Degeneration of the intervertebral disc from a combination of factors can result in herniation, particularly at the L4-5 and L5-S1 levels. The intervertebral disc is responsible for the attachment of vertebral bodies to each other, providing flexibility and absorbing and distributing the weight applied to the spinal column. With aging, the disc undergoes significant changes in volume and shape. Lumbar disc herniations are believed to result from anular degeneration that leads to a weakening of the anulus fibrosus, leaving the disc susceptible to anular cracking and tearing. MRI is the imaging of choice to evaluate intervertebral disc herniations, but CT and xray can also be used.
Sunday, May 3, 2009
Tuesday, April 21, 2009
Thoracic
The image to the right is a MRI image of a thoracic vertebrae compression fracture. Compression fracture of the vertebral body is common, especially in older adults. These fractures are most commonly caused by osteoporosis. More severe compression fractures can cause significant pain, which can lead to the inablity to perform daily activities. Vertebral compression fractures affect approximately 25 percent of all postmenopausal women in the United States. General physicians can help patients prevent compression fractures by diagnosing and treating predisposing factors, identifying high-risk patients, and educating patients about measures to prevent falls.
Sunday, April 19, 2009
cervical
To the right is a sagittal MRI image of the cervical spine showing cervical metastasis. Metastais is the spread of a disease-producing agency (such as cancer cells) from its inital or primary site of disease to another part of the body. So this patient could have had a primary cancer site of the lung or brain and the cancer has now spread to the bone in their cervical spine. The white spots or patches on the cervical vertebrae in this MRI image is the diseased portion of the vertebrae.
Sunday, April 12, 2009
Neck Lipoma
To the left is a CT axial soft tissue neck image. The large dark oval you see is a lipoma of the neck. Lipomas are benign tumors composed of mature fat cells. They usually develop as discrete rubbery masses in the subcuateous tissues of the trunk and proximal extremity. Lipomas are the most common type of soft tissue tumors. They can usually be removed they surgical excision or liposuction.
Sunday, March 22, 2009
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.
Sunday, March 1, 2009
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.
Saturday, February 21, 2009
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.
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