Temporal Estimation of Non-Rigid Dynamic Human Point Cloud Sequence Using 3D Skeleton-Based Deformation for Compression.

This paper proposes an algorithm for transmitting and reconstructing the estimated point cloud by temporally estimating a dynamic point cloud sequence. When a non-rigid 3D point cloud sequence (PCS) is input, the sequence is divided into groups of point cloud frames (PCFs), and a key PCF is selected. The 3D skeleton is predicted through 3D pose estimation, and the motion of the skeleton is estimated by analyzing the joints and bones of the 3D skeleton. For the deformation of the non-rigid human PC, the 3D PC model is transformed into a mesh model, and the key PCF is rigged using the 3D skeleton. After deforming the key PCF into the target PCF utilizing the motion vector of the estimated skeleton, the residual PC between the motion compensation PCF and the target PCF is generated. If there is a key PCF, the motion vector of the target PCF, and a residual PC, the target PCF can be reconstructed. Just as compression is performed using pixel correlation between frames in a 2D video, this paper compresses 3D PCFs by estimating the non-rigid 3D motion of a 3D object in a 3D PC. The proposed algorithm can be regarded as an extension of the 2D motion estimation of a rigid local region in a 2D plane to the 3D motion estimation of a non-rigid object (human) in 3D space. Experimental results show that the proposed method can successfully compress 3D PC sequences. If it is used together with a PC compression technique such as MPEG PCC (point cloud compression) in the future, a system with high compression efficiency may be configured.

3D Static Point Cloud Registration by Estimating Temporal Human Pose at Multiview.

This paper proposes a new technique for performing 3D static-point cloud registration after calibrating a multi-view RGB-D camera using a 3D (dimensional) joint set. Consistent feature points are required to calibrate a multi-view camera, and accurate feature points are necessary to obtain high-accuracy calibration results. In general, a special tool, such as a chessboard, is used to calibrate a multi-view camera. However, this paper uses joints on a human skeleton as feature points for calibrating a multi-view camera to perform calibration efficiently without special tools. We propose an RGB-D-based calibration algorithm that uses the joint coordinates of the 3D joint set obtained through pose estimation as feature points. Since human body information captured by the multi-view camera may be incomplete, a joint set predicted based on image information obtained through this may be incomplete. After efficiently integrating a plurality of incomplete joint sets into one joint set, multi-view cameras can be calibrated by using the combined joint set to obtain extrinsic matrices. To increase the accuracy of calibration, multiple joint sets are used for optimization through temporal iteration. We prove through experiments that it is possible to calibrate a multi-view camera using a large number of incomplete joint sets.

Comparison of carotid intima-media thickness and coronary artery calcium score for estimating subclinical atherosclerosis in patients with fatty liver disease.

INTRODUCTION: Fatty liver disease (FLD) is correlated with cardiovascular disease. Carotid intima-media thickness (CIMT) and coronary artery calcium score (CACS) can noninvasively identify subclinical atherosclerosis and predict risk for cardiovascular events. This study evaluated CIMT and CACS measurements to detect subclinical atherosclerosis in patients with and without FLD. METHODS: Patients who underwent carotid and abdominal ultrasounds as well as cardiac computed tomography (CT) scans were evaluated retrospectively. The differences between the mean CIMT value and CACS measurements in patients with FLD and those with normal livers were estimated. RESULTS: Among 819 patients (average age of 53.3 ± 11.2 years), 330 had FLD. The CIMT was greater in patients with FLD compared to the controls (0.79 ± 0.17 vs 0.76 ± 0.17 mm, p = 0.012), and carotid plaques were more commonly seen in patients with FLD. The incidence of a composite of larger CIMT ( ≥ 75th percentile) plus plaque presence was higher in FLD patients (43.3 vs 36.0%, p = 0.041). Particularly among young patients (≤ 50), the CIMT was larger in patients with FLD than in the controls. FLD increased the risk of a composite of large CIMT plus plaque presence in young patients (odds ratio 1.92, 95% confidence interval 1.05-3.49, p = 0.034). However, patients with FLD had no greater incidence of CACS of over 100 than the controls. CONCLUSION: CIMT was a better marker of underlying subclinical atherosclerotic risk among patients with FLD than CACS. FLD particularly, increases the risk of subclinical atherosclerosis in patients younger than 50 years of age. These patients should undergo screening CIMT to detect atherosclerosis and modify risk factors.

Right ventricular strain as predictor of pulmonary complications in patients with femur fracture.

BACKGROUND: Following femur fracture, medullary fat enters the systemic circulation and altered pulmonary haemodynamics may contribute to pulmonary complications. This study evaluated the association between right ventricular (RV) function and pulmonary complications in patients with femur fracture. METHODS: Patients with a femur fracture who had undergone pre-operative echocardiography that included RV peak global longitudinal strain (RV GLS) were evaluated retrospectively between March 2015 and February 2016. Pulmonary complications were defined as the development of pneumonia or pulmonary thromboembolism during the first postoperative month. RESULTS: Among 78 patients, pulmonary complications developed in eight (10.3%). The RV GLS value of all patients was lower than the normal range. In addition, the RV GLS value of patients with pulmonary complications was significantly lower than that of patients without pulmonary complications. Multivariate regression analyses found that worse RV GLS values independently predicted pulmonary complications [odds ratio (OR) 2.09, 95% confidence interval (CI) 1.047-4.151, p = 0.037]. Receiver operating characteristic curve analysis found that a RV GLS value of -14.85% was the best cut-off value to predict pulmonary complications; sensitivity: 75.0%; specificity: 62.9%. Moreover, patients with RV GLS values > -14.85% had significantly lower pulmonary complication-free survival. CONCLUSIONS: In patients with femur fracture, RV GLS values could help predict pulmonary complications. Therefore, patients with RV GLS values > -14.85 should be monitored closely before and after surgery for femur fracture.

Gender-based differences in the relationship between fatty liver disease and atherosclerosis.

BACKGROUND: Carotid intima-media thickness (CIMT) is a surrogate of subclinical atherosclerosis. Fatty liver disease is also linked to increased risk of cardiovascular events. The aim of this study was to evaluate the association between fatty liver disease and CIMT according to gender. METHODS: Patients who had undergone carotid and abdominal ultrasound between June 2011 and December 2013 were retrospectively evaluated. The differences between the CIMT values measured in the common carotid artery and the prevalence of carotid plaque in patients with fatty liver disease and those with normal livers were investigated. RESULTS: Out of a total of 1 121 patients, the men had more fatty liver disease than the women. The mean CIMT of the men was significantly higher than that of the women, and the men had more plaque than the women. The women with fatty liver disease had a significantly higher mean CIMT value and more plaque than the women with normal livers. The differences between the men with fatty liver and those with normal livers in mean CIMT values and in the prevalence of plaque were not significant. In the women, multivariate analysis showed that fatty liver disease was independently associated with subclinical atherosclerosis [adjusted hazards ratio (HR) 1.65, 95% confidence interval (CI) 1.007-2.697, p = 0.047]. CONCLUSIONS: The men had more fatty liver disease, carotid plaque and higher CIMT values than the women. Fatty liver disease was a useful predictor of atherosclerosis, especially for the female study patients.

Serial intravascular ultrasound evidence of both plaque stabilization and lesion progression in patients with ruptured coronary plaques: effects of statin therapy on ruptured coronary plaque.

Using serial intravascular ultrasound (IVUS), we evaluated the natural evolution of non-culprit/non-target lesion ruptured coronary plaques and assessed the impact of statin therapy. Twenty-eight patients with non-stenotic ruptured plaques underwent baseline and 12-month follow-up IVUS studies; half were treated with statins. Standard IVUS analyses were performed. Complete healing of ruptured plaques was observed in four (29%) statin-treated patients and no non-statin-treated patients (p=0.049). Statin-treated patients had an increase in lumen area of 0.4+/-0.8 mm2 (versus a decrease in lumen area of -0.6+/-1.0 mm2 in non-statin-treated patients, p=0.007) and no change in plaque area (versus an increase in plaque area of 0.6+/-0.9 mm2, p=0.051). During 1-year follow-up, target lesion revascularization was performed in three non-statin-treated patients (21%) and no statin-treated patient (p=0.11). Compared to lesions that did not require revascularization, lesions requiring revascularization had a decrease in lumen area (-1.7+/-1.4 mm2 versus 0.1+/-0.8 mm2, p=0.001) as well as an increase in plaque area (1.6+/-1.0 mm2 versus 0.1+/-0.7 mm2, p=0.002). In conclusion, the current observational follow-up IVUS study showed beneficial effects of statin treatment on reduction of revascularization rates and stabilization of non-culprit/non-target lesion plaque ruptures without significant stenosis. Conversely, healing of non-statin-treated non-culprit/non-target lesion plaque ruptures can be responsible for lesion progression requiring revascularization.