Diffusion-weighted magnetic resonance imaging of the temporal bone

Abstract

This paper summarizes the value of diffusion-weighted magnetic resonance imaging in the evaluation of temporal bone pathology. It highlights the use of different types of diffusion-weighted magnetic resonance imaging in the different types of cholesteatoma, prior to first stage surgery and prior to second look surgery. The value of diffusion-weighted magnetic resonance imaging in the evaluation of pathology of the apex of the petrous bone and the cerebellopontine angle is also discussed.

Detection of cholesteatoma: High-resolution DWI using RS-EPI and parallel imaging at 3 tesla

“…Thus, DWI images of middle ear cavity should be obtained in the axial plane. We think that performing T1 and T2 W images in addition to RS-EPI is necessary for accurate detection of localization & extension of the lesions and detection of other pathologic conditions of the ears and/or cranium (such as fistulas, masses or abscess) [14,17]. As we have experienced in our study, 3D isotropic (voxel sizes < 1 mm) acquisition of T1 W and T2 W sequences might be useful for evaluation of whole cranium simultaneously.…”

“…These conflicting results were believed to be related with the dimension of cholesteatoma [16]. Delayed phase post-contrast T1 W imaging (45 minutes after intravenous gadolinium administration) has some disadvantages including increased cost, the scanning time and risk of nephrogenic systemic fibrosis [14,17]. In addition, some false positive results could be seen at delayed phase post-contrast T1 W imaging such as retained inflammatory secretions, which may simulate a nonenhancing cholesteatoma [18].…”

The Diagnostic Accuracy of Non-Echo-Planar Diffusion-Weighted Imaging in the Detection of Residual and/or Recurrent Cholesteatoma of the Temporal Bone

“…14,15,17 Because using increased DW signal intensity in non-EPI DWI sequences as a diagnostic criterion for cholesteatoma produces practically no false-positive results, non-EPI DWI is a very promising technique to be used in screening for residual and/or recurrent cholesteatoma. [14][15][16][17][18][19][20][21] Recent reports even discussed the use of a non-EPI DWI sequence as the only sequence in screening for pre-second-look residual and/or recurrent cholesteatomas. [14][15][16]19,20 In 2005, we introduced MR imaging with non-EPI DWI sequences for the detection of residual and/or recurrent cholesteatoma after primary cholesteatoma surgery.…”

MRI Sequences in Head & Neck Radiology – State of the Art

“…Images from non-EPI sequences or newer EPI techniques such as RESOLVE can even be fused with anatomical images (T1w and T2w) in coronal and/or axial orientation to better localize suspected lesions [63,64]. This also helps to differentiate e. g. the characteristic T1 hyperintensity of cholesterol granuloma, or asymmetric apex fat, and opacified/infected petrous apex [65].…”

“…Low signal on DWI [65] signal and T1wC+ contrast enhancement related to reactive inflammation may lead to overestimation of the size of the real tumor mass and potential overestimation of the T stage [12]. In T2w fat sat images, lymph node metastasis may show an enlarged size (minimum axial diameter of 8 -9 mm in level II and 7 -8 mm for the rest of the neck), loss of hilar structure and necrosis (varying level of low-to-high signal intensity depending on keratinization, and coagulation and liquefaction necrosis) [18].…”