Truncus arteriosus:Diagnosis with dual-source computed tomography angiography and low radiation dose

Truncus arteriosus is an uncommon congenital cardiac abnormality which is characterized by a single arterial trunk origin from the heart that supplies both the systemic,pulmonary and coronary circulation.We present a preterm newborn female patient with type 2 truncusarteriosus,left superior vena cava and aberrant subclavian artery diagnosed with low dose dual-source cardiac computed tomography(CT).We discuss that low dose dual-source cardiac CT has more advantages than other imaging methods and it is an important modality for assessment of patients with conotruncal anomalies such as truncusarteriosus.

Feasibility and Diagnostic Accuracy for Assessment of Coronary Artery Stenosis of Prospectively Electrocardiogram-gated High-pitch Spiral Acquisition Mode Dual-source CT Coronary Angiography in Patients with Relatively Higher Heart Rates: in Comparison wit

Objective To prospectively investigate the diagnostic accuracy for coronary artery stenosis of prospectively electrocardiogram-triggered spiral acquisition mode (high pitch mode) dual-source computed tomography coronary angiography (CTCA) in patients with relatively higher heart rates (HR) compared with catheter coronary angiography (CCA). Methods Forty-seven consecutive patients with relatively higher HR (>65 and <100 bpm) (20 male, 27 female; age 55±10 years) who both underwent dual-source CTCA and CCA were prospectively included in this study. All patients were performed CTCA using high pitch mode setting at 20%-30% of the R-R interval for the image acquisition. All coronary segments were evaluated by two blinded and independent observers with regard to image quality on a three-point scale (1: excellent to 3: non-diagnostic) and for the presence of significant coronary stenoses (defined as diameter narrowing exceeding 50%). Considered CCA as the standard of reference, the sensitivity, specificity, positive predictive value and negative predictive value were calculated. Radiation dose values were calculated using the dose-length product. Results Image quality was rated as being score 1 in 92.4% of segments, score 2 in 6.1% of segmentsand score 3 in 1.5% of segments. The average image quality score per segment was 1.064±0.306. The HR variability of patients with image score 1, 2 and 3 were 2.29±1.06 bpm, 5.17±1.37 bpm, 8.88±1.53 bpm, respectively. The average HR variability of patients with different image scores were significantly different (F=170.402, P=0.001). The sensitivity, specificity, positive and negative predictive values were 92.6%, 97.0%, 87.6%, 98.3%, respectively, per segment and 90.0%, 95.2%, 85.3%, 96.9%, respectively, per vessel and 100%, 63.6%, 90.0%, 100%, respectively, per patient. The effective radiation dose was on average 0.86±0.16 mSv. Conclusion In patients with HR more than 65 bpm and below 100 bpm without cardiac arrhythmia, the prospectively electrocardiogram-gated high-pitch spiral acquisition mode with image acquired timing set at 20%-30% of the R-R interval provides a high diagnostic accuracy for the assessment of coronary stenoses combined with a 1.5% of non-diagnostic coronary segments and a radiation dose below 1 mSv.

Intravenous Contrast Material Administration at High-pitch Dual-source CT Coronary Angiography: Bolus-tracking Technique with Shortened Time of Respiratory Instruction Versus Test Bolus Technique

Objective To investigate the feasibility of acquiring the similar homogeneous enhancement using bolus-tracking techniques with shortened respiratory time in prospectively electrocardiogram-gated high-pitch spiral acquisition mode (Flash mode) coronary computed tomography angiography (CCTA) compared with test bolus technique. Methods One hundred and eighty-four consecutive patients with mean heart rate ≤65 beats per minute undergoing CCTA were prospectively included in this study. The patients were randomly divided into two groups. Patients in the group A (n=92) instructed to shorten respiratory time received CCTA using bolus-tracking technique with high-pitch spiral acquisition mode (Flash mode), while those in the group B (n=92) underwent CCTA with test bolus technique. The attenuation in the ascending aorta, image noise, contrast-to-noise ratio and radiation doses of the two groups were assessed. Results There were no significant differences in the mean attenuation values in the ascending aorta (483.18±59.07 HU vs. 498.7±83.51 HU, P=0.183), image noise (21.4±4.5 HU vs. 20.9±4.3 HU, P=0.414), contrast-to-noise ratio (12.1±4.2 vs. 13.8±5.1, P=0.31) between the groups A and B. There were no significant differences in the radiation dose of dynamic monitoring scans (0.056±0.026 mSv vs. 0.062±0.018 mSv, P=0.068) and radiation dose of angiography (0.94±0.07 mSv vs. 0.96±0.15 mSv,P=0.926) between the two groups, while 15 mL less contrast material volume was administered in the group A than the group B. Conclusion Bolus-tracking technique with shortened time of respiratory in Flash mode of dual-source CT yields the similar homogeneous enhancement with less contrast material in comparison to the test bolus technique.

Computed tomography angiography-guided percutaneous coronary intervention in chronic total occlusion

Objective： The aim of this study is to investigate if dual-source computed tomography （DSCT） could guide the percutaneous coronary intervention （PCI） of chronic total occlusion （CTO）. Methods： We enrolled patients who were confirmed to have at least one native coronary artery CTO by DSCT before they underwent selective PCI in the period from December 2007 to October 2008. A CTO was defined as an obstruction of a native coronary artery with no luminal continuity. The CT-guided PCI procedure involved placing CT and fluoroscopic images side-by-side on the screen. DSCT images were analyzed for location, segment, plaque characteristics, calcification, and proximal lumen diameter of the CTO before PCI. The guidewire was advanced and manipulated under CT guidance. The PCI was carried out and the results were compared. Results： Seventy-four CTOs were assessed. PCI was successful in 57 cases of CTOs （77.0%）. According to the results, CTOs were divided into two groups： successfuI-PCI and failed-PCI. All coronary artery paths of CTOs were clearly recognized by DSCT. In the successfuI-PCI group, soft plaques were detected much more often than those in the failed-PCI group, but fibrous and calcified plaques were seen more often in the failed-PCI group. Calcification severity in CTO segments showed a significant difference between the groups （P=0.014）. Calcified plaques were detected in 20 （35.1%） lesions in the successfuI-PCI group. More than 70% of the failures were calcified plaques, of which there were two arc-calcified and one circular-calcified lesions. Occlusions were longer in the failed-PCI group than those in the successfuI-PCI group [（38.8±25.0） vs. （18.0±15.3） mm, respec- tively, P〈0.01]. Fewer guidewires were used in the successfuI-PCI group compared with the failed-PCI group （1.7±1.0 vs. 2.5±0.9, respectively, P〈0.01）. The logistic regression analysis indicated that predictors of recanalization of CTOs included occlusion length （P=-0.0035, risk ratio （RR）=0.93） and calcification severity （P=0.05, RR=0.27）. Multi-linear trends analysis showed that the factors affecting procedural time were CTO location （P=-0.0141） and occlusion length （P=0.0035）. Conclusions： DSCT could delineate the path of CTOs and characterize plaques. The outcomes of PCI were related to thrombolysis in myocardial infarction （TIMI） flow grade, CTO characteristics, severity of calcified plaques and the length of occlusive segments. Occlusion length and calcification severity were independent predictors of CTOs. Occlusion length and CTO segments could also help to estimate the duration of interventional procedures.

双源CT造影对冠心病诊断及经皮冠状动脉介入治疗支架内再狭窄评估的价值分析

目的:探究双源CT造影(DSCTA)在冠心病诊断及经皮冠状动脉介入治疗(PCI)术后支架内再狭窄的预测评估价值。方法:选取在医院欲行PCI术治疗的88例冠心病患者,所有患者术前及PCI术后6个月均采用DSCTA及冠状动脉造影(CAG)检查,以CAG检查结果为“金标准”,对患者左冠状动脉主干、左前降支、左回旋支、右冠状动脉等298段冠状动脉血管的狭窄情况进行评估,并对比DSCTA检查对冠心病诊断及PCI支架内再狭窄预测的灵敏度、特异度、阳性预测值、阴性预测值及准确率。结果:在88例患者中的298段冠状动脉血管中,CAG诊断评估血管狭窄程度中无明显狭窄、中度狭窄和重度狭窄分别为234段、47段和17段,DSCTA诊断分别为231段、46段和21段,两种诊断方法的血管狭窄评估比较差异无统计学意义(χ^(2)=0.088,χ^(2)=0.013,χ^(2)=0.450;P>0.05)。在88例患者植入的134枚支架中,DSCTA诊断与CAG诊断评价结果比较,差异无统计学意义(χ^(2)=0.579,P>0.05)。DSCTA检查诊断冠状动脉狭窄的诊断准确率、灵敏度、特异度、阳性预测值和阴性预测值分别为94.97%、90.63%、96.15%、86.57%和97.40%;诊断PCI支架内再狭窄的诊断准确率、灵敏度、特异度、阳性预测值和阴性预测值分别为92.54%、95.65%、90.91%、84.62%和97.56%。结论:DSCTA在冠心病诊断与PCI中支架再狭窄评价具有良好的一致性,且安全、价格低廉,并可为临床诊断提供更全面的冠状动脉诊断信息。

双源CTA与DSA评价冠状动脉钙化性斑块管腔狭窄对比研究

目的:探讨双源CT冠状动脉成像(DSCTA)评价钙化斑块引起血管腔狭窄的准确性。方法:62例患者DSCTA显示冠状动脉一处或多处钙化斑块,并行冠状动脉造影(CAG)检查。钙化斑块大小分为小、中和大。使用各种后处理技术,以确定钙化斑块引起血管阻塞(狭窄管腔直径≥50%),无血管阻塞(狭窄管腔直径<50%),并与CAG比较。结果:DSCTA显示小钙化斑块122处,中44处,大86处。122处小钙化斑块,5%CAG显示有梗阻;44处中钙化斑块,14%梗阻;86大钙化斑块,42%有梗阻。DSCTA与CAG一致95%(116/122)小钙化斑块、91%(40/44)中钙化斑块、67%(58/86)大钙化斑块。DSCTA低估2例小钙化斑块血管腔狭窄,高估4例小钙化斑块、4例中钙化斑块、28例大钙化斑块血管腔狭窄。86处大钙化斑块引起的血管腔梗阻,DSCTA敏感性100%、特异性44%、阳性预测值56%、阴性预测值100%、准确性67%。结论 DSCTA准确显示90%以上小和中等大小钙化斑块血管阻塞病变,正确诊断约2/3大钙化斑块血管阻塞病变。判断错误通常是高估狭窄程度。

Significance of an Advanced Image-Based Virtual Monoenergetic Reconstruction of Dual Source Dual-Energy CT Data at Low keV Increases Image Quality for Portal Vein System of Pancreatic Cancer Patients

Purpose: To explore the significance of dual-source computed tomography (DECT) virtual monoenergetic reconstructions technology in improving image quality for portal vein system of pancreatic cancer patients. Materials and methods: 47 patients with clinically suspected pancreatic cancer (all confirmed by pathology) were collected. Routine plain scan was performed with Siemens Force dual-source dual-energy CT followed by 3 scans respectively carried out in arterial phase, portal phase and delayed phase. Traditional virtual monoenergetic reconstructions (Mono_E) and new generation of virtual monoenergetic reconstructions (Mono+) were respectively performed on portal vein images to obtain virtual single energy images including Mono_ E70 keV, Mono_E 55 keV and Mono+ 70 keV and Mono+ 55 keV. The signal-to-noise ratio (SNR) and noise of portal vein, normal pancreatic tissues and pancreatic lesions of 100 kV, Mono_E and Mono+ images were compared. In addition, the contrast noise ratio of portal vein and lesions as well as pancreatic tissues and lesions (CNR PV, CNRtumor) were also compared. At the same time, two imaging physicians with rich clinical experiences read the films and scored the images of each group by using the 5-point scoring method. Results: Mono+ 55 keV images including SNRpv, SNRpanc, SNRtumor, Noise, CNRpv, CNRtumor were statistically different from 100 KV images and Mono_E images (P < 0.05). As for the subjective score, Mono+ 55 keV image score also had the highest score, which had statistical significance (P < 0.05). The results showed that Mono+ 55 keV images had the best quality. Conclusion: The new generation of virtual Mono+ post-treatment can reduce image noise. Low energy Mono+ images can improve the contrast between pancreatic cancer lesions and portal of pancreatic cancer patients.