Abstract
PURPOSE: This study aimed to evaluate the clinical utility of transabdominal ultrasound (TAUS) for pancreatic cyst surveillance by assessing its concordance with follow-up computed tomography (CT) and magnetic resonance imaging (MRI) findings and the associated risk of malignancy. METHODS: This retrospective study included 523 patients who underwent TAUS for pancreatic cysts (≥1 cm), followed by contrast-enhanced CT or MRI within a 1-year interval between 2021 and 2022. Cysts were classified as high-risk if they exhibited any high-risk stigmata or worrisome features, and as low-risk otherwise, based on the 2024 international consensus guidelines. TAUS classifications were compared with those from CT/MRI. In a subset of 164 patients with reference standards, malignancy rates were compared between high- and low-risk cysts on TAUS. RESULTS: The overall cyst identification rate on TAUS was 88.7% (464/523), with identification rates higher in patients with lower body mass index (23.8±3.3 kg/m2 vs. 29.2±3.3 kg/m2, P=0.003) and in those with non-tail cyst locations (92.7% [406/438] vs. 68.2% [58/85] for tail lesions, P<0.001). Among identified cysts, 86 (18.5%) were classified as high-risk and 378 (81.5%) as low-risk. TAUS-based risk classification demonstrated significant correlation with CT/MRI classification (P<0.001). The likelihood of a high-risk cyst on CT/MRI increased with the number of high-risk or worrisome features identified on TAUS. Malignancy rates were significantly higher in high-risk cysts than in low-risk cysts based on TAUS assessment (12.5% [4/32] vs. 1.5% [2/132], P=0.014). CONCLUSION: TAUS may serve as a useful noninvasive imaging modality for pancreatic cyst surveillance, particularly in patients with favorable visualization conditions. TAUS features correlated well with CT/MRI findings in identifying high-risk pancreatic cysts, and the presence of multiple worrisome features on TAUS was associated with an increased likelihood of high-risk classification on subsequent cross-sectional imaging.