Hitachi Medical Corporation

Koji Tanabe

Satoshi Tamano

Kageyoshi Katakura

Hiroshi Kanda

Hisashi Nishiyama

Shizuo Ishikawa

Toshio Ogawa

Shinichiro Umemura

Ryuichi Shinomura

Ryuuichi Shinomura

Hideki Nagata

An ultrasonic Doppler blood flow measuring apparatus comprises a plurality of frame memories for storing information pieces about a blood flow speed in a unit of frame, circuits for comparing blood flow speed information pieces at corresponding addresses on the plurality of frame, memories and determining a speed difference, a circuit for comparing the speed difference with a predetermined threshold value and determining a blood flow at the corresponding address as an arterial flow when the speed difference exceeds the threshold value but as a venous flow when the speed difference is below the threshold value, and a circuit for displaying the determined arterial and venous flows in different colors.

Ultrasonic doppler blood flow measuring apparatus

In ultrasonotomography, ultrasonic transducers are divided in the scanning direction and in a direction (elevation direction) orthogonal to the scanning direction and by changing the aperture in the elevation direction through focus in elevation direction, a tomogram and a Doppler signal of a blood flow can be obtained and displayed two-dimensionally. Doppler data is obtained by effecting slight angle scan of the ultrasonic beam mechanically or electronically in the elevation direction. Data pieces for the same raster of a plurality of Doppler data pieces obtained through the slight angle scan in the elevation direction are added/averaged or added to improve the S/N ration. By effecting the slight angle scan of the ultrasonic beam in the elevation direction orthogonal to a tomogram plane, a vessel at a position deviant form the tomogram plane can be found. Also, by virtue of the variable aperture in elevation direction and the function of focus in elevation direction, the resolution of tomogram in the orthogonal direction can be improved to promote the intensity of signal. In addition, by adding/averaging or adding blood flow signals, the S/N ratio can be improved.

Ultrasonotomography

An ultrasonic flow mapping apparatus transmits and reflects waves from sampling points on a two-dimensional cross-section. The waves are detected while transmitting repeatedly ultrasonic pulses. The phase shifts of different reflected waves are calculated, and displayed in color to show a distribution of blood flow velocity. Artifact due to reflected waves from body organs, which remain even by using MTI filters, is detected from phase signals, which have not passed through the MTI filters, and the artifact is removed by lowering display brightness for a sampling point corresponding to a relevant detection output.

Apparatus for ultrasonic color flow mapping

A flow meter, in which pulsed continuous ultrasonic wave is transmitted towards an object at predetermined intervals T to obtain a phase vector from a reception signal of wave reflected by the object and which calculates a Doppler frequency from the average value of phase differences between phase vectors at the sampling interval T to obtain a signal indicating the speed of the object, comprising a phase difference calculator by the auto-correlation method, by which a plurality of phase difference vectors indicating phase differences between phase vectors are added, the argument of the sum vector thus obtained representing the average phase difference, or a phase difference calculator by the 2-axial-component method, by which a phase difference is divided into 2 axial components, a cosine value and a sine value, and the average phase difference is obtained by using the average value for each of the components, and a phase difference calculator by the phase difference averaging calculator, by which a plurality of phase differences are added, as they are, to obtain the average thereof, in order to obtain a phase difference average value having small errors by switching them.

Ultrasonic doppler flow meter

Growing community of inventors

Kashiwa, Japan

Koji Tanabe