[A method of lung puncture path planning based on multi-level constraint].

Percutaneous pulmonary puncture guided by computed tomography (CT) is one of the most effective tools for obtaining lung tissue and diagnosing lung cancer. Path planning is an important procedure to avoid puncture complications and reduce patient pain and puncture mortality. In this work, a path planning method for lung puncture is proposed based on multi-level constraints. A digital model of the chest is firstly established using patient's CT image. A Fibonacci lattice sampling is secondly conducted on an ideal sphere centered on the tumor lesion in order to obtain a set of candidate paths. Finally, by considering clinical puncture guidelines, an optimal path can be obtained by a proposed multi-level constraint strategy, which is combined with oriented bounding box tree (OBBTree) algorithm and Pareto optimization algorithm. Results of simulation experiments demonstrated the effectiveness of the proposed method, which has good performance for avoiding physical and physiological barriers. Hence, the method could be used as an aid for physicians to select the puncture path.

Pulsed electromagnetic fields attenuate glucocorticoid-induced bone loss by targeting senescent LepR+ bone marrow mesenchymal stromal cells.

Glucocorticoids induce cellular senescence, including of stem/progenitor cells in the bone marrow of growing long bone, which leads to bone loss in glucocorticoid-induced osteoporosis. There is no specific drug available to treat this disease. Clearance of senescent cells has been reported to be an effective therapy for osteoporosis. LepR+ cells in the bone marrow are the key kind of stem/progenitor cells conducive to bone remodeling in adulthood. Here, we show that glucocorticoids induce cellular senescence, demonstrated by increased activity of senescence-associated ß-galactosidase (SA-ßGal+) cells and simultaneous upregulation of coimmunofluorescence staining of p16INK4a with LepR in longitudinal femoral sections. We applied pulsed electromagnetic fields (PEMFs), which alleviated bone loss in glucocorticoid-induced osteoporosis mice. We found the increased accumulation of senescent LepR+ cells in the bone marrow of adult mice after glucocorticoid treatment, and this could be counteracted by PEMFs. Moreover, PEMFs maintained type H vessel formation and osteogenesis. This process was modulated by the polycomb histone methyltransferase enhancer of zeste homolog 2 (EZH2) and its trimethylation of histone H3 on lysine 27 (H3K27me3). These results provide evidence that PEMFs alleviate bone loss induced by glucocorticoids by eliminating senescent cells, maintaining angiogenesis-osteogenesis coupling, and shedding light on the mechanisms, providing a potential method to treat glucocorticoid-induced osteoporosis.

Extraction of pulmonary Trachea by dynamic tubular edge contour algorithm.

BACKGROUND: One of the difficulties and hot topics in the field of computer vision and image processing is extraction of the high-level pulmonary trachea from patients' lung CT images. Current, common bronchial extraction methods are limited by the phenomenon of bronchial loss and leakage, and cannot extract the higher-level pulmonary trachea, which does not meet the requirements of guiding lung puncture procedures. METHODS: Based on the characteristic "tubular structure" (ring or semi-closed ring) of the pulmonary trachea in CT images, an algorithm based on dynamic tubular edge contour is proposed. In axial, coronal and sagittal CT images, the algorithm could extract the skeletal line of the pulmonary trachea and vessel-connecting region, perform elliptical fitting, extract the pulmonary trachea by the ratio of the ellipse's long and short axes, and obtain point cloud data of the pulmonary trachea in three directions. The point cloud data was fused to obtain a complete three-dimensional model of the pulmonary trachea. RESULTS: The algorithm was verified using CT data from "EXACT09", and could extract the pulmonary trachea to the 10-11 level, which effectively solves the problems of leakage and loss of the trachea. CONCLUSIONS: We have constructed a novel extraction algorithm of pulmonary trachea that can guide the doctors to decide the puncture path and avoid the large trachea, which has important theoretical and practical significance for reducing puncture complications and the mortality rate.