Use of neutrophil/lymphocyte ratio as a marker in patients with suspicious diaphragmatic attenuation artifact

Objective: This study aimed to evaluate whether neutrophil/lymphocyte (N/L) ratio assists in the diagnosis of coronary artery disease (CAD) in patients with suspected diaphragmatic attenuation artifact (DAA) on myocardial perfusion SPECT (MP-SPECT). Material and Methods: A total of 255 patients undergoing coronary angiography between 2015-2020 due to unclear DAA of the inferior wall on MP-SPECT were included in this retrospective study. Patients were divided into two groups (CAD and non-CAD) according to angiographic images. Significant CAD was defined as ≥50% stenosis of coronary arteries feeding the inferior wall. White blood cell count, biochemical parameters, and risk factors for CAD were compared between the two groups. Results: There was no statistically significant difference between the two groups in terms of age (p = 0.055), gender (p = 0.482), and body mass index (p = 0.305). N/L ratio (OR = 1.397 p = 0.002 95% Cl = 1.128-1.732) and left ventricle ejection fraction (OR = 0.896 p = 0.023 95% Cl = 0.815-0.985) were independent risk factors for CAD in multivariate binary logistic regression analysis. Receiver Operating Characteristic (ROC) curve analysis showed that a cut-off value of ≥2 for N/L ratio predicted the presence of CAD (sensitivity=63.5%, specificity=60.7%, AUC=0.668, 95% CI=0.596 – 0.740, p<0.001). Conclusion: N/L ratio is a simple and accessible test and may increase the diagnostic accuracy of MP-SPECT for CAD in patients with suspicious diaphragmatic attenuation on MP-SPECT.

Position of Subcutaneous Implantable Cardioverter-Defibrillators and Possible Interference on Myocardial Perfusion Imaging

Implanted cardioverter-defibrillators can prevent sudden cardiac death in at-risk patients. In comparison with conventional transvenous systems, entirely subcutaneous implantable cardioverter-defibrillators have produced similar reductions in the rate of sudden cardiac death but with fewer sequelae. An infrequently reported drawback of subcutaneous devices, however, is the potential for generating attenuation artifact during nuclear myocardial perfusion imaging. We had concerns about potential attenuation artifact in a 65-year-old man with coronary artery disease but found that having positioned the pulse generator in the midaxillary zone avoided problems.