Super-Resolution in Respiratory Synchronized Positron Emission Tomography

Abstract

Abstract-Respiratorymotion is a major source of reduced quality in positron emission tomography (PET). In order to minimize its effects, the use of respiratory synchronized acquisitions, leading to gated frames, has been suggested. Such frames, however, are of low signal-to-noise ratio (SNR) as they contain reduced statistics. Super-resolution (SR) techniques make use of the motion in a sequence of images in order to improve their quality. They aim at enhancing a low-resolution image belonging to a sequence of images representing different views of the same scene. In this work, a maximum a posteriori (MAP) super-resolution algorithm has been implemented and applied to respiratory gated PET images for motion compensation. An edge preserving Huber regularization term was used to ensure convergence. Motion fields were recovered using a B-spline based elastic registration algorithm. The performance of the SR algorithm was evaluated through the use of both simulated and clinical datasets by assessing image SNR, as well as the contrast, position and extent of the different lesions. Results were compared to summing the registered synchronized frames on both simulated and clinical datasets. The super-resolution image had higher SNR (by a factor of over 4 on average) and lesion contrast (by a factor of 2) than the single respiratory synchronized frame using the same reconstruction matrix size. In comparison to the motion corrected or the motion free images a similar SNR was obtained, while improvements of up to 20% in the recovered lesion size and contrast were measured. Finally, the recovered lesion locations on the SR images were systematically closer to the true simulated lesion positions. These observations concerning the SNR, lesion contrast and size were confirmed on two clinical datasets included in the study. In conclusion, the use of SR techniques applied to respiratory motion synchronized images lead to motion compensation combined with improved image SNR and contrast, without any increase in the overall acquisition times. Index Terms-Four-dimensional(4-D) positron emission tomography, respiratory motion, super-resolution.

Statistical evaluation of PET motion correction methods using MR derived motion fields

“…Resolution enhancement during MCIR has been recently reported by several groups [12]. Recently, Wallach et al proposed regularized super resolution reconstruction for motion compensation [26].…”

Advances in Biomedical Imaging and Image Fusion

“…A PET provides the functional information of organs and tissues. PET scans are very helpful in detection and treatment planning of Epilepsy, Alzheimer's disease, lung and liver cancer and breast cancer and Heart diseases [40][41][42][43][44][45][46]. early stage and the radio tracer used is very safe since it does not involve any kind of radiation [47].…”

Temperature correction in super-resolution reconstruction of thermograms

“…Depending on the method used, not only unknown thermopixels but also those present in the input image. Considered methods are well known and widely applied for the visible light images: Robust Superresolution (RS) [5], Iterative Back Projection (IBP) [6] and two-dimensional interpolation (ITP). Unfortunately in presented SR methods know values of pixels were changed so is necessary to correcting values of all pixels based on information from sources images.…”