B1 mapping for bias-correction in quantitative T 1 imaging of the brain at 3T using standard pulse sequences

2017 ◽  
Vol 46 (6) ◽  
pp. 1673-1682 ◽  
Author(s):  
Mathieu Boudreau ◽  
Christine L. Tardif ◽  
Nikola Stikov ◽  
John G. Sled ◽  
Wayne Lee ◽  
...  
Keyword(s):  
Bias Correction ◽  
Pulse Sequences ◽  
B1 Mapping ◽  
Standard Pulse ◽  
The Brain

Experimental intracerebral and subarachnoid/intraventricular haemorrhages: MR detectability at 0.5 T and 1.5 T

2002 ◽  
Vol 43 (5) ◽  
pp. 464-473
Author(s):  
M. Alemany Ripoll ◽  
R. Raininko
Keyword(s):  
Cerebrospinal Fluid ◽  
Mr Imaging ◽  
Spin Echo ◽  
Autologous Blood ◽  
Pulse Sequences ◽  
Proton Density ◽  
Gradient Echo ◽  
The Brain ◽  
Formalin Fixed

Purpose: To compare the detectability of small experimental intracranial haemorrhages on MR imaging at 0.5 T and 1.5 T, from hyperacute to subacute stages. Material and Methods: 1 ml of autologous blood was injected into the brain of 15 rabbits to create intraparenchymal haematomas. Since the blood partially escaped into the cerebrospinal fluid (CSF) spaces, detectability of subarachnoid and intraventricular blood was also evaluated. MR imaging at 0.5 T and at 1.5 T was repeated up to 14 days, including T1-, proton density- and T2-weighted (w) spin-echo (SE), FLAIR and T2*-w gradient echo (GE) pulse sequences. The last MR investigation was compared to the formalin-fixed brain sections in 7 animals. Results: The intraparenchymal haematomas were best revealed with T2*-w GE sequences, with 100% of sensitivity at 1.5 T and 90–95% at 0.5 T. Blood in the CSF spaces was significantly ( p < 0.05) better detected at 1.5 T with T2*-w GE sequences and detected best during the first 2 days. The next most sensitive sequence for intracranial blood was FLAIR. SE sequences were rather insensitive. Conclusion: 1.5 T equipment is superior to 0.5 T in the detection of intracranial haemorrhages from acute to subacute stages. T2*-w GE sequences account for this result but other sequences are also needed for a complete examination.

Comparison of T1-weighted spin-echo and 3D T1-weighted multi-shot echo planar pulse sequences in imaging the brain at IT

1999 ◽  
Vol 17 (5) ◽  
pp. 663-668 ◽  
Author(s):  
A.H Karantanas ◽  
N Papanikolaou ◽  
K Vasiou ◽  
E Lavdas
Keyword(s):  
Spin Echo ◽  
Pulse Sequences ◽  
Echo Planar ◽  
The Brain

scholarly journals Magnetic Nanoparticles as In Vivo Tracers for Alzheimer’s Disease

2020 ◽  
Vol 6 (1) ◽  
pp. 13
Author(s):  
Bhargy Sharma ◽  
Konstantin Pervushin
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Early Diagnosis ◽  
Contrast Agents ◽  
Neurological Diseases ◽  
Pulse Sequences ◽  
Experimental Conditions ◽  
Magnetic Resonance Imaging Mri ◽  
The Brain

Drug formulations and suitable methods for their detection play a very crucial role in the development of therapeutics towards degenerative neurological diseases. For diseases such as Alzheimer’s disease, magnetic resonance imaging (MRI) is a non-invasive clinical technique suitable for early diagnosis. In this review, we will discuss the different experimental conditions which can push MRI as the technique of choice and the gold standard for early diagnosis of Alzheimer’s disease. Here, we describe and compare various techniques for administration of nanoparticles targeted to the brain and suitable formulations of nanoparticles for use as magnetically active therapeutic probes in drug delivery targeting the brain. We explore different physiological pathways involved in the transport of such nanoparticles for successful entry in the brain. In our lab, we have used different formulations of iron oxide nanoparticles (IONPs) and protein nanocages as contrast agents in anatomical MRI of an Alzheimer’s disease (AD) brain. We compare these coatings and their benefits to provide the best contrast in addition to biocompatibility properties to be used as sustainable drug-release systems. In the later sections, the contrast enhancement techniques in MRI studies are discussed. Examples of contrast-enhanced imaging using advanced pulse sequences are discussed with the main focus on important studies in the field of neurological diseases. In addition, T1 contrast agents such as gadolinium chelates are compared with the T2 contrast agents mainly made of superparamagnetic inorganic metal nanoparticles.

scholarly journals Quantitative Radiomics: Impact of Pulse Sequence Parameter Selection on MRI-Based Textural Features of the Brain

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
John Ford ◽  
Nesrin Dogan ◽  
Lori Young ◽  
Fei Yang
Keyword(s):  
Pulse Sequence ◽  
Spin Echo ◽  
Pulse Sequences ◽  
Parameter Selection ◽  
Inversion Recovery ◽  
Textural Features ◽  
Imaging Data ◽  
Gradient Echo ◽  
The Impact ◽  
The Brain

Objectives. Radiomic features extracted from diverse MRI modalities have been investigated regarding their predictive and/or prognostic value in a variety of cancers. With the aid of a 3D realistic digital MRI phantom of the brain, the aim of this study was to examine the impact of pulse sequence parameter selection on MRI-based textural parameters of the brain. Methods. MR images of the employed digital phantom were realized with SimuBloch, a simulation package made for fast generation of image sequences based on the Bloch equations. Pulse sequences being investigated consisted of spin echo (SE), gradient echo (GRE), spoiled gradient echo (SP-GRE), inversion recovery spin echo (IR-SE), and inversion recovery gradient echo (IR-GRE). Twenty-nine radiomic textural features related, respectively, to gray-level intensity histograms (GLIH), cooccurrence matrices (GLCOM), zone size matrices (GLZSM), and neighborhood difference matrices (GLNDM) were evaluated for the obtained MR realizations, and differences were identified. Results. It was found that radiomic features vary considerably among images generated by the five different T1-weighted pulse sequences, and the deviations from those measured on the T1 map vary among features, from a few percent to over 100%. Radiomic features extracted from T1-weighted spin-echo images with TR varying from 360 ms to 620 ms and TE = 3.4 ms showed coefficients of variation (CV) up to 45%, while up to 70%, for T2-weighted spin-echo images with TE varying over the range 60–120 ms and TR = 6400 ms. Conclusion. Variability of radiologic textural appearance on MR realizations with respect to the choice of pulse sequence and imaging parameters is feature-dependent and can be substantial. It calls for caution in employing MRI-derived radiomic features especially when pooling imaging data from multiple institutions with intention of correlating with clinical endpoints.

scholarly journals BONE MARROW LESIONS: DIAGNOSIS WITHOUT BIOPSY

2019 ◽  
pp. 19-25
Author(s):  
Yu. V. Nazinkina
Keyword(s):  
Bone Marrow ◽  
Chemical Shift ◽  
Diffusion Weighted Imaging ◽  
Pulse Sequence ◽  
Pulse Sequences ◽  
Bone Marrow Lesions ◽  
Bone Marrow Diseases ◽  
Standard Pulse ◽  
Spinal Mri ◽  
And Diffusion

Routine spinal MRI can be used for bone marrow lesions detection. The most useful standard pulse sequence is T1- WI, which helps both in local and diffuse bone marrow diseases. Additional new pulse sequences, including chemical shift imaging and diffusion weighted imaging, can be used as solving-problem techniques.

MRI of the brain stem using fluid attenuated inversion recivery pulse sequences

1993 ◽  
Vol 35 (5) ◽  
pp. 327-331 ◽  
Author(s):  
B. De Coene ◽  
J. V. Hajnal ◽  
J. M. Pennock ◽  
G. M. Bydder
Keyword(s):  
Brain Stem ◽  
Pulse Sequences ◽  
The Brain

Target Delineation in Radiosurgery for Cerebral Arteriovenous Malformations

1993 ◽  
Vol 34 (5) ◽  
pp. 457-463 ◽  
Author(s):  
W. Y. Guo ◽  
B. Nordell ◽  
B. Karlsson ◽  
M. Söderman ◽  
M. Lindqvist ◽  
...  
Keyword(s):  
Treatment Plan ◽  
Pulse Sequences ◽  
Mr Images ◽  
Target Dose ◽  
Target Delineation ◽  
Large Size ◽  
Appropriate Treatment ◽  
Dose Planning ◽  
Treatment Plans ◽  
The Brain

A study of 6 selected arteriovenous malformation (AVM) patients was performed to investigate the feasibility of delineating an AVM on MR images and to compare the AVM volume outlined on different images. Conventional stereotaxic angiograms, stereotaxic MR images and MR angiograms using several different pulse sequences were obtained prior to radiosurgery. Treatment plans were made from the conventional stereotaxic angiograms. These plans were then transferred to a separate dose planning computer which displayed the MR images with the superimposed isodose lines. The radiated volumes of AVM and brain tissue were measured from these MR images. Last, an assessment was made of the radiation volume needed for an appropriate treatment of the AVM if the treatment plan was made from the MR images rather than from the conventional stereotaxic angiogram. It was possible to delineate medium and large size AVM nidi on stereotaxic MR images based on an integration of information obtained from various pulse sequences. The estimated volumes of the AVM nidi were found to be larger on the conventional stereotaxic angiograms than on the stereotaxic MR images. Consequently, a dose plan based on a conventional stereotaxic angiogram would result in a higher integral dose to the brain with the same target dose. By using reliable MR information it is expected that the volume of brain exposed to radiation could be decreased and the adverse effects of stereotactic radiosurgery for AVM thereby minimized.

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