Dual-source CT Angiography Research Articles

Defining the optimal systolic phase targets using absolute delay time for reconstructions in dual-source coronary CT angiography.

To define the optimal systolic phase for dual-source computed tomography angiography using an absolute reconstruction delay time after the R-R interval based on the coronary artery motion, we analyzed images reconstructed between 200 and 420 miliseconds (ms) after the R wave at 20 ms increments in 21 patients. Based on the American Heart Association coronary segmentation guidelines, the origin of six coronary artery landmarks (RCA, AM1, PDA, LM, OM1, and D2) were selected to calculate the coronary artery motion velocity. The velocity of the given landmark was defined as the quotient of the route and the length of the time interval. The x, y and z-coordinates of the selected landmark were recorded, and were used for the calculation of the 3D route of coronary artery motion by using a specific equation. Differences in velocities were assessed by analysis of variance for repeated measures; Bonferroni post hoc tests were used for multiple pair wise comparisons. 1488 landmarks were measured (6 locations at 12 systolic time points) in 21 patients and were analyzed. The mean values of the minimum velocities were calculated separately for each heart rate group (i.e. <65; 65-80; and >80 bpm). The mean lowest coronary artery velocities in each segment occurred in the middle period of each time interval of the acquired systolic phase i.e. 280-340 ms. No differences were found in the minimal coronary artery velocities between the three HR groups, with the exception of the AM1 branch (p = 0.00495) between <65 and >80 bpm (p = 0.03), and at HRs of 65-80 versus >80 bpm (p = 0.006). During an absolute delay of 200-420 ms after the R-wave, the ideal reconstruction interval varies significantly among coronary artery segments. Decreased velocities occur between 280 to 340 ms. Therefore a narrow range of systolic intervals, rather than a single phase, should be acquired.

Total Effective Radiation Dose Attributable to Medical Imaging in Patients With Acute Chest Pain: A Single-Center Comparison Study Between Dual-Source Coronary CT Angiography and Usual Care

Introduction: Coronary CT angiography (CCTA) can safely disposition low to intermediate risk chest pain (CP); however, there is conflicting data with respect to cumulative radiation exposure when compared with usual care over short follow-up intervals. Objectives: We report the effective radiation dose from index and downstream testing in low to intermediate risk symptomatic patients evaluated for chest pain in the ED with either CCTA or usual care to define various sources of patient radiation dose and quantify effective dose over a year and a half of follow-up. Patients and Methods: We evaluated radiation exposure from initial and downstream testing in a prospectively collected, matched cohort evaluated for CP in the emergency department (ED) with either CCTA compared with usual care over a median follow-up of 19.6 months. Effective radiation dose was calculated using published conversion factors. Results: Prospective, ECG-triggered acquisition using a 128-slice dual-source multidetector computed tomography (DSCT) scanner was performed in 92.9% of scans with a median effective dose from CCTA of 6.8 mSv (IQR 5.2, 9.1 mSv). CCTA cohort patients were more likely to undergo cardiac testing with exposure to radiation (P < 0.001); however, the median effective dose in patients exposed to radiation from cardiac testing was significantly lower in the CCTA cohort (7.1 mSv vs. 11.8 mSv, P < 0.001). Fewer patients in the CCTA cohort had additional non-cardiac thoracic imaging radiation exposure (40.8%) compared with usual care (92.8%). Total radiation exposure from any source was similar between the CCTA and usual care groups (100% vs 98.4%, P = 0.087), as was median total effective radiation dose (P = 0.105). Upfront CCTA was not associated with higher rates of incidental non-cardiac findings. Conclusions: Initial evaluation of acute chest pain in the ED with CCTA was not associated with an increase in total radiation exposure over a follow-up period of 19 months. CCTA offers a more comprehensive evaluation of multiple thoracic organ systems leading to reduced radiation exposure from non-cardiac thoracic testing and no increase in incidental imaging findings. This may represent an added benefit in this population of patients presenting acutely.

Prospectively ECG-Triggered Sequential Dual-Source Coronary CT Angiography in Patients with Atrial Fibrillation: Influence of Heart Rate on Image Quality and Evaluation of Diagnostic Accuracy.

ObjectivesTo evaluate the effects of mean heart rate (HR) and heart rate variation (HRV) on image quality and diagnostic accuracy of prospectively ECG-triggered sequential dual-source coronary CT angiography (CCTA) in patients with atrial fibrillation (AF).MethodsEighty-five patients (49 women, 36 men; mean age 62.1±9.5 years) with persistent AF underwent prospectively ECG-triggered sequential second-generation dual-source CCTA. Tube current and voltage were adjusted according to body mass index (BMI) and iterative reconstruction was used. Image quality of coronary segments (four-point scale) and presence of significant stenosis (>50%) were evaluated. Diagnostic accuracy was analyzed in 30 of the 85 patients who underwent additional invasive coronary angiography (ICA).ResultsOnly 8 of 1102 (0.7%) segments demonstrated poor image quality. No significant impact on image quality was found for mean HR (94.9±21.8 bpm; r=0.034, p=0.758; F=0.413, p=0.663) or HRV (67.5±22.8 bpm; r=0.097, p=0.377; F=0.111, p=0.895). On per-segment analysis, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 89.7% (26/29), 99.4% (355/357), 92.9% (26/28), and 99.2% (355/358), respectively, with excellent correlation (kappa=0.91) with ICA. Mean effective dose was 3.3±1.0 mSv.ConclusionsProspectively ECG-triggered sequential dual-source CCTA provides diagnostic image quality and good diagnostic accuracy for detection of coronary stenosis in AF patients without significant influence by HR or HRV.

Risk factors of venous thromboembolism in focal segmental glomerulosclerosis with nephrotic syndrome.

Venous thromboembolism (VTE) is an important and potentially life-threatening complication in focal segmental glomerulosclerosis (FSGS). The aim of this study was to investigate the prevalence and predisposing risk factors of venous thromboembolism in patients with FSGS with nephrotic syndrome. A total of 120 FSGS patients with nephrotic syndrome were enrolled in this study. Venous thromboembolism was confirmed by contrast-enhanced dual-source computed tomography angiography or magnetic resonance venography. Potential clinical and laboratory risk factors for VTE were screened. Venous thrombosis was demonstrated in 12 (10 %) patients. Venous thrombosis occurred during the first episode of nephrotic syndrome in 3 patients and during a relapse in 9 patients. Eight patients had a pulmonary embolism, four had a renal vein thrombosis, three had a lower limb deep vein thrombosis, one had a cerebral sinovenous thrombosis, and one had a portal vein thrombosis. The positive predictive value for the D-dimer level was 22.4 % in the patients with FSGS, and the negative predictive value for the D-dimer level was 100 %. Of the screened risk factors, higher hematocrit and relapse of nephrotic syndrome were risk factors for VTE. Other risk factors, such as proteinuria, hypoalbuminemia, platelet count, fibrinogen level, and antithrombin III level, were not risk factors for VTE in patients with FSGS. We found that the prevalence of venous thromboembolism is approximately 10 % in FSGS patients with nephrotic syndrome. Most of the patients had a PE. Hemoconcentration and relapse of nephrotic syndrome were risk factors for the development of VTE in FSGS. Negative D-dimer may exclude venous thromboembolism in patients with nephrotic syndrome.

Detection of coronary artery anomaly in patients with complex congenital heart disease by dual-source CT

Objective To explore the clinical usefulness of low-dose dual-source CT (DSCT) angiography in detecting coronary artery anomaly (CAA) in patients with complex congenital heart disease (CHD). Methods A total of 615 consecutive patients with complex CHD who underwent DSCT angiography between 2008 and 2012 were retrospectively reviewed. According to the ultrasonic results, a total of 312 patients with tetralogy of Fallot (n=176 cases) or double outlet right ventricle (n=72 cases) or pulmonary artery atresia (n=64 cases) were included. Scans were divided into 3 groups: retrospective electrocardiogram (ECG)-triggered spiral scanning in 75 cases, prospective ECG-triggered spiral scanning in 158 cases, and prospective ECG-triggered high-pitch spiral scanning in 79 cases. The subjective image quality was evaluated with a four-point scale by two radiologists. Radiation dose values were calculated. Interobserver agreement in subjective image quality grading was assessed by using Kappa statistics. The scanning groups were compared with the Kruskal-Wallis test. Results The incidence of CAA was 8.0% (25/312) . CAA was detected in 7.9% (14/176) patients with tetralogy of Fallot, 8.3% (6/72) patients with double outlet right ventricle, 7.8% (5/64) patients with pulmonary artery atresia. In 76% (19/25) of the patients, the anomalous vessels were crossing the right ventricular outflow tract (RVOT). Thirty of 312 CT examinations were nondiagnostic (9.6%). Two radiologists acquired good agreement (Kappa=0.72, P<0.01). The median subjective image quality score of three scan groups was 3 (range 1—4). The score in high-pitch spiral scanning group was significantly lower than those in other two groups (H=29.1, P<0.01) . Retrospective ECG-triggered scans had a median dose of 1.19 mSv (range 0.52—3.29 mSv) , prospectively ECG-triggered scans had a median dose of 0.51 mSv (range 0.27—2.13 mSv) , and prospectively ECG-triggered high-pitch spiral scans had a median effective dose of 0.30 mSv (range 0.18—0.62 mSv) . The difference between groups was statistically significant (H=160.0, P<0.01) . Conclusions DSCT angiography is a reliable diagnostic method for the assessment of CAA with complex CHD and low-dose prospectively ECG-triggered DSCT scan is the best choice. Key words: Coronary artery disease; Heart defects, congenital; Tomography, X-ray computed

Association of aortic root calcification severity with the extent of coronary artery calcification assessed by calcium-scoring dual-source computed tomography

PurposeTo investigate the association between aortic root calcification (ARC) and coronary artery calcification (CAC) assessed by coronary artery calcium-scoring dual-source computed tomography (DSCT). Materials and methodsWe retrospectively analyzed 143 consecutive patients who underwent coronary artery calcium-scoring during coronary DSCT angiography. 57 patients had findings of ARC on calcium-scoring scans. ARC volume (ARCV) and Agatston coronary artery calcium score (CACS) were calculated. Chi-square test was used to assess differences of categorical variables between patients with and without ARC. Statistical significances between both groups were assessed with the independent-Sample t test. ResultsCompared with patients without ARC (n=86), patients with ARC (n=57) showed a significantly higher presence of CAC (87.7% vs. 24.4%; P<0.001), and a higher mean CACS (700.6±941.2 vs. 256.4±724.3; P=0.009) in patients with CAC. Patients with a calculated ARCV >40mm3 (n=32) showed significantly higher rates of severe CAC (56.3% vs. 24.0%; P=0.014) compared with patients with an ARCV<40mm3 (n=25). Compared with patients without CAC (n=42), patients with CAC (n=101) showed a significantly higher presence of ARC (83.3% vs. 50.5%; P<0.001) and a higher mean ARCV (95.4±116.2mm3 vs. 29.7±33.0 mm3; P=0.003). Severe CAC (n=24) correlated with an increased mean ARCV (122.3±148.8mm3) compared to patients with minimal to moderate CAC (n=33, mean ARCV: 61.9±64.8mm3; P<0.05). ConclusionsThe extent of ARC is directly associated with the presence and degree of CAC on calcium-scoring scans during coronary DSCT angiography.

Diagnostic accuracy of dual-source CT angiography for evaluation of coronary artery and comparative analysis of the DSCT angiography of the internal carotid artery plaque with the histopathological specimens

The purpose of this study was to investigate the diagnostic accuracy of a dual-source CT (DSCT) coronary angiography in parallel with a CT angiography. On the other hand, we compared the DSCT angiography of the internal carotid artery plaque with the histopathological specimens. Ninety patients underwent DSCT and an invasive coronary angiography (ICA). All segments were analyzed at 60 and 70 % of R-R interval initially. After finding the reconstruction interval, image quality was divided for each coronary segment on the four-point Likert scale. Also, of these patients, 30 cases that had neurological symptoms and carotid arteries also were evaluated. The degree of stenosis was assessed according to the North American Carotid Endarterectomy Trial (NASCET) criteria. A patient-specific analysis revealed that the method sensitivity was 98.59 %, specificity was 94.7 %, positive predictive value (PPV) was 98.57 %, negative predictive value (NPV) was 95 %, and accuracy was 97.7 %. Also, the kappa statistics did show high values in agreement with the histopathological findings (type III k = 0.82, types IV–V = 0.86, type VI = 0.81, type VII = 0.88, and type VIII = 0.67). Our results suggest that the DSCT has a high diagnostic accuracy for the evaluation of CAD and could demonstrate a high correlation between non-invasive imaging findings with DSCT and histopathological specimens.

Dose levels and image quality of second-generation 128-slice dual-source coronary CT angiography in clinical routine.

To compare radiation exposure and image quality of second-generation 128-slice dual-source CT (DSCT) coronary angiography (cCTA) protocols. We retrospectively analyzed data from four groups with 25 patients, each examined by one of the following DSCT cCTA protocols: prospectively ECG-gated high-pitch (group 1) or sequential (group 2) acquisition, retrospectively ECG-gated acquisition in dual-energy (DECT, group 3) or dual-source (group 4) mode. CT dose index volume, dose length product, estimated radiation dose, contrast-to-noise- and signal-to-noise-ratios were compared. Subjective image quality was rated by two observers blinded to the protocols. High-pitch DSCT showed a mean estimated radiation dose of 1.27±0.62mSv, significantly (p<0.01) lower than sequential (2.04±0.94mSv), dual-energy (3.97±1.29mSv) or dual-source (8.11±4.95mSv) acquisition. Image noise showed no statistical difference (p>0.91), ranging from 15.2±4.4 (group 2) up to 24.5±22.0 (group 4). Each protocol showed diagnostic image quality in at least 98.1% of evaluated coronary segments without significant differences (p>0.05). Prospectively ECG-gated DSCT protocols enable cCTA with significant dose reduction and consistently diagnostic image quality. In patients requiring retrospectively ECG-gated DSCT for functional analysis or due to arrhythmia, dual-energy mode should be preferred over dual-source mode as it significantly decreases estimated dose without compromising image quality.

Diagnostic Value of Prospective Electrocardiogram-triggered Dual-source Computed Tomography Angiography for Infants and Children with Interrupted Aortic Arch.

Background:Accurate assessment of intra- as well as extra-cardiac malformations and radiation dosage concerns are especially crucial to infants and children with interrupted aortic arch (IAA). The purpose of this study is to investigate the value of prospective electrocardiogram (ECG)-triggered dual-source computed tomography (DSCT) angiography with low-dosage techniques in the diagnosis of IAA.Methods:Thirteen patients with suspected IAA underwent prospective ECG-triggered DSCT scan and transthoracic echocardiography (TTE). Surgery was performed on all the patients. A five-point scale was used to assess image quality. The diagnostic accuracy of DSCT angiography and TTE was compared with the surgical findings as the reference standard. A nonparametric Chi-square test was used for comparative analysis. P <0.05 was considered as a significant difference. The mean effective radiation dose (ED) was calculated.Results:Diagnostic DSCT images were obtained for all the patients. Thirteen IAA cases with 60 separate cardiovascular anomalies were confirmed by surgical findings. The diagnostic accuracy of TTE and DSCT for total cardiovascular malformations was 93.7% and 97.9% (P > 0.05), and that for extra-cardiac vascular malformations was 92.3% and 99.0% (P < 0.05), respectively. The mean score of image quality was 3.77 ± 0.83. The mean ED was 0.30 ± 0.04 mSv (range from 0.23 mSv to 0.39 mSv).Conclusions:In infants and children with IAA, prospective ECG-triggered DSCT with low radiation exposure and high diagnostic efficiency has higher accuracy compared to TTE in detection of extra-cardiac vascular anomalies.

Abstract 563: Activated Circulating Intermediate Monocytes are Associated with Subclinical Coronary Plaque in Apparently Healthy Middle-Aged Men

Background: The intermediate subset accounts for the smallest percentage of circulating monocytes yet has been associated with chronic inflammatory diseases, including CAD outcomes. It is unknown if activated intermediate monocytes (IM) are associated with coronary plaque at an earlier stage in atherosclerosis, prior to clinical manifestations. Methods: We screened 11 healthy nondiabetic, non statin using, age-matched males for the presence and extent of coronary plaque using advanced dual-source CT angiography. Total coronary plaque (TCP) volumes (mm3) were quantified using a validated automated method and transformed to log(TCP+1). To examine monocyte subsets, whole blood was labeled to exclude non-monocytic cells. Surface CD14, CD16, TLR2, CX3CR1, and CD11b were used to confirm monocyte subsets by flow cytometry with HLA-DRhi as a marker of activation. Results: Mean age was 54±2 (range 49 to 57); 36% were African American, 27% were smokers, and 45% had hypertension. Mean LDL-C was 121±38. The absolute number of circulating activated IM per cu mm was higher in the 6 individuals with coronary plaque compared to the 5 with no plaque (42.6±24.8 vs. 15.6±11.9, p=0.05). In bivariate analysis the number of activated IM was significantly associated with TCP (Figure, r=0.71, p=0.01). These associations were not found with classical and nonclassical monocytes. Conclusion: In a small population of age-matched, nondiabetic apparently healthy middle-aged men not on statin therapy, the number of circulating activated IM was associated with the presence and volume of subclinical coronary plaque. Further investigation of monocyte activation prior to plaque development is ongoing.

Prevalence of Subclinical Coronary Artery Disease in Middle-Aged, Male Marathon Runners Detected by CardiacCT.

To evaluate the prevalence of coronary artery disease (CAD) in middle-aged, male marathon runners using coronary dual source CT angiography (DSCTA). 50 male marathon runners older than 45 years (mean age: 52.7, standard deviation: 5.9 years, range: 45 to 67 years) received DSCTA including calcium scoring (CS) in addition to standard pre-participation screening. Based on standard risk factors, the risk for coronary events was calculated using the PROCAM score. Coronary status was defined using the following system: 1. absence of CAD (CS zero, no coronary plaques) 2. mild coronary atherosclerosis (CS > 0, coronary plaques with luminal narrowing < 50 %), 3. moderate coronary atherosclerosis (CS > 0, luminal narrowing > 50 %), 4. significant CAD (CS > 0, luminal narrowing > 75 %). The mean PROCAM score was 1.85 % (standard deviation = 1.56, range 0.39 to 8.47 %). 26/50 marathon runners had no atherosclerosis. 1 of the remaining 24 participants had significant CAD, 3 had moderate coronary atherosclerosis and 20 had mild coronary atherosclerosis. Treadmill exercise testing was unremarkable in terms of myocardial ischemia in all participants. Age, systolic blood pressure, personal minimum time, family history of cardiovascular disease and PROCAM score were factors associated with an increased risk for coronary atherosclerosis. Coronary atherosclerosis can be detected in almost 50 % of male marathon runners aged older than 45 years. In 24 % of the participants plaques were located in the proximal coronary system. However, only a minority of these persons have obstructive CAD. As expected, treadmill exercise testing failed to detect these persons that possibly have a higher risk for coronary events. • Coronary atherosclerosis can be detected in ~50 % of male marathon runners > 45 years. • Only a minority of these persons have obstructive CAD. • Treadmill exercise testing failed to detect these persons. • Cardiac CT might help to identify athletes with elevated risk for coronary events, especially in persons with a family history of coronary artery.

Clinical Evaluation of Coronary In-Stent Restenosis Using Dual-Source Computed Tomography.

To explore the feasibility of dual-source computed tomography (DSCT) in the evaluation of coronary in-stent restenosis (ISR) by comparing the results of DSCT and selective coronary angiography (CAG). In-stent restenosis examination results from DSCT were compared with those obtained using CAG. Among 173 stents studied, 156 yielded good quality images when evaluated with DSCT. CAG identified 38 ISR cases, while DSCT found 40. Among the 112 stents in the study with an inner diameter ≥3.0mm, CAG identified 29 as having ISR, while DSCT reported the same finding in 30; among the 44 stents with inner diameter <3.0mm, CAG identified ISR in 9, while DSCT found ISR in 10. Stent inner diameter is a key factor influencing the imaging of the stent lumen. DSCT demonstrated a higher negative predictive value in ISR assessment, suggesting that it could replace CAG for assessing the patency of stents with a larger inner diameter (≥3mm).

Application of optimal contrast medium injection protocol for 128-slice dual-source computed tomography in children with Tetralogy of Fallot

To compare the image qualities of different contrast medium injection protocols for 128-slice dual-source computed tomography (DSCT) in children with Tetralogy of Fallot (TOF). A total of 60 patients with TOF were randomly divided into groups A, B and C (n = 20 each). And 128-slice DSCT angiography was performed with sequential mode according to the contrast injection protocols: the volume of contrast medium was 1.2, 1.2 and 1.5 ml/kg and the injection time 10, 12 and 15 s respectively. Contrast medium was followed by a saline bolus for 10 s. Enhancement and noise of ascending aorta, main pulmonary artery, descending aorta and left ventricle were quantified. Signal-to-noise ratio (SNR), dose-length product (DLP) and effective dose (ED) were calculated. The absolute difference of left and right ventricular attenuations was calculated to represent the image uniformity. Subjective image quality was assessed by two radiologists in consensus. No significant difference existed in attenuation or SNR between three groups in the same evaluated anatomic regions. No significant difference existed in image quality of heart chamber and great vessels. The image uniformity (81 ± 65) and subjective image quality of artifacts of superior vena cava were significantly better in group B than those in groups A and C (179 ± 178, 106 ± 66, P < 0.05). The contrast medium injection protocol of 1.2 ml/kg volume contrast medium injected within 12 s may enhance the image quality of 128-slice dual-source CT in children with TOF.

Coronary artery fistula in adults: evaluation with dual-source CT coronary angiography.

To evaluate the clinical value of dual-source CT (DSCT) coronary angiography in the diagnosis of coronary artery fistula (CAF) in adults. A large cohort of 17,548 patients, who underwent DSCT coronary angiography in our hospital between January 2008 and October 2013, were retrospectively reviewed for CAF. The origin, course and drainage site of CAF and coexisting abnormalities were analysed. The conventional angiography results, treatments and follow-up DSCT images were also evaluated. A total of 33 CAFs from 17,548 patients were detected. The incidence of CAF was 0.19% by DSCT. CAF originating from the left coronary artery (LCA) was found in 14 (42.4%) patients, from right coronary artery (RCA) in 4 (12.1%) cases and from both LCA and RCA in 15 (45.5%) patients. The pulmonary artery was the most common site of drainage (28/33, 84.8%). 8 of the 33 (24.2%) cases were associated with aneurysms. Six cases were associated with coronary artery atherosclerosis. Four patients underwent conventional angiography. Coronary-pulmonary artery fistula in adults was found more often than in previous studies. CAF commonly originates from LCA or both LCA and RCA in adults. DSCT is a robust tool for investigating the origin, course and drainage site of CAF and coexistent abnormalities. A large adult patient cohort who underwent DSCT angiography was reviewed to assess CAFs. Coronary-pulmonary artery fistula in adults was found more often than in previous studies. CAF was observed to originate from the LCA or both coronary arteries in adults. DSCT could clearly depict the fistula origin, course, drainage site and coexisting abnormalities. Conventional angiography results, treatments and follow-up DSCT images were analysed.

Dual-Source Dual-Energy CT Angiography of the Supra-Aortic Arteries with Tin Filter: Impact of Tube Voltage Selection

Automatic bone and plaque subtraction (BPS) in computed tomographic angiographic (CTA) examinations using dual-energy CT (DECT) remains challenging because of beam-hardening artifacts in the shoulder region and close proximity of the internal carotid artery to the base of the skull. The selection of the tube voltage combination in dual-source CT influences the spectral separation and the susceptibility for artifacts. The purpose of this study was to assess which tube voltage combination leads to an optimal image quality of head and neck DECT angiograms after bone subtraction. Fifty-one patients received tin-filter-enhanced DECT angiograms of the supra-aortic arteries using two voltage protocols: 24 patients were studied using 80/Sn140 kV and 27 using a 100/Sn140 kV protocol, both protocols with an additional tin filter. A commercially available DE-CTA BPS algorithm was used. Artificial vessel erosions in BPS maximum intensity projections (four-level Likert scale with CTA source data as reference) and vessel signal-to-noise ratio (SNR) were assessed in the level of the shoulders and the base of the skull in each patient and compared. At the level of the shoulder, 100/Sn140 kV achieved higher SNR (23.4 ± 6.4 at 80/Sn140 kV vs. 35.1 ± 11.8 at 100/Sn140 kV; P < .0001) with less erosions (erosion score 3.9 ± 0.4 in 80/Sn140 kV vs. 2.1 ± 1.3 in 100/Sn140 kV; P < .0001) than 80/Sn140 kV. At the level of the skull base, erosion scores and objective image quality of arterial segments were comparable with both protocols (P = .14). The 100/Sn140 kV protocol achieved more favorable results for BPS of the supra-aortic arteries than the 80/Sn140 kV protocol.

High-pitch, low-voltage and low-iodine-concentration CT angiography of aorta: assessment of image quality and radiation dose with iterative reconstruction.

ObjectiveTo assess the image quality of aorta obtained by dual-source computed tomography angiography (DSCTA), performed with high pitch, low tube voltage, and low iodine concentration contrast medium (CM) with images reconstructed using iterative reconstruction (IR).MethodsOne hundred patients randomly allocated to receive one of two types of CM underwent DSCTA with the electrocardiogram-triggered Flash protocol. In the low-iodine group, 50 patients received CM containing 270 mg I/mL and were scanned at low tube voltage (100 kVp). In the high-iodine CM group, 50 patients received CM containing 370 mg I/mL and were scanned at the tube voltage (120 kVp). The filtered back projection (FBP) algorithm was used for reconstruction in both groups. In addition, the IR algorithm was used in the low-iodine group. Image quality of the aorta was analyzed subjectively by a 3-point grading scale and objectively by measuring the CT attenuation in terms of the signal- and contrast-to-noise ratios (SNR and CNR, respectively). Radiation and CM doses were compared.ResultsThe CT attenuation, subjective image quality assessment, SNR, and CNR of various aortic regions of interest did not differ significantly between two groups. In the low-iodine group, images reconstructed by FBP and IR demonstrated significant differences in image noise, SNR, and CNR (p<0.05). The low-iodine group resulted in 34.3% less radiation (4.4 ± 0.5 mSv) than the high-iodine group (6.7 ± 0.6 mSv), and 27.3% less iodine weight (20.36 ± 2.65 g) than the high-iodine group (28 ± 1.98 g). Observers exhibited excellent agreement on the aortic image quality scores (κ = 0.904).ConclusionsCT images of aorta could be obtained within 2 s by using a DSCT Flash protocol with low tube voltage, IR, and low-iodine-concentration CM. Appropriate contrast enhancement was achieved while maintaining good image quality and decreasing the radiation and iodine doses.

High Pitch Dual-Source Whole Aorta CT Angiography in the Detection of Coronary Arteries: A Feasibility Study of Using Iodixanol 270 and 100 kVp with Iterative Reconstruction

Discipline of Medical Imaging, Department of Imaging and App lied Physics, Curtin University, Perth, 6102, AustraliaTo assess the feasibility of detecting coronary arteries through high-pitch dual-source computed tomography(DSCT) thoracoabdominal angiography when using low-concentration contrast medium, low tube voltage, anditerative reconstruction. One hundred patients undergoing DSCT angiography with high-pitch data acquisitionmode were prospectively enrolled in this study. F ifty patients were assigned to receive Iodixanol 270 andscanned using the low tube voltage (100 kVp) technique and iterative reconstruction, while another Þfty patientswere assigned to Iopamidol 370 and scanned under the conventional tube voltage (120 kVp) with the imageswere reconstructed with Þltered back projection. Bo th subjective and objective assessment of image qualitywas performed and compared between the two groups by measuring the image noise, signal-to-noise ratio andcontrast-to-noise ratio in the coronary arteries. Diagnostic images were obtained for 1267 of the 1325 segments(95.6%). No signiÞcant differences in image quality wer e found between patients given Iodixanol 270 and Iopami-dol 370. The effective dose and contrast medium dose were 4.4 ± 0.5 mSv and 6.7 ± 0.6 mSv, 20.36 ± 2.65 gand 28 ± 1.98 g, corresponding to the Iodixanol 270 and Iopam idol 370 groups, respectively, with 34.3% dosereduction achieved in the low contrast medium Iodix anol 270 group. High-pitch DSCT angiography of the tho-racoabdominal aorta utilizing low iodine concentration contrast medium (Iodixanol 270), low tube voltage, anditerative reconstruction is a feasible protocol with signiÞcant reduction in r adiation dose and contrast medium,without compromising image quality.

Dual-source dual-energy CT angiography with virtual non-enhanced images and iodine map for active gastrointestinal bleeding: Image quality, radiation dose and diagnostic performance

ObjectivesTo evaluate the clinical feasibility of dual-source dual-energy CT angiography (DSDECTA) with virtual non-enhanced images and iodine map for active gastrointestinal bleeding (GIB). MethodsFrom June 2010 to December 2012, 112 consecutive patients with clinical signs of active GIB underwent DSDECTA with true non-enhanced (TNE), arterial phase with single-source mode, and portal-venous phase with dual-energy mode (100kVp/230mAs and Sn 140kVp/178mAs). Virtual non-enhanced CT (VNE) image sets and iodine map were reformatted from ‘Liver VNC’ software. The mean CT number, noise, signal to noise ratio (SNR), image quality and radiation dose were compared between TNE and VNE image sets. Two radiologists, blinded to clinical data, interpreted images from DSDECTA with TNE (protocol 1), and DSDECTA with VNE and iodine map (protocol 2) respectively, with discordant interpretation resolved by consensus. The standards of reference included digital subtraction angiography, endoscopy, surgery, or final pathology reports. Receiver–operating characteristic (ROC) analysis was undertaken and the area under the curve (AUC) calculated for CT protocols 1 and 2, respectively. ResultsThere was no significant difference in mean CT numbers of all organs (including liver, pancreas, spleen, kidney, abdominal aorta, and psoas muscle) (P>0.05). Lower noise and higher SNR were found on VNE images than TNE images (P<0.05). Image quality of VNE was lower than that of TNE without significant difference (P>0.05). The active GIB source was identified in 84 patients, 83 (83/84, 98.8%) of which were confirmed by one or more reference standard. The AUC was 0.935±0.027 and 0.947±0.026 for protocols 1 and 2, respectively. There was no significant difference between protocols 1 and 2 for diagnostic performance (Z=1.672, P>0.05). The radiation dose reduction achieved by omitting the TNE acquisition was (30.11±6.32)%. ConclusionDSDECTA with arterial phase with single-source mode, portal-venous phase with dual-energy mode and post-processing VNE image sets and iodine map could act as an accurate screening method for detection and localization of active GIB with lower radiation dose.

Giant coronary aneurysm caused by Kawasaki disease: consistency between catheter angiography and electrocardiogram gated dual-source computed tomography angiography.

We present the case of a 5-year-old child with coronary complications due to Kawasaki disease; this patient unintentionally underwent both dual-source computed tomography (DSCT) coronary angiography and invasive coronary angiographic examination in 2 months. This case highlights the strong consistency of the results between DSCT coronary angiography and invasive coronary angiography. Compared to conventional invasive coronary angiography, DSCT coronary angiography offered additional advantages such as minimal invasiveness and less radiation exposure.

Application of Prospective ECG-Gated High-Pitch 128-Slice Dual-Source CT Angiography in the Diagnosis of Congenital Extracardiac Vascular Anomalies in Infants and Children

PurposeTo investigate the value of prospective ECG-gated high-pitch 128-slice dual-source CT (DSCT) angiography in the diagnosis of congenital extracardiac vascular anomalies in infants and children in comparison with transthoracic echocardiography (TTE).MethodsEighty consecutive infants or children clinically diagnosed of congenital heart disease and suspected with extracardiac vascular anomaly were enrolled, and 75 patients were finally included in this prospective study. All patients underwent prospective ECG-gated high-pitch DSCT angiography after TTE with an interval of 1–7 days. The diagnostic accuracy and sensitivity of high-pitch DSCT angiography and TTE were compared according to the surgical/CCA findings. The image quality of DSCT was assessed using a five-point scale. The effective radiation dose (ED) was calculated.ResultsA total of 17 congenital heart diseases and 162 separate extracardiac vascular anomalies were confirmed by surgical/CCA findings in 75 patients. The diagnostic accuracy of high-pitch DSCT angiography and TTE was 99.67% and 97.89%, respectively. The sensitivity of high-pitch DSCT angiography and TTE was 97.53% and 79.62%, respectively. There was significant difference regarding to the diagnostic accuracy and the sensitivity between high-pitch DSCT angiography and TTE (χ2 = 23.561 and 28.013, P<0.05). The agreement on the image quality scoring of DSCT between the two observers was excellent (κ = 0.81), and the mean score of image quality was 4.1±0.7. The mean ED of DSCT was 0.29±0.08 mSv.ConclusionsProspective ECG-gated high-pitch 128-slice DSCT angiography with low radiation dose and high diagnostic accuracy has higher sensitivity compared to TTE in the detection of congenital extracardiac vascular anomalies in infants and children.