Fewer women than men have positive SPECT and PET cardiac findings among patients with no history of heart disease

A lower detection rate of coronary artery disease (CAD) has been reported f or SPECT imaging in women, despite the fact that similar numbers of women a nd men die each year of heart disease. Ruling out instrumentation as a poss ible source of this tow detection rate for CAD in women could be important in determining the root cause of this difference. Methods: Patients were re ferred by cardiologists and randomized to PET or SPECT by the imaging cente r. A total of 210 patients (106 women, 104 men) were enrolled in this study , with 105 imaged by dual-isotope SPECT and 105 imaged by Rb-82 PET. Rest/s tress scanning was performed using dipyridamole. The effects of sex, prior history of GAD, and instrumentation on the detection of positive scans were determined using multiple logistic regression analysis with positive scans as the endpoint. Results: For the total study population, sex and prior hi story of GAD are significantly associated with positive scans, whereas imag ing modality and age are not. There was no significant interaction between sex and prior history of CAD. Men have 4.1-fold greater odds of having a po sitive nuclear scan than women, and patients with prior history of CAD have 5.2-fold greater odds of a positive scan after controlling for the confoun ding effects of age and imaging modality. In the subgroup of patients with no prior history of heart disease, men have 3.9-fold greater odds of a posi tive scan than women, and the odds ratio of a positive scan is 2.5-fold gre ater for PET than for SPECT There was no statistical difference in the numb er of positive scans by SPECT or PET, or positive scans by sex in patients with documented history of CAD. Conclusion: Fewer women than men have posit ive nuclear cardiology scans by both PET and SPECT, despite similar symptom s. Instrumentation characteristics alone do not account for this sex-based difference and suggest the possibility that early CAD may present different ly in women than in men.