Motion artifact reduction for IVUS-based thermal strain imaging

Abstract

Thermal strain imaging (TSI) using intravascular ultrasound (IVUS) has the potential to identify lipid pools within rupture-prone arterial plaques and serve as a valuable supplement to current IVUS systems in diagnosing acute coronary syndromes. The major challenge for in vivo application of TSI will be cardiac motion, including bulk motion and tissue deformation. Simulations based on an artery model, including a lipid-filled plaque, demonstrate that effective bulk motion compensation can be achieved within a certain motion range using spatial interpolation. We also propose a practical imaging scheme to minimize mechanical strains caused by tissue deformation based on a linear least squares fitting strategy. This scheme was tested on clinical data by artificially superimposing thermal displacements corresponding to different temperature rises. Results suggest a 1-2 C temperature rise is required to detect lipids in an atherosclerotic plaque in vivo.

Thermal strain imaging: a review

“…Also, an US heating/ imaging scheme using a single US probe connected to a commercial US scanner will provide significant system practicality, and it does not require a specially designed electromagnetically shielded room. In summary, both electromagnetic [20][21][22][23][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] and US heating [24][25][26][27][28][29][30][31] have been used to demonstrate the feasibility of TSI. Future clinical applications will primarily use US heating for TSI unless electromagnetic heating is already integrated into the system for therapeutic purposes.…”

“…Microwave radiation was used to induce a temperature rise, and thermal strains resulting from local changes in sound speed were estimated using phase-sensitive, correlation-based ST [51,53]. In later work from the same group [22,23], TSI was tested on a tissue phantom using intravascular ultrasound (IVUS) imaging catheters. The ultimate goal was to design an appropriate directed-energy source to provide controlled heating of coronary arteries during an IVUS procedure to help differentiate plaque characteristics in the coronaries using TSI.…”

“…Imaging of thermally dependent sound speed changes using a small temperature rise represents a potentially non-invasive tool to identify lipid pools and lipid-bearing tissue within otherwise waterbearing tissue. For this application, a directed-energy source is used to deliver a short heat pulse providing a localized, non-invasive temperature change of about only 1 -28C [20][21][22][23][24][25][27][28][29][30][31].…”

Ultrasound temperature estimation based on probability variation of backscatter data

“…For example, cardiac periodicity can be used to minimize motion artifacts by using electrocardiogram (ECG) signals to trigger ultrasound array firing. 56 For clinical systems not synchronized with ECG signals, motion compensation methods using spatial interpolation and linear least-squares fitting have been demonstrated to have the ability to minimize the effects of tissue motion for vessel studies 57 and during intracardiac imaging of the heart. 58 The above strategies may be combined with the proposed method (e.g., the ECG-gated ARCN pa image) for future clinical applications.…”

Medical ultrasound: imaging of soft tissue strain and elasticity

“…The method depends on the differential changes in the speed of sound resulting from exposure to microwave pulses producing small increases in temperature (typically 1 -28C), detected during intravascular scanning. A major problem with this approach is that of bulk motion and tissue deformation; for this, compensation techniques have begun to be developed [257].…”