Background It is commonly accepted that abdominal ultrasound imaging is impaired in subjects with obesity, but data on the diagnostic impact of adiposity on examination accuracy are scarce. High-performance ultrasound probes implying innovative techniques to reduce disruptive effects in obese patients aim at decreasing the effect of anthropometry on imaging quality.
Aims The present study evaluated whether obesity relates to impaired ultrasound assessment of hepatic and renal anatomy and vascularization and whether this is affected by probe performance.
Methods Lean and obese subjects (n = 40; 58 % female) were categorized according to body mass index (BMI, 21 to 48 kg/m²). A highly standardized ultrasound examination of the abdomen was performed by trained examiners using three different transducers in randomized order (standard probe, i.e. single crystal curved 1D, 1.0-5.7 MHz, versus two high-performance probes, i.e. multi-D piezoceramic curved, 1.0-3.5 MHz, and matrix array, single crystal curved, 4 MHz). Quality of B-mode and duplex ultrasound were assessed using a custom scoring approach for depiction of anatomy and vascularization of the liver and right kidney.
Results Across probes, imaging quality of hepatic and renal anatomy was inversely related with BMI (r < −0.35, P < 0.03). Age, sex, and BMI explained 51 % of the variance of the ultrasound quality score, with β = −0.35, P < 0.0001 for BMI. Compared to the standard probe, high-performance ultrasound transducers allow for a better depiction of renal and liver anatomy in subjects above BMI 35 kg/m² (n = 20, all P < 0.05), resulting in a less pronounced deterioration of imaging quality with increased BMI as observed using the standard probe (P = 0.004).
Conclusion Obesity impairs ultrasound imaging of hepatic and renal anatomy and affects diagnostic accuracy. The use of high-performance ultrasound probes leads to a more complete depiction of hepatic and renal anatomy in subjects with greater BMI.
