Correlation of A-Scan Echography and Computed Tomography of Orbital Tumors

Abstract

The representation of orbital diseases with A- and B-scan echography began in 1958 (BAUM and GREENWOOD). In contrast to the abstract picture of this method, the surgeon may have a comprehensible representation of the orbit through CT tomography with the 160x160 matrix. It is our aim to contrast both methods and compare them with the histologicsection. Figure 1 shows A-scan echograms of normal orbit tissue obtained in the (a) transbulbary and (b) parabulbary positions. We use a 7200 M A A-scan instrument (KRETZ). In examinations of the orbit A-scan, the height, width, angle kappa, borders, and the deform ability of the echo spikes are analyzed. The healthy orbital echogramis acoustically heterogeneous; it reflects and diminishes ultrasound. There is a small series of densely spaced echo spikes, which have their greatest height at the left side of the orbital echogram and which decrease very quickly toward the right. According to OSSOINIG the classification of orbital lesions is divided into three different heights of reflectivity. These methods are too detailed to describe here.