title: Computerized delineation of nuclei in liquid-based pap smears stained with immunohistochemical biomarkers.
abstract: BACKGROUND
  Infection with high-risk human papillomaviruses (hrHPVs) is a frequent cause of cervical intraepithelial neoplasias and carcinomas. The recently developed p16/Ki67 dual stain of cytologic preparations possesses superior specificity over current HPV testing for detecting moderate- and high-grade dysplasias and can potentially be applied in routine cytology screening. Image analysis can possibly improve the efficiency of evaluating Papanicolaou (Pap) smears, if dual-stained nuclei are accurately localized and reliably distinguished from the background of other cells.
  
  
  METHODS
  Here, we describe a technique comprising color deconvolution, radial symmetry detector, and a superpixel-based segmentation for computerized delineation of nuclei in Pap smears stained with p16/Ki67.
  
  
  RESULTS
  The performance of the method was determined by the precision and recall in 99 images (n = 19,323 cells) and reached 0.952 and 0.958, respectively. The accuracy of delineation, assessed by the Jaccard index (n = 1,080 cells), was 0.794. In single cells the precision and recall was higher than in clumps (P = 0.005).
  
  
  CONCLUSIONS
  In summary, the new technique delineates large and small nuclei irrespectively of coloration with a significantly better performance than a method solely involving the radial symmetry detector. Therefore, it is suited to automatically define nuclear areas for quantification of nuclear biomarkers in smears.
authors.affiliation: Bioimage Informatics Laboratory, Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, California.
authors.forename: Yi
authors.initials: Y
authors.lastname: Qin
authors.forename: Ann E
authors.initials: AE
authors.lastname: Walts
authors.forename: Beatrice S
authors.initials: BS
authors.lastname: Knudsen
authors.forename: Arkadiusz
authors.initials: A
authors.lastname: Gertych
mesh_terms: D015415:Biomarkers / Q000032:analysis / Q000737:chemistry; D002467:Cell Nucleus / Q000737:chemistry* / Q000276:immunology*; D003581:Cytodiagnosis / Q000379:methods / Q000592:standards; D003936:Diagnosis, Computer-Assisted / Q000379:methods / Q000592:standards*; D005260:Female; D006801:Humans; D014626:Vaginal Smears / Q000379:methods / Q000592:standards*
chemical_list: D015415:Biomarkers
keywords: Pap test; biomarkers; image analysis; immunohistochemistry; nuclei segmentation; p16/Ki67