Related Experiment Video
Updated: Dec 14, 2025
Magnetic Resonance Derived Myocardial Strain Assessment Using Feature Tracking
Published on: February 12, 2011
Myocardial creep-induced misalignment artifacts in PET/MR myocardial perfusion imaging
Elia von Felten1, Georgios Benetos1, Dimitri Patriki1
1Department of Nuclear Medicine, Cardiac Imaging, University Hospital Zurich, University of Zurich, Ramistrasse 100, CH-8091, Zurich, Switzerland.
Purpose:
Misalignment between positron emission tomography (PET) datasets and attenuation correction (AC) maps is a potential source of artifacts in myocardial perfusion imaging (MPI). We assessed the impact of adenosine on the alignment of AC maps derived from magnetic resonance (MR) and PET datasets during MPI on a hybrid PET/MR scanner.
Methods:
Twenty-eight volunteers underwent adenosine stress and rest 13N-ammonia MPI on a PET/MR. We acquired Dixon sequences for the creation of MRAC maps. After reconstruction of the original non-shifted PET images, we examined MRAC and PET datasets for cardiac spatial misalignment and, if necessary, reconstructed a second set of shifted PET images after manually adjusting co-registration. Summed rest, stress, and difference scores (SRS, SSS, and SDS) were compared between shifted and non-shifted PET images. Additionally, we measured the amount of cranial movement of the heart (i.e., myocardial creep) after termination of adenosine infusion.
Results:
Realignment was necessary for 25 (89.3%) stress and 12 (42.9%) rest PET datasets. Median SRS, SSS, and SDS of the non-shifted images were 6 (IQR = 4-7), 12 (IQR = 7-18), and 8 (IQR = 2-11), respectively, and of the shifted images 2 (IQR = 1-6), 4 (IQR = 7-18), and 1 (IQR = 0-2), respectively. All three scores were significantly higher in non-shifted versus shifted images (all p < 0.05). The difference in SDS correlated moderately but significantly with the amount of myocardial creep (r = 0.541, p = 0.005).
Conclusion:
Misalignment of MRAC and PET datasets commonly occurs during adenosine stress MPI on a hybrid PET/MR device, potentially leading to an increase in false-positive findings. Our results suggest that myocardial creep may substantially account for this and prompt for a careful review and correction of PET/MRAC data.
Insights
Misalignment between PET and MR attenuation correction maps is common in hybrid PET/MR myocardial perfusion imaging. Myocardial creep during adenosine stress significantly impacts image alignment, potentially causing false positives.
Area of Science:
- Cardiovascular Imaging
- Medical Physics
- Radiology
Background:
- Positron emission tomography (PET) and magnetic resonance (MR) imaging are advanced modalities for myocardial perfusion imaging (MPI).
- Hybrid PET/MR scanners offer integrated data acquisition but face challenges with spatial alignment between PET and MR-derived attenuation correction (AC) maps.
- Misalignment can introduce artifacts, potentially leading to misinterpretation of myocardial perfusion.
Purpose of the Study:
- To assess the impact of adenosine on the spatial alignment of MR-derived AC maps and PET datasets during MPI.
- To evaluate the frequency of misalignment and its effect on quantitative perfusion metrics.
- To investigate the role of myocardial creep in causing misalignment during adenosine stress MPI.
Main Methods:
- Twenty-eight volunteers underwent adenosine stress and rest 13N-ammonia MPI on a hybrid PET/MR scanner.
- MRAC maps were generated using Dixon sequences; PET images were reconstructed with and without manual co-registration adjustments.
- Summed rest, stress, and difference scores (SRS, SSS, SDS) were compared between shifted and non-shifted PET images; myocardial creep was quantified.
Main Results:
- Realignment was necessary for 89.3% of stress and 42.9% of rest PET datasets.
- Non-shifted images showed significantly higher SRS, SSS, and SDS compared to shifted images (p < 0.05).
- The difference in SDS correlated significantly with myocardial creep (r=0.541, p=0.005).
Conclusions:
- Misalignment between MRAC and PET datasets is frequent during adenosine stress MPI on hybrid PET/MR devices.
- Myocardial creep appears to be a significant contributor to this misalignment.
- Careful review and correction of PET/MRAC data are recommended to avoid false-positive findings in MPI.
