Cardiac CT (an approach)

Cardiac CT can be a more or less frequent examination faced in daily practice also depending on the institution and the CT scanner technology available. With technological advances and improved dose reduction techniques in the last decade, cardiac CT has become increasingly popular.

What is presented below is a “basic approach” for how to organize findings within a radiological report of a cardiac CT without claim for completeness. This does not cover all facets and the workup of every clinical question and every cardiac problem that might be investigated.

Recommendations, given in the Coronary Artery Disease - Reporting and Data System (CAD-RADS) document, created and published in 2016 as a collaborative effort by the Society for Cardiovascular Computed Tomography (SCCT), American College of Radiology (ACR), and North American Society for Cardiovascular Imaging (NASCI) has been taken into consideration by this approach.

Indications 

Similar to other organ-specific examinations it is important to understand that depending on the indication the acquisition protocol can vary but will include a coronary CTA in most circumstances.

Typical indications of cardiac CT include evaluation of the following:

Systematic review

The most common indication of cardiac CT consists of the assessment of the coronary arteries and thus a systematic evaluation should be included in every examination even if the respective clinical question for the cardiac CT is different.

A systematic review is essential and should comprise a meticulous inspection of the cardiac chambers, left ventricular outflow tract and coronary arteries including origin, course and variant anatomy as well as the cardiac veins on thin slice axial and multiplanar reformations, if possible also curved reformations.

Morphology
Visual assessment

The visual morphological assessment includes the following :

Quantitative assessment

Quantitative measurements usually depend on and are tailored to the clinical question. They can include the following measurements :

  • left and right ventricular size including diameter
  • atrial chamber size
  • coronary arteries
  • aortic root (at least systolic phase)
    • aortic root/sinus dimensions (cross-sectional area, circumference, derived diameters)
    • annulus dimensions (cross-sectional area, circumference, derived diameters)
    • height of coronary ostia
    • determination of fluoroscopic viewing angles
  • aortic valve
    • aortic valve calcification (in patients with a discordant result on echocardiography)
    • aortic valve area (AVA), regurgitant orifice area (ROA)
  • left atrial appendage ostium
Cardiac function

A left ventricular functional analysis can be only conducted on a retrospective gated cardiac CT and is more an optional part of the analysis:

  • contraction pattern: synchronous/dyssynchronous
Quantitative assessment

A quantitative assessment and depending on the clinical question may include the following:

Cardiac perfusion

A myocardial perfusion analysis can be only conducted after a respective acquisition preferably on a scanner with a wide detector row coverage during pharmacological stress hyperemia similar to SPECT/PET or MRI.

A quantitative myocardial attenuation analysis can then be performed in a semiautomatic fashion and depicted as perfusion maps and correlated to previously detected coronary lesions .

Common pathology

See also