Interval-based reconstruction for uncertainty quantification in PET.

A new directed interval-based tomographic reconstruction algorithm, called non-additive interval based expectation maximization (NIBEM) is presented. It uses non-additive modeling of the forward operator that provides intervals instead of single-valued projections. The detailed approach is an extension of the maximum likelihood-expectation maximization algorithm based on intervals. The main motivation for this extension is that the resulting intervals have appealing properties for estimating the statistical uncertainty associated with the reconstructed activity values. After reviewing previously published theoretical concepts related to interval-based projectors, this paper describes the NIBEM algorithm and gives examples that highlight the properties and advantages of this interval valued reconstruction.

Functional and high-resolution retinal imaging monitoring photoreceptor damage in acute macular neuroretinopathy.

BACKGROUND: To report functional and high-resolution retinal imaging abnormalities, including adaptive optics (AO) throughout the course of acute macular neuroretinopathy (AMNR). METHODS: Two female patients (four eyes) with a diagnosis of AMNR were observed at the Clinical Investigation Center, CHNO des Quinze-Vingts, Paris, France. The patients underwent detailed ophthalmic examination including best-corrected visual acuity, slit-lamp examination, kinetic and static perimetry, full-field and multifocal electroretinogram, infrared reflectance, autofluorescence imaging and spectral-domain optical coherence tomography (SD-OCT) and AO fundus imaging at presentation and during follow-up. RESULTS: Both cases showed concomitant loss of integrity of the outer retinal structures on SD-OCT, and marked abnormalities on AO imaging with disruption of the visibility of the cone mosaic. In the first case, photoreceptor damage was seen to progress during several weeks before healing. In both cases, there were persistent morphological abnormalities of photoreceptors 1 year after onset. CONCLUSION: This study further highlights the value of AO fundus imaging to facilitate detection, mapping, and monitoring of damage to the cone outer segments during AMNR. In particular, residual damage to the cone mosaic can be precisely documented.