Cardiovascular Imaging
What the exam tests
Cardiovascular imaging tests ischemic and structural heart disease, vascular emergencies, appropriateness, and radiation dose. Modalities include coronary CT angiography (CCTA), cardiac MRI, echocardiography, nuclear perfusion, and CT/MR angiography.
Core rules
- CCTA is best for low-to-intermediate pretest probability chest pain; it has high negative predictive value.
- CAD-RADS: 0 no plaque; 1 minimal (<25%); 2 mild (25-49%); 3 moderate (50-69%); 4 severe (70-99%); 5 occlusion. Moderate stenosis usually prompts functional assessment or FFR-CT.
- Cardiac MRI late gadolinium enhancement: subendocardial or transmural patterns suggest ischemic disease; mid-wall or epicardial patterns suggest nonischemic cardiomyopathy.
- Acute aortic syndrome is a CTA diagnosis; assess the entire aorta, including branch vessels.
Worked example
A 58-year-old with atypical chest pain and low pretest probability undergoes CCTA. The mid-LAD shows a 50-69% stenosis without high-risk plaque. Reasoning: this is CAD-RADS 3, moderate stenosis. The patient should receive guideline-directed medical therapy and consideration of functional testing (stress imaging or FFR-CT) rather than automatic catheter angiography. If the stenosis were 70-99%, it would be CAD-RADS 4 and warrant more aggressive evaluation.
Traps
Confusing CAD-RADS 2 with obstructive disease; overcalling stenosis in heavily calcified vessels; ignoring motion artifact; and failing to recognize that a normal CCTA does not exclude microvascular angina.
Key points
- CCTA has high negative predictive value in low-intermediate risk chest pain.
- CAD-RADS 3 means 50-69% stenosis and often needs functional correlation.
- LGE patterns help separate ischemic from nonischemic cardiomyopathy.
- CTA is first-line for suspected aortic dissection.