Delineation Of Coronary Arteries Research Articles

Role of CT coronary Angiography in Delineating the anatomic variations of the coronary arteries.

Background: MSCT-CA have been shown promising results, regarding detection of coronary artery disease, as well as alternative tool for interventional coronary procedures, MSCT-CA is currently considered the ideal tool to three dimensionally visualize the complex and tortuous anatomy of coronary arteries.Before coronary revascularization procedures, precise evaluation and description of the coronary artery tree is greatly needed by MSCT-CA. Aim : To assess the role of multi-detector computed tomography coronary angiography with multi-planar reformation and three-dimensional reconstruction in evaluation of anatomic variations of coronary arteries.Method: This study was carried out at radiodiagnosis department, Zagazig university hospitals, A total number of 87 patients with normal heart rate were scheduled for elective multi-detector CT coronary angiography in the period from June 2018 to February 2019. Result: Our study reported coronary dominance was found to be right sided in 83.3 %, left sided in 6.7 % and co-dominant in 10 % of our study group. And LMA branching pattern shows that type IV of LAD (36.7%)was commonest variant and also variable number of diagonals were observed.On the other hands RCA branching pattern shows that one AM branch was been in 73.3%, Regarding the second variant of RCA is shepherd’s crook coronary artery is noted 3.3% of cases, and also conus artery originated from proximal RCA seen in (58.3%). Conclusion: This study has shown that CT coronary angiography is an excellent non-invasive modality in diagnosis and delineation of coronary arteries and can offer valuable information about the normal variants of the coronaries.

CT Coronary Angiography Studies After a Mean Follow-up of 3.8 Years in Children With Kawasaki Disease and Spontaneous Defervescence.

Background: There is paucity of literature on follow-up of children with Kawasaki disease (KD) who have spontaneous defervescence during the acute stage and do not receive intravenous immunoglobulin. We report herein the role of computed tomography coronary angiography (CTCA) as an imaging modality in such situations.Methods: This prospective observational study was carried out during the period January 2016–June 2017. Children underwent CTCA on 128-slice Dual Source CT (DSCT) scanner (Somatom Definition Flash, Siemens; Germany), and 2D-echocardiography on the same day.Results: Mean age at time of diagnosis was 6.52 ± 3.13 years; range 2–14 years. Mean age at time of study was 11.03 ± 5.10 years; range 3.75–23.30 years. Mean interval between diagnosis of KD and time of present study was 3.84 ± 2.27 years. None of the patients showed any coronary artery abnormalities on either 2D-echocardiography or CTCA. While assessment of proximal segments of left main coronary artery, proximal right coronary artery, and left anterior descending artery was comparable on both 2D-echocardiography and CTCA, left circumflex artery, and distal right coronary artery could be clearly visualized only on CTCA.Conclusion: In our experience, patients with KD who have spontaneous defervescence during the acute stage and do not receive IVIg may not have significant long-term coronary sequelae. CTCA is a useful imaging modality for delineation of coronary artery in patients with KD on long term follow-up especially in older children with thick chest walls and poor acoustic windows.

Multi-phase coronary magnetic resonance angiography improves delineation of coronary arteries.

AbstractBackgroundCoronary artery magnetic resonance angiography (CMRA) is a robust tool for delineation of the coronary artery anatomy. In order to overcome the issue of visual delineation of the ...

Photon-Counting CT: High-Resolution Imaging of Coronary Stents.

The aim of this study was to investigate computed tomography (CT) imaging characteristics of coronary stents using a novel photon-counting detector (PCD) in comparison with a conventional energy-integrating detector (EID). In this in vitro study, 18 different coronary stents were expanded in plastic tubes of 3 mm diameter, were filled with contrast agent (diluted to an attenuation of 250 Hounsfield units [HU] at 120 kVp), and were sealed. Stents were placed in an oil-filled custom phantom calibrated to an attenuation of -100 HU at 120 kVp for resembling pericardial fat. The phantom was positioned in the gantry at 2 different angles at 0 degree and 90 degrees relative to the z axis, and was imaged in a research dual-source PCD-CT scanner. Detector subsystem "A" used a standard 64-row EID, while detector subsystem "B" used a PCD, allowing high-resolution scanning (detector pixel-size 0.250 × 0.250 mm in the isocenter). Images were obtained from both detector systems at identical tube voltage (100 kVp) and tube current-time product (100 mA), and were both reconstructed using a typical convolution kernel for stent imaging (B46f) and using the same reconstruction parameters. Two independent, blinded readers evaluated in-stent visibility and measured noise, intraluminal stent diameter, and in-stent attenuation for each detector subsystem. Differences in noise, intraluminal stent diameter, and in-stent attenuation where tested using a paired t test; differences in subjective in-stent visibility were evaluated using a Wilcoxon signed-rank test. Best results for in-stent visibility, noise, intraluminal stent diameter, and in-stent attenuation in EID and PCD were observed at 0-degree phantom position along the z axis, suggesting higher in-plane compared with through-plane resolution. Subjective in-stent visibility was superior in coronary stent images obtained from PCD compared with EID (P < 0.001). Mean in-stent diameter was 28.8% and 8.4% greater in PCD (0.85 ± 0.24 mm; 0.83 ± 0.14 mm) as compared with EID acquisitions (0.66 ± 0.21 mm; 0.76 ± 0.13 mm) for both 0-degree and 90-degree phantom positions, respectively. Average noise was significantly lower (P < 0.001) for PCD (5 ± 0.2 HU) compared with EID (8.3 ± 0.2 HU). The increase in in-stent attenuation (0 degree: Δ 245 ± 163 HU vs Δ 156.5 ± 126 HU; P = 0.006; 90 degrees: Δ 194 ± 141 HU vs Δ 126 ± 78 HU; P = 0.001) was significantly lower for PCD compared with EID acquisitions. At matched CT scan protocol settings and identical image reconstruction parameters, the PCD yields superior in-stent lumen delineation of coronary artery stents as compared with conventional EID arrays.

Utility of cardiac computed tomography scanning in the diagnosis and pre-operative evaluation of patients with infective endocarditis.

Transesophageal echocardiography (TEE) is the gold standard imaging study used in the diagnosis of infective endocarditis (IE). Computed tomography angiography (CTA) has undergone rapid advancement as a cardiac imaging technique and has previously shown promise in small non-randomized studies for evaluation of IE. We hypothesized that cardiac CTA would perform similarly to TEE in the detection of endocarditic lesions and that there would be no difference in clinical outcomes whether the coronary arteries were evaluated by CTA or invasive coronary angiography (ICA). 255 adults who underwent surgery for IE at the Mayo Clinic Rochester between January 1, 2006 and June 1, 2014 were identified retrospectively. 251 patients underwent TEE and 34 patients underwent cardiac CTA. TEE had statistically higher detection of vegetations (95.6 vs. 70.0%, p < 0.0001) and leaflet perforations (81.3 vs. 42.9%, p = 0.02) as compared to cardiac CTA. For detection of abscess/pseudoaneurysm TEE had a similar sensitivity to cardiac CTA (90.5 vs. 78.4%, p = 0.21). There was no significant difference in peri-operative outcomes whether coronary arteries were evaluated by CTA or ICA. The greatest advantage of cardiac CT in the setting of IE is its ability to couple the detection of complex cardiac anatomic abnormalities with coronary artery delineation, serving two important components of the diagnostic evaluation, particularly among patients who will require surgical intervention due to IE complications. Cardiac CTA may be considered as an alternate coronary artery imaging modality in IE patients with low to intermediate risk of disease but meet guideline recommendations for coronary artery imaging.

Automatic and Effective Delineation of Coronary Arteries from CTA Data Using Two-Way Active Contour Model

Automatic and Effective Delineation of Coronary Arteries from CTA Data Using Two-Way Active Contour Model

Robust seed detection for coronary arteries segmentation using thresholded Frangi response

Automatic detection of initial seed points has become an essential step towards delineating coronary arteries in coronary computed tomography angiography (CCTA) images due to image inhomogeneity and other factors. Most coronary segmentation algorithms require user interaction for seed point selection, which may lead to erroneous segmentation. In this study, we present an improved technique of seed detection for coronary segmentation using a thresholded Frangi response. Before computing region of interest (ROI), the proposed method first computes the Frangi response of the complete CCTA volume, followed by thresholding with respect to quantile and median values, and then the ROI selection procedure is applied. Further, this procedure is joined with a feature that is built according to the resemblance among consecutive orthogonal cross-sections. The proposed method was evaluated on nine clinical datasets, and the proposed framework automatically detected coronary seeds accurately and can be used for an accurate delineation of coronary arteries. The obtained results were compared qualitatively and quantitatively by a radiologist, and the proposed method outperformed the previous method with an improvement of 45.9%.

Adaptive particle filtering for coronary artery segmentation from 3D CT angiograms

Considering vessel segmentation as an iterative tracking process, we propose a new Bayesian tracking algorithm based on particle filters for the delineation of coronary arteries from 3D computed tomography angiograms. It relies on a medial-based geometric model, learned by kernel density estimation, and on a simple, fast and discriminative flux-based image feature. Combining a new sampling scheme and a mean-shift clustering for bifurcation detection and result extraction leads to an efficient and robust method. Results on a database of 61 volumes demonstrate the effectiveness of the proposed approach, with an overall Dice coefficient of 86.2% (and 92.5% on clinically relevant vessels), and a good accuracy of centerline position and radius estimation (errors below the image resolution).

Vital Importance of Delineation of Coronary Artery Anatomy in Atypical Congenital Giant Right Atrial Aneurysm

Introduction: Giant congenital right atrial aneurysm is a very rare congenital heart lesion, which may be asymptomatic or present a variety of symptoms, particularly supraventricular arrhythmias and intracardiac thrombosis formation. Case Presentation: This is a report on a 3.5-month-old male infant with imperforated anus and an unusual-shaped congenital giant right atrial aneurysm with retro-ventricular extension. This unusual shape prevented appearance of cardiomegaly on the chest X-Ray. Surgical resection of the aneurysm was attempted. However, posterior descending coronary artery, which was embedded in the wall of the aneurysm, was irreversibly damaged during the operation. The patient died in the operation room. We concluded that pre-operative delineation of coronary arteries in cases with congenital giant right atrial aneurysm (CGRAA) with extension to the posterior left ventricle is mandatory. Despite the current data that surgical excision of the aneurysm is the treatment of choice, our case required simple closure of the aneurysmal neck from inside the right atrium to be an easier and safer surgical approach for treatment of CGRAA with a tricky anatomy. Conclusions: This case indicates that delineation of coronary artery anatomy in atypical congenital giant right atrial aneurysm is of vital importance. Closure of the aneurysmal sac, instead of aneurysmal resection, is a safer and more simple approach in atypical cases.

Contrast-kinetics-resolved whole-heart coronary MRA using 3DPR

Slow contrast infusion was recently proposed for contrast-enhanced whole-heart coronary MR angiography. Current protocols use Cartesian k-space sampling with empiric acquisition delays, potentially resulting in suboptimal coronary artery delineation and image artifacts if there is a timing error. This study aimed to investigate the feasibility of using time-resolved three-dimensional projection reconstruction for whole-heart coronary MR angiography. With this method, data acquisition was started simultaneously with contrast injection. Sequential time frames were reconstructed by employing a sliding window scheme with temporal tornado filtering. Additionally, a self-timing method was developed to monitor contrast enhancement during a scan and automatically determine the peak enhancement time around which optimal temporal frames were reconstructed. Our preliminary results on six healthy volunteers showed that by using time-resolved three-dimensional projection reconstruction, the contrast kinetics of the coronary artery system throughout a scan could be retrospectively resolved and assessed. In addition, the blood signal dynamics predicted using self-timing was closely correlated to the true dynamics in time-resolved reconstruction. This approach is useful for optimizing delineation of each coronary artery and minimizing image artifacts for contrast-enhanced whole-heart MRA.

Coronary MRA at 3 T using 3d multi-interleaved multi-echo acquisition with varpro fat-water separation

Introduction Coronary MR Angiography is a valuable tool for non-invasive assessment of coronary arteries. Presently, contrastenhanced, fat-saturated, ECG-triggered and navigatorgated 3D spoiled gradient-echo sequence is employed for whole-heart Coronary MRA at 3 T[1]. However, large static field variations at 3 T frequently result in non-uniform fat-suppression over the field-of-view (FOV), obscuring the delineation of coronary arteries. Multi-echo Dixon approaches utilizing iterative decomposition have been shown to provide robust fat-water separation even in the presence of large field inhomogeneities. In this study, an ECG-triggered navigator-gated 3D spoiled gradientecho multi-interleaved multi-echo (GRE-MEMI) pulse sequence is introduced which utilizes VARPRO[2] fatwater separation to achieve reliable fat-suppression and provides enhanced visualization of coronary arteries.

Respiratory self‐gated four‐dimensional coronary MR angiography: A feasibility study

The four-dimensional (4D) coronary MR angiography (MRA) approach has been developed to eliminate the need for accurate determination of the acquisition window and trigger delay time. Diaphragm navigator (NAV) has been the conventional respiratory gating method for free-breathing coronary MRA. However, NAV echo acquisition interrupts the continuous radiofrequency pulse application required for 4D steady-state free precession coronary MRA. The objective of this work was to investigate the feasibility of a respiratory self-gating (RSG) technique for 4D coronary MRA and its effectiveness by comparing with retrospective NAV gating. Data were acquired continuously throughout the cardiac cycle and retrospectively remapped to cardiac phases based on the electrocardiogram signal simultaneously recorded. An RSG signal extracted from a direct measurement of the heart position was used for retrospective respiratory gating and motion correction. In seven healthy volunteers, 4D MRA images were reconstructed, allowing retrospective assessment of the cardiac motion of the coronary artery and selection of the images with the best vessel delineation. Statistical analysis shows that 4D RSG provides coronary artery delineation comparable to mid-diastole images acquired using NAV. Respiratory self-gating is an effective method for eliminating respiratory motion artifacts and allows 4D coronary MRA during free breathing.

Unique application of multislice computed tomography in adults with congenital heart disease

Purpose Adults with congenital heart disease (CHD) form a growing population of patients requiring coronary artery assessment. In light of their increased incidence of coronary anomalies and need for reoperations, it is important to define their coronary anatomy. The purpose of this study was to define the spectrum of coronary artery anatomies and feasibility of coronary artery delineation in adults with CHD using 16- and 64-slice computed tomography angiography. Materials and methods Coronary multislice computed tomography (MSCT) examinations performed in adults with CHD between 2004 and 2005 were reviewed with institutional review board approval. Informed consent was not required. In addition to image quality, the following coronary parameters were evaluated by analysis of axial, multiplanar reformatted, and volume-rendered images: (1) relationship to great arteries, (2) ostia number and location, (3) proximal course, (4) length of vessel seen, and (5) dominance. Results Eighty-five examinations in adults with CHD adults were identified. The relationship of the great vessels, number and location of the coronary ostia, and proximal course of the coronaries could be identified in all studies. Coronary anomalies were detected in 16 (19%) subjects. The entire coronary tree was visible in 77 (91%) of subjects. Conclusions MSCT provides detailed, noninvasive assessment of complex coronary artery anatomy in adults with CHD. MSCT should be considered a useful modality in the assessment of these patients, as it does not require arterial access and provides detailed 3-dimensional anatomic information that has important implications for long-term management.

Coronary MRA with 3D undersampled projection reconstruction TrueFISP.

Undersampled projection reconstruction (PR) offers improved imaging efficiency allowing a relative tradeoff between signal-to-noise ratio (SNR) or streak artifact and the number of acquired k-space views rather than the tradeoff between resolution or aliasing artifact and the number of acquired k-space lines inherent to Fourier imaging techniques. TrueFISP (true fast imaging with steady state precession) is ideally suited for undersampled PR imaging because of its inherently high SNR. The purpose of this work was to investigate the feasibility of using undersampled three-dimensional (3D) PR TrueFISP for breathhold coronary artery imaging. Phantom studies and a preliminary in vivo comparison demonstrated the improved spatial resolution of PR over Fourier TrueFISP with the same imaging time. In a 24-heartbeat coronary imaging scheme, segmented 3D PR TrueFISP provided a 1.0 x 1.0 mm(2) isotropic in-plane voxel size while acquiring between 93 and 153 views per partition. Streak artifacts were present in some images but were not found to impede coronary artery delineation. In conclusion, 3D undersampled PR TrueFISP provides isotropic in-plane voxel size within a single breathhold and is a promising technique for coronary artery imaging.

Three-dimensional true-FISP imaging of the coronary arteries: improved contrast with T2-preparation.

To evaluate the effectiveness of a T2-magnetization preparation scheme for improving coronary artery imaging with true fast imaging with steady-state precession (True-FISP). Simulations were performed to compare the blood-myocardium signal difference with no T2-preparation to that with various T2-preparation times (24, 40, and 60 msec) using an electrocardiogram (ECG)-triggered, segmented True-FISP acquisition. Seven volunteers were imaged to evaluate the effectiveness of T2-preparation for coronary artery delineation using True- FISP and to optimize the T2-preparation time. Simulations showed that T2-preparation improved the signal difference between blood and myocardium over that without T2-preparation. The optimal T2- preparation time was determined to be 40 msec. In volunteer studies, a T2- preparation time of 40 msec provided a significant improvement in contrast- to-noise ratio (CNR) between the coronary arteries and myocardium over that without T2-preparation. It also showed a significant improvement in visualizing the distal portions of the coronary arteries. T2-preparation improves coronary artery delineation with True-FISP.

Coronary artery imaging using contrast-enhanced 3D segmented EPI.

The purpose of the work was to evaluate the effectiveness of extracellular contrast media in improving MR coronary angiography using breath-hold segmented echo-planar imaging (SEPI). Two protocols were designed to optimize the inversion recovery-prepared contrast-enhanced SEPI method. In 15 healthy volunteers, significant improvements in signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), vessel sharpness, and length of visualization were observed post-contrast. The method with two targeted scans to cover the left and right arteries, respectively, following separate 20-mL contrast injections, was found to yield thinner slices and longer right coronary artery (RCA) visualization than a single scan following a 40-mL contrast injection without compromising SNR and CNR. In conclusion, extracellular contrast media substantially improves the delineation of coronary arteries with SEPI. J. Magn. Reson. Imaging 2001;13:676-681.

Three-dimensional MRI of coronary arteries using an intravascular contrast agent.

To assess the effectiveness of an intravascular contrast agent, MS-325, for enhancing the vascular signal in coronary MR angiograms, six minipigs were studied using a three-dimensional, gradient-echo sequence with retrospective respiratory gating. To suppress the myocardial signal, preparatory RF pulses were applied before data acquisition. With the administration of MS-325, the blood signal-to-noise ratio increased by 97-276%, depending on the region of interest in which the blood signal was measured and the precontrast imaging sequence structures. The blood/myocardium contrast-to-noise ratio also significantly increased. High-resolution images (0.58 x 0.58 x 1 mm3) obtained from postmortem pig hearts demonstrated the potential delineation of coronary arteries with MS-325. In conclusion, this study supports further evaluation of the utility of MS-325 in improving coronary MR angiography in humans.

Coronary arteries: three-dimensional MR imaging with retrospective respiratory gating.

Thin-section, three-dimensional (3D) gradient-echo magnetic resonance imaging of the coronary arteries was performed without and with retrospective respiratory gating in 12 healthy volunteers and one patient. In all examinations, results were improved with gating. In five of seven volunteer examinations, coronary artery delineation on images reconstructed by using the least-squares method for motion detection with navigator echoes was found to be equal to that obtained by using edge detection. Images in five other volunteers covered the entire heart with multiple overlapping 3D slabs. The arteries were segmented from the background and could be viewed from any orientation. The lengths of contiguously visible vessels were as follows: left main coronary artery, 11.5 mm +/- 0.4 (mean +/- standard deviation); left anterior descending branch, 115.9 mm +/- 19.7; left circumflex branch, 97.2 mm +/- 12.5; and right coronary artery, 125.9 mm +/- 18.8. This respiratory gating technique clearly improved depiction of the coronary arteries.