Evaluating two respiratory correction methods for abdominal PET/MRI imaging

Weiwei Ruan1,2, Fang Liu1,2, Xun Sun1,2

  • 1Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1277 Jiefang Ave, Wuhan, 430022, China.

EJNMMI Physics
|January 31, 2022
PubMed
Abstract

Insights

Multi-bin respiratory gating significantly improves abdominal PET/MRI scans by reducing motion blur and increasing lesion Standard Uptake Values (SUVs). This method is more effective than end-expiratory gating, though increased noise in gated images impacts SUVmax.

Area of Science:

  • Medical Imaging
  • Nuclear Medicine
  • Radiology

Background:

  • Abdominal PET/MRI scans require respiratory motion correction due to longer acquisition times compared to PET/CT.
  • Standard Uptake Values (SUVs) in lesions can be affected by respiratory motion.
  • Evaluating respiratory motion correction methods is crucial for accurate abdominal PET/MRI interpretation.

Purpose of the Study:

  • To compare the effectiveness of two respiratory correction methods (end-expiratory gating and multi-bin gating) for abdominal PET/MRI.
  • To analyze the impact of respiratory motion correction on Standard Uptake Values (SUVs) in abdominal lesions.
  • To evaluate image quality parameters including SUVmax, SUVmean, and signal-to-noise ratio (SNR).

Main Methods:

  • 17 patients with abdominal lesions underwent PET/MRI scans after PET/CT.
  • PET images were reconstructed using end-expiratory gating and multi-bin gating.
  • Full data and partial data (first 3 min 20 s) without gating were reconstructed for comparison. SUVmax, SUVmean, background SUVmean, SD, and SNR were calculated.

Main Results:

  • Multi-bin gating significantly reduced PET image blur and increased lesion SUVmax (11.98%) and SUVmean (13.12%) compared to no gating (p=0.00).
  • Multi-bin gating was more effective than end-expiratory gating for abdominal PET/MRI.
  • The increase in SUVmax due to motion correction was not significantly different from that caused by count loss (p=0.39).

Conclusions:

  • Multi-bin respiratory gating is a more effective method for respiratory motion correction in abdominal PET/MRI than end-expiratory gating.
  • Increased noise in gated images, resulting from discarded PET data, contributes to the rise in SUVmax.
  • Respiratory motion correction is necessary for accurate abdominal PET/MRI, with multi-bin gating showing superior performance.