Liver Fat Content Measurement with Quantitative CT Validated against MRI Proton Density Fat Fraction: A Prospective Study of 400 Healthy Volunteers

Abstract

N onalcoholic fatty liver disease has a global prevalence of 25% and is defined as the intracellular accumulation of fat in the liver parenchyma exceeding 5% in the absence of competing causes such as chronic viral hepatitis, druginduced steatosis, or other chronic liver diseases such as autoimmune hepatitis, hemochromatosis, or alcohol abuse (1,2). Nonalcoholic fatty liver disease is considered an important cause of chronic liver disease, such as nonalcoholic steatohepatitis and cirrhosis, and even hepatocellular carcinoma (3). People with nonalcoholic fatty liver disease tend to also have obesity, diabetes, dyslipidemia, and hypertension, and are at higher risk of cardiovascular disease (1). Accurate and reliable quantification of liver fat content is critical for the diagnosis, treatment, and monitoring of nonalcoholic fatty liver disease.Liver biopsy has long been the reference standard for assessment of liver fat content, although its application is restricted because of its invasive nature and high cost (4). Noninvasive techniques include US, CT, and MRI. US is an inexpensive and convenient diagnostic tool for nonalcoholic fatty liver disease, but it is semiquantitative and relatively insensitive to individuals with liver fat content less than 20% (5-7). Traditionally, CT was considered accurate for moderate-to-severe steatosis but insensitive to mild steatosis (8,9), and the results are susceptible to variable scanning conditions such as different tube voltages and CT scanners from different manufacturers (9,10). MRI methods, including proton MR spectroscopy and the emerging technique of chemical shift-encoded (CSE) MRI, are regarded as the most accurate noninvasive techniques for the evaluation of liver fat (11)(12)(13)(14)(15). Proton MR spectroscopy and CSE MRI quantify liver fat directly in terms of the proton density fat fraction (PDFF), defined as the ratio of the signal strength from fat to the total signal from fat and water (11,16).

Coronary artery disease and non‐alcoholic fatty liver disease: Clinical correlation using computed tomography coronary calcium scans

“…1). These imaging modalities have been validated for monitoring of NAFLD in previous studies 14–16 . Liver imaging had to have been performed within 5 years of the CT CAC scan for inclusion in the study.…”

“…These imaging modalities have been validated for monitoring of NAFLD in previous studies. [14][15][16] Liver imaging had to have been performed within 5 years of the CT CAC scan for inclusion in the study. For these patients, gender, coronary calcium score, triglycerides, total cholesterol, high-density lipoproteins (HDL), LDL, height, weight, platelets, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase, and total bilirubin were obtained from patient charts in EPIC.…”

Pancreatic Fat is not significantly correlated with β-cell Dysfunction in Patients with new-onset Type 2 Diabetes Mellitus using quantitative Computed Tomography

“…Using the export function of the QCT Pro software database, the field uniformity correction (FUC), the bone mineral density (BMD) value of three measurements and the corresponding calibration slope were derived. QCT measurements of hepatic or pancreatic tissue using the Mindways spine module software were converted into percentage fat measurements using a published method for measuring liver fat and pancreatic fat by Cheng X et al and calculated using the following equation [20][21][22]:…”

“…The measurement of fat is intuitive and accurate, and the accuracy of measuring abdominal fat with QCT is similar to that of MRI. There have been more studies on liver fat deposition 19 - 21 and fewer on the measurement of pancreatic fat deposition by QCT 22 . We are interested in whether QCT can be used as an economical, efficient and accurate research tool to assess the extent of pancreatic fat deposition and its relationship to islet β-cell function.…”

Usefulness of Different Imaging Modalities in Evaluation of Patients with Non-Alcoholic Fatty Liver Disease

“…One is the use of a standardized calibration phantom, placed beneath the patients back during the CT examination. In a recent study from 2020, Guo et al provided evidence that the utilization of this protocol enables the calculation of hepatic steatosis far more accurately, with sensitivity and specificity of 76% and 85%, respectively, for the detection of mild steatosis (involving at least 5% of hepatocytes), and 85% and 98%, respectively, for the detection of moderate steatosis (involving at least 14% of hepatocytes) [ 16 ]. The clinical usefulness of this method is especially supported by relatively high positive and negative predictive values of 78% and 83%, respectively, for mild steatosis, and 82% and 97%, respectively, for moderate steatosis.…”