Orthosorb resorption evaluation using MRI and histologic analysis.

Resorbable bone fixation devices may be used in various surgical procedures for internal fixation in place of traditional metallic devices. Currently, there is no radiographic technique for tracing the postsurgical location and resorption of these devices. This study was undertaken to ascertain whether magnetic resonance imaging is a suitable tool for performing such evaluations. Using an animal model, the authors investigated the correlation over time between the magnetic resonance image of a surgically implanted pin and its histologically verified location and state.

Volumetric rendering of MR images.

The authors developed new techniques for three-dimensional display of magnetic resonance (MR) images that preserve soft-tissue definition, are fully automatic, and work with routinely used section thicknesses. MR images are segmented, selectively enhanced, and displayed by means of a volumetric rendering algorithm. These techniques were used to illustrate normal anatomy of the brain, knee, and liver. Three-dimensional rendering of balanced spin-echo images shows the ventricles and extracerebral veins and of T1-weighted images, the sulci and gyri. The large hepatic and portal vessels can be seen with these enhancement techniques. Three-dimensional views of the knee reveal articular surfaces of the tibia and clearly depict menisci and posterior and anterior cruciate ligaments. These techniques make it possible to image multiple soft tissues simultaneously while preserving the detail contained in the original images. Three-dimensional presentation of complex, overlapping anatomic regions is helpful in surgical planning and should lead to improved diagnosis.