[Perfusion-weighted magnetic resonance imaging for monitoring vascularization in tissue-engineered bone in rhesuses].
OBJECTIVE
To assess the value of perfusion-weighted magnetic resonance (MR) imaging (PWMRI) in monitoring vascularization in tissue-engineered bone graft.


METHODS
Tibial diaphyseal defect of 20 mm was induced in 25 lower limbs of 13 rhesuses and fixed with an AO reconstruction plate with 7 holes. The monkeys were randomized into 5 groups according to the materials used for defect filling: group A, with beta-tricalcium phosphate (beta-TCP), bone marrow stromal cells (BMSCs) and blood vessel bundles; group B, with beta-TCP and blood vessel bundles; group C, with beta-TCP and BMSCs; group D, with beta-TCP, and group E without filling. PWMRI, X-ray, and radionuclide imaging were carried out at weeks 4, 8, 12 postoperatively. The maximum slope rates of the single intensity-time curve (SS(max)) and the baseline values (SI(baseline)) on the same time points were calculated. Transmittances on the X-ray films and isotope counts in the region of interest (ROI) were assessed and calculated.


RESULTS
Compared with other groups, group A showed the highest SS(max) at weeks 4, 8, and 12 postoperatively, and its SS(max) at week 8 was significantly higher than that at week 4 (P=0.003). The SS(max) was positively related to isotope counts in ROI at week 8 after operation (r(s)=0.899, P=0.038), and inversely related to transmittance on X-ray films at week 12 (r(s)=-0.892, P=0.042).


CONCLUSIONS
The SS(max) of the single intensity-time curve can accurately reflect the vascularization of the tissue-engineered bone graft, and PWMRI allows sensitive, quantitative, noninvasive and radiation-free vascularization monitoring.
Wang
Xue-ming
XM
Department of Traumatology and Orthopedics, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China. wxm-8@163.com
Pei
Guo-xian
GX
Jin
Dan
D
Wei
Kuan-hai
KH
Jiang
Shan
S
Tang
Guang-hui
GH
D000818:Animals; D016026:Bone Marrow Transplantation / Q000379:methods*; D018786:Bone Substitutes / Q000737:chemistry / Q000627:therapeutic use; D002130:Calcium Phosphates / Q000627:therapeutic use; D005260:Female; D008253:Macaca mulatta; D018810:Magnetic Resonance Angiography; D008297:Male; D018919:Neovascularization, Physiologic / Q000187:drug effects / Q000502:physiology*; D011897:Random Allocation; D013977:Tibia / Q000098:blood supply / Q000293:injuries / Q000601:surgery*; D023822:Tissue Engineering / Q000379:methods*
D018786:Bone Substitutes; D002130:Calcium Phosphates; C485817:beta-tricalcium phosphate