Universal interface for exchange of medical images via magneto-optical discs.

Digital images are the ever-growing basis of modern medical imaging and treatment. Despite the advent of the DICOM 3.0 standard for medical image communication it still requires cumbersome efforts to export images from imaging modalities to other computer systems. This is true especially for smaller institutions, which often have limited resources for standardized image transfer. To gain access even to these data we developed an exchange interface on the basis of magneto-optical discs (MO-discs), as they are usually available in most of the imaging modalities in use today. Unfortunately images on MO-discs are usually stored in formats specific for each manufacturer. Therefore special routines to access the data on MO-discs had to be developed for each company or even each scanner. Over 10,000 CT and MRI images including their header information from different General Electric and Siemens scanners were extracted successfully from MO-discs. The interface proved to be reliable and easy to handle by technicians. Support of additional manufacturers and of the DICOM 3.0 standard are work in progress.

Sinusoidal intrathecal infusion for assessment of CSF dynamics in kaolin-induced hydrocephalus.

OBJECTIVE: To evaluate whether changes of CSF outflow resistance and compliance in hydrocephalus can be assessed by an intrathecal infusion which is performed at a sinusoidal varying rate. METHODS: Hydrocephalus was produced in 10 Sprague Dawley rats by instillation of 0.0375 g of kaolin in 0.9% saline into the cisterna magna. Measurements were performed 4 weeks later: With each animal both, three successive constant rate infusions (0-0.02 ml/min) and a sinusoidal infusion (0-0.02 ml/min, frequency 0.006 Hz) were performed. 6 normal animals served as control. The pressure recordings of both infusion techniques were used for the assessment of the CSF outflow resistance. The time constant and the pressure volume index were calculated only from the sinusoidal input testing. RESULTS: The sinusoidal test as well as the constant rate infusion both demonstrated a severe impairment of CSF absorption. By the sinusoidal input, a decreased compliance was confirmed additionally. Thus, the sinusoidal infusion test demonstrated a high resistance and low compliance hydrocephalus in the kaolin-treated group. A simple graphical procedure is presented which allows an easy assessment of CSF dynamics by the sinusoidal infusion test.