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Zero TE MR bone imaging in the head
Author(s) -
Wiesinger Florian,
Sacolick Laura I.,
Menini Anne,
Kaushik Sandeep S.,
Ahn Sangtae,
VeitHaibach Patrick,
Delso Gaspar,
Shanbhag Dattesh D.
Publication year - 2016
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.26094
Subject(s) - hounsfield scale , soft tissue , segmentation , histogram , materials science , nuclear medicine , cortical bone , physics , nuclear magnetic resonance , computer science , artificial intelligence , medicine , radiology , image (mathematics) , computed tomography , anatomy
Purpose To investigate proton density (PD)‐weighted zero TE (ZT) imaging for morphological depiction and segmentation of cranial bone structures. Methods A rotating ultra‐fast imaging sequence (RUFIS) type ZT pulse sequence was developed and optimized for 1) efficient capture of short T 2 bone signals and 2) flat PD response for soft‐tissues. An inverse logarithmic image scaling (i.e., −log(image)) was used to highlight bone and differentiate it from surrounding soft‐tissue and air. Furthermore, a histogram‐based bias‐correction method was developed for subsequent threshold‐based air, soft‐tissue, and bone segmentation. Results PD‐weighted ZT imaging in combination with an inverse logarithmic scaling was found to provide excellent depiction of cranial bone structures. In combination with bias correction, also excellent segmentation results were achieved. A two‐dimensional histogram analysis demonstrates a strong, approximately linear correlation between inverse log‐scaled ZT and low‐dose CT for Hounsfield units (HU) between −300 HU and 1,500 HU (corresponding to soft‐tissue and bone). Conclusions PD‐weighted ZT imaging provides robust and efficient depiction of bone structures in the head, with an excellent contrast between air, soft‐tissue, and bone. Besides structural bone imaging, the presented method is expected to be of relevance for attenuation correction in positron emission tomography (PET)/MR and MR‐based radiation therapy planning. Magn Reson Med 75:107–114, 2016. © 2015 Wiley Periodicals, Inc.