1. CONTRIBUTION OF MRI IN THE EXPLORATION OF CHILDREN HYPOPITUITARISM
5th Arab Radiological Congress of the Pan Arab Association of Radiological
CONTRIBUTION OF MRI IN THE EXPLORATION OF CHILDREN HYPOPITUITARISM
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 children’s Hospital
Hammamet, April 2012
PED1

2. 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

3. 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

4. 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

5. MR studies were performed with a 1.5-T (GE Medical System)
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

6. 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 6

7. 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

8. Pituitary hypoplasia in all patients
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

9. 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

10. 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

11. 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

12. 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)

13. 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)

14. 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

15. 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

16. Hypopituitarism can be classified in two groups
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

17. Acquired Hypopituitarism Causes
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

18. 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)

19. 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

20. 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

21. Treatment of Hypopituitarism
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

22. 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

23. REFERENCES
J. Hamilton, S. Blaser, D. Daneman. MR Imaging in Idiopathic Growth Hormone Deficiency. AJNR 1998; 19:1609–1615.
P. Dutta, A. Bhansali, P. Singh, R. Rajput, S. Bhadada. Clinico-Radiological Correlation in Childhood Hypopituitarism. Indian Pediatrics 2010; 47: 17.
S. Falcone, J. Sanchez, RM. Quencer. Lack of Normal MR Enhancement of the Pituitary Gland: Findings in Three Siblings with Combined Pituitary Hormone Deficiency. AJNR 1998; 19: 287–289.
T. Arrigo, F. De Luca and al. Relationships between neuroradiological and clinical features in apparently idiopathic hypopituitarism. European Journal of Endocrinology 1998; 139: 84–88.
Van der Linden, Hendrik W. van Es. Pituitary Stalk Transection Syndrome with Ectopic Posterior Pituitary Gland. Radiology 2007; 243: 2.