[Clinical and prognostic value of X-ray based attenuation correction in post-stress myocardial perfusion SPECT]. / Valor clínico y pronóstico de la corrección de atenuación con rayos X en la SPECT de perfusión miocárdica post-estrés.

ABSTRACT

OBJECTIVE: The purpose of the study was to validate the X-ray-based attenuation correction technique applied to post-stress myocardial perfusion single photon emission computed tomography (SPECT). MATERIALS AND METHODS: Fifty-six patients with clinically suspected ischemic heart disease and no history of myocardial infarction or coronary revascularization were studied. All patients underwent a myocardial perfusion SPECT after exercise (38) or pharmacological stress (18). Mean clinical follow-up time was 18.6 months. Studies were assessed after reconstruction using the filtered back projection technique and after application of the X-ray-based attenuation correction technique, and the results obtained were related to the final clinical diagnosis. RESULTS: Eleven uncorrected studies were normal, while 45 studies showed perfusion defects. After attenuation correction, absence of significant perfusion defects was observed in 24 cases (42.9 % of all cases), and ischemic heart disease was finally ruled out in 22 cases. A greater study normalization rate was seen in men (p = 0.048; odds ratio = 2,923), but this fact was not shown to be significantly correlated to the following variables pre-test probability of ischemic heart disease, body mass index greater than 30, presence of cardiovascular risk factors or otherwise, and age. CONCLUSIONS: Application of the X-ray-based attenuation correction technique would have allowed for obviating the conduct of a resting perfusion study in 42.9 % of patients without apparently changing the diagnostic safety of the test. This fact was seen more frequently in men. This method seems to be both safe and time- and cost-effective.