title: Semiautomatic volumetric tumor segmentation for hepatocellular carcinoma: comparison between C-arm cone beam computed tomography and MRI.
abstract: OBJECTIVE
  To evaluate the precision and reproducibility of a semiautomatic tumor segmentation software in measuring tumor volume of hepatocellular carcinoma (HCC) before the first transarterial chemo-embolization (TACE) on contrast-enhancement magnetic resonance imaging (CE-MRI) and intraprocedural dual-phase C-arm cone beam computed tomography (DP-CBCT) images.
  
  
  METHODS
  Nineteen HCCs were targeted in 19 patients (one per patient) who underwent baseline diagnostic CE-MRI and an intraprocedural DP-CBCT. The images were obtained from CE-MRI (arterial phase of an intravenous contrast medium injection) and DP-CBCT (delayed phase of an intra-arterial contrast medium injection) before the actual embolization. Three readers measured tumor volumes using a semiautomatic three-dimensional volumetric segmentation software that used a region-growing method employing non-Euclidean radial basis functions. Segmentation time and spatial position were recorded. The tumor volume measurements between image sets were compared using linear regression and Student's t-test, and evaluated with intraclass-correlation analysis (ICC). The inter-rater Dice similarity coefficient (DSC) assessed the segmentation spatial localization.
  
  
  RESULTS
  All 19 HCCs were analyzed. On CE-MRI and DP-CBCT examinations, respectively, 1) the mean segmented tumor volumes were 87 ± 8 cm(3) (2-873) and 92 ± 10 cm(3) (1-954), with no statistical difference of segmented volumes by readers of each tumor between the two imaging modalities and the mean time required for segmentation was 66 ± 45 seconds (21-173) and 85 ± 34 seconds (17-214) (P = .19); 2) the ICCs were 0.99 and 0.974, showing a strong correlation among readers; and 3) the inter-rater DSCs showed a good to excellent inter-user agreement on the spatial localization of the tumor segmentation (0.70 ± 0.07 and 0.74 ± 0.05, P = .07).
  
  
  CONCLUSIONS
  This study shows a strong correlation, a high precision, and excellent reproducibility of semiautomatic tumor segmentation software in measuring tumor volume on CE-MRI and DP-CBCT images. The use of the segmentation software on DP-CBCT and CE-MRI can be a valuable and highly accurate tool to measure the volume of hepatic tumors.
authors.affiliation: Russell H. Morgan Department of Radiology and Radiological Science, Division of Vascular and Interventional Radiology, Sheikh Zayed Tower, Suite 7203, The Johns Hopkins Hospital, 1800 Orleans Street, Baltimore, MD 21287, USA.
authors.forename: Vania
authors.initials: V
authors.lastname: Tacher
authors.forename: MingDe
authors.initials: M
authors.lastname: Lin
authors.forename: Michael
authors.initials: M
authors.lastname: Chao
authors.forename: Lars
authors.initials: L
authors.lastname: Gjesteby
authors.forename: Nikhil
authors.initials: N
authors.lastname: Bhagat
authors.forename: Abdelkader
authors.initials: A
authors.lastname: Mahammedi
authors.forename: Roberto
authors.initials: R
authors.lastname: Ardon
authors.forename: Benoit
authors.initials: B
authors.lastname: Mory
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Geschwind
mesh_terms: D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging / Q000473:pathology*; D054893:Cone-Beam Computed Tomography; D003287:Contrast Media; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012984:Software; D047368:Tumor Burden
chemical_list: D003287:Contrast Media