EXIT-CVD Project: Evidence Based Exit Strategies for the Cardiovascular Disease Continuum Trough Early Detection, Treatment and Evaluation

Adult patients with a positive conventional coronary CT angiography (CCTA) who are scheduled for clinically indicated invasive coronary angiography with intravascular ultrasound (IVUS) will undergo an additional PCCT acquisition for research purposes. PCCT datasets will be analyzed using a dedicated post-processing platform implementing artificial intelligence-based Quantitative Coronary CT (AI-QCT) algorithms for automated plaque quantification and characterization, including assessment of plaque burden, plaque composition, stenosis severity, and high risk plaque features. Conventional CCTA and PCCT images will be compared within the same patient to assess image quality, coronary stenosis, plaque burden and composition, high-risk plaque features, CAD-RADS classification, radiation exposure, and contrast medium volume.

Invasive coronary angiography and IVUS findings will serve as reference standards to evaluate the diagnostic accuracy and agreement of CT-derived measurements. The study will assess whether PCCT combined with AI-QCT provides improved coronary plaque characterization, diagnostic performance, and cardiovascular risk stratification compared with conventional CCTA, while potentially reducing radiation exposure and contrast medium requirements.

• Photon Counting Computed Tomography (PCCT) (Radiation): Participants will undergo an additional Photon Counting Computed Tomography (PCCT) coronary angiography acquisition for research purposes after a clinically performed conventional coronary CT angiography. The PCCT examination will be performed using an optimized low-dose acquisition protocol. PCCT images will be analyzed using a dedicated image post-processing platform incorporating artificial intelligence-based Quantitative Coronary CT (AI-QCT) algorithms for quantitative and qualitative assessment of coronary artery disease, including coronary stenosis, plaque burden, plaque composition, and high-risk plaque features. Image quality, radiation exposure, and contrast medium volume will also be assessed.

Primary outcomes

• Diagnostic performance of PCCT combined with AI-QCT compared with conventional CCTA [16 months]: Diagnostic performance of PCCT combined with AI-QCT for the detection and assessment of coronary artery disease, compared with conventional CCTA.

Secondary outcomes

• Signal-to-noise ratio (SNR) [16 months]: Signal-to-noise ratio measured on conventional CCTA and PCCT images
• Quantitative and qualitative coronary plaque characteristics measured by AI-QCT [16 months]: Plaque burden, plaque composition, and high-risk plaque features measured by AI-QCT on conventional CCTA and PCCT images.
• Radiation dose associated with conventional CCTA and PCCT [16 months]: Radiation dose recorded for conventional CCTA and PCCT acquisitions.
• CAD-RADS classification [16 months]: CAD-RADS classification assigned to conventional CCTA and PCCT datasets.
• Agreement between AI-QCT and IVUS measurements of coronary plaque [16 months]: Agreement between non-invasive AI-QCT-derived measurements and corresponding invasive IVUS measurements of coronary plaque, assessed using intraclass correlation coefficient (ICC).
• Incremental value of PCCT for cardiovascular risk stratification [16 months]: Evaluation of the incremental value of PCCT combined with AI-QCT compared with conventional CCTA for cardiovascular risk stratification and clinical decision making.
• Contrast-to-noise ratio (CNR) [16 months]: Contrast-to-noise ratio measured on conventional CCTA and PCCT images.

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* Adults (≥ 18 years)
* Patients with suspected or known CAD and a positive conventional coronary CT angiography requiring further invasive evaluation.
* Patients scheduled for clinically indicated invasive coronary angiography with IVUS assessment.
* Ability to under go an additional PCCT scan according to the study protocol
* Ability and willingness to provide written informed consent.

Exclusion Criteria:

* Contraindications to CT imaging or iodinated contrast media
* Severe renal impairment (eGFR <30 mL/min/1.73 m²)
* Pregnancy or breastfeeding.
* Hemodynamic instability or inability to undergo CT acquisition
* Significant arrhythmias impairing image acquisition quality.
* Inability to provide informed consent.