Mapping prostatic microscopic anisotropy using linear and spherical b-tensor encoding : A preliminary study
(2021) In Magnetic Resonance in Medicine 86(4). p.2025-2033- Abstract
Purpose: Tensor-valued diffusion encoding provides more specific information than conventional diffusion-weighted imaging (DWI), but has mainly been applied in neuroimaging studies. This study aimed to assess its potential for the imaging of prostate cancer (PCa). Methods: Seventeen patients with histologically proven PCa were enrolled. DWI of the prostate was performed with linear and spherical tensor encoding using a maximal b-value of 1.5 ms/µm2 and a voxel size of 3 × 3 × 4 mm3. The gamma-distribution model was used to estimate the mean diffusivity (MD), the isotropic kurtosis (MKI), and the anisotropic kurtosis (MKA). Regions of interest were placed in MR-defined cancerous tissues, as... (More)
Purpose: Tensor-valued diffusion encoding provides more specific information than conventional diffusion-weighted imaging (DWI), but has mainly been applied in neuroimaging studies. This study aimed to assess its potential for the imaging of prostate cancer (PCa). Methods: Seventeen patients with histologically proven PCa were enrolled. DWI of the prostate was performed with linear and spherical tensor encoding using a maximal b-value of 1.5 ms/µm2 and a voxel size of 3 × 3 × 4 mm3. The gamma-distribution model was used to estimate the mean diffusivity (MD), the isotropic kurtosis (MKI), and the anisotropic kurtosis (MKA). Regions of interest were placed in MR-defined cancerous tissues, as well as in apparently healthy tissues in the peripheral and transitional zones (PZs and TZs). Results: DWI with linear and spherical encoding yielded different image contrasts at high b-values, which enabled the estimation of MKA and MKI. Compared with healthy tissue (PZs and TZs combined) the cancers displayed a significantly lower MD (P <.05), higher MKI (P < 10−5), and lower MKA (P <.05). Compared with the TZ, tissue in the PZ showed lower MD (P < 10−3) and higher MKA (P < 10−3). No significant differences were found between cancers of different Gleason scores, possibly because of the limited sample size. Conclusion: Tensor-valued diffusion encoding enabled mapping of MKA and MKI in the prostate. The elevated MKI in PCa compared with normal tissues suggests an elevated heterogeneity in the cancers. Increased in-plane resolution could improve tumor delineation in future studies.
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- author
- Nilsson, Markus LU ; Eklund, Greta LU ; Szczepankiewicz, Filip LU ; Skorpil, Mikael ; Bryskhe, Karin LU ; Westin, Carl Fredrik ; Lindh, Claes ; Blomqvist, Lennart and Jäderling, Fredrik
- organization
- publishing date
- 2021
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- diffusion-weighted imaging, heterogeneity, microscopic anisotropy, prostate cancer, tensor-valued diffusion encoding
- in
- Magnetic Resonance in Medicine
- volume
- 86
- issue
- 4
- pages
- 9 pages
- publisher
- John Wiley & Sons Inc.
- external identifiers
-
- pmid:34056750
- scopus:85107007467
- ISSN
- 0740-3194
- DOI
- 10.1002/mrm.28856
- language
- English
- LU publication?
- yes
- id
- b35aed0c-d2d4-4709-85a7-3d95c3545fc4
- date added to LUP
- 2021-12-09 15:40:35
- date last changed
- 2024-08-11 03:11:36
@article{b35aed0c-d2d4-4709-85a7-3d95c3545fc4, abstract = {{<p>Purpose: Tensor-valued diffusion encoding provides more specific information than conventional diffusion-weighted imaging (DWI), but has mainly been applied in neuroimaging studies. This study aimed to assess its potential for the imaging of prostate cancer (PCa). Methods: Seventeen patients with histologically proven PCa were enrolled. DWI of the prostate was performed with linear and spherical tensor encoding using a maximal b-value of 1.5 ms/µm<sup>2</sup> and a voxel size of 3 × 3 × 4 mm<sup>3</sup>. The gamma-distribution model was used to estimate the mean diffusivity (MD), the isotropic kurtosis (MK<sub>I</sub>), and the anisotropic kurtosis (MK<sub>A</sub>). Regions of interest were placed in MR-defined cancerous tissues, as well as in apparently healthy tissues in the peripheral and transitional zones (PZs and TZs). Results: DWI with linear and spherical encoding yielded different image contrasts at high b-values, which enabled the estimation of MK<sub>A</sub> and MK<sub>I</sub>. Compared with healthy tissue (PZs and TZs combined) the cancers displayed a significantly lower MD (P <.05), higher MK<sub>I</sub> (P < 10<sup>−5</sup>), and lower MK<sub>A</sub> (P <.05). Compared with the TZ, tissue in the PZ showed lower MD (P < 10<sup>−3</sup>) and higher MK<sub>A</sub> (P < 10<sup>−3</sup>). No significant differences were found between cancers of different Gleason scores, possibly because of the limited sample size. Conclusion: Tensor-valued diffusion encoding enabled mapping of MK<sub>A</sub> and MK<sub>I</sub> in the prostate. The elevated MK<sub>I</sub> in PCa compared with normal tissues suggests an elevated heterogeneity in the cancers. Increased in-plane resolution could improve tumor delineation in future studies.</p>}}, author = {{Nilsson, Markus and Eklund, Greta and Szczepankiewicz, Filip and Skorpil, Mikael and Bryskhe, Karin and Westin, Carl Fredrik and Lindh, Claes and Blomqvist, Lennart and Jäderling, Fredrik}}, issn = {{0740-3194}}, keywords = {{diffusion-weighted imaging; heterogeneity; microscopic anisotropy; prostate cancer; tensor-valued diffusion encoding}}, language = {{eng}}, number = {{4}}, pages = {{2025--2033}}, publisher = {{John Wiley & Sons Inc.}}, series = {{Magnetic Resonance in Medicine}}, title = {{Mapping prostatic microscopic anisotropy using linear and spherical b-tensor encoding : A preliminary study}}, url = {{http://dx.doi.org/10.1002/mrm.28856}}, doi = {{10.1002/mrm.28856}}, volume = {{86}}, year = {{2021}}, }