Mri t1 sagittal view radiograph

This radiological image, obtained by magnetic resonance imaging (MRI), shows the brain as clearly as the actual brain itself (review the NOTE on radiologic imaging with Figure 3). This is the way the brain will be seen in the clinical setting. The view presented is called a T1-weighted image. Note that the CSF is dark in this image, including the ventricles, the subarachnoid space, and cisterns (see Figure 21). The bones (tables) of the skull are visible as a dark space, while the bone marrow, including its replacement by fatty tissue, and layers of soft tissue (and fatty tissue) of the scalp are well demarcated (white). The superior sagittal sinus can also be seen (see Figure 13 and Figure 21).

The various structures of the brain can easily be identified by comparing this view with the photographic view of the brain shown in the previous illustration, including the lobes of the brain. The corpus callosum can be easily identified, with the cingulate gyrus just above it and the lateral ventricle just below it (see also Figure 30). Various fissures (e.g., parieto-occipital, calcarine) can also be identified along with some cortical gyri (e.g., area 17, see Figure 41B). The space below the occipital lobe is occupied by the tentorium cerebelli (discussed with Figure 15B); the straight sinus, one of the dural venous sinuses, runs in the midline of the tentorium (see Figure 21).

The thalamus (the diencephalon) is seen below the lateral ventricle, and the tract immediately above it is the fornix (see Figure 70A). The structure labeled septum pellucidum separates the lateral ventricles of the hemispheres from each other (shown clearly in Figure 28A and Figure 30). The pineal is visible on this radiograph at the posterior end of the thalamus (just below the splenium of the corpus callosum); the pineal gland is cystic in this case, making it easy to identify. The pituitary gland is situated within the pituitary bony fossa, the sella turcica (see Figure 21).

Below the thalamus is the brainstem — its three parts, midbrain, pons, and medulla, can be identified. The tectum (with its four colliculi) is seen behind the aqueduct of the midbrain (see Figure 21). Posterior to the tectum is a CSF cistern (see Figure 28A, the guadrigeminal cistern). The fourth ventricle separates the cerebellum from the pons and medulla. The medulla ends at the foramen magnum and becomes the spinal cord.

The cerebellar folia are quite distinct on this image. The location of the cerebellar tonsil(s) should be noted, adjacent to the medulla and immediately above the foramen magnum, the "opening" at the base of the skull (see discussion on tonsillar herniation with Figure 9). The location of the cerebello-medullary cistern, the cisterna magna, behind the medulla and just above the foramen magnum is easily seen (see Figure 3 and Figure 21).

The remaining structures are those of the nose and mouth, which are not within our subject matter in this atlas.

Clinical Aspect

This is a most important view for viewing the brain in the clinical setting. Abnormalities of structures, particularly in the posterior cranial fossa, can be easily visualized. Displacement of the brainstem into the foramen magnum because of a developmental disorder, known as an Arnold-Chiari malformation, will cause symptoms related to compression of the medulla at that level; in addition, there may be blockage of the CSF flow causing hydrocephalus (see Figure 21).

Marrow of skull Tables of skull ■

Cingulate gyrus Corpus callosum

Septum _

pellucidum

Fornix

Pituitary gland

Midbrain-

Medulla

Spinal cord

F = Frontal lobe P = Parietal lobe O = Occipital lobe

Th = Thalamus

C = Cerebellum

Marrow of skull Tables of skull ■

Cingulate gyrus Corpus callosum

Septum _

pellucidum

Pituitary gland

Midbrain-

Foramen Magnum Location Mri

Superior sagittal sinus

Splenium of corpus callosum

Parieto-occipital fissure

Straight sinus Calcarine fissure

Aqueduct of midbrain

Tectum

Tentorium cerebelli

4th ventricle Cisterna magna Tonsil

Foramen magnum

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Responses

  • MYRTLE
    Where is the foramen magnum located?
    6 years ago
  • max
    How looks pituitary gland mri pictures?
    6 years ago
  • massawa
    Where is the pituitary gland located?
    6 years ago

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