Diagnostic accuracy of a modified subtraction coronary CT angiography method with short breath-holding time: a feasibility study

Predictive value of systemic inflammatory response index (SIRI) for complex coronary artery disease occurrence in patients presenting with angina equivalent symptoms

BACKGROUND

Currently, atherosclerotic cardiovascular disease is the major cause of mortality world-wide. Inflammatory processes are postulated to be a major driving force for coronary plaque initiation and progression and can be evaluated by simple inflammatory markers from whole blood count analysis. Among hematological indexes, systemic inflammatory response index (SIRI) is defined as a quotient of neutrophils and monocytes, divided by lymphocyte count. The aim of the present retrospective analysis was to present the predictive role of SIRI for coronary artery disease (CAD) occurrence.

METHODS

There were 256 patients (174 [68%] men and 82 [32%] women) in the median (Q1-Q3) age of 67 (58-72) years enrolled into retrospective analysis due to angina pectoris equivalent symptoms. A model for predicting CAD was created based on demographic data and blood cell parameters reflecting an inflammatory response.

RESULTS

In patients with single/complex coronary disease the logistic regression multivariable analysis revealed predictive value of male gender (odds ratio [OR]: 3.98, 95% confidence interval [CI]: 1.38-11.42, p = 0.010), age (OR: 5.57, 95% CI: 0.83-0.98, p = 0.001), body mass index (OR: 0.89, 95% CI: 0.81-0.98, p = 0.012), and smoking (OR: 3.66, 95% CI: 1.71-18.22, p = 0.004). Among laboratory parameters, SIRI (OR: 5.52, 95% CI: 1.89-16.15, p = 0.029) and red blood cell distribution width (OR: 3.66, 95% CI: 1.67-8.04, p = 0.001) were found significant.

CONCLUSIONS

Systemic inflammatory response index, a simple hematological index, may be helpful in patients with angina equivalent symptoms to diagnose CAD. Patients presenting with SIRI above 1.22 (area under the curve: 0.725, p < 0.001) have a higher probability of single and complex coronary disease.

Subtraction coronary CT angiography in patients with high heart rate

All the previous subtraction coronary CT angiography (CCTA) had strict heart rate (HR) inclusion criteria. In this study, a new subtraction method was applied to patients with various HR. The post-contrast scan time was respectively 3.5 s after ascending aorta peak enhancement while HR >80 bpm, 4 s while 65≤ HR ≤80 bpm and 4.5 s while HR <65 bpm. Forty-six patients who underwent the new subtraction protocol were enrolled and patients were stratified into the high HR group (≥70 bpm) and low HR group (<70 bpm). Eighteen patients with 15 severe calcification segments and 25 stent segments further received invasive coronary angiography (ICA). In all included patients, the coronary artery enhancement was compared between the high and low HR groups. In patients with ICA performed, the image quality improvement and diagnostic effectiveness for detection of significant coronary segments stenosis (>50%) were compared between the conventional CCTA and subtraction CCTA and between the high HR group and low HR group, respectively. All enrolled patients got sufficient coronary artery enhancement. In patients with ICA performed, receiver operating characteristic (ROC) curve analysis showed that the area under the curve (AUC) for the diagnosis of significant stenosis was 0.93 in subtraction CCTA and 0.73 in conventional CCTA (p < 0.05). Furthermore, there were no significant differences in image quality improvement, specificity, positive predictive value and accuracy between the high HR group and low HR group. The new subtraction CCTA method broadened the clinical availability for patients with high HR.

Diagnostic Improvements of Deep Learning-Based Image Reconstruction for Assessing Calcification-Related Obstructive Coronary Artery Disease

Objectives: The objective of this study was to explore the diagnostic value of deep learning-based image reconstruction (DLR) and hybrid iterative reconstruction (HIR) for calcification-related obstructive coronary artery disease (CAD) evaluation by using coronary CT angiography (CCTA) images and subtraction CCTA images.

Methods: Forty-two consecutive patients with known or suspected coronary artery disease who underwent coronary CTA on a 320-row CT scanner and subsequent invasive coronary angiography (ICA), which was used as the reference standard, were enrolled. The DLR and HIR images were reconstructed as CTA_DLR and CTA_HIR, and, based on which, the corresponding subtraction CCTA images were established as CTA_sDLR and CTA_sHIR, respectively. Qualitative images quality comparison was performed by using a Likert 4 stage score, and quantitative images quality parameters, including image noise, signal-to-noise ratio, and contrast-to-noise ratio were calculated. Diagnostic performance on the lesion level was assessed and compared among the four CCTA approaches (CTA_DLR, CTA_HIR, CTA_sDLR, and CTA_sHIR).

Results: There were 166 lesions of 86 vessels in 42 patients (32 men and 10 women; 62.9 ± 9.3 years) finally enrolled for analysis. The qualitative and quantitative image qualities of CTA_sDLR and CTA_DLR were superior to those of CTA_sHIR and CTA_HIR, respectively. The diagnostic accuracies of CTA_sDLR, CTA_DLR, CTA_sHIR, and CTA_HIR to identify calcification-related obstructive diameter stenosis were 83.73%, 69.28%, 75.30%, and 65.66%, respectively. The false-positive rates of CTA_sDLR, CTA_DLR, CTA_sHIR, and CTA_HIR for luminal diameter stenosis ≥50% were 15%, 31%, 24%, and 34%, respectively. The sensitivity and the specificity to identify ≥50% luminal diameter stenosis was 90.91% and 83.23% for CTA_sDLR.

Conclusion: Our study showed that deep learning–based image reconstruction could improve the image quality of CCTA images and diagnostic performance for calcification-related obstructive CAD, especially when combined with subtraction technique.

Subtraction improves the accuracy of coronary CT angiography for detecting obstructive disease in severely calcified segments

OBJECTIVE

To investigate the accuracy, diagnostic confidence, and interobserver agreement of subtraction coronary CT angiography (CCTA) versus invasive coronary angiography on 320-row CT in coronary segments with severe or non-severe calcification.

MATERIALS/METHODS

Sixty-four patients (33 men, 66.6 ± 8.2 years) with suspected coronary artery disease (CAD) were prospectively enrolled from October 2019 to June 2020. The cross-sectional circumferential extent of calcification was used to classify calcified segments as non-severely ( < 180°) or severely calcified ( ≥ 180°). Three independent, blinded radiologists evaluated the severity of coronary stenosis. Interobserver agreement was evaluated using Fleiss' kappa (κ). A multiple-reader multiple-case receiver operating characteristic (ROC) method was conducted, and diagnostic accuracy was measured using the mean areas under the ROC curves (AUCs), with ≥ 50% stenosis as a cut-off. Diagnostic confidence, diagnostic accuracy, and interobserver agreement were compared between CCTA with or without subtraction information in severely and non-severely calcified segments.

RESULTS

In cases with severe calcification (51 patients, 146 segments), CCTA with subtraction information achieved better diagnostic accuracy (per-patient AUC: 0.73 vs 0.57, p = 0.03; per-segment AUC: 0.85 vs 0.62, p = 0.01), diagnostic confidence (3.7 vs 2.6, p < 0.001), and interobserver agreement (κ: 0.59 vs 0.30). Diagnostic accuracy (per-patient AUC: 0.81 vs 0.93, p = 0.30; per-patient AUC: 0.79 vs 0.82, p = 0.54) was not increased in cases with non-severe calcification (13 patients, 190 segments).

CONCLUSIONS

CCTA with subtraction information achieved better diagnostic accuracy in cases of severe calcification (circumferential extent ≥ 180°). However, for non-severe calcification (circumferential extent < 180°), the effect of calcium subtraction was unclear, as it did not improve diagnostic accuracy.

KEY POINTS

• Subtraction coronary CT angiography achieves better diagnostic accuracy, higher diagnostic confidence, and increased interobserver agreement for severe calcification (circumferential extent ≥ 180°). • Calcium subtraction does not improve the diagnostic accuracy of coronary CT angiography for calcification with a circumferential extent of < 180°.

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.

Modified Subtraction Coronary CT Angiography with a Two-Breathhold Technique: Image Quality and Diagnostic Accuracy in Patients with Coronary Calcifications

OBJECTIVE

To evaluate a modified subtraction coronary computed tomography angiography (CCTA) technique with a two-breathhold approach in terms of image quality and stenosis grading of calcified coronary segments and in the detection of significant coronary stenosis in segments with severe calcification.

MATERIALS AND METHODS

The institutional board approved this study, and all subjects provided written consent. A total of 128 patients were recruited into this trial, of which 32 underwent subtraction CCTA scans and invasive coronary angiography (ICA). The average Agatston score was 356 ± 145. In severely calcified coronary segments, the presence of significant (> 50%) stenosis was assessed on both conventional CCTA and subtraction CCTA images, and the results were finally compared with ICA findings as the gold standard.

RESULTS

For severely calcified segments, the image quality in conventional CCTA significantly improved from 2.51 ± 0.98 to 3.12 ± 0.94 in subtraction CCTA (p < 0.001). In target segments, specificity (70% vs. 87%; p = 0.005) and positive predictive value (61% vs. 79%, p < 0.01) were improved using subtraction CCTA in comparison with conventional CCTA, with no loss in the negative predictive value. The segment-based diagnostic accuracy for detecting significant stenosis was significantly better in subtraction CCTA than in conventional CCTA (area under the receiver operating characteristic curve, 0.94 vs. 0.85; p = 0.03).

CONCLUSION

This modified subtraction CCTA method showed lower misregistration and better image quality in patients with limited breathhold capability. In comparison with conventional CCTA, modified subtraction CCTA would allow stenosis regrading and improve the diagnostic accuracy in coronary segments with severe calcification.

Clinical utility of coronary computed tomography angiography in patients diagnosed with high-grade stenosis of the coronary arteries

OBJECTIVES

We purposed to evaluate the reliability of coronary computed tomography angiography (CCTA) in patients with a CCTA finding of high-grade stenosis.

PATIENTS AND METHODS

Between May 2015 and March 2017, patients who underwent invasive coronary angiography (ICA) because of detection of high-grade stenosis by CCTA ( ≥ 70% stenosis of epicardial arteries or ≥ 50% of the left main coronary artery; Coronary Artery Disease Reporting and Data System grade 4 or 5) were selected for this study from our prospective registry cohort.

RESULTS

Among 646 eligible patients, only 263 (41%) patients were correctly diagnosed with significant coronary artery disease on ICA as same as CCTA findings. The per-vessel analysis revealed that 620 (68%) of 916 affected vessels had confirmed concordant significant stenosis between the CCTA and ICA results. The concordance rate was 49% among the segments with identified plaques in the per-segment analysis. Revascularization of the target vessel identified with severe stenosis by CCTA was performed in 228 (35%) patients. A logistic regression analysis revealed that smoking [odds ratio (OR): 1.59, 95% confidence interval (CI): 1.04-2.42, P = 0.03], taller height (OR: 1.02, 95% CI: 1.00-1.05, P = 0.016), and presence of typical symptoms of angina (OR: 1.86, 95% CI: 1.34-2.59, P < 0.001) were found to increase the probability of diagnostic concordance. A greater calcified segment involvement score (OR: 0.88, 95% CI: 0.82-0.94, P < 0.001) was associated with a lower diagnostic concordance.

CONCLUSION

The diagnostic discordance between CCTA and ICA was frequently observed in patients who were diagnosed with a CCTA finding of high-grade stenosis.

Comparing dual energy CT and subtraction CT on a phantom: which one provides the best contrast in iodine maps for sub-centimetre details?

OBJECTIVES

To compare contrast-to-noise ratios (CNRs) and iodine discrimination thresholds on iodine maps derived from dual energy CT (DECT) and subtraction CT (SCT).

METHODS

A contrast-detail phantom experiment was performed with 2 to 15 mm diameter tubes containing water or iodinated contrast concentrations ranging from 0.5 mg/mL to 20 mg/mL. DECT scans were acquired at 100 kVp and at 140 kVp+Sn filtration. SCT scans were acquired at 100 kVp. Iodine maps were created by material decomposition (DECT) or by subtraction of water scans from iodine scans (SCT). Matched exposure levels varied from 8 to 15 mGy. Iodine discrimination thresholds (C_r) and response times were determined by eight observers.

RESULTS

The adjusted mean CNR was 1.9 times higher for SCT than for DECT. Exposure level had no effect on CNR. All observers discriminated all details ≥10 mm at 12 and 15 mGy. For sub-centimetre details, the lowest calculated C_r was ≤ 0.50 mg/mL for SCT and 0.64 mg/mL for DECT. The smallest detail was discriminated at ≥4.4 mg/mL with SCT and at ≥7.4 mg/mL with DECT. Response times were lower for SCT than DECT.

CONCLUSIONS

SCT results in higher CNR and reduced iodine discrimination thresholds compared to DECT for sub-centimetre details.

KEY POINTS

• Subtraction CT iodine maps exhibit higher CNR than dual-energy iodine maps • Lower iodine concentrations can be discriminated for sub-cm details with SCT • Response times are lower using SCT compared to dual-energy CT.

Subtraction CT angiography improves evaluation of significant coronary artery disease in patients with severe calcifications or stents-the C-Sub 320 multicenter trial

OBJECTIVES

Diagnostic accuracy of conventional coronary CT angiography (CCTA_conv) may be compromised by blooming artifacts from calcifications or stents. Blooming artifacts may be reduced by subtraction coronary CT angiography (CCTA_sub) in which non-contrast and contrast CT data sets are subtracted digitally. We tested whether CCTA_sub in patients with severe coronary calcification or stents reduces the number of false-positive stenosis evaluations compared with CCTA_conv.

METHODS

In this study, 180 symptomatic patients scheduled for invasive coronary angiography (ICA) were prospectively enrolled and CT scanned (2013-2016) at three international centers. CCTA_conv, and CCTA_sub data sets were reconstructed. Target segments were defined as motion-free coronary segments with a suspected stenosis (> 50% of lumen) potentially due to blooming of either calcium or stents. Target segments were evaluated with respect to misregistration artifacts from the CCTA_sub reconstruction process, in which case evaluation was omitted. CCTA_sub and CCTA_conv were compared with ICA. Primary outcome measure was the frequency of false positives by CCTA_conv versus CCTA_sub to identify > 50% coronary stenosis by ICA on a per-segment level.

RESULTS

After exclusion of 76 patients, 104 (14% females) with mean age 67 years and median Agatston score 852 were included. There were 136 target segments with misregistration and 121 target segments without. Accuracy calculations in target segments without misregistration showed a reduction of the false positives from 72% [95% confidence interval (CI): 63-80%] in CCTA_conv to 33% (CI:25-42%) in CCTA_sub, at the expense of 7% (CI:3-14%) false negatives in CCTA_sub.

CONCLUSIONS

In severely calcified coronary arteries or stents, CCTA_sub reduces the false-positive rate in well-aligned, calcified or stent segments suspected of significant stenosis on CCTA_conv. Nevertheless, misregistration artifacts are frequent in CCTA_sub.

KEY POINTS

• A high calcium-score reduces the diagnostic accuracy in patients scanned with cardiac CT. • These patients would normally need an invasive angiogram for diagnosis. • In this prospective, multicenter study, subtraction CT, when evaluable, reduces false-positive stenosis evaluations. • Subtraction coronary CT angiography may, when evaluable, reduce excessive downstream testing.