Imaging Techniques in the Diagnosis and Management of Ocular Tumors: Prospects and Challenges

Cysts and tumours of the iris: Diagnostic tools and key management considerations-A review

The iris is a unique structure, with exquisite variations in colour and form. Pathological changes, specifically including iris cysts and tumours are relatively uncommon, difficult to diagnose, and yet potentially blinding or life-threatening. Based on a comprehensive literature review, with highly illustrated key case examples, this report aims to guide the clinician in filtering the differential diagnoses of iris cysts and tumours. Evaluation is in the context of key diagnostic clinical tools and management considerations. Diagnostic imaging techniques include serial anterior segment photography, ultrasound, anterior segment optical coherence tomography, and iris fluorescein angiography, however, the roles of computerised topography and magnetic resonance imaging are also considered in this review. Management includes categorisation in terms of solid iris tumours (melanocytic vs. non-melanocytic), or iris cysts (primary vs. secondary) that may be usefully differentiated by clinical assessment, avoiding more invasive interventions. Cystic lesions are generally benign, although implantation cysts in particular cause significant complications and surgical challenges. Most solid tumours are melanocytic and also typically benign. However, in larger lesions, rapid growth, symptoms and complications more likely indicate malignancy, requiring further investigation.

A Systematic Review and Meta-Analysis on the Diagnostic and Prognostic Values of 18F-FDG PET in Uveal Melanoma and Its Hepatic Metastasis

In this systematic review and meta-analysis (PRISMA-compliant), we tried to investigate diagnostic and prognostic values of 18F-FDG PET in uveal melanoma. A systematic search was conducted on the main medical literature databases to include studies that evaluated 18F-FDG PET as the imaging modality to evaluate patients with uveal melanoma. Overall, 27 studies were included. Twelve had data about the detection rate of 18F-FDG PET in primary intra-ocular tumours. The pooled sensitivity was 45% (95%CI: 41-50%). Furthermore, studies showed that the larger the primary tumour, the higher its uptake. Among the included studies, 13 assessed 18F-FDG PET in detecting metastasis. The pooled sensitivity and specificity were 96% (95%CI: 81-99%) and 100% (95%CI: 94-100%), respectively. Regarding liver metastasis, they were 95% (95%CI: 79-99%) and 100% (95%CI: 91-100%), respectively. Noteworthy, the level of 18F-FDG uptake was a strong predictor of patient survival. Lastly, 18F-FDG PET could characterise lesions from the histopathology perspective, distinguishing high-risk from low-risk diseases. Overall, although not reliable in detecting primary intra-ocular tumours, 18F-FDG PET is highly accurate for diagnosing metastatic uveal melanomas. It can also be a highly valuable modality in terms of patient prognostication. Thus, 18F-FDG PET can be recommended in patients diagnosed with uveal melanoma to enhance decision-making and patient management.

Recent progress in retinoblastoma: Pathogenesis, presentation, diagnosis and management

Retinoblastoma, the primary ocular malignancy in pediatric patients, poses a substantial threat to mortality without prompt and effective management. The prognosis for survival and preservation of visual acuity hinges upon the disease severity at the time of initial diagnosis. Notably, retinoblastoma has played a crucial role in unraveling the genetic foundations of oncogenesis. The process of tumorigenesis commonly begins with the occurrence of biallelic mutation in the RB1 tumor suppressor gene, which is then followed by a cascade of genetic and epigenetic alterations that correspond to the clinical stage and pathological features of the tumor. The RB1 gene, recognized as a tumor suppressor, encodes the retinoblastoma protein, which plays a vital role in governing cellular replication through interactions with E2F transcription factors and chromatin remodeling proteins. The diagnosis and treatment of retinoblastoma necessitate consideration of numerous factors, including disease staging, germline mutation status, family psychosocial factors, and the resources available within the institution. This review has systematically compiled and categorized the latest developments in the diagnosis and treatment of retinoblastoma which enhanced the quality of care for this pediatric malignancy.

Comparative analysis of ultrasonic elastosonography and contrast-enhanced ultrasonography in the diagnosis of benign and malignant intraocular tumors

PURPOSE

To compare the diagnostic value of ultrasonic elastosonography (UE) and contrast-enhanced ultrasonography (CEUS) for benign and malignant intraocular tumors.

METHODS

This retrospective study enrolled patients with intraocular tumors at Beijing Tongren Hospital, Capital Medical University (August 2016 to January 2020). The strain rate ratio (strain rate of tumor tissue divided by strain rate of surrounding normal tissue) was measured by UE. CEUS was performed using SonoVue® contrast agent. The performance of each method at differentiating benign from malignant intraocular tumors was evaluated by receiver operating characteristic curve analysis.

RESULTS

The analysis included 147 eyes in 145 patients (45.6 ± 13.4 years-old; 66 males): 117 patients (119 eyes) with malignant tumors and 28 patients (28 eyes) with benign tumors. At an optimal cutoff of 22.67 for the strain rate ratio, UE distinguished benign from malignant tumors with a sensitivity of 86.6% and a specificity of 96.4%. CEUS showed that 117 eyes with malignant tumors had a fast-in, fast-out time-intensity curve, and only two eyes with malignant tumors had a fast-in, slow-out curve, while all 28 eyes with benign tumors had a fast-in, slow-out curve. CEUS differentiated benign from malignant tumors with a sensitivity of 98.3% and a specificity of 100%. The diagnostic results differed significantly between the two methods (P = 0.004, McNemar test). The diagnostic performances of the two tests were moderately consistent (κ = 0.657, P < 0.001).

CONCLUSION

Both CEUS and UE have good diagnostic value in the differentiation of benign intraocular tumors from malignant intraocular tumors.

State of the Art of Pharmacological Activators of p53 in Ocular Malignancies

The pivotal role of p53 in the regulation of a vast array of cellular functions has been the subject of extensive research. The biological activity of p53 is not strictly limited to cell cycle arrest but also includes the regulation of homeostasis, DNA repair, apoptosis, and senescence. Thus, mutations in the p53 gene with loss of function represent one of the major mechanisms for cancer development. As expected, due to its key role, p53 is expressed throughout the human body including the eye. Specifically, altered p53 signaling pathways have been implicated in the development of conjunctival and corneal tumors, retinoblastoma, uveal melanoma, and intraocular melanoma. As non-selective cancer chemotherapies as well as ionizing radiation can be associated with either poor efficacy or dose-limiting toxicities in the eye, reconstitution of the p53 signaling pathway currently represents an attractive target for cancer therapy. The present review discusses the role of p53 in the pathogenesis of these ocular tumors and outlines the various pharmacological activators of p53 that are currently under investigation for the treatment of ocular malignancies.

CDNet: Contrastive Disentangled Network for Fine-Grained Image Categorization of Ocular B-Scan Ultrasound

Precise and rapid categorization of images in the B-scan ultrasound modality is vital for diagnosing ocular diseases. Nevertheless, distinguishing various diseases in ultrasound still challenges experienced ophthalmologists. Thus a novel contrastive disentangled network (CDNet) is developed in this work, aiming to tackle the fine-grained image categorization (FGIC) challenges of ocular abnormalities in ultrasound images, including intraocular tumor (IOT), retinal detachment (RD), posterior scleral staphyloma (PSS), and vitreous hemorrhage (VH). Three essential components of CDNet are the weakly-supervised lesion localization module (WSLL), contrastive multi-zoom (CMZ) strategy, and hyperspherical contrastive disentangled loss (HCD-Loss), respectively. These components facilitate feature disentanglement for fine-grained recognition in both the input and output aspects. The proposed CDNet is validated on our ZJU Ocular Ultrasound Dataset (ZJUOUSD), consisting of 5213 samples. Furthermore, the generalization ability of CDNet is validated on two public and widely-used chest X-ray FGIC benchmarks. Quantitative and qualitative results demonstrate the efficacy of our proposed CDNet, which achieves state-of-the-art performance in the FGIC task.

Magnetic Resonance Imaging in the Clinical Care for Uveal Melanoma Patients-A Systematic Review from an Ophthalmic Perspective

Conversely to most tumour types, magnetic resonance imaging (MRI) was rarely used for eye tumours. As recent technical advances have increased ocular MRI's diagnostic value, various clinical applications have been proposed. This systematic review provides an overview of the current status of MRI in the clinical care of uveal melanoma (UM) patients, the most common eye tumour in adults. In total, 158 articles were included. Two- and three-dimensional anatomical scans and functional scans, which assess the tumour micro-biology, can be obtained in routine clinical setting. The radiological characteristics of the most common intra-ocular masses have been described extensively, enabling MRI to contribute to diagnoses. Additionally, MRI's ability to non-invasively probe the tissue's biological properties enables early detection of therapy response and potentially differentiates between high- and low-risk UM. MRI-based tumour dimensions are generally in agreement with conventional ultrasound (median absolute difference 0.5 mm), but MRI is considered more accurate in a subgroup of anteriorly located tumours. Although multiple studies propose that MRI's 3D tumour visualisation can improve therapy planning, an evaluation of its clinical benefit is lacking. In conclusion, MRI is a complementary imaging modality for UM of which the clinical benefit has been shown by multiple studies.

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

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.

Imaging of Uveal Melanoma—Current Standard and Methods in Development

Simple Summary

Uveal melanoma is the most prevalent intraocular tumor in adults, derived from melanocytes; the liver is the most common site of its metastases. Due to troublesome tumor localization, different imaging techniques are utilized in diagnostics, i.e., fundus imaging (FI), ultrasonography (US), optical coherence tomography (OCT), single-photon emission computed tomography (SPECT), positron emission tomography/computed tomography (PET/CT), magnetic resonance imaging (MRI), fundus fluorescein angiography (FFA), indocyanine green angiography (ICGA), or fundus autofluorescence (FAF). Specialists eagerly use these techniques, but sometimes the precision and quality of the obtained images are imperfect, raising diagnostic doubts and prompting the search for new ones. In addition to analyzing the currently utilized methods, this review also introduces experimental techniques that may be adapted to clinical practice in the future. Moreover, we raise the topic and present a perspective for personalized medicine in uveal melanoma treatment.

Abstract

Uveal melanoma is the most common primary intraocular malignancy in adults, characterized by an insidious onset and poor prognosis strongly associated with tumor size and the presence of distant metastases, most commonly in the liver. Contrary to most tumor identification, a biopsy followed by a pathological exam is used only in certain cases. Therefore, an early and noninvasive diagnosis is essential to enhance patients’ chances for early treatment. We reviewed imaging modalities currently used in the diagnostics of uveal melanoma, including fundus imaging, ultrasonography (US), optical coherence tomography (OCT), single-photon emission computed tomography (SPECT), fundus fluorescein angiography (FFA), indocyanine green angiography (ICGA), fundus autofluorescence (FAF), as well as positron emission tomography/computed tomography (PET/CT) or magnetic resonance imaging (MRI). The principle of imaging techniques is briefly explained, along with their role in the diagnostic process and a summary of their advantages and limitations. Further, the experimental data and the advancements in imaging modalities are explained. We describe UM imaging innovations, show their current usage and development, and explain the possibilities of utilizing such modalities to diagnose uveal melanoma in the future.

The Xiangya Ocular Tumor Bank: A Disease-Specific Biobank for Advancing Translational Research Into Ocular Tumors

The pathogenesis and etiology of various ocular tumors remain largely unclear, limiting the development of diagnostic and treatment approaches for such tumors. Tissue samples from patients are also valuable resource to elucidate mechanisms underlying tumorigenesis. Here we present the early phase setup of an ocular tumor biobank at Xiangya Hospital. Blood and tissue samples along with associated clinical data were obtained from patients who underwent surgery in the Department of Ophthalmology of Xiangya Hospital from December 1, 2018 to January 31, 2020. Standardized operating protocols were developed for the collection, transportation, processing and preservation of ocular tumor samples. A total of 92 clinical cases suffered from 21 types of eye tumors and several undiagnosed eye diseases were covered. A total of 846 samples were preserved in the ocular tumor biobank, including 356 blood samples (42.1%), 324 plasma samples (38.3%), and 166 tissue samples (19.6%). Using the clinical data, we analyzed the prevalence of malignant ocular tumors in association with variables of age, gender, tumors' location and size, and presenting complaints of lump and proptosis. The factors predictive of malignant ocular tumors, included gender (B = 1.599; P = 0.025) and the symptom of proptosis (B = −2.534; P = 0.001). Overall, the setup of clinically-based ophthalmologic biobank could support pathological and translational research into ocular tumors.

Diagnostic methods and therapeutic options of uveal melanoma with emphasis on MR imaging-Part I: MR imaging with pathologic correlation and technical considerations

Uveal melanoma is a malignant neoplasm that derives from pigmented melanocytes of the uvea and involves, in order of decreasing prevalence, the choroid, ciliary body and iris. Its prognosis is related to histopathologic and genetic features, tumor size and location, extraocular extension. The diagnosis is fundamentally based on clinical evaluation (ophthalmoscopy, biomicroscopy) and ultrasonography. MRI is useful in case of untransparent lens or subretinal effusion. Moreover, MRI has a significant role to confirm the diagnosis, in the evaluation of the local extent of the disease with implications for treatment planning, and in the follow-up after radiotherapy treatment. Uveal melanoma can show different morphologic features (lentiform, dome or mushroom shape) and often determines retinal detachment. MR appearance of uveal melanoma mainly depends on the melanin content. Uveal melanoma typically displays high signal intensity on T1-weighted images and low signal intensity on T2-weighted images. Nevertheless, imaging appearance may be variable based on the degree of pigmentation and the presence of areas of necrosis or cavitation. Differential diagnosis includes other uveal lesions. The radiologists and in particular MRI play a significant role in the clinical management of uveal melanoma. The purpose of this pictorial review is to provide the radiologists with awareness about diagnostic methods and therapeutic options of uveal melanoma. In the present first section we summarize the MR anatomy of the eye and describe ophthalmological and radiological imaging techniques to diagnose uveal melanomas, with emphasis on the role of MR imaging. Additionally, we review MR imaging appearance of uveal melanomas.

Multi-Functionalized Nanomaterials and Nanoparticles for Diagnosis and Treatment of Retinoblastoma

Retinoblastoma is a rare type of cancer, and its treatment, as well as diagnosis, is challenging, owing to mutations in the tumor-suppressor genes and lack of targeted, efficient, cost-effective therapy, exhibiting a significant need for novel approaches to address these concerns. For this purpose, nanotechnology has revolutionized the field of medicine with versatile potential capabilities for both the diagnosis, as well as the treatment, of retinoblastoma via the targeted and controlled delivery of anticancer drugs via binding to the overexpressed retinoblastoma gene. Nanotechnology has also generated massive advancements in the treatment of retinoblastoma based on the use of surface-tailored multi-functionalized nanocarriers; overexpressed receptor-based nanocarriers ligands (folate, galactose, and hyaluronic acid); lipid-based nanocarriers; and metallic nanocarriers. These nanocarriers seem to benchmark in mitigating a plethora of malignant retinoblastoma via targeted delivery at a specified site, resulting in programmed apoptosis in cancer cells. The effectiveness of these nanoplatforms in diagnosing and treating intraocular cancers such as retinoblastoma has not been properly discussed, despite the increasing significance of nanomedicine in cancer management. This article reviewed the recent milestones and future development areas in the field of intraocular drug delivery and diagnostic platforms focused on nanotechnology.

An Overview of Retinoblastoma and Enucleation in Pediatric Patients

Retinoblastoma is a rare malignancy of the eye affecting children, most commonly four years old and younger. Although chemotherapy and radiation treatment aim to spare the eye, in some cases, enucleation (ie, removal of the eye) is required to prevent cancer metastases or recurrence. Enucleation procedures are primarily performed at specialty institutions and may involve the surgical placement of an implant in the orbit of the eye. Unique perioperative considerations are required because of the age of the child at the time of the diagnosis and procedure and the involvement of a parent or caregiver who will be caring for the child postoperatively. This article presents an overview of retinoblastoma and enucleation and discusses the care and management of the unique patient population undergoing enucleation.

The Effectiveness of Ultrasound Biomicroscopic and Anterior Segment Optical Coherence Tomography in the Assessment of Anterior Segment Tumors: Long-Term Follow-Up

Background

Differential diagnosis and follow-up of small anterior segment tumors constitute a particular challenge because they determine further treatment procedures. The aim of this study was to evaluate the efficacy of the UBM (ultrasound biomicroscopy) and AS-OCT (anterior segment optical coherent tomography) in distinguishing different types of anterior segment lesions.

Methods

It was a retrospective, noncomparative study of case series of 89 patients with the suspicion of anterior segment tumor referred to the Ophthalmology Clinic, Medical University of Białystok, Poland, between 2016 and 2020. UBM was used to assess tumor morphology including height, location, and internal and external features. In cases in which UBM did not provide enough data, the AS-OCT images were analyzed. The data on demographics, best corrected visual acuity (BCVA), intraocular pressure (IOP), and rate of complications were also collected. Patients were followed up from 1 to 48 months.

Results

The mean observation period was 26.61 ± 16.13 months. Among the patients, there were 62 women and 27 men at a mean age of 55.59 ± 19.48 (range: from 20 to 89 years.) The types of tumors were cysts (41%), solid iris tumors (37.1%), ciliary body tumors (7.9%), peripheral anterior synechiae (PAS 3.4%), corneal tumors (4.5%), and others (5.6%). Patients with cysts were younger than patients with solid iris tumor (p=0.002). Women had a cyst as well as solid iris tumor more frequently than men, but less often a ciliary body tumor (p < 0.05). The horizontal size of tumor was positively correlated with patients' age (r_s = 0.38 and p=0.003) and negatively correlated with visual acuity (r_s = −0.42 and p=0.014). During the 4 years of diagnosis, only 2.2% of lesions exhibited growth (growth rate of 0.02 mm per year). Among 15 cases in which visualization with UBM was not satisfactory (mostly iris nevi), AS-OCT was helpful in diagnosis of 13 patients.

Conclusions

Both UBM and AS-OCT are effective methods in detection and diagnosis of tumors of the anterior eye segment, but in some cases, AS-OCT adds additional value to the diagnosis. Many lesions can be managed conservatively because they did not demonstrate growth during 4 years of the follow-up period.

Insights into Hypoxia: Non-invasive Assessment through Imaging Modalities and Its Application in Breast Cancer

Oxygen is crucial to maintain the homeostasis in aerobic cells. Hypoxia is a condition in which cells are deprived of the oxygen supply necessary for their optimum performance. Whereas oxygen deprivation may occur in normal physiological processes, hypoxia is frequently associated with pathological conditions. It has been identified as a stressor in the tumor microenvironment, acting as a key mediator of cancer development. Numerous pathways are activated in hypoxic cells that affect cell signaling and gene regulation to promote the survival of these cells by stimulating angiogenesis, switching cellular metabolism, slowing their growth rate, and preventing apoptosis. The induction of dysregulated metabolism in cancer cells by hypoxia results in aggressive tumor phenotypes that are characterized by rapid progression, treatment resistance, and poor prognosis. A non-invasive assessment of hypoxia-induced metabolic and architectural changes in tumors is advisable to fully improve breast cancer (BC) patient management, by potentially reducing the need for invasive biopsy procedures and evaluating tumor response to treatment. This review provides a comprehensive overview of the molecular changes in breast tumors secondary to hypoxia and the non-invasive imaging alternatives to evaluate oxygen deprivation, with an emphasis on their application in BC and the advantages and limitations of the currently available techniques.