Overestimation of the Apparent Diffusion Coefficient in Diffusion-Weighted Imaging Due to Residual Fat Signal and Out-of-Phase Conditions

Dhanani M, Skwierawska D, Kuder TA, Ohlmeyer S, Uder M, Bickelhaupt S, Laun FB (2026)

Publication Type: Journal article

Publication year: 2026

Journal

Book Volume: 12

Article Number: 11

Journal Issue: 1

DOI: 10.3390/tomography12010011

Abstract

Background/Objectives: Diffusion-weighted imaging (DWI) is a magnetic resonance technique used to map the apparent diffusion coefficient ((Formula presented.)) of water in human tissue. (Formula presented.) assessment plays a central role in clinical diagnostics, as malignant tissues typically exhibit reduced water mobility and, thus, lower (Formula presented.) values. Accurately measuring the (Formula presented.) requires effective fat suppression to prevent contamination from the residual fat signal, which is commonly believed to cause (Formula presented.) underestimation. This study aimed to demonstrate that (Formula presented.) overestimation may occur as well. Methods: Our theoretical analysis shows that out-of-phase conditions between fat and water signals lead to (Formula presented.) overestimations. We performed demonstration experiments on fat–water phantoms and the breasts of 10 healthy female volunteers. In particular, we considered three out-of-phase conditions: First and second, short-time inversion recovery (STIR) fat suppression with incorrect inversion time and incorrect flip angle, respectively. Third, phase differences due to spectral fat saturation. The (Formula presented.) values were assessed in regions of interest (ROIs) that included both water and residual fat signals. Results: In the phantoms and the volunteer data, ROIs containing both fat and water signals consistently exhibited lower (Formula presented.) values under in-phase conditions and higher (Formula presented.) values under out-of-phase conditions. Conclusions: We demonstrated that out-of-phase conditions can result in (Formula presented.) overestimation in the presence of residual fat signals, potentially resulting in false-negative classifications where malignant lesions are misinterpreted as benign due to an elevated (Formula presented.). Out-of-phase fat and water signals might also reduce lesion conspicuity in high b-value images, potentially masking clinically relevant findings.

Authors with CRIS profile

Involved external institutions

Deutsches Krebsforschungszentrum (DKFZ) Germany (DE)

How to cite

APA:

Dhanani, M., Skwierawska, D., Kuder, T.A., Ohlmeyer, S., Uder, M., Bickelhaupt, S., & Laun, F.B. (2026). Overestimation of the Apparent Diffusion Coefficient in Diffusion-Weighted Imaging Due to Residual Fat Signal and Out-of-Phase Conditions. Tomography, 12(1). https://doi.org/10.3390/tomography12010011

MLA:

Dhanani, Maher, et al. "Overestimation of the Apparent Diffusion Coefficient in Diffusion-Weighted Imaging Due to Residual Fat Signal and Out-of-Phase Conditions." Tomography 12.1 (2026).

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