Tumor Control Probability and Time-Dose Response Modeling for Stereotactic Radiosurgery of Uveal Melanoma.

INTRODUCTION: Uveal melanoma (UM), while a rare malignancy, stands as the most prevalent intraocular malignancy in adults. Controversies persist regarding the dose dependency of local control (LC) through radiotherapy. This study seeks to elucidate the significance of the prescription dose by employing time-dose response models for UM patients receiving photon-based stereotactic radiosurgery (SRS). MATERIALS AND METHODS: Inclusion criteria comprised UM patients treated between 2005 and 2019. All patients underwent single-fraction SRS. Datapoints were separated into three dose groups, with Kaplan-Meier analysis performed on each group, from which time-dose response models for LC were created at 2, 4, and 7 years using maximum-likelihood fitted logistic models. RESULTS: Outcomes from 594 patients with 594 UM were used to create time-dose response models. The prescribed doses and the number of patients were as follows: 17-19 Gy (24 patients), 20 Gy (122 patients), 21 Gy (442 patients), and 22 Gy (6 patients). Averaged over all patients and doses, LC rates at 2, 4, and 7 years were 94.4%, 88.2%, and 69.0%, respectively. Time-dose response models for LC demonstrated a dose-dependent effect, showing 2-year LC rates of more than 90% with 20 Gy and 95% with 22 Gy. For four years and a LC of 90%, a dose of approximately 21 Gy was required. After seven years, the 21 Gy prescription dose is predicted to maintain a LC above 70%, sharply declining to less than 60% LC with 19 Gy and less than 40% with 18 Gy. CONCLUSION: In contrast to prior findings, the time-dose response models for UM undergoing photon-based SRS emphasize the critical role of the prescription dose in achieving lasting LC. The dose selection must be carefully balanced against toxicity risks, considering tumor geometry and individual patient characteristics to tailor treatments accordingly.

Self-Shielding Gyroscopic Radiosurgery for Uveal Melanoma: A First Case Report.

Stereotactic radiosurgery (SRS) is a well-established treatment modality for the management of uveal melanoma, achieving high tumor control and eye retention rates. There are several SRS treatment platforms available, including the recently developed self-shielding gyroscopic radiosurgery (GRS) system. We report the first use of GRS in the treatment of uveal melanoma. We report the treatment of a 63-year-old female patient with a left-sided uveal melanoma. Akinesia of the ocular globe in the orbit was achieved by retrobulbar anesthesia. The treatment plan used six isocenters (three with the 10 mm and three with the 7.5 mm apertures) and 140 beams to cover 99.2% of the planning target volume (PTV) with 21 Gy at the 54% isodose line. Treatment was delivered in a single session with the GRS device. The total workflow time from retrobulbar anesthesia to completion of treatment was 122 minutes. The procedure was flawless, clinically well tolerated by the patient, and reliably performed in an outpatient setting, thus comparable to our published experience with robotic SRS. The evaluation of new radiosurgery treatment platforms is critical to maintaining quality standards and refining future treatments.

Severe Visual Impairment Following CAR T-Cell Therapy in Two Individuals with Malignant Optic Nerve Infiltration.

We report two patients who displayed evidence of localized ocular inflammation after CAR T-cell infusion. To manage the resulting severe visual impairment, systemic corticosteroids were administered to both patients. This treatment led to a reduction in local inflammation and restored vision in one of the patients.

Tumor lysis syndrome induced by tebentafusp.

Tebentafusp, a bispecific T-cell receptor fusion protein directed against gp100 and CD3, can improve survival in patients with metastatic uveal melanoma and was recently approved for the treatment of HLA-A*02:01-positive uveal melanoma patients. Since tebentafusp often induces cytokine-release syndrome, doses must be escalated and patients monitored as inpatients after the first infusions. The occurrence of tumor lysis syndrome, a potentially life-threatening condition, after administration of a single dose of tebentafusp, is reported here. With adequate therapy, including the application of rasburicase, the patient made a full recovery. It is important to raise awareness of the adverse event profile of this new therapeutic approach among healthcare professionals to promptly recognize and treat side effects.

Tebentafusp is a new treatment for a type of eye cancer called uveal melanoma. It helps the body's defense system fight against cancer cells and has shown promise in helping patients live longer. However, not all patients with uveal melanoma can use this treatment. Only those who have a specific gene marker called HLA-A*02:01-positive can benefit from it. Like any new treatment, tebentafusp may have some side effects. One of them is called cytokine-release syndrome, which can cause symptoms like rash, fever and flu-like feelings. Usually, this side effect is not serious and can be treated well. There was a rare but serious case where one patient had a bad reaction after getting only one dose of tebentafusp. This reaction is called tumor lysis syndrome, which happens when cancer cells break down quickly and release harmful substances into the blood. This can be life-threatening. Thankfully, the patient received the right treatment and got better. This information is shared here with doctors and patients, so they know about possible side effects and can use tebentafusp safely.

Local Recurrence in Choroidal Melanomas following Robotic-Assisted Radiosurgery (CyberKnife).

Introduction: Tumor recurrence in choroidal melanoma has been associated with decreased overall survival due to metastatic spreading. To detect risk factors of local recurrence and side effects, we analyzed tumor planning and treatment parameters in patients with recurrence of choroidal melanoma after treatment with robotic-assisted radiosurgery (CyberKnife). Methods: Six hundred ninety-four patients treated with CyberKnife between 2005 and 2019 were retrospectively reviewed. Age, gender, best-corrected visual acuity, tumor height, and diameter were recorded. Treatment planning and radiation doses were reviewed. Salvage therapy, overall survival, metastasis, and complications were recorded. Results: Seventy-four patients showed local recurrence. Local recurrence occurred after 42.1 months post CyberKnife treatment (mean; range: 5-100 months). Fourteen out of 74 patients (18.9%) died during follow-up. Recurrence treatment included enucleation in 51 patients (68.9%) and radiosurgery in 19 patients (25.7%). Treatment planning without contrast medium MRI, radiation dose of less than 21 Gy, and insufficient margin delineation were identified as risk factors incrementing local control. Discussion: Robotic-assisted radiosurgery (CyberKnife) is a suitable treatment option for large choroidal melanoma up to 12 mm. Patients with significantly better visual acuity received repeat CyberKnife treatment as salvage therapy and showed an eye retention rate of 81%.

Robotic CyberKnife Radiosurgery for the Treatment of Choroidal and Ciliary Body Melanoma.

PURPOSE: To present the results of robotic-assisted radiosurgery in choroidal and ciliary body melanomas treated at the Department of Ophthalmology of Ludwig-Maximilians-University and the European CyberKnife Center in Munich, Germany. DESIGN: Interventional case series METHODS: This retrospective study included 594 consecutive patients referred to our clinic for the treatment of choroidal and ciliary body melanomas with robotic radiosurgery (CyberKnife) from 2005 to 2019. Eye retention, local control and disease-specific survival rates were calculated as Kaplan-Meier and actuarial estimates. The impact of prescription dose, tumor size, and ciliary body involvement was assessed by likelihood ratio tests and Cox regression. RESULTS: Among all patients who were staged according to the TNM classification system (8th edition), 22.7% were I, 57.9% were II, 18.9% were III, and 0.5% were IV. Median apical tumor height and base diameter were 5.8 and 11.4 mm. The mean follow-up was 41.7 months. Local control after 3 and 5 years was 92.0% (95% CI = 88.2%-94.7%) and 84.3% (95% CI = 77.9%-89.0%), respectively, for 21 to 22 Gy and 86.9% (95% CI = 79.7%-91.7%) and 77.7% (95% CI = 68.5%-84.6%), respectively, when treated with 20 Gy or less. Eye retention was achieved in 89.9% and 81.0% after 3 and 5 years with 21 to 22 Gy and 85.9% and 80.0% for 20 Gy or less. Disease-specific survival rates were 93.1% (95% CI = 90.2%-95.2%) after 3 years, 89.8% (95% CI = 86.0%-92.6%) after 5 years, and 87.8% (95% CI = 82.8%-91.4%) after 7 years. CONCLUSIONS: This is the largest series of patients treated for choroidal and ciliary body melanomas with CyberKnife. Our results reflect an improvement in the outcome of CyberKnife therapy for patients with choroidal and ciliary body melanoma treated with single-session radiosurgery in the last decade.

Pars-plana-vitrectomy for endophthalmitis treatment and the role of standardized ultrasound.

PURPOSE: Endophthalmitis is a severe inflammation following surgery or endogenous spread of pathogens. Besides clinical signs and symptoms, standardized ultrasound might help to confirm the diagnosis. Thus, we analyzed 172 cases of endophthalmitis for pathogens, visual acuity (VA) and the predictive value of standardized ultrasound. METHODS: Retrospective analysis of patients treated with pars-plana-vitrectomy for endophthalmitis at the University Eye Hospital was performed. Sex, age, VA at presentation, first day after surgery, four weeks postoperatively, and at last follow-up, as well as pathogen culture, and presence of standardized ultrasound before vitrectomy were recorded. Mann-Whitney U and Chi-square tests were used for groupwise comparisons. RESULTS: A total of 172 patients (male = 47.7%) with a median age of 76 years (IQR 65-82 years) treated for endophthalmitis (exogenous = 85.5%) were included. Median follow-up time was 65 days (IQR 12-274 days). Visual acuity at presentation was 2.30 logMAR (IQR 2.70-2.30 logMAR); it increased to 1.00 logMAR (1.4-0.40 logMAR) at last follow-up. A total of 79 patients (45.9%) underwent standardized ultrasound before vitrectomy. Patients with positive ultrasound criteria had a significantly decreased VA at presentation (p = 0.034). Positive microbiological cultures for Streptococcus spp. and Enterococcus faecalis were associated with decreased VA (p = 0.028) at last follow-up. CONCLUSION: Standardized ultrasound is an easy and robust tool in the diagnosis of endophthalmitis. Positive criteria are significantly associated with decreased VA at presentation. The recovery of VA depends on pathogens and is significantly worse for certain species (Streptococcus spp., Enterococcus faecalis).

Robotic CyberKnife radiosurgery for small choroidal melanomas.

Plaque brachytherapy is the most common procedure for the treatment of small choroidal melanoma, especially in posteriorly located tumors. However, there is only little information on outcome after treatment with stereotactic radiosurgery, for example, CyberKnife radiosurgery. We reviewed patients with choroidal melanoma (maximum tumor height 4 mm) treated with CyberKnife radiosurgery. Demographic information, tumor dimension, complications, metastasis and overall survival during the whole follow-up were tracked and analyzed with a specific focus on local tumor control and potential risk factors. One hundred eighty-eight patients (102 female, 54.2%) with a median age of 63 years [interquartile range (IQR): 54-73 years] were analyzed over a median of 46 months (IQR: 24-62 months). Metastasis occurred in 14 patients (7.4%) in median of 18 months after treatment (IQR: 13-47 months) and survival was achieved in 178 patients (94.7%). Within the observation period, eye retention was observed in 166 patients (88.3%). Superior local control was achieved in patients who received a prescription dose of at least 21 Gy or more (91.6%; P = 0.04). Other potential risk factors incrementing local control were treatment planning with missing MRI in advance and too small target delineation during the planning process. Radiosurgery (CyberKnife) in a single, outpatient procedure is suitable for the treatment of small choroidal melanoma. We found local control rate after 3 years compared to the standard treatment with plaque brachytherapy. On the study side, 15 years of CyberKnife treatment allowed to identify risk factors that might increment local control and thus improve treatment regimens.

Robotic assisted CyberKnife radiosurgery for the treatment of iris melanoma.

Iris melanoma is a rare form of uveal melanoma with potential metastic spread. Treatment options include surgical resection, enucleation or irradiation. We analysed visual outcome, complication appearance and management in eight patients with iris melanoma following robotic-assisted CyberKnife treatment. Consecutive patients from the Department of Ophthalmology at University of Munich were included in the study if they had an iris melanoma that was treated with CyberKnife and had a minimum follow-up of 12 months. We evaluated tumor thickness, largest diameter, visual acuity and complications. 8 patients were included in this report. The median age was 74 years (range: 53-86 years). The median follow-up was 23 months (range 12-48 months). Tumor thickness decreased from 2.1 to 1.4 mm on average. Four out of eight patients showed stable or increased visual acuity compared to visual acuity at first visit. We did not find a correlation of applied radiation volume or radiation dose on visual outcome. Radiation keratopathy was the most common complication in five patients. No recurrences were noted. Robotic-assisted radiosurgery following CyberKnife is a promising non-invasive, single session treatment option for iris melanoma with comparable results regarding recurrence rate or complications to brachytherapy and proton beam therapy. All included patients showed good visual outcome.

Robotic assisted CyberKnife radiosurgery for the treatment of choroidal metastasis.

PURPOSE: Choroidal metastases occur in many patients with systemic cancer and limit quality of life due to visual deterioration or pain. The limited prognosis of these patients demand treatment approaches that aim at a quick response and easy application. We evaluated a robotic assisted radiosurgery device, the CyberKnife, in the treatment of choroidal metastasis. METHODS: Following retrobulbar anaesthesia, target volume was defined by an interdisciplinary team using gadolinium-contrast-enhanced MRI, computer tomography (CT) as well as all previously obtained clinical data. Radiation was delivered in a single fraction with a CyberKnife at a radiation dose of 21 Gy with a 70% isodose. We evaluated tumour height, reflectivity, visual acuity and side effects over the course of the follow-up. RESULTS: A total of four patients were included in this report. Mean follow-up time was 31 months, and all patients showed decreased tumour volume and signs of fibrosis during follow-up. One patient remained stable in terms of visual acuity, two patients lost visual acuity and one patient improved and had a functional visual acuity at last follow-up. One patient developed radiation retinopathy with subsequent neovascular glaucoma that needed further management. All other patients did not show any signs of radiation induced side effects. CONCLUSION: We report on the outcome of robotic CyberKnife radiosurgery in the treatment of uveal metastasis. We believe that single session, outpatient treatment delivery that can be facilitated with CyberKnife radiosurgery offer some benefits for this particularly sick group of patients.

Robotic-assisted radiosurgery for the treatment of vasoproliferative tumours.

PURPOSE: Vasoproliferative tumours (VPT) are a rare but benign entity that can lead to severe visual acuity deterioration. There is no standard of care, and depending on the degree of clinical features, including tumour size and dissemination, visual acuity and subretinal fluid, treatment options include observation, cryotherapy and brachytherapy. Particularly in larger tumours, brachytherapy has advantages over other options, although higher radiation doses and the need for surgical application are disadvantages of this otherwise effective treatment option. CyberKnife radiosurgery might represent an alternative therapeutic option as no surgical intervention is needed and radiation doses are lower. METHODS: All patients diagnosed with vasoproliferative tumors who were treated with CyberKnife radiosurgery with a minimum follow-up time of 12 months were included in this case series. We recorded visual acuity, number of lesions, central retinal thickness with optical coherence tomography (OCT) and reflectivity using A-scan standardizes echography every three months. RESULTS: A total of four patients with a median age of 34 years (range: 24 - 51) who were observed over an average of 26.5 months (range: 17 - 49 months) matched our inclusion criteria. We appreciated stabilization or increase in visual acuity in all four patients and a regression in tumour thickness with subsequent increase in internal reflectivity as a marker of increasing fibrosis. CONCLUSION: We observed good visual and functional outcome following CyberKnife therapy for VPT. We believe that further studies should be pursued to evaluate CyberKnife therapy for the treatment of VPT not treatable with cryo- or lasertherapy.

Screening for Predictive Parameters Requiring Psycho-Oncological Intervention via the National Comprehensive Cancer Network Distress Thermometer in the Follow-Up of Uveal Melanoma Patients.

AIM: To assess a profile of uveal melanoma patients at risk of requiring active psycho-oncological intervention by employing the National Comprehensive Cancer Network (NCCN) distress thermometer. METHODS: Multivariate correlation and multiple linear regression analysis of data collected retrospectively from 106 consecutive patients suffering from uveal melanoma. RESULTS: Distress levels correlated with practical (p = 0.01), emotional (p = 0.003) and physical problems (p = 0.001) as well as the total number of issues reported (p < 0.001; ANOVA, respectively). Emotional issues added up to 39% of influence on distress levels. Nervousness, worry and sadness as the most important emotional issues tested correlated significantly with anatomic stage, tumor T-category, metastatic status and time after primary diagnosis and were present more frequently in patients with higher distress levels (p < 0.001, p = 0.002, p = 0.004, respectively, Fisher's exact test). Pre-existing psycho-oncological support was more frequent in metastatic patients and patients with higher anatomic stage tumors (p = 0.008 and p = 0.003; Fisher's exact test). CONCLUSION: The distress thermometer proved to be useful for rapid assessment of patients requiring active intervention. A higher number of distress items recorded correlated with elevated distress levels. Emotional issues were responsible for the majority of problems. A typical patient profile at risk of developing distress requiring close attention of caregivers includes high anatomic stage, high T-category, presence of metastases and early follow-up. Correct diagnosis and interpretation of distress-levels should help improve the quality of life of uveal melanoma survivors. TRIAL REGISTRATION: Not applicable.

The national comprehensive cancer network distress thermometer as a screening tool for the evaluation of quality of life in uveal melanoma patients.

PURPOSE: To assess quality of life (QoL) status via the National Comprehensive Cancer Network (NCCN) distress thermometer as a psychooncological screening tool in uveal melanoma patients. METHODS: One hundred and six consecutive patients suffering from uveal melanoma completed the distress thermometer between 04/2018 and 12/2018. Practical, emotional, family concerned, spiritual, physical and overall distress levels, distribution of distress and subgroup analyses defining groups of potential high distress levels in need of intervention were assessed. Descriptive statistics, cross-tabulations, chi-square and Fisher's exact test as well as correlation coefficients (Spearman's rho) and receiver operating characteristic (ROC) were used for analysis. RESULTS: Patients with higher T-category had significantly more emotional problems and spiritual concerns (p = 0.046 and p = 0.023, respectively). Female patients accounted for higher rates of physical issues (p = 0.034). Lower best corrected visual acuity (BCVA) was correlated with higher distress levels (p = 0.037). Patients resulting in loss of BCVA of ≥3 lines reported higher distress levels (p = 0.029). A distress threshold of 5 on the basis of ROC analysis showed a corresponding sensitivity of 100% and specificity of 76%. CONCLUSION: The NCCN distress thermometer could be integrated well into our clinical routine and proved to be a rapid, yet sensible screening tool for emotional and physical distress in patients with uveal melanoma. Special attention should be paid to patients with higher T-category and patients resulting in lower levels of BCVA. As in patients with different tumour entities, the established distress threshold of ≥5 proposing intervention proved to be adequate for uveal melanoma patients.

Incidence of secondary glaucoma after treatment of uveal melanoma with robotic radiosurgery versus brachytherapy.

PURPOSE: Different modalities of radiation therapy nowadays allow for effective treatment of uveal melanoma combined with the advantage of eye preservation. However, this advantage can secondarily be impaired by radiation-related side effects. After local recurrence, secondary glaucoma (SG) has been described as second most frequent complication leading to need of enucleation. This study compares the incidence of SG after conventional Ruthenium (Ru)-106 brachytherapy (BT) versus CyberKnife robotic radiosurgery (RRS) which has been gaining importance lately as an efficient treatment option offering improved patient comfort. METHODS: Medical records of all patients diagnosed with uveal melanoma in the Eye Clinic of the Ludwig-Maximilians-University Munich between 2007 and 2013 were reviewed. A total of 268 eyes of 268 patients treated with Ru-106 BT or CyberKnife-RRS as monotherapy were entered in this retrospective cohort study. Incidence of SG was correlated with treatment modality and baseline tumour characteristics. RESULTS: Fifty-three patients (19.8%) developed SG. At 5 years, SG was significantly more frequent after RRS (46.7%) than BT (11.1%); however, tumour thickness (maximum apical height) as a marker of tumour progress was more pronounced in the RRS group. Subgroup analysis of 178 patients for tumours amenable to both BT and RRS (thickness ≤6 mm) revealed comparable results at 3 years (RRS: 13.8 versus BT: 11.2%), but a trend towards increased incidence after RRS beyond year three. However, this difference was not significant at 5 years (28.2% versus 11.2%, p = 0.138). Tumour thickness was significantly associated with incidence of SG. CONCLUSION: In tumours ≤6 mm thickness, RRS and BT seem to offer a comparable safety profile in terms of SG. Beyond year three, SG was tendentially, but not significantly more frequent after RRS. Increasing tumour thickness is associated with risk of SG.

Robotic radiosurgery for the treatment of medium and large uveal melanoma.

The aim of the study was to analyze the local efficacy and eye retention rate after frameless, image-guided robotic radiosurgery against uveal melanoma. A total of 217 patients, mostly with medium and large unilateral uveal melanomas (3% small, 62% medium, and 35% large) were treated. The median age was 64 years (range 21-95 years). All patients underwent a single-session procedure beginning with retrobulbar anesthesia, followed by MRI and computerized tomography scanning to generate the treatment plan. The tumor dose was 18-22 Gy (mean, 20.3 Gy) prescribed to the 70% isodose line. Follow-up occurred at 3, 6, 12, and 18 months and yearly thereafter with clinical, ultrasound, and MRI studies. The median follow-up time was 26.4 months. All patients were treated in the frameless setup within 3 h. The actuarial 3- and 5-year eye retention rates were 86.7 and 73%, respectively. Local control at 3 and 5 years was 87.4 and 70.8%, respectively. Serviceable vision was maintained in 30.9% of patients at last follow-up. Treatment-induced glaucoma developed in 33 patients at a median 20.8 months (range, 5.8-54.0 months). Other adverse effects were hemorrhage (26 patients) and macular edema (seven patients). Frameless, single-session, image-guided robotic radiosurgery is an effective and straightforward treatment option for patients with medium and large uveal melanoma that are otherwise difficult to treat.

Intravitreal ranibizumab versus isovolemic hemodilution in the treatment of macular edema secondary to central retinal vein occlusion: twelve-month results of a prospective, randomized, multicenter trial.

PURPOSE: This is a prospective, randomized, multicenter, investigator-initiated trial to evaluate the 12-month effectiveness of isovolemic hemodilution (IH) with prompt versus deferred intravitreal injections (IVI) of ranibizumab 0.5 mg for the treatment of macular edema secondary to early central retinal vein occlusion (CRVO). METHODS: Eyes with macular edema due to CRVO having occurred not more than 8 weeks previously received either monthly ranibizumab IVI in combination with IH (group I, n = 28) or IH alone (group II, n = 30). From month 2 to 12, the patients in both groups could be treated with monthly intravitreal ranibizumab. The main outcome variables were gain of visual acuity and the course of central retinal thickness as measured with optical coherence tomography. RESULTS: At 12 months, eyes in group I on average gained +28.1 (±19.3) letters compared to +25.2 (±20.9) letters in group II (p = 0.326). This result was achieved with significantly fewer injections in group II. Additionally, 30% of the eyes in group II did not need ranibizumab IVI during the 12 months of the trial. CONCLUSION: Ranibizumab IVI in addition to IH proved to be highly effective in increasing visual acuity and reducing macular edema secondary to CRVO. Initial IH in early CRVO may be a first treatment option in patients anxious about IVI.

Quality of life in the follow-up of uveal melanoma patients after CyberKnife treatment.

To assess quality of life in uveal melanoma patients within the first and second year after CyberKnife radiosurgery. Overall, 91 uveal melanoma patients were evaluated for quality of life through the Short-form (SF-12) Health Survey at baseline and at every follow-up visit over 2 years after CyberKnife radiosurgery. Statistical analysis was carried out using SF Health Outcomes Scoring Software and included subgroup analysis of patients developing secondary glaucoma and of patients maintaining a best corrected visual acuity (BCVA) of the treated eye of 0.5 log(MAR) or better. Analysis of variance, Greenhouse-Geisser correction, Student's t-test, and Fisher's exact test were used to determine statistical significance. Physical Functioning (PF) and Role Physical (RP) showed a significant decrease after CyberKnife radiosurgery, whereas Mental Health (MH) improved (P=0.007, P<0.0001 and P=0.023). MH and Social Functioning (SF) increased significantly (P=0.0003 and 0.026) in the no glaucoma group, MH being higher compared with glaucoma patients (P=0.02). PF and RP were significantly higher in patients with higher BCVA at the second follow-up (P=0.02). RP decreased in patients with BCVA<0.5 log(MAR) (P=0.013). Vitality (VT) increased significantly in patients whose BCVA could be preserved (P=0.031). Neither tumor localization nor size influenced the development of secondary glaucoma or change in BCVA. Although PF and RP decreased over time, MH improved continuously. Prevention of secondary glaucoma has a significant influence on both SF and MH, whereas preservation of BCVA affects VT. Emotional stability throughout follow-up contributes positively toward overall quality of life. CyberKnife radiosurgery may contribute to attenuation of emotional distress in uveal melanoma patients.

Retinoblastoma - MR appearance using a surface coil in comparison with histopathological results.

PURPOSE: The purpose of this work was to evaluate the characteristic appearance of untreated retinoblastoma on a large sample in comparison to the histological findings after therapeutical enucleation. MATERIALS AND METHODS: In a prospective clinical trial 46 children with retinoblastoma in 63 affected untreated eyes were examined under general anesthesia on MRI using a 1.5-T system. The examinations were performed with a special surface coil applying an examination protocol including fast T2- and T1-weighted spin echo sequences and additional fast T1-WI after intravenous injection of Gd-DTPA in different planes. The imaging results were compared to the histopathological findings in 29 patients with 30 affected eyes. RESULTS: Comparing MRI findings and histopathological results, optic nerve infiltration was detected with a sensitivity of 53.8% and a specificity of 82.3% on MRI, infiltration of the choroid with a sensitivity of 75.0% and a specificity of 100.0%, and the degree of tumor calcification with a sensitivity of 91.7% and a specificity of 88.9%. In this study the characteristic MR appearance of untreated retinoblastoma was evaluated. CONCLUSION: MRI was helpful in relevant aspects of pretherapeutical retinoblastoma staging, deficits remain regarding optic nerve infiltration.

Development and evaluation of phantom for verification of section thickness at thin-section MR imaging.

The purpose of this study was to construct and evaluate a phantom for measurement of magnetic resonance (MR) imaging sections with thicknesses of 0.3-0.6 mm. The phantom consisted of 304 0.1-mm-thick disks, each of which had a single notch filled with a diluted solution of gadopentetate dimeglumine. Qualitative and quantitative evaluations of T1-weighted images with section thicknesses of 0.3-0.6 mm were performed. A computer simulation was performed to evaluate the influence of different examination angles. At quantitative evaluation, the difference between nominal and measured section thicknesses ranged from 11% (nominal section thickness, 0.6 mm) to 18% (nominal section thickness, 0.4 mm). Computer simulations revealed that the phantom's positioning along the z-axis had a negligible influence at quantitative evaluation.