A comparison of imaging techniques with surgical experience in orbital injuries. A prospective study.

The aim of the study is to compare the effectiveness of computerised tomography (CT) and magnetic resonance (MR) imaging in diagnosing herniation and entrapment of orbital soft tissues in orbital fractures. 15 consecutive patients with clinical signs and symptoms of medial orbital wall injury were examined with CT and MR. The data were subsequently compared with the findings of the surgical exploration with regard to the extent of the wall fractures, the presence of soft tissue herniation and its entrapment. CT and MR were equally accurate in demonstrating or excluding orbital wall fractures but both modalities slightly underestimated their incidence. CT and MR underestimated the actual incidence of soft tissue herniation and entrapment when compared with the surgical findings but the extent of soft tissue herniation and entrapment were demonstrated more clearly by MR than by CT scanning. MR imaging when available should therefore be used as the initial imaging modality and CT held in reserve for confirmation as positioning in the MR unit is easier and more comfortable for recently injured patients who may well have other injuries.