Selective Non-Excitation of Water or Fat Protons in Magnetic Resonance Imaging

1987 ◽  
Vol 42 (12) ◽  
pp. 1391-1395
Author(s):  
M. Braun ◽  
W. I. Jung ◽  
O. Lutz ◽  
R. Oeschey
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Signal To Noise Ratio ◽  
Fat Distribution ◽  
Whole Body ◽  
Pulse Excitation ◽  
Resonance Imaging ◽  
Spectral Separation ◽  
Magnetic Resonance Imaging Mri ◽  
Test Objects

Nuclear magnetic resonance imaging (MRI) of water and fat protons has been performed with a 1.5 T whole body imager. The highly selective excitation, necessary for the discrimination of the two proton species, has been achieved by different four and five pulse excitation schemes which had to be adapted to the needs of MRI and completed to imaging sequences. Their ability to produce well separated water and fat distribution images of test objects is demonstrated. The special features of the method such as signal-to-noise ratio, insensitivity to rf-field inhomogeneities, ease of implementation and data handling are discussed and compared to existing spectral separation techniques.

RFID-Based Real-Time Navigation for Interventional Magnetic Resonance Imaging: Development and Evaluation of a Novel Tracking System

2017 ◽  
Vol 11 (3) ◽  
Author(s):  
Felix Güttler ◽  
Andreas Heinrich ◽  
Peter Krauß ◽  
Jonathan Guntermann ◽  
Maximilian de Bucourt ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Spatial Resolution ◽  
Radio Frequency Identification ◽  
Signal To Noise Ratio ◽  
Tracking System ◽  
Single Shot ◽  
Resonance Imaging ◽  
Magnetic Resonance Imaging Mri ◽  
Steady State Precession

The purpose of this study was to evaluate the suitability of a novel radio-frequency identification (RFID)-based tracking system for intraoperative magnetic resonance imaging (MRI). A RFID tracking system was modified to fulfill MRI-compatibility and tested according to ASTM and NEMA. The influence of the RFID tracking system on MRI was analyzed in a phantom study using a half-Fourier acquisition single-shot turbospin echo (HASTE) and true fast imaging with steady-state precession sequence (TrueFISP) sequence. The RFID antenna was gradually moved closer to the isocenter of the MR scanner from 90 to 210 cm to investigate the influence of the distance. Furthermore, the RF was gradually changed between 865 and 869 MHz for a distance of 90 cm, 150 cm, and 210 cm to the isocenter of the magnet to investigate the influence of the frequency. The specific spatial resolution was measured with and without a permanent line of sight (LOS). After the modification of the reader, no significant change of the signal-to-noise ratio (SNR) could be observed with increasing distance of the RFID tracking system to the isocenter of the MR scanner. Also, different radio frequencies of the RFID tracking system did not influence the SNR of the MR-images significantly. The specific spatial resolution deviated on average by 8.97 ± 7.33 mm with LOS and 11.23 ± 12.03 mm without LOS from the reference system. The RFID tracking system had no relevant influence on the MR-image quality. RFID tracking solved the LOS problem. However, the spatial accuracy of the RFID tracking system has to be improved for medical usage.

scholarly journals LAB–QA2GO: A free, easy-to-use toolbox for the quality assessment of magnetic resonance imaging data

2019 ◽  
Author(s):  
Christoph Vogelbacher ◽  
Miriam H. A. Bopp ◽  
Verena Schuster ◽  
Peer Herholz ◽  
Andreas Jansen ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Virtual Machine ◽  
Signal To Noise Ratio ◽  
Imaging Data ◽  
Resonance Imaging ◽  
Data Set ◽  
Magnetic Resonance Imaging Mri ◽  
Movement Parameters ◽  
Set Up

AbstractImage characteristics of magnetic resonance imaging (MRI) data (e.g. signal-to-noise ratio, SNR) may change over the course of a study. To monitor these changes a quality assurance (QA) protocol is necessary. QA can be realized both by performing regular phantom measurements and by controlling the human MRI datasets (e.g. noise detection in structural or movement parameters in functional datasets). Several QA tools for the assessment of MRI data quality have been developed. Many of them are freely available. This allows in principle the flexible set-up of a QA protocol specifically adapted to the aims of one’s own study.However, setup and maintenance of these tools bind time, in particular since the installation and operation often require a fair amount of technical knowledge. In this article we present a light-weighted virtual machine, named LAB-QA2GO, which provides scripts for fully automated QA analyses of phantom and human datasets. This virtual machine is ready for analysis by starting it the first time. With minimal configuration in the guided web-interface the first analysis can start within 10 minutes, while adapting to local phantoms and needs is easily possible. The usability and scope of LAB–QA2GO is illustrated using a data set from the QA protocol of our lab. With LAB–QA2GO we hope to provide an easy-to-use toolbox that is able to calculate QA statistics without high effort.

scholarly journals Evaluation of Ethnic Variations in Visceral, Subcutaneous, Intra-Pancreatic, and Intra-Hepatic Fat Depositions by Magnetic Resonance Imaging among New Zealanders

Biomedicines ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 174
Author(s):  
John Zhiyong Yang ◽  
Dech Dokpuang ◽  
Reza Nemati ◽  
Kevin Haokun He ◽  
Andy Baige Zheng ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Adipose Tissue ◽  
New Zealand ◽  
Magnetic Resonance ◽  
Fat Distribution ◽  
Resonance Imaging ◽  
Anthropometric Indices ◽  
Pancreatic Fat ◽  
Hepatic Fat ◽  
Magnetic Resonance Imaging Mri

Anthropometric indices, such as body mass index (BMI), waist circumference (WC), and waist to height ratio (WHtR), have limitations in accurately predicting the pathophysiology of diabetes mellitus, cardiovascular diseases, and metabolic syndrome due to ethnic differences in fat distribution. Recent studies showed that the visceral adipose tissue (VAT) deposition and fat content of internal organs, most notably intra-hepatic and intra-pancreatic fat, has emerged as a more important parameter. In this study, we aimed to assess the coordination between the traditional anthropometric indices and the various fat depositions within different ethnicities in New Zealand. We recruited 104 participants with different ethnic backgrounds, including New Zealand Europeans, Māori (the indigenous people of New Zealand), Pacific Islanders (PI), and Asians. Their weight, height, and WC were measured, and subcutaneous, visceral, intra-hepatic, and intra-pancreatic fat depositions were obtained by magnetic resonance imaging (MRI). The result showed VAT, but not subcutaneous adipose tissue (SAT) depositions at all levels were significantly varied among the three groups. BMI was associated best with L23SAT in NZ Europeans (30%) and L45VAT in Māori/PI (24.3%). WC and WHtR were correlated well with L45SAT in the total population (18.8% and 12.2%, respectively). Intra-pancreatic fat deposition had a positive Pearson relationship with NZ European BMI and Māori/PI WC, but no regression correlation with anthropometric indices. Conventional anthropometric indices did not correspond to the same fat depositions across different ethnic groups.

scholarly journals Value of Multimodal Imaging Approach to Diagnosis of Neurosarcoidosis

2019 ◽  
Vol 9 (10) ◽  
pp. 243 ◽  
Author(s):  
Ilaria Sammarra ◽  
Gaetano Barbagallo ◽  
Angelo Labate ◽  
Baldassare Mondello ◽  
Giuseppe Albonico ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Fdg Pet ◽  
Whole Body ◽  
Resonance Imaging ◽  
1H Mrs ◽  
3T Mri ◽  
18F Fdg ◽  
Neoplastic Disorders ◽  
Magnetic Resonance Imaging Mri

Background: Neurosarcoidosis is a highly variable condition with many clinical and radiological manifestations, that can lead to difficult identification of isolated central nervous system (CNS) forms, because it could mimic inflammatory, infective or neoplastic disorders. Conventional magnetic resonance imaging (MRI) is gold standard to evaluate CNS involvement in neurosarcoidosis, despite the reported high sensitivity but low specificity in the diagnosis. Case presentation: Here, we describe a 52-year-old man that presented to our hospital with a 10-year history of focal seizures, progressive cognitive decline and motor impairment. Neurological examination revealed ataxic gait, bilateral telekinetic and postural tremor, brisk reflexes, left extensor plantar response and hypoesthesia to the right side of body. Brain 3T-magnetic resonance imaging (MRI) showed a leukoencephalopathy with multifocal nodular lesions hyperintense on T2/ fluid attenuated inversion recovery (FLAIR) weighted images involving basal ganglia, periventricular and deep white matter. The interpretation of this pattern on conventional MRI was unclear, opening a challenge on the differential diagnosis between inflammatory, infective or neoplastic disorders. Thus, to better understand the nature of these nodules, single-voxel 1H-magnetic resonance spectroscopy (1H-MRS), contrast enhanced computed tomography (CT) scan and fluorine-18-fluorodeoxyglucose-positron emission tomography (18F-FDG-PET)/3T-MRI were performed. The parenchymal multifocal lesions exhibited slight N-acetyl-aspartate/creatine reduction without abnormal peaks on 1H-MRS, enhancement after the administration of contrast agent on CT and hypermetabolism on 18F-FDG-PET/3T-MRI. All these findings excluded primary neoplasms, metastasis, neurotuberculosis, neurocysticercosis and brain abscess, strongly suggesting a diagnosis of neurosarcoidosis. Therefore, a whole-body 18F-FDG-PET/CT was performed in order to identify subclinical extraneural sarcoidosis localizations, and a hypermetabolic nodule of the left lung upper lobe was found. Subsequently, a biopsy documented the presence of systemic sarcoidosis, supporting a diagnosis of probable neurosarcoidosis. Conclusions: This case demonstrated that a multimodal neuroimaging approach can provide different but complementary evidences to suspect sarcoidosis, especially in apparently CNS isolated forms.

Magnetic Resonance Imaging and Spectroscopy in Schizophrenia

1990 ◽  
Vol 157 (S9) ◽  
pp. 56-65 ◽  
Author(s):  
John L. Waddington ◽  
Eadbhard O'Callaghan ◽  
Conall Larkin ◽  
Oonagh Redmond ◽  
John Stack ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Neuroimaging ◽  
Whole Body ◽  
Resonance Spectroscopy ◽  
Uniform Field ◽  
Resonance Imaging ◽  
New Era ◽  
Imaging And Spectroscopy ◽  
Magnetic Resonance Imaging Mri

In this new era of structural and functional neuroimaging technologies, it is the unsurpassed anatomical resolution of magnetic resonance imaging (MRI) (Andreasen, 1989; and Besson, this supplement) that has resulted in a new generation of studies on cerebral morphology in schizophrenia. With the recent development of whole-body magnets of very high (⩾ 1.5T) and uniform field strength, it has become possible to extend the scope of this approach to include measurement of certain fundamental neurochemical processes, via magnetic resonance spectroscopy (MRS: Hubesch et al, 1989; Lock et al, this supplement). The purpose of this article is to introduce and review critically the existing literature on the application of MRI and MRS to schizophrenia, and to give a preliminary account of some of our own recent studies in these areas.

Development of a Device-to-Image Registration Free Needle Guide for Magnetic Resonance Imaging-Guided Targeted Prostate Biopsy

2020 ◽  
Vol 14 (4) ◽  
Author(s):  
Pankaj Kulkarni ◽  
Sakura Sikander ◽  
Pradipta Biswas ◽  
Sumit Laha ◽  
Heather Cornnell ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Image Registration ◽  
Prostate Biopsy ◽  
Signal To Noise Ratio ◽  
Clinical Environment ◽  
Resonance Imaging ◽  
Transperineal Prostate Biopsy ◽  
Mri Guided ◽  
Magnetic Resonance Imaging Mri

Abstract Significant research has been done in the past decade for the development of magnetic resonance imaging (MRI) guided needle guide (NG) systems for prostate intervention. Most of these systems have been restricted to application in the lab environment with lack of progress toward clinical application. Bulky and complex designs can be attributed to this practice. These systems also demand complex technical setup and usage procedures, which require extra technical personnel during the intervention in addition to specialized training for physicians. Moreover, “device-to-image” registration, essential for accurate and precise targeting, further complicates the overall process while increasing total time for intervention. In order to address these limitations, a simplified, MRI-guided, transperineal prostate biopsy NG system was designed and developed for rapid adoption into the clinical environment. The system consists of a NG device and a software toolkit. It does not require any special intraprocedural technical expertise or dedicated training. Also, to simplify and shorten total procedure time, the device uses the unique concept of “fixed coordinate device” eliminating the need for any device-to-image registration making it clinically friendly. To verify the NG design along with the registration free feature, image quality tests and agar phantom-based targeting experiments were performed under the guidance of 3T MRI scanner. The imaging tests resulted in a distortion of less than 1% in presence of the device and an average change of 1.3% in signal-to-noise ratio. For targeting experiments, maximum in-plane error distance of 3.8 mm with a mean of 2.2 mm and standard deviation of 0.8 mm was observed. The results show that an MRI-compatible simplified intervention device without the need of device-to-image registration is technically feasible.

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