title: EUS spectrum analysis for in vivo characterization of pancreatic and lymph node tissue: a pilot study.
abstract: BACKGROUND
  EUS is limited by variability in the examiner's subjective interpretation of B-scan images to differentiate among normal, inflammatory, and malignant tissue. By using information otherwise discarded by conventional EUS systems, quantitative spectral analysis of the raw radiofrequency (RF) signals underlying EUS images enables tissue to be characterized more objectively.
  
  
  OBJECTIVE
  Our purpose was to determine the feasibility of using spectral analysis of EUS data for characterization of pancreatic tissue and lymph nodes.
  
  
  METHODS
  A pilot study of eligible patients was conducted to analyze the RF data obtained during EUS by using spectral parameters.
  
  
  METHODS
  Twenty-one subjects who underwent EUS of the esophagus, stomach, pancreas, and surrounding intra-abdominal and mediastinal lymph nodes.
  
  
  METHODS
  Linear regression parameters of calibrated power spectra of the RF signals were tested to differentiate normal pancreas from chronic pancreatitis and from pancreatic cancer as well as benign from malignant-appearing lymph nodes.
  
  
  RESULTS
  The mean intercept, slope, and midband fit of the spectra differed significantly among normal pancreas, adenocarcinoma, and chronic pancreatitis when all were compared with each other (P < .01). On direct comparison, mean midband fit for adenocarcinoma differed significantly from that for chronic pancreatitis (P < .05). For lymph nodes, mean midband fit and intercept differed significantly between benign- and malignant-appearing lymph nodes (P < .01 and P < .05, respectively).
  
  
  CONCLUSIONS
  Small sample population and spatial averaging inherent to this technique.
  
  
  CONCLUSIONS
  Mean spectral parameters in EUS imaging can provide a noninvasive method to discriminate normal from diseased pancreas and lymph nodes.
authors.affiliation: Division of Gastroenterology, University Hospitals Case Medical Center and Case Western Reserve University, Cleveland, Ohio 44106-5066, USA.
authors.forename: Ronald E
authors.initials: RE
authors.lastname: Kumon
authors.forename: Kayode
authors.initials: K
authors.lastname: Olowe
authors.forename: Ashley L
authors.initials: AL
authors.lastname: Faulx
authors.forename: Farees T
authors.initials: FT
authors.lastname: Farooq
authors.forename: Victor K
authors.initials: VK
authors.lastname: Chen
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhou
authors.forename: Richard C K
authors.initials: RC
authors.lastname: Wong
authors.forename: Gerard A
authors.initials: GA
authors.lastname: Isenberg
authors.forename: Michael V
authors.initials: MV
authors.lastname: Sivak
authors.forename: Amitabh
authors.initials: A
authors.lastname: Chak
authors.forename: Cheri X
authors.initials: CX
authors.lastname: Deng
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019160:Endosonography; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008198:Lymph Nodes / Q000000981:diagnostic imaging* / Q000473:pathology; D008207:Lymphatic Metastasis / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging; D010865:Pilot Projects