CONTRIBUTION OF MRI IN THE EXPLORATION OF CHILDREN HYPOPITUITARISM

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CONTRIBUTION OF MRI IN THE EXPLORATION OF
CHILDRENHYPOPITUITARISM
5th Arab Radiological Congress of the Pan Arab
Association of Radiological

• M. ALOUI, N. AIDI, W. DOUIRA-KHOMSI, A. EL
  GHAZALY, H. LOUATI, L. BEN HASSINE, L. LAHMAR,
  I. BELLAGHA Department of Pediatric Radiology,
  Bechir Hamza childrens Hospital

Hammamet, 26-28 April 2012
PED1
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Introduction

• Hypopituitarism refers to the absence or
  reduction in function of hormones produced by the
  pituitary gland
• It may be idiopathic or associated with organic
  causes, such as tumor, surgery, or irradiation of
  the sellar area
• Early diagnosis and treatment promote the best
  possible outcomes
• Magnetic resonance imaging (MRI) retains an
  important place in the diagnostic and therapeutic
  approach of hypopituitarism

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Objectives

• Illustrate through 14 observations, the
  contribution of MRI in the exploration of
  children pituitary insufficiency
• Review the role of MRI in the morphological
  exploration of the sellar region and the
  detection of the associated brain damage

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PATIENTS AND METHODS 

• Retrospective study involved 14 children
  monitored for non tumoral-hypopituitarism
  including 13 with clinical growth retardation and
  one with hypogonadism. All of them have a
  pituitary MRI
• Patients were admitted to this study only if MRI
  revealed anterior pituitary hypoplasia

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PATIENTS AND METHODS 

• Technique
• MR studies were performed with a 1.5-T (GE
  Medical System)
• All patients were explored with the same protocol
  at the level of the pituitary
• Sagittal and coronal T1-weighted spin echo images
  
• Sagittal or coronal T2-weighted fast spin echo
  images
• T1-weighted sequences after intra venous
  administration of contrast agent if pituitary
  stalk was not seen

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PATIENTS AND METHODS 

• The height of the pituitary gland was determined
  on the midsagittal T1-weighted image by measuring
  the greatest distance between the base and the
  top of the gland
• Pituitary height measurements were compared with
  published normal values for age
• A pituitary was considered to be hypoplasic when
  the gland height was less than -2 SD for age

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Results 

• Age range 2 to 17 years (at the time of MRI)
• Sex 8 males, 6 females
• Absence of family history of hypopituitarism for
  all patients
• Hormonal assessment
• Isolated Growth hormone deficiency (IGHD) in 8
  cases
• Multiple pituitary hormone deficiencies (MPHD)
  in 2 cases
• Was not realized in 4 cases

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RESULTS

• MRI performed showed
• Pituitary hypoplasia in all patients
• Combination with other types of brain damage in 8
  cases specified as shown
• Disruption of the pituitary stalk in 3 cases (2
  with MPHD and 1 without hormonal assessment)
• Ectopic posterior pituitary in 3 cases
• Chiari I malformation in 1 case
• Small size of the corpus callosum with arachnoid
  cyst in 1 case

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RESULTS
Fig. 1 17-year-old boy with growth and
pubertal failure MRI midsagittal T2 and
T1-weighted images, midsagittal and coronal
T1-weighted enhancement images show a small
anterior pituitary gland (2.8 mm height) (red
arrow). Posterior pituitary (yellow arrow) and
stalk (green arrow) are normal
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RESULTS
Fig. 2 8-year-old girl with growth failure
MRI coronal and midsagittal T1-weighted images
show a small anterior pituitary (2.4 mm height)
(yellow arrow) and an ectopic posterior pituitary
(orange arrow) seen as an area of high signal
intensity in place of the pituitary stalk which
is not visible
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RESULTS
A
Fig. 3 9-year-old boy with growth failure
MRI coronal T2-weighted and midsagittal
T1-weighted images show a small anterior
pituitary (2.5 mm height) (yellow arrow) and
Chiari I malformation (orange arrow). Sagittal
T2-weighted MR medular image was normal
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RESULTS
Fig. 4 9-year-old boy with hypogonadism and a
MPHD in the hormonal assessment MRI unenhanced
midline sagittal T1 and enhanced coronal
T1-weighted images show a small anterior
pituitary (3 mm height) (yellow arrow), ectopic
posterior pituitary seen as an area of high
signal intensity in the midline at the median
eminence (orange arrow). The thin stalk is only
seen after injection of gadolinium (green arrow)
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RESULTS
B
Fig. 5 3-year-old boy with facial dysmorphism
and growth failure MRI midsagittal T1-weighted
and coronal T2-weighted images show small
anterior pituitary gland (1.9 mm height) (yellow
arrow), small size of the corpus callosum (green
arrow) and temporal arachnoid cyst (orange
arrow)
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DISCUSSION

• Childhood hypopituitarism may be present at birth
  or may be acquired
• In childhood hypopituitarism, GH is the most
  commonly underproduced pituitary hormone
• The diagnosis of hypopituitarism must integrate
  clinical data and appropriate hormonal testing
• Once the diagnosis of hypopituitarism has been
  made a head MRI scan must be performed to look
  for a possible organic or structural basis

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DISCUSSION

• Laboratory diagnosis is not always easy, the IGHD
  may be transitory ? MRI occurs early in the
  diagnostic strategy, often before laboratory
  confirmation of the pituitary  deficiency
• MRI can be used to study the anatomic details of
  the pituitary-hypothalamic region
• The prevalence of morphologic abnormalities in
  the pituitary gland is greater in patients with
  combined pituitary hormone deficiency than in
  those with IGHD

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DISCUSSION

• Hypopituitarism can be classified in two groups
• Congenital Hypopituitarism
• Features hypoglycemia / small penis at birth/
  noninfectious form of hepatitis
• Causes birth trauma and/ or asphyxia as part of
  one of a number of midline anatomical defects /
  genetic mutation
• A congenital basis is strongly suggested by the
  presence of a transected pituitary stalk on MRI

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DISCUSSION

• Acquired Hypopituitarism
• Causes
• Tumor The most common tumor in this region in
  childhood is craniopharyngioma
• Radiation treatment of a cancerous tumor in the
  head or neck region
• Other causes brain infection (encephalitis and/
  or meningitis), hydrocephalus (even without an
  underlying tumor), vascular abnormalities and
  major head trauma

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DISCUSSION

• Abnormalities that can be associated with
  congenital hypopituitarism include
• A small pituitary gland with filling of the sella
  with cerebrospinal fluid (empty sella)
• Ectopic posterior pituitary gland
• Pituitary stalk transection syndrome (lack of
  pituitary stalk visibility, hypoplasia of the
  anterior hypophysis, ectopic posterior pituitary
  gland)
• Small optic nerves, hydrocephalus, vascular
  abnormalities
• Midline CNS malformations (optic nerve
  hypoplasia, Chiari malformation, absence of the
  septum pellucidum and/ or the corpus callosum)

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DISCUSSION

• Diagnosis of tumor in the hypothalamic-pituitary
  area (craniopharyngioma)
• Lateral skull-ray erosion of the normal sellar
  architecture and/ or the presence of suprasellar
  calcification
• MRI show mixture of solid and cystic components
  and may contain a ring of calcification around a
  cystic component

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DISCUSSION

• Pituitary function was more severely impaired in
  the patients with pituitary stalk interruption
  syndrome (MPHD)
• In contrast, in the patients with isolated
  pituitary hypoplasia, GH secretion was less
  severely impaired (IGHD)
• ? Correlation between the morphology of
  the hypothalamic-pituitary axis
  and endocrine disease severity
• ? T1 weighted sequences are the cornerstone of
  the morphological analysis of the pituitary
• ? The injection of gadolinium is more
  sensitive to visualize the pituitary stalk when
  it is not seen before injection

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DISCUSSION

• Treatment of Hypopituitarism
• If an underlying cause is discovered on the MRI
  of the head, such as a tumor and/ or
  hydrocephalus, appropriate neurosurgical
  intervention is required
• Identified hormone abnormalities require
  treatment with appropriate hormonal replacement
  therapies

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CONCLUSION

• Non-tumor etiology constitutes a major group of
  childhood hypopituitarism
• MRI abnormalities correlated with the severity of
  growth hormone deficiency
• These abnormalities are more prevalent in
  patients with MPHD than in IGHD
• The presence of anterior pituitary hypoplasia
  should alert the radiologist to the possibility
  of associated cerebral malformations

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