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) (original) (raw)
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Journal of Magnetic Resonance Imaging, 2015
PurposeTo determine the accuracy and the effect of possible subject-based confounders of magnitude-based magnetic resonance imaging (MRI) for estimating hepatic proton density fat fraction (PDFF) for different numbers of echoes in adults with known or suspected nonalcoholic fatty liver disease, using MR spectroscopy (MRS) as a reference.Materials and MethodsIn this retrospective analysis of 506 adults, hepatic PDFF was estimated by unenhanced 3.0T MRI, using right-lobe MRS as reference. Regions of interest placed on source images and on six-echo parametric PDFF maps were colocalized to MRS voxel location. Accuracy using different numbers of echoes was assessed by regression and Bland–Altman analysis; slope, intercept, average bias, and R2 were calculated. The effect of age, sex, and body mass index (BMI) on hepatic PDFF accuracy was investigated using multivariate linear regression analyses.ResultsMRI closely agreed with MRS for all tested methods. For three- to six-echo methods, slope, regression intercept, average bias, and R2 were 1.01–0.99, 0.11–0.62%, 0.24–0.56%, and 0.981–0.982, respectively. Slope was closest to unity for the five-echo method. The two-echo method was least accurate, underestimating PDFF by an average of 2.93%, compared to an average of 0.23–0.69% for the other methods. Statistically significant but clinically nonmeaningful effects on PDFF error were found for subject BMI (P range: 0.0016 to 0.0783), male sex (P range: 0.015 to 0.037), and no statistically significant effect was found for subject age (P range: 0.18–0.24).ConclusionHepatic magnitude-based MRI PDFF estimates using three, four, five, and six echoes, and six-echo parametric maps are accurate compared to reference MRS values, and that accuracy is not meaningfully confounded by age, sex, or BMI.
A comparison of liver fat fraction measurement on MRI at 3T and 1.5T
PLOS ONE
Purpose Volumetric liver fat fraction (VLFF) measurements were made using the HepaFat-Scan® technique at 1.5T and 3T to determine the agreement between the measurements obtained at the two fields. Methods Sixty patients with type 2 diabetes (67% male, mean age 50.92 ± 6.56yrs) and thirty healthy volunteers (50% male, mean age 48.63 ± 6.32yrs) were scanned on 1.5T Aera and 3T Skyra (Siemens, Erlangen, Germany) MRI scanners on the same day using the HepaFat-Scan® gradient echo protocol with modification of echo times for 3T (TEs 2.38, 4.76, 7.14 ms at 1.5T and 1.2, 2.4, 3.6 ms at 3T). The 3T analyses were performed independently of the 1.5T analyses by a different analyst, blinded from the 1.5T results. Data were analysed for agreement and bias using Bland-Altman methods and intraclass correlation coefficients (ICC). A second cohort of 17 participants underwent interstudy repeatability assessment of VLFF measured by HepaFat-Scan® at 3T. Results A small, but statistically significant m...
Radiology, 2018
O besity is a major public health issue in the United States, with over two-thirds of American adults considered overweight or obese (1). Nonalcoholic fatty liver disease, widely considered the hepatic manifestation of metabolic syndrome (2), is an increasingly prevalent condition common in patients with obesity (3). Intracellular accumulation of triglycerides (hepatic steatosis) is the hallmark feature of nonalcoholic fatty liver disease, which can progress to nonalcoholic steatohepatitis and ultimately cirrhosis (4,5) while also increasing the risk of hepatocellular carcinoma (6). Bariatric surgery is an effective weight loss intervention in patients with obesity, reducing liver fat (7,8) and improving other health outcomes (9-11). Furthermore, use of a very low calorie diet (VLCD) prior to bariatric surgery facilitates surgery and may augment the degree of weight loss (12-14). However, the relationship between overall weight loss achieved by these treatments and decreases in liver fat content is not well understood, to our knowledge. A barrier to understanding these relationships has been the lack of reproducible, noninvasive methods to quantify liver fat. Liver biopsy has long been the reference standard for liver fat quantification (15) but is invasive. Traditional imaging methods, including conventional MRI, MR spectroscopy (16), and US (17), are of limited utility due to poor accuracy or technical difficulty (18). Advanced complex-based chemical shift-encoded (CSE) MRI methods for quantifying proton density fat fraction (PDFF) as a fundamental biomarker of liver fat concentration (19) have been developed and validated across multiple vendors
Abdominal radiology (New York), 2016
To compare agreement between region-of-interest (ROI)- and parametric map-based methods of hepatic proton density fat fraction (PDFF) estimation in adults with known or suspected hepatic steatosis secondary to chronic liver disease over a range of imaging and analysis conditions. In this IRB approved HIPAA compliant prospective single-site study, 31 adults with chronic liver disease undergoing clinical gadoxetic acid-enhanced liver magnetic resonance imaging at 3 T were recruited. Multi-echo gradient-echo imaging at flip angles of 10° and 50° was performed before and after administration of gadoxetic acid. Six echoes were acquired at successive nominally out-of-phase and in-phase echo times. PDFF was estimated with a nonlinear fitting algorithm using the first two, three, four, five, and (all) six echoes. Hence, 20 different imaging and analysis conditions were used (pre/post contrast x low/high flip angle x 2/3/4/5/6 echoes). For each condition, PDFF estimation was done in correspo...
Journal of magnetic resonance imaging : JMRI, 2015
To examine the reproducibility of quantitative magnetic resonance (MR) methods to estimate hepatic proton density fat-fraction (PDFF) at different magnetic field strengths. This Health Insurance Portability and Accountability Act (HIPAA)-compliant study was approved by the Institutional Review Board. Following informed consent, 25 severely obese subjects (mean body mass index [BMI]: 45 ± 4, range: 38-53 kg/m(2) ) were scanned at 1.5T and 3T on the same day. Two confounder-corrected multiecho chemical shift-encoded gradient-echo-based imaging methods were acquired to estimate PDFF over the entire liver: 3D complex-based (MRI-C) and 2D magnitude-based (MRI-M) MRI. Single-voxel MR spectroscopy (MRS) was performed in the right liver lobe. Using linear regression, pairwise comparisons of estimated PDFF were made between methods (MRI-C, MRI-M, MRS) at each field strength and for each method across field strengths. 1.5T vs. 3T regression analyses for MRI-C, MRI-M, and MRS PDFF measurements...
Journal of Magnetic Resonance Imaging, 2013
Purpose-To evaluate the effect of flip angle (FA) on accuracy and within-examination repeatability of hepatic proton-density fat fraction (PDFF) estimation with complex data-based magnetic resonance imaging (MRI). Materials and Methods-PDFF was estimated at 3T in thirty subjects, using two sets of five MRI sequences with FA from 1° to 5° in each set. One set used 7ms repetition time and acquired 6 echoes (TR7/E6); the other used 14ms and acquired 12 echoes (TR14/E12). For each FA in both sets, the accuracy of MRI-PDFF was assessed relative to MR spectroscopy (MRS)-PDFF using four regression parameters (slope, intercept, average bias, R 2). Each subject had four random sequences repeated; within-examination repeatability of MRI-PDFF for each FA was assessed with intraclass correlation coefficient (ICC). Pairwise comparisons were made using bootstrapbased tests. Results-Most FAs provided high MRI-PDFF estimation accuracy (intercept range-1.25-0.84, slope 0.89-1.06, average bias 0.24-1.65, R 2 0.85-0.97). Most comparisons of regression
European Journal of Clinical Nutrition, 2022
BACKGROUND/AIMS: The liver plays a central role in the fatty acid metabolism. Therefore, cirrhosis is prone to energy malnutrition and is associated with a poor prognosis. On the other hand, proton density fat fraction (PDFF) measured by magnetic resonance imaging (MRI) is a noninvasive and highly accurate method to quantify liver fat. In this study, we aimed to investigate the relationship between hepatic fat loss (HFL) and malnutrition by PDFF measurement in chronic liver disease (CLD). METHODS: In this retrospective single-center study of 485 patients with CLD, hepatic fat content was measured by MRI-PDFF, and CT-measured body composition and CONUT (Controlling Nutritional Status) score were used as nutritional assessment methods, respectively. RESULTS: In the overall cohort, MRI-PDFF was positively correlated with body fat mass, muscle mass and respectively. The HFL defined by PDFF ≤ 2.7% is 25%, and in multivariate analysis, decreased body fat mass and Triglyceride, and increased CONUT score were independent associated factors of HFL (p < 0.05, for all). Additionally, 35% of patients with cirrhosis (n = 107) had HFL, and the Cox proportional hazards model showed that Child-Pugh score and HFL were independent prognostic factors (p < 0.01, for both). CONCLUSIONS: MRI-PDFF was shown to be a useful indicator of malnutrition in cirrhosis reflecting body composition. Preservation of liver fat content in nutritional therapy may improve the prognosis of cirrhotic patients.
Abdominal Imaging, 2015
Purpose: The purpose of the present study was to determine liver, pancreas, kidney, and vertebral fat deposition in NAFLD patients by proton density fat fraction (PDFF) using magnetic resonance imaging (MRI) and to evaluate the relationships among them. Methods: A total of 41 biopsy-proven NAFLD patients underwent MRI-PDFF with IDEAL-IQ. MRI protocol included T1-independent volumetric multi-echo gradientecho imaging with T2* correction and spectral fat modeling. The MR examinations were performed on a 1.5 HDx MRI system. MRI-PDFF measurements were obtained from liver, pancreas, renal cortex and sinus, and vertebral body. Liver biopsy specimens were retrieved from the archives and evaluated by one pathologist according to NASH CRN. Results: The median age of the patients was 47 years. The median interval between liver biopsy and MRI examination was 16 days. Mean liver, pancreas, renal cortex, renal sinus, T12 and L1 vertebral body MRI-PDFFs were 18.7%, 5.7%, 1.7%, 51%, 43.2%, and 43.5%, respectively. No correlation between either liver MRI-PDFF or histological steatosis, and other organ MRI-PDFFs was observed. A good correlation between pancreas and vertebral body MRI-PDFFs, and pancreas and renal sinus MRI-PDFFs was observed. Diabetic patients had higher average pancreas MRI-PDFF compared to nondiabetics (12.2%, vs., 4.8%; P = 0.028). Conclusions: Pancreas and vertebral body MRI-PDFF is well correlated in NAFLD patients and both of them are higher in diabetic patients which may explain increased bone fractures in diabetics. MRI-PDFF can be used to demonstrate fat fractions of different organs and tissues and to understand fat metabolism.