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KEY FACTS
Terminology
Imaging
Top Differential Diagnoses
Pathology
Clinical Issues
Diagnostic Checklist
TERMINOLOGY
Abbreviations
- Arachnoid granulation (AG)
- Aberrant arachnoid granulation (AbAG)
Synonyms
- Pacchionian depressions, granulations, or bodies
- When large → "giant" AG
- When in sphenoid bone and T-bone → AbAG (arachnoid pit)
Definitions
- Arachnoid villi: Term used to describe smaller AG
- AG: Enlarged arachnoid villi projecting from subarachnoid space (SAS) into major dural venous sinus (DVS) lumen
- AbAG: AG that penetrates dura but fails to reach DVS, typically in sphenoid or temporal bone
- Rarely other bones like parietal, occipital bone
- Also referred to as arachnoid pits or osteodural defects
IMAGING
General Features
CT Findings
MR Findings
Imaging Recommendations
DIFFERENTIAL DIAGNOSIS
PATHOLOGY
General Features
Gross Pathologic & Surgical Features
Microscopic Features
CLINICAL ISSUES
Presentation
Demographics
Natural History & Prognosis
Treatment
DIAGNOSTIC CHECKLIST
Consider
Image Interpretation Pearls
Selected References
- Freeman CW et al: Variations of the CNS venous system mimicking pathology: spectrum of imaging findings. J Neuroimaging. ePub, 2019
- Sade R et al: Brain herniation into the transverse sinuses' arachnoid granulations in the pediatric population investigated with 3 T MRI. Acta Neurol Belg. 119(2):225-31, 2019
- Taieb G et al: Reversible giant arachnoid granulations. Neurology. 91(24):1107-8, 2018
- Battal B et al: Brain herniations into the dural venous sinuses or calvarium: MRI of a recently recognized entity. Neuroradiol J. 27(1):55-62, 2014
- De Keyzer B et al: Giant arachnoid granulations mimicking pathology. A report of three cases. Neuroradiol J. 27(3):316-21, 2014
- Settecase F et al: Spontaneous lateral sphenoid cephaloceles: anatomic factors contributing to pathogenesis and proposed classification. AJNR Am J Neuroradiol. 35(4):784-9, 2014
- Alonso RC et al: Spontaneous skull base meningoencephaloceles and cerebrospinal fluid fistulas. Radiographics. 33(2):553-70, 2013
- Barañano CF et al: Sternberg's canal: fact or fiction? Am J Rhinol Allergy. 23(2):167-71, 2009
- La Fata V et al: CSF leaks: correlation of high-resolution CT and multiplanar reformations with intraoperative endoscopic findings. AJNR Am J Neuroradiol. 29(3):536-41, 2008
- Lloyd KM et al: Imaging of skull base cerebrospinal fluid leaks in adults. Radiology. 248(3):725-36, 2008
- Schuknecht B et al: Nontraumatic skull base defects with spontaneous CSF rhinorrhea and arachnoid herniation: imaging findings and correlation with endoscopic sinus surgery in 27 patients. AJNR Am J Neuroradiol. 29(3):542-9, 2008
- Haroun AA et al: Arachnoid granulations in the cerebral dural sinuses as demonstrated by contrast-enhanced 3D magnetic resonance venography. Surg Radiol Anat. 29(4):323-8, 2007
- Amlashi SF et al: Intracranial hypertension and giant arachnoid granulations. J Neurol Neurosurg Psychiatry. 75(1):172, 2004
- Liang L et al: Normal structures in the intracranial dural sinuses: delineation with 3D contrast-enhanced magnetization prepared rapid acquisition gradient-echo imaging sequence. AJNR Am J Neuroradiol. 23(10):1739-46, 2002
- Casey SO et al: Prevalence of arachnoid granulations as detected with CT venography of the dural sinuses. AJNR Am J Neuroradiol. 18(5):993-4, 1997
- Leach JL et al: Normal appearance of arachnoid granulations on contrast-enhanced CT and MR of the brain: differentiation from dural sinus disease. AJNR Am J Neuroradiol. 17(8):1523-32, 1996
- Roche J et al: Arachnoid granulations in the transverse and sigmoid sinuses: CT, MR, and MR angiographic appearance of a normal anatomic variation. AJNR Am J Neuroradiol. 17(4):677-83, 1996
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References
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Tables
KEY FACTS
Terminology
Imaging
Top Differential Diagnoses
Pathology
Clinical Issues
Diagnostic Checklist
TERMINOLOGY
Abbreviations
- Arachnoid granulation (AG)
- Aberrant arachnoid granulation (AbAG)
Synonyms
- Pacchionian depressions, granulations, or bodies
- When large → "giant" AG
- When in sphenoid bone and T-bone → AbAG (arachnoid pit)
Definitions
- Arachnoid villi: Term used to describe smaller AG
- AG: Enlarged arachnoid villi projecting from subarachnoid space (SAS) into major dural venous sinus (DVS) lumen
- AbAG: AG that penetrates dura but fails to reach DVS, typically in sphenoid or temporal bone
- Rarely other bones like parietal, occipital bone
- Also referred to as arachnoid pits or osteodural defects
IMAGING
General Features
CT Findings
MR Findings
Imaging Recommendations
DIFFERENTIAL DIAGNOSIS
PATHOLOGY
General Features
Gross Pathologic & Surgical Features
Microscopic Features
CLINICAL ISSUES
Presentation
Demographics
Natural History & Prognosis
Treatment
DIAGNOSTIC CHECKLIST
Consider
Image Interpretation Pearls
Selected References
- Freeman CW et al: Variations of the CNS venous system mimicking pathology: spectrum of imaging findings. J Neuroimaging. ePub, 2019
- Sade R et al: Brain herniation into the transverse sinuses' arachnoid granulations in the pediatric population investigated with 3 T MRI. Acta Neurol Belg. 119(2):225-31, 2019
- Taieb G et al: Reversible giant arachnoid granulations. Neurology. 91(24):1107-8, 2018
- Battal B et al: Brain herniations into the dural venous sinuses or calvarium: MRI of a recently recognized entity. Neuroradiol J. 27(1):55-62, 2014
- De Keyzer B et al: Giant arachnoid granulations mimicking pathology. A report of three cases. Neuroradiol J. 27(3):316-21, 2014
- Settecase F et al: Spontaneous lateral sphenoid cephaloceles: anatomic factors contributing to pathogenesis and proposed classification. AJNR Am J Neuroradiol. 35(4):784-9, 2014
- Alonso RC et al: Spontaneous skull base meningoencephaloceles and cerebrospinal fluid fistulas. Radiographics. 33(2):553-70, 2013
- Barañano CF et al: Sternberg's canal: fact or fiction? Am J Rhinol Allergy. 23(2):167-71, 2009
- La Fata V et al: CSF leaks: correlation of high-resolution CT and multiplanar reformations with intraoperative endoscopic findings. AJNR Am J Neuroradiol. 29(3):536-41, 2008
- Lloyd KM et al: Imaging of skull base cerebrospinal fluid leaks in adults. Radiology. 248(3):725-36, 2008
- Schuknecht B et al: Nontraumatic skull base defects with spontaneous CSF rhinorrhea and arachnoid herniation: imaging findings and correlation with endoscopic sinus surgery in 27 patients. AJNR Am J Neuroradiol. 29(3):542-9, 2008
- Haroun AA et al: Arachnoid granulations in the cerebral dural sinuses as demonstrated by contrast-enhanced 3D magnetic resonance venography. Surg Radiol Anat. 29(4):323-8, 2007
- Amlashi SF et al: Intracranial hypertension and giant arachnoid granulations. J Neurol Neurosurg Psychiatry. 75(1):172, 2004
- Liang L et al: Normal structures in the intracranial dural sinuses: delineation with 3D contrast-enhanced magnetization prepared rapid acquisition gradient-echo imaging sequence. AJNR Am J Neuroradiol. 23(10):1739-46, 2002
- Casey SO et al: Prevalence of arachnoid granulations as detected with CT venography of the dural sinuses. AJNR Am J Neuroradiol. 18(5):993-4, 1997
- Leach JL et al: Normal appearance of arachnoid granulations on contrast-enhanced CT and MR of the brain: differentiation from dural sinus disease. AJNR Am J Neuroradiol. 17(8):1523-32, 1996
- Roche J et al: Arachnoid granulations in the transverse and sigmoid sinuses: CT, MR, and MR angiographic appearance of a normal anatomic variation. AJNR Am J Neuroradiol. 17(4):677-83, 1996
