title: Does overgrowth of costal cartilage cause pectus carinatum? A three-dimensional computed tomography evaluation of rib length and costal cartilage length in patients with asymmetric pectus carinatum.
abstract: OBJECTIVE
  To evaluate whether the overgrowth of costal cartilage may cause pectus carinatum using three-dimensional (3D) computed tomography (CT).
  
  
  METHODS
  Twenty-two patients with asymmetric pectus carinatum were included. The fourth, fifth and sixth ribs and costal cartilages were semi-automatically traced, and their full lengths were measured on three-dimensional CT images using curved multi-planar reformatted (MPR) techniques. The rib length and costal cartilage length, the total combined length of the rib and costal cartilage and the ratio of the cartilage and rib lengths (C/R ratio) in each patient were compared between the protruding side and the opposite side at the levels of the fourth, fifth and sixth ribs.
  
  
  RESULTS
  The length of the costal cartilage was not different between the more protruded side and the contralateral side (55.8 ± 9.8 mm vs 55.9 ± 9.3 mm at the fourth, 70 ± 10.8 mm vs 71.6 ± 10.8 mm at the fifth and 97.8 ± 13.2 mm vs 99.8 ± 15.5 mm at the sixth; P > 0.05). There were also no significant differences between the lengths of ribs. (265.8 ± 34.9 mm vs 266.3 ± 32.9 mm at the fourth, 279.7 ± 32.7 mm vs 280.6 ± 32.4 mm at the fifth and 283.8 ± 33.9 mm vs 283.9 ± 32.3 mm at the sixth; P > 0.05). There was no statistically significant difference in either the total length of rib and costal cartilage or the C/R ratio according to side of the chest (P > 0.05).
  
  
  CONCLUSIONS
  In patients with asymmetric pectus carinatum, the lengths of the fourth, fifth and sixth costal cartilage on the more protruded side were not different from those on the contralateral side. These findings suggest that overgrowth of costal cartilage cannot explain the asymmetric protrusion of anterior chest wall and may not be the main cause of pectus carinatum.
authors.affiliation: Department of Radiology, Research Institute of Radiological Science, Yonsei University Health System, Seoul, Republic of Korea.
authors.forename: Chul Hwan
authors.initials: CH
authors.lastname: Park
authors.forename: Tae Hoon
authors.initials: TH
authors.lastname: Kim
authors.forename: Seok Jin
authors.initials: SJ
authors.lastname: Haam
authors.forename: Sungsoo
authors.initials: S
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D001848:Bone Diseases, Developmental / Q000000981:diagnostic imaging / Q000209:etiology*; D002356:Cartilage / Q000002:abnormalities* / Q000000981:diagnostic imaging*; D002648:Child; D002675:Child, Preschool; D006801:Humans; D021621:Imaging, Three-Dimensional; D009139:Musculoskeletal Abnormalities / Q000000981:diagnostic imaging / Q000209:etiology*; D011237:Predictive Value of Tests; D011857:Radiographic Image Interpretation, Computer-Assisted; D012272:Ribs / Q000002:abnormalities* / Q000000981:diagnostic imaging*; D012307:Risk Factors; D013249:Sternum / Q000002:abnormalities* / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed
keywords: Costal cartilage; Pectus carinatum; Rib; Three-dimensional computed tomography