Cerebral hemorrhage is a serious cerebrovascular disease with high morbidity and high mortality, for which timely diagnosis and treatment are crucial. Electrical impedance tomography (EIT) is a functional imaging technique which is able to detect abnormal changes of electrical property of the brain tissue at the early stage of the disease. However, irregular multi-layer structure and different conductivity properties of each layer affect image reconstruction of the brain EIT, resulting in low reconstruction quality. To solve this problem, an image reconstruction method based on an improved densely-connected fully convolutional neural network is proposed in this paper. On the basis of constructing a three-layer cerebral model that approximates the real structure of the human head, the nonlinear mapping between the boundary voltage and the conductivity change is determined by network training, which avoids the error caused by the traditional sensitivity matrix method used for solving inverse problem. The proposed method is also evaluated under the conditions with or without noise, as well as with brain model change. The numerical simulation and phantom experimental results show that conductivity distribution of cerebral hemorrhage can be accurately reconstructed with the proposed method, providing a reliable basis for the diagnosis and treatment of cerebral hemorrhage. Also, it promotes the application of EIT in the diagnosis of brain diseases.
Humans ; Cerebral Hemorrhage/diagnostic imaging* ; Neural Networks, Computer ; Electric Impedance ; Image Processing, Computer-Assisted/methods* ; Tomography/methods* ; Brain/diagnostic imaging* ; Phantoms, Imaging ; Convolutional Neural Networks

OBJECTIVEWe ascertained the effect of bone morphogenetic protein-2 (BMP-2) and basic fibroblast growth factor (bFGF) by a series of experiments: Proliferation and differentiation of bone marrow stromal cells (BMSCs) in vitro, ectopic and in situ bone formation and loaded porous calcium phosphate cement (CPC) on the repair of bone defects around dental implants.

METHODSBMSCs from Beagle dogs were cultured in vitro with basic culture medium containing BMP-2, bFGF, and BMP-2+bFGF. Proliferation and differentiation of BMSCs were quantified using methyl thiazolyl tetrazolium (MTT) and alkaline phosphatase (ALP) test. The CPC seeded with BMSCs and BMP-2, bFGF, combined BMP-2 with bFGF were implanted subcutaneously into nude rats in ectopic bone formation, and were implanted into critical-sized bone defects of Beagle dogs in the in situ bone formation. The bone formation was detected by histology examination and quantified using an image analysis system. Polychrome sequential fluorescent labels and fluorescence histological examinations of undecalcified sections were performed post-operatively.

RESULTSIt was determined that BMP-2+bFGF promoted BMSCs statistically significant proliferation and differentiation compared to either BMP-2 or bFGF in vitro. The CPC with BMP-2+bFGF group yielded more bone than those with either BMP-2 or bFGF in ectopic bone formation test. The percentages of newly ectopic formed bone were higher in the BMP-2+bFGF group (48.79% +/- 11.31%) than those in other groups (BMP-2 group, 30.71% +/- 10.85%; bFGF group, 27.33% +/- 9.67%; and the control group, 10.65% +/- 6.05%). Undecalcified showed that new bone was actively formed in the BMP-2+bFGF group after 12 weeks in the in situ bone formation test. The bone mineralization apposition rate (MAR) was better in the BMP-2+bFGF group than in other groups (P<0.01).

CONCLUSIONBMP-2 combined with bFGF are more effective than one alone in promoting the formation of new bone.

Animals ; Bone Marrow Cells ; Bone Morphogenetic Protein 2 ; Bone and Bones ; Calcium Phosphates ; Cell Differentiation ; Cells, Cultured ; Dogs ; Fibroblast Growth Factor 2 ; Mesenchymal Stromal Cells ; Rats