Assessing IgG4-related autoimmune pancreatitis with contrast-enhanced ultrasonography based on time-intensity curve:...

The aim of this study was to investigate the changes in various parameters of contrast-enhanced ultrasound (CEUS) before and after treatment in patients with IgG4-related autoimmune pancreatitis (IgG4-AIP), and to identify potential indicators that can assist in evaluating disease activity.

In this prospective study, we enrolled patients diagnosed with IgG4-AIP from June 2021 to November 2022. Demographic characteristics, clinical features, laboratory tests were recorded. Baseline and follow-up, conventional ultrasound and CEUS were conducted. Additionally, a region of interest (ROI) within lesions, pancreatic head, pancreatic body, and pancreatic tail was taken to draw time-intensity curves (TIC) and parameters of TIC were recorded and analysed.

Seventy-three active IgG4-AIP patients were enrolled. Follow-up, a notable decrease in the size of the pancreatic lesion was observed with a reduction in the maximum diameter from 4.3 ± 2.0 cm to 1.7 ± 1.6 cm (p=0.01). The results revealed a statistically significant increase in peak intensity (PI) in the head, body, and tail regions of the pancreas (p<0.001), along with a significant rise in the area under the curve (AUC) in the tail region of the pancreas (p=0.029) after treatment compared to baseline. In contrast, no statistically significant differences were observed in other parameters of TIC. A significant increase of PI was observed in 12 patients with diffuse IgG4-AIP following treatment. Following treatment, there was a significant increase in PI in the focal area among the 12 patients with focal lesions.

CEUS based on TIC holds great potential for assessing response to treatment in patients with IgG4 AIP.