Noninvasive Functional Imaging Satisfactory for Detecting, Stratifying Obstructive CAD

Download this article's Factoid in PDF (& PPT for Gold Subscribers)

All 3 of the most commonly used noninvasive myocardial perfusion imaging modalities have high sensitivity for detecting obstructive coronary artery disease (CAD), according to results of a meta-analysis published in the May 8 issue of Journal of the American College of Cardiology. However, positron emission tomography (PET) and cardiac magnetic resonance (CMR) yield significantly higher diagnostic accuracy than single-photon emission computed tomography (SPECT).

Researchers led by Simon Schalla, MD, of Maastricht University Medical Center (Maastricht, The Netherlands), examined 166 studies including 17,901 patients published between 1990 and 2010 that involved the use of SPECT, CMR, or PET for the detection of obstructive CAD with coronary angiography as the reference standard.

SPECT studies comprised the largest group (n = 114), followed by CMR (n = 37) and PET (n = 15).

Similar Sensitivity, But Not Specificity

In pooled patient-based analyses, the 3 modalities had similar sensitivities, but a range of differences in specificity levels. Relative diagnostic odds ratios were calculated using meta-regression random effects models to evaluate significant differences in diagnostic performance between the 3 imaging methods. This demonstrated that CMR and PET had a significantly higher diagnostic accuracy than SPECT, on a patient and coronary territory basis (table 1).

Table 1. Sensitivity and Specificity Levels

The researchers also attempted to account for differences in study characteristics, broken into subgroups, which may have affected the diagnostic performance of the modalities. These characteristics included:

• Study year
• Mean age
• Study size
• Prevalence of CAD
• Prevalence of 3-vessel disease

Cutoff value for CAD on angiography

Overall, the diagnostic accuracy of PET and CMR in comparison with SPECT remained unchanged within the majority of subgroup analyses. PET was consistently associated with a higher pooled diagnostic odds ratio than CMR, whereas CMR demonstrated a higher pooled diagnostic odds ratio than SPECT. The study authors caution, however, that the power to detect relevant differences between subgroups could have been limited by small numbers of studies in specific subgroups.

Future Developments Likely to Improve Imaging Further

“Although SPECT is the most widely used and validated perfusion imaging technique, the advantage of PET over SPECT could be explained by its higher spatial resolution, excellent attenuation correction, and the use of different tracers,” the study authors write.

However, they also point out that despite its high sensitivity and specificity, “widespread use of PET is currently hampered by high costs and limited availability,” although some research suggests it may be cost effective.

CMR perfusion imaging, they add, “may provide an alternative without the use of ionizing radiation at a similar diagnostic accuracy as PET. We suggest that referring physicians consider these findings in the context of local expertise and infrastructure.”

Due to a lack of adequate studies reporting patient-based results, myocardial perfusion echocardiography and computed tomography (CT) myocardial perfusion imaging were not included in the meta-analysis, but the study authors say more data are needed on the diagnostic accuracy of these methods.

In addition, Dr. Schalla and colleagues say future technical developments are likely to improve the diagnostic performance of all 3 modalities by combined imaging of prior MI, coronary anatomy including plaque morphology, and myocardial perfusion.

 

---

Source:
Jaarsma C, Leiner T, Bekkers SC, et al. Diagnostic performance of noninvasive myocardial perfusion imaging using single-photon emission computed tomography, cardiac magnetic resonance, and positron emission tomography imaging for the detection of obstructive coronary artery disease: A meta-analysis. J Am Coll Cardiol. 2012;59:1719-1728.

Disclosures:

Dr. Schalla reports no relevant conflicts of interest.

Related Stories:

• Imaging Dominates ACC’s Top 5 Overused Procedures, Tests
• Mixed IMPACT for Cardiac MRI: More Sensitive Than SPECT, But Less Specific
• CT More Accurate Than MRI for Ruling Out Coronary Artery Disease

Click here for a listing of companies that provide support to the Cardiovascular Research Foundation, owner and operator of TCTMD.