CCDS: Optimizing instrument settings, scan techniques, and measurement procedures
While a thorough understanding of the operating characteristics of any ultrasound scanning instrument has always been important for acquiring optimal images, even with gray-scale-only units, such an understanding becomes of critical importance with the additional features provided on duplex- and color-flow Doppler scanners. A few basic considerations with regard to the scanning environment deserve mention before we begin a more detailed look at how to optimize the various CCDS scan parameters. Comfort of both the sonographer and patient is an important factor, especially when a lengthy examination is anticipated; a restless patient or a shaky hand on the transducer can render a study useless even when state-of-the-art equipment is being used. If the patient is on a scanning table or stretcher (gurney) it is important that the mattress be sufficiently thick and firm to prevent uncomfortable pressure points; supplemental use of pillows under the knees or for partial elevation of the head (if allowed by the type of study to be performed) will contribute to the patient’s ability to minimize movement. The sonographer should choose a position (whether standing or seated on an adjustable stool) which relieves rather than promotes strain. For carotid/vertebral artery studies some laboratories place the patient in an adjustable chair of the type used by dentists or barbers; the sonographer is seated behind the patient’s head, and the back of the chair is reclined to bring the neck into easy reach. This approach is particularly appreciated by patients who have difficulty breathing when fully supine.
KeywordsPulse Repetition Frequency Doppler Angle Diastolic Flow Velocity Entire Vessel Doppler Beam
Unable to display preview. Download preview PDF.
- Burns PN (1988) Interpretation and analysis of Doppler signals. Chapter 4. In: Taylor KJW, Burns PN, Wells PNT (eds) Clinical applications of Doppler ultrasound. New York, Raven PressGoogle Scholar
- Burns PN (1991) Basic Doppler principles. From the Syllabus of the advanced color Doppler ultrasonography course, American Institute of Ultrasound in Medicine, Rockville, MDGoogle Scholar
- Doppler Sonographic Imaging of the Vascular System (1991) Report of the Ultrasonography Task Force, Council on Scientific Affairs, American Medical Association. JAMA 265: 2382–2387Google Scholar
- Middleton WD (1991) Color Doppler ultrasonography: Image interpretation and optimization. From the Syllabus of the Advanced Color Doppler Ultrasonography Course, American Institute of Ultrasound in Medicine, Rockville, MDGoogle Scholar