米山 博喜, 山田 利津子, 太根 節直

Hiroki YONEYAMA, Ristuko YAMADA, Sadanao Tane

聖マリアンナ医科大学眼科学教室

Department of Ophthalmology, St. Marianna University School of Medicine

キーワード : Retinal detachment, Vitreous membrane, Sensitivity-graded tomography, Kinetic echography, Image-net

Ultrasonographic diagnosis of intravitreal membranous structures has been evaluated by topographic, quantitative, and kinetic echography. Quantitative echography has been performed on 24 eyes with retinal detachment and 24 eyes with vitreous membrane formation by Ophthascan-S (Biophysic medical) and Ophthasonic A/B scan (Techner). The value of Δ dB have been the difference (Δ) between the tissue sensitivity setting (72 dB) and the sensitivity setting necessary to eliminate the membrane spike. The Δ dB of detached retinas and vitreous membranes have been found to be 20.3±6.7 (average±standard deviation) dB and 7.4±7.8 dB, respectively. Kinetic echography has been performed on 6 eyes featuring retinal detachment and 6 eyes with a vitreous membrane. Sequential ultrasonic images separated in time by 0.04 seconds have been recorded on videotape, after the patients moved their eyes rotating 40 degrees up and down to induce motion. Distances of 1 mm between every point on the membrane from the optic disk, and intervals between such points and the nearest points on the inner wall have been measured on the traced sequential images. The three-dimensional image-nets have been displayed the distance from the disk to every point on the membrane and intervals from those points to the inner wall against time. Differences in the distances between subsequent ultrasonic images have been used to calculate the velocity and acceleration. As a result, the detached retina has been moving as a continuous, regular-traveling wave, and the average velocity and acceleration of after movements has been found to be 17.1±18.1 mm/sec and 353.0±353.2 mm/sec². The vitreous membrane has been moving in an interrupted, and irregular way, and the average velocity and acceleration of movements has been found to be 27.0±23.0 mm/sec and 526.3±491.7 mm/sec², respectively, which are significantly (p