Clinical Indications and Limitations

Kusai S. Aziz

The use of cardiac CT has significantly increased during the last few years because of advanced technology and the introduction of new generation 64-slice CT scans that enable higher spatial resolution and less motion artifact. Cardiac software has also advanced and made it much easier to calculate calcium scores and track coronary arteries and evaluate them in multiple orientations.

In 2006, the ACCF/ACR/SCCT/SCMR/ASNC/NASCI/SCAI/SIR published appropriateness criteria for both cardiac CT and cardiac MRI (Table 1, 2, 3, 4, 5, 6 and –Table 7).1 We recommend following these criteria since they represent the most evidence-based analysis of the rapidly increasing applications of this technology. However, it should be kept in mind that reimbursement of these studies by third-party payers remains very restricted. It should also be kept in mind that, considering the radiation exposure, cardiac CTA can not be recommended as a screening tool in middle age asymptomatic subjects.2

TABLE 5.1 Detection of CAD: Symptomatic

Indication		Appropriateness Criteria (Median Score)
Evaluation of Chest Pain Syndrome (Use of CT Angiogram)
1.	• Intermediate pre-test probability of CAD • ECG interpretable AND able to exercise	U (5)
2.	• Intermediate pre-test probability of CAD • ECG uninterpretable OR unable to exercise	A (7)
3.	• High pre-test probability of CAD	I (2)
Evaluation of Intra-Cardiac Structures (Use of CT Angiogram)
4.	• Evaluation of suspected coronary anomalies	A (9)
Acute Chest Pain (Use of CT Angiogram)
5.	• Low pre-test probability of CAD • No ECG changes and serial enzymes negative	U (5)
6.	• Intermediate pre-test probability of CAD • No ECG changes and serial enzymes negative	A (7)
7.	• High pre-test probability of CAD • No ECG changes and serial enzymes negative	U (6)
8.	• High pre-test probability of CAD • ECG—ST-segment elevation and/or positive cardiac enzymes	I (1)
9.	• “Triple rule out”—exclude obstructive CAD, aortic dissection, and pulmonary embolism • Intermediate pre-test probability for one of the above • ECG—no ST-segment elevation and initial enzymes negative	U (4)
Reprinted from Hendel RC, Patel MR, Kramer CM, et al. ACCF/ACR/SCCT/SCMR/ASNC/NASCI/SCAI/SIR 2006 appropriateness criteria for cardiac computed tomography and cardiac magnetic resonance imaging: a report of the American College of Cardiology Foundation Quality Strategic Directions Committee Appropriateness Criteria Working Group, American College of Radiology, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic Resonance, American Society of Nuclear Cardiology, North American Society for Cardiac Imaging, Society for Cardiovascular Angiography and Interventions, and Society of Interventional Radiology. J Am Coll Cardiol 2006;48:1475–97, with permission from Elsevier.