ECG-gated Coronary Computed Tomography Angiography Research Articles

Myocardial fat accumulation is associated with cardiac dysfunction in patients with type 2 diabetes, especially in elderly or female patients: a retrospective observational study

BackgroundEctopic fat is fat that accumulates in or around specific organs or compartments of the body including myocardium. The clinical features of type 2 diabetes patients with high fat accumulation in the myocardium remain unknown. Moreover, little is known about the influence of myocardial fat accumulation in type 2 diabetes on coronary artery disease and cardiac dysfunction. We aimed to clarify the clinical features, including cardiac functions, of type 2 diabetes patients with myocardial fat accumulation.MethodsWe retrospectively enrolled type 2 diabetes patients who underwent ECG-gated coronary computed tomography angiography (CCTA) and abdominal computed tomography (CT) scan examinations within 1 year of CCTA from January 2000 to March 2021. High fat accumulation in the myocardium was defined as the low mean myocardial CT value of three regions of interest, and the associations between CT values and clinical characteristics or cardiac functions were assessed.ResultsIn total, 124 patients were enrolled (72 males and 52 females). The mean age was 66.6 years, the mean BMI was 26.2 kg/m2, the mean ejection fraction (EF) was 67.6%, and the mean myocardial CT value was 47.7 Hounsfield unit. A significant positive correlation was found between myocardial CT value and EF (r = 0.3644, p = 0.0004). The multiple regression analyses also showed that myocardial CT value was independently associated with EF (estimate, 0.304; 95% confidence interval (CI) 0.092 to 0.517; p = 0.0056). Myocardial CT value showed significant negative correlations with BMI, visceral fat area and subcutaneous fat area (r = − 0.1923, − 0.2654, and -0.3569, respectively, p < 0.05). In patients who were ≥ 65 years or female, myocardial CT value showed significant positive correlations with not only EF (r = 0.3542 and 0.4085, respectively, p < 0.01) but also early lateral annular tissue Doppler velocity (Lat e’) (r = 0.5148 and 0.5361, respectively, p < 0.05). The multiple regression analyses showed that myocardial CT value was independently associated with EF and Lat e’ in these subgroups (p < 0.05).ConclusionsPatients with type 2 diabetes, especially in elderly or female patients, who had more myocardial fat had more severe left ventricular systolic and diastolic dysfunctions. Reducing myocardial fat accumulation may be a therapeutic target for type 2 diabetes patients.

Successful treatment of acute myocardial injury of Duchenne muscular dystrophy with steroids: a case report

BackgroundDuchenne muscular dystrophy (DMD) is an X-linked muscular disease which is caused by the absence of dystrophin. Troponin elevation with acute chest pain may indicate acute myocardial injury in these patients. We report a case of DMD that presented with ACP and troponin elevation, who was diagnosed with acute myocardial injury, and successfully treated with corticosteroids.Case presentationA 9-year-old with DMD was admitted to the emergency department with the complaint of acute chest pain. His electrocardiogram (ECG) revealed inferior ST elevation and serum troponin T was elevated. The transthoracic echocardiography (TTE) demonstrated inferolateral and anterolateral hypokinesia with depressed left ventricular function. An ECG-gated coronary computed tomography angiography ruled out acute coronary syndrome. Cardiac magnetic resonance imaging revealed mid-wall to sub-epicardial late gadolinium enhancement at the basal to the mid inferior lateral wall of the left ventricle and corresponding hyperintensity on T2-weighted imaging, consistent with acute myocarditis. A diagnosis of acute myocardial injury associated with DMD was made. He was treated with anticongestive therapy and 2 mg/kg/day of oral methylprednisolone. Chest pain resolved the next day, and ST-segment elevation returned to normal on the third day. Troponin T decreased in the sixth hour of oral methylprednisolone treatment. TTE on the fifth day revealed improved left ventricular function.ConclusionDespite advances in contemporary cardiopulmonary therapies, cardiomyopathy remains the leading cause of death in patients with DMD. Acute chest pain attacks with elevated troponin in patients with DMD without coronary artery disease may indicate acute myocardial injury. Recognition and appropriate treatment of acute myocardial injury episodes in DMD patients may delay the development of cardiomyopathy.

Deep learning-based noise reduction for coronary CT angiography: using four-dimensional noise-reduction images as the ground truth.

To assess low-contrast areas such as plaque and coronary artery stenosis, coronary computed tomography angiography (CCTA) needs to provide images with lower noise without increasing radiation doses. To develop a deep learning-based noise-reduction method for CCTA using four-dimensional noise reduction (4DNR) as the ground truth for supervised learning. \We retrospectively collected 100 retrospective ECG-gated CCTAs. We created 4DNR images using non-rigid registration and weighted averaging three timeline CCTA volumetric data with intervals of 50 ms in the mid-diastolic phase. Our method set the original reconstructed image as the input and the 4DNR as the target image and obtained the noise-reduced image via residual learning. We evaluated the objective image quality of the original and deep learning-based noise-reduction (DLNR) images based on the image noise of the aorta and the contrast-to-noise ratio (CNR) of the coronary arteries. Further, a board-certified radiologist evaluated the blurring of several heart structures using a 5-point Likert scale subjectively and assigned a coronary artery disease reporting and data system (CAD-RADS) category independently. DLNR CCTAs showed 64.5% lower image noise (P < 0.001) and achieved a 2.9 times higher CNR of coronary arteries than that in original images, without significant blurring in subjective comparison (P > 0.1). The intra-observer agreement of CAD-RADS in the DLNR image was excellent (0.87, 95% confidence interval = 0.77-0.99) with original CCTAs. Our DLNR method supervised by 4DNR significantly reduced the image noise of CCTAs without affecting the assessment of coronary stenosis.

Association between coronary artery calcium score and in-stent restenosis after drug-eluting stent implantation.

Coronary artery calcium (CAC) is a modifiable contributor of in-stent restenosis (ISR), but quantitative analyses using a noninvasive approach are limited. We aimed to investigate the associations between CAC score derived from ECG-gated coronary computed tomography angiography (CCTA) or non-gated non-contrast chest computed tomography (NCCT) and ISR. We included 368 lesions in 194 patients with coronary drug-eluting stent implantations in final analyses. CAC was quantified using the Agatston score. Primary endpoint was ISR, defined as lumen diameter stenosis over 50% at the stent segment or its proximal or distal edges (5-mm segments adjacent to the stent), at angiographic follow-up. The CAC scores in either CCTA/2.5 mm group (r = 0.7702; P < 0.0001) or NCCT/5 mm group (r = 0.7105; P < 0.0001) were both correlated with in-stent diameter stenosis. The receiver-operating characteristic curve analysis identified a CAC score >245 in CCTA/2.5 mm group as the optimal ISR cutoff (sensitivity, 60.0%; specificity, 83.7%; area under the curve, 0.744; P < 0.001), and >209 in NCCT/5 mm group (sensitivity, 46.7%; specificity, 91.9%; area under the curve, 0.704; P < 0.001). Multivariable logistic regression models indicated a CAC score >245 in CCTA/2.5 mm group and >209 in NCCT/5 mm group independently associated with an 8.46- and 21.89-fold increase in ISR, respectively (all P < 0.01). Either a CAC score >245 in CCTA/2.5 mm or >209 in NCCT/5 mm was significantly associated with increased risk in ISR.

Diagnostic accuracy of early computed tomographic coronary angiography to detect coronary artery disease after out-of-hospital circulatory arrest

AimTo test the diagnostic accuracy of ECG-gated coronary computed tomography angiography (CCTA) to detect coronary artery disease (CAD) among survivors of out-of-hospital circulatory arrest (OHCA). MethodsWe prospectively studied head-to-pelvis computed tomography (CT) scanning (<6 h from hospital arrival) in OHCA survivors. This sub-study tested the primary outcome of CCTA diagnostic accuracy to identify obstructive CAD (≥50% stenosis) compared to clinically-ordered invasive coronary angiography. Patients were not optimized with beta receptor blockade or nitroglycerin. Secondary analyses included CCTA accuracy for CAD in major coronary arteries, obstructive disease at ≥70% stenosis threshold, and where non-evaluable CCTA segments were considered either obstructive or non-obstructive. ResultsOf the 104 enrolled OHCA survivors, 28 (27%) received both CT and invasive angiography in this sub study. All CCTA studies were evaluable although 49/346 (14%) individual coronary segments were unevaluable, primarily due to being too small to evaluate (65%). Patient-level diagnostic accuracy for the ≥50% stenosis threshold was high at 0.93 (95% CI 0.77–0.98) with a specificity of 1.0 (95% CI 0.8–1.0), sensitivity of 0.85 (95%CI 0.58–0.96), negative predictive value of 0.88 (95% CI 0.66–0.97) and positive predictive value of 1.0 (0.74–1.0). When non-evaluable segments were considered obstructive, the sensitivity rose to 0.92 (95% CI 0.67–0.99) with lower specificity of 0.27 (95% CI 0.11–0.52). ConclusionEarly CCTA of OHCA survivors has high diagnostic accuracy to detect obstructive coronary artery disease. However, the number of non-diagnostic coronary segments is high suggesting further CCTA refinement is needed, such as the pre-CCTA use of nitroglycerin. Clinical Trial RegistrationNCT03111043 https://clinicaltrials.gov/ct2/show/record/NCT03111043

Evaluation of LVDD by CCTA with Dual-source CT in Type 2 Diabetes Mellitus Patients.

Left ventricular diastolic dysfunction (LVDD) is a common abnormality among patients in T2DM. We aimed to evaluate the feasibility of coronary computed tomography angiography (CCTA) for the assessment of LVDD in type 2 diabetes mellitus (T2DM) patients. 80 consecutive T2DM patients who were referred for a clinically dual-source CCTA examination to evaluate suspected coronary artery disease and also underwent 2D echocardiography within 7 days of CCTA inclusion and exclusion criteria, were performed. Correlation between CCTA and echocardiography was tested through linear regression and Bland-Altman analysis. In total, 60 T2DM patients were included for the analysis. Pearson correlation showed good correlation for E (r = 0.28; P = 0.028), E/A (r = 0.69; P < 0.01); E (r = -0.06; P = 0.776), E/A (r = 0.54; P = 0.003) and E (r = 0.64; P < 0.01), E/A (r = 0.83; P < 0.01) in three groups, respectively. Overall, diagnostic accuracy for assessment in CCTA of diastolic dysfunction was 79.76% (95% CI: 68%-91%), 71.43% (95% CI: 58%-85%) and 87.50 (95% CI: 79%-96%) in three groups. The presented study proved that CCTA showed good correlations in the estimation of LV filling pressures compared with echocardiography in T2DM patients. Accordingly, retrospectively ECG-gated CCTA may provide valuable information on the evaluation of LVDD in T2DM patients.

Pulmonary Hypertension Parameters Assessment by Electrocardiographically Gated Computed Tomography: Normal Limits by Age, Sex, and Body Surface Area in a Chinese Population.

Pulmonary hypertension (PH) parameters such as pulmonary artery or right ventricular size can be measured easily on computed tomography (CT). However, there are limited data on electrocardiographically (ECG) gated CT. We sought to determine age-specific and sex-specific normal reference values for PH parameters normalized by body surface area (BSA) using ECG-gated cardiac CT in a Chinese population. In total, we enrolled 519 non-PH patients undergoing ECG-gated CT coronary angiography and measured PH parameters, including main pulmonary artery (MPA) and right pulmonary artery (RPA) diameters and distension, the ratio of MPA to ascending aorta (AAO) diameter (MPA/AAO), and the ratio of right ventricular to left ventricular diameter (RV/LV). Maximum MPA and RPA diameters were also normalized to BSA (nMPA, nRPA). Age, sex, BSA, and body mass index (BMI) were variably associated with PH parameters. Age was an independent predictor of all PH parameters. The maximum MPA diameter (26.5±2.7 mm), maximum RPA diameter (20.9±3.0 mm), nMPA (15.8±2.0 mm/m), nRPA (12.4±2.0 mm/m), and RV/LV (0.85±0.11) increased with age. MPA/AAO (0.80±0.10), MPA, and RPA distension (25.4%±7.1%; 23.3%±6.7%) correlated negatively with age. Although absolute MPA and RPA diameters were slightly larger in men, women had significantly larger nMPA and nRPA values. MPA and RPA sizes and RV/LV were correlated positively with BSA and BMI. Using ECG-gated cardiac CT, we determined the normal reference values of PH parameters for non-PH adult Chinese patients, and these values were variably influenced by age, sex, BSA, and BMI.

Personalized administration of contrast medium with high delivery rate in low tube voltage coronary computed tomography angiography.

High delivery rate is an important factor in optimizing contrast medium administration in coronary computed tomography angiography (CCTA). A personalized contrast volume calculation algorithm incorporating high iodine delivery rate (IDR) can reduce total iodine dose (TID) and produce optimal vessel contrast enhancement (VCE) in low tube voltage CCTA. In this study, we developed and validated an algorithm for calculating the volume of contrast medium delivered at a high rate for patients undergoing retrospectively ECG-gated CCTA with low tube voltage protocol. The algorithm for an IDR of 2.22 gI·s-1 was developed based on the relationship between VCE and contrast volume in 141 patients; test bolus parameters and characteristics in 75 patients; and, tube voltage in a phantom study. The algorithm was retrospectively tested in 45 patients who underwent retrospectively ECG-gated CCTA with a 100 kVp protocol. Image quality, TID and radiation dose exposure were compared with those produced using the 120 kVp and routine contrast protocols. Age, sex, body surface area (BSA) and peak contrast enhancement (PCE) were significant predictors for VCE (P<0.05). A strong linear correlation was observed between VCE and contrast volume (r=0.97, P<0.05). The 100-to-120 kVp contrast enhancement conversion factor (Ec) was calculated at 0.81. Optimal VCE (250 to 450 HU) and diagnostic image quality were obtained with significant reductions in TID (32.1%) and radiation dose (38.5%) when using 100 kVp and personalized contrast volume calculation algorithm compared with 120 kVp and routine contrast protocols (P<0.05). The proposed algorithm could significantly reduce TID and radiation exposure while maintaining optimal VCE and image quality in CCTA with 100 kVp protocol.

Evaluation of coronary artery variations using dual-source coronary computed tomography angiography in neonates with transposition of the great arteries.

The purpose of this study was to investigate whether the origins and courses of the coronary arteries could be better assessed using ECG-gated dual-source computed tomography (CT) than with echocardiography in neonates with transposition of the great arteries (TGA). A total of 17 neonates within 14days old who underwent both echocardiography and retrospective ECG-gated coronary CT angiography were retrospectively reviewed. The patients were sedated and intubated during CT examinations, and CT images were obtained with a breath-hold. CT images were reconstructed by multiple cardiac phases, and the coronary artery assessment was performed in the most static phase. Coronary anomalies were classified by Shaher's classification and validated by surgical findings. CT correctly classified 16 of 17 cases (Shaher type 1: 7, type 2: 4, type 9: 3, type 3: 1, type 4: 2), whereas echocardiography classified only 8 of 17 cases correctly. Dual-source CT had a significantly higher diagnostic ability than echocardiography (p = 0.0078). Dual-source coronary CT angiography has a higher diagnostic ability than echocardiography in the assessment of the origins and courses of the coronary arteries in neonates with TGA.

Geometrical characteristics of aortic root and left ventricular dysfunction in aortic stenosis: quantification of 256-slice coronary CT angiography.

The purpose of this study is to analyze the geometrical characteristics of aortic root and left ventricular (LV) function in aortic stenosis (AS) using 256-slice coronary-computed tomography angiography (CCTA). Retrospective ECG-gated 256-slice CCTA data from 32 patients with tricuspid AS scheduled for aortic valve replacement, and 11 controls were analyzed. Aortic root geometry was measured using multiplanar reconstruction CT images. CCTA data set was transformed into 100 phases/cycle using motion coherence image processing. Systolic shortening (SS, mm/ms) and diastolic relaxation (DR, mm/ms2) in the circumferential and longitudinal directions on time curves of myocardial length were calculated, and were used as estimates of geometric LV function. Comparison of parameters was analyzed by Mann-Whitney U test. Receiver-operating-characteristic (ROC) analysis was performed to determine the optimal cutoff of parameters for differentiating AS patients. Height of the right coronary cusp was significantly lower for AS patients than controls (11.4±2.4 vs. 13.9±2.0mm/m2, p<0.005). Vertical-longitudinal SS was significantly lower for AS patients than for controls (1.7±0.8 vs. 2.7±0.7mm/ms/m2, p<0.001). ROC analysis revealed optimal height of the right coronary cusp of 12.4mm/m2 and vertical-longitudinal SS of 2.4mm/ms/m2 for differentiating AS patients from controls, with C statistics of 0.82 and 0.85. In AS patients, ROC analysis revealed optimal vertical-longitudinal DR of 0.05mm/ms2/m2 for predicting patients with stroke volume index <35ml with C statistics of 0.93. Quantification of CCTA demonstrates that AS is characterized by small coronary cusps as aortic root remodeling and vertical-longitudinal LV dysfunction related to restrictive physiology.

Surgical decision-making in aortic prosthetic valve endocarditis: the influence of electrocardiogram-gated computed tomography.

The aim of this study was to investigate the value of electrocardiogram (ECG)-gated computed tomography (CT) in the surgical decision-making and preoperative evaluation in patients with aortic prosthetic valve endocarditis (PVE). Sixty-eight prosthetic valves in 67 patients with aortic PVE were prospectively evaluated with ECG-gated CT and transoesophageal echocardiography (TEE). Imaging findings considered indications for surgery were as follows: (i) abscess/pseudoaneurysm formation; (ii) prosthetic valve dehiscence; (iii) valve destruction with valvular regurgitation; (iv) large vegetations (>1.5 cm). The coronary arteries were evaluated with ECG-gated CT. Clinical data including surgical reports and mortality data were collected. Fifty-eight of 68 cases had indication for surgery based on imaging findings (ECG-gated CT/TEE). In 8 of these cases (14%), there was indication for surgery based on CT but not on TEE findings (all had perivalvular pseudoaneurysms). In 11 cases (19%), there was indication for surgery based on TEE but not on CT findings [non-drained abscess (n = 5), prosthetic valve dehiscence (n = 4), large vegetation (n = 1), valve destruction (n = 1)]. In 31 of 32 patients with indication for preoperative coronary angiography, ECG-gated CT coronary angiography was diagnostic. In 1 patient, ECG-gated CT coronary angiography was inconclusive and invasive coronary angiography was performed. In patients with aortic PVE, ECG-gated CT provides additional information over TEE regarding perivalvular extension of infection, which can influence surgical decision-making. Furthermore, ECG-gated CT provides a non-invasive coronary angiogram and can in most cases replace invasive coronary angiography in the preoperative evaluation.

Assessment of aortic valve in regard to its anatomical variants morphology in 2053 patients using 64-slice CT retrospective coronary angiography.

BackgroundBicuspid aortic valve (BAV) is the most common congenital cardiac anomaly. Other aortic valve variants are rare but are associated with an increased incidence of various pathologies of the aortic valve (AV). The aim of this study was to assess the AV function in regard to its anatomical variants morphology in patients who underwent 64-slice coronary computed tomography angiography (CCTA) for suspected or known coronary artery disease.MethodsThe results of 64-detector retrospective ECG-gated CCTA of 2053 patients (mean age 58 years; 1265 males) were analyzed retrospectively by experienced cardiovascular radiologist. Coronary anatomy (with coronary artery dominance) and the extent of occlusion in the coronary arteries were assessed. Furthermore morphological and functional status of AV variants were analyzed. Among measured parameters were area at the level of AV annulus, orifice and tubular portion of the ascending aorta.ResultsThe AV was visualized in all CCTA studies and the analysis of its morphology and function was done in all patients. BAV was found in 19 patients (0.9 %), from which type 0 was diagnosed in five patients (0.2 %) and type 1 in 14 patients (0.7 %) - there was no patient with BAV type 2. Unicuspid (UAV) and quadricuspid (QAV) variant were both observed each in one patient (0.05 %). In rest of the patients from the study group tricuspid AV variant was recognized. Function of AV variants was mostly affected in BAV0 and UAV. Among patients with BAV1 there were patients with normal and abnormal function of AV. QAV variant did not deteriorate AV function. There was no difference in coronary artery disease and dominancy between different anatomical variants of AV.ConclusionsDuring CCTA different valve variants can be detected and detailed analysis of valvular function can be proceeded. Larger values of annulus area, wider diameters of ascending aorta and more stenotic profile were observed in BAV 0, BAV 1 and UAV. Among AV variants morphology and function was mostly affected in patients with BAV 0 and UAV variants, while subjects with BAV1 had normal or abnormal function of the AV. Moreover, we noticed that QAV variant did not deteriorate AV function.Electronic supplementary materialThe online version of this article (doi:10.1186/s12872-016-0261-z) contains supplementary material, which is available to authorized users.

Organ and effective dose evaluation in coronary angiography by using a 320 MDCT based on in-phantom dose measurements with TLDs

The purpose of this study is to estimate the organ and effective dose (E) from computed tomography coronary angiography (CTCA) on a 320-MDCT scanner. Radiation dose was estimated for the prospectively ECG-gated CTCA in a male phantom. A total of 451 chips of thermoluminescent dosimeter were implanted in the phantom for measuring the organ doses. The effective doses were calculated using measured organ doses and the tissue-weighting factors. The dose length product (DLP) values were recorded and used to develop the conversion coefficient k = 0.017 mSv•(mGy•cm)−1 (E/DLP). In a 3-beat acquisition, the organ doses ranged from 0.24 to 71.55 mGy, and the doses in breast, bone surface, oesophagus, and lung were higher than 20 mGy. The effective doses in 2-beat and 3-beat acquisition were estimated to be 14.3 and 24.3 mSv. More beats of acquisition led to higher radiation dose. The reported k values for chest CT scan can be used to roughly estimate the E value from CTCA for 320 MDCT.

Diagnostic accuracy of prospective ECG gated coronary computed tomography on a 256 slices scanner: Daily practice experience

To determine the accuracy of prospective ECG-gated computed tomography coronary angiography (CTCA) using 256-slice scanner for detecting significant coronary artery disease (CAD) and to quantitatively estimate lumen narrowing with CTCA in comparison to invasive coronary angiography (ICA). This study included 109 consecutive patients who had ICA on the basis of a previous CTCA (within 60 days) for clinical suspicious of CAD. All CTCA scans were performed with a 256-slice scanner using prospective ECG-gated image acquisition. The presence of stenosis ⩾ 50%, measured by QCA for ICA and Visual assessment for CTCA, was considered significant stenosis. Obstructive CAD was present in 73.4% of patients. On patient-based analysis, the sensitivity of CTCA was 98%, specificity 83%, PPV 94% and NPV 92%. For segment-based analysis, a total of 1584 segments were analyzed with a sensitivity of 89%, specificity 98%, PPV 85% and NPV 99%. High correlation was observed between degrees of luminal stenosis assessed by CTCA in comparison to QCA in all segments (r 2 = 0.961). There was high agreement between observers regarding the presence of significant luminal stenosis ( k = 0.78) and good correlation for percentage of luminal stenosis ( r = 0.68, p < 0.001) between both readers. In a highly prevalence diseased population, prospective ECG-gated CTCA using 256-slice scanner is highly accurate for detection and quantification of the degree of coronary luminal stenosis in comparison to ICA.

Prevalence of congenital coronary artery anomalies and variants in 726 consecutive patients based on 64-slice coronary computed tomography angiography

Coronary computed tomography angiography (CCTA) is helpful in making a precise noninvasive evaluation of coronary anatomy, allowing concomitant evaluation of other cardiac structures. The aim of this study was to determine the prevalence of coronary artery variations detected by 64-slice multi detector CT. The results of ECG-gated CCTA in 726 consecutive patients (mean age 58 years) were analysed retrospectively. The main indications for CCTA were a typical chest pain, angina pectoris, screening for coronary artery disease and determination of the patency of bypass grafts or stents. Acquisition was performed with a 64-detector CT scanner with retrospective ECG gating. Imaging results were assessed by experienced cardiovascular radiologist. The overall incidence of coronary artery anomalies was 1.1% (8 out of 726 participants). The most common anomaly was an anomalous origin of the circumflex artery from the right coronary sinus with a retroaortic course (4 patients,0.6%), followed by origin of right coronary artery from the left coronary sinus (2 patients, 0.3%). One patient with abnormal origin of the left main artery from the right coronary sinus (0.1%) and 1 patient with a circumflex artery origin from the proximal segment of the right coronary artery (0.1%) were observed, both with retroartic course. CCTA is a noninvasive imaging technique useful for the precise evaluation of variations of the coronary arteries. This study shows similar results to other reports on this subject.

Coronary Computed Tomography Angiography‐Based Tricuspid Annular Plane Systolic Excursion: Correlation with 2D Echocardiography

Right heart evaluation on coronary computed tomography angiography (CCTA) is underutilized due to nonopacification of the right heart chambers and poor endocardial resolution. We analyzed feasibility and reproducibility of right heart functional analysis by measuring CCTA-based tricuspid annular plane systolic excursion (CT-TAPSE) on ECG-gated CCTA and correlated the results with 2D transthoracic echocardiography (TTE)-derived TAPSE (Echo-TAPSE). CT-TAPSE was measured on a total population of 41 patients who had CCTA and TTE performed within 6 months of each other. Two independent CCTA readers performed analysis on reformatted four-chamber view. Intra- and inter-observer variability analysis was performed on 16 randomly selected patients. Correlative (Spearman's R) and Bland-Altman analysis was used to assess the level of agreement between the 2 methods and to compare CT-TAPSE with Echo-TAPSE. CT-TAPSE measured by Readers 1 and 2 on 16 randomly selected patients, demonstrated excellent intra-observer and inter-observer agreement, with very close correlation (R > 0.80 and 2-tailed P-value of <0.001). When tested in the entire study population of 41 patients, CT-TAPSE correlated closely with Echo-TAPSE (R = 0.738, P < 0.001). Bland-Altman analysis indicated that the 2 methods provided similar measures as majority of values lay within the 95% confidence limits. Based on abnormal Echo-TAPSE cutoff value of <16 mm, CT-TAPSE identified impaired right ventricle (RV) function with sensitivity of 82% and specificity of 93%, respectively. We demonstrated feasibility and reproducibility of assessing TAPSE on coronary CTA. RV functional analysis utilizing CT-TAPSE is simple and reproducible methodology, and is in close agreement with Echo-TAPSE.

The role of intravascular ultrasound scan and thin-sliced coronary computed tomography angiography in diagnosing aortic dissection causing acute myocardial infarction

Introduction: Acute aortic dissection is a disease of high mortality. The symptoms may mimic other conditions and misdiagnosed, such as acute coronary syndrome, coronary involvement complicates the clinical scenario and increases mortality. Case Report: We herein report a case of an acute myocardial infarction caused by acute aortic dissection. Without noticing the aortic dissection, we performed emergent coronary angiography, which showed severe stenosis of the proximal right coronary artery. Intravascular ultrasound scan led us to suspect aortic dissection. However, we performed balloon angioplasty because the patient's hemodynamic status was unstable. ECG-gated coronary computed tomography angiography provided a definitive diagnosis, and the patient underwent successful surgical repair of the aortic dissection. Conclusion: Acute coronary syndrome associated with acute aortic dissection is not rare. However, the management of these conditions depends on the details of each case. This case demonstrates the difficulty of treating such cases in the real world. Herein, we describe educational imaging findings and briefly discuss the management of cases involving acute coronary syndrome associated with acute aortic dissection.

Reduction in Observation Unit Length of Stay With Coronary Computed Tomography Angiography Depends on Time of Emergency Department Presentation

Prior studies demonstrating shorter length of stay (LOS) from coronary computed tomography angiography (CCTA) relative to stress testing in emergency department (ED) patients have not considered time of patient presentation. The objectives of this study were to determine whether low-risk chest pain patients receiving stress testing or CCTA have differences in ED plus observation unit (OU) LOS and if there are disparities in testing modality use, based on the time of patient presentation to the ED. The authors examined a cohort of low-risk chest pain patients evaluated in an ED-based OU using prospective and retrospective OU registry data. During the study period, stress testing and CCTA were both available from 08:00 to 17:00 hours. CCTA was not available on weekends, and therefore only subjects presenting on weekdays were included. Cox regression analysis was used to model the effect of testing modality (stress testing vs. CCTA) on OU LOS. Separate models were fit based on time of patient presentation to the ED using 4-hour blocks beginning at midnight. The primary independent variable was testing modality: stress testing or CCTA. Age, sex, and race were included as covariates. Logistic regression was used to model testing modality choice by time period adjusted for age, sex, and race. Over the study period, 841 subjects presented Monday through Friday. Median LOS was 18.0 hours (interquartile range [IQR] = 11.7 to 22.9 hours). Objective cardiac testing was completed in 788 of 841 (94%) patients, with 496 (63%) receiving stress testing and 292 (37%) receiving CCTA. After age, race, and sex were adjusted for, patients presenting between 08:00 and 11:59 hours not only had a shorter LOS associated with CCTA (p < 0.0001), but also had a greater likelihood of being tested by CCTA (p = 0.001). None of the other time periods had significant differences in LOS or testing modality choice for CCTA relative to stress testing. In an OU setting with weekday and standard business hours CCTA availability, CCTA testing was associated with shorter LOS among low-risk chest pain patients only in patients presenting to the ED between 08:00 and 11:59 hours. That time period was also associated with a greater likelihood of being tested by CCTA, suggesting that ED providers may have intuited the inability of CCTA to shorten LOS during other times.

Radiation dose study of 64-slice spiral CT coronary angiography: a paired design

To compare image noise and radiation dose differences between prospective and retrospective ECG-gated computed tomography (CT) coronary artery imaging with 64-slice spiral CT (64-MSCT) in a paired design. Prospective and retrospective ECG-gated CT coronary angiography was performed among 20 out-patients with suspected coronary artery diseases. If one protocol failed, chose the other instead. The differences in effective dose (ED), image noise, contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) between the two scan protocols were compared. Usual causes of failures were analysed for each. The average ED of retrospective and prospective protocol was 21.6±2 and 6.0±1.2 mSv, respectively. There was a significant statistical difference in the two protocols (p < 0.05 and 6.16e(-14)). The image noise and SNR between the two protocols made no differences (p=0.71, 0.26, >0.05). The average image noise and SNR of retrospective and prospective protocol were (27.95±2.82, 28.66±2.9) and (12.15±1.83, 10.9±1.17). The CNR of retrospective and prospective protocol was (14.52±1.59) and (17.3±2.09), respectively. There was a statistical difference (p < 0.05 and 0.045). The prospective protocol can lower the ED of 64-MSCT a lot than the retrospective protocol. The image noise and SNR made no differences, whereas the prospective protocol gave a better CNR result.

Low dose coronary CT angiography with 256-slice helical CT

Objective To compare the image quality and patient radiation dose of coronary computed tomography angiography (CCTA) received by prospectively-gated step-and-shoot (SAS) technique with those obtained by retrospectively-gated spiral (RGS) technique on a 256-slice CT scanner. Methods A total of 200 patients were enrolled in this study. One hundred patients underwent CCTA with SAS mode were subdivided into two groups: ( 1 ) 50 patients with an average heart rate (HR) ≤70 bpm were scanned with a data acquisition time window centered at the 75％ of the R-R cycle ( group A) and (2) 50 patients with HR ＞ 70 bpm were scanned with the data acquisition time window centered at the 45％ of the R-R cycle, including a phase tolerance of ±％ (group B). Other 100 patients underwent CCTA with RGS mode and ECG-based tube current modulation were also subdivided into two groups: (3) 50 patients with HR ≤70 bpm were scanned with cardiac dose right set to phase of 75％ (group C) and (4) 50 patients with HR ＞ 70 bpm were scanned with cardiac ose Rdight set to phases of 45％ and 75％ (group D). All patients were grouped in randomized order. The image quality of CCTA were evaluated using a rank scale from 1 to 4 ( 1 : excellent ; 4 : non-assessable ) . Radiation dose of the four groups received was also estimated. The image quality between groups was compared by Mann-Whitney U test. The radiation dose between groups was compared by t test. For the 100 patients received by prospective ECG-gated CCTA, the receiver operating characteristic curve (ROC) was used to analyze the CCTA image quality and average heart rate to determine the uppercutoff of HR for obtaining diagnostic coronary images with SAS mode. A spearman correlation analysis was also performed to analyze the correlation of HR and image quality in patients underwent CCTA with SAS mode. Results Of 2338 coronary artery segments, excellent or good image quality( score of 1 or 2) was achieved in 96. 5％ (585 of 606) in group A, 77.7％ (445 of 573 ) in B,96. 1％ (548 of 570) in C, and 85. 7％ (505/589) in D, with no significant difference for A vs C(Z ＝- 1. 351 ,P ＞0. 05) and with significant differenceS for B vs D (Z＝ -2. 236,P ＜0. 05). Linear correlation analysis indicated a significant degradation of image quality with the increase of heart rate using SAS mode (Spearman correlation, r ＝ 0. 577, P ＜0. 01 ). ROC analysis established an upper HR threshold of 78 bpm for obtaining diagnostic image quality using SAS mode( AUC ＝ 0. 827, P ＜ 0. 05 ). The average radiation dose in group A [ ( 2. 6 ± 0. 5 ) mSv]reduced 75 ％ comparing with that in group C [ ( 10. 6 ± 2. 3 ) mSy], and the average radiation dose in group B [ ( 4.0 ± 0. 7 ) mSy]reduced 69％ comparing with that in group D [ ( 13.0 ± 1. 4) mSv]. Conclusion Using SAS mode to perform low-dose CCTA with 256-slice helical CT could keep the image quality and reduce radiation dose significantly. Our preliminary experience suggests a good promise of this technique which could be applied to a wider group of patients such as with higher heart rates. Key words: Tomography, X-ray computed; Coronary vessels; Diagnostic imaging; Radiation dosage