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Objective To investigate the feasibility of coronary CT angiography in single cardiac cycle and to analyze the image quality and radiation dose in patients with high heart rate(HR) using 256-row detector CT. Methods Ninety-two consecutive patients between October and November 2015 who were suspected coronary artery disease underwent coronary CT angiography(CCTA) were enrolled, which was performed with a 256-row detector CT(Revolution CT, GE Healthcare) using prospective ECG-triggered volume CCTA within a single cardiac cycle with snapshot freeze(SSF) technique. The patients were grouped by HR during CT scans: group A(80—89 bpm, n=56), group B(90—99 bpm, n=20), and group C(≥100 bpm, n=16). Image quality was compared before and after using SSF technique reconstructions in seventy-four patients. The image quality of coronary artery was evaluated blindly by 2 experienced radiologists using a four-point scale based on the 18-segment model according to the Society of Cardiovascular Computed Tomography guidelines. The differences in age, body mass index, heart rate and CT dose index volume,effective dose(ED) among the three groups were compared by using ANOVA analysis or Kruskal-Wallis test, the image quality and interpretability using χ2 test. Comparisons of image quality between standard and SSF were performed with paired Wilcoxon rank sum test. Kappa coefficient was used to test inter-observer agreement. Results A total of 1 065 coronary artery segments, 98.97%(1 054/1 065) met the requirements for diagnosis. No significant difference was found(χ2=1.274, P=0.563) for the diagnostic image quality of coronary artery segments among the 3 groups with 98.64%(651/660), 99.57%(232/233), 99.42%(171/172), respectively. Significant difference(χ2=68.811, P0.05). Conclusions Single cardiac cycle scan is feasibility for coronary CT angiography in patients with high heart rate using 256-row detector CT. This scan mode can maintain the diagnostic image quality with low radiation dose. SSF technique can improve the image quality.
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Objective To evaluate the combination of dual-energy CT angiography (DE-CTA) and dual-energy CT peffusion (DE-CTP) in the diagnosis of coronary artery disease. Methods Thirty-one patients with angina pectoris were examined using dual-source dual energy CT and conventional coronary angiography. For DE-CTA, we used a contrast-enhanced ECG-gated coronary scan protocol with energy levels of two tube detector arrays at 140 and 100 kVp. Two kinds of acquired images were fused for the CT angiogram and further calculated to construct a perfusion map (Siemens DE Heart PBV). The compared the following results: DE-CTA vs. CA, DE-CTP vs. CA to assess the sensitivity and specificity, and further compared DE-CTA plus DE-CTP with CA. Results DECT obtained diagnostic image quality in 28 patients.DE-CTA detected 41/112 arterial stenosis. Using CA as a reference, the sensitivity of DE-CTA was 81%(38/47), specificity was 95% (62/65), positive predictive value was 92% (38/41), negative predictive value was 87% (62/71), and accuracy was 89% (100/112). DE-CTP detected 46 perfusion defects in artery territories. Using CA as a reference, the sensitivity of DE-CTP was 76% ( 36/47), specificity was 85% (55/65), positive predictive value was 78% (36/46), negative predictive value was 83% (55/66),and accuracy was 81% (91/112). DE-CTA plus DE-CTP diagnosed 52 arteries stenosis. Using CA as a reference, combination of DE-CTA and DE-CTP gave sensitivity of 95% ( 45/47 ), specificity of 89%(58/65) , NPV of 97% (58/60), and accuracy of 92% (103/112). Conclusions DECT can provide perfusion blood volume information as well as vessel pathology in one scan. DECT can provide comprehensive diagnosis and improve diagnosis of CAD.
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Objective To explore the feasibility of evaluating cardiac structure, coronary artery,pulmonary artery and cardiac function in one single scan by 320-row CT ECG-gated double phase cardiac function scan mode. MethodsForty patients underwent the 320-detector row CT double phase cardiovascular angiography. The pulmonary phase and aortic phase were reconstructed in order to evaluate the pulmonary and coronary artery. MPR reconstructions of both pulmonary and aortic phase were used to analyze the function of the two ventricles. And the results of the cardiac function were compared with those of transthoracic echocardiography. Thirty-five cases could be analyzed and diagnosed, while the other 5 cases had to be given up because of the poor imaging quality. The mean heart rate was (71.2 ± 11.2) beat per min (bpm). No arrhythmia case included. Results ( 1 ) Pulmonary embolism were diagnosed in 11 cases,coronary artery disease (CAD) were found in 5 cases, while post-stent implantation were observed in 7 cases. Six cases of congenital heart disease were diagnosed with 3 ASD and 3 primary pulmonary hypertension. Another one was diagnosed with left atrial myxoma, and 5 cases were pulmonary embolism associated with CAD. All of above cases were verified by final clinical diagnosis. (2) The heart function parameters including LVEDd , RVEDd, LVESd, RVESd and LVEF were (36.7 ±3.3), (43.3 ± 3.4) mm,(31.6±5.1), (41.3 ±5.1) mm and (47.1 ±15.1) for CT, while those were (40.3 ±3.1), (47.3 ±4.2) mm,(37.3 ±5.6), (45.3 ±3.3) mm,and (46.0 ± 14.8) for ultrasound, respectively. The CT results were correlated with the ultrasound ( n = 35, r = 0.886-0.988, P ＜ 0.01 ). (3) The average radiation exposure was ( 5.4 ± 0.5 ) mSv. Conclusions 320-row CT ECG-gated double phase cardiac function scan mode is feasible for the "one-stop-shop" examination of the cardiovascular disease. This noninvasive method is recommended for the diagnosis, differential diagnosis, treatment and prognosis of cardiovascular disease.
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Objective To investigate the application of low-dose adaptive sequence scan of dual-source CT coronary angiography in patients with high heart rate and evaluate the image quality.Methods Seventy-two patients who underwent coronary CT angiography with heart rate> 70 bpm were divided into 2 groups.Group A was adaptive sequence scan, and Group B was retrospective ECG-gating helical scan.Examinations were performed on a dual-source CT scanner (Somatom Definition) .All images were transferred to a workstation for further processing and analysis.The image quality was evaluated using same criteria.The image quality of coronary artery segments was compared in two groups using rank sum test, and the radiation dose was compared using t test Results A total of 501 coronary artery segments were evaluated in group A and 400 segments in group B.The mean ranks in image quality of coronary artery segments in group A was 475.42, whereas 420.41 in group B.There was a statistical difference in image quality between the two groups (Z= - 3.509,P=0.000).The effective dose was on average (6.2±0.9) mSv in group A, whereas on average (14.7±1.9) mSv in group B, there was a statistical difference between the two groups(t= - 27.011, P=0.000).Conclusions Adaptive sequence scan in dual-source CT coronary angiography is feasible in patients with high heart rates.This scan mode can substantially reduce radiation dose and maintain the diagnostic image quality.
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Objective To prospectively evaluate the influence of average heart rate,heart rate variability and ECG editing on image quality of 64-slice CT coronary angiography(CTCA)in patients with atrial fibrillation(AF).Methods Fifty patients who were diagnosed with AF underwent respective ECG-gating 64-slice CTCA Image quality(good,moderate,poor)were evaluated on vessel segment level pre-and post ECG editing.Chi-square test was performed to compare the image quality in patients with various average heart rate,heart rate variability,and pre-and post ECC editing.Pearson correlation analysis was performed to test the relationship between the image quality and average heart rate and heart rate variability.Sensitivity,specificity,positive predictive value(PPV)and negative predictive value(NPV)were calculated by using the conventional angiography as the standard reference.Results The average heart rate of the fifty AF patients was(89±23)beat/min,with variability of(18.2±6.1)beat/min.Finally,24(3.4%)segments were considered to have poor image quality in 6(12.0%)patients.Image quality decreased significantly(P＜0.05)at the average heart rate of over 100 beats per minute(11 segments)or the standard deviation of heart rate of over 24 beats per minute(11 segments).There was significant correlation between the mean heart rate and the image quality for all segments,the RCA,and distal section of coronary artery(r=0.50,0.55,0.53,0.49,0.42,0.44;P＜0.05).Heart rate variability was also significant correlated with the image quality.There was significant difference on image quality pre-and post ECG editing(P=0.013).The respective overall sensitivity,specificity,NPV,PPV values were 100%(6/6),93.2%(41/44),100%(41/41),and 66.7%(6/9).Conclusion ECG editing can improve the success rate and the image quality of 64-slice CTCA effectively in patients with AF within a certain range of average heart rates and heart rate variability.
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Objective To investigate the diagnostic value of dual-energy CT pulmonary angiography (DE-CTPA) and dual-energy CT lung perfusion (DE-CTLP) in the assessment of pulmonary embolism comparing with pulmonary ventilation-perfusion scintigraphy. Methods Fifty patients suspected of PE (26 males, 24 females) underwent both DE-CTPA, DE-CTLP and pulmonary ventilation-perfusion scintigraphy. The results were compared and the correlation between the intravascular clots in DE-CTPA and the perfusion defects in DE-CTLP was analyzed. The sensitivity, specificity and accuracy of DE-CTLP for PE were assessed according to scintigraphic results which was considered as a "gold" standard. Result ( 1 ) Of 50 cases,920 segments in 46 cases were diagnostable, 4 cases were not included because of the poor image quality. lntravascular clots were found in 262 segments on DE-CTPA and perfusion defects in 266 segments were identified on DE-CTLP, while 268 segments were positive on scintigraphy. (2) The perfusion defects on DE-CTLP were correlated well with the clots on CTPA ( r = 0. 883, P < 0. 01 ). The Dual energy CT Lung perfusion imaging had a good consistence with scintigraphy (Kappa = 0. 940, P <0. 01 ). The sensitivity, specificity, positive and negative predictive value were 96. 2% (279/290), 98.0%(641/654), 95. 5% (279/292) and 98. 3% (641/652), respectively. (3)The radiation dose of DE-CTPA and CE-CTLP scan was(4. 37 ± 0. 47) mSv by using CareDose 4D technique. Conclusion DE-CTPA and CE-CTLP can provide pulmonary vascular morphology and parenchyma perfusion information which are useful and valuable for the diagnosis of PE.
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Objective To evaluate low-dose CT coronary angiography with prospective electrocardiogram (ECG)-triggering using dual-source CT scanner.Methods Sixty-eight patients who underwent coronary CT angiography using a dual-source CT scanner were divided into 2 groups: group A (38 cases) and group B (30 cases).Prospective ECG-triggering sequence scan mode was employed for group A.Inclusion criteria included: heart rate <70 bpm, sinus rhythm, and heart rate fluctuation less than 10 bpm.Data acquisition was set at 70% of the RR-interval.Retrospective ECG-gating helical scan was performed for group B.Inclusion criteria included heart rates < 70 bpm and sinus rhythm.The exclusion criteria included heart failure and serious arrhythmias.In both groups, patients with a BMI≥24 kg/m2 were examined with a tube voltage of 120 kV, whereas patients with a BMI <24 kg/m2 were examined with a tube voltage of 100 kV.All images were transferred to a workstation for further processing and analysis.The imaging quality was evaluated.The imaging quality of coronary artery segments were compared with rank sum test between the two groups, and the radiation dose were compared with t test.Results A total of 476 coronary artery segments were evaluated in group A and 372 segments were evaluated in group B.The mean score of imaging quality for coronary artery segments in group A was 3.48±0.59 and that in group B was 3.53±0.58.There was no statistical difference in imaging quality between the two groups (Z=-1.432, P=0.187).The effective dose was on average (2.51±0.54) mSv (range 1.3--3.3 mSv) in group A, whereas on average (14.55±3.54) rosy (range 7.1--20.2 mSv) in group B.There was a statistical difference between the two groups (t=18.484, P=0.000).Conclusions Low-dose prospective ECG-triggering sequence scan in dual-source CT coronary angiography is feasible in patients with low heart rate and regular cardiac rhythm.This scan mode can substantially reduce radiation doses while preserving good diagnostic image quality.
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Objective To prospectively evaluate the feasibility and reliablity of low kilovoltage contrast-enhanced multi-slice CT(MSCT)to detect the myocardial viability in chronic myocardial infarcetion.with comparison to magnetic resonance(MR)myocardial perfusion and viability imaging.Methods Thirty-two patients with clinical diagnosed chronic myocardial infarction underwent the first pass and delayenhanced myocardial imaging with 64-slice MSCT and MR Left ventricle was divided into 16 segments.MSCT and MR images of all the patients were blindly analyzed.The size and extent of hypoenhanced regions in first pass phase and hyperenhanced regions in delayed phase were define.The Kappa test was used to assess the ability of identifying the viable myocardium between the two methods.Results In 32 patients with chronic myocardial infarction,MSCT showed hypoenhanced regions in 41 segments and normal in 471 segments during the first phase,while MRI revealed hypoenhanced regions in 47 segments and normal regions in 465 segments.The Kappa value was 0.650 and the concordance rate of the two techniques was 94.5%(484/512).MSCT showed 135 hyperenhanced regions which were non-transmural in 50 segments and transmural in 85 segments.And the other 377 normal segments showed no enhancement in the delayed phase.MRI revealed 120 hyperenhanced regions which were non-transmural in 56 segments and transmural in 64 segments.And the other 392 normal segments showed no enhancement in the delayed phase.The Kappa value of the two techniques was 0.609 and the concordance rate of the two techniques was 80.7% (413/512).Conclusion The study showed that low kilovolrage CE MSCT has a good concordance with MRI and has high feasibility and reliability in evaluating the myocardial viability in chronic myocardial infarction.The radiation dose is still the important aspect of MSCT application.
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Objective To assess the role of MR myocardial perfusion imaging (MRMPI) in detecting the viabilitive of myocardium in patient with old myocardial infarction (OMI) Methods MRMPI was performed in 47 patients suffering from old myocardial infarction with 1 5 T MR scanner Male 44, female 3, age ranged from 30 to 87 years with a mean of 61 years All patients were imaged during the first pass and delayed phase 5-30 min after injection of Gd DTPA 0 1 mmol/kg at 5 ml/s using IR turbo FLASH sequence Short axis images were acquired during the first pass, and both short axis and long axis images during delayed phase The left ventricular wall on short axis slice was divided into 8 segments A correlative study was carried out in 17 patients with the results of rest and stress 99m Tc SPECT scanning Results In 47 patients of old myocardial infarction, 29(61 7%) showed hypoenhancement during the first pass imaging (the SI was 50 20?7 45 percent of normal segment)and 46(97 9%) revealed delayed hyperenhancement(the SI was 491 0?197 26 percent of normal segment). For delayed hyperenhancement, 10(21 3%) was transmural ,15(31 9%) was nontransmural, and 21(44 7%) mixed, another one was normal 37 segments in 17 patients revealed to be nonviable by rest and stress 99m Tc SPECT, and the MRMPI all showed delayed hyperenhancement 116 viable segments on rest and stress 99m Tc SPECT, and no delayed hyperenhancement in 97 segments (83 6%) on MRMPI With the rest and stress 99m Tc SPECT as a standard of reference the sensitivity and the specificity of MRMPI were 100.0% and 83 6% respectively Conclusion The myocardial viability and nonviability as well as their severity and extent may be effectively evaluated with MRMPI in patients with OMI
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Objective To evaluate the methods and the factors of affecting imaging quality of 3D CE MRA of carotid arteries.Methods 3D CE MRA in 48 patients were performed using 1.5T super conductive MR scanner,cervical and lumbar combination phased array coils. All patients were examined using intravenous injection Gd-DTPA and breath-hold 3D FLASH sequence. Results Imaging quality was satisfied in 46/48 patients (96%). MIP and MPR could clearly showed normal anatomy. The site,size and stenosis degree of the lesion were also demonstrated. Compared to surgery,DSA and/or ultrasound results , in 23 patients, the sensitivity and specificity of 3D CE MRA were 100% and 100% respeectively for the lesion of carotid arteries. Conclusion High quality images of 3D CE MRA mainly depends on determining the best acquisition delay time,optimizing injection volume and rate of contrast material,using reasonable sequence parameters and skilled level of operators.