scholarly journals Noise-residue learning convolutional network model for magnetic resonance image enhancement

2021 ◽  
Vol 2089 (1) ◽  
pp. 012029
Author(s):  
Ram Singh ◽  
Lakhwinder Kaur

Abstract Magnetic Resonance Image (MRI) is an important medical image acquisition technique used to acquire high contrast images of human body anatomical structures and soft tissue organs. MRI system does not use any harmful radioactive ionized material like x-rays and computerized tomography (CT) imaging techniques. High-resolution MRI is desirable in many clinical applications such as tumor segmentation, image registration, edges & boundary detection, and image classification. During MRI acquisition, many practical constraints limit the MRI quality by introducing random Gaussian noise and some other artifacts by the thermal energy of the patient body, random scanner voltage fluctuations, body motion artifacts, electronics circuits impulse noise, etc. High-resolution MRI can be acquired by increasing scan time, but considering patient comfort, it is not preferred in practice. Hence, postacquisition image processing techniques are used to filter noise contents and enhance the MRI quality to make it fit for further image analysis tasks. The main motive of MRI enhancement is to reconstruct a high-quality MRI while improving and retaining its important features. The new deep learning image denoising and artifacts removal methods have shown tremendous potential for high-quality image reconstruction from noise degraded MRI while preserving useful image information. This paper presents a noise-residue learning convolution neural network (CNN) model to denoise and enhance the quality of noise-corrupted low-resolution MR images. The proposed technique shows better performance in comparison with other conventional MRI enhancement methods. The reconstructed image quality is evaluated by the peak-signal-to-noise ratio (PSNR) and structural similarity index (SSIM) metrics by optimizing information loss in reconstructed MRI measured in mean squared error (MSE) metric.

2022 ◽  
Vol 2161 (1) ◽  
pp. 012036
Author(s):  
Ram Singh ◽  
Lakhwinder Kaur

Abstract Restoration of high-quality brain Magnetic Resonance Image (MRI) from the sparse under-sampled complex k-space signal is a widely studied ill-posed inverse transform problem. A deep learning-based data-adaptive and data-driven convolutional technique has been proposed for high-quality MRI recovery from its under-sampled complex domain k-space signal. The uniform subsampling process is very slow in phase-encoding to generate high-resolution images. The longer scan times degrade the perceptual image quality. Various factors contribute to image degradation during data acquisition such as the inception of body motion artifacts, the thermal energy effects of the body, and random noise artifacts due to voltage fluctuations. Keeping in view the patient’s critical condition and comfort, longer scan times are not preferred in practice. To reduce the image acquisition time, noise levels, and motion artifacts in the MR images, Compressive Sensing (CS) provides an accelerated way to reconstructs the high-quality MR image from very limited signal measurements acquired much below the Nyquist rate. However, such data acquisition strategies require advanced computer algorithms for the reconstruction of high-quality MRI from the undersampled MRI data. An improved CNN-based MRI reconstructed algorithm has been presented in this paper which shows better performance to reconstruct high-quality MRI than similar other MR image reconstruction algorithms. The performance of the proposed algorithm is measured by image quality checking tools such as normalized-MSE, PSNR, and SSIM.


Author(s):  
Alan P. Koretsky ◽  
Afonso Costa e Silva ◽  
Yi-Jen Lin

Magnetic resonance imaging (MRI) has become established as an important imaging modality for the clinical management of disease. This is primarily due to the great tissue contrast inherent in magnetic resonance images of normal and diseased organs. Due to the wide availability of high field magnets and the ability to generate large and rapidly switched magnetic field gradients there is growing interest in applying high resolution MRI to obtain microscopic information. This symposium on MRI microscopy highlights new developments that are leading to increased resolution. The application of high resolution MRI to significant problems in developmental biology and cancer biology will illustrate the potential of these techniques.In combination with a growing interest in obtaining high resolution MRI there is also a growing interest in obtaining functional information from MRI. The great success of MRI in clinical applications is due to the inherent contrast obtained from different tissues leading to anatomical information.


IEEE Access ◽  
2021 ◽  
Vol 9 ◽  
pp. 14608-14618
Author(s):  
Ling Tan ◽  
Wenjie Ma ◽  
Jingming Xia ◽  
Sajib Sarker

2021 ◽  
pp. 026835552110451
Author(s):  
Shanshan Shen ◽  
Chunhui Shan ◽  
Yanqin Lan ◽  
Yingmin Chen ◽  
Jikuan Li ◽  
...  

Purpose To explore the feasibility of high-resolution MRI 3-dimensional (3D) CUBE T1-weighted magnetic resonance imaging (MRI) in combination with non-contrast-enhanced (NCE) magnetic resonance venography (MRV) for the assessment of lumen stenosis in May–Thurner syndrome. Methods Twenty-nine patients underwent computed tomography venography (CTV) and high-resolution MRI-CUBE T1, and NCE MRV acquisitions. ANOVA and LSD tests were used to compare the stenosis rate and narrowest and distal diameters of the vessel lumen. Results There were no significant differences in the estimated stenosis rate between CTV, CUBE T1, and NCE MRV (p = 0.768). However, there were significant differences in the measured stenosis diameters of the left common iliac vein (LCIV), with CTV giving the largest mean diameter and CUBE had the smallest mean diameter (p < 0.05). The measured normal LCIV diameters did not significantly differ between MRV and CUBE (p = 0.075) but were significantly larger on CTV than on MRV and CUBE (p < 0.05). Conclusions Compared with CTV, a combination of CUBE and MRV could provide an improved assessment of the degree of lumen stenosis in May–Thurner syndrome and demonstrate acute thrombosis. MRI underestimates the diameter of the vessel in comparison with CTV. MRI can be a substitute tool for Duplex ultrasound and CTV.


2019 ◽  
Vol 61 (4) ◽  
pp. 471-479
Author(s):  
Simon Krabbe ◽  
Mikkel Østergaard ◽  
Inge J Sørensen ◽  
Jakob Møller ◽  
Bente Jensen ◽  
...  

Background Sagittal magnetic resonance (MR) images are typically obtained with the same spatial resolution along the entire spine, but cervical vertebrae are smaller and may be harder to assess. Purpose To investigate if high-resolution (high-res) short tau inversion recovery (STIR) and T1-weighted turbo spin echo (T1W) MR imaging (MRI) sequences are superior to standard resolution for detecting inflammatory and structural lesions in the cervical spine of patients with axial spondyloarthritis. Material and Methods Images were obtained in 36 patients. Voxel sizes at high/standard resolution were 1.99/4.33 mm3 (STIR) and 0.89/3.71 mm3 (T1W). High-resolution and standard-resolution images were scored by two readers according to the Canada-Denmark (CANDEN) MRI spine scoring system. Results Higher bone marrow edema scores were obtained at high resolution versus standard resolution (mean 2.1 vs. 1.2, P = 0.040), whereas fat lesion scores (1.8 vs. 1.5, P = 0.27) and new bone formation scores (3.5 vs. 2.8, P = 0.21) were similar. High-resolution MRI did not classify more patients as positive for bone marrow edema, fat, or new bone formation in the cervical spine compared to standard resolution. Using lateral radiographs as reference standard, sensitivity for detecting anterior corner syndesmophytes with both high-resolution and standard-resolution MRI was low (range 7–22%) and sensitivity for detecting ankylosis was low to moderate (20–55%), while specificity was high (≥96%). Conclusion High-resolution MRI allowed identification of more inflammatory lesions in the cervical spine in patients with axial spondyloarthritis when compared to standard resolution, but it did not classify more patients as positive for bone marrow edema. The slightly increased sensitivity at high-resolution MRI seemed to be too modest to have any real clinical importance.


2005 ◽  
Vol 46 (3) ◽  
pp. 306-309 ◽  
Author(s):  
B. Ludescher ◽  
P. Martirosian ◽  
S. Lenk ◽  
J. Machann ◽  
F. Dammann ◽  
...  

Purpose: To evaluate the feasibility of high‐resolution magnetic resonance imaging (MRI) of trabecular bone of the wrist at 3 Tesla (3T) in vivo and to assess the potential benefit of the increased resolution for clinical assessment of structural changes in spongy bone. Material and Methods: High‐resolution MRI of the wrist was performed with a whole‐body 3T MR scanner using a dedicated circularly polarized transmit–receive wrist‐coil. Two 3D‐FISP sequences with a spatial resolution of 300×300×300 µm3 in a measuring time of TA = 7:51 min, and 200×200×200 µm3 in TA = 9:33 min were applied. Seven young healthy volunteers and three elderly subjects with suspected osteoporosis were examined. The signal‐to‐noise ratio (SNR) in the optimized setup at 3T was compared to measurements at 1.5T. Results: The images at 3T allow microscopic analysis of the bone structure at an isotropic spatial resolution of 200 µm in examination times of <10 min. Differences in the structure of the spongy bone between normal and markedly osteoporotic subjects are well depicted. The SNR at 3T was found up to 16 times higher than at 1.5T applying unchanged imaging parameters. Conclusion: The proposed high‐resolution MRI technique offers high potential in the diagnosis and follow‐up of diseases with impaired bone structure of hand and/or wrist in clinical applications.


1996 ◽  
Vol 175 ◽  
pp. 157-158 ◽  
Author(s):  
J.P. Leahy ◽  
A.H. Bridle ◽  
R.G. Strom

Our Atlas of Extragalactic Radio Sources will present high-quality images of the nearer half of “3CRR”, the sample defined by Laing, Riley & Longair (1983). This is the best-studied complete sample of extragalactic radio sources. All 173 members have secure redshifts and most have been imaged in the radio at high resolution. There is also copious information on their optical line emission, and many have been detected in the sub-mm, FIR, and in X-rays. 3CRR is widely used as a baseline against which fainter, higher-redshift samples can be compared to define the evolution of the population (e.g. Neeser et al. 1995; Law-Green, this conference).


2006 ◽  
Vol 64 (4) ◽  
pp. 916-920 ◽  
Author(s):  
Vera Lúcia Gil-da-Silva-Lopes ◽  
Silvio David Araújo Giffoni

The aim of this study were to describe and to compare structural central nervous system (CNS) anomalies detected by magnetic resonance image (MRI) and computed tomography (CT) in individuals affected by midline facial defects with hypertelorism (MFDH) isolated or associated with multiple congenital anomalies (MCA). The investigation protocol included dysmorphological examination, skull and facial X-rays, brain CT and/or MRI. We studied 24 individuals, 12 of them had an isolated form (Group I) and the others, MCA with unknown etiology (Group II). There was no significative difference between Group I and II and the results are presented in set. In addition to the several CNS anomalies previously described, MRI (n=18) was useful for detection of neuronal migration errors. These data suggested that structural CNS anomalies and MFDH seem to have an intrinsic embryological relationship, which should be taken in account during the clinical follow-up.


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