Journal of cardiovascular computed tomography最新文献

Background: Coronary CT angiography (CCTA) is a key non-invasive tool for evaluating coronary artery disease (CAD). While energy-integrating detector CT (EID-CT) offers high negative predictive value (NPV), its positive predictive value (PPV) is limited in heavily calcified vessels. Photon-counting detector CT (PCD-CT), with higher spatial resolution and reduced blooming, may enhance diagnostic performance. Current PCD-CT systems provide both standard-resolution (SR) and ultra-high-resolution (UHR) modes, but the clinical impact of these modes remains under investigation.

Objectives: To compare the diagnostic accuracy and image quality of SR-PCD-CT versus EID-CT in quantifying coronary stenosis, using quantitative coronary angiography (QCA) as reference.

Materials and methods: In this prospective, single-centre study, 21 patients (5 women, mean age 71.5 years) with suspected CAD underwent CCTA with both EID-CT and SR-PCD-CT prior to QCA. A total of 301 coronary segments were assessed for stenosis severity, with ≥50 ​% stenosis deemed significant. Image quality was graded using a 5-point scale.

Results: No significant differences in percentage diameter stenosis (%DS) were found between imaging techniques (p ​= ​0.20). Both EID-CT and SR-PCD-CT showed good agreement with QCA (AUC: PCD-CT 0.89, EID-CT 0.86). Specificity and NPV were high for both; sensitivity and PPV were moderate. SR-PCD-CT yielded higher image quality compared to EID-CT (p ​< ​0.001).

Conclusions: In standard resolution mode, PCD-CT offers excellent image quality for quantifying coronary stenosis at comparable diagnostic accuracy compared to EID-CT.

Background: Coronary artery disease (CAD) is common in patients with severe aortic stenosis (AS) and may impact transcatheter aortic valve replacement (TAVR) procedural and long-term outcomes. CT coronary angiography (CTA) and CT-derived fractional flow reserve (FFR_CT) are tools used to assess CAD. However, adoption in the TAVR population is hindered by safety concerns with nitroglycerin and beta-blockers. The safety, accuracy, and utility of CTA and FFR_CT optimised with these medications for TAVR have not been established.

Methods: This international, multi-center, prospective registry included severe AS patients referred for TAVR, assessed for CAD with CTA and FFR_CT. Patients all received nitroglycerin and beta-blockers as needed to optimise image quality. Severe ventricular dysfunction, recent syncope/heart failure, critical hemodynamics, or prior revascularization were excluded. Significant CAD was defined as CTA stenosis ≥50 ​% and FFR_CT≤0.75. Primary endpoint was per-patient sensitivity and negative predictive value (NPV) of CTA compared to invasive coronary angiography (ICA). Secondary endpoints included specificity and positive predictive value (PPV) of CTA and FFR_CT, safety, feasibility (non-evaluable rate), and the modelled potential of CTA ​+ ​FFR_CT to reduce pre-TAVR ICA.

Results: 327 patients (75.9 ​± ​9.7 years, 53 ​% male) underwent CTA. CTA was safe and well tolerated in nearly all patients, with transient hypotension in 4 (1.2 ​%). CTA was evaluable in 326 patients (99.7 ​%), with 9 (2.8 ​%) having a non-evaluable vessel. FFR_CT and ICA were performed in 110 (33.6 ​%) and 133 (40.7 ​%) patients, respectively. Per-patient sensitivity, specificity, NPV, and PPV of CTA were 100 ​%, 71.4 ​%, 100 ​%, and 75.9 ​% and per-vessel 82.7 ​%, 78.9 ​%, 92.3 ​%, and 59.9 ​%. FFR_CT improved specificity and PPV to 88.9 ​% and 88.0 ​% for per-patient and 95.1 ​% and 81.8 ​% for per-vessel analysis. Using a simulated triage model deferring ICA in patients with CTA <50 ​% or ≥50 ​% stenosis with FFR_CT >0.75, 267 patients (81.7 ​%) could potentially have avoided ICA.

Conclusion: Coronary CTA performed with nitroglycerin and selective use of beta-blockers is safe and effective for assessing CAD in stable severe AS patients. Combining CTA and FFR_CT enhances diagnostic accuracy, potentially reducing the need for invasive angiography and streamlining TAVR workup.

Background: High temporal resolution (TR) in CT is essential for reducing motion artifacts from rapidly moving structures like the heart. Although the conventional impulse method can measure TR, it requires specialized equipment to accelerate a sphere, which limits its practicality.

Objectives: This study aimed to develop and validate a simplified pendulum method for TR measurement and validate that it provides equivalent measurements to the conventional approach.

Methods: TR was measured using the proposed pendulum method and the conventional slingshot method. Fifty scans were acquired for each method at pitch factors (PF) of 0.8 and 1.2. TR was quantified using full width at half maximum (FWHM) and full width at tenth maximum (FWTM). Equivalence was evaluated with the two one-sided tests (TOST).

Results: The pendulum method demonstrated statistical equivalence to the slingshot method across all tested parameters. For PF 0.8, the FWHM was 0.55 ​± ​0.03 ​s for the pendulum method versus 0.54 ​± ​0.04 ​s for the slingshot method (TOST, p ​= ​0.005). At PF of 1.2, the FWHM was 0.15 ​± ​0.01 ​s for both methods, which were also statistically equivalent (TOST, p ​= ​0.021).

Conclusion: The pendulum method provides a simple, reproducible approach for TR measurement, facilitating parameter optimization in clinical and research imaging.

Background: Vascular inflammation is a key aspect of plaque vulnerability. Cross-sectional studies suggest that increased carotid perivascular adipose tissue (PVAT) attenuation on CTA, which is thought to reflect vascular inflammation, is associated with stroke.

Objectives: We investigated the predictive value of carotid PVAT attenuation for ischemic stroke and TIA in a longitudinal study of symptomatic patients with carotid plaque.

Methods: We included patients with recent TIA or stroke and a ≥2 ​mm carotid plaque with <70 ​% stenosis who underwent CTA and MRI and were clinically followed-up for 5 years. Mean PVAT attenuation (-190 to -30 Hounsfield Units (HU)) was quantified within a radial distance from the outer vessel wall equal to the vessel diameter on the CTA slice containing the thickest plaque. Cox proportional hazards models assessed associations with ipsilateral stroke and TIA risk. Predictive value was compared with intraplaque hemorrhage (IPH) and the European Carotid Surgery Trial (ECST) score using the C-index.

Results: Among 159 patients (74 ​% men; 69 (63-73) years), 11 ischemic strokes and 10 TIAs occurred over 5.1 (3.1-5.6) years. Increased PVAT attenuation was independently associated with ischemic stroke or TIA (HR: 3.21 per 10 HU increase, 95%CI:1.70-6.05) and ischemic stroke alone (HR: 5.60, 95%CI:1.93-16.31). PVAT attenuation alone predicted ischemic stroke or TIA (C-index: 0.71, 95%CI:0.70-0.73) and ischemic stroke alone (C-index: 0.78, 95%CI:0.63-0.93). Adding PVAT attenuation improved prediction beyond IPH (C-index: 0.66-0.68 to 0.81-0.84) and the ECST score (0.64-0.75 to 0.75-0.86, respectively).

Conclusion: In symptomatic patients, PVAT attenuation is an independent marker for ischemic stroke and TIA risk.

Background: Deep learning-based fractional flow reserve derived from coronary CT angiography (CT-FFR) enables noninvasive assessment of lesion-specific ischemia. Onsite CT-FFR systems provide near-real-time physiologic evaluation at the workstation, potentially reducing unnecessary invasive testing. This study evaluated the diagnostic performance of a novel onsite deep learning CT-FFR algorithm compared with invasive instantaneous wave-free ratio (iFR).

Methods: We retrospectively analyzed 44 patients (44 lesions) who underwent clinically indicated coronary CT angiography (CCTA) and invasive iFR. CT-FFR values were generated using an onsite deep learning algorithm (cFFR v6) 1-2 ​cm distal to visually identified stenoses. Physiologic significance was defined as CT-FFR ≤0.80 or iFR ≤0.89. Diagnostic performance metrics were calculated overall and within CCTA stenosis strata (<50 ​%, 50-70 ​%, >70 ​%). ROC analysis and Pearson correlation assessed discriminative ability and linear association. Additional comparative analyses evaluated diagnostic accuracy of CCTA ≥50 ​% and ≥70 ​% thresholds relative to iFR and quantified incremental diagnostic value of CT-FFR over CCTA alone.

Results: Of 44 lesions, 28 (63.6 ​%) were iFR-positive and 30 (68.2 ​%) were CT-FFR-positive. CT-FFR demonstrated a sensitivity of 89.3 ​%, specificity of 68.8 ​%, positive predictive value of 83.3 ​%, negative predictive value of 78.6 ​%, and accuracy of 81.8 ​%; the area under the ROC curve was 0.79 (95 ​% CI, 0.66-0.92). CT-FFR and iFR showed a modest but significant correlation (r ​≈ ​0.37). Performance remained favorable in moderate (40-70 ​%) stenoses (AUC 0.73) and severe (>70 ​%) stenoses (AUC 0.84). In contrast, CCTA ≥50 ​% and ≥70 ​% thresholds showed limited discriminatory ability versus iFR (AUC 0.44 and 0.52, respectively). Compared with CCTA alone, CT-FFR improved both sensitivity and specificity and substantially increased AUC across both thresholds.

Conclusion: The onsite deep learning CT-FFR algorithm demonstrated good diagnostic agreement with invasive iFR and maintained performance across stenosis severity categories, while providing clear incremental value over CCTA stenosis assessment alone. These findings support the feasibility of rapid, workstation-integrated physiologic assessment during CCTA interpretation. Larger multicenter studies are needed to validate these results and clarify the clinical role of onsite CT-FFR.