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Publisher’s Note: Continued Publication of Tomography by MDPI
Open AccessArticle

Respiratory Motion Mitigation and Repeatability of Two Diffusion-Weighted MRI Methods Applied to a Murine Model of Spontaneous Pancreatic Cancer

1
Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
2
Department of Biostatistics, Epidemiology and Informatics, University of Pennsylvania, Philadelphia, PA 19104, USA
3
Pancreatic Cancer Research Center, University of Pennsylvania, Philadelphia, PA 19104, USA
4
Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA 19104, USA
*
Author to whom correspondence should be addressed.
Academic Editor: Brian D. Ross
Tomography 2021, 7(1), 66-79; https://doi.org/10.3390/tomography7010007
Received: 12 December 2020 / Accepted: 2 February 2021 / Published: 20 February 2021
Respiratory motion and increased susceptibility effects at high magnetic fields pose challenges for quantitative diffusion-weighted MRI (DWI) of a mouse abdomen on preclinical MRI systems. We demonstrate the first application of radial k-space-sampled (RAD) DWI of a mouse abdomen using a genetically engineered mouse model of pancreatic ductal adenocarcinoma (PDAC) on a 4.7 T preclinical scanner equipped with moderate gradient capability. RAD DWI was compared with the echo-planar imaging (EPI)-based DWI method with similar voxel volumes and acquisition times over a wide range of b-values (0.64, 535, 1071, 1478, and 2141 mm2/s). The repeatability metrics are assessed in a rigorous test–retest study (n = 10 for each DWI protocol). The four-shot EPI DWI protocol leads to higher signal-to-noise ratio (SNR) in diffusion-weighted images with persisting ghosting artifacts, whereas the RAD DWI protocol produces relatively artifact-free images over all b-values examined. Despite different degrees of motion mitigation, both RAD DWI and EPI DWI allow parametric maps of apparent diffusion coefficients (ADC) to be produced, and the ADC of the PDAC tumor estimated by the two methods are 1.3 ± 0.24 and 1.5 ± 0.28 × 10−3 mm2/s, respectively (p = 0.075, n = 10), and those of a water phantom are 3.2 ± 0.29 and 2.8 ± 0.15 × 10−3 mm2/s, respectively (p = 0.001, n = 10). Bland-Altman plots and probability density function reveal good repeatability for both protocols, whose repeatability metrics do not differ significantly. In conclusion, RAD DWI enables a more effective respiratory motion mitigation but lower SNR, while the performance of EPI DWI is expected to improve with more advanced gradient hardware. View Full-Text
Keywords: radial k-space sampling; diffusion-weighted MRI; apparent diffusion coefficient; repeatability; pancreatic ductal adenocarcinoma radial k-space sampling; diffusion-weighted MRI; apparent diffusion coefficient; repeatability; pancreatic ductal adenocarcinoma
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MDPI and ACS Style

Cao, J.; Song, H.K.; Yang, H.; Castillo, V.; Chen, J.; Clendenin, C.; Rosen, M.; Zhou, R.; Pickup, S. Respiratory Motion Mitigation and Repeatability of Two Diffusion-Weighted MRI Methods Applied to a Murine Model of Spontaneous Pancreatic Cancer. Tomography 2021, 7, 66-79. https://doi.org/10.3390/tomography7010007

AMA Style

Cao J, Song HK, Yang H, Castillo V, Chen J, Clendenin C, Rosen M, Zhou R, Pickup S. Respiratory Motion Mitigation and Repeatability of Two Diffusion-Weighted MRI Methods Applied to a Murine Model of Spontaneous Pancreatic Cancer. Tomography. 2021; 7(1):66-79. https://doi.org/10.3390/tomography7010007

Chicago/Turabian Style

Cao, Jianbo; Song, Hee K.; Yang, Hanwen; Castillo, Victor; Chen, Jinbo; Clendenin, Cynthia; Rosen, Mark; Zhou, Rong; Pickup, Stephen. 2021. "Respiratory Motion Mitigation and Repeatability of Two Diffusion-Weighted MRI Methods Applied to a Murine Model of Spontaneous Pancreatic Cancer" Tomography 7, no. 1: 66-79. https://doi.org/10.3390/tomography7010007

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