Diffusion-weighted MR Imaging Sequence in the Detection of Postoperative Recurrent Cholesteatoma

Abstract

Diffusion-weighted fast SE imaging enables the depiction of recurrent cholesteatoma in patients who have undergone middle ear surgery.

Aplicação da ressonância magnética no acompanhamento da cirurgia do colesteatoma

“…This image was not seen in the coronal view, thus supporting the idea that it was indeed an artifact. These two false positive cases of are in agreement with the findings in Dubrulle et al 15 in which a diffusion imaging hypersignal false positive was produced from bone powder used to fill up a labyrinthine fistula. Our study and other papers in the literature indicate that magnetic resonance imaging may be useful in the differentiation of granulation tissue and relapsing cholesteatoma.…”

“…Other studies using diffusion MRI reported high specificity levels in diagnosing cholesteatomas larger than 0.5cm (Table 1) 11,12,15,16 . Vercruysse 16 reported lower sensitivity levels due to increased prevalence of residual cholesteatomas smaller than 0.5cm in size.…”

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

“…TSE-based DWI is a spin-echo-based SS or multi-shot (MS) technique with longer echo time and a higher signal-to-noise ratio than SS EPI-DWI. However, these sequences don't show the susceptibility artifacts that are observed with standard EPI-DWI and better spatial resolution in the middle ear is possible [22]. Furthermore, thinner slices can be obtained than with EPI sequences.…”

“…high-resolution dark signal of cranial nerves and very high signal of liquor in SSFP [20] labyrinthitis lower signal intensity than liquor on SSFP [22] menière's disease endolymphatic hydrops as ratio of high post-gadolinium 3D-FLAIR signal intensity in the perilymphatic space and the high signal in MRI cisternographic sequences in both endolymph and perilymph: vestibule (mild: 34 -50 %, significant: > 50) cochlea (mild: extrusion of the scala media, significant: scala media larger than scala vestibuli) [25] 3D-TOF, TWIST/ TRICKS angiography, DCE vascular contact syndromes point, longitudinal and loop compression as well as indentation of cranial nerves on 3D-TOF [26] infantile hemangioma arterial enhancement on TWIST with gadofosveset trisodium [30] venous malformation venous enhancement on TWIST with gadofosveset trisodium [30] lymphatic malformation no enhancement on TWIST with gadofosveset trisodium [30] arteriovenous malformation arterial and venous enhancement on TWIST with gadofosveset trisodium [30] hypoxia low K trans [32] bone do not cause severe artifacts (as typically seen in computed tomography CT), which makes MRI a superior image modality for delineating tumors in the oropharynx and oral cavity [5]. The ability to discriminate fluid and mucus from soft tissue is extremely helpful in the imaging of sinonasal tumors.…”

“…It allows for the accurate detection of small masses such as schwannomas in the cerebellopontine angles and internal auditory canals, and detailed evaluation of the labyrinth of the inner ear [20,21]. In addition to a high signal in T1wC+, labyrinthitis may show a lower signal than fluid on SSFP [22]. 3 D imaging can be further obtained using special fast spin echo techniques, such as sampling perfection with applicationoptimized contrasts using different flip angle evolutions (SPACE) or volumetric isotropic turbo spin echo acquisition (VISTA).…”