Computed tomography

As the orbit and surrounding sinuses have tissues with naturally high radiographic contrast, thin-slice computed tomography is the most effective and economical tool for the initial imaging of the orbit (Figure 10.7).

For a suspected orbital mass, a single run of axial scans with intravenous contrast (unless contraindicated), together with coronal reformats images, is generally sufficient to give a probable diagnosis and allow planning of surgery or medical therapy; if needed, direct coronal imaging may give greater detail of the relationship of the mass to the optic nerve or rectus muscles. For planning the repair of blowout fractures, or the diagnosis and treatment of thyroid orbitopathy, a single run of direct coronal scans (without contrast) is often sufficient. Parasagittal reformats along the plane of the vertical recti and optic nerve may also be of help in orbital floor trauma and in evaluating the relationship of lesions to the optic nerve (Figure 10.8).

For orbital pathology arising in bone, or where secondary bone invasion is suspected, then it is important to obtain images with

Figure 10.7 A patient with dysthyroid orbitopathy, showing gross proptosis and enlargement of extraocular muscles, as imaged by (a) axial and (b) coronal soft tissue CT scans through the mid-orbits.

Figure 10.7 A patient with dysthyroid orbitopathy, showing gross proptosis and enlargement of extraocular muscles, as imaged by (a) axial and (b) coronal soft tissue CT scans through the mid-orbits.

Figure 10.8 Parasagittal reformatted CT, imaged along the line of the vertical recti, showing the inferior rectus muscle to be free from the site of a repaired orbital floor fracture.

both soft tissue and bone window settings. Spiral CT allows greatly reduced imaging time and three-dimensional studies may be of help in planning major cranio-facial reconstruction (Figure 10.9).

Figure 10.9 Three-dimensional CT reformat for a patient with severe clefting of the facial soft tissues and bone.

Was this article helpful?

0 0
How To Reduce Acne Scarring

How To Reduce Acne Scarring

Acne is a name that is famous in its own right, but for all of the wrong reasons. Most teenagers know, and dread, the very word, as it so prevalently wrecks havoc on their faces throughout their adolescent years.

Get My Free Ebook


Post a comment