CX50 EPIQ S8 3 Broadband Sector Ultrasound Transducer Probe

S8-3 Broadband Sector Ultrasound Transducer

1. Type:sector
2. Frequency: 8.0-3.0 MHz
3. Compatible system: CX50/EPIQ
4. Application:cardiac,fetal echo

Knowledge point

Contrast ultrasonography (ultrasound contrast imaging)

Main article: Contrast-enhanced ultrasound

A contrast medium for medical ultrasonography is a formulation of encapsulated gaseous microbubbles to increase echogenicity of blood, discovered by Dr Raymond Gramiak in 1968 and named contrast-enhanced ultrasound. This contrast medical imaging modality is clinically used throughout the world, in particular for echocardiography in the United States and for ultrasound radiology in Europe and Asia.

Microbubbles-based contrast media is administrated intravenously in patient blood stream during the medical ultrasonography examination. Thanks to their size, the microbubbles remain confined in blood vessels without extravasating towards the interstitial fluid. An ultrasound contrast media is therefore purely intravascular, making it an ideal agent to image organ microvascularization for diagnostic purposes. A typical clinical use of contrast ultrasonography is detection of a hypervascular metastatic tumor, which exhibits a contrast uptake (kinetics of microbubbles concentration in blood circulation) faster than healthy biological tissue surrounding the tumor. Other clinical applications using contrast exist, such as in echocardiography to improve delineation of left ventricle for visually checking contractibility of heart after a myocardial infarction. Finally, applications in quantitative perfusion (relative measurement of blood flow) emerge for identifying early patient response to an anti-cancerous drug treatment (methodology and clinical study by Dr Nathalie Lassau in 2011), enabling to determine the best oncological therapeutic options.

In oncological practice of medical contrast ultrasonography, clinicians use the method of parametric imaging of vascular signatures invented by Dr Nicolas Rognin in 2010. This method is conceived as a cancer aided diagnostic tool, facilitating characterization of a suspicious tumor (malignant versus benign) in an organ. This method is based on medical computational science to analyze a time sequence of ultrasound contrast images, a digital video recorded in real-time during patient examination. Two consecutive signal processing steps are applied to each pixel of the tumor:

1. calculation of a vascular signature (contrast uptake difference with respect to healthy tissue surrounding the tumor);

2. automatic classification of the vascular signature into a unique parameter, this last coded in one of the four following colors:

o green for continuous hyper-enhancement (contrast uptake higher than healthy tissue one),

o blue for continuous hypo-enhancement (contrast uptake lower than healthy tissue one),

o red for fast hyper-enhancement (contrast uptake before healthy tissue one) or

o yellow for fast hypo-enhancement (contrast uptake after healthy tissue one).

Once signal processing in each pixel is completed, a color spatial map of the parameter is displayed on a computer monitor, summarizing all vascular information of the tumor in a single image called a parametric image (see last figure of press article[as clinical examples). This parametric image is interpreted by clinicians based on predominant colorization of the tumor: red indicates a suspicion of malignancy (risk of cancer), green or yellow – a high probability of benignity. In the first case (suspicion of malignant tumor), the clinician typically prescribes a biopsy to confirm the diagnostic or a CT scan examination as a second opinion. In the second case (quasi-certain of benign tumor), only a follow-up is needed with a contrast ultrasonography examination a few months later. The main clinical benefits are to avoid a systematic biopsy (risky invasive procedure) of benign tumors or a CT scan examination exposing the patient to X-ray radiation. The parametric imaging of vascular signatures method proved to be effective in humans for characterization of tumors in the liver. In a cancer screening context, this method might be potentially applicable to other organs such as breast or prostate.

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