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

AlphaMissense Predictions and ClinVar Annotations: A Deep Learning Approach to Uveal Melanoma

Objective

Uveal melanoma (UM) poses significant diagnostic and prognostic challenges due to its variable genetic landscape. We explore the use of a novel deep learning tool to assess the functional impact of genetic mutations in UM.

Design

A cross-sectional bioinformatics exploratory data analysis of genetic mutations from UM cases.

Subjects

Genetic data from patients diagnosed with UM were analyzed, explicitly focusing on missense mutations sourced from the Catalogue of Somatic Mutations in Cancer (COSMIC) database.

Methods

We identified missense mutations frequently observed in UM using the COSMIC database, assessed their potential pathogenicity using AlphaMissense, and visualized mutations using AlphaFold. Clinical significance was cross-validated with entries in the ClinVar database.

Main Outcome Measures

The primary outcomes measured were the agreement rates between AlphaMissense predictions and ClinVar annotations regarding the pathogenicity of mutations in critical genes associated with UM, such as GNAQ, GNA11, SF3B1, EIF1AX, and BAP1.

Results

Missense substitutions comprised 91.35% (n = 1310) of mutations in UM found on COSMIC. Of the 151 unique missense mutations analyzed in the most frequently mutated genes, only 40.4% (n = 61) had corresponding data in ClinVar. Notably, AlphaMissense provided definitive classifications for 27.2% (n = 41) of the mutations, which were labeled as "unknown significance" in ClinVar, underscoring its potential to offer more clarity in ambiguous cases. When excluding these mutations of uncertain significance, AlphaMissense showed perfect agreement (100%) with ClinVar across all analyzed genes, demonstrating no discrepancies where a mutation predicted as "pathogenic" was classified as "benign" or vice versa.

Conclusions

Integrating deep learning through AlphaMissense offers a promising approach to understanding the mutational landscape of UM. Our methodology holds the potential to improve genomic diagnostics and inform the development of personalized treatment strategies for UM.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Measurement of Melanocytic Choroidal Lesions: Ultrasound Versus Ultrawide-Field Fundus Imaging System

OBJECTIVES

The aim of this study was to establish the concordance between conventional 20 Mhz ultrasonography and an ultrawide-field (UWF) imaging system (Optos® California) in the measurement of basal diameters of melanocytic choroidal tumors.

METHODS

A retrospective study comparing diagnostic tests was conducted in patients with untreated melanocytic choroidal lesions (either nevus or melanoma) who had undergone both UWF imaging and ultrasonography. Only cases with a clear visualization of tumor borders in both imaging modalities were included. Longitudinal and transversal base diameters of the melanocytic tumors were measured by 20 MHz US (one observer) and UWF fundus photography (two observers). Interobserver agreement was assessed for UWF imaging first to validate the technique. Then, UWF imaging measurements were compared with 20 MHz US results.

RESULTS

In total, 106 patient images were reviewed, of which 61 were excluded due to unclear visualization of tumor margins. We found excellent concordance (from ICC and defined Bland-Altman plots) for interobserver and inter-technique agreement in estimating basal diameters when using pseudocolor composite and red laser images by comparing them with 20 MHz US results.

CONCLUSIONS

UWF fundus imaging, when complete visualization of the tumor margins is possible, could be as reliable as ultrasonography in the measurement of the basal diameters of choroidal melanocytic tumors.

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

Ultrasound A-scan is an important tool for quantitative assessment of ocular lesions. However, its usability is limited by the difficulty of accurately localizing the ultrasound probe to a lesion of interest. In this study, a transparent LiNbO3 single crystal ultrasound transducer was fabricated, and integrated with a widefield fundus camera to guide the ultrasound local position. The electrical impedance, phase spectrum, pulse-echo performance, and optical transmission spectrum of the ultrasound transducer were validated. The novel fundus camera-guided ultrasound probe was tested for in vivo measurement of rat eyes. Anterior and posterior segments of the rat eye could be unambiguously differentiated with the fundus photography-guided ultrasound measurement. A model eye was also used to verify the imaging performance of the prototype device in the human eye. The prototype shows the potential of being used in the clinic to accurately measure the thickness and echogenicity of ocular lesions in vivo.

Ultrasound Flow Imaging Study on Rat Brain with Ultrasound and Light Stimulations

Functional ultrasound (fUS) flow imaging provides a non-invasive method for the in vivo study of cerebral blood flow and neural activity. This study used functional flow imaging to investigate rat brain's response to ultrasound and colored-light stimuli. Male Long-Evan rats were exposed to direct full-field strobe flashes light and ultrasound stimulation to their retinas, while brain activity was measured using high-frequency ultrasound imaging. Our study found that light stimuli, particularly blue light, elicited strong responses in the visual cortex and lateral geniculate nucleus (LGN), as evidenced by changes in cerebral blood volume (CBV). In contrast, ultrasound stimulation elicited responses undetectable with fUS flow imaging, although these were observable when directly measuring the brain's electrical signals. These findings suggest that fUS flow imaging can effectively differentiate neural responses to visual stimuli, with potential applications in understanding visual processing and developing new diagnostic tools.

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

This comprehensive review explores the role of sonographic assessment in diagnosing and characterizing peripheral slow-flow vascular malformations (PSFVM). The review begins with an introduction providing the background and significance of PSFVM, defining these vascular anomalies, and emphasizing the importance of sonography in their diagnosis. The objectives focus on a thorough examination of existing literature, assessing the effectiveness of sonography in delineating morphological and hemodynamic features crucial for accurate classification. The summary of key findings highlights the diagnostic accuracy of sonography while acknowledging its limitations. Implications for clinical practice emphasize the practical utility of sonography in early diagnosis and preoperative planning, suggesting integration into multimodal approaches. The conclusion underscores the need for standardized criteria, ongoing education, and future research, positioning sonography as a valuable tool in the comprehensive management of PSFVM.

Reliability of Panoramic Ultrasound in Assessing Rectus Femoris Size, Shape, and Brightness: An Inter-Examiner Study

Extended field-of-view ultrasound (US) imaging, also known as panoramic US, represents a technical advance that allows for complete visualization of large musculoskeletal structures, which are often limited in conventional 2D US images. Currently, there is no evidence examining whether the experience of examiners influences muscle shape deformations that may arise during the glide of the transducer in panoramic US acquisition. As no studies using panoramic US have analyzed whether two examiners with differing levels of experience might obtain varying scores in size, shape, or brightness during the US assessment of the rectus femoris muscle, our aim was to analyze the inter-examiner reliability of panoramic US imaging acquisition in determining muscle size, shape, and brightness between two examiners. Additionally, we sought to investigate whether the examiners' experience plays a significant role in muscle deformations during imaging acquisition by assessing score differences. Shape (circularity, aspect ratio, and roundness), size (cross-sectional area and perimeter), and brightness (mean echo intensity) were analyzed in 39 volunteers. Intraclass correlation coefficients (ICCs), standard error of measurements (SEM), minimal detectable changes (MDC), and coefficient of absolute errors (CAE%) were calculated. All parameters evaluated showed no significant differences between the two examiners (p > 0.05). Panoramic US proved to be reliable, regardless of examiner experience, as no deformations were observed. Further research is needed to corroborate the validity of panoramic US by comparing this method with gold standard techniques.

An Update on Multimodal Ophthalmological Imaging of Diffuse Choroidal Hemangioma in Sturge-Weber Syndrome

Sturge-Weber syndrome (SWS) is characterized by facial port-wine stains, leptomeningeal hemangiomas, and prominent ocular manifestations such as glaucoma and diffuse choroidal hemangiomas (DCHs). Imaging modalities are critical for diagnosing and longitudinally monitoring DCHs in SWS. Fundus photography is fundamental in assessing both eyes simultaneously, fluorescein angiography and indocyanine green angiography effectively map the retinal and choroidal circulation, and ultrasonography offers essential structural insights into the choroid and retina. NIR imaging reveals subtle retinal pigment changes, often overlooked in standard fundus examination. Enhanced depth imaging spectral domain optical coherence tomography (EDI-SDOCT) and swept-source OCT (SSOCT) improve the visualization of the choroidal-scleral boundary, essential for DCH characterization. The potential of OCT angiography (OCTA) is under exploration, particularly its role in predicting signs of disease progression or worsening, as well as potential new biomarkers such as the choroidal vascularity index (CVI). The present review aims to provide an update on multimodal imaging of DCHs in SWS.