title: Dose reduction for semi-automated volumetry of hepatic metastasis in MDCT studies.
abstract: OBJECTIVE
  To investigate the performance of semi-automated measurements (RECIST, volume) of hepatic metastases in multidetector-row computed tomography (MDCT) under normal-dose- and simulated low-dose-protocols.
  
  
  METHODS
  Thirty-five patients (67 +/- 13 years) with a total of 79 hepatic metastases underwent 16-MDCT (120 kv, 160 mAseff, pitch 1, 3 mm slice thickness, 2 mm reconstruction increment, B30f standard soft tissue kernel) for either initial staging or therapy monitoring. Corresponding raw data from these standard-dose scans were simulated at lower radiation doses of 80/60/40 mAseff (Somatom Noise Vers.6.1 beta, Siemens Healthcare, Forchheim, Germany). A semi-automated software tool (SyngoCT Oncology, Siemens Healthcare, Forchheim, Germany) was applied to each dose setting to evaluate size parameters (RECIST, volume). These measurements were compared by applying repeated-measures analysis of variance and displayed graphically.
  
  
  RESULTS
  For RECIST measurements no statistically significant differences were found between standard dose (Mean RECIST diameter: 20.46 +/- 8.37 mm) and different simulated low radiation doses (80 mAseff: 20.95 +/- 8.20 mm/60 mAseff: 20.50 +/- 8.35 mm/40 mAseff: 19.95 +/- 8.16 mm): P = 0.0774.Statistically significant differences of volume quantification (P < 0.05) could be found between standard-(3.60 +/- 4.63 mL) and simulated lowest dose of 40 mAseff (3.17 +/- 4.08 mL), whereas there was no difference (P > 0.05) between 160 mAseff- and either 80 mAseff-(3.46 +/- 4.31 mL) or 60 mAseff-protocols (3.44 +/- 4.35 mL).
  
  
  CONCLUSIONS
  Software-assisted assessment of RECIST criteria and volume demonstrated valid performances under different dose-settings in MDCT; therefore, substantial radiation dose reduction could be possible with the use of semi-automated measurements in follow-up studies.
authors.affiliation: Department of Diagnostic Radiology, University Hospital, RWTH Aachen University, Germany. keil@rad.rwth-aachen.de
authors.forename: Sebastian
authors.initials: S
authors.lastname: Keil
authors.forename: Cedric
authors.initials: C
authors.lastname: Plumhans
authors.forename: Istvan A
authors.initials: IA
authors.lastname: Nagy
authors.forename: Katharina
authors.initials: K
authors.lastname: Schiffl
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Soza
authors.forename: Florian F
authors.initials: FF
authors.lastname: Behrendt
authors.forename: Andreas H
authors.initials: AH
authors.lastname: Mahnken
authors.forename: Rolf W
authors.initials: RW
authors.lastname: Günther
authors.forename: Marco
authors.initials: M
authors.lastname: Das
mesh_terms: D000368:Aged; D000465:Algorithms; D001185:Artificial Intelligence; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary*; D008297:Male; D010363:Pattern Recognition, Automated / Q000379:methods*; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*