Contrast-to-noise ratio is a useful predictor of early displacement of large submacular hemorrhage by intravitreal SF6 gas injection

Retina ◽  
2021 ◽  
Vol Publish Ahead of Print ◽  
Author(s):  
Sawako Ura ◽  
Manabu Miyata ◽  
Sotaro Ooto ◽  
Satoshi Yasuhara ◽  
Hiroshi Tamura ◽  
...  
PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243201
Author(s):  
Jun Hyun Lim ◽  
Yong Seop Han ◽  
Sang Joon Lee ◽  
Ki Yup Nam

Purpose We investigated risk factors for breakthrough vitreous hemorrhage (VH) after an intravitreal tissue plasminogen activator (tPA) and gas injection in patients with submacular hemorrhage (SMH) associated with age-related macular degeneration (AMD). Methods The medical records of patients diagnosed with SMH associated with AMD who received an intravitreal tPA (50 μg/0.05 mL) and perfluoropropane gas (0.3 mL) injection were reviewed retrospectively. We analyzed the associations of breakthrough VH with age, sex, best-corrected visual acuity, intraocular pressure, AMD subtype, accompanying sub-retinal pigment epithelium (RPE) hemorrhage, history of cataract surgery, history of hypertension and diabetes mellitus, history of drinking and smoking, and history of antiplatelet or anticoagulant medication. We also examined the relationships between various parameters, including the area ratio of the SMH to the optic disc (AHD) and the height of the SMH obtained from optical coherence tomography. Results In total, 52 eyes from 52 patients were enrolled in this study; 16 eyes (30%) showed breakthrough VH. The proportions of patients with a current smoking history were 75.0% in the VH group and 22.2% in the non-VH group (p = 0.010). Other factors did not differ significantly between the two groups. The proportion of cases with accompanying sub-RPE hemorrhage was 50.0% and 58.3% in the VH and non-VH groups, respectively (p = 0.763). The AHD (p = 0.001) and SMH height (p < 0.001) were significantly greater in the VH group. In a receiver operating characteristic curve analysis, the cut-off values of AHD and SMH height were 20.1 and 1208 μm, respectively. According to logistic regression analysis, when the AHD and SMH height were greater than the individual cut-off values, the odds ratio of VH increased by 10.286 fold (95% confidence interval [CI], 2.452–43.148; p = 0.001) and 75.400 fold (95% CI, 7.991–711.441; p < 0.001), respectively, with respect to their respective reference groups (less than the cut-off value). Among the significant factors associated with VH occurrence, including current smoking, AHD, and SMH height, only current smoking and SMH height were found to be significant in multiple regression analysis (p = 0.040, 0.016). Conclusions The incidence of breakthrough VH was significantly higher in those with current smoking status and for SMH with a larger AHD and greater height. The height of the SMH was more predictable of the possibility of VH than AHD.


2003 ◽  
Vol 218 (1) ◽  
pp. 64-69 ◽  
Author(s):  
Detlef Holland ◽  
Burkhard Wiechens

1999 ◽  
Vol 96 (10) ◽  
pp. 643-647 ◽  
Author(s):  
Petra Meier ◽  
Christian Zeumer ◽  
Claudia Jochmann ◽  
Peter Wiedemann

2016 ◽  
Vol 2016 ◽  
pp. 1-4
Author(s):  
Takayuki Tsuyama ◽  
Hiroshi Hirose ◽  
Tomohiro Hattori

Background. Submacular hemorrhage can occur after blunt trauma to the eye. Intravitreal tissue plasminogen activator (tPA) and gas injection are often used for treatment and are effective for submacular hemorrhage caused by age-related macular degeneration. This report describes the clinical outcome in a child with submacular hemorrhage caused by traumatic choroidal rupture who underwent successful intravitreal tPA injection and pneumatic displacement.Case Presentation. A 10-year-old boy developed sudden decrease of vision and a central scotoma in his right eye after trauma. Submacular hemorrhage was found in the eye. Visual acuity was 20/70 OD. Tissue plasminogen activator (12.5 μg in 0.05 mL) and 0.3 mL of pure sulfur hexafluoride were injected into the vitreous cavity under general anesthesia. After surgery, the patient was instructed to maintain a prone position. Displacement of the submacular hemorrhage from the fovea revealed a choroidal rupture, presumed to be the cause of the hemorrhage. After 4 months of follow-up, visual acuity was restored and final visual acuity is 20/16.Conclusion. Intravitreal tPA and gas injection can be an effective treatment for children with submacular hemorrhage.


Author(s):  
R. F. Egerton

An important parameter governing the sensitivity and accuracy of elemental analysis by electron energy-loss spectroscopy (EELS) or by X-ray emission spectroscopy is the signal/noise ratio of the characteristic signal.


Author(s):  
David A. Grano ◽  
Kenneth H. Downing

The retrieval of high-resolution information from images of biological crystals depends, in part, on the use of the correct photographic emulsion. We have been investigating the information transfer properties of twelve emulsions with a view toward 1) characterizing the emulsions by a few, measurable quantities, and 2) identifying the “best” emulsion of those we have studied for use in any given experimental situation. Because our interests lie in the examination of crystalline specimens, we've chosen to evaluate an emulsion's signal-to-noise ratio (SNR) as a function of spatial frequency and use this as our critereon for determining the best emulsion.The signal-to-noise ratio in frequency space depends on several factors. First, the signal depends on the speed of the emulsion and its modulation transfer function (MTF). By procedures outlined in, MTF's have been found for all the emulsions tested and can be fit by an analytic expression 1/(1+(S/S0)2). Figure 1 shows the experimental data and fitted curve for an emulsion with a better than average MTF. A single parameter, the spatial frequency at which the transfer falls to 50% (S0), characterizes this curve.


Author(s):  
W. Kunath ◽  
K. Weiss ◽  
E. Zeitler

Bright-field images taken with axial illumination show spurious high contrast patterns which obscure details smaller than 15 ° Hollow-cone illumination (HCI), however, reduces this disturbing granulation by statistical superposition and thus improves the signal-to-noise ratio. In this presentation we report on experiments aimed at selecting the proper amount of tilt and defocus for improvement of the signal-to-noise ratio by means of direct observation of the electron images on a TV monitor.Hollow-cone illumination is implemented in our microscope (single field condenser objective, Cs = .5 mm) by an electronic system which rotates the tilted beam about the optic axis. At low rates of revolution (one turn per second or so) a circular motion of the usual granulation in the image of a carbon support film can be observed on the TV monitor. The size of the granular structures and the radius of their orbits depend on both the conical tilt and defocus.


Sign in / Sign up

Export Citation Format

Share Document