4. Dr Ahmed Esawy
the hypothalamus is a portion of the brain that
contains a number of small nuclei with a variety of
functions.
One of the most important functions of the
hypothalamus is to link the nervous system to
the endocrine system via the pituitary
gland (hypophysis).
The hypothalamus is located below the thalamus, just
above the brainstem and is part of the limbic system
5. Dr Ahmed Esawy
The hypothalamus is involved in the following
control systems:
• body temperature
• autonomic nervous system
• emotional and food behavior
• endocrine (via the pituitary)
• circadian rhythm.
6. Dr Ahmed Esawy
The hypothalamus is a portion of the brain near the third
ventricle, located below the thalamus and above the
brainstem.
The anterior boundary of the hypothalamus is determined by
the line connecting, the lamina terminalis and the optic chiasm
at its lower border and the anterior commissure above .
The lower limit of the hypothalamus is formed by the
infundibulum, the tuber cinerum and the mamillary bodies
(from front to back ).
superior: an imaginary line drawn between the anterior and
posterior commissures
The posterior limit is represented by a straight line joining the
mamillary bodies and the posterior commissure.
7. Dr Ahmed Esawy
(a) Drawing shows the hypothalamus (outlined with a dashed line) below an imaginary
line between the anterior commissure (AC) and the posterior commissure (PC).
The anterior boundary of the hypothalamus is the lamina terminalis (LT), which extends
between the optic chiasm (OC) and the anterior commissure.
The posterior boundary is imprecise; it is indicated by a line that extends between the
mamillary bodies (MB) and the posterior commissure.
The floor of the hypothalamus is formed by the infundibular stalk (IS), the tuber cinereum
(TC), and the mamillary bodies.
The major tracts related to the hypothalamus, the mamillothalamic tract (MT) and the
postcommissural fornix (PF), are also shown.
8. Dr Ahmed Esawy
(c) On a sagittal contrast material–enhanced MR image,the infundibular stalk and
pituitary gland show normal homogeneous enhancement, which reflects their lack of a
blood-brain barrier
10. Dr Ahmed Esawy
(b) Sagittal T1-weighted MR image clearly demonstrates the anatomy of the
hypothalamus. Note the high-signal-intensity area (arrowhead) representing the
posterior pituitary gland.
AC anterior commissure, IS infundibular stalk, LT lamina terminalis, MB mamillary
bodies, OC optic chiasm, PC posterior commissure, TC tuber cinereum.
11. Dr Ahmed Esawy
MRI of the Brain (hypothalamus):
T1-weighted sagittal cut. .
1, Anterior commissure.
2, Corpus callosum.
3, Third ventricle.
4, Cerebellum.
5, Pons.
6, Pituitary gland.
12. Dr Ahmed Esawy
(a) median eminence (b), mamillary bodies
The major hypothalamic tracts and nuclei (circled) are arranged symmetrically about the
floor and lower medial surface of the third ventricle and include the arcuate nucleus
A), anterior commissure(AC), dorsomedial nucleus (DM), lateral nucleus (L),
lateral preoptic nucleus(LPO), mamillary bodies(MB), medial preoptic nucleus(MPO)
posterior nucleus (P), paraventricular nucleus (PV), suprachiasmatic nucleus (SC),
supraoptic nucleus (SO), and ventromedial nucleus (VM).
The arcuate nucleus is located at the base of the infundibulum. F fornix, ME median
eminence, MT mamillothalamic tract, OC optic chiasm, OT optic tract
Coronal T1-weighted MR images obtained at the level of (from rostral to caudal) the
optic chiasm
13. Dr Ahmed Esawy
Coronal T1-weighted MR images obtained at the level of (from rostral to caudal) the optic
chiasm
(c) show the various hypothalamic structures
lateral nucleus (L), F fornix, mamillary bodies(MB), MT mamillothalamic
, posterior nucleus (P), paraventricular nucleus (PV)
14. Dr Ahmed Esawy
MRI of the Brain (hypothalamus):
T1-weighted axial cut. .
1, Anterior commissure.
2, Putamen.
3, Third ventricle.
4, Corpus callosum.
15. Dr Ahmed Esawy
MRI of the Brain (hypothalamus):
T1-weighted coronal cut. .
1, Anterior commissure.
2, Caudate nucleus.
3, Corpus callosum.
4, Lateral ventricle.
5, Third ventricle.
16. Dr Ahmed Esawy
MRI of the Brain (hypothalamus):
T1-weighted axial cut. .
1, Infudibulum.
2, Cerebral aqueduct.
3, Midbrain.
4, Substantia nigra.
17. Dr Ahmed Esawy
MRI of the Brain (hypothalamus):
T1-weighted coronal cut. Image .
1, Infudibulum.
2, Caudate nucleus.
3, Corpus callosum.
4, Lateral ventricle.
5, Pituitary gland.
18. Dr Ahmed Esawy
MRI of the Brain (hypothalamus):
T1-weighted sagittal cut. Image .
1, Mammillary body.
2, Corpus callosum.
3, Third ventricle.
4, Cerebellum.
5, Midbrain.
6, Pons.
7, Pituitary gland.
19. Dr Ahmed Esawy
MRI of the Brain (hypothalamus):
T1-weighted axial cut. Image .
1, Mammillary body.
2, Cerebral aqueduct.
3, Superior colliculus.
20. Dr Ahmed Esawy
MRI of the Brain (hypothalamus):
T1-weighted sagittal cut.
1, Posterior commissure.
2, Midbrain.
3, Pituitary gland.
4, Récessus optique.
5, Corpus callosum.
21. Dr Ahmed Esawy
mammillary bodies
• are a pair of small round bodies, located on the
undersurface of the brain, that form part of the
limbic system.
• They are located at the ends of the anterior
arches of the fornix,
• named mammillary for their resemblance to
two breasts.
• They consist of two groups of nuclei, the
medial mammillary nuclei and the lateral
mammillary nuclei.
• Neuroanatomists have often categorized the
mammillary bodies as part of the hypothalamus
22. Dr Ahmed Esawy
tuber cinereum
• is a hollow eminence of gray matter situated
between the mammilary bodies behind, and
the optic chiasma in front.
• The tuber cinereum is part of the hypothalamus
• A prominence of the base of the hypothalamus,
extending ventrally into the infundibulum and
pituitary stalk
• tuber cinereum Layer of gray matter in the
hypothalamus that also forms part of the floor
of the third ventricle.
23. Dr Ahmed Esawy
(a) Drawing shows the hypothalamus (outlined with a dashed line) below an imaginary
line between the anterior commissure (AC) and the posterior commissure (PC).
The anterior boundary of the hypothalamus is the lamina terminalis (LT), which extends
between the optic chiasm (OC) and the anterior commissure.
The posterior boundary is imprecise; it is indicated by a line that extends between the
mamillary bodies (MB) and the posterior commissure.
The floor of the hypothalamus is formed by the infundibular stalk (IS), the tuber cinereum
(TC), and the mamillary bodies.
The major tracts related to the hypothalamus, the mamillothalamic tract (MT) and the
postcommissural fornix (PF), are also shown.
24. Dr Ahmed Esawy
Locations of Hypothalamic Nuclei with
Respect to the Medial-Lateral and
Rostral-Caudal Axes
.
Lateral AreaMedial AreaRegion*
Lateral preoptic nucleus,
lateral nucleus,
part of supraoptic
nucleus
Medial preoptic nucleus,
supraoptic nucleus,
paraventricular nucleus,
anterior nucleus,
suprachiasmatic nucleus
Anterior
Lateral nucleus, lateral
tuberal nuclei
Dorsomedial nucleus,
ventromedial nucleus,
arcuate nucleus
Tuberal
Lateral nucleusMamillary nuclei,
posterior nucleus
Posterio
*The rostral-caudal axis divides the hypothalamus into anterior, tuberal, and
posterior regions.
25. Dr Ahmed Esawy
Classification of Hypothalamic Lesions
• Developmental abnormalities
Craniopharyngioma, germinoma,hamartoma, lipoma , dermoid and
epidermoid cysts, arachnoid cyst, RCC, colloid cyst
• Primary tumors of the CNS
Hypothalamic-chiasmatic glioma, ganglioglioma, choristoma, perisellar
meningioma
• Vascular tumors
Hemangioblastoma, cavernoma
• Systemic tumors affecting the CNS
Metastasis, lymphoma, leukemia
• Inflammatory and granulomatous diseases
LCH, lymphocytic infundibuloneurohypophysitis, sarcoidosis, Wegener
granulomatosis, tuberculosis, syphilis, encephalitis
• Lesions arising from surrounding structures
Suprasellar pituitary tumor, ectopic posterior pituitary (EPP), aneurysms
26. Dr Ahmed Esawy
Classification of Hypothalamic Lesions
LesionsPathologic Process
Craniopharyngioma, germinoma,
hamartoma, lipoma, dermoid and
epidermoid cysts, arachnoid cyst, RCC,
colloid cyst
Developmental abnormalities
Hypothalamic-chiasmatic glioma,
ganglioglioma, choristoma, perisellar
meningioma
Primary tumors of the CNS
Hemangioblastoma, cavernomaVascular tumors
Metastasis, lymphoma, leukemiaSystemic tumors affecting the
CNS
LCH, lymphocytic
infundibuloneurohypophysitis,
sarcoidosis, Wegener
granulomatosis, tuberculosis, syphilis,
encephalitis
Inflammatory and granulomatous
diseases
Suprasellar pituitary tumor, ectopic
posterior pituitary (EPP), aneurysms
Lesions arising from surrounding
structures
27. Dr Ahmed Esawy
Characteristic Anatomic Locations and Key MR
Imaging Features of Hypothalamic Lesions
Key MR Imaging FeaturesLocationLesion
Solid and cystic components (solid:
heterogeneous enhancement; cystic:
variable signal intensity [T1 hyperintensity]),
calcification
Along suprasellar
portion of
stalk
Craniopharyngioma
Solid; iso- to hypointense with T1-weighted
sequences, iso- to hyperintense with T2-
weighted sequences relative to gray matter;
contrast enhancement; may be associated
with pineal infiltration
Upper part of
infundibulum
Germinoma
Solid, sometimes with cysts; isointense with
T1-weighted sequences, iso- to
hyperintense with T2-weighted sequences
relative to gray matter;
no contrast enhancement or calcification
Tuber cinereumHamartoma
28. Dr Ahmed Esawy
Characteristic Anatomic Locations and Key MR
Imaging Features of Hypothalamic Lesions
Key MR Imaging FeaturesLocationLesion
Heterogeneous signal intensity similar to
that of fat
Tuber cinereumOsteolipoma
Lobulated borders, isointense with T1-
and T2-weighted sequences relative to
CSF, hyperintense with FLAIR and
diffusion-weighted sequences, no
contrast enhancement
ParasellarEpidermoid cyst
Solid, inhomogeneous signal intensity
similar to that of fat
Suprasellar,
hypothalamic
(midline)
Dermoid cyst
Isointense relative to CSF, no contrast
enhancement
SuprasellarArachnoid cyst
29. Dr Ahmed Esawy
Characteristic Anatomic Locations and Key MR
Imaging Features of Hypothalamic Lesions
Key MR Imaging FeaturesLocationLesion
Smooth walls with variable signal
intensity, no solid component or
calcification
Supra- or intrasellarRCC
Solid; hypointense with T1-weighted
sequences,hyperintense with T2-
weighted sequences;
moderately heterogeneous contrast
enhancement
Hypothalamic-chiasmicGlioma
Isointense with T1- and T2-weighted
sequences,
variable contrast enhancement
InfundibulumChoristoma
Isointense with T1- and T2-weighted
sequences,
intense homogeneous contrast
enhancement,
dural tail
Suprasellar (rarely in stalk)Meningioma
30. Dr Ahmed Esawy
Characteristic Anatomic Locations and Key MR
Imaging Features of Hypothalamic Lesions
Key MR Imaging FeaturesLocationLesion
Cyst with enhancing mural noduleHypothalamusHemangioblastoma
Intense contrast enhancement,
bone destruction
without marked sellar enlargement
Stalk, hypothalamusMetastatic disease
Intense contrast enhancement,
associated intraand
extracranial lesions
StalkLCH
Leptomeningeal contrast
enhancement, associated
intra- and extracranial lesions
Stalk, suprasellar cisternSarcoidosis
Isointense relative to brain, strong
enhancement,
may contain cystic component or
hemorrhage;
sellar enlargement
Intrasellar center causing
upward displacement of
optic chiasm
Suprasellar pituitary
adenoma
Blood products, residual patent
lumen, phase
artifact
SuprasellarSuprasellar
aneurysm
35. Dr Ahmed Esawy
a Girl, 6-year-old, short stature, reduction of the visual field:
craniopharyngioma with predominant cystic component, thin wall calcifications seen on
CT, spontaneous hypersignal on T1 weighted images in relation with high cholesterol
concentration within the cyst.
36. Dr Ahmed Esawy
boy, 5-year-old: short stature, headache and vomiting; craniopharyngioma
with hydrocephalus, ‘‘egg-shell’’ calcification on CT,spontaneous T1 hyperintense
cystic part on MRI
37. Dr Ahmed Esawy
Girl 9-year old, visual disturbance since several months, papillary edema on
fundoscopy:craniopharyngioma with predominantly cystic component,peripheral rim
enhancement after contrast injection.
38. Dr Ahmed Esawy
Boy, 4-year-old, vomits since 2 weeks, palsy of the right 6th nerve:
craniopharyngioma with T1 isointense cystic component,
intra sellar solid component.
localized MR spectroscopy within the cyst demonstrates a doublet
lactate peak
40. Dr Ahmed Esawy
unenhanced and enhanced T1 craniopharyngioma
large intrasellar and suprasellar mass with cystic and enhancing components as well
as calcifications
DD : dermiod
43. Dr Ahmed Esawy
Girl, 11-year-old with
diabetes insipidus:
suprasellar germinoma
with cysts
44. Dr Ahmed Esawy
Boy, 14-year-old,
diabetes insipidus since
6 months: intra and
suprasellar germinoma
with heterogeneous solid
mass.
45. Dr Ahmed Esawy
Boy, 11-year-old, oculomotor palsy: suprasellar malignant
germinoma with heterogeneous enhancement
46. Dr Ahmed Esawy
Girl, 9-year-old,
headaches and visual disturbances: Synchronous lesions in pineal and suprasellar
regions
germinoma
47. Dr Ahmed Esawy
The mass enhances after gadolinium.
Continue with next images
T2
48. Dr Ahmed Esawy
MRI OF Hypothalamic hamartoma
T1: isointense to cerebral cortex
T1 C+ (Gd): no contrast enhancement
T2
iso- to hyperintense to cerebral cortex
the higher the proportion of glial cells, the higher the T2 signal
MR spectroscopy
reduced NAA/Cr
increased myoinositol
increased Cho/Cr compared to the amygdala has also been reported
53. Dr Ahmed Esawy
hamartomas on are enhanced sagittal T1-weighted MR images.
Here you can see the non-enhancing hamartoma attached to the tuber cinereum
between the pituitary stalk and mamillary body. There really is no differential diagnosis
58. Dr Ahmed Esawy
Girl, 1-year-old, MRI performed for psychomotor development delay: incidental
Rathke’s cleft cyst
59. Dr Ahmed Esawy
T1, T2 and T1-weighted images after gadolinium demonstrate another Rathke's cleft
cyst located in the pituitary gland
60. Dr Ahmed Esawy
• Suprasellar colloid cyst in a 44-year-old
T1+NO C
61. Dr Ahmed Esawy
a Boy, one-year-old, mildline defect with frontonasal encephalocele,
suprasellar arachnoid cyst, hypophysis hypoplasia
62. Dr Ahmed Esawy
Boy, 11-year-old, MRI for advanced puberty: incidental lipoma demonstrated, with
spontaneous T1 hypersignal posterior to the pituitary stalk
63. Dr Ahmed Esawy
Magnetic resonance images of the
hypothalamus
obtained (a) Axial spin-echo T2-weighted
(b) sagittal T2_Trufisp (c) coronal spin-
echo T2 images
all show well-defined lesions (arrowheads)
with heterogenous signal intensity. Areas of
haemorrhage are seen within the lesion
(mulberry appearance) that are surrounded
by a hypointense hemosiderin rim, which is
in keeping with the diagnosis of
cavernoma.
Cavernoma of the Hypothalamus
64. Dr Ahmed Esawy
Cavernoma of the Hypothalamus
A sagittal spin-echo T1-weighted magnetic resonance image obtained revealing the
hypothalamus and suprasellar cistern showing the cavernoma (arrowheads) causing
a mass effect and displacing the optic chiasm anteriorly and superiorly (white arrow).
79. Dr Ahmed Esawy
Boy, 4-year-old, diabetes insipidus: Langerhans cell hystiocytosis
with enlarged pituitary stalk, occipital osteolysis
80. Dr Ahmed Esawy
MRI reveals normal and abnormal hypothalamic-pituitary regions. In two healthy
controls, a hot signal in the pituitary lobe that is clearly separated from the dorsum
sella can be observed (A,B: T1-weighted).
A patient with LCH shows a thickened stalk and the loss of the hot spot in the
posterior lobe (C: T1-weighted).
81. Dr Ahmed Esawy
Gadolinium-enhanced MRIs show a hypothalamic mass in two patients with LCH (A,
B), each of which was histopathologically confirmed to be LCH by biopsy
82. Dr Ahmed Esawy
MRI of patients with neurodegenerative disease after treatment for multifocal LCH
show high signals at the basal ganglia (A: Flair, TR=9000) and the cerebellar dentate
nuclear area (B: Flair, TR=9000).
84. Dr Ahmed Esawy
Tl-weighted sagittal (a) after Gd-DTPA demonstrates a uniformly hyperintense lesion
with suprasellar (1) and hypothalamic components (2). (b) Tl-weighted coronal image
after Gd-DTPA demonstrates the cystic suprasellar portion to show marginal
enhancement (arrows); pituitary stalk (arrowheads). Note the relationship
of the lesion to the optic chiasm and the pituitary g1and
Sarcoidosis of the hypothalamus and pituitary stalk
85. Dr Ahmed Esawy
same patient before
Tl-weighted coranal, unenhanced
image, more posterior, shows the
granulomatous tissue in the
hypothalamus to be of spontaneously
high signal intensity.
Sarcoidosis of the hypothalamus
and pituitary stalk
86. Dr Ahmed Esawy
same patient before after 4 month Sagittal T1-weighted image demonstrates a
decrease in size of the hyperintense hypothalamic component, while the
presumed cystic suprasellar portion is unchanged
87. Dr Ahmed Esawy
same patient before after 6 month Sagittal (a) and coronal (b) image after Gd-DTPA
showa lterations in signal intensity and size in both parts of the lesion; the presumed
cystic component being more extensive.
93. Dr Ahmed Esawy
pituitary macroadenomas
classic 'snowman' configuration caused by constriction by the diaphragma sellae.
Notice the blood-fluid level, indicating hemorrhage.
97. Dr Ahmed Esawy
T1-weighted image of a thrombosed aneurysm with high signal intensity on the
unenhanced scan
98. Dr Ahmed Esawy
partially thrombosed aneurysm in the suprasellar cistern.
The patent lumen is black on these T1-weighted images.
It is surrounded by clot of different ages arranged in layers reaching from the lumen
to the wall. It resembles an onion cut in half
101. Dr Ahmed Esawy
the spread of the lesion along the meninges. The epicentre of the lesion is above
the sella
the main differential diagnosis of
the enhancing mass would include
meningioma, pituitary adenoma and
an aneurysm
102. Dr Ahmed Esawy
Differential Diagnosis for Lesions
Involving the Hypothalamus
• Some hypothalamic lesions show remarkable
consistency in location, such as hamartoma and
osteolipoma (in the tuber cinereum) .
• A thickened contrast-enhanced infundibulum is the
most typical manifestation of germ cell tumors,
lymphocytic hypophysitis, sarcoidosis,and LCH
• However, idiopathic, isolated infundibular stalk
thickening can be seen in cases of central DI without
evidence of infiltrative processes
103. Dr Ahmed Esawy
• Lesions of near isointensity relative to the brain include
germinomas,some hamartomas, and suprasellar
meningioma
• This signature MR spectroscopic finding associated
with hypothalamic hamartomas allows differentiation of
these neoplasms from other entities, such as
hypothalamic gliomas and metastatic deposits
104. Dr Ahmed Esawy
CNS lesions associated with central
precocious puberty
Hypothalamic hamartoma
Craniopharyngioma
Ependymoma
Optic fibromas
Optic glioma
Subarachniod cysts
Hydrocephalus
Cerberal vascular accidents
encephalitis
105. Dr Ahmed Esawy
Hypothalamic-pituitary gonadal axis
Arcuate nucleus regulate sexual
development Localized found between the
mamillary bodies And infundibulum