Cardiac Displacement During ¹³N-Ammonia Myocardial Perfusion PET/CT: Comparison Between Adenosine- and Regadenoson-Induced Stress

Abstract

This study investigated differences in cardiac displacement during adenosine stress versus regadenoson stress in N-ammonia (NH) MP PET/CT scans. In total, 61 myocardial perfusion PET/CT scans were acquired using either adenosine ( = 30) or regadenoson ( = 31) as a stressor. For both groups, cardiac displacement during rest and stress was measured 3-dimensionally, relative to either a fixed reference frame or the previous frame, in each 1-min frame of a list-mode PET acquisition of 25 min. All stress scans were additionally evaluated for the presence of motion artifacts. Also, the tolerability of the agents and the occurrence of side effects were compared between groups. Significantly larger cardiac displacement during stress was detected in the adenosine group than in the regadenoson group, reflected by both maximal cardiac displacement ( = 0.022) and mean cardiac displacement ( = 0.001). The duration of the movement was typically shorter in the regadenoson group. Frames with cardiac displacement of at least 5 mm were observed nearly twice as frequently when adenosine was used instead of regadenoson. The displacement during regadenoson stress is of lower amplitude and shorter duration than that during adenosine stress and may therefore contribute to a lower incidence of motion artifacts on PET/CT scans.

Influence of patient motion on quantitative accuracy in cardiac 15O-water positron emission tomography

“…The choice of stress agent and protocol can impact patient body motion with a more pronounced motion seen using adenosine compared to for regadenoson. 7,8 Patient body motion is a common problem in cardiac PET studies with an occurrence of 30% to 69%, particularly during stress. 7,[9][10][11] Cardiac creep, i.e.…”

A tale of two phases: Can the worst of scans become the best of scans with motion correction?

“…We believe this may originate from changes in the patients breathing patterns during pharmacological stressing, with different patterns and magnitudes seen for different stress pharmaceuticals and infusion durations. 8,9 While the authors' conclusions suggest that motion in early frames is most important, we believe that whether motion occurs in early or late phases of the scan may simply be relative. If the reference segmentation is derived from late images, it is quite feasible to interpret that motion is in the early phase, and therefore an analysis of the differential motion (frameto-frame) would perhaps be more insightful.…”

“…The type and cause of patient motion is generally either periodic physiological sources such as respiratory motion, or more random effects such as in response to the effects of vasodilator stress agents, 8,9 or actual physical movements of the patient. Respiratory motion effects and to some extent physical movements of the patient may be automatically corrected by data-driven techniques 10 however this is likely to be particularly challenging in the case of dynamic PET using shortlived tracers.…”

“…While this methodology has been shown to provide optimal sampling for MBF calculation, 17 and would reduce inter-frame motion, it remains to be demonstrated that this would accurately capture intra-frame motion in the tissue phase. By analyzing cardiac displacement throughout the entire image process (pre and post infusion) Vleeming et al 9 have demonstrated that, while the greatest rate of change in motion occurs around the time of the stress agent and tracer infusion, significant motion does indeed occur in the later frames and hence one could postulate that adequate compensation for motion may require optimisation independent to achieving accurate MBF calculations.…”

Myocardial blood flow: Is motion correction necessary?

“…2 Cardiorespiratory motion during acquisitions is another issue for MBF examinations, where the cardiorespiratory motion might introduce a general smear of the pathologic area. [7][8][9] Related to this issue is the wear-off of the pharmaceutical agents used for stress MBF examinations, resulting in changes of the respiratory depth and frequency [10][11][12] -a problem often referred to as ''myocardial creep''. This effect causes repositioning of the heart during scans, and consequently affects the time-activity curves used for the MBF evaluations.…”