title: Thoracic Temporal Subtraction Three Dimensional Computed Tomography (3D-CT): Screening for Vertebral Metastases of Primary Lung Cancers.
abstract: OBJECTIVE
  We developed an original, computer-aided diagnosis (CAD) software that subtracts the initial thoracic vertebral three-dimensional computed tomography (3D-CT) image from the follow-up 3D-CT image. The aim of this study was to investigate the efficacy of this CAD software during screening for vertebral metastases on follow-up CT images of primary lung cancer patients.
  
  
  METHODS
  The interpretation experiment included 30 sets of follow-up CT scans in primary lung cancer patients and was performed by two readers (readers A and B), who each had 2.5 years' experience reading CT images. In 395 vertebrae from C6 to L3, 46 vertebral metastases were identified as follows: osteolytic metastases (n = 17), osteoblastic metastases (n = 14), combined osteolytic and osteoblastic metastases (n = 6), and pathological fractures (n = 9). Thirty-six lesions were in the anterior component (vertebral body), and 10 lesions were in the posterior component (vertebral arch, transverse process, and spinous process). The area under the curve (AUC) by receiver operating characteristic (ROC) curve analysis and the sensitivity and specificity for detecting vertebral metastases were compared with and without CAD for each observer.
  
  
  RESULTS
  Reader A detected 47 abnormalities on CT images without CAD, and 33 of them were true-positive metastatic lesions. Using CAD, reader A detected 57 abnormalities, and 38 were true positives. The sensitivity increased from 0.717 to 0.826, and on ROC curve analysis, AUC with CAD was significantly higher than that without CAD (0.849 vs. 0.902, p = 0.021). Reader B detected 40 abnormalities on CT images without CAD, and 36 of them were true-positive metastatic lesions. Using CAD, reader B detected 44 abnormalities, and 39 were true positives. The sensitivity increased from 0.783 to 0.848, and AUC with CAD was nonsignificantly higher than that without CAD (0.889 vs. 0.910, p = 0.341). Both readers detected more osteolytic and osteoblastic metastases with CAD than without CAD.
  
  
  CONCLUSIONS
  Our temporal 3D-CT subtraction CAD software easily detected vertebral metastases on the follow-up CT images of lung cancer patients regardless of the osteolytic or osteoblastic nature of the lesions.
authors.affiliation: Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Iwano
authors.affiliation: Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
authors.forename: Rintaro
authors.initials: R
authors.lastname: Ito
authors.affiliation: Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Umakoshi
authors.affiliation: Imaging Technology Center, Fujifilm Corporation, Tokyo, Japan.
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Karino
authors.affiliation: Imaging Technology Center, Fujifilm Corporation, Tokyo, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Inoue
authors.affiliation: Imaging Technology Center, Fujifilm Corporation, Tokyo, Japan.
authors.forename: Yuanzhong
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Naganawa
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001859:Bone Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary*; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D011857:Radiographic Image Interpretation, Computer-Assisted; D013902:Radiography, Thoracic / Q000379:methods*; D012189:Retrospective Studies; D055752:Small Cell Lung Carcinoma / Q000000981:diagnostic imaging / Q000473:pathology; D012984:Software; D014057:Tomography, X-Ray Computed / Q000379:methods*