Data processing of digital recordings of microscopic examination of urinary sediment.

The analysis of urine was actually the beginning of laboratory medicine. The important part of the routine urinalysis is the microscopic examination of the urinary sediment [Fogazzi and Cameron, Kidney Int 1996;50(3):1058-1068; Diamondopoulos, Am J Nephrol 1997;17(3-4):222-227; Fogazzi et al., Clin Chem Lab Med 1998;36(12):919-924]. The microscopic examination of the urine is the least standardised and most time-consuming part of the routine urinalysis, even though it is now known that careful analysis of the sediment components can provide early information concerning the anatomic integrity of the kidney and the existence and extent of recent damage. Our objective was to develop a computerised image processing system and an interactive software package for the backing of clinicians, medical research and medical students. The system consists of: (a) a CCD camera attached to a microscope. (b) Digital processing device. (c) Computer equipped with special video card. (d) Printer. (e) Software. Image analysis begins with a digital capturing of the image as data. The image is detected with 256 gray levels and displayed with a resolution of 512x512 pixels. A pixel is an abbreviation for picture elements and represents the dots on a screen. Once the image is acquired in digital format, the data can be manipulated for changes in the display image or for statistical purposes. The digitised microscope images are a very important part of renal diagnosis and of teaching nephrology.