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proton density MRI

Khadija Sheikh, Fumin Guo, Dante P I Capaldi, Alexei Ouriadov, Rachel L Eddy, Sarah Svenningsen, Grace Parraga
PURPOSE: To develop and assess ultrashort echo-time (UTE) magnetic resonance imaging (MRI) biomarkers of lung function in asthma patients. MATERIALS AND METHODS: Thirty participants including 13 healthy volunteers and 17 asthmatics provided written informed consent to UTE and pulmonary function tests in addition to hyperpolarized-noble-gas 3T MRI and computed tomography (CT) for asthmatics only. The difference in MRI signal-intensity (SI) across four lung volumes (full-expiration, functional-residual-capacity [FRC], FRC+1L, and full-inspiration) was determined on a voxel-by-voxel basis to generate dynamic proton-density (DPD) maps...
October 12, 2016: Journal of Magnetic Resonance Imaging: JMRI
Harald Kramer, Perry J Pickhardt, Mark A Kliewer, Diego Hernando, Guang-Hong Chen, James A Zagzebski, Scott B Reeder
OBJECTIVE: The purpose of this study was to prospectively evaluate the accuracy of proton-density fat-fraction, single- and dual-energy CT (SECT and DECT), gray-scale ultrasound (US), and US shear-wave elastography (US-SWE) in the quantification of hepatic steatosis with MR spectroscopy (MRS) as the reference standard. SUBJECTS AND METHODS: Fifty adults who did not have symptoms (23 men, 27 women; mean age, 57 ± 5 years; body mass index, 27 ± 5) underwent liver imaging with un-enhanced SECT, DECT, gray-scale US, US-SWE, proton-density fat-fraction MRI, and MRS for this prospective trial...
October 11, 2016: AJR. American Journal of Roentgenology
Alexandra S Gersing, Benedikt J Schwaiger, Ursula Heilmeier, Gabby B Joseph, Luca Facchetti, Martin Kretzschmar, John A Lynch, Charles E McCulloch, Michael C Nevitt, Lynne S Steinbach, Thomas M Link
OBJECTIVES: To evaluate the ability of different MRI sequences to detect chondrocalcinosis within knee cartilage and menisci, and to analyze the association with joint degeneration. METHODS: Subjects with radiographic knee chondrocalcinosis (n = 90, age 67.7 ± 7.3 years, 50 women) were selected from the Osteoarthritis Initiative and matched to controls without radiographic chondrocalcinosis (n = 90). Visualization of calcium-containing crystals (CaC) was compared between 3D T1-weighted gradient-echo (T1GE), 3D dual echo steady-state (DESS), 2D intermediate-weighted (IW), and proton density (PD)-weighted fast spin-echo (FSE) sequences obtained with 3T MRI and correlated with a semiquantitative CaC score obtained from radiographs...
October 4, 2016: European Radiology
Kazuya Nagatomo, Hidetake Yabuuchi, Yuzo Yamasaki, Hiroshi Narita, Seiji Kumazawa, Tsukasa Kojima, Noriyuki Sakai, Masahumi Masaki, Hiroshi Kimura
OBJECTIVES: To elucidate the utility of PROPELLER for motion artefact reduction on shoulder MRI and to examine the influence of streak artefacts on diagnosis of clinical images. METHODS: 15 healthy volunteers and 48 patients underwent shoulder MRI with/without PROPELLER (coronal oblique proton density-fast spin echo [PD-FSE], sagittal oblique T2-FSE). In a volunteer study, all sequences were performed in both static and exercise-loaded conditions. Two radiologists graded artefacts and delineation of various anatomical structures in the volunteer study and motion and streak artefacts in the clinical study...
October 2016: European Journal of Radiology
E N Unlu, Y Turhan, D M Kos, A A Safak
PURPOSE: The purpose of this study was to evaluate the prevalence of anterior subcutaneous hypersignal indicating edema on proton-density (PD)-weighted MRI of the knee and to determine whether reporting anterior edema is clinically relevant. MATERIALS AND METHODS: One hundred and ninety-one knee MRIs from 162 patients were reviewed for anterior subcutaneous edema. There were 92 men and 70 women with a mean age of 41.72years±13.92 (SD) (range, 15-80years) years and a mean body weight of 75...
September 22, 2016: Diagnostic and Interventional Imaging
T Duval, S Lévy, N Stikov, J Campbell, A Mezer, T Witzel, B Keil, V Smith, L L Wald, E Klawiter, J Cohen-Adad
The myelin g-ratio is defined as the ratio of the inner to the outer diameter of the myelin sheath. This ratio provides a measure of the myelin thickness that complements axon morphology (diameter and density) with high specificity for assessment of demyelination in diseases such as multiple sclerosis. Previous work has shown that an aggregate g-ratio map can be computed using a formula that combines axon and myelin density measured with quantitative MRI. In this work, we computed g-ratio weighted maps in the cervical spinal cord of nine healthy subjects...
September 21, 2016: NeuroImage
Timothy J Colgan, Diego Hernando, Samir D Sharma, Scott B Reeder
PURPOSE: The purpose of this work was to characterize the effects of concomitant gradients (CGs) on chemical shift encoded (CSE)-based estimation of B0 field map, proton density fat fraction (PDFF), and R2*. THEORY: A theoretical framework was used to determine the effects of CG-induced phase errors on CSE-MRI data. METHODS: Simulations, phantom experiments, and in vivo experiments were conducted at 3 Tesla to assess the effects of CGs on quantitative CSE-MRI techniques...
September 21, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Anna E Nidecker, Peter Y Shen
The superb stability and flexibility of the craniovertebral junction (CVJ) are enabled by the ligaments that connect the occipital bone and the C1 and C2 vertebral bodies. Radiographically, these ligaments are best assessed with magnetic resonance imaging (MRI), which has excellent soft tissue contrast, but typically poor spatial resolution. With the advent of advanced MRI techniques, including volumetric sequences, high spatial resolution and contrast resolution can both be attained, allowing for detailed analysis of the ligaments, particularly in trauma settings...
October 2016: Journal of Neurological Surgery. Part B, Skull Base
Prabhakar Rajiah, Mojgan Hojjati, Ziang Lu, Vijaya Kosaraju, Sasan Partovi, James K O'Donnell, Christopher Longenecker, Grace A McComsey, Jackelyn B Golden, Fuad Muakkassa, Scott Santilli, Thomas S McCormick, Kevin D Cooper, Neil J Korman
We report our initial experience of performing integrated PET/MR imaging of the carotid arteries in psoriatic patients. Eleven patients with psoriasis and ten controls underwent carotid PET/MRI. Following injection of the FDG tracer, 3d T1w gradient echo sequence (atMR) was obtained for attenuation correction of PET data. High resolution images of carotid artery were then obtained, including pre-and post-contrast T1-w, T2-w and proton-density images as well as TOF images followed by PET imaging of the torso...
2016: American Journal of Nuclear Medicine and Molecular Imaging
Yanfei Wang, Ivan J Dmochowski
Molecular imaging holds considerable promise for elucidating biological processes in normal physiology as well as disease states, by determining the location and relative concentration of specific molecules of interest. Proton-based magnetic resonance imaging ((1)H MRI) is nonionizing and provides good spatial resolution for clinical imaging but lacks sensitivity for imaging low-abundance (i.e., submicromolar) molecular markers of disease or environments with low proton densities. To address these limitations, hyperpolarized (hp) (129)Xe NMR spectroscopy and MRI have emerged as attractive complementary methodologies...
October 18, 2016: Accounts of Chemical Research
Catherine M Ruoff, Bunita M Eichelberger, Roy R Pool, John F Griffin, Kevin J Cummings, Antonio Pozzi, Abraham Padua, W Brian Saunders
Noninvasive identification of canine articular cartilage injuries is challenging. The objective of this prospective, cadaveric, diagnostic accuracy study was to determine if small field-of-view, three tesla magnetic resonance imaging (MRI) was an accurate method for identifying experimentally induced cartilage defects in canine stifle joints. Forty-two canine cadaveric stifles (n = 6/group) were treated with sham control, 0.5, 1.0, or 3.0 mm deep defects in the medial or lateral femoral condyle. Proton density-weighted, T1-weighted, fast-low angle shot, and T2 maps were generated in dorsal and sagittal planes...
September 14, 2016: Veterinary Radiology & Ultrasound
Peter Y Shen, Anna E Nidecker, Ethan A Neufeld, Paul S Lee, Michelle A James, Andrea S Bauer
BACKGROUND AND PURPOSE: The current prognostic biomarker of functional outcome in brachial plexus birth palsy is serial clinical examination throughout the first 6 months of age. This can delay surgical treatment and prolong parental anxiety in neonates who will recover spontaneously. A potentially superior biomarker is a volumetric proton density MRI performed at clinical presentation and within the first 12 weeks of life, providing a high spatial and contrast resolution examination in 4 minutes...
September 8, 2016: Journal of Neuroimaging: Official Journal of the American Society of Neuroimaging
Yuanjun Teng, Laiwei Guo, Meng Wu, Tianen Xu, Lianggong Zhao, Jin Jiang, Xiaoyun Sheng, Lihu Xu, Bo Zhang, Ning Ding, Yayi Xia
BACKGROUND: Consistent reference data used for anatomic posterior cruciate ligament (PCL) reconstruction is not well defined. Quantitative guidelines defining the location of PCL attachment would aid in performing anatomic PCL reconstruction. The purpose was to characterize anatomic parameters of the PCL tibial attachment based on magnetic resonance imaging (MRI) in a large population of adult knees. METHODS: The PCL tibial attachment site was examined in 736 adult knees with an intact PCL using 3...
2016: BMC Musculoskeletal Disorders
Anahit Grigorian, Larissa McKetton, Keith A Schneider
In albinism, the number of ipsilaterally projecting retinal ganglion cells (RGCs) is significantly reduced. The retina and optic chiasm have been proposed as candidate sites for misrouting. Since a correlation between the number of lateral geniculate nucleus (LGN) relay neurons and LGN size has been shown, and based on previously reported reductions in LGN volumes in human albinism, we suggest that fiber projections from LGN to the primary visual cortex (V1) are also reduced. Studying structural differences in the visual system of albinism can improve the understanding of the mechanism of misrouting and subsequent clinical applications...
2016: Journal of Visualized Experiments: JoVE
Janki Patel, Ricki Bettencourt, Jeffrey Cui, Joanie Salotti, Jonathan Hooker, Archana Bhatt, Carolyn Hernandez, Phirum Nguyen, Hamed Aryafar, Mark Valasek, William Haufe, Catherine Hooker, Lisa Richards, Claude B Sirlin, Rohit Loomba
BACKGROUND: Magnetic resonance imaging-estimated proton-density-fat-fraction (MRI-PDFF) has been shown to be a noninvasive, accurate and reproducible imaging-based biomarker for assessing steatosis and treatment response in nonalcoholic steatohepatitis (NASH) clinical trials. However, there are no data on the magnitude of MRI-PDFF reduction corresponding to histologic response in the setting of a NASH clinical trial. The aim of this study was to quantitatively compare the magnitude of MRI-PDFF reduction between histologic responders versus histologic nonresponders in NASH patients...
September 2016: Therapeutic Advances in Gastroenterology
R Homsi, J Gieseke, J A Luetkens, P Kupczyk, B Maedler, G M Kukuk, F Träber, B Agha, M Rauch, N Rajakaruna, W Willinek, H H Schild, D R Hadizadeh
PURPOSE: To evaluate whether a 3 D proton density-weighted fat-suppressed sequence (PDwFS) of the knee is able to replace multiplanar 2D-PDwFS. MATERIALS AND METHODS: 52 patients (26 men, mean age: 41.9 ± 14.5years) underwent magnetic resonance imaging (MRI) of the knee at 3.0 Tesla using a T/R-coil. The imaging protocol included 3 planes of 2D-PDwFS (acquisition time (AT): 6:40 min; voxel sizes: 0.40 - 0.63 × 0.44 - 0.89 × 3mm³) and a 3D-PDwFS (AT: 6:31 min; voxel size: 0...
October 2016: RöFo: Fortschritte Auf Dem Gebiete der Röntgenstrahlen und der Nuklearmedizin
M J Rivlin, J H Kan, E K Schallert, S P Jadhav, W Zhang, S B Rosenfeld
PURPOSE: Spica magnectic resonance imaging (MRI) is an established technique for postoperative determination of hip reduction in patients treated for developmental dysplasia of the hip (DDH). A hip abduction angle >55° is considered excessive and has been associated with epiphyseal osteonecrosis. Our purpose was to establish objective criteria for measuring hip abduction angles on MRI after hip reduction and spica casting in patients with DDH, and evaluate reproducibility and reliability of angle measurement using these criteria...
October 2016: Journal of Children's Orthopaedics
René-Maxime Gracien, Alina Jurcoane, Marlies Wagner, Sarah C Reitz, Christoph Mayer, Steffen Volz, Stephanie-Michelle Hof, Vinzenz Fleischer, Amgad Droby, Helmuth Steinmetz, Frauke Zipp, Elke Hattingen, Ralf Deichmann, Johannes C Klein
PURPOSE: In secondary progressive Multiple Sclerosis (SPMS), global neurodegeneration as a driver of disability gains importance in comparison to focal inflammatory processes. However, clinical MRI does not visualize changes of tissue composition outside MS lesions. This quantitative MRI (qMRI) study investigated cortical and deep gray matter (GM) proton density (PD) values and T1 relaxation times to explore their potential to assess neuronal damage and its relationship to clinical disability in SPMS...
2016: PloS One
Simeon J S Ruiter, Reinoud W Brouwer, Tim W G M Meys, Cornelis H Slump, Jos J A M van Raay
BACKGROUND: There are two primary surgical techniques to reconstruct the anterior cruciate ligament (ACL), transtibial (TT) technique and anteromedial portal (AMP) technique. Currently, there is no consensus which surgical technique elicits the best clinical and functional outcomes. MRI-derived measures of the signal intensity (SI) of the ACL graft have been described as an independent predictor of graft properties. The purpose of this study is to compare the MRI derived SI measurements of the ACL graft one year after ACL reconstruction, in order to compare the outcomes of both the AMP and TT ACL reconstruction technique...
2016: BMC Musculoskeletal Disorders
Lauri Koivula, Leonard Wee, Juha Korhonen
PURPOSE: Magnetic resonance imaging (MRI) is increasingly used for radiotherapy target delineation, image guidance, and treatment response monitoring. Recent studies have shown that an entire external x-ray radiotherapy treatment planning (RTP) workflow for brain tumor or prostate cancer patients based only on MRI reference images is feasible. This study aims to show that a MRI-only based RTP workflow is also feasible for proton beam therapy plans generated in MRI-based substitute computed tomography (sCT) images of the head and the pelvis...
August 2016: Medical Physics
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