Arachnoid cyst MRI
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Arachnoid cyst Microchapters |
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Diagnosis |
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Treatment |
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Case Studies |
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Arachnoid cyst MRI On the Web |
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American Roentgen Ray Society Images of Arachnoid cyst MRI |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: José Eduardo Riceto Loyola Junior, M.D.[2]
Overview
On brain/spine MRI, arachnoid cysts are characterized by cystic images with similar density to CSF and non-enhancing borders, mostly found in the middle cranial fossa while they only rarely occur in the spinal cord. MRIs are more adequate than CT scans for evaluating arachnoid cysts.
MRI
- MRIs are better to diagnose and evaluate the extent of the arachnoid cyst than the CT Scan;
- Most cysts (50-60%) are found in the floor of the middle cranial fossa, while 1/4 to 1/3 of occur in the posterior fossa, particularly in the retrocerebellar, cerebellopontine, and quadrigeminal plate cisterns. Rarely, they may be found in the spinal cord.[1][2]
- Demonstrate the exact location, extent, and relationship of the cyst;
- Can differentiate arachnoid from epidermoid cysts (arachnoid cysts are identical to CSF, while epidermoid present a higher signal with FLAIR and reduced diffusion with DWI, making them appear brighter than CSF).
- CSF signal is seen within the cyst;
- Eventually, arachnoid cysts may contain proteinaceous fluid or blood, which can cause diagnostic confusion.[3]
Differential Diagnosis
| Intraventricularly: | Colloid cysts |
| Intraparenchymally: | Parasitic infections, cystic metastases |
| Porencephalic cysts | |
| Craniopharyngiomas | |
| Holoprosencephalies | |
| Agenesis of corpus callosum | |
| Defect in the hemispheral cleavage | |
| Dandy-Walker complex (posterior fossa cysts) |
References
- ↑ Robertson, S. J., S. M. Wolpert, and V. M. Runge. "MR imaging of middle cranial fossa arachnoid cysts: temporal lobe agenesis syndrome revisited." American journal of neuroradiology 10.5 (1989): 1007-1010.
- ↑ "Arachnoid Cysts - Imaging". Medscape. 06/26/2020. Check date values in:
|date=(help) - ↑ "Arachnoid Cysts". MedPix. 06/26/2020. Check date values in:
|date=(help) - ↑ Cincu, Rafael, Amit Agrawal, and Jose Eiras. "Intracranial arachnoid cysts: current concepts and treatment alternatives." Clinical neurology and neurosurgery 109.10 (2007): 837-843.
==MRI Examples of Arachnoid Cysts
Patient #1: Left middle cranial fossa arachnoid cyst
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Cor T2
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Sag T1
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Axial T1 FLAIR
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Axial T2
Patient #2: CT and MR images demonstrate a hemorrhagic arachnoid cyst
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CT
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Sag T1
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Ax T1
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Ax FLAIR
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Ax T2
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Ax T1 with GAD
