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.