Background: Single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is routinely performed with patients' arms positioned above their heads to avoid potential attenuation artifact and reduced image quality. Currently no data are available to support the use of this practice using 99mTc SPECT MPI:
Methods and results: Forty-one patients referred for routine rest/stress MPI were imaged using the standard protocol with arms positioned above their heads and again with their arms at their sides. The patients were injected with 10 to 45 mCi (370 to 1665 MBq) of 99mTc-labeled sestamibi (99mTc-sestamibi), and SPECT images were acquired 30 to 90 minutes later. Thirty patients were imaged on an ADAC Vertex dual-head camera and 11 patients on an ADAC Cirrus single-head camera. Images were interpreted by 3 nuclear cardiologists without knowledge of patient identity, arm position, or camera type using a 17-segment scoring model. No significant differences were noted in the percentage of abnormal study results, reversibility extent, or location of MPI defects between the 2 arm positions in the same patients. Image quality was also similar.
Conclusion: Arm positioning does not influence the interpretation of 99mTc-sestamibi SPECT myocardial perfusion imaging with regard to image quality or defect location and extent.