COMPUTED TOMOGRAPHY FINDINGS IN CEREBRAL PALSY IN

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COMPUTED TOMOGRAPHY FINDINGS IN CEREBRAL PALSY IN YAOUNDE –
CAMEROON
Moifo B(1,2*), Nguefack S(3), Zeh OF(1,2), Obi FA(2), Tambe J(2), Mah E(4), Mbonda E(3),
Gonsu Fotsin J(1,2)
(1)
Radiology Department; (3)Neuropediatric Unit ; (4)Neonatalogy Unit : Yaounde Gynaeco-Obstetric and
Pediatric Hospital – PO Box : 4362 Yaounde - Cameroon
(2)
: Department of Radiology and Radiation Oncology, Faculty of Medicine and Biomedical Sciences, University
of Yaounde I
*Corresponding author
Dr Boniface MOIFO, MD
Radiology Department,
Yaounde Gynaeco-Obstetric and Pediatric Hospital
PO Box: 4362 Yaounde - Cameroon
Email: [email protected]
Phone: 00 237 77805999
ABSTRACT:
Background: Cerebral palsy is a neuro-developmental condition beginning in early childhood and
persisting throughout life. It is the leading cause of childhood disability affecting function and
development. Neuro-imaging, with magnetic resonance imaging being the chief cornerstone, plays a
vital role in determining the presence and extent of brain injury, with the possibility of determining the
age of the lesions, the prognosis and also depicting concurrent or other mimicking lesions.
Aim: To determine and describe common brain lesions of cerebral palsy patients on CT in Yaoundé
(Cameroon) where magnetic resonance imaging is still not widely available and accessible.
Materials and methods:
It was a cross-sectional descriptive study carried out at the Radiology and
Pediatric units of a university-affiliated hospital in Yaounde. Consecutive and complete records of all
patients with a clinical diagnosis of cerebral palsy who had a head CT scan performed between
September 2009 and February 2012 were reviewed.
Results: One hundred and twenty patients’ records were reviewed for the study, of which there were
66 females (sex-ratio 0.8). The mean age of the study population was 42 months with 77.4% aged 0 to
60 months. The most frequent associated clinical signs were language impairment (45.6%), mental
retardation (40.2%) and epilepsy (37.8%). Spastic quadriplegia was the most frequent (26.67%) clinical
subtype followed by spastic hemiplegia (15.83%). CT findings were observed in 90 percent of all the
scans performed. Diffuse brain atrophy (52.7%) and cerebral hypodensities (45.4%) were the most
frequent imaging findings. Atrophy was mostly cortical and sub-cortical (49.1%) while hypodensities
affected the middle cerebral artery territory in 55.1% of cases. Parenchymal calcifications were seen in
11 cases (10.2%) of which two cases of confirmed CMV infections. Brain malformations were founded
in eighth patients.
Conclusion:. Spastic quadriplegia and infantile cerebral hemiplegia were the most frequent cerebral
palsy types. Diffuse brain atrophy, and parenchymal hypodense areas constitute frequent CT findings
in patients with CP.
Keywords: Cerebral palsy, Computed tomography, Diffuse brain atrophy, Cerebral hypodensities,
Spastic quadriplegia, Infantile cerebral hemiplegia, Cameroon.
B Moifo et al
RÉSUMÉ :
Objectif. En l’absence d’IRM, décrire au scanner les principales anomalies cérébrales dans une
population d’enfants atteints de paralysie cérébrale à l’Hôpital Gynéco-Obstétrique et Pédiatrique de
Yaoundé (Cameroun).
Matériel et méthodes. Étude transversale descriptive incluant tous les enfants avec un diagnostic
clinique de paralysie cérébrale et ayant effectué un scanner cérébral entre septembre 2009 et février
2012à HGOPY.
Résultats. Cent-vingt enfants étaient inclus dont 66 filles. L'âge moyen était de 42 mois avec77,4%
d’enfants âgés de 0 à 5ans. Les troubles de langage (45,6%), le retard mental (40,2%) et l’épilepsie
(37,8%) étaient les principaux signes cliniques associés. La tétraparésie spastique était la forme la plus
fréquente (26,67%) suivie de l’hémiplégie cérébrale infantile (15,83%). Le scanner était pathologique
dans 108cas (90%). L’atrophie cérébrale (52,7%) et les hypodensités parenchymateuses (45,4%)
étaient les anomalies les plus fréquentes. L’atrophie était à prédominance cortico-sous-corticale
(49,1%) alors que les hypodensités intéressaient le territoire de l’artère cérébrale moyenne dans
55,1%. Les calcifications parenchymateuses étaient observées dans 11 cas (9,1%) dont deux cas
confirmés d’infection à CMV. Les malformations étaient associées dans huit cas (6,6%).
Conclusion. La tétraparésie spastique et l’hémiplégie cérébrale infantile étaient les formes de
paralysie cérébrale les plus fréquentes. L’atrophie cérébrale diffuse et les hypodensités constituaient
les principales anomalies scanographiques.
Mots-clés: Paralysie cérébrale, Scanner,
Hémiplégie cérébrale infantile, Cameroun.
BACKGROUND:
Cerebral palsy (CP) is defined as “a persisting
but not unchanging disorder of movement and
posture, appearing in the early years of life and
due to a non progressive disorder of the brain,
the result of interference during its
development” [1]. It describes a group of
developmental disorders of movement and
posture, causing activity restriction or
disabilities that are attributed to disturbances
occurring in the fetal or infant brain. The motor
impairment may be accompanied by a seizure
disorder and by impairment of sensation,
cognition communication and or behavior [2].
These definitions rely essentially on clinical
aspects, thus making the diagnosis of CP
clinical. There are four main clinically forms of
CP: bilateral spastic form (52%) with spastic
tetraparesis and spastic diplegia also known as
Little’s syndrome, unilateral spastic form or
infantile cerebral hemiplegia (26%), dyskinetic
or athetosic form (14%), and ataxic form (4 %)
Hypodensités
cérébrales,
Tétraparésie
spastique,
[3]. The global prevalence of cerebral palsy is
estimated at 1.5 to 2.5 per 1000, and this has
remained stable despite a marked improvement
in obstetrical methods, follow up of pregnancies
and a drop in maternal and infantile mortality
and morbidity [4-6]. In Cameroon CP represents
20.39% of Pediatric neurology consultations [7].
It is the leading cause of childhood disability
affecting function and development [8]. The
brain lesions of cerebral palsy occur from the
fetal or neonatal period to up to age 2 years.
Imaging in CP is aimed at looking for the
presence and extent of brain injury, with the
possibility of determining the age of the lesions,
the prognosis and also depicting concurrent or
other mimicking lesions. While cranial
ultrasound (US) and brain computed
tomography (CT) scans can be used in CP
imaging, magnetic resonance imaging (MRI) is
the gold standard imaging modality in the
B Moifo et al
diagnosis and in the determination of the
prognosis of patients suffering from CP.US is
the first-line imaging modality for newborns
and infant before the closure of the fontanels.
Despite radiation, CT-scan is the modality of
choice in emergency situations and in poorly
equipped areas where magnetic resonance
imaging is not available. Some studies have
been carried out in Cameroon on etiological,
clinical and therapeutic aspects of CP, without
any entirely focusing on the CT features [9, 10].
With MRI still not very accessible and available
in Cameroon, this study insists therefore on the
CT aspects of CP, with main objective to
determine and describe the most common
lesions on CT and to assess any association
between clinical type of CP and findings on CT.
MATERIALS AND METHODS:
It was a cross-sectional descriptive study carried
out at the Radiology and Pediatric units of the
Yaounde Gynaeco-obstetric and Pediatric
Hospital (YGOPH) from November 2011 to
February 2012. Complete consecutive records
of all patients with a clinical diagnosis of
cerebral palsy, who had at least a head CT
performed between September 2009 and
February 2012 were reviewed. Authorization for
the study was obtained from the institutional
authorities. Clinical information was obtained
from
the
documentation
of
pediatric
neurologists. Data was collected using a
standardized form divided into three major
sections. The first section was on basic
demographic information such as age and
gender. The second section sought for clinical
information such as signs, symptoms, CP type,
and also on the most probable etiology. The
third section investigated the various CT
findings that were depicted. CT protocol
comprised unenhanced and contrast enhanced
CT scans using a single detector CT scanner
(Neusoft, Philips 2007). Image acquisition was
spiral from the skull base to the vertex, using
3mm-thick slices. The images were reviewed on
a workstation by one radiologist. All data were
coded and entered into the statistical software
SPSS 17.0 (SPSS Inc, Chicago, USA) and
subsequently analyzed.
RESULTS:
One hundred and twenty patients were
reviewed, of which there were 66 females (sexratio 0.8; p = 0.31). The mean age of the study
population was 42 months (3.5 years). Table I
summarizes the age-group distribution of the
study population.
Table I. Age-group distribution
Age-group (years)
[0-1]
Frequency
45
Percentage (%)
38.7
]1-5]
45
38.7
]5-10]
16
11.7
Above 10
14
10.8
Total
120
100
The clinical types of CP observed are presented in
table II. Spastic quadriplegiahad the highest number
of cases (32 cases, accounting for 35.16% of
specified cases and 26.67% of all cases)
B Moifo et al
Table II. Cerebral palsy clinical types
Cerebralpalsy types
Frequency
Spastic quadriplegia
32
Spastic hemiplegia
19
15.83
20.88
Spastic diplegia
8
6.67
8.8
Dyskinetic form
4
3.33
4.4
Ataxic form
1
0.83
1.09
Mixed forms
27
22.50
29.67
Unspecified forms
29
24.17
-
Total
120
100
-
Regarding the period during which the brain assault
was supposed to have occurred, they were classified
as antenatal (15.7%), perinatal (68.4%) and
postnatal (15.7%). Other clinical signs were
associated on the CT-scans requests in CP patients:
language impairment (45.6%), mental retardation
Relative frequency
From total of 120 cases From 91 specifiedcases
26.67
35.16
40.2%), epilepsy (37.8%), microcephaly (26.1%),
and visual disturbances (19.3%). One hundred and
three head CT scans (85.7%) out of 120 were
unenhanced. Findings were observed in 108 scans
(90%) as presented in table III and Figure 1.
Table III. Cerebral palsy clinical types and CT-scans results
Cerebralpalsy types
Abnormal CT-scan findings
Normal CT-scan findings
Total
Spastic quadriplegia
30 (93,8%)
2 (6,2%)
32
Spastic hemiplegia
17 (89,5%)
2 (10,5%)
19
Spastic diplegia
7 (87,5%)
1 (12,5%)
8
Dyskinetic form
4 (100%)
0 (0%)
4
Ataxic form
0 (0%)
1 (100%)
1
Mixed forms
25 (92.6%)
2 (7.4%)
27
Unspecified forms
25 (86.2%)
4 (13.8%)
29
Total
108 (90%)
12 (10%)
120
Brain atrophy and hypodensities were the most
frequent parenchyma lesions. Atrophy was both
cortical and sub cortical in 49.1 percent (Tables
III and IV and Figure 3).
B Moifo et al
Table IV. Spectrum of CT-scan findings
CT-scan findings
Atrophy
Anoxic-ischemic-like hypodensities
Parenchyma calcifications
Malformations
Basal ganglia hypodensities
Hygroma
Tumour
Frequency
57
49
11
8
4
2
1
Percentage
52.7
45.4
10.2
7.4
3.7
1,8
0,9
Table V. Brainatrophy types
Types of atrophy
Cortical and sub cortical
Cortical
Sub cortical
Total
Frequency
28
19
10
57
Percentage (n=57)
49.1
33.3
17.6
100
Concerning the distribution of brain hypodensities with respect to arterial territories, hypodensities of
the middle cerebral artery territory were present in 34.7 percent of cases (Table V and Figure 4).
Parenchyma calcifications were seen in 11 cases of which 36.4 percent (four cases) were ependymal
calcifications with two confirmed
Table V.: Distribution of brain hypodensities with respect to the vascular territories.
Territory
Frequency
Percentage (n=49)
MCA
17
34.7
Diffused
12
24.5
ACA + MCA
10
20.4
ACA
6
12.2
PCA
2
4.1
Watershed
2
4.1
Total
49
100
ACA: anterior cerebral artery, MCA: middle cerebral artery, PCA: posterior cerebral artery
B Moifo et al
Table VI. Brain malformations in cerebral palsy patients.
Types
Pachygyria
Lissencephaly
Corpus callosum agenesis
Vermis agenesis
Dandy Walker syndrome
Total
Frequency
2
2
2
1
1
8
Fig1. Spastic quadriplegiain a 7-month-old girl
(1a): diffuse cortical and subcortical hypodensities with areas of
porencephaly
(multicystic encephalopathy). Spastic hemiplegia in
.
an 18-month-old boy
(1b): cortical and subcortical left parietal hypodensities, posterior
periventricular hypodensity and ventricular septum agenesis
Fig3. Spastic quadriplegia in 4-year-old girl (3a): diffuse
cortical and sub-cortical atrophy with ventricular and subarachnoïdian spaces expansion. Spastic hemiplegia in 5-yearold girl (3b): diffuse cortical and sub-cortical right cerebral
atrophy with enlarged right ventricle. Spastic diplegic CP in
24-month-old boy (3c): diffuse frontal and parietal cortical
atrophy with sub-arachnoïd spaces expansion. Spastic
tetraplegic CP in 3.5-year-old boy (3d): diffuse sub-cortical
hypodensities and atrophy predominantly on the frontal lobes.
Percentage (n=8)
25
25
25
12.5
12.5
100
Fig2. Spastic diplegic CP in 8-month-old boy
(2a): diffuse frontal cortical and subcortical homogeneous
hypodensities. Mixed form of CP in a 24-month-old girl
(2b): Cortical and sub-cortical brain hypodensities
predominantly on the left parietal lobe.
Fig4.Spastic quadriplegiain 2-month-old boy (4a):
diffuse cortical and sub-cortical hypodensities
(multicystic encephalopathy) with diffuse brain atrophy.
Bilateral frontal porencephalic hypodensities in 8-yearold girl (4b) with CP. Cortical and sub-cortical occipital
hypodensities in 11-year-old girl (4c) with CP. Bilateral
parietal sub-cortical hypodensities in 10-year-old boy
(4d) with CP.
B Moifo et al
Fig 5.CP in 3-month-old boy
(5a) craniosynostosis. Pachygyria in a 4-year-old
male (5b) with CP. Cortical, sub-cortical and
subependymal calcifications in 1-month-old girl
(5c) with CP and proved CMV infection. Frontal
atrophy and corpus callosum agenesis in 2-yearold male
(5d) with CP.
DISCUSSION: The most frequent clinical
signs in CP patients were language impairment
(45.6%), mental retardation (40.2%) and
epilepsy (37.8%). Spastic quadriplegia was the
most frequent (26.67%) clinical subtype
followed by spastic hemiplegia (15.83%). CT
findings were observed in 90% of all the scans
performed. Diffuse brain atrophy (52.7%) and
cerebral hypodensities (45.4%) were the most
frequent imaging findings. Parenchymal
calcifications were present in 11 cases and brain
malformations in eighth patients. There was no
sex predilection in the occurrence of cerebral
palsy in this study. However, Johnston and
Hagberg [11] suggested that sex hormones seem
to protect the female fetal brain from anoxia and
ischemia and hence would be less predisposed
to cerebral palsy compared to the males.
Mbonda et al [7], Karumuna and Mgone [12]
found a sex ratio of 1.3 in favour of males,
while Ndiaye et al [13] found a sex ratio of 1.44
in favourof males. Stanley et al [14] suggested
that lower socioeconomic status and male sex
may increase risk factors for cerebral palsy.
Most of the patients with clinical suspicion of
cerebral palsy in this study were aged between 1
month and 5 years old (77.4%). This is in line
with what the literature suggests, on the average
period for clinical diagnosis and the
establishment of a possible prognosis [13, 15].
At 1 year, the brain structure is well developed
to permit more precise clinical manifestations
and diagnosis and at 1.5 years a notion on the
evolution of the condition can be obtained and
consequently on the outcome or prognosis. Most
of the brain insult was likely to occur during the
perinatal period. Previous studies have shown
that neonatal asphyxia and antenatal infections
are responsible for most cases of cerebral palsy
[7, 13, 16]. The insult that gives rise to cerebral
palsy
occurs
during
immature
brain
development. According to most references [8],
this initiating event can take place anytime
between prenatal development and age 2 years.
However, children are usually not diagnosed
until after age 1 year, with the condition
becoming identifiable as children fail to meet
developmental
milestones.
The
higher
frequency of spastic forms may be due to the
fact that the clinical type of CP was not
specified in 24.17% (29 of 120 cases). In
Mbonda et al study [7], spastic forms accounted
for 57.8% while 38.1% of cases were mixed
cases, and in Ndiaye et al study, accounted for
49% with 26.5% spastic quadriplegia [13]. In
the study carried out by Kolawole et al, the
spastic forms were responsible for 83 % positive
yields on CT [15]. Spastic cerebral palsy, due
to cortex/pyramidal tract lesions, is the most
common type and accounts for approximately
80% of cases [8, 14]. This type of cerebral palsy
is characterized by spasticity (velocity
dependent increase in tone), hyperreflexia,
clonus, and an upgoing Babinski reflex.
Extrapyramidal or dyskinetic cerebral palsy
(athetoid, choreoathetoid, and dystonic)
comprises 10-15% of this disorder and is
characterized more by abnormal involuntary
movements. Ataxic cerebral palsy comprises
less than 5% of cerebral palsy. The prevalence
of CP subtypes varied from one study to another
[3, 7, 8, 11, 13, 14]. According to Bax et al [3],
clinical factors correlate with CP are
prematureness (45.2%), infections during
pregnancy (39.5%) and multiple pregnancy
(12%). In our setting, brain assault was
supposed to have occurred in perinatal period in
68.4% with asphyxias and antenatal infections
identified as leading risk factors, and anoxicischemic-like hypodensities counting for 45.4%
of CT-scan anomalies. A study on epilepsy in
children with cerebral palsy by Mbonda et al.
also showed neonatal asphyxia and infections to
be the most frequent risk factors for CP [7].
Gururaj et al. also found neonatal hypoxia
responsible for 60% of cerebral palsy and
seizures [16]. With respect to CT technique, 86
% of the scans were not contrast-enhanced.
Neuroimaging of CP with computed
tomography does not usually require contrast
enhancement. Contrast can be used more to
exclude other entities that are not part of the
syndrome that may enhance like tumors and
infections. In our study the positive yield of CT
was high (90%). This is an encouragement for
settings with at best CT as modality for
neuroimaging. This high positive yield of CT
scans in CP is comparable to that observed by
Kolawole et al. who recorded a 72.5 % yield
[15]. Diffuse brain atrophy (52.7%) and
parenchymal hypodense areas (45.4%) were the
most frequent CT findings. Atrophic changes
had been earlier reported to be the commonest
CT findings in cerebral palsy accounting for
30.8% to 54.4% [7, 13, 15]. This brain
parenchyma reduction can be explained by
neuronal destruction from anoxo-ischemic
lesions and infections. Bax et al [3] with MRIscans observed that white-matter damage of
immaturity,including..periventricular
leukomalacia was the most common finding
(42.5%), followed by basal ganglia lesions
(12.8%), cortical/subcortical lesions (9.4%),
malformations (9.1%) and focal infarcts
(7.4%)and that there are good correlations
between the MRI and clinical findings. Brain
hypodensities were mostly (55.1%) on the
middle and/or anterior cerebral arteries
territories. MRI is the modality of choice to
differentiate white matter lesions from cortical
lesion, and to diagnose basal ganglia lesions and
periventricular leukomalacia[3]. Some negative
CT cases may be positive on MRI. Importantly
also some brain malformations were observed.
These could be considered as differential
diagnoses for the clinical manifestations that
were initially attributed to be due to cerebral
palsy. In CP the extent and topography of
lesions determine the clinical type of motor
impairment (unilateral or bilateral spastic forms,
ataxic and dystonic forms) and the frequency
and severity of associated impairments [3,
17].The white matter lesions are more frequent,
especially with prematureness and bilateral
spastic forms, dyskinetic or ataxic forms. In
children born at term, cortical lesions and the
basal ganglia lesions are more common in
unilateral forms or dyskinetic forms. 10% of CP
are linked to a brain malformation. There are
usually subtle lesions especially in the basal
ganglia that can be missed on CT-scan and even
on MRI[17]. Limitations to the study were
largely due to retrospective data collection, as
many cases were not classified clinically.
CONCLUSION:
Spastic quadriplegia and infantile cerebral
hemiplegia were the most frequent cerebral
palsy types. Diffuse brain atrophy, and
parenchymal hypodense areas constitute
frequent CT findings in our patients with CP.
With a high CT positive yield, CT then remains
useful in the screening of patients with cerebral
palsy in developing countries where magnetic
resonance imaging is still relatively unavailable
B Moifo et al
and inaccessible. Cranio-cerebral malformations
should be given some consideration prior to the
workup for cerebral palsy.
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