Is cardiac MRI adenosine stress perfusion imaging a more appropriate diagnostic tool for obese patients?

Abstract

Background Cardiac nuclear stress perfusion imaging is subject to artifact related to obesity, breast attenuation and diaphragm overlap. These factors are responsible for “false positive” results among patients undergoing evaluation for coronary atherosclerosis, leading to potentially unnecessary invasive coronary arteriography. Cardiac MRI adenosine stress perfusion imaging is unaffected by both obesity and breast tissue attenuation, resulting in sensitivity and specificity rates in excess of 90%. Accordingly, cardiac MRI adenosine stress perfusion imaging may be a more appropriate form of testing for obese patients. Methods Interrogation of the institutional cardiac MRI database revealed 110 patients who had undergone both cardiac nuclear stress perfusion imaging and cardiac MRI adenosine stress perfusion imaging studies, separated in time by no more than 3 months. Each type of perfusion imaging study was categorized as Normal (no ischemia) or Abnormal (evidence of ischemia). The Body Mass Index (BMI) was also extracted from the database for each patient. Concordance for the 2 tests was computed over a range of BMI values and graphically plotted for trend analysis. Patients were also grouped according to standard WHO bodyweight definitions: Normal (BMI 30 kg/m2) for statistical comparison of concordance. Results Concordance for nuclear and cardiac stress perfusion imaging studies was 61.5% for BMI 35 kg/m2. A one-way ANOVA was computed to compare concordance between the 2 tests for patients categorized as Normal (BMI 30). Obese patients had a statistically significant decreased concordance between both tests when compared to normal weight patients (p <0.05). Conclusions