cranial nerves and vessels

Achondroplasia is a genetic bone disorder in which a child's arms and legs are short in proportion to their body length. It is the most common type of dwarfism. Achondroplasia is inherited by an autosomal dominant gene that causes abnormal cartilage formation. This sagittal T1-weighted MRI image shows some of the abnormalities found in an achondroplasia skull. There is a large cranial top with a small skull base. There is a kink in the cerviomedullary area. The forehead is prominent with a depressed nasal bridge. The foramen magnum is narrowed and the suprasellar cistern is enlarged. Also to go with what we learned about this week the straight sinus is vertically oriented instead of the normal horizontal orientation.

sinusitis

Sinusitis is an inflammation of the sinuses and nasal passages. Sinusitis can be categorized as chronic or acute. Acute sinusitis usually lasts less than 8 weeks or occurs no more than 3 times per year. Medications are usually effective against acute sinusitis. Chronic sinusitis, however, lasts longer than 8 weeks or occurs more than 4 times per year. Sinusitis can be caused by allergens, viral infections, pollutants, and fungi. Computed tomography is the imaging modality of choice to view the sinuses. The main goals in treating a sinus infection or sinusitis involve reducing the swelling in the nasal passages and sinuses, getting rid of the infection, adaquate drainage from the sinuses, and maintaining open sinuses.

orbit

To the right are MRI images of the orbits. These images show a meningioma on the left optic nerve. A meningioma arises from the meninges covering the optic nerve. It is a mass lesion surrounding the optic nerve. It enhances wonderfully with MRI contrast imaging. Linear bands of enhancement, such as these, represent a tumor encasing the optic nerve.

pituitary

To the left is a MRI image of a pituitary adenoma. Pituitary adenomas are usually benign, slow-growing tumors that form from cells in the pituitary gland. Pituitary adenomas account for around 15 percent of primary brain tumors. These adenomas are split into to seperate types based on their size. A microadenoma is less than 10mm in diameter and a macroadenoma is greater than 10mm in diameter. In the case of the pituitary tumor being malignant it would be called a pituitary carcinoma, which are rare. Pituitary adenomas can produce an active hormone in large amounts, in which case the patient would have symptoms of hormonal imbalance. The size of the adenoma can also cause symptoms in patients. If it becomes too large it can invade close structures and/or compress on other brain structures hindering their function. Pituitary adenomas can be treated with medical or surgical therapies dependent upon the nature and size of the tumor.

These coronal and axial CT images show an osteoma of the external auditory canal. An osteoma is a benign cartilage or bony growth. There is no need for treatment unless it enlongates and touches the eardrum or prevents drainage. If this happens it can cause hearing loss and/or infection and would need to taken out surgically.

brain

Cerebrovascular accident is a very common brain pathology. CVA also known as a stroke is the sudden death of some brain cells due to the lack of oxygen when the blood flow to the brain is impaired by blockage or rupture of an artery to the brain.

There can be several things that can happen to cause a CVA. For example, an artery to the brain my be blocked by a thrombosis(blood clot). This clot or even a piece of plaque can break loose and travel to the brain by way of the circulation system and lodge in an artery in the brain, sort of acting as a plug by blocking or stopping blood flow. A cerebral hemmorage or bleeding in the brain, from an aneurysm for example, can also cause a stroke.