Artikel
Radiographic demonstration of a fistula of the lateral semicircular canal with Digital Volume Tomography
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Autoren
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Martin Bremke
- ENT Dep., Philipps University, Marburg, Germany
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Carsten V. Dalchow
- ENT Dep., Philipps University, Marburg, Germany
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Siegfried Bien
- Department of Neuroradiology, Philipps University, Marburg, Germany
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Jochen A. Werner
- ENT Dep., Philipps University, Marburg, Germany
| Veröffentlicht: | 7. September 2006 |
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Gliederung
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Background: Digital Volume Tomography (DVT) is an extension of the panoramic tomography. With its high resolution of 0,125 mm DVT demonstrating smallest bony lesions of the lateral skull base, its value of visualizing pathologies of the semicircular canals even in early stages is examined.
Patients und Methods: Between may 2003 and august 2005 four-hundred thirty-five patients with the history of chonic otitis media were examined by DVT (Accu-I-tomo, Morita, Japan). Six patients demonstrated an erosion of the lateral semicircular canal in DVT. All patients had already received a tympanoplasty, two of them with a radical mastoidectomy because of the occurrence of a cholesteatoma. The vertigo described by those six patients was examined by specific testing of the labyrinth. One patient even demonstrated a positive fistula symptom during his examination which could be provocated by application of pressure on the tragus. The erosion of the lateral semicircular canal predicted by DVT was then evaluated during surgery, where a repair of a fistula, if present, was performed using autogenous tissues (temporalis fascia, bone pate, and fibrin glue).
Results: A radiographic diagnosis of a fistula of the lateral semicircular canal of six patients was made by DVT with its high resolution and artefact free imaging of the labyrinth and cochlea. One patient even offered an additional erosion of the posterior semicircular canal in DVT. All lesions of the semicircular canals predicted in DVT were verified during surgery, even the additional fistula of the posterior semicircular canal and repaired. One patient showed a deafness caused by a large cholesteatoma, while another patient with a re-occurrence of a cholesteatoma offered a fistula of the lateral and posterior semicircular canal. All patients showed normal vestibular testing in the postoperative check-up.
Conclusion: Digital Volume Tomography showed its value in the preoperative diagnosis of an erosion of the semicircular canals. Especially by means of its high resolution and detailed visualization of bony anatomical landmarks of the lateral skull base, the precise localisation of lesions is feasible for an exact planning of a surgical intervention. In comparison to conventional CT, DVT offers a higher resolution combined with a lower radiation dosage.
