Acoustic neuroma CT
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Acoustic neuroma Microchapters | |
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Diagnosis | |
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Acoustic neuroma CT On the Web | |
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American Roentgen Ray Society Images of Acoustic neuroma CT | |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [3]Associate Editor(s)-in-Chief: Simrat Sarai, M.D. [4]
Overview
Head CT scan may be diagnostic of acoustic neuroma. Findings on CT scan diagnostic of acoustic neuroma include erosion, and widening of the internal acoustic canal.[1]
CT
- CT scans with bone windows can also be of prognostic significance as the extent of widening of the IAC and the extent of tumor growth anterior and caudal to the IAC are predictive of postoperative hearing loss.
- If MRI cannot be done on patient, high resolution CT scanning with and without contrast is an alternative.
- On MRI and CT scans, vestibular schwannoma can be seen as enhancing lesions in the region of the internal auditory canal with variable extension into the cerebellopontine angle.
- CT scans with bone windows can also be of prognostic significance.
- CT may show erosion and widening of the internal acoustic canal.
- The density of these tumors on non-contrast imaging is variable, and often they are hard to see, especially on account of beam hardening and streak artifact form the adjacent petrous temporal bone.
- Contrast enhancement is present, but can be underwhelming, especially in larger lesions with cystic components.[1]
- Well-performed scanning can demonstrate tumors 1-2 mm in diameter. However, even with intravenous contrast enhancement thin-cut CT scanning can miss tumors as large as 1.5 cm even.
- Fine-cut CT scanning of the internal auditory canal with contrast can detect medium-size or large tumor but are not reliable imaging techniques to detect a tumor smaller than 1-1.5 cm.
References
- ↑ 1.0 1.1 Acoustic Schwannoma. Radiopedia(2015) http://radiopaedia.org/articles/acoustic-schwannoma Accessed on October 2 2015
- ↑ Image courtesy of Dr Frank Gaillard. Radiopaedia (original file [1]).[http://radiopaedia.org/licence Creative Commons BY-SA-NC
- ↑ Image courtesy of Dr Prashant Mudgal. Radiopaedia (original file [2]).[http://radiopaedia.org/licence Creative Commons BY-SA-NC