title: Explanations for the heterogeneity of splenic enhancement derived from blood flow kinetic measurements using dynamic contrast-enhanced CT (DCE-CT).
abstract: BACKGROUND
  The heterogeneity of splenic computed tomography (CT) attenuation is still not fully understood. A differentiation of these enhancement patterns and other conditions such as diffuse spleen infiltration can be challenging.
  
  
  OBJECTIVE
  To understand the underlying physiological mechanisms of flow heterogeneity in normal and cirrhosis patients by quantifying perfusion parameters such as blood flow (BF), blood volume (BV), time to peak (TTP), flow extraction product (K(trans)), and mean transit time (MTT) using dynamic contrast-enhanced CT (DCE-CT).
  
  
  METHODS
  Sixteen patients without splenic or hepatic disease and 16 patients with liver cirrhosis were retrospectively analyzed. Perfusion assessment included rapidly and slowly enhancing areas of the spleen, the entire splenic volume, as well as intra- and inter-observer reliability analysis.
  
  
  RESULTS
  Significant differences between rapidly and slowly enhancing areas were found in controls for BF (109.8 mL/100 mL/min vs. 63.5 mL/100 mL/min), BV (37.1 mL/100 mL vs. 18.9 mL/100 mL), MTT (10.1 s vs. 13.0 s), but not for TTP (17.6 s vs. 18.6 s) and K(trans) (40.3 mL/100 mL/min vs. 44.7 mL/100 mL/min). In cirrhotic patients, differences proved significant for BF (90.5 mL/100 mL/min vs. 58.7 mL/100 mL/min), BV (17.5 mL/100 mL vs. 8.8 mL/100 mL), but not for K(trans) (60.9 mL/100 mL/min vs. 50.5 mL/100 mL/min), TTP (18.8 s vs. 20.0 s), and MTT (11.4 s vs. 14.2 s). Differences between rapidly enhancing areas in controls and cirrhotic patients reached a significant level for BV and K(trans).
  
  
  CONCLUSIONS
  Preliminary results suggest that DCE-CT-based splenic perfusion measurements enable detection of different blood flow kinetics presumed to represent the complex and characteristic architecture of splenic vascular channels. It is the separate analysis of flow kinetics through the rapidly enhancing channels that allow for additional differentiation between controls and patients with portal hypertension.
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Tuebingen, Germany alexander.sauter@klinikum.uni-tuebingen.de.
authors.forename: Alexander W
authors.initials: AW
authors.lastname: Sauter
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Tuebingen, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Spira
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Tuebingen, Germany.
authors.forename: Maximilian
authors.initials: M
authors.lastname: Schulze
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Tuebingen, Germany.
authors.forename: Marius S
authors.initials: MS
authors.lastname: Horger
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity / Q000502:physiology; D001810:Blood Volume / Q000502:physiology; D003287:Contrast Media; D005260:Female; D006801:Humans; D007472:Iohexol / Q000031:analogs & derivatives; D008103:Liver Cirrhosis / Q000000981:diagnostic imaging / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011856:Radiographic Image Enhancement / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013154:Spleen / Q000098:blood supply* / Q000000981:diagnostic imaging* / Q000503:physiopathology; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide
keywords: Spleen; computed tomography; contrast media; perfusion imaging; portal hypertension