Middle Ear Cholesteatoma: Non–Echo-planar Diffusion-weighted MR Imaging versus Delayed Gadolinium-enhanced T1-weighted MR Imaging—Value in Detection

Abstract

Purpose:To retrospectively compare non-echo-planar (non-EP) diffusion-weighted (DW) imaging, delayed gadoliniumenhanced T1-weighted magnetic resonance (MR) imaging, and the combination of both techniques in the evaluation of patients with cholesteatoma. Materials and Methods:This institutional review board-approved study, for which the need to obtain informed consent was waived, included 57 patients clinically suspected of having a middle ear cholesteatoma without a history of surgery and 63 patients imaged before "second-look" surgery. Four blinded radiologists evaluated three sets of MR images: a set of delayed gadolinium-enhanced T1-weighted images, a set of non-EP DW images, and a set of both kinds of images. Overall sensitivity, specifi city, negative predictive value (NPV), and positive predictive value (PPV), as well as intra-and interobserver agreement, were assessed and compared among methods. To correct for the correlation between different readings, a generalized estimating equations logistic regression model was fi tted. Results were compared with surgical results, which were regarded as the standard of reference. Results:Sensitivity, specifi city, NPV, and PPV were signifi cantly different between the three methods ( P , .005). Sensitivity and specifi city, respectively, were 56.7% and 67.6% with the delayed gadolinium-enhanced T1-weighted images and 82.6% and 87.2% with the non-EP DW images. Sensitivity for the combination of both kinds of images was 84.2%, while specifi city was 88.2%. The overall PPV was 88.0% for delayed gadolinium-enhanced T1-weighted images, 96.0% for non-EP DW images, and 96.3%for the combination of both kinds of images. The overall NPV was 27.0% for delayed gadolinium-enhanced T1-weighted images, 56.5% for non-EP DW images, and 59.6% for the combination of both kinds of images. Conclusion:MR imaging for detection of middle ear cholesteatoma can be performed by using non-EP DW imaging sequences alone. Use of the non-EP DW imaging sequence combined with a delayed gadolinium-enhanced T1-weighted sequence yielded no signifi cant increases in sensitivity, specifi city, NPV, or PPV over the use of the non-EP DW imaging sequence alone.q RSNA, 2010 Supplemental material: http://radiology.rsna.org/lookup /suppl

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

“…Delayed phase gadolinium enhanced T1 W imaging can be used for the diagnosis of cholesteatoma; however there are conflicting data about this method in the literature. Although some authors suggested that delayed phase post-contrast imaging is useful, others indicated that delayed phase post-contrast imaging could not provide additive information [9,16]. These conflicting results were believed to be related with the dimension of cholesteatoma [16].…”

“…Geometric distortion may lead to false negative or positive results by preventing the optimal evaluation of middle ear cavity and those artefacts are more prominent at 3 tesla (T) devices [2,8]. New techniques have been developed to avoid these artefacts including multi-shot echo-planar imaging (EPI), non-EPI or periodically rotated overlapping parallel lines with enhancedreconstruction (PROPELLER) techniques [2,7,9,10].…”

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

“…The reason for the high signal intensity is assumed to be a T2 shine-through effect or the restricted molecular diffusion of cholesteatoma. SS EPI-DWI frequently leads to artifacts, which could mask areas of restricted diffusion in a cholesteatoma and therefore SS EPI-DWI is no longer recommended [60,61]. The presently used non-EPI DWI method combines a sensitivity of 91.4 % and a positive predictive value of 97.3 % with a negative predictive value of 85 % [62].…”

“…Non-EPI DWI thus can prevent unnecessary revision surgery in patients who are suspected of having recurrent or residual disease as CT cannot discriminate cholesteatoma within a soft-tissue mass or partially filled with nonspecific imaging abnormalities [62]. DWI may also replace delayed gadolinium-enhanced T1w sequences [60]. 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].…”

“…The advantages of suppressing the signal from fat is to suppress artifacts due to high fat signals, to improve T2 contrast between fatty and non-fatty tissue, to enable detection of enhancing tumors hidden in fatty tissue, and the proof of adipose tissue, such as in lipoma, or cholesterol granuloma. Reading T1w and T2w basic sequences and T2w fat sat images is important because the very high STIR/TIRM ▶ Table 1 (Continuation) MRI sequences main pathologies/field of application diagnostic clues paraganglioma high peak enhancement, SER, and short TME on DCE [37] schwannoma low peak enhancement and SER with a longer TME on DCE [37] diffusionweighted imaging primary tumors low ADC values (lymphoma, followed by carcinoma, benign tumor and cystic lesions) [47] lymph node staging low ADC values [49] residual cancer after chemoradiation therapy lower increase in the percentage change of the mean ADC or decrease in ADC during treatment [51,52] cholesteatoma high signal on DWI [60] Granulation tissue, fibrous tissue, cholesterol granuloma or serous fluid…”