J. W. Casselman

Implications of SENSE MR in routine clinical practice

Sensitivity encoding (SENSE) uses multiple MRI receive coil elements to encode spatial information in addition to traditional gradient encoding. Requiring less gradient encodings translates into shorter scan times, which is extremely beneficial in many clinical applications. SENSE is available to routine diagnostic imaging for the past 2 years. This paper highlights the use of SENSE with scan time reduction factors up to 6 in contrast-enhanced MRA, routine abdominal imaging, mammography, cardiac and neuro imaging. It is shown that SENSE has opened new horizons in both routine and advanced MR 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.

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.

PSEUDODYNAMIC MAGNETIC-RESONANCE-IMAGING IN THE DIAGNOSIS OF TEMPOROMANDIBULAR-JOINT DYSFUNCTION.

Two imaging methods are useful in diagnosing internal derangements of the temporomandibular joint: arthrography and magnetic resonance imaging (MRI). Clinical and pseudodynamic MRI findings of 200 temporomandibular joints in 100 patients were evaluated and compared. In 66.5% of the joints, there was a positive correlation between both diagnostic methods. MRI showed the possibility to correct the clinical diagnosis in more than half of the remaining joints. The other half of the joints are a source of discussion and suggest that MRI has some difficulties in detecting the exact disk position, especially in joints with an anterior disk displacement with early reduction. MRI revealed degenerative changes in 43.5% of the joints. They were often seen in joints with a disk displacement without reduction, even in young patients. Pseudodynamic MRI is especially useful in the differential diagnosis of a closed lock and should certainly be done when disk surgery is planned.

Pathology of the vestibulocochlear nerve

There is a large scala of pathology affecting the vestibulocochlear nerve. Magnetic resonance imaging is the method of choice for the investigation of pathology of the vestibulocochlear nerve. Congenital pathology mainly consists of agenesis or hypoplasia of the vestibulocochlear nerve. Tumoral pathology affecting the vestibulocochlear nerve is most frequently located in the internal auditory canal or cerebellopontine angle. Schwannoma of the vestibulocochlear nerve is the most frequently found tumoral lesion followed by meningeoma, arachnoid cyst and epidermoid cyst. The most frequently encountered pathologies as well as some more rare entities are discussed in this chapter.

The Bony Obliteration Tympanoplasty in Pediatric Cholesteatoma: Long-term Safety and Hygienic Results

Objective: To present the safety and hygienic results of a 5-year longitudinal study in a pediatric population undergoing surgery for extensive cholesteatoma using a canal wall up approach with bony obliteration of the mastoid and epitympanic space. Study Design: Retrospective consecutive study. Patients: Thirty-three children (⩽18 yr) undergoing surgery for cholesteatoma (34 ears) between 1997 and 2009. Interventions: Therapeutic. Setting: Tertiary referral center. Main Outcome Measures: 1) Residual and recurrent cholesteatoma rates at 5-year postsurgery, 2) postoperative waterproofing and hygienic status of the ear, and 3) required operation rate to achieve the safety and hygienic goals. Results: At 5 years no patients were lost in follow-up. This consecutive series design is rare in chronical otitis media treatment reporting. The standard residual rate at 5 years was 5.8%, representing two residual cholesteatomas in the middle ear. The standard recurrence rate at 5 years was 2.9%, representing one recurrent cholesteatoma. At 5-year follow-up all ears were free of otorrhea and waterproof and all external ear canals were patent and self-cleaning. The operation rate to reach this safety and hygienic status was 1.5 operations per ear at 5-year follow-up. Conclusion: The use of a canal wall up approach with obliteration of the mastoid cavity and epitympanic space to surgically treat cholesteatoma in children results in low residual and recurrence rates and a high rate of trouble-free ears in the long term.

Les applications de la diffusion en imagerie : tête et cou

Diffusion-weighted MR imaging of the head and neck Diffusion weighted MR imaging is increasingly being used for the imaging of head and neck pathology. This imaging technique now replaces CT and conventional MR imaging for the initial diagnosis of cholesteatoma and detection of recurrent disease. Diffusion weighted imaging has also proven to be valuable for additional head and neck pathologies and currently has three main indications: detection and characterization of tumors, regional tumor staging, and prediction of tumor response to treatment and follow-up. In the recent months, several publications have discussed the use of diffusion weighted imaging for head and neck pathology and this technique has become virtually indispensable for the MR imaging evaluation of the head and neck.

Consensus statement: Long-term results of ABI in children with complex inner ear malformations and decision making between CI and ABI

Consensus statement : Long-term results of ABI in children with complex inner ear malformations and decision making between CI and ABI

Long-term Results of Troublesome CWD Cavity Reconstruction by Mastoid and Epitympanic Bony Obliteration (CWR-BOT) in Adults.

Objective: To present the long-term surgical outcome of the bony mastoid and epitympanic obliteration technique with canal wall reconstruction (CWR-BOT) in adults with an unstable cavity after previous canal wall-down surgery for extensive cholesteatoma. Study Design: Retrospective study. Interventions: Therapeutic. Setting: Tertiary referral center. Patients: Fifty consecutive adult patients undergoing a CWR-BOT between 1998 and 2009. Main Outcome Measure(s): (A) Recurrence and residual rates of cholesteatoma, (B) postoperative hygienic status of the ear, including postoperative aspect of the tympanic membrane and external ear canal integrity (EAC), (C) functional outcome, and (D) long-term safety issues. Results: (A) The percentage of ears remaining safe without recurrent or residual disease after CWR-BOT was 96% after a mean follow-up time of 101.8 months. Recurrent cholesteatoma occurred in 2% (nu200a=u200a1) and a residual cholesteatoma was detected in 2% (nu200a=u200a1) of the patients. (B) A safe dry, and trouble-free graft and selfcleaning EAC was achieved in 94%

Imaging of Cholesteatoma

Whereas imaging of cholesteatoma was limited to CT scan a decade ago, MRI has become in the past few years an indispensable tool in the evaluation of the cholesteatoma patient as well as prior to first stage surgery in describing the exact location and extent of the cholesteatoma as well as prior to second stage surgery in selecting patients for second stage surgery. This chapter describes the different types of cholesteatoma as well as the different types of cholesteatoma surgery. Emphasis is put on current state-of-the art imaging of cholesteatoma as well in the non-operated patient as well as in the patient prior to second stage surgery.