Análisis de la cuantifiación tridimensional de las vías lagrimales en tomografía computarizada

La descripción de la anatomía del sistema de drenaje lagrimal en la literatura es poco precisa. Se han realizado mediciones del canal nasolagrimal óseo (CNLO) en cadáver, radiografía y tomografía computarizada (TC). JUSTIFICACIÓN, HIPÓTESIS DE TRABAJO Y OBJETIVOS Hasta ahora, todas las mediciones realizadas sobre imágenes tienen al menos un paso manual, lo que inevitablemente degrada la fiabilidad de los datos obtenidos. La mayoría de las mediciones realizadas en TC son bidimensionales y únicamente en unos pocos niveles del canal; y las que son tridimensionales presentan algún paso manual. Se han publicado resultados contradictorios sobre la relación entre las dimensiones en TC del canal nasolagrimal óseo y la patología obstructiva del sistema de drenaje lagrimal, que obligan a revisar la calidad de las mediciones en las que se basan..

Roughness of retinal layers in Alzheimer’s disease

There is growing evidence that thinned retinal regions are interspersed with thickened regions in all retinal layers of patients with Alzheimer’s disease (AD), causing roughness to appear on layer thickness maps. The hypothesis is that roughness of retinal layers, assessed by the fractal dimension (FD) of their thickness maps, is an early biomarker of AD. Ten retinal layers have been studied in macular volumes of optical coherence tomography from 24 healthy volunteers and 19 patients with mild AD (Mini-Mental State Examination 23.42 ± 3.11). Results show that FD of retinal layers is greater in the AD group, the differences being statistically significant (p < 0.05). Correlation of layer FD with cognitive score, visual acuity and age reach statistical significance at 7 layers. Nearly all (44 out of 45) FD correlations among layers are positive and half of them reached statistical significance (p < 0.05). Factor analysis unveiled two independent factors identified as the dysregulation of the choroidal vascular network and the retinal inflammatory process. Conclusions: surface roughness is a holistic feature of retinal layers that can be assessed by the FD of their thickness maps and it is an early biomarker of AD

Spatial analysis of thickness changes in ten retinal layers of Alzheimer’s disease patients based on optical coherence tomography

The retina is an attractive source of biomarkers since it shares many features with the brain. Thickness differences in 10 retinal layers between 19 patients with mild Alzheimer’s disease (AD) and a control group of 24 volunteers were investigated. Retinal layers were automatically segmented and their thickness at each scanned point was measured, corrected for tilt and spatially normalized. When the mean thickness of entire layers was compared between patients and controls, only the outer segment layer of patients showed statistically significant thinning. However, when the layers were compared point-by point, patients showed statistically significant thinning in irregular regions of total retina and nerve fiber, ganglion cell, inner plexiform, inner nuclear and outer segment layers. Our method, based on random field theory, provides a precise delimitation of regions where total retina and each of its layers show a statistically significant thinning in AD patients. All layers, except inner nuclear and outer segments, showed thickened regions. New analytic methods have shown that thinned regions are interspersed with thickened ones in all layers, except inner nuclear and outer segments. Across different layers we found a statistically significant trend of the thinned regions to overlap and of the thickened ones to avoid overlapping

Occult Orbital Injury with Dagger Fragment with Resulting Pneumocephalus

Penetrating injuries of the cranium are relatively uncommon, only 0.4% of all head injuries. In patients with disturbed conscious level, an extensive examination should be performed in the emergency unit to rule out transorbital penetrating brain injury. A 25-year-old male was attacked with a dagger. He presented with ethylic intoxication and the physical examination demonstrated a small skin injury on the lateral canthus of the left eye with a large periocular hematoma which prevented eyelid opening. Cranial CT scan showed a metallic intraorbital foreign body consisting of a fragment of a dagger which perforated the eyeball, and penetrated through the superomedial wall of the orbit into the anterior cranial fossa. Reconstruction of the eyeball was performed and the fragment was removed. Orbital injuries with a knife in situ are very unusual. Early identification and removal of retained foreign bodies are essential