background: one of the challenges of pet/mri combined systems is to derive an attenuation map to correct the pet image. for that, the pseudo-ct image could be used to correct the attenuation. until now, most existing scientific researches construct this pseudo-ct image using the registration techniques. however, these techniques suffer from the local minima of the non-rigid deformation energy f...

Background: One of the challenges of PET/MRI combined systems is to derive an attenuation map to correct the PET image. For that, the pseudo-CT image could be used to correct the attenuation. Until now, most existing scientific researches construct this pseudo-CT image using the registration techniques. However, these techniques suffer from the local minima of the non-rigid deformation energy f...

BACKGROUND In order to benefit from the highly conformal irradiation of tumors in ion radiotherapy, sophisticated treatment planning and simulation are required. The purpose of this study was to investigate the potential of MRI for ion radiotherapy treatment plan simulation and adaptation using a classification-based approach. METHODS Firstly, a voxelwise tissue classification was applied to ...

An alternative pseudo CT generation method for magnetic resonance image (MRI)-based radiotherapy planning was investigated in the work. A pseudo CT was initially generated using the rigid image registration between the planning MRI and previously acquired diagnostic CT scan. The pseudo CT generated was then refined to have the same morphology with that of the referenced planning image scan by a...

BACKGROUND AND PURPOSE High-attenuation areas (HDAs) called pseudo-subarachnoid hemorrhages (SAHs) may develop in some patients resuscitated from cardiopulmonary arrest (CPA), though no hemorrhage has occurred. We investigated the imaging characteristics and clinical significance of this phenomenon. MATERIALS AND METHODS CT images of consecutive patients resuscitated from nontraumatic CPA wer...

Introduction: Despite growing interest in the use of magnetic resonance imaging (MRI) in the external radiotherapy design process (RT), Computer Tomography (CT) remains a gold standard and is regarded as a basic imaging modality in radiotherapy. MRI shows the high contrast in soft tissues without any radiation exposure to patients. As a result, MRI is used in functional tissue ...

Translational Imaging Group, Centre for Medical Image Computing, University College London, London, UK In this work, we propose to tackle the problem of attenuation correction in the head and neck by synthesising CT from MR images using an iterative multi-atlas approach. The proposed method relies on pre-acquired T2-weighted MRI and CT images of the neck. For each subject, the MRI is non-rigidl...

AIM Respiratory motion affects cardiac PET-computed tomography (CT) imaging by reducing attenuation correction (AC) accuracy and by introducing blur. The aim of this study was to compare three approaches for reducing motion-induced AC errors and evaluate the inclusion of respiratory motion correction. MATERIALS AND METHODS AC with a helical CT was compared with averaged cine and gated cine CT...

behcet’s disease is a rare immune mediated systemic vasculitis which besides it’s more frequent involvement of eyes and skin,   sometimes present with aortic pseudo aneurysm and more rarely cardiac inflammatory masses.a 51-year-old patient with behçet’s disease presented with two symptomatic aortic pseudoaneurysms concomitant with a right atrial mass. computed tomography (ct) revealed one supra...

a pseudo aneurysm results from leakage of blood from an artery after trauma or dehiscence or separation of a surgical anastomosis. the reported rate of pseudo aneurysm in access sites range from 0.88% to 8%. it has some cause like penetrating trauma, blunt trauma and endovascular procedure. the differential diagnoses of this lesion are hematoma, av fistula, lymphadenopathy, lymphocele, dvt, com...