Diffusion-weighted Imaging Voxelwise-matched Analyses of Lung Cancer at 3.0-T PET/MRI: Reverse Phase Encoding Approach for Echo-planar Imaging Distortion Correction

Background PET/MRI has drawn increasing interest in thoracic oncology due to the simultaneous acquisition of PET and MRI data. Geometric distortions related to diffusion-weighted imaging (DWI) limit the evaluation of voxelwise multimodal analyses. Purpose To assess the effectiveness of reverse phase...

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Bibliographic Details
Published in:	Radiology Vol. 295; no. 3; pp. 692 - 700
Main Authors:	Besson, Florent L, Fernandez, Brice, Faure, Sylvain, Mercier, Olaf, Seferian, Andrei, Blanchet, Élise, Mignard, Xavier, Chetouani, Ahmed, Bulifon, Sophie, Mussot, Sacha, Parent, Florence, Bouderraoui, Fahd, Montani, David, Mitilian, Delphine, Fadel, Elie, Ghigna-Bellinzoni, Maria-Rosa, Cherkaoui, Hamza, Comtat, Claude, Lebon, Vincent, Durand, Emmanuel
Format:	Journal Article
Language:	English
Published:	United States Radiological Society of North America 01-06-2020
Subjects:	Human health and pathology Life Sciences
Online Access:	Get full text
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Summary:	Background PET/MRI has drawn increasing interest in thoracic oncology due to the simultaneous acquisition of PET and MRI data. Geometric distortions related to diffusion-weighted imaging (DWI) limit the evaluation of voxelwise multimodal analyses. Purpose To assess the effectiveness of reverse phase encoding in correcting DWI geometric distortion for multimodal PET/MRI voxelwise lung tumor analyses. Materials and Methods In this prospective study, reverse phase encoding method was implemented with 3.0-T PET/MRI to correct geometric distortions related to DWI. The method was validated in dedicated phantom and then applied to 12 consecutive patients (mean age, 66 years ± 13 [standard deviation]; 10 men) suspected of having lung cancer who underwent fluorodeoxyglucose PET/MRI between October 2018 and April 2019. The effects on DWI-related image matching and apparent diffusion coefficient (ADC) regional map computation were assessed. Consequences on multimodal PET/MRI voxelwise lung tumor analyses were evaluated. Spearman correlation coefficients ( ) between the standardized uptake value (SUV) and ADC data corrected for distortion were computed from optimal realigned DWI PET data, along with bootstrap confidence intervals. Results Phantom results showed that in highly distorted areas, correcting the distortion significantly reduced the mean error against the ground truth (-25% ± 10.6 to -18.4% ± 12.6; < .001) and the number of voxels with more than 20% error (from 85.3% to 31.4%). In the 12 patients, the coregistration of multimodal PET/MRI tumor data was improved by using the reverse phase encoding method (0.4%-44%). In all tumors, voxelwise correlations ( ) between ADC and SUV revealed null or weak monotonic relationships (mean of 0.016 ± 0.24 with none above 0.5). Conclusion Reverse phase encoding is a simple-to-implement method for improved diffusion-weighted multimodal PET/MRI voxelwise-matched analyses in lung cancer. © RSNA, 2020 See also the editorial by Colletti in this issue.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0033-8419 1527-1315
DOI:	10.1148/radiol.2020192013