Search Results (333)

The unique properties of phthalocyanines (Pcs), such as strong absorption, high photostability, effective singlet oxygen generation, low toxicity and biocompatibility, versatile chemical modifications, broad spectrum of antimicrobial activity, and synergistic effects with other treatment modalities, make them a preferred superior sensitizer in the field of antimicrobial photodynamic therapy. The photodynamic and sonodynamic activity of 3-(3-(diethylamino)phenoxy)propanoxy substituted silicon(IV) Pc were evaluated against bacteria and cancer cells. Stability and singlet oxygen generation upon light irradiation and ultrasound (1 MHz, 3 W) were assessed with 1,3-diphenylisobenzofuran. The phthalocyanine revealed high photostability in DMF and DMSO, although the singlet oxygen yields under light irradiation were low. On the other hand, the phthalocyanine revealed excellent sonostability and caused a high rate of DPBF degradation upon excitation by ultrasounds at 1 MHz. The silicon phthalocyanine presented significant bacterial reduction growth, up to 5 log against MRSA and S. epidermidis upon light excitation, whereas the sonodynamic effect was negligible. The phthalocyanine revealed high activity in both photodynamic and sonodynamic manner toward hypopharyngeal tumor (FaDu, 95% and 42% reduction, respectively) and squamous cell carcinoma (SCC-25, 96% and 62% reduction, respectively). The sensitizer showed ca. 30% aldehyde dehydrogenase inhibition in various concentrations and up to 85% platelet-activating factor acetylhydrolase for 0.25 μM, while protease-activated protein C was stimulated up to 66% for 0.75 μM. Full article

Coronary artery disease (CAD) is the third leading cause of disability and death globally. Intravascular ultrasound (IVUS) is the most commonly used imaging modality for the characterization of vulnerable plaques. The development of novel intravascular imaging and therapy devices requires dedicated open systems (e.g., for pulse sequences for imaging or thrombolysis), which are not currently available. This paper presents the development of a novel multifunctional FPGA-based pulser/receiver system for intravascular ultrasound imaging and therapy research. The open platform consists of a host PC with a Matlab-based software interface, an FPGA board, and a proprietary analog front-end board with state-of-the-art electronics for highly flexible transmission and reception schemes. The main features of the system include the capability to convert arbitrary waveforms into tristate bipolar pulses by using the PWM technique and by the direct acquisition of raw radiofrequency (RF) echo data. The results of a multicycle excitation pulse applied to a custom 550 kHz therapy transducer for acoustic characterization and a pulse-echo experiment conducted with a high-voltage, short-pulse excitation for a 19.48 MHz transducer are reported. Testing results show that the proposed system can be easily controlled to match the frequency and bandwidth required for different IVUS transducers across a broad class of applications. Full article

Medical phantoms are essential to imaging calibration, clinician training, and the validation of therapeutic procedures. However, most ultrasound phantoms prioritize acoustic realism while neglecting the viscoelastic and anisotropic properties of fibrous soft tissues. This gap limits their effectiveness in modeling realistic biomechanical behavior, especially in wave-based diagnostics and therapeutic ultrasound. Current materials like gelatine and agarose fall short in reproducing the complex interplay between the solid and fluid components found in biological tissues. To address this, we developed a soft, anisotropic composite whose dynamic mechanical properties resemble fibrous biological tissues such as skin and skeletal muscle. This material enables wave propagation and vibration studies in controllably anisotropic media, which are rare and highly valuable. We demonstrate the tunability of damping and stiffness aligned with fiber orientation, providing a versatile platform for modeling soft-tissue dynamics and validating biomechanical simulations. The phantoms achieved Young’s moduli of 7.16–11.04 MPa for skin and 0.494–1.743 MPa for muscles, shear wave speeds of 1.51–5.93 m/s, longitudinal wave speeds of 1086–1127 m/s, and sound absorption coefficients of 0.13–0.76 dB/cm/MHz, with storage, loss, and complex moduli reaching 1.035–6.652 kPa, 0.1831–0.8546 kPa, and 2.138–10.82 kPa. These values reveal anisotropic response patterns analogous to native tissues. This novel natural fibrous composite system affords sustainable, low-cost ultrasound phantoms that support both mechanical fidelity and acoustic realism. Our approach offers a route to next-gen tissue-mimicking phantoms for elastography, wave propagation studies, and dynamic calibration across diverse clinical and research applications. Full article

Ultrasound attenuation imaging (ATI) is a non-invasive method for quantifying hepatic steatosis, offering advantages over the hepatorenal index (HRI). However, its reliability can be influenced by factors such as measurement depth, ROI size, and subcutaneous fat. This paper examines the impact of these confounders on ATI measurements and discusses diagnostic considerations. In this study, 33 healthy adults underwent liver ultrasound with ATI and HRI protocols. ATI measurements were taken at depths of 2–5 cm below the liver capsule using small and large ROIs. Two operators performed the measurements, and inter-operator variability was assessed. Subcutaneous fat thickness was measured to evaluate its influence on attenuation values. The ATI measurements showed a consistent decrease in attenuation coefficient values with increasing depth, approximately 0.05 dB/cm/MHz. Larger ROI sizes increased measurement variability due to greater anatomical heterogeneity. HRI values correlated weakly with ATI and were influenced by operator technique and subcutaneous fat, the latter accounting for roughly 2.5% of variability. ATI provides a quantitative assessment of hepatic steatosis compared to HRI, although its accuracy can vary depending on the depth and ROI selection. Standardised imaging protocols and AI tools may improve reproducibility and clinical utility, supporting advancements in ultrasound-based liver diagnostics for better patient care. Full article

Background: Gallbladder hypomotility is a key pathogenic factor in cholelithiasis. Non-invasive interventions to enhance gallbladder contractility remain limited. Ultrasound therapy has shown promise in various muscular disorders, but its effects on gallbladder function are unexplored. Methods: This study employed low-intensity pulsed ultrasound (LIPUS) at a 3 MHz frequency and 0.8 W/cm² intensity with a 20% duty cycle to irradiate the gallbladder region of fasting guinea pigs. Gallbladder contractile function was evaluated through multiple complementary approaches: in vivo assessment via two-dimensional/three-dimensional ultrasound imaging to monitor volumetric changes; quantitative functional evaluation using nuclear medicine scintigraphy (^99mTc-HIDA); and ex vivo experiments including isolated gallbladder muscle strip tension measurements, histopathological analysis, α-smooth muscle actin (α-SMA) immunohistochemistry, and intracellular calcium fluorescence imaging. Results: Ultrasound significantly enhanced gallbladder emptying, evidenced by the volume reduction and increased ejection fraction. Scintigraphy confirmed accelerated bile transport in treated animals. Ex vivo analyses demonstrated augmented contractile force, amplitude, and frequency in ultrasound-treated smooth muscle. Histological examination revealed smooth muscle hypertrophy, α-SMA upregulation, and elevated intracellular calcium levels. Extended ultrasound exposure produced sustained functional improvements without tissue damage. Conclusions: Ultrasound effectively enhances gallbladder contractile function through mechanisms involving smooth muscle structural modification and calcium signaling modulation. These findings establish the experimental foundation for ultrasound as a promising non-invasive therapeutic approach to improve gallbladder motility and potentially prevent gallstone formation. Full article

Superficial venous aneurysms of the upper extremities are a rare clinical entity, often underdiagnosed and misinterpreted as other soft tissue masses. We present the case of a 28-year-old male patient with a subcutaneous mass on the dorsum of the left hand, diagnosed as a superficial venous aneurysm by high-resolution ultrasound using a probe bandwidth of up to 18 MHz, unchanged at three-month Doppler-ultrasound examination. This case highlights the fundamental role of high-frequency ultrasound in the differential diagnosis and conservative management of such lesions. Full article

Transcranial focused ultrasound (TcFUS) neuromodulation is hindered by skull-induced acoustic limitations. To enable synergistic multi-region brain stimulation, we designed non-coaxial multi-focal composite Fresnel acoustic lenses, including an overlapping Fresnel lens (OFL) and an alternating-segmented Fresnel lens (ASFL). These lenses convert planar ultrasound into multiple foci. Based on Fresnel theory, acoustic fields were analyzed via simulations and experiments, validating the generation of four non-coaxial foci (10/30 mm focal lengths) from a 1 MHz planar wave using both OFL and ASFL. The influence of lens parameters on focal pressure distribution was investigated, and morphology was quantified using a linear least-squares method. Significant differences in focal morphology and intensity between OFL and ASFL provide crucial guidance for optimizing multi-target TcFUS strategies. Full article

Background/Objective: Transcutaneous Doppler ultrasound is a fundamental tool in evaluating carotid stenosis cross-sectional severity (CS-CSS) in clinical practice because peak-systolic and end-diastolic velocities (PSV, EDV) increase with angiographic diameter stenosis. We tested the hypothesis that lesion length (LL) may affect PSV and EDV. Methods: CARUS (Carotid Artery IntravasculaR Ultrasound Study) prospectively enrolled 300 consecutive patients (age 47–83 years, 64.3% men, 63.3% symptomatic) with carotid stenosis ≥50% by Doppler ultrasound considered diagnostic (corelab analyst). We correlated stenosis LL (mm) and minimal lumen area (MLA, mm²) with PSV and EDV. Results: IVUS imaging (20 MHz Volcano/Philips) was uncomplicated. As IVUS probe forward/backward movement with systole/diastole (“jumping”-related artifact superimposed on motorized pullback) restrained LL (but not MLA) determination, LL measurement was angiographic. Final data set included 293 patients/stenoses (applicable to seven angiograms unsuitable for LL measurement). Irrespective of CS-CSS, a significant LL effect on PSV and EDV occurred with LL ≥ 7 mm (n = 224/293, i.e., 76.5% study patients/lesions; r = 0.38 and r = 0.35); for MLA irrespective of CS-CCS the coefficients were r = 0.49 (PSV) and r = 0.42 (EDV); p < 0.001 for all. For LL and MLA considered together, the correlations were stronger: r = 0.61 (PSV) and r = 0.54 (EDV); p < 0.0001 for both. Combined LL and MLA effect was represented by the following formulas: PSV = 0.31 × LL/MLA + 2.02 [m/s]; EDV = 0.12 × LL/MLA + 0.63 [m/s], enabling to correct the PSV (EDV)-based assessment of CS-CSS for the LL effect. Conclusions: This study provides, for the first time, systematic evidence that the length of carotid stenosis significantly affects lesional Doppler velocities. We established formulas incorporating the contribution of both stenosis length and its cross-sectional severity to PSV and EDV. We advocate including stenosis length measurement in duplex ultrasound reports when performing PSV (EDV)-based assessment of carotid cross-sectional stenosis severity. Full article

Background: The superficial vessel system in the lower abdomen, including the superficial circumflex iliac artery (SCIA) and superficial inferior epigastric artery (SIEA), is widely used in reconstructive microsurgery. Preoperative ultrasonography, particularly ultra-high-frequency ultrasound (UHFUS), enhances surgical planning by providing high-resolution imaging. This study aimed to utilize UHFUS to examine the SCIA, SCIV, SIEA, and SIEV for reconstructive surgery planning. Methods: This prospective study included 25 patients undergoing free DIEP flap breast reconstruction. Patients with horizontal lower abdominal scars were excluded. Preoperative UHFUS, using a 48 MHz transducer, was performed to map and measure the superficial branch of SCIA (sSCIA), SCIV, SIEA, and SIEV. The vessel location, diameter, depth, and course were documented and analyzed. Results: Twenty-five female patients (50 hemiabdomens) aged 41 to 66 were included. The mean BMI was 21.6 kg/m² (range: 18.4–30.4 kg/m²). At the ASIS level, the mean diameter of the sSCIA, SIEA, SCIV, and SIEV were 0.76 mm, 0.63 mm, 1.72 mm, and 2.18 mm, respectively. A superior lateral pedicle course was observed in 98% of the sSCIA. All patients had at least one detectable superficial artery, with 96% showing detectable arteries on both sides of the lower abdomen. Conclusions: UHFUS effectively maps superficial vessels in the lower abdomen for reconstructive surgery. The SCIA and SCIV are reliably detectable, while the SIEA is less consistently identified. UHFUS enhances flap design by providing precise vessel localization and sizing, leading to safer and more efficient surgeries. Full article

Objective: In previous studies, echogenic liposomes with liquid and gas cores were analyzed as alternative carriers of drug molecules and cavitation nuclei for sonoporation. The possibility of small interfering RNA (si-RNA) encapsulation has also been presented. In this study, the usability of echogenic liposomes as drug carriers and cavitation seeds was evaluated using an in vivo model. Methods: A doxorubicin-loaded echogenic liposome was synthesized as a drug carrier. The size distribution and the number of formed echogenic liposomes were measured. Five comparative in vivo experiments were conducted with and without doxorubicin-loaded echogenic liposomes, and the results were statically analyzed. Results: Sonoporation with doxorubicin-loaded echogenic liposomes at 3.05 W/cm² of ISPTA ultrasound sonication and 0.98 MHz results in an average tumor volume growth of less than 25% of that following the simple administration of doxorubicin. Considering the p-value between the two groups is approximately 0.03, doxorubicin-loaded echogenic liposomes were effectively applicable as cavitation nuclei for sonoporation. Conclusions: Although further studies are needed to clarify the responses to incident ultrasound fields, the proposed echogenic liposome appears to be a promising alternative cavitation nuclei/carrier for sonoporation. Full article

The process of ultrasonic atomization involves a series of dynamic/topological deformations of free surface, though not always, of a bulk liquid (initially) below the air. This study focuses on such dynamic interfacial alterations realized by changing some acousto-related operating conditions, including ultrasound excitation frequency, acoustic strength or input power density, and the presence/absence of a “stabilizing” nozzle. High-speed, high-resolution imaging made it possible to qualitatively identify four representative transitions/demarcations: (1) the onset of a protrusion on otherwise flat free surface; (2) the appearance of undulation along the growing protuberance; (3) the triggering of emanating beads fountain out of this foundation-like region; and (4) the induction of droplets bursting and/or mist spreading. Quantitatively examined were the two-parameters specifications—on the degrees as well as induction—of the periodicity in the protrusion-surface and beads-fountain oscillations, detected over wider ranges of driving/excitation frequency (0.43–3.0 MHz) and input power density (0.5–10 W/${\mathrm{c}\mathrm{m}}^2$) applied to the ultrasound transducer of flat surface on which the nozzle was either mounted or not. The resulting time sequence of images processed for the extended operating ranges, regarding the fountain structure pertaining, in particular, to recurring beads, confirms the wave-associated nature, i.e., their size “scalability” to the ultrasound wavelength, predictable from the traveling wave relationship. The thresholds in acoustic conditions for each of the four transition states of the fountain structure have been identified—notably, the onset of plausible “bifurcation” in the chain-beads’ diameter below a critical excitation frequency. Full article

(1) Background: Patellar and Achilles tendon injuries have become increasingly prevalent, particularly among active populations and athletes, leading to significant functional impairments. While B-Mode ultrasound has been useful in the diagnosis of these injuries, its capacity to assess tendon mechanical properties, such as stiffness, is limited. Shear wave elastography (SWE) offers a promising alternative by measuring tissue stiffness, which may enhance the evaluation of tendon health. Previous studies have established that SWE can differentiate healthy tendons from those with pathological changes. However, reference values for specific tendon types, including the patellar and Achilles tendons, remain limited. This study aims to provide preliminary baseline SWE values for these tendons in a healthy cohort. (2) Methods: In this cross-sectional study, healthy volunteers aged 18–65, with no history of lower extremity injury, were assessed using a Samsung RS85 Prestige ultrasound system with a 14L-2 MHz transducer. SWE measurements were obtained from the patellar tendon at a single location and from the Achilles tendon at both the midportion and insertional sites. All assessments followed a standardized protocol to ensure consistency and minimize variability. (3) Results: A total of 54 healthy adult participants were included. The mean SWE value for the patellar tendon was 96.3 (SD = 10.9 kPa), with males showing significantly higher stiffness than females (99.3 kPa vs. 93.8 kPa, p = 0.009). A higher BMI was associated with lower stiffness in the patellar tendon. The mean SWE values for the Achilles tendon were 101.7 (SD = 16.2 kPa) at the insertion and 145.6 (SD = 18.8 kPa) at the midportion. (4) Conclusions: This study provides SWE values for the patellar and Achilles tendons in healthy individuals, which can serve as a foundation for future research and clinical applications. These values may help in the comparison of healthy and pathological tendons, particularly in the context of tendinopathies, tendon tears, and treatment monitoring. While shear wave elasticity shows promise as a tool for diagnosing and monitoring tendon injuries and degeneration, more research is required to establish its precise reliability and validity in clinical practice. Full article

Ultrasound is one of the most promising methods for blood pressure monitoring due to its harmless, non-invasive, and high-precision characteristics. To further enhance the biocompatibility of ultrasound blood pressure monitors, this work reports wearable ultrasonic patches for blood pressure monitoring based on lead-free KNN (potassium sodium niobate)-based materials. The patches are designed and fabricated with a center frequency of 5 MHz and dimensions of 2.8 mm × 2.8 mm, optimized for both electrical impedance matching and vascular detection. Moreover, biocompatible silicone rubber is used for the packaging. The wearable ultrasonic patches are demonstrated to effectively transmit and receive signals. The diameter of artificial blood vessels is measured to validate the vascular diameter detection capability of the patches. The relationship between blood pressure and vascular diameter is then calculated. A radial artery vascular system platform is built to simulate changes in human blood pressure. Finally, the patches are shown to successfully measure the variation in vessel diameters on this platform. These patches exhibit sufficient detection ability, good biocompatibility, and can adhere tightly to human skin without coupling agents, providing the possibility for safe, sustainable, comfortable, and wearable long-term blood pressure monitoring. Full article

In this study, we have developed an optical fiber ultrasound emitter based on the thermal cavitation effect. A tube filled with a highly absorptive liquid is sealed at the end of an optical fiber pigtail. A continuous-wave laser is transmitted through the fiber, heating the highly absorptive copper salt solution near the fiber end face to its spinodal limit. Using a single-mode fiber, we achieved ultrasound pulses with an amplitude of 330 kPa and a repetition rate of 4 kHz in the frequency range of 5–17 MHz, and a bandwidth of 12 MHz was obtained by using a low laser heating power of 52 mW at a wavelength of 974 nm. This optical fiber ultrasound emitter features a simple fabrication process, low cost, and low optical power consumption. Its flexible design allows for easy integration into medical devices with small dimensions and makes it suitable for non-destructive testing in confined spaces. Full article

Background: Rutin is a natural flavonoid extracted primarily from plants with anti-inflammatory and antioxidant properties, and it is highly valuable in the cosmetics industry. However, the poor transdermal permeability of rutin limits its application via transdermal administration. Previous studies have predominantly focused on chemical methods for enhancing penetration. This study investigated the potential of ultrasound as a physical method by which to augment the transdermal absorption and anti-inflammatory effects of rutin. Method: Through in vitro diffusion experiments, we analyzed the effects of the ultrasonic frequency and intensity on percutaneous absorption. The optimal ultrasound parameters were determined based on the intradermal retention rate, which is defined as the proportion of intradermal retention to the total penetration. Parameters with higher retention rates were considered optimal. To validate the anti-inflammatory efficacy of rutin delivered using the ultrasound-assisted method, we employed a tape-stripping technique to induce inflammation in BALB/c nude mice. Eight mice were assigned to each treatment group: (A) self-repair (control group), (B) regular rutin treatment, and (C) ultrasound-assisted treatment. Results: The research findings indicate that ultrasound frequency and intensity of 1 MHz and 0.2 W/cm², as well as 3 MHz and 0.2 W/cm², result in the maximum proportion of rutin intradermal retention, exhibiting values 1.8 times (using porcine skin) and 2.63 times (using nude mouse skin) higher than those achieved without ultrasound, respectively. Group C showed the shortest recovery time and displayed complete skin barrier function restoration by the fourth day $(p<0.05)$, whereas group A exhibited the slowest recovery. Conclusions: This study offers an innovative approach for the transdermal delivery of rutin to facilitate skin barrier function repair. Full article