Introduction Accurate non-invasive techniques for imaging portal hypertension (PHT) have long been the goal of hepatologists. However the sensitivity of standard ultrasound (US) alone is too low to achieve this. The combined use of elastography with US to detect PHT has not been investigated. ARFI (Virtual Touch©) elastography is a novel validated technique for measuring liver stiffness (LS), with practical advantages over transient elastography including real-time scanning. We report our experience of this technique in assessing PHT in a consecutive secondary care cohort.
Aims To establish whether the addition of LS estimation by ARFI to conventional US Doppler assessment of the spleno-portal venous system can reliably predict the presence of significant endoscopic PHT.
Methods Conventional US and elastography were performed simultaneously at one session by a single radiologist, using a Siemens Acuson S2000TM and 4C1 probe 4 MHz transducer and a standard, validated 10 observation right lobe ARFI technique. Within the study period, 82/108 chronic liver disease (CLD) patients (60 hospitalised and 48 outpatients) underwent both elastography and upper GI endoscopy. Standard US data collected included spleen size, portal vein Doppler flow velocity, direction and waveform, presence of collaterals, and platelet count.
Results Significant endoscopic PHT, defined as oesophageal/gastric varices and/or moderate to severe portal hypertensive gastropathy, was seen in 34/82 patients (41%). Median LS measured by shear velocity was significantly higher in the PHT group (2.9 vs 2.2 m/s, p<0.001). A 10 point “SPVD” (spleen-platelets/portal vein Doppler) scoring system, devised to include all US parameters and platelet count, showed significantly higher median scores in PHT (3 vs 1, p<0.001). Multiple logistic regression analysis demonstrated that both ARFI and SPVD score were independent predictors of PHT (OR, 95% CI 2.73, 1.22 to 6.13, p=0.02; and 3.08, 1.89 to 5.02, p<0.001, respectively). AUROC analysis showed that a best fit combination of ARFI+SPVD score showed the highest overall predictive value at 0.91, compared with ARFI or SPVD alone (0.72 and 0.87, respectively).
Conclusion In this retrospective “real world” study the addition of ARFI to standard US parameters using a combined scoring system achieved high (>90%) predictive value for the non-invasive detection of endoscopic PHT. A further prospective study, with refinement of US Doppler technique, is now in progress to confirm these promising results. Single session ARFI+US may accurately guide PHT diagnosis and selection for endoscopic surveillance in CLD.
Competing interests None declared.