Cochlear erosion due to a facial nerve schwannoma

Facial nerve schwannomas are rare benign neoplasms. We report a case of a 60-year-old woman who initially presented with vestibular complaints. Magnetic resonance imaging (MRI) revealed a facial nerve schwannoma centered on the right geniculate ganglion extending in the labyrinthine segment. The patient consulted again after 2 months because she developed a sudden and severe right-sided sensorineural hearing loss. MRI showed no progression or pathological enhancement in the membranous labyrinth. A cone beam computed tomography (CT) of the temporal bone was performed and revealed a large erosion at the region of the geniculate ganglion in open communication with the middle turn of the cochlea. This case report demonstrates the importance of CT in facial nerve schwannomas for evaluating the impact on the surrounding structures

The value of Magnetic Resonance Imaging in the preoperative evaluation and the postoperative follow-up of middle ear cholesteatoma

The purpose of this thesis was to evaluate the role of MR imaging, especially DW MR imaging in the preoperative evaluation of cholesteatoma patients and the postoperative follow-up of cholesteatoma patients. Regarding the use of DW MR imaging, difference should be made between EP DW sequences and non-EP DW sequences. In a first study phase, the combination of EP DW sequences and standard MR sequences -that is T2- and T1-weighted sequences- has been evaluated. T1-weighted imaging included sequences before and immediately after intravenous administration of gadolinium. Three subgroups of patients have been evaluated using this combined protocol. In a first subgroup, the result of this protocol in 55 patients suspected of having an acquired cholesteatoma showed a sensitivity, specificity, PPV and NPV of 81%, 100%, 100% and 40% respectively. No FP were reported which means that any hyperintensity on EP DW images can be diagnosed as cholesteatoma provided that the curvilinear air-bone interface artefacts are not misinterpreted as cholesteatoma. The low NPV can be explained by the presence of 9 FN cases caused by atelectatic retraction pockets or partially or completely evacuated cholesteatoma pockets. It was already known from the literature that the hyperintensity on DW sequences is caused by the retained keratine in the retraction pocket and that empty retraction pockets can cause FN findings. It should however be noted that 2 cholesteatoma out of the FN cases were detected by additional evaluation of standard MR sequences. In a second subgroup of 45 patients evaluated prior to their second-look surgery looking for residual cholesteatoma only 1 out of 7 residual cholesteatoma could be detected using this protocol resulting a very low sensitivity of 12.5%. Specificity, PPV and NPV were 100, 100 and 84%. All missed cholesteatoma had a size inferior to 5 mm. In a third subgroup, this combined protocol was tested in 23 patients following PBOT prior to their second-look surgery. Signal intensities in the obliterated cavities were mixed and confusing. More than half of the patients had a partial or complete opacification of the middle ear on CT scan. Two cholesteatoma were detected at surgery and had a size of 2 and 4 mm. Both cholesteatoma remained undetected on EP DW images but one of them could be diagnosed on standard MR sequences. The conclusion of this first study phase is that the combination of standard MR sequences before and after intravenous administration of gadolinium and EP DW sequences appears to have the highest sensitivity in detecting middle ear cholesteatoma and the size limit for detection of cholesteatoma using EP DW sequences is 5 mm. This makes EP DW sequences useless for the evaluation of the usually very small pre-second-look residual cholesteatoma in patients after CWU tympanoplasty and after PBOT. EP DW sequences can be used to evaluate patients prior to first-stage surgery taking into account that lesions smaller than 5 mm will be missed and that empty or evacuated retraction pockets display no high signal on DW sequences.These conclusions have been confirmed in several other papers in peer-reviewed journals. In the second study phase, the combined protocol was changed. The standard sequences have been adjusted to delayed gadolinium-enhanced T1-weighted imaging, based upon the work of Marc Williams and Denis Ayache. This means that imaging is performed 45 minutes after the intravenous administration of gadolinium. Immediate scanning after intravenous administration of gadolinium might result in FP findings as scar tissue and granulation tissue take time to enhance. The DW sequence has been changed from an EP DW sequence to a non-EP based DW sequence. The sequence we use is a single-shot turbo SE DW MR imaging sequence or half-Fourier acquisition single-shot turbo SE (HASTE) DW MR imaging sequence.This sequence has a thinner slice thickness, a higher resolution and a complete lack of air-bone interface artefacts in the temporal bone resulting in a possible capability of detecting smaller cholesteatoma.In the second study phase, this combined protocol has again been evaluated in the 3 same subgroups as in the first study phase. In a first subgroup of 21 patients, clinically and/or otoscopically suspected of having a middle ear cholesteatoma, the combined protocol detected 19 cholesteatoma. It should be stressed that these 19 cholesteatoma were all visualized and detected by both readers on the single-shot turbo SE DW sequence and that at least 6 lesions had a size below 5 mm. The 2 FN cases could be explained by an evacuated retraction pocket in one case and by motion artefacts in another case. In a second subgroup, the protocol was applied to 32 consecutive patients in a blinded and prospective study in order to detect residual cholesteatoma prior to second-look surgery resulting in a sensitivity, specificity, PPV and NPV of 90%, 100%, 100% and 96% respectively. One FN case was caused by motion artefacts. Excluding this FN case, sensitivity, specificity, PPV and NPV even reaches 100%.This made us conclude that MR imaging, using non-EP DW sequences is able to select patients for second-look surgery. In a third subgroup, the protocol was evaluated in 51 patients after PBOT detecting 3 cholesteatoma of which one was an incidentally discovered petrous apex congenital cholesteatoma. Again, signal intensities on standard sequences were mixed and confusing in the obliterated cavity. Non-EP DW sequences were able to detect all 3 cholesteatoma. In the third study phase the non-EP DW sequence alone, delayed gadolinium-enhanced T1-weighted MR sequences alone and the combination of both techniques were compared in the evaluation of cholesteatoma in 120 patients in a retrospective way.Fifty-seven patients clinically suspected of having an acquired cholesteatoma and 63 patients prior to second-look surgery were included. In the last subgroup of patients, 21 patients were evaluated looking for residual cholesteatoma and 42 patients were scanned looking for recurrent cholesteatoma. Evaluation was done by 4 readers, of which 2 experienced head and neck radiologist, 1 resident and 1 general radiologist. Surgery was regarded as gold standard.It was concluded that there was no statistical significant difference between the non-EP DW sequence alone and the combination of non-EP DW imaging sequence and delayed gadolinium-enhanced T1-weighted sequences. Also non-EP DW imaging sequences have significantly higher sensitivity, specificity, PPV, and NPV than delayed gadolinium-enhanced T1-weighted sequences, and results are less dependent on the observer s experience.MR imaging in patients suspected of having middle ear cholesteatoma can be applied by using only a non-EP DW imaging sequence, avoiding the need for further contrast agent administration. The imaging approach of middle ear cholesteatoma has changed significantly during the last decade.Whereas at the onset, CT scan was regarded as the only valid imaging tool for the evaluation of middle ear cholesteatoma, MRI has conquered its place in the evaluation of patients presenting with middle ear cholesteatoma. In patients prior to first-stage surgery presenting with a clinically evident cholesteatoma, CT scan has its place in the evaluation of ossicular erosion and tegmen integrity. It will also highlight temporal bone anatomy such as degree of aeration and position of facial nerve and possible dehiscence. However in patients with an unclear clinical history and a doubtful micro-otoscopy, MRI using non-EP DW sequences can be used as a screening tool to evaluate the presence of cholesteatoma. In those cases, MRI using non-EP DW sequences- should be preferred as the primary imaging tool.In case of an infected cholesteatoma or a cholesteatoma with clinical suspicion of associated complications MR imaging, using the combination of non-EP DW sequence and delayed gadolinium-enhanced T1-weighted sequences, is required in order to evaluate the middle ear, inner ear and middle fossa. In both last subgroups, CT scan is preserved for the immediate pre-operative setting to evaluate all anatomical details. The role of MR imaging and non-EP DW sequences more specifically has gained even more importance in the evaluation of patients prior to second-look evaluating the presence of residual cholesteatoma or in the evaluation of patients looking for recurrent cholesteatoma. It is clear that EP DW sequences have been abandoned and that non-EP DW sequences are to be preferred due to their higher imagingmatrix, thinner slices and completelack of susceptibility artefacts. There seems also to be growing evidence for the fact that the combination of non-EP DW sequences and delayed gadolinium-enhanced T1-weighted sequences are no longer required and that the evaluation of patients prior to second-look surgery can be performed using non-EP DW sequences as a screening tool. Association to T2-weighted sequences will enhance the possibility of locating any detected cholesteatomas.ADC maps also seem to have an advantage in differentiating cholesteatoma from post-operative tissue, scar tissue, inflammation and/or cholesterol granuloma as cholesteatoma is the only entity with a clear signal drop on ADC maps. As an alternative, an unenhanced T1-weighed sequence can be performed in order to demonstrate spontaneously hyperintense lesions such as cholesterol granuloma or cystic lesions with high protein content. Both lesions might give rise to a moderately intense signal on b1000 images. Cholesteatoma will not demonstrate a high signal on unenhanced T1-weighted sequence enabling differential diagnosis with both entities. CT can no longer be used as the primary imaging tool of patients in a pre-second look setting. Moreover, second-look surgery should preferably be replaced by MRI using non-EP DW sequences. CT scan should be reserved for the immediate pre-operative evaluation of these patients and selection of second-look should be performed based upon MRI using non-EP DW sequences.By doing so, the number of unnecessary second-look interventions can be reduced as well as the high number of useless CT scans prior to second-look surgery, thus reducing patients irradiation significantly.nrpages: 178status: publishe

Imaging anatomy of the jaw and dentition with cone beam computed tomography

Knowledge of dental, maxillary, and mandibular anatomy and the use of correct nomenclature is critical in the evaluation of a mandibulofacial and/or maxillofacial imaging data set. The use of the correct diagnostic imaging tool tailored to the patient's needs is of equal importance. This article highlights imaging anatomy and cross-sectional imaging modalities mainly focusing on cone beam computed tomography of the mandibulofacial and maxillofacial region

Labyrinthine enhancement on 3D black blood MR images of the brain as an imaging biomarker for cisplatin ototoxicity in (lung) cancer patients

Purpose Cancer patients treated with platinum-based chemotherapy can present with ototoxicity symptoms. The purpose of this work is to report the imaging features related to cisplatin ototoxicity. Methods Between December 2015 and March 2019, a cohort of 96 consecutive patients with lung cancer was selected. Only patients who received cisplatin chemotherapy and underwent an imaging protocol consisting of a Gd-enhanced 3D-BB and 3D-T1W sequence, as well as T2W sequence to exclude metastases, were included. Labyrinthine enhancement was assessed, and all findings regarding the auditory and vestibular function were retrieved from the clinical files. Results Twenty-one patients met the inclusion criteria. The Gd-enhanced 3D-BB images were used to divide them into the labyrinth enhancement group (LEG) and the labyrinth non-enhancement group (LNEG). None of these patients demonstrated enhancing regions on the 3D-T1W images. The labyrinthine fluid remained high on the T2 images in all patients, excluding metastases. The LEG consisted of 6 patients. The cochlea and semicircular canals were the most frequently affected regions. All the LEG patients that presented with hearing loss (4/6) had cochlear enhancement. Patients with normal hearing had no cochlear enhancement. Five patients (5/6) showed vestibular enhancement. Four of these patients had vestibular symptoms. Conclusion Labyrinthine enhancement as an imaging feature related to cisplatin ototoxicity is unreported. This study demonstrates a correlation between hearing loss and cochlear enhancement and also between vestibular impairment and vestibular/semicircular enhancement on 3D-BB images, which remained invisible on the 3D-T1W images. The labyrinthine enhancement on 3D-BB images in the presence of normal signal intensity of the intralabyrinthine fluid can be used as an imaging biomarker for cisplatin toxicity in daily clinical practice and should not be mistaken for intralabyrinthine metastases

Results, hearing rehabilitation, and follow-up with magnetic resonance imaging after tympanomastoid exenteration, obliteration, and external canal overclosure for severe chronic otitis media

Objectives: We sought to evaluate the results, auditory rehabilitation, and follow-up with magnetic resonance imaging (MRI) after tympanomastoid exenteration with obliteration of the mastoid cavity and overclosure of the external ear canal in patients with severe chronic otitis media that was resistant to medical therapy and conventional surgery and was associated with a profound sensorineural or severe conductive hearing loss. Methods: Twenty-nine patients were analyzed and underwent this surgical technique. Twelve patients had, during the same or later stage, either cochlear implantation, fixture implantation for a bone-anchored hearing aid, or middle ear implantation. For follow-up control of the obliterated cavity, delayed gadolinium-enhanced, T1-weighted MRI in combination with non-echo planar imaging diffusion weighted sequences were used. Results: No patient had recurrent otorrhea after an average follow-up period of 4.75 years. One patient had a residual cholesteatoma as shown by new MRI techniques, and this was successfully resected. One patient developed complications 6 months after 1-stage tympanomastoid exenteration and cochlear implantation. Conclusions: This technique is very useful in selected patients with severe chronic otitis media that is resistant to medical therapy and surgery and is associated with a profound sensorineural or severe conductive hearing loss. New sequences in MRI are used for postoperative follow-up of these obliterated cavities and seem reliable for the detection of residual or recurrent cholesteatoma. Middle ear implantation and cochlear implantation can be relatively safely performed in these patients in a second stage. </jats:sec

Aberrant internal carotid artery presenting as a retrotympanic vascular mass

Abstract: We report a case of a young woman with an aberrant right internal carotid artery (ICA) presenting as a retrotympanic reddish mass. This variant of the ICA represents the collateral pathway that is formed as a result of an embryological agenesis of the cervical segment of the ICA. The embryonic inferior tympanic artery is recruited to bypass the absent carotid segment. This hypertrophied vessel may be seen otoscopically and wrongfully considered to be a vascular middle ear tumor. Informing the otorhinolaryngologist of this important vascular variant not only obviates biopsy but also helps in careful preoperative planning of eventual middle ear procedures