Effect of intertrochanteric osteotomy on the proximal femur of rabbits: assessment with power Doppler sonography and scintigraphy.
OBJECTIVE
In bone injury, repair results in local increased vascularity and bone marrow remodeling. Characterizing the vascular and metabolic imaging patterns of the proximal femur following an intertrochanteric osteotomy may help clinicians decide proper management of the patient. Our objective was to measure Doppler sonography and scintigraphy interval changes in the proximal femur following intertrochanteric osteotomy and compare imaging and histomorphometric measurements in the late post-operative stage (6 weeks after surgery) in a rabbit model of bone injury.


METHODS
Both hips of 12 adult rabbits were imaged with power Doppler sonography and scintigraphy prior to and after (7 days and 6 weeks) unilateral osteotomy. Accuracy of the imaging methods was evaluated using hip operative status and histomorphometric results (vascular fractional area and number of vessels per area unit) as reference standard measures.


RESULTS
A significant difference in the mean number of pixels was noted between operated and non-operated femura in late post-operative power Doppler examinations (P=0.049). Although without reaching statistical significance, the AUC of Doppler measurements (AUC=0.99) was numerically greater than the AUC of scintigraphy measurements (AUC=0.857+/-0.099) (P=0.15) in differentiating proximal femura with regard to their fractional vascular areas in the late post-operative stage. In contrast, scintigraphy tended to perform better (AUC=0.984+/-0.022) than Doppler ultrasound (AUC=0.746+/-0.131) to demonstrate the vascularity intensity per area unit (P=0.07) in the late stage.


CONCLUSIONS
Our results warrant further investigation to determine the value of different imaging modalities for assessment of pathologic changes following hip surgery. Power Doppler sonography demonstrated larger AUCs (representing higher accuracy) for the discrimination of vascular fractional areas and scintigraphy, for discrimination of the number of vessels per area unit.
Doria
Andrea S
AS
Department of Diagnostic Imaging, Hospital for Sick Children, University of Toronto, Canada. andrea.doria@sickkids.ca
Cunha
Fabiano G
FG
Modena
Marcelo
M
Rodrigues
Consuelo Junqueira
CJ
Garcez
Alexandre Teles
AT
Godoy Junior
Rui de
Rd
Bolliger Neto
Raul
R
Melo
Ivani Bortoleti
IB
Buchpiguel
Carlos
C
Molnar
Laszlo J
LJ
Guarniero
Roberto
R
D000818:Animals; D001847:Bone Diseases / Q000000981:diagnostic imaging*; D016723:Bone Remodeling / Q000502:physiology; D004195:Disease Models, Animal; D004839:Epiphyses, Slipped / Q000000981:diagnostic imaging; D005269:Femur / Q000000981:diagnostic imaging; D006621:Hip Joint / Q000000981:diagnostic imaging; D007873:Legg-Calve-Perthes Disease / Q000000981:diagnostic imaging; D010027:Osteotomy / Q000379:methods*; D011184:Postoperative Period; D011817:Rabbits; D011877:Radionuclide Imaging; D018608:Ultrasonography, Doppler / Q000379:methods