Influence of arm position on proton density fat fraction in the liver using chemical shift-encoded magnetic resonance imaging

Watanabe, Satoshi; Shibukawa, Shuhei; Hayashi, Tatsuya; Tsuruya, Kota; Niwa, Tetsu

doi:10.1016/j.mri.2021.08.001

Cited by 1 publication

(5 citation statements)

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“…PDFF, proton density fat fraction; SD, standard deviation. improvement in B 1 + , whereas the medial anterior posterior segment showed a decrease in B 1 + (14). Therefore, elevation of the arms tended to increase the PDFF in the lumbar spine, whereas this is not necessarily the case in the liver.…”

Section: Discussionmentioning

confidence: 86%

“…The increase in PDFF observed in the elevated arm position compared with the side arm position can be attributed to the increase in the flip angle as a result of the improvement in B 1 + inhomogeneity. Conversely, this is not necessarily the case in the liver region ( 14 ). Although differences in arm positioning during MRI of the liver region have been reported to alter B 1 + distribution and, thus, affect PDFF, the variability of B 1 + associated to arm positioning depends on the segment of the liver; i.e., the PDFF may increase or decrease depending on arm position.…”

Section: Discussionmentioning

confidence: 97%

“…This is because the liver has a complex shape and is located in an area spanning from the anterior to the posterior side of the abdomen; thus, the distortion of B 1 + varies according to the liver segment. For example, the lateral segment showed an improvement in B 1 + , whereas the medial anterior posterior segment showed a decrease in B 1 + ( 14 ). Therefore, elevation of the arms tended to increase the PDFF in the lumbar spine, whereas this is not necessarily the case in the liver.…”

Section: Discussionmentioning

confidence: 99%

“…Although this drawback can be improved via the use of dual-source parallel RF excitation ( 13 ), the degree of improvement depends on the body region or body habitus. Furthermore, the spatial B 1 + variability changes the actual flip angles and can affect PDFF measurements ( 12 , 14 ). In fact, in the liver, it has been found that transmit B 1 + field changes and the PDFF on CSE-MRI can vary depending on the adopted arm position ( 14 ).…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, the spatial B 1 + variability changes the actual flip angles and can affect PDFF measurements ( 12 , 14 ). In fact, in the liver, it has been found that transmit B 1 + field changes and the PDFF on CSE-MRI can vary depending on the adopted arm position ( 14 ). This report indicates the need to consider the preparatory procedures undertaken before performing MRI.…”

Section: Introductionmentioning

confidence: 99%

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Impact of arm position on vertebral bone marrow proton density fat fraction in chemical-shift-encoded magnetic resonance imaging: a preliminary study

Hayashi¹,

Yano²,

Shibukawa³

et al. 2022

Quant Imaging Med Surg

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Arm positions employed during magnetic resonance imaging (MRI) can affect magnetic field distribution, which may result in variability in proton density fat fraction (PDFF) measurements. This study evaluated the effect of arm position on lumbar PDFF measured using chemical-shift-encoded MRI (CSE-MRI). Fifteen healthy volunteers from a single-center underwent lumbar CSE-MRI at two different arm positions (side and elevated) using a single 3T scanner. Scans were performed twice in each position.PDFFs of the L1-L5 vertebrae were independently measured by two readers, and reader measurements were compared by calculating intraclass correlation coefficients (ICC). We compared PDFF measurements from two arm positions and from two consecutive scans using the Wilcoxon test and Bland-Altman analysis. Measurements from the two readers were in high agreement [ICC =0.999; 95% confidence interval (CI), 0.998-0.999]. No significant difference was observed between PDFFs from the first and second scans of all vertebrae for each reader (all P>0.05); however, PDFF for the elevated arm position was significantly higher than that for the side arm position (37.9-44.8% vs. 37.0-43.8%; all P<0.05), except at the L2 level by reader 2. The mean differences in PDFF measurements from the first and second scans [0.1%; 95% limits of agreement (LoA), −1.8% to 1.9%] and from the side arm and elevated arm positions (0.8%; 95% LoA, −1.6% to 3.2%) were small. In conclusion, these preliminary data suggest that different arm positions during CSE-MRI can slightly affect lumbar PDFF; however, the mean absolute differences were very small.

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Section: Discussionmentioning

confidence: 86%

Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%