Application Of Magnetic Resonance Imaging Research Articles

Reporter Genes for Brain Imaging Using MRI, SPECT and PET.

The use of molecular imaging technologies for brain imaging can not only play an important supporting role in disease diagnosis and treatment but can also be used to deeply study brain functions. Recently, with the support of reporter gene technology, optical imaging has achieved a breakthrough in brain function studies at the molecular level. Reporter gene technology based on traditional clinical imaging modalities is also expanding. By benefiting from the deeper imaging depths and wider imaging ranges now possible, these methods have led to breakthroughs in preclinical and clinical research. This article focuses on the applications of magnetic resonance imaging (MRI), single-photon emission computed tomography (SPECT), and positron emission tomography (PET) reporter gene technologies for use in brain imaging. The tracking of cell therapies and gene therapies is the most successful and widely used application of these techniques. Meanwhile, breakthroughs have been achieved in the research and development of reporter genes and their imaging probe pairs with respect to brain function research. This paper introduces the imaging principles and classifications of the reporter gene technologies of these imaging modalities, lists the relevant brain imaging applications, reviews their characteristics, and discusses the opportunities and challenges faced by clinical imaging modalities based on reporter gene technology. The conclusion is provided in the last section.

Special Issue on Clinical Applications of Magnetic Resonance Imaging in Genitourinary Cancers

In the field of oncologic imaging, MRI represents one of the most powerful diagnostic tools at physicians’ disposal, with its superb contrast resolution and its capability to assess both the morphological and functional features of neoplasms [...]

Is the Impact Breast Implants with RFID Have on MRI Quality Investigated Thoroughly Enough?

Is the Impact Breast Implants with RFID Have on MRI Quality Investigated Thoroughly Enough?

The use of MRI in urothelial carcinoma.

To conduct a nonsystematic review of the existing literature to investigate the role of Magnetic Resonance Imaging (MRI) in urothelial carcinomas (UCs). Imaging is becoming progressively more crucial in local and distant staging of UCs, especially in cases of bladder cancer (BCa). The primary objective of imaging in patients with BCa is to detect lesions and distinguish T1 from T2 stages, since the treatment varies significantly. The applicability of MRI in the management of UCs has been investigated, particularly focusing on the new evidence on multiparametric MRI (mpMRI) of the bladder and Vesical Imaging-Reporting And Data System score for the description of BCa and discussing the possible utility of MRI for upper tract urothelial carcinomas . Imaging modalities, in particular CT and MRI, are essential tools for the local and distant staging of UCs. MpMRI of the bladder and VI-RADS score accurately define the risk of muscle invasiveness, promoting tailored therapeutic planning. Moreover, mpMRI has also been included in patients' follow-up and in the assessment of response to systematic therapy. MRI utility and possible application in upper tract urothelial carcinomas cases are yet to be discovered.

Is prostate biopsy necessary before radical prostatectomy? New concept and clinical practice

The current diagnosis and treatment concept of prostate cancer is that if prostate cancer is suspected through one or more examination methods, prostate biopsy should be performed to confirm the diagnosis of prostate cancer and then subsequent treatment should be given. Nowadays, the application of multi-parameter magnetic resonance imaging (mpMRI) and prostate-specific membrane antigen (PSMA) PET/CT has further improved the imaging diagnosis of prostate cancer, and the diagnostic accuracy of clinically significant prostate cancer has reached almost 100%. In addition, minimally invasive techniques represented by robot-assisted laparoscopic surgery have developed rapidly, and the safety and postoperative recovery of radical prostatectomy have been significantly improved. Therefore, we proposed the concept of radical prostatectomy avoiding biopsy (RPAB), that is, the patients with high suspicion of prostate cancer by multi-parameter MRI and PSMA PET/CT can be directly treated by radical surgery. Preliminary clinical practice confirmed that this concept is feasible. However, RPAB is not suitable for all prostate cancer patients, and any new concept needs to be supported by long-term and high-quality clinical studies. We predict that RPAB will become a new clinical option and produce good economic and social benefits.

Research Progress on MRI for White Matter Hyperintensity of Presumed Vascular Origin and Cognitive Impairment.

White matter hyperintensity of presumed vascular origin (WMH) is a common medical imaging manifestation in the brains of middle-aged and elderly individuals. WMH can lead to cognitive decline and an increased risk of cognitive impairment and dementia. However, the pathogenesis of cognitive impairment in patients with WMH remains unclear. WMH increases the risk of cognitive impairment, the nature and severity of which depend on lesion volume and location and the patient's cognitive reserve. Abnormal changes in microstructure, cerebral blood flow, metabolites, and resting brain function are observed in patients with WMH with cognitive impairment. Magnetic resonance imaging (MRI) is an indispensable tool for detecting WMH, and novel MRI techniques have emerged as the key approaches for exploring WMH and cognitive impairment. This article provides an overview of the association between WMH and cognitive impairment and the application of dynamic contrast-enhanced MRI, structural MRI, diffusion tensor imaging, 3D-arterial spin labeling, intravoxel incoherent motion, magnetic resonance spectroscopy, and resting-state functional MRI for examining WMH and cognitive impairment.

Cardiac Magnetic Resonance Imaging Techniques and Applications for Pericardial Diseases.

Cardiac magnetic resonance imaging plays a central role among multimodality imaging modalities in the assessment, diagnosis, and surveillance of pericardial diseases. Clinicians and imagers should have a foundational understanding of the utilities, advantages, and limitations of cardiac magnetic resonance imaging and how they integrate with other diagnostic tools involved in the evaluation and management of pericardial diseases. This review aims to outline the contemporary magnetic resonance imaging sequences used to evaluate the pericardium, followed by exploring the main clinical applications of magnetic resonance imaging for identifying pericardial inflammation, constriction, and effusion.

Application of Magnetic Resonance Imaging (MRI) as a Safe & Non-Destructive Method for Monitoring of Fruit & Vegetable in Postharvest Period

To investigate and control quality, one must be able to measure quality-related attributes. Quality of produce encompasses sensory attributes, nutritive values, chemical constituents, mechanical properties, functional properties and defects. MRI has great potential for evaluating the quality of fruits and vegetables. The equipment now available is not feasible for routine quality testing. The image and resolution produced by MRI is quite detailed and can detect tiny changes of structures within the body. For some procedures, contrast agents, such as gadolinium, are used to increase the accuracy of the images. MRI additionally quality, can even examine the histology, histochemistry and structural characteristics of samples. He also mentioned that MRI is used as an on-line sensor in postharvest sorting and processing situations. The equipment now available is not feasible for routine quality testing; however, costs and capabilities are rapidly improving. Each sensor method is based on the measurement of a given constituent or property; therefore, its ability to measure overall quality is only as good as the relationship of that constituent or property to quality as defined for a particular purpose. Improved statistical methods for combining the inputs from several measurements into classification algorithms are being developed

Recent Advances in Nanotheranostic Agents for Tumor Microenvironment-Responsive Magnetic Resonance Imaging.

Nanomaterials integrating a variety of excellent properties (such as controllable/suitable size, surface modifier, and multifunctionality) have attracted increasing attention in the biomedical field and have been considered a new generation of magnetic resonance imaging (MRI) contrast agents (CAs). In recent years, stimuli-responsive nanomaterials with specifically responsive ability have been synthesized as MRI CAs, which can significantly improve the diagnostic sensitivity and accuracy depending on their outstanding performance. Furthermore, the inherent tumor microenvironment (TME) of malignant tumor is considered to possess several unique features, such as low extracellular pH, redox condition, hypoxia, and high interstitial pressure, that are significantly different from healthy tissues. Hence, constructing nanomaterials for TME-responsive MRI as an emerging strategy is expected to overcome the current obstacles to precise diagnosis. This review focuses on recent advances of nanomaterials in their application of TME-responsive MRI that trigger the diagnostic function in response to various endogenous stimulations, including pH, redox, enzyme, and hypoxia. Moreover, the future challenges and trends in the development of nanomaterials serving as TME-responsive MRI CAs are discussed.

Altered spontaneous brain activity in major depressive disorder: An activation likelihood estimation meta-analysis

BackgroundWide application of resting-state functional magnetic resonance imaging (fMRI) in psychiatric research has revealed that major depressive disorder (MDD) manifest abnormal neural activities in several brain regions involving key resting state networks. However, inconsistent results have hampered our understanding of the exact neuropathology associated with MDD. Therefore, our aim was to conduct a meta-analysis to identify the consistent vulnerable brain regions of MDD in resting state, and to reveal the potential pathogenesis of MDD. MethodsA systematic review analysis was conducted on studies involving brain resting-state changes in MDD using low-frequency amplitude (ALFF), fractional low-frequency amplitude (fALFF) and regional homogeneity (ReHo) analysis. The meta-analysis was based on the activation likelihood estimation method, using the software of Ginger ALE 2.3. Results25 studies (892 MDD and 799 healthy controls) were included. Based on the meta-analysis results of ReHo, we found robust reduction of resting-state spontaneous brain activity in MDD, including the left cuneus and right middle occipital gyrus (cluster size = 216, 256 mm3, uncorrected P < 0.0001), while no increased spontaneous activation in any of the brain regions. We also found reduced ALFF in the left middle occipital gyrus (cluster size = 224 mm3, uncorrected P < 0.0001), and no increased spontaneous brain activation in any regions. ConclusionOur meta-analysis study using the activation likelihood estimation method demonstrated that MDD showed significant abnormalities in spontaneous neural activity, compared with healthy controls, mainly in areas associated with visual processing, such as the cuneus and the middle occipital gyrus. Dysfunction of these brain regions may be one of the pathogenesis of MDD.

Image resampling and discretization effect on the estimate of myocardial radiomic features from T1 and T2 mapping in hypertrophic cardiomyopathy

Radiomics is emerging as a promising and useful tool in cardiac magnetic resonance (CMR) imaging applications. Accordingly, the purpose of this study was to investigate, for the first time, the effect of image resampling/discretization and filtering on radiomic features estimation from quantitative CMR T1 and T2 mapping. Specifically, T1 and T2 maps of 26 patients with hypertrophic cardiomyopathy (HCM) were used to estimate 98 radiomic features for 7 different resampling voxel sizes (at fixed bin width), 9 different bin widths (at fixed resampling voxel size), and 7 different spatial filters (at fixed resampling voxel size/bin width). While we found a remarkable dependence of myocardial radiomic features from T1 and T2 mapping on image filters, many radiomic features showed a limited sensitivity to resampling voxel size/bin width, in terms of intraclass correlation coefficient (> 0.75) and coefficient of variation (< 30%). The estimate of most textural radiomic features showed a linear significant (p < 0.05) correlation with resampling voxel size/bin width. Overall, radiomic features from T2 maps have proven to be less sensitive to image preprocessing than those from T1 maps, especially when varying bin width. Our results might corroborate the potential of radiomics from T1/T2 mapping in HCM and hopefully in other myocardial diseases.

Application of Magnetic Resonance Imaging in Anal Fistula Operation

Application of Magnetic Resonance Imaging in Anal Fistula Operation

Sintering, microstructure and properties of absorbable Fe–Mn-xCu alloys

One issue with Fe-based biodegradable alloys is their relatively slow degradation rate inside the body. In addition, the ferromagnetic nature of Fe intensely limits its application in magnetic resonance imaging (MRI). In this work, the role of copper addition on powder processing, microstructure, and performance of the Fe–35Mn alloy is described. Fe–35Mn based samples containing 0 to 10 wt% Cu were fabricated by ball milling, uniaxial cold pressing, and sintering. The alloys were characterized for their compressive strength, corrosion behavior, and magnetic properties. Results of XRD analysis showed that copper addition promoted ferrite to austenite phase transformation during sintering. Microstructures of the alloys containing up to 3 wt% Cu were composed of a simple solid solution and large pores. However, when Cu content increased to 6 wt%, a free pure Cu phase appeared in the microstructure, resulting in enhanced densification by forming a liquid phase during sintering. Consequently, the compressive yield strength continuously increased with increasing Cu content and reached the maximum value of 203 MPa in the FeMn–10Cu alloy. The corrosion rate also increased with increasing Cu content up to 6 wt%. An average corrosion rate of 0.27 mm/year was found for the FeMn–6Cu alloy, which was more than five times the rate of the base Fe–Mn alloy. The magnetic susceptibility of the alloys decreased with increasing Cu content, indicating a higher MRI compatibility.

Design of a 6-DoF Parallel Robotic Platform for MRI Applications.

In this work, the design, analysis, and characterization of a parallel robotic motion generation platform with 6-degrees of freedom (DoF) for magnetic resonance imaging (MRI) applications are presented. The motivation for the development of this robot is the need for a robotic platform able to produce accurate 6-DoF motion inside the MRI bore to serve as the ground truth for motion modeling; other applications include manipulation of interventional tools such as biopsy and ablation needles and ultrasound probes for therapy and neuromodulation under MRI guidance. The robot is comprised of six pneumatic cylinder actuators controlled via a robust sliding mode controller. Tracking experiments of the pneumatic actuator indicates that the system is able to achieve an average error of 0.69 ± 0.14 mm and 0.67 ± 0.40 mm for step signal tracking and sinusoidal signal tracking, respectively. To demonstrate the feasibility and potential of using the proposed robot for minimally invasive procedures, a phantom experiment was performed in the benchtop environment, which showed a mean positional error of 1.20 ± 0.43 mm and a mean orientational error of 1.09 ± 0.57°, respectively. Experiments conducted in a 3T whole body human MRI scanner indicate that the robot is MRI compatible and capable of achieving positional error of 1.68 ± 0.31 mm and orientational error of 1.51 ± 0.32° inside the scanner, respectively. This study demonstrates the potential of this device to enable accurate 6-DoF motions in the MRI environment.

Applications of Advanced MRI to Disorders of Consciousness.

Disorder of consciousness (DoC) after severe brain injury presents numerous challenges to clinicians, as the diagnosis, prognosis, and management are often uncertain. Magnetic resonance imaging (MRI) has long been used to evaluate brain structure in patients with DoC. More recently, advances in MRI technology have permitted more detailed investigations of the brain's structural integrity (via diffusion MRI) and function (via functional MRI). A growing literature has begun to show that these advanced forms of MRI may improve our understanding of DoC pathophysiology, facilitate the identification of patient consciousness, and improve the accuracy of clinical prognostication. Here we review the emerging evidence for the application of advanced MRI for patients with DoC.

Application and interpretation of vessel wall magnetic resonance imaging for intracranial atherosclerosis: a narrative review

Background and ObjectiveAtherosclerosis is a systemic disease that occurs in the arteries, and it is the most important causative factor of ischemic stroke. Vessel wall magnetic resonance imaging (VWMRI) is one of the best non-invasive methods for displaying the vascular features of intracranial atherosclerosis. The main clinical applications of this technique include the exploration of the pathogenesis of intracranial atherosclerotic lesions, follow-up monitoring, and treatment prognosis judgment. As the demand for intracranial VWMRI increases in clinical practice, radiologists should be aware of the selection of imaging parameters and how they affect image quality, clinical indications, evaluation methods, and limitations in interpreting these images. Therefore, this review focused on describing how to perform and interpret VWMRI of intracranial atherosclerotic lesions.MethodsWe searched the studies on the application of VWMRI in the PubMed database from January 1, 2000 to March 31, 2022, and focused on the analysis of related studies on VWMRI in atherosclerotic lesions, including technical application, expert consensus, imaging characteristics, and the clinical significance of intracranial atherosclerotic lesions.Key Content and FindingsWe reviewed and summarized recent advances in the clinical application of VWMRI in atherosclerotic diseases. Currently accepted principles and expert consensus recommendations for intracranial VWMRI include high spatial resolution, multiplanar two and three-dimensional imaging, multiple tissue-weighted sequences, and blood and cerebrospinal fluid suppression. Understanding the characteristics of VWMRI of normal intracranial arteries is the basis for interpreting VWMRI of atherosclerotic lesions. Evaluating VWMRI imaging features of intracranial atherosclerotic lesions includes plaque morphological and enhancement characteristics. The evaluation of atherosclerotic plaque stability is the highlight of VWMRI.ConclusionsVWMRI has a wide range of clinical applications and can address important clinical questions and provide critical information for treatment decisions. VWMRI plays a key role in the comprehensive evaluation and prevention of intracranial atherosclerosis. However, intracranial VWMRI is still unable to obtain in vivo plaque pathological specimens for imaging—pathological comparison is the most significant limitation of this technique. Further technical improvements are expected to reduce acquisition time and may ultimately contribute to a better understanding of the underlying pathology of lesions on VWMRI.

Application of Scanning Magnetic Resonance Imaging in the Diagnosis of Prenatal Placental Implantation and Related Care.

In order to solve the problem of scanning magnetic resonance imaging in prenatal diagnosis, the application and research of placental implantation have been proposed. Placental implantation is a serious obstetric emergency, which refers to the abnormal attachment of placental villi caused by the dysplasia of decidual basal layer. A study from the United States showed that the incidence of placental implantation in pregnant women during delivery increased from 9.9/30000 to 11.6/20000 from 2006 to 2019, which increased the risk of prenatal or postpartum hemorrhage, hysterectomy, stillbirth, abdominal organ injury, and so on. Clinically, patients can show severe prenatal or postpartum hemorrhage, postpartum placental retention, uterine perforation, and secondary infection, which may seriously endanger the lives of pregnant mothers and fetuses. Placental implantation can also have no obvious symptoms before delivery, which leads to insufficient prenatal diagnosis. Gielchinsky retrospectively studied 410 patients with placental implantation and found that only 9 patients were detected by prenatal ultrasound or magnetic resonance imaging (MRI), and the detection rate was only 6.6%. It can be seen that if the accurate diagnosis of placental implantation can be made before prenatal or symptoms appear, clinical intervention treatment can be carried out in time to reduce the probability of hysterectomy and improve the examination means of patients' prerecovery. At present, studies at home and abroad suggest that it has good clinical application value and research prospect in the clinical diagnosis of placental implantation.

MRI in liver cirrhosis

AbstractLiver magnetic resonance imaging (MRI) has seen a massive increase in its use over the last decades. Since its first description in the early 1980s, contrast‐enhanced MRI is now the gold standard for the diagnosis of hepatocellular cancer in patients with liver cirrhosis. Techniques like magnetic resonance (MR) elastography and combinations of multiple MR parameters in single scanning protocols are now available and these are opening new possibilities for the assessment of multiple aspects of disease in patients with liver cirrhosis. In this narrative review, we provide an overview of the use of MRI in patients with cirrhosis for the diagnosis of and screening for liver cancer, for the diagnosis of cirrhosis and prediction of long‐term outcomes, and for the evaluation of portal hypertension. With the multitude of techniques now available and the number of cirrhosis aspects that can be assessed by single scans make the study and application of MRI an attractive target in the search for a technique for use in this group of patients that often have to attend for multiple appointments and multiple tests, including invasive investigations.

Magnetic, Mechanical and Thermal Modeling of Superconducting, Whole-body, Actively Shielded, 3 T MRI Magnets Wound Using MgB2 Strands for Liquid Cryogen Free Operation.

we present magnetic, mechanical and thermal modeling results for a 3 Tesla actively shielded whole body MRI (Magnetic Resonance Imaging) magnet consisting of coils with a square cross section of their windings. The magnet design was a segmented coil type optimized to minimize conductor length while hitting the standard field quality and DSV (Diameter of Spherical Volume) specifications as well as a standard, compact size 3 T system. It had an overall magnet length and conductor length which can lead to conduction cooled designs comparable to NbTi helium bath cooled 3 T MRI magnets. The design had a magnetic field homogeneity better than 10 ppm (part-per-million) within a DSV (Diameter of Spherical Volume) of 48 cm and the total magnet winding length of 1.37 m. A new class of MgB2 strand especially designed for MRI applications was considered as a possible candidate for winding such magnets. This work represents the first magnetic, mechanical and thermal design for a whole-body 3 T MgB2 short (1.37 m length) MRI magnet based on the performance parameters of existing MgB2 wire. 3 Tesla MRI magnet can operate at 20 K at 67 % of its critical current.

Assessment of acute traumatic cervical spinal cord injury using conventional magnetic resonance imaging in combination with diffusion tensor imaging-tractography: a retrospective comparative study.

The application of conventional magnetic resonance imaging (MRI) in combination with diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) to diagnose acute traumatic cervical SCI has not been studied. This study explores the role of MRI with DTI-DTT in the diagnosis of acute traumatic cervical spinal cord injury (SCI). Thirty patients with acute traumatic cervical SCI underwent conventional MRI and DTI-DTT. Conventional MRI was used to detect the intramedullary lesion length (IMLL) and intramedullary hemorrhage length (IMHL). DTI was used to detect the spinal cord's fractional anisotropy (FA) and apparent diffusion coefficient value, and DTT detected the imaginary white matter fiber volume and the connection rates of fiber tractography (CRFT). Patients' neurological outcome was determined using the American Spinal Injury Association (ASIA) Impairment Scale (AIS) grades. Patients were divided into group A (without AIS grade conversion) and group B (with AIS grade conversion). The IMLL and IMHL of group A were significantly higher than those of group B. The FA and CRFT of group A were significantly lower than those of group B. The final AIS grade was negatively correlated with the IMLL and IMHL, and positively correlated with the FA and CRFT. According to imaging features based on conventional MRI and DTI-DTT, we propose a novel classification and diagnostic procedure. The combination of conventional MRI with DTI-DTT is a valid diagnostic approach for SCI. Lower IMLL and IMHL, and higher FA value and CRFT are linked to better neurological outcomes.