Task-based optimization of flip angle for texture analysis in MRI

Jonathan F. Brand, Lars R. Furenlid, Maria I. Altbach, Jean Phillippe Galons, Achyut Bhattacharyya, Puneet Sharma, Tulshi Bhattacharyya, Ali Bilgin, Diego R. Martin

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Chronic liver disease is a worldwide health problem, and hepatic fibrosis (HF) is one of the hallmarks of the disease. The current reference standard for diagnosing HF is biopsy followed by pathologist examination, however this is limited by sampling error and carries risk of complications. Pathology diagnosis of HF is based on textural change in the liver as a lobular collagen network that develops within portal triads. The scale of collagen lobules is characteristically on order of 1-5 mm, which approximates the resolution limit of in vivo gadolinium-enhanced magnetic resonance imaging in the delayed phase. We have shown that MRI of formalin fixed human ex vivo liver samples mimic the textural contrast of in vivo Gd-MRI and can be used as MRI phantoms. We have developed local texture analysis that is applied to phantom images, and the results are used to train model observers. The performance of the observer is assessed with the area-under-the-receiveroperator- characteristic curve (AUROC) as the figure of merit. To optimize the MRI pulse sequence, phantoms are scanned with multiple times at a range of flip angles. The flip angle that associated with the highest AUROC is chosen as optimal based on the task of detecting HF.

Original languageEnglish (US)
Title of host publicationMedical Imaging 2016
Subtitle of host publicationImage Perception, Observer Performance, and Technology Assessment
EditorsCraig K. Abbey, Matthew A. Kupinski
ISBN (Electronic)9781510600225
StatePublished - 2016
EventMedical Imaging 2016: Image Perception, Observer Performance, and Technology Assessment - San Diego, United States
Duration: Mar 2 2016Mar 3 2016

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
ISSN (Print)1605-7422


ConferenceMedical Imaging 2016: Image Perception, Observer Performance, and Technology Assessment
Country/TerritoryUnited States
CitySan Diego


  • Hepatic fibrosis
  • Hotelling observer
  • Liver
  • MRI
  • Magnetic resonance imaging
  • Optimization
  • Texture analysis

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Biomaterials
  • Radiology Nuclear Medicine and imaging


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