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Intensity-based dual model method for generation of synthetic CT images from standard T2-weighted MR images - Generalized technique for four different MR scanners

Koivula, Lauri; Kapanen, Mika; Seppälä, Tiina; Collan, Juhani; Dowling, Jason A.; Greer, Peter B.; Gustafsson, Christian LU ; Gunnlaugsson, Adalsteinn LU ; Olsson, Lars E. LU and Wee, Leonard, et al. (2017) In Radiotherapy and Oncology 125(3). p.411-419
Abstract

Background and purpose: Recent studies have shown that it is possible to conduct entire radiotherapy treatment planning (RTP) workflow using only MR images. This study aims to develop a generalized intensity-based method to generate synthetic CT (sCT) images from standard T2-weighted (T2w) MR images of the pelvis. Materials and methods: This study developed a generalized dual model HU conversion method to convert standard T2w MR image intensity values to synthetic HU values, separately inside and outside of atlas-segmented bone volume contour. The method was developed and evaluated with 20 and 35 prostate cancer patients, respectively. MR images with scanning sequences in clinical use were acquired with four... (More)

Background and purpose: Recent studies have shown that it is possible to conduct entire radiotherapy treatment planning (RTP) workflow using only MR images. This study aims to develop a generalized intensity-based method to generate synthetic CT (sCT) images from standard T2-weighted (T2w) MR images of the pelvis. Materials and methods: This study developed a generalized dual model HU conversion method to convert standard T2w MR image intensity values to synthetic HU values, separately inside and outside of atlas-segmented bone volume contour. The method was developed and evaluated with 20 and 35 prostate cancer patients, respectively. MR images with scanning sequences in clinical use were acquired with four different MR scanners of three vendors. Results: For the generated synthetic CT (sCT) images of the 35 prostate patients, the mean (and maximal) HU differences in soft and bony tissue volumes were 16±6HUs (34HUs) and -46±56HUs (181HUs), respectively, against the true CT images. The average of the PTV mean dose difference in sCTs compared to those in true CTs was -0.6±0.4% (-1.3%). Conclusions: The study provides a generalized method for sCT creation from standard T2w images of the pelvis. The method produced clinically acceptable dose calculation results for all the included scanners and MR sequences.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
MRI-only, Radiation therapy, Synthetic CT images
in
Radiotherapy and Oncology
volume
125
issue
3
pages
411 - 419
publisher
Elsevier
external identifiers
  • scopus:85032741396
ISSN
0167-8140
DOI
10.1016/j.radonc.2017.10.011
language
English
LU publication?
yes
id
42cc0eec-2ae1-4c14-bd1a-8e8fb70100ed
date added to LUP
2017-12-01 13:09:22
date last changed
2018-01-07 12:27:09
@article{42cc0eec-2ae1-4c14-bd1a-8e8fb70100ed,
  abstract     = {<p>Background and purpose: Recent studies have shown that it is possible to conduct entire radiotherapy treatment planning (RTP) workflow using only MR images. This study aims to develop a generalized intensity-based method to generate synthetic CT (sCT) images from standard T2-weighted (T2<sub>w</sub>) MR images of the pelvis. Materials and methods: This study developed a generalized dual model HU conversion method to convert standard T2<sub>w</sub> MR image intensity values to synthetic HU values, separately inside and outside of atlas-segmented bone volume contour. The method was developed and evaluated with 20 and 35 prostate cancer patients, respectively. MR images with scanning sequences in clinical use were acquired with four different MR scanners of three vendors. Results: For the generated synthetic CT (sCT) images of the 35 prostate patients, the mean (and maximal) HU differences in soft and bony tissue volumes were 16±6HUs (34HUs) and -46±56HUs (181HUs), respectively, against the true CT images. The average of the PTV mean dose difference in sCTs compared to those in true CTs was -0.6±0.4% (-1.3%). Conclusions: The study provides a generalized method for sCT creation from standard T2<sub>w</sub> images of the pelvis. The method produced clinically acceptable dose calculation results for all the included scanners and MR sequences.</p>},
  author       = {Koivula, Lauri and Kapanen, Mika and Seppälä, Tiina and Collan, Juhani and Dowling, Jason A. and Greer, Peter B. and Gustafsson, Christian and Gunnlaugsson, Adalsteinn and Olsson, Lars E. and Wee, Leonard and Korhonen, Juha},
  issn         = {0167-8140},
  keyword      = {MRI-only,Radiation therapy,Synthetic CT images},
  language     = {eng},
  month        = {10},
  number       = {3},
  pages        = {411--419},
  publisher    = {Elsevier},
  series       = {Radiotherapy and Oncology},
  title        = {Intensity-based dual model method for generation of synthetic CT images from standard T2-weighted MR images - Generalized technique for four different MR scanners},
  url          = {http://dx.doi.org/10.1016/j.radonc.2017.10.011},
  volume       = {125},
  year         = {2017},
}