Pediatric Radiology

, Volume 42, Issue 11, pp 1364–1371 | Cite as

The trochlear pre-ossification center: a normal developmental stage and potential pitfall on MR images

  • Camilo Jaimes
  • Mauricio Jimenez
  • Diana Marin
  • Victor Ho-Fung
  • Diego JaramilloEmail author
Original Article



The hypertrophic changes that occur in the cartilage of an epiphysis prior to the onset of ossification are known as the pre-ossification center. Awareness of the appearance of the pre-ossification center on MR images is important to avoid confusing normal developmental changes with pathology.


The purpose of this study was to determine the characteristics of the trochlear pre-ossification center on MR imaging and examine age and gender differences.

Materials and methods

We retrospectively analyzed MR images from 61 children. The trochleas were categorized into three types on the basis of signal intensity (SI). Trochlear types were compared to age and gender.


There was no significant difference between the ages of boys and girls. Type 1 trochleas showed homogeneous SI on all pulse sequences. Type 2 trochleas demonstrated a focus of high SI in the epiphyseal cartilage on fat-suppressed water-sensitive sequences, with high or intermediate SI on gradient-echo images (pre-ossification center). Type 3 trochleas showed low SI on fat-suppressed water-sensitive sequences and gradient-echo images. Thirty-seven trochleas were described as type 1, sixteen as type 2 and eight as type 3. ANOVAs confirmed a statistically significant difference in the age of children with type 3 trochleas and those with types 1 and 2 (P < 0.001). Spearman rank correlations determined a positive relationship between trochlear type and age of the children (r = 0.53).


Development-related changes in the trochlea follow a predictable pattern. The signal characteristics of the pre-ossification center likely reflect normal chondrocyte hypertrophy and an increase in free water in the matrix.


Elbow MRI Ossification Children Skeletal maturation Pre-ossification center 


Conflict of interest

We have no conflicts of interest to declare.


  1. 1.
    Emery KH (2009) MR imaging in congenital and acquired disorders of the pediatric upper extremity. Magn Reson Imaging Clin N Am 17:549–570, viiPubMedCrossRefGoogle Scholar
  2. 2.
    Chapman VM, Nimkin K, Jaramillo D (2004) The pre-ossification center: normal CT and MRI findings in the trochlea. Skeletal Radiol 33:725–727PubMedCrossRefGoogle Scholar
  3. 3.
    Patel B, Reed M, Patel S (2009) Gender-specific pattern differences of the ossification centers in the pediatric elbow. Pediatr Radiol 39:226–231PubMedCrossRefGoogle Scholar
  4. 4.
    Landis JR, Koch GG (1977) The measurement of observer agreement for categorical data. Biometrics 33:159–174PubMedCrossRefGoogle Scholar
  5. 5.
    Jaramillo D, Waters PM (1997) MR imaging of the normal developmental anatomy of the elbow. Magn Reson Imaging Clin N Am 5:501–513PubMedGoogle Scholar
  6. 6.
    Yamaguchi K, Sweet FA, Bindra R et al (1997) The extraosseous and intraosseous arterial anatomy of the adult elbow. J Bone Joint Surg Am 79:1653–1662PubMedGoogle Scholar
  7. 7.
    Rivas R, Shapiro F (2002) Structural stages in the development of the long bones and epiphyses: a study in the New Zealand white rabbit. J Bone Joint Surg Am 84-A:85–100PubMedGoogle Scholar
  8. 8.
    Laor T, Jaramillo D (2009) MR imaging insights into skeletal maturation: what is normal? Radiology 250:28–38PubMedCrossRefGoogle Scholar
  9. 9.
    Jaramillo D, Villegas-Medina OL, Doty DK et al (2004) Age-related vascular changes in the epiphysis, physis, and metaphysis: normal findings on gadolinium-enhanced MRI of piglets. AJR 182:353–360PubMedGoogle Scholar
  10. 10.
    Jaramillo D (2008) Cartilage imaging. Pediatr Radiol 38(Suppl 2):S256–S258PubMedCrossRefGoogle Scholar
  11. 11.
    Babyn PS, Kim HK, Lemaire C et al (1996) High-resolution magnetic resonance imaging of normal porcine cartilaginous epiphyseal maturation. J Magn Reson Imaging 6:172–179PubMedCrossRefGoogle Scholar
  12. 12.
    Oeppen RS, Connolly SA, Bencardino JT et al (2004) Acute injury of the articular cartilage and subchondral bone: a common but unrecognized lesion in the immature knee. AJR 182:111–117PubMedGoogle Scholar
  13. 13.
    Kendell SD, Helms CA, Rampton JW et al (2005) MRI appearance of chondral delamination injuries of the knee. AJR 184:1486–1489PubMedGoogle Scholar
  14. 14.
    Khanna PC, Thapa MM (2009) The growing skeleton: MR imaging appearances of developing cartilage. Magn Reson Imaging Clin N Am 17:411–421, vPubMedCrossRefGoogle Scholar
  15. 15.
    Bydder M, Rahal A, Fullerton GD et al (2007) The magic angle effect: a source of artifact, determinant of image contrast, and technique for imaging. J Magn Reson Imaging 25:290–300PubMedCrossRefGoogle Scholar
  16. 16.
    Wacker FK, Bolze X, Felsenberg D et al (1998) Orientation-dependent changes in MR signal intensity of articular cartilage: a manifestation of the ‘magic angle’ effect. Skeletal Radiol 27:306–310PubMedCrossRefGoogle Scholar
  17. 17.
    Varich LJ, Laor T, Jaramillo D (2000) Normal maturation of the distal femoral epiphyseal cartilage: age-related changes at MR imaging. Radiology 214:705–709PubMedGoogle Scholar
  18. 18.
    Leonard MB, Elmi A, Mostoufi–Moab S et al (2010) Effects of sex, race, and puberty on cortical bone and the functional muscle bone unit in children, adolescents, and young adults. J Clin Endocrinol Metab 95:1681–1689PubMedCrossRefGoogle Scholar
  19. 19.
    Jans LB, Jaremko JL, Ditchfield M et al (2011) Evolution of femoral condylar ossification at MR imaging: frequency and patient age distribution. Radiology 258:880–888PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • Camilo Jaimes
    • 1
  • Mauricio Jimenez
    • 3
  • Diana Marin
    • 4
  • Victor Ho-Fung
    • 1
    • 2
  • Diego Jaramillo
    • 1
    • 2
    Email author
  1. 1.Department of RadiologyThe Children’s Hospital of PhiladelphiaPhiladelphiaUSA
  2. 2.Perelman School of MedicineUniversity of PennsylvaniaPhiladelphiaUSA
  3. 3.Department of RadiologyHospital of the University of PennsylvaniaPhiladelphiaUSA
  4. 4.Department of RadiologyMiami Children’s HospitalMiamiUSA

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