The influence of acute physical effort on liver stiffness estimation using virtual touch quantification (VTQ). preliminary results

Abstract

Food intake and acutely decompensated cardiac failure may impair liver stiffness estimations, mainly because thesemethods are influenced by liver blood flow variation encountered in these conditions. It is well known that also during physicaleffort liver blood flow changes, due to the redistribution of blood flow mainly to the skeletal muscles. The aim of this study isto assess the change of liver shear- wave velocities immediately after cessation of an acute physical effort. A secondary aimwas to find the proper timing for accurate liver stiffness estimation after physical exhaustion. Material and methods: Livershear-wave velocities were measured using virtual touch quantification (VTQ) in seven apparently healthy volunteers, in fastingconditions. All subjects underwent a complete abdominal ultrasound study, including the liver VTQ. Then, all subjectsperformed a spiroergometry and thereafter, another series of three liver shear-wave velocity measurements were performed:immediately after spiroergometry, five min, and ten min after spiroergometry, respectively. Results: Before spiroergoemetry,the mean liver shear-wave velocity was 1.05±0.12 m/sec. Immediately after spiroergometry, mean liver shear-wave velocitiesincreased significantly, measuring 1.34±0.16 m/sec (p <0.01). The mean liver shear-wave velocities at five and ten minutesafter exhausting were 1.23±0.14 m/sec and 1.05±0.11 m/sec respectively. Conclusions: Liver stiffness estimation using VTQwas influenced by acute physical exercise in our study group. Despite the small number of subjects, the preliminary resultsshow that if patients had done physical effort before VTQ elastography, they should rest at least ten minutes before reliableliver stiffness estimations can be performed.