Ultrasound in medicine & biology
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Hibernating myocardium is viable myocardium that recovers after revascularization. The observation of loss of contractile proteins (myofibrils) and accumulation of glycogen in hibernating cardiomyocytes provide the basis for diagnosing hibernating myocardium. ⋯ Acoustic microscopy of normal cardiomyocytes showed intracellular linear echoes suggestive of myofibrils, and cardiomyocytes of hibernating myocardium revealed absence of myofibrils and dense intracellular echoes that corresponded to glycogen accumulation on optical microscopy. This modality of visualization allows a definitive diagnosis of hibernating myocardium.
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Ultrasound Med Biol · May 2004
Evaluation of vertebral artery hypoplasia and asymmetry by color-coded duplex ultrasonography.
Distinguishing stenosis and hypoplasia of the extracranial vertebral artery (VA) is clinically important, but there is no agreement in defining VA hypoplasia. We endeavored to attain reference values for VA flow volume by color Doppler ultrasonography (CDU), analyze age and gender effects on VA flow volume and develop a definition of VA hypoplasia. CDU was performed in 447 subjects free of cerebrovascular diseases or carotid stenosis. ⋯ We defined hypoplasia as a significant decrease in flow velocities and increase in RI for VA diameters < 0.22 cm. This definition is supported by findings of an increase in ipsilateral flow resistance (RI >/= 0.75), contralateral diameter (side-to-side diameter difference >/= 0.12 cm), and flow volume (side-to-side flow volume ratio >/= 5). This definition and these reference values may lead to better differentiation between congenital variation and steno-occlusion clinically.
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Ultrasound Med Biol · May 2004
Enhancement of needle visibility in ultrasound-guided percutaneous procedures.
The visibility of a needle in ultrasound (US)-guided percutaneous procedures is often limited by dispersion of the needle's reflections away from the probe. A needle enhancement algorithm is developed that maximizes the received reflections by steering the US beam precisely perpendicular to the needle. The resulting image clearly depicts the needle as a bright line. ⋯ Implementation of the needle-enhancement algorithm was made possible by using the programmable ultrasound platform and interface library (PUPIL). PUPIL is capable of acquiring digital images, processing the images in real-time, controlling the beam angle, and displaying the fused image. The results demonstrate significantly improved needle visibility in both breast phantoms and turkey breast samples.