Technology gives rise to diagnostic breakthroughs (Part – I)

Several technologies are being combined in novel ways to address previously intractable problems
By: GREG FREIHERR
Engineering advances over the last decade have resulted in clinical technology that may permit physicians to use their ultrasound scanners in ways they have previously only dreamed about.
Myocardial perfusion imaging with ultrasound can sometimes replace traditional techniques, with harmonic and sub-harmonic imaging generating better images of the coronaries and other parts of the body. While 3-D has yet to reach its potential in real-time image presentation, many mainstream systems generate volumetric images in less than a minute, opening the door to new diagnostic opportunities.
In achieving these capabilities, no single technological advance stands alone; several techniques are combined in novel ways to address previously intractable problems.
No better example arises than the evolution of micro-bubble contrast agents. Several years ago, these agents were designated as the best approach for visualizing myocardial perfusion . Micro-bubbles improve image quality, partly because their shells and the gas inside strongly reflect ultrasound waves. This reflectivity vastly increased signal strength, but clinical tests found the agents lacking-until ultrasound technology was adapted especially for use with micro-bubbles. This innovation changed the picture in myocardial perfusion .
Harmonic imaging and micro-bubble contrast agents, possibly in combination with pulse inversion and power Doppler, have produced clinical results comparable to those of nuclear medicine. At Northwick Park Hospital in Harrow, U.K., researchers studied power Doppler harmonic imaging in the assessment of myocardial perfusion. They compared ultrasound using micro-bubble contrast with single-photon emission computed tomography with technetium-99m sestamibi in 15 patients.