Ultrasound-Induced Tumor Perfusion Changes and Doxorubicin Delivery: A Study on Pulse Length and Pulse Repetition Frequency.

OBJECTIVES: To investigate the appropriate combination of pulse length (PL) and pulse repetition frequency (PRF) when performing ultrasound stimulated microbubble (USMB) to enhance doxorubicin (DOX) delivery to tumors. METHODS: A total of 48 tumor-bearing mice were divided into four groups, namely groups A-D. The mice in groups B-D were treated with chemotherapy and USMB treatment with different combinations of PL and PRF, and group A was control. Contrast-enhanced ultrasound imaging was conducted to analyze tumor blood perfusion. Fluorescence microscopy and high-performance liquid chromatography were used to qualitatively and quantitatively analyse DOX release. The structural changes of tumors were observed under light microscope and transmission electron microscope. Furthermore, another 24 tumor-bearing mice were treated with sonochemotherapy and some related inflammatory factors were measured to explore the underlying mechanism. RESULTS: With PL of three cycles and PRF of 2 kHz, the tumor perfusion area ratio increased by 26.67%, and the DOX concentration was 4.69 times higher than the control (P < .001). With PL of 34.5 cycles and PRF of 200 Hz, the tumor perfusion area ratio decreased by 12.7% and DOX did not exhibit increased extravasation compared with the control. Microvascular rupture and hemorrhage were observed after long PL and low PRF treatment. While vasodilation and higher levels of some vasodilator inflammatory factors were found after treatment with short PL and high PRF. CONCLUSIONS: USMB treatment using short PL and high PRF could enhance tumor blood perfusion and increase DOX delivery, whereas long PL and low PRF could not serve the same purpose.

Telbivudine-induced rhabdomyolysis in a patient undergoing haemodialysis: A case report and review of literature.

Herein, we describe a case of acute rhabdomyolysis in a man in his early 50s undergoing haemodialysis and receiving the antiviral drug, telbivudine, for chronic hepatitis B virus (HBV) infection. Following diagnosis by electromyography (EMG), magnetic resonance image (MRI) scans and laboratory data (i.e., elevated serum creatinine kinase (CK) and myoglobin) telbivudine was discontinued and the patient was treated with methylprednisolone. While his CK and myoglobin levels decreased rapidly, his muscle weakness and pain improved slowly. Learning points include: patients undergoing haemodialysis and concomitantly receiving antiviral treatment for HBV, should have their serum levels of CK and myoglobin monitored regularly; treatment with corticosteroids maybe required; relief from rhabdomyolysis-induced muscle weakness and pain may be slow due to nerve fibre damage.

Comparison of six machine learning methods for differentiating benign and malignant thyroid nodules using ultrasonographic characteristics.

BACKGROUND: Several machine learning (ML) classifiers for thyroid nodule diagnosis have been compared in terms of their accuracy, sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), and area under the receiver operating curve (AUC). A total of 525 patients with thyroid nodules (malignant, n = 228; benign, n = 297) underwent conventional ultrasonography, strain elastography, and contrast-enhanced ultrasound. Six algorithms were compared: support vector machine (SVM), linear discriminant analysis (LDA), random forest (RF), logistic regression (LG), GlmNet, and K-nearest neighbors (K-NN). The diagnostic performances of the 13 suspicious sonographic features for discriminating benign and malignant thyroid nodules were assessed using different ML algorithms. To compare these algorithms, a 10-fold cross-validation paired t-test was applied to the algorithm performance differences. RESULTS: The logistic regression algorithm had better diagnostic performance than the other ML algorithms. However, it was only slightly higher than those of GlmNet, LDA, and RF. The accuracy, sensitivity, specificity, NPV, PPV, and AUC obtained by running logistic regression were 86.48%, 83.33%, 88.89%, 87.42%, 85.20%, and 92.84%, respectively. CONCLUSIONS: The experimental results indicate that GlmNet, SVM, LDA, LG, K-NN, and RF exhibit slight differences in classification performance.

A new sonoablation using acoustic droplet vaporization and focused ultrasound: A feasibility study.

BACKGROUND: Histotripsy and boiling histotripsy are two methods of mechanical ablation that use high-pressure focused ultrasound (FUS). PURPOSE: Here, a new bubble sonoablation technique was investigated using low-pressure FUS in combination with local injection of perfluoropentane (PFP) in rabbit liver. METHODS: Fifteen healthy New Zealand white rabbits were treated with FUS alone, FUS + PFP or PFP alone. FUS was performed using a single-element focused transducer (frequency 596 kHz, 0.27 ms pulses, 0.54% duty cycle, and peak negative pressure 2.0 MPa). Ten minutes before FUS treatment, the PFP droplet was locally injected into the rabbit liver, where the ultrasound was focused. Contrast-enhanced ultrasound (CEUS) of the liver was performed, and the temperature at the liver surface in the targeted liver region was recorded during treatment. The livers were collected for pathological examination. Statistical significance was set at p < 0.05. Paired t-tests were used to compare the pre- and post-treatment values. One-way analysis of variance was performed to compare multiple groups, and the least significant difference method was used for further comparisons between the two groups. RESULTS: Analysis of CEUS data showed that the values of area under the curve (AUC) were significantly different in the PFP + FUS group pre- (10453.644 ± 1182.93) and post-treatment (4058.098 ± 2720.41), and the AUC values of PFP + FUS post-treatment (4058.098 ± 2720.41) were also significantly lower than those of the FUS (9946.694 ± 1071.54) and the PFP (10364.794 ± 2181.53) groups. The peak intensity values also showed the same results, the value of peak intensity of PFP+FUS post-treatment was 82.958 ± 13.99, whereas there was no difference between FUS (106.61 ± 7.61) and PFP (104.136 ± 10.55). Hematoxylin and eosin (H&E) staining revealed that the pathological damage ratings of the PFP + FUS, PFP, and FUS groups were grade 3, grade 1, and grade 0, respectively. Specifically, the area of liver necrosis in the PFP + FUS group (0.99 ± 0.29 cm2 ) was 198 times higher than that in the PFP group (0.005 ± 0.008 cm2 ), whereas no necrosis was observed in the livers treated with FUS alone. Simultaneously, the number of vacuoles in the liver of the PFP + FUS group (35.50 ± 23.31) was approximately five times that of the PFP group (7.00 ± 12.88), whereas no vacuoles were found in the liver treated with FUS alone. CONCLUSION: PFP droplets combined with FUS can destroy liver tissue and cause tissue necrosis in the droplet injection area, without affecting the structure of surrounding tissue.

Optimal treatment occasion for ultrasound stimulated microbubbles in promoting gemcitabine delivery to VX2 tumors.

Ultrasound stimulated microbubbles (USMB) is a widely used technology that can promote chemotherapeutic delivery to tumors yet the best treatment occasion for USMB is unknown or ignored. We aimed to determine the optimal treatment occasion for USMB treatment to enhance tumor chemotherapy to achieve the highest drug concentration in tumors. Experiments were conducted on VX2 tumors implanted in 60 rabbits. Gemcitabine (GEM) was intravenously infused as a chemotherapeutic agent and USMB was administered before, during or after chemotherapy. USMB was conducted with a modified diagnostic ultrasound at 3 MHz employing short bursts (5 cycles and 0.125% duty cycle) at 0.26 MPa in combination with a lipid microbubble. Subsequently, tumor blood perfusion quantitation, drug concentration detection, and fluorescence microscopy were performed. The results showed that the group that received USMB treatment immediately after GEM infusion had the highest drug concentration in tumors, which was 2.83 times that of the control group. Fifteen tumors were then treated repeatedly with the optimal USMB-plus-GEM combination, and along with the GEM and the control groups, were studied for tumor growth, tumor cell proliferation, apoptosis, and related cytokine contents. The combined treatment significantly inhibited tumor growth and promoted apoptosis. The levels of related cytokines, including HIF-1α, decreased after six combination therapies. These results suggest that the optimal treatment occasion for USMB occurs immediately after chemotherapy and tumor hypoxia improves after multiple combination therapies.

Spatially-directed angiogenesis using ultrasound-controlled release of basic fibroblast growth factor from acoustically-responsive scaffolds.

Vascularization is a critical step following implantation of an engineered tissue construct in order to maintain its viability. The ability to spatially pattern or direct vascularization could be therapeutically beneficial for anastomosis and vessel in-growth. However, acellular and cell-based strategies to stimulate vascularization typically do not afford this control. We have developed an ultrasound-based method of spatially- controlling regenerative processes using acellular, composite hydrogels termed acoustically-responsive scaffolds (ARSs). An ARS consists of a fibrin matrix doped with a phase-shift double emulsion (PSDE). A therapeutic payload, which is initially contained within the PSDE, is released by an ultrasound-mediated process called acoustic droplet vaporization (ADV). During ADV, the perfluorocarbon (PFC) phase within the PSDE is vaporized into a gas bubble. In this study, we generated ex situ four different spatial patterns of ADV within ARSs containing basic fibroblast growth factor (bFGF), which were subcutaneously implanted in mice. The PFC species within the PSDE significantly affected the morphology of the ARS, based on the stability of the gas bubble generated by ADV, which impacted host cell migration. Irrespective of PFC, significantly greater cell proliferation (i.e., up to 2.9-fold) and angiogenesis (i.e., up to 3.7-fold) were observed adjacent to +ADV regions of the ARSs compared to -ADV regions. The morphology of the PSDE, macrophage infiltration, and perfusion in the implant region were also quantified. These results demonstrate that spatially-defined patterns of ADV within an ARS can elicit spatially-defined patterns of angiogenesis. Overall, these finding can be applied to improve strategies for spatially-controlling vascularization. STATEMENT OF SIGNIFICANCE: Vascularization is a critical step following implantation of an engineered tissue. The ability to spatially pattern or direct vascularization could be therapeutically beneficial for inosculation and vessel in-growth. However, acellular and cell-based strategies to stimulate vascularization typically do not afford this control. We have developed an ultrasound-based method of spatially-controlling angiogenesis using acellular, composite hydrogels termed acoustically-responsive scaffolds (ARSs). An ARS consists of a fibrin matrix doped with a phase-shift double emulsion (PSDE). An ultrasound-mediated process called acoustic droplet vaporization (ADV) was used to release basic fibroblast growth factor (bFGF), which was initially contained within the PSDE. We demonstrate that spatially-defined patterns of ADV within an ARS can elicit spatially-defined patterns of angiogenesis in vivo. Overall, these finding can improve strategies for spatially-controlling vascularization.

Effect of diagnostic ultrasound and microbubble-enhanced chemotherapy on metastasis of rabbit VX2 tumor.

PURPOSE: Ultrasound-targeted microbubble destruction (UTMD) has been widely applied to enhance chemotherapy of tumors, yet few studies have focused on the metastatic potential induced by UTMD. This study aimed to explore the metastasis of VX2 tumors after treatment with UTMD and chemotherapy. METHODS: Forty-four New Zealand rabbits bearing subcutaneous VX2 tumors were enrolled for the treatment of UTMD with chemotherapy. For UTMD, the tumors were insonated using two pulsing protocols of diagnostic ultrasound (DUS, VINNO and ECARE) with a mechanical index (MI) of 0.29-0.33, tone burst of 8.0 cycles, and frequencies of 3-4 MHz. A total dose of 2 ml SonoVue® was injected intermittently during 10-min UTMD exposure. The combination therapy was treated using doxorubicin (DOX, 2 mg/kg) and DUS, while the tumors treated using DOX only served as the control. Tumor size was measured using the tumor volume formula. Survival time was observed until animal death or the end of the study (120 days). Specific organs (lung, liver, kidney, and brain) were removed for metastatic evaluation. RESULTS: There were no statistical differences in overall metastasis classification and individual organ metastases among all groups (P > 0.05). The tumor growth rate only showed inhibition on the 5th day (P < 0.01). The survival time did not demonstrate any significant difference between UTMD and chemotherapy only (P > 0.05). CONCLUSIONS: UTMD using long-pulse DUS with commercial microbubbles did not pose a risk of metastasis enhancement in DOX chemotherapy.

Spatially-directed cell migration in acoustically-responsive scaffolds through the controlled delivery of basic fibroblast growth factor.

Hydrogels are commonly used in regenerative medicine for the delivery of growth factors (GFs). The spatial and temporal presentations of GFs are critical for directing regenerative processes, yet conventional hydrogels do not enable such control. We have developed a composite hydrogel, termed an acoustically-responsive scaffold (ARS), where release of a GF is non-invasively and spatiotemporally-controlled using focused ultrasound. The ARS consists of a fibrin matrix doped with a GF-loaded, phase-shift emulsion. The GF is released when the ARS is exposed to suprathreshold ultrasound via a mechanism termed acoustic droplet vaporization. In this study, we investigate how different spatial patterns of suprathreshold ultrasound can impact the biological response upon in vivo implantation of an ARS containing basic fibroblast growth factor (bFGF). ARSs were fabricated with either perfluorohexane (bFGF-C6-ARS) or perflurooctane (bFGF-C8-ARS) within the phase-shift emulsion. Ultrasound generated stable bubbles in bFGF-C6-ARS, which inhibited matrix compaction, whereas transiently stable bubbles were generated in bFGF-C8-ARS, which decreased in height by 44% within one day of implantation. The rate of bFGF release and distance of host cell migration were up to 6.8-fold and 8.1-fold greater, respectively, in bFGF-C8-ARS versus bFGF-C6-ARS. Ultrasound increased the formation of macropores within the fibrin matrix of bFGF-C8-ARS by 2.7-fold. These results demonstrate that spatially patterning suprathreshold ultrasound within bFGF-C8-ARS can be used to elicit a spatially-directed response from the host. Overall, these findings can be used in developing strategies to spatially pattern regenerative processes. STATEMENT OF SIGNIFICANCE: Hydrogels are commonly used in regenerative medicine for the delivery of growth factors (GFs). The spatial and temporal presentations of GFs are critical for directing regenerative processes, yet conventional hydrogels do not enable such control. We have developed a composite hydrogel, termed an acoustically-responsive scaffold (ARS), where GF release is non-invasively and spatiotemporally-controlled using focused ultrasound. The ARS consists of a fibrin matrix doped with a phase-shift emulsion loaded with GF, which is released when the ARS is exposed to ultrasound. In this in vivo study, we demonstrate that spatially patterning ultrasound within an ARS containing basic fibroblast growth factor (bFGF) can elicit a spatially-directed response from the host. Overall, these findings can be used in developing strategies to spatially pattern regenerative processes.

Quantitative evaluation of tissue stiffness around lesion by sound touch elastography in the diagnosis of benign and malignant breast lesions.

The purpose of our study is to assess the diagnostic performance of quantitative evaluation of tissue stiffness around lesion by Sound Touch Elastography (STE) in distinguishing between benign and malignant breast lesions. A total number of 160 breast lesions from 160 female patients were examined by STE. Resona 7 was equipped with "shell" function to measure elastic modulus values of tissue in the region of surrounding lesion quantitatively. The contours of the lesion were required to be delineated. The elastic modulus values of tissue in the region of 1mm, 2mm, and 3mm outside the boundary were acquired. The elastic modulus values included maximum elastic modulus (Emax), mean elastic modulus (Emean), minimum elastic modulus (Emin), and elastic modulus standard deviation (Esd). All lesions were confirmed by histopathology. We compared the differences of the above elastic modulus values between benign and malignant groups. Receiver operating characteristic (ROC) curve was drawn with the histological diagnostic results as the gold standard. Sensitivity and specificity were calculated to evaluate the diagnostic performance of STE. Operator consistency was also analyzed. Among the 160 lesions, 100 (62.5%) were benign and 60 (37.5%) were malignant. In the region of 1mm, 2mm, and 3mm surrounding the lesion, Emax, Emean, and Esd of malignant group were significantly higher than those of the benign group (all P<0.05). When the "shell" was 3mm, Emax had the highest AUROC value (AUROC = 0.998). Regarding the measurement of elastic modulus values, all the intra-class correlation coefficient (ICC) values of the inter-operator consistency were greater than 0.75 for Emax, Emean, and Esd. Therefore, quantitative evaluation of tissue stiffness around lesion by STE has the potential to distinguish between benign and malignant breast lesions.

Logistic regression analysis of conventional ultrasonography, strain elastosonography, and contrast-enhanced ultrasound characteristics for the differentiation of benign and malignant thyroid nodules.

The aim of the study is to screen the significant sonographic features by logistic regression analysis and fit a model to diagnose thyroid nodules. A total of 525 pathological thyroid nodules were retrospectively analyzed. All the nodules underwent conventional ultrasonography (US), strain elastosonography (SE), and contrast -enhanced ultrasound (CEUS). Those nodules' 12 suspicious sonographic features were used to assess thyroid nodules. The significant features of diagnosing thyroid nodules were picked out by logistic regression analysis. All variables that were statistically related to diagnosis of thyroid nodules, at a level of p < 0.05 were embodied in a logistic regression analysis model. The significant features in the logistic regression model of diagnosing thyroid nodules were calcification, suspected cervical lymph node metastasis, hypoenhancement pattern, margin, shape, vascularity, posterior acoustic, echogenicity, and elastography score. According to the results of logistic regression analysis, the formula that could predict whether or not thyroid nodules are malignant was established. The area under the receiver operating curve (ROC) was 0.930 and the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 83.77%, 89.56%, 87.05%, 86.04%, and 87.79% respectively.

Correlation Analysis between Polysomnography Diagnostic Indices and Heart Rate Variability Parameters among Patients with Obstructive Sleep Apnea Hypopnea Syndrome.

Heart rate variability (HRV) can reflect the changes in the autonomic nervous system (ANS) that are affected by apnea or hypopnea events among patients with obstructive sleep apnea hypopnea syndrome (OSAHS). To evaluate the possibility of using HRV to screen for OSAHS, we investigated the relationship between HRV and polysomnography (PSG) diagnostic indices using electrocardiography (ECG) and PSG data from 25 patients with OSAHS and 27 healthy participants. We evaluated the relationship between various PSG diagnostic indices (including the apnea hypopnea index [AHI], micro-arousal index [MI], oxygen desaturation index [ODI]) and heart rate variability (HRV) parameters using Spearman's correlation analysis. Moreover, we used multiple linear regression analyses to construct linear models for the AHI, MI, and ODI. In our analysis, the AHI was significantly associated with relative powers of very low frequency (VLF [%]) (r = 0.641, P = 0.001), relative powers of high frequency (HF [%]) (r = -0.586, P = 0.002), ratio between low frequency and high frequency powers (LF/HF) (r = 0.545, P = 0.049), normalized powers of low frequency (LF [n.u.]) (r = 0.506, P = 0.004), and normalized powers of high frequency (HF [n.u.]) (r = -0.506, P = 0.010) among patients with OSAHS. The MI was significantly related to standard deviation of RR intervals (SDNN) (r = 0.550, P = 0.031), VLF [%] (r = 0.626, P = 0.001), HF [%] (r = -0.632, P = 0.001), LF/HF (r = 0.591, P = 0.011), LF [n.u.] (r = 0.553, P = 0.004), HF [n.u.] (r = -0.553, P = 0.004), and absolute powers of very low frequency (VLF [abs]) (r = 0.525, P = 0.007) among patients with OSAHS. The ODI was significantly correlated with VLF [%] (r = 0.617, P = 0.001), HF [%] (r = -0.574, P = 0.003), LF [n.u.] (r = 0.510, P = 0.012), and HF [n.u.] (r = -0.510, P = 0.012) among patients with OSAHS. The linear models for the PSG diagnostic indices were AHI = -38.357+1.318VLF [%], MI = -13.389+11.297LF/HF+0.266SDNN, and ODI = -55.588+1.715VLF [%]. However, the PSG diagnostic indices were not related to the HRV parameters among healthy participants. Our analysis suggests that HRV parameters are powerful tools to screen for OSAHS patients in place of PSG monitoring.

The changes of HRV in refractory epilepsy: The potential index to predict the onset of epilepsy in children.

In this study, we examine the potential of heart rate variability (HRV) as an efficient tool for predicting the onset of epilepsy in children. We totally collected 53 seizures EEG and ECG data using Video - EEG - ECG monitoring system. We then separated the ECG data into three segments: ten-minute before onset of each seizure, five-minute before onset of each seizure, and five-minute from the onset of each seizure. After the HRV parameters in all segments were calculated, we compared the differences between pre-ictal period and ictal period. We found that the values of meanHR, LF and LF/HF were greater in onset period. And the values of meanRR and the HF were less in ictal period. And it presented the similar changes when seizures occurred in the daytime and seizures occurred in the nighttime. In brief, we found that the sympathetic nervous system was under a more active status during onset period. We speculated that the HRV parameters such as the LF, HF or LF/HF could have potential to predict the seizures in children with epilepsy.