scholarly journals Synthetic MRI for Stroke: A Qualitative and Quantitative Pilot Study

2022 ◽  
Author(s):  
Joachim André ◽  
Sami Barrit ◽  
Patrice Jissendi Tchofo
Keyword(s):  
Pilot Study ◽  
Image Quality ◽  
Brain Regions ◽  
Normal Brain ◽  
P Values ◽  
Tissue Properties ◽  
Qualitative And Quantitative ◽  
Stroke Imaging ◽  
Suspected Stroke ◽  
Synthetic Mri

Abstract PurposeSynthetic MR provides quantitative multiparametric data about tissue properties in a fast single-acquisition. We compared synthetic and conventional image quality and investigated synthetic relaxometry of acute and chronic ischemic lesions to support its interest in stroke imaging. MethodsFor this pilot study, we prospectively acquired synthetic and conventional brain MR of 43 consecutive adult patients with suspected stroke. We studied a total of 136 lesions, of which 46 DWI-positive with restricted ADC (DWI+/rADC), 90 white matter T2/FLAIR hyperintensities (WMH), and 430 normal brain regions (NBR). We assessed image quality for lesion definition according to a 3-level score by two readers of different experiences. We compared relaxometry of lesions and regions of interest.Results Synthetic images were superior to their paired conventional images for lesion definition except for sFLAIR (sT1 or sPSIR vs. cT1 and sT2 vs. cT2 for DWI+/rADC and WMH definition; p-values <.001) with substantial to almost perfect inter-rater reliability (κ ranging from 0.711 to 0.932, p-values <.001). We found significant differences in relaxometry between lesions and NBR and between acute and chronic lesions (T1, T2, and PD of DWI+/rADC or WMH vs. mirror NBR; p-values <.001; T1 and PD of DWI+/rADC vs. WMH; p-values of 0.034 and 0.008).Conclusion Synthetic MR may contribute to stroke imaging by fast acquiring consistent relaxometry data and accessible derived images of interest for the study of ischemic lesions.

Perivascular (Virchow–Robin) spaces

2021 ◽  
pp. 86-89
Keyword(s):  
Blood Vessels ◽  
Shape Change ◽  
Lymphatic Drainage ◽  
Brain Regions ◽  
Mechanical Trauma ◽  
Normal Brain ◽  
Perivascular Spaces ◽  
Mr Images ◽  
Lenticulostriate Artery ◽  
The Brain

Perivascular spaces; also known as the Virchow-Robin Spaces, they are pleurally lined, interstitial fluid-filled areas that surround certain blood vessels in various organs, especially the perforating arteries in the brain, with an immunological function. Dilated perivascular spaces are divided into three types. The first of these is on the lenticulostriate artery, the second is in the cortex following the path of the medullary artery, and the third is in the midbrain. Perivascular spaces can be detected as areas of dilatation on MR images. Although a limited number of perivascular spaces can be seen in a normal brain, the increase in the number of these spaces has been associated with the incidence of various neurodegenerative diseases. Different theories have been suggested about the tendency of the perivascular spaces to expand. Current theories include mechanical trauma due to cerebrospinal fluid pulsing, elongation of penetrating blood vessels, unusual vascular permeability, and increased fluid exudation. In addition, the brain tissue atrophy that occurs with aging; It is thought to contribute to the widening of perivascular spaces by causing shrinkage of arteries, altered arterial wall permeability, obstruction of lymphatic drainage pathways and vascular demyelination. It is assumed that the clinical significance of the dilation tendencies of the perivascular spaces is based on shape change rather than size. These spaces have been mostly observed in brain regions such as corpus callosum, cingulate gyrus, dentate nucleus, substantia nigra and various arterial basins including lenticulostriate artery and mesencephalothalamic artery. In conclusion, when sections are taken on MR imaging, it is possible that perivascular spaces may be confused with microvascular diseases and some neurodegenerative changes. In addition, perivascular spaces can be seen without pathological significance. Therefore, it would be appropriate to investigate the etiological relationship by evaluating the radiological findings and clinical picture together.

A New Method for Continuous Recording of Trunk Postures while Playing Golf

1996 ◽  
Vol 12 (1) ◽  
pp. 116-129 ◽  
Author(s):  
José C. Derksen ◽  
Marcel P. van Riel ◽  
Chris J. Snijders
Keyword(s):  
Pilot Study ◽  
Quantitative Data ◽  
Biomechanical Study ◽  
New Method ◽  
Continuous Recording ◽  
Trunk Movement ◽  
Qualitative And Quantitative ◽  
Long Period ◽  
Trunk Movements ◽  
Spinal Load

In this paper a new method for the registration of trunk movements is presented. With this method, called the Portable Posture Registration Set (PPRS), movements can be recorded continuously over a long period of time. The purpose of this study was to test whether the PPRS can be applied in golf. A pilot study using 4 male golfers demonstrated that qualitative and quantitative data on trunk movements in golf can be collected with the PPRS. The inclination of the trunk proved to be large (40–45°) in all swings tested, resulting in a considerable load on the back. The contribution of torsion to the spinal load was relatively small, especially in the putt, which showed very little movement in the transverse and frontal planes. However, putting accounted for most of the total spinal load in playing a course. Even when playing a round of 18 holes, subjects did not experience any hindrance or discomfort from the sensors or the recorder. This method seems to offer new possibilities in the biomechanical study of trunk movement in golf.

scholarly journals UCAN: A Learning-based Model to Enhance Poorly Exposed Images

2020 ◽  
Author(s):  
Lucas R. V. Messias ◽  
Cristiano R. Steffens ◽  
Paulo L. J. Drews-Jr ◽  
Silvia S. C. Botelho
Keyword(s):  
Image Quality ◽  
Image Enhancement ◽  
Dynamic Range ◽  
Low Contrast ◽  
Qualitative And Quantitative ◽  
Fast Learning ◽  
Proposed Model ◽  
Quantitative Results ◽  
Critical Process ◽  
Poor Lighting

Image enhancement is a critical process in imagebased systems. In these systems, image quality is a crucial factor to achieve a good performance. Scenes with a dynamic range above the capability of the camera or poor lighting are challenging conditions, which usually result in low contrast images, and, with that, we can have the underexposure and/or overexposure problem. In this work, our aim is to restore illexposed images. For this purpose, we present UCAN, a small and fast learning-based model capable to restore and enhance poorly exposed images. The obtained results are evaluated using image quality indicators which show that the proposed network is able to improve images damaged by real and simulated exposure. Qualitative and quantitative results show that the proposed model outperforms the existing models for this objective.

Synthetic MRI of the lumbar spine at 3.0 T: feasibility and image quality comparison with conventional MRI

2019 ◽  
Vol 61 (4) ◽  
pp. 461-470
Author(s):  
Weilan Zhang ◽  
Jingyi Zhu ◽  
Xiaohan Xu ◽  
Guoguang Fan
Keyword(s):  
Lumbar Spine ◽  
Image Quality ◽  
Acquisition Time ◽  
Conventional Mri ◽  
Spinal Lesions ◽  
Spine Imaging ◽  
3.0 T ◽  
Magnetic Resonance Imaging Mri ◽  
Quality Assessments ◽  
Synthetic Mri

Background Synthetic magnetic resonance imaging (MRI), which can generate multiple morphologic MR images as well as quantitative maps from a single sequence, is not widely used in the spine at 3.0 T. Purpose To investigate the feasibility of synthetic MRI of the lumbar spine in clinical practice at 3.0 T. Material and Methods Eighty-four patients with lumbar diseases underwent conventional T1-weighted images, T2-weighted images, short-tau inversion recovery (STIR) images, and synthetic MRI of the lumbar spine at 3.0 T. The quantitative and qualitative image quality and agreement for detection of spinal lesions between conventional and synthetic MRI were compared by two radiologists. Results The signal-to-noise ratios of synthetic MRI showed an inferior image quality in the vertebrae and disc, whereas were higher for spinal canal and fat on the synthetic T1-weighted, T2-weighted, and STIR images. The contrast-to-noise ratios of the synthetic MRI was superior to conventional sequences, except for the vertebrae–disc contrast-to-noise ratio on T1-weighted imaging ( P =  0.005). Image quality assessments showed that synthetic MRI had greater STIR fat suppression ( P <  0.001) and fluid brightness ( P =  0.014), as well as higher degree of artifacts ( P <  0.001) and worse spatial resolution ( P =  0.002). The inter-method agreements for detection of spinal lesions were substantial to perfect (kappa, 0.614–0.925). Conclusion Synthetic MRI is a feasible method for lumbar spine imaging in a clinical setting at 3.0-T MR. It provides morphologic sequences with acceptable image quality, good agreement with conventional MRI for detection of spinal lesions and quantitative image maps with a slightly shorter acquisition time compared with conventional MRI.

scholarly journals Evaluation of mammographic image quality: pilot study comparing five methods.

1992 ◽  
Vol 159 (2) ◽  
pp. 295-301 ◽  
Author(s):  
C B Caldwell ◽  
E K Fishell ◽  
R A Jong ◽  
W J Weiser ◽  
M J Yaffe
Keyword(s):  
Pilot Study ◽  
Image Quality ◽  
Mammographic Image
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