Observation on the optimal brakingtime for ultrasonography of traumatic lipohemarthosis

Objective To investigate the braking time in diagnosis of lipohemarthrosis by ultrasound. Methods Experiment group:After 20 tubes containing fresh blood and pig marrow were uniformly mixed, they were instantly continuously detected by high-frequency linear array transducer in fixed-area at short-interval.Clinical group: Ten walking patients with lipohemarthrosis were examined with continuous detection by ultrasound,CT and MR before operation.Results Experiment group: Cloudy echo and slowly floating up of lipoids were detected at the beginning.After 2.7 to 3.7 minutes (average 3.17 minutes), the liquid was divided into two layers with vague boundary.After 5.3 to 8.0 minutes (average 6.75 minutes) ,the liquid was divided into 3 layers with thickening serum laye.Clinical group: Ultrasound findings: Cloudy medium echo was detected at first.After 2.0 to 4.0 minutes (average 3.08 minutes),the liquid was divided into two layers.After 4.4 to 10.0 minutes (average 6.92 minutes) , the liquid was divided into 3 layers with thickening serum layers.Three knees showed fracture line and 2 knees with occult fracture were diagnosed as lipohemarthrosis.CT and MR findings: Ten knees showed fracture line in CT examination,of which 7 knees showed double liquid-liquid layer and 3 knees showed single liquid-liquid layer in the suprapatellar bursa.Ten knees showed fracture line in MR examination,6 knees showed double liquid-liquid layer and 4 knees showed single liquid-liquid layer in the suprapatellar bursa. Conclusions The best braking time in diagnosing lipohemarthrosis by ultrasound can be shorten to 10 minutes and the necessary braking time is 2 to 4 minutes. Key words: Ultrasonography;  Lipohemarthrosis; Braking time