Transverse geniculate ligament of the knee: appearance and frequency on plain radiographs.

The aims of the study were to determine the frequency of visualization of the normal transverse geniculate ligament (TGL) of the knee on lateral plain radiographs with magnetic resonance imaging (MRI) as a reference, and to determine features that make this ligament apparent on plain radiographs. 50 consecutive lateral plain radiographs and sagittal T1-weighted images of corresponding knees were evaluated prospectively. A TGL was considered visualized on plain radiographs when an opacity of soft-tissue density was apparent in the posterior part of the Hoffa's fat pad. The TGL was identified in 29 of the 50 (58%) sagittal MR images; a TGL was observed on the lateral plain radiographs of six patients (12%). Correlation with the MR images showed that, when visualized on plain radiographs, the ligament is at least 3 mm thick and completely surrounded by fat. Our study shows that the TGL is a normal variant that can be recognized frequently on lateral plain radiographs of the knee.

Ultrasound evaluation of soft tissue tumors.

Because of its availability, ultrasound should be the preferred initial modality for the evaluation of palpable superficial masses. Most ultrasound units are equipped with high frequency probes that allow superficial focalization. The differential diagnosis of soft tissue masses and the sonographic features of some benign and malignant soft tissue lesions are reviewed in this article. After an initial ultrasound evaluation confirming the presence of a tumor, the need for and the role of other imaging modalities can be determined. In selected cases ultrasound may obviate the need for further imaging. MRI and CT should be reserved for cases in which sonography fails to establish a specific diagnosis or to demonstrate the limits of the soft tissue mass.