OCT Technique – Optical Coherence Tomography

OCT Technique – Optical Coherence Tomography

What is Optical Coherence Tomography?

OCT – Optical Coherence Tomography is a light-based catheter which acquires on an image (photo) inside the heart blood vessel. OCT is a recently-developed, catheter-based Intravascular Imaging Technology that provides micron-scale resolution. It is a laser light equivalent of ultrasound imaging, measuring the intensity of backscattered infrared light rather than sound waves, and translates these optical echoes into a high-resolution, two-dimensional tomographic image. OCT has the highest imaging resolution of any currently-available technology. Cross-sectional resolutions of catheter-based OCT systems are in the range of 10-20 µm.

A case study of a patient who underwent both Fractional Flow Reserve (FFR) and OCT

A middle aged woman presented with Chest pain at Apollo Hospitals, India and underwent Coronary Angiogram which showed only a mild blockage in one of the blood vessels supplying the heart. As the patient was diabetic and had chest pain, we decided to investigate further with two tests, one based on physiology – Fractional Flow Reserve (FFR) FFR and the other based on imaging – Optical Coherence Tomography (OCT). OCT Image acquisition showed severely blocked artery which was spontaneously (by natural mechanisms) opened with small minute channels which were multiple. This was a surprise and a new finding not reported in the world.

The procedure can be explained as the dye given during angiogram passing through these multiple channels within the block, masks the severity of the block and show it as mild in the Angiogram. The pressure technique of Fractional Flow Reserve (FFR) and the light-based imaging technique (OCT) helped to unmask the mystery within the block.

Once the block was identified the patient underwent an Angioplasty and stenting successfully. OCT Imaging was repeated which showed good positioning of the stent within the vessel and the block were cleared.