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MR contrast

Rosemarie Forstner, Isabelle Thomassin-Naggara, Teresa Margarida Cunha, Karen Kinkel, Gabriele Marselli, Rahel Kubik-Huch, John A Spencer, Andrea Rockall
: An update of the 2010 published ESUR recommendations of MRI of the sonographically indeterminate adnexal mass integrating functional techniques is provided. An algorithmic approach using sagittal T2 and a set of transaxial T1 and T2WI allows categorization of adnexal masses in one of the following three types according to its predominant signal characteristics. T1 'bright' masses due to fat or blood content can be simply and effectively determined using a combination of T1W, T2W and FST1W imaging...
October 21, 2016: European Radiology
Svetlana V Fedorenko, Svetlana L Grechkina, Asiya R Mustafina, Kirill V Kholin, Alexey S Stepanov, Irek R Nizameev, Ildus E Ismaev, Marsil K Kadirov, Rustem R Zairov, Alfia N Fattakhova, Rustem R Amirov, Svetlana E Soloveva
The present work introduces deliberate synthesis of Gd(III)-doped silica nanoparticles with high relaxivity at magnetic field strengths below 1.5T. Modified microemulsion water-in-oil procedure was used in order to achieve superficial localization of Gd(III) complexes within 40-55nm sized silica spheres. The relaxivities of the prepared nanoparticles were measured at 0.47, 1.41 and 1.5T with the use of both NMR analyzer and whole body NMR scanner. Longitudinal relaxivities of the obtained silica nanoparticles reveal significant dependence on the confinement mode, changing from 4...
October 14, 2016: Colloids and Surfaces. B, Biointerfaces
Soh Youn Suh, Robert A Clark, Alan Le, Joseph L Demer
Purpose: To investigate changes in volumes of extraocular muscle (EOM) compartments in unilateral superior oblique (SO) palsy using magnetic resonance imaging (MRI). Methods: High-resolution, surface-coil MRI was obtained in 19 patients with unilateral SO palsy and 19 age-matched orthotropic control subjects. Rectus EOMs and the SO were divided into two anatomic compartments for volume analysis in patients with unilateral SO palsy, allowing comparison of total compartmental volumes versus controls...
October 1, 2016: Investigative Ophthalmology & Visual Science
Takashi Hashido, Shigeyoshi Saito
PURPOSE: Neuromelanin is a dark pigment granule present within certain catecholamine neurons of the human brain. Here, we aimed to clarify the relationship between contrast of neuromelanin-sensitive magnetic resonance imaging (MRI) and MR relaxation times using T1, T2, and T2* mapping of the lower midbrain. METHODS: The subjects were 14 healthy volunteers (11 men and 3 women, mean age 29.9 ± 6.9 years). Neuromelanin-sensitive MRI was acquired using an optimized T1-weighted two-dimensional (2D)-turbo spin-echo sequence...
2016: PloS One
Paul M Simkin, Natalie Yang, Alpha Tsui, Renate M Kalnins, Greg Fitt, Frank Gaillard
INTRODUCTION: Gemistocytic astrocytoma is the second most common subtype of World Health Organization grade 2 astrocytoma, but has a worse prognosis than other grade 2 lesions. We aim to describe the MR imaging features of histopathologically proven gemistocytic tumours. METHODS: Ethics approval was obtained from both institutions. Patient consent was not required for this retrospective study. We reviewed MR imaging findings of 16 consecutive cases of histopathologically proven gemistocytic astrocytoma and anaplastic astrocytoma with gemistocytic features...
October 21, 2016: Journal of Medical Imaging and Radiation Oncology
Ammara Usman, Umar Sadat, Zhongzhao Teng, Martin J Graves, Jonathan R Boyle, Kevin Varty, Paul D Hayes, Jonathan H Gillard
BACKGROUND: Functional magnetic resonance (MR) imaging of atheroma using contrast media enables assessment of the systemic severity of atherosclerosis in different arterial beds. Whether black-blood imaging has similar ability remains widely unexplored. In this study, we evaluate whether black-blood imaging can differentiate carotid plaques of patients with and without coronary artery disease (CAD) in terms of morphological and biomechanical features of plaque vulnerability, thereby allowing assessment of the systemic severity nature of atherosclerosis in different arterial beds...
October 17, 2016: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
J Wu, S Dehkharghani, F Nahab, J Allen, D Qiu
BACKGROUND AND PURPOSE: Measuring cerebrovascular reactivity with the use of vasodilatory stimuli, such as acetazolamide, is useful for chronic cerebrovascular steno-occlusive disease. The purpose of this study was to evaluate the effects of acetazolamide on the assessment of hemodynamic impairment and functional connectivity by using noninvasive resting-state blood oxygen level-dependent MR imaging. MATERIALS AND METHODS: A 20-minute resting-state blood oxygen level-dependent MR imaging scan was acquired with infusion of acetazolamide starting at 5 minutes after scan initiation...
October 6, 2016: AJNR. American Journal of Neuroradiology
Gavin Low, Harini Dharmana, Samantha Saravana-Bawan, Safwat Girgis
History An asymptomatic 33-year-old woman was referred to the Hepatology Department in 2013 for work-up of indeterminate multifocal liver masses. These lesions were discovered incidentally at multiphase contrast material-enhanced multidetector computed tomography (CT) performed in 2004 to investigate right lower quadrant pain. Imaging surveillance at sporadic intervals revealed slow progressive growth of the lesions over time; however, the number of lesions remained constant. There was no history of cancer, nor were there predisposing factors for chronic liver disease or cirrhosis...
November 2016: Radiology
Yuan Liu, Benoit M Dawant
Deep brain stimulation, as a primary surgical treatment for various neurological disorders, involves implanting electrodes to stimulate target nuclei within millimeter accuracy. Accurate pre-operative target selection is challenging due to the poor contrast in its surrounding region in MR images. In this paper, we present a learning-based method to automatically and rapidly localize the target using multi-modal images. A learning-based technique is applied first to spatially normalize the images in a common coordinate space...
February 2016: ... IEEE-EMBS International Conference on Biomedical and Health Informatics. IEEE-EMBS International Conference on Biomedical and Health Informatics
Takuya Toyonaga, Shigeru Yamaguchi, Kenji Hirata, Kentaro Kobayashi, Osamu Manabe, Shiro Watanabe, Shunsuke Terasaka, Hiroyuki Kobayashi, Naoya Hattori, Tohru Shiga, Yuji Kuge, Shinya Tanaka, Yoichi M Ito, Nagara Tamaki
PURPOSE: Metabolic activity and hypoxia are both important factors characterizing tumor aggressiveness. Here, we used F-18 fluoromisonidazole (FMISO) and F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) to define metabolically active hypoxic volume, and investigate its clinical significance in relation to progression free survival (PFS) and overall survival (OS) in glioblastoma patients. EXPERIMENTAL DESIGN: Glioblastoma patients (n = 32) underwent FMISO PET, FDG PET, and magnetic resonance imaging (MRI) before surgical intervention...
October 18, 2016: European Journal of Nuclear Medicine and Molecular Imaging
J Gallo, N Vasimalai, M T Fernandez-Arguelles, M Bañobre-López
Diagnosis by MRI is frequently non-trivial due to the low sensitivity of the technique. Signal enhancing contrast agents (CAs) are used to aid in the analysis of MR images. We present here a simple protocol for the preparation of responsive CAs based on Mn nanosheets. Mn nanostructures presented here undergo a chemical and structural change in the presence of altered physiological conditions that activate their signal. This strategy allows for a reduction of background, increasing the sensitivity of the technique...
October 18, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Ahmad Chaddad, Camel Tanougast
To isolate the brain from non-brain tissues using a fully automatic method may be affected by the presence of radio frequency non-homogeneity of MR images (MRI), regional anatomy, MR sequences, and the subjects of the study. In order to automate the brain tumor (Glioblastoma) detection, we proposed a novel approach of skull stripping for axial slices derived from MRI. Then, the brain tumor was detected using multi-level threshold segmentation based on histogram analysis. Skull-stripping method, was applied by adaptive morphological operations approach...
March 2016: Brain Informatics
Marcus R Makowski, Christian H P Jansen, Ullrich Ebersberger, Tobias Schaeffter, Reza Razavi, Massimo Mangino, Tim D Spector, Rene M Botnar, Gerald F Greil
OBJECTIVES: The aim of this study was to investigate the impact of BMI on late gadolinium enhancement (LGE) of the coronary artery wall in identical monozygous twins discordant for BMI. Coronary LGE represents a useful parameter for the detection and quantification of atherosclerotic coronary vessel wall disease. METHODS: Thirteen monozygote female twin pairs (n = 26) with significantly different BMIs (>1.6 kg/m2) were recruited out of >10,000 twin pairs (TwinsUK Registry)...
October 14, 2016: European Radiology
Sung Bin Park
Using functional MR imaging techniques, we can approach the functional assessment of gynecologic malignancies. Among them, diffusion-weighted imaging (DWI) and dynamic contrast-enhanced MR imaging (DCE-MRI) are two important techniques. This article provides an overview of functional MR imaging techniques, focusing DWI and DCE-MRI on clinical application in gynecologic malignancies. Functional MR imaging techniques play an important role in detection, characterization, staging, treatment response, and outcome prediction, as well as providing conventional morphologic imaging...
October 14, 2016: Abdominal Radiology
Kousaku Saotome, Akira Matsushita, Koji Matsumoto, Yoshiaki Kato, Kei Nakai, Koichi Murata, Tetsuya Yamamoto, Yoshiyuki Sankai, Akira Matsumura
PURPOSE: A fast spin-echo sequence based on the Periodically Rotated Overlapping Parallel Lines with Enhanced Reconstruction (PROPELLER) technique is a magnetic resonance (MR) imaging data acquisition and reconstruction method for correcting motion during scans. Previous studies attempted to verify the in vivo capabilities of motion-corrected PROPELLER in real clinical situations. However, such experiments are limited by repeated, stray head motion by research participants during the prescribed and precise head motion protocol of a PROPELLER acquisition...
October 11, 2016: Magnetic Resonance Imaging
Chun Yang, Ceng Li, Mengsu Zeng, Xin Lu, Jingjing Li, Jiali Wang, Muhammad Umair Sami, Kai Xu
Non-CE MRA techniques (true steady-state free-precession, SSFP) have been used effectively for the selective visualization of the portal venous system and inferior vena cava. Budd-Chiari Syndrome (BCS) encompasses a number of conditions that cause the obstruction of the hepatic outflow tract from the small hepatic veins to the junction of the inferior vena cava (IVC) and right atrium. The purpose of this study was to diagnose BCS with IVC obstruction using respiratory triggered three-dimensional (3D) true SSFP with T-SLIP and compare to digital subtraction angiography (DSA)...
October 11, 2016: Magnetic Resonance Imaging
Arnav Mehta, Ketan Ghaghada, Srinivasan Mukundan
The first generation of cross-sectional brain imaging using computed tomography (CT), ultrasonography, and eventually MR imaging focused on determining structural or anatomic changes associated with brain disorders. The current state-of-the-art imaging, functional imaging, uses techniques such as CT and MR perfusion that allow determination of physiologic parameters in vivo. In parallel, tissue-based genomic, transcriptomic, and proteomic profiling of brain tumors has created several novel and exciting possibilities for molecular targeting of brain tumors...
November 2016: Magnetic Resonance Imaging Clinics of North America
Jerrold L Boxerman, Mark S Shiroishi, Benjamin M Ellingson, Whitney B Pope
Dynamic susceptibility contrast (DSC) MR imaging, a perfusion-weighted MR imaging technique typically used in neuro-oncologic applications for estimating the relative cerebral blood volume within brain tumors, has demonstrated much potential for determining prognosis, predicting therapeutic response, and assessing early treatment response of gliomas. This review highlights recent developments using DSC-MR imaging and emphasizes the need for technical standardization and validation in prospective studies in order for this technique to become incorporated into standard-of-care imaging for patients with brain tumors...
November 2016: Magnetic Resonance Imaging Clinics of North America
Norihide Yoneda, Osamu Matsui, Azusa Kitao, Kazuto Kozaka, Satoshi Kobayashi, Motoko Sasaki, Kotaro Yoshida, Dai Inoue, Tetsuya Minami, Toshifumi Gabata
Gadoxetic acid is a contrast agent for magnetic resonance (MR) imaging with hepatocyte-specific properties and is becoming increasingly important in detection and characterization of hepatocellular carcinoma and benign hepatocellular nodules, including focal nodular hyperplasia (FNH), nodular regenerative hyperplasia (NRH), hepatocellular adenoma (HCA), and dysplastic nodule. In these hepatocellular nodules, a positive correlation between the grade of membranous uptake transporter organic anion-transporting polypeptide (OATP) 1B3 expression and signal intensity in the hepatobiliary (HB) phase has been verified...
October 14, 2016: Radiographics: a Review Publication of the Radiological Society of North America, Inc
Frank Preiswerk, Matthew Toews, Cheng-Chieh Cheng, Jr-Yuan George Chiou, Chang-Sheng Mei, Lena F Schaefer, W Scott Hoge, Benjamin M Schwartz, Lawrence P Panych, Bruno Madore
PURPOSE: To combine MRI, ultrasound, and computer science methodologies toward generating MRI contrast at the high frame rates of ultrasound, inside and even outside the MRI bore. METHODS: A small transducer, held onto the abdomen with an adhesive bandage, collected ultrasound signals during MRI. Based on these ultrasound signals and their correlations with MRI, a machine-learning algorithm created synthetic MR images at frame rates up to 100 per second. In one particular implementation, volunteers were taken out of the MRI bore with the ultrasound sensor still in place, and MR images were generated on the basis of ultrasound signal and learned correlations alone in a "scannerless" manner...
October 13, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
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