title: Expert System for Bone Scan Interpretation Improves Progression Assessment in Bone Metastatic Prostate Cancer.
abstract: The bone scan index (BSI) was introduced as a quantitative tool for tumor involvement in bone of patients with metastatic prostate cancer (mPCa). The computer-aided diagnosis device for BSI analysis EXINIboneBSIseems to represent technical progress for the quantitative assessment of bone involvement. But it is not yet clear if the automated BSI (aBSI) could contribute to improved evaluation of progression in patients under antiandrogens or chemotherapy in contrast to the visual interpretation and/or conventional biomarkers such as the prostate-specific antigen (PSA).
  
  
  
  In 49 mPCa patients, bone scans were performed initially and during different therapy courses. Scans were evaluated visually and by the artificial-neural-network-based expert system EXINIboneBSI. Progression of metastatic bone involvement was defined according to the Prostate Cancer Clinical Trials Working Group 2 (PCWG2) criteria in the visual interpretation. The computer-assisted interpretation was based on different cutoff values in relative changes of the aBSI. Additionally, assessments according to bone scanning were compared to changes in the PSA value as a potential surrogate for treatment response.
  
  
  
  Using a sensitive cutoff value (5% or 10%) for the relative aBSI increase led to significantly increased progression determination compared to the visual interpretation of bone scans (49% and 43% vs. 27%, p < 0.001). In 63% of the cases PSA and BSI changes matched, whereas in 18% progression was only indicated by the aBSI. A relative cutoff of 5% for the aBSI decrease could reclassify 47 serial scan pairs which were visually interpreted as stable into 22 progressive and 25 remissive scans.
  
  
  
  Distinct thresholds of the relative aBSI could help to better assess disease progression in mPCa patients. Manual corrections of the BSI values are not required in most cases. The aBSI could serve as a useful additional parameter for therapy monitoring in mPCa patients in the future.
authors.affiliation: Department of Nuclear Medicine, Hannover Medical School, Hannover, Germany. Fabian.Haupt@insel.ch.|Department of Nuclear Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland. Fabian.Haupt@insel.ch.
authors.forename: Fabian
authors.identifier: 0000-0002-2401-922X
authors.initials: F
authors.lastname: Haupt
authors.affiliation: Department of Nuclear Medicine, Hannover Medical School, Hannover, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Berding
authors.affiliation: Department of Nuclear Medicine, Hannover Medical School, Hannover, Germany.
authors.forename: Ali
authors.initials: A
authors.lastname: Namazian
authors.affiliation: Department of Medical Physics and Radiation Protection, Hannover Medical School, Hannover, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Wilke
authors.affiliation: Department of Urology and Urologic Oncology, Hannover Medical School, Hannover, Germany.
authors.forename: Alena
authors.initials: A
authors.lastname: Böker
authors.affiliation: Department of Urology, University Lübeck, Lübeck, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Merseburger
authors.affiliation: Department of Medical Physics and Radiation Protection, Hannover Medical School, Hannover, Germany.
authors.forename: Lilli
authors.initials: L
authors.lastname: Geworski
authors.affiliation: Department of Urology and Urologic Oncology, Hannover Medical School, Hannover, Germany.
authors.forename: Markus Antonius
authors.initials: MA
authors.lastname: Kuczyk
authors.affiliation: Department of Nuclear Medicine, Hannover Medical School, Hannover, Germany.
authors.forename: Frank Michael
authors.initials: FM
authors.lastname: Bengel
authors.affiliation: Department of Urology and Urologic Oncology, Hannover Medical School, Hannover, Germany.
authors.forename: Inga
authors.initials: I
authors.lastname: Peters
mesh_terms: D000368:Aged; D001859:Bone Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary*; D018450:Disease Progression; D005103:Expert Systems; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011471:Prostatic Neoplasms / Q000473:pathology*; D011877:Radionuclide Imaging; D012189:Retrospective Studies
keywords: Bone scan index (BSI); Bone scintigraphy; CRPC; Computer-aided diagnosis device; Metastatic prostate cancer; Therapy response