MRI Technology Research Articles

Low-field MRI: A report on the 2022 ISMRM workshop.

In March 2022, the first ISMRM Workshop on Low-Field MRI was held virtually. The goals of this workshop were to discuss recent low field MRI technology including hardware and software developments, novel methodology, new contrast mechanisms, as well as the clinical translation and dissemination of these systems. The virtual Workshop was attended by 368 registrants from 24 countries, and included 34 invited talks, 100 abstract presentations, 2 panel discussions, and 2 live scanner demonstrations. Here, we report on the scientific content of the Workshop and identify the key themes that emerged. The subject matter of the Workshop reflected the ongoing developments of low-field MRI as an accessible imaging modality that may expand the usage of MRI through cost reduction, portability, and ease of installation. Many talks in this Workshop addressed the use of computational power, efficient acquisitions, and contemporary hardware to overcome the SNR limitations associated with low field strength. Participants discussed the selection of appropriate clinical applications that leverage the unique capabilities of low-field MRI within traditional radiology practices, other point-of-care settings, and the broader community. The notion of "image quality" versus "information content" was also discussed, as images from low-field portable systems that are purpose-built for clinical decision-making may not replicate the current standard of clinical imaging. Speakers also described technical challenges and infrastructure challenges related to portability and widespread dissemination, and speculated about future directions for the field to improve the technology and establish clinical value.

Discovery, characterization, and adipocyte differentiation regulation in perirenal adipose tissue of large yellow croaker (Larimichthys crocea).

Adipose tissue is an essential tissue for lipid deposition in fish and is associated with excess lipid accumulation in aquaculture. However, the knowledge of the distribution and characterization of adipose tissue in fish still needs further investigation. This study for the first time discovered perirenal adipose tissue (PAT) in large yellow croaker by MRI and CT technologies. Then, the morphological and cytological characteristics of PAT were observed, showing a typical characteristic of white adipose tissue. Meanwhile, the mRNA expression of marker genes of white adipose tissue was highly expressed in PAT compared with the liver and muscle in large yellow croaker. Moreover, based on the discovery of PAT, preadipocytes from PAT were isolated, and the differentiation system of preadipocytes was established. The lipid droplet and TG content of cell were gradually increased during adipocyte differentiation. In addition, mRNA expressions of lipoprotein lipase, adipose triglyceride lipase, and transcription factors related to adipogenesis (cebpα, srebp1, pparα, and pparγ) were quantified to explain the regulation mechanism during the differentiation process. In summary, the present study first discovered perirenal adipose tissue in fish, then explored the characterization of PAT, and revealed the regulation of adipocyte differentiation. These results could advance the understanding of adipose tissue in fish and provide a novel idea for the study of the mechanism of lipid accumulation.

Exploration of the effect of blood lipids on the lesion distribution pattern in acute ischemic stroke based on MRI study with population standard spatial analysis

Objective: To explore the effect of blood lipids on the lesion distribution pattern in patients with acute ischemic stroke by using MRI technology based on population standard spatial analysis. Methods: The MRI data of 1 202 patients with acute ischemic stroke in General Hospital of Eastern Theater Command from January 2015 to December 2020 and Nanjing First Hospital from January 2013 to December 2021 were retrospectively collected, including 871 males and 331 females, aged 26 to 94 (64±11) years. According to the condition of blood lipids, they were divided into the dyslipidemia group (n=683) and the normal blood lipids group (n=519). After the automatic segmentation of diffusion-weighted imaging (DWI) images by artificial intelligence, the infarct sites were registered to the standard space which was used to draw the frequency heat map. The chi-square test was used to compare the difference in lesion location between the two groups. Generalized linear model regression analysis was used to observe the correlation between each blood lipid index and lesion site, and inter-group comparison and correlation analysis were used to observe the relationship between each blood lipid index and lesion volume. Results: Compared with the normal blood lipid group, the lesions in the dyslipidemia group were more extensive, mostly distributed in the occipital temporal region of the right posterior cerebral artery and the frontal region of the left middle cerebral artery. The brain regions of higher triglyceride(TG) and higher low-density lipoprotein cholesterol(LDL-C) groups were concentrated in the posterior circulation. The brain regions in the higher total cholesterol(TC) and lower high-density lipoprotein cholesterol(HDL-C) groups were concentrated in the anterior circulation(all P<0.05). In the anterior circulation infarct volume, the higher TC group was significantly higher than the normal TC group[(27.58±5.34) vs (17.73±1.18)ml, P=0.029]. In the posterior circulation infarct volume, the higher LDL-C group and the TG group were significantly higher than the normal LDL-C and TG groups[(7.55±2.51) vs (3.55±0.31) ml; (5.76±1.19) vs (3.36±0.30) ml](both P<0.05). Correlation analysis showed that TC and LDL-C were non-linearly (U-shaped) correlated with anterior circulation infarct volume (both P<0.05). Conclusions: Different blood lipids have effects on the distribution pattern and volume of ischemic stroke infarcts. Different hyperlipidemia is related to the specific distribution site and the larger extent of infarction.

Unraveling multi-fixel microstructure with tractography and angular weighting.

Recent advances in MRI technology have enabled richer multi-shell sequences to be implemented in diffusion MRI, allowing the investigation of both the microscopic and macroscopic organization of the brain white matter and its complex network of neural fibers. The emergence of advanced diffusion models has enabled a more detailed analysis of brain microstructure by estimating the signal received from a voxel as the combination of responses from multiple fiber populations. However, disentangling the individual microstructural properties of different macroscopic white matter tracts where those pathways intersect remains a challenge. Several approaches have been developed to assign microstructural properties to macroscopic streamlines, but often present shortcomings. ROI-based heuristics rely on averages that are not tract-specific. Global methods solve a computationally-intensive global optimization but prevent the use of microstructural properties not included in the model and often require restrictive hypotheses. Other methods use atlases that might not be adequate in population studies where the shape of white matter tracts varies significantly between patients. We introduce UNRAVEL, a framework combining the microscopic and macroscopic scales to unravel multi-fixel microstructure by utilizing tractography. The framework includes commonly-used heuristics as well as a new algorithm, estimating the microstructure of a specific white matter tract with angular weighting. Our framework grants considerable freedom as the inputs required, a set of streamlines defining a tract and a multi-fixel diffusion model estimated in each voxel, can be defined by the user. We validate our approach on synthetic data and in vivo data, including a repeated scan of a subject and a population study of children with dyslexia. In each case, we compare the estimation of microstructural properties obtained with angular weighting to other commonly-used approaches. Our framework provides estimations of the microstructure at the streamline level, volumetric maps for visualization and mean microstructural values for the whole tract. The angular weighting algorithm shows increased accuracy, robustness to uncertainties in its inputs and maintains similar or better reproducibility compared to commonly-used analysis approaches. UNRAVEL will provide researchers with a flexible and open-source tool enabling them to study the microstructure of specific white matter pathways with their diffusion model of choice.

New Zealand and Australian MRI technologists’ (radiographers) MRI safety knowledge and confidence levels

IntroductionThe MRI technologist (radiographer) is at the frontline of MRI safety decision-making and has the primary responsibility to provide high quality, efficient and safe patient care in the MRI environment. As MRI technology advances and new safety issues emerge, this study aimed to provide a snapshot of the preparedness of MRI technologists in New Zealand (NZ) and Australia to practise confidently and safely. MethodAn online questionnaire, administered via Qualtrics and covering a range of MRI safety topics, was distributed in 2018 via the New Zealand MR Users Group, the MRI Australia-NZ Group Facebook, and relevant professional bodies. ResultsA total of 312 MRI technologists attempted the questionnaire, with 246 surveys being fully completed. Of these, 61% (n = 149) were in Australia, 36% (n = 89) in NZ, and 3% (n = 8) from other countries. Findings indicated that current MRI education is preparing MRI technologists in NZ and Australia to practise safely. However, while these technologists are confident in their MRI safety decision-making, accuracy levels within some groups need addressing. ConclusionTo develop a consistent level of safe practice, it is proposed that a minimum level of MRI-specific education is defined and mandated to practise. Continuing professional development focussing on MRI safety must be encouraged and, if audited as part of registration, could also be mandated. Implementation of a supporting regulatory framework similar to NZ is recommended for other countries. Implications for practiceAll MRI technologists are responsible for the safety of their patients and staff. Employers must support and ensure MRI-specific education has been completed. Ongoing engagement in MRI safety events provided by MRI safety experts, professional bodies and/or universities is essential to remain up-to-date.

Movement patterns in tuba playing: comparison of an embouchure dystonia case with healthy professional tuba players using real-time MRI imaging.

Musculoskeletal problems in professional brass musicians are very common and often involve the muscles of the embouchure. In rare cases, embouchure dystonia (EmD), a task-specific movement disorder with a wide symptomatic and phenotypic variability, occurs. Following trumpeters and horn players, professional tuba players with and without EmD have now been studied using the latest real-time MRI technology to better understand the underlying pathophysiology. In the present study, the tongue movement patterns of 11 healthy professional artists and one subject suffering from EmD were compared. The tongue position in the anterior, intermediary and posterior oral cavity were converted into pixel positions based on seven previously generated profile lines, using the established software MATLAB. These data allow a structured comparison of tongue movement patterns between the patient and the healthy subjects, as well as between individual exercises. The main focus of the analysis was on an ascending 7-note harmonic series performed in different playing techniques (slurred, tongued, tenuto and staccato). Playing the ascending harmonics, a noticeable ascending tongue movement could be observed in the anterior part of the oral cavity in healthy tubists. In the posterior region, there was a slight decrease in oral cavity space. In the EmD patient, hardly any movement was observed at the tongue apex, but in the middle and posterior regions of the oral cavity there was an increase in size the higher the tone became. These distinct differences are relevant for the characterization and a better understanding of the clinical presentation of EmD. Concerning different playing techniques, it was apparent, that notes played slurred or staccato resulted in a larger oral cavity when compared to notes played tongued or tenuto, respectively. By using real-time MRI videos, the tongue movements of tuba players can be clearly observed and analyzed. The differences between healthy and diseased tuba players demonstrate the great effects of movement disorders in a small area of the tongue. In order to better understand the compensation of this motor control dysfunction, further studies should investigate further parameters of tone production in all brass players with a larger number of EmD patients additional to the observed movement patterns.

A Systematic Review of Treatment of cerebral cavernous malformations

Introduction: Cerebral cavernous malformations (CMs), also known as cavernomas, are brain vascular anomalies that consist of clusters of aberrant, hyalinized capillaries surrounded by hemosiderin deposits and a gliotic border. CMs are also known as cavernomas. The vasculature is filled with blood and can exhibit varying degrees of thrombosis. The familial form of CMs is inherited in an autosomal dominant manner and is caused by a heterozygous mutation in one of the three genes, CCM1, CCM2, and CCM3, which may be located on the 7q, 7p, and 3p chromosomes, respectively. This type of CMs affects only one member of the immediate family. Patients diagnosed with CMs make up anywhere from forty to sixty percent of those who have the familial variety. Treatment options for CM lesions include microsurgery, stereotactic radiosurgery, and conservative care. The most common procedure is called a microsurgical resection. Method: The aim of study of this study to investigate the treatment of cerebral cavernous malformations. This study used the literature review method by discovering articles using the search engine PubMed and SagePub and 6 articles met the inclusion criteria in this study. Result: According to the findings of the study, there were no significant variations in patient outcomes in terms of the frequency of seizures between those patients who had surgery and those who received conservative medicinal treatment. Discussion: Cavernous malformations are intracerebral anomalies that were only brought to our attention in a meaningful way after the development of MRI technology. They are relatively frequent. Treatment includes microsurgery and radiosurgery. Microsurgery cures the patient but has substantial problems with complications, deterioration and partial removal. Cavernomas that were previously inoperable can now be treated with stereotactic radiosurgery. More research is required to fully understand the long-term neurological implications of SRS. In order to evaluate the efficacy of cavernoma treatments, the natural history of the tumors must be investigated. Conclusion: Microsurgery, stereotactic radiosurgery, and conservative management treat CM lesions. Microsurgical resection is most common. Stereotactic radiosurgery can now treat inoperable cavernomas. SRS's long-term neurological effects need further study. The natural history of cavernomas must be studied to determine therapeutic success.

Secure NIfTI Image Authentication Scheme for Modern Healthcare System

Advances in digital neuroimaging technologies, i.e., MRI and CT scan technology, have radically changed illness diagnosis in the global healthcare system. Digital imaging technologies produce NIfTI images after scanning the patient’s body. COVID-19 spared on a worldwide effort to detect the lung infection. CT scans have been performed on billions of COVID-19 patients in recent years, resulting in a massive amount of NIfTI images being produced and communicated over the internet for diagnosis. The dissemination of these medical photographs over the internet has resulted in a significant problem for the healthcare system to maintain its integrity, protect its intellectual property rights, and address other ethical considerations. Another significant issue is how radiologists recognize tempered medical images, sometimes leading to the wrong diagnosis. Thus, the healthcare system requires a robust and reliable watermarking method for these images. Several image watermarking approaches for .jpg, .dcm, .png, .bmp, and other image formats have been developed, but no substantial contribution to NIfTI images (.nii format) has been made. This research suggests a hybrid watermarking method for NIfTI images that employs Slantlet Transform (SLT), Lifting Wavelet Transform (LWT), and Arnold Cat Map. The suggested technique performed well against various attacks. Compared to earlier approaches, the results show that this method is more robust and invisible.

ACPSEM position paper on ROMP scope of practice and staffing levels for magnetic resonance linear accelerators

The purpose of this position paper is to outline the ACPSEM recommendations on Medical Physicist scope of practice and staffing levels, as they relate to the use of dedicated MRI-Linacs in the treatment of patients. A core function of Medical Physicists is to safely implement changes in medical practice via the introduction of new technology and to ensure high quality radiation oncology services are provided to patients. Determining the feasibility of MRI-Linacs in any existing setting, or in establishing a new site, mandates the knowledge and services of Radiation Oncology Medical Physicists (ROMPs) as the Qualified Experts within this setting. ROMPs are key members of the multi-disciplinary team which will be required to steer the successful establishment of MRI Linac infrastructure within departments. To support efficient implementation, ROMPs must be embedded in the process from the start, including any feasibility study, initiation of the project, and development of the business case. ROMPs must be retained throughout all stages of acquisition, service development, and ongoing clinical use and expansion. The number of MRI-Linacs in Australia and New Zealand is growing. This expansion is occurring in parallel with rapid technological evolution, expanding tumour stream applications, and increasing consumer uptake. Growth and applications of MRI-Linac therapy will continue to occur beyond current known horizons, via development on the MR-Linac platform itself and through the migration of learning from this platform to conventional Linacs (known horizons for example include the use of daily, online image guided adaptive radiotherapy and MRI data informing decision making for planning and treatment before and throughout treatment courses). Clinical use, research and development will be a significant component of expanding patient access to MRI-Linac treatment and there will be an ongoing need to attract and retain ROMPs to initially establish services and in particular to drive service development and delivery for the life of the Linacs. MRI and Linac technologies mean it is necessary to perform a specialized workforce assessment for these devices, distinct from those employed for conventional Linacs and associated services. MRI-Linacs are complex, have a heightened risk profile compared to standard Linacs, and are unique in their treatment of patients. Accordingly, the workforce needs for MRI-Linacs are greater than for standard Linacs. To ensure safe and high-quality Radiation Oncology patient services are provided, it is recommended that staffing levels should be based on the 2021 ACPSEM Australian Radiation Workforce model and calculator using the MRI-Linac specific ROMP workforce modelling guidelines outlined in this paper. The ACPSEM workforce model and calculator are closely aligned with other Australian/New Zealand and international benchmarks.

Cardiac MRI: State of the Art.

Cardiac MRI plays an important role in the evaluation of cardiovascular diseases (CVDs), including ischemic heart disease, cardiomyopathy, valvular disease, congenital disease, pericardial disease, and masses. Large multicenter trials have shown the positive impact of MRI-based management on outcomes in several CVDs. These results have made MRI an indispensable technique in the evaluation of these diseases, and cardiac MRI has an important role in multisociety guidelines. MRI is the reference standard for quantification of ventricular volumes and function. Flow imaging enables accurate quantification of flow and velocities through valves, shunts, and surgical conduits or baffles. Late gadolinium enhancement and parametric mapping techniques enable tissue characterization and yield prognostic information. In the past decade, cardiac MRI technology has seen rapid advances in both hardware and sequences. Multiple novel sequences, such as parametric mapping and four-dimensional flow, are increasingly being incorporated into routine clinical practice. Acceleration strategies have matured, allowing faster acquisition of cardiac MRI sequences in patients with arrhythmia and poor breath holding. Challenges of cardiac MRI at high-field-strength magnets and in patients with indwelling cardiac devices or severe renal dysfunction have been mitigated. Artificial intelligence techniques are decreasing the complexity of MRI acquisition and postprocessing. This article reviews the current state of the art and emerging techniques in cardiac MRI.

Watch-and-Wait Approach to Rectal Cancer: The Role of Imaging.

The diagnosis and treatment of rectal cancer have evolved dramatically over the past several decades. At the same time, its incidence has increased in younger populations. This review will inform the reader of advances in both diagnosis and treatment. These advances have led to the watch-and-wait approach, otherwise known as nonsurgical management. This review briefly outlines changes in medical and surgical treatment, advances in MRI technology and interpretation, and landmark studies or trials that have led to this exciting juncture. Herein, the authors delve into current state-of-the-art methods to assess response to treatment with MRI and endoscopy. Currently, these methods for avoiding surgery can be used to detect a complete clinical response in as many as 50% of patients with rectal cancer. Finally, the limitations of imaging and endoscopy and future challenges will be discussed.

Development of an ultrafast brain MR neuronavigation protocol for ventricular shunt placement.

Advancements in MRI technology have provided improved ways to acquire imaging data and to more seamlessly incorporate MRI into modern pediatric surgical practice. One such situation is image-guided navigation for pediatric neurosurgical procedures, including intracranial catheter placement. Image-guided surgery (IGS) requires acquisition of CT or MR images, but the former carries the risk of ionizing radiation and the latter is associated with long scan times and often requires pediatric patients to be sedated. The objective of this project was to circumvent the use of CT and standard-sequence MRI in ventricular neuronavigation by investigating the use of fast MR sequences on the basis of 3 criteria: scan duration comparable to that of CT acquisition, visualization of ventricular morphology, and image registration with surface renderings comparable to standard of care. The aim of this work was to report image development, implementation, and results of registration accuracy testing in healthy subjects. The authors formulated 11 candidate MR sequences on the basis of the standard IGS protocol, and various scan parameters were modified, such as k-space readout direction, partial k-space acquisition, sparse sampling of k-space (i.e., compressed sensing), in-plane spatial resolution, and slice thickness. To evaluate registration accuracy, the authors calculated target registration error (TRE). A candidate sequence was selected for further evaluation in 10 healthy subjects. The authors identified a candidate imaging protocol, termed presurgical imaging with compressed sensing for time optimization (PICO). Acquisition of the PICO protocol takes 25 seconds. The authors demonstrated noninferior TRE for PICO (3.00 ± 0.19 mm) in comparison with the default MRI neuronavigation protocol (3.35 ± 0.20 mm, p = 0.20). The developed and tested sequence of this work allowed accurate intraoperative image registration and provided sufficient parenchymal contrast for visualization of ventricular anatomy. Further investigations will evaluate use of the PICO protocol as a substitute for CT and conventional MRI protocols in ventricular neuronavigation.

Comparison of ZOOMit-DWI sequence and conventional DWI sequence in endometrial cancer.

Magnetic resonance diffusion-weighted imaging (DWI) has important clinical value in diagnosis and curative effect evaluation on endometrial carcinoma. How to improve the detection rate of endometrial small lesions by DWI is the research focus of MRI technology. This study aims to analyze the image quality of small field MRI ZOOMit-DWI sequence and conventional single-shot echo-planar imaging (SS-EPI) DWI sequence in the scanning of endometrial carcinoma, and to explore the clinical value of ZOOMit-DWI sequence. A total of 37 patients with endometrial carcinoma diagnosed by operation and pathology in the Second Xiangya Hospital of Central South University from July 2019 to May 2021 were collected. All patients were scanned with MRI ZOOMit-DWI sequence and SS-EPI DWI sequence before operation. Two radiologists subjectively evaluated the anatomical details, artifacts, geometric deformation and focus definition of the 2 groups of DWI images. At the same time, the signal intensity were measured and the signal-to-noise ratio (SNR), contrast to noise ratio (CNR), and apparent diffusion coefficient (ADC) of the 2 DWI sequences were calculated for objective evaluation. The differences of subjective score, objective score and ADC value of the 2 DWI sequences were analyzed. The SNR of the ZOOMit-DWI group was significantly higher than that of the SS-EPI DWI group (301.96±141.85 vs 94.66±41.26), and the CNR of the ZOOMit-DWI group was significantly higher than that of the SS-EPI DWI group (185.05±105.45 vs 57.91±31.54, P<0.05). There was no significant difference in noise standard deviation between the ZOOMit-DWI group and the SS-EPI DWI group (P>0.05). The subjective score of anatomical detail and focus definition in the ZOOMit-DWI group was significantly higher than that of the SS-EPI DWI group (both P<0.05). The subjective score of artifacts and geometric deformation of ZOOMit-DWI group was significantly lower than that of the SS-EPI DWI group (both P<0.05). ADC had no significant difference between the ZOOMit-DWI group and the SS-EPI DWI group (P>0.05). The image quality of ZOOMit-DWI is significantly higher than that of conventional SS-EPI DWI. In the MRI DWI examination of endometrial carcinoma, ZOOMit-DWI can effectively reduce the geometric deformation and artifacts of the image, which is more conducive to clinical diagnosis and treatment.

Arterial Spin Labeling: Techniques, Clinical Applications, and Interpretation.

Arterial spin labeling (ASL) is an emerging noninvasive MRI technique for assessing cerebral perfusion. An important advantage of ASL perfusion is the lack of a requirement for an exogenous tracer. ASL uses magnetically labeled water protons from arterial blood as an endogenous diffusible tracer. For this reason, ASL is an attractive perfusion imaging modality for children and for patients with contraindications or adverse reactions to gadolinium, patients with renal failure, and those who need repeated follow-up imaging. Another advantage of ASL is the possibility of quantifying cerebral blood flow, which provides an opportunity for comparative analysis among multiple longitudinal studies, unlike other MR perfusion techniques, which are semiquantitative and yield relative perfusion parameters. Advances in MRI technology and pulse sequence design have translated ASL beyond the research arena to successful clinical implementation. However, ASL is still underused in routine clinical practice. Some disadvantages of ASL include a lower signal-to-noise ratio and a longer acquisition time than those with dynamic susceptibility contrast-enhanced MRI. Additional factors limiting the use of ASL include variations in existing techniques and pulse sequence design, the complexity of implementation and postprocessing, insufficient experience with and/or knowledge of the potential clinical applications, and the absence of interpretation guidelines. The authors review the technical and physiologic basis of ASL perfusion, as well as artifacts, pitfalls, and its current clinical applications. A practical approach for interpreting ASL findings is also suggested.

Role of Image-Guided Focal Cryoablation in Localized Prostate Cancer

Prostate cancer is the most common non-cutaneous malignancy in men, with the majority of newly diagnosed clinical scenarios eligible for active surveillance. However, there may be psychological ramifications associated with living with an untreated malignancy. Furthermore, recent reports show long-term progression exceeds 50% even for low-risk disease. Given the morbidity of traditional whole-gland prostate cancer therapies further advancements are necessary to maximize cure and minimize treatment side effects. Advances in multiparametric MRI has enabled a paradigm shift not only in the detection of clinically significant disease, but also toward more specific disease localization. While traditional treatments for prostate cancer involve whole-gland treatment, contemporary MRI technology allows for consideration of focal ablation via various technologies. This review details focal cryoablation for primary and salvage prostate cancer treatments and compares its efficacy to other treatment methods, including brachytherapy, external beam radiation, and high intensity focused ultrasound. The use of focal cryoablation as a primary treatment has shown promising oncologic outcomes, similar to that of whole-gland cryoablation, but with better functional outcomes. Focal cryotherapy as a salvage treatment has mixed results regarding efficacy and warrants further study. When compared to other focal treatments, cryotherapy leads to similar, or better, oncologic control outcomes. In addition, the review details the considerations for adjunct therapies and future applications to enhance the precision accuracy of current focal cryoablation techniques.

Fluorinated hydrogel nanoparticles with regulable fluorine contents and T2 relaxation times as 19F MRI contrast agents.

Medical imaging contrast agents that are able to provide detailed biological information have attracted increasing attention. Among the new emerging imaging contrast agents, 19F magnetic resonance imaging contrast agents (19F MRI CAs) are extremely promising for their weak background disturbing signal from the body. However, to prepare 19F MRI CAs with a long T2 relaxation time and excellent biocompatibility in a simple and highly effective strategy is still a challenge. Herein, we report a new type of 19F MRI hydrogel nanocontrast agents (19F MRI HNCAs) synthesized by a surfactant-free emulsion polymerization with commercial fluorinated monomers. The T2 relaxation time of 19F MRI HNCA-1 was found to be 25-40 ms, guaranteeing its good imaging ability in vitro. In addition, according to an investigation into the relationship between the fluorine content and 19F MRI signal intensity, the 19F MRI signal intensity was not only determined by the fluorine content in 19F MRI HNCAs but also by the hydration microenvironment around the fluorine atoms. Moreover, 19F MRI HNCAs demonstrated excellent biocompatibility and imaging capability inside cells. The primary exploration demonstrated that 19F MRI HNCAs as a new type of 19F MRI contrast agent hold potential for imaging lesion sites and tracking cells in vivo by 19F MRI technology.

Magnetic Resonance Imaging and Iron-oxide Nanoparticles in the era of Personalized Medicine.

Medical imaging is an important factor for diagnosis. It can be used to diagnose patients, differentiate disease stages, and monitor treatment regimens. Although different imaging technologies are available, MRI is sensitive over other imaging modalities as it is capable of deep tissue penetration allowing to image the anatomical, structural, and molecular level of diseased organs. Thus, it can be used as screening tool for disease staging. One of the important components of imaging is contrast agents which are used to increase the sensitivity of MRI technology. While different types of contrast agents are available, iron-oxide based nanoparticles (IONPS) are widely used as these are easy to formulate, functionalize, biocompatible and cost effective. In addition to its use as contrast agents, these have been used as drug carriers for the treatment of different types of diseases ranging from cancer, cardiovascular diseases, neurological disorders, autoimmune diseases, and infectious diseases. For the last two decades, there has been advancement in nanotheranostics, where IONPs are formulated to carry drug and be used as contrast agents in one system so that these can be used for image-guided therapy and monitor real-life treatment response in diseased tissue. This technology can be used to stratify patients into responders and non-responders and reduce adverse drug toxicity and lead to a tailored treatment. However, success of nanotheranostics depends on several factor, including identification of disease associated biomarkers that can be targeted on IONPs during formulation. While many challenges exist for the clinical translation of nanotheranostics, it still has the potential to be implemented in personalized treatment strategy. In this review article, we discussed the use of MRI technology and IONPs in relation to their application in disease diagnosis and nanotheranostics application in personalized medicine.

Better neural images by combining ultrahigh field strength MRI with innovative MRI sequences

Better MRI scanning technologies and protocols can provide insights into neurological disorders. In this review, we describe the basic concepts of MRI and, in the process, we convey to the reader the relevance of MRI as a high-resolution imaging modality of tissue structure and metabolism. We outline the main parameters for improving MRI resolution and sensitivity for the ultimate goal of optimizing the diagnosis of neurological diseases. A key to obtaining high-resolution images by MRI is the strength of the magnet’s external field strength (Bo). The higher the field strength, the better the signal-to-noise (SNR) of acquired signals. Hence, this results in improved sensitivity and resolution of the reconstructed images. This article recapitulates the advancement of MRI technology towards Ultra-High-Field Strength (UHF) apparatus and the consequent benefits in SNR. Other keys towards improving MRI images include deftly modifying the parameters of longitudinal magnetization relaxation time (T1), transverse magnetization relaxation time (T2), repetition times between radiofrequency (RF) pulses (TR), and the time of reading post-pulse (TE). Such parameters can be controlled through acquisition software associated with the MRI machines. The review profiles the cumulative efforts by researchers to complement UHF-MRI hardware with innovative RF pulse sequences protocols such as Diffusion Weighted Imaging (DWI), Pulse Gradient Spin Echo (PGSE), Oscillating Gradient Spin Echo (OGSE), Blood Oxygen Level Dependent (BOLD)-MRI and Arterial Spin Label (ASL)-MRI. Collectively, these advances in both MRI hardware and software have pushed the field to attain a mesoscopic level of resolution. Further enhancements in analyzing MRI images through Artificial Intelligence (AI) algorithms may advance resolutions beyond the mesoscopic stage and perhaps even toward the microscopic resolution of living tissue.

Holmium Complex with Phospholipids as 1H NMR Relaxational Sensor of Temperature and Viscosity.

The sensitivity of Ho–phospholipid complexes to changes in the membrane viscosity of liposomes was checked. An increase in viscosity was observed for DPPC and DMPC near the phase-transition temperature. Ho–phospholipid complexes could be used as sensors of local membrane viscosity in NMR and MRI technologies.

Iron-Based Magnetic Nanosystems for Diagnostic Imaging and Drug Delivery: Towards Transformative Biomedical Applications.

The advancement of biomedicine in a socioeconomically sustainable manner while achieving efficient patient-care is imperative to the health and well-being of society. Magnetic systems consisting of iron based nanosized components have gained prominence among researchers in a multitude of biomedical applications. This review focuses on recent trends in the areas of diagnostic imaging and drug delivery that have benefited from iron-incorporated nanosystems, especially in cancer treatment, diagnosis and wound care applications. Discussion on imaging will emphasise on developments in MRI technology and hyperthermia based diagnosis, while advanced material synthesis and targeted, triggered transport will be the focus for drug delivery. Insights onto the challenges in transforming these technologies into day-to-day applications will also be explored with perceptions onto potential for patient-centred healthcare.