Systematic axial anatomy

A 4-level scan-through of the heart on axials — what to look at and what's normal at each level.

A practical 7-step approach to reading a cardiac CT — from the image-quality check through the segment-by-segment coronary read to extracardiac findings.

Don’t try to track tortuous coronaries on axial slices. Instead, use the axial views to systematically review cardiac and non-cardiac structures at four distinct levels.

1
Pulmonary artery level

Assess the aorta and pulmonary artery. Normal:

  • Ascending aorta < 40 mm
  • PA < 28 mm
2
Aortic valve level

Assess the aortic valve. Remember the “lucky 40” metric: 40 mm is the upper limit of normal for the aortic root, the left atrium, and the right ventricular outflow tract.

3
Mid-ventricular level

Evaluate the LV chamber size (normal < 55 mm) and wall thickness (normal < 11 mm). This level is also where you spot myocardial ischemia or infarction — dark, hypodense subendocardial regions that fail to pick up contrast.

4
Base of the heart

Determine coronary dominance by seeing which artery gives rise to the PDA. Also evaluate extracardiac structures — the liver (congestion, cysts) and the esophagus (hiatal hernias).

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Image quality: the 5 C's
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Artifacts — recognition & fixes