Diffusion-weighted MRI of the lung at 3T evaluated using echo-planar-based and single-shot turbo spin-echo-based acquisition techniques for radiotherapy applications.
J Appl Clin Med Phys
; 20(1): 284-292, 2019 Jan.
Article
em En
| MEDLINE
| ID: mdl-30421496
ABSTRACT
PURPOSE:
To compare single-shot echo-planar (SS-EPI)-based and turbo spin-echo (SS-TSE)-based diffusion-weighted imaging (DWI) in Non-Small Cell Lung Cancer (NSCLC) patients and to characterize the distributions of apparent diffusion coefficient (ADC) values generated by the two techniques.METHODS:
Ten NSCLC patients were enrolled in a prospective IRB-approved study to compare and optimize DWI using EPI and TSE-based techniques for radiotherapy planning. The imaging protocol included axial T2w, EPI-based DWI and TSE-based DWI on a 3 T Philips scanner. Both EPI-based and TSE-based DWI sequences used three b values (0, 400, and 800 s/mm2 ). The acquisition times for EPI-based and TSE-based DWI were 5 and 8 min, respectively. DW-MR images were manually coregistered with axial T2w images, and tumor volume contoured on T2w images were mapped onto the DWI scans. A pixel-by-pixel fit of tumor ADC was calculated based on monoexponential signal behavior. Tumor ADC mean, standard deviation, kurtosis, and skewness were calculated and compared between EPI and TSE-based DWI. Image distortion and ADC values between the two techniques were also quantified using fieldmap analysis and a NIST traceable ice-water diffusion phantom, respectively.RESULTS:
The mean ADC for EPI and TSE-based DWI were 1.282 ± 0.42 × 10-3 and 1.211 ± 0.31 × 10-3 mm2 /s. The average skewness and kurtosis were 0.14 ± 0.4 and 2.43 ± 0.40 for DWI-EPI and -0.06 ± 0.69 and 2.89 ± 0.62 for DWI-TSE. Fieldmap analysis showed a mean distortion of 13.72 ± 8.12 mm for GTV for DWI-EPI and 0.61 ± 0.4 mm for DWI-TSE. ADC values obtained using the diffusion phantom for the two techniques were within 0.03 × 10-3 mm2 /s with respect to each other as well as the established values.CONCLUSIONS:
Diffusion-weighted turbo spin-echo shows better geometrical accuracy compared to DWI-EPI. Mean ADC values were similar with both acquisitions but the shape of the histograms was different based on the skewness and kurtosis values. The impact of differences in respiratory technique on ADC values requires further investigation.Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Processamento de Imagem Assistida por Computador
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Planejamento da Radioterapia Assistida por Computador
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Tomografia Computadorizada por Raios X
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Carcinoma Pulmonar de Células não Pequenas
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Imagens de Fantasmas
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Imagem de Difusão por Ressonância Magnética
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Neoplasias Pulmonares
Tipo de estudo:
Etiology_studies
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Observational_studies
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Risk_factors_studies
Limite:
Aged
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Aged80
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Revista:
J Appl Clin Med Phys
Assunto da revista:
BIOFISICA
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
Estados Unidos