Model-based reconstruction framework for correction of signal pile-up and geometric distortions in prostate diffusion MRI.
Magn Reson Med
; 81(3): 1979-1992, 2019 03.
Article
em En
| MEDLINE
| ID: mdl-30393895
ABSTRACT
PURPOSE:
Prostate diffusion-weighted MRI scans can suffer from geometric distortions, signal pileup, and signal dropout attributed to differences in tissue susceptibility values at the interface between the prostate and rectal air. The aim of this work is to present and validate a novel model based reconstruction method that can correct for these distortions.METHODS:
In regions of severe signal pileup, standard techniques for distortion correction have difficulty recovering the underlying true signal. Furthermore, because of drifts and inaccuracies in the determination of center frequency, echo planar imaging (EPI) scans can be shifted in the phase-encoding direction. In this work, using a B0 field map and a set of EPI data acquired with blip-up and blip-down phase encoding gradients, we model the distortion correction problem linking the distortion-free image to the acquired raw corrupted k-space data and solve it in a manner analogous to the sensitivity encoding method. Both a quantitative and qualitative assessment of the proposed method is performed in vivo in 10 patients.RESULTS:
Without distortion correction, mean Dice similarity scores between a reference T2W and the uncorrected EPI images were 0.64 and 0.60 for b-values of 0 and 500 s/mm2 , respectively. Compared to the Topup (distortion correction method commonly used for neuro imaging), the proposed method achieved Dice scores (0.87 and 0.85 versus 0.82 and 0.80) and better qualitative results in patients where signal pileup was present because of high rectal gas residue.CONCLUSION:
Model-based reconstruction can be used for distortion correction in prostate diffusion MRI.Palavras-chave
Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Próstata
/
Neoplasias da Próstata
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Processamento de Imagem Assistida por Computador
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Imagem Ecoplanar
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Imagem de Difusão por Ressonância Magnética
Tipo de estudo:
Prognostic_studies
/
Qualitative_research
Limite:
Aged
/
Humans
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Male
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Middle aged
Idioma:
En
Ano de publicação:
2019
Tipo de documento:
Article