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Prospective comparison of longitudinal change in hepatic proton density fat fraction (PDFF) estimated by magnitude-based MRI (MRI-M) and complex-based MRI (MRI-C)

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ARTICLE DOWNLOAD

Prospective comparison of longitudinal change in hepatic proton density fat fraction (PDFF) estimated by magnitude-based MRI (MRI-M) and complex-based MRI (MRI-C)

10$

Adrija Mamidipalli, Kathryn J. Fowler, Gavin Hamilton, Tanya Wolfson, Yesenia Covarrubias, Calvin Tran, Soudabeh Fazeli, Curtis N. Wiens, Alan McMillan, Nathan S. Artz, Luke M. Funk, Guilherme M. Campos, Jacob A. Greenberg, Anthony Gamst, Michael S. Middleton, Jeffrey B. Schwimmer, Scott B. Reeder & Claude B. Sirlin 

Abstract

Purpose

To compare longitudinal hepatic proton density fat fraction (PDFF) changes estimated by magnitude- vs. complex-based chemical-shift-encoded MRI during a weight loss surgery (WLS) program in severely obese adults with biopsy-proven nonalcoholic fatty liver disease (NAFLD).

Methods

This was a secondary analysis of a prospective dual-center longitudinal study of 54 adults (44 women; mean age 52 years; range 27–70 years) with obesity, biopsy-proven NAFLD, and baseline PDFF ≥ 5%, enrolled in a WLS program. PDFF was estimated by confounder-corrected chemical-shift-encoded MRI using magnitude (MRI-M)- and complex (MRI-C)-based techniques at baseline (visit 1), after a 2- to 4-week very low–calorie diet (visit 2), and at 1, 3, and 6 months (visits 3 to 5) after surgery. At each visit, PDFF values estimated by MRI-M and MRI-C were compared by a paired t test. Rates of PDFF change estimated by MRI-M and MRI-C for visits 1 to 3, and for visits 3 to 5 were assessed by Bland-Altman analysis and intraclass correlation coefficients (ICCs).

Results

MRI-M PDFF estimates were lower by 0.5–0.7% compared with those of MRI-C at all visits (p < 0.001). There was high agreement and no difference between PDFF change rates estimated by MRI-M vs. MRI-C for visits 1 to 3 (ICC 0.983, 95% CI 0.971, 0.99; bias = − 0.13%, p = 0.22), or visits 3 to 5 (ICC 0.956, 95% CI 0.919–0.977%; bias = 0.03%, p = 0.36).

Conclusion

Although MRI-M underestimates PDFF compared with MRI-C cross-sectionally, this bias is consistent and MRI-M and MRI-C agree in estimating the rate of hepatic PDFF change longitudinally.

Key Points

• MRI-M demonstrates a significant but small and consistent bias (0.5–0.7%; p < 0.001) towards underestimation of PDFF compared with MRI-C at 3 T.

• Rates of PDFF change estimated by MRI-M and MRI-C agree closely (ICC 0.96–0.98) in adults with severe obesity and biopsy- proven NAFLD enrolled in a weight loss surgery program.

• Our findings support the use of either MRI technique (MRI-M or MRI-C) for clinical care or by individual sites or for multi-center trials that include PDFF change as an endpoint. However, since there is a bias in their measurements, the same technique should be used in any given patient for longitudinal follow-up.

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Year 2020
Language English
Format PDF
DOI 10.1007/s00330-020-06858-x