Colesteatoma: Utilidade da sequência de difusão sem echo-planar

Abstract

Cholesteatomas are cystic lesions which may be either congenital or acquired, affecting the ears and presenting typical imaging patterns at computed tomography because of its expansile nature and tendency to erode bone. However, particularly in cases of lesion residue or recurrence after surgery, the distinction between cholesteatoma and inflammatory tissue based solely on computed tomography findings may be quite difficult, if not impossible. Magnetic resonance imaging might be very useful, particularly in such a context, since delayed postcontrast and diffusion-weighted images can demonstrate different imaging patterns in these two situations. Artifacts related to air-bone interface in the mastoid region may represent a relevant limitation to the utilization of echo-planar diffusion-weighted imaging. Non-echo-planar diffusion-weighted imaging represents an alternative to resolve this problem, once this method is less subject to this type of artifact, besides offering images with higher spatial resolution and thinner slice thickness, allowing the detection of small-sized cholesteatomas. © Colégio Brasileiro de Radiologia e Diagnóstico por Imagem.