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Magnetic resonance physics

Xiaolong Liu, Yiran Xia, Lulu Liu, Dongmei Zhang, Zhaosheng Hou
The purpose of this study is to offer a novel kind of polyurethane with improved surface blood compatibility for long-term implant biomaterials. In this work, the aliphatic poly(ester-urethane) (PEU) with uniform-size hard segments was prepared and the PEU surface was grafted with hydrophilic poly(ethylene glycol) (PEG). The PEU was obtained by chain-extension of poly(ɛ-caprolactone) (PCL) with isocyanate-terminated urethane triblock. Free amino groups were introduced onto the surface of PEU film via aminolysis with hexamethylenediamine, and then the NH2 -grafted PEU surfaces (PEU-NH2 ) were reacted with isocyanate-terminated monomethoxyl PEG (MPEG-NCO) to obtain the PEG-grafted PEU surfaces (PEU-PEG)...
January 1, 2018: Journal of Biomaterials Applications
Kazuhisa Matsui, Takashi Tachibana, Katsuya Nobuhara, Yasushi Uchiyama
BACKGROUND: The glenohumeral joint is subjected to opposing forces when the direction of shoulder motion is changed, accelerating and decelerating to make the movements. The influence of motion velocity or acceleration on translation of the humeral head has not been evaluated although direction and distance of humeral head translation has been analyzed in real time in normal shoulders. We hypothesized that, in a normal shoulder, the humeral head does not deviate significantly or suddenly during active shoulder rotation regardless of motion velocity...
March 15, 2018: Journal of Experimental Orthopaedics
Katherine L Wright, Yun Jiang, Dan Ma, Douglas C Noll, Mark A Griswold, Vikas Gulani, Luis Hernandez-Garcia
In this study, the acquisition of ASL data and quantification of multiple hemodynamic parameters was explored using a Magnetic Resonance Fingerprinting (MRF) approach. A pseudo-continuous ASL labeling scheme was used with pseudo-randomized timings to acquire the MRF ASL data in a 2.5 min acquisition. A large dictionary of MRF ASL signals was generated by combining a wide range of physical and hemodynamic properties with the pseudo-random MRF ASL sequence and a two-compartment model. The acquired signals were matched to the dictionary to provide simultaneous quantification of cerebral blood flow, tissue time-to-peak, cerebral blood volume, arterial time-to-peak, B1 , and T1...
March 12, 2018: Magnetic Resonance Imaging
Mario Fleischer, Alexander Mainka, Steffen Kürbis, Peter Birkholz
Recently, 3D printing has been increasingly used to create physical models of the vocal tract with geometries obtained from magnetic resonance imaging. These printed models allow measuring the vocal tract transfer function, which is not reliably possible in vivo for the vocal tract of living humans. The transfer functions enable the detailed examination of the acoustic effects of specific articulatory strategies in speaking and singing, and the validation of acoustic plane-wave models for realistic vocal tract geometries in articulatory speech synthesis...
2018: PloS One
Futoshi Matsushita, Hirotaka Kida, Ken-Ichi Tabei, Chizuru Nakano, Keita Matsuura, Yuichiro Ii, Ryogen Sasaki, Akira Taniguchi, Yugo Narita, Masayuki Maeda, Masayuki Satoh, Hidekazu Tomimoto
Introduction: This study aims to investigate the association between the presence and frequency of cortical lesions (CLs), and the clinical and psychological features of multiple sclerosis (MS). Methods: A total of 19 patients with MS were examined using double inversion recovery (DIR) sequences with 3T magnetic resonance imaging (MRI) and classified into two groups: CL and non-CL. In-house software was used to quantitatively determine the atrophy of each brain region...
March 2018: Brain and Behavior
Shin-Ichi Oikawa, Kiyoto Shiga, Daisuke Saito, Katsunori Katagiri, Aya Ikeda, Kodai Tuchida, Jun Miyaguchi, Kazuyuki Ishida, Tamotsu Sugai
The present study aimed to investigate the usefulness of contrast-enhanced ultrasonography (CEUS) and a newly developed analysis software for the detection of microcapillary network distribution in lymph nodes of patients with head and neck cancer (HNC) by comparing the CEUS and histopathological findings. Patients that were diagnosed with HNC between February and September 2016 were enrolled. A total of five patients underwent resection of the primary tumor and neck dissection as their initial treatment. The cervical lymph nodes of these patients were analyzed by CEUS intraoperatively, and their surgical specimens were examined histopathologically...
April 2018: Oncology Letters
Yan Liang, Yang-Kun Chen, Vincent Chung-Tong Mok, De-Feng Wang, Gabor S Ungvari, Winnie Chiu-Wing Chu, Hee-Ju Kang, Wai-Kwong Tang
Objective: All types of cerebral small vessel disease (SVD) markers including lacune, white matter hyperintensities (WMH), cerebral microbleeds, and perivascular spaces were found to be associated with poststroke depressive symptoms (PDS). This study explored whether the combination of the four markers constituting an overall SVD burden was associated with PDS. Methods: A cohort of 563 patients with acute ischemic stroke were followed over a 15-month period after the index stroke. A score of ≥7 on the 15-item Geriatric Depression Scale was defined as clinically significant PDS...
2018: Frontiers in Aging Neuroscience
Trisha L Roy, Thomas L Forbes, Andrew D Dueck, Graham A Wright
Magnetic resonance imaging (MRI) has advanced significantly in the past decade and provides a safe and non-invasive method of evaluating peripheral artery disease (PAD), with and without using exogenous contrast agents. MRI offers a promising alternative for imaging patients but the complexity of MRI can make it less accessible for physicians to understand or use. This article provides a brief introduction to the technical principles of MRI for physicians who manage PAD patients. We discuss the basic principles of how MRI works and tailor the discussion to how MRI can evaluate anatomic characteristics of peripheral arterial lesions...
March 1, 2018: Vascular Medicine
Idil Kurut Aysin, Ayhan Askin, Berna Dirim Mete, Ece Guvendi, Murat Aysin, Hikmet Kocyigit
Objective: The study aimed to investigate whether there is any association of anterior knee pain and knee function with chondromalacia stage and patellofemoral alignment in patients with anterior knee pain for over a month and with chondromalacia patellae (CMP) detected by magnetic resonance imaging (MRI). Materials and Methods: We reviewed the medical records of 38 patients who underwent a knee MRI examination and were diagnosed with chondromalacia based on the MRI...
February 2018: Eurasian Journal of Medicine
Malo Le Hanneur, Andres A Maldonado, Benjamin M Howe, Michelle L Mauermann, Robert J Spinner
BACKGROUND: Several hypotheses have been proposed for the pathophysiology of suprascapular nerve (SSN) palsy, including compression, traction, and nerve inflammation. OBJECTIVE: To provide insight into the pathophysiology of isolated nontraumatic SSN palsy by performing critical reinterpretations of electrodiagnostic (EDX) studies and magnetic resonance (MR) images of patients with such diagnosis. METHODS: We retrospectively reviewed all patients referred to our institution for the past 20 yr with a diagnosis of nontraumatic isolated suprascapular neuropathy who had an upper extremity EDX study and a shoulder or brachial plexus MR scan...
February 26, 2018: Neurosurgery
Veysel Antar, Okan Turk
OBJECTIVE: Craniovertebral junctional anomalies constitute a technical challenge. Surgical opening of atlantoaxial joint region is a complex procedure especially in patients with nuchal deformity like basilar invagination. This region has actually very complicated anatomical and functional characteristics, including multiple joints providing extension, flexion, and wide rotation. In fact, it is also a bottleneck region where bones, neural structures, and blood vessels are located. Stabilization surgery regarding this region should consider the fact that the area exposes excessive and life-long stress due to complex movements and human posture...
March 2018: Journal of Korean Neurosurgical Society
R Michael Meneghini
The investigation of recurrent instability after total hip arthroplasty requires a thorough history and physical examination focused on characterizing the dislocation events and the patient factors that contribute to instability. Radiographic studies include plain radiographs, in particular a cross-table lateral, and computed tomography to accurately assess the implant orientation relative to the patient's native anatomy. More advanced imaging such as magnetic resonance imaging may be useful to assess abductor tendon integrity...
March 6, 2018: Journal of Arthroplasty
Asad A Khawaja, Dmitry Tumin, Ralph J Beltran, Joseph D Tobias, Joshua C Uffman
OBJECTIVES: General anesthesia or sedation can facilitate the completion of diagnostic radiological studies in children. We evaluated the incidence, predictors, and causes of adverse events (AEs) when general anesthesia is provided for diagnostic radiological imaging. METHODS: Deidentified data from 24 pediatric tertiary care hospitals participating in the Wake-Up Safe registry during 2010-2015 were obtained for analysis. Children 18 years or younger receiving general anesthesia for radiological procedures were identified using Current Procedural Terminology codes, and reported AEs were analyzed if they were associated with anesthetic care at magnetic resonance imaging or computed tomography locations...
March 8, 2018: Journal of Patient Safety
Mark Gainey, Montserrat Carles, Michael Mix, Philipp T Meyer, Michael Bock, Anca-Ligia Grosu, Dimos Baltas
Recently, there has been an increase in the imaging modalities available for radiotherapy planning and radiotherapy prognostic outcome: dual energy computed tomography (CT; DECT), dynamic contrast enhanced CT, dynamic contrast enhanced magnetic resonance imaging (MRI), diffusion-weighted MRI, positron emission tomography-CT, dynamic contrast enhanced ultrasound, magnetic resonance spectroscopy and positron emission tomography-MR. These techniques enable more precise gross tumor volume definition than CT alone and moreover allow subvolumes within the gross tumor volume to be defined which may be given a boost dose or an individual voxelized dose prescription may be derived...
March 9, 2018: Future Oncology
Marzena Barczuk-Falęcka, Łukasz A Małek, Hubert Krysztofiak, Danuta Roik, Michał Brzewski
Physical training is associated with changes in cardiac morphology called the "athlete's heart", which has not been sufficiently studied in children. The aim of the study was to analyze cardiac adaptation to exercise in pre-adolescent soccer players. Thirty-six soccer players (mean age 10.1 ± 1.4 years) and 24 non-athlete male controls (10.4 ± 1.7 years) underwent cardiac magnetic resonance. Measurements of myocardial mass, end-diastolic and end-systolic volume, stroke volume and ejection fraction for left and right ventricle (LV, RV) were performed...
March 8, 2018: Pediatric Cardiology
Changqie Pan, Yuqing Liu, Minyu Zhou, Wensheng Wang, Min Shi, Malcolm Xing, Wangjun Liao
A multifunctional theranostic nanoplatform integrated with environmental responses has been developed rapidly over the past few years as a novel treatment strategy for several solid tumors. We synthesized pH-sensitive poly(β-thiopropionate) nanoparticles with a supermagnetic core and folic acid (FA) conjugation (FA-doxorubicin-iron oxide nanoparticles [FA-DOX@ IONPs]) to deliver an antineoplastic drug, DOX, for the treatment of folate receptor (FR)-overexpressed breast cancer. In addition to an imaging function, the nanoparticles can release their payloads in response to an environment of pH 5, such as the acidic environment found in tumors...
2018: International Journal of Nanomedicine
J Zhang, M Liu, L Zhou, Z B Zhang, J M Wang, Y W Jiang, Y Wu
Objective: To analyze the clinical and imaging features of hypomyelination with brain stem and spinal cord involvement and leg spasticity (HBSL) due to mutations in DARS, and to identify DARS mutations responsible for HBSL. Methods: Data on 2 HBSL patients who were admitted to the pediatric department of Peking University First Hospital from January 2009 through December 2016 were reviewed and the 2 patients were followed up. Targeted next generation sequencing, whole exome sequencing and Sanger sequencing were employed to identify potential genetic variations of the children and their parents...
March 2, 2018: Zhonghua Er Ke za Zhi. Chinese Journal of Pediatrics
Dominik A Moser, Gaelle E Doucet, Won Hee Lee, Alexander Rasgon, Hannah Krinsky, Evan Leibu, Alex Ing, Gunter Schumann, Natalie Rasgon, Sophia Frangou
Importance: Alterations in multiple neuroimaging phenotypes have been reported in psychotic disorders. However, neuroimaging measures can be influenced by factors that are not directly related to psychosis and may confound the interpretation of case-control differences. Therefore, a detailed characterization of the contribution of these factors to neuroimaging phenotypes in psychosis is warranted. Objective: To quantify the association between neuroimaging measures and behavioral, health, and demographic variables in psychosis using an integrated multivariate approach...
March 7, 2018: JAMA Psychiatry
S Ibrahimi, A A Mroué, E Francois, R Jagodzinski
A 34-year-old woman in the 22nd week of gestation presented with generalized pruritis and weight loss since the first trimester of pregnancy. Physical examination revealed cutaneous scratch lesions, jaundice, and hepatomegaly. Blood tests revealed cholestasis with elevated direct bilirubinemia. Auto-antibody and viral hepatitis tests were negative. Liver ultrasound was normal. The initial diagnosis was cholestasis of pregnancy. However despite treatment with ursodeoxycholic acid, the patient did not improve...
July 2017: Acta Gastro-enterologica Belgica
Andrew T Pennock, Jerry Dwek, Emily Levy, Philip Stearns, John Manning, M Morgan Dennis, Amanda Davis-Juarez, Tracey Bastrom, Kenneth S Taylor
Background: Youth baseball is extremely popular in the United States, but it has been associated with shoulder pain and injury. The incidence of shoulder abnormalities in this athletic population has yet to be defined. Purpose: To examine abnormalities noted on magnetic resonance imaging (MRI) in the shoulders of asymptomatic Little League baseball players and to correlate these findings with the players' throwing history and physical examinations. Study Design: Case-control study; Level of evidence, 3...
February 2018: Orthopaedic Journal of Sports Medicine
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