Incidence and Impact of Patient Motion in Myocardial Perfusion SPECT Imaging

Introduction: Myocardial perfusion imaging has played an important role in the evaluation and management of patients with CAD for over 20 years. Despite advances in ^99mTc based radiopharmaceuticals and multiple detector gantries, patient motion in myocardial perfusion SPECT acquisitions is still problematic and may produce artefacts which mimic the appearances of CAD. While there have been a number of significant contributions to the investigation of motion induced artefacts in myocardial perfusion imaging, the vast majority of these investigations have utilised 201TI as the radiopharmaceutical and a single detector gantry. Research Question: Is patient motion during ^99mTc based myocardial perfusion SPECT studies a significant source of potential false positive findings for CAD? Methodology: Clinical study: A prospective cross sectional study of 800 myocardial perfusion SPECT studies using ^99mTc Myoview at three Nuclear Medicine sites was used to determine the incidence, type and location of visually detectable motion. Simulation study: An experimental study was used to evaluate the effect of patient motions (identified by the clinical study) on the integrity of myocardial perfusion SPECT data using 522 motion simulations generated from a technically and diagnostically normal dataset. Results: Among the 800 individual studies analysed, 36 per cent contained visually detectable motion. 31.5 per cent of rest studies demonstrated visually detectable motion compared to 40.5 per cent for stress (p=0.004). The most common type of motion detected was "multiple bounce" which represented 47.6 per cent of motion. Left anterior oblique (LAO) and anterior were the most common specific locations in the raw data where patient motion was detected with 21.3 per cent and 17.2 per cent of motion respectively. 21.7 per cent of simulated motion demonstrated motion induced artefacts. Abrupt motion resulted in artefacts for 52.6 per cent of studies while bounce motion resulted in artefacts in 6.8 per cent of studies. The locations where motion resulted in the most studies with artefacts was at 45° (36.1 per cent) and 75° (32.4 per cent). Conclusion: This investigation demonstrated that patient motion during ^99mTc based myocardial perfusion SPECT studies is a significant source of potential false positive findings for CAD with a 7.1 per cent probability myocardial perfusion SPECT studies performed at the three Nuclear Medicine sites will contain a motion induced artefact. Fully realised, this potential results in decreased test specificity and unfavourable cost and consequence outcomes from further investigation with coronary angiography.