Myocardial perfusion scintigraphy: techniques, interpretation, indications and reporting

Abstract

Myocardial perfusion single photon emission-computed tomography (MPS) has been one of the most important and common non-invasive diagnostic cardiac test. Gated MPS provides simultaneous assessment of myocardial perfusion and function with only one study. With appropriate attention to the MPS techniques, appropriate clinical utilization and effective reporting, gated MPS will remain a useful diagnostic test for many years to come. The aim of this article is to review the basic techniques of MPS, a simplified systematic approach for study interpretation, current clinical indications and reporting. After reading this article the reader should develop an understanding of the techniques, interpretation, current clinical indications and reporting of MPS studies.

Figure 1

Normal myocardial perfusion SPECT (MPS) in a 55-year-old man referred because of positive exercise stress test. Both stress and rest images demonstrate normal radiotracer distribution. A mild decreased uptake in basal inferior wall and septum is normal due to membranous septum (white arrows). The top two rows are short-axis (SAX) images of the left ventricle at stress and the second row the corresponding SAX images at rest. The next two rows are vertical long-axis images (VLA) at stress and rest. The bottom two rows are horizontal long axis (HLA) at stress and rest.

Figure 2

Normal attenuation correction (AC) MPS in 62-year-old women was performed for risk assessment before vascular surgery. In the AC images the right ventricle is clearly visualized, not to be confused with right ventricular hypertrophy (white arrows). The normal apical thing is more severe in AC images, and sometimes appears as a true perfusion defect (red arrows).

Figure 3a

The size or extent of the myocardial perfusion in three different patients. Selected short-axis images (SAX) at stress and rest. Small size (less than 10% of the LV myocardium) reversible anterolateral wall perfusion defect (arrows).

Figure 3b

The size or extent of the myocardial perfusion in three different patients. Selected short-axis images (SAX) at stress and rest. Medium size (less than 20% of the LV myocardium) reversible perfusion defect involving inferior and inferolateral (arrows).

Figure 3c

The size or extent of the myocardial perfusion in three different patients. Selected short-axis images (SAX) at stress and rest. Large sized (more than 20%) of the LV myocardium involving almost entire LAD distribution (arrows).

Figure 4

The severity of the perfusion defect in 71-year-old male with typical anginal pain. The perfusion defect in the apical lateral wall is mild (white arrow), moderate in the mid lateral wall (red arrow) and severe in the basal lateral wall (yellow arrow). For details please refer to the text.

Figure 5

A 50-year-old male with atypical chest pain. The stress SAX images show mild inferior wall perfusion defect (white arrows) that nearly normalized on rest images. Stress-prone imaging shows normal perfusion along the inferior wall (red arrows), this finding is consistent with attenuation artifact by subdiaphragmatic tissue.

Figure 6

Shifting breast attenuation in 60-year-old women came with chest pain, the MPS was performed with dipyridmale because patient could not exercise owing to severe arthritis. Stress NAC images show anterior wall perfusion defect (red arrows) with normalization at rest. In the AC images (lower row) the perfusion defect disappears. Based on this finding the study was interpreted as normal with breast attenuation on NAC images.

Figure 7

High-risk MPS in 63-years-old referred for cardiac risk stratification before vascular surgery. The stress images show extensive ischemia in the anterior (white arrows), lateral wall (red arrow) and inferior wall (yellow arrow). The gated images (not shown) demonstrate dilated LV with severe LV dysfunction, LV EF 24%.