MRT letter: Contrast-enhanced computed tomographic imaging of soft callus formation in fracture healing.
Formation of a cartilaginous soft callus at the site of a bone fracture is a pivotal stage in the healing process. Noninvasive, or even nondestructive, imaging of soft callus formation can be an important tool in experimental and pre-clinical studies of fracture repair. However, the low X-ray attenuation of cartilage renders the soft callus nearly invisible in radiographs. This study utilized a recently developed, cationic, iodinated contrast agent in conjunction with micro-computed tomography to identify cartilage in fracture calluses in the femora of C57BL/6J and C3H/HeJ mice. Fracture calluses were scanned before and after incubation in the contrast agent. The set of pre-incubation images was registered against and then subtracted from the set of post-incubation images, resulting in a three-dimensional map of the locations of cartilage in the callus, as labeled by the contrast agent. This map was then compared to histology from a previous study. The results showed that the locations where the contrast agent collected in relatively high concentrations were similar to those of the cartilage. The contrast agent also identified a significant difference between the two strains of mice in the percentage of the callus occupied by cartilage, indicating that this method of contrast-enhanced computed tomography may be an effective technique for nondestructive, early evaluation of fracture healing.
Department of Mechanical Engineering, Boston University, Boston, Massachusetts. lnmh@bu.edu
Lauren Nicole Miller
LN
Hayward
Chantal Marie-Jeanne
CM
de Bakker
Hrvoje
H
Lusic
Louis Charles
LC
Gerstenfeld
Mark W
MW
Grinstaff
Elise Feng-I
EF
Morgan
D000818:Animals; D002146:Bony Callus / Q000000981:diagnostic imaging*; D002356:Cartilage / Q000000981:diagnostic imaging* / Q000503:physiopathology; D017102:Fracture Healing; D050723:Fractures, Bone / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D014057:Tomography, X-Ray Computed / Q000379:methods*