A high resolution intravascular ultrasound imaging system comprising: an image processor configured to be operably coupled with one or more electrical conduits of an imaging assembly contained in a catheter configured for percutaneous intravascular insertion, the image processor including: a pulser (301, 302, 304, 305, 306, 307) configured to energize an ultrasonic transducer of said imaging assembly with a signal, the ultrasonic transducer being located at or near a distal end of said catheter and configured to emit ultrasound energy towards a target blood vessel; and a receiver configured to receive and decompose ultrasound energy reflected by said target blood vessel and received by said imaging assembly into a plurality of individual subband signals, individually process said plurality of subband signals, and then reconstitute said plurality of subband signals into one or more imaging signals representing the target blood vessel; characterized in that: said signal with which the pulser is configured to energize the transducer is a multi-frequency waveform signal; and said plurality of individual subband signals includes a full bandwidth signal and at least one subband signal, and the at least one subband signal is a low frequency subband signal or a high frequency subband signal. an image processor configured to be operably coupled with one or more electrical conduits of an imaging assembly contained in a catheter configured for percutaneous intravascular insertion, the image processor including: a pulser (301, 302, 304, 305, 306, 307) configured to energize an ultrasonic transducer of said imaging assembly with a signal, the ultrasonic transducer being located at or near a distal end of said catheter and configured to emit ultrasound energy towards a target blood vessel; and a receiver configured to receive and decompose ultrasound energy reflected by said target blood vessel and received by said imaging assembly into a plurality of individual subband signals, individually process said plurality of subband signals, and then reconstitute said plurality of subband signals into one or more imaging signals representing the target blood vessel; a pulser (301, 302, 304, 305, 306, 307) configured to energize an ultrasonic transducer of said imaging assembly with a signal, the ultrasonic transducer being located at or near a distal end of said catheter and configured to emit ultrasound energy towards a target blood vessel; and a receiver configured to receive and decompose ultrasound energy reflected by said target blood vessel and received by said imaging assembly into a plurality of individual subband signals, individually process said plurality of subband signals, and then reconstitute said plurality of subband signals into one or more imaging signals representing the target blood vessel; characterized in that: said signal with which the pulser is configured to energize the transducer is a multi-frequency waveform signal; and said plurality of individual subband signals includes a full bandwidth signal and at least one subband signal, and the at least one subband signal is a low frequency subband signal or a high frequency subband signal. said signal with which the pulser is configured to energize the transducer is a multi-frequency waveform signal; and said plurality of individual subband signals includes a full bandwidth signal and at least one subband signal, and the at least one subband signal is a low frequency subband signal or a high frequency subband signal.