What is optical coherence tomography (OCT)?
Optical coherence tomography (OCT) is a diagnostic imaging study that uses low coherence light beams (1280-1300 nm) to analyze different parts of the human body and obtain particularly accurate and reliable multilevel tissue scans.
The methodology is currently used mainly in ophthalmology for the study of the cornea and retina, and in cardiology to monitor the condition of blood vessels where obstructions that could lead to more serious diseases are suspected.
What does it consist of?
OCT works in a similar way to ultrasound, with the difference that light waves are used instead of acoustic waves. In ophthalmology the procedure is not considered minimally invasive and uses infrared laser reflection to analyze the retina and cornea in its different tissue sections, obtaining precise and high resolution images of each layer. Thanks to the possibility of analyzing every part of the tissue (sagittal, frontal, three-dimensional) the test is able to detect multiple diseases, especially those involving the macular area and the optic papilla.
Imaging takes only a few minutes, during which the specialist uses special reference points on the optic papilla that receive and store the laser reflections.
The result is a kind of image biopsy of all the layers of the retina, with which multiple lesions can be detected. Once the images have been obtained, it will be possible to proceed with the analysis to identify the different pathologies.
In cardiology, the process is more invasive because the impulse must be sent through a catheter to the area to be analyzed. This means that the catheter must be placed in the vessel through an incision. Once the signal sent by the diode hits the clot, photon oscillations are produced and sent back to their source and intercepted by an interferometer, which will give an indication of the severity of the problem.
OCT is used in Ophthalmology to observe the cornea and retina, but also in Cardiology to observe the blood vessels.
Why is it performed?
OCT is used in ophthalmology to diagnose and evaluate the development of retinal pathologies such as maculopathies and glaucoma, hereditary retinal dystrophies, diseases of the vitreoretinal area, central serous chorioretinopathy and macular edema of various origins.
This test is also often used as the preferred method before using the much more invasive fluorangiography.
In cardiology the scan is useful in assessing the presence of thrombus, plaques, calcium deposits or the incorrect position of a stent in blood vessels, especially in the prevention of arteriosclerosis.
Optical coherence tomography (OCT) preparation
When performed in ophthalmology, the scan does not require any preparation, not even the use of eye drops, as the machine never directly touches the patient’s eye. The use of contact lenses during the procedure is obviously not allowed. In cardiology, on the other hand, local anesthesia will be required to insert the catheter and guide it to the affected area, as well as the use of anticoagulants to avoid possible complications during or after surgery.
What does the test feel like?
Neither test is painful. For the eye examination, the patient must simply remain seated and stare at the light sent by the machine, while for the cardiac examination the patient is lying down under local anesthesia.