Diagnosis and treatment of osteochondritis dissecans.

This clinical practice guideline is based on a series of systematic reviews of published studies in the available literature on the diagnosis and treatment of osteochondritis dissecans of the knee. None of the 16 recommendations made by the work group is graded as strong; most are graded inconclusive; two are graded weak; and four are consensus statements. Both of the weak recommendations are related to imaging evaluation. For patients with knee symptoms, radiographs of the joint may be obtained to identify the lesion. For patients with radiographically apparent lesions, MRI may be used to further characterize the osteochondritis dissecans lesion or identify other knee pathology.

Imaging spectrograph for interstellar shocks: a narrowband imaging payload for the far ultraviolet.

We present an imaging spectrometer developed for narrowband imaging at 1035 A with high (approximately 1-arc sec) spatial resolution over a modest field of view (approximately 5 arc min). The instrument is based on a conventional Gregorian telescope with aberration-corrected holographic rulings on the secondary optic. These aberration-correcting rulings enable stigmatic imaging in diffracted light with a minimum number of optical elements, thereby maintaining a high system efficiency. The capabilities of this instrument allow us to map the distribution of UV-emitting material in the hot (approximately 300,000 K) plasma from shocks in supernova remnants. Although this design is optimized for imaging near 1035 A, the basic concept can be applied to provide narrowband imaging or long-slit imaging spectroscopy at any wavelength. In addition, a larger field of view is possible with a corresponding loss in spatial resolution.