Retinoblastoma: MR imaging parameters in detection of tumor extent

Diagnostic Imaging for Retinoblastoma Cancer Staging: Guide for Providing Essential Insights for Ophthalmologists and Oncologists

Retinoblastoma is the most common cause of all intraocular pediatric malignancies. It is caused by the loss of RB1 tumor suppressor gene function, although some tumors occur due to MYCN oncogene amplification with normal RB1 genes. Nearly half of all retinoblastomas occur due to a hereditary germline RB1 pathogenic variant, most of which manifest with bilateral tumors. This germline RB1 mutation also predisposes to intracranial midline embryonal tumors. Accurate staging of retinoblastoma is crucial in providing optimal vision-, eye-, and life-saving treatment. The AJCC Cancer Staging Manual has undergone significant changes, resulting in a universally accepted system with a multidisciplinary approach for managing retinoblastoma. The authors discuss the role of MRI and other diagnostic imaging techniques in the pretreatment assessment and staging of retinoblastoma. A thorough overview of the prevailing imaging standards and evidence-based perspectives on the benefits and drawbacks of these techniques is provided. Published under a CC BY 4.0 license. Test Your Knowledge questions for this article are available in the supplemental material.

Understanding Visual Disorders through Correlation of Clinical and Radiologic Findings

Patients presenting with visual disturbances often require a neuroimaging approach. The spectrum of visual disturbances includes three main categories: vision impairment, ocular motility dysfunction, and abnormal pupillary response. Decreased vision is usually due to an eye abnormality. However, it can also be related to other disorders affecting the visual pathway, from the retina to the occipital lobe. Ocular motility dysfunction may follow disorders of the cranial nerves responsible for eye movements (ie, oculomotor, trochlear, and abducens nerves); may be due to any abnormality that directly affects the extraocular muscles, such as tumor or inflammation; or may result from any orbital disease that can alter the anatomy or function of these muscles, leading to diplopia and strabismus. Given that pupillary response depends on the normal function of the sympathetic and parasympathetic pathways, an abnormality affecting these neuronal systems manifests, respectively, as pupillary miosis or mydriasis, with other related symptoms. In some cases, neuroimaging studies must complement the clinical ophthalmologic examination to better assess the anatomic and pathologic conditions that could explain the symptoms. US has a major role in the assessment of diseases of the eye and anterior orbit. CT is usually the first-line imaging modality because of its attainability, especially in trauma settings. MRI offers further information for inflammatory and tumoral cases. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

MRI features for prediction of the intravenous chemotherapy effect in patients with retinoblastoma

AIM

To investigate the value of orbital magnetic resonance imaging (MRI) features in predicting the efficacy of intravenous chemotherapy (IVC) for patients with retinoblastoma (RB).

MATERIALS AND METHODS

The pretreatment clinical and MRI data of 100 eyes from 80 RB patients who underwent IVC were collected retrospectively. There were 59 eyes in the effective group and 41 eyes in the ineffective group, and the baseline data of the two groups were compared statistically. Three radiologists reviewed and evaluated each lesion independently based on 25 MRI features. The predictive values of the MRI features for IVC efficacy were assessed by multi-factor logistic regression analysis, and their odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated. Receiver operating characteristic curves (ROCs) with the area under the curve (AUC) were used to determine the predictive abilities. A predictive model was constructed by integrating all independent predictors visualised by the nomogram.

RESULTS

There were no statistically significant differences in sex or age between the effective and ineffective groups. The results of multivariate regression analysis showed that laterality, margin, and anterior eye segment enhancement were identified as independent factors that could predict IVC efficacy. The predictive model combining these three features was constructed, and it had an AUC of 0.732 (95% CI: 0.633, 0.831, p<0.01), a sensitivity of 71.2%, and a specificity of 70.7%.

CONCLUSION

The data demonstrate that the orbital MRI features can be used to predict IVC efficiency before RB patients are treated.

Can Enhancement Pattern in Normal-Sized Optic Nerves on Magnetic Resonance Imaging Better Predict Tumor Invasion in Retinoblastoma Eyes?

Introduction

Optic nerve (ON) enhancement alone without ON thickening on contrast-enhanced magnetic resonance imaging (CE-MRI) can be associated with post-laminar optic nerve invasion (PLONI) in eyes with group E retinoblastoma. A few case reports and retrospective studies in the literature show a poor correlation between ON enhancement on MRI and ON invasion on histopathological examination (HPE). There is no universal consensus on the management of such cases. It is desirable that the presence and extent of a true ON invasion be reliably picked up before planning upfront enucleation in order to avoid stage II disease.

Methods

In a prospective study conducted at a tertiary eye care center in North India, all retinoblastoma patients presenting with ON enhancement on imaging were evaluated. Demographic and imaging details, histopathological findings, and treatment details were recorded. The length and pattern of enhancement noted on MRI were correlated with histopathology. Follow-up was done till the end of the study period.

Results

Six group E retinoblastoma eyes were evaluated. 3 eyes (50%) showed solid enhancement, 2 eyes (33.33%) had tram track pattern and 1 eye (16.66%) showed punctate enhancement pattern on CE-MRI. On histopathology, 5 (83.33%) cases showed PLONI and all 6 (100%) had ON head infiltration. The cut end of the ON was free in all cases. On correlating MRI and HPE, all eyes with solid enhancement pattern showed PLONI, of which 2/3 (66.6%) had diffuse ON infiltration. Only 50% of eyes with tram track patterns showed PLONI. The case which showed a punctate enhancement pattern showed focal infiltration by tumor cells with vacuolated cytoplasm on HPE. At the last follow-up, all patients were alive and free of disease.

Conclusion

ON enhancement patterns may make it more predictive for PLONI on HPE. Solid enhancement pattern appears to correlate better with the extent of ON invasion on HPE, and longer lengths of solid ON enhancement may be considered for neoadjuvant chemotherapy rather than upfront enucleation.

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.

Imaging Findings of Pediatric Orbital Masses and Tumor Mimics

Pediatric orbital masses are not common but encompass a wide spectrum of benign and malignant entities that range from developmental anomalies to primary and secondary orbital malignancies and metastatic disease. Certain orbital tumors are unique to pediatric patients, such as retinoblastoma and neuroblastoma. Clinical symptoms and signs are often insufficient to differentiate between orbital lesions, and imaging is essential for narrowing the diagnostic considerations and determining the most appropriate management strategy. MRI is the primary imaging modality for evaluating orbital masses in children, with US and CT playing complementary roles. The authors review a spectrum of masses and tumor mimics that affect the pediatric globe and orbit. The shared and differentiating characteristics of pediatric orbital lesions are reviewed. Emphasis is placed on utilizing an orbital compartment-based approach to narrow the differential diagnosis. By using this organizational scheme, the authors describe intraocular processes (retinoblastoma, persistent fetal vasculature, and Coats disease), intraconal lesions (lymphatic malformation, schwannoma, optic nerve sheath meningioma, and optic pathway glioma), extraconal lesions (infantile hemangioma, rhabdomyosarcoma, idiopathic orbital inflammation, lymphoma, venous varix, plexiform neurofibroma, and pleomorphic adenoma of the lacrimal gland), and lesions involving the bony orbit (dermoid cyst, metastatic neuroblastoma, and Langerhans cell histiocytosis). The authors describe the basic management of each entity. Orbital infections and traumatic lesions are beyond the scope of this article. ^©RSNA, 2022.

Correlation of clinical and radiological predictors of retinoblastoma with high-risk histopathological features

INTRODUCTION

Retinoblastoma (RB) tumors having high-risk histopathologic features (HRFs) have an increased risk of metastasis and disease relapse. However, RB has not been studied widely in Pakistan. Therefore, we evaluated the association of clinical, histopathologic, and radiological findings with HRFs in patients with RB who were treated at the Indus Health & Hospital Network in Karachi, Pakistan.

METHODS

We enrolled treatment-naïve patients with RB who received upfront enucleation from September 2017 to February 2021. We evaluated enucleated eyes with the Intraocular Classification of Retinoblastoma system and classified HRFs as invasion of the anterior chamber, including the iris and ciliary body, or massive invasion of the choroid, sclera, or optic nerve (postlaminar and/or up to the transection line).

RESULTS

Of 117 patients with RB treated at our institution during the study period, 54 received upfront enucleation. Unilateral disease was present in 92.6% of cases. The most frequent disease signs and symptoms included the presence of vitreous seeds (30.6%) and leukocoria (100%), respectively. The most frequent HRFs and radiological findings comprised massive choroidal invasion (15.1%) and anterior chamber enhancement (66.7%), respectively. The majority (62.9%) of patients did not exhibit any HRFs. Female sex, pseudohypopyon, iris neovascularization, buphthalmos, and glaucoma had significant predictive ability for HRF occurrence.

CONCLUSION

Pseudohypopyon, iris neovascularization, buphthalmos, and glaucoma are important clinical factors that should be taken into consideration before the management of RB. Early recognition of high-risk histopathological and radiological features is essential for appropriate treatment of RB.

Anterior chamber enhancement predicts optic nerve infiltration in retinoblastoma

OBJECTIVES

As described recently, intravenously injected gadolinium-based contrast agent (GBCA) penetrates into the anterior eye chamber (AC) and is drained from the retina to the distal optic nerve (ON) along perivascular spaces, which serves retinal homeostasis and was termed the orbital glymphatic system (GS). Independently, AC enhancement predicted ON infiltration, a major risk factor for advanced retinoblastoma (RB), in a small RB patient cohort. We aimed to review the supposed imaging biomarker for ON infiltration in a large RB cohort and with respect to the recently described orbital GS.

METHODS

This IRB-approved retrospective single-center study encompassed 539 orbital MRIs performed with an orbital coil and with the children under general anesthesia. Differences of signal intensity ratios (∆SIRs) of the AC to the lens were determined between non-contrast and GBCA-enhanced T1-weighted images and were correlated with histopathologic presence of ON infiltration.

RESULTS

∆SIR of the RB eye was an independent, significant predictor for ON invasion in multivariate analysis with adjustment for tumor size (p < 0.05) and increased with infiltration level.

CONCLUSIONS

GBCA enhancement of the AC predicts ON infiltration. This might be caused by impairment of the orbital glymphatic system, which is supposed to clear toxic metabolites from the retina to the postlaminar ON. In RB with ON infiltration, this efflux path is likely to be inhibited, which is supposed to result in disturbed retinal homeostasis, release of vascular endothelial growth factor, and iris neovascularization, which increases penetration of GBCA into the AC.

KEY POINTS

• Infiltration of the optic nerve can be predicted by anterior chamber enhancement after intravenous MRI contrast agent administration. • Increased anterior chamber enhancement in retinoblastoma with optic nerve infiltration might result from dysfunction of the orbital glymphatic system with disturbance of retinal homeostasis and consecutive iris neovascularization.

Response criteria for intraocular retinoblastoma: RB-RECIST

Standardized guidelines for assessing tumor response to therapy are essential for designing and conducting clinical trials. The Response Evaluation Criteria In Solid Tumors (RECIST) provide radiological standards for assessment of solid tumors. However, no such guidelines exist for the evaluation of intraocular cancer, and ocular oncology clinical trials have largely relied on indirect measures of therapeutic response-such as progression-free survival-to evaluate the efficacy of treatment agents. Herein, we propose specific criteria for evaluating treatment response of retinoblastoma, the most common pediatric intraocular cancer, and emphasize a multimodal imaging approach for comprehensive assessment of retinoblastoma tumors in clinical trials.

Imaging of the Primary Visual Pathway based on Visual Deficits

Vision loss can occur due to a variety of etiologies along the primary visual pathway. Understanding the anatomic organization of the visual pathway, which spans the globe to the occipital cortex, can help tailor neuroimaging to identify the cause of visual dysfunction. In this review, relevant anatomy and optimization of computed tomography and magnetic resonance imaging techniques will be described. This will be followed by a discussion of imaging findings related to pathologies at each functional anatomic level.

Accuracy of Computed Tomography and Magnetic Resonance Imaging for Detection of Pathologic Risk Factors in Patients Diagnosed with Retinoblastoma

Aim: To assess and compare the diagnostic accuracy of magnetic resonance imaging (MRI) and computed tomography (CT) for detecting the extent of tumor invasion in eyes with advanced retinoblastoma prior to enucleation using histopathologic analysis as a reference.Methods: A total of 56 patients (68 eyes) enucleated for retinoblastoma were reviewed. Eyes with complete data (CT 28, MRI 16) were included for analysis. Imaging data were reviewed by a pediatric radiologist, blinded to histopathology results. Four high-risk factors which included scleral, choroidal, anterior eye segment invasion, and postlaminar optic nerve invasion were assessed.Results: For CT, the diagnostic odds ratio (DOR), sensitivity, and specificity for detecting postlaminar optic nerve invasion were 1.7%, 25%, and 83.3%. Choroidal invasion was correctly identified in only 2 of 10 eyes (DOR 0.5, sensitivity 20%, specificity 66.7%). For scleral invasion, CT showed a diagnostic ratio of 1.5%, sensitivity 40%, specificity 69.6% whereas for anterior segment invasion DOR was 9.2%, sensitivity 100%, and specificity 65.4%. MRI showed a higher DOR for detecting postlaminar optic nerve invasion of 39%, sensitivity 77.8%, and specificity 100%. Choroidal and scleral invasion on MRI had a DOR of 6.5% (sensitivity 25%, specificity 100%) and 6% (sensitivity 33.3%, specificity 92.3%) respectively while DOR for anterior segment invasion was 1.3% (sensitivity 50%, specificity 57.1%).Conclusion: CT showed a poor diagnostic accuracy for all four high-risk factors in advanced retinoblastoma and therefore may not be a useful tool for assessment of tumor extension. For MRI, detection of postlaminar optic nerve invasion was moderately accurate although less accurate for detection of other risk factors. Decision-making for each child should not be based on any single parameter but rather on consideration of clinical factors in combination with radiologic findings.

Retinoblastoma: What the Neuroradiologist Needs to Know

Retinoblastoma is the most common primary intraocular tumor of childhood. Accurate diagnosis at an early stage is important to maximize patient survival, globe salvage, and visual acuity. Management of retinoblastoma is individualized based on the presenting clinical and imaging features of the tumor, and a multidisciplinary team is required to optimize patient outcomes. The neuroradiologist is a key member of the retinoblastoma care team and should be familiar with characteristic diagnostic and prognostic imaging features of this disease. Furthermore, with the adoption of intra-arterial chemotherapy as a standard of care option for globe salvage therapy in many centers, the interventional neuroradiologist may play an active role in retinoblastoma treatment. In this review, we discuss the clinical presentation of retinoblastoma, ophthalmic imaging modalities, neuroradiology imaging features, and current treatment options.

Diagnostic performance of MRI of post-laminar optic nerve invasion detection in retinoblastoma: A systematic review and meta-analysis

PURPOSE

Preoperative MRI detection of post-laminar optic nerve invasion (PLONI) offers guidance in assessing the probability of total tumor resection, an estimation of the extent of surgery, and screening of candidates for eye-preserving therapies or neoadjuvant chemotherapies in the patients with retinoblastoma (RB). The purpose of this systematic review and meta-analysis was to evaluate the diagnostic performance of MRI for detecting PLONI in patients with RB and to demonstrate the factors that may influence the diagnostic performance.

METHODS

Ovid-MEDLINE and EMBASE databases were searched up to January 11, 2020, for studies identifying the diagnostic performance of MRI for detecting PLONI in patients with RB. The pooled sensitivity and specificity of all studies were calculated followed by meta-regression analysis.

RESULTS

Twelve (1240 patients, 1255 enucleated globes) studies were included. The pooled sensitivity was 61%, and the pooled specificity was 88%. Higgins I² statistic demonstrated moderate heterogeneity in the sensitivity (I² = 72.23%) and specificity (I² = 78.11%). Spearman correlation coefficient indicated the presence of a threshold effect. In the meta-regression, higher magnetic field strength (3 T than 1.5 T), performing fat suppression, and thinner slice thickness (< 3 mm) were factors causing heterogeneity and enhancing diagnostic power across the included studies.

CONCLUSIONS

MR imaging was demonstrated to have acceptable diagnostic performance in detecting PLONI in patients with RB. The variation in the magnetic field strength and protocols was the main factor behind the heterogeneity across the included studies. Therefore, there is room for developing and optimizing the MR protocols for patients with RB.

Accuracy of preoperative imaging in predicting optic nerve invasion in retinoblastoma: A retrospective study

Purpose:

Optic nerve invasion is an important cause of mortality in retinoblastoma. We aimed correlate preoperative imaging and surgical histopathology findings in enucleated eyes with retinoblastoma to determine the efficacy of preoperative imaging in predicting optic nerve invasion in retinoblastoma.

Methods:

A retrospective review of records of all patients undergoing primary enucleation for retinoblastoma at a tertiary eyecare system between March 2013 and December 2017 with all patients having undergone preoperative imaging, either CT scan or MRI. Data was analyzed statistically to determine the correlation between preoperative CT scan/MRI and histopathology.

Results:

Totally, 97 eyes of 97 patients were included in the study who underwent primary enucleation for unilateral retinoblastoma. The average age at presentation was 27.8 months with the chief complaint being leukocoria in all the cases. 14 patients (14.43%) had evidence of optic nerve involvement in preoperative imaging. 30 patients had optic nerve invasion on histopathology (laminar and retrolaminar). Spearman's rank correlation test revealed a significant correlation between MRI findings and HP and an insignficant correlation between CT findings and HP. The CT scan had a sensitivity of 20%, specificity of 88.89%, 50% positive predictive value and 66.67% negative predictive value. MRI had a sensitivity of 40%, specificity of 93.55%, positive predictive value of 66.67% and a negative predictive value of 82.86%.

Conclusion:

MRI showed significant moderate correlation with surgical histopathology for predicting optic nerve invasion in retinoblastoma whereas CT shows insignificant correlation with HPE. Therefore, we recommend MRI for predicting optic nerve invasion in cases of retinoblastoma.

Epidemiological profile of retinoblastoma in North India: Implications for primary care and family physicians

Background:

Retinoblastoma is the most common primary intraocular malignancy among children. Despite being curable in early stages, majority of the cases in India present in late stages, when outcomes are very poor.

Objectives:

The aim of this study was to assess the epidemiological profile, clinical characteristics, and treatment practices among retinoblastoma patients in north India.

Materials and Methods:

Data on all patients with retinoblastoma, over a 10-year-time period from 2009 to 2018, who were treated in a tertiary care hospital in north India, were assessed. Data were analyzed to describe the demographic characteristics, clinical features in terms of stage at presentation, and management practices in terms of diagnostic investigations and treatment. The statistical significance for difference in percentages was assessed using Fischer's exact test at a 5% significance level.

Results:

A total of 25 retinoblastoma patients were enlisted, of whom one was excluded as it was adult onset retinoblastoma. The median age at presentation was 3 years, with a male to female ratio of 1:1.4. Bilateral presentation was seen in 16.6% cases. Majority (66.6%) of the patients underwent magnetic resonance imaging of brain and orbit as a part of the diagnostic workup. Intraocular disease was seen in 58.3% patients, whereas 41.6% patients had extraocular disease. Local therapy with vision preservation could be used only in 8.3% patients, whereas 87.5% patients were referred for enucleation. Chemotherapy with combination of vincristine, etoposide, and carboplatin was used extensively both, in neoadjuvant setting (83.3%) and in the adjuvant setting.

Conclusion:

Despite availability of treatment for eye preservation, its utility is limited due to the advanced stage at presentation. Awareness about the disease and its symptoms for early diagnosis, especially with the Mid-Level Health Provider at Health and Wellness Centers, is likely to improve early reporting and treatment and meeting the Vision 2020 goals.

Evaluation of the role of ultrasound biomicroscopy in advanced retinoblastoma: A prospective study on Asian Indian children

Aim: To evaluate the role of ultrasound biomicroscopy (UBM) in retinoblastoma (RB).Methods: Children with advanced unilateral RB were included. UBM was performed to look for tumour invasion into the anterior segment (AS) and for evaluation of quantitative parameters. Enucleation was done and UBM findings were correlated with histopathology. The main outcome measures were sensitivity and specificity of UBM for detecting AS invasion and comparison of quantitative parameters between the tumour affected and fellow eyes.Results: Fifty patients were evaluated. The mean age was 2.76 ± 1.63 years. Enucleation was performed in 50 eyes. The sensitivity and specificity of UBM for AS invasion were 80% (95% CI, 44-97%) and 95% (95% CI, 83-99%), respectively. UBM showed a sensitivity and specificity of 100% (95% CI, 59-100%) and 95% (95% CI, 84-99%), respectively, for iris invasion, 88% (95% CI, 47-100%) and 100% (95% CI, 92-100%), respectively, for ciliary body invasion, and 63% (95% CI, 24-91%) and 100% (95% CI, 92-100%), respectively, for anterior chamber (AC) angle invasion. Quantitative parameters were studied in 100 eyes. As compared to the fellow eyes, the AC angle was narrow (p < 0.05), posterior chamber was shallow (p = 0.004) and zonular length was increased (p = 0.001) in RB eyes.Conclusion: This clinicopathological study provides valuable insights into the role of UBM for evaluation of anterior extension of RB and for assessment of architectural changes in the AS due to the tumour.

Diagnosis of Postlaminar Optic Nerve Invasion in Retinoblastoma With MRI Features

BACKGROUND

Retinoblastomas (RBs) with postlaminar optic nerve invasion (PLONI) increases the risk of local recurrence or systemic metastasis. Most MRI studies on PLONI focused on optic nerve enhancement and tumor size, with reported relatively high specificity (84-98%) but low sensitivity (37-78%), which shows room for improvement, especially with regard to sensitivity.

PURPOSE

To evaluate the diagnostic performance for detecting PLONI with RB using MRI features.

STUDY TYPE

Retrospective.

POPULATION

Fifty patients with histopathologic PLONI and 70 patients without PLONI of RB.

FIELD STRENGTH/SEQUENCE

1.5T and 3.0T, precontrast axial T₁ -weighted and T₂ -weighted, postcontrast axial, coronal and oblique-sagittal T₁ -weighted.

ASSESSMENT

The eyes were histopathologically analyzed and the preoperative MRI features of the eyes were independently evaluated by three observers.

STATISTICAL TESTS

MRI features suggesting the presence of PLONI were identified by univariate and multivariable analysis. Receiver operating characteristic curve (ROC) and the area under the curve (AUC) were used to analyze diagnostic performance.

RESULTS

Significant independent diagnostic factors for PLONI include: 1: Bilateral tumor (odds ratio [OR], 15.32; 95% confidence interval [CI]: 1.63-143.51); 2: Tumor with total coverage of the optic disk (OR, 6.43; 95% CI: 1.04-39.79); and 3: Optic nerve enhancement (OR, 8.43; 95% CI: 3.50-20.31). On the other hand, isointense signal of tumor on T₂ WI (OR, 0.30; 95% CI: 0.12-0.75) was an independent diagnostic factor in excluding PLONI. ROC analysis showed AUC of 0.84 (95% CI: 0.77-0.91, P < 0.0001) for PLONI. Based on the cutoff of maximum Youden index, the sensitivity, specificity, and accuracy were 82%, 73%, and 77%, respectively.

DATA CONCLUSION

MRI features of RB showed a strong association with PLONI. The model of MRI features demonstrated promising diagnostic performance in detecting PLONI.

LEVEL OF EVIDENCE

4 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:1045-1052.

Magnetic resonance imaging for tumor restaging after chemotherapy in retinoblastoma with optic nerve invasion

PURPOSE

Extraocular retinoblastoma with optic nerve invasion is treated by a multimodal protocol consisting of neoadjuvant chemotherapy, enucleation, and adjuvant therapy. This study was conducted to evaluate the performance of magnetic resonance imaging (MRI) used for tumor restaging in these children after systemic chemotherapy administration.

METHODS

Contrast-enhanced MRI scan of orbits and brain was performed at diagnosis and patients were treated with neoadjuvant chemotherapy. After chemotherapy, MRI scan was repeated for tumor restaging and residual post-laminar thickening and/or enhancement of the affected optic nerve, if any, was recorded. MRI findings were correlated with histopathology in enucleated specimens. The main outcome measures were specificity, sensitivity, and accuracy of MRI in predicting post-laminar invasion after neoadjuvant chemotherapy.

RESULTS

A total of 46 eyes (46 patients) were studied. Optic nerve thickening on MRI had a sensitivity, specificity, and accuracy of 100% (95% Confidence Interval (CI): 64.6-100%), 76.9% (95% CI: 61.7-87.4%), and 80.4% (95% CI: 66.8-89.4%), respectively. Optic nerve enhancement had a sensitivity, specificity, and accuracy of 85.7% (95% CI: 48.7-97.4%), 79.5 % (95% CI: 64.5-89.2%), and 80.4% (95% CI: 66.8-89.4%), respectively. Combined thickening and enhancement of the optic nerve had a sensitivity, specificity, and accuracy of 100% (95% CI: 60.9-100%), 82.4% (95% CI: 66.5-91.7%), and 85% (95% CI: 70.9-92.9%), respectively.

CONCLUSION

MRI is a valuable tool for restaging of retinoblastoma and predicting residual optic nerve disease after neoadjuvant chemotherapy. Combined thickening and enhancement on MRI appeared to be a more reliable indicator of post-laminar invasion as compared to thickening or enhancement alone.

The predictive value of magnetic resonance imaging of retinoblastoma for the likelihood of high-risk pathologic features

PURPOSE:

To evaluate the predictive value of magnetic resonance imaging in retinoblastoma for the likelihood of high-risk pathologic features.

METHODS:

A retrospective study of 64 eyes enucleated from 60 retinoblastoma patients. Contrast-enhanced magnetic resonance imaging was performed before enucleation. Main outcome measures included demographics, laterality, accuracy, sensitivity, and specificity of magnetic resonance imaging in detecting high-risk pathologic features.

RESULTS:

Optic nerve invasion and choroidal invasion were seen microscopically in 34 (53%) and 28 (44%) eyes, respectively, while they were detected in magnetic resonance imaging in 22 (34%) and 15 (23%) eyes, respectively. The accuracy of magnetic resonance imaging in detecting prelaminar invasion was 77% (sensitivity 89%, specificity 98%), 56% for laminar invasion (sensitivity 27%, specificity 94%), 84% for postlaminar invasion (sensitivity 42%, specificity 98%), and 100% for optic cut edge invasion (sensitivity100%, specificity 100%). The accuracy of magnetic resonance imaging in detecting focal choroidal invasion was 48% (sensitivity 33%, specificity 97%), and 84% for massive choroidal invasion (sensitivity 53%, specificity 98%), and the accuracy in detecting extrascleral extension was 96% (sensitivity 67%, specificity 98%).

CONCLUSIONS AND RELEVANCE:

Magnetic resonance imaging should not be the only method to stratify patients at high risk from those who are not, eventhough it can predict with high accuracy extensive postlaminar optic nerve invasion, massive choroidal invasion, and extrascleral tumor extension.

MR Imaging Features of Retinoblastoma: Association with Gene Expression Profiles

Purpose To identify associations between magnetic resonance (MR) imaging features and gene expression in retinoblastoma. Materials and Methods A retinoblastoma MR imaging atlas was validated by using anonymized MR images from referral centers in Essen, Germany, and Paris, France. Images were from 39 patients with retinoblastoma (16 male and 18 female patients [the sex in five patients was unknown]; age range, 5-90 months; inclusion criterion: pretreatment MR imaging). This atlas was used to compare MR imaging features with genome-wide messenger RNA (mRNA) expression data from 60 consecutive patients obtained from 1995 to 2012 (35 male patients [58%]; age range, 2-69 months; inclusion criteria: pretreatment MR imaging, genome-wide mRNA expression data available). Imaging pathway associations were analyzed by means of gene enrichment. In addition, imaging features were compared with a predefined gene expression signature of photoreceptorness. Statistical analysis was performed with generalized linear modeling of radiology traits on normalized log2-transformed expression values. P values were corrected for multiple hypothesis testing. Results Radiogenomic analysis revealed 1336 differentially expressed genes for qualitative imaging features (threshold P = .05 after multiple hypothesis correction). Loss of photoreceptorness gene expression correlated with advanced stage imaging features, including multiple lesions (P = .03) and greater eye size (P < .001). The number of lesions on MR images was associated with expression of MYCN (P = .04). A newly defined radiophenotype of diffuse-growing, plaque-shaped, multifocal tumors displayed overexpression of SERTAD3 (P = .003, P = .049, and P = .06, respectively), a protein that stimulates cell growth by activating the E2F network. Conclusion Radiogenomic biomarkers can potentially help predict molecular features, such as photoreceptorness loss, that indicate tumor progression. Results imply a possible role for radiogenomics in future staging and treatment decision making in retinoblastoma.

The value of MRI in evaluating the efficacy and complications with the treatment of intra-arterial chemotherapy for retinoblastoma

Retinoblastoma is the most common intraocular malignant tumor of childhood. Intra-arterial chemotherapy (IAC) is a recently popularized technique used for the treatment of retinoblastoma, to decrease mortality, increase preservation of the eye, and prevent blindness. Along with the extensive use of IAC, it is important to apply noninvasive examination methods to assess the activity of the tumor and the risk factors for disease dissemination without histopathological confirmation. There are few studies that have assessed the value of magnetic resonance imaging (MRI) in evaluating the efficacy and complications of IAC for retinoblastoma. We retrospectively analyzed the MRI features of 60 patients with unilateral retinoblastoma given the primary treatment of IAC from January 2014 to February 2016 in our hospital. Our study showed that MRI could well assess the decreased activity of the tumor after IAC, presenting with diminished tumor size, increased apparent diffusion coefficient (ADC) values (from 0.94 ± 0.24 × 10-3 mm2/s to 2.24 ± 0.40 × 10-3 mm2/s), and a reduced degree of enhancement of the tumor. Our study also showed that MRI can monitor the risk factors of abnormal enhancement of the postlaminar optic nerve, to avoid unnecessary enucleation. Meanwhile, the results showed that the main late complications after IAC included affected eyeball volume reduction, subretinal hemorrhage, vitreous hemorrhage, vitreous opacity, cataractous len, and choroidal vascular ischemia.

Magnetic Resonance Imaging in Orbital Pathologies: A Pictorial Review

Orbital lesions form a wide range of pathologies, that create challenges in diagnosis, management, and treatment. The high-resolution soft tissue detail provided by magnetic resonance imaging (MRI) has allowed for better lesion characterization. Especially in cases where history and clinical evaluation are insufficient, MRI plays a crucial role. MRI is also important in the detection of the extent of orbital diseases. The aim of this study was to examine the MRI characteristics of common and/or rare diseases arising from or extending into the orbita to aid radiologists in the correct diagnosis of orbital lesions.

9.4T and 17.6T MRI of Retinoblastoma: Ex Vivo evaluation of microstructural anatomy and disease extent compared with histopathology

BACKGROUND

Retinoblastoma is the most common intraocular tumor in childhood with a good prognosis in terms of mortality, but detailed information about tumor morphology and disease extent in retinoblastoma is important for treatment decision making.

PURPOSE

To demonstrate ultrahigh-field MRI tumor morphology and tumor extent in retinoblastoma correlating with in and ex vivo images with histopathology.

STUDY TYPE

Prospective case series.

POPULATION

Six retinoblastoma patients (median age 5.5 months, range 2-14) were prospectively included in this study. Median time between diagnosis and enucleation was 8 days (range 7-19).

FIELD STRENGTH/SEQUENCE

In vivo pre-enucleation at 1.5T MRI with a circular surface coil. Ex vivo imaging (FLASH T₁ -weighted and RARE T₂ -weighted) was performed at field strengths of 9.4T and 17.6T.

ASSESSMENT

After ex vivo imaging, the eyes were histopathologically analyzed and morphologically matched with MRI findings by three authors (two with respectively 14 and 4 years of experience in ocular MRI and one with 16 years of experience in ophthalmopathology).

RESULTS

Small submillimeter morphological aspects of intraocular retinoblastoma were successfully depicted with higher-resolution MRI and matched with histopathology images. With ex vivo MRI a small subretinal tumor seed (300 μm) adjacent to the choroid was morphologically matched with histopathology. Also, a characteristic geographical pattern of vital tumor tissue (400 μm) surrounding a central vessel interspersed with necrotic areas correlated with histopathology images. Tumor invasion into the optic nerve showed a higher signal intensity on T₁ -weighted higher-resolution MRI.

DATA CONCLUSION

Higher-resolution MRI allows for small morphological aspects of intraocular retinoblastoma and extraocular disease extent not visible on currently used clinical in vivo MRI to be depicted.

LEVEL OF EVIDENCE

4 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:1487-1497.

Correlation between conventional MR imaging combined with diffusion-weighted imaging and histopathologic findings in eyes primarily enucleated for advanced retinoblastoma: a retrospective study

OBJECTIVES

To determine the diagnostic accuracy of conventional MRI in detecting tumour invasion of advanced intraocular retinoblastoma and to correlate ADC values with high-risk prognostic parameters.

METHOD

The sensitivities, specificities, positive predictive values (PPV), negative predictive values (NPV) and accuracies of MRI in detecting tumour-extent parameters of 63 retinoblastomas were determined. Furthermore, ADC values were correlated with high-risk prognostic parameters.

RESULTS

MRI detected postlaminar optic nerve with a sensitivity of 73.3% (95% CI 44.9-92.2%) and a specificity of 89.6% (77.3-96.5%), while the specificity for choroidal invasion was only 31.8% (13.9-54.9%). Likewise, MRI failed to predicted early optic nerve invasion in terms of low sensitivity and PPV. In contrast, scleral and ciliary body invasion could be correctly excluded with high NPV. ADC values were significantly lower in patients with undifferentiated tumours, large tumour size, as with optic nerve and scleral invasion (all p < 0.05). However, no correlation was found between ADC values and the degree of choroidal or ciliary body infiltration. Additionally, ADC values were negatively correlated with Ki-67 index (r = -0.62, P = 0.002).

CONCLUSIONS

Conventional MRI has some limitations in reliably predicting microscopic infiltration, with the diagnostic efficiency showing room for improvement, whereas ADC values correlated well with certain high-risk prognostic parameters for retinoblastoma.

KEY POINTS

• Conventional MRI failed to predicted microscopic infiltration of the retinoblastoma. • Scleral and ciliary body invasion could be excluded with high NPV. • ADC values correlated well with some high-risk pathological prognostic parameters.

Diagnostic Accuracy of Intraocular Tumor Size Measured with MR Imaging in the Prediction of Postlaminar Optic Nerve Invasion and Massive Choroidal Invasion of Retinoblastoma

Purpose To assess the correlation of intraocular retinoblastoma tumor size measured with magnetic resonance (MR) imaging in the prediction of histopathologically determined metastatic risk factors (postlaminar optic nerve invasion and massive choroidal invasion). Materials and Methods The ethics committee approved this retrospective multicenter study with a waiver of informed consent. The study population included 370 consecutive patients with retinoblastoma (375 eyes) who underwent baseline MR imaging, followed by primary enucleation from 1993 through 2014. Tumor sizes (maximum diameter and volume) were measured independently by two observers and correlated with histopathologic risk factors. Receiver operating characteristic curves were used to analyze the diagnostic accuracy of tumor size, and areas under the curve were calculated. Logistic regression analysis was performed to evaluate potential confounders. Results Receiver operating characteristic analysis of volume and diameter, respectively, yielded areas under the curve of 0.77 (95% confidence interval [CI]: 0.70, 0.85; P < .0001) and 0.78 (95% CI: 0.71, 0.85; P < .0001) for postlaminar optic nerve invasion (n = 375) and 0.67 (95% CI: 0.57, 0.77; P = .0020) and 0.70 (95% CI: 0.59, 0.80; P = .0004) for massive choroidal tumor invasion (n = 219). For the detection of co-occurring massive choroidal invasion and postlaminar optic nerve invasion (n = 219), volume and diameter showed areas under the curve of 0.81 (95% CI: 0.70, 0.91; P = .0032) and 0.83 (95% CI: 0.73, 0.93; P = .0016), respectively. Conclusion Intraocular tumor size shows a strong association with postlaminar optic nerve invasion and a moderate association with massive choroidal invasion. These findings provide diagnostic accuracy measures at different size cutoff levels, which could potentially be useful in a clinical setting, especially within the scope of the increasing use of eye-salvage treatment strategies. (©) RSNA, 2015 Online supplemental material is available for this article.

MRI helps depict clinically undetectable risk factors in advanced stage retinoblastomas

This study compared high-resolution MRI with histology in advanced stage retinoblastomas in which ophthalmoscopy and ultrasonography did not give an exhaustive depiction of the tumour and/or its extension. MRI of orbits and head in 28 retinoblastoma patients (28 eyes) treated with primary enucleation were evaluated. Iris neoangiogenesis, infiltrations of optic nerve, choroid, anterior segment and sclera suspected at MR and histology were compared. Abnormal anterior segment enhancement (AASE) was also correlated with histologically proven infiltrations. Brain images were also evaluated. Significant values were obtained for: prelaminar optic nerve (ON) sensitivity (0.88), positive predictive value (PPV) (0.75) and negative predictive value (NPV) (0.71); post-laminar ON sensitivity (0.50), specificity (0.83), PPV (0.50) and NPV (0.83); overall choroid sensitivity (0.82), and massive choroid NPV (0.69); scleral specificity (1), and NPV (1). AASE correlated with iris neoangiogenesis in 14 out of 19 eyes, and showed significant values for: overall ON PPV (0.65), prelaminar ON sensitivity (0.65), and PPV (0.61), post-laminar ON NPV (0.64); overall choroid sensitivity (0.77), PPV (0.59) and NPV (0.73); scleral NPV (0.83); anterior segment sensitivity (1), and NPV (1). Odds ratios (OR) and accuracy were significant in scleral and prelaminar optic nerve infiltration. Brain examination was unremarkable in all cases. High-resolution MRI may add important findings to clinical evaluation of advanced stage retinoblastomas.

Automatic Segmentation of the Eye in 3D Magnetic Resonance Imaging: A Novel Statistical Shape Model for Treatment Planning of Retinoblastoma

PURPOSE

Proper delineation of ocular anatomy in 3-dimensional (3D) imaging is a big challenge, particularly when developing treatment plans for ocular diseases. Magnetic resonance imaging (MRI) is presently used in clinical practice for diagnosis confirmation and treatment planning for treatment of retinoblastoma in infants, where it serves as a source of information, complementary to the fundus or ultrasonographic imaging. Here we present a framework to fully automatically segment the eye anatomy for MRI based on 3D active shape models (ASM), and we validate the results and present a proof of concept to automatically segment pathological eyes.

METHODS AND MATERIALS

Manual and automatic segmentation were performed in 24 images of healthy children's eyes (3.29 ± 2.15 years of age). Imaging was performed using a 3-T MRI scanner. The ASM consists of the lens, the vitreous humor, the sclera, and the cornea. The model was fitted by first automatically detecting the position of the eye center, the lens, and the optic nerve, and then aligning the model and fitting it to the patient. We validated our segmentation method by using a leave-one-out cross-validation. The segmentation results were evaluated by measuring the overlap, using the Dice similarity coefficient (DSC) and the mean distance error.

RESULTS

We obtained a DSC of 94.90 ± 2.12% for the sclera and the cornea, 94.72 ± 1.89% for the vitreous humor, and 85.16 ± 4.91% for the lens. The mean distance error was 0.26 ± 0.09 mm. The entire process took 14 seconds on average per eye.

CONCLUSION

We provide a reliable and accurate tool that enables clinicians to automatically segment the sclera, the cornea, the vitreous humor, and the lens, using MRI. We additionally present a proof of concept for fully automatically segmenting eye pathology. This tool reduces the time needed for eye shape delineation and thus can help clinicians when planning eye treatment and confirming the extent of the tumor.

Imaging of pediatric pathology during the Iraq and Afghanistan conflicts

United States Armed Forces radiologists deployed to Afghanistan and Iraq in modern military conflicts may encounter pediatric patients as a casualty of war or when providing humanitarian assistance to the indigenous population. Pediatric patients account for 4-7% of admissions at U.S. military hospitals during the Iraq and Afghanistan conflicts. It is pertinent for radiologists in the humanitarian care team to be familiar with imaging pediatric trauma patients, the pathology endemic to the local population, and delayed presentations of congenital and developmental disorders to adequately care for these patients. The radiological manifestations of various pediatric disorders seen in the setting of the Iraq and Afghanistan conflicts will be explored.

Common pediatric head and neck congenital/developmental anomalies

Pediatric head and neck neuroradiology is a broad and complex topic. This article focuses on several of the common and sometimes challenging pediatric head and neck congenital/developmental anomalies physicians may encounter in clinical practice. Although some diagnoses may be evident on physical examination, others may present a diagnostic dilemma. Patients may initially present with a variety of secondary findings. Imaging serves an important role in making a diagnosis, guiding referral, and in some cases even providing treatment options through interventional radiology. Key diagnostic criteria and critical points of interest for each diagnosis are presented.

Assessment of early-stage optic nerve invasion in retinoblastoma using high-resolution 1.5 Tesla MRI with surface coils: a multicentre, prospective accuracy study with histopathological correlation

OBJECTIVES

To assess the accuracy of high-resolution (HR) magnetic resonance imaging (MRI) in diagnosing early-stage optic nerve (ON) invasion in a retinoblastoma cohort.

METHODS

This IRB-approved, prospective multicenter study included 95 patients (55 boys, 40 girls; mean age, 29 months). 1.5-T MRI was performed using surface coils before enucleation, including spin-echo unenhanced and contrast-enhanced (CE) T1-weighted sequences (slice thickness, 2 mm; pixel size <0.3 × 0.3 mm(2)). Images were read by five neuroradiologists blinded to histopathologic findings. ROC curves were constructed with AUC assessment using a bootstrap method.

RESULTS

Histopathology identified 41 eyes without ON invasion and 25 with prelaminar, 18 with intralaminar and 12 with postlaminar invasion. All but one were postoperatively classified as stage I by the International Retinoblastoma Staging System. The accuracy of CE-T1 sequences in identifying ON invasion was limited (AUC = 0.64; 95 % CI, 0.55 - 0.72) and not confirmed for postlaminar invasion diagnosis (AUC = 0.64; 95 % CI, 0.47 - 0.82); high specificities (range, 0.64 - 1) and negative predictive values (range, 0.81 - 0.97) were confirmed.

CONCLUSION

HR-MRI with surface coils is recommended to appropriately select retinoblastoma patients eligible for primary enucleation without the risk of IRSS stage II but cannot substitute for pathology in differentiating the first degrees of ON invasion.

KEY POINTS

• HR-MRI excludes advanced optic nerve invasion with high negative predictive value. • HR-MRI accurately selects patients eligible for primary enucleation. • Diagnosis of early stages of optic nerve invasion still relies on pathology. • Several physiological MR patterns may mimic optic nerve invasion.

[Retinoblastoma: recent advances]

Retinoblastoma is the most common intraocular malignancy of infancy with an incidence of 1/15,000 to 1/20,000 births. Sixty percent of retinoblastomas are unilateral, with a median age at diagnosis of two years, and in most cases are not hereditary. Retinoblastoma is bilateral in 40% of cases, with an earlier median age at diagnosis of one year. All bilateral and multifocal unilateral forms are hereditary and are part of a genetic cancer predisposition syndrome. All children with a bilateral or familial form, and 10 to 15% of children with an unilateral form, constitutionally carry an RB1 gene mutation. The two most frequent symptoms revealing retinoblastoma are leukocoria and strabismus. Diagnosis is made by fundoscopy, with ultrasound and magnetic resonance imaging (MRI) contributing both to diagnosis and assessment of the extension of the disease. Treatment of patients with retinoblastoma must take into account the various aspects of the disease (unilateral/bilateral, size, localization…), the risk to vision and the possible hereditary nature of the disease. The main prognostic aspects are still premature detection and adapted coverage by a multi-disciplinary specialized team. Enucleation is still often necessary in unilateral disease; the decision for adjuvant treatment is taken according to the histological risk factors. The most important recent therapeutic advances concern the conservative treatment which is proposed for at least one of the two eyes in most bilateral cases: laser alone or in combination with chemotherapy, cryotherapy or brachytherapy. Recently, the development of new conservative techniques of treatment, such as intra-arterial selective chemotherapy perfusion, aims at preserving visual function in these children and decreasing the number of enucleations and the need for external beam radiotherapy. The vital prognosis related to retinoblatoma is now excellent in industrialized countries, but long-term survival is still related to the development of secondary tumors, mainly secondary sarcoma. Retinoblastoma requires multi-disciplinary care as well as a long term specialized follow-up. Early counseling of patients and their family concerning the risk of transmission of the disease and the risk of development of secondary tumors is necessary.

Diagnostic image quality of gadolinium-enhanced T1-weighted MRI with and without fat saturation in children with retinoblastoma

BACKGROUND

Gadolinium-enhanced T1-weighted MRI without fat saturation has been recommended for assessment of retinoblastoma.

OBJECTIVE

The purpose of this study was to compare diagnostic image quality without and with fat saturation following gadolinium administration.

MATERIALS AND METHODS

High-resolution gadolinium-enhanced T1-weighted sequences with and without fat saturation performed in children with subsequently histopathologically confirmed retinoblastoma were included. Image analysis (image quality [1 = poor, 2 = moderate, 3 = good], anatomical detail depiction, tumour extension) was performed by two neuroradiologists in consensus. Enhancement was scored and measured. Signal- and contrast-to-noise ratios were calculated. Image-assessed tumour invasiveness was compared to histopathological findings. Paired sample t-test was used for statistical analysis.

RESULTS

Thirty-six children (mean age, 19.0 ± 16.8 [SD] months) were included. Image quality and anatomical detail depiction were significantly better without fat saturation (P < 0.001). Tumour enhancement was rated higher with fat saturation (P < 0.001). Fat saturation improved detection of (post-)laminar optic nerve infiltration. Detection of choroidal invasion was improved without fat saturation. Combining both sequences was best in the assessment of tumour extension (sensitivity/specificity for (post-)laminar optic nerve infiltration, 75.0%/100.0%, and for choroidal invasion, 87.5%/85.7%).

CONCLUSION

Combined T1-weighted spin-echo imaging with and without fat saturation improved the image quality for assessment of invasiveness of retinoblastoma.

High-resolution MR imaging of the orbit in patients with retinoblastoma

Retinoblastoma is the most common intraocular childhood malignancy, with a prevalence of one in 18,000 children younger than 5 years old in the United States. In 80% of patients, retinoblastoma is diagnosed before the age of three, and in 95% of patients, retinoblastoma is diagnosed before the age of five. Although reports exist of retinoblastoma in adults, onset beyond 6 years of age is rare. Broadly, retinoblastoma may be classified into two groups: sporadic and heritable. In either case, the origin of the tumor is a biallelic mutation in primitive neuroepithelial cells. Although their details vary, several staging schemes are used to describe the extent of retinoblastoma according to the following four general criteria: intraocular location, extraocular (extraorbital) location, central nervous system disease, and systemic metastases. In the past decade, substantial changes have taken place in terms of staging and monitoring treatment in patients with retinoblastoma. Diagnosis and treatment of retinoblastoma involve a multidisciplinary approach, for which imaging is a vital component. Increasing awareness and concerns about the effects of radiation in patients with retinoblastoma have led to a shift away from external-beam radiation therapy and toward chemotherapy and locoregional treatment, as well as the establishment of magnetic resonance imaging as the most important imaging modality for diagnosis, staging, and treatment monitoring.

Comparison of the diagnostic value of MR imaging and ophthalmoscopy for the staging of retinoblastoma

PURPOSE

To compare the diagnostic value of magnetic resonance (MR) imaging and ophthalmoscopy for staging of retinoblastoma.

METHODS

MR and ophthalmoscopic images of 36 patients who underwent enucleation were evaluated retrospectively following institutional review board approval. Histopathology being the standard of reference, the sensitivity and specificity of both diagnostic modalities were compared regarding growth pattern, iris neoangiogenesis, retinal detachment, vitreous seeds and optic nerve invasion. Data were analysed via McNemar's test.

RESULTS

Both investigations showed no significant difference in accuracy for the detection of different tumour growth patterns (P = 0.80). Vitreous seeding detection was superior by ophthalmoscopy (P < 0.001). For prelaminar optic nerve invasion, MR imaging showed similar sensitivity as ophthalmoscopy but increased specificity of 40 % (CI 0.12-0.74) vs. 20 % (0.03-0.56). MR detected optic nerve involvement past the lamina cribrosa with a sensitivity of 80 % (0.28-0.99) and a specificity of 74 % (0.55-0.88). The absence of optic nerve enhancement excluded histopathological infiltration, but the presence of optic nerve enhancement included a high number of false positives (22-24 %).

CONCLUSIONS

Ophthalmoscopy remains the method of choice for determining extent within the globe while MR imaging is useful for evaluating extraocular tumour extension. Thus, both have their own strengths and contribute uniquely to the staging of retinoblastoma.

KEY POINTS

• Ophthalmoscopy: method of choice for determining extent of retinoblastoma within the globe. • MR imaging provides optimal evaluation of extrascleral and extraocular tumour extension. • Positive enhancement of the optic nerve on MRI does not necessarily indicate involvement.

In utero detection of retinoblastoma with fetal magnetic resonance and ultrasound: initial experience

Purpose Our aim was to evaluate and compare the ability of prenatal ultrasound (US) and fetal magnetic resonance imaging (MRI) to detect retinoblastoma lesions in utero. Methods Fetuses at risk for having bilateral retinoblastoma were enrolled in this prospective study. High-resolution US of the fetal eye was performed at 16 to 18 weeks' gestation, every 4 weeks until 32 weeks, then every 2 weeks until delivery. Fetal MRIs were performed every 8 weeks starting at 16 to 18 weeks of gestation. An exam under anesthesia (EUA) was performed postnatally, the gold standard of this study. Lesions were classified as being elevated or minimally elevated based upon their morphology. Results Of six fetuses suspected or confirmed to be at risk for developing bilateral retinoblastoma, one had tumors on her first postnatal EUA exam. A total of two minimally elevated lesions were seen by the EUA but not detected prenatally by imaging. One elevated lesion (2 mm in height) identified by postnatal EUA was initially identified by prenatal US. Fetal MRI did not detect any lesions. Conclusion Both prenatal US and fetal MRI are limited in the detection of minimally elevated retinoblastoma lesions. Prenatal US appears to be more sensitive than fetal MRI in the detection of elevated retinoblastoma lesions.

Can preoperative MR imaging predict optic nerve invasion of retinoblastoma?

PURPOSE

To evaluate the accuracy of pre-operative MRI for the detection of optic nerve invasion in retinoblastoma.

MATERIALS AND METHODS

Institutional review board approval and informed consent were waived for this retrospective study. A total of 41 patients were included. Inclusion criteria were histologically proven retinoblastoma, availability of diagnostic-quality preoperative MR images acquired during the 4 weeks before surgery, unilateral retinoblastoma, and normal-sized optic nerve. Two radiologists retrospectively reviewed the MR images independently. Five imaging findings (diffuse mild optic nerve enhancement, focal strong optic nerve enhancement, optic sheath enhancement, tumor location, and tumor size) were evaluated against optic nerve invasion of retinoblastoma. The predictive performance of all MR imaging findings for optic nerve invasion was also evaluated by the receiver operating characteristic curve analysis.

RESULTS

Optic nerve invasion was histopathologically confirmed in 24% of study population (10/41). The differences in diffuse mild enhancement, focal strong enhancement, optic sheath enhancement, and tumor location between patients with optic nerve invasion and patients without optic nerve invasion were not significant. Tumor sizes were 16.1mm (SD: 2.2mm) and 14.9 mm (SD: 3.6mm) in patients with and without optic nerve involvement, respectively (P=0.444). P-Values from binary logistic regression indicated that all five imaging findings were not significant predictors of tumor invasion of optic nerve. The AUC values of all MR imaging findings for the prediction of optic nerve invasion were 0.689 (95% confidence interval: 0.499-0.879) and 0.653 (95% confidence interval: 0.445-0.861) for observer 1 and observer 2, respectively.

CONCLUSION

Findings of MRI in patients with normal-sized optic nerves have limited usefulness in preoperatively predicting the presence of optic nerve invasion in retinoblastoma.

Abnormalities of the globe

Although much has been published in the radiology literature on the multitudinous conditions affecting the bony orbit, there has been relatively little on diseases confined to the globe itself. As current cross-sectional imaging techniques evolve, the globes can be visualized in ever greater detail, facilitating the recognition of even fairly subtle disease entities in this region. Indeed, the fact that high-resolution detailed images of this area are achievable without significant time or radiation penalty when evaluating surrounding structures means that incidental disease is not infrequently encountered. As such, common disease entities in this region are of interest to the general radiologist and the diagnosis of globe disease need not be the remit of experienced observers in specialist centres. At our institutions we have recently encountered a number of cases covering a broad spectrum of diagnoses including traumatic, neoplastic, iatrogenic, inflammatory, and infective aetiologies. The purpose of this review is to briefly revise the pertinent anatomical and physiological properties of the globe and to familiarize the reader with the computed tomography (CT) and magnetic resonance imaging (MRI) appearances of a number of these disease states. The collection of abnormalities included is not intended to be exhaustive, merely representative, with the emphasis towards those more commonly encountered.

Correlation of apparent diffusion coefficient at 3T with prognostic parameters of retinoblastoma

BACKGROUND AND PURPOSE

Pathologic prognostic parameters for retinoblastoma have been defined. Our purpose was to correlate ADC values at 3T with prognostic parameters of retinoblastoma.

MATERIALS AND METHODS

This study included 72 children (30 boys and 42 girls, mean age 19 ± 2.6 months) with retinoblastoma. Pretreatment diffusion-weighted MR imaging was performed on a 3T scanner with b factors of 0, 500, and 1000 seconds/mm(2). ADC values were calculated and pathologic specimens were analyzed. ADC values of the tumors were then correlated with prognostic parameters, including degree of histologic differentiation, tumor size, bilaterality, choroidal invasion, and optic nerve extension.

RESULTS

The mean ADC value of retinoblastoma was 0.49 ± 0.12 × 10(-3) mm(2)/s. The ADC values of well- and moderately differentiated tumors were significantly different (P = .007) from poorly and undifferentiated retinoblastoma. There was also a significant difference in the ADC value among small, medium, and large tumors (P = .015), as well as between unilateral and bilateral retinoblastoma (P = .001), and this was independent of the degree of differentiation. The ADC value was also significantly lower (P = .003) when optic nerve invasion was present. There was no correlation of ADC value with growth pattern or choroidal invasion (P = .640 and 0.661, respectively). The ADC value of retinoblastoma was well correlated with the degree of differentiation of the tumor (r = 0.87, P = .007) and inversely correlated with the size of the tumor (r = -0.68, P = .015).

CONCLUSIONS

ADC correlated with some of the accepted parameters of poor prognosis for retinoblastoma and may serve as a noninvasive prognostic parameter for assessment of newly diagnosed retinoblastoma.

Correlation between clinical features, magnetic resonance imaging, and histopathologic findings in retinoblastoma: a prospective study

OBJECTIVE

To correlate clinical features with histopathology findings in advanced intraocular retinoblastoma and to determine the diagnostic accuracy of magnetic resonance imaging (MRI) in detecting tumor invasion.

DESIGN

Prospective, nonrandomized case series.

PARTICIPANTS

We included 75 patients with group E retinoblastoma.

METHODS

Demographic and clinical features were recorded at presentation. Contrast-enhanced MRI was performed to study tumor characteristics and extent of invasion. Primary enucleation was performed and histopathologic features noted. Statistical analysis was done using the Kruskal-Wallis test to determine correlation between clinical features and histopathology. Sensitivity, specificity, and accuracy of MRI in detecting tumor invasion were determined.

MAIN OUTCOME MEASURES

Significant associations between clinical findings at presentation and high-risk histopathology, and correlation between MRI results and histopathologic evidence of tumor invasion.

RESULTS

A significant association was found between iris neovascularization and choroidal invasion (P = 0.032), intraocular pressure and optic nerve invasion (P = 0.034), and shallow anterior chamber and iris invasion (P = 0.021). Corneal diameter did not show any significant correlation with high-risk histopathology. On MRI, tumor volume showed a significant association with optic nerve invasion (P = 0.023). The accuracy of MRI in detecting choroidal invasion was 68% (sensitivity, 60%; specificity, 80%). Prelaminar invasion was correctly identified in 9 out of 15 eyes (accuracy, 84%; sensitivity, 60%; specificity, 90%), whereas the accuracy of MRI in detecting postlaminar invasion was 76% (sensitivity, 61.9%; specificity, 81.5%). Ciliary body invasion was correctly identified in 5 out of 7 eyes (accuracy, 93.3%; specificity, 95.6%) and scleral invasion in 5 out of 6 eyes (accuracy, 98.7%; specificity, 100%).

CONCLUSIONS

As far as we are aware, this is the first prospective study on the correlation of clinical features and MRI findings with histopathologic risk factors in eyes primarily enucleated for retinoblastoma. Neovascularization of iris, intraocular pressure, shallow anterior chamber, and tumor volume correlated well with high-risk histopathology. Because MRI has limitations in reliably predicting microscopic infiltration of the choroid and optic nerve, decision in favor of neoadjuvant chemotherapy on the basis of suspected postlaminar invasion on MRI is not justified in the absence of histopathologic evidence of disease.

Single-shot turbo spin-echo diffusion-weighted imaging for retinoblastoma: initial experience

BACKGROUND AND PURPOSE

Retinoblastoma may exhibit variable hyperintensities on DWI, resulting in different values in the ADC maps, depending on their histology and cellularity. However, EP-based DWI has susceptibility artifacts and image distortions, which make DWI of the orbit a challenging technique. The aim of this study was to investigate the feasibility of single-shot turbo spin-echo (HASTE) DWI in the evaluation of children with retinoblastoma and to assess the value of ADC maps in differentiating viable and necrotic tumor tissue.

MATERIALS AND METHODS

Two radiologists assessed conventional MR images, DWI, and ADC maps of 17 patients with retinoblastoma (n = 17 eyes). Non-EP DWI was performed by using a HASTE sequence with b-values of 0 and 1000 s/mm(2). ADC values were measured for enhancing and nonenhancing tumor tissue. ADC maps were compared with histopathologic findings regarding tumor differentiation and viability.

RESULTS

On DWI, vital tumor tissue showed hyperintensity with negligible intensity of surrounding vitreous. The difference in mean (range) ADC values between enhancing (1.03 [0.72-1.22] × 10(-3) mm(2) s(-1)) and nonenhancing (1.47 [0.99-1.80] × 10(-3) mm(2) s(-1)) parts of retinoblastoma was statistically significant (P < .0005). Nonenhancing tumor parts showed a significantly lower ADC compared with vitreous (2.67 [2.24-3.20]×10(-3) mm(2) s(-1)) (P < .0005) and subretinal fluid (2.20 [1.76-2.96] × 10(-3) mm(2) s(-1)) (P < .0005). Histopathologically, low ADC values (enhancing tumor part) correlated to viable tumor tissue, whereas intermediate ADC values (nonenhancing tumor parts) correlated to necrotic tumor tissue.

CONCLUSIONS

HASTE DWI allowed adequate characterization of retinoblastoma, and ADC is a helpful tool to differentiate viable and necrotic tumor tissue and might be valuable in monitoring the response to eye-preserving therapies.

Guidelines for imaging retinoblastoma: imaging principles and MRI standardization

Retinoblastoma is the most common intraocular tumor in children. The diagnosis is usually established by the ophthalmologist on the basis of fundoscopy and US. Together with US, high-resolution MRI has emerged as an important imaging modality for pretreatment assessment, i.e. for diagnostic confirmation, detection of local tumor extent, detection of associated developmental malformation of the brain and detection of associated intracranial primitive neuroectodermal tumor (trilateral retinoblastoma). Minimum requirements for pretreatment diagnostic evaluation of retinoblastoma or mimicking lesions are presented, based on consensus among members of the European Retinoblastoma Imaging Collaboration (ERIC). The most appropriate techniques for imaging in a child with leukocoria are reviewed. CT is no longer recommended. Implementation of a standardized MRI protocol for retinoblastoma in clinical practice may benefit children worldwide, especially those with hereditary retinoblastoma, since a decreased use of CT reduces the exposure to ionizing radiation.