Diagnostic accuracy of 320-row multidetector computed tomography coronary angiography to noninvasively assess in-stent restenosis

Assessment of bystander coronary artery disease in transcatheter aortic valve replacement (TAVR) patients using noncoronary-dedicated planning computed tomography angiography (CTA): diagnostic accuracy in a retrospective real-world cohort

AIM

To assess the diagnostic potential of a noncoronary-dedicated pre-TAVR CT angiography (CTA) conducted as a prospective ECG-gated scan without premedication and standard cardiac reconstructions in evaluating bystander coronary artery disease (CAD) against invasive coronary angiography (ICA) as the gold standard.

MATERIALS AND METHODS

This retrospective study included 232 patients who underwent both CTA and ICA as part of their pre-TAVR evaluation. Exclusion criteria included prior stent, pacemaker, coronary artery bypass, or valve surgery. Coronary arteries were analysed solely through thin-slice axial reconstructions, with observers blinded to ICA results. Stenosis was categorised as mild (< 50%), moderate (50%-69%), or severe (≥70%). Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were calculated for 50% and 70% diameter stenosis (DS) thresholds.

RESULTS

At the 50% DS threshold, CTA demonstrated 71% sensitivity, 74% specificity, 92% NPV, and 38% PPV. At the 70% DS threshold, results included 46% sensitivity, 91% specificity, 93% NPV, and 41% PPV. The highest vessel-specific NPV at 50% DS was for the left main (98%) and left anterior descending (LAD) (91%); at 70% DS, left main (LM) (98%) and left circumflex (LCX) (94%) showed the highest NPV. Image quality impacted NPV, with excellent or very good image quality linked to higher diagnostic performance.

CONCLUSION

Noncoronary-dedicated pre-TAVR CTA shows promise for ruling out significant CAD effectively and may act as a gatekeeper for ICA, aligning with typical coronary CT angiography (CCTA) outcomes.

Improvement of coronary stent visualization using ultra-high-resolution photon-counting detector CT

OBJECTIVES

This study aimed to compare the image quality and diagnostic performance of standard-resolution (SR) and ultra-high-resolution (UHR) coronary CT angiography (CCTA) based on photon-counting detector CT (PCD-CT) of coronary stents and explore the best reconstruction kernel for stent imaging.

METHODS

From July 2023 to September 2023, patients were enrolled to undergo CCTA using a dual-source PCD-CT system after coronary angioplasty with stent placement. SR images with a slice thickness/increment of 0.6/0.4 mm were reconstructed using a vascular kernel (Bv48), while UHR images with a slice thickness/increment of 0.2/0.2 mm were reconstructed using vascular kernels of six sharpness levels (Bv48, Bv56, Bv60, Bv64, Bv72, and Bv76). The in-stent lumen diameters were evaluated. Subjective image quality was also evaluated by a 5-point Likert scale. Invasive coronary angiography was conducted in 12 patients (25 stents).

RESULTS

Sixty-nine patients (68.0 [61.0, 73.0] years, 46 males) with 131 stents were included. All UHR images had significantly larger in-stent lumen diameter than SR images (p < 0.001). Specifically, UHR-Bv72 and UHR-Bv76 for in-stent lumen diameter (2.17 [1.93, 2.63] mm versus 2.20 [1.93, 2.59] mm) ranked the two best kernels. The subjective analysis demonstrated that UHR-Bv72 images had the most pronounced effect on reducing blooming artifacts, showcasing in-stent lumen and stent demonstration, and diagnostic confidence (p < 0.001). Furthermore, SR and UHR-Bv72 images showed a diagnostic accuracy of 78.3% (95% confidence interval [CI]: 56.3%-92.5%) and 88.0% (95%CI: 68.8%-97.5%), respectively.

CONCLUSION

UHR CCTA by PCD-CT leads to significantly improved visualization and diagnostic performance of coronary stents, and Bv72 is the optimal reconstruction kernel showing the stent struts and in-stent lumen.

CLINICAL RELEVANCE STATEMENT

The significantly improved visualization of coronary stents using ultra-high resolution CCTA could increase the diagnostic accuracy for in-stent restenosis and avoid unnecessary invasive quantitative coronary angiography, thus changing the clinical management for patients after percutaneous coronary intervention.

KEY POINTS

Coronary stent imaging is challenging with energy-integrating detector CT due to "blooming artifacts." UHR images using a PCD-CT enhanced coronary stent visualization. UHR coronary stent imaging demonstrated improved diagnostic accuracy in clinical settings.

Ultra-high-resolution photon-counting detector CT in evaluating coronary stent patency: a comparison to invasive coronary angiography

OBJECTIVES

To determine the diagnostic accuracy of ultra-high-resolution photon-counting detector CT angiography (UHR PCD-CTA) for evaluating coronary stent patency compared to invasive coronary angiography (ICA).

METHODS

Consecutive, clinically referred patients with prior coronary stent implantation were prospectively enrolled between August 2022 and March 2023 and underwent UHR PCD-CTA (collimation, 120 × 0.2 mm). Two radiologists independently analyzed image quality of the in-stent lumen using a 5-point Likert scale, ranging from 1 ("excellent") to 5 ("non-diagnostic"), and assessed all coronary stents for the presence of in-stent stenosis (≥ 50% lumen narrowing). The diagnostic accuracy of UHR PCD-CTA was determined, with ICA serving as the standard of reference.

RESULTS

A total of 44 coronary stents in 18 participants (mean age, 83 years ± 6 [standard deviation]; 12 women) were included in the analysis. In 3/44 stents, both readers described image quality as non-diagnostic, whereas reader 2 noted a fourth stent to have non-diagnostic image quality. In comparison to ICA, UHR PCD-CTA demonstrated a sensitivity, specificity, and accuracy of 100% (95% CI [confidence interval] 47.8, 100), 92.3% (95% CI 79.1, 98.4), and 93.2% (95% CI 81.3, 98.6) for reader 1 and 100% (95% CI 47.8, 100), 87.2% (95% CI 72.6, 95.7), and 88.6% (95% CI 75.4, 96.2) for reader 2, respectively. Both readers observed a 100% negative predictive value (36/36 stents and 34/34 stents). Stent patency inter-reader agreement was 90.1%, corresponding to a substantial Cohen's kappa value of 0.72.

CONCLUSIONS

UHR PCD-CTA enables non-invasive assessment of coronary stent patency with high image quality and diagnostic accuracy.

CLINICAL RELEVANCE STATEMENT

Ultra-high-resolution photon-counting detector CT angiography represents a reliable and non-invasive method for assessing coronary stent patency. Its high negative predictive value makes it a promising alternative over invasive coronary angiography for the rule-out of in-stent stenosis.

KEY POINTS

• CT-based evaluation of coronary stent patency is limited by stent-induced artifacts and spatial resolution. • Ultra-high-resolution photon-counting detector CT accurately evaluates coronary stent patency compared to invasive coronary angiography. • Photon-counting detector CT represents a promising method for the non-invasive rule-out of in-stent stenosis.

Characterizing the Heart and the Myocardium With Photon-Counting CT

ABSTRACT

Noninvasive cardiac imaging has rapidly evolved during the last decade owing to improvements in computed tomography (CT)-based technologies, among which we highlight the recent introduction of the first clinical photon-counting detector CT (PCD-CT) system. Multiple advantages of PCD-CT have been demonstrated, including increased spatial resolution, decreased electronic noise, and reduced radiation exposure, which may further improve diagnostics and may potentially impact existing management pathways. The benefits that can be obtained from the initial experiences with PCD-CT are promising. The implementation of this technology in cardiovascular imaging allows for the quantification of coronary calcium, myocardial extracellular volume, myocardial radiomics features, epicardial and pericoronary adipose tissue, and the qualitative assessment of coronary plaques and stents. This review aims to discuss these major applications of PCD-CT with a focus on cardiac and myocardial characterization.

2022 use of coronary computed tomographic angiography for patients presenting with acute chest pain to the emergency department: An expert consensus document of the Society of cardiovascular computed tomography (SCCT): Endorsed by the American College of Radiology (ACR) and North American Society for cardiovascular Imaging (NASCI)

Coronary computed tomography angiography (CTA) improves the quality of care for patients presenting with acute chest pain (ACP) to the emergency department (ED), particularly in patients with low to intermediate likelihood of acute coronary syndrome (ACS). The Society of Cardiovascular Computed Tomography Guidelines Committee was formed to develop recommendations for acquiring, interpreting, and reporting of coronary CTA to ensure appropriate, safe, and efficient use of this modality. Because of the increasing use of coronary CTA testing for the evaluation of ACP patients, the Committee has been charged with the development of the present document to assist physicians and technologists. These recommendations were produced as an educational tool for practitioners evaluating acute chest pain patients in the ED, in the interest of developing systematic standards of practice for coronary CTA based on the best available data or broad expert consensus. Due to the highly variable nature of medical care, approaches to patient selection, preparation, protocol selection, interpretation or reporting that differs from these guidelines may represent an appropriate variation based on a legitimate assessment of an individual patient's needs.

Cardiac CT blooming artifacts: clinical significance, root causes and potential solutions

This review paper aims to summarize cardiac CT blooming artifacts, how they present clinically and what their root causes and potential solutions are. A literature survey was performed covering any publications with a specific interest in calcium blooming and stent blooming in cardiac CT. The claims from literature are compared and interpreted, aiming at narrowing down the root causes and most promising solutions for blooming artifacts. More than 30 journal publications were identified with specific relevance to blooming artifacts. The main reported causes of blooming artifacts are the partial volume effect, motion artifacts and beam hardening. The proposed solutions are classified as high-resolution CT hardware, high-resolution CT reconstruction, subtraction techniques and post-processing techniques, with a special emphasis on deep learning (DL) techniques. The partial volume effect is the leading cause of blooming artifacts. The partial volume effect can be minimized by increasing the CT spatial resolution through higher-resolution CT hardware or advanced high-resolution CT reconstruction. In addition, DL techniques have shown great promise to correct for blooming artifacts. A combination of these techniques could avoid repeat scans for subtraction techniques.

In-Stent Restenosis

In-stent restenosis (ISR) remains a potential complication after percutaneous coronary intervention, even in the era of drug-eluting stents, and its treatment remains suboptimal. Neoatherosclerosis is an important component of the pathology of ISR and is accelerated in drug-eluting stents compared with bare-metal stents. Coronary angiography is the gold standard for evaluating the morphology of ISR, although computed tomography angiography is emerging as an alternative noninvasive modality to evaluate the presence of ISR. Drug-coated balloons and stent reimplantation are the current mainstays of treatment for ISR, and the choice of treatment should be based on clinical background and lesion morphology.

First In-Human Results of Computed Tomography Angiography for Coronary Stent Assessment With a Spectral Photon Counting Computed Tomography

OBJECTIVES

The aim of this study is to compare the image quality of in vivo coronary stents between an energy integrating detectors dual-layer computed tomography (EID-DLCT) and a clinical prototype of spectral photon counting computed tomography (SPCCT).

MATERIALS AND METHODS

In January to June 2021, consecutive patients with coronary stents were prospectively enrolled to undergo a coronary computed tomography (CT) with an EID-DLCT (IQon, Philips) and an SPCCT (Philips). The study was approved by the local ethical committee and patients signed an informed consent. A retrospectively electrocardiogram-gated acquisition was performed with optimized matching parameters on the 2 scanners (EID-DLCT: collimation, 64 × 0.625 mm; kVp, 120, automatic exposure control with target current at 255 mAs; rotation time, 0.27 seconds; SPCCT: collimation, 64 × 0.275 mm; kVp, 120; mAs, 255; rotation time, 0.33 seconds). The injection protocol was the same on both scanners: 65 to 75 mL of Iomeron (Bracco) at 5 mL/s. Images were reconstructed with slice thickness of 0.67 mm, 512 matrix, XCB (Xres cardiac standard) and XCD (Xres cardiac detailed) kernel, iDose 3 for EID-DLCT and 0.25-mm slice thickness, 1024 matrix, Detailed 2 and Sharp kernel, and iDose 6 for SPCCT. Two experienced observers measured the proximal and distal external and internal diameters of the stents to quantify blooming artifacts. Regions of interest were drawn in the lumen of the stent and of the upstream coronary artery. The difference (Δ S-C) between the respective attenuation values was calculated as a quantification of stent-induced artifacts on intrastent image quality. For subjective image quality, 3 experienced observers graded with a 4-point scale the image quality of different parameters: coronary wall before the stent, stent lumen, stent structure, calcifications surrounding the stent, and beam-hardening artifacts.

RESULTS

Eight patients (age, 68 years [interquartile range, 8]; all men; body mass index, 26.2 kg/m2 [interquartile range, 4.2]) with 16 stents were scanned. Five stents were not evaluable owing to motion artifacts on the SPCCT. Of the remaining, all were drug eluting stents, of which 6 were platinum-chromium, 3 were cobalt-platinum-iridium, and 1 was stainless steel. For 1 stent, no information could be retrieved. Radiation dose was lower with the SPCCT (fixed CT dose index of 25.7 mGy for SPCCT vs median CT dose index of 35.7 [IQ = 13.6] mGy; P = 0.02). For 1 stent, the internal diameter was not assessable on EID-DLCT. External diameters were smaller and internal diameters were larger with SPCCT (all P < 0.05). Consequently, blooming artifacts were reduced on SPCCT (P < 0.05). Whereas Hounsfield unit values within the coronary arteries on the 2 scanners were similar, the Δ S-C was lower for SPCCT-Sharp as compared with EID-DLCT-XCD and SPCCT-Detailed 2 (P < 0.05). The SPCCT received higher subjective scores than EID-DLCT for stent lumen, stent structure, surrounding calcifications and beam-hardening for both Detailed 2 and Sharp (all P ≤ 0.05). The SPCCT-Sharp was judged better for stent structure and beam-hardening assessment as compared with SPCCT-Detailed 2.

CONCLUSION

Spectral photon counting CT demonstrated improved objective and subjective image quality as compared with EID-DLCT for the evaluation of coronary stents even with a reduced radiation dose.

Added Value of Computed Tomography Virtual Intravascular Endoscopy in the Evaluation of Coronary Arteries with Stents or Plaques

Coronary computed tomography angiography (CCTA) is a widely used imaging modality for diagnosing coronary artery disease (CAD) but is limited by a high false positive rate when evaluating coronary arteries with stents and heavy calcifications. Virtual intravascular endoscopy (VIE) images generated from CCTA can be used to qualitatively assess the vascular lumen and might be helpful for overcoming this challenge. In this study, one hundred subjects with coronary stents underwent both CCTA and invasive coronary angiography (ICA). A total of 902 vessel segments were analyzed using CCTA and VIE. The vessel segments were first analyzed on CCTA alone. Then, using VIE, the segments were classified qualitatively as either negative or positive for in-stent restenosis (ISR) or CAD. These results were compared, using ICA as the reference, to determine the added diagnostic value of VIE. Of the 902 analyzed vessel segments, CCTA/VIE had sensitivity, specificity, accuracy, positive predictive value, and negative predictive value (shown in %) of 93.9/90.2, 96.2/98.2, 96.0/97.7, 70.0/83.1, and 99.4/99.0, respectively, in diagnosing ISR or CAD, with significantly improved specificity (p = 0.025), accuracy (p = 0.046), and positive predictive value (p = 0.047). VIE can be a helpful addition to CCTA when evaluating coronary arteries.

Health Care Monitoring and Treatment for Coronary Artery Diseases: Challenges and Issues

In-stent restenosis concerning the coronary artery refers to the blood clotting-caused re-narrowing of the blocked section of the artery, which is opened using a stent. The failure rate for stents is in the range of 10% to 15%, where they do not remain open, thereby leading to about 40% of the patients with stent implantations requiring repeat procedure within one year, despite increased risk factors and the administration of expensive medicines. Hence, today stent restenosis is a significant cause of deaths globally. Monitoring and treatment matter a lot when it comes to early diagnosis and treatment. A review of the present stent monitoring technology as well as the practical treatment for addressing stent restenosis was conducted. The problems and challenges associated with current stent monitoring technology were illustrated, along with its typical applications. Brief suggestions were given and the progress of stent implants was discussed. It was revealed that prime requisites are needed to achieve good quality implanted stent devices in terms of their size, reliability, etc. This review would positively prompt researchers to augment their efforts towards the expansion of healthcare systems. Lastly, the challenges and concerns associated with nurturing a healthcare system were deliberated with meaningful evaluations.

Subtracted Computed Tomography Angiography in the Evaluation of Coronary Arteries With Severe Calcification or Stents Using a 320-Row Computed Tomography Scanner

PURPOSE

Coronary computed tomography angiography (CCTA) has its limitations in evaluating arteries with stents or heavy calcification. This study compares the diagnostic performance of subtracted coronary computed tomography angiography (SCCTA) and nonsubtracted coronary computed tomography angiography (NSCCTA) in evaluating coronary artery disease (CAD) and in-stent restenosis (ISR).

MATERIALS AND METHODS

Twelve patients with stents and 20 patients with heavy coronary calcifications (total Agatston's score >400) underwent both SCCTA and invasive coronary angiography (ICA) with an interval of <3 months. Four subjects in the stented group also had heavy calcifications. Overall, 30 stented segments and 202 calcified segments were assessed to compare the diagnostic performance of SCCTA and NSCCTA in detecting ISR and CAD.

RESULTS

For the 30 stented segments, SCCTA/NSCCTA had a sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) (shown in %) of 66.7/100, 100/55.6, 96.7/60, 100/20, and 96.4/100 in diagnosing ISR, respectively. For the 202 calcified segments, SCCTA/NSCCTA had a sensitivity, specificity, accuracy, PPV, and NPV of 68.8/84.4, 97.6/76.5, 93.1/77.7, 84.6/40.3, and 94.3/96.3 in diagnosing CAD, respectively. For both stented and calcified segments, SCCTA was significantly superior to NSCCTA in specificity and accuracy. For the calcified segments, SCCTA was significantly superior to NSCCTA in PPV. There was no significant difference in the diagnostic performance of SCCTA between the stented and calcified segments.

CONCLUSIONS

The diagnostic accuracy and specificity of SCCTA are significantly superior to those of NSCCTA in evaluating CAD and ISR. SCCTA shows no statistical difference in its diagnostic performance between the stented and calcified segments.

Exploring the value of the double source CT angiography in diagnosing in-stent restenosis in lower limb artery

OBJECTIVES

This paper is aimed to explore the value of double source CT angiography (DS-CTA) for diagnosing in-stent restenosis in lower limb artery.

METHODS

From January 2016 to October 2018, all patients with stent in lower limb artery in our hospital were investigated by both DS-CTA and digital subtraction angiography. We measured the minimum lumen diameter and the diameter of the proximal normal vessels under each stent placement. The in-stent restenosis is defined as restenosis when the lumen area decreased by more than 50%. Digital subtraction angiography was performed within 1 week after DS-CT scan. Relationship between DS-CTA and digital subtraction angiography for diagnosing in-stent restenosis in lower limb artery was analyzed. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of DS-CTA for diagnosis of in-stent restenosis were analyzed with digital subtraction angiography as the reference standard. A total of 68 stents were placed in 51 patients. Among these patients, 27 cases were diagnosed as in-stent restenosis, presenting as endovascular contrast agent bias or crescent filling defect with the lumen area reducing over 50%, 6 cases of which had no significant in-stent restenosis by digital subtraction angiography analysis. Furthermore, 12 cases were occlusion, in which there was no high density contrast agent in stents; the remaining 41 stents were unobstructed and the contrast agent was filled well, 8 cases of which had significant in-stent restenosis by digital subtraction angiography analysis. In addition, four stents were deformed or distorted. Statistical analysis demonstrated the concentrations of DS-CTA and digital subtraction angiography in diagnosing in-stent restenosis for lower limb artery were closely related, and the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of DS-CTA were 72.4%, 84.6%, 77.8%, 80.5%, and 79.4%, respectively.

CONCLUSION

DS-CTA has a potential reliability for diagnosis of in-stent restenosis in lower limb artery, which may be further improved to be used for clinical interventional treatment of vascular diseases.

Diagnostic accuracy of dual-source and 320-row computed tomography angiography in detecting coronary in-stent restenosis: a systematic review and meta-analysis

BACKGROUND

Dual-source and 320-row computed tomography angiography (CTA) are increasingly used in diagnosing coronary in-stent restenosis (CISR).

PURPOSE

We sought to perform this meta-analysis to evaluate the diagnostic accuracy of dual-source computed tomography angiography (DSCTA) and 320-row CTA in detecting CISR when compared to invasive coronary angiography.

MATERIAL AND METHODS

Five scientific databases (PubMed, Embase, Scopus, The Cochrane Library, and Web of Science) were searched for research studies in which DSCTA and/or 320-row CTA were used as diagnostic tools for CISR, as recently as October 2017. Study inclusion, data extraction, systematic review, pooled meta-analysis, and subgroup analysis were conducted by two researchers independently.

RESULTS

Thirteen studies with 1384 assessable stents on DSCTA and five studies including 622 assessable stents on 320-row CTA were finally included. The sensitivity, specificity, and area under the curve (AUC) of DSCTA in diagnosing CISR were 0.92 (0.87-0.96), 0.91 (0.87-0.94), and 0.97 (0.95-0.98), respectively, and they were 0.91 (0.82-0.96), 0.95 (0.88-0.98), and 0.96 (0.94-0.97) for 320-row CTA. Subgroup analysis result suggested that DSTCA performed significantly better in CISR detection when the stent diameter was ≥ 3 mm compared to stent diameter < 3 mm: 0.98 (0.97-0.99) vs. 0.82 (0.79-0.86) with P < 0.05.

CONCLUSION

Our meta-analysis indicated both DSCTA and 320-row CTA had high diagnostic accuracy in detecting CISR and may serve as alternatives for further patient evaluation with CISR, especially for stent diameters ≥ 3 mm.

CTA Evaluation of Bioresorbable Scaffolds versus Metallic Coronary Stents – a Feasibility Study

Background: Computed tomography angiography (CTA) presents important limits in in-stent restenosis (ISR) evaluation in case of metallic coronary stents, due to the artifacts determined by stent struts, which alter in-stent plaque analysis. In case of bioresorbable scaffolds, stent strut resorption allows accurate evaluation of the vessel wall. Aim of the study: This study aims to compare the feasibility of CTA as a follow-up imaging method for ISR diagnosis following elective PTCA procedures, between bioresorbable scaffolds and metallic coronary stents.

Material and methods: We conducted a prospective, observational study on 73 patients with elective PTCA procedures in their medical history, in whom 113 stents were assessed via CTA in order to diagnose ISR. Based on stent type, the patients were divided into two groups: Group 1 – patients with bioresorbable vascular scaffolds (BVS) (n = 30); and Group 2 – patients with bare metal stents (BMS) (n = 43). Plaque analysis was possible only in the BVS group with a post-processing research-dedicated software, Syngo.via Frontier, which identified plaque morphology and virtual histology composition.

Results: After CTA evaluation, the BVS group presented a significantly higher incidence of severe coronary artery disease (CAD) (Group 1 – 73% vs. Group 2 – 30%, p <0.0001). The proximal part of the right coronary artery (RCA) presented a significantly higher percentage of metallic stents (14% BMS vs. 2% BVS, p = 0.0029). The comparative analysis of CTA sensibility for the visual evaluation of ISR identified a significantly higher percentage of diagnostic CT evaluations in the BVS group (Group 1 – 94% vs. Group 2 – 76.19%, p = 0.0006). CTA evaluation provided the most accurate results for the 3.0 and 3.5 mm devices. Regarding CTA sensibility for ISR diagnosis, the BVS group presented the smallest incidence of non-diagnostic CT evaluations.

Conclusions: CTA evaluation of bioresorbable scaffolds is superior to metallic stent assessment, the latter being influenced by numerous sources of error dependent mainly on the presence of the metal structure.

High-risk Plaque and Calcification Detected by Coronary CT Angiography to Predict Future Cardiovascular Events After Percutaneous Coronary Intervention

RATIONALE AND OBJECTIVES

The purpose of this study was to investigate whether high-risk plaque (HRP) and calcium assessed by coronary computed tomography (CT) could predict future cardiovascular events after second-generation drug-eluting stent (DES) placement.

MATERIALS AND METHODS

We analyzed 317 patients from December 2012 to April 2015 who underwent coronary CT followed by DES placement. HRP was defined as a plaque with positive remodeling and low attenuation or a plaque with a napkin-ring sign. Coronary calcium was assessed by Agatston score (AS). Patients were divided into three groups: low risk, HRP negative and AS <400; intermediate risk, HRP positive and AS ≥400; high risk, HRP positive and AS ≥400. The primary end point was a composite of all-cause mortality, myocardial infarction, fatal arrhythmia, or repeated revascularization. Kaplan-Meier analysis was used to estimate the distribution of time to events.

RESULTS

A total of 74 events (23%) occurred during a median follow-up of 25.8 months. Patients with primary end points had HRP more frequently (70% vs 51%, P = 0.003) and were more calcified (AS, 471 [interquartile range, 143-1614] vs 289 [interquartile range, 63-787]; P = 0.01) than patients without primary end points. The frequency of primary end point increased significantly in the intermediate- and high-risk patients (P = 0.0011). Multivariate analysis showed that the hazard ratio of the intermediate- and high-risk groups was 1.91 (95% confidence interval, 1.04-3.77; P = 0.037) and 2.66 (95% confidence interval, 1.27-5.73; P = 0.009), respectively.

CONCLUSION

Plaque and calcification analysis by coronary CT could predict future cardiovascular events after second-generation DES placement.

Diagnostic accuracy of dual-source computed tomography angiography for the detection of coronary in-stent restenosis: A systematic review and meta-analysis

We sought to perform a meta-analysis to comprehensively evaluate the diagnostic accuracy of dual-source computed tomography angiography (DSCTA) in detecting coronary in-stent restenosis (CISR) when compared to invasive coronary angiography. The stent-based research studies in which DSCTA was used as diagnostic tool for CISR, as recent as of October 2017, from several reputed scientific libraries (PubMed, Embase, Scopus, The Cochrane Library, and Web of Science) were evaluated. Study inclusion, data extraction, and risk bias assessment were conducted by two researchers independently. Pooled sensitivity (SEN), specificity (SPE), positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and area under summary receiver operator characteristics (SROC) curve (AUC) were calculated to assess the diagnostic value. In addition, heterogeneity and subgroup analysis were also carried out. A total of 13 studies with a total of 894 patients and 1384 assessable stents were included. The pooled results of DSCTA diagnosing CISR were as follows: SEN 0.92 (95% confidence interval [CI] 0.87-0.96), SPE 0.91 (95% CI 0.87-0.94), PLR 9.83 (95% CI 6.93-13.94), NLR 0.09 (95% CI 0.05-0.15), DOR 114.73 (95% CI 64.12-205.28), and AUC 0.97 (95% CI 0.95-0.98), respectively. The subgroup analysis result suggested that DSTCA performed significantly better in CISR detection when the stent diameter was ≥3 mm compared with the stent diameter <3 mm: (0.98 [0.97-0.99] vs 0.82 [0.79-0.86]) with P < .05. This study revealed that DSCTA has excellent diagnostic performance for detecting CISR and may serve as an alternative for further patient evaluation with CISR, especially for stent diameter ≥3 mm.

Diagnostic accuracy of in-stent restenosis using model-based iterative reconstruction at coronary CT angiography: initial experience

OBJECTIVE

The purpose of our study was to compare the diagnostic performance of coronary CT angiography (CTA) subjected to model-based iterative reconstruction (IR) or hybrid IR to rule out coronary in-stent restenosis.

METHODS

We enrolled 16 patients who harboured 22 coronary stents. They underwent coronary CTA on a 320-slice CT scanner. The images were reconstructed with hybrid IR (AIDR 3D) and model-based IR (FIRST) algorithms. We calculated the stent lumen attenuation increase ratio and measured the visible stent lumen diameter. Two blinded observers visually graded the likelihood of in-stent restenosis (lesions ≥ 50%) on hybrid IR and FIRST images.

RESULTS

The stent lumen attenuation increase ratio on FIRST- was lower than on AIDR 3D images (0.20 vs 0.32). The ratio of the visible- compared to the true stent lumen diameter was higher on FIRST- than AIDR 3D images (52.5 vs 47.5%). Invasive coronary angiography identified five stents (22.7%) with significant in-stent restenosis. The use of FIRST improved the sensitivity (60 vs 100%), positive (75.0 vs 83.3%) and negative predictive value (88.9 vs 100%) and the accuracy (86.4 vs 95.5%) for the detection of in-stent restenosis. Specificity was 94.1% for both reconstruction methods.

CONCLUSION

The model-based IR algorithm may improve diagnostic performance for the detection of in-stent restenosis. Advances in knowledge: Compared to hybrid IR, the new model-based IR algorithm reduced blooming artefacts and improved the image quality. It can be expected to improve diagnostic performance for the detection of in-stent restenosis on coronary CTA images.

Coronary Artery Stent Evaluation with Model-based Iterative Reconstruction at Coronary CT Angiography

RATIONALE AND OBJECTIVES

This study aims to compare the image quality of coronary artery stent scans on computed tomography images reconstructed with forward projected model-based iterative reconstruction solution (FIRST) and adaptive iterative dose reduction 3D (AIDR 3D).

MATERIALS AND METHODS

Coronary computed tomography angiography scans of 23 patients with 32 coronary stents were used. The images were reconstructed with AIDR 3D and FIRST. We generated computed tomography attenuation profiles across the stents and measured the width of the edge rise distance and the edge rise slope (ERS). We also calculated the stent lumen attenuation increase ratio (SAIR) and measured visible stent lumen diameters. Two radiologists visually evaluated the image quality of the stents using a 4-point scale (1 = poor, 4 = excellent).

RESULTS

There was no significant difference in the edge rise distance between the two reconstruction methods (P = 0.36). The ERS on FIRST images was greater than the ERS on AIDR 3D images (325.2 HU/mm vs 224.4 HU/mm; P <0.01). The rate of the visible stent lumen diameter compared to the true diameter on FIRST images was higher than that on AIDR 3D images (51.4% vs 47.3%, P <0.01). The SAIR on FIRST images was lower than the SAIR on AIDR 3D images (0.19 vs 0.30, P <0.01). The mean image quality scores for AIDR 3D and FIRST images were 3.18 and 3.63, respectively; the difference was also significant (P <0.01).

CONCLUSION

The image quality of coronary artery stent scans is better on FIRST than on AIDR 3D images.

Relationship between the Self-Rating Anxiety Scale score and the success rate of 64-slice computed tomography coronary angiography

OBJECTIVE

Computed tomography coronary angiography, a key method for obtaining coronary artery images, is widely used to screen for coronary artery diseases due to its noninvasive nature. In China, 64-slice computed tomography systems are now the most common models. As factors that directly affect computed tomography performance, heart rate and rhythm control are regulated by the autonomic nervous system and are highly related to the emotional state of the patient. The aim of this prospective study is to use a pre-computed tomography scan Self-Rating Anxiety Scale assessment to analyze the effects of tension and anxiety on computed tomography coronary angiography success.

METHODS

Subjects aged 18-85 years who were planned to undergo computed tomography coronary angiography were enrolled; 1 to 2 h before the computed tomography scan, basic patient data (gender, age, heart rate at rest, and family history) and Self-Rating Anxiety Scale score were obtained. The same group of imaging department doctors, technicians, and nurses performed computed tomography coronary angiography for all the enrolled subjects and observed whether those subjects could finish the computed tomography coronary angiography scan and provide clear, diagnostically valuable images. Participants were divided into successful (obtained diagnostically useful coronary images) and unsuccessful groups. Basic data and Self-Rating Anxiety Scale scores were compared between the groups.

RESULTS

The Self-Rating Anxiety Scale standard score of the successful group was lower than that of the unsuccessful group (P = 0.001). As the Self-Rating Anxiety Scale standard score rose, the success rate of computed tomography coronary angiography decreased.

CONCLUSIONS

The Self-Rating Anxiety Scale score has a negative relationship with computed tomography coronary angiography success.

ADVANCES IN KNOWLEDGE

Anxiety can be a disadvantage in computed tomography coronary angiography examination. The pre-computed tomography coronary angiography scan Self-Rating Anxiety Scale score may be a useful tool for assessing whether a computed tomography coronary angiography scan will be successful or not.

Utility of stress perfusion-cardiac magnetic resonance in follow-up of patients undergoing percutaneous coronary interventions of the left main coronary artery

To assess the accuracy of cardiac magnetic resonance (CMR) for the diagnosis of angiographic stenosis after percutaneous coronary intervention (PCI) of left main coronary artery (LMCA). Patients undergone in the last year PCI of unprotected LMCA and scheduled for conventional X-ray coronary angiography (CXA) were evaluated with stress perfusion CMR within 2 weeks before CXA. Main contraindications to CMR were exclusion criteria. Stress perfusion CMR was performed to follow a bolus of contrast Gadobutrol after 3 min of adenosine infusion. Between the 50 patients enrolled, only 1 did not finish the CMR protocol and 49 patients with median age 71 (65-75) years (38 male, 11 female) were analyzed. Between 784 coronary angiographic segments evaluated we found 75 stenosis or occlusions (prevalence 9.5%), but only 13 stenosis or occlusions in proximal segments (prevalence 6.6%). Patients with coronary stenosis (n = 12, 24%) showed a significantly (p = 0.002) higher prevalence of diabetes (7 of 12, 58%). At CMR examination, late gadolinium enhancement was present in 25 (51%), reversible perfusion defects in 12 (24%), and fixed perfusion defects in 6 subjects (12%). The only patient with LMCA restenosis resulted positive at perfusion CMR. The accuracy of stress perfusion CMR in diagnosis of coronary stenosis was higher when the analysis was performed only in proximal coronary arteries (95%, CI 86-99) compared to overall vessels (84%, CI 70-92). Stress perfusion CMR could strongly reduce the need for elective CXA in follow up of LMCA PCI and should be validated in further multicenter prospective studies.

Prevalence by Computed Tomographic Angiography of Coronary Plaques in South Asian and White Patients With Type 2 Diabetes Mellitus at Low and High Risk Using Four Cardiovascular Risk Scores (UKPDS, FRS, ASCVD, and JBS3)

The aim of this study was to explore the association between various cardiovascular (CV) risk scores and coronary atherosclerotic burden on coronary computed tomography angiography (CTA) in South Asians with type 2 diabetes mellitus and matched whites. Asymptomatic type 2 diabetic South Asians and whites were matched for age, gender, body mass index, hypertension, and hypercholesterolemia. Ten-year CV risk was estimated using different risk scores (United Kingdom Prospective Diabetes Study [UKPDS], Framingham Risk Score [FRS], AtheroSclerotic CardioVascular Disease [ASCVD], and Joint British Societies for the prevention of CVD [JBS3]) and categorized into low- and high-risk groups. The presence of coronary artery calcium (CAC) and obstructive coronary artery disease (CAD; ≥50% stenosis) was assessed using coronary CTA. Finally, the relation between coronary atherosclerosis on CTA and the low- and high-risk groups was compared. UKPDS, FRS, and ASCVD showed no differences in estimated CV risk between 159 South Asians and 159 matched whites. JBS3 showed a significant greater absolute CV risk in South Asians (18.4% vs 14.2%, p <0.01). Higher presence of CAC score >0 (69% vs 55%, p <0.05) and obstructive CAD (39% vs 27%, p <0.05) was observed in South Asians. South Asians categorized as high risk, using UKPDS, FRS, and ASCVD, showed more CAC and CAD compared than whites. JBS3 showed no differences. In conclusion, asymptomatic South Asians with type 2 diabetes mellitus more frequently showed CAC and obstructive CAD than matched whites in the population categorized as high-risk patients using UKPDS, FRS, and ASCVD as risk estimators. However, JBS3 seems to correlate best to CAC and CAD in both ethnicity groups compared with the other risk scores.

Automatic detection of aorto-femoral vessel trajectory from whole-body computed tomography angiography data sets

Extraction of the aorto-femoral vessel trajectory is important to utilize computed tomography angiography (CTA) in an integrated workflow of the image-guided work-up prior to trans-catheter aortic valve replacement (TAVR). The aim of this study was to develop a new, fully-automated technique for the extraction of the entire arterial access route from the femoral artery to the aortic root. An automatic vessel tracking algorithm was first used to find the centerline that connected the femoral accessing points and the aortic root. Subsequently, a deformable 3D-model fitting method was used to delineate the lumen boundary of the vascular trajectory in the whole-body CTA dataset. A validation was carried out by comparing the automatically obtained results with semi-automatically obtained results from two experienced observers. The whole framework was validated on whole body CTA datasets of 36 patients. The average Dice similarity indexes between the segmentations of the automatic method and observer 1 for the left ilio-femoral artery, the right ilio-femoral artery and the aorta were 0.977 ± 0.030, 0.980 ± 0.019, 0.982 ± 0.016; the average Dice similarity indexes between the segmentations of the automatic method and observer 2 were 0.950 ± 0.040, 0.954 ± 0.031 and 0.965 ± 0.019, respectively. The inter-observer variability resulted in a Dice similarity index of 0.954 ± 0.038, 0.952 ± 0.031 and 0.969 ± 0.018 for the left ilio-femoral artery, the right ilio-femoral artery and the aorta. The average minimal luminal diameters (MLDs) of the ilio-femoral artery were 6.03 ± 1.48, 5.70 ± 1.43 and 5.52 ± 1.32 mm for the automatic method, observer 1 and observer 2 respectively. The MLDs of the aorta were 13.43 ± 2.54, 12.40 ± 2.93 and 12.08 ± 2.40 mm for the automatic method, observer 1 and observer 2 respectively. The automatic measurement overestimated the MLD slightly in the ilio-femoral artery at the average by 0.323 mm (SD = 0.49 mm, p < 0.001) compared to observer 1 and by 0.51 mm (SD = 0.71 mm, p < 0.001) compared to observer 2. The proposed segmentation approach can automatically provide reliable measurements of the entire arterial accessing route that can be used to support TAVR procedures. To the best of our knowledges, this approach is the first fully automatic segmentation method of the whole aorto-femoral vessel trajectory in CTA images.

Cardiovascular Imaging: The Past and the Future, Perspectives in Computed Tomography and Magnetic Resonance Imaging

Today's noninvasive imaging of the cardiovascular system has revolutionized the approach to various diseases and has substantially affected prognostic information. Cardiovascular magnetic resonance (MR) and computed tomographic (CT) imaging are at center stage of these approaches, although 5 decades ago, these technologies were unheard of. Both modalities had their inception in the 1970s with a primary focus on noncardiovascular applications. The technical development of the various decades, however, substantially pushed the envelope for cardiovascular MR and CT applications. Within the past 10-15 years, MR and CT technologies have pushed each other in cardiac applications; and without the "rival" modality, neither one would likely not have reached its potential today. This view on the history of MR and CT in the field of cardiovascular applications provides insight into the story of success of applications that once have been ideas only but are at prime time today.

One-Year Clinical and Computed Tomography Angiographic Outcomes After Bioresorbable Vascular Scaffold Implantation During Primary Percutaneous Coronary Intervention for ST-Segment-Elevation Myocardial Infarction: The PRAGUE-19 Study

BACKGROUND

Bioresorbable vascular scaffolds (BVS) represent promising new technology, but data on their long-term outcomes in ST-segment-elevation myocardial infarction (STEMI) setting are missing. The aim was to analyze 1-year clinical and computed tomographic angiographic outcomes after BVS implantation in STEMI.

METHODS AND RESULTS

PRAGUE-19 is a prospective multicenter single-arm study enrolling consecutive STEMI patients undergoing primary percutaneous coronary intervention (pPCI) with intention-to-implant BVS. A total of 343 STEMI patients were screened during 15 months enrollment period, and 70 patients (mean age 58.6±10.3 and 74% males) fulfilled entry criteria and BVS was successfully implanted in 96% of them. All patients were invited for clinical and computed tomographic angiographic control 1 year after BVS implantation. Restenosis was defined as ≥75% area stenosis within the scaffolded segment. Three events were potentially related to BVS: 1 in-stent restenosis (treated 7 months after pPCI with drug-eluting balloon), 1 stent thrombosis (treated 2 weeks after pPCI by balloon dilatation-this patient stopped all medications after pPCI), and 1 sudden death at home 9 months after pPCI. Four other patients had events definitely unrelated to BVS. Overall, 1-year mortality was 2.9%. Computed tomographic angiography after 1 year was performed in 59 patients. All BVS were widely patent, and binary restenosis rate was 2% (the only restenosis mentioned above). Mean in-scaffold minimal luminal area was 7.8±2.6 mm(2), area stenosis was 20.1±16.3%, minimal luminal diameter was 3.0±0.6 mm, and diameter stenosis was 12.8±11.1%.

CONCLUSIONS

BVS implantation in STEMI is feasible and safe and offers excellent 1-year clinical and angiographic outcomes.

Comparative analysis between 64- and 320-slice spiral computed tomography in the display of coronary artery stents and diagnosis of in-stent restenosis

The aim of the present study was to compare the accuracy of 64-multi-slice spiral computed tomography (64-MSCT) and 320-MSCT in the display of coronary artery stents and diagnosis of in-stent restenosis. The data collected from the 64- and 320-MSCT coronary angiography of 93 patients following coronary artery stent implantation were retrospectively analyzed. The 64-MSCT group comprised 30 cases with 57 stents and the 320-MSCT group comprised 63 cases with 93 stents. The image quality, heart rate of the patients and the radiation effective dose (ED) they were subjected to, were compared. Furthermore, the diagnostic abilities of 64-and 320-MSCT coronary angiography for in-stent restenosis were evaluated using invasive coronary angiography results as the gold standards. Statistically significant differences were observed in the heart rate and ED of the patients from the two groups (P<0.05), but no significant difference was identified in the accuracy index (P>0.05). The sensitivity, specificity, positive and negative predictive value and accuracy of the 64-MSCT group were found to be 100% (7/7), 93.94% (31/33), 77.78% (7/9), 100% (31/31) and 95% (38/40), respectively, and those in the 320-MSCT group were found to be 100% (16/16), 95.89% (70/73), 84.21% (16/19), 100% (70/70) and 96.63% (86/89), respectively. The present findings suggest that both 64-MSCT and 320-MSCT can be used for follow-up and curative effect evaluation following coronary stent implantation; however, 320-MSCT has fewer requirements of the patients' heart rate and uses a lower radiation dose.

Cardiac CT: atherosclerosis to acute coronary syndrome

Coronary computed tomographic angiography (CCTA) is a robust non-invasive method to assess coronary artery disease (CAD). Qualitative and quantitative assessment of atherosclerotic coronary stenosis with CCTA has been favourably compared with invasive coronary angiography (ICA) and intravascular ultrasound (IVUS). Importantly, it allows the study of preclinical stages of atherosclerotic disease, may help improve risk stratification and monitor the progressive course of the disease. The diagnostic accuracy of CCTA in the assessment of coronary artery bypass grafts (CABG) is excellent and the constantly improving technology is making the evaluation of stents feasible. Novel techniques are being developed to assess the functional significance of coronary stenosis. The excellent negative predictive value of CCTA in ruling out disease enables early and safe discharge of patients with suspected acute coronary syndromes (ACS) in the Emergency Department (ED). In addition, CCTA is useful in predicting clinical outcomes based on the extent of coronary atherosclerosis and also based on individual plaque characteristics such as low attenuation plaque (LAP), positive remodelling and spotty calcification. In this article, we review the role of CCTA in the detection of coronary atherosclerosis in native vessels, stented vessels, calcified arteries and grafts; the assessment of plaque progression, evaluation of chest pain in the ED, assessment of functional significance of stenosis and the prognostic significance of CCTA.

Diagnosing coronary artery disease with hybrid PET/CT: it takes two to tango

The noninvasive diagnosis of coronary artery disease (CAD) is a challenging task. Although a large armamentarium of imaging modalities is available to evaluate the functional consequences of the extent and severity of CAD, cardiac perfusion positron emission tomography (PET) is considered the gold standard for this purpose. Alternatively, noninvasive anatomical imaging of coronary atherosclerosis with coronary computed tomography angiography (CCTA) has recently been successfully implemented in clinical practice. Although each of these diagnostic approaches has its own merits and caveats, functional and morphological imaging techniques provide fundamentally different insights into the disease process and should be considered to be complementary rather than overlapping. Hybrid imaging with PET/CT offers the possibility to evaluate both aspects nearly simultaneously, and studies have demonstrated that such a comprehensive assessment results in superior diagnostic accuracy, better prognostication, and helps in guiding clinical patient management. The aim of this review is to discuss the value of stand-alone CCTA and PET in CAD, and to summarize the available data on the surplus value of hybrid PET/CT including its strengths and limitations.

A systematic review and economic evaluation of new-generation computed tomography scanners for imaging in coronary artery disease and congenital heart disease: Somatom Definition Flash, Aquilion ONE, Brilliance iCT and Discovery CT750 HD

BACKGROUND

Computed tomography (CT) is important in diagnosing and managing many conditions, including coronary artery disease (CAD) and congenital heart disease. Current CT scanners can very accurately diagnose CAD requiring revascularisation in most patients. However, imaging technologies have developed rapidly and new-generation computed tomography (NGCCT) scanners may benefit patients who are difficult to image (e.g. obese patients, patients with high or irregular heart beats and patients who have high levels of coronary calcium or a previous stent or bypass graft).

OBJECTIVE

To assess the clinical effectiveness and cost-effectiveness of NGCCT for diagnosing clinically significant CAD in patients who are difficult to image using 64-slice computed tomography and treatment planning in complex congenital heart disease.

DATA SOURCES

Bibliographic databases were searched from 2000 to February/March 2011, including MEDLINE, MEDLINE In-Process and Other Non-Indexed Citations, EMBASE, Cochrane Database of Systematic Reviews (CDSR), Cochrane Central Register of Controlled Trials (CENTRAL), Database of Abstracts of Reviews of Effects (DARE), NHS Economic Evaluation Database (NHS EED), Health Technology Assessment (HTA) database and Science Citation Index (SCI). Trial registers and conference proceedings were searched.

REVIEW METHODS

Systematic review methods followed published guidance. Risk of bias was assessed using QUADAS-2. Results were stratified by patient group. Summary sensitivity and specificity were calculated using a bivariate summary receiver operating characteristic, or random effects model. Heterogeneity was assessed using the chi-squared statistic and I(2)-statistic. Cost-effectiveness of NGCCT was modelled separately for suspected and known CAD, evaluating invasive coronary angiography (ICA) only, ICA after positive NGCCT (NGCCT-ICA), and NGCCT only. The cost-effectiveness of NGCCT, compared with 64-slice CT, in reducing imaging-associated radiation in congenital heart disease was assessed.

RESULTS

Twenty-four studies reported accuracy of NGCCT for diagnosing CAD in difficult-to-image patients. No clinical effectiveness studies of NGCCT in congenital heart disease were identified. The pooled per-patient estimates of sensitivity were 97.7% [95% confidence interval (CI) 88.0% to 99.9%], 97.7% (95% CI 93.2% to 99.3%) and 96.0% (95% CI 88.8% to 99.2%) for patients with arrhythmias, high heart rates and previous stent, respectively. The corresponding estimates of specificity were 81.7% (95% CI 71.6% to 89.4%), 86.3% (95% CI 80.2% to 90.7%) and 81.6% (95% CI 74.7% to 87.3%), respectively. In patients with high coronary calcium scores, previous bypass grafts or obesity, only per-segment or per-artery data were available. Sensitivity estimates remained high (> 90% in all but one study). In patients with suspected CAD, the NGCCT-only strategy appeared most cost-effective; the incremental cost-effectiveness ratio (ICER) of NGCCT-ICA compared with NGCCT only was £71,000. In patients with known CAD, the most cost-effective strategy was NGCCT-ICA (highest cost saving, dominates ICA only). The ICER of NGCCT only compared with NGCCT-ICA was £726,230. For radiation exposure only, the ICER for NGCCT compared with 64-slice CT in congenital heart disease ranged from £521,000 for the youngest patients to £90,000 for adults.

LIMITATIONS

Available data were limited, particularly for obese patients and patients with previous bypass grafts. All studies of the accuracy of NGCCT assume that the reference standard (ICA) is 100% sensitive and specific; however, there is some evidence that ICA may sometimes underestimate the extent and severity of stenosis. Patients with more than one criterion that could contribute to difficulty in imaging were often excluded from studies; the effect on test accuracy of multiple difficult to image criteria remains uncertain.

CONCLUSIONS

NGCCT may be sufficiently accurate to diagnose clinically significant CAD in some or all difficult-to-image patient groups. Economic analyses suggest that NGCCT is likely to be considered cost-effective for difficult-to-image patients with CAD, at current levels of willingness to pay in the NHS. For patients with suspected CAD, NGCCT only would be most favourable; for patients with known CAD, NGCCT-ICA would be most favourable. No studies assessing the effects of NGCCT on therapeutic decision making, or subsequent patient outcomes, were identified. The ideal study to address these questions would be a large multi-centre RCT. However, one possible alternative might be to establish a multicentre tracker study. High-quality test accuracy studies, particularly in obese patients, patients with high coronary calcium, and those with previous bypass grafts are needed to confirm the findings of our systematic review. These studies should include patients with multiple difficult to image criteria.

FUNDING

The National Institute for Health Research Health Technology Assessment programme. This project was funded by the HTA programme, on behalf of NICE, as project number 10/107/01.

Feasibility of coronary artery wall thickening assessment in asymptomatic coronary artery disease using phase-sensitive dual-inversion recovery MRI at 3T

OBJECTIVES

The purpose of this study was to (a) investigate the image quality of phase-sensitive dual-inversion recovery (PS-DIR) coronary wall imaging in healthy subjects and in subjects with known coronary artery disease (CAD) and to (b) investigate the utilization of PS-DIR at 3T in the assessment of coronary artery thickening in subjects with asymptomatic but variable degrees of CAD.

MATERIALS AND METHODS

A total of 37 subjects participated in this institutional review board-approved and HIPAA-compliant study. These included 21 subjects with known CAD as identified on multidetector computed tomography angiography (MDCT). Sixteen healthy subjects without known history of CAD were included. All subjects were scanned using free-breathing PS-DIR magnetic resonance imaging (MRI) for the assessment of coronary wall thickness at 3T. Lumen-tissue contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR) and quantitative vessel parameters including lumen area and wall thickness were measured. Statistical analyses were performed.

RESULTS

PS-DIR was successfully completed in 76% of patients and in 88% of the healthy subjects. Phase-sensitive signed-magnitude reconstruction, compared to modulus-magnitude images, significantly improved lumen-tissue CNR in healthy subjects (26.73±11.95 vs. 14.65±9.57, P<.001) and in patients (21.45±7.61 vs. 16.65±5.85, P<.001). There was no difference in image CNR and SNR between groups. In arterial segments free of plaques, coronary wall was thicker in patients in comparison to healthy subjects (1.74±0.27 mm vs. 1.17±0.14 mm, P<.001), without a change in lumen area (4.51±2.42 mm2 vs. 5.71±3.11mm2, P=.25).

CONCLUSIONS

This is the first study to demonstrate the feasibility of successfully obtaining vessel wall images at 3T using PS-DIR in asymptomatic patients with known variable degrees of CAD as detected by MDCT. This was achieved with a fixed subject-invariant planning of blood signal nulling. With that limitation alleviated, PS-DIR coronary wall MRI is capable of detecting arterial thickening and positive arterial remodeling at 3T in asymptomatic CAD.

Systematic review of the accuracy of dual-source cardiac CT for detection of arterial stenosis in difficult to image patient groups

PURPOSE

To assess the diagnostic performance of dual-source cardiac (DSC) computed tomography (CT) newer-generation CT instruments for identifying anatomically significant coronary artery disease (CAD) in patients who are difficult to image by using 64-section CT.

MATERIALS AND METHODS

A literature search comprised bibliographic databases (January 1, 2000, to March 22, 2011, with a pragmatic update on September 6, 2012), trial registries, and conference proceedings. Only studies using invasive coronary angiography as reference standard were included. Risk of bias was assessed (QUADAS-2). Results were stratified according to patient group on the basis of clinical characteristics. Summary estimates of sensitivity and specificity of DSC CT for detecting 50% or greater arterial stenosis were calculated by using a bivariate summary receiver operating characteristic or random-effects model.

RESULTS

Twenty-five studies reported accuracy of DSC CT for diagnosing CAD in difficult to image patients; in 22 studies, one of two CT units of the same manufacturer (Somatom Definition or Somatom Definition Flash) was used, and in the remaining three, a different CT unit of another manufacturer (Aquilion One) was used. The pooled, per-patient estimates of sensitivity were 97.7% (95% confidence interval [CI]: 88.0%, 99.9%) and 97.7% (95% CI: 93.2%, 99.3%) for patients with arrhythmias and high heart rates, respectively. The corresponding pooled estimates of specificity were 81.7% (95% CI: 71.6%, 89.4%) and 86.3% (95% CI: 80.2%, 90.7%), respectively. All data were acquired by using Somatom Definition. In two studies with Somatom and one study with Aquilion One, sensitivity estimates of 90% or greater were reported in patients with previous stent implantations; specificities were 81.7% and 89.5% for Somatom and 81.0% for Aquilion One. In patients with high coronary calcium scores, previous bypass grafts, or obesity, only per-segment or per-artery data were available. Sensitivity estimates remained high (>90% in all but one study), and specificities ranged from 79.1% to 100%. All data were acquired by using Somatom Definition.

CONCLUSION

DSC CT may be sufficiently accurate to diagnose clinically significant CAD in some or all difficult to image patients.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.13121136/-/DC1.

CT coronary angiography: coronary CT-flow quantification supplements morphological stenosis analysis

BACKGROUND

Our rationale was to evaluate whether a 64-slice CT scanner allows accurate measurement of computed tomographic (CT) changes in coronary artery flow profiles and whether CT flow measurements are suitable for classifying the significance and hemodynamic relevance of a stenosis and thereby supplement as a functional parameter for morphological stenosis analysis.

METHODS

A total of 50 patients prospectively underwent computed tomography coronary angiography (coronary CTA) in a multidetector CT scanner (Brilliance 64, Philips)±1 day before or after invasive coronary angiography (ICA). Immediately thereafter, 2 radiologists reviewed the imaging data to detect any vessel segments with morphology poorly evaluable by coronary CTA. A locally constant cyclical measurement was acquired in these coronary arteries in breath-hold technique during the passage of a 50ml bolus of contrast media. For analysis, time-density curves of the bolus passage were registered in the coronary artery and the aorta (internal reference), the up-slopes were determined and correlated with each other. The results were compared with the ICA findings.

RESULTS

47 of 50 CT flow measurements were evaluable. A good correlation was found between the degrees of stenosis and slope ratios in aorta and coronary artery (R(2)=0.92). The threshold corridor was 0.55-0.77 for distinguishing hemodynamically (≥70%) from non-hemodynamically relevant stenoses.

CONCLUSIONS

CT-based coronary artery flow measurements (CTFM) correlate well with the angiographically determined degree of stenosis and can elevate by non-invasive means the diagnostic accuracy of coronary CTA. From both a clinically diagnostic and scientific standpoint, CTFM proves a suitable method for quantifying coronary blood flow.