Optimizing the administrated light dose during 5-ALA-mediated photodynamic therapy: Murine 4T1 breast cancer model.

Photodynamic therapy (PDT) is already used to treat many cancers, including breast cancer, the most common cancer in women worldwide. The destruction basis of this method is on produced singlet oxygen which is extremely reactive and is a major agent of tumor cell killing. The measurement of singlet oxygen produced within PDT is essential in predicting treatment outcomes and their optimization. This study aims to determine the optimal total light dose administered during PDT by calculating the singlet oxygen to facilitate the prediction of the treatment outcome in mice bearing 4T1 cell breast cancer. Monitoring the changes in photosensitizer fluorescence signals during PDT due to photobleaching can be one of the methods of determination of singlet oxygen generation in the PDT process. This study determined the oxygen singlet as a photodynamic dose from the three-dimensional Monte Carlo method and the photobleaching empirical dose constant. The photobleaching dose constant was established non-invasively by monitoring the in vivo protoporphyrin IX (PpIX) fluorescence and photobleaching during PDT. The photobleaching dose constant (ß) in J/cm2 was calculated using empirical fluorescence data. The in vivo photobleaching dose constant of aminolevulinic acid was found to be 11.6 J/cm2 and based on this value, the optimal treatment light dose was estimated at 120 J/cm2 in mice bearing 4T1 breast cancer. It is concluded that information can be obtained regarding optimal treatment parameters by monitoring the in vivo PpIX fluorescence and photobleaching during PDT.

Numerical study of high-intensity focused ultrasound (HIFU) in fat reduction.

INTRODUCTION: This study aimed to investigate the effect of fat-layer thickness and focal depth on the pressure and temperature distribution of tissue. METHODS: Computer simulations were performed for the skin-fat layer models during high-intensity focused ultrasound (HIFU) treatment. The acoustic pressure field was calculated using the nonlinear Westervelt equation and coupled with the Pennes bioheat transfer equation to obtain the temperature distribution. To investigate the effect of the thickness of the fat layer on pressure and thermal distributions, the thickness of the fat layer behind the focal point (z = 13.5 mm) changed from 8 to 24 mm by 2 mm step. The pressure and temperature distribution spectra were extracted. RESULTS: The simulated results were validated using the experimental results with a 98% correlation coefficient (p < 0.05). There was a significant difference between the pressure amplitude and temperature distribution for the 8-14 mm thickness of the fat layer (p < 0.05). By changing the focal point from 11.5 to 13.5 mm, the maximum acoustic pressure at the focal point increased 66%, and the maximum temperature was 56%, respectively. CONCLUSION: Considering the specific treatment plan for each patient, according to the skin and fat layer thicknesses, can help prevent side effects and optimize the treatment process of HIFU.

Ultrasound evidence of altered lumbar fascia in patients with low back pain.

Different hypotheses have been proposed about the role of lumbar connective tissue in low back pain (LBP). However, none of the previous studies have examined the change in the elastic behavior of lumbar fascia in patients with LBP. The present study aimed to evaluate the changes in the elastic behavior of lumbar fascia in patients with chronic non-specific LBP based on ultrasound imaging. The sonographic strain imaging assessed the thoracolumbar fascia (TLF) of 131 human subjects (68 LBP and 63 non-LBP). Assessments were done at L2-L3 and L4-L5 levels bilaterally. The points were located 2 cm lateral to the midpoint of the interspinous ligament. There were no significant differences in age, sex, and BMI between LBP and healthy individuals. There is a strong inverse relationship between pain severity (r = -0.76, n = 68, p = 0.004) and the TLF elastic modulus coefficient. No significant relationship were observed between age (r = 0.053, n = 68, p = 0.600), BMI (r = -0.45, n = 68, p = 0.092), and gender (r = -0.09, n = 68, p = 0.231) with the TLF elasticity coefficient. The LBP group had a 25%-30% lower TLF elastic modulus coefficient than healthy individuals. The present study is the first to evaluate the elastic coefficient of TLF using the ultrasound imaging method. The study results showed that the TLF elastic coefficient in patients with LBP was reduced compared to healthy individuals and directly related to LBP severity.

Estimation of the segmental left ventricular physical and mechanical parameters using echocardiographic imaging for stent candidate patients.

PURPOSE: Left ventricular (LV) dysfunction can be assessed by quantifying LV structure. In this study, physical parameters were extracted, including the systolic strain, wall stress, and elastic modulus of LV to diagnose stent candidate patients from the control group. METHODS: Based on angiography results, 88 patients with coronary artery disease (CAD) were divided into 64 patients candidates for PCI (percutaneous coronary intervention) and 24 patients in the control group. With the thick-walled ellipsoidal model, the passive wall stresses at end-systole and end-diastole were estimated. Regional circumferential strain and regional longitudinal strain were obtained by speckle tracking technique. RESULTS: The inferoseptal circumferential wall stress in end-systole was statistically significant for the PCI group compared to the control group (p = .026). Anterior and inferoseptal circumferential strain for the PCI group (-17.25 ± 4.22 and -18.21 ± 4.04%) compared to the control group (-21.71 ± 4.74 and 20.58 ± 3.04%) were statistically significant, respectively (p = .000 and p = .011). Anterior and inferoseptal circumferential elastic modulus were statistically significant (p = .000 and p = .005). The receiver operator characteristic (ROC) curve analysis revealed that anterior and inferoseptal circumferential elastic modulus had the highest area under the curve with 76.6% sensitivity, 83.3% specificity for anterior circumferential, 68.8% sensitivity, and 70.8% specificity for inferoseptal circumferential, for the diagnosis of stent candidate patients. CONCLUSIONS: Regional elastic modulus parameter is suggested as a noninvasive and quantitative method for measuring LV function. Strain and stress parameters using the STE method and geometrical model can be helpful for diagnostic stent candidate patients.

Non-invasive evaluation of elasticity of skin with the processing of ultrasound images during ultraviolet radiation: An animal photoaging model.

OBJECTIVE: The aim of this study was to provide a non-invasive imaging method to evaluate the physical and mechanical parameters as a novelty method during skin photoaging. METHODS: In order to evaluate the process of skin damage, 25 mice (C57BL6) were exposed to UVB radiation (0.03 mW/cm2 ), 5 times a week for 5 weeks. The thickness of the epidermal and dermal layers was measured weekly from the ultrasound images (40 MHz). The elastic parameters of the skin were estimated from the processing of the sequential ultrasound images with the motion detection algorithm during the injury generation process. RESULTS: The thickening, Young modulus, and shear modulus of the dermal and epidermal layers during the UVB damage process significantly increased during the 5-week study period (P < .05). In addition, the percentage of changes in the thickness of the epidermal layer (0.22 ± 0.01 mm in day 0 to 0.37 ± 0.02 mm in day 35) and dermal layer (0.57 ± 0.05 mm in day 0 to 0.90 ± 0.08 mm in day 35) increased by 68% and 57%, respectively. Furthermore, Young modulus (154.41 ± 8.8 kPa) was 11 times more than that of non-irradiated skin (14.90 ± 2.2 kPa) and the shear modulus (2.33 ± 0.04 kPa) was 2.2 times more than non-irradiated skin (1.06 ± 0.04 kPa). CONCLUSION: With processing the sequential ultrasound images and extracting the thickening, the elasticity of the skin layers can detect skin lesions by UVB radiation.

The effect of dual-frequency ultrasound waves on B16F10 melanoma cells: Sonodynamic therapy using nanoliposomes containing methylene blue.

BACKGROUND: We investigated the effect of dual-frequency sonication on the viability of B16F10 melanoma cells in the presence of methylene blue (MB) encapsulated in nanoliposomes. METHODS: Treatment protocols were studied: sonication groups (40 kHz, 1 MHz and dual-frequency), the same sonication groups with nanoliposomes containing MB, MB free and nanoliposomes containing MB groups, and so sham and control groups. The nanoliposomes were prepared by the lipid film hydration method. The cell viability of the different treatment groups was evaluated by the MTT assay. RESULTS: The dual-frequency protocols caused higher viability losses compared to the kHz and MHz sonications (P < .05). In presence of the nanoliposomes containing MB, dual frequency led to 6% and 3% viability for 600 and 1200 seconds, respectively, while the corresponding values were 10% and 4% for the 40 kHz protocols and 22% and 9% for the 1 MHz, as compared to the control group (100%). The result of KI dosimetry showed that the cavitation activity of the dual-frequency protocol was about 1.23, as compared to sonication at 40 kHz and 1 MHz. CONCLUSION: Enhancement of inertial cavitation induction by dual-frequency sonication may be the primary effective mechanism, which causes increased sonochemical processes and drug release from nanocarriers.

Effect of fullerene nanoemulsion on the repair of wrinkles induced by UVB radiation: A c57bl6 mice model.

INTRODUCTION: The effect of fullerene nanoemulsion on skin wrinkle repair in an animal model was evaluated using ultrasonic images processing. METHODS: Wrinkles were created in C57BL6 mice during 35 days of UVB radiation. Then, to investigate the therapeutic effect of fullerene nanoemulsions, mice were divided into three groups of control, UVB radiation, and treatment with fullerene nanoemulsion. Stable fullerene nanoemulsions were prepared using shear equalization. The therapeutic effect of fullerene nanoemulsion was investigated by extracting the skin thickness and mechanical parameters. Histology studies were performed to confirm the reliability of the treatment. RESULTS: A significant decrease was observed in the thickness of the epidermis and dermis layers (43% and 36%), Young modulus (27%), and the shear modulus (20%) of the skin on day 28 of the fullerene nanoemulsion treatment. Skin stiffness obtained by tensiometry on day 28 of the treatment showed a 48% reduction in the treatment group compared with the control group. Histological results confirmed the effect of fullerene nanoemulsions on wrinkle repair. CONCLUSION: The healing effect of fullerene nanoemulsion in wrinkle repair was confirmed. To study the skin repair, parameters including Young modulus, the shear modulus, and skin layer thickness can be calculated using ultrasonic images processing.

Effect of Acoustic Cavitation on Mouse Spermatogonial Stem Cells: Colonization and Viability.

OBJECTIVES: The mechanical index has long been one of the main criteria used to assess the safety limits for therapeutic medical applications. However, the safety of the mechanical index parameter is considered to be unknown in male fertility, which has a very significant role in vitro conditions. In this study, the effect of cavitation interactions due to mechanical index regions was evaluated on spermatogonial stem cells. METHODS: The acoustic pressure and mechanical index equations at the low intensities and the intended frequency were modeled and solved. The mechanical index average of 40 kHz frequency was selected as subthreshold, 0.70, and above the cavitation threshold. Neonatal spermatogonial stem cells were cultured. Spermatogonial stem cells are stimulated by low-level ultrasound for 5 days and colonization and viability evaluated on the seventh day. RESULTS: Based on modeling, the mechanical index average was chosen as 0.40, 0.51, 0.75, and 0.89. The mechanical index of 0.40 and 0.89 resulted in a number of colonies of 93 ± 4 and 32 ± 4, respectively. An increase in colony diameter could be observed for a 0.40 mechanical index during all days of the culture that in the culture on the seventh day had the largest average colony diameter of 174.05 ± 1.22 µm in comparison with other groups (p < 0.05). The cell viability was not significantly different among the groups. CONCLUSION: The results suggest that a low-intensity ultrasound of 40 kHz with a 0.40 mechanical index can be effective in increasing the proliferation and colonization of spermatogonia in stem cells during culture.

Dual-frequency ultrasound activation of nanomicellar doxorubicin in targeted tumor chemotherapy.

INTRODUCTION: This study investigated the therapeutic effect of dual-frequency sonication (3 MHz and 28 kHz) at low intensity levels in combination with micellar doxorubicin in the treatment of a tumor model of spontaneous breast adenocarcinoma in Balb/c mice. METHODS: We used sonication frequencies 28 kHz and 3 MHz and their dual combinations in the progressive wave mode to enhance acoustic cavitation. Then, the antitumor effect of the simultaneous dual-frequency ultrasound (28 kHz and 3 MHz) at low intensity levels in combination with doxorubicin and micellar doxorubicin injection was investigated in a spontaneous model of breast adenocarcinoma in Balb/c mice. Sixty-three tumor-bearing mice were randomly divided into seven groups: control, sham, sonication with dual frequency, doxorubicin without sonication, doxorubicin with dual-frequency sonication, micellar doxorubicin without sonication, and micellar doxorubicin with dual-frequency sonication. The tumor volume change relative to the initial volume, tumor growth inhibition ratio, the required times for each tumor to reach two (T 2) and five (T 5) times its initial volume, and survival period were the tumor growth delay parameters which were calculated and recorded at various times after treatment. RESULTS: The results of the combination of frequencies 28 kHz (0.04 W/cm(2)) and 3 MHz (2.00 W/cm(2)) showed remarkable enhancement of the cavitation activity compared with single-frequency sonication (P < 0.05). The micellar doxorubicin injection with sonication group showed a significant difference in the relative volume percent parameter compared with the other groups (P < 0.05). Additionally, the T 2 and T 5 times in the micellar doxorubicin with sonication group were significantly higher than in the other groups (P < 0.05). Also, the survival period of the mice in the micellar doxorubicin with sonication group was significantly longer than in the other groups (P < 0.05). These findings were verified histopathologically. CONCLUSION: This study shows that simultaneous combined dual-frequency ultrasound sonication in continuous mode is effective in producing cavitation activity at low intensity. We conclude that dual-frequency sonication with micellar doxorubicin injection extends survival in a murine breast adenocarcinoma model.

Evaluation of left anterior descending coronary artery stenosis severity from myocardial end-diastolic wall stress estimated by tissue-Doppler imaging.

PURPOSE: To identify patients with significant coronary artery disease by the noninvasive quantification of myocardial wall stress in diastole. METHODS: We studied 60 male subjects in sinus rhythm with significant (n = 30) or moderate (n = 30) proximal left anterior descending coronary artery stenosis, and 30 healthy subjects (control group). The average end-diastolic wall stress was estimated at left ventricle anterior and interventricular septum wall segments from regional wall thickness, meridional and circumferential regional radii of curvature, and noninvasively estimated left ventricular end-diastolic pressure. RESULTS: There were significant differences in left ventricular end-diastolic pressure between patients and controls (p < 0.05). End-diastolic myocardial wall stress was significantly different between patients with significant and moderate coronary stenosis and healthy subjects in all anterior and septal wall segments (p < 0.05) except for the anterior wall at mid level. The receiver-operating characteristic curves showed that septum apex wall stress has the highest discriminatory power for predicting significant stenosis versus healthy coronary artery with 83% area under the curve. CONCLUSIONS: Estimated end-diastolic myocardial wall stress may help in evaluating regional myocardial dysfunction due to coronary artery disease.

Effect of fractionation on treatment outcome in local dual-frequency sonication and Dox-encapsulated nanomicelles.

PURPOSE: The goal of this study was to localize drug release from nanomicelles using dual-frequency sonication at low levels of acoustic intensity. METHODS: In this study, the antitumor effect of simultaneous dual-frequency sonication (28 kHz and 3 MHz) at low levels of acoustic intensity in combination with doxorubicin and micellar doxorubicin injection was assessed in a spontaneous model of breast adenocarcinoma in female Balb/c mice. Sixty-three tumor-bearing mice were randomly grouped into control, sham, dual-frequency sonication, doxorubicin injection with and without dual-frequency sonication, and micellar doxorubicin injection with and without dual-frequency sonication groups. RESULTS: The results of volume change relative to initial volume showed that in the micellar doxorubicin injection with sonication group, this parameter was significantly different from that of the control, sham, sonication, and doxorubicin injection groups (P < 0.05). In addition, the volume began to increase on the 15th day after the start of treatment, which is a good indication to repeat treatment; therefore, another group received an extra treatment on day 15. The animal life span in the micellar doxorubicin with sonication and repeated treatment groups was significantly higher than that in all the other experimental groups except for the micellar doxorubicin injection group (P < 0.05). CONCLUSION: It was concluded that dual-frequency sonication with micellar doxorubicin injection extends the life span relative to doxorubicin injection or dual-frequency sonication alone, and that repeating this treatment on day 15 decreases the rate of tumor growth significantly.

Biomechanical changes of the common carotid artery and internal jugular vein in patients with multiple sclerosis.

PURPOSE: Investigations of the hemodynamic changes of the venous system in patients with multiple sclerosis (MS) have shown contradictory results. Herein, the biomechanical parameters of the internal jugular vein (IJV) and common carotid artery (CCA) of MS patients were extracted and compared to healthy individuals. METHODS: B-mode and Doppler sequential ultrasound images of 64 IJVs and CCAs of women including 22 healthy individuals, 22 relapsing-remitting multiple sclerosis (RRMS) patients, and 20 primary-progressive multiple sclerosis (PPMS) patients were recorded and processed. The biomechanical parameters of the IJV and the CCA walls during three cardiac cycles were calculated. RESULTS: The IJV maximum and minimum pressures were higher in the MS patients than in the healthy subjects, by 31% and 19% in RRMS patients and 39% and 24% in PPMS patients. The venous wall thicknesses in RRMS and PPMS patients were 51% and 60% higher than in healthy subjects, respectively. IJV distensibility in RRMS and PPMS patients was 70% and 75% lower, and compliance was 40% and 59% lower than in healthy subjects. The maximum intima-media thicknesses of the CCAs were 38% and 24%, and the minimum intima-media thicknesses were 27% and 23% higher in RRMS and PPMS patients than in healthy individuals, respectively. The shear modulus of CCA walls in RRMS and PPMS patients was 17% and 31%, and the radial elastic moduli were 47% and 9% higher than in healthy individuals. CONCLUSION: Some physical and biomechanical parameters of the CCA and IJV showed significant differences between MS patients and healthy individuals.

Comparing the in vivo sonodynamic effects of dual- and single-frequency ultrasound in breast adenocarcinoma.

INTRODUCTION: Dual-frequency ultrasound has recently been shown to extensively enhance the acoustic cavitation yield in water. METHODS: In this study, the in vivo antitumor effect of simultaneous, dual-frequency ultrasound at low-level intensity (I SATA = 2 W/cm(2) for 1 MHz and I SATA = 0.2 W/cm(2) for 150 kHz) in combination with an intravenous injection of 5 mg/kg hematoporphyrin (Hp) was investigated in a model of breast adenocarcinoma in Balb/c mice. Seventy-one tumor-bearing mice were divided into nine treatment groups: control, sham, Hp injection, and single- and dual-frequency sonication in the presence and absence of Hp. The tumor growth delay was then calculated based on the tumor volume at various times after treatment using the following parameters: relative volume percent, [Formula: see text] and [Formula: see text] times (to reach five and two times the initial volume), percent of tumor growth inhibition ratio, and survival period. RESULTS: Our results showed no significant difference between the 150 kHz and 1 MHz single-frequency groups when compared with the sham group after 9 days of treatment (p > 0.05). However, treatment with dual-frequency ultrasound significantly delayed tumor growth when compared with the sham group (p < 0.05) after 9 days of treatment. Furthermore, in vivo experiments showed that combined dual-frequency sonication controlled tumor growth more effectively than single-frequency sonication. Evaluation of the therapeutic effects of single- and dual-frequency ultrasound in sonodynamic therapy revealed that treatment with the combination of dual-frequency ultrasound and Hp resulted in a significant reduction in the relative volume percent of tumors after 3 days of treatment (p < 0.05) compared with the controls. Additionally, the T 5 time and the survival period in the group treated with the combination therapy was significantly longer than those in all the other groups (p < 0.05). These findings were further verified histopathologically. CONCLUSION: In conclusion, our results reveal that sonodynamic therapy using dual-frequency ultrasound is able to extend the survival time of animals compared with single-frequency sonication.

Magnetoporation: New Method for Permeabilization of Cancerous Cells to Hydrophilic Drugs.

Background: In the present study, we investigated the application of pulsed magnetic field (MF) (3.5 T, 1 Hz, 8 square-wave/160 µs) permeabilization on murine breast adenocarcinoma cells when administering bleomycin (BLM) in vivo. Objective: This cross-over study aims to find a noninvasive method to facilitate penetration of hydrophilic anti-cancer drugs through the cancerous cells membrane into the cytosoll in order to minimize the side effects of the chemotherapy treatments of tumors. Material and Methods: In this cross-over study, a total of 50 female Balb/c mice were tumorized via homograft. After about 2 weeks, magnetic pulses (3.5 T, 1 Hz, 8 square-wave/160 µs) were applied to tumor-bearing mice 3 min after intratumoral BLM solution injection. Tumor volume was measured every 48 h during 22 days. Results: The results showed that the difference between the BLM plus 3.5 T MF group versus the sham control or sham MF groups was significant. Uptake of BLM molecules by tumoral cells in the BLM plus 3.5 T MF group versus the BLM control group was 7- folds higher that this result was statistically insignificant (P<0.05, SEM=266.8676, analysis of variance). Conclusion: Significant cell permeabilization to BLM requires greater MF strength or exposure time. Further investigation is necessary.

The effect of dual-frequency sonication in the presence of thalidomide angiogenesis inhibitor and nanomicelles containing doxorubicin on inhibiting the growth and angiogenesis of breast adenocarcinoma in vivo.

This study aimed to evaluate the effect of dual-frequency sonication in the presence of thalidomide angiogenesis inhibitor and nanomicelles containing doxorubicin on inhibiting the growth and angiogenesis of breast adenocarcinoma in BALB/c female mice. Sixty mice carrying the tumor were divided into 12 groups: (A) control, (B) 28 kHz and 3 MHz sonication, (C) thalidomide, (D) thalidomide and 28 kHz, (E) thalidomide and 3 MHz, (F) thalidomide and dual-frequency sonication, (G) doxorubicin, (H) nanomicelles containing doxorubicin, (I) nanomicelles containing doxorubicin and dual-frequency sonication, (J) thalidomide and doxorubicin, (K) thalidomide and nanomicelles containing doxorubicin, and (L) thalidomide and nanomicelles containing doxorubicin and dual-frequency sonication. The delay in the tumor growth and angiogenesis percent were extracted. Pathological and immunohistochemical studies were performed to confirm the treatment. The findings of tumor growth retardation parameters and animal survival were significantly different in group L from all groups (P < 0.05). The highest rate of inhibition was in group L with a 46% inhibition. In group L, 100% of the animals survived until day 49. In groups F, C, G, B, and A, all the animals survived 45, 42, 39, 32, and 30 days, respectively. Pathological results showed a decrease in tumor grade in groups K and L. Histopathological results demonstrate a decrease in group L angiogenesis compared to group C. These findings were consistent with the results of color Doppler ultrasound imaging. Dual-frequency sonication in the presence of thalidomide and doxorubicin-containing nanomicelles inhibits tumor growth and angiogenesis.

The Effects of a 2-W Laser on the Nasolabial Fold of Ageing Individuals Investigated by High-Frequency Ultrasonography: A Nonrandomized Controlled Trial.

Introduction: Biomechanical qualities of the skin tissue change following numerous pathological and natural (ageing) conditions. The best skin treatments are those resulting in a positive outcome with the fewest adverse effects. In this study, high-frequency ultrasonography (US), which provides a quantifiable scale, was utilized to evaluate the impact of a 2-W laser on characteristics of nasolabial fold (NLF) including depth and area, epidermis and dermis thicknesses, and Young's modulus (YM). Methods: Nine female subjects (54.09±0.09 years old) with Fitzpatrick skin types III-IV and five young control participants (26±1.28 years old) for providing the control data were included in this study. Laser therapy was applied twice weekly for seven consecutive sessions. A class IV laser with 810-nm and 980-nm wavelengths, 2-W power, and 25-Hz frequency was applied twice a week for seven consecutive sessions. The energy administered had a density of 8 J/cm2. An evaluation using high-frequency ultrasound (40 MHz) was accomplished before and 48 hours after the final treatment session. The Face-Q questionnaire was used to assess the patient's perspective on this procedure. Results: For each US parameter, the intraclass correlation coefficient was high (ICC>0.9). After the laser treatment, NLF depth, area, epidermis, dermis, YM, and Face-Q significantly improved compared to baseline (P<0.05). Conclusion: For the assessment of skin tissue, high-frequency US is a reliable technique. The 2-W laser is a safe, effective, and non-invasive procedure for enhancing skin features.

Assessing the short-term effects of radiotherapy on the shear modulus of the common carotid artery as a new biomarker of radiation-induced atherosclerosis.

PURPOSE: The purpose of this study was to investigate the incidence of short-term atherosclerosis in the common carotid arteries following radiotherapy. METHODS: The mean radiation dose to the arteries was 49.30±15.83 Gy. A computational ultrasound method was introduced to investigate the elastic modulus. Ultrasonography was performed 2-3 cm inferior to the bifurcation region before and after radiotherapy, and sequential images were extracted from a video of each artery. Instantaneous movement of the arterial wall in the radial and longitudinal directions was extracted by implementing the maximum gradient and block matching algorithms, respectively. RESULTS: There was a significant change in systolic blood pressure after radiotherapy (P=0.008). Irradiated arteries had significantly smaller systolic and end-diastolic diameters than non-irradiated arteries (P<0.001). The shear modulus was significantly different between irradiated and non-irradiated arteries (3.10±2.03 kPa vs. 1.38±0.98 kPa, P<0.001). The shear and Young moduli of radiation-induced arteries were 2.25±1.50 and 1.57±0.59 times higher than those of the pre-irradiation arteries. CONCLUSION: The arterial shear modulus can be considered as a new biomarker of radiationinduced atherosclerosis in the common carotid artery.

Comparative effect of lumbar myofascial release with electrotherapy on the elastic modulus of lumbar fascia and pain in patients with non-specific low back pain.

OBJECTIVES: Low back pain is a major health issue in most industrialized countries. Lumbar fascia is supported as a potential source of pain in the lumbar region. Myofascial release is a manual therapeutic approach that focuses on restoring altered soft tissue function. On the other hand, one of the most commonly used physical therapy methods for low back pain is electrotherapy. The purpose of this study was to compare the effect of lumbar Myofascial release and electrotherapy on clinical outcomes of Non-specific low back pain and elastic modulus of lumbar myofascial tissue. DESIGN: Randomized, clinical trial. SETTING: Outpatient Low back pain clinic. SUBJECTS: 32 subjects with low back pain. INTERVENTIONS: Subjects were randomized into the myofascial release group (n = 16) and electrotherapy group(n = 16). Subjects in the myofascial release group received 4 sessions of myofascial release in the lumbar region, and the electrotherapy group received 10 sessions of electrotherapy. MAIN MEASURES: Low back pain severity, and elastic modulus of the lumbar myofascial tissue were assessed before and after treatment. RESULTS: An independent sample T-test was used to compare baseline variables in both groups (p > 0.05) (effect size≥0.83), Paired T-test was used to compare within-group changes after performing myofascial release and electrotherapy (p ≤ 0.023) (effect size≥0.56), and the GLM Anova test was used to Comparison of Changes in the Elastic Modulus of the Lumbar Spine and Low Back Pain between-group (F (10,21) = 12.10, P < 0.0005) (effect size = 0.86). CONCLUSION: The improvements in the outcome measures suggest that lumbar myofascial release may be effective in subjects with non-specific low back pain. Data suggest that the elastic modulus of lumbar fascia and the severity of low back pain are directly linked. Decreasing the elastic modulus after myofascial release can directly affect reducing low back pain.

Extraction of instantaneous changes in arterial walls with sequential ultrasound images.

PURPOSE: Many structural and dynamic properties of the arterial wall, e.g., lumen diameter and wall thickness, can be measured with non-invasive ultrasound techniques. We present a new computerized analysis method for measurement of instantaneous changes in far and near arterial walls in sequential ultrasound images. METHODS: In this method, two algorithms, i.e., maximum gradient and dynamic programming, were composed and implemented. Reference points and cost function were based on dynamic programming and maximum gradient, respectively. To evaluate this method, B-mode abdominal aorta ultrasound examinations were obtained for ten New Zealand White rabbits. Approximately 70 sequential ultrasound images spanning three cardiac cycles were analyzed from each examination to detect instantaneous changes in the far and near walls and lumen diameter of rabbit abdominal aorta. The maximum, minimum, and mean diameters extracted by the automated method were compared with the same parameters measured by manual tracing. RESULTS: There was no significant differences between the manual and automated methods according to paired t test analysis (p > 0.05). In a verification study, the correlation between the two methods was calculated (R (2) = 0.98, p < 0.05). Agreement between the automated and manual methods as determined by the Bland-Altman approach was excellent. CONCLUSION: It is concluded that the new computerized analysis method is a reliable technique to assess instantaneous changes in the rabbit arterial wall in sequential B-mode images. The variability between different laboratories will be reduced if the same analysis program is used. By using this method, not only was variation in the results of manual tracing by several observers eliminated, but the duration of image processing was also considerably reduced.

Stress distribution analysis in healthy and stenosed carotid artery models reconstructed from in vivo ultrasonography.

PURPOSE: This study investigated the accuracy of models reconstructed from ultrasound image processing by comparing the radial displacement waveforms of a subject-specific artery model and evaluated stress changes in the proximal shoulder, throat, and distal shoulder of the plaques depending on the degree of carotid artery stenosis. METHODS: Three groups of subjects (healthy and with less than 50% or more carotid stenosis) were evaluated with ultrasonography. Two-dimensional transverse imaging of the common carotid artery was performed to reconstruct the geometry. A longitudinal view of the same region was recorded to extract the Kelvin viscoelastic model parameters. The pulse pressure waveform and the effective pressure of perivascular tissue were loaded onto the internal and external walls of the model. Effective, circumferential, and principal stresses applied to the plaque throat, proximal shoulder, and distal shoulder in the transverse planes were extracted. RESULTS: The radial displacement waveforms of the model were closely correlated with those of image processing in all three groups. The mean of the effective, circumferential, and principal stresses of the healthy arteries were 15.01±4.93, 12.97±5.07, and 12.39±2.86 kPa, respectively. As stenosis increased from mild to significant, the mean values of the effective, circumferential, and first principal stresses increased significantly (97%, 74%, and 103% at the plaque throat, respectively) (P<0.05). The minimum effective stress was at the lipid pool. The effective stress in calcified areas was higher than in other parts of the artery wall. CONCLUSION: This model can discriminate differences in stresses applied to mildly and severely stenotic plaques.