Noninvasive cardiac imaging for the diagnosis of coronary artery disease in women.

To the Editor,

I read with interest the review article entitled “Noninvasive cardiac imaging for the diagnosis of coronary artery disease in women,” which was written by Canpolat et al. (1) and published in Anatol J Cardiol 2014; 14: 741-6. As presented there, noninvasive imaging techniques (TET, cardiac echocardiography, myocardial perfusion SPECT, and perfusion PET) are actually the most useful and easy-to-perform tests to evaluate functional or anatomical properties in the patients with suspected or known ischemic heart disease (IHD). These tests particularly offer the potential to identify women at increased IHD risk. Planar imaging (with Tc-99m labeled agents or Tl-201 chloride) may be performed, and it still used in daily practice but not routinely performed. It is only obtained in limited circumstances such as imaging at the bedside of acutely ill patients or instrumented patients (2). SPECT imaging, mostly apply simultaneously with gated, is preferably performed in daily practice because of its high sensitivity, specificity, diagnostic accuracy and reader’s confidence in the interpretation of MPS SPECT results. Gated MPS helps in defining the suspected artifacts, risk stratification of patients with known or suspected CAD, myocardial viability, and enhanced detection of multivessels disease (3). Finally, high-sensitivity dedicated cardiac camera systems aid in injecting lower doses for MPS SPECT with an effective radiation dose of less than 1 mSv without significant loss of accuracy (4). Medical literature contains several studies using novel dedicated cardiac imaging systems and acquisition methods. Nevertheless, this review article does not offer the innovation of nuclear cardiology field.

References used for myocardial perfusion imaging are old (the newest one was published in 2009), the information provided on nuclear cardiac studies is erroneous, with use of incorrect technical terminology. Therefore, it the authors seem to have not effectively mastered the subject. For example, the authors have identified that SPECT and PET as functional tests. Assuming myocardial perfusion is function, this definition is correct; however, the term of function in the nuclear cardiology implies the left ventricular functional data (including EF, EDV, and ESV) obtained by ECG-triggering studies (ERNA or gated study) rather than only perfusion imaging.

The sentence of “Also, technetium Tc 99m sestamibi (MIBI), thallous chloride TL-201 (thallium) and fluorodeoxyglucose are the most commonly used radioactive materials in nuclear medicine for cardiovascular system.” in the section of myocardial perfusion imaging techniques is also incorrect because F-18 fluorodeoxyglucose is not a perfusion agent; it is a metabolism agent, which is used to evaluate myocardial viability. In cardiac studies, PET perfusion agents (Rb-82, O-15 water, and NH-13) have several advantages in women, particularly those who are obese with slightly higher effective dose (5). This information has been obtained from the reference #24 in this paper (1). Notably, the authors have not presented any PET perfusion agent; the reason for this is unclear.

In figure 1, the meaning of “The statement TM should be corrected as ’ETT’“ could not be understood.

Finally, the novel knowledge in the field of nuclear cardiology, appropriate use criteria, and algorithms for diagnosing and follow-up in the women and men with IHD can be easily available from ASNC page (www.asnc.org) and PubMed. I believe that revision is necessary for the part of myocardial perfusion imaging techniques in this review article to prevent incorrect information from reaching junior inexperienced readers.