title: Efficacy of stone density on noncontrast computed tomography in predicting the outcome of extracorporeal shock wave lithotripsy for patients with pancreatic stones.
abstract: OBJECTIVE
  Patients with chronic pancreatitis are managed by extracorporeal shock wave lithotripsy (ESWL) for pancreatic stones. Stone density on noncontrast computed tomography (NCCT) is used to predict stone composition and fragility, but no report investigating the pancreatic stone density has been documented. We aimed to assess the usefulness of pancreatic stone density on NCCT in predicting the ESWL outcome.
  
  
  METHODS
  We evaluated 128 consecutive patients with pancreatic stones who underwent ESWL. Pancreatic stone density on NCCT was measured in Hounsfield units. Patients with complete stone removal were compared with those with incomplete stone removal. Patient characteristics; imaging findings, including stone density; and interventions were evaluated as potential predictors. The optimal cutoff value of variables to differentiate complete removal from incomplete removal was determined by receiver operating characteristic analysis.
  
  
  RESULTS
  Complete stone removal was achieved in 66 patients (51.6%). When the density threshold was set at 820.5 Hounsfield units, complete stone removal was achieved in 52 patients (78.8%) with lower-density stones. In multivariate analysis, single stone (P = 0.007) and lower-density stone (P < 0.001) revealed significant association with complete stone removal.
  
  
  CONCLUSIONS
  The measurement of pancreatic stone density before therapy can help predict therapeutic outcomes.
authors.affiliation: From the Department of Gastroenterology and Nephrology, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ohyama
authors.forename: Rintaro
authors.initials: R
authors.lastname: Mikata
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ishihara
authors.forename: Toshio
authors.initials: T
authors.lastname: Tsuyuguchi
authors.forename: Yuji
authors.initials: Y
authors.lastname: Sakai
authors.forename: Harutoshi
authors.initials: H
authors.lastname: Sugiyama
authors.forename: Shin
authors.initials: S
authors.lastname: Yasui
authors.forename: Kiyofumi
authors.initials: K
authors.lastname: Ishii
authors.forename: Sadahiro
authors.initials: S
authors.lastname: Itoh
authors.forename: Takao
authors.initials: T
authors.lastname: Nishikawa
authors.forename: Yuto
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Osamu
authors.initials: O
authors.lastname: Yokosuka
mesh_terms: D000328:Adult; D000368:Aged; D019540:Area Under Curve; D002137:Calculi / Q000000981:diagnostic imaging* / Q000628:therapy*; D005260:Female; D006801:Humans; D020347:Lithiasis / Q000000981:diagnostic imaging* / Q000628:therapy*; D008096:Lithotripsy / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D050500:Pancreatitis, Chronic / Q000000981:diagnostic imaging* / Q000628:therapy*; D011237:Predictive Value of Tests; D012372:ROC Curve; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome