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Objectives: Bacterial infection following spinal fusion is a major clinical concern with up to 20% incidence. An ultrasound-triggered bulk-release system to combat postsurgical bacterial survival was designed and evaluated., Methods: Polylactic acid (PLA) clips were loaded with vancomycin (VAN) and microbubbles (Sonazoid, GE HealthCare) in vitro. Stability was determined over 14 days. VAN-loaded clips were submerged in water and insonated using a Logiq E10 scanner (GE HealthCare) with a curvilinear C6 probe. Doppler-induced VAN release was quantified using spectrophotometry. For in vivo testing, clips were loaded with methylene blue (MeB) solution and Sonazoid. These clips were implanted into a rabbit along the spine at L2 and L5, as well as a pig at L1 and L3, then insonated in Doppler mode using the C6 probe., Results: Sonazoid microbubbles were better preserved when incubated in VAN compared with distilled water at 4°C, 25°C, and 37°C incubation temperatures (P = .0131). Contrast enhancement was observed from both solutions when incubated at 4°C storage conditions. Insonated clips achieved average cumulative VAN release of 101.8 ± 2.8% (81.4 ± 2.8 mg) after 72 hours. Uninsonated clips had only 0.3 ± 0.1% (0.3 ± 0.1 mg) average cumulative VAN release (P < .0001). Clips retrieved from the rabbit did not rupture with insonation nor produce MeB staining of surrounding tissues. In the pig, the PLA film was visibly ruptured and MeB tissue was observed following insonation, whereas the uninsonated clip was intact., Conclusion: These results demonstrate ultrasound-triggered release of an encapsulated prophylactic solution and provide an important proof-of-concept for continuing large animal evaluations for translational merit., (© 2023 The Authors. Journal of Ultrasound in Medicine published by Wiley Periodicals LLC on behalf of American Institute of Ultrasound in Medicine.)

Purpose: Left ventricular assist device (LVAD) support is associated with peripheral vascular abnormalities beyond those associated with heart failure (HF). These abnormalities are associated with persistent functional impairments that adversely impact quality of life (QoL). Methods for measuring peripheral vascular function in this population are needed., Methods: This pilot study investigated the use of contrast-enhanced ultrasound (CEUS) using standardized protocols to estimate changes in peripheral (quadriceps) muscle perfusion among patients with HF (INTERMACS profile 3) undergoing LVAD implantation (n = 7). Patients were then stratified by those who did ("responders", n = 4) and did not ("nonresponders", n = 3) report QoL improvement with LVAD support., Results: Serial measurements obtained preoperatively and 3 months following LVAD implantation showed no significant change (P > .23) in muscle perfusion by all CEUS-based measures at rest or with an exercise stimulus for the overall population. Responders exhibited improved muscle perfusion at rest (P = .043) and decreased time to peak contrast enhancement (P = .010) at 3 months compared with baseline, suggesting improved delivery of blood to the extremities post-LVAD. Nonresponders showed unchanged resting muscle perfusion (P > .99), time to peak contrast enhancement (P = .59), and response to exercise stimulus (P > .99) following LVAD therapy., Conclusion: Our findings suggest that CEUS evaluation is a promising noninvasive, quantitative modality for real-time assessment of peripheral vasculature and muscle perfusion as an indication of treatment response in LVAD recipients and that this modality may capture perfusion measures important to QoL following LVAD implantation., (© 2021 American Institute of Ultrasound in Medicine.)

Objectives: This pilot study evaluated whether contrast-enhanced subharmonic imaging (SHI) could be used to characterize adnexal masses before surgical intervention., Methods: Ten women (with 12 lesions) scheduled for surgery of an ovarian mass underwent an SHI examination of their adnexal region using a modified LOGIQ E9 scanner (GE Healthcare, Waukesha, WI) with an endocavitary transducer, in which digital clips were acquired by pulse destruction-replenishment SHI across the lesions. Time-intensity curves were created offline to quantitatively evaluate SHI parameters (fractional tumor perfusion, peak contrast intensity, time to peak contrast enhancement, and area under the time-intensity curve), which were compared to pathologic characterizations of the lesions., Results: Of the 12 masses, 8 were benign, and 4 were malignant. A qualitative analysis of the SHI images by an experienced radiologist resulted in diagnostic accuracy of 70%, compared to 56% without contrast, whereas an inexperienced radiologist improved from 50% to 58% accuracy, demonstrating the benefit of SHI. A quantitative analysis of SHI parameters produced diagnostic accuracy as high as 81%. Peak contrast intensity was significantly greater in malignant than benign masses (mean ± SD, 0.109 ± 0.088 versus 0.046 ± 0.030 arbitrary units; P = .046). Malignant masses also showed significantly greater perfusion than benign masses (24.79% ± 25.34% versus 7.62% ± 6.50%; P = .045). When the radiologist reads were combined with the most predictive quantitative SHI parameter (percent perfusion), diagnostic accuracy improved to 84% for the experienced radiologist and 96% for the novice radiologist., Conclusions: Results indicate that SHI for presurgical characterization of adnexal masses may improve the determination of malignancy and diagnostic accuracy, albeit based on a small sample size., (© 2019 by the American Institute of Ultrasound in Medicine.)

Objectives: Hypoxic cancer cells have been shown to be more resistant to radiation therapy than normoxic cells. Hence, this study investigated whether ultrasound (US)-induced rupture of oxygen-carrying microbubbles (MBs) would enhance the response of breast cancer metastases to radiation., Methods: Nude mice (n = 15) received stereotactic injections of brain-seeking MDA-MB-231 breast cancer cells into the right hemisphere. Animals were randomly assigned into 1 of 5 treatment groups: no intervention, 10 Gy radiation using a small-animal radiation research platform, nitrogen-carrying MBs combined with US-mediated MB rupture immediately before 10 Gy radiation, oxygen-carrying MBs immediately before 10 Gy radiation, and oxygen-carrying MBs with US-mediated MB rupture immediately before 10 Gy radiation. Tumor progression was monitored with 3-dimensional US, and overall survival was noted., Results: All groups except those treated with oxygen-carrying MB rupture and radiation had continued rapid tumor growth after treatment. Tumors treated with radiation alone showed a mean increase in volume ± SD of 337% ± 214% during the week after treatment. Tumors treated with oxygen-carrying MBs and radiation without MB rupture showed an increase in volume of 383% ± 226%. Tumors treated with radiation immediately after rupture of oxygen-carrying MBs showed an increase in volume of only 41% ± 1% (P = 0.045), and this group also showed a 1 week increase in survival time., Conclusions: Adding US-ruptured oxygen-carrying MBs to radiation therapy appears to delay tumor progression and improve survival in a murine model of metastatic breast cancer., (© 2019 by the American Institute of Ultrasound in Medicine.)