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Objective To compare four methods of monitoring vascularization of tissue engineered bone in the rhesus so as to find our the best. Methods Twenty-five lower limbs of 13 rhesuses were used in this study to make models of tibial diaphyseal defect of 20mm which were to be fixed with an AO reconstruction plate of 7 holes. The monkeys were randomly divided into five groups according to defect filling materials: group A:?-tricalcium phosphate (?-TCP) and bone marrow stromal cells (BMSCs) and blood vessel bundles; group B:?-TCP and blood vessel bundles; group C:?-TCP and BMSCs; group D:?-TCP; group E: blank. Perfusion weighted MR imaging (PWMR), X-ray, radionuclide imaging and histological examinations were carried out at weeks 4, 8, 12 postop- eratively. The maximum slope rates of the single intensity-time curve (SS_(max)) and values of baseline (Sl_(?))were calculated at the same time points. Transmittances of the X-ray films were assessed. Ratios between isotope counts in region of interest (ROI) were calculated. Chinese ink perfusion and calculation of blood vessel areas were done for histological examinations, Results Compared with other groups, the SS_(max) in group A was the highest at weeks 4, 8, 12 postoperatively. In group A, the SS_(max) at week eight was significantly higher than that at week four (P= 0. 003), and the SS_(max) and transmittance of X-ray were negatively related at week 12 after operation (rs=-0. 892, P=0. 042), but the SS_(max) and blood vessel area were positively related (rs=0. 894, P=0.041)Conclusions PWMR can be a sensitive, quantitative, noninvasive and non-radiant method to monitor vascularization of tissue engineered bone, because SS_(max) of the single intensity-time curve of PWMR can reflect the most accurately the process of vascularization of tissue engineered bone.
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Objective To evaluate the effect of surgical treatment in ischemic cerebrovascular disease using perfusion-weighted magnetic resonance imaging (PWI) technique.Methods The clinical and imaging data of 24 patients with ischemic cerebrovascular disease were analyzed retrospectively. Cerebral perfusion was compared before and after operation by PWI.Results In our series, there were 9 cases of stenosis or occlusion of unilateral internal carotid artery (ICA), 8 cases of unilateral stenosis or occlusion of middle cerebral artery (MCA), 5 cases of multiple stenoses of intra- or extracranial artery system, 2 cases of moyamoya disease. PWI revealed 1 case of normal regional cerebral blood flow (rCBF) and mean transit time (MTT), 15cases of normal rCBF with increased MTT, and 8 cases of decreased rCBF with increased MTT. 23 patients received surgical treatment. There were 13 patients performed by stent angioplasty, 4 patients by endarterectomy, and 6 patients by STA-MCA bypass surgery. Cerebral perfusion improved in 19 cases (82.6%), which included 12 cases (92.3%) performed with stent angioplasty, 4 cases (100%) with endarterectomy and 3 cases (50%) with STA-MCA bypass surgery.Conclusions Being a new type of examination, PWI is helpful to evaluate the status of cerebral perfusion. Surgical methods are effective in treatment of ischemic cerebrovascular disease.