[Sudden onset vertigo: imaging work-up]

Vertigo and dysequilibrium are a frequent cause of medical consultation. Clinical evaluation is essential. Some cases of vertigo are diagnosed clinically while others require imaging, sometimes emergently (suspected stroke). MRI is the imaging modality of choice to assess the labyrinth (labyrinthitis? labyrinthine hemorrhage?), internal auditory canal (vestibular schwannoma? other tumor?…) and brain parenchyma including all structures of the auditory pathways: vestibular nuclei, vestibulocerebellar tract, tracts involved with ocular motricity, vestibular cortex… Multiple central etiologies exist: stroke, multiple sclerosis, tumor… However, some etiologies are best depicted with CT, especially lesions of the labyrinth: cholesteatoma, trauma, suspected dehiscence of the superior semicircular canal, suspected labyrinthine fistula… Finally, imaging may be negative (Benign Paroxysmal Positional Vertigo, Meniere's disease, vestibular neuritis, migraine…), merely reducing the differential diagnosis.

Diffusion-weighted magnetic resonance imaging of the temporal bone

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.

Magnetic resonance imaging of cholesteatoma: an update

OBJECTIVE

To report on the value and limitations of new MRI techniques in pre- and post-operative MRI of cholesteatoma. The current value of magnetic resonance imaging (MRI) in diagnosing congenital, acquired, and post-operative recurrent or residual cholesteatoma is described.

METHODOLOGY AND RESULTS

High resolution computed tomography (HRCT) is still considered the imaging modality of choice for detecting acquired or congenital middle ear cholesteatoma. However, MRI may provide additional information on the delineation and extension of cholesteatoma and on potential complications. Detecting post-operative residual or recurrent cholesteatoma with HRCT was shown to be inaccurate due to the technique's low sensitivity and specificity.

CONCLUSIONS

Recently, improvements in MRI techniques have led to a more accurate diagnoses of cholesteatoma using delayed contrast enhanced T1-weighted imaging and diffusion-weighted imaging.

Imaging of intralabyrinthine schwannomas: a retrospective study of 52 cases with emphasis on lesion growth

BACKGROUND AND PURPOSE

Only a few case reports and small series of intralabyrinthine schwannomas (ILSs) have been reported. The purpose of this study was to assess prevalence, MR characteristics, location, clinical management, and growth potential/patterns of ILSs in the largest series reported.

MATERIALS AND METHODS

Lesion localization, MR characteristics, lesion growth, and clinical management were reviewed in 52 patients diagnosed with an ILS between February 1991 and August 2007 in 2 referral centers. The number of ILSs and vestibulocochlear schwannomas in the cerebellopontine angle/internal auditory canal was compared to assess the prevalence.

RESULTS

ILSs most frequently originate intracochlearly, are hyperintense on unenhanced T1-weighted images, enhance strongly after gadolinium administration, and are sharply circumscribed and hypointense on thin heavily T2-weighted 3D images. The scala tympani is more frequently or more extensively involved than the scala vestibuli. Follow-up MR imaging, available in 27 patients, showed growth in 59% of subjects. Growth was seen from the scala tympani into the scala vestibuli and from the scala vestibuli to the saccule and vice versa. Twelve lesions were resected, and the diagnosis of ILS histopathologically confirmed.

CONCLUSION

ILSs can account for up to 10% of all vestibulocochlear schwannomas in centers specializing in temporal bone imaging, grow in more than 50%, and are most frequently found intracochlearly, often anteriorly between the basal and second turn. Cochlear ILSs most often originate in the scala tympani and only later grow into the scala vestibuli. Growth can occur from the cochlea into the vestibule or vice versa through the anatomic open connection between the perilymphatic spaces in the scala vestibuli and around the saccule.

Imaging of the opacified middle ear

Middle ear opacification on imaging studies performed in a non-traumatic setting mostly reflects chronic inflammatory/infectious disease. In some of these patients an underlying cholesteatoma will be found. High-resolution computed tomography examinations and magnetic resonance imaging are often used in the work-out of the disease. High-resolution computed tomography of the opacified middle ear serves to describe the status of the ossicular chain, and its suspensory apparatus, as well as the status of the tympanic and mastoid wall. When ossicular erosions are visualized, the probability of a present cholesteatoma is about 90%. Whereas high-resolution computed tomography is not able to differentiate cholesteatoma from other types of opacification, magnetic resonance imaging is. The combined use of delayed post-Gd T1-weighted images and non-EPI based DWI seems to be the actual best option on this matter.

Cervical ectopic thymus presenting as a painless neck mass in a child

Ectopic cervical thymus is an uncommon entity to be considered in the differential diagnosis of neck masses in infants and children. The sonographic appearance of a hyporeflective mass with characteristic internal linear hyperreflections situated along the path of the thymopharyngeal duct should suggest diagnosis. On MRI, signal intensities differ significantly from other more common neck mass lesions in children such as a branchiogenic cyst, hemangioma and lymphangioma. Diagnosis can be confirmed by performing a sonographically guided thru-cut biopsy.

Arachnoid granulations of the posterior temporal bone wall: imaging appearance and differential diagnosis

Arachnoid granulations are rarely seen on high-resolution CT (HRCT) at the posterior temporal bone wall, where they appear as erosions, without bone spicules and often with a lobulated surface. Differential diagnosis includes endolymphatic sac tumor, paraganglioma, chordoma, and chondromatous and metastatic tumors. MR imaging can confirm the diagnosis because arachnoid granulations behave like CSF without gadolinium enhancement. This report aims to illustrate the appearance and differentiation of temporal bone arachnoid granulations on HRCT and MR imaging.

Single-shot, turbo spin-echo, diffusion-weighted imaging versus spin-echo-planar, diffusion-weighted imaging in the detection of acquired middle ear cholesteatoma

Diagnosis of acquired middle ear cholesteatoma on MR imaging is mostly done on late postgadolinium T1-weighted MR images and/or echo-planar (EPI) diffusion-weighted (DWI) MR images. We describe the appearance of a case of a complicated attical middle ear cholesteatoma on single-shot (SS) turbo spin-echo (TSE) DWI compared with EPI-DWI. This case suggests a higher reliability of SS TSE-DWI in the diagnosis of acquired middle ear cholesteatoma.

Tumors and tumor-like lesions of the jaw: radiolucent lesions

Radiolucent lesions within the jaws represent a whole variety of lesions. Generally, they can be classified into two categories. The first category comprises well circumscribed lesions, either unilocular, multilobular or multilocular. They may be further subdivided into odontogenic or nonodontogenic lesions. The key feature that distinguishes these two subgroups is the relationship with the underlying dentition. Poorly circumscribed radiolucent lesions are the second category and consist of acute infectious disease and primary or metastatic malignancies. Although many of these lesions may present with non-specific imaging characteristics, careful analysis of a combination of imaging parameters may suggest a presumptive diagnosis. This article discusses the imaging features on different imaging techniques that may be useful in the characterization of these lesions.

Tumors and tumor-like lesions of the jaw mixed and radiopaque lesions

Radiopaque lesions and lesions of mixed radioopacity are far less frequent than their radiolucent counterparts. Included in this spectrum are infectious and metastatic disease, inherited and developmental disorders and rare tumoral lesions. This article deals with the imaging features that may assist in the (differential) diagnosis of these lesions. in many instances, the radiological characterization is typical (osteoma, enostoma, fibrous dysplasia, Paget disease...), obviating the need for further invasive histological confirmation. Other lesions may share overlapping clinical, radiological and pathological features. In these cases, correlation of histopathological diagnosis with clinical findings and imaging features is of utmost importance for a correct diagnosis.

CT and MR imaging of congential abnormalities of the inner ear and internal auditory canal

The embryology of the inner ear must be known as many of the inner ear malformations present as a result of the arrest during the various stages of embryology. These malformations are described in this "embryologic" perspective and specific names for certain malformations are no longer used. Both CT and MR can be used to look at inner ear malformations but often both techniques are complementary. However, CT is preferred when associated middle- or external ear malformations must be excluded. Magnetic resonance is preferred when subtle changes in the membranous labyrinth or abnormalities of the nerves in the internal auditory canal must be visualised. The CT and MR technique must however be adapted as more and more subtle congenital malformations can only be seen when the right technique is used. The heavily T2-weighted gradient-echo or fast spin-echo MR techniques are mandatory if malformations of the inner ear must be excluded. The purpose of this paper is to describe the techniques used to study these patients and to give an overview of the most frequent and important congenital malformations which can be found in the inner ear and internal auditory canal/cerebellopontine angle.

MRI screening for acoustic neuroma without gadolinium: value of 3DFT-CISS sequence

To evaluate the efficacy of a gradient-echo sequence (3DFT-CISS) in the diagnosis of acoustic neuromas, two independent observers twice reviewed the images of the temporal bones of 83 patients. Contrast-enhanced T1-weighted spin echo images were used as the reference, showing 18 acoustic neuromas, including 5 purely intracanalicular and one intralabyrinthine tumours. High sensitivity (89-94%), specificity (94-97%) and accuracy (94-95%) were found. Intraobserver (kappa 0.93-1) and interobserver (kappa 0.83-0.84) reproducibility were very good. The smallest intracanalicular tumour was overlooked twice by both observers; the intralabyrinthine tumour once by one observer. All tumours were detected with a less stringent decision criterion, at the expense of lower specificity.

Imaging of maxillo-facial trauma

The maxillofacial skeleton is vulnerable to injury. Radiological evaluation of facial injury can be difficult due to the complex anatomy and the difficulties in obtaining high-quality imaging studies in the severely traumatised patient. Adequate imaging is nevertheless necessary to obtain satisfactory clinical results. This paper gives a review of common and some less common injuries that may be encountered in facial trauma.

Estimation of thyroid gland volume by spiral computed tomography

The objective of this study was to test the accuracy of CT for the estimation of the volume of enlarged thyroid glands. An unenhanced spiral CT scan of neck and upper mediastinum was obtained in 36 patients with an enlarged thyroid gland. By manual segmentation the surface of the thyroid gland on 5-mm-thick slices was calculated; these surfaces were multiplied by the slice interval (10 mm) and summated to obtain the volume of the gland. All patients underwent a total or subtotal thyroidectomy. 1 cm3 of thyroid gland tissue was considered to weigh 1 g. A good correlation was found between the volume estimated by CT and the weight at pathological examination of the resected gland (r = 0.98, p < 0.001), with a mean difference of + 12 % (range: + 57.3 to -13.9 %). The volume calculation is reproducible among different observers (r = 0.99, p < 0.01). Computed tomography allows an easy, reliable and reproducible volume determination of enlarged thyroid glands.

Imaging features in 35 cases of submucosal laryngeal mass lesions

We evaluated the clinical and radiological findings in 35 patients with submucosal laryngeal masses. The presenting symptoms were hoarseness, stridor, dysphagia and external neck mass. In 20 cases an important delay between the onset of symptoms and direct laryngoscopy was found. There was a considerable delay between laryngoscopy and definitive diagnosis in 13 cases due to repeated negative biopsies. Computed tomography pointed out the location and extension of the masses in all cases. In 27 mass lesions CT allowed correct prediction of the malignant or benign character of the lesion. In 6 cases no reliable differentiation could be made. The lesion was mischaracterised in 2 cases. Magnetic resonance imaging was also performed in 4 patients, and showed the extent of the lesion better; in 1 case MRI narrowed the differential diagnosis. In the case of a negative biopsy result, radiological findings should incite further investigation, reducing the possible delay between the onset of symptoms and definitive diagnosis.

Selective embolization of a superior gluteal artery pseudoaneurysm associated with von Willebrand's disease

We report the case of an iliopsoas hematoma caused by an iliolumbar branch pseudoaneurysm, following a relatively minor blunt pelvic trauma. Laboratory investigation revealed an as yet undiagnosed von Willebrand's disease. The pseudoaneurysm was successfully embolized superselectively and the hematoma, causing femoral neuropathy, was subsequently drained surgically without major bleeding.

Late-onset Bochdalek hernia with a rare postoperative complication: case report

We report a case of a 7-year-old-girl with a late-presenting Bochdalek hernia. The postoperative course was complicated by splenic torsion and subsequent total splenic infarction. Total splenic infarction due to splenic torsion has been reported in children with "wandering spleen" and in incarcerated Bochdalek hernias, but to our knowledge, not as a postoperative complication of Bochdalek hernia repair.

Eosinophilic granuloma of the head and neck: CT and MRI features in three cases

We report the radiological findings and more specifically the MRI features in three typical cases of Langerhans' cell histiocytosis of the head and neck. All three cases were of solitary eosinophilic granuloma of bone: two mandibular and one temporal bone lesion. Reports on the MRI features of head and neck eosinophilic granulomas are rare.

Solitary plasmacytoma of the greater sphenoid wing with secondary submandibular soft tissue metastasis

We report the follow-up of a case of solitary plasmacytoma of bone in the posterolateral orbital wall previously published in this journal. The patient presented three years after initial diagnosis and treatment with a submandibular soft tissue metastasis, probably in a lymph node. Reports of lymph node metastases from solitary plasmacytoma of bone are rare.

Inflammatory fibroid polyp of the ileum

We report a patient who presented with recurrent right upper quadrant colics after a previous cholecystectomy. Radiological examination revealed the presence of a polypoid mass in the ileum caused by an anatomo-pathologically proven inflammatory fibroid polyp (IFP) in the ileum. Clinical and pathological aspects related to this rare benign lesion are discussed.