Letter: Computerized axial tomography in patients with exophthalmos

Congenital generalized multicentric myofibromatosis with orbital involvement

We studied a rare case of congenital myofibromatosis of the orbit as part of a generalized multicentric disease in a 5-month-old boy. The ultrasonographic and computed tomographic findings were those of a low-reflective, firm, vascularized, lesion with heterogeneous internal structure. The histopathologic findings showed vascular channels with large polygonal cells and transition toward myofibroblasts with interwoven collagen fiber bundles.

The use of computed tomography and ultrasonography in the evaluation of orbital masses

The combined use of computed tomography scans with multiplanar reformation and ultrasonography makes it possible to locate orbital masses with a high degree of accuracy, and sometimes even to determine their histological nature without surgical biopsy. One of the unique features of computed tomography is its ability to distinguish both normal and abnormal structures of various tissue densities; this has contributed to very low false positive and false negative rates. Ultrasonography, while of limited use in the detection of posterior orbital lesions or lesions involving the orbital bones, provides an excellent cost-effective screening test for anterior and midorbit disease. It is also useful for the detection of extraocular muscle enlargement secondary to thyroid disease. In this article, a review of the characteristics and techniques of computed tomography and ultrasonography is followed by discussion of the advantages and limitations of each modality in the evaluation of six common types of orbital tumefaction.

CT-evaluation of extraocular muscles - anatomic-CT-correlations

CT evaluation of the extraocular muscles is unsatisfactory in the commonly used axial and coronal planes. Based on the analysis of anatomic and computed tomographic sections and reformations in various planes, optimal examination techniques for the evaluation of the extraocular muscles are discussed. Their anatomic relationship to other clinically and surgically important orbital structures is shown. As a rule, visualization of an eye muscle is optimal if the plane of section or reformation is parallel to its course. Judgments regarding muscle size should be based only on true cross-sections obtained from reformations 90 degrees to the course of the individual muscle.

Orbital dermoid diagnosed by computed tomographic scanning

In a 20-year-old man, computed tomography revealed that an orbital mass in the region of the lacrimal gland fossa had low density attenuation values (below water), indicating a fat-containing tumor. At surgery, we found a dermoid cyst of the oil cyst type.

False diagnosis of orbital apex tumor by CAT scan in thyroid eye disease

Computerized transaxial tomography is now the procedure of choice in diagnosing exophthalmos. Caution must be exercised, however, in interpreting the results. The patient reported here had a swollen inferior rectus muscle that simulated an orbital apex tumor on CAT scan.