Comparison of multislice computed tomography with intravascular ultrasound for detection and characterization of coronary artery plaques: a systematic review

Purpose

Multislice computed tomography (MSCT) is a novel non-invasive test for detection and analysis of coronary artery plaques. A systematic review was conducted of the literature to compare MSCT with IVUS as the reference standard for assessing coronary artery plaques.

Materials and methods

We performed a literature search in the online database MEDLINE, which was accessed at http://www.pubmed.gov on 9th April 2008.

Results

The search identified 14 studies with 340 patients (mean age 59 ± 5 years). The systematic review revealed a sensitivity of MSCT on the lesion level (n = 1779 coronary plaques) on the order of 90% (range from 87 to 92%) in comparison to IVUS. Per-segment analysis (n = 356) yielded a lower sensitivity of 81-86%. In the per-vessel analysis (n = 90), MSCT had a better sensitivity and specificity for the RCA (83-89% and 92-100%) and the LAD (83-87% and 93%) than for the LCX (71-85% and 77-89%), and on the vessel level and the cross-section analysis MSCT was more sensitive for calcified plaques than for non-calcified plaque. It is noteworthy that most studies provide only incomplete data on technical and methodological parameters such as radiation exposure and patient characteristics.

Conclusion

MSCT is an accurate and reliable test for detection of coronary artery plaques in comparison to IVUS with limitations in regards to the LCX and non-calcified plaques. Studies published thus far are limited by the sample sizes and methodological quality issues.     

Accuracy of coronary computed tomography angiography vs intravascular ultrasound for evaluation of vessel area

BackgroundWe evaluated the accuracy of commonly used thresholds for vessel area evaluation on coronary CT angiography (CTA) and assessed ability of CTA to image the adventitial border.MethodsWe evaluated 137 paired (coronary CTA and intravascular ultrasound [IVUS]) coronary artery cross-sections in 30 patients. CTA analysis included measurements of external vessel border area defined at Hounsfield unit (HU) thresholds of 0 (presumed adventitia), 50, and 70 (presumed external elastic membrane [EEM]). IVUS analysis included measurements of lumen, EEM, and outer border of the highly echogenic area adjacent to EEM (presumed adventitia area).ResultsHigh correlation was found between CTA and IVUS measurements for EEM areas (R² = 0.65, P < .001 and R² = 0.60, P < .001 for CTA thresholds of 50 and 70 HU, respectively). CTA and IVUS measurements of adventitia areas were significantly correlated (R² = 0.74; P < .001), with no significant difference between the 2 methods (20.2 ± 6.4 mm² vs 19.8 ± 6.4 mm², respectively; P = .278). Cross-sectional coronary lumen radiodensity on CTA images and plaque burden measured on IVUS significantly affected the accuracy of CTA in assessment of the EEM area but not the presumed adventitial area.ConclusionsWe have demonstrated that use of a 50-HU threshold for vessel area determination by CTA led to its significant overestimation, whereas 70-HU threshold was close to that of EEM on IVUS. CTA may accurately delineate the coronary adventitial border by using a 0-HU threshold.     

Quantification of coronary stenosis by dual source computed tomography in patients: a comparative study with intravascular ultrasound and invasive angiography

Objective

To determine the accuracy of dual-source CT (DSCT) to quantify coronary stenosis compared to intravascular ultrasound (IVUS) and quantitative coronary angiography (QCA).

Methods

21 patients (23 vessels) were examined with DSCT, IVUS and invasive coronary angiography. Coronary minimal luminal diameter (MLD) and area (MLA) were measured in cross-sectional multi-planar reformatted images perpendicular to the vessel long-axis. The vessel cross-sectional area stenosis (MLA/CSA ratio) was calculated. DSCT results were compared with IVUS and QCA.

Results

A good correlation between DSCT and IVUS was noted for diameter and area stenosis (r = 0.69 and r = 0.73), with an overestimation of MLD stenosis by DSCT (+9.1%) and an underestimation of MLA stenosis (−5.8%). For MLD and MLA, high correlation coefficients (r = 0.78 and r = 0.90, respectively) were found between DSCT and IVUS; and the bias was almost zero (−0.41 mm and +0.1 mm², respectively).The correlation between DSCT and QCA was moderate (r = 0.60) for MLD stenosis with minor overestimation by DSCT (+4.0%) and moderate (r = 0.59) for MLD (bias, +0.01 mm).The cross-sectional area stenosis showed a moderate correlation (r = 0.59) between DSCT and IVUS (+0.00).

Conclusions

DSCT allows accurate quantification of coronary stenosis as compared to IVUS. An excellent correlation was found for the MLA between DSCT and IVUS.     

Implications of computed tomography reconstruction algorithms on coronary atheroma quantification: Comparison with intravascular ultrasound

BackgroundAdvances in coronary computed tomography angiography (CCTA) reconstruction algorithms are expected to enhance the accuracy of CCTA plaque quantification. We aim to evaluate different CCTA reconstruction approaches in assessing vessel characteristics in coronary atheroma using intravascular ultrasound (IVUS) as the reference standard.MethodsMatched cross-sections (n ?= ?7241) from 50 vessels in 15 participants with chronic coronary syndrome who prospectively underwent CCTA and 3-vessel near-infrared spectroscopy-IVUS were included. Twelve CCTA datasets per patient were reconstructed using two different kernels, two slice thicknesses (0.75 ?mm and 0.50 ?mm) and three different strengths of advanced model-based iterative reconstruction (IR) algorithms. Lumen and vessel wall borders were manually annotated in every IVUS and CCTA cross-section which were co-registered using dedicated software. Image quality was sub-optimal in the reconstructions with a sharper kernel, so these were excluded. Intraclass correlation coefficient (ICC) and repeatability coefficient (RC) were used to compare the estimations of the 6 CT reconstruction approaches with those derived by IVUS.ResultsSegment-level analysis showed good agreement between CCTA and IVUS for assessing atheroma volume with approach 0.50/5 (slice thickness 0.50 ?mm and highest strength 5 ADMIRE IR) being the best (total atheroma volume ICC: 0.91, RC: 0.67, p ?< ?0.001 and percentage atheroma volume ICC: 0.64, RC: 14.06, p ?< ?0.001). At lesion-level, there was no difference between the CCTA reconstructions for detecting plaques (accuracy range: 0.64–0.67; p ?= ?0.23); however, approach 0.50/5 was superior in assessing IVUS-derived lesion characteristics associated with plaque vulnerability (minimum lumen area ICC: 0.64, RC: 1.31, p ?< ?0.001 and plaque burden ICC: 0.45, RC: 32.0, p ?< ?0.001).ConclusionCCTA reconstruction with thinner slice thickness, smooth kernel and highest strength advanced IR enabled more accurate quantification of the lumen and plaque at a segment-, and lesion-level analysis in coronary atheroma when validated against intravascular ultrasound. Clinicaltrials.gov (NCT03556644)     

Endothelial shear stress computed from coronary computed tomography angiography: A direct comparison to intravascular ultrasound

IntroductionIntravascular ultrasound (IVUS) studies have shown that biomechanical variables, particularly endothelial shear stress (ESS), add synergistic prognostic insight when combined with anatomic high-risk plaque features. Non-invasive risk assessment of coronary plaques with coronary computed tomography angiography (CCTA) would be helpful to enable broad population risk-screening.AimTo compare the accuracy of ESS computation of local ESS metrics by CCTA vs IVUS imaging.MethodsWe analyzed 59 patients from a registry of patients who underwent both IVUS and CCTA for suspected CAD. CCTA images were acquired using either a 64- or 256-slice scanner. Lumen, vessel, and plaque areas were segmented from both IVUS and CCTA (59 arteries, 686 3-mm segments). Images were co-registered and used to generate a 3-D arterial reconstruction, and local ESS distribution was assessed by computational fluid dynamics (CFD) and reported in consecutive 3-mm segments.ResultsAnatomical plaque characteristics (vessel, lumen, plaque area and minimal luminal area [MLA] per artery) were correlated when measured with IVUS and CCTA: 12.7 ​± ​4.3 vs 10.7 ​± ​4.5 ​mm², r ​= ​0.63; 6.8 ​± ​2.7 vs 5.6 ​± ​2.7 ​mm², r ​= ​0.43; 5.9 ​± ​2.9 vs 5.1 ​± ​3.2 ​mm², r ​= ​0.52; 4.5 ​± ​1.3 vs 4.1 ​± ​1.5 ​mm², r ​= ​0.67 respectively. ESS metrics of local minimal, maximal, and average ESS were also moderately correlated when measured with IVUS and CCTA (2.0 ​± ​1.4 vs 2.5 ​± ​2.6 ​Pa^, r ​= ​0.28; 3.3 ​± ​1.6 vs 4.2 ​± ​3.6 ​Pa, r ​= ​0.42; 2.6 ​± ​1.5 vs 3.3 ​± ​3.0 ​Pa, r ​= ​0.35, respectively). CCTA-based computation accurately identified the spatial localization of local ESS heterogeneity compared to IVUS, with Bland-Altman analyses indicating that the absolute ESS differences between the two CCTA methods were pathobiologically minor.ConclusionLocal ESS evaluation by CCTA is possible and similar to IVUS; and is useful for identifying local flow patterns that are relevant to plaque development, progression, and destabilization.     

The use of computed tomography in the diagnosis of coronary artery bypass graft patency

In a preliminary evaluation of the use of dynamic computed tomography (CT) for the detection of patent aortocoronary bypass grafts, 30 patients were scanned either during the early postoperative peroid or after graft patency was determined by angiography. To visualize the proximal grafts, CT scans were taken through the aortic root following an intravenous bolus injection of contrast medium. Patent bypass grafts to the left anterior descending and right coronary arteries were demonstrated in 77.5%, while posterior grafts to the circumflex and obtuse marginal coronary arteries were detected in 40%. With its pontential for extracting dynamic events, CT scanning provides a new, noninvasive modality for the diagnosis of patent bypass grafts, which heretofore have only been visualized by selective angiography.     

128层CT冠状动脉成像对左心室功能的评价

目的:应用冠状动脉成像原始数据,了解左心室形态变化,评价整体左心室功能。方法:收集90例患者冠状动脉成像原始数据,行MPR,观察左心室形态和各心肌节段的变化,并应用心功能分析软件自动计算出左心室收缩末期容积(ESV)、舒张末期容积(EDV)和射血分数(EF)。根据冠状动脉、左心室形态及整体左心室功能,将所有患者分为对照组、冠心病组、左心室肥厚组及心功能衰竭组,结合各组左心室形态变化,将左心室ESV、EDV和EF进行统计学比较和分析。结果:对照组患者冠状动脉和左心室形态正常;冠心病组左心室壁局限性增厚7例和变薄13例;左心室肥厚组左心室缩小、心室壁增厚;心功能衰竭组心室扩大、室壁普遍变薄。对照组、冠心病组、左心室肥厚组、心功能衰竭组平均EDV和ESV分别为(133.58±14.91)mL、(51.33±11.06)mL;(130.68±11.53)mL、(56.16±8.24)mL;(97.59±8.18)mL、(29.53±4.78)mL;(229.40±50.64)mL、(171.27±60.64)mL。冠心病组与对照组平均EDV和ESV比较,差异无统计学意义,左心室肥厚组及心功能衰竭组与对照组比较,差异均有统计学意义(P0.001)。对照组、冠心病组、左心室肥厚组、心功能衰竭组EF分别为(61.25±5.83)%、(56.37±6.79)%、(68.94±5.36)%和(26.33±8.30)%,差异均有统计学意义。结论:应用冠状动脉成像原始数据,结合冠状动脉及左心室形态改变,无创评价左心室整体功能,实用而可行,可为临床提供更多有价值的信息。     

Assessment of nonstenotic coronary lesions by 64-slice multidetector computed tomography in comparison to intravascular ultrasound: Evaluation of nonculprit coronary lesions

Background

Multidetector computed tomography (MDCT) has recently emerged as a potential noninvasive alternative for high-resolution imaging of coronary arteries.

Objective

In this study, we evaluated 64-slice MDCT for detection, quantification, and characterization of atherosclerotic plaque burden in nonculprit lesions.

Methods

Data from 11 patients who underwent both MDCT and intravascular ultrasound (IVUS) for suspected coronary artery disease were collected, and a total of 17 coronary segments and 122 cross-sectional slices were analyzed by MDCT and IVUS. Coronary segments on MDCT were coregistered to IVUS, and each obtained slice was scored by 2 blinded observers for presence and type of plaque. Quantitative measurements included cross-sectional vessel area, lumen area, wall area, plaque volume, and plaque burden. Mean and standard deviation of Hounsfield units (HUs) were recorded for plaque when present.

Results

Overall sensitivity for plaque detection was 95.0%, and specificity, positive predictive value, negative predictive value were 88.7%, 89.1%, and 94.8%, respectively. Spearman's correlation coefficients were 0.85, 0.75, 0.70, 0.89, and 0.54 for cross-sectional vessel area, lumen area, wall area, plaque volume, and plaque burden, respectively. The interobserver variability for plaque burden and plaque volume measurements between readers on 64-MDCT was high at 32.7% and 30.4%, respectively. Combined noncalcified plaque had a mean MDCT density significantly different from that of calcified plaque. Soft and fibrous plaques were not able to be distinguished based on their HU values.

Conclusion

Sixty-four-slice MDCT had good correlation with IVUS but with high interobserver variability. Plaque characterization remains a challenge with present MDCT technology.     

Iliofemoral artery lumen volume assessment with three dimensional multi-detector computed tomography and vascular complication risk in transfemoral transcatheter aortic valve replacement

BackgroundTransfemoral Transcatheter Aortic Valve Replacement (TAVR) carries a risk of Vascular Complications (VCs) at the access site. The currently used measures for assessing the risk for VCs are not accurate enough, and sometimes fail to predict them. We therefore aimed to examine whether Iliofemoral artery lumen volume (IFV) assessment with 3-dimensional computed tomography (CT) predicts VCs after transfemoral TAVR.MethodsWe identified 45/560 trans-femoral TAVR patients with VC, then performed nearest neighbor 1:1 matching for patients with no VC, matching for age, sex, TAVR year, valve size and type, closure-device, sheath size and peripheral vascular disease. IFV, minimal diameter, tortuosity, and calcification were measured, and their diagnostic performance assessed.ResultsThe final analysis included 45 patients with and 45 patients without VCs. The two groups were well balanced. For all patients, median IFV was 8.65 ml (IQR 6.5–11.95). IFV was lower in patients with VC compared to patients without VC: 7.10 ml (IQR 5.4–9.0) vs. 10.10 ml (IQR 8.3–13.3), p < 0.001. VC risk had marginal association with iliofemoral artery minimal diameter (p = 0.06) and no association with tortuosity or calcification. Compared with other measurements, IFV had the most favorable receiver operating curve for the prediction of VC, with an area under the curve (AUC) of 0.78.ConclusionIFV measurement using 3-dimensional CT is significantly associated with VCs in transfemoral TAVR patients and might be superior to currently accepted parameters. IFV should be further studied among extended cohorts of TAVR treated patients as a novel tool for VC risk assessment prior to transfemoral TAVR.     

Interpreting the evidence: How accurate is coronary computed tomography angiography?

Coronary CT angiography (CTA) has evolved rapidly into a powerful diagnostic tool. More than 30 accuracy studies have reported accuracy results in >2000 patients. A meta-analysis of 29 studies found per-patient accuracy of 96% sensitivity, 74% specificity, 83% positive predictive value, and 94% negative predictive value. Several clinical studies support the safety and accuracy of coronary CTA for acute chest pain, after inconclusive stress testing, and in preoperative evaluation of patients before cardiac valve surgery. Accuracy studies suffer from selection bias because of the inclusion only of patients previously selected to undergo invasive angiography. This increases the incidence of true disease, raising apparent sensitivity and lowering negative predictive value, although the latter remains high at 94%. CTA has relatively low accuracy for the quantitative assessment of stenosis severity. CTA accuracy studies show high figures for sensitivity and negative predictive value in detection of coronary lesions. CTA less accurately shows lesion severity, and intermediate-grade lesions require physiologic evaluation. Clinical studies support the effectiveness of CTA for exclusion of significant coronary disease.     

Multidetector-row computed tomography of the coronary arteries: predictive value and quantitative assessment of non-calcified vessel-wall changes

The aim of this study was to quantitatively assess non-calcified coronary artery plaques and to determine their predictive value for the detection of coronary artery disease (CAD). A total of 179 patients underwent a calcium screening examination and a contrast-enhanced multidetector-row computed tomography angiography (MDCT) of the coronary arteries for various indications. The traditional calcium scores were evaluated and all examinations were reviewed for the presence of non-calcified plaques with an attenuation of 0–130 Hounsfield units (HU). The number, mean attenuation, and volume of these non-calcified plaques were recorded. All patients also underwent conventional catheter angiography. Coronary calcium was detected in 73% (131 of 179) of the patients. Overall incidence of purely non-calcified plaques was 30% (53 of 179). In 27% of the patients (48 of 179) no calcium was detected; however, 15% of these patients without calcifications showed non-calcified plaques (7 of 48). Significant correlations were found between the volume of calcified plaques, volume of non-calcified plaques, and total plaque volume. There were significant differences in plaque composition comparing different risk factor profiles and different stages of CAD. Volumetric assessment of non-calcified coronary artery plaques is feasible using contrast-enhanced MDCT. Screening for non-calcified plaques identifies patients with signs of CAD that are missed in a calcium screening examination.     

Role of 320-slice multislice computed tomography coronary angiography in the assessment of coronary artery stenosis

Objective

To evaluate the effectiveness of the multislice CT coronary angiography, as a non-invasive imaging tool in assessment of coronary artery stenosis.

Patients and methods

The study included 50 patients who were referred for MSCT coronary angiography followed by catheter coronary angiography. Patients with previous coronary bypass grafts and those with coronary stents were excluded. History of contrast allergy, renal impairment and severe chest conditions were exclusion criteria. The coronary angiographic CT studies were performed using a 320 CT scanner. The catheter coronary angiographic studies were performed via femoral arterial puncture. The results of CT angiography were compared with the gold standard catheter angiography.

Results

The positive predictive value and negative predictive value of MSCT coronary angiography in detection of coronary artery stenosis were 94% and 100%, respectively.

Conclusion

In conclusion, MSCT coronary angiography is a very helpful and rapid non-invasive coronary imaging modality that was able to detect and grade coronary artery stenosis better than other noninvasive examinations used to detect CAD, such as exercise stress testing. Due to its very high negative predictive value, it may eliminate the need for invasive coronary procedures in the presence of normal coronary imaging.     

Middle mesenteric artery: Angiographic and three-dimensional computed tomography findings

The middle mesenteric artery, also known as the third mesenteric artery, is a very rare anomaly. Several anatomical variations of middle mesenteric artery have been reported; in these reports, the right colic artery and/or middle colic artery often originate directly from the aorta. Here, we report a middle mesenteric artery in which the middle colic artery originated directly from the abdominal aorta. We also provide three-dimensional computed tomography and angiography findings and discuss anatomical and embryological considerations.     

Coronary CT angiography versus intravascular ultrasound for estimation of coronary stenosis and atherosclerotic plaque burden: A meta-analysis

BackgroundNumerous studies have compared coronary CT angiography (CTA) with quantitativecoronary angiography. However, the ability of coronary CTA to identify atherosclerosis and to accurately measure plaque and coronary area and volume measurements as compared with intravascular ultrasound (IVUS) has not been fully defined.ObjectiveWe sought to assess the ability of coronary CTA to quantify coronary and plaque measurements commonly performed with IVUS.MethodsWe searched multiple databases for diagnostic studies that directly compared coronary CTA and IVUS for coronary plaque detection, vessel luminal area, percentage of area stenosis, plaque area, and plaque volume. We used a bivariate mixed-effects binomial regression model to pool test sensitivity and specificity for detection of any coronary plaque.ResultsForty-two studies that evaluated 1360 patients (75% men; mean age, 59 years) were identified. No significant difference was found between coronary CTA and IVUS measurements of vessel lumen cross-sectional area, plaque area, percentage of area stenosis, or plaque volume within the overall cohort and no difference for the measurement of cross-sectional area (n = 5 studies) and plaque volume (n = 8 studies) among a subgroup that used automated or semiautomated measurement techniques. Sensitivity and specificity of coronary CTA to detect any plaque compared with IVUS were 93% and 92%, respectively, with an area under the receiver-operating curve of 0.97.ConclusionsCompared with IVUS, coronary CTA appears to be highly accurate for estimation of luminal area, percentage of area stenosis, plaque volume, and plaque area and for detection of plaque. The use of automated vessel and stenosis measurements appears promising in limited studies to date.     

Multislice computed tomography: angiographic emulation versus standard assessment for detection of coronary stenoses

The present study investigated angiographic emulation of multislice computed tomography (MSCT) (catheter-like visualization) as an alternative approach of analyzing and visualizing findings in comparison with standard assessment. Thirty patients (120 coronary arteries) were randomly selected from 90 prospectively investigated patients with suspected coronary artery disease who underwent MSCT (16-slice scanner, 0.5 mm collimation, 400 ms rotation time) prior to conventional coronary angiography for comparison of both approaches. Sensitivity and specificity of angiographic emulation [81% (26/32) and 93% (82/88)] were not significantly different from those of standard assessment [88% (28/32) and 99% (87/88)], while the per-case analysis time was significantly shorter for angiographic emulation than for standard assessment (3.4 ± 1.5 vs 7.0 ± 2.5 min, P < 0.001). Both interventional and referring cardiologists preferred angiographic emulation over standard curved multiplanar reformations of MSCT coronary angiography for illustration, mainly because of improved overall lucidity and depiction of sidebranches (P < 0.001). In conclusion, angiographic emulation of MSCT reduces analysis time, yields a diagnostic accuracy comparable to that of standard assessment, and is preferred by cardiologists for visualization of results.     

Left anterior descending coronary artery myocardial bridging by multislice computed tomography: Correlation with clinical findings

Objective

To assess the relationship between left anterior descending (LAD) coronary artery myocardial bridging detected by 64-slice computed tomography (CT) and clinical findings.

Methods

221 consecutive patients were examined with coronary 64-slice CT angiography. 21 patients with coronary stenosis >50% were excluded. The length, depth, and luminal narrowing of LAD myocardial bridges during systole and diastole were measured. CT findings were compared with the treadmill ECG-stress test, and clinical symptoms.

Results

Myocardial bridges of the LAD were found in 23% of patients (51/221) (length, 14.9 ± 6.5 mm; depth, 2.6 ± 1.6 mm). A significant difference was noted between the LAD luminal diameter before the intramyocardial course and intramyocardially, for both diastole and systole (p < 0.001); with a higher diameter reduction of 27% for end-systole compared to end-diastole with 15% (p = 0.006). Systolic LAD intramyocardial luminal narrowing >50% was found in 3/25 (8%). 30/51 (59%) of bridges were “deep” (>2 mm myocardial depth), 21/51 (41%) were “superficial”. The prevalence of a positive ECG-stress tests for the anterior myocardial region was significantly higher in patients with LAD myocardial bridges (34/50; 68%) compared to those without (28/144; 19.4%) (p < 0.001). There was no difference between “superficial” and “deep” LAD myocardial bridges in regard to a positive treadmill ECG-stress test. Typical angina was rare with 6%.

Conclusion

LAD myocardial bridges are common findings and can possibly explain a positive exercise ECG-stress test for anterior myocardial ischemia. Intramyocardial LAD segments show mild-to-moderate luminal narrowing at rest, which is higher during end-systolic phase.     

冠状动脉CT血管成像和运动平板试验对冠心病患者的诊断比较

目的:评价冠状动脉CT血管成像(CCTA)和运动平板试验(TET)对冠心病的诊断价值。方法:以常规冠状动脉造影(CAG)为诊断冠心病(冠脉狭窄≥50%)的"金标准",对同期先后行TET、CCTA和CAG 3种检查的75例疑似冠心病患者进行回顾性分析,将其TET和CCTA的结果与CAG进行比较。结果:TET和CCTA诊断冠心病的敏感度分别为45.2%和90.5%,特异度为69.7%和93.9%,阳性预测值为65.5%和95.0%,阴性预测值为50.0%和88.6%,准确率为56.0%和92.0%,P<0.01。在冠状动脉血管水平CCTA对右冠状动脉、左主干、前降支、回旋支狭窄诊断的准确率分别为86.7%、100.0%、88.0%和76.0%。冠心病患者中TET诊断阳性率与病变血管支数呈正相关(r=0.440,P=0.004);冠心病患者TET诊断结果阳性与阴性仅与血管狭窄程度≥75%狭窄的节段数目有统计学差异(P=0.016)。结论:CCTA诊断冠心病较TET有更高的诊断准确性和较低的诊断假阳性和假阴性,对有症状的疑诊冠心病患者CCTA的诊断具有更重要作用。     

Effect of a calcium deblooming algorithm on accuracy of coronary computed tomography angiography

BackgroundCoronary artery calcification is a significant contributor to reduced accuracy of coronary computed tomographic angiography (CTA) in the assessment of coronary artery disease severity. The aim of the current study is to assess the impact of a prototype calcium deblooming algorithm on the diagnostic accuracy of CTA.Methods40 patients referred for invasive catheter angiography underwent CTA and invasive catheter angiography. The CTA were reconstructed using a standard soft tissue kernel (CTA_STAND) and a deblooming algorithm (CTA_DEBLOOM). CTA studies were read with and without the deblooming algorithm blinded to the invasive coronary angiogram findings. Sensitivity, specificity, accuracy, positive predictive value and negative predictive value for the detection of stenosis ≥50% or ≥70% were evaluated using quantitative coronary angiography as the reference standard. Image quality was assessed using a 5-point scale, and the presence of image artifact recorded.ResultsAll studies were diagnostic with 548 segments available for evaluation. Image score was 3.64 ± 0.72 with CTA_DEBLOOM, versus 3.56 ± 0.72 with CTA_STAND (p = 0.38). CTA_DEBLOOM had significantly less calcium blooming artifact than CTA_STAND (12.5% vs. 47.5%, p = 0.001). Based on a 50% stenosis threshold for defining significant disease, the Sensitivity/Specificity/PPV/NPV/Accuracy were 65.9/84.9/27.6/96.6/83.4 for CTA_DEBLOOM and 75.0/81.9/26.6/97.4/81.4 for CTA_STAND using a ≥50% threshold. CTA_DEBLOOM specificity was significantly higher than CTA_STAND (84.9% vs. 81.5%, p = 0.03), with no difference between the algorithms in sensitivity (p = 0.22), or accuracy (p = 0.15). These results remained unchanged when a stenosis threshold of ≥70% was used. Interobserver agreement was fair with both techniques (CTA_DEBLOOM k = 0.38, CTA_STAND k = 0.37).ConclusionIn this proof of concept study, coronary calcification deblooming using a prototype post-processing algorithm is feasible and reduces calcium blooming with an improvement of the specificity of the CTA exam.