2023 CiteScore: 0.8
pISSN: 2345-5829
eISSN: 2345-5837
Editor-in-Chief:
Mohammad Reza Ay
Chairman:
Saeid Sarkar
Executive Director:
Hossein Ghadiri
Vol 3 No 1-2 (2016)
Original Article(s)
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Introduction: Aging is an important factor affecting bone quality, culminating in cortical bone thinning, increasing the number and size of the pores. As a consequence of these alterations, the free water molecules mobility augments and their longitudinal relaxation time (T1) increases. An MRI with its sensitivity to capture signal from hydrogen proton would be the best candidate to assess the bone quality during aging. By employing an appropriate pulse sequence with a short TE which is capable of acquiring a signal from hydrogen molecules of cortical bone pores before decaying, valuable information about the bone structure was extracted.
Materials and Methods: Five healthy volunteers (3f/2m) were undergone a short TE MR imaging with dual-TR technique at 3T in order to calculate the cortical bone free water T1 . For T1 calculation, the mean signal intensity of the whole cortical bone in long-TR image was divided by the short-TR image to acquire an ‘r’ ratio. This ratio value was used in an equation (described further) to calculate T1 value. The process of cortical bone segmentation was performed manually due to the intense care that it needed for the discrimination of soft tissue from the bone tissue.
Results: The longitudinal relaxation time of human cortical bone free water was quantified using two Gradient Echo STE-MR images differing in TR values and the average of the obtained T1 values was reported to be 589.32 ± 231.52 ms which was in a good agreement with previously reported values in the literature.
Conclusion: The result suggests a successful application of STE-MRI for an accurate quantification of cortical bone T1
-values, with the advantage of widespread clinical availability and a cost-effective procedure. -
Purpose: In brain MRI analysis, image segmentation is commonly used for measuring and visualizing the brain’s anatomical structures, for analyzing brain changes, delineating pathological regions, and image-guided interventions. Since manual segmentation is time-consuming and prone to variable sort of errors, which makes automatic techniques more demanding.
Method: This paper describes a framework for automatic segmentation of both normal and abnormal anatomy from medical images based on adaptive neuro-fuzzy inference system (ANFIS) which is applicable to different types of tumors. The segmentation framework is comprised of five stages: first, Median filter is applied to remove or reduce the noise of images; second, it is followed by EM clustering to segment it into different parts with variousintensities, to be used for feature extraction in the next step. At the fourth stage, extracted features besides ground truth are used as ANFIS training dataset. Fifth and the last, fordetected abnormal sections either edema or tumor core, level set is adopted for a precise detection of abnormal tissues.
Results: This method was applied for 15 High-Grade (HG) and 15 Low-Grade (LG) simulated brain tumor images. Proposed model provided satisfactory outcomes which for the segmentation of whole tumor including both edema and tumor core, Dice index recorded 0.936±0.04 and 0.921±0.02 for HG and LG dataset respectively; however, those of tumor core were 0.899±0/04 and 0.902±0.05 in the mentioned groups.
Conclusion: The results of this study prove fuzzy inference systems and neural networks potential applications in clinical image analysis and tumor evaluation for brain cancers. -
Purpose: In this investigation, after designing an experimental setup, the magnetization parameter of a rectangular bar-shaped permanent magnet has been determined by a Magnetic Field Magnitude and Intensity Meter device.
Methods: In order to achieve this purpose, after finding the geometrical center of mass of the magnet, by moving Hall-Effect sensor in 5mm steps, the magnetic flux intensity has been measured by our recently patented device.
Results: The accuracy of the experimental values in comparison with the available
commercial grade and analytical equations demonstrated have been confirmed. Our device’s results accuracy has also been approved by benchmarking all results. Following that, the magnetization parameter has been extracted using the numerical technique.
Conclusion: Results showed very precise benchmarking and proved the use of this device in measuring the magnetic field in MRI devices. This study will be directed to simulate several subjects like calculating the induced electromotive force -
Purpose: Attention Deficit Hyperactivity Disorder (ADHD) is the current description of the most prevalent psychiatric disorder of childhood. The essential feature is the developmentally inappropriate degree of inattention, impulsiveness and hyperactivity. Manifestations of ADHD usually appear in most situations, including home, school, work, sporting and social settings.
Method: Since the essential feature of ADHD is inattention manner also nonlinear features of EEG may be equivalent to the attention we investigate nonlinear features of the EEG. We evaluated 29 children with AD/HD who were diagnosed by DSM-IV criteria and 20 age-sex matched controls. During recording EEG we showed images to children and asked them to concentrate on those images and number them. Using this method we stimulated visual attention of children.
Result: In this study, we use an MLP neural network as a classifier. By investigating these nonlinear features, we obtained a classification with 96.7% accuracy, using frontal lobe electrodes as the best result.
Conclusion: Results showed a significant difference between the accuracy of the frontal region, and other regions. This result can confirm the defect in the anterior segment of the brain of ADHD children. -
Purpose: Diffusion-Weighted Magnetic Resonance Imaging (DW-MRI) has been used extensively for the early detection of cerebral ischemia. Tissue-equivalent diffusivity phantoms can play a pivotal role in optimizing the existing imaging protocols used for DW-MRI or when examining the usefulness of novel pulse sequences for DW-MRI.The objective of this work was to build a spherical diffusion phantom which mimics the condition typically found in biological tissues.
Methods: To assess the quality control, we prepared Nickel-doped agarose/sucrose gels and to perform a quality control on MRI protocols, we designed a spherical phantom. The quality control protocol was applied on a 3 T clinical MRI system (Siemens) and T1, T2, and ADC maps were generated then calculated the average T1, T2, and ADC values.
Result: ADC measurement with Nickel-doped agarose/sucrose using an EPI DW-MRI protocol was very good. The T1, T2 and ADC measurement shows the relaxation and diffusion properties of this phantom is similar to the ones found in biological tissues especially in biological tissues such as fat tissue and air tissue boundaries.
Conclusion: Nickel-doped agarose/sucrose gels can be used as reference materials for MRI diffusion measurement. A phantom made of these material can be invaluable in optimizing DW-MRI.
