MR-based follow-up after brachytherapy and proton beam therapy in uveal melanoma.

PURPOSE: MRI is increasingly used in the diagnosis and therapy planning of uveal melanoma (UM). In this prospective cohort study, we assessed the radiological characteristics, in terms of anatomical and functional imaging, of UM after ruthenium-106 plaque brachytherapy or proton beam therapy (PBT) and compared them to conventional ultrasound. METHODS: Twenty-six UM patients were evaluated before and 3, 6 and 12 months after brachytherapy (n = 13) or PBT (n = 13). Tumour prominences were compared between ultrasound and MRI. On diffusion-weighted imaging, the apparent diffusion value (ADC), and on perfusion-weighted imaging (PWI), the time-intensity curves (TIC), relative peak intensity and outflow percentages were determined. Values were compared between treatments and with baseline. RESULTS: Pre-treatment prominences were comparable between MRI and ultrasound (mean absolute difference 0.51 mm, p = 0.46), but larger differences were observed post-treatment (e.g. 3 months: 0.9 mm (p = 0.02)). Pre-treatment PWI metrics were comparable between treatment groups. After treatment, brachytherapy patients showed favourable changes on PWI (e.g. 67% outflow reduction at 3 months, p < 0.01). After PBT, significant perfusion changes were observed at a later timepoint (e.g. 38% outflow reduction at 6 months, p = 0.01). No consistent ADC changes were observed after either treatment, e.g. a 0.11 × 10-3mm2/s increase 12 months after treatment (p = 0.15). CONCLUSION: MR-based follow-up is valuable for PBT-treated patients as favourable perfusion changes, including a reduction in outflow, can be detected before a reduction in size is apparent on ultrasound. For brachytherapy, a follow-up MRI is of less value as already 3 months post-treatment a significant size reduction can be measured on ultrasound.

Prognostic Value of the Radiomics-Based Model in the Disease-Free Survival of Pretreatment Uveal Melanoma: An Initial Result.

OBJECTIVE: The aim of this study was to develop a pretreatment magnetic resonance imaging (MRI)-based radiomics model for disease-free survival (DFS) prediction in patients with uveal melanoma (UM). METHODS: We randomly assigned 85 patients with UM into 2 cohorts: training (n = 60) and validation (n = 25). The radiomics model was built from significant features that were selected from the training cohort by applying a least absolute shrinkage and selection operator to pretreatment MRI scans. Least absolute shrinkage and selection operator regression and the Cox proportional hazard model were used to construct a radiomics score (rad-score). Patients were divided into a low- or a high-risk group based on the median of the rad-score. The Kaplan-Meier analysis was used to evaluate the association between the rad-score and DFS. A nomogram incorporating the rad-score and MRI features was plotted to individually estimate DFS. The model's discrimination power was assessed using the concordance index. RESULTS: The radiomics model with 15 optimal radiomics features based on MRI performed well in stratifying patients into the high- or a low-risk group of DFS in both the training and validation cohorts (log-rank test, P = 0.009 and P = 0.02, respectively). Age, basal diameter, and height were selected as significant clinical and MRI features. The nomogram showed good predictive performance with concordance indices of 0.741 (95% confidence interval, 0.637-0.845) and 0.912 (95% confidence interval, 0.847-0.977) in the training and validation cohorts, respectively. Calibration curves demonstrated good agreement. CONCLUSION: The developed clinical-radiomics model may be a powerful predictor of the DFS of patients with UM, thereby providing evidence for preoperative risk stratification.

A Comparison of 3 T and 7 T MRI for the Clinical Evaluation of Uveal Melanoma.

BACKGROUND: Magnetic resonance imaging (MRI) is increasingly being used in the diagnosis and treatment planning of uveal melanoma (UM), the most common primary intraocular tumor. Initially, 7 T MRI was primarily used, but more recently these techniques have been translated to 3 T, as it is more commonly available. PURPOSE: Compare the diagnostic performance of 3 T and 7 T MRI of UM. STUDY TYPE: Prospective. POPULATION: Twenty-seven UM patients (19% female). FIELD STRENGTH/SEQUENCE: 3 T: T1- and T2-weighted three-dimensional (3D) spin echo (SE) and multi-slice (MS) SE, 7 T: T1-weighted 3D gradient echo (GE), T2-weighted 3D SE and MS SE, 3 T and 7 T GE dynamic contrast-enhanced. T1 weighted images: acquired before and after Gadolinium (Gd) administration. ASSESSMENT: For all sequences, scan and diagnostic quality was quantified using a 5-point Likert scale. Signal intensities on T1 and T2 relative to choroid and eye muscle respectively were assessed as well as the tumor prominence. Finally, the perfusion time-intensity curves (TICs) were classified as plateau, progressive, or wash-out. STATISTICAL TESTS: Image quality scores were compared between both field strengths using Wilcoxon signed-rank and McNemar tests. Paired t-tests and Bland-Altman were used for comparing tumor prominences. P < 0.05 was considered statistically significant. RESULTS: Image quality was comparable between 3 T and 7 T, for 3DT1, 3DT2, 3DT1Gd (P = 0.86; P = 0.34; P = 0.78, respectively) and measuring tumor dimensions (P = 0.40). 2DT1 and 2DT2 image quality were rated better on 3 T compared to 7 T. Most UM had the same relative signal intensities at 3 T and 7 T on T1 (17/21) and T2 (13/17), and 16/18 diagnostic TICs received the same classification. Tumor prominence measurements were similar between field strengths (95% confidence interval: -0.37 mm to 0.03 mm, P = 0.097). DATA CONCLUSION: Diagnostic performance of the evaluated 3 T protocol proved to be as capable as 7 T, with the addition of 3 T being superior in assessing tumor growth into nearby anatomical structures compared to 7 T. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 3.

MR imaging characteristics of uveal melanoma with histopathological validation.

PURPOSE: To evaluate the magnetic resonance imaging (MRI) characteristics of uveal melanoma (UM), to compare them with fundoscopy and ultrasound (US), and to validate them with histopathology. METHODS: MR images from 42 UM were compared with US and fundoscopy, and on 14 enucleated cases with histopathology. RESULTS: A significant relationship between the signal intensity on T1 and pigmentation on histopathology was found (p=0.024). T1 hyperintense UM were always moderately or strongly pigmented on histopathology, while T1-hypointense UM were either pigmented or non-pigmented. Mean apparent diffusion coefficient (ADC) of the UM was 1.16 ± 0.26 × 10-3 mm2/s. Two-thirds of the UM had a wash-out and the remaining a plateau perfusion time-intensity curve (TIC). MRI was limited in evaluating the basal diameter of flat tumors. US tends to show larger tumor prominence (0.5mm larger, p=0.008) and largest basal diameter (1.4mm larger, p<0.001). MRI was good in diagnosing ciliary body involvement, extrascleral extension, and optic nerve invasion, but limited on identifying scleral invasion. An increase of tumor prominence was associated with lower ADC values (p=0.030) and favored a wash-out TIC (p=0.028). An increase of tumor ADC correlated with a plateau TIC (p=0.011). CONCLUSIONS: The anatomical and functional MRI characteristics of UM were comprehensively assessed. Knowing the MRI characteristics of UM is important in order to confirm the diagnosis and to differentiate UM from other intra-ocular lesions and because it has implications for treatment planning. MRI is a good technique to evaluate UM, being only limited in case of flat tumors or on identifying scleral invasion.

Stereotactic irradiation on linear accelerator - ultrasound versus MRI in choroidal melanoma volume calculation.

BACKGROUND: Stereotactic irradiation is one of the treatment modalities for intraocular uveal melanoma. The study's purpose was to describe the background of stereotactic one-day session radiosurgery, how the comparison in the difference between the tumor volume measured values from the magnetic resonance imaging (MRI) method and the ultrasound method was related to it, and which method was more precise to be used for tumor regression after irradiation. METHODS: The group of 147 patients with choroidal melanoma was treated by stereotactic irradiation on the linear accelerator with a single dose of 35.0 Gy. During the standard treatment process the uveal melanoma volumes, needed for dose calculation, were obtained using MRI from the individual stereotactic planning scheme and by ultrasound from the ultrasound device. All volumes were statistically compared using the paired t-test, and for the visualization purpose, the Bland-Altman plot was used. RESULTS: In the group of patients, it was 70 (47.6%) males and 77 (52.4%) females. The tumor volume median was from MRI equal to 0.44 cm3 and from ultrasound equal to 0.53 cm3. The difference between the ultrasound and the MRI volume measured values was statistically significant. However, the Bland-Altman plot clearly documents that the two methods are in agreement and can be used interchangeably. In most of the cases, the measured values of the ultrasound-calculated volume achieved slightly higher measured values. CONCLUSIONS: The calculation of the intraocular uveal tumor volume is a crucial part of the stereotactic irradiation treatment. The ultrasound volume measured values were in most of the cases higher than the measured values from the MRI. Although the methods are comparable and can be used interchangeably, we are recommending using the more precise MRI method not only during the treatment but also on later regular medical checks of tumor regression or progression.

Efficacy and tolerability of chemosaturation in patients with hepatic metastases from uveal melanoma.

BACKGROUND: Patients with hepatic metastatic uveal melanoma still have a poor outcome. PURPOSE: To evaluate overall survival (OS), progression-free survival (PFS), and response predictors in these patients treated with chemosaturation by percutaneous hepatic perfusion with melphalan (CS-PHP). MATERIAL AND METHODS: Between June 2015 and March 2020, a total of 29 patients (median age 69.7 years; age range 30-81 years; 60% women; median BMI 25.7 kg/m2; range 18.7-35.3kg/m2; 1-6 procedures per patient) were treated with 53 CS-PHPs. All patients received cross-sectional imaging for initial and follow-up examinations. Baseline tumor load, extrahepatic tumor load, tumor response, PFS, and OS were assessed. Non-parametric statistics were used. RESULTS: After the initial CS-PHP, a partial response was observed in 11 patients (41%), stable disease in 12 patients (44%) and progressive disease in 4 patients (15%); two patients died before the response was evaluated. After initial CS-PHP, median OS was 12.9 ± 7.4 months and median PFS was 7.1 ± 7.4 months. OS after one year was 50%. After the second CS-PHP, median PFS was 7.9 ± 5.7 months. Seven patients had a liver tumor burden >25%, associated with a significantly shorter OS (6.0 ± 2.4 vs. 14.1 ± 12.7 months; P = 0.008). At the time of first CS-PHP, 41% (12/29) of the patients had extrahepatic metastases that did not affect OS (11.1 ± 8.4 months vs. 12.9 ± 13.6 months; P = 0.66). CONCLUSION: CS-PHP is a safe and effective treatment for the hepatic metastatic uveal melanoma, especially for patients with a hepatic tumor burden <25%.

In-vivo imaging for assessing tumor growth in mouse models of ocular melanoma.

Uveal melanoma (UM) and conjunctival melanoma (CM) are ocular malignancies that give rise to life-threatening metastases. Although local disease can often be treated successfully, it is often associated with significant vision impairment and treatments are often not effective against metastatic disease. Novel treatment modalities that preserve vision may enable elimination of small tumors and may prevent subsequent metastatic spread. Very few mouse models of metastatic CM and UM are available for research and for development of novel therapies. One of the challenges is to follow tumor growth in-vivo and to determine the right size for treatment, mainly of the posterior, choroidal melanoma. Hence, the purpose of this study was to establish a simple, noninvasive imaging tool that will simplify visualization and tumor follow-up in mouse models of CM and UM. Tumors were induced by inoculation of murine B16LS9 cells into the sub-conjunctival or the choroidal space of a C57BL/6 mouse eye under a surgical microscope. Five to ten days following injection, tumor size was assessed by Phoenix MicronIV™ image-guided Optical Coherence Tomography (OCT) imaging, which included a real-time camera view and OCT scan of the conjunctiva and the retina. In addition, tumor size was evaluated by ultrasound and histopathological examination of eye sections. Tumor growth was observed 5-9 days following sub-conjunctival or sub-retinal injection of seven-thousand or seventy-thousand cells, respectively. A clear tumor mass was detected at these regions using the MicronIV™ imaging system camera and OCT scans. Histology of eye sections confirmed the presence of tumor tissue. OCT allowed an accurate measurement of tumor size in the UM model and a qualitative assessment of tumor size in the CM model. Moreover, OCT enabled assessing the success rate of the choroidal tumor induction and importantly, predicted final tumor size already on the day of cell inoculation. In conclusion, by using a simple, non-invasive imaging tool, we were able to follow intraocular tumor growth of both CM and UM, and to define, already at the time of cell inoculation, a grading scale to evaluate tumor size. This tool may be utilized for evaluation of new mouse models for CM and UM, as well as for testing new therapies for these diseases.

[Intraocular perivascular epithelioid cell tumor: report of two cases].

Two male patients presented with painless vision loss to blindness in one eye, and the radiography examinations revealed an intraocular mass suspicious for choroidal melanoma. They underwent enucleation. The histopathological and immunohistochemical findings were compatible with the diagnosis of intraocular perivascular epithelioid cell tumor. Because of its rarity, intraocular perivascular epithelioid cell tumor is easy to be confused with other intraocular tumors on histopathological and immunohistochemical examinations. (Chin J Ophthalmol, 2021, 57: 857-860).

Using a novel MR imaging sign to differentiate retinal pigment epithelium from uveal melanoma.

PURPOSE: Retinal pigment epithelium (RPE) adenoma is a rare intraocular benign tumor. It is almost always misdiagnosed as uveal melanoma (UM) resulting in inappropriate management. The purpose of this study was to investigate MRI features of the RPE adenoma that may help differentiate this entity from UM. METHODS: MRI was performed in eight patients with pathology-proven RPE adenoma, five of whom had dynamic contrast-enhanced (DCE) MRI. The time-intensity curves (TIC) of all DCE-MRI were evaluated, and the maximum contrast index (CImax) were calculated. RESULTS: All eight tumors showed well-defined margins. They were homogeneously hyperintense on T1WI and hypointense on T2WI compared to vitreous body. An oval mass was seen in five tumors, lentiform in two tumors, and placoid-shaped in one tumor. After contrast administration, mild enhancement was identified in five tumors and moderate enhancement in three tumors. In all five tumors, DCE-MRI exhibited a plateau-shaped TIC with a median CImax of 0.37. A "dark-linear sign" (defined as low signal intensity linear zone located between tumor and enhanced choroid on post contrast T1WI with fat-suppression) was noted in all eight patients with RPE adenoma. CONCLUSION: RPE adenoma and UM often have similar MR imaging findings. This study reports for the first time a "dark-linear sign" on post contrast T1WI with fat-suppression seen in RPE adenoma. This observation may be characteristic of RPE adenoma and may help separate this entity from UM.

Cartesian MR fingerprinting in the eye at 7T using compressed sensing and matrix completion-based reconstructions.

PURPOSE: To explore the feasibility of MR Fingerprinting (MRF) to rapidly quantify relaxation times in the human eye at 7T, and to provide a data acquisition and processing framework for future tissue characterization in eye tumor patients. METHODS: In this single-element receive coil MRF approach with Cartesian sampling, undersampling is used to shorten scan time and, therefore, to reduce the degree of motion artifacts. For reconstruction, approaches based on compressed sensing (CS) and matrix completion (MC) were used, while their effects on the quality of the MRF parameter maps were studied in simulations and experiments. Average relaxation times in the eye were measured in 6 healthy volunteers. One uveal melanoma patient was included to show the feasibility of MRF in a clinical context. RESULTS: Simulation results showed that an MC-based reconstruction enables large undersampling factors and also results in more accurate parameter maps compared with using CS. Experiments in 6 healthy volunteers used a reduction in scan time from 7:02 to 1:16 min, producing images without visible loss of detail in the parameter maps when using the MC-based reconstruction. Relaxation times from 6 healthy volunteers are in agreement with values obtained from fully sampled scans and values in literature, and parameter maps in a uveal melanoma patient show clear difference in relaxation times between tumor and healthy tissue. CONCLUSION: Cartesian-based MRF is feasible in the eye at 7T. High undersampling factors can be achieved by means of MC, significantly shortening scan time and increasing patient comfort, while also mitigating the risk of motion artifacts.

Radiologic and Histopathologic Correlation of Different Growth Patterns of Metastatic Uveal Melanoma to the Liver.

PURPOSE: The purpose of this study was to correlate magnetic resonance imaging (MRI) radiographic results with histopathologic growth patterns of metastatic uveal melanoma (UM) to the liver. DESIGN: Clinicopathologic correlation. PARTICIPANTS: Patients with metastatic UM to the liver. METHODS: A retrospective review of MRI images of patients with metastatic UM to the liver at a single institution between 2004 and 2016 was performed. The MRI growth patterns were classified as nodular or diffuse. The histopathologic findings of core liver biopsies of liver metastases identified by needle localization in a subset of these patients were reviewed. The core samples were evaluated by routine light microscopy, including immunohistochemical/immunofluorescent staining for CD31, CD105, and HMB45, and classified as exhibiting an infiltrative or nodular growth pattern. MAIN OUTCOME MEASURES: Magnetic resonance images and core biopsy findings. RESULTS: A total of 32 patients were identified with metastatic UM to the liver that was imaged by MRI, and 127 lesions were identified. A total of 46 lesions were classified by MRI as infiltrative and 81 as nodular. There were 9 needle-localized core biopsies that corresponded to MRI of metastatic lesions. Of these 9 lesions, 3 that were classified as infiltrative on MRI exhibited stage I infiltrative histologic growth patterns; of the remaining 6 that were classified as nodular by MRI, 5 histologically demonstrated stage II or stage III infiltrative growth patterns and 1 histologically demonstrated a nodular growth pattern. CONCLUSIONS: Magnetic resonance imaging of hepatic infiltrative growth patterns of metastatic UM corresponded to stage I histologic infiltrative growth in the sinusoidal spaces, whereas MRI nodular growth patterns corresponded to stage II/III histologic infiltrative growth that replaced the hepatic lobule or histologic nodular growth in the portal triad that effaced adjacent hepatic parenchyma.

Ocular ultrasound versus MRI in the detection of extrascleral extension in a patient with choroidal melanoma.

BACKGROUND: To describe the superiority of ocular ultrasound in the diagnostic management of extrascleral extension in choroidal melanoma. CASE PRESENTATION: We present a case of a 94-year-old male with choroidal melanoma of the right eye imaged with MRI and ocular ultrasound to aid in the detection of extrascleral extension. CONCLUSIONS: With advancement in technology and new imaging modalities emerging, it can become difficult to determine the best diagnostic approach for patients. We believe that ocular ultrasound remains the superior imaging modality in detection of extrascleral extension in choroidal melanoma.

[Comparative analysis on the significances of contrast-enhanced ultrasound and dynamic contrast-enhanced magnetic resonance imaging in uveal melanoma diagnosis].

Objective: To compare the significance of contrast-enhanced ultrasound (CEUS) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in the diagnosis of uveal melanoma. Methods: It was a retrospective case series study. Sixty-three cases (63 eyes) of uveal melanoma patients (confirmed by histopathology) who underwent CEUS and DCE-MRI examination at Beijing Tongren Hospital during January 2010 and May 2014 were collected, including 30 males and 33 females, with average age of 47 years (ranged from 27 to 69 years). The data and images of CEUS and DCE-MRI were analyzed and the findings were reviewed and compared to pathology results so as to evaluate the diagnosis coincidence rate of using CEUS, DCE-MRI and both (combined CEUS and DCE-MRI). Fisher's exact test method was used to explore the efficiency of diagnosing uveal melanoma with CEUS, DCE-MRI and the two combined. Results: Among the 63 cases of uveal melanoma, the coincidence rates of CEUS, DCE-MRI and combined diagnosis for uveal melanoma were 93.7% (59/63), 90.5% (57/63) and 100% (63/63) respectively. There was no significant difference between CEUS and DCE-MRI (P=0.663). Fifty-five cases showed fast wash in and fast wash out, and 8 cases showed fast wash in and slow wash out in time-intensity curve of CEUS. Fifty-four cases showed rapid increase and rapid decrease, and 7 cases showed rapid increase and slow decrease, and 2 cases showed sustain enhancement in signal intensity-time curve of DCE-MRI. Conclusions: CEUS is an effective method in diagnosis of uveal melanoma. CEUS and DCE-MRI are of similar value in the diagnosis of uveal melanoma, physicians may be able to acquire more diagnostic information when using the two methods in combination.(Chin J Ophthalmol, 2018, 54: 194-198).

Magnetic resonance safety and compatibility of tantalum markers used in proton beam therapy for intraocular tumors: A 7.0 Tesla study.

PURPOSE: Proton radiation therapy (PRT) is a standard treatment of uveal melanoma. PRT patients undergo implantation of ocular tantalum markers (OTMs) for treatment planning. Ultra-high-field MRI is a promising technique for 3D tumor visualization and PRT planning. This work examines MR safety and compatibility of OTMs at 7.0 Tesla. METHODS: MR safety assessment included deflection angle measurements (DAMs), electromagnetic field (EMF) simulations for specific absorption rate (SAR) estimation, and temperature simulations for examining radiofrequency heating using a bow-tie dipole antenna for transmission. MR compatibility was assessed by susceptibility artifacts in agarose, ex vivo pig eyes, and in an ex vivo tumor eye using gradient echo and fast spin-echo imaging. RESULTS: DAM (α < 1 °) demonstrated no risk attributed to magnetically induced OTM deflection. EMF simulations showed that an OTM can be approximated by a disk, demonstrated the need for averaging masses of mave = 0.01 g to accommodate the OTM, and provided SAR0.01g,maximum = 2.64 W/kg (Pin = 1W) in OTM presence. A transfer function was derived, enabling SAR0.01g estimation for individual patient scenarios without the OTM being integrated. Thermal simulations revealed minor OTM-related temperature increase (δT < 15 mK). Susceptibility artifact size (<8 mm) and location suggest no restrictions for MRI of the nervus opticus. CONCLUSION: OTMs are not a per se contraindication for MRI. Magn Reson Med 78:1533-1546, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

DIFFERENTIAL MACULAR FEATURES ON OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN EYES WITH CHOROIDAL NEVUS AND MELANOMA.

PURPOSE: To evaluate optical coherence tomography angiography (OCTA) characteristics of macular vascular details in eyes with choroidal nevus and melanoma, compared with unaffected contralateral eye. METHODS: Retrospective comparative analysis comprising 70 patients with choroidal nevus and 36 patients with choroidal melanoma examined with optical coherence tomography angiography. Measurements included central macular thickness (CMT), superficial (sFAZ) and deep (dFAZ) foveal avascular zone (FAZ) area, and superficial (sCVD) and deep (dCVD) capillary vascular density (CVD). RESULTS: In patients with nevus, CMT (affected vs. unaffected eye) was similar (267 vs. 265 µm, P = 0.67), whereas in patients with melanoma, CMT demonstrated greater thickness in affected eye (322 vs. 259 µm, P < 0.0001). In eyes with nevus, the FAZ (affected vs. unaffected eye) showed similar values in sFAZ (0.238 vs. 0.232 mm, P = 0.72) and dFAZ (0.284 vs. 0.271 mm, P = 0.48). In eyes with melanoma, similar values for sFAZ (0.249 vs. 0.260 mm, P = 0.73) were noted, whereas dFAZ was larger in the affected eye with macular melanoma (0.530 vs. 0.252 mm, P = 0.012) and similar in eyes with extramacular melanoma (0.300 vs. 0.285, P = 0.75). Regarding CVD (affected vs. unaffected eye), eyes with nevus showed similar sCVD (54 vs. 53.9%, P = 0.81) and dCVD (60 vs. 59.4%, P = 0.19). Reduced dCVD was found in four eyes with nevus, all with three or more risk factors for growth (P < 0.01). In eyes with melanoma, significant reduction was found in both sCVD (50.5 vs. 53.1%, P = 0.006) and dCVD (56.6% vs. 59.8%, P = 0.0003). Reduction in sCVD was related to presence of subretinal fluid (P = 0.03). Reduction in dCVD was found with subretinal fluid presence (P = 0.003) or absence (P = 0.03), with both macular (P < 0.001) and extramacular (P < 0.001) melanoma, and with increasing tumor thickness (P = 0.005). Reduced dCVD was found in 11% of eyes with nevus versus 58% of eyes with melanoma (Chi-square test: 26.31; P < 0.0001). CONCLUSION: Compared with contralateral eye, eyes with choroidal nevus demonstrate similar CMT, FAZ, and CVD. In contrast, eyes with melanoma show increased CMT, enlarged FAZ, and reduced CVD, particularly related to increasing tumor thickness. Optical coherence tomography angiography could be a useful tool in differentiating choroidal nevus from melanoma.

IMAGE QUALITY AND ARTIFACTS ON OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY: Comparison of Pathologic and Paired Fellow Eyes in 65 Patients With Unilateral Choroidal Melanoma Treated With Plaque Radiotherapy.

PURPOSE: To study image quality and artifacts seen on optical coherence tomography angiography (OCTA). METHODS: Sixty-five consecutive patients with unilateral posterior uveal melanoma treated with plaque radiotherapy had OCTA during follow-up. Optical coherence tomography angiography was performed on both the affected and fellow eye. Signal strength and frequency of image artifacts on en face images were compared between affected and fellow eyes. RESULTS: A total of 130 eyes in 65 patients were analyzed, the mean age at time of OCTA was 55 years (median: 56, range: 12-81 years), and 39 (39/65, 60%) were female. Majority of tumors were located in the choroid (62/65, 95%) and extramacular (55/65, 85%). The mean distance to the foveola was 4 mm (median: 3, range: 0-18 mm) and optic nerve was 4 mm (median: 4, range: 0-16 mm). Optical coherence tomography angiography was performed at a mean 46 months after plaque radiotherapy. Most patients had a history of radiation maculopathy or papillopathy in the treated eye at the time of OCTA (46/65, 71%). Overall, 95 eyes (95/130, 73%) had at least one significant artifact on OCTA. The most common major artifacts were loss of focus (71/130, 55%), broad (>5 pixels width and >4 lines) blink lines (48/130, 37%), motion artifact (34/130, 26%), specular dot (33/130, 25%), and edge duplication (10/130, 8%). Statistically, eyes treated with plaque radiotherapy (affected vs. fellow eye) were more likely to have at least one major OCTA artifact (92 vs. 54%, P < 0.001) and, specifically, loss of focus was more frequent (78 vs. 31%, P < 0.001). Multivariate analysis found decreased visual acuity significantly associated with higher incidence of broad blink lines (P = 0.0166) and loss of signal (P < 0.0001), whereas male sex was associated with increased loss of signal (P = 0.0015), and distance to the foveola was related to edge duplication (P = 0.0119). CONCLUSION: Image artifacts on OCTA are commonly encountered and appear to be more frequent in eyes with pathology and poor visual acuity. Recognition of these artifacts might help improve image interpretation and decision making.

Uveal melanoma: quantitative evaluation of diffusion-weighted MR imaging in the response assessment after proton-beam therapy, long-term follow-up.

PURPOSE: The purpose of this prospective study was to investigate the proton-beam-induced changes in apparent diffusion coefficient (ADC) values of ocular melanoma treated with proton-beam therapy (PBT) in patients undergoing long-term magnetic resonance imaging (MRI) follow-up and to assess whether variations in ADC constitute a reliable biomarker for predicting and detecting the response of ocular melanoma to PBT. METHODS: Seventeen patients with ocular melanoma treated with PBT were enrolled. All patients underwent conventional MRI and diffusion-weighted imaging (DWI) at baseline and 1, 3, 6, and 18 months after the beginning of therapy. Tumor volumes and ADC values of ocular lesions were measured at each examination. Tumor volumes and mean ADC measurements of the five examination series were compared; correlation of ADC values and tumor regression was estimated. RESULTS: Mean ADC values of ocular melanomas significantly increased already 1 month after therapy whereas tumor volume significantly decreased only 6 months after therapy. Pretreatment ADC value of ocular melanomas and early change in ADC value 1 month after therapy significantly correlated with tumor regression. CONCLUSIONS: In ocular melanoma treated with PBT, ADC variations precede volume changes. Both pretreatment ADC and early change in ADC value may predict treatment response, thus expanding the role of DWI from diagnostic to prognostic.

Clinical evaluation of ultra-high-field MRI for three-dimensional visualisation of tumour size in uveal melanoma patients, with direct relevance to treatment planning.

OBJECTIVES: To assess the tumour dimensions in uveal melanoma patients using 7-T ocular MRI and compare these values with conventional ultrasound imaging to provide improved information for treatment options. MATERIALS AND METHODS: Ten uveal melanoma patients were examined on a 7-T MRI system using a custom-built eye coil and dedicated 3D scan sequences to minimise eye-motion-induced image artefacts. The maximum tumour prominence was estimated from the three-dimensional images and compared with the standard clinical evaluation from 2D ultrasound images. RESULTS: The MRI protocols resulted in high-resolution motion-free images of the eye in which the tumour and surrounding tissues could clearly be discriminated. For eight of the ten patients the MR images showed a slightly different value of tumour prominence (average 1.0 mm difference) compared to the ultrasound measurements, which can be attributed to the oblique cuts through the tumour made by the ultrasound. For two of these patients the more accurate results from the MR images changed the treatment plan, with the smaller tumour dimensions making them eligible for eye-preserving therapy. CONCLUSION: High-field ocular MRI can yield a more accurate measurement of the tumour dimensions than conventional ultrasound, which can result in significant changes in the prescribed treatment.