Complete three-dimensional (3D) tooth model provides essential information to assist orthodontists for diagnosis and treatment planning. Currently, 3D tooth model is mainly obtained by segmentation and reconstruction from dental computed tomography (CT) images. However, the accuracy of 3D tooth model reconstructed from dental CT images is low and not applicable for invisalign design. And another serious problem also occurs,i.e. frequentative dental CT scan during different intervals of orthodontic treatment often leads to radiation to the patients. Hence, this paper proposed a method to reconstruct tooth model based on fusion of dental CT images and laser-scanned images. A complete 3D tooth model was reconstructed with the registration and fusion between the root reconstructed from dental CT images and the crown reconstructed from laser-scanned images. The crown of the complete 3D tooth model reconstructed with the proposed method has higher accuracy. Moreover, in order to reconstruct complete 3D tooth model of each orthodontic treatment interval, only one pre-treatment CT scan is needed and in the orthodontic treatment process only the laser-scan is required. Therefore, radiation to the patients can be reduced significantly.
Ultrasound guided percutaneous interventional therapy has been widely used in clinic. Aiming at the problem of soft tissue deformation caused by probe contact force in robot-assisted ultrasound-guided therapy, a real-time non-reference ultrasound image evaluation method considering soft tissue deformation is proposed. On the basis of ultrasound image brightness and sharpness, a multi-dimensional ultrasound image evaluation index was designed, which incorporated the aggregation characteristics of the organization. In order to verify the effectiveness of the proposed method, ultrasound images of four different models were collected for experiments, including prostate phantom, phantom with cyst, pig liver tissue, and pig liver tissue with cyst. In addition, the correlation between subjective and objective evaluations was analyzed based on Spearman’s rank correlation coefficient. Experimental results showed that the average evaluation time of a single image was 68.8 milliseconds. The evaluation time could satisfy real-time applications. The proposed method realizes the effective evaluation of real-time ultrasound image quality in robot-assisted therapy, and has good consistency with the evaluation of supervisors.
Objective To ananlyze the relationship between bone mineral density and sex hormone in male patients with obstructive sleep apnea hypopnea syndrome (OSAHS). Methods The study recruited 88 male patients with OSAHS aged 45-60 years in our hospital from October 2014 to October 2016 as an OSAHS group, and 30 healthy subjects without OSAHS as a control group. The general information and PSG parameters were recorded, the bone metabolic markers and bone mineral density of lumbar spine 1-4 (L1-4) and femoral neck (Neck) were measured, and the expressions of serum sex hormone (E2, P, T, FSH, LH and PRL) were determined by chemical luminescence immunity analyzer. The differences in above indexes between two groups and their correlation with bone mineral density were analyzed. Results Smoking rate, drinking rate, neck circumference and body mass index (BMI) of the OSAHS group were significantly higher than those of the control group. Compared with the control group, beta crosslaps (β-CTX, a bone metabolic marker) was significantly higher [(0.53±0.14) ng/ml vs. (0.47±0.15) ng/ml], the bone mineral density of L1-4 and Neck was significantly lower [(0.92±0.12) g/cm2 vs. (1.08±0.08) g/cm2, (0.91±0.11) g/cm2 vs. (1.06±0.13) g/cm2], and the serum testosterone was significantly lower in the OSAHS group [(267.32±89.56) ng/dlvs. (315.68±78.49) ng/dl] (all P<0.05). The result of Pearson correlation analysis showed that apnea hypopnea index (AHI) was negatively correlated with bone mineral density of L1-4 and Neck (bothP<0.001), lowest oxygen saturation (LSaO2) and testosterone were positively correlated with bone mineral density of L1-4 and Neck (all P<0.01). Conclusions The risk of suffering from osteoporosis is higher in male OSAHS patients and it is closely related to the degree of hypoxia. The decrease of testosterone may be one of the mechanisms.