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MRI in the assessment of growth arrest
Martina Lohman1, Arto Kivisaari, Tapio Vehmas
1Department of Radiology, Helsinki University Central Hospitall, Finland. martina.lohman@hus.fi
Objective:
To compare MRI with X-ray tomography in the assessment of bone bridges across the growth plate.
Materials And Methods:
The investigation consisted of two parts. (1) Eleven children with 13 epiphyses suspected of physeal growth arrests were examined with conventional X-ray tomography and MRI. The bar was post-traumatic in eight children, postinfectious in two and due to a congenital, operated pes equinovarus in one. Three blinded radiologists separately evaluated the examinations retrospectively. (2) The images of four children with known physeal bars in the ankle were mixed with 36 normal examinations obtained 1-year after trauma and evaluated blindly by three radiologists.
Results:
In 5 of 13 epiphysis, the bony bridge was considered smaller on MRI than on X-ray tomography, in 7 of 13 it was considered equal, while it was larger only in one. The interobserver agreement (weighted kappa) was 0.8 (very good) for MRI, 0.76 (good) for X-ray tomography and 0.60 (moderate) for radiographs. The four bony bridges were easily detected on MRI.
Conclusions:
Compared to MRI, the size of bridges was estimated larger by tomography in about half of the patients.