Conventional, diffusion, and permeability MR findings in ocular medulloepithelioma.

PURPOSE: To describe the neuroradiological features of intraocular medulloepithelioma. METHODS: We retrospectively analyzed the clinical, histopathological, and MRI data of five children with medulloepithelioma. In addition to conventional images, DWI was performed in four patients and mean ADC was calculated; this was limited to the technique of this cohort of patients. DCE was performed in all patients. This is the first paper that presents diffusion and perfusion characteristics of medulloepithelioma. RESULTS: Four tumors were malignant teratoid variants, two non-teratoid variants. Tumors were hyperintense on T1-weighted images and hypointense on T2-weighted images. Calcifications were detectable in two out of five tumors. Cavities were detectable in three out of five tumors. All tumors showed some degree of enhancement. The mean ADC of all four patients was 1.156 ± 242.75 × 10-3 mm2/s. Mean ktrans, Ve, Kep, TME, AUC, SER, and peak enhancement were 0.082 ± 0.054, 0.19 ± 0.076, 0.31 ± 0.084, 0.97 ± 0.0784, 1.22 ± 0.81, 67.34 ± 31.7, and 14.84 ± 7.34 respectively. TICs showed a very high ratio of slow increase, > 50% persistence and some degree of wash out. Teratoid variants showed higher K-trans, AUC, VE, TME, and persistent TIC pattern than non-teratoid ones, while plateau pattern ratio was lower. CONCLUSION: Conventional MR findings were similar to previously reported cases. Mean ADCs were moderately high. TICs showed slow increase and presence of wash out. K-trans, AUC, VE, and TME were higher in teratoid variants. Permeability parameters in differential diagnosis with lesions mimicking medulloepithelioma need further investigations.

Identification of Intraorbital Arteries in Pediatric Age by High Resolution Superselective Angiography.

PURPOSE: Angiography is a powerful tool to identify intraorbital arteries. However, the incidence by which these vessels can be identified is unknown. Our purpose was to determine such incidence and which angiographic approach is best for the identification of each artery. METHODS: A retrospective study of 353 angiographic procedures (via ophthalmic artery and/or external carotid artery) carried out on 79 children affected by intraocular retinoblastoma was made to investigate the arterial anatomy in 87 orbits. For each intraorbital artery two parameters were calculated: the angiographic incidence, as the percentage of times a given artery was identified, and the visibility index, as the ratio between the angiographic incidence and the true anatomic incidence. RESULTS: All collaterals of the ophthalmic artery could be spotted. Most of them were identified with a high angiographic incidence; some of them were less easily identified because too thin or because frequently shielded. The visibility index paralleled the angiographic incidence of most arteries. However, the lacrimal and meningolacrimal arteries had a higher visibility index suggesting that their identification was more frequent than the angiographic incidence alone could suggest. Statistical analysis demonstrated that the lacrimal artery and some muscular branches had higher chances to be identified if the angiography of the ophthalmic artery was accompanied by the study of the external carotid system. CONCLUSION: This work provides an objective measure of how powerful angiography is to identify intraorbital arteries as well as useful references for professionals who need to operate in the orbit.