Quantitative MRI to Assess Portal Pressure in Patients With Liver Disease: Validation at 3 T

Hepatic venous pressure gradient (HVPG) is the gold standard for assessing portal hypertension (PH). We previously demonstrated that a bivariate MRI model combining liver T₁ and splenic artery velocity at 1.5 T correlates with HVPG. This study aimed to evaluate this model at 3 T and investigate additional splanchnic MRI measures as potential non-invasive markers of portal pressure. Data from 40 participants (15 metabolic dysfunction-associated steatotic liver disease [MASLD]/13 alcohol-related liver disease [ArLD]/12 other, 55 ± 14 years) scanned at 1.5 T (retrospective) and 42 participants (21 MASLD/14 ArLD/7 other, 60 ± 12 years) scanned prospectively at 3 T who underwent clinical HVPG measurement were analysed. Liver and spleen iron-corrected T₁ (cT₁) were acquired using fat-suppressed spin-echo echo-planar T₁ mapping, and splanchnic haemodynamics were assessed using phase-contrast MRI. Correlations between MRI parameters and HVPG were assessed, and previously derived univariate (liver cT₁) and bivariate (liver cT₁ + splenic artery velocity) models were evaluated using receiver operating characteristic (ROC) analysis for PH (HVPG ≥ 5 mmHg), clinically significant PH (CSPH; HVPG ≥ 10 mmHg) and increased risk of mortality (HVPG ≥ 15 mmHg). Liver cT₁ at 3 T showed a strong positive correlation with HVPG across the full range (0-23 mmHg; R = 0.73, p < 0.0001). After field adjustment, pooled 1.5 and 3 T liver cT₁ maintained a strong correlation with HVPG (R = 0.76, p < 0.0001). At 3 T, the univariate liver cT₁ model outperformed the bivariate model, achieving AUROCs of 0.74, 0.86 and 0.91 for detecting PH, CSPH and HVPG ≥ 15 mmHg, respectively. In contrast, spleen cT₁ and superior mesenteric artery velocity correlated with HVPG only up to ~15 mmHg, after which values plateaued or declined. Liver cT₁ MRI at 3 T provides a surrogate of portal pressure across the full HVPG range and outperforms a previously proposed bivariate model. Spleen and splanchnic haemodynamic measures demonstrate a ceiling effect at higher portal pressures > 15 mmHg.