Gaspar Delso

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UNLABELLED Attenuation correction (AC) of whole-body PET data in combined PET/MRI tomographs is expected to be a technical challenge. In this study, a potential solution based on a segmented attenuation map is proposed and evaluated in clinical PET/CT cases. METHODS Segmentation of the attenuation map into 4 classes (background, lungs, fat, and soft(More)
UNLABELLED The recently released Biograph mMR is the first commercially available integrated whole-body PET/MR scanner. There are considerable advantages to integrating both modalities in a single scanner that enables truly simultaneous acquisition. However, there are also concerns about the possible degradation of both PET and MR performance in an(More)
The combination of magnetic resonance imaging (MR) and positron emission tomography (PET) scanners can provide a powerful tool for clinical diagnosis and investigation. Among the challenges of developing a combined scanner, obtaining attenuation maps for PET reconstruction is of critical importance. This requires accounting for the presence of MR hardware(More)
Positron emission tomography-computed tomography (PET-CT) is superior compared to stand-alone PET in evaluation of malignancies. Few studies have employed high-resolution structural information to correct PET. We designed a semiautomatic algorithm using CT and PET to obtain a partial volume corrected (PVC) standardized uptake value (SUV) and a combined(More)
UNLABELLED MR-based attenuation correction is instrumental for integrated PET/MR imaging. It is generally achieved by segmenting MR images into a set of tissue classes with known attenuation properties (e.g., air, lung, bone, fat, soft tissue). Bone identification with MR imaging is, however, quite challenging, because of the low proton density and fast(More)
The combination of clinical MRI and PET systems has received increased attention in recent years. In contrast to currently used PET/CT systems, PET/MRI offers not only improved soft-tissue contrast and reduced levels of ionizing radiation, but also a wealth of MRI-specific information such as functional, spectroscopic and diffusion tensor imaging. Combining(More)
UNLABELLED Ultrashort-echo-time (UTE) sequences have been proposed in the past for MR-based attenuation correction of PET data, because of their ability to image cortical bone. In the present work we assessed the limitations of dual-echo UTE imaging for bone segmentation in head and neck imaging. Sequentially acquired MR and PET/CT clinical data were used(More)
The aim of this paper is to develop a registration methodology in order to combine anatomical and functional information provided by thoracic/abdominal computed tomography (CT) and whole-body positron emission tomography (PET) images. The proposed procedure is based on the incorporation of prior anatomical information in an intensity-based nonrigid(More)
Among the proposed system architectures capable of delivering positron emission tomography/magnetic resonance (PET/MR) datasets, tri-modality systems open an interesting field in which the synergies between these modalities can be exploited to address some of the problems encountered in standalone systems. In this paper we present a feasibility study of the(More)
UNLABELLED Attenuation correction (AC) for integrated PET/MR imaging in the human brain is still an open problem. In this study, we evaluated a simplified atlas-based AC (Atlas-AC) by comparing (18)F-FDG PET data corrected using either Atlas-AC or true CT data (CT-AC). METHODS We enrolled 8 patients (median age, 63 y). All patients underwent clinically(More)