The Deep Abdominal Ultrasound Transducer (DAX) Increases the Success Rate and Diagnostic Accuracy of Shear Wave Elastography for Liver Fibrosis Assessment in Patients with Obesity-a Prospective Biopsy-Controlled Study

SummaryBackgroundObesity impacts the diagnostic accuracy of shear wave elastography (SWE). A deep abdominal ultrasound transducer (DAX) capable of point (pSWE) and two‐dimensional (2D)‐SWE has recently been introduced to address this issue.MethodsWe performed a prospective study in a cohort of mostly patients with obesity undergoing liver biopsy with a high prevalence of metabolic dysfunction‐associate steatotic liver disease (MASLD). Liver stiffness measurement (LSM) was measured using vibration‐controlled transient elastography (VCTE), as well as pSWE and 2D SWE on the standard (5C1) and the DAX transducers.ResultsWe included 129 patients with paired LSM and liver biopsy: median age 44.0 years, 82 (63.6%) women, median BMI: 43.2 kg/m2. Histologic fibrosis stages: F0: N = 55 (42.6%), F1: N = 14 (10.9%), F2: N = 50 (38.8%), F3: N = 2 (1.6%), F4: N = 8 (6.2%). VCTE‐LSM failed (N = 13) or were unreliable (IQR/median ≤30% in ≥7.1 kPa, N = 14) in 20.9% of patients. The Pearson correlation of reliable VCTE‐LSM with both pSWE and 2D SWE was strong (all >0.78). The diagnostic accuracy for all LSM techniques was poor for significant fibrosis (≥F2, AUC: 0.54–0.63); however, it was good to excellent for advanced fibrosis (≥F3, AUC: 0.87–0.99) and cirrhosis (F4, AUC: 0.86–1.00). In intention‐to‐diagnose analysis, pSWE on DAX was significantly superior to VCTE‐LSM.ConclusionspSWE‐ and 2D‐SWE enable the non‐invasive identification of advanced fibrosis and cirrhosis in patients with obese MASLD. The use of the DAX transducer for acoustic radiation force imaging (ARFI)‐LSM avoids technical failures in an obese population and subsequently offers advantages over VCTE‐LSM for the evaluation of fibrosis in an obese MASLD population at risk for fibrosis.