Coronary vasospasm produces reversible perfusion defects observed during adenosine triphosphate stress myocardial single-photon emission computed tomography.

Background: Adenosine triphosphate stress thallium-201 single-photon emission computed tomography (ATP-SPECT) is useful for diagnosing coronary artery disease (CAD), although sometimes false positive results are observed. It has not been established whether a coronary spasm is responsible for the false positive findings during ATP-SPECT.

Hypothesis: We investigated whether coronary spasm is one of the factors which produces reversible defects on ATP-SPECT.

[Evaluation of the number of sampling step angles in SPECT Images: comparison between FBP and OS-EM reconstruction algorithms].

We compared filtered back projection (FBP) and ordered subset expectation maximization (OS-EM) reconstruction algorithms to examine the effects of sampling step angle on SPECT image reconstruction. Image sampling was compared between conditions of constant total sampling time (16 min) and constant sampling time (40 sec) for each step with angles of 3, 5, 7.5, and 10 degrees.