Objective: The objective of our study was to evaluate the detection rate of incidental pancreatic cysts on transabdominal ultrasound (TAUS) as well as factors influencing detection rates.
Materials and methods: Nine hundred thirty-eight patients with 1064 pancreatic cysts who underwent both TAUS and other imaging examinations including CT, MRI, or endoscopic ultrasound (EUS) were enrolled. We reviewed formal reports and assessed the effect of cyst size and location and the effect of the correlative images for cyst detection on TAUS. Statistical analyses were performed using the chi-square test, t test, and Cramér value (V).
Results: The overall detection rate of TAUS was 88.3% (940/1064). Cysts detected on TAUS were more often in younger patients and male patients. The detected cysts (median, 13 mm; interquartile range [IQR], 8-18 mm) were significantly larger than the undetected cysts (median, 10 mm; IQR, 6-14 mm) (p < 0.0001). However, waist circumference did not affect the detection rate. The detection rate was significantly improved from 49.2% (289/587) to 86.7% (830/957) when TAUS was performed after correlative imaging (p < 0.001). Although the detection rate for cysts in the entire pancreas was significantly increased with correlative images (p < 0.001), the detection rate for cysts in the uncinate process showed a much greater increase using correlative images (p < 0.001). However, detection of cysts in the tail of the pancreas showed the least improvement using correlative images. The detection rate was significantly improved with correlative images for cysts 25 mm or smaller.
Conclusion: Because the detection rate of TAUS for pancreatic cysts was significantly improved after CT, MRI, or EUS, TAUS could be a useful surveillance imaging tool for pancreatic cysts incidentally detected on CT, MRI, or EUS.
Keywords: MRI; pancreas; pancreatic cysts; surveillance; ultrasound.