The Relationship Between Arachnoid Cysts and the Subarachnoid Space by Hounsfield Unit Value in Computed Tomography Scans: Identification of Isolated and Communicating Arachnoid Cysts in a Cohort Study Arachnoid cysts and the subarachnoid space
International Clinical Neuroscience Journal,
Vol. 10 No. 1 (2023),
15 January 2023
,
Page e11
Abstract
Background: Arachnoid cysts are formations containing cerebrospinal fluid (CSF). They may be associated with the subarachnoid space. This feature is a factor that can affect the change in the size of arachnoid cysts over time. Hounsfield Unit (HU) value measurements provide rational numeric representation of imaging of tissues in computed tomography (CT) examinations. In this study, we aimed to define isolated or communicated arachnoid cysts, and whether arachnoid cysts communicate with the subarachnoid distance, with the HU values obtained in CT examinations.
Methods: Patients with radiological diagnosis of arachnoid cyst were identified retrospectively by examining the CT database. HU value measurements were recorded over the Picture Archiving and Communication System (PACS) in the area where the arachnoid cyst was detected. HU value measurements are a method that rationally shows the amount of radiograph absorption of tissues in CT examinations. HU value measurements were performed in cerebrospinal fluid (CSF) and arachnoid cysts, and whether arachnoid cysts had equal HU values with CSF. They were defined as homogeneous or heterogeneous by measuring HU values in different regions of arachnoid cysts.
Results: Data on 478 cases were obtained. An average of 2.82 CT scans were detected per case. A change in arachnoid cyst size was detected in 47 (9.8%) cases. In cases of arachnoid cysts of varying size, the mean HU value of arachnoid cysts was 9.32 ± 1.93 (6.43 ± 1.67 in the lateral ventricle and 7.04 ± 1.71 in the fourth ventricle). HU value of arachnoid cysts with a change in size significantly differed from CSF.
Conclusion: Arachnoid cysts with HU values equal to CSF are not real arachnoid cysts, and significant volume changes are not expected. Arachnoid cysts, which have a different HU value than CSF, may secrete a different fluid from CSF. This type of arachnoid cyst is a real cyst that can be detected in various sizes on CT examinations at different times since they are not in communication with the subarachnoid space.
- Arachnoid cyst; Computed tomography; Cyst; Cerebrospinal fluid; Magnetic resonance imaging
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References
Carbone J, Sadasivan AP. Intracranial arachnoid cysts: review of natural history and proposed treatment algorithm. Surg Neurol Int. 2021;12:621. doi: 10.25259/sni_946_2021.
Li L, Begbie F, Grimmond N, Kontorinis G. Arachnoid cysts on magnetic resonance imaging: just an incidental finding? J Laryngol Otol. 2020;134(5):424-30. doi: 10.1017/ s0022215120000808.
Hayes MJ, TerMaath SC, Crook TR, Killeffer JA. A review on the effectiveness of surgical intervention for symptomatic intracranial arachnoid cysts in adults. World Neurosurg. 2019;123:e259-e72. doi: 10.1016/j.wneu.2018.11.149.
Rabiei K, Jaraj D, Marlow T, Jensen C, Skoog I, Wikkelsø C. Prevalence and symptoms of intracranial arachnoid cysts: a population-based study. J Neurol. 2016;263(4):689-94. doi: 10.1007/s00415-016-8035-1.
Algin O. Evaluation of the communication between arachnoid cysts and neighboring cerebrospinal fluid spaces by T2W 3D-SPACE with variant flip-angle technique at 3 T. J Comput Assist Tomogr. 2018;42(5):816-21. doi: 10.1097/ rct.0000000000000751.
Sahap SK, Unal S, Fitoz S. The unique features of middle cranial fossa and Sylvian fissure arachnoid cysts in children: MRI evaluation. Childs Nerv Syst. 2022. doi: 10.1007/ s00381-022-05712-3.
Algin O, Hakyemez B, Gokalp G, Korfali E, Parlak M. Phase-contrast cine MRI versus MR cisternography on the evaluation of the communication between intraventricular arachnoid cysts and neighbouring cerebrospinal fluid spaces. Neuroradiology. 2009;51(5):305-12. doi: 10.1007/s00234- 009-0499-6.
Yildiz H, Erdogan C, Yalcin R, Yazici Z, Hakyemez B, Parlak M, et al. evaluation of communication between intracranial arachnoid cysts and cisterns with phase-contrast cine MR imaging. AJNR Am J Neuroradiol. 2005;26(1):145-51.
Morizane K, Fujibayashi S, Otsuki B, Sakamoto T, Tsutsumi R, Odate S, et al. Clinical and radiological features of spinal extradural arachnoid cysts: valve-like mechanism involving the nerve root fiber as a possible cause of cyst expansion. J Orthop Sci. 2018;23(3):464-9. doi: 10.1016/j. jos.2018.01.005.
Halani SH, Safain MG, Heilman CB. Arachnoid cyst slit valves: the mechanism for arachnoid cyst enlargement. J Neurosurg Pediatr. 2013;12(1):62-6. doi: 10.3171/2013.4.peds12609.
Santamarta D, Aguas J, Ferrer E. The natural history of arachnoid cysts: endoscopic and cine-mode MRI evidence of a slit-valve mechanism. Minim Invasive Neurosurg. 1995;38(4):133-7. doi: 10.1055/s-2008-1053473.
García-Conde M, Martín-Viota L. [Arachnoid cysts: embriology and pathology]. Neurocirugia (Astur). 2015;26(3):137-42. doi: 10.1016/j.neucir.2015.02.003. [Spanish].
Al-Holou WN, Terman S, Kilburg C, Garton HJ, Muraszko KM, Maher CO. Prevalence and natural history of arachnoid cysts in adults. J Neurosurg. 2013;118(2):222-31. doi: 10.3171/2012.10.jns12548.
Basaldella L, Orvieto E, Dei Tos AP, Della Barbera M, Valente M, Longatti P. Causes of arachnoid cyst development and expansion. Neurosurg Focus. 2007;22(2):E4. doi: 10.3171/ foc.2007.22.2.4.
Li L, Begbie F, Grimmond N, Kontorinis G. Arachnoid cysts on magnetic resonance imaging: just an incidental finding? J Laryngol Otol. 2020;134(5):424-30. doi: 10.1017/ s0022215120000808.
Helland CA, Aarhus M, Knappskog P, Olsson LK, Lund- Johansen M, Amiry-Moghaddam M, et al. Increased NKCC1 expression in arachnoid cysts supports secretory basis for cyst formation. Exp Neurol. 2010;
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