Cardiac computerized tomography (CT)

• Cardiac Computed Tomography (CT)
  • cardiac CT uses x-rays to build up 3D images of the heart
  • CT imaging of the heart can be performed either with or without intravenous contrast agents
  • as with cardiac magnetic resonance (CMR), following acquisition, the CT datasets can be reformatted in any orientation and can be viewed as cine loops for functional analysis of ventricular function
  • software allows semi-automated extraction of the coronary arteries and the production of 3D volumetric datasets
  • total scan time for a cardiac CT is about 15 minutes

Notes:

• CT provides rapid, high quality imaging of the coronary arteries not matched by any other non-invasive technique and is the only technique able to provide a coronary artery calcium score (CACS)
  • presence of coronary artery calcium is associated with plaque burden - however, it is not a marker of plaque vulnerability
    • despite this limitation the CACS gives an insight to the patient's level of cardiovascular disease risk and is helpful for guiding interventions or prevent coronary artery disease (2,3)
      
      
    • ACC/AHA guidelines on assessment of cardiovascular risk state that assessment of CACS may be considered based on a large number of observational studies:
      • with a CACS of >=300 Agatston units (or >=75th percentile for age, sex and ethnicity) supporting an upward revision in risk assessment (4)
        
        
• CT scanning is less claustrophobic than MRI and can be used in most patients who are precluded from having CMR

Reference:

• British Heart Foundation Factfile (January 2010). Cardiac imaging with MRI, CT and Nuclear techniques
• Reed GW et al. Angiographic predictors of adverse outcomes after percutaneous coronary intervention in patients with radiation associated coronary artery disease. Catheter Cardiovasc Interv. 2019 Jan 28;
• Chen Y et al. Comparison of Nongated Chest CT and Dedicated Calcium Scoring CT for Coronary Calcium Quantification Using a 256-Dector Row CT Scanner. Acad Radiol. 2019 Jan 23
• Goff DCet al. 2013 ACC/AHA guideline on the assessment of cardiovascular risk: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 2014;63:2935-2959