Coronary CT angiography in calcified coronary plaques: Comparison of diagnostic accuracy between bifurcation angle measurement and coronary lumen assessment for diagnosing significant coronary stenosis.

BACKGROUND: To investigate the diagnostic value of coronary CT angiography (CCTA) by bifurcation angle measurement in the assessment of calcified plaques compared to conventional coronary lumen analysis. METHODS: Fifty-three patients with calcified plaques identified on CCTA in the left coronary artery were included in the study. Minimal lumen diameter (MLD) and bifurcation angle between the left anterior descending (LAD) and left circumflex (LCx) arteries were measured and compared between CCTA and invasive coronary angiography (ICA), while the areas under the curves (AUCs) by receiver-operating characteristic curve analysis (ROC) were compared between CCTA and ICA with regard to the diagnostic value of using bifurcation angle as a criterion. RESULTS: On a per-vessel assessment, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) and 95% confidence interval (CI) with the use of bifurcation angle for determining coronary stenosis were 100% (86%, 100%), 79% (59%, 92%), 81% (62%, 92%), and 100% (85%, 100%) for CCTA, and 100% (86%, 100%), 82% (63%, 94%), 83% (65%, 94%), and 100% (85%, 100%) for ICA, respectively. While the sensitivity and NPV remained unchanged, the specificity and PPV of CCTA by MLD were 33% (21%, 47%) and 43% (31%, 56%). The AUCs by ROC curve analysis for CCTA and ICA bifurcation angle measurements demonstrated no significant difference (p>0.05, 0.79 vs 0.86, and 0.70 vs 0.68 at the LAD and LCx assessment, respectively). CONCLUSION: Coronary CT angiography by bifurcation angle measurement shows significant improvement in the diagnosis of calcified plaques with diagnostic value comparable to invasive coronary angiography

Noninvasive physiologic assessment of coronary stenoses using cardiac CT

Coronary CT angiography (CCTA) has become an important non-invasive imaging modality in the diagnosis of coronary artery disease (CAD). CCTA enables accurate evaluation of coronary artery stenosis. However, CCTA provides limited information on the physiological significance of stenotic lesions. A noninvasive ‘one-stop-shop’ diagnostic test that can provide both anatomical and functional significance of stenotic lesions would be beneficial in the diagnosis and management of CAD. Recently, with the introduction of novel techniques such as myocardial CT perfusion, CT-derived fractional flow reserve (FFRCT), and transluminal attenuation gradient (TAG), CCTA has emerged as a non-invasive method for the assessment of both anatomy of coronary lesions and its physiological consequences during a single study. This review provides an overview of the current status of new CT techniques for the physiologic assessments of CAD

Clinical evaluation of new automatic coronary specific best cardiac phase selection algortithm for single-beat coronary CT angiography

The aim of this study was to evaluate the workflow efficiency of a new automatic coronary-specific reconstruction technique (Smart Phase, GE Healthcare—SP) for selection of the best cardiac phase with least coronary motion when compared with expert manual selection (MS) of best phase in patients with high heart rate. A total of 46 patients with heart rates above 75 bpm who underwent single beat coronary computed tomography angiography (CCTA) were enrolled in this study. CCTA of all subjects were performed on a 256-detector row CT scanner (Revolution CT, GE Healthcare, Waukesha, Wisconsin, US). With the SP technique, the acquired phase range was automatically searched in 2% phase intervals during the reconstruction process to determine the optimal phase for coronary assessment, while for routine expert MS, reconstructions were performed at 5% intervals and a best phase was manually determined. The reconstruction and review times were recorded to measure the workflow efficiency for each method. Two reviewers subjectively assessed image quality for each coronary artery in the MS and SP reconstruction volumes using a 4-point grading scale. The average HR of the enrolled patients was 91.1±19.0bpm. A total of 204 vessels were assessed. The subjective image quality using SP was comparable to that of the MS, 1.45±0.85 vs 1.43±0.81 respectively (p = 0.88). The average time was 246 seconds for the manual best phase selection, and 98 seconds for the SP selection, resulting in average time saving of 148 seconds (60%) with use of the SP algorithm. The coronary specific automatic cardiac best phase selection technique (Smart Phase) improves clinical workflow in high heart rate patients and provides image quality comparable with manual cardiac best phase selection. Reconstruction of single-beat CCTA exams with SP can benefit the users with less experienced in CCTA image interpretation

320-row CT renal perfusion imaging in patients with aortic dissection: A preliminary study

Objective: To investigate the clinical value of renal perfusion imaging in patients with aortic dissection (AD) using 320-row computed tomography (CT), and to determine the relationship between renal CT perfusion imaging and various factors of aortic dissection. Methods: Forty-three patients with AD who underwent 320-row CT renal perfusion before operation were prospectively enrolled in this study. Diagnosis of AD was confirmed by transthoracic echocardiography. Blood flow (BF) of bilateral renal perfusion was measured and analyzed. CT perfusion imaging signs of AD in relation to the type of AD, number of entry tears and the false lumen thrombus were observed and compared. Results: The BF values of patients with type A AD were significantly lower than those of patients with type B AD (P = 0.004). No significant difference was found in the BF between different numbers of intimal tears (P = 0.288), but BF values were significantly higher in cases with a false lumen without thrombus and renal arteries arising from the true lumen than in those with thrombus (P = 0.036). The BF values measured between the true lumen, false lumen and overriding groups were different (P = 0.02), with the true lumen group having the highest. Also, the difference in BF values between true lumen and false lumen groups was statistically significant (P = 0.016), while no statistical significance was found in the other two groups (P > 0.05). The larger the size of intimal entry tears, the greater the BF values (P = 0.044). Conclusions: This study shows a direct correlation between renal CT perfusion changes and AD, with the size, number of intimal tears, different types of AD, different renal artery origins and false lumen thrombosis, significantly affecting the perfusion values

3D CT Angiography of Infrarenal Abdominal Aortic Aneurysm with Associated Ectopic Pelvic Kidney: A Case Report of Rare Concomitance

The abdominal aortic aneurysm (AAA) associated with congenital pelvic kidney is a rare clinical finding. We present a case of an infrarenal AAA with associated congenital left pelvic kidney followed up for 5 years, which was managed by regular surveillance. We describe this case to assist physicians and radiologists to recognize small aneurysmsby computed tomography angiography (CTA) with low radiation dose and low iodine dose. To the best of our knowledge,this case is the first report by using CTA with the combination of low-concentration contrast medium, low radiation doseand iterative reconstruction

Cardiac magnetic resonance analysis of left atrium function in patients with pre-apical hypertrophic cardiomyopathy

Background: Patients presenting with unexplained T wave inversion on electrocardiogram combined with thickened left ventricular apex but less than 15 mm had been proposed as a preclinical scope of apical hypertrophy cardiomyopathy (pre-ApHCM). However, analysis of left atrial (LA) function in these patients has not been studied. This study aims to evaluate the LA function in pre-ApHCM patients and compare it with patients with ApHCM using cardiac magnetic resonance (CMR) imaging. Methods: In this retrospective case-control study, a total of 3,593 CMR reports from Beijing Anzhen Hospital, Capital Medical University, China were reviewed. Finally, 31 pre-ApHCM patients were identified and 40 ApHCM and 31 normal controls were included for comparison. LA volumetric and strain were analyzed by CMR. Two-tailed one-way ANOVA was used to analyze the difference of three groups. Pearson correlation test was used for correlation analysis. Results: All of the volumetric parameters in pre-ApHCM group were higher than those in control group. LA reservoir (LA total EF, εs) and conduit function (LA passive EF, εe) parameters, were significantly different among the three groups, which were the lowest in the ApHCM group, intermediate in the pre-ApHCM group, and the highest in the control group ((all P<0.001). Compared with the control group, the LA booster pump function, both the booster EF and booster pump strain (εa) in ApHCM were impaired (P=0.003 and P=0.002 respectively). Meanwhile, only the εa was impaired (P=0.016) while LA booster EF was not (P=0.064) in the pre-ApHCM group, neither εa nor the booster EF show difference between the ApHCM and pre-ApHCM (P=0.272 and P=0.518 respectively). Conclusions: LA function features in pre-ApHCM patients were similar to ApHCM but different from the normal controls. In pre-ApHCM and ApHCM patients, LA reservoir and conduit function impaired earlier before left atrium enlarged and decreased progressively as apex thickens. These findings may help to understand the LA functional change from pre-ApHCM to ApHCM, and to detect subclinical changes in patients with pre-ApHCM before overt hypertrophy or clinical symptoms develop

Diagnostic performance of 256-row detector coronary CT angiography in patients with high heart rates within a single cardiac cycle: a preliminary study

AIM: To evaluate the image quality and diagnostic performance of coronary computed tomography angiography (CCTA) in patients with high heart rate within a single cardiac cycle using a 256-row detector CT system. MATERIALS AND METHODS: Eighty-four consecutive symptomatic patients (mean age 60.4 9.1 years, 52 men) with suspected coronary artery disease and heart rate 75 beats/min undergoing CCTA and invasive coronary angiography (ICA) were enrolled retrospectively. Prospective electrocardiography (ECG)-triggered volume CCTA within a single cardiac cycle was performed using a 256-row, 16 cm detector CT system (Revolution CT, GE Healthcare) using automated tube voltage selection (kV Assist selecting 100 or 120 kV) and tube current modulation (Smart mA) techniques, with images reconstructed using 50% of adaptive statistical iterative reconstruction-V (ASiR-V). The image quality of coronary artery segments was evaluated by two reviewers using a four-point scale based on 18-segment model. The diagnostic accuracy of CCTA to detect 50% stenosis on ICA was analysed. The sensitivity, specificity, positive predictive value, and negative predictive value of CCTA to detect a 50% diameter stenosis on ICA were calculated from the chi-squared test of the contingency table on a per-segment, per-vessel, and per-patient basis. RESULTS: The body mass index was 25.6 3.5 kg/m2; the HR was 82.8 7.9 beats/min, and the mean HR variability was 8.3 4.8 beats/min. All of the coronary artery segments, 98.9% (1044/ 1056) of coronary segments were rated as having diagnostic image quality. The diagnostic sensitivity, specificity, positive predictive value, and negative predictive value of CCTA, were 91.5%, 95.6%, 77.7%, and 98.5% on a per-segment basis; 95.2%, 93.5%, 87%, and 97.7% on a pervessel basis; 100%, 85.7%, 93.3%, and 100% on per-patient basis, respectively. The mean effective dose was 1.9 1 mSv. CONCLUSIONS: CCTA using a 256-detector row CT with the snapshot freeze (SSF) technique can be performed in a single cardiac cycle with acquisition of images with high diagnostic value and low radiation dose in patients with high heart rates

Comparison of Different Thoracic Aortic Wall Characteristics for Assessment of Disease Activity in Takayasu Arteritis: A Quantitative Study with 3.0 T Magnetic Resonance Imaging

Background: Determination of disease activity in Takayasu arteritis (TAK) is crucial for clinical management but challenging. The value of different magnetic resonance imaging (MRI) characteristics for the assessment of disease activity remains unclear. This study investigated the imaging findings of the thoracic aortic wall and elasticity by using a comprehensive 3.0 T MRI protocol. Methods: We prospectively enrolled 52 consecutive TAK patients. TAK activity was recorded according to the ITAS2010. All the patients underwent thoracic aortic MRI. The luminal morphology of the thoracic aorta and its main branches were quantitatively evaluated using a contrast-enhanced magnetic resonance angiography (MRA) sequence. The maximum wall thickness of the thoracic aorta, postcontrast enhancement ratio, and aortic wall edema were analyzed in each patient through pre- and post-enhanced T1-weighted and T2-weighted imaging. Pulse-wave velocity (PWV) of the thoracic aorta was calculated using a four-dimensional flow technique. Results: The majority of the 52 patients had type V disease (34.62%, 18/52). Among all the MRI indicators of the thoracic aorta, the area under the curve was the largest for the maximal wall thickness (0.804, 95% confidence interval [CI] = 0.667–0.941). The maximal wall thickness (93.33%, 95% CI = 68.1%–99.8%) exhibited the highest sensitivity with a cutoff value of 3.12 mm. Wall edema (84.00%, 95% CI = 63.9%–95.5%) presented the highest specificity. A positive correlation was noted between PWV and patients’ age (r = 0.54, p < 0.001), disease duration (r = 0.52, p < 0.001), and the maximum wall thickness (r = 0.45, p = 0.001). Conclusions: MRI enabled the comprehensive assessment of aortic wall morphology and functional markers for TAK disease activity. Aortic maximal wall thickness was the most accurate indicator of TAK activity. The early phase was superior to the delay phase for aortic wall enhancement analysis for assessing TAK activity

Optimal scanning protocols of 64-slice CT angiography in coronary artery stents: An in vitro phantom study

Purpose: The purpose of the studywas to investigate the optimal scanning protocol of 64-slice CT angiographyfor assessment of coronary artery stents based on a phantom study.Materials and methods: Coronary stents with a diameter of 2.5mm was implanted in thin plastic tubeswith an inner diameter of 3.0mm to simulate a coronary artery. The tubes were filled with iodinatedcontrast medium diluted to 178HU, closed at both ends and positioned in a plastic container filled withvegetable oil (-70 to -100 HU). A series of scans were performed with a 64-slice CT scanner with thefollowing protocols: section thickness: 0.67mm, 1.0mm, 1.5mm, 2.0mm, pitch value: 0.2, 0.3, 0.5 andreconstruction interval of 50% overlap of the section thickness. 2D axial and multiplanar reformattedimageswere generated to assess the visibility of stent lumen, while virtual intravascular endoscopy (VIE)was reconstructed to evaluate the artery wall and stent surface.Results: Our results showed that a scanning protocol of 1.0mmslice thickness with a pitch of 0.3 producedacceptable images with best demonstration of the intrastent lumen and stent surface with minimal imagenoise or artifacts. In contrast, submillimeter scans with 0.67mm resulted in moderate artifacts whichaffected visualization of the coronary lumen, in addition to the increased noise. When the section thicknessincreased to 1.5mmand 2.0mm, visualization of the arterywall and stent surfacewas compromised,although the intrastent lumen was still visible.Conclusion: Our in vitro study suggested that a scanning protocol of 1.0mm section thickness with pitchof 0.3 is the optimal protocol for evaluation of coronary artery stents as it allows generation of acceptableimages with better visualization of stent lumen, stent surface and coronary artery wall

Myocardial extracellular volume fraction analysis in doxorubicin-induced beagle models: comparison of dual-energy CT with equilibrium contrast-enhanced single-energy CT

Background: Dual-energy CT (DECT) permits the simultaneous operation of two different kV levels, providing a potential method toward the assessment of diffuse myocardial fibrosis. The purpose of this study was to determine the accuracy of DECT for evaluation of the myocardial extracellular volume (ECV) fraction in comparison with single-energy CT (SECT). Methods: Myocardial ECV was quantified in fifteen dogs using DECT and dynamic equilibrium SECT before and after doxorubicin administration. Cardiac magnetic resonance imaging (CMRI) was used to assess myocardial function. The histological collagen volume fraction (CVF) was calculated as the gold standard. The Bland-Altman analysis was performed to compare the agreement between DECT-ECV and SECTECV. The association among ECV values derived from DECT and SECT, CVF, and left ventricular ejection fraction (LVEF) were determined by correlation analysis. The variations of these values were evaluated using repeated ANOVA. Results: The DECT- and SECT-ECV were increased with the elongation of modeling time (pre-modeling vs. 16-week models vs. 24-week models: DECT-ECV 24.1%±1.1%, 35.1%±1.3% and 37.6%±1.4%; SECTECV 22.9%±0.8%, 33.6%±1.2% and 36.3%±1.0%; n=30 in per-subject analysis, all P<0.05). Both ECV values of DECT and SECT correlated well with the histological CVF results (R=0.935 and 0.952 for the DECT-ECV and SECT-ECV; all P<0.001; n=13). Bland-Altman plots showed no significant differences between DECT- and SECT-ECV. Conclusions: DECT-ECV correlated well with both SECT-ECV and histology, showing the feasibility of DECT in evaluating doxorubicin-induced diffuse myocardial interstitial fibrosis