Objective To explore the differences of related indicators between patients with hepatic sinusoidal obstruction syndrome (HSOS) and those without hepatic sinusoidal obstruction syndrome in patients with gastrointestinal malignant tumors receiving chemotherapy, and to analyze the imaging features of HSOS with gadoxetic acid-enhanced MRI.

Methods We retrospectively analyzed the clinical and imaging data of 69 patients with gastrointestinal malignancies who had undergone neoadjuvant chemotherapy in Zhongshan hospital, Fudan University from July 2013 to July 2021. Each observer used a 5-point scale to assess the confidence level of the presence of hepatobiliary phase heterogeneous low signal in gadoxetic acid-enhanced MRI. The patients with a score of 4 or 5 on MRI were regarded as HSOS-positive diagnosis, and the rest were HSOS-negative. Using t test or Mann-Whitney U test to compare both groups of laboratory data and hepatobiliary specific phase-related parameters. Describing the imaging signs of patients in the HSOS-positive group.

Results Interobserver agreement was 0.80. According to the scoring results, 20 patients were included in the HSOS-positive group and 49 patients were included in the HSOS-negative group. There was statistical differences in PLT between the two groups (P < 0.05), but no statistical differences in the remaining laboratory data. The hepatobiliary specific phase-related parameters SIPre of the HSOS-positive group and the HSOS-negative group respectively were 136.10±28.62, 141.90±28.52, and there was no statistical difference, while SIHbp were 204.40±53.29, 274.35±66.83, and RE were 0.51±0.24, 0.93±0.24, which were statistically significant difference (P < 0.05). Among the 20 patients in the HSOS-positive group, hepatic distribution was diffuse in 11 (55%), patchy in 9 (45%). In the distribution of lesions, lobar predominance was right in 8 patients (40%), both right and left in 12 patients (60%). Three of the patients were followed up with gadoxetic acid-enhanced MRI after the end of chemotherapy, and the heterogeneous low signal were relieved or disappeared.

Conclusions Heterogeneous low signal on hepatobiliary specific-phase of gadoxetic acid-enhanced MRI indicates the presence of HSOS caused by neoadjuvant chemotherapy. MRI hepatobiliary specific phase-related parameters SIHbp and RE can effectively identify HSOS.