Splenic T_1ρ as a noninvasive biomarker for portal hypertension

Background: There is a need for noninvasive methods for the diagnosis and monitoring of portal hypertension (PH). Purpose: To 1) assess the correlation of liver and spleen T₁ and T_1ρ measurements with portal pressures in patients with chronic liver disease, and 2) to compare the diagnostic performance of the relaxation parameters with radiological assessment of PH. Study Type: Prospective. Subjects: Twenty-five patients (M/F 16/9, mean age 56 years, range 21–78 years) undergoing portal pressure (hepatic venous pressure gradient [HVPG]) measurements. Field Strength/Sequence: 1.5T abdominal MRI scan, including T_1ρ and T₁ mapping. Assessment: Liver and spleen T_1ρ and T₁, radiological PH score, and (normalized) spleen length were evaluated. Statistical Tests: Spearman correlation of all MRI parameters with HVPG was assessed. The diagnostic performance of the assessed parameters for prediction of PH (HVPG ≥5 mmHg) and clinically significant PH (CSPH, HVPG ≥10 mmHg) was determined by receiver operating characteristic (ROC) analysis. Results: The mean HVPG measurement was 7.8 ± 5.3 mmHg (PH, n = 18 [72%] including CSPH, n = 9 [36%]). PH score, (normalized) spleen length and spleen T_1ρ significantly correlated with HVPG, with the strongest correlation found for spleen T_1ρ (r = 0.613, P = 0.001). Spleen T_1ρ was the only parameter that showed significant diagnostic performance for assessment of PH (area under the curve [AUC] 0.817, P = 0.015) and CSPH (AUC = 0.778, P = 0.024). Normalized spleen length also showed significant diagnostic performance for prediction of CSPH, with a slightly lower AUC (= 0.764, P = 0.031). The radiological PH score, T_1ρ and T₁ of the liver and T₁ of the spleen, did not show significant diagnostic performance for assessment of CSPH (P > 0.075). Data Conclusion: Spleen T_1ρ showed a significant correlation with portal pressure and showed improved diagnostic performance for prediction of CSPH compared to radiological assessment. These initial results need confirmation in a larger cohort. Level of Evidence: 1. Technical Efficacy Stage: 2. J. Magn. Reson. Imaging 2020;52:787–794.