Cardiovascular Imaging
Core framework
Cardiovascular questions cluster into four buckets: coronary CT angiography, cardiac function and viability by MRI, aortic disease, and vascular emergencies. For coronary CTA, know CAD-RADS: 0 (no stenosis), 1 (1–24%), 2 (25–49%), 3 (50–69%), 4A (70–99% in one vessel), 4B (≥70% in three vessels or left main ≥50%), 5 (total occlusion), plus S (stent), G (graft), and N (non-diagnostic) modifiers. A calcium score above 400 predicts a high pretest likelihood and often makes CTA non-diagnostic due to blooming artifact.
Cardiac MR
Know the difference between delayed-enhancement imaging (scar/infarct, viability) and perfusion. Myocardium with <25% transmural delayed enhancement has a good chance of functional recovery after revascularization; >50% transmural involvement predicts little recovery. Also recognize myocarditis (subepicardial/midwall enhancement) versus infarction (subendocardial to transmural, respecting a coronary territory).
Aorta and vessels
Stanford type A dissection involves the ascending aorta and is a surgical emergency; type B spares the ascending aorta and is usually managed medically unless complicated (malperfusion, rupture, rapid expansion). Aneurysm repair thresholds: ascending ≥5.5 cm (lower with bicuspid valve or connective tissue disease), abdominal ≥5.5 cm in men and ≥5.0 cm in women.
Traps and rule of thumb
Traps: calling a dissection "type B" when the ascending aorta is involved; forgetting the left main is a 4B/5-level lesion regardless of other vessels; confusing cardiac sarcoid (patchy, often basal septum) with infarction.
Rule of thumb: in the aorta, "A is for Ascending = Automatic surgery."