[Weighted-averaging multi-planar reconstruction method for multi-detector row computed tomography].

Development of multi-detector row computed tomography (MDCT) has enabled three-dimensions (3D) scanning with minute voxels. Minute voxels improve spatial resolution of CT images. At the same time, however, they increase image noise. Multi-planar reconstruction (MPR) is one of effective 3D-image processing techniques. The conventional MPR technique can adjust slice thickness of MPR images. When a thick slice is used, the image noise is decreased. In this case, however, spatial resolution is deteriorated. In order to deal with this trade-off problem, we have developed the weighted-averaging multi-planar reconstruction (W-MPR) technique to control the balance between the spatial resolution and noise. The weighted-average is determined by the Gaussian-type weighting function. In this study, we compared the performance of W-MPR with that of conventional simple-addition-averaging MPR. As a result, we could confirm that W-MPR can decrease the image noise without significant deterioration of spatial resolution. W-MPR can adjust freely the weight for each slice by changing the shape of the weighting function. Therefore, W-MPR can allow us to select a proper balance of spatial resolution and noise and at the same time produce suitable MPR images for observation of targeted anatomical structures.

[Perioperative complications of patients with cementless femoral head replacement].

BACKGROUND: Studies have shown that use of cement is a risk factor for fat embolism in elderly patients with femoral neck fracture. We investigated the usefulness of the cementless femoral head replacement technique. METHODS: A retrospective study of 58 patients who had undergone this technique between January 1995 and May 2001 was conducted. Perioperative complications, hospital length of stay, activities of daily living, and postoperative mortality were studied. RESULTS: Of 58 patients, 42 (72.4%) were fe- males, and the mean age was 75.4 years. Twenty patients (69.0%) were classified as ASA class 2, and 50 patients (86.2%) had preoperative medical complications. Cardiovascular complications were the most prevalent, and 6 patients (10.3%) had serious perioperative complications, and postoperative death was noted in 1 patient within one month (1.7%), and 4 patients (6.9%) within one year. Average length of hospital stay was 64.2 days and activities of daily living were the same level as before the fracture. CONCLUSIONS: Early rehabilitation was possible and hospital length of stay and activities of daily living were not inferior to the other treatments. We believe that cementless femoral head replacement technique was useful for elderly patients.