Near infrared spectroscopic imaging along with intravascular ultrasound

Near infrared spectroscopic imaging along with intravascular ultrasound

A new combination catheter system with ability for intravascular ultra sound imaging (IVUS) along with near infrared spectroscopic imaging (NIRS) has been developed as the TVC Imaging System TM (MC 7 system, InfraReDx, Burlington, Massachusetts). NIRS is able to detect lipid rich core of the plaques and assigns red colour to low probability and yellow colour to high probability. IBIS-3 (Integrated Biomarker and Imaging Study 3) [Simsek C et al. The ability of high dose rosuvastatin to improve plaque composition in non-intervened coronary arteries: rationale and design of the Integrated Biomarker and Imaging Study-3 (IBIS-3). EuroIntervention. 2012 Jun 20;8(2):235-41] is evaluating the effect of rosuvastatin on lipid rich coronary plaques is utilizing this combo catheter.

NIRS imaging is done with a motorised catheter pull back at a speed of 0.5 millimeter per second. The amount of lipid core plaque is displayed as a chemogram with pull back position in millimeters on x-axis and the circumferential position of the measurement in degrees on on the y-axis as if the coronary vessel is split open on the longitudinal axis. Red pixels indicates no lipid and yellow pixels indicates more than 60% while black indicates lack of enough data. NIRS derived lipid core burden index (LCBI) score is calculated by multiplying the fraction of valid yellow pixels by 1000.
IVUS imaging is frequently being used to aid percutaneous coronary intervention (PCI), especially to optimize the results as it can assess the stent apposition very well. This is useful in critical regions like the unprotected left main where incomplete stent apposition leading to stent thrombosis could be catastrophic. Adding NIRS imaging to the same catheter would help in identifying vulnerable lipid rich plaques which may need to be addressed even if they are not producing critical luminal narrowing.