Hypothalamus, the ventral-most portion of the diencephaIon,

surrounds the anterior inferior portion of the third ventricle

(Fig. 1 & 2).

Fig.: Fig1.Drawing shows the hypothalamus (outlined with a pink color)AC-Anterior commissure,PC-Posterior commissure,MB-Mamillary bodies,PP-Posterior pituitary,AP-Anterior pituitary.

Fig.: Fig(1).T1 sagittal demonstrates anatomy of hypothalamus. AC-anterior commissure,PC-posterior commissure,MB-mamillary bodies, TC-tuber cinerium,IS-infundibular stalk,OC-optic chiasma,PP-posterior pituitary gland.

Fig.: Fig(2).Sagittal T1 contrast- the infundibular stalk and pituitary gland show normal homogeneous enhancement, which reflects their lack of a blood-brain barrier.

It functions primarily as an integrative mechanism for various autonomic and neuroendocrine activities including temperature regulation, water balance, behavior and appetite. 

There is variability concerning the appearance of hypothalamic lesions The hypothalamus is susceptible to involvement by a variety of processes,  including developmental abnormalities, primary tumors of the central nervous system (CNS), vascular tumors, systemic tumors affecting the CNS, inflammatory and granulomatous disease. The hypothalamus may also be involved by lesions arising from surrounding structures such as the pituitary gland. Since the pathologic spectrum of hypothalamic disease is so diverse, knowledge of the imaging appearance of diseases specific to pituitary and hypothalamus is important for accurate diagnosis and treatment.

The purpose is:

1.  To describe the anatomy of the hypothalamus

2.  To review Imaging features of various hypothalamic lesions.

3.  To discuss differential diagnosis for hypothalamic lesions on 

     MR imaging