title: Virtual analysis of pancreatic cystic lesion fluid content by ultrasound acoustic radiation force impulse quantification.
abstract: OBJECTIVE
  The purpose of this study was to prospectively evaluate the application of acoustic radiation force impulse (ARFI) imaging implemented with Virtual Touch tissue quantification (Siemens AG, Erlangen, Germany) in the study of pancreatic cystic lesions by using different analysis methods compared with the final diagnosis (pathologic or by magnetic resonance imaging and endoscopic sonographic findings).
  
  
  METHODS
  Thirty-eight patients with pancreatic cystic focal lesions (diameter >3 cm and located at a depth of 5.5 cm) were included in the study and underwent conventional sonography. For every patient, 5 measurements in the Virtual Touch tissue quantification region of interest were obtained. To distinguish mucinous (potentially malignant) from serous (mainly benign) cystic lesions, the result XXXX/0 was considered to mean simple liquids (comparable to water), and the accuracy of Virtual Touch tissue quantification in differentiating pancreatic cystic lesions was calculated. To consider a lesion as containing complex fluids (potentially mucinous), two different reading methods were applied: (1) at least 2 numerical values when obtaining 5 measurements; and (2) the prevalence of numerical values irrespective of the number of measurements. The sensitivity, specificity, positive and negative predictive values, and accuracy were calculated for the differential diagnosis between mucinous and nonmucinous cystic lesions.
  
  
  RESULTS
  By the first reading method, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in the group of cystic lesions were 68.8%, 77.3%, 68.8%, 77.3%, and 73.7%, respectively; by the second method, the values were 37.5%, 100%, 100%, 68.8%, and 73.3%.
  
  
  CONCLUSIONS
  Acoustic radiation force impulse imaging with Virtual Touch tissue quantification can have a role in the noninvasive characterization of pancreatic cystic lesions during conventional sonographic examinations.
authors.affiliation: Department of Radiology, University Hospital G. B. Rossi, University of Verona, Verona, Italy. mirko.donofrio@univr.it
authors.forename: Mirko
authors.initials: M
authors.lastname: D'Onofrio
authors.forename: Stefano
authors.initials: S
authors.lastname: Crosara
authors.forename: Stefano
authors.initials: S
authors.lastname: Canestrini
authors.forename: Emanuele
authors.initials: E
authors.lastname: Demozzi
authors.forename: Riccardo
authors.initials: R
authors.lastname: De Robertis
authors.forename: Roberto
authors.initials: R
authors.lastname: Salvia
authors.forename: Claudio
authors.initials: C
authors.lastname: Bassi
authors.forename: Roberto Pozzi
authors.initials: RP
authors.lastname: Mucelli
mesh_terms: D000328:Adult; D000368:Aged; D018291:Cystadenoma, Mucinous / Q000000981:diagnostic imaging; D018293:Cystadenoma, Serous / Q000000981:diagnostic imaging; D054459:Elasticity Imaging Techniques / Q000379:methods*; D019160:Endosonography; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010179:Pancreas / Q000000981:diagnostic imaging*; D010181:Pancreatic Cyst / Q000000981:diagnostic imaging* / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging; D011446:Prospective Studies; D012680:Sensitivity and Specificity