Repeatability and reproducibility comparisons of liver IVIM imaging with free‐breathing or respiratory‐triggered sequences

• Published in: NMR in biomedicine Vol. 37; no. 4; pp. e5080 - n/a
• Main Authors: Li, Xin‐Ming, Ma, Fu‐Zhao, Quan, Xian‐Yue, Zhang, Xu‐Chang, Xiao, Ben‐Heng, Wáng, Yì Xiáng J.
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.04.2024
• Subjects: Abdomen; Breathing; Coefficient of variation; Correlation coefficient; Correlation coefficients; curve fitting; Data acquisition; Diffusion Magnetic Resonance Imaging - methods; free breathing; Humans; Image acquisition; Image processing; intravoxel incoherent motion; Liver; Liver - diagnostic imaging; Magnetic Resonance Imaging; Motion; Parameters; Perfusion; Reproducibility; Reproducibility of Results; Respiration; Statistical analysis; curve fitting; free breathing; liver; intravoxel incoherent motion; reproducibility
• ISSN: 0952-3480; 1099-1492; 1099-1492
• DOI: 10.1002/nbm.5080

For liver intravoxel incoherent motion (IVIM) data acquisition, respiratory‐triggering (RT) MRI is commonly used, and there are strong motivations to shorten the scan duration. For the same scan duration, more b values or higher numbers of excitations can be allowed for free‐breathing (FB) imaging than for RT. We studied whether FB can be used to replace RT when careful IVIM image acquisition and image processing are conducted. MRI data of 22 healthy participants were acquired using a 3.0 T scanner. Diffusion imaging was based on a single‐shot spin‐echo‐type echo‐planar sequence and 16 b values of 0, 2, 4, 7, 10, 15, 20, 30, 46, 60, 72, 100, 150, 200, 400, and 600 s/mm2. Each subject attended two scan sessions with an interval of 10–20 days. For each scan session, a subject was scanned twice, first with RT and then with FB. The mean image acquisition time was 5.4 min for FB and 10.8 min for RT. IVIM parameters were calculated with bi‐exponential model segmented fitting with a threshold b value of 60 s/mm2, and fitting started from b = 2 s/mm2. There was no statistically significant difference between IVIM parameters measured with FB imaging or RT imaging. Perfusion fraction ICC (intraclass correlation coefficient) for FB imaging and RT imaging in the same scan session was 0.824. For perfusion fraction, wSD (within‐subject standard deviation), BA (Bland–Altman) difference, BA 95% limit, and ICC were 0.022, 0.0001, −0.0635~0.0637, and 0.687 for FB and 0.031, 0.0122, −0.0723~0.0967, and 0.611 for RT. For Dslow (×10−3 s/mm2), wSD, BA difference, BA 95% limit, and ICC were 0.057, 0.0268, −0.1258~0.1793, and 0.471 for FB and 0.073, −0.0078, −0.2170–0.2014, and <0.4 for RT. The Dfast coefficient of variation was 0.20 for FB imaging and 0.28 for RT imaging. All reproducibility indicators slightly favored FB imaging. For liver intravoxel incoherent motion (IVIM) data acquisition, respiratory‐triggering (RT) MRI is commonly used, and there are motivations to shorten the scan duration. We studied whether free‐breathing (FB) imaging can be used to replace RT when careful IVIM image acquisition and image processing are conducted. Good agreement was shown between FB results and RT results. Reproducibility parameters slightly favored FB imaging. Approximately half of the image data acquisition time can be saved by using FB imaging rather than RT imaging.