Publications

@article{Bawden2023-bk,

title = {Comparing magnetic resonance liver fat fraction measurements 

 with histology in fibrosis: the difference between proton 

 density fat fraction and tissue mass fat fraction},

author = {Stephen James Bawden and Caroline Hoad and Philip Kaye and Mary Stephenson and Grace Dolman and Martin W James and Emilie Wilkes and Andrew Austin and Indra Neil Guha and Susan Francis and Penny Gowland and Guruprasad P Aithal},

year  = {2023},

date = {2023-08-01},

journal = {MAGMA},

volume = {36},

number = {4},

pages = {553\textendash563},

publisher = {Springer Science and Business Media LLC},

abstract = {OBJECTIVE: Magnetic resonance spectroscopy (MRS) provides a 

 powerful method of measuring fat fraction. However, previous 

 studies have shown that MRS results give lower values compared 

 with visual estimates from biopsies in fibrotic livers. This 

 study investigated these discrepancies and considered whether a 

 tissue water content correction, as assessed by MRI relaxometry, 

 could provide better agreement. MATERIALS AND METHODS: 110 

 patients were scanned in a 1.5 T Philips scanner and biopsies 

 were obtained. Multiple echo MRS (30 $times$ 30 $times$ 30 mm 

 volume) was used to determine Proton Density Fat Fraction 

 (PDFF). Biopsies were assessed by visual assessment for fibrosis 

 and steatosis grading. Digital image analysis (DIA) was also 

 used to quantify fat fraction within tissue samples. T1 

 relaxation times were then used to estimate tissue water content 

 to correct PDFF for confounding factors. RESULTS: PDFF values 

 across the four visually assessed steatosis grades were 

 significantly less in the higher fibrosis group (F3-F4) compared 

 to the lower fibrosis group (F0-F2). The slope of the linear 

 regression of PDFF vs DIA fat fraction was ~ 1 in the low 

 fibrosis group and 0.77 in the high fibrosis group. Correcting 

 for water content based on T1 increased the gradient but it did 

 not reach unity. DISCUSSION: In fibrotic livers, PDFF 

 underestimated fat fraction compared to DIA methods. Values were 

 improved by applying a water content correction, but fat 

 fractions were still underestimated.},

keywords = {Fatty liver, fibrosis, liver cirrhosis, Liver diseases, Non-alcoholic fatty liver disease},

pubstate = {published},

tppubtype = {article}

}

@article{Sherry2023-op,

title = {Physical activity is inversely associated with hepatic 

 fibro-inflammation: A population-based cohort study using UK 

 Biobank data},

author = {Aron P Sherry and Scott A Willis and Thomas Yates and William Johnson and Cameron Razieh and Jack A Sargeant and Sundus Malaikah and David J Stensel and Guruprasad P Aithal and James A King},

year  = {2023},

date = {2023-01-01},

journal = {JHEP Rep.},

volume = {5},

number = {1},

pages = {100622},

publisher = {Elsevier BV},

abstract = {Background \& Aims: Physical activity (PA) is recommended in the 

 management of non-alcoholic fatty liver disease (NAFLD) given 

 its beneficial effects on liver fat and cardiometabolic risk. 

 Using data from the UK Biobank population-cohort, this study 

 examined associations between habitual PA and hepatic 

 fibro-inflammation. Methods: A total of 840 men and women aged 

 55-70 years were included in this cross-sectional study. Hepatic 

 fibro-inflammation (iron-corrected T1 [cT1]) and liver fat were 

 measured using MRI, whilst body fat was measured using 

 dual-energy X-ray absorptiometry. PA was measured using 

 accelerometry. Generalised linear models examined associations 

 between PA (light [LPA], moderate [MPA], vigorous [VPA], 

 moderate-to-vigorous [MVPA] and mean acceleration) and hepatic 

 cT1. Models were fitted for the whole sample and separately for 

 upper and lower median groups for body and liver fat. Models 

 were adjusted for sociodemographic and lifestyle variables. 

 Results: In the full sample, LPA (-0.08 ms [-0.12 to -0.03]), 

 MPA, (-0.13 ms [-0.21 to -0.05]), VPA (-1.16 ms [-1.81 to 

 -0.51]), MVPA (-0.14 ms [-0.21 to -0.06]) and mean acceleration 

 (-0.67 ms [-1.05 to-0.28]) were inversely associated with 

 hepatic cT1. With the sample split by median liver or body fat, 

 only VPA was inversely associated with hepatic cT1 in the upper 

 median groups for body (-2.68 ms [-4.24 to -1.13]) and liver fat 

 (-2.33 [-3.73 to -0.93]). PA was unrelated to hepatic cT1 in the 

 lower median groups. Conclusions: Within a population-based 

 cohort, device-measured PA is inversely associated with hepatic 

 fibro-inflammation. This relationship is strongest with VPA and 

 is greater in people with higher levels of body and liver fat. 

 Lay summary: This study has shown that people who regularly 

 perform greater amounts of physical activity have a reduced 

 level of inflammation and fibrosis in their liver. This 

 beneficial relationship is particularly strong when more intense 

 physical activity is undertaken (i.e., vigorous-intensity), and 

 is most visible in individuals with higher levels of liver fat 

 and body fat.},

keywords = {cT1, dual-energy X-ray absorptiometry, DXA, Exercise, iron-corrected T1, light   physical activity, Liver fat, LPA, milliseconds, moderate physical activity, moderate-to-vigorous physical activity, MPA, ms, MVPA, NAFLD, NASH, non-alcoholic   steatohepatitis, Non-alcoholic fatty liver disease, Non-alcoholic steatohepatitis, Obesity, PA, PDFF, physical activity, proton density fat fraction, vigorous physical activity, VPA},

pubstate = {published},

tppubtype = {article}

}