Clinico-radiological Differences between Porto-sinusoidal Vascular Disorder and Cirrhosis.

BACKGROUND & AIMS: Porto-sinusoidal vascular disorder (PSVD) is an underrecognized cause of portal hypertension often misdiagnosed as cirrhosis. This study aims to compare CT-derived volumetric data and laboratory features between PSVD and cirrhosis and to develop and validate a noninvasive model to facilitate the clinical suspicion of PSVD. METHODS: This retrospective study included an Eastern cohort (Korea; 101 PSVD, 202 cirrhosis) and a Western cohort (France; 45 PSVD, 100 cirrhosis). All patients exhibited signs of portal hypertension and were matched for its severity. Spleen volumes were automatically quantified on CT and normalized to personalized reference volumes. Volumetric and laboratory features were compared between the two disease groups. A multivariable conditional logistic regression model (PSVD-VL), incorporating standardized spleen volume, aspartate aminotransferase, platelet count, and international normalized ratio, was developed in the Eastern cohort and validated in the Western cohort. RESULTS: Median standardized spleen volume was significantly greater in PSVD than in cirrhosis across both Eastern (5.14 vs. 3.59, p<0.001) and Western (5.20 vs. 3.46, p<0.001) cohorts. Conversely, hepatic synthetic function and hepatocellular injury markers were better preserved in PSVD. The PSVD-VL model demonstrated robust diagnostic performance with an area under the receiver operating characteristic curve of 0.86 (95% CI: 0.81-0.91) in the Eastern cohort and 0.79 (95% CI: 0.71-0.87) in the Western cohort. CONCLUSIONS: PSVD exhibits disproportionately larger spleen volumes despite more preserved liver function compared to cirrhosis of similar portal hypertension severity. Integration of CT-derived spleen volume and routine laboratory parameters may serve as an effective clinical trigger to prompt diagnostic liver biopsy. IMPACT AND IMPLICATIONS: Porto-sinusoidal vascular disorder (PSVD) is an underrecognized cause of portal hypertension that is frequently misdiagnosed as cirrhosis because of overlapping clinical and imaging features. In this multicenter study across Eastern and Western cohorts, we show that PSVD is characterized by disproportionately larger spleen volumes despite more preserved hepatic function, and that combining CT-derived spleen volume with routine laboratory parameters enables noninvasive discrimination between PSVD and cirrhosis. These findings are important for clinicians and researchers because delayed or missed recognition of PSVD may lead to inappropriate disease labeling and management. The proposed PSVD-VL model may serve as a practical clinical trigger to prompt consideration of PSVD and guide the use of diagnostic liver biopsy in patients with portal hypertension.