Dynamic contrast-enhanced magnetic resonance imaging: a useful tool for characterizing ovarian epithelial tumors

PURPOSE: To evaluate the utility of dynamic contrast enhancement (DCE) MRI for distinguishing among benign, borderline and invasive epithelial ovarian tumors. MATERIALS AND METHODS: We analyzed preoperative MRI studies of 37 patients with ovarian epithelial tumors (10 benign, 11 borderline, and 16 invasive). A DCE-MRI sequence was acquired and regions of interest (ROIs) were drawn in the ovarian tumors and adjacent myometrium. A total of three patterns of enhancement were defined. Dynamic data were parameterized using mathematical models that included the enhancement amplitude (EA), the time of half rising (THR), and the maximal slope (MS). Using myometrium as the internal reference, ratios of EA (EAr), THR (THRr), MS (MSr), and initial area under the curve for 60 seconds after injection (IAUC(60) ratio) were determined. RESULTS: Morphological criteria such as septa, papillary projection, solid portion, and T2-weighted MR signal intensity of solid tissue were useful for discriminating invasive from noninvasive ovarian tumors (P = 0.01, P = 0.02, P = 0.002, and P < 0.0001 respectively) but not for discriminating benign from borderline tumors. Curve type 3 was specific for invasive ovarian tumors. EAr, MSr, and IAUC(60) ratio were higher for invasive than for benign (P < 0.0001) and borderline tumors (P = 0.005, P = 0.002, and P = 0.001, respectively). The IAU(60) ratio was the most relevant factor for discriminating benign from borderline and invasive tumors. MSr and IAU(60) ratio could be combined to generate a decision tree with 81% accuracy. CONCLUSION: DCE-MRI is a useful tool for characterizing epithelial ovarian tumors.     

Cortical mapping by functional magnetic resonance imaging in patients with brain tumors

The aim of our study was to establish the effectiveness of the functional MRI (fMRI) technique in comparison with intraoperative cortical stimulation (ICS) in planning cortex-saving neurosurgical interventions. The combination of sensory and motor stimulation during fMRI experiments was used to improve the exactness of central sulcus localization. The study subjects were 30 volunteers and 33 patients with brain tumors in the rolandic area. Detailed topographical relations of activated areas in fMRI and intraoperative techniques were compared. The agreement in the location defined by the two methods for motor centers was found to be 84%; for sensory centers it was 83%. When both kinds of activation are taken into account this agreement increases to 98%. A significant relation was found between fMRI and ICS for the agreement of the distance both for motor and sensory centers (p=0.0021–0.0024). Also a strong dependence was found between the agreement of the location and the agreement of the distance for both kinds of stimulation. The spatial correlation between fMRI and ICS methods for the sensorimotor cortex is very high. fMRI combining functional and structural information is very helpful for preoperative neurosurgical planning. The sensitivity of the fMRI technique in brain mapping increases when using both motor and sensory paradigms in the same patient.     

Three-dimensional J-resolved H-1 magnetic resonance spectroscopic imaging of volunteers and patients with brain tumors at 3T.

A method that combines two-dimensional (2D) J-resolved spectroscopy with three spatial dimension magnetic resonance spectroscopic imaging (MRSI) is introduced to measure J-coupled metabolites of glutamate (Glu), glutamine (Gln), myo-Inositol (mI), and lactate (Lac) in the brain and to simultaneously obtain T(2) values of choline (Cho), creatine (Cr), and N-acetyl aspartate (NAA). Relatively few points in the t(1) dimension (six echo times) and a flyback echo-planar trajectory were incorporated in the acquisition to speed up the total acquisition time so that it was within a clinically feasible range (23 min). Data obtained using GAMMA software simulations and from phantoms have shown that the (4)CH(2) resonances of Glu can be separated from Gln at 2.35 ppm in TE-averaged spectra. Results from phantoms, six normal volunteers, and four patients demonstrated good signal-to-noise ratio (SNR). The J cross-peaks from the methyl group of Lac were visualized in the 2D spectra from the phantom and the glioma patient, and could be quantified from the spectra at J = +/-4.17 Hz. This technique also enables the evaluation of the changes in metabolite T(2). Compared with the values in normal white matter, the T(2) values of Cho and Cr were statistically significantly increased in regions of glioma.     

Advanced magnetic resonance imaging findings in salivary gland tumors

Salivary gland tumors (SGTs) make up a small portion (approximately 5%) of all head and neck tumors. Most of them are located in the parotid glands, while they are less frequently located in the submandibular glands, minor salivary glands or sublingual gland. The incidence of malignant or benign tumors (BTs) in the salivary glands varies according to the salivary gland from which they originate. While most of those detected in the parotid gland tend to be benign, the incidence of malignancy increases in other glands. The use of magnetic resonance imaging (MRI) in the diagnosis of SGTs is increasing every day. While conventional sequences provide sufficient data on the presence, localization, extent and number of the tumor, they are insufficient for tumor specification. With the widespread use of advanced techniques such as diffusion-weighted imaging, semi-quantitative and quantitative perfusion MRI, studies and data have been published on the differentiation of malignant or BTs and the specificity of their subtypes. With diffusion MRI, differentiation can be made by utilizing the cellularity and microstructural properties of tumors. For example, SGTs such as high cellular Warthin’s tumor (WT) or lymphoma on diffusion MRI have been reported to have significantly lower apparent diffusion values than other tumors. Contrast agent uptake and wash-out levels of tumors can be detected with semi-quantitative perfusion MRI. For example, it is reported that almost all of the pleomorphic adenomas show an increasing enhancement time intensity curve and do not wash-out. On quantitative perfusion MRI studies using perfusion parameters such as Ktrans, Kep, and Ve, it is reported that WTs can show higher Kep and lower Ve values than other tumors. In this study, the contribution of advanced MRI to the diagnosis and differential diagnosis of SGTs will be reviewed.     

磁共振功能成像在肝细胞癌中的应用

近年来,肝细胞癌的发病率与死亡率在全球范围内逐年上升.随着分子影像学的发展,磁共振功能成像技术在各系统疾病中的应用越来越广泛,其在肝细胞癌诊断、鉴别诊断、术后疗效评估等方面发挥越来越重要的作用.作者就目前常用的几种功能磁共振成像技术在肝细胞癌中的应用现状进行综述.     

Advanced magnetic resonance imaging techniques in the evaluation of musculoskeletal tumors

Magnetic resonance (MR) imaging is an important modality for the preoperative and posttreatment evaluation of musculoskeletal tumors. In some cases, MR imaging is unable to offer information about the extension of tumoral necrosis and the presence of viable cells. Advanced MR imaging techniques are now used in association with conventional MR imaging to improve the diagnostic accuracy and the evaluation of treatment response. This article discusses each advanced MR imaging technique with regard to the clinical applications of tumor detection and characterization, differentiation of benign from malignant tumors and tumor tissue from nontumor tissue, and assessment of treatment response.     

功能MRI在瘙痒研究中的应用进展

瘙痒是一种令人不愉快的、引起搔抓冲动的感觉和情感体验。引起瘙痒的原因复杂多样,瘙痒的病理生理改变及发生机制尚不明确。功能MRI（fMRI）是一种基于MR成像发展起来的无创性活体成像技术,在皮肤科主要用于研究不同方式诱导瘙痒的机制,以及瘙痒为主要症状的几种皮肤病,如特应性皮炎、银屑病、慢性荨麻疹等。就fMRI在瘙痒、止痒机制中的研究以及在常见的瘙痒类疾病中的应用研究进展予以综述。     

Functional magnetic resonance imaging for neurosurgical planning in neurooncology

Functional magnetic resonance imaging (fMRI) is a non-invasive technique that is widely available and can be used to determine the spatial relationships between tumor tissue and eloquent brain areas. Within certain limits, this functional information can be applied in the field of neurosurgery as a pre-operative mapping tool to minimize damage to eloquent brain areas. In this article, we review the literature on the use of fMRI for neurosurgical planning. The issues addressed are: (1) stimulation paradigms, (2) the influence of tumors on the blood oxygenation level-dependent (BOLD) signal, (3) post-processing the fMRI time course, (4) integration of fMRI results into neuronavigation systems, (5) the accuracy of fMRI and (6) fMRI compared to intra-operative mapping (IOM).     

Functional magnetic resonance imaging of internet addiction in young adults

AIM: To report the results of functional magnetic resonance imaging (fMRI) studies pertaining internet addiction disorder (IAD) in young adults.METHODS: We conducted a systematic review on PubMed, focusing our attention on fMRI studies involving adult IAD patients, free from any comorbid psychiatric condition. The following search words were used, both alone and in combination: fMRI, internet addiction, internet dependence, functional neuroimaging. The search was conducted on April 20^th, 2015 and yielded 58 records. Inclusion criteria were the following: Articles written in English, patients’ age ≥ 18 years, patients affected by IAD, studies providing fMRI results during resting state or cognitive/emotional paradigms. Structural MRI studies, functional imaging techniques other than fMRI, studies involving adolescents, patients with comorbid psychiatric, neurological or medical conditions were excluded. By reading titles and abstracts, we excluded 30 records. By reading the full texts of the 28 remaining articles, we identified 18 papers meeting our inclusion criteria and therefore included in the qualitative synthesis.RESULTS: We found 18 studies fulfilling our inclusion criteria, 17 of them conducted in Asia, and including a total number of 666 tested subjects. The included studies reported data acquired during resting state or different paradigms, such as cue-reactivity, guessing or cognitive control tasks. The enrolled patients were usually males (95.4%) and very young (21-25 years). The most represented IAD subtype, reported in more than 85% of patients, was the internet gaming disorder, or videogame addiction. In the resting state studies, the more relevant abnormalities were localized in the superior temporal gyrus, limbic, medial frontal and parietal regions. When analyzing the task related fmri studies, we found that less than half of the papers reported behavioral differences between patients and normal controls, but all of them found significant differences in cortical and subcortical brain regions involved in cognitive control and reward processing: Orbitofrontal cortex, insula, anterior and posterior cingulate cortex, temporal and parietal regions, brain stem and caudate nucleus.CONCLUSION: IAD may seriously affect young adults’ brain functions. It needs to be studied more in depth to provide a clear diagnosis and an adequate treatment.     

Functional tumor imaging with dynamic contrast-enhanced magnetic resonance imaging

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is the acquisition of serial MRI images before, during, and after the administration of an MR contrast agent. Unlike conventional enhanced MRI, which simply provides a snapshot of enhancement at one point in time, DCE-MRI permits a fuller depiction of the wash-in and wash-out contrast kinetics within tumors, and thus provides insight into the nature of the bulk tissue properties. Such data is readily amenable to two-compartment pharmacokinetic modeling from which parameters based on the rates of exchange between the compartments can be generated. These parameters can be used to generate color-encoded images that aid in the visual assessment of tumors. DCE-MRI is used currently to characterize masses, stage tumors, and noninvasively monitor therapy. While DCE-MRI is in clinical use, there are also a number of limitations, including overlap between malignant and benign inflammatory tissue, failure to resolve microscopic disease, and the inconsistent predictive value of enhancement pattern with regard to clinical outcome. Current research focuses on improving understanding of the meaning of DCE-MRI at a molecular level, evaluating macromolecular and targeted contrast agents, and combining DCE-MRI with other physiologic imaging techniques such as positron emission tomography. Efforts to standardize DCE-MRI acquisition, analysis, and reporting methods will allow wider dissemination of this useful functional imaging technique.     

3.0T磁共振脑功能成像对额顶叶肿瘤神经微创手术的应用价值

目的探讨3.0T磁共振脑功能成像(fMRI)在额顶叶肿瘤神经微创手术前的应用价值。方法在3.0T磁共振上,49例额顶叶肿瘤病例术前行颅脑常规MRI平扫加增强和fMRI检查。依据fMRI成像后处理脑功能活动定位图(functional brain mapping,FBM)及常规MR扫描图像制定合理的手术计划,找出额顶叶肿瘤神经微创手术最佳路径切除肿瘤。结果 49例FBM图清晰的显示了大脑皮层左右两侧运动功能区的位置、大小和移位情况,为确定手术路径提供重要的参考依据。49例微创手术也取得比较满意的效果。结论 3.0TfMRI对额顶叶肿瘤神经微创手术的术前评价有重要临床意义,对手术切除脑功能区周围肿瘤并保留运动功能有重要的指导作用。     

Low field (0.02 T) magnetic resonance imaging of bone and soft tissue tumors

Extremely low field magnetic resonance imaging (MRI) was evaluated in 16 patients with bone and soft tissue tumors, both benign and malignant. Twelve of the lesions were located in the lower extremity, 2 in the gluteal and 2 in the shoulder region. The findings were compared to the results of computed tomography (CT). Low signal-to-noise ratio and poor spatial resolution result in an image quality which is inferior to that obtained with MR imaging at higher field strengths. In spite of this, the diagnostic information seems to be at least comparable to that obtained from CT.     

睾丸生殖细胞肿瘤的MRI诊断

目的：探讨睾丸生殖细胞肿瘤的 MRI 表现,提高对该疾病的 MRI 诊断水平。方法回顾性分析经手术病理证实的25例睾丸生殖细胞肿瘤患者临床及 MRI 资料,所有病例均行 MRI 平扫,其中16例行动态 MRI 增强扫描。利用 MRI 对睾丸肿瘤的大小、形态、信号特点、毗邻关系、强化方式及肿瘤血管情况进行评估,并与病理对照。结果25例睾丸生殖细胞肿瘤中,精原细胞瘤10例,其中 T2 WI 呈均匀低信号8例,稍低信号2例,增强扫描轻度结节样强化5例,明显均匀强化2例,其中4例可见纤维间隔强化;卵黄囊瘤4例,T1 WI 呈等低信号,T2 WI 呈稍高信号,增强扫描后肿瘤呈渐进式强化;成熟型畸胎瘤、表皮样囊肿、混合性生殖细胞肿瘤各3例,T1 WI 呈混杂低信号,T2 WI 呈混杂高信号;胚胎性癌2例,T1 WI 呈等低信号,T2 WI 呈混杂低信号,其内可见出血信号,增强扫描呈分隔强化。结论MRI 对睾丸生殖细胞肿瘤诊断正确率较高,对其病理分型、分期及鉴别诊断具有重要价值。     

Functional assessment of transplanted kidneys with magnetic resonance imaging

Kidney transplantation has emerged as the treatment of choice for many patients with end-stage renal disease, which is a significant cause of morbidity and mortality. Given the shortage of clinically available donor kidneys and the significant incidence of allograft dysfunction, a noninvasive and accurate assessment of the allograft renal function is critical for postoperative management. Prompt diagnosis of graft dysfunction facilitates clinical intervention of kidneys with salvageable function. New advances in magnetic resonance imaging (MRI) technology have enabled the calculation of various renal parameters that were previously not feasible to measure noninvasively. Diffusion-weighted imaging provides information on renal diffusion and perfusion simultaneously, with quantification by the apparent diffusion coefficient, the decrease of which reflects renal function impairment. Diffusion-tensor imaging accounts for the directionality of molecular motion and measures fractional anisotropy of the kidneys. Blood oxygen level-dependent MR evaluates intrarenal oxygen bioavailability, generating the parameter of R2* (reflecting the concentration of deoxyhemoglobin). A decrease in R2* could happen during acute rejection. MR nephro-urography/renography demonstrates structural data depicting urinary tract obstructions and functional data regarding the glomerular filtration and blood flow. MR angiography details the transplant vasculature and is particularly suitable for detecting vascular complications, with good correlation with digital subtraction angiography. Other functional MRI technologies, such as arterial spin labeling and MR spectroscopy, are showing additional promise. This review highlights MRI as a comprehensive modality to diagnose a variety of etiologies of graft dysfunction, including prerenal (e.g., renal vasculature), renal (intrinsic causes) and postrenal (e.g., obstruction of the collecting system) etiologies.     

Application of magnetic resonance imaging in cervical spondylotic myelopathy

Cervical spondylotic myelopathy (CSM) is the most common cause of spinal cord dysfunction and is caused by static or dynamic repeated compression of the spinal cord resulting from degenerative arthritis of the cervical spine and some biological injuries to the cervical spine. The T2 signal change on conventional magnetic resonance imaging (MRI) is most commonly associated with neurological deficits. Diffusion tensor imaging and MR spectroscopy show altered microstructure and biochemistry that reflect patient-specific pathogenesis and can be used to predict neurological outcome and response to intervention. Functional MRI can help to assess the neurological functional recovery after decompression surgery for CSM.     

MRI在脊髓型颈椎病中的研究进展

在脊髓型颈椎病(CSM) 的诊断中,常规MRI上脊髓的信号改变与神经功能障碍密切相关,扩散张量成像（DTI）和磁共振波谱（MRS）可以作为寻找神经功能损伤放射学标志物和了解脊髓生理学的工具,而功能MRI（fMRI）有助于评估CSM减压术后神经功能恢复情况。综述常见MRI技术在CSM病人诊断与治疗中的研究进展。     

Reproducibility and repeatability of quantitative sodium magnetic resonance imaging in vivo in articular cartilage at 3 T and 7 T

Osteoarthritis is a degenerative disease of articular cartilage that may be associated with a loss of glycosaminoglycans. Quantitative sodium magnetic resonance imaging is highly specific to glycosaminoglycan content and could be used to assess the biochemical degradation of cartilage in early osteoarthritis. However, the reproducibility and repeatability of this technique are not well documented. The aim of this study is to test the reproducibility and repeatability of sodium quantification in cartilage in vivo using intraday and interday acquisitions at 3 T and 7 T, with a radial 3D sequence, with and without fluid suppression. Fluid suppression was obtained by adiabatic inversion recovery (IR WURST) and is expected to improve the sensitivity of the method to glycosaminoglycan content. The root mean square of coefficients of variation are all in the range of 7.5-13.6%. No significant intermagnet, intersequence, intraday, and interday differences in the coefficients of variation were observed. Sodium quantification using IR WURST gave values closer to those reported in the literature for healthy cartilage (220-310 mM) than radial 3D. In conclusion, IR WURST was more accurate in context of sodium measurement, with a reproducibility and repeatability comparable to other compositional magnetic resonance imaging techniques of cartilage.     

Primary heart angiosarcoma detected by magnetic resonance imaging

We present a case of primary heart angiosarcoma in a 38-year-old male. The patient presented with severe dyspnoe and arrhythmia. Echocardiography showed multiple solid masses in the pericardium and pericardial effusion. Chest radiography revealed left-sided pleural effusion and suspicion of a mass projected on the right atrium. Non-enhanced chest computed tomography raised the suspicion of a pericardial neoplasm projected on the right atrium adjacent to ascending aorta with markedly thickened pericardium and multiple round-shaped masses around the heart. Cardiac-gated magnetic resonance imaging demonstrated an inhomogeneous mass in the free wall of the right atrium adjacent to ascending aorta and multiple pericardial masses. Biopsy performed through thoracoscopy confirmed the diagnosis of a primary heart angiosarcoma.     

Neural correlates of telling lies: a functional magnetic resonance imaging study at 4 Tesla

RATIONALE AND OBJECTIVE: Intentional deception (ie, lying) is a complex cognitive act, with important legal, moral, political, and economic implications. Prior studies have identified activation of discrete anterior frontal regions, such as the ventrolateral prefrontal cortex (VLPFC), dorsolateral prefrontal cortex (DLPFC), dorsal medial prefrontal cortex (DMPFC), and anterior cingulate cortex (ACC) during deception. To extend these findings, we used novel real-time functional magnetic resonance imaging (fMRI) technology to simulate a polygraph experience in order to evoke performance anxiety about generating lies, and sought to ascertain the neural correlates of deception. MATERIALS AND METHODS: In this investigational fMRI study done with a 4-T scanner, we examined the neural correlates of lying in 14 healthy adult volunteers while they performed a modified card version of the Guilty Knowledge Test (GKT), with the understanding that their brain activity was being monitored in real time by the investigators conducting the study. The volunteers were instructed to attempt to generate Lies that would not evoke changes in their brain activity, and were told that their performance and brain responses were being closely monitored. RESULTS: Subjects reported performance anxiety during the task. Deceptive responses were specifically associated with activation of the VLPFC, DLPFC, DMPFC, and superior temporal sulcus. DISCUSSION: These findings suggest the involvement of discrete regions of the frontal cortex during lying, and that the neural substrates responsible for cognitive control of behavior may also be engaged during deception.     

增强减影MRI诊断椎体转移瘤的研究

目的:探讨增强减影MRI对椎体转移瘤的诊断价值。方法:对30例41个椎体行常规MR平扫及增强扫描,并在增强后对病灶同一层面进行叠加减影处理。结果:增强减影MRI能清晰显示椎体内骨小梁结构,更容易发现微小病灶,更好地显示转移性肿瘤的形态学特点。结论:增强减影MRI技术对提高脊椎转移瘤的检出率有重要的临床应用价值。