Ultrasound in medicine & biology
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Ultrasound Med Biol · Oct 2008
Comparative Study Controlled Clinical TrialDo bubble characteristics affect recanalization in stroke patients treated with microbubble-enhanced sonothrombolysis?
Administration of microbubbles (MB) may augment the effect of ultrasound-enhanced systemic thrombolysis in acute stroke. Bubble structural characteristics may influence the effect of MB on sonothrombolysis. We aimed to compare the effects of galactose-based air-filled MB (Levovist) and sulphur hexafluoride-filled MB (Sonovue) on recanalization and clinical outcome. ⋯ Forty-four percent of patients in the LV group and 48.5% in the SV group achieved functional independence (mRS
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Ultrasound Med Biol · Aug 2008
Reliability of measuring sciatic and tibial nerve movement with diagnostic ultrasound during a neural mobilisation technique.
Diagnostic ultrasound provides a technique whereby real-time, in vivo analysis of peripheral nerve movement is possible. This study measured sciatic nerve movement during a "slider" neural mobilisation technique (ankle dorsiflexion/plantar flexion and cervical extension/flexion). Transverse and longitudinal movement was assessed from still ultrasound images and video sequences by using frame-by-frame cross-correlation software. ⋯ Mean longitudinal sciatic nerve movement at the PMT was 3.47 mm (SEM +/- 0.79 mm; n = 27) compared with the PC of 5.22 mm (SEM +/- 0.05 mm; n = 3). The reliability of ultrasound measurement of transverse sciatic nerve movement was fair to excellent (Intraclass correlation coefficient [ICC] = 0.39-0.76) compared with excellent (ICC = 0.75) for analysis of longitudinal movement. Diagnostic ultrasound presents a reliable, noninvasive, real-time, in vivo method for analysis of sciatic nerve movement.
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Ultrasound Med Biol · Aug 2008
Comparative StudyLow-intensity pulsed ultrasound accelerated bone-tendon junction healing through regulation of vascular endothelial growth factor expression and cartilage formation.
The purpose of this study was to use our established partial patellectomy rabbit model to study the effects of low-intensity pulsed ultrasound (LIPUS) on patella-patellar tendon (PPT) junction repair through hypothesized pathways including regulation of vascular endothelial growth factor (VEGF) and chondrogenesis. Standard partial patellectomy was conducted in sixty-four 18 wk-old rabbits that were subsequently divided into LIPUS and control group. The PPT complex was harvested at week 2, 4, 8 and 16 postoperatively (n = 8 for each time point) for preparation of sagittal sections that were evaluated for angiogenesis by analyzing VEGF expression and chondrogenesis. ⋯ However, the specimens in the control group just showed the similar cartilaginous metaplasia region until postoperative week 8. Histomorphometry revealed thicker fibrocartilage zone and larger cartilaginous metaplasia field at PPT healing interface in LIPUS group compared with those of the control group at week 8 and 16. In conclusion, this was the first quantitative study to demonstrate that LIPUS improved B-T junction healing through regulation of VEGF expression in early healing phase and subsequent chondrogenesis.
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Gaseous microemboli can arise in extracorporeal lines and devices such as dialysis machines. They are associated with severe pulmonary side effects in patients undergoing chronic hemodialysis sessions. The goal of this study was to develop a gaseous emboli trapper using ultrasound waves to remove any air bubble from the tubing system before they reach the patient. ⋯ When the air bubble trapper was activated, a reduction of the number of MES, up to 70%, was achieved. Doppler recordings suggest that the circulating bubbles were either fragmented into smaller bubble fragments or directly got pushed into the second subchannel where they were collected. This simple approach using an ultrasound-based trapping system was shown to operate adequately with the current settings and can be used to filter air microemboli.
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Ultrasound Med Biol · Apr 2008
Evaluating tissue changes with ultrasound during radiofrequency ablation.
The purpose of this study was to estimate tissue changes during radiofrequency (RF) ablation by correlating echo frequency shifts and temperature elevations. Experiments were performed on phantoms (tissue mimicking gel) and in-vitro turkey breast. Heating was performed with a modified RF-ablation system. ⋯ In-vitro experiments showed a correlation (R(2) = 0.84) between the width of the coagulated area and the maximal width of the region with more than 0.12 MHz frequency shifts, but a lower correlation (R(2) = 0.4) between the width of the coagulated area and the temperature elevation. In conclusion, correlation was found between echo frequency shifts and temperature elevations and between echo frequency shifts and the width of the ablated area during intermittent RF ablation. Our results suggest that, with further refinement and validation, ultrasound could be used to measure RF heating and its induced coagulation.