Multigate Quality Doppler Profiles Technology in Vascular, Obstetrics and Cardiology Applications

Abstract

Multigate Quality Doppler Profiles (QDP) is a Fast Fourier Transform (FFT) -based Doppler technology recently integrated within a commercial ultrasound scanner. QDP represents a novel analysis tool, which is able to simultaneously detect and show the velocity components, present in the blood flow of multiple vessels, without any frame rate reduction. QDP can be used in conjunction with the DIR algorithm to enhance the visibility of the flow direction information. The present work describes the use of QDP in Cardiology (Pediatric and Adult), Vascular (cervical venous and arterial system) and Obstetrics (uterine arteries). In vivo and in vitro tests are reported, showing the QDP behavior with respect to insonation angle changes and its advantages with respect to classic Doppler technologies. The QDP is demonstrated to be a precise positioning tool for the Pulsed Wave Doppler (PW) sample volume (SV) and a qualitative direct real time indicator of blood flow variations. It is also shown ideal for the study of turbulent flow, for minor reflux detection and for easier sampling of the blood flow signal within the examined vessel (or vessels) in case of movements. IntroductionQDP is a technique processing the echo signals backscattered from multiple depths along the ultrasound beam to produce and display the spectral profiles in real-time. MethodsThe QDP technology, developed by the Microelectronics Systems Design Laboratory of the University of Firenze (Italy), was integrated in a commercial diagnostic ultrasound scanner (MyLab30Gold, Esaote S.p.A., Italy). The QDP tool was made available with all US probes compatible with the PW modality. In particular, the probes used for the present work where: a phased array probe with frequency range 1-4 MHz (PA240, Esaote, Imaging frequencies: 2.0-2.5-3.5 MHz; Doppler frequencies: 2.0-2.5 MHz); a linear array probe with frequency range 3-11 MHz (LA332, Esaote, Imaging frequencies: 3.5-5.0-6.6-10.0 MHz; Doppler frequencies: 3.3-5.0 MHz) and a convex array probe with frequency range 1-8 MHz (CA631, Esaote, Imaging frequencies: 2.5-3.5-5.0-6.6 MHz; Doppler frequencies: 2.5-3.3 MHz). QDP is a Multigate Spectral Doppler technology that processes the echo signals backscattered from multiple depths along the US beam, producing and displaying in real-time the so-called spectral profile [6]. This is a matrix of power spectral densities corresponding to the simultaneously investigated depths. The spectral profile is obtained by calculating, through the classic Fast Fourier Transform (FFT) algorithm, the Doppler spectrum of the echo samples gathered from one depth and by repeating the procedure over 128 or 256 consecutive depths (covering a total length up to 9 cm). The QDP approach extends the known benefits of spectral analysis [7] to a large depth range without sacrificing the axial resolution. QDP technology investigates the "third dimension of Doppler" in graphical form, where spatial distribution is on the vertical axis and velocity on the horizontal one, while the brightness...

Chronic Cerebrospinal Venous Insufficiency

“…In this study, both transcranial Doppler imaging and quality Doppler profiles were used to assess for reflux in the deep cerebral veins. An Esaote Biosound MyLab 25 ultrasound machine with a PA 240 1–4‐MHz probe was used for quality Doppler profile imaging 8 . Transtemporal bone windows were used to evaluate unilateral or bilateral middle cerebral veins, the vein of Rosenthal, and/or a single vein of Galen 9 .…”

Cancellation of Doppler intrinsic spectral broadening using ultrafast Doppler imaging

“…Thus, a new manner of performing blood flow imaging was recently proposed, called ultrafast doppler imaging (UFd) [8]. In this way, complex transient turbulences can be visualized through a detailed temporal analysis with a few milliseconds of resolution [8]- [13]. By merging cFI and PW doppler into a single ultrafast doppler sequence, all of the ultrasonic data required for assessing the 2-d flow behavior is acquired, and the PW doppler information for each pixel within the wide 2-d image can be used to calculate blood flow.…”