Intravascular ultrasound system for co-registered imaging
An intravascular ultrasound imaging system comprises a catheter having an elongated body having a distal end and an imaging core arranged to be inserted into the elongated body. The imaging core is arranged to transmit ultrasonic energy pulses and to receive reflected ultrasonic energy pulses. The system further includes an imaging engine coupled to the imaging core and arranged to provide the imaging core with energy pulses to cause the imaging core to transmit the ultrasonic energy pulses. The energy pulses are arranged in repeated sequences and the energy pulses of each sequence have varying characteristics. The reflected pulses may be processed to provide a composite image of images resulting from each different characteristic.
1. An intravascular ultrasound imaging system comprising:
a catheter including a transducer configured to:
transmit first ultrasonic energy pulses in a repeating sequence that contain a first predefined ultrasonic energy pulse characteristic,
transmit second ultrasonic energy pulses in a repeating sequence that contain a second predefined ultrasonic energy pulse characteristic different than the first predefined ultrasonic energy pulse characteristic,
transmit third ultrasonic energy pulses in a repeating sequence that contain a third predefined ultrasonic energy pulse characteristic different than each of the first predefined ultrasonic energy pulse characteristic and the second predefined ultrasonic energy pulse characteristic, and
receive analog reflections of each of the first ultrasonic energy pulses, the second ultrasonic energy pulses, and the third ultrasonic energy pulses, and
an imaging engine coupled to the transducer to receive digitized reflections of each of the first ultrasonic energy pulses, the second ultrasonic energy pulses, and the third ultrasonic energy pulses, the digitized reflection of the first ultrasonic energy pulses including first image data, the digitized reflection of the second ultrasonic energy pulses including second image data, and the digitized reflection of the third ultrasonic energy pulses including third image data, the imaging engine configured to:
select a portion of the first image data representing a processed first image that is based on the selected portion of the first image data,
select a portion of the second image data representing a processed second image that is based on the selected portion of the second image data,
select a portion of the third image data representing a processed third image that is based on the selected portion of the third image data, and
combine the selected portion of the first image data, the selected portion of the second image data, and the selected portion of the third image data to create a composite image.
2. The system of claim 1 , wherein the imaging engine is further configured to co-register the first image data acquired from the first predefined ultrasonic energy pulse characteristic, the second image data acquired from the second predefined ultrasonic energy pulse characteristic, and the third image data acquired from the third predefined ultrasonic energy pulse characteristic.
3. The system of claim 1 , wherein the first predefined ultrasonic energy pulse characteristic comprises a first transmit energy level, wherein the second predefined ultrasonic energy pulse characteristic comprises a second transmit energy level that is less than the first transmit energy level, and wherein the third predefined ultrasonic energy pulse characteristic comprises a third transmit energy level that is less than the second transmit energy level,
wherein the transducer is configured to:
transmit the first ultrasonic energy pulses at the first energy level;
transmit the second ultrasonic energy pulses at the second energy level; and
transmit the third ultrasonic energy pulses at the third energy level.
4. The system of claim 3 , wherein the selected portion of the first image data comprises image data representing a first structure acquired at the first transmit energy level, wherein the first structure is located at a first distance away from the transducer, and wherein the selected portion of the second image data comprises image data representing a second structure acquired at the second transmit energy level, wherein the second structure is located at a second distance away from the transducer that is less than the first distance.
5. The system of claim 4 , wherein the imaging engine is further configured to adapt the second distance to be a distance that a stent is located from the transducer.
6. The system of claim 5 , wherein the imaging engine is further configured to adapt the second transmit energy level to prevent a stent blooming artifact.
7. The system of claim 5 , wherein the imaging engine is further configured to adapt the first distance to be a distance that a medial tissue layer is located from the transducer.
8. The system of claim 7 , wherein the imaging engine is further configured to adapt the first distance to be a distance that an adventitial tissue layer is located from the transducer.
9. The system of claim 4 , wherein image data representing the second structure comprises image data representing a stent, and wherein image data representing the first structure comprises image data representing a medial tissue layer and an adventitial tissue layer.
10. The system of claim 1 , wherein the composite image includes the selected portion of the first image data representing a medial tissue layer and the selected portion of the second image data representing neotissue growth over a stent, and wherein the composite image has characteristics such that no stent blooming artifact is included in the composite image.
11. The system of claim 10 , further comprising a display configured to visually present the composite image.
12. The system of claim 1 , wherein the transducer is further configured to receive the analog reflections of each of the first ultrasonic energy pulse, the second ultrasonic energy pulse, and the third ultrasonic energy pulses at substantially the same time.
13. A method comprising:
transmitting, by a transducer, first ultrasonic energy pulses in a repeating sequence that contain a first predefined ultrasonic energy pulse characteristic;
transmitting, by the transducer, second ultrasonic energy pulses in a repeating sequence that contain a second predefined ultrasonic energy pulse characteristic different than the first predefined ultrasonic energy pulse characteristic;
transmitting, by the transducer, third ultrasonic energy pulses in a repeating sequence that contain a third predefined ultrasonic energy pulse characteristic different than each of the first predefined ultrasonic energy pulse characteristic and the second predefined ultrasonic energy pulse characteristic;
receive analog reflections of each of the first ultrasonic energy pulses, the second ultrasonic energy pulses, and the third ultrasonic energy pulses;
receiving, by an imaging engine coupled to the transducer, digitized reflections of each of the first ultrasonic energy pulses, the second ultrasonic energy pulses, and the third ultrasonic energy pulses, the digitized reflection of the first ultrasonic energy pulses including first image data, the digitized reflection of the second ultrasonic energy pulses including second image data, and the digitized reflection of the third ultrasonic energy pulses including third image data;
selecting, by the imaging engine, a portion of the first image data representing a processed first image that is based on the selected portion of the first image data;
selecting, by the imaging engine, a portion of the second image data representing a processed second image that is based on the selected portion of the second image data;
selecting, by the imaging engine, a portion of the third image data representing a processed third image that is based on the selected portion of the third image data; and
combining the selected portion of the first image data the selected portion of the second image data, and the selected portion of the third image data to create a composite image.
14. The method of claim 13 , wherein the method further comprises receiving the analog reflections of each of the first ultrasonic energy pulses, the second ultrasonic energy pulses, and the third ultrasonic energy pulses at substantially the same time.
15. The method of claim 13 , wherein the first predefined ultrasonic energy pulse characteristic comprises a first transmit energy level, wherein the second predefined ultrasonic energy pulse characteristic comprises a second transmit energy level that is less than the first transmit energy level, and wherein the third predefined ultrasonic energy pulse characteristic comprises a third transmit energy level that is less than the second transmit energy level,
wherein the method further comprises:
transmitting, by the transducer, the first ultrasonic energy pulses at the first energy level;
transmitting, by the transducer, the second ultrasonic energy pulses at the second energy level; and
transmitting, by the transducer, the third ultrasonic energy pulses at the third energy level.
16. The method of claim 15 , wherein the selected portion of the first image data comprises image data representing a first structure acquired at the first transmit energy level, wherein the first structure is located at a first distance away from the transducer, and wherein the selected portion of the second image data comprises image data representing a second structure acquired at the second transmit energy level, wherein the second structure is located at a second distance away from the transducer that is less than the first distance.
17. The method of claim 16 , wherein the method further comprises:
adapting, by the imaging engine, the second distance to be a distance that a stent is located from the transducer; and
adapting, by the imaging engine, the first distance to be a distance that a medial tissue layer is located from the transducer.
18. The method of claim 13 , wherein the composite image includes the selected portion of the first image data representing a medial tissue layer and the selected portion of the second image data representing neotissue growth over a stent, and wherein the composite image has characteristics such that no stent blooming artifact is included in the composite image.