Coronary Artery Segments Research Articles

Diagnostic accuracy of carotid intima media thickness in predicting coronary plaque burden on coronary computed tomography angiography in patients with obstructive sleep apnoea

AimTo assess the diagnostic accuracy of common carotid artery intima media thickness (CIMT) for coronary artery disease (CAD) detection in patients with obstructive sleep apnoea (OSA). Materials & methodsPatients with clinically suspected OSA prospectively underwent polysomnography (PSG), ultrasound CIMT measurement and coronary computed tomography angiography (CTA). An average CIMT of ≥0.9 mm in either common carotid artery designated as a positive test. Coronary CTA was the reference standard for the presence of CAD. Coronary plaque presence, volume, density and type were correlated with CIMT findings. Results35 consecutive male patients were enrolled from sleep clinic. Two patients had no evidence of OSA on PSG (apnoea-hypopnea index [AHI]<5/hr), and were excluded. Of the remaining 33, 18 (54%) had mild-moderate OSA (AHI 5–30/hr) and 15 (46%) had severe OSA (AHI >30/hr). Eight (24%) patients had CAD on coronary CTA. Coronary plaques were predominantly non- or partly calcified, and located in proximal coronary artery segments. Sensitivity, specificity, positive and negative predictive and likelihood ratios for a positive CIMT (≥0.9 mm) in diagnosing CAD were 0.5 (95% confidence interval: 0.76–0.12), 0.96 (1–0.89), 80, 85.7, 12.5 and 0.52 respectively. The adjusted odds ratio was 40.8. ConclusionIn patients with OSA, CIMT is a highly specific but poorly sensitive test for detecting CAD.

Feasibility study of coronary CT angiography in single cardiac cycle in patients with high heart rate using 256-row detector CT

Objective To investigate the feasibility of coronary CT angiography in single cardiac cycle and to analyze the image quality and radiation dose in patients with high heart rate(HR) using 256-row detector CT. Methods Ninety-two consecutive patients between October and November 2015 who were suspected coronary artery disease underwent coronary CT angiography (CCTA) were enrolled, which was performed with a 256-row detector CT (Revolution CT, GE Healthcare) using prospective ECG-triggered volume CCTA within a single cardiac cycle with snapshot freeze (SSF) technique. The patients were grouped by HR during CT scans: group A (80—89 bpm, n=56), group B (90—99 bpm, n=20), and group C (≥100 bpm, n=16). Image quality was compared before and after using SSF technique reconstructions in seventy-four patients. The image quality of coronary artery was evaluated blindly by 2 experienced radiologists using a four-point scale based on the 18-segment model according to the Society of Cardiovascular Computed Tomography guidelines. The differences in age, body mass index, heart rate and CT dose index volume, effective dose(ED) among the three groups were compared by using ANOVA analysis or Kruskal-Wallis test, the image quality and interpretability using χ2 test. Comparisons of image quality between standard and SSF were performed with paired Wilcoxon rank sum test. Kappa coefficient was used to test inter-observer agreement. Results A total of 1 065 coronary artery segments, 98.97% (1 054/1 065) met the requirements for diagnosis. No significant difference was found (χ2=1.274, P=0.563) for the diagnostic image quality of coronary artery segments among the 3 groups with 98.64% (651/660), 99.57%(232/233), 99.42% (171/172), respectively. Significant difference (χ2=68.811, P 0.05). Conclusions Single cardiac cycle scan is feasibility for coronary CT angiography in patients with high heart rate using 256-row detector CT. This scan mode can maintain the diagnostic image quality with low radiation dose. SSF technique can improve the image quality. Key words: Heart rate; Coronary vessel; Tomography, X-ray computed; Radiation dosage

Influence of Cardiovascular Risk Factors on the Prevalence of Coronary Atherosclerosis in Patients with Angiographically Normal Coronary Arteries

Cardiovascular (CV) disease is predominately influenced by CV risk factors and coronary computed tomography angiography (CTA) is capable of detecting early-stage coronary artery disease. We sought to determine the influence of CV risk factors on the prevalence of nonobstructive atherosclerosis in patients with normal-appearing coronary arteries in invasive coronary angiography (ICA). In this retrospective analysis, we included 60 consecutive symptomatic patients, having undergone ICA and coronary CTA. Coronary dual source CTA was performed using electrocardiogram-triggered retrospective gated image acquisition at 40%-70% of RR interval (tube voltage 100-120 kV, tube current time product 320-440 mAs, 60 mL contrast, and flow rate 6 mL/s). Out of 60 patients (32 men, mean age 61 ± 11 years) with a normal coronary artery appearance in ICA, 45 (75%) patients showed atherosclerotic plaque in CTA. Plaque was present in 14 of 60 (23%) left main, 41 of 60 (68%) left anterior descending, 21 of 60 (35%) circumflex coronary arteries, and 24 of 60 (40%) right coronary arteries. More than 15% of all coronary artery segments showed detectable plaques. Interobserver agreement ranged from good to very good on a per-patient, per-vessel, and per-segment level. Patients with presence of plaque were significantly older (P = 0.005) and showed higher incidence of arterial hypertension (P = 0.019) as compared to individuals without coronary plaque in dual source computed tomography. The prevalence of coronary atherosclerosis by CTA is substantial in symptomatic patients with normal invasive coronary angiogram. Hypertension and older age significantly influence the prevalence of atherosclerotic plaque and highlight the importance of risk-modifying therapy.

Quantitative angiographic characterisation of coronary artery disease in patients with human immunodeficiency virus (HIV) infection undergoing percutaneous coronary intervention.

Patients with human immunodeficiency virus (HIV) infection have an increased risk of acute myocardial infarction (MI), and 6.5-15% of mortality in this population is attributable to cardiovascular disease. However, the angiographic pattern of coronary artery disease (CAD) in patients with HIV undergoing percutaneous coronary intervention (PCI) remains unknown. We sought to assess and describe the angiographic features and burden of CAD in patients with HIV as compared to those without HIV infection. This is a retrospective, single-centre study comparing 93 patients with HIV infection who underwent PCI between 2003 and 2011 with 93 control patients without HIV infection matched for age (±3 years), gender, diabetes, and year of PCI (±2 years). Quantitative coronary angiography (QCA) was performed for all treated lesions at baseline and following PCI in both groups. One-year clinical outcomes post PCI were also analysed and compared. The mean age for both study populations was 57 years; patients with HIV were more likely to present with ST-segment elevation myocardial infarction (STEMI). Patients had a similar extent of CAD as measured by the presence of multivessel disease as well as SYNTAX score; however, patients with HIV were more likely to have lesions in the proximal segment of the respective coronary artery. While both groups mostly displayed none/mild calcified lesions, HIV+ patients had longer and fewer stenotic lesions. Clinical outcomes at one year were similar. While HIV+ patients were more likely to present with STEMI, detailed coronary angiographic analysis revealed less complex lesions and favourable anatomy. This paradox may suggest alterations in genesis and progression of atherosclerosis in this clinical setting.

Coronary artery dimensions in normal Indians

BackgroundDiameter of coronary artery is an important predictor of outcome after percutaneous coronary interventions and coronary artery bypass graft surgery. There is very limited data available about coronary artery dimensions in an Indian population. AimsTo study the normal dimensions of the coronary artery segments in Indians without coronary artery disease by using quantitative coronary angiography and also to compare the dimensions in Indians with Western. Material and method229 patients who have undergone coronary angiography with entirely normal coronary angiogram were included in our study. ResultsThis study showed the diameter of vessels in males and females when taken together the left main was larger in size followed by proximal LAD, proximal RCA & proximal LCX respectively (4.08±0.44mm, 3.27±0.23mm, 3.20±0.37mm, 2.97±0.37mm).When the vessel diameter was indexed to body surface area there was no statistical difference between male and female (p value>0.05). The computed value of proximal coronary artery diameter unadjusted for individual body surface area, when compared to Caucasians showed that Caucasians have larger coronary artery dimensions than Indians. But when the proximal vessel diameter was indexed to body surface area there was no statistical significant difference between Indians and Caucasians (p value>0.05). ConclusionsWe found that coronary artery size when indexed to body surface area is not statistically different in Indian males and females and compared to Caucasians. However with a smaller body habitus Indians have smaller coronary arteries.

CORONARY ARTERY DISEASE (CAD);

Background: Coronary artery lesion severity is physiological assessed byfractional myocardial flow reserve (FFR). Angiographic assessment of intermediate severitylesions is problematic as inter-observer variability is significant. Hence one is not sure aboutthe hemodynamic or functional significance of these lesions. FFR is helpful in this situationby assessing functional or hemodynamic significance of these intermediate coronary lesions.An FFR value &lt;0.80 identifies ischemia-causing coronary stenosis with an accuracy of &gt;90%suggesting that intermediate coronary lesion is in fact functionally important. Objective: Todetermine the correlation between mean lesion length of diffuse intermediate stenosis (40%-70% stenosis) of proximal and mid segment of major coronary arteries and mean fractional flowreserve (FFR). Study duration: From 1-07-2015 to 31-12-2015. Study design: Cross sectionalstudy. Methodology: After approval from hospital Ethical committee and Informed consent, 60patients with intermediate diffuse lesions on coronary angiography from Faisalabad Institute ofCardiology were enrolled. FFR assessment of diffuse intermediate lesion was done by author.FFR assessment was done using FFR wire during maximal blood flow (hyperemia) whichwas induced by injecting bolus dose of intracoronary adenosine. The cost of procedure wasmanaged by hospital. Results: In this study, 28.33% (n=17) were between 20-50 years of age,mean+SD was calculated as 55.17+8.04 years, 51.67% (n=31) were male and 48.33% (n=29)were females. Correlation between mean lesion length of diffuse intermediate stenosis (40%-70% stenosis) of proximal and mid segment of major coronary arteries and mean fractionalflow reserve (FFR) was recorded it shows that mean lesion length was 24.53+4.78 mm whileFFR was recorded as 0.72+0.12, the value of R is -0.1928, technically a negative correlation,the relationship between variables is only weak (the nearer the value is to zero, the weakerthe relationship). The value of R2, the coefficient of determination, is 0.0372. Conclusion: Thecorrelation between mean lesion length of diffuse intermediate stenosis (40%-70% stenosis) ofproximal and mid segment of major coronary arteries and mean fractional flow reserve (FFR)was weak and did not suggest any hemodynamic significance of diffuse intermediate coronaryartery lesions.

Mobile thrombus extending from the distal segment of the left main coronary artery to the left anterior descending artery

Left main coronary artery disease was originally described by James Bryan Herrick, who also described the symptoms of myocardial infarction. Acute coronary syndromes characterized by thrombus formation in the left main coronary artery represent an uncommon form of atherosclerotic cardiac diseases. We describe a 77-year old female patient who had mobile thrombus extending from the distal segment of the left main coronary artery to the left anterior descending artery.

Specific Characteristics of Coronary Atherosclerosis

In this review, we present modern aspects of etiology and pathogenesis of atherosclerosis. We describe the roles played by inflammatory cells, components of cellular response in allergic reactions, disturbances of carbohydrate metabolism, cellular aging, and infection at various stages of formation of atherosclerotic plaques. Special attention is given to the specific characteristics of atherosclerosis and calcification of coronary arteries. We show the influence of age and gender on the disease progression. The review includes information on the importance of myocardial bridges for the change of hemodynamics in segments of coronary arteries. The data presented indicate that differences in localization of atherosclerotic lesions between systems of the right and left coronary arteries depends on their hemodynamic, anatomical and physiological characteristics. According to the literature, anterior descending artery is more vulnerable in this respect.

Managing practical issues with percutaneous treatment of spontaneous coronary artery dissection in the cardiac catheterization laboratory: An interesting case report

Spontaneous coronary artery dissection (SCAD) is a rare condition and uncommon cause of acute coronary syndrome which is associated with high acute phase mortality with an estimated prevalence of approximately 0.7%. SCAD is known to occur more commonly in young women during pregnancy or postpartum period, and in most cases, it involves a single coronary artery. It has also been reported in patients with atherosclerosis. SCAD is generally treated by percutaneous intervention and stenting. While stenting a segment of the right coronary artery (RCA) with dissection, opening the balloon in the false lumen or placing a stent in the false plane can lead to abrupt closure of the RCA leading to on table catastrophe, thereby confirming that we are in the true lumen is of pivotal importance. Simple maneuvers to prevent this error can be lifesaving. In this article, we have presented a few practical measures to deal with this dilemma in the background of a patient who was found to have spontaneous spiral dissection of the RCA while being evaluated for angina.

Increased risk of coronary perforation during percutaneous intervention of myocardial bridge: What histopathology says.

Introduction: Myocardial bridge (MB) is a segment of a major epicardial coronary artery that goes intramurally under a bridge of overlying myocardium. Complications have been reported during or after stent implantation particularly coronary perforation. The aim of this study was to determine histological differences between proximal left anterior descending artery (LAD) and the tunneled segment that may have a possible role in increased risk of coronary artery perforation during percutaneous coronary intervention. Methods: Twenty specimens of MB were obtained from dissection of 45 cadavers. Sections were stained using hematoxylin and eosin (H&E), and trichrome methods. The proximal section and the tunneled artery were compared with a normal sample in terms of the characteristics of a muscle artery. Results: The findings of this study showed an MB prevalence of 51%, as 23 out of the 45 examined cadavers were discovered to be afflicted by the MB. The intima layer in the suffering artery had gone through significant hypertrophy, while it had remained thin in the tunneled artery section. The epithelial cells under the bridge were spindle-shaped, while they were polygonal in the proximal section. In the myocardium the nuclei of the muscle fibers in the MB section were smaller than the normal section. Adventitial layer was almost normal. Conclusion: The histopathological differences between MB and proximal part of vessel combined with small vessel diameter in the tunneled segment can explain the high incidence of the LAD rupture and perforation in the section under the bridge.

High-Pitch Coronary CT Angiography at 70 kVp Adopting a Protocol of Low Injection Speed and Low Volume of Contrast Medium.

ObjectiveTo evaluate the feasibility and image quality (IQ) of prospectively high-pitch coronary CT angiography (CCTA) with low contrast medium injection rate at 70 kVp.Materials and MethodsOne hundred and four patients with suspected coronary artery disease (body mass index < 26 kg/m2, sinus rhythm and heart rate < 70 beats/min) were prospectively enrolled and randomly divided into two groups. In group A and group B, 28 mL and 40 mL of 370 mgI/mL iodinated contrast media was administrated at a flow rate of 3.5 and 5 mL/s, respectively. CT values, noise, signal-to-noise ratio, contrast-to-noise ratio (CNR) of the proximal segments of coronary arteries and subjective IQ were evaluated.ResultsThe CT values and noise in group A were significantly lower than those in group B (434–485 Hounsfield units [HU] vs. 772–851 HU, all p < 0.001; 17.8–22.3 vs. 23.3–26.4, all p < 0.005). The CNRs of the right coronary artery and left main artery showed no statistical difference between the two groups (42.1 ± 13.8 vs. 36.8 ± 16.0, p = 0.074; 38.7 ± 10.6 vs. 38.1 ± 17.0, p = 0.819). No statistical difference was observed between the two groups in IQ scores (3.04 ± 0.75 vs. 3.0 ± 0.79, p = 0.526) and diagnostic ratio (96.1% [50/52] vs. 94.2% [49/52], p = 0.647).ConclusionProspective high-pitch CCTA at 70 kVp with 28 mL of contrast media and injection rate of 3.5 mL/s could provide diagnostic IQ for normal-weight patients with heart rate of < 70 beats/min.

Use of orbital atherectomy in acute myocardial infarction via the transradial approach.

Severe coronary artery calcifications pose an ongoing challenge when performing percutaneous coronary interventions, resulting in an increased likelihood of procedural complications. Orbital atherectomy (OA) has emerged as a promising technology that helps improve outcomes in this complex patient population. Its safety and efficacy are yet to be demonstrated in the setting of acute myocardial infarction. We present a case of a patient with acute ST-elevation myocardial infarction (STEMI) evaluated with emergent transradial coronary angiography. The culprit lesion was a severely stenotic, heavily calcified, segment of the right coronary artery. The use of OA facilitated lesion expansion and implantation of a drug-eluting stent. Although OA should be considered as contraindicated for the management of soft-ruptured plaque, which accounts for the majority of STEMI presentations, it may be well applied to the small subset of patients with calcified nodule pathology, even in the acute setting.

Stenting of Spontaneous Coronary Artery Dissection From a Pathological Point of View.

A 32-year-old female recently postpartum was admitted with chest pain and shortness of breath. She was diagnosed with acute inferior myocardial infarction and taken to catheterization laboratory in cardiogenic shock. The proximal right coronary artery was occluded, and an everolimus-eluting stent (Abbott Vascular, Santa Clara, CA) was implanted successfully. Left coronary angiography showed 50% stenosis of proximal left anterior descending (LAD) and total occlusion of left circumflex. The patient remained in cardiogenic shock despite insertion of an intra-aortic balloon pump and temporary pacemaker and died after cardiac arrest. At autopsy (Figure [A]), coronary arteries showed no gross atherosclerosis, but diffuse coronary artery dissections, involving left main, LAD, left circumflex, and right coronary artery. The stent was implanted in the true lumen (TL, Figure [A3 through A5]), though it was not well expanded and the underlying dissection was still observed. The dissection in the right coronary artery extended both proximally and distally, but severe narrowing was only observed in the distal right …

Abstract 12919: Co-aligned and Inherently Co-registered Intravascular Ultrasound and Optical Coherence Tomography in a Hybrid Imaging Catheter is Feasible for Characterizing Coronary Artery Disease

Introduction: Combined use of intravascular ultrasound (IVUS) and optical coherence tomography (OCT) demonstrates synergistic benefits, which may improve the characterization and therapeutics of coronary artery disease. However, sequential use of stand-alone catheters is impractical. Hypothesis: IVUS and OCT can be implemented in a dual-modality catheter with co-alignment of imaging beams, allowing simultaneous imaging of coronary lesions that are inherently co-registered. Methods: A 3-French rotational custom hybrid IVUS-OCT imaging catheter was built using a 40 MHz ultrasound transducer with embedded OCT imaging fiber optics, as well as co-alignment of the IVUS and OCT imaging centers. Ex-vivo intraluminal IVUS and OCT images of 70 coronary artery segments from 5 cadaveric autopsies were acquired simultaneously at 25 frames/sec with 5 mm/sec pull back. Imaging at 100 frames/sec was also briefly conducted. Thirty segments had potential pathological findings and underwent histologic slicing and hematoxylin-eosin staining at 250μm intervals. Morphological features were identified based on standard criteria for IVUS and OCT, then compared to corresponding histology findings. Results: IVUS and OCT were well co-registered based on fiduciary markings. A number of vascular pathologies were identified, including normal, fibrous, lipid-rich, calcified, and thrombus tissues. These findings were confirmed on corresponding histology. Complementary features of IVUS and OCT were also qualitatively apparent. IVUS showed deeper image depth to allow assessment of plaque size and vascular remodeling. OCT showed superior near field imaging, resolution and tissue contrast. Conclusions: We demonstrated feasibility of co-aligning IVUS and OCT, providing co-registered hybrid images that highlight the complementary advantages of both modalities. Quantitative comparison and validation of this technology is on-going.

Endothelial lipase plasma levels are increased in both sexes in stable coronary artery disease and only in women with acute coronary syndrome but not associated with the severity of coronary artery disease.

To investigate whether endothelial lipase (EL) plasma levels are increased in stable coronary artery disease (sCAD) and acute coronary syndrome (ACS) patients, as well as to test the association of EL plasma levels and the severity of CAD and sex. The study was performed as a single-center, cross-sectional, observational research on 72 sCAD and 187 ACS patients in the Sisters of Charity University Hospital Centre, Zagreb, Croatia, between December 1, 2011 and December 1, 2012. EL plasma levels were measured using ELISA. EL plasma levels were significantly higher in sCAD patients (median 311.3 pg/mL, interquartile range [IQR] 250.4-422.6 pg/mL) than in ACS patients (median=258.7 pg/mL, IQR=162.1-356.0 pg/mL; P<0.001). EL levels in female ACS patients were significantly higher (median 314.5 pg/mL, IQR 218.3-420.8 pg/mL) than in male ACS patients (median 225.4 pg/mL, IQR 148.7320.1 pg/mL; P<0.001) and similar to the EL levels in the sCAD patients. There was no significant correlation between EL plasma levels and the GENSINI score and between EL plasma levels and the number of atherosclerotic coronary artery segments in either the ACS (rho=-0.09, P=0.247; rho=0.12, P=0.106, respectively) or sCAD group (rho=0.04, P=0.771; rho=0.06, P=0.643, respectively). Our results suggest that EL plasma levels discriminate male but not female patients with different clinical presentations of CAD, as well as female and male ACS patients. EL plasma levels are not significantly correlated with CAD severity.

The relationship between myocardial bridge in mural coronary artery segment and coronary atherosclerosis

Objective: The myocardial bridging (MB) prevalence, anatomic characteristics of MB, and the relationship between characteristics of MB in mural coronary artery segment and coronary atherosclerosis were analyzed. Methods: In this perspective nonrandomized controlled study, a total of 1 132 patients who admitted to our hospital for suspected or known coronary artery disease from January 2012 to June 2013 were enrolled. All patients underwent dual-source 64-slice spiral CT coronary angiography. The general patient characteristics including gender, age, history of hypertension, diabetes, hyperlipidemia and smoking, serum level of total cholesterol (TC) and LDL-C were recorded. The length, depth and the degree of compression of myocardial bridge in systolic or diastolic phase were also analyzed in patients with MB. The relationship between MB and coronary atherosclerosis, the characteristics of MB and coronary atherosclerosis were analyzed by Spearman correlation analysis, univariate logistic regression analysis, variate logistic regression analysis and linear regression analysis. Results: Myocardial bridging was detected in 330 out of 1 132 patients, and MB was mostly located in the mural coronary artery (329/330) and at the mid-distal segment of the left anterior descending artery (LAD). Average MB length was 20.1 mm (3.3-95.5 mm) and the average depth was 2.13 mm (0.24-12.40 mm). There were 140 patients with intramyocardial MB (42.6%) and 189 patients with superficial MB (57.4%). Myocardial bridging was an independent protective factor of coronary atherosclerosis (OR=0.361, P=0.000) and the proximal segment of MB was more susceptible to atherosclerosis compared to the distal segment of MB (P=0.000). Multivariate analysis revealed that age, hypertension and the degree of compression of myocardial bridge in diastolic phase were independent factors related to the atherosclerosis (odds ratio: 1.064, 2.186 and 1.049 respectively, P value: 0.000, 0.002 and 0.000). The depth of MB was significantly correlated with systolic or diastolic narrowing(OR: 4.227, 3.398 and P value: 0.000, 0.001). Conclusions: The prevalence of myocardial bridging is 29% in this patient cohort. The proximal segment of myocardial bridging in mural coronary artery is more susceptible to atherosclerosis. In addition, the depth of myocardial bridging and the degree of compression of myocardial bridge in diastolic phase are the independent factors related to atherosclerosis.

Prediction of Atherosclerotic Plaque Development in an In Vivo Coronary Arterial Segment Based on a Multilevel Modeling Approach.

The aim of this study is to explore major mechanisms of atherosclerotic plaque growth, presenting a proof-of-concept numerical model. To this aim, a human reconstructed left circumflex coronary artery is utilized for a multilevel modeling approach. More specifically, the first level consists of the modeling of blood flow and endothelial shear stress (ESS) computation. The second level includes the modeling of low-density lipoprotein (LDL) and high-density lipoprotein and monocytes transport through the endothelial membrane to vessel wall. The third level comprises of the modeling of LDL oxidation, macrophages differentiation, and foam cells formation. All modeling levels integrate experimental findings to describe the major mechanisms that occur in the arterial physiology. In order to validate the proposed approach, we utilize a patient specific scenario by comparing the baseline computational results with the changes in arterial wall thickness, lumen diameter, and plaque components using follow-up data. The results of this model show that ESS and LDL concentration have a good correlation with the changes in plaque area [R2 = 0.365 (P = 0.029, adjusted R2 = 0.307) and R2 = 0.368 (P = 0.015, adjusted R2 = 0.342), respectively], whereas the introduction of the variables of oxidized LDL, macrophages, and foam cells as independent predictors improves the accuracy in predicting regions potential for atherosclerotic plaque development [R2 = 0.847 (P = 0.009, adjusted R2 = 0.738)]. Advanced computational models can be used to increase the accuracy to predict regions which are prone to plaque development. Atherosclerosis is one of leading causes of death worldwide. For this purpose computational models have to be implemented to predict disease progression.

Examining a hypothetical quantitative model for better approximation of culprit coronary artery and site of stenosis on 99mTc-sestamibi gated myocardial perfusion SPECT.

A hypothetical quantitative model of analyzing gated myocardial perfusion SPECT is proposed and examined for the feasibility of its use as a predictor of diseased coronary artery and approximating the site of stenosis to determine whether it could serve as a useful noninvasive complement for coronary angiography. The extent and severity of perfusion defects on rest gated myocardial perfusion imaging SPECT-images were assessed on a five-point scale in a standard 17-segment model and total perfusion deficit was quantified by automated software. The first step was to locate the diseased coronary artery using a quantitative method: for this, the score of each segment belonging to a particular coronary artery was determined using a systematic presumptive approach. After determination of specific coronary artery segments, the scores of the contiguous segments in three short axis slices (apical, middle, and basal) were summed for six subdivisions (anterior, anterolateral, inferolateral, inferior, anteroseptal, and inferoseptal). The site of stenosis was determined from (a) the initial approximation of the involved segments with a defect score of 2-4 and (b) subsequent calculation of the defect score of each of the six subdivisions and allocating the site through a preassigned number for each coronary artery. For each coronary artery, only the subdivision with the highest defect score was considered. Proximal, middle, and distal segments of left anterior descending artery (LAD) were considered to be represented when the summed value of a subdivision within a particular arterial territory was more than or equal to 7, between 5 and 7, 5 and 3, respectively. For the left circumflex and right coronary artery, summed scores (of respective subdivisions) of more than or equal to 5 and between 3 and 5 were preassigned to proximal and distal stenosis, respectively. The results were then correlated with the coronary angiographic data. On coronary angiography, proximal LAD occlusion was considered when the site of occlusion occurred proximal to the first diagonal branch and a mid-LAD occlusion from the first diagonal branch to the next diagonal branch. Proximal left circumflex artery occlusion is considered as those located before the first relevant marginal branch and distal left circumflex artery occlusion is beyond the first marginal branch. From the ostium to the origin of the first acute marginal artery was considered the proximal segment of the right coronary artery and thereafter was designated as distal. The result obtained by the quantitative model was compared with the angiographic data along with statistical analysis. The unweighted κ-value was 0.803 and 95% confidence interval was between 0.716 and 0.890. Both the proposed quantitative myocardial perfusion imaging model and the angiographic results were in strong agreement; however, this model needs to be examined in a larger number of patients in a prospective setting to explore its pitfalls and define its practical applicability in future.

Coronary CT angiography in patients with implanted cardiac devices: initial experience with the metal artefact reduction technique.

Single-energy metal artefact reduction (SEMAR), a new technique that can now be used in routine CT examinations, has recently become applicable to volume data acquired with electrocardiography gating. We evaluated the effect of this technique on the visualization of the coronary arteries in patients harboring cardiac devices. We subjected 8 patients (7 males, 1 female; mean age 65.5 ± 11.3 years) with implanted cardiac devices to coronary CT angiography on a 320-slice CT scanner (Aquilion ONE Vision™; Toshiba Medical Systems Corp., Tokyo, Japan). Image data sets were reconstructed with and without SEMAR. Two radiologists visually evaluated the image quality based on metal artefacts from the electronic device leads using a four-point scale (1 = vessel not visible to 4 = minimal or no metal artefacts). Images with a score of 3 or 4 were considered diagnostic. In both SEMAR and non-SEMAR data sets, 94 coronary artery segments were available for evaluation. Without SEMAR, 11 segments (11.7%) were rated as non-diagnostic; SEMAR improved the image quality of 9 of the 11 segments (81.8%), and the images became diagnostic. SEMAR reduced metal artefacts from the electronic device leads and improved the image quality of the coronary arteries in patients with cardiac devices. Advances in knowledge: SEMAR has recently become applicable to volume data acquired with electrocardiography gating. SEMAR reduces metal artefacts elicited by electronic device leads and improves the image quality of the coronary arteries in patients with cardiac devices.

Coronary artery analysis: Computer-assisted selection of best-quality segments in multiple-phase coronary CT angiography.

The authors are developing an automated method to identify the best-quality coronary arterial segment from multiple-phase coronary CT angiography (cCTA) acquisitions, which may be used by either interpreting physicians or computer-aided detection systems to optimally and efficiently utilize the diagnostic information available in multiple-phase cCTA for the detection of coronary artery disease. After initialization with a manually identified seed point, each coronary artery tree is automatically extracted from multiple cCTA phases using our multiscale coronary artery response enhancement and 3D rolling balloon region growing vessel segmentation and tracking method. The coronary artery trees from multiple phases are then aligned by a global registration using an affine transformation with quadratic terms and nonlinear simplex optimization, followed by a local registration using a cubic B-spline method with fast localized optimization. The corresponding coronary arteries among the available phases are identified using a recursive coronary segment matching method. Each of the identified vessel segments is transformed by the curved planar reformation (CPR) method. Four features are extracted from each corresponding segment as quality indicators in the original computed tomography volume and the straightened CPR volume, and each quality indicator is used as a voting classifier for the arterial segment. A weighted voting ensemble (WVE) classifier is designed to combine the votes of the four voting classifiers for each corresponding segment. The segment with the highest WVE vote is then selected as the best-quality segment. In this study, the training and test sets consisted of 6 and 20 cCTA cases, respectively, each with 6 phases, containing a total of 156 cCTA volumes and 312 coronary artery trees. An observer preference study was also conducted with one expert cardiothoracic radiologist and four nonradiologist readers to visually rank vessel segment quality. The performance of our automated method was evaluated by comparing the automatically identified best-quality segments identified by the computer to those selected by the observers. For the 20 test cases, 254 groups of corresponding vessel segments were identified after multiple phase registration and recursive matching. The AI-BQ segments agreed with the radiologist's top 2 ranked segments in 78.3% of the 254 groups (Cohen's kappa 0.60), and with the 4 nonradiologist observers in 76.8%, 84.3%, 83.9%, and 85.8% of the 254 groups. In addition, 89.4% of the AI-BQ segments agreed with at least two observers' top 2 rankings, and 96.5% agreed with at least one observer's top 2 rankings. In comparison, agreement between the four observers' top ranked segment and the radiologist's top 2 ranked segments were 79.9%, 80.7%, 82.3%, and 76.8%, respectively, with kappa values ranging from 0.56 to 0.68. The performance of our automated method for selecting the best-quality coronary segments from a multiple-phase cCTA acquisition was comparable to the selection made by human observers. This study demonstrates the potential usefulness of the automated method in clinical practice, enabling interpreting physicians to fully utilize the best available information in cCTA for diagnosis of coronary disease, without requiring manual search through the multiple phases and minimizing the variability in image phase selection for evaluation of coronary artery segments across the diversity of human readers with variations in expertise.