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Petrous bone extension of middle-ear acquired cholesteatoma
Y Robert1, F Dubrulle, S Carcasset
1Service de Radiologie Ouest, Hôpital Claude Huriez CHU, Lille, France.
Purpose:
To describe CT and MR features of extension to the petrous bone, which is a rare complication of acquired cholesteatoma (AC).
Material And Methods:
Postcontrast CT was performed in 4 patients, in axial (n=4) and coronal planes (n=2). The section thickness was 1.2 or 2.5 mm. MR was performed in 3 cases, using T1- and T2-weighted images (n=3) and postcontrast T1-weighted images (n=2).
Results:
CT demonstrated a well-outlined lesion involving the petrous bone (n=4). Density could be assessed in 3 cases, showing a hypodense unenhanced mass. Lateral (n=1), superior (n=2), and posterior (n=2) semicircular canals were affected in 3 patients. AC extended to the vestibula, cochlea, and internal acoustic meatus (IAM) in 3 patients. Two ACs extended to the level of IAM, whereas 2 extended further, to the petrous apex. In one case the sphenoid sinus was affected. On MR imaging the lesion was hypointense relative to brain on T1-weighted images and hyperintense on T2-weighted images. MR imaging helped to delineate the lesion and to distinguish it from other cystic lesions of the petrous bone.
Conclusion:
CT and MR offer accurate preoperative assessment of the extension of cholesteatoma, which helps to choose the surgical approach.
Insights
Computed tomography (CT) and magnetic resonance (MR) imaging can accurately assess the spread of acquired cholesteatoma (AC) to the petrous bone. These imaging techniques are crucial for surgical planning in this rare complication.
Area of Science:
- Radiology
- Otolaryngology
- Medical Imaging
Background:
- Acquired cholesteatoma (AC) is a destructive epithelial growth in the middle ear.
- Extension to the petrous bone is a rare but serious complication of AC.
- Accurate preoperative assessment is vital for effective surgical management.
Purpose of the Study:
- To describe the computed tomography (CT) and magnetic resonance (MR) imaging features of petrous bone extension in acquired cholesteatoma (AC).
- To highlight the diagnostic capabilities of CT and MR in evaluating this rare AC complication.
Main Methods:
- Retrospective review of CT and MR imaging in 4 patients with AC extending to the petrous bone.
- CT performed with postcontrast in axial and coronal planes (1.2 or 2.5 mm thickness).
- MR performed with T1- and T2-weighted and postcontrast T1-weighted sequences.
Main Results:
- CT revealed well-defined lesions involving the petrous bone, often hypodense and unenhanced.
- Affected structures included semicircular canals, vestibule, cochlea, internal acoustic meatus (IAM), and petrous apex.
- MR imaging delineated the lesion, differentiating it from other cystic lesions and showing characteristic signal intensities (hypointense on T1, hyperintense on T2).
Conclusions:
- CT and MR imaging provide accurate preoperative assessment of AC extension to the petrous bone.
- These imaging modalities aid in determining the extent of disease and planning the appropriate surgical approach.