ABSTRACT
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.
Subject(s)
Magnetic Resonance Imaging/instrumentation , Retinal Neoplasms/diagnosis , Retinoblastoma/diagnosis , Child , Child, Preschool , Female , Humans , Infant , Male , Prospective Studies , Retinal Neoplasms/pathology , Retinoblastoma/pathologyABSTRACT
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.
