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We evaluated the influence of settings on an ultrasound machine on the configuration of a single B-line in a healthy model and analyzed the frequency spectrum. We also devised simple experimental models that generated B-line-like artifacts and evaluated the influence of the machine settings on the configuration. Visualization of B-lines was affected by the spatial compound imaging, the focal zone and the frequency. The spectra of both the B-line and non-B-line region at the same depth had the same center frequency and bandwidth. B-line-like artifact was generated by a spindle-shaped juice sac of a mandarin orange, an edible string-shaped glucomannan gel, glass beads and glass plates. Visualization of B-line-like artifacts was also affected by these machine settings. Our study indicated that the physical basis of some B-lines is multiple reverberations. B-line-like artifacts provide clues for solving key issues, such as the physical basis of B-lines, the sonographic-pathologic correlation in B-lines and the effects of machine settings.

Surgical resection is the only treatment of colorectal liver metastases that can ensure long-term survival and cure in some patients. However, only 20% of patients are suitable for surgery. As a result, many nonresectional modalities of treatment have been assessed to provide an alternative to liver resection. Several limitations have been observed when using these techniques and available evidence is limited. Here, we report that a new design of high intensity focused ultrasound transducer can significantly enlarge the coagulated volume over short periods of time and that treatment in the liver can be guided in real-time using an integrated ultrasound imaging probe. Our long-term objective is to develop a device that can be used during surgery for eventual clinical use in conjunction with resection. Eight ultrasound emitters, divided into 256 elements, were created by sectioning a single toroid piezocomposite transducer. The focal zone was conical in shape and located 70 mm from the transducer; enabling the treatment of deep-seated tumors. A single thermal lesion was created when the eight emitters performed alternative and consecutive 5-s ultrasound exposures. This article presents in vivo evidence that the coagulated volume obtained from a 40 s total exposure in the liver was 7.0 ± 2.5 cm 3 (minimum 1.5 – maximum 20.0 cm 3 ) with an average diameter of 17.5 ± 3.8 mm (minimum 10.0 – maximum 29.0 mm). All lesions were visible with high contrast on sonograms. The correlation between the diameter of lesions observed on sonograms and during gross examination was 92%. This method also allowed the user to easily enlarge the coagulated volume by juxtaposing single lesions. This approach may have a role in treating unresectable colorectal liver metastases and may also be used in conjunction with resection to extend its limits. (E-mail: David.Melodelima@inserm.fr )

An acoustic grid for rapid measurement of the spatial resolution of colour velocity images is described. The grid is composed of alternate widths of acoustic window and acoustic attenuator. Attenuation is provided by the use of a layer of waterproof paper, which is wrapped in close contact with a tube of a flow phantom. The colour image consists of several closely spaced lines. When the grid line spacing is less than the spatial resolution, the colour lines cannot be separately visualised. The use of several grids of different spacing provides a measure of the spatial resolution. It is shown that the spatial resolution is dependent on the position of the focal zone.

An investigation of the outcome of over 1600 breast ultrasound examinations revealed a number of scanning artifacts. Artifactual echoes in cysts resulted from inappropriate scanning factors, including focal zone placement, gain, TGC, and gray scale, and from partial volume effect. The absence of a sign suspicious for carcinoma, posterior shadowing to a solid mass,resulted from faulty focal zone placement, or from the mass resting on chest wall tissue. Pathology was sometimes simulated by postsurgical scars, ducts, and benign calcifications. Corrective procedures to alleviate the various scanning artifacts are recommended.