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PubMed This is a summary of 13 peer-reviewed journal articles Updated
Neurology

Understanding Your Child's MRI: Subtypes and Anatomy

At a Glance

Schizencephaly is primarily categorized on an MRI by the type of cleft—closed-lip (walls touching) or open-lip (separated by fluid)—and whether it affects one side of the brain (unilateral) or both sides (bilateral). These details, along with other brain structure variations, help doctors guide your child's care and development.

Return to Overview

When you look at your child’s MRI report, the technical language used to describe the brain’s structure can feel like a foreign language. Understanding these terms is a vital step in mapping out your child’s unique needs. Schizencephaly is defined by where the cleft starts and ends, how many sides of the brain it affects, and which other brain structures are involved.

Mapping the Cleft

To understand schizencephaly, it helps to visualize the brain’s “layers.” Every schizencephalic cleft is a full-thickness path that connects two specific surfaces [1][2]:

  • The Ependyma: This is the thin “inner lining” of the brain’s ventricles (the chambers that hold brain fluid) [3].
  • The Pial Surface: This is the “outer skin” or membrane that covers the entire surface of the brain [1].

In a typical brain, these two surfaces are separated by thick layers of brain tissue. In schizencephaly, the cleft creates a bridge between them.

Open-Lip vs. Closed-Lip

Doctors categorize the cleft based on whether its walls are touching [4]:

  • Closed-Lip (Type I): The walls of the cleft are squeezed together or touching. While the path is there, there is no open space for fluid to flow through [5].
  • Open-Lip (Type II): The walls are separated, creating a visible gap. This gap is filled with cerebrospinal fluid (CSF), the clear fluid that normally cushions the brain [4][6].

Unilateral vs. Bilateral

One of the most important factors in your child’s development is how many clefts are present [7]:

  • Unilateral: A cleft is present on only one side of the brain. Children with unilateral clefts often have milder symptoms, though they may experience weakness or motor delays on the opposite side of their body [8].
  • Bilateral: Clefts are present on both the left and right sides of the brain. Bilateral clefts are more strongly associated with developmental delays, cognitive challenges, and an increased risk of epilepsy (seizure disorder) [9][10].

Associated Brain Findings

Schizencephaly rarely happens in isolation. About 50% to 90% of the time, the MRI will show other variations in brain structure [8]. Understanding these “partners” to schizencephaly helps clarify the overall picture:

Term What it Means Impact
Agenesis of the Corpus Callosum The “bridge” of nerves connecting the left and right sides of the brain is missing or partially formed [8]. Can affect how the two sides of the brain communicate, impacting coordination and complex tasks [10].
Absent Septum Pellucidum A thin, vertical membrane in the middle of the brain is missing [8]. Often found alongside schizencephaly; on its own, it may not cause symptoms, but it can be a sign of other developmental shifts [8].
Septo-Optic Dysplasia A combination of an absent septum pellucidum and small or under-developed optic (eye) nerves [8]. May affect vision or how the body regulates hormones [8].
Polymicrogyria The brain surface has “too many small folds” instead of the usual larger ones [6]. This often lines the cleft itself and is frequently linked to a higher risk of seizures [11][12].

Anatomy and Outlook

It is natural to wonder what these structural differences mean for your child’s future. While the size and type of the cleft provide a “roadmap,” they do not tell the whole story. The clinical severity—how your child actually moves, learns, and grows—is the most important measure [7]. Children with unilateral, closed-lip clefts may have very different journeys than those with bilateral, open-lip clefts, but in all cases, early support and therapy are the keys to helping the brain adapt [5][13].

Common questions in this guide

What is the difference between open-lip and closed-lip schizencephaly?
In closed-lip schizencephaly, the walls of the brain cleft are touching, leaving no open space. In open-lip schizencephaly, the walls are separated by a visible gap that fills with cerebrospinal fluid.
What does unilateral versus bilateral schizencephaly mean?
Unilateral means the cleft is only on one side of the brain, which often results in milder symptoms. Bilateral means clefts are on both the left and right sides, which is more commonly linked to developmental delays and a higher risk of seizures.
Why does my child's MRI mention polymicrogyria?
Polymicrogyria means the surface of the brain has too many small folds instead of normal, larger ones. It frequently lines the schizencephaly cleft itself and is strongly linked to a higher risk of developing seizures.
What is agenesis of the corpus callosum?
Agenesis of the corpus callosum means the nerve bridge connecting the left and right hemispheres of the brain is either missing or partially formed. This can affect how the two sides of the brain communicate, which may impact physical coordination and complex tasks.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Based on the MRI, does my child have 'open-lip' or 'closed-lip' schizencephaly, and how wide is the cleft?
  2. 2.Are the clefts unilateral or bilateral? How does the location of the cleft relate to the motor or cognitive skills we should watch for?
  3. 3.Does my child have an 'absent septum pellucidum' or 'agenesis of the corpus callosum'? How do these findings change the outlook for their development?
  4. 4.Were there any signs of 'septo-optic dysplasia,' and should we have my child's vision or hormone levels checked?
  5. 5.Is there 'polymicrogyria' lining the cleft, and does that increase the risk of seizures?

Questions For You

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References

References (13)
  1. 1

    A Rare Case of an Infant with Left Hemiparesis: A Case Report of Bilateral Open-lip Schizencephaly.

    Siti BC, Zulkifli MM, Mohd Yusoff SS, et al.

    Malaysian family physician : the official journal of the Academy of Family Physicians of Malaysia 2020; (15(3)):90-94.

    PMID: 33329869
  2. 2

    Bilateral open lip schizencephaly.

    Hakimi T, Mohammad Qasem K

    Annals of medicine and surgery (2012) 2022; (73()):103204 doi:10.1016/j.amsu.2021.103204.

    PMID: 35079358
  3. 3

    Schizencephaly: A rare cause of late-onset epilepsy in an adult.

    Laasri K, Naggar A, El Houss S, et al.

    Radiology case reports 2023; (18(11)):3861-3864 doi:10.1016/j.radcr.2023.08.014.

    PMID: 37670925
  4. 4

    Expanding Ventricular Diverticulum Overlying the Cerebral Hemisphere through an Open-Lip Schizencephalic Cleft: A Report of Two Pediatric Cases.

    Murakami N, Kurogi A, Shono T, et al.

    Pediatric neurosurgery 2024; (59(2-3)):102-108 doi:10.1159/000536188.

    PMID: 38198761
  5. 5

    Schizencephaly Associated With Bipolar Affective Disorder.

    Rama Rao R, Reddy ABS, P D, Koul A

    Cureus 2024; (16(2)):e54534 doi:10.7759/cureus.54534.

    PMID: 38516433
  6. 6

    Schizencephaly-diagnostics and clinical dilemmas.

    Halabuda A, Klasa L, Kwiatkowski S, et al.

    Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery 2015; (31(4)):551-6 doi:10.1007/s00381-015-2638-1.

    PMID: 25690450
  7. 7

    Schizencephaly in children: A single medical center retrospective study.

    Hung PC, Wang HS, Chou ML, et al.

    Pediatrics and neonatology 2018; (59(6)):573-580 doi:10.1016/j.pedneo.2018.01.009.

    PMID: 29371079
  8. 8

    Fetal MRI Findings, Etiology, and Outcome in Prenatally Diagnosed Schizencephaly.

    George E, Vassar R, Yu Y, et al.

    AJNR. American journal of neuroradiology 2025; (46(4)):800-807 doi:10.3174/ajnr.A8523.

    PMID: 39366764
  9. 9

    Epilepsy in paediatric patients with schizencephaly.

    Kopyta I, Skrzypek M, Raczkiewicz D, et al.

    Annals of agricultural and environmental medicine : AAEM 2020; (27(2)):279-283 doi:10.26444/aaem/122796.

    PMID: 32588606
  10. 10

    Schizencephaly: A Review of 734 Patients.

    Braga VL, da Costa MDS, Riera R, et al.

    Pediatric neurology 2018; (87()):23-29 doi:10.1016/j.pediatrneurol.2018.08.001.

    PMID: 30501885
  11. 11

    Cortical Clefts and Cortical Bumps: A Continuous Spectrum.

    Biswas A, Furruqh F, Thirunavukarasu S, Vivekandan R

    Journal of clinical and diagnostic research : JCDR 2016; (10(7)):TD01-2 doi:10.7860/JCDR/2016/20343.8179.

    PMID: 27630923
  12. 12

    Cortical malformations and COL4A1 mutation: Three new cases.

    Vitale G, Pichiecchio A, Ormitti F, et al.

    European journal of paediatric neurology : EJPN : official journal of the European Paediatric Neurology Society 2019; (23(3)):410-417 doi:10.1016/j.ejpn.2019.02.006.

    PMID: 30837194
  13. 13

    Open lip schizencephaly: An unusual cause of hemiparesis: A case report.

    Mequanint MB, Mengesha CA, Alemu HT, Molla YD

    Radiology case reports 2024; (19(11)):5354-5358 doi:10.1016/j.radcr.2024.07.192.

    PMID: 39280747

This page is for informational purposes only and is intended to help explain common MRI terminology. It does not replace professional medical advice. Always discuss your child's specific MRI findings and care plan with their pediatric neurologist.

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