Development of a Computerized 4-D MRI Phantom for Liver Motion Study.

Journal Article (Journal Article)

PURPOSE: To develop a 4-dimensional computerized magnetic resonance imaging phantom with image textures extracted from real patient scans for liver motion studies. METHODS: The proposed phantom was developed based on the current version of 4-dimensional extended cardiac-torso computerized phantom and a clinical magnetic resonance scan. Initially, the extended cardiac-torso phantom was voxelized in abdominal-chest region at the end of exhalation phase. Structures/tissues were classified into 4 categories: (1) Seven key textured organs, including liver, gallbladder, spleen, stomach, heart, kidneys, and pancreas, were mapped from a clinical T1-weighted liver magnetic resonance scan using deformable registration. (2) Large textured soft tissue volumes were simulated via an iterative pattern generation method using the same magnetic resonance scan. (3) Lung and intestine structures were generated by assigning uniform intensity with proper noise modeling. (4) Bony structures were generated by assigning the magnetic resonance values. A spherical hypointensity tumor was inserted into the liver. Other respiratory phases of the 4-dimensional phantom were generated using the backward deformation vector fields exported by the extended cardiac-torso program, except that bony structures were generated separately for each phase. A weighted image filtering process was utilized to improve the overall tissue smoothness at each phase. RESULTS: Three 4-dimensional series with different motion amplitudes were generated. The developed motion phantom produced good illustrations of abdominal-chest region with anatomical structures in key organs and texture patterns in large soft tissue volumes. In a standard series, the tumor volume was measured as 13.90 ± 0.11 cm3 in a respiratory cycle and the tumor's maximum center-of-mass shift was 2.95 cm/1.84 cm on superior-inferior/anterior-posterior directions. The organ motion during the respiratory cycle was well rendered. The developed motion phantom has the flexibility of motion pattern variation, organ geometry variation, and tumor modeling variation. CONCLUSIONS: A 4-D computerized phantom was developed and could be used to produce image series with synthetic magnetic resonance textures for magnetic resonance imaging research of liver motion.

Full Text

Duke Authors

Cited Authors

  • Wang, C; Yin, F-F; Segars, WP; Chang, Z; Ren, L

Published Date

  • December 2017

Published In

Volume / Issue

  • 16 / 6

Start / End Page

  • 1051 - 1059

PubMed ID

  • 28789598

Pubmed Central ID

  • PMC5575982

Electronic International Standard Serial Number (EISSN)

  • 1533-0338

Digital Object Identifier (DOI)

  • 10.1177/1533034617723753

Language

  • eng

Conference Location

  • United States