PubMed Health⌕ Search

Biomedical subjects

Paul Halasz

Publications and source records attributed to Paul Halasz.

4 recordsLinked to original sources
PubMed2006

A method for tracking rats in a complex and completely dark environment using computerized video analysis.

The automated tracking of rodents in open field environments has become a standard laboratory technique for the investigation of the effects of drugs, novel therapeutic interventions and genetic mutations on behavior. Here, we develop an extension of this technique that permits tracking in full darkness through a complex ('enriched') environment comprising naturalistic structures such as tunnels and hides. To eliminate unwanted light reflections and tape noise, we developed a unique video filter that combines the advantages of differential and non-differential filtering. This filter enabled the tracking of albino rats against a relatively dark background to an accuracy of approximately 97% compared to hand tracking of the same animal, irrespective of whether the rat was inside a hide box or tunnel or out in the open field. The system as a whole can be easily deployed using standard PCs and inexpensive infrared cameras and lights.

Algorithms↗
PubMed2006

Bone scintigraphy predicts outcome of steroid injection for plantar fasciitis.

UNLABELLED: Plantar fasciitis is a common cause of foot pain and may be disabling. Although localized injection is painful, anesthetics or corticosteroids can relieve symptoms well. Bone scintigraphy can confirm the diagnosis. We hypothesized that blood-pool abnormalities could provide prognostic information on the response to such injections. METHODS: We devised scintigraphic criteria that graded the blood-pool abnormalities as being localized to the plantar enthesis, being localized to half the length of the aponeurosis, or involving the whole aponeurosis. We evaluated 24 patients with an established diagnosis of plantar fasciitis, 8 of whom had bilateral disease, leading to a total of 32 feet injected. RESULTS: After injection, pain was relieved either completely or nearly completely in 20 feet. The other 12 feet had short-term or no improvement, with persistent pain and loss of function at 4-5 wk after injection. Of the 20 feet responding to injection, 14 had focal hyperemia on blood-pool images and 6 had minimal extension into the proximal third of the plantar soft tissues. No patient with diffuse hyperemia in the plantar fascia had a response (5/12 feet). On the delayed images of the 20 responders, mild inferior calcaneal uptake was seen in 8 feet, moderate uptake in 6, and severe uptake in 6. These groups did not significantly differ (P > 0.05). The blood-pool studies had good reproducibility, with a kappa-value of 0.64. CONCLUSION: Critical evaluation of plantar blood-pool images provides prognostic information on the response to localized injection into the enthesis. Reporting such studies is simple and reproducible.

Adult↗
PubMed2005

Vessel motion measurement in real-time using movement detection at multiple regions of interest.

A vessel motion detection algorithm has been implemented for the measurement of multiple lymphatic chamber diameters via pre-recorded VHS tape (PAL, 25 Hz). The method differs significantly from previous attempts based on edge-detection, in that it employs center of mass of pixel brightness in the vessel wall based on a Kalman filtered image subtracted from a Kalman filtered background. The operation of the algorithm confirms that it is able to detect accurately the full constriction-relaxation cycle of the vessel and produce data that meets high standards of tolerance. The procedure is well suited for real-time measurement of lymphatic and blood vessel constrictions in vitro or in vivo at multiple sites so long as the object under measurement is sufficiently differentiated from its background.

Algorithms↗