dose injection. ? Longer coverage was achieved with two or more volumes using 320-row CT. ? The single-dose protocol allows a reduced contrast agent dose of about 72 ml.     

320-row CT coronary angiography predicts freedom from revascularisation and acts as a gatekeeper to defer invasive angiography in stable coronary artery disease: a fractional flow reserve-correlated study

Objectives

To determine the accuracy of 320-row multidetector coronary computed tomography angiography (M320-CCTA) to detect functional stenoses using fractional flow reserve (FFR) as the reference standard and to predict revascularisation in stable coronary artery disease.

Methods

One hundred and fifteen patients (230 vessels) underwent M320-CCTA and FFR assessment and were followed for 18 months. Diameter stenosis on invasive angiography (ICA) and M320-CCTA were assessed by consensus by two observers and significant stenosis was defined as ≥50 %. FFR ≤0.8 indicated functionally significant stenoses.

Results

M320-CCTA had 94 % sensitivity and 94 % negative predictive value (NPV) for FFR ≤0.8. Overall accuracy was 70 %, specificity 54 % and positive predictive value 65 %. On receiver operating characteristic (ROC) curve analysis, the area under the curve (AUC) for CCTA to predict FFR ≤0.8 was 0.74 which was comparable with ICA. The absence of a significant stenosis on M320-CCTA was associated with a 6 % revascularisation rate. M320-CCTA predicted revascularisation with an AUC of 0.71 which was comparable with ICA.

Conclusions

M320-CCTA has excellent sensitivity and NPV for functional stenoses and therefore may act as an effective gatekeeper to defer ICA and revascularisation. Like ICA, M320-CCTA lacks specificity for functional stenoses and only has moderate accuracy to predict the need for revascularisation.

Key Points

? Important information about the heart is provided by 320-row multidetector CT coronary angiography (M320-CCTA). ? M320-CCTA accurately detects and excludes functional stenoses determined by fractional flow reserve (FFR). ? Non-significant stenoses on M320-CCTA associated with fewer cardiac events and less revascularisation. ? M320-CCTA may act as a gatekeeper for invasive angiography and inappropriate revascularisation. ? Like ICA, M320-CCTA only has moderate accuracy to predict vessels requiring revascularisation.     

眼动脉的320排容积CT血管成像研究

目的 探讨眼动脉的解剖及常见变异的CTA显示,评价3种CTA重组方法之间显示眼动脉各段的差异.方法 常规眼眶或颅脑增强扫描的40例患者进行了评价,利用Toshiba Aquilion one 320排容积CT容积扫描所得的容积数据进行MIP、VR和MPR重组,观察眼动脉的起源、形态特点、分支以及变异情况.结果 2支异常起源眼动脉来自脑膜中动脉.MPR、MIP和VR 3组图像之间显示眼动脉起源部位的能力近似,均能较好地显示眼动脉根部与颈内动脉之间的关系.眼动脉各段显示:眼动脉颅内段短肢部、角"a"部、长肢部和角"b"部,均可在CTA上显示;眼动脉神经管段显示为直线结构的有19/78支(24.4%),有59/78支(75.6%)显示为迂曲结构;眼动脉眶内段:横过视神经走行至视神经内侧,68/78(87%)在视神经上方横过,10/78(13%)位于视神经下方.眼动脉分支:CTA对眼动脉很多分支不能很好地显示,眼动脉分支变异极大,MPR可以显示部分分支血管,VR及MIP均显示不满意.结论 320排容积CT容积扫描所得数据CTA重组图像可以较好地显示眼动脉眼动脉的起源、形态特点、分支以及变异情况.     

Influence of hemodynamic parameters on coronary artery attenuation with 320-detector coronary CT angiography

Objectives

To investigate the relationship between cardiac output, end diastolic volume and the contrast enhancement in coronary CT angiography using 320-detector CT.

Materials and methods

A total of 38 patients underwent coronary CT angiography by using a 320-detector CT scanner (detector configuration, 320 × 0.5 mm). The attenuation value of the ascending aorta at the level of the orifice of the left main trunk was measured. The cardiac output (CO), end diastolic volume (EDV) and stroke volume (SV) were measured by echocardiography. The EDV was normalized to the body surface area (BSA). The total blood volume injected from the left ventricle from the beginning of the contrast agent injection to the time of image acquisition was determined to be the total injected blood volume (TIV), which is a product of SV and the number of heart beats from the initiation of contrast agent injection to the scan.

Results

There was a negative correlation between the attenuation of the ascending aorta and CO (r = −0.44, P = 0.0053). However, the negative correlation between the attenuation of the ascending aorta and TIV was stronger (r = −0.52, P = 0.0007). There was a negative correlation between the attenuation of the ascending aorta and EDV/BSA (r = −0.45, P = 0.0039).

Conclusion

In 320-detector CT, contrast enhancement in CCTA with a lesser amount of contrast medium decreases when cardiac output is high. Patients with larger EDV/BSA may also show decreased attenuation.     

64排螺旋CT冠状动脉成像在冠心病诊断中的临床应用

目的探讨64排螺旋CT冠状动脉成像CTA在冠心病诊断中的应用。方法对86例应用64排螺旋CT扫描的冠状动脉图像资料进行回顾性分析。结果 86例冠脉CTA中有81例检查成功,冠状动脉主要分支显示良好,达到诊断要求。发现冠状动脉病变59例,其中冠状动脉狭窄45例;5例为冠状动脉支架置入术后;2例冠脉搭桥术后;8例检出心肌桥;3例冠状动脉发育异常。结论 CTA可清晰显示冠状动脉狭窄,可作为冠心病的一种可靠的无创筛选检查方法。     

320排容积CT低剂量冠状动脉成像在冠心病高危人群中的应用

目的 探讨320排容积CT冠状动脉造影(VCTA)在冠心病高危人群中的应用价值.方法 对近期300例有冠心病高危因素的患者,应用320排动态容积CT前瞻性心电门控全心容积扫描检查,其中43例有冠状动脉造影作为对照,并对本组所有显示的冠状动脉主干及其主要分支进行分级评价,对所有病例进行辐射剂量统计.结果本组300例发现病变163例,单支病变112例,多支病变51例;其中狭窄度≥70% 59例(36.2%),＜70% 104例(63.8%).320排容积CT冠状动脉成像诊断≥70%冠状动脉狭窄的敏感性、特异性、阳性预测值、阴性预测值分别为96.6%,97.9%,92.3%,99.1%.冠状动脉成像质量1级256例(85.3%),2级41例(13.7%),3级3例(1.0%).使用的平均有效剂量为(3.06±0.39)mSv.结论 320排动态容积CT冠状动脉成像速度快,诊断冠状动脉狭窄准确性高,图像质量好,辐射剂量低,是冠心病高危人群筛查的首选检查.     

64层螺旋CT冠状动脉成像诊断冠状动脉疾病的临床应用

目的：探讨64层螺旋CT冠状动脉成像（64SCTCA）诊断冠状动脉中、重度狭窄（管腔直径≥50%）的临床应用价值。方法：收集140例患者64SCTCA的完整资料,依据AHA15段分段法,对有效节段进行评价,并以近期实施的选择性X线冠状动脉造影（CAG）结果为＂金标准＂进行对照分析,了解64SCTCA诊断冠状动脉中、重度狭窄的敏感性、特异性和准确度。结果：所有病例可用于评估的1360节段冠状动脉中,共显示病变284节段,其中272节段得到CAG证实,18节段64SCTCA显示中度狭窄而CAG显示仅为轻度狭窄,6节段64SCTCA显示正常或轻度狭窄而CAG显示中度狭窄,23节段重和中度狭窄的评估两者结果不一致,64SCTCA诊断冠状动脉中、重狭窄的敏感性为95.77%、特异性99.07%、准确度为98.68%。结论：64SCTCA是一种安全可靠且准确有效的冠状动脉检查方法,可作为临床进行CAG检查前的有效筛选手段。     

Estimation of radiation dose and image quality of coronary 320-row area detector CT angiography by optimal prospective ECG-gated protocols for different heart rate

The purpose of this study is to estimate radiation dose and image quality of ECG-gated coronary 320-area detector CT (ADCT) angiography which was acquired using the protocols that were considered as optimal methods for different heart rates (HR) in 1031 consecutive patients (M/F=580/451, 65 ± 12 yr) without arrhythmias. We set up 5 protocols for 320-ADCT based on the relationship among heart rates, temporal resolution, gantry rotation speed, optimal reconstruction phase and slow filling phase on 64-multidetector-row computed tomography (MDCT), ie, 1) mid-diastolic (75% of RR) 1 beat scan (MD 1 beat, N=761(73.8%)) for HR ≤ 60, 2) mid-diastolic (75% of RR) 2 beat scan (MD 2 beat, N=135) for 61 ≤ HR ≤ 65, 3) end-systolic and mid-diastolic (37-80% of RR) 2 beat scan (ES-MD 2 beat, N=92) for 66 ≤ HR ≤ 75, 4) end-systolic (R+280-430 ms) 2 beat scan (ES 2 beat, N=21) for 76 ≤ HR ≤ 80, and 5) end-systolic (R+250-400 ms) 3 beat scan (ES 3 beat, N=22) for 81 ≤ HR ≤ 105. Image quality was classified into 3 categories (excellent (3 points), acceptable (2 points), and unacceptable (1 point)). Scanning time, DLP.e and image quality score were 1.4 ± 0.1 s, 220 ± 59 mGy·cm, 3.0 ± 0.2 points in MD 1 beat, 2.2 ± 0.2 s, 434 ± 118 mGy·cm, 2.9 ± 0.3 points in MD 2 beat, 2.1 ± 0.2 s, 729 ± 229 mGy·cm, 2.7 ± 0.5 points in ES-MD 2 beat, 1.9 ± 0.1 s, 432 ± 148 mGy·cm, 2.2 ± 0.6 points in ES 2 beat, and 2.4 ± 0.2 s, 669 ± 152 mGy·cm, 2.3 ± 0.6 points in ES 3 beat respectively. In conclusion, the prospective ECG-gated scan protocol for coronary 320-ADCT angiography in any HR group was considered reasonable and proper for image quality and radiation dose.     

Effect of saline flush on enhancement of proximal and distal segments using 320-row coronary CT angiography

Objective

To investigate the effect of saline flush on coronary CT angiography of proximal, middle, and distal coronary artery segments, using 320-row CT, and to compare two injection duration protocols as to amount of contrast in the right heart chambers.

Methods

This retrospective study was approved by the local ethics committee, and the requirement for informed consent to participate in this study was waived. The final study group included 108 patients who underwent coronary CT angiography. The first 36 patients received contrast medium without saline flush (group 1); the next 36 patients received contrast medium for 14 s and saline flush (group 2); the last 36 patients received contrast medium for 12 s and saline flush (group 3). The CT number, noise, contrast-to-noise ratio (CNR), and number of segments with a CT number greater than 325 Hounsfield units (HU) were recorded for proximal, middle, and distal segments.

Results

The CT numbers and the CNR in groups 2 and 3 were significantly higher than that in group 1 (p < 0.005); the difference between groups 2 and 3 was not significant. The proportion of segments greater than 325 HU improved with saline flush (p < 0.05), with a larger improvement in the distal segments.

Conclusions

Saline flush improves enhancement and CNR of coronary arteries, particularly of distal segments, in coronary CT angiography using 320-row CT. An average contrast medium injection of 44 mL was feasible using a saline flush.     

320排容积CT冠状动脉血管成像在心律失常患者的应用

目的 评价320排CT容积扫描在心律失常(房颤和室性早搏)患者冠状动脉CT血管成像(CTCA)的可行性及其图像质量.方法 31例持续房颤和8例室性早搏患者.经320排CTCA检查.由2名有经验的放射科医师对CT图像质量(4级评分)进行评价,分析图像质量与患者的辐射剂量.2名评价者之间的一致性采用Kappa检验.结果 31例持续房颤和8例室性早搏患者中可评估的冠状动脉血管510段,其中496段(97.2％)达到诊断要求.患者的平均辐射剂量为(12.7±4.8)mSv.2名评价者对冠状动脉评分的一致性较好(Kappa=0.72).结论 房颤和室性早搏患者的CTCA检查具有可行性,心律失常患者可以不作为检查的禁忌证,但仍须进一步降低辐射剂量.     

Technical note: Electrocardiogram electrode repositioning for 320-row coronary CT angiography in patients with regular and recurrent premature ventricular contractions

Arrhythmias can compromise image quality and increase radiation exposure during coronary CT angiography (CTA). However, premature ventricular contractions (PVCs) can occur in a predictable recurrent and regular pattern (ie, bigeminy, trigeminy, quadrigeminy) with post-PVC compensatory pauses. Electrocardiographic (ECG) electrode repositioning can achieve relative amplification of the R waves of PVCs compared with R waves of sinus beats. This technical note describes how simple ECG electrode repositioning, combined with an absolute-delay strategy, facilitated selective R waves of PVC ECG triggering of image acquisition in 6 patients with PVC bigeminy or quadrigeminy at the time of 320-row coronary CTA. All 6 studies were single heartbeat acquisition scans with excellent image quality and a median effective radiation dose of 2.9 mSv (interquartile range, 2.1–3.8 mSv). Standard ECG electrode positions used for 2 patients with PVC bigeminy undergoing coronary CTA were associated with an acquisition over 2 heartbeats and effective radiation doses of 6.8 and 10.3 mSv, respectively. In conclusion, ECG electrode repositioning combined with an absolute-delay strategy for regularly recurring PVCs, such as ventricular bigeminy, facilitates high image quality and lower radiation dose during coronary CTA. This simple and straightforward technique can be considered for all patients with regular and recurrent PVCs undergoing coronary CTA.     

Feasible scan timing for 320-row coronary CT angiography generated by the time to peak in the ascending aorta

PurposeA 320-row CT scanner can briefly scan the entire heart. Therefore, the feasible scan timing is required. The aim of this study was to propose a refined method for feasible scan timing for coronary CT angiography (CCTA) using a time-density curve of the ascending aorta (AAo).MethodsOne-hundred and twenty-nine patients were prospectively enrolled. All patients were performed test-bolus method. For the initial 65 patients, the scan timing was determined as a 3.0 s delay at the peak time in the AAo, which was defined as the conventional protocol (COV-P). For the next 64 patients, a scan timing of 1.0, 3.0, or 5.0 s delay was determined according to the interval from the contrast media arrival to peak time in the AAo, which was defined as the arrival to peak protocol (AP-P). The optimal scan timing was identified by the measurement of CT number in the left atrium, left ventricle, AAo, and descending aorta. The coronary enhancement and heterogeneity were compared between the two protocols.ResultsThe optimal scan timing was significantly higher in the AP-P than in the COV-P (85.9% vs. 61.5%, p = 0.0017). The CT number in the left circumflex artery (LCX) was significantly higher in the AP-P than the COV-P (344.5 Hounsfield units vs. 316.3 Hounsfield units, p = 0.0484). The heterogeneous index of the LCX was significantly greater for the COV-P than the AP-P (−36.8 vs. –25.8, p = 0.0028).ConclusionsThe AP-P can be used to determine the optimal scan timing for CCTA and contributes to stable coronary enhancement.