Cardiac CT (an approach)
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At the time the article was created Joachim Feger had no recorded disclosures.View Joachim Feger's current disclosures
At the time the article was last revised Craig Hacking had the following disclosures:
- Philips Australia, Paid speaker at Philips Spectral CT events (ongoing)
These were assessed during peer review and were determined to not be relevant to the changes that were made.View Craig Hacking's current disclosures
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.
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:
preoperative assessment in the setting of non-coronary cardiac surgery
coronary artery disease (in patients with low to intermediate pretest probability)
visualization of cardiac veins
visualization of pulmonary veins
ascending aortic/aortic root aneurysm
aortic valve disease
preprocedural planning and postprocedural follow-up of structural heart disease
imaging of cardioembolic disease
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.
The visual morphological assessment includes the following 1-8:
cardiac situs, position, cardiac chambers and connections
congenital anomalies (e.g. atrial and ventricular septal defects)
cardiac chamber morphology
coronary artery morphology
absent or hypoplastic coronary artery
anomalous coronary ostium, ectopic origin, split origins, single coronary artery
anomalous posterior descending artery (PDA) from the left anterior descending artery (LAD)
stenosis grading in vessels >1.5 mm in diameter
based on luminal diameter stenosis (SCCT classification)
none, minimal, mild, moderate, severe, occlusion
location based on the AHA 15 segment model 2
vulnerable or high-risk plaque
additional coronary findings
diffuse or partial arterial mural thickening
coronary pseudotumor formation
valvular and subvalvular calcifications (absent, mild, moderate, severe)
other cardiac findings
extracardiac findings (adjacent mediastinal and pulmonary structures)
Quantitative measurements usually depend on and are tailored to the clinical question. They can include the following measurements 6,7:
left and right ventricular size including diameter
semiautomatic stenosis quantification
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 calcification (in patients with a discordant result on echocardiography)
aortic valve area (AVA), regurgitant orifice area (ROA)
left atrial appendage ostium
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
A quantitative assessment and depending on the clinical question may include the following:
end-systolic volume index (ESVI) [mL/m2]
stroke volume index (SVI) [mL/m2]
left ventricular mass index [g/m2]*
regional wall motion abnormalities: localization according to the 17 segment model
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 7.
cardiac vein pathology (cardiac vein stenosis or occlusion)
pulmonary vein pathology (pulmonary vein stenosis or occlusion)
and many more….