Correction to: Magnetic resonance imaging features of the superior cervical ganglion and expected changes after radiation therapy to the head and neck in a long-term follow-up.

In the article "Magnetic resonance imaging features of the superior cervical ganglion and expected changes after radiation therapy to the head and neck in a long-term follow-up", one of the author names, K Chokkappan, was spelled incorrectly.

Magnetic resonance imaging features of the superior cervical ganglion and expected changes after radiation therapy to the head and neck in a long-term follow-up.

PURPOSE: This study aimed to assess the magnetic resonance (MRI) features of the superior cervical ganglion (SCG) and to track changes to it induced using radiotherapy across a long-term follow-up. METHODS: In total, 75 patients who underwent radiotherapy for head and neck malignancies and who were studied with MRI were recruited from two centers. MRI was performed before and after radiotherapy, with a median long-term follow-up of 4.5 years. Baseline SCG features were assessed. Changes in axial cross-sectional area, T2-normalized signal, and apparent diffusion coefficient (ADC) (the latter available in about half of the patients) were analyzed. Repeated measures analysis of variance with Bonferroni's correction was used to analyze changes in the aforementioned parameters (significance level 0.05). RESULTS: Out of a potential 149 SCGs, 136 were visible at baseline MRI. A variable spatial relationship with the internal carotid artery was found. SCGs showed the "black dot" sign in almost all of the patients. ADC was higher in SCGs than in regional lymph nodes. Cross-sectional area, normalized T2, and ADC increased in the period up to 1 year after radiotherapy and then remained stable in subsequent longer-term follow-up. CONCLUSION: The SCG has unusual features that allow differentiation from the regional lymph nodes. Changes in morphology and signal after radiotherapy must be taken into account by radiologists to avoid misdiagnosis as recurrent nodal disease. Changes induced using radiotherapy are stable in long-term follow-up and are thus likely attributed to other factors (such as Schwann cell hypertrophy/proliferation) rather than edema.

Atypical culture-negative skull base osteomyelitis masquerading as advanced nasopharyngeal carcinoma.

Skull base osteomyelitis typically arises as a complication of otogenic or sinonasal infections in immunocompromised patients. A much rarer entity, atypical skull base osteomyelitis is not associated with an obvious infective source. Atypical and culture-negative skull base osteomyelitis is even rarer and hampers diagnosis, as its clinical presentation is remarkably similar to skull base neoplasms. We report a case of extensive skull base osteomyelitis with orbital apex syndrome and multiple lower cranial nerve palsies which initially masqueraded as possible advanced nasopharyngeal carcinoma. Extensive investigations and consult with an infectious diseases specialist aided in elucidation of the correct diagnosis. Through this article, we emphasize that skull base osteomyelitis must be considered in the setting of headache, cranial neuropathies, elevated inflammatory markers and abnormal imaging findings. Early tissue sampling for histology, stainings and cultures and prompt appropriate treatment may prevent or arrest further complications.

Neuroendocrine adenoma of middle ear with new bone formation and review of literature.

Neuroendocrine adenoma of the middle ear has been described in literature as middle ear adenoma with neuroendocrine differentiation or carcinoid tumor. While there have been several case reports describing imaging features of carcinoid tumors of the ear and middle ear adenomas, in our literature review, we have not found a single case where bone formation is described as a prominent radiological feature. We report a first documented case of middle ear carcinoid tumor with new bone formation demonstrated on CT imaging and performed a review literature regarding the tumor. A differential diagnosis of neuroendocrine adenoma of the middle ear should be considered when there is prominent bone formation with a soft tissue mass in the middle ear on CT imaging.

Evaluation of cholesteatoma: our experience with DW Propeller imaging.

BACKGROUND: Cholesteatoma management includes early detection and surgical exploration. Due to its tendency to recur, it can be potentially locally aggressive. Magnetic resonance imaging (MRI), and in particular diffusion weighted imaging (DWI), plays an important role in management of these lesions. PURPOSE: To assess the accuracy of Propeller (Periodically Rotated Overlapping ParallEL Lines with Enhanced Reconstruction) DW sequence in detecting middle ear and mastoid cholesteatomas in non-operated ears by surgical correlation. MATERIAL AND METHODS: A retrospective review of 15 patients was done who underwent Propeller DWI with either clinically confirmed or suspected cholesteatomas. Surgical correlation was done in all cases. RESULTS: All patients had hyperintense foci on Propeller DWI. Surgical correlation performed revealed that 13 patients had cholesteatomas while two patients had mastoid abscesses. The location, extent, and size of cholesteatomas on Propeller DWI matched with the operative findings. Of the 13 patients with cholesteatomas, three patients had multiple foci of hyperintensity on Propeller DWI, which corroborated with the surgical finding of multiple cholesteatomas. The average apparent diffusion coefficient value of cholesteatoma was 0.868 × 10(-3) mm(2)/s, found to be higher than that of abscess, which was 0.425 × 10(-3) mm(2)/s. CONCLUSION: Propeller DWI was accurate in assessing the location, extent, and size of cholesteatomas as corroborated with surgical findings. Propeller DWI is useful in detecting number of cholesteatoma foci, a vital finding as it may impact the choice of surgery.

Pre-operative high resolution computed tomography scans for cholesteatoma: has anything changed?

OBJECTIVE: CT temporal bone scans are often performed to aid in surgical planning and management of cholesteatomas. With improvements in the resolution of CT scans today, it is now possible to obtain more information from these scans than before. The aim of this study is to compare findings on high resolution CT (HRCT) temporal bone scans to intra-operative findings, so as to determine how well various middle ear structures are assessed by HRCT scanning. STUDY DESIGN: Retrospective study. SETTING: Otology clinic of a tertiary otolaryngology centre. SUBJECTS AND METHODS: 32 mastoidectomies performed by a single otologist for clinically confirmed cholesteatoma were included. Correlation of CT and intra-operative findings on the status of structures including the ossicles, semicircular canals, facial canal and tegmen was analysed using kappa and AC1 statistics. RESULTS: In all patients, a soft tissue mass with bony erosion in keeping with a cholesteatoma was seen on CT. Radiosurgical agreement was excellent for the presence of semicircular canal erosion (k=0.89, AC1=0.96), facial canal dehiscence (k=0.74, AC1=0.76), tegmen erosion (k=0.76, AC1=0.92) and malleus erosion (k=0.76, AC1=0.85). It was good for incus erosion (k=0.71, AC1=0.92) and stapes erosion (k=0.63, AC1=0.73). CONCLUSION: There was good to excellent radiosurgical agreement in the assessment of the status of various middle ear structures. Improvement in radiosurgical agreement from existing studies in the literature was noted. This was especially true for features such as facial canal dehiscence. With technological advancements, CT temporal bone scans appear even more valuable for evaluation of patients prior to cholesteatoma surgery.

Mucous retention cyst of temporal bone: a mimic of cholesteatoma on DW-MRI.

Non-EPI DW imaging is increasingly being used as a sensitive sequence in detecting cholesteatomas especially if CT findings are not confirmatory. Cholesteatoma appears as a hyperintense focus on DWI. We present two cases of mucous retention cysts in the mastoid temporal bone/middle ear cavity, which present as hyperintense on non-EPI DWI and potentially may mimic cholesteatomas. Differentiating between the two conditions is important, as surgery can be avoided in mucous retention cysts. We have also discussed ways to differentiate between these two conditions on MRI. To our knowledge, this entity is not reported previously.

Finding nemo: imaging findings, pitfalls, and complications of ingested fish bones in the alimentary canal.

In Asian cuisine, fish is often prepared whole with the bones. Accidental fish bone (FB) ingestion is not an infrequently encountered condition in the emergency department. An impacted FB in the alimentary canal can lead to potentially life-threatening complications. For impacted FBs that cannot be visualized clinically, radiographs and multidetector computed tomography are helpful in localizing the FB, evaluating for complications, and planning treatment. In this pictorial essay, we illustrate the spectrum of radiological findings of impacted FBs, common imaging pitfalls, and complications. Finally, we highlight the imaging findings that are important to the clinician in planning treatment.

Bilateral enlarged vestibular aqueduct with associated bilateral Mondini's dysplasia.

Enlarged Vestibular Aqueduct (EVA) and Mondini's dysplasia (incomplete partitioning type II) are entitites that have been fairly well described in the literature as potential causes of hearing loss in the young. However, it is uncommon for this condition to be detected bilaterally, especially so for both conditions to coexist bilaterally in the same patient. This is a brief description of a patient with the above bilateral condition with attached high resolution CT scan images of the temporal bone to illustrate the case.

CT and MRI evaluation of nerve sheath tumors of the cervical vagus nerve.

OBJECTIVE: Nerve sheath tumors arising from the cervical vagus are rare. The purpose of this study was to evaluate the role of CT and MRI in the diagnosis of these uncommon neoplasms. MATERIALS AND METHODS: The CT and MR studies and clinical data of 11 patients with surgicopathologic evidence of a nerve sheath tumor of the cervical vagus (nine schwannomas [including two ancient schwannomas] and two neurofibromas) who had been referred to our institute from January 1999 through 2009 were retrospectively reviewed. The tumors were evaluated with respect to their location, number, morphology, attenuation and/or signal intensity, enhancement characteristics, and patterns of mass effect. RESULTS: The tumors were solitary and well circumscribed. On CT, eight tumors were hypodense with poor enhancement, two were predominantly isodense, and a single lesion had multiple cystic areas with enhancing solid components. On MRI, they were heterogeneously bright on T2-weighted images with intense, inhomogeneous postgadolinium enhancement. The "split fat" sign, "entering and exiting nerve" sign, "fascicular" sign, and "hyperintense rim" sign were seen in some patients. The internal or common carotid artery was displaced anteriorly in eight patients, maintained a neutral position in two patients, and was displaced posterolaterally in another patient. In all patients except two, the tumor separated the carotid artery from the internal jugular vein. Vagal schwannomas splayed the carotid bifurcation in three patients. CONCLUSION: In conclusion, we present the patterns of mass effect and a spectrum of CT and MRI characteristics of nerve sheath tumor of the cervical vagus including observations that are sparingly described in the published literature.

Concurrent chemoradiation in locally advanced primary middle ear lymphoepithelial carcinoma: an effective treatment modality case report.

BACKGROUND: Definitive treatment of primary middle ear lymphoepithelial carcinoma (LEC) is not well established owing to the rarity of this disease entity. We report a case of locally advanced primary middle ear LEC treated with concurrent chemoradiation, with good oncologic outcomes. CASE PRESENTATION: A 46 year-old female of Cantonese (Southern Chinese) descent presented with a four-month history of left sided hearing loss and non-pulsatile tinnitus, associated with progressive ipsilateral facial weakness. She had a left facial palsy (House-Brackmann 2) which then deteriorated to complete palsy over 2 weeks. Otoscopic examination of the left ear revealed a red-hued mass replacing the tympanic membrane. There was no cervical lymphadenopathy. Fibreoptic nasoendoscopy was unremarkable. Pure tone audiometry revealed profound mixed left hearing loss with type B impedance. Computed tomography of the temporal bone showed an ill-defined left middle ear mass with erosion of the malleus, tegmen tympani and facial canal. Magnetic Resonance Imaging showed an avidly enhancing lesion involving the dura of the left middle cranial fossa, tympanic and labyrinthine portions of the facial nerve. This mass extended into the apex of the left internal acoustic canal and basal turn of the cochlea. Histopathology confirmed EBV-positive primary middle ear LEC. Concurrent chemoradiation comprising 70Gy of intensity-modulated radiation therapy and 3 cycles of concurrent Cisplatin based chemotherapy over a 6 week period was administered. The patient achieved near-complete disease resolution on 3 month post-treatment imaging. Serum EBV DNA titres declined to undetectable levels and the patient is disease-free at 18 months post-diagnosis. DISCUSSION AND CONCLUSION: Concurrent chemoradiation with curative intent may be a viable treatment option for locally advanced middle ear LEC not amenable to surgical resection due to expected surgical morbidity. It confers good oncologic outcomes that mimic the response in other head and neck EBV-related lymphoepithelial carcinomas.

Transient global amnesia and focal diffusion weighted imaging lesions in mesiotemporal region: A ten-year experience.

OBJECTIVE: To determine prevalence and characteristics of mesiotemporal diffusion weighted imaging (DWI) lesions in transient global amnesia (TGA), and to determine prevalence of "missed" DWI lesions on routine radiological reporting. METHODS: This is a retrospective study of patients with TGA admitted to a tertiary care hospital over ten years. Patients with TGA, who underwent magnetic resonance imaging (MRI) of the brain within one week of index event, were included in this study. MRI's were reviewed by two independent raters. Clinical data and other investigations were collated. RESULTS: Of the 55 patients of TGA, 19 (35 %) had hyperintense DWI lesions with concordant apparent diffusion coefficient (ADC) hypointensity in the mesiotemporal region. Fifteen out of 19 (79 %) had unilateral lesions (6 left, 9 right). Twelve out of 19 DWI lesions were reported at the time of index scan. The false negative reporting rate was 36.8 %. DWI slice thickness (5 mm versus 3 mm), MRI machine strength (1.5 versus 3 T) and time interval from symptom onset to MRI brain (>24 h versus ≤ 24 h) were not significantly different between patients with or without DWI lesions and as well between patients with DWI lesions missed and initially reported at the time of index scan. CONCLUSION: Punctuate DWI mesiotemporal lesions in TGA are prone to under-reporting. These lesions need to be categorically searched for at the time of reporting MRI Brain.

Imaging Features Differentiating Vestibular Ganglion from Intracanalicular Schwannoma on Single-Sequence Non-Contrast Magnetic Resonance Imaging Study.

INTRODUCTION: This study aimed to identify imaging features on single-sequence noncontrast magnetic resonance imaging (MRI) that differentiate the vestibular ganglion from small intracanalicular schwannomas. MATERIALS AND METHODS: Ninety patients (42 men and 48 women; age: 24‒87 years old) with 102 internal auditory canal (IAC) nodules (59 vestibular ganglia and 43 intracanalicular schwannoma) who underwent both single-sequence T2-weighted (T2W) non-contrast enhanced MRI studies and contrast-enhanced T1-weighted (T1W) MRI studies between May 2012 and April 2017 were evaluated. The length, width, distance to the IAC fundus and length/width ratios for all lesions were obtained and compared among groups. Diagnostic performance and cutoff values of the parameters were evaluated with receiver operating characteristics curve analysis. Area under the curve (AUC) value was calculated. RESULTS: Vestibular ganglia have significantly smaller lengths and widths compared to intracanalicular vestibular schwannomas (1.7 ± 0.4 mm and 1.0 ± 0.2 mm versus 5.6 ± 3.0 mm and 3.7 ± 1.5 mm). They are more fusiform in shape compared to vestibular schwannomas (length/width ratio: 1.8 ± 0.4 versus 1.5 ± 0.4). The lesion width demonstrated the highest diagnostic performance (AUC: 0.998). Using a cutoff width of <1.3 mm, the sensitivity, specificity and overall accuracy for diagnosing vestibular ganglia were 97% (57/59), 100% (43/43) and 98% (100/102), respectively. CONCLUSION: Vestibular ganglia may mimic intracanalicular vestibular schwannomas on a single-sequence T2W MRI. However, a fusiform shape and width <1.3 mm increases confidence in the diagnosis of ganglia. Identifying the vestibular ganglion on single-sequence T2W MRI studies may obviate the need for a contrast-enhanced MRI, reducing the risks of contrast administration, additional scanning time and cost.

High Resolution Computed Tomography (HRCT) Imaging Findings of Oval Window Atresia with Surgical Correlation.

INTRODUCTION: Isolated oval window atresia (OWA) is a rare cause of congenital conductive middle ear deafness and may be overlooked owing to the normal appearance of the external ear. This anomaly has been previously described, although the published numbers with both imaging and surgical findings are few. Our aim is to correlate the imaging features of OWA with intraoperative findings. MATERIALS AND METHODS: This is a single-centre retrospective evaluation of patients who were diagnosed with OWA and who received surgery from January 1999 to July 2006. No new case was diagnosed after 2006 to the time of preparation of this manuscript. High resolution computed tomography (HRCT) imaging of the temporal bones of the patients were retrospectively evaluated by 2 head and neck radiologists. Images were evaluated for the absence of the oval window, ossicular chain abnormalities, position of the facial nerve canal, and other malformations. Imaging findings were then correlated with surgical findings. RESULTS: A total of 9 ears in 7 patients (two of whom with bilateral lesions) had surgery for OWA. All patients had concomitant findings of absent stapes footplate with normal, deformed or absent stapes superstructure and an inferiorly displaced facial nerve canal. HRCT was sensitive in identifying OWA and associated ossicular chain and facial nerve abnormalities, which were documented surgically. CONCLUSION: OWA is a rare entity that can be diagnosed with certainty on HRCT, best visualised on coronal plane. Imaging findings of associated middle ear abnormalities, position of the facial nerve canal, which is invariably mal-positioned, and associated deformity of the incus are important for presurgical planning and consent.

Grisel's Syndrome in an Adult After Endoscopic Nasopharyngectomy.

BACKGROUND: Grisel's syndrome is rare in adults, and is characterized by nontraumatic atlanto-axial subluxation secondary to infection. Here, we report a case of Grisel's syndrome occurring after endoscopic nasopharyngectomy. METHODS: A 67-year-old man complained of fever and neck pain with reduced lateral rotation after an endoscopic nasopharyngectomy for recurrent nasopharyngeal carcinoma. Flexion and extension X-rays of the cervical spine demonstrated atlanto-axial subluxation, and magnetic resonance imaging showed infective changes with cervical osteomyelitis. A diagnosis of Grisel's syndrome with cervical spine osteomyelitis was made. A later computed tomography (CT) scan demonstrated subluxation of C1 on C2, as well as the occipital-C1 joint. RESULTS: The patient was treated with intravenous antibiotics and offered surgery for spinal stabilization, but declined. He remained well 15 months post-op on a cervical collar with minimal pain and no neurologic deficits. CONCLUSION: A high index of suspicion for Grisel's syndrome is suggested in patients who have neck pain with reduced range of motion postnasopharyngectomy, and imaging is useful in clinching the diagnosis. LEVEL OF EVIDENCE: 4.

Sudden deafness due to intralabyrinthine haemorrhage: a possible rare late complication of head and neck irradiation.

INTRODUCTION: Radiation injury resulting in sudden, late onset sensorineural hearing loss is a recognised complication in patients who have received head and neck irradiation. We describe the magnetic resonance imaging (MRI) of the internal acoustic canal (IAC) of 3 such patients and postulate a cause for these findings. CLINICAL PICTURE: A total of 63 patients were referred for MRI IAC for sudden-onset sensorineural hearing loss. Of these patients, only 5 patients had abnormal MRI finding in the affected ear and the remaining patients had normal studies. Two patients had acoustic neuromas. Three patients demonstrated high T1-weighted signal in the labyrinths of the affected ears and had past histories of head and neck irradiation. The MRI findings and medical records of these 3 patients were reviewed and described in this case series. OUTCOME: High labyrinthine signal on unenhanced T1-weighted images in the symptomatic ear of these patients was observed, suggesting the possibility of haemorrhage. In the patient who had a history of brain tumour, susceptibility artifacts were also seen in the right hemipons on the gradient-echo images, indicating the presence of paramagnetic substances from previous therapy. CONCLUSION: We postulate that labyrinthine haemorrhage is a rare, late complication of head and neck irradiation, resulting in sudden sensorineural hearing loss.

Basal cell adenomas of the parotid gland: CT scan features.

Basal cell adenoma (BCA) is a rare tumor of the parotid gland, and except for a few case reports, the imaging features of this pathological entity are not well described. We describe the computed tomography (CT) features of 14 cases of histologically proven BCA, the largest series to date. In all cases, the tumor appeared as a round or oval, sharply marginated mass. Three cases showed homogenous enhancement. In the other 11 cases, the enhancement was inhomogeneous, due to either cystic areas, linear bands or stellate-shaped areas of non-enhancement. The latter two patterns have not been previously described in BCA or other parotid tumors, and may therefore aid in distinguishing BCA from other benign parotid neoplasms on CT.

Imaging of facial nerve schwannomas: diagnostic pearls and potential pitfalls.

Schwannomas are uncommon in the facial nerve and account for less than 1% of tumors of temporal bone. They can involve one or more than one segment of the facial nerve. The clinical presentations and the imaging appearances of facial nerve schwannomas are influenced by the topographical anatomy of the facial nerve and vary according to the segment(s) they involve. This pictorial essay illustrates the imaging features of facial nerve schwannomas according to their various anatomical locations and also reviews the pertinent differential diagnoses and potential diagnostic pitfalls.

Approach to intensely enhancing neck nodes.

Cervical node evaluation is one of the most common problems encountered by a radiologist. Here, we present a pictorial review of intensely enhancing neck nodes. While enhancement in a cervical node is a common radiologic finding on contrast-enhanced computed tomography scan, only few conditions cause intense enhancement in cervical nodes. We discuss the common causes of intensely enhancing neck nodes along with pertinent radiologic features and key differentiating points that aid radiologists in reaching a diagnosis. In addition, we discuss certain potential non-nodal mimics, which need to be excluded.