Cardiac functional magnetic resonance imaging at 7T:Image quality optimization and ultra-high field capabilities

BACKGROUND 7T cardiac magnetic resonance imaging(MRI)introduces several advantages,as well as some limitations,compared to lower-field imaging.The capabilities of ultra-high field(UHF)MRI have not been fully exploited in cardiac functional imaging.AIM To optimize 7T cardiac MRI functional imaging without the need for conducting B1 shimming or subject-specific tuning,which improves scan efficiency.In this study,we provide results from phantom and in vivo scans using a multi-channel transceiver modular coil.METHODS We investigated the effects of adding a dielectric pad at different locations next to the imaged region of interest on improving image quality in subjects with different body habitus.We also investigated the effects of adjusting the imaging flip angle in cine and tagging sequences on improving image quality,B1 field homogeneity,signal-to-noise ratio(SNR),blood-myocardium contrast-to-noise ratio(CNR),and tagging persistence throughout the cardiac cycle.RESULTS The results showed the capability of achieving improved image quality with high spatial resolution(0.75 mm×0.75 mm×2 mm),high temporal resolution(20 ms),and increased tagging persistence(for up to 1200 ms cardiac cycle duration)at 7T cardiac MRI after adjusting scan set-up and imaging parameters.Adjusting the imaging flip angle was essential for achieving optimal SNR and myocardium-toblood CNR.Placing a dielectric pad at the anterior left position of the chest resulted in improved B1 homogeneity compared to other positions,especially in subjects with small chest size.CONCLUSION Improved regional and global cardiac functional imaging can be achieved at 7T MRI through simple scan set-up adjustment and imaging parameter optimization,which would allow for more streamlined and efficient UHF cardiac MRI.

Application of nuclear magnetic resonance technology to carbon capture,utilization and storage:A review

Carbon capture,utilization and storage (CCUS) is considered as a very important technology for mitigating global climate change.Carbon dioxide (CO2) injected into an underground reservoir will induce changes in its physical properties and the migration of CO2 will be affected by many factors.Accurately understanding these changes and migration characteristics of CO2 is crucial for selecting a CCUS project site,estimating storage capacity and ensuring storage security.In this paper,the basic principles of nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) technologies are briefly introduced in the context of laboratory experiments related to CCUS.The types of NMR apparatus,experimental samples and testing approaches applied worldwide are discussed and analyzed.Then two typical NMR core analysis systems used in CCUS field and a self-developed high-pressure,low-field NMR rock core flooding experimental system are compared.Finally,a summary of the current deficiencies related to NMR applied to CCUS field is given and future research plans are proposed.

7.0T nuclear magnetic resonance evaluation of the amyloid beta(1–40) animal model of Alzheimer's disease: comparison of cytology verification

3.0T magnetic resonance spectroscopic imaging brain function in Alzheimer＇s disease. However, is a commonly used method in the research ot the role of 7.0T high-field magnetic resonance spectroscopic imaging in brain function of Alzheimer＇s disease remains unclear. In this study, 7.0T magnetic resonance spectroscopy showed that in the hippocampus of Alzheimer＇s disease rats, the N-acetylaspartate wave crest was reduced, and the creatine and choline wave crest was elevated. This finding was further supported by hematoxylin-eosin staining, which showed a loss of hippocampal neurons and more glial cells. Moreover, electron microscopy showed neuronal shrinkage and mitochondrial rupture, and scanning electron microscopy revealed small size hippocampal synaptic vesicles, incomplete synaptic structure, and reduced number. Overall, the results revealed that 7.0T high-field nuclear magnetic resonance spectroscopy detected the lesions and functional changes in hippocampal neurons of Alzheimer＇s disease rats in vivo, allowing the possibility for assessing the success rate and grading of the amyloid beta （1-40） animal model of Alzheimer＇s disease.

Nuclear magnetic resonance study of the formation and dissociation process of nature gas hydrate in sandstone

In this work,the authors monitored the formation and dissociation process of methane hydrate in four different rock core samples through nuclear magnetic resonance(NMR)relaxation time(T_(2))and 2D imaging measurement.The result shows that the intensity of T_(2) spectra and magnetic resonance imaging(MRI)signals gradually decreases in the hydrate formation process,and at the same time,the T_(2) spectra move toward the left domain as the growth of hydrate in the pores of the sample accelerates the decay rate.The hydrate grows and dissociates preferentially in the purer sandstone samples with larger pore size and higher porosity.Significantly,for the sample with lower porosity and higher argillaceous content,the intensity of the T_(2) spectra also shows a trend of a great decrease in the hydrate formation process,which means that high-saturation gas hydrate can also be formed in the sample with higher argillaceous content.The changes in MRI of the sample in the process show that the formation and dissociation of methane hydrate can reshape the distribution of water in the pores.

Structural control of magnetic nanoparticles for positive nuclear magnetic resonance imaging

In addition to the tens of millions of medical doses consumed annually around the world,a vast number of nuclear magnetic resonance imaging(MRI)contrast agents are being deployed in MRI research and development,offering precise diagnostic information,targeting capabilities,and analyte sensing.Superparamagnetic iron oxide nanoparticles(SPIONs)are notable among these agents,providing effective and versatile MRI applications while also being heavy-metal-free,bioconjugatable,and theranostic.We designed and implemented a novel two-pronged computational and experimental strategy to meet the demand for the efficient and rigorous development of SPION-based MRI agents.Our MATLAB-based modeling simulation and magnetic characterization revealed that extremely small maghemite SPIONs in the 1-3 nm range possess significantly reduced transversal relaxation rates(R_(2))and are therefore preferred for positive(T_(1)-weighted)MRI.Moreover,X-ray diffraction and X-ray absorption fine structure analyses demonstrated that the diffraction pattern and radial distribution function of our SPIONs matched those of the targeted maghemite crystals.In addition,simulations of the X-ray near-edge structure spectra indicated that our synthesized SPIONs,even at 1 nm,maintained a spherical structure.Furthermore,in vitro and in vivo MRI investigations showed that our 1-nm SPIONs effectively highlighted whole-body blood vessels and major organs in mice and could be cleared through the kidney route to minimize potential post-imaging side effects.Overall,our innovative approach enabled a swift discovery of the desired SPION structure,followed by targeted synthesis,synchrotron radiation spectroscopic studies,and MRI evaluations.The efficient and rigorous development of our high-performance SPIONs can set the stage for a computational and experimental platform for the development of future MRI agents.

Multi-modality parathyroid imaging:A shifting paradigm

The goal of parathyroid imaging in hyperparathyroidism is not diagnosis,rather it is the localization of the cause of hyperparathyroidism for planning the best therapeutic approach.Hence,the role of imaging to accurately and precisely localize the abnormal parathyroid tissue is more important than ever to facilitate minimally invasive parathyroidectomy over bilateral neck exploration.The common causes include solitary parathyroid adenoma,multiple parathyroid adenomas,parathyroid hyperplasia and parathyroid carcinoma.It is highly imperative for the radiologist to be cautious of the mimics of parathyroid lesions like thyroid nodules and lymph nodes and be able to differentiate them on imaging.The various imaging modalities available include high resolution ultrasound of the neck,nuclear imaging studies,four-dimensional computed tomography(4D CT)and magnetic resonance imaging.Contrast enhanced ultrasound is a novel technique which has been recently added to the armam-entarium to differentiate between parathyroid adenomas and its mimics.Through this review article we wish to review the imaging features of parathyroid lesions on various imaging modalities and present an algorithm to guide their radiological differentiation from mimics.

Multimodality imaging and treatment of paranasal sinuses nuclear protein in testis carcinoma:A case report

BACKGROUND Nuclear protein in testis(NUT) carcinoma is a rare aggressive malignant epithelial cell tumor, previously known as NUT midline carcinoma(NMC), characterized by an acquired rearrangement of the gene encoding NUT on chromosome 15q14. Due to the lack of characteristic pathological features, it is often underdiagnosed and misdiagnosed. A variety of methods can be used to diagnose NMC, including immunohistochemistry, karyotyping, fluorescence in situ hybridization, reverse transcription-polymerase chain reaction, and next-generation sequencing. So far, there is no standard treatment plan for NMC and the prognosis is poor, related to its rapid progression, easy recurrence, and unsatisfactory treatment outcome.CASE SUMMARY A 58-year-old female came to our hospital with a complaint of eye swelling and pain for 8 d. The diagnosis of NMC was confirmed after postoperative pathology and genetic testing. The patient developed nausea and vomiting, headache, and loss of vision in both eyes to blindness after surgery. Magnetic resonance imaging(MRI) and positron emission tomography/computed tomography(PET/CT) performed after 1.5 mo postoperatively suggested tumor recurrence. The patient obtained remission after radiation therapy to some extent and after initial treatment with anti-angiogenic drugs and sonodynamic therapy(SDT), but cannot achieve long-term stability and eventually developed distant metastases, with an overall survival of only 17 mo.CONCLUSION For patients with rapidly progressing sinus tumors and poor response to initial treatment, the possibility of NMC should be considered and immunohistochemical staining with anti-NUT should be performed as soon as possible, combined with genetic testing if necessary. CT, MRI, and PET/CT imaging are essential for the staging, management, treatment response assessment and monitoring of NMC. This case is the first attempt to apply heat therapy and SDT in the treatment of NMC, unfortunately, the prognosis remained poor.

Role of functional imaging in the development and refinement of invasive neuromodulation for psychiatric disorders

Deep brain stimulation(DBS) is emerging as a pow-erful tool for the alleviation of targeted symptoms in treatment-resistant neuropsychiatric disorders. Despite the expanding use of neuropsychiatric DBS, the mecha-nisms responsible for its effects are only starting to be elucidated. Several modalities such as quantitative elec-troencephalography as well a intraoperative recordings have been utilized to attempt to understand the under-pinnings of this new treatment modality, but functional imaging appears to offer several unique advantages. Functional imaging techniques like positron emission tomography, single photon emission computed tomog-raphy and functional magnetic resonance imaging have been used to examine the effects of focal DBS on activ-ity in a distributed neural network. These investigations are critical for advancing the field of invasive neuro-modulation in a safe and effective manner, particularly in terms of defining the neuroanatomical targets and refining the stimulation protocols. The purpose of this review is to summarize the current functional neuroim-aging findings from neuropsychiatric DBS implantation for three disorders: treatment-resistant depression, obsessive-compulsive disorder, and Tourette syndrome. All of the major targets will be discussed(Nucleus ac-cumbens, anterior limb of internal capsule, subcallosal cingulate, Subthalamic nucleus, Centromedial nucleus of the thalamus-Parafasicular complex, frontal pole, and dorsolateral prefrontal cortex). We will also address some apparent inconsistencies within this literature, and suggest potential future directions for this promis-ing area.

Two-state kinetics characterized by image analysis of nuclear magnetic resonance spectra

Nuclear magnetic resonance (NMR) spectros-copy has become an important tool in modern biological research. NMR spectra image analysis can be used to analyze the kinetics of biomacromolecular conformational changes. The relationship between the image parameters and the protein dynamics was investigated by using a small globular protein ω-conotoxin SO3 (ω-CTX SO3). The physical meanings of the image parameters were characterized from the results. Comparison of the data from the traditional integral area of specific resonance peaks method and the NMR image analysis method showed the advantages of using NMR spectra image analysis for kinetic analysis of two-state processes monitored by 1D proton NMR.

Multi-modality imaging of cardiac amyloidosis: Contemporary update

Cardiac amyloidosis is a heterogeneous and challenging diagnostic disease with poor prognosis that is now being altered by introduction of new therapies.Echocardiography remains the first-line imaging tool, and when disease is suspected on echocardiography, cardiac magnetic resonance imaging and nuclear imaging play critical roles in the non-invasive diagnosis and evaluation of cardiac amyloidosis. Advances in multi-modality cardiac imaging allowing earlier diagnosis and initiation of novel therapies have significantly improved the outcomes in these patients. Cardiac imaging also plays important roles in the risk stratification of patients presenting with cardiac amyloidosis. In the current review, we provide a clinical and imaging focused update, and importantly outline the imaging protocols, diagnostic and prognostic utility of multimodality cardiac imaging in the assessment of cardiac amyloidosis.

Diagnostic and prognostic value of cardiac imaging in amyloidosis

Amyloidosis is an infiltrative disease caused by extracellular protein deposition that has accumulated a lot of scientific production in recent years.Different types of amyloidosis can affect the heart.Transthyretin amyloidosis and light chain amyloidosis are the two most common types of cardiac amyloidosis.These entities have a poor prognosis,so accurate diagnostic techniques are imperative for determining an early therapeutic approach.Recent advances in cardiac imaging and diagnostic strategies show that these tools are safe and can avoid the use of invasive diagnostic techniques to histological confirmation,such as endomyocardial biopsy.We performed a review on the diagnostic and prognostic implications of different cardiac imaging techniques in cardiac amyloidosis.We mainly focus on reviewing echocardiography,cardiac magnetic resonance,computed tomography and nuclear imaging techniques and the different safety measurements that can be done with each of them.

Multi-modality imaging in transthyretin amyloid cardiomyopathy

Transthyretin amyloid(TTR)cardiomyopathy is a disease of insidious onset,which is often accompanied by debilitating neurological and/or cardiac complications.The true prevalence is not fully known due to its elusive presentation,being often under-recognized and usually diagnosed only late in its natural history and in older patients.Because of this,effective treatment options are usually precluded by multiple comorbidities and frailty associated with such patients.Therefore,high clinical suspicion with earlier and better detection of this disease is needed.In this review,the novel applications of multimodality imaging in the diagnostic pathway of TTR cardiomyopathy are explored.These include the complimentary roles of transthoracic echocardiography,cardiac magnetic resonance,nuclear scintigraphy and positron emission tomography in quantifying cardiac dysfunction,diagnosis and risk stratification.Recent advances in novel therapeutic options for TTR have further enhanced the importance of a timely and accurate diagnosis of this disease.

“How many times must a man look up before he can really see the sky?” Rheumatic cardiovascular disease in the era of multimodality imaging

Cardiovascular involvement in rheumatic diseases(RD) is the result of various pathophysiologic mechanisms including inflammation, accelerated atherosclerosis, myocardial ischemia, due to micro- or macro-vascular lesions and fibrosis. Noninvasive cardiovascular imaging, including echocardiography, nuclear techniques, cardiovascular computed tomography and cardiovascular magnetic resonance, represents the main diagnostic tool for early, non-invasive diagnosis of heart disease in RD. However, in the era of multimodality imaging and financial crisis there is an imperative need for rational use of imaging techniques in order to obtain the maximum benefit at the lowest possible cost for the health insurance system. The oligo-asymptomatic cardiovascular presentation and the high cardiovascular mortality of RD necessitate a reliable and reproducible diagnostic approach to catch early cardiovascular involvement. Echocardiography remains the routine cornerstone of cardiovascular evaluation. However, a normal echocardiogram can not always exclude cardiac involvement and/or identify heart disease acuity and pathophysiology. Therefore, cardiovascular magnetic resonance is a necessary adjunct complementary to echocardiography, especially in new onset heart failure and when there are conflicting data from clinical, electrocardiographic and echocardiographic evaluation of RD patients.

基于不同维度低场核磁共振技术的大豆含油率检测与判别

大豆含油率的高低直接影响榨油与育种结果。为探究大豆含油率的最佳检测方法与构建含油率高低判别模型,该研究基于不同维度低场核磁共振(low field nuclear magnetic resonance,LF-NMR)技术,以国标法为对照,利用LF-NMR波谱和LF-NMR含油含水率软件检测大豆含油率;核磁共振成像(magnetic resonance imaging,MRI)结合深度学习,建立大豆含油率高低判别模型。引入低场二维核磁共振(low field two-dimensional nuclear magnetic resonance,LF-2D-NMR)技术,定性分析一维波谱中信号重叠无法区分组分的问题。试验结果表明,LF-NMR含油含水率软件能快速准确检测大豆含油率,T1-T2二维核磁图谱成功解决了自由水和油信号重叠问题。利用U-net++深度学习模型对MRI成像的矢状面、冠状面、横截面以及三面混合数据集进行训练,其中横截面评价指标与其他数据集相比更优,语义分割部分中平均交并比(mean intersection over union,mIoU)约0.9058,全局准确率0.9980,训练后的模型能够将MRI图像识别并分割,快速判别大豆含油率高低。试验证明,LF-NMR及MRI能够快速无损掌握大豆含油率信息,为大豆的高油育种提供了新思路和技术支持。

基于恒定梯度编码一维选层T_(2)谱的胶结砂岩层析成像方法

核磁共振成像是探究岩心尺度非均质性的先进技术,受岩石复杂性和编码技术影响,现有方法效果不佳。基于梯度场的二维/三维核磁共振技术成像容易但信噪比低,无梯度场的传统选层T_(2)谱(频率编码/相位编码)方法效率低。该研究提出恒定梯度编码一维选层T_(2)谱层析成像方法,做到了成像数据体量小、信噪比高且信号更完整。层析T_(2)谱图像及其热度分布,能够有效表征毛细管压力和成岩作用对流体非均匀分布的影响。饱和油状态时,T_(2)谱层间差异性反映成岩作用影响。高饱和油阶段,轴向热度图反映了低毛细管压力游离油的脱出规律。完全驱替后毛细管压力进入稳定状态,轴向热度图反映了微孔中吸附油赋存状态的差异。该技术在胶结砂岩气驱油实验中取得了良好效果,并对解析强非均质岩石渗流规律有重要作用。

基于核磁共振和鳞状细胞癌抗原预测早期宫颈鳞癌辅助放疗的模型

目的建立一个基于核磁共振和鳞状细胞癌抗原(SCCA)模型,预测早期宫颈鳞癌是否需要术后辅助放疗。方法收集2018—2021年医院收治的67例早期宫颈鳞癌(ⅠB1、ⅠB2、ⅡA1)患者的临床资料,回顾性分析病灶大小、浸润深度、组织分化程度、年龄、SCCA、表观弥散系数(ADC)值、人乳头瘤病毒(HPV)亚型与术后辅助放疗的关系。通过单因素及多因素分析,筛选出影响术后辅助放疗的独立危险因素。应用受试者工作特征(ROC)曲线求得独立危险因素的截断值,进一步构建预测模型。结果单因素分析后发现,病灶大小(P<0.001)、浸润深度(P=0.001)、组织分化程度(P=0.002)、SCCA(P<0.001)、ADC值(P<0.001)影响术后辅助放疗,二元logistic回归多因素分析后发现,病灶大小(OR=1.201,P=0.021)、SCCA(OR=1.608,P=0.033)、ADC值(OR=0.013,P=0.043)是影响辅助放疗的独立危险因素。利用ROC求得截断值分别为:SCCA=4.84μg·L^(-1),病灶=27 mm,ADC=0.907×10^(-3)mm^(2)·s^(-1)。当同时满足任意2个指标时,术后辅助放疗的比率达94.7%以上。结论肿瘤≥27 mm、ADC值≤0.907×10^(-3)mm^(2)·s^(-1)、SCCA≥4.84μg·L^(-1)可以作为判断辅助放疗的指标,若同时满足任意2个指标,辅助放疗的可能性明显增加,此时应慎重考虑治疗方式,尽量避免根治性手术及辅助放疗双重治疗模式带来的严重并发症的发生。

基于术前MRI影像组学及临床特征的卵巢癌淋巴结转移预测模型构建及验证

目的探讨卵巢癌淋巴结转移的危险因素,并构建基于术前MRI影像组学及临床特征的卵巢癌淋巴结转移的列线图。方法选取2018年2月—2021年7月期间于安徽医科大学第一附属医院就诊的225例卵巢癌患者作为研究对象,根据淋巴结转移情况分为淋巴结转移组和无淋巴结转移组。应用Logistic回归分析筛选卵巢癌淋巴结转移的危险因素。利用LIFEx软件提取卵巢癌患者手术前的核磁共振(MRI)影像组学特征,将所选MRI影像组学与其对应非零系数乘积的线性组合确定其MRI影像组学评分。建立MRI影像组学、临床特征模型。通过整合优化的MRI影像组学及临床特征模型,采用R(R4.2.0)软件建立卵巢癌淋巴结转移的列线图,并对模型进行内部验证。结果225例卵巢癌中有95例患者出现淋巴结转移,淋巴结转移的发生率为42.22%(95/225)。Logsitc回归分析结果显示,临床分期、病灶位置、分化程度及糖尿病等是卵巢癌淋巴结转移的危险因素(P<0.05)。结合多因素结果及MRI影像组学参数提取构建了3组预测模型,其中包括临床模型1组,MRI影像组学模型1组,组合模型(临床-MRI影像组学模型)1组,其中临床-MRI影像组学模型的AUC(0.862)最高。构建的临床-MRI影像组学关于卵巢癌淋巴结转移的列线图模型的结果显示,校正曲线显示预测值和实际值具有良好的拟合度,模型的ROC曲线下面积为0.862(95%CI:0.790~0.934),决策曲线显示阈值概率为22%~80%时,列线图预测卵巢癌淋巴结转移的净获益值较高。结论基于术前MRI影像组学及临床特征的卵巢癌淋巴结转移的列线图模型具有较高的准确率和较好的临床应用价值,能够用于术前卵巢癌淋巴结转移的识别。

基于广义估计方程探讨三维MRI联合CT影像学检查对膝关节骨性关节炎关节病变的诊断价值

目的探讨三维核磁共振成像(MRI)联合计算机断层扫描(CT)影像学检查对膝关节骨性关节炎关节病变、分期的诊断价值。方法 回顾性分析2019年9月至2022年9月我院收治的135例膝关节关节炎患者临床资料。比较不同成像方法与关节镜结果的一致性和诊断效能。分析不同成像方法与关节镜分期结果的相关性。比较不同影像学方法诊断关节病变的置信度。结果 三维MRI联合CT检查结果的一致性(Kappa=0.701)大于三维MRI (Kappa=0.512)或CT (Kappa=0.373)单独检查。联合检查的诊断准确率(85.93%)明显高于单独检查(77.04%、70.37%)。影像学分期结果与关节镜分期结果均呈正相关(r=0、801、0.766,P<0.01)。联合诊断关节病变的准确性及特异性明显高于单独诊断。结论 三维MRI联合CT影像学检查对膝关节骨性关节炎关节病变、分期的诊断具有较高的检出率和准确率。

基于专利的全球高端磁共振成像发展现状分析

目的从专利申请角度对全球高端磁共振成像(Magnetic Resonance Imaging,MRI)发展现状进行分析,并对国内发展状况提出针对性对策和建议。方法利用incoPat对2013—2022年全球高端MRI专利情况进行分析,从专利申请数量、质量及研究方向角度对检索到的专利进行分析,探讨国内外高端MRI技术研究态势。结果共检索到全球高端MRI相关专利申请6087件,从专利申请数量角度,我国申请数量位居世界首位,为1949件,全球占比32%,但从专利申请质量角度来看,我国的申请授权率略低,约为53.82%。全球高端MRI主要包括超高场MRI、超极化MRI、深度学习后处理的超快速MRI、多核MRI、AI+MRI和PET/MRI多模态一体化成像6个技术方向。我国的超高场、深度学习及AI、多核及超极化MRI研发实力均位于全球前列,其中中科院为主要贡献者;而我国的PET/MRI一体化MRI研发实力较弱,需进一步加强。结论国内企业要加强和中科院及高校的合作,将国家科研项目应用到产业中,促进科研成果转化,形成优势互补,提高我国在高端MRI领域的话语权。

MRI多种功能成像对前列腺病变的评估分析

目的 探析核磁共振成像(MRI)多种功能成像对前列腺病变的评估价值。方法 前瞻性纳入2020年1月至2022年1月在医院接受前列腺检查、超声检查的120例疑似前列腺癌患者为研究对象,全部患者均接受MRI弥散加权成像(DWI)、动态增强磁共振成像(DCE-MRI)及磁共振波谱成像(MRS)检查。以穿刺活检或手术病理结果为金标准,分别计算患者常规MRI、DWI、DCE-MRI、MRS及四者联合评估前列腺病变的灵敏度、特异度、阳性预测值、阴性预测值及Kappa值等。结果 穿刺活检或手术病理结果显示,120例患者中有84例确诊前列腺癌,占比为70.00%;DWI、DCE-MRI、MRS及联合评估前列腺病变一致性的Kappa值分别为0.731、0.605、0.550、0.902,较DWI、DCE-MRI、MRS单独评估,联合评估与金标准的一致性更好;相较于DWI、DCE-MRI和MRS单独评估,联合评估前列腺病变的敏感度、准确度和阴性预测值均较高(P<0.05)。结论 MRI多种功能成像均可有效评估前列腺癌,且联合评估的准确率最高,可有效提高前列腺癌的诊断准确性,诊断效能良好。