A Method for Fluorescent Diffuse Optical Tomography Based on Lattice Boltzmann Forward Model on GPU Parallelization / 中国医疗器械杂志

Fluorescent Diffuse Optical Tomography (FDOT) is an emerging imaging method with great prospects in fields of biology and medicine. However, the current solutions to the forward problem in FDOT are time consuming, which greatly limit the application. We proposed a method for FDOT based on Lattice Boltzmann forward model on GPU to greatly improve the computational efficiency. The Lattice Boltzmann Method (LBM) was used to construct the optical transmission model. This method separated the LBM into collision, streaming and boundary processing processes on GPUs to perform the LBM efficiently, which were local computational and inefficient on CPU. The feasibility of the proposed method was verified by the numerical phantom and the physical phantom experiments. The experimental results showed that the proposed method achieved the best performance of a 118-fold speed up under the precondition of simulation accuracy, comparing to the diffusion equation implemented by Finite Element Method (FEM) on CPU. Thus, the LBM on the GPU may efficiently solve the forward problem in FDOT.

Relación estructura función en la detección de daño retinal por cloroquina / Relation of structure and function in detecting the retinal damage due to chloroquine

Objetivo: determinar la utilidad de la microperimetría y la tomografía óptica coherente en la detección de daño retinal subclínico por cloroquina. Métodos: estudio prospectivo, observacional y analítico en pacientes consumidores de cloroquina, atendidos en la consulta de Neuroftalmología del Instituto Cubano de Oftalmología Ramón Pando Ferrer, entre septiembre 2010 y octubre 2011. Fueron incluidos 44 ojos. Se realizaron exámenes para evaluar función (psicofísica visual y microperimetría) y estructura (biomicroscopia y tomografía óptica coherente). Resultados: la edad promedio fue de 43 años con una dosis acumulada de cloroquina de 182 g y un tiempo de consumo inferior a cinco años. Existió relación significativa entre la dosis acumulada y las variables siguientes: visión del color (-0,495; p= 0,001), grosor retinal peripapilar temporal (-0,353; p= 0,019) e inferior (-0,336; p= 0,026), macular central (-0,652; p= 0,000) y sensibilidad retinal por microperimetría (-0,436; p= 0,003) con alteraciones funcionales y estructurales en relación con el incremento de la dosis acumulada. Conclusiones: se demostró que es posible detectar daño retinal funcional temprano mediante microperimetría y tomografía óptica coherente en pacientes consumidores de cloroquina, en presencia de otros estudios funcionales y biomicroscopia normales. Unido a la tomografía óptica coherente el microperímetro puede constituir una útil herramienta para pesquisa de toxicidad retiniana

Objective: to determine the usefulness of microperimetry and of the optical coherence tomography in the detection of subclinical retinal damage due to chloroquine. Methods: prospective, observational and analytical study in patients taking chloroquine, who were seen at the Neuro-ophthalmology service of "Ramón Pando Ferrer" Institute of Ophthalmology from September 2010 through October 2011. Forty four eyes were included. Tests were performed to assess function (visual psychophysics and microperimetry) and structure (biomicroscopy and optical coherence tomography). Results: mean age was 43 years with a cumulative dose of 182 g and less than 5 years taking this drug. There was significant correlation between the cumulative dose of chloroquine and the following variables: color vision (-0.495, p = 0.001), temporal peripapillary retinal thickness (-0.353, p= 0.019) and lower (-0.336, p = 0.026), central macular (-0.652, p = 0.000) and retinal sensitivity by microperimetry (-0.436, p= 0.003) with functional and structural changes related to the increase in cumulative dose. Conclusions: it was demonstrated that it is possible to detect early functional retinal damage by using microperimetry and optical coherence tomography in patients taking chloroquine, despite normal results of other functional studies and of biomicroscopy. The combination of microperimetry and optical coherence tomography may be a useful screening tool for retinal toxicity

Estudo das correlações entre a área do disco óptico e as características geométricas e biomecânicas da córnea / Study of correlation between optic disc size and corneal geometry and biomechanics

OBJETIVO: Correlacionar área do disco óptico com parâmetros geométricos e biomecânicos da córnea. MÉTODOS: Estudo retrospectivo nos arquivos de pacientes do Instituto de Olhos Renato Ambrósio a fim de se identificar os pacientes que realizaram exames HRT (Heidelberg Retina Tomography), Pentacam e ORA. A retinografia digital foi revisada de modo a se classificar na escala DDLS (Disc Damage Likelihood Scale). RESULTADOS: 244 olhos de 122 pacientes (75 mulheres) foram incluídos no estudo. A média de idade foi de 47,2 anos (de 8 a 97 anos, desvio padrão de 21,7). Não houve correlação significante entre área do disco e nenhuma das medidas de PIO (IOPg, IOPcc). Encontrou-se uma relação negativa significativa com CRF (r=-0,1337, p=0,0263). A relação com histerese foi também negativa (-0,1123), mas o valor p foi maior que 0,05 (0,0625). Não houve correlação significante entre área do disco e progressão paquimétrica mínima ou média. Entretanto, observou-se correlação significante e positiva entre a área do disco e astigmatismo corneano (Delta K), sendo de 1,15 (p=0,0129). CONCLUSÃO: Existe uma correlação negativa entre a área do disco óptico e os parâmetros biomecânicos e estruturais da córnea. Tal correlação pode ser parte da explicação da córnea ser um fator de risco para maior susceptibilidade do nervo óptico para neuropatia glaucomatosa.

PURPOSE: To correlate optic disc size geometry, corneal architecture and biomechanics. METHODS: Optic disc area and geometry was accessed by HRT III (Heidelberg Retina Tomography - Heidelberg eng), Pentacam (Oculus) was used for accessing IOP and corneal parameters and ORA (Ocular Response Analyze - Reichert) was utilized to access corneal biomechanical properties. Classification based DDLS (Disc Damage Likelihood Scale) scale from retinography was performed. Settings: Instituto de Olhos Renato Ambrósio. RESULTS: 244 eyes of 122 patients (75 female) were included. The average age was 47,2 years (from 8 to 97 years). A significant negative correlation was found between disc optic size and CRF (r=0,1337, p=0,0263). A small trend was also found between optic nerve size and hysteresis (r=-0,1123, p=0,0625). A significant negative correlation was also found between disc optic size and thinnest point, maximal pachymetri progression, corneal volume at (1, 4 e 6mm) and difference from thinnest and central value (p<0,05). The highest negative correlation was with corneal volume within 4mm in diameter (r=-1,887; p=0,0017). A positive correlation between size of optic disc and cornea astigmatism (delta K), was found (r= 1,15; p=0,0129). CONCLUSION: There is a negative correlation between optic disc size and corneal thickness and biomechanical properties. These findings may help explaining susceptibility for the development of glaucoma neuropathy in some cases.

Trabeculectomy and optic nerve head topography

The objective of the present study was to evaluate changes in optic nerve head parameters, measured by confocal laser tomography, before and after trabeculectomy in order to identify outcome measures for the management of glaucoma. The optic nerve head of 22 eyes (22 patients) was analyzed by confocal laser tomography with the Heidelberg retinal tomogram (HRT) before and after trabeculectomy. The median time between the first HRT and surgery was 4.6 months (mean: 7.7 ± 8.3) and the median time between surgery and the second HRT was 10.8 months (mean: 12.0 ± 6.8). The patients were divided into two groups, i.e., those with the highest (group A) and lowest (group B) intraocular pressure (IOP) change after surgery. Differences in the 12 standard topographic parameters before and after surgery for each group were evaluated by the Wilcoxon signed rank test and the differences in these parameters between the two groups were compared by the Mann-Whitney rank sum test. Multiple regression analysis was used to evaluate the influence of the change in IOP (deltaIOP and deltaIOP percent) and the changes in the other parameters. There were significant differences in the HRT measures before and after surgery in group A only for cup volume. In group B, no parameter was statistically different. The changes in group A were not significantly different than those in group B for any parameter (P > 0.004, Bonferroni correction for multiple comparisons). deltaIOP and deltaIOP percent had a statistically significant effect on delta cup disk area, delta cup volume and delta mean cup depth. Changes in cup shape size were influenced significantly only by deltaIOP. Some optic disc parameters measured by HRT presented a significant improvement after filtering surgery, depending on the amount of IOP reduction. Long-term studies are needed to determine the usefulness of these findings as outcome measures in the management of glaucoma.