Septum Pellucidum Research Articles

Septo-optic dysplasia plus: A case report for reviewing and recognizing this condition

Septo-optic dysplasia is a congenital neurological condition with multifactorial etiology, characterized by septum pellucidum agenesis and/or corpus callosum dysgenesis, hypoplasia of the chiasm or optic nerves, and hormonal dysfunction with pituitary or hypothalamic alterations. Diagnosis requires two of these criteria and magnetic resonance is the imaging test of choice. Most cases present with abnormalities of cortical development in the form known as septo-optic dysplasia plus. While seizures and neurodevelopmental disorders are the dominant neurological manifestations, this entity is highly heterogeneous and has multiple clinical and radiological findings to consider. We present the case of a 35-year-old man with a history of cranioencephalic trauma in childhood and remission for refractory focal epilepsy associated with cognitive deficit. During the initial examination, the simple cranial tomography showed septum pellucidum agenesis and corpus callosum dysgenesis. Brain magnetic resonance imaging revealed agenesis of the septum pellucidum, irregularity and anomalous thickening of the cerebral cortex in frontal lobes and perisylvian region, heterotopic gray matter in frontal lobes and left fronto-insular region, mild supratentorial ventriculomegaly, atypical appearance of the corpus callosum rostrum, and hypoplasia of the chiasm and optic nerves. Although agenesis of the septum pellucidum was the key finding in this case, it is not present in all patients. The relevance of magnetic resonance imaging for the detailed evaluation of other involved structures, highlighting optic nerve hypoplasia, is fundamental in the radiologist’s diagnostic workup and this entity recognition.

Iodine-Based Dual-Energy Computed Tomography After Mechanical Thrombectomy Predicts Secondary Neurologic Decline from Cerebral Edema After Severe Stroke.

Patients with severe stroke are at high risk of secondary neurologic decline (ND) from the development of malignant cerebral edema (MCE). However, early infarcts are hard to diagnose on conventional head computed tomography (CT). We hypothesize that high-energy (190keV) virtual monochromatic imaging (VMI) from dual-energy CT (DECT) imaging enables earlier detection of ND from MCE. Consecutive patients with severe stroke with National Institute of Health Stroke Scale (NIHSS) scores > 15 and DECT within 10h of mechanical thrombectomy from May 2020 to March 2022 were included. We excluded patients with parenchymal hematoma type 2 transformation. Retrospective analysis of clinical and novel variables included the VMI Alberta Stroke Program Early CT Score (ASPECTS), total iodine content, and VMI infarct volume. The primary outcome was secondary ND, defined using a composite outcome variable of clinical worsening (increase in NIHSS score ≥ 4 or decrease in Glasgow Coma Scale score > 2) or malignant radiographical edema (midline shift ≥ 5mm at the level of the septum pellucidum). Fisher's exact test and Wilcoxon's test were used for univariate analysis. Logistic regression was used to develop prediction models for categorical outcomes. Eighty-four patients with severe stroke with a median age of 67.5 (interquartile range [IQR] 57-78) years and an NIHSS score of 22 (IQR 18-25) were included. Twenty-nine patients had ND. The VMI ASPECTS, total iodine content, and VMI infarct volume were associated with ND. The VMI ASPECTS, VMI infarct volume, and total iodine content were predictors of ND after adjusting for age, sex, initial NIHSS score, and tissue plasminogen activator administration, with areas under the receiver operating characteristic curve (AUROC) of 0.691 (95% confidence interval [CI] 0.572-0.810), 0.877 (95% CI 0.800-0.954), and 0.845 (95% CI 0.750-0.940). By including all three predictors, the model achieved an AUROC of 0.903 (95% CI 0.84-0.97) and was cross-validated by the leave one out method, with an AUROC of 0.827. The VMI ASPECTS and VMI infarct volume from DECT are superior to the conventional CT ASPECTS and are novel predictors for secondary ND due to MCE after severe stroke. Clinical trial registration ClinicalTrials.gov identifier: NCT04189471.

Rare presentations of glioblastoma multiforme in the septum pellucidum: illustrative case.

Glioblastoma multiforme (GBM), a high-grade primary brain tumor, presents a formidable challenge in neuro-oncology because of its aggressive nature, infiltrative growth, and limited response to treatment. The septum pellucidum represents an uncommon and unexpected location for GBM, adding complexity to the diagnosis and management of this rare intracranial malignancy. A 69-year-old male with a previous history of prostate carcinoma presented to an outside hospital with a 2-week history of a "trance-like state" and cognitive decline. Initial head computed tomography showed prominent ventricles without distinct mass lesions. Upon admission, magnetic resonance imaging demonstrated a mass within the inferior septum pellucidum extending to the third and both lateral ventricles. Biopsy findings indicated a GBM, World Health Organization central nervous system tumor grade 4, with immunopositivity for glial fibrillary acidic protein and a Ki-67 labeling index of 60%-70%. Identifying only 5 cases in more than 60 years of literature, this systematic review illustrates the diverse clinical presentations, diagnostic advancements, and management approaches for septum pellucidum GBM. https://thejns.org/doi/10.3171/CASE23770.

Utility of routine postoperative imaging in adults undergoing primary ventriculoperitoneal shunts.

There is currently no consensus on the usefulness of postoperative imaging after ventriculoperitoneal (VP) shunt insertion in adults. The aim of this study was to investigate the utility of routine postoperative imaging (CT head scans and radiographs) following primary VP shunt insertion in a general adult population treated at a tertiary neurosurgical centre. Patients undergoing primary VP shunt insertion between 2017-2021 were included. Actions taken based on routine postoperative imaging and need for subsequent shunt revision were recorded. 236 patients were included. The median age was 63years (range 17-90). There was a slight female preponderance (121/236, 51.3%). The median follow-up was 38.5months (3.1 - 60.5months). Acute intervention was employed in 9 patients (3.9%) on the basis of routine postoperative CT head scan. Routine postoperative radiographs did not result in reoperation. Around a quarter (28.8%) of patients had a shunt revision, most of whom underwent urgent primary shunt insertions. Postoperative ventricular catheter characteristics (position of shunt tip, tip relation to septum pellucidum, and intraventricular catheter distance) were not predictive of shunt revision. Surgical urgency (emergency vs. elective procedures) was associated with long-term shunt revision (OR = 2.80, 95% CI 1.42 - 5.53, p = 0.003). Routine postoperative imaging rarely led to reoperation in adult patients undergoing primary VP shunt insertion. Patients undergoing emergency shunt insertions were at the highest risk for requiring revision.

Exploring the septum pellucidum: Short review of anatomical insights and the clinical impact of septum pellucidum and cavum septi pellucidi

BackgroundThe septum pellucidum (SP) is a thin, triangular, and delicate structure in the brain. It consists of two layers of white and gray matter and topographically is located between the lateral ventricles. The SP is part of the limbic system, which involves emotions, behavior, and memory. AimThis concise review provides an overview of the anatomy, development, and clinical significance of the SP, with a specific focus on cavum septi pellucidi (CSP). It also discusses its implications for brain function and its potential link to neurological disorders. ConclusionsAs an essential structure within the limbic system, the SP and its associated variations, like CSP, offer valuable insights into brain development and function, particularly concerning emotions, memory, and psychiatric disorders. Understanding the role of the septum pellucidum and its developmental anomalies may shed light on various neuropsychiatric conditions and help guide future research and clinical practices.

Fetal MRI findings, etiology, and outcome in prenatally diagnosed schizencephaly.

Schizencephaly is a rare brain anomaly which is increasingly detected in utero. There are limited data on the etiology and outcomes in fetal schizencephaly to guide workup and counselling. We aim to determine the associated imaging findings, etiology, and outcomes in schizencephaly detected in utero. This retrospective cohort study included 22 fetuses with a total of 34 schizencephaly defects identified by keyword search of fetal MRI reports from 1996-2022 followed by image review. Follow-up fetal and postnatal imaging, when available, were reviewed. Data on demographics, etiology, and outcomes were extracted from the electronic medical record. The schizencephaly defect was open in 28/34, most common in the MCA territory (23/34), and commonly involved the frontal (16/34) lobe. Additional intracranial abnormalities were seen in all fetuses including other cortical malformations (CM, 13/22), abnormal posterior fossa (12/22), abnormal corpus callosum (10/20), and intraparenchymal hemorrhage (9/22).The cause of schizencephaly was classified as secondary (as evidenced by intraparenchymal hemorrhage at schizencephaly, monochorionic twin gestation, infection, or maternal/placental risk factor) in 64% (14/22), potentially genetic in 9% (2/22), and unknown in 27% (6/22). Among those liveborn (n=8), the following outcomes were observed: postnatal death (1/8), tube feeding (1/7), shunted hydrocephalus (1/7), epilepsy (4/7). Among those >1 year of age, cerebral palsy (4/5) and speech delay or intellectual disability (3/5) were common. CM remote from schizencephaly was associated with epilepsy (p=0.03). On postnatal imaging, open defects often involuted (8/11) and there were high rates of new/additional findings (4/6). In this cohort, fetal schizencephaly was always associated with additional intracranial abnormalities. In most cases, there was evidence that schizencephaly was likely secondary to prior injury. Imaging characteristics may provide clues regarding neurodevelopmental outcome. Postnatal imaging is crucial in assessing evolution as well as for detection of additional abnormalities. ICH = intracranial hemorrhage; CM = cortical malformation; VM = ventriculomegaly; DGN = deep grey nuclei; SP = septum pellucidum; IPH = intraparenchymal hemorrhage; CC = corpus callosum; PMG = polymicrogyria; PVNH = periventricular nodular heterotopia; TTTS = twin-twin transfusion syndrome; GA = gestational age; CP = cerebral palsy.

Cavum Septum Pellucidum in Former American Football Players: Findings From the DIAGNOSE CTE Research Project.

Exposure to repetitive head impacts (RHI) is linked to the development of chronic traumatic encephalopathy (CTE), which can only be diagnosed at post-mortem. The presence of a cavum septum pellucidum (CSP) is a common finding in post-mortem studies of confirmed CTE and in neuroimaging studies of individuals exposed to RHI. This study examines CSP in living former American football players, investigating its association with RHI exposure, traumatic encephalopathy syndrome (TES) diagnosis, and provisional levels of certainty for CTE pathology. Data from the DIAGNOSE CTE Research Project were used to compare the presence and ratio of CSP in former American football players (n = 175), consisting of former college (n = 58) and former professional players (n = 117), and asymptomatic unexposed controls without RHI exposure (n = 55). We further evaluated potential associations between CSP measures and cumulative head impact index (CHII) measures (frequency, linear acceleration, and rotational force), a TES diagnosis (yes/no), and a provisional level of certainty for CTE pathology (suggestive, possible, and probable). Former American football players exhibited a higher CSP presence and ratio than unexposed asymptomatic controls. Among player subgroups, professional players showed a greater CSP ratio than former college players and unexposed asymptomatic controls. Among all football players, CHII rotational forces correlated with an increased CSP ratio. No significant associations were found between CSP measures and diagnosis of TES or provisional levels of certainty for CTE pathology. This study confirms previous findings, highlighting a greater prevalence of CSP and a greater CSP ratio in former American football players compared with unexposed asymptomatic controls. In addition, former professional players showed a greater CSP ratio than college players. Moreover, the relationship between estimates of CHII rotational forces and CSP measures suggests that cumulative frequency and strength of rotational forces experienced in football are associated with CSP. However, CSP does not directly correlate with TES diagnosis or provisional levels of certainty for CTE, indicating that it may be a consequence of RHI associated with rotational forces. Further research, especially longitudinal studies, is needed for confirmation and to explore changes over time.

Can cavum septum pellucidum width and length measurements also be reliable indicators of corpus callosum measurements in normal fetuses?

Can cavum septum pellucidum width and length measurements also be reliable indicators of corpus callosum measurements in normal fetuses?

Finding of Isolated Agenesis of the Septum Pellucidum in Neurotrauma: Report of an Unusual Case

Finding of Isolated Agenesis of the Septum Pellucidum in Neurotrauma: Report of an Unusual Case

Topographical anatomy of the septum verum and its white matter connections

The human septum verum represents a small but clinically important region of the brain. Based on the results of animal experiments, the stimulation of its medial part was recently proposed with various indications like epilepsy or cognitive impairment after traumatic brain injury. The aim of our study was to present the anatomical relationships of the human septum verum using fiber dissection and histological analysis to support its research and provide essential information for future deep brain stimulation therapies. 16 human cadaveric brains were dissected according to Klingler’s method. To validate our macroscopical findings, 12 samples obtained from the dissected brains and 2 additional specimens from unfrozen brains were prepared for histological examinations. We identified the following white matter connections of the septum verum: (1) the precommissural fibers of the fornix; (2) the inferior fascicle of the septum pellucidum; (3) the cingulum; (4) the medial olfactory stria; (5) the ventral amygdalofugal pathway; (6) the stria medullaris of the thalamus and (7) the stria terminalis. Moreover, we could distinguish a less-known fiber bundle connecting the postcommissural column of the fornix to the stria medullaris of the thalamus and the anterior thalamic nuclei. In this study we present valuable anatomical information about this region to promote safe and effective deep brain stimulation therapies in the future.

Evaluation and Significance of Nonvisualization of the Cavum Septum Pellucidum on Prenatal Ultrasonography.

The identification of the cavum septum pellucidum (CSP) is an integral part of the routine second trimester fetal anatomy scan. The absence or nonvisualization of the CSP has significant clinical implications and requires further evaluation and counseling for the pregnant patient. The aim of this review is to review the importance of accurate sonographic identification of the CSP and the underlying pathologies that can be associated with nonvisualization of this structure. A literature review was performed with PubMed using key words including CSP, fetal anatomy ultrasound, and fetal anomalies. The absence of the CSP is associated with several central nervous system pathologies, all with a wide range of phenotypic outcomes, ranging from normal to very severe or lethal. Most obstetrician-gynecologists will have a patient in whom a CSP is not identified on fetal ultrasound. Thus, it is imperative to have a general understanding of this relatively common entity.

MRI analysis of neurodevelopmental anatomy in myelomeningocele: prenatal vs postnatal repair.

Compared with postnatal repair, prenatal myelomeningocele (MMC) repair is associated with improved motor function and decreased need for cerebrospinal fluid (CSF) diversion. It is unknown how prenatal surgery alters neuroanatomical structures identifiable on magnetic resonance imaging (MRI). The purpose of this study was to use MRI to compare neurodevelopmental anatomy in patients undergoing fetal MMC repair compared with those undergoing postnatal repair. This was a retrospective review of neonates who underwent prenatal or postnatal MMC repair at our institution between 2016 and 2021. Imaging data, including prenatal ultrasound and pre- and postnatal MRI examinations, if available, were retrieved. We analyzed anatomical findings characteristically seen on MRI of the neuroaxis in patients with MMC and compared imaging findings between patients with prenatal vs postnatal MMC repair. The study population included 61 patients who underwent surgical repair for MMC during the 6-year study period, of whom 25 underwent prenatal repair and 36 postnatal repair. CSF diversion was required in 24% of the prenatally repaired cohort vs 67% of the postnatally repaired cohort (P = 0.001). On postnatal MRI, a syrinx was present in 13% of the prenatally repaired cohort vs 42% in the postnatally repaired cohort (P = 0.02). Postnatal corpus callosal (CC) morphology was abnormal in 54% of the prenatally repaired cohort vs 53% of the postnatally repaired cohort (P = 0.92), while falx morphology was normal in 92% of the prenatally repaired cohort vs 34% of the postnatally repaired cohort (P < 0.001). On postnatal MRI, patients in the prenatally repaired cohort had a shorter tentorium-to-foramen-magnum distance compared with those in the postnatally repaired cohort (mean, 18.43 mm vs 22.42 mm; P = 0.01), a larger foramen magnum diameter (mean, 22.87 mm vs 18.94 mm; P < 0.001) and a smaller degree of hindbrain herniation (mean, 1.53 mm vs 8.72 mm; P < 0.001). The cerebral aqueduct was patent in 79% of the prenatally repaired cohort vs 100% of the postnatally repaired cohort on postnatal MRI (P = 0.008). Between the two cohorts, at postnatal MRI there was no significant difference in the presence of gray-matter heterotopia, presence of the septum pellucidum or size of the massa intermedia. We report variations in developmental neuroanatomy in patients with MMC, including rates of CC dysgenesis, gray-matter heterotopia and additional cranial and spinal MRI findings. Compared to postnatal surgery, prenatal surgery is associated with changes to infratentorial anatomy, with minimal effect on supratentorial brain development. This information will be useful in counseling parents affected by fetal MMC and in understanding how prenatal repair of MMC affects brain development. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.

Evaluation and Significance of Nonvisualization of the Cavum Septum Pellucidum on Prenatal Ultrasonography

ABSTRACT Importance The identification of the cavum septum pellucidum (CSP) is an integral part of the routine second trimester fetal anatomy scan. The absence or nonvisualization of the CSP has significant clinical implications and requires further evaluation and counseling for the pregnant patient. Objective The aim of this review is to review the importance of accurate sonographic identification of the CSP and the underlying pathologies that can be associated with nonvisualization of this structure. Evidence Acquisition A literature review was performed with PubMed using key words including CSP, fetal anatomy ultrasound, and fetal anomalies. Results The absence of the CSP is associated with several central nervous system pathologies, all with a wide range of phenotypic outcomes, ranging from normal to very severe or lethal. Relevance Most obstetrician-gynecologists will have a patient in whom a CSP is not identified on fetal ultrasound. Thus, it is imperative to have a general understanding of this relatively common entity. Target Audience Obstetricians and gynecologists, family physicians Learning Objectives After completing this activity, the learner will be able to describe the CSP, the importance of accurate identification on ultrasonography, and the pitfalls to avoid/be aware of; explain the additional workup required in the setting of absent CSP including utility of antenatal ultrasound, fetal magnetic resonance imaging, and genetic counseling; and discuss the various pathologies that have an association with the absence of the CSP and patient counseling regarding the absence of the CSP.

A rare case of ethmoidal encephalocele with corpus callosal dysgenesis

A 6 mm defect is seen over anterior aspect of face in between both orbits with a 2.6 x 2.5 cm sized cystic collection herniating through the defect possibly arising from ethmoid s/o Ethmoidal encephalocele. CSP (Cavum Septum Pellucidum) is not well visualised with bilateral parallel orientation of lateral ventricles.

Predictive factors and outcomes in treating shunt malfunctions: a case study of multiloculated hydrocephalus

Background. Endoscopic septostomy is a secure and reliable endoscopic for treating multiloculated hydrocephalus. The ventriculoperitoneal (VP) shunt procedure is known as the gold standard. However, shunt malfunction often occurs. The combination of these has been reported to reduce the incidence of recurrent malfunction and reestablish communication between isolated intraventricular compartments making a special ventricular cavity. Case presentation. A one-year-old child who had previously communicated hydrocephalus complained of vomiting, appeared agitated, and had difficulty falling asleep. The patient had a history of congenital diseases. The patient had VP shunt Keen dextra and sinistra fitted to manage the hydrocephalus before, but one side of the VP shunt was found to be malfunctioning. Physical examination revealed a sunset eye phenomenon with a head circumference of 48 cm dry and clean ventricular parietal shunt surgery scars. The findings of the multiloculated cystic lesions on the endoscopic, agenesis of the septum pellucidum, and dysgenesis of the corpus callosum. Discussion. The patient was scheduled for endoscopic cyst fenestrations surgery, endoscopic third ventriculostomy (ETV), VP shunt Kocher dextra low pressure, and aff VP shunt Keen dextra that was evaluated with preoperative and postoperative CT scans which showed the sulcus and gyrus prominent had improved, slightly open in fissure Sylvie, reduced size in ventricular (the average decrease was 5 cm3) that decreased intracranial pressure which improved the patient’s quality of life. Conclusion. Endoscopy septostomy and VP shunt are a great combination to treat multiloculated hydrocephalus and VP shunt malfunction.

Neonatal cerebral ultrasound: anatomical variants and age-related diseases.

Cerebral ultrasound is a non-invasive imaging technique widely used for the assessment of brain anatomy and diseases in neonates and infants. Indeed, it allows a precise characterization of common variants such as cavum septum pellucidum or diseases like intraventricular hemorrhage. The aim of this pictorial review is to provide a comprehensive overview of the main ultrasound features of the most common cerebral anatomical variants and disorders detectable by cerebral ultrasound using an age-related approach which could support non-subspecialized radiologists.

Solid pilocytic astrocytoma in cavum septum pellucidum: a description of two cases and an analysis of misdiagnosis

Solid pilocytic astrocytoma in cavum septum pellucidum: a description of two cases and an analysis of misdiagnosis

Schizencephaly: Etiopathogenesis, Classification, Therapeutic, and Rehabilitative Approach

AbstractSchizencephaly is an uncommon anomaly in neuronal migration characterized by complete clefts that extend from the pia mater to the ependymal surface of the ventricular system. These clefts are encompassed by displaced gray matter and filled with cerebrospinal fluid. Typically, they are found most often in the frontal lobe or the area around the lateral sulcus and can occur on one or both sides. The size, location, and type of these clefts carry significant clinical and prognostic implications. Moreover, they are frequently associated with other central nervous system malformations, including the absence of the septum pellucidum, septo-optic dysplasia, optic nerve hypoplasia, pachygyria, polymicrogyria, cortical dysplasia, heterotopia, and dysplasia of the corpus callosum. Occurrence of schizencephaly is almost always sporadic but its etiopathogenesis is yet to be fully understood. Most likely environmental factors, including exposure to teratogens, viral infections, and maternal factors, operate jointly with genetic defects. To date COL4A1, EMX2, SHH, and SIX3 are the genes identified as possible pathogenetic target. It is interesting to notice that schizencephaly is commonly seen in abandoned or adopted children, as proof of causative effect of intrautero insults. Clinical presentations widely vary and symptoms include a spectrum of cognitive impairment, limb paresis/tetraparesis, and epileptic seizures either with early or late onset; anyway, none of these symptoms is ever-present and patients with schizencephaly can also have normal neurocognitive and motor development. Diagnostic gold standard for schizencephaly is magnetic resonance imaging, which allows to identify and characterize typical clefts. Treatment of schizencephaly is symptomatic and supportive and depends on the severity of morbidity resulting from the malformation. Therapy includes antiepileptic drugs, psychomotor rehabilitation, and in selected cases surgical approach.

Lymphoma of the central nervous system originating from the septum pellucidum region: Two case reports with literature review.

Central nervous system lymphoma (CNSL) originating from the septum pellucidum is exceptionally rare, presenting unique diagnostic and therapeutic complexities. This case report aims to elucidate the diagnostic challenges, treatment strategies, and outcomes of this rare manifestation. By documenting this case, we seek to enhance understanding within the medical community and contribute valuable insights to the management of CNSL, particularly in atypical locations. A 45-year-old female presented with persistent headaches, blurred vision, and motor weakness, prompting a thorough neurological evaluation. Imaging revealed an enhancing mass in the septum pellucidum, leading to the diagnosis of CNSL. The patient's concerns encompassed not only the physical symptoms but also the emotional impact of her diagnosis and treatment journey. Diagnostic confirmation of CNSL involved cerebrospinal fluid analysis and imaging findings, highlighting the challenge of distinguishing lymphoma from other intracranial pathologies. The case underscores the importance of comprehensive diagnostic evaluation in rare CNSL presentations. Multidisciplinary management included high-dose methotrexate-based chemotherapy and corticosteroids, with consideration for neurosurgical intervention. Psychosocial support and self-care strategies were integrated into the treatment plan to address holistic patient needs. Monitoring revealed a positive treatment response, with a reduction observed in the septum pellucidum mass. Regular assessments ensured adherence to interventions and management of treatment-related side effects, contributing to favorable outcomes and improved quality of life for the patient. This case emphasizes the significance of meticulous diagnostic evaluation and personalized treatment approaches in managing rare CNSL presentations. Collaboration among specialists and comprehensive patient support is paramount in optimizing outcomes and addressing the multifaceted challenges posed by CNSL in unique anatomical locations.

Arachnoid cyst in the pediatric patient: What the radiologist needs to know.

Arachnoid cysts are the most common incidentally discovered intracranial lesions on imaging and the most common cystic intracranial lesions. They may be developmental or secondary. A relative lack of recent literature and any comprehensive radiological review on arachnoid cysts has led to a general lack of awareness among radiologists of symptomatic or complicated arachnoid cysts. This is particularly concerning in pediatric patients. While arachnoid cysts are asymptomatic in most cases, they can cause clinical symptoms in a minority of cases, especially when they occur in unusual sites. These include intraventricular locations where they may cause hydrocephalus, the basal cisterns where they may compress cranial nerves, the cerebellopontine angle where they have to be differentiated from a number of cystic lesions, the cavum septum pellucidum or cavum velum interpositum, the choroid fissure where they can entrap the temporal horn and compress the hippocampus, the posterior fossa where they need to be differentiated from other posterior fossa cystic lesions, and within the spinal canal where there is a concern for cord or nerve root compression. Larger cysts are more prone to complications such as mass effect, hemorrhage, and rupture. Hemorrhage and rupture often present with acute symptoms. Ruptured cysts lose their characteristic imaging appearance and can mimic several ominous pathologies. It therefore becomes vital to accurately diagnose these cases as complications of pre-existing arachnoid cysts for appropriate management. A detailed review of all diagnostic imaging aspects of arachnoid cysts will help fill in the existing information void on this important entity.