Gd-EOB enhanced MRI T1-weighted 3D-GRE with and without elevated flip angle modulation for threshold-based liver volume segmentation

Acta Radiol. 2015 Dec;56(12):1419-27. doi: 10.1177/0284185114558975. Epub 2014 Nov 18.

Abstract

Background: Despite novel software solutions, liver volume segmentation is still a time-consuming procedure and often requires further manual optimization. With the high signal intensity of the liver parenchyma in Gd-EOB enhanced magnetic resonance imaging (MRI), liver volume segmentation may be improved.

Purpose: To evaluate the practicability of threshold-based segmentation of the liver volume using Gd-EOB-enhanced MRI including a customized three-dimensional (3D) sequence.

Material and methods: A total of 20 patients examined with Gd-EOB MRI (hepatobiliary phase T1-weighted (T1W) 3D sequence [VIBE]; flip angle [FA], 10° and 30°) were enrolled in this retrospective study. The datasets were independently processed by two blinded observers (O1 and O2) in two ways: manual (man) and threshold-based (thresh; study method) segmentation of the liver each followed by an optimization step (man+opt and thresh+opt; man+opt [FA10°] served as reference method). Resulting liver volumes and segmentation times were compared. A liver conversion factor was calculated in percent, describing the non-hepatocellular fraction of the total liver volume, i.e. bile ducts and vessels.

Results: Thresh+opt (FA10°) was significantly faster compared to the reference method leading to a median volume overestimation of 4%/8% (P < 0.001). Using thresh+opt (FA30°), segmentation was even faster (P < 0.001) and even reduced median volume deviation of 0%/2% (O1/O2; both P > 0.2). The liver conversion factor was found to be 10%.

Conclusion: Threshold-based liver segmentation employing Gd-EOB-enhanced hepatobiliary phase standard T1W 3D sequence is accurate and time-saving. The performance of this approach can be further improved by increasing the FA.

Keywords: Gd-EOB; Liver MRI; flip angle; gadoxetic acid; liver segmentation; liver volume.

MeSH terms

  • Contrast Media
  • Female
  • Gadolinium DTPA*
  • Humans
  • Image Enhancement*
  • Imaging, Three-Dimensional*
  • Liver / pathology*
  • Liver Neoplasms / pathology*
  • Magnetic Resonance Imaging*
  • Male
  • Middle Aged
  • Organ Size
  • Reproducibility of Results
  • Retrospective Studies
  • Sensitivity and Specificity

Substances

  • Contrast Media
  • gadolinium ethoxybenzyl DTPA
  • Gadolinium DTPA