Flow-compensated diffusion encoding in MRI for improved liver metastasis detection

PLoS One. 2022 May 26;17(5):e0268843. doi: 10.1371/journal.pone.0268843. eCollection 2022.

Abstract

Magnetic resonance (MR) diffusion-weighted imaging (DWI) is often used to detect focal liver lesions (FLLs), though DWI image quality can be limited in the left liver lobe owing to the pulsatile motion of the nearby heart. Flow-compensated (FloCo) diffusion encoding has been shown to reduce this pulsation artifact. The purpose of this prospective study was to intra-individually compare DWI of the liver acquired with conventional monopolar and FloCo diffusion encoding for assessing metastatic FLLs in non-cirrhotic patients. Forty patients with known or suspected multiple metastatic FLLs were included and measured at 1.5 T field strength with a conventional (monopolar) and a FloCo diffusion encoding EPI sequence (single refocused; b-values, 50 and 800 s/mm2). Two board-certified radiologists analyzed the DWI images independently. They issued Likert-scale ratings (1 = worst, 5 = best) for pulsation artifact severity and counted the difference of lesions visible at b = 800 s/mm² separately for small and large FLLs (i.e., < 1 cm or > 1 cm) and separately for left and right liver lobe. Differences between the two diffusion encodings were assessed with the Wilcoxon signed-rank test. Both readers found a reduction in pulsation artifact in the liver with FloCo encoding (p < 0.001 for both liver lobes). More small lesions were detected with FloCo diffusion encoding in both liver lobes (left lobe: six and seven additional lesions by readers 1 and 2, respectively; right lobe: five and seven additional lesions for readers 1 and 2, respectively). Both readers found one additional large lesion in the left liver lobe. Thus, flow-compensated diffusion encoding appears more effective than monopolar diffusion encoding for the detection of liver metastases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Diffusion Magnetic Resonance Imaging / methods
  • Humans
  • Liver / diagnostic imaging
  • Liver / pathology
  • Liver Neoplasms* / diagnostic imaging
  • Liver Neoplasms* / pathology
  • Magnetic Resonance Imaging
  • Prospective Studies
  • Reproducibility of Results
  • Sensitivity and Specificity

Grants and funding

Funded study: Funding by the Deutsche Forschungsgemeinschaft is gratefully acknowledged (F.L.: DFG LA 2804/12-1, DFG LA 2804/15-1; M.S.: DFG SA 4141/1-1; https://www.dfg.de/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.