Novel multi-parametric diagnosis of non-alcoholic fatty liver disease using ultrasonography, body mass index, and Fib-4 index

Background: Shear wave speed (SWS), shear wave dispersion (SWD), and attenuation imaging (ATI) are new diagnostic parameters for non-alcoholic fatty liver disease. To differentiate between non-alcoholic steatohepatitis (NASH) and non-alcoholic fatty liver (NAFL), we developed a clinical index we refer to as the "NASH pentagon" consisting of the 3 abovementioned parameters, body mass index (BMI), and Fib-4 index.

Aim: To investigate whether the area of the NASH pentagon we propose is useful in discriminating between NASH and NAFL.

Methods: This non-invasive, prospective, observational study included patients diagnosed with fatty liver by abdominal ultrasound between September 2021 and August 2022 in whom shear wave elastography, SWD, and ATI were measured. Histological diagnosis based on liver biopsy was performed in 31 patients. The large pentagon group (LP group) and the small pentagon group (SP group), using an area of 100 as the cutoff, were compared; the NASH diagnosis rate was also investigated. In patients with a histologically confirmed diagnosis, receiver-operating characteristic (ROC) curve analyses were performed.

Results: One hundred-seven patients (61 men, 46 women; mean age 55.1 years; mean BMI 26.8 kg/m²) were assessed. The LP group was significantly older (mean age: 60.8 ± 15.2 years vs 46.4 ± 13.2 years; P < 0.0001). Twenty-five patients who underwent liver biopsies were diagnosed with NASH, and 6 were diagnosed with NAFL. On ROC curve analyses, the areas under the ROC curves for SWS, dispersion slope, ATI value, BMI, Fib-4 index, and the area of the NASH pentagon were 0.88000, 0.82000, 0.58730, 0.63000, 0.59333, and 0.93651, respectively; the largest was that for the area of the NASH pentagon.

Conclusion: The NASH pentagon area appears useful for discriminating between patients with NASH and those with NAFL.