Acoustic neuroma CT: Difference between revisions
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{{CMG}}{{AE}}{{Simrat}} | {{CMG}}{{AE}}{{Simrat}} | ||
==Overview== | ==Overview== | ||
[[Head]] [[CT scan]] may be diagnostic of acoustic neuroma. Findings on CT scan diagnostic of acoustic neuroma include erosion | [[Head]] [[CT scan]] may be [[Diagnosis|diagnostic]] of acoustic neuroma. Findings on [[Computed tomography|CT scan]] diagnostic of acoustic neuroma include erosion and widening of the [[Internal auditory meatus|internal acoustic canal]]. | ||
==CT== | ==CT== | ||
*CT | *[[Computed tomography|CT scan]] with [[bone]] windows can be of [[prognostic]] significance as the extent of widening of the [[internal auditory meatus]] and the extent of [[tumor]] growth [[Anatomical terms of location|anterior]] and [[caudal]] to the [[internal auditory meatus]] are predictive of postoperative [[hearing loss]]. | ||
*On [[Computed tomography|CT scan]], vestibular [[schwannoma]] can be seen as an enhancing [[lesions|lesion]] in the region of the [[Internal auditory meatus|internal auditory canal]] with variable extension into the [[cerebellopontine]] angle.<ref>{{Cite journal | |||
| author = [[C. Matthies]], [[M. Samii]] & [[S. Krebs]] | | author = [[C. Matthies]], [[M. Samii]] & [[S. Krebs]] | ||
| title = Management of vestibular schwannomas (acoustic neuromas): radiological features in 202 cases--their value for diagnosis and their predictive importance | | title = Management of vestibular schwannomas (acoustic neuromas): radiological features in 202 cases--their value for diagnosis and their predictive importance | ||
| Line 16: | Line 17: | ||
| pmid = 9055285 | | pmid = 9055285 | ||
}}</ref> | }}</ref> | ||
* | *[[Computed tomography|CT]] may show erosion and widening of the [[Internal auditory meatus|internal acoustic canal]]. | ||
*[[Contrast]] enhancement is present, but can be underwhelming, especially in larger [[lesions]] with [[Cyst|cystic]] components. | |||
*Well-performed scanning can demonstrate tumors 1-2 mm in diameter. However, even with [[intravenous]] contrast enhancement, thin-cut [[Computed tomography|CT]] scanning can miss [[Tumor|tumors]] as large as 1.5 cm. | |||
*Fine-cut [[Computed tomography|CT]] scanning of the [[Internal auditory meatus|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. | |||
[[File:Acoustic.neuroma.ct.1.jpg|thumb|none|200px|[[Computed tomography|CT]] image of a patient with acoustic neuroma]] <ref>Image courtesy of Dr Frank Gaillard. [http://www.radiopaedia.org Radiopaedia] (original file [http://radiopaedia.org/cases/acoustic-schwannoma-2]).[http://radiopaedia.org/licence Creative Commons BY-SA-NC</ref> | |||
[[File: CT of neurofibromatosis type 2.jpg|thumb|none|200px|[[Computed tomography|CT]] image of [[Neurofibromatosis type II|neurofibromatosis type 2]]]] | |||
*[[Contrast]] enhancement is present, but can be underwhelming, especially in larger [[lesions]] with cystic components. | |||
*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 | |||
*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. | |||
[[File:Acoustic.neuroma.ct.1.jpg|thumb|none|200px|CT acoustic neuroma]] <ref>Image courtesy of Dr Frank Gaillard. [http://www.radiopaedia.org Radiopaedia] (original file [http://radiopaedia.org/cases/acoustic-schwannoma-2]).[http://radiopaedia.org/licence Creative Commons BY-SA-NC</ref> | |||
[[File: CT of neurofibromatosis type 2.jpg|thumb|none|200px|CT neurofibromatosis type 2]] | |||
<ref>Image courtesy of Dr Prashant Mudgal. [http://www.radiopaedia.org Radiopaedia] (original file [http://radiopaedia.org/cases/neurofibromatosis-type-ii-2]).[http://radiopaedia.org/licence Creative Commons BY-SA-NC</ref> | <ref>Image courtesy of Dr Prashant Mudgal. [http://www.radiopaedia.org Radiopaedia] (original file [http://radiopaedia.org/cases/neurofibromatosis-type-ii-2]).[http://radiopaedia.org/licence Creative Commons BY-SA-NC</ref> | ||
=== Differentiating Acoustic Neuroma from Meningioma | === Differentiating Acoustic Neuroma from Meningioma based CT Scans === | ||
The most important differential diagnosis for Acoustic neuroma is Meningioma of Pontine angle, so it is vital to distinguish these two diseases. As you see below this diagram demonstrate this differences of these two disease in CT Scan.<ref>{{Cite journal|last=A. M611er, A. Hatam and H. Olivecrona|first=|date=1978|title=The Differential Diagnosis of Pontine Angle Meningioma and Acoustic Neuroma with Computed Tomography|url=|journal=Neuroradilogy|volume=|pages=|via=}}</ref>{{familytree/start}} | The most important differential diagnosis for Acoustic neuroma is Meningioma of Pontine angle, so it is vital to distinguish these two diseases. As you see below this diagram demonstrate this differences of these two disease in CT Scan.<ref>{{Cite journal|last=A. M611er, A. Hatam and H. Olivecrona|first=|date=1978|title=The Differential Diagnosis of Pontine Angle Meningioma and Acoustic Neuroma with Computed Tomography|url=|journal=Neuroradilogy|volume=|pages=|via=}}</ref>{{familytree/start}} | ||
{{familytree | | | | | | | | | |,|-| A01 |~|~| A02 |~|~| A03 |-|.| | |A01= <13cm3 |A02= Volume |A03= >35cm3 }} | {{familytree | | | | | | | | | |,|-| A01 |~|~| A02 |~|~| A03 |-|.| | |A01= <13cm3 |A02= Volume |A03= >35cm3 }} | ||
Revision as of 18:27, 26 April 2019
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Acoustic neuroma Microchapters | |
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Diagnosis | |
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Treatment | |
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Case Studies | |
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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.
CT
- CT scan with bone windows can be of prognostic significance as the extent of widening of the internal auditory meatus and the extent of tumor growth anterior and caudal to the internal auditory meatus are predictive of postoperative hearing loss.
- On CT scan, vestibular schwannoma can be seen as an enhancing lesion in the region of the internal auditory canal with variable extension into the cerebellopontine angle.[1]
- CT may show erosion and widening of the internal acoustic canal.
- Contrast enhancement is present, but can be underwhelming, especially in larger lesions with cystic components.
- 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.
- 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.
Differentiating Acoustic Neuroma from Meningioma based CT Scans
The most important differential diagnosis for Acoustic neuroma is Meningioma of Pontine angle, so it is vital to distinguish these two diseases. As you see below this diagram demonstrate this differences of these two disease in CT Scan.[4]
| <13cm3 | Volume | >35cm3 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| No | Increased attenuation | Yes | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| No | Marked calcification | Yes | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| No | Oval shape | Yes | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Yes | Round shape | Mostly No | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Acoustic Neuroma | No | Tumor reaches dorsum sellae anteriorly | Yes | Meningioma | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Mostly No | Apparently broad attachment to bone | Yes | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| No | Center of tumor anterior to porus | Sometimes Yes | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| No | Tumor reaches > 2 cm above dorsum | Mostly Yes | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Sometimes | Peripheral edema | No | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Mostly Yes | Widening of porus or other bone changes | No | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
References
- ↑ C. Matthies, M. Samii & S. Krebs (1997). "Management of vestibular schwannomas (acoustic neuromas): radiological features in 202 cases--their value for diagnosis and their predictive importance". Neurosurgery. 40 (3): 469–481. PMID 9055285. Unknown parameter
|month=ignored (help) - ↑ 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
- ↑ A. M611er, A. Hatam and H. Olivecrona (1978). "The Differential Diagnosis of Pontine Angle Meningioma and Acoustic Neuroma with Computed Tomography". Neuroradilogy.