STRUCTURAL MAGNETIC RESONANCE IMAGING (MRI) TECHNIQUES Physiological basis of conventional MRI

Author(s):  
Penta Anil Kumar ◽  
R. Gunasundari ◽  
R. Aarthi

Background: Magnetic Resonance Imaging (MRI) plays an important role in the field of medical diagnostic imaging as it poses non-invasive acquisition and high soft-tissue contrast. However, the huge time is needed for the MRI scanning process that results in motion artifacts, degrades image quality, misinterpretation of data, and may cause uncomfortable to the patient. Thus, the main goal of MRI research is to accelerate data acquisition processing without affecting the quality of the image. Introduction: This paper presents a survey based on distinct conventional MRI reconstruction methodologies. In addition, a novel MRI reconstruction strategy is proposed based on weighted Compressive Sensing (CS), Penalty-aided minimization function, and Meta-heuristic optimization technique. Methods: An illustrative analysis is done concerning adapted methods, datasets used, execution tools, performance measures, and values of evaluation metrics. Moreover, the issues of existing methods and the research gaps considering conventional MRI reconstruction schemes are elaborated to obtain improved contribution for devising significant MRI reconstruction techniques. Results: The proposed method will reduce conventional aliasing artifacts problems, may attain lower Mean Square Error (MSE), higher Peak Signal-to-Noise Ratio (PSNR), and Structural SIMilarity (SSIM) index. Conclusion: The issues of existing methods and the research gaps considering conventional MRI reconstruction schemes are elaborated to devising an improved significant MRI reconstruction technique.


Author(s):  
Mariam Raafat ◽  
Soha H. Talaat ◽  
Salma M. Abdelghaffar ◽  
Engy A. Ali

Abstract Background Endometriosis is a common gynecologic disorder characterized by the implantation of the endometrial tissue ectopically outside the endometrial cavity. It affects about 10% of females at the childbearing period and is estimated to be present up to 20–50% in women complaining of infertility. While laparoscopy is considered the mainstay for diagnosis, magnetic resonance imaging (MRI) is recognized as a useful tool for definitive diagnosis, pre-surgical planning, and determining whether the patient will require multi-specialty involvement. The aim of this study is to evaluate the performance of MRI with the addition of diffusion-weighted imaging (DWI) and T2 star (T2*) to conventional MRI, for the accurate assessment of ectopic endometrium. Results Endometriotic lesions that showed diffusion restriction on DWI were 80.7%, and 96.1% of the endometriotic lesions had signal voids on the T2*W sequence, whereas only 65.4% of the lesions had typical signal intensities on T1WI and T2WI. Diagnostic performance of the MRI examination was improved by the use of the diffusion sequence and better improved by the T2* sequence, compared to the conventional MR protocol sensitivity (SE) = 96.12% and specificity (SP) = 85.7% in T2*-weighted images, SE = 80.7% and SP = 71.4% in DWI, and SE = 65.4% and SP = 71.4% in conventional MRI. P value for conventional MRI was 0.1, which is of no statistical significance (p < 0.05). P value for DWI was 0.016, which is statistically significant (p < 0.05). P value for T2*WI was 0.001, which is more statistically significant (p < 0.05) and could be adequately correlated with laparoscopy. Conclusion DWI and T2* significantly increase MRI diagnostic accuracy by allowing the detection of the hemorrhagic character of the endometriotic lesions. Studies with a large sample size are needed to confirm that they can replace invasive laparoscopy for the diagnosis of endometriosis.


2011 ◽  
Vol 20 (1) ◽  
pp. 33-36 ◽  
Author(s):  
M. Bellani ◽  
M. Baiano ◽  
P. Brambilla

Here, we briefly summarize the most consistent structural magnetic resonance imaging (MRI) studies on amygdala in major depression and debate the effects of clinical variables on amygdalar morphology.


Author(s):  
G.B. Frisoni ◽  
M. Boccardi

Structural magnetic resonance imaging (MRI) provides valid markers of whole brain and regional areas of atrophy in Alzheimer’s disease (AD), which are sensitive to change and correlate with clinical progression. Recent efforts to develop standardized and harmonized protocols for MRI indicate high measurement stability and good reproducibility, supporting the use of these measures in clinical trials. Newer MRI measures of microstructural and connectivity changes are also showing promise as early stage biomarkers of neurodegeneration and potentially as measures of treatment effects. Further work is needed to validate these markers for use in clinical trials.


2020 ◽  
Vol 9 (1) ◽  
pp. RD01-RD04
Author(s):  
Vishakha Mittal ◽  
Rajul Rastogi ◽  
Vijai Pratap ◽  
Satish Pathak ◽  
V.K. Singh ◽  
...  

Background: Diffusion Tensor Imaging (DTI) is a new noninvasive dimension of magnetic resonance imaging (MRI) that provides insight into the white matter microstructure. In epilepsy, widespread DTI abnormalities have been reported in multiple studies in medical literature. In mesial temporal lobe sclerosis (MTLS) patients, conventional MRI may show enlargement of ipsilateral temporal horn & reduction in volume of hippocampus in later stages of disease. However, DTI has been found to be useful in demonstrating the focus of epileptiform activity in brain especially in white matter very early in disease. Since DTI is a sensitive technique to detect subtle structural abnormalities causing epilepsy, hence it can be used to plan more successful epilepsy surgery. Therefore, we conducted a pilot study on twenty patients with seizure disorder using DTI where focal organic brain lesions were ruled-out. Aim: To assess the role of DTI in patients of MLTS with seizures.Subjects and Methods:Twenty patients with seizure disorder secondary to MLTS were evaluated using conventional MRI and DTI. We compared the final diagnosis achieved by clinical parameters correlated with EEG localization.Results:Ten out of twenty patients revealed abnormality on DTI that correlated with EEG correlation without obvious abnormality on conventional MRI representing a significant impact of DTI.Conclusion: DTI can sensitively detect structural changes in MLTS with epilepsy often undetectable on conventional MRI. Hence, DTI can serve as an important radiological tool guiding in management and presurgical evaluation of epilepsy patients considered as idiopathic or and refractory medication.


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