Journal of Medical and Biological Engineering最新文献

Purpose

Most pulmonary nodule classification methods solely rely on nodule images without considering the corresponding attribute information. Additionally, conventional convolutional structures often fail to capture the relative spatial relationships among different parts of the lung nodule.

Methods

This paper proposes a pulmonary nodule classification method based on attribute privilege and capsule networks. In this approach, eight attribute characteristics of pulmonary nodules are utilized as privileged information during the identification of benign and malignant cases. This additional information empowers the network to distinguish between benign and malignant aspects of pulmonary nodules more accurately. The capsule structure is introduced to help extract and understand the spatial relationships between different parts of the lung nodule images, the Res2net structure is adopted to extract multi-scale information from lung nodules, and an attention mechanism is incorporated into the backbone network to enhance the efficiency of feature extraction. The proposed classification method was thoroughly evaluated through a series of experiments using the LIDC-IDRI dataset.

Results

The mean identification accuracy of pulmonary nodules reaches 91.6%. This outcome demonstrates that the proposed method is capable of identifying benign and malignant pulmonary nodules with high accuracy.

Conclusion

The novel lung nodule recognition method based on attribute privilege and capsule network contributes to achieving better feature extraction and addressing the challenge of small training datasets for pulmonary nodules.

Abstract

Purpose

This study aimed to compare carbon fiber-reinforced polyetheretherketone (CFR-PEEK) plates and screws with conventional titanium plates and screws for mandibular orthognathic surgery models.

Methods

Sagittal split ramus osteotomy (SSRO) was simulated in a 3D finite element model of the mandible. Eight fixation groups with 3 different designs (miniplate, hybrid, and inverted-L) were created using titanium and CFR-PEEK materials. The displacement values in the osteotomy lines, the von Mises stress values on the fixation devices, and the maximum tensile and compressive stress values on the bone in contact with the screws and the temporomandibular joints (TMJ) were compared.

Results

The displacement in the osteotomy line in the models using the CFR-PEEK polymer was higher than in the titanium models. The stress on the miniplate and screws in the CFR-PEEK models was lower than that in the titanium models. The maximum stress on the miniplates was found close to the fracture line in the distal segment. The stress on the TMJ of the CFR-PEEK models was higher than that of the titanium models.

When the fixation designs were compared regardless of the material, the lowest displacement value (CFR-PEEK: 0.268 mm; Titanium: 0.253 mm), the highest screw stress (CFR-PEEK: 372.9 MPa; Titanium: 1185.5 MPa), and the lowest bone stress (CFR-PEEK: 57.216 MPa; Titanium:64.022 MPa) were observed in the models using the inverted-L technique for fixation.

Conclusion

The results suggest that CFR-PEEK plates and screws reduce stress on the fixation systems and the associated bone while increasing stress on the TMJ.

Abstract

Purpose

Electrical Impedance Tomography (EIT) holds promise as a non-invasive method for measuring lung airflow, particularly in patients diagnosed with Chronic Obstructive Pulmonary Disease (COPD). Nonetheless, there are challenges regarding the clinical relevance of EIT. The main purpose of the present research was to identify the primary frequency components of impedance changes recorded by EIT and correlate them with pulmonary function parameters.

Methods

20 COPD patients were analyzed. Each volunteer was connected to a pneumotachometer and an EIT device. They performed three respiratory exercises, and pulmonary function parameters for each volunteer were acquired. The three impedance signals were convolved to simulate the behavior of the thorax as a black box with a single output signal. The convolved impedance signal was analyzed using FFT spectra. Subsequently, it was divided into seven frequency ranges, estimating the area under the curve and quartiles at 25%, 50%, and 75%. Each segment of the FFT spectrum was correlated with each pulmonary function test parameter.

Results

A significant correlation of over 60% between pulmonary function test parameters and the determinations from the FFT spectrum within seven distinct frequency ranges was observed. However, the determination coefficient (R²) ranged from approximately 10–66% due to data points that did not fit well, particularly in patients with severe pulmonary dysfunction.

Conclusion

To address the dispersion of data and enhance the correlation between determinations, it is imperative to adjust impedance determinations using anthropometric parameters or employ a mathematical equation that facilitates the characterization of limitations in lung airflow.

Purpose

Deep tissue imaging can be achieved using shortwave infrared (SWIR) light, ranging from 900 to 2500 nm in wavelength. SWIR light has several advantages, such as low scattering, reduced photobleaching and autofluorescence, and high sensitivity for biological samples. One of the most efficient materials for SWIR emission is rare-earth-doped nanoparticles (RENP), but they are hydrophobic and incompatible with biological systems. Therefore, we use common surface modifiers, such as polyethylene glycol (PEG) and Tween 20 (Tw), to improve the biocompatibility and dispersibility of RENP in aqueous media. This study aims to evaluate the effects of PEG and Tw as surface modifiers on the stability and SWIR emission intensity of RENP.

Methods

Using the thermal decomposition method, we prepared RENP (NaYF₄: Yb, Er) and modified their surface with PEG and Tw. RENP were modified with PEG and Tw using simple phase inversion and sonication-assisted methods, respectively. We characterized the RENP-PEG and RENP-Tw by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectroscopy, zeta potential, and thermogravimetric analysis (TGA). We also measured the SWIR emission and spectra of the RENP-PEG and RENP-Tw using a Ninox 640 VIS-SWIR InGaAs camera with a 980 nm NIR laser excitation. To assess the biocompatibility of RENP-Tw, we performed an MTT assay with L929 cells.

Results

The XRD and FTIR analyses confirmed the successful surface modification of RENP and the formation of the hexagonal phase β-NaYF₄. The FTIR spectra showed the characteristic peaks of the functional groups associated with PEG and Tw. The surface modification also changed the zeta potential values of RENP, indicating different surface charges. The stability studies revealed that RENP-Tw remained well-dispersed in aqueous media after 24 h, while RENP-PEG aggregated over time. The RENP-Tw showed bright SWIR emission and a prominent peak at 1385 nm. The biocompatibility assay revealed that RENP-Tw did not cause significant cytotoxicity even at high concentrations (400 μg/mL) for 24 h.

Conclusion

Based on our findings, we propose that Tw is a suitable modifier for rare-earth-doped nanoparticles' performance as a SWIR agent, as it improves their stability properties in aqueous media, biocompatibility, and luminescence emissions.

Purpose

Apigenin is a widespread phytochemical with beneficial effects on osteoblastic differentiation. However, short half-life and unstable chemical structure restrict apigenin application in bone tissue engineering applications. Here, we investigated the impact of apigenin-loaded chitosan/gelatin (Api. Cs/Gel) membranes on the osteogenic differentiation of human adipose-derived mesenchymal stem cells (hADMSCs).

Methods

Api10. Cs/Gel and Api25. Cs/Gel membranes were fabricated using the solution casting method, followed by characterizing their physicochemical and biological properties. hADMSCs were isolated from healthy donors and characterized using flow cytometry. hADMSCs were seeded onto Api. Cs/Gel membranes and cultured under osteogenic differentiation for 7 and 21 days. The expression of osteogenic markers ALP, RUNX2, OCN, and COL1 was assessed using real-time PCR, and calcium mineralization was analyzed using the quantitative Alizarin red S staining.

Results

The Api. Cs/Gel membranes were successfully fabricated, and characterization data confirmed their structural uniformity, chemical homogeneity, cross-linking, and apigenin incorporation. Membranes exhibited favorable degradation, swelling ratio, and long-term apigenin release. The membranes were non-toxic and supported hADMSCs attachment, viability, and proliferation. The expression of ALP, RUNX2, OCN, and COL1 and cellular mineralization increased on day 21, and significant overexpression was observed in hADMSCs seeded onto Apigenin-loaded membranes.

Conclusion

Cs/Gel membranes provided an approving matrix for cellular interactions and apigenin inclusion, followed by a sustained release associated with enhanced osteogenic differentiation of hADMSCs and matrix mineralization.

Purpose

This study aims to improve the predictive ability of prostate cancer aggressiveness by leveraging complementary information from various feature types extracted from multi-modal images. We propose a prediction model that incorporates Joint Feature Matrix (JFM) features to capture feature-level correlations between T2-weighted magnetic resonance image (T2wMRI) and apparent diffusion coefficient map (ADC).

Methods

The method involves registering T2wMRI and ADC with ground truth pathology image, enabling identification of prostate cancer regions in T2wMRI and ADC based on pathology image. Uni-modal radiomic features are then extracted from each region of T2wMRI and ADC, while the multi-modal radiomic feature, JFM, is extracted to capture feature-level relationships. Subsequently, a random forest classifier is trained using various combinations of the extracted features to predict aggressiveness of prostate cancer and a feature importance analysis is conducted to identify the most significant features on prediction results.

Results

The experimental results show that incorporating multi-modal radiomic features improves the performance of prediction models. Specifically, using the Concatenated feature enhances specificity by 6.71% and 2.94% compared to the use of T2wMRI and ADC features alone, respectively, indicating improved ability to distinguish the low Gleason score (GS) group by considering both T2wMRI and ADC features. Furthermore, JFM features alone exhibit a higher area under the curve (AUC) compared to Concatenated, Averaged, and Multiplied features. However, the best performance is achieved by combining T2wMRI and ADC features with JFM features, resulting in an AUC improvement of 4.41%, 5.97%, 5.97%, 7.58%, 5.97%, and 2.9% compared to prediction models based on T2wMRI, ADC, Concatenated, Averaged, Multiplied, and JFM features, respectively.

Conclusion

The proposed method effectively captures the joint distribution of features from multiple MRI modalities and demonstrates that consideration of feature-level correlations leads to improved prediction results for prostate cancer aggressiveness.

Purpose

Preoperative simulations tailored to the therapeutic device are desirable to predict treatment efficacy. We investigated the hemodynamics associated with complete obliteration (CO) of intracranial aneurysms after endovascular treatment by computational fluid dynamics (CFD) using porous media modeling.

Methods

From June 2015 to December 2020, 48 patients with 55 unruptured aneurysms treated with simple coiling or stent-assisted coiling at our institution were included. Patient-specific geometry models were generated from pre-treatment 3 dimension (D) rotational angiography or 3D computed tomography angiography. We simulated the coil and neck-bridging stent with porous media modeling for steady state analysis and calculated residual flow volume (RFV) associated with thrombosis formation after coil embolization. Patients were classified into CO and non-CO groups based on digital subtraction angiography findings after 6 months of treatment, and the groups were statistically evaluated using the Brunner-Munzel test. The area under the receiver operating characteristic (ROC) curve (AUC) was used to evaluate the diagnostic accuracy in predicting CO.

Results

The aneurysms were classified into 22 CO and 33 non-CO group. There were no significant differences in morphological variables between the two groups. In hemodynamic parameters, RFV was significantly lower in the CO group. The ROC curve analyses showed that RFV with an average flow velocity of more than 0.5 [cm/s] in aneurysm was the most useful to predict CO (AUC, 0.66 [95% CI, 0.51–0.81]; cut-off value, 32.8 mm³; sensitivity, 60.6%; and specificity, 78.9%).

Conclusion

These results indicated that CFD could predict aneurysmal CO after coil embolization.

Purpose

Percutaneous coronary intervention is widely used as a primary treatment for cardiovascular diseases. In this regard, it has been revealed from studies that zinc is a potential material for use in stents due to its intrinsic physiological relevance, biocompatibility, biodegradability, and pro-regeneration properties. However, localized corrosion and burst release of zinc ions might cause an early implant failure and a risky environment for vascular remodeling. To resolve these drawbacks effectively, a coating of zinc phosphate on pure zinc was fabricated in this study using a microwave-assisted chemical conversion method.

Methods

In this study, a comprehensive analysis was conducted through materials characterization, electrochemical testing, immersion testing, in vitro testing, and hemocompatibility evaluation to quantify the effect of zinc phosphate coating on zinc cardiovascular stents.

Results

It is revealed that the microstructures of the coatings are mainly composed of zinc phosphate and sodium zinc phosphate. The presence of sodium zinc phosphate could improve corrosion behavior. The assessment of in vitro biocompatibility for the zinc phosphate coatings revealed satisfactory cell viability and a stable and smooth degradation surface for cell adhesion. Furthermore, the zinc phosphate coatings exhibited nonhemolytic properties and inhibitions to the adhesion of platelets.

Conclusion

The zinc phosphate coatings could exhibit a uniform degradation behavior and a positive biological effect on vascular remodeling, and therefore, these coatings could be a promising surface treatment used in stent optimization for zinc.