A Comparison of Single Dimension and Volume Measurements in the Risk Stratification of Pancreatic Cystic Lesions

Abstract

The incidence of pancreatic cystic lesions (PCLs) has been rising due to improvements in imaging. Of these, intraductal papillary mucinous neoplasms (IPMNs) are the most common and are thought to contribute to almost 20% of pancreatic adenocarcinomas. All major society guidelines for the management of IPMNs use size defined by maximum diameter as the primary determinant of whether surveillance or surgical resection is recommended. However, there is no consensus on how these measurements should be obtained or whether a single imaging modality is superior. Furthermore, the largest diameter may fail to capture the complexity of PCLs, as most are not perfectly spherical. This article reviews current PCL measurement techniques in CT, MRI, and EUS and posits volume as a possible alternative to the largest diameter.

Keywords: CT; EUS; IPMN; MRCP; MRI; maximum diameter; pancreatic cancer; pancreatic cystic lesion; volume.

Figure 1

(A) spherical volume = π × R1³/6; (B) ellipsoid volume = R1 × R2 × R3 × π/6.

Figure 2

While the maximum length measurements on each of the X-Y-Z axes correlate well to overall spherical shape of figure (A), they do not correlate as well to the non-spherical shape of figure (B).