Ultrasound in ocular oncology: Technical advances, clinical applications, and limitations

Abstract

Due to its accessibility and ability for real-time image acquisition of ocular structures, ultrasound has high utility in the visualization of the eye, especially in ocular oncology. In this minireview, we summarize the technical rationale and applications of ultrasound modalities, A-scan, B-scan, high-frequency ultrasound biomicroscopy (UBM), and Doppler measurement. A-scan ultrasound uses a transducer of 7–11 MHz, making it useful for determining the echogenicity of ocular tumors (7–8 MHz) and measuring the axial length of the eye (10–11 MHz). B-scan ultrasound operates at 10–20 MHz, which can be used for measuring posterior ocular tumors while UBM operates at 40–100 MHz to evaluate anterior ocular structures. Doppler ultrasonography allows for the detection of tumor vascularization. While ultrasonography has numerous clinical applications due to its favorable penetration compared with optical coherence tomography, it is still limited by its relatively lower resolution. Ultrasound also requires an experienced sonographer due to the need for accurate probe localization to areas of interest.

Integrating a Fundus Camera with High-Frequency Ultrasound for Precise Ocular Lesion Assessment

“…Therefore, we were not able to conduct ultrasound measurements from the human eye with this preliminary light-ultrasound prototype. Ultrasound probes used in ophthalmology clinics generally have a center frequency between 7 MHz and 20 MHz [ 16 ] to compensate for the attenuation to enhance the penetration depth. We are currently pursuing a transparent ultrasound transducer with a frequency similar to the clinical ophthalmic ultrasound systems for future studies of human eyes.…”

“…Ultrasound imaging of the eye has been a longstanding imaging technique due to its excellent tissue penetration capability, non-invasive nature, and ability to differentiate tissues with different echogenicity [ 15 , 16 ]. Experimental research with different ultrasound transducer materials and frequencies is also gaining popularity for non-invasive imaging of the eye [ 17 , 18 , 19 ].…”

“…A specifically designed A-scan probe called standardized A-scan with non-focused parallel beam and S-shaped amplification was optimized for eye bio-microscopy [ 22 , 23 ] and has been an important part of many ophthalmology clinics ever since. Standardized A-scan has become the gold standard for calculating the apical height of ocular lesions, specifically because of its enhanced penetration capability and ability to differentiate the lesion border from the scleral tissue [ 15 , 16 , 21 ]. Several quantifiable parameters other than the apical height have been extracted out of A-scan ultrasounds, such as median internal reflectivity (%) of a lesion, heterogenous/homogenous echogenicity, number of internal reflectivity peaks inside a lesion, and sound attenuation pattern (angle ĸ) to facilitate an accurate clinical diagnosis [ 12 , 15 , 24 ].…”

A Comprehensive Review of Sonographic Assessment of Peripheral Slow-Flow Vascular Malformations

“…Integrating dermoscopy and high-frequency ultrasound (HFUS) has proven promising in predicting and monitoring therapeutic response in this context [ 24 ]. In ocular oncology, ultrasound is crucial in assessing the treatment response of lesions such as uveal melanoma and retinoblastoma [ 25 ]. Through the measurement of thickness and the differentiation between flat and elevated lesions, ultrasound provides valuable insights for monitoring tumor growth and detecting local recurrence in treated uveal melanoma [ 25 ].…”

“…In ocular oncology, ultrasound is crucial in assessing the treatment response of lesions such as uveal melanoma and retinoblastoma [ 25 ]. Through the measurement of thickness and the differentiation between flat and elevated lesions, ultrasound provides valuable insights for monitoring tumor growth and detecting local recurrence in treated uveal melanoma [ 25 ]. The clinical utility of sonography extends to the domain of vascular anomalies, where it is employed for both preoperative evaluation and monitoring treatment response [ 23 ].…”