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DOI: 10.1055/s-0039-1681298
DIFFERENTIATION OF PANCREATIC CYST TYPES BY ANALYSIS OF RHEOLOGICAL BEHAVIOR OF PANCREATIC CYST FLUID
Publikationsverlauf
Publikationsdatum:
18. März 2019 (online)
Aims:
Differentiation between mucinous and non-mucinous pancreatic cysts (PC) is exceedingly important, yet remains difficult.
The relative viscosity of PC fluid has proved useful for distinguishing mucinous from non-mucinous cysts.
We aimed to assess the utility of the rheological properties (measured by a rheometer) of PC fluid, as compared with standard-of-care analysis in differentiating PC types.
Methods:
Consecutive subjects with PC's underwent EUS-FNA. In addition to routine cyst fluid, a rheological behavior curve of the cyst fluid was generated.
PC's were classified as mucinous or non-mucinous based on surgical and/or clinical findings (presentation, imaging, fluid analyses and follow-up).
Results:
A total of 22 patients with PC underwent EUS-FNA.
Overall, 10 lesions (45.45%) were classified as mucinous, while 12 (54.54%) were classified as non-mucinous, 5 of which (22.72%) were considered pseudocysts.
For the rheological assessment, flow curves were drawn up, with the viscosity, η, plotted against the shear rate, γ.
Three types of rheologic curves were identified, where two types correlated with non-mucinous cysts, and the third type corresponding to mucinous cysts. Using the optimal cutoff value, the sensitivity, specificity, and accuracy of cyst fluid viscosity – based diagnosis of mucinous versus non-mucinous were 70%, 91.7%, and 81.8%, respectively. In comparison, string-sign test showed a sensitivity, specificity and accuracy of 50%, 66.7%, and 59.1%, respectively. The overall accuracy of the viscosity-based technique (81.8%) was greater than that of CEA (72.7%), cytology (72.7%) and string-sign (59.1%). When considering cyst fluid viscosity, jointly with patient age, the sensitivity and the accuracy increased to 100% and 95.5%, respectively, but the specificity remained 91.7%.
Conclusions:
Cyst fluid rheological analysis appears to accurately differentiate pancreatic cyst types. This simple and rapid diagnostic tool can be implemented on-site and provides for a low variability rate compared to the commonly used, subjective string sign technique.