Systems and methods for producing an image from a rotational intravascular ultrasound device
The invention generally relates systems and methods to for producing an image from a rotational intravascular ultrasound device. A method can include alternately transmitting complementary Golay codes to a plurality of transducers in a intravascular ultrasound device; receiving echoes of the complementary codes from the transducers; performing pulse compression of the echoes that comprises weighting the received echoes and summing an odd number of weighted echoes, wherein a center echo is given a weighted value of 1.0 and weighted sums of its neighbors constitute complementary echoes of a Golay pair; and producing an image from the compressed echoes. A system can include a processor; and a plurality of beam modules coupled to the processor, each module comprising: a receiver for receiving a trigger signal from the processor; a complex programmable logic device programmed with a Golay code; a high voltage switching transmitter; and an ultrasound transducer.
1. A system for intravascular ultrasound (IVUS) imaging, the system comprising:
a rotational IVUS catheter configured to be positioned within a vessel of a patient, the rotational IVUS catheter comprising a single ultrasound transducer configured to rotate about an axis to obtain an IVUS image of the vessel; and
a processor in communication with the single ultrasound transducer, the processor configured to:
alternately transmit a first code and a second code of a pair of complementary Golay codes to the single ultrasound transducer while the single ultrasound transducer is rotating about the axis within the vessel;
receive, from the single ultrasound transducer, echo signals associated with the pair of complementary Golay codes, the received echo signals comprising a first echo signal, a second echo signal, and a third echo signal;
perform pulse compression of the received echo signals,
wherein the pulse compression comprises weighting the received echo signals and summing an odd number of weighted echo signals,
wherein the second echo signal is associated with the second code, and
wherein the first and the third echo signals neighboring the second echo signal are each associated with the first code; and
produce the IVUS image from the compressed echo signals.
2. The system of claim 1 , wherein the second echo signal comprises a weighted value of 1.0, and wherein the first and the third echo signals individually comprise a weighted value less than 1.0 such that a total weighted value of the first and the third echo signals is 1.0.
3. The system of claim 2 , wherein the weighted values of the first and the third echo signals are equal.
4. The system of claim 1 , wherein a bi-phase window is applied over the pair of complementary Golay codes.
5. The system of claim 4 , wherein the bi-phase window is one of a bi-phase rectangular window, a bi-phase Hamming window, a bi-phase Hanning window, or a bi-phase Bartlett window.
6. The system of claim 1 , wherein the processor is configured to compute a convolution of the received echo signals of the pair of complementary Golay codes.
7. The system of claim 1 , wherein the processor is coupled to a display device and causes the IVU S image to be displayed.
8. The system of claim 1 , wherein the pulse compression further comprises:
summing the first echo signal, the second echo signal, and the third echo signal to generate a first scanline; and
summing the second echo signal, the third echo signal, and a fourth echo signal to generate a second scanline, wherein the fourth echo signal is associated with the second code.
9. The system of claim 8 , wherein:
for the first scanline, the second echo signal is given a weighted value of 1.0 and the third echo signal is given a weighted value of less than 1.0, and
for the second scanline, the second echo signal is given a weighted value of less than 1.0, and the third echo signal is given a weighted value of 1.0.
10. The system of claim 1 , wherein the processor is configured to receive:
the first echo signal at a first time;
the second echo signal at a second time; and
the third echo signal at a third time.