Primary intrahepatic lithiasis in western countries: role of ultrasound and comparison with MRI with MRCP.

OBJECTIVES

To study hepatobiliary expert ultrasound (US) in a cohort of suspected primary intrahepatic lithiasis (IHL) and to compare these findings with MRI/MRCP data.

METHODS

All patients with a diagnosis of primary-IHL based upon biological and, or, clinical symptoms who underwent US between 2008 and 2023 were retrospectively enrolled in two tertiary hepatobiliary centers. Clinical characteristics, available genetic and radiological features (expert US and MRCP) were recorded. Data were compared for the presence of comet-tail images or stones on US, between US and MRCP features and between imaging and patients' genetic status. Statistical analyses were performed with R software environment version 4.2.1, by univariate and multivariate analysis.

RESULTS

A total of 112 primary-IHL patients were included (mean age 43 years old ±14 and 55% women). US identified primary-IHL in 92/112 (82%) patients including intrahepatic biliary comet-tail in 82/112 (73%) and stones in 51/112 (46%). Among these, 66/112 (68%) had both US and MRCP. Lithiasis was identified in 60/76 US (79%) and 44/76 MRCP (58%). MRCP showed only stones in 22/76, 29%. Genetic testing was performed in 66/112 (58%) patients. Thirty-two (49%) of these patients had pathogenic ABCB4/MDR3 gene variants, 14/66 (21%) other pathogenic variants and 5/66 (5%) had unknown significant variants. No genetic abnormalities were found in 19/66 (29%). A multivariate logistic model with the comet-tail sign as an outcome showed that there was a significant negative correlation between other pathogenic genetic variants and the comet-tail phenotype ( P -value = 0.049).

CONCLUSION

US, and not MRCP, should be the primary diagnostic tool in suspected primary-IHL patients.