[Optical coherence tomography--high-resolution tissue imaging, but not histology!]

Area of Science:

• Ophthalmology
• Medical Imaging
• Histopathology

Context:

• Optical coherence tomography (OCT) is a key non-invasive retinal imaging technique, with spectral domain OCT (SD-OCT) offering high resolution.
• Correlation between OCT and histology is well-established for physiological retinas across species.
• Histological validation of pathological human retinal OCT images is scarce due to limited sample availability.

Purpose:

• To highlight the challenges and potential pitfalls in interpreting OCT images of pathologically altered human retinas.
• To emphasize the discrepancies between OCT reflectivity and histological findings at a cellular level.
• To encourage critical and attentive interpretation of OCT scans in clinical and research settings.

Summary:

• While OCT excels at visualizing gross retinal structures, its reflectivity signals do not always correlate with underlying cellular changes or histological features.
• Studies on animal models reveal OCT artifacts and demonstrate that conditions like retinal scars may appear deceptively similar to healthy tissue in OCT scans.
• Differences in lesion size measurements between OCT and histology (e.g., photocoagulation) underscore that OCT reflectivity indicates distinct tissue states compared to traditional histological staining.

Impact:

• Addresses a critical gap in understanding OCT limitations for pathological conditions, particularly in human retinas.
• Aims to reduce misinterpretations of OCT images by raising awareness of the disconnect between OCT appearance and cellular-level histology.
• Promotes more accurate diagnostic and research applications of OCT by fostering a critical approach to image interpretation.