The review and interpretation of myocardial perfusion images are perhaps the key duty of a nuclear cardiologist. It is critical that image interpretation be performed in a systematic fashion so as to maximize the clinical value of the study and to ensure the highest-quality result of the entire procedure, providing optimal clinical information and assisting in clinical decision making. As discussed extensively in Chapter 5, the quality of the study must be reviewed and technical abnormalities be recognized. A comprehensive evaluation of all available imaging data must then be performed so as not to exclude potentially vital information.
A number of guidelines and tools have been recommended for the interpretation of myocardial perfusion studies.1–5 These policies and guidelines have been developed by experts in the field and should be used as a guide to the successful interpretation of myocardial perfusion imaging (MPI). This chapter will provide suggestions for approaches for interpretation based upon these recommendations. Of note, as single-photon emission computed tomography (SPECT) imaging is performed in the vast majority of patients undergoing radionuclide imaging, this chapter focuses on the tomographic evaluation of perfusion and function with SPECT MPI, although the methods recommended in this chapter are largely applicable to PET imaging.
The sequence of imaging should include (1) review of the raw planar images, (2) analysis of the tomographic slices, (3) interpretation of gated SPECT data, and (4) incorporation of clinical data (Table 12-1).
Table 12-1Sequence of SPECT Myocardial Image Interpretation ||Download (.pdf) Table 12-1 Sequence of SPECT Myocardial Image Interpretation
|Review raw planar images |
|Evaluate tomographic slices |
|Analyze gated SPECT data |
|Incorporate clinical data |
It is highly recommended that myocardial perfusion images be reviewed on a computer monitor as opposed to x-ray film or paper. While other media may provide useful information, the resolution of a computer monitor screen and the flexibility in adjusting a variety of parameters, including contrast, thresholds, and colors, makes this the medium that is greatly preferred. The practice of interpreting only "hard copy" images is discouraged, especially in view of the dynamic data, which is available by use of a workstation.
The patient's body habitus should be considered when interpreting images, as this information may support the artifactual nature of apparent perfusion defects. Therefore, data regarding height, weight, and gender should be provided to the interpreting physician. Additional details, such as chest and bra size and the presence of a mastectomy or breast prostheses, may also be useful.
A linear color table is recommended for the interpretation of perfusion images. While linear gray scale is preferred and is recommended by many imaging guidelines, other continuous, linear color tables such as hot body/hot iron revised may also be used effectively (Fig. 12-1). A great variety of ...