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Abstract
To assess the effectiveness of MRI in identifying the
spectrum of corpus callosum anomalies in epileptic
paediatric patients, a descriptive case series was studied in
the General Paediatric Hospital, Baghdad from March 2017
to March 2020.A total of 52 patients with ages ranging from
4 months to 14 years were included. The Imaging criteria
included MRI evaluation showing spectrum of anomalies
involving the corpus callosum with malformation of cortical
development, lipoma, Dandy Walker syndrome and Chiari
malformation. Demographic data was recorded. The study
included 52 patients with ages ranging from 4 months to 14
years, (mean age 5.94 ± 4.08 years). There were 31(59.7 %)
males and 21(40.3%) females diagnosed as 34(65%)
agenesis, 25(48%) partial agenesis, 9(17.3%) complete
agenesis and 18(34.7%) hypoplasia of corpus callosum.
Other malformations noted in 32 patients included, Chiari
malformation, cortical neuromigration disorders, Dandy
Walker malformation, lipoma, cerebellar hypoplasia,
posterior fossa arachnoid cyst and Chiari 2 malformation.
Imaging evaluation in epilepsies, effectively detects callosal
disorders and associated malformations, which add
valuable data improving clinical management, seizure
control clinical management and further decision-making.
Keywords: corpus callosum, anomalies, epilepsy, MRI
Introduction
The corpus callosum (CC) is a midline cerebral white matter
structure, which represents the largest forebrain
commissure of tightly packed tracts in the central nervous
system, connecting the two cerebral hemispheres. It
comprises of four parts, rostrum, genu, body and splenium.
It is formed from anterior to posterior, beginning with the
genu at 12th weeks gestation. The rostrum is an exception,
as it develops last at 18-20 weeks.1-3 If the Corpus callosum
does not form prior to birth, it will never form. If there are
some corpus callosum nerves crossing between the
hemispheres at birth, these may continue to develop, but
new nerves or fibers will not develop. Since agenesis of CC
is congenital, all the rest of the brain connections are
organized accordingly.4 Congenital callosal malformations
range from agenesis, hypogenesis or hypoplasia (complete
CC but thin). The Callosal hypogenesis (partial absence) is
associated with other cerebral malformations, such as
migration disorders, Dandy Walker etc.5,6 Abnormal
imaging findings can be seen in a person with epilepsy.5
Thus neuroimaging has an important application in the
diagnosis and treatment. Computed tomography,
combined with EEG recording which has an essential role in
confirming the clinical diagnosis, represent the standard
clinical practice for a child with recurrent seizures.7,8
Computed tomography is important for the diagnosis of
CC lipoma, and other acquired pathologies with
calcifications or haematomas' involving the anterior part.9
Agenesis of the corpus callosum is one of the most
frequent malformations in the brain with a reported
incidence ranging between 0.5 to 70 in 10000.10 Disorders
of the CC may be caused by arrested growth, or delayed
development that attempts to compensate for earlier
abnormalities in the evolution of midline structures. It can
also be observed in association with major malformations
of the embryonic forebrain prior to formation of the anlage
of the corpus callosum e.g., holoprosencephaly.2,11
Currently, MRI which is safe and painless, is the imaging
procedure of choice in infants and children. It is
recommended in the evaluation of cerebral pathologies
and is used in evaluating agenesis of CC, even in patients
who have previously undergone CT scan and ultra-
sonography examination. The Multiplanner capability and,
high soft tissue contrast permits confident diagnosis of
agenesis of corpus callosum and its associated anomalies
especially neuronal migration anomalies or atypical form of
holoprosencephaly.12-14 Magnetic resonance Imaging
defines CNS anatomy in detail, permits in-vivo
characterization of human brain anomalies, previously
incompletely evaluated using CT scan and
ultrasonography. Certain anomalies, previously thought to
be isolated, have proven to be associated with one or more
brain malformations. Thus, MRI sheds new light on a
fundamental problem in clinical neuroradiology.15 Corpus
callosum and other interhemispheric connections are
considered to transfer unilateral abnormal electrical
activities to the contra lateral hemisphere.
Vol. 71, No. 12 (Suppl. 8), December 2021
S-190 15th Annual Conference of the College of Medicine, Mustansiriyah University, Baghdad
Department of Pediatrics, College of Medicine, Mustansiriyah University,
Baghdad, Iraq.
Correspondence: Email: dr.muna.zghair@gmail.com
CASE SERIES
Corpus callosum disorders and associated malformations in paediatric epilepsy:
MRI analytic study
Muna Abdul Ghani Zghair
Magnetic resonance imaging mapping, confirms the
genu of corpus callosum, as the major pathway for
seizures generalization.16 This study aimed to verify the
role of MRI in the diagnosis of callosal disorders among
epileptic patients in the paediatric age group.
Methods
A descriptive case series on 52 patients was conducted in
the radiology department MRI unit, of a major tertiary
paediatric health care center (Central Teaching Hospital of
Paediatrics'), Baghdad, Iraq, from March 2015 to April 2020.
It was an observational study including 52 patients. The
Ethical Committee of the Medical College and Central
Teaching Hospital of Paediatrics approved the study.
Included were 31 males and 21 females with age ranging
from 4 months to 14 years. The decision to perform MRI
was based on the clinical judgment of the referring
paediatric neurologist. All patients included had history of
seizures. Demographic criteria collected were age and
gender, Imaging of corpus callosum with associated
disorders, types, severity and malformations.
Measurements were taken at the mid sagittal plain view
which clearly defined the four callosal components,
rostrum, genu, body, and splenium. Axial plain showed
parallel configuration of the lateral ventricles, coronal
plains showed midline defects associated with Lipoma, and
listhencephaly. Patients were divided according to age (4
months -1 year), (2-5 years) and (6- 14 years). Imaging
criteria were based on the identification of complete ACC,
partial ACC, hypogenesis, and associated malformations of
cortical development, ventricles, posterior fossa and extra-
axial spaces. This was a native study without intravenous
contrast media as the contrast does not provide a further
diagnostic value. Utilizing MRI machine with 1.5 Tesla
MEGNATOM Avanto scanner (Siemens, Germany) was
employed. Using head coil, with T1, T2, FLAIR and diffusion
weighted sequences, with the required plains, sagittal, axial
and coronal plains, the corpus callosum appeared as high
signal on T1, low signal in T2 and intermediate signal on
FLAIR sequences. The duration of each examination lasted
about 20 minutes. General anaesthesia was recommended
for children under 6 years age and in the older non-
cooperative or nervous children. In older children, the
examination was explained to both the patient and
relatives, to relieve anxiety. Our centre permits the stay of
parents in the MRI examination room throughout the test.
The exclusion criteria were, patients with history of
preterm delivery, infectious, ischaemic, haemorrhagic,
traumatic, tumoural, iatrogenic and toxic cerebral
pathologies. The Center's traditional workup excluded
neonates and infants less than 4 months' age to avoid the
vulnerable potential hazards of electromagnetic field
effect, physiological instability and sedation. Patients with
inadequate scan quality were also excluded. In these
patients, Computed tomography replaced MRI.
Data were collected, summarized, analyzed and presented
using Statistical package of Microsoft office Excel 2010.
The results of data analysis was presented as mean with
standard deviation and ranges to determine the number
and percentages (%) per hundred using one sample with a
descriptive, quantitative, observational and exploratory
analysis design.
Results
The study group comprised of 52 paediatric patients, of
various callosal disorders and associated anomalies. The
age range of the children was from 4 months to 14 years,
with a mean age of 5.94 ± 4.08 years. All patients selected
had a history of full term delivery. These results are
summarized in Table-1. Magnetic resonance imaging
findings of corpus callosum disorders showed, complete
agenesis, partial agenesis and hypoplasia representing
9(17.3%), 25(48%) and 18(34%) cases respectively.
Associated malformations contributed to 32(62%) cases.
Hypoplastic extra colossal and supra tentorial white
J Pak Med Assoc (Suppl. 8)
15th Annual Conference of the College of Medicine, Mustansiriyah University, Baghdad S-191
Figure-1: Associated congenital anomalies.
matter was a constant observation in the entire study
group. Pachygyra and Dandy Walker syndrome were the
more frequent associated malformations, being 10 (19.2%)
and 6 (11.2%) respectively. There was non-specific age or
gender distribution of isolated callosal disorders. About
one-half of female patients presented with imaging
features of both callosal disorders and malformation.
Seventy percent of epileptic male patients had callosal
disorders and additional malformations. Table-1 shows
the maximum age distribution in the category of 2-5
years. Male gender was more effected, 31 (59.7 %) with
partial agenesis in 25 (48%).
Figure-1 displays the associated malformations, with
Pachygyra (30.1 %) being more frequent.
Figure-2 displays the mid sagittal FLAIR sequence
showing complete absence of corpus callosum with
Pachygyra, involving frontal parietal and occipital lobes.
Discussion
Agenesis of the corpus callosum is an abnormal
developmental malformation involving the white matter
commissural fibers. It represents the largest intra cerebral
connecting white matter bands, between the two
hemispheres of the cerebrum. Callosal disorder
involvement could be in various forms, complete absence
(agenesis), partial agenesis, when the missing component
involves one of the portions, genu, body, splenium or the
rostrum or is hypo-plastic, when corpus callosum is
present without a missing segment but thin or smaller
than normal. These abnormalities are diagnosed by
various neuro-imaging modalities, Ultrasonography, CT
scan and MRI. MRI is the imaging investigation of choice
in these circumstances. It utilizes a non-ionizing radiation
device, providing an excellent intrinsic soft tissue contrast
discrimination with Multiplanner facilities along with
providing more comprehensive, additional information
which aids in the diagnosis. Nevertheless, it is time
consuming with most paediatric patients requiring
sedation or general anaesthesia. The specific selection of
paediatric patients presenting with epilepsy in the current
study was observed as it is the most common clinical
association with corpus callosum disorders. In the clinical
description of Marie-Laure Moutard, the author describes
epilepsy in 50 % of patients presenting with agenesis of
corpus callosum.17 Neonatal and prenatal imaging studies
suggest that corpus callosum agenesis occurs in at least
1:4000 live births.18 Abnormalities of corpus callosum was
almost always accompanied by other brain
malformations and grey matter heterotopia was the most
common malformation of cortical development.15 In the
current series, 32 of the 52 patients presented with
associated brain malformations. This makes a figure of
61.6%. The types of individual, accompanied
malformations in our study differ with Dandy Walker
syndrome, and pachygyra being the most common
malformations. Interhemispheric cysts and lipoma were
present in 15 patients. In this study, we also found two
patients with lipoma and one patient with listhencephaly.
The difference in data observation between our study and
others,15,17 is related to the inclusion of variable clinical
CNS and somatic manifestations in multicentre studies.
This will offer a large sample size and more generalizable
MRI findings. Enrolling asymptomatic individuals with
callosal disorders, with a wider age range, based on
retrospective data collection from the database network
can raise a doubt on the frequency of the corpus callosum
disorders. This study describes the MRI findings of a single
tertiary centre on selected symptomatic paediatric
Vol. 71, No. 12 (Suppl. 8), December 2021
S-192 15th Annual Conference of the College of Medicine, Mustansiriyah University, Baghdad
Table-1: Findings of MRI in corpus callosum defects in relation to age and gender.
Variable No. %
Age (years) 0-2 13 25
2-5 18 34.6
5-10 11 21.2
10-15 10 19.2
Gender Female 21 40.3
Male 31 59.7
Types of Corpus Collosum Defect Agenesis 9 17.3
Partial 25 48
Hypoplastic 18 34.7
Associated Anomalies Multiple anomalies 12
single anomaly 20 32 62
Figure-2: a) T1-weighted Spin echo sagittal plane MRI. Total absence of corpus callosum,
cerebellar hypoplasia, frontotemporal Pachygyra and Semi lobar holoprosencephaly. b)
Bilateral semi lobar holoprosencephaly and cerebellar hypoplasia.
patients who presented with epilepsy, with a limited age
range showing MRI imaging criteria pointing to
congenital anomalies. This represents a superior inclusion
criterion. The other factor is the choice of a single centre
work up approach, might increase the risk of bias which
can modify the results. However, child epilepsy is a critical
care emergency situation. A single centre study provides
more effective treatment estimates, with a closer follow
up observation than a multicentre trial. Extra-callosal,
supra-tentorial reduced white matter volume was a
constant observation in all cases included in our study.
This is in agreement with other studies, as the corpus
callosum is the principle transverse white matter tract
connecting the cerebral hemispheres.15 In the current
series, agenesis and hypoplastic corpus callosum is more
in boys than girls which is a similar observation in the
literature.12,19 Imaging MRI observation of Partial callosal
agenesis is the most common feature, followed by
callosal hypoplasia and complete agenesis. This is in
accordance with the studies published by Barkovich et.al
and Essam et al.1,20
Conclusion
Magnetic resonance imaging is a unique neuro-
radiological imaging technique in confirming the
detection of corpus callosum disorders, midline structures
and associated malformations. The standard mid sagittal
and coronal sectional plains, confidently provide a high
diagnostic performance, which allows, correct diagnosis,
decision making and subsequent management.
Acknowledgement: The help by Dr. Ahlam Mohamad
Albojassim, C.A.B.P/ pediatrics is gratefully
acknowledged.
Disclaimer: None.
Conflicts of Interest: None.
Source of Support: Al Mustansiriryah University College
of Medicine, Baghdad, Iraq.
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15th Annual Conference of the College of Medicine, Mustansiriyah University, Baghdad S-193
