Mr anatomy and pathology of the hypothalamus. pages 1 – 8 – text version anyflip anoxic zone

579

Downloaded from www.Ajronline.Org by 50.116.19.84 on 06/06/16 from IP address 50.116.19.84. Copyright ARRS. For personal use only; all rights reserved pictorial essay

MR anatomy and pathology of the hypothalamus

Daniel J. Loes,1 thomas J. Barloon,1 william T. C. Yuh,1 robert L. DeLaPaz,2 and yutaka sat

The hypothalamus, the ventral-most portion of the diencepha- difficult to determine. Children are affected more than adults.

Ion, surrounds the anterior inferior portion of the third ventricle the diencephalic syndrome (emaciation, alertness, hypemac-

(fig. 1). It functions primarily as an integrative mechanism for tivity, and pallor) is seen in up to 20% of children younger

Various autonomic and neuroendocrine activities including tem- than 3 years.Anoxic zone neurofibmomatosis type I is present in 20-50%

Perature regulation, water balance, behavior, and appetite. This of these patients. Pathologic findings are usually a low-grade

Pictorial essay illustrates the value of MR in depicting the normal astrocytoma, frequently the juvenile pilocytic variety. MR (fig.

Anatomy and abnormalities of the hypothalamic region. 4) typically shows a suprasellar mass involving the optic

Chiasm and hypothalamus that is hypointense on ti-weighted

Normal anatomy

4

At least 1 2 cell clusters or nuclei are recognized within the

Hypothalamic region (fig. 2). In actuality, the usefulness of

Anatomic subdivisions is limited because dendrites and axons

Of cell bodies overlap between various nuclei, resulting in

anoxic zone

Overlapping functions. The supraoptic and paraventriculam

Nuclei, which secrete vasopressin and oxytocin, have the

Most well-defined functions. With the exception of the mam-

Illamy nuclei, which are characteristic because of their contour,

The individual hypothalamic nuclei cannot be distinctly identi-

Fied on MR with standard spin-echo pulse sequences. How-

Ever, the boundaries of the hypothalamus (fig. 3) and hy-

Pothalamic abnormalities are well depicted by MR.

Pathology

Chiasmatic-hypothalamic glioma

Hypothalamic gliomas frequently invade the optic chiasm fig. 1.-hypothalamic nuclei (stippled area) surround anterior inferior

And vice versa; hence, the primary site of origin may be

Third ventricle. (adapted from netter [1].)

anoxic zone

Received july 9, 1 990: accepted after revision october 1 0, 1990. Los angeles, march 1990, and the american roentgen ray society, washington,

Presented at the annual meetings of the american society of neuroradiology, requests to T. J. Barloon.

DC, may 1990. City, IA 52242. Address reprint

1 department of radiology, the university of iowa college of medicine, iowa center, stanford, CA 94305.

2 department of radiology and nuclear medicine, stanford university medical

AJR 156:579-585, march 1991 0361-803X/91/1563-0579 © american roentgen ray society

580 LOES ET AL. AJR:156, march 1991

Downloaded from www.Ajronline.Org by 50.116.19.84 on 06/06/16 from IP address 50.116.19.84. Copyright ARRS. For personal use only; all rights reserved fig. 2.-A-D, normal coronal anatomy of hy-

anoxic zone

Pothalamic region viewed from anterior (A ) to

Posterior (D), as indicated in fig. 1. Hypotha-

Lamic nuclei: 1 = medial preoptic area, 2 = lateral

Preoptic area, 3 = paraventricular nucleus, 4 =

Dorsal hypothalamic area, 5 = periventricular

Arcuate nucleus, 6 = anterior hypothalamic area,

7 = lateral hypothalamic area, 8 = supraoptic

Nucleus, 9 = dorsal medial nucleus, 10 = ventro-

Medial nucleus, 1 1 = posterior hypothalamic

Area, 12 = mamillary nucleus. GP = globus pal-

Lidus, F = fornix, C = caudate, OT = optic tract,

5T = subthalamic nucleus.

AB

CD

Fig. 3.-A and B, normal sagittal anatomy of

Hypothalamic region shown on a line drawing (A)

And corresponding ti-weighted MR image (B).

Anterior 1 = anterior commissure, 2 = lamina

anoxic zone

Terminalis, 3 = optic chiasm; superior: 4 = hy-

Pothalamic sulcus; posterior: 5 = posterior corn-

Rnissure, 6 = rnarnillary bodies, 7 = interpedun-

Cular fossa; inferior: 8 = tuber cinereurn, 9 =

Infundibulurn, 3 = optic chiasrn; lateral (not

Shown): optic tracts, capsulopeduncular transi-

Tion zone. Note.-position of hypothalarnic sul-

Cus (groove between hypothalamus and thala-

Rnus) is located along anterior half of a line drawn

Between anterior (1) and posterior (5) cornrnis-

Sures.

AB

Images, is hypemintense on T2-weighted images, and nomas are low-grade malignant tumors that are radiosensi-

Enhances inhomogeneously

With contrast administration. Tive. On MR (fig. 5), gemminomas are usually mildly hypoin-

anoxic zone

Tense on ti -weighted images and hyperintense on T2-

Weighted images, but may be isointense on both pulse se-

Germinoma quence. They generally show homogeneous enhancement

Germinomas are most commonly located in the pineal with administration of contrast material.

Region; their next most frequent site is the hypothalamus,

Which can be affected without pineal involvement. Hypothal- primary CNS lymphoma

Amic germinomas affect males and females equally, unlike

Pineal region germinomas, which show a strong male predom- the prevalence of primary CNS lymphoma is higher in AIDS

Inance. Tumor spread may occur via CSF pathways. Gemmi-

Patients and other immunosuppressed individuals. MR (fig.

AJR:156, march 1991 MR OF NORMAL AND PATHOLOGIC HYPOTHALAMUS 581

anoxic zone

Downloaded from www.Ajronline.Org by 50.116.19.84 on 06/06/16 from IP address 50.116.19.84. Copyright ARRS. For personal use only; all rights reserved fig. 4.-chiasmatic-hypothalamic glioma in a 2-year-old emaciated and hyperactive girl.

A, sagittal ti-weighted MR image shows large midline mass involving optic chiasrn (straight arrow) and hypothalamus (curved arrow).

B and C, coronal ti-weighted images before (B) and after (C) contrast administration show nonuniform enhancement of tumor, which extends

Superiorly to foramen of monro causing an obstructive hydrocephalus.

Fig. 5.-germinoma in an 18-year-old man with diabetes insipidus. In floor of anterior third ventricle

A and B, sagittal TI-weighted MR images before (A) and after (B) contrast administration show enhancing masses ventricle.Anoxic zone

(straight black arrow) and pineal region (curved arrow). Optic chiasm (white arrow) is not involved.

C, axial ti-weighted image obtained after contrast administration shows third enhancing mass (arrow) in left lateral

(reprinted with permission from hawes et al. [2].)

6) typically shows solitary or multicentric well-defined mass hypothalamus. Hypothalamic hamartomas are a cause of

Lesions located in deep gray nuclei, periventricular white mat-

Ter, or corpus callosum. Primary CNS lymphoma tends to be precocious puberty and laughing seizures in children; boys

Slightly hypointense on ti -weighted images, but may be

Hypemintense, isointense, or hypointense with respect to gray are affected more often than girls.Anoxic zone hypothalamic hamartomas

Matter on T2-weighted images. Primary CNS lymphoma typ-

Ically shows contrast enhancement, although signs of central also may be found incidentally in adults, where they may

Necrosis may be seen in AIDS patients.

Mimic low-grade gliomas. MR shows a sessile (fig. 7) or

Hypothalamic hamartoma

Polypoid (fig. 8) mass in the tuber cinemeum region of the

Hypothalamic hamartomas are rare congenital malfomma-

Tions located in the region of the tuber cinereum-mamillamy hypothalamus that is isointense on ti -weighted images and

Body. They comprise neuronal tissue similar to that of the

Isointense or mildly hypemintense on T2-weighted images. The

Lesions are stable in size over time and typically do not show

anoxic zone

Contrast enhancement.

Histiocytosis are a diverse group of diseases of un-

A common pathologic feature of being

The histiocytoses

Known cause with

582 LOES ET AL. AJR:156, march 1991

Fig. 6.-primary CNS lymphoma in a 62-year-

Old man with increasing confusion over 1 month.

A-C, sagittal ti-weighted MR images ob-

Tamed before (A) and after (B) contrast admin-

Istration and axial TI-weighted image after con-

Trast administration (C) show enhancing mass

Lesions in hypothalamus (arrows) and left thala-

Mus (arrowheads).

Downloaded from www.Ajronline.Org by 50.116.19.84 on 06/06/16 from IP address 50.116.19.84. Copyright ARRS. For personal use only; all rights reserved D, axial T2-weighted MR image shows sur-

Rounding edema.Anoxic zone

AB

Fig. 7.-hypothalamic hamartoma in a 5-year-

Old girl with precocious puberty.

A and B, coronal ti-weighted (A) and T2-

Weighted (B) MR images show a midline hy-

Pothalamic mass (arrows) bulging into inferior

Floor of third ventricle. Lesion is isointense on

.C),. .4*s- both TI- and T2 weighted images and is cen-

.* I tered in region of tuber cinereum.

H#{188}t

Prolifemations of macmophages. Several organ systems may sarcoidosis

Be involved, including skin, bone, eyes, and CNS. In the CNS,

Hypothalamic involvement frequently results in diabetes insi- samcoidosis is a systemic, noncaseating gmanulomatous

Pidus. MR (fig. 9) shows a suprasellar mass involving the disease of unknown cause. It is common in blacks and usually

anoxic zone

Infundibulum and hypothalamus that is hypointense on ti – occurs in the third to fourth decades. CNS involvement occurs

Weighted images, hyperintense on T2-weighted images, and in 5% of individuals and has two main forms: leptomeningeal

Enhances homogeneously with administration of contrast.

AJR:156, march 1991 MR OF NORMAL AND PATHOLOGIC HYPOTHALAMUS 583

Fig. 8.-hypothalamic hamartoma in a 66-

Year-old-man. 1,_

A and B, sagittal (A) and coronal (B) ti-

Weighted MR images show an incidental pedun-

Culated isointense mass off the tuber cinereum.

Hypothalamic hamartomas have a fairly char-

Acteristic MR appearance; however, follow-up at

6-month to 1-year intervals is necessary to cx-

Downloaded from www.Ajronline.Org by 50.116.19.84 on 06/06/16 from IP address 50.116.19.84.Anoxic zone copyright ARRS. For personal use only; all rights reserved dude a low-grade glioma.

Fig. 9.-histiocytosis in a 9-year-old boy with _s_,-

Diabetes insipidus. Medical history was signifi- A

Cant for histiocytosis involving temporal bone.

A and B, sagittal ti-weighted MR image ob-

Tamed after contrast administration (A) and axial

12-weighted image (B) show large enhancing

Hypothalamic mass splaying cerebral peduncles

(arrows).

C and D, corresponding images 3 weeks after

Low-dose radiation treatment show significant

Decrease in size (C) and signal intensity (D) of

Lesion.

Dramatic response to low-dose radiation

Strongly favors a diagnosis of histiocytosis over

Hypothalamic glioma.

And parenchymal. Leptomeningeal disease is most common ectopic posterior pituitary gland

anoxic zone

And frequently involves the infundibulum and hypothalamus. Ectopic posterior pituitary glands may be caused by trauma

Or the presence of a mass, or may be congenital in origin.

The disease usually responds to steroid treatment. The lep- although an ectopic posterior pituitary gland may be associ-

Ated with dwarfism, many of these patients are asymptomatic.

Tomeningealform of CNS sarcoidosis on MR (fig. 1 0) typically normally, the supraoptic and paraventricular nuclei secrete

Is isointense on ti -weighted images, is mildly hypemintense

On T2-weighted images, and enhances homogeneously with

Administration of contrast material.

584 LOES ET AL. AJR:156, march 1991

4,.. Fig. LO.-5arcoidosis in a 38-year-old black

anoxic zone

A woman with recent onset of visual difficulties.

A, sagittal ti-weighted MR image shows ab-

Normal thickening in hypothalamic region (ar-

Rows) involving tuber cinereum, mamillary bed-

Ies, and infundibulum.

B, after a 3-week course of steroids given

Because of prior diagnosis of sarcoidosis, a sec-

Downloaded from www.Ajronline.Org by 50.116.19.84 on 06/06/16 from IP address 50.116.19.84. Copyright ARRS. For personal use only; all rights reserved ond sagittal ti-weighted MR image shows dra-

Matic resolution of findings with return to normal

Hypothalamic region anatomy. Note normal

Mamillary bodies (curved arrow), tuber cinereum

(straight arrow), and infundibulum (arrowhead).

Tuberculosis also can produce basilar lepto-

anoxic zone

Meningeal disease; hence, when there is no evi-

Dence for sarcoidosis outside the CNS, confir-

Mation with CSF studies or biopsy is necessary

Before steroid therapy is begun.

Fig. 1 1.-ectopic posterior pituitary gland in

A 7-year-old boy with short stature.

A and B, sagittal (A) and coronal (B) ti-

Weighted MR images show small hyperintense

Oblong nodule (arrows) in inferior portion of

Tuber cinereum. Pituitary tissue within sella does

Not show high signal in its posterior portion, and

An infundibulum connecting pituitary gland to

Hypothalamus is not present.

K-

I__

B

Fig. 12.-wernicke encephalopathy in a 60-

Year-old alcoholic man with encephalopathy,

Ataxia, and oculomotor dysfunction.

A and B, sagittal (A) and coronal (B) ti-

anoxic zone

Weighted MR images show striking atrophy of

Mamillary bodies.

Vasopressin and oxytocin within liposome vesicles that are within the posterior lobe of the pituitary. Transection,

Compression, or absence of the infundibulum and its neumo-

Transported along axons within the neumohypophyseal tract hypophyseal tract results in the proximal build-up of neumose-

Cretory granules within liposome vesicles before the point of

To the posterior lobe of the pituitary. A recent experiment by interruption, hence displacement of the normal bright signal

Of the posterior lobe of the pituitary out of the sella. MR

Kuchamczyk et al. [3] showed that the phospholipid membrane

Component of these hormone-carrying vesicles, rather than

anoxic zone

The actual hormones, best explains the normal bright signal

AJR:156, march 1991 MR OF NORMAL AND PATHOLOGIC HYPOTHALAMUS 585

Images (fig. 1 1) show a small midline mass within the tuber summary

Cinereum-infundibular region that has homogeneous high- while MR can nicely depict hypothalamic region anatomy

And disease, definitive diagnosis of hypothalamic lesions me-

Signal intensity on ti -weighted images and is isointense on quires correlation with history, clinical findings, and frequently

Biopsy, as several entities may mimic each other.

T2-weighted images. The absence of both a normal infundib-

Ulum and high-signal-intensity tissue within the posterior sella

On ti -weighted images is necessary to confirm the diagnosis.Anoxic zone

Downloaded from www.Ajronline.Org by 50.116.19.84 on 06/06/16 from IP address 50.116.19.84. Copyright ARRS. For personal use only; all rights reserved wernicke encephalopathy

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Downloaded from www.Ajronline.Org by 50.116.19.84 on 06/06/16 from IP address 50.116.19.84. Copyright ARRS. For personal use only; all rights reserved this article has been cited by:

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4. Yukunori korogi, mutsumasa takahashi. 1995.Anoxic zone current concepts of imaging in patients with pituitary/hypothalamic dysfunction.

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5. J. WIKNER, D. E. H. ANDERSSON, L. WETTERBERG, S. RÖJDMARK. 1995. Impaired melatonin secretion in patients

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