Myocardial fibrosis detection in arrhythmogenic right ventricular dysplasia/cardiomyopathy by 3. 0T magnetic resonance imaging

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is characterized by fibro-fatty replacement of the right ventricle.However,the feasibility and significance of myocardial fibrosis detec-ted by delayed enhancement (DE) using 3.0T magnetic resonance imaging (MRI) in.ARVD /C is seldomly studied.Methods Twenty-seven consecutive patients were prospectively evaluated for ARVD /C.Magnetic reso-nance imaging was performed on a 3.0T scanner.Ten minutes after intravenous administration of 0.2 mmol /kg of gadodiamide,DE-MRI was obtained.Diagnosis of ARVD /C was based upon the Task Force criteria and in-cluded MRI findings.Results Seventeen(59% ) of 27 patients met the Task Force criteria for ARVD /C.Right ven-tricle DE was found in all (100% ) ARVD /C patients compared with none (0%) of the 10 patients without ARVD /C (P <0.001) .Additional left ventricular DE was found in 8/17 ARVD/C patients while without left ventricular mor-phological and functional abnormalities detected by echocardiography or MRI.Conclusions DE using 3.0T MRI could effectively detect myocardial fibrosis in the right and left ventricular myocardium in ARVD /C patients.Detection of myocardial fibrosis may have an important clinical significance in ARVD/C diagnosis.Histological left ventricle in-volvement may be easily missed by echocardiography.

Feasibility of imaging superficial palmar arch using microultrasound,7T and 3T magnetic resonance imaging

AIM To demonstrate feasibility of vessel wall imaging of the superficial palmar arch using high frequency microultrasound, 7T and 3T magnetic resonance imaging(MRI).METHODS Four subjects(ages 22-50 years) were scanned on a micro-ultrasound system with a 45-MHz transducer(Vevo 2100, Visual Sonics). Subjects' hands were then imaged on a 3T clinical MR scanner(Siemens Biograph MMR) using an 8-channel special purpose phased array carotid coil. Lastly, subjects' hands were imaged on a 7T clinical MR scanner(Siemens Magnetom 7T Whole Body Scanner) using a custom built 8-channel transmit receive carotid coil. All three imaging modalities were subjectively analyzed for image quality and visualization of the vessel wall. RESULTS Results of this very preliminary study indicated that vessel wall imaging of the superficial palmar arch was feasible with a whole body 7T and 3T MRI in comparison with micro-ultrasound. Subjective analysis of image quality(1-5 scale, 1: poorest, 5: best) from B mode, ultrasound, 3T SPACE MRI and 7T SPACE MRI indicated that the image quality obtained at 7T was superior to both 3T MRI and micro-ultrasound. The 3D SPACE sequence at both 7T and 3T MRI with isotropic voxels allowed for multi-planarreformatting of images and allowed for less operator dependent results as compared to high frequency microultrasound imaging. Although quantitative analysis revealed that there was no significant difference between the three methods, the 7T Tesla trended to have better visibility of the vessel and its wall. CONCLUSION Imaging of smaller arteries at the 7T is feasible for evaluating atherosclerosis burden and may be of clinical relevance in multiple diseases.

3T磁共振血管成像对糖尿病下肢大血管病变的诊断价值

目的评价3T磁共振血管成像(3.0-Telsa magnetic resonance angiography,3T MRA)对糖尿病患者下肢动脉病变(peripheral artery disease,PAD)的诊断价值。方法根据大血管彩超结果,对下肢血管狭窄>50%的46例2型糖尿病患者做3T MRA检查,并用数字减影血管造影(digital subtraction angiography,DSA)作为对照,评价其对髂总、股、小腿和足动脉等4段血管病变诊断的意义。结果3T MRA能完整显示整个下肢PAD,对踝以上动脉血管病变显像清晰,且病变分布广泛、远端重于近端、呈多节段性狭阻。3T MRA显示的股动脉、小腿动脉的狭窄>50%病变节段数与DSA无明显差异(P=0.965,P=0.846),但其诊断的足部动脉狭阻节段数明显多于DSA(P=0.006).3T MRA诊断狭窄>50%的动脉病变的敏感度和特异度分别为:股动脉皆为100%,小腿动脉为95.62%和100%,足动脉为100%和72.22%。两种方法诊断不同节段动脉病变的κ值依次为:股动脉1.000(P<0.001),小腿动脉0.949(P<0.001),足部动脉0.635(P<0.05)。结论3T MRA可清楚显示糖尿病患者踝以上的动脉病变,对股及小腿动脉病变的诊断价值与DSA类似,但对足部动脉可能有夸大效应。

3 T MRI关节软骨生化成分成像的研究进展

近年来,3 T MRI技术发展十分迅速,已广泛应用于软骨病变的诊断和疗效评价。各种软骨成像序列不断被开发和应用,目前已从传统的二维、三维形态成像向生化成分成像转变,以期能够对关节软骨形态学改变之前的软骨生化改变进行显示,为早期软骨损伤诊断和监测提供临床参考依据。目前,关节软骨生化成分成像技术包括T2mapping、T2*mapping及T1ρ成像等。就3 T MR关节软骨生化成分成像的临床应用及研究进展予以综述。

Better prognostic determination of cT3 rectal cancer through measurement of distance to mesorectal fascia:A multicenter study

Objective:To forward the magnetic resonance imaging(MRI)based distance between the deepest tumor invasion and mesorectal fascia(DMRF),and to explore its prognosis differentiation value in cT3 stage rectal cancer with comparison of cT3 substage.Methods:This was a retrospective,multicenter cohort study including cT3 rectal cancer patients undergoing neoadjuvant chemoradiotherapy followed by radical surgery from January 2013 to September 2014.DMRF and cT3 substage were evaluated from baseline MRI.The cutoff of DMRF was determined by disease progression.Multivariate cox regression was used to test the prognostic values of baseline variables.Results:A total of 804 patients were included,of which 226(28.1%)developed progression.A DMRF cutoff of7 mm was chosen.DMRF category,the clock position of the deepest position of tumor invasion(CDTI)and extramural venous invasion(EMVI)were independent predictors for disease progression,and hazard ratios(HRs)were 0.26[95%confidence interval(95%CI),0.13-0.56],1.88(95%CI,1.33-2.65)and 1.57(95%CI,1.13-2.18),respectively.cT3 substage was not a predictor for disease progression.Conclusions:The measurement of DMRF value on baseline MRI can better distinguish cT3 rectal cancer prognosis rather than cT3 substage,and was recommended in clinical evaluation.

Found Different Attitude Fracture Characteristics of the NMR Curve by Application of 3D Printing Samples

Nuclear magnetic resonance (NMR) has many advantages, such as little testing time, no harm to rock specimen, and is widely used in the measurement of reservoir pore structure. 3D printing also has many advantages, such as repeating the printing the same attributes samples, forming sample by known rock pore structure, adding different pores or fractures to sample. For the study of fractured reservoir provides a new train of thought by combining NMR and 3D printing. Nuclear magnetic core analysis is an important work in the study of core, using a T2 spectrum at a certain echo time can also be found in the core fractures. The study, by CT scans to establish reservoir pore structure, based on the basic of adding different attitude fracture forming four fracture characteristics of rock sample, using 3D printing for solid sample, through the analysis of the nuclear magnetic resonance (NMR) of these sample, get the response characteristics of fracture characteristics on the T2 curve, the quantitative calculation of fracture porosity of rock sample, the result accord with to establish the model of fracture porosity is very good. For the study of fractured oil and gas reservoir development the new field.

CXCR4 Peptide Conjugated Au-Fe2O3 Nanoparticles for Tumor-targeting Magnetic Resonance Imaging

Peptide-functionalized Au-Fe2O3 nanoparticles（termed as anti-CXCR4-Au-Fe2O3 NPs） have been constructed through conjugation of dumbbell-like Au-Fe203 NPs with C-X-C motif chemokine receptor 4（CXCR4） binding cyclic peptide. One dumbbelMike Au-Fe2O3NP composes an Au NP[（3.3±0.3） nm in diameter] for conjugating CXCR4 binding cyclic peptide through Au-S covalent bond and a Fe2O3 NP[（8.7±0.8） nm in diameter] for using as T2-weighted magnetic resonance imaging（MRI） contrast agent. The anti-CXCR4-Au-Fe2O3 NPs have reasonable biocompatibility and integration of T2-weighted MRI contrast and tumor-targeting functionalities. The anti- CXCR4-Au-Fe2O3 NPs exhibit strong interactions with two kinds of breast tumor cells, MCF-7 cells and MDA-MB-231 cells, and high negative contrast in MRI of MDA-MB-231 tumor bearing mouse with 62% decreasing of MRI signal, indicating that the anti-CXCR4-Au-Fe2O3 NPs can recognize tumor with high efficacy and specificity.

Exfoliated FePS nanosheets for T-weighted magnetic resonance imaging-guided near-infrared photothermal therapy in vivo

Developing bifunctional nanoplatforms integrating advanced biological imaging with high-performance therapeutic functions is interesting for nanoscience and biomedicine.Herein,thin-layered FePS3 nanosheets modified with amine polyethylene glycol(FePS3-PEG)are synthesized by ultrasonicated exfoliation of bulk Fe PS3 single crystals under Ar atmosphere and in situ chemical functionalization with amine PEG.The prepared Fe PS3-PEG nanosheets give a photothermal conversion efficiency of 22.1%under 808-nm laser and evident T1relaxation(r1=2.69(mmol L^(-1))^(-1)S^(-1))in external magnetic fields.Biologically experimental results in vitro and in vivo demonstrate that Fe PS3-PEG nanosheets have good biocompatibility and exhibit excellent photothermal therapy(PTT)effect under clear T1-weighted magnetic resonance imaging(MRI).The characteristics of Fe PS3-PEGnanosheets enable them to be a promising nanomedicine for T1-weighted MRI-guided near-infrared PTT of cancers.

Impact of Field Strength and Respiratory Motion Control on Diffusion-Weighted MR Imaging of the Liver

Purpose: To evaluate the impact of field strength and respiratory motion control on diffusion-weighted MR imaging (DWI) of the liver at 1.5 and 3 T. Material and Methods: Three DWI sequences using seven b-values from 20 - 400 s/mm2 were designed with identical parameters but with different handling of respiratory motion [respiratory triggered (RT), free breathing (FB), breath hold (BH)] on 3 T and 1.5 T. Thirteen volunteers were examined at a 3 T and six of them also at a 1.5 T magnet. DW images were analyzed quantitatively and qualitatively. Regions of interest were placed in cranial, middle and caudal parts of the right liver lobe (RLL) and ADC and SNR were calculated. Results: ADC in RLL tended to be lower at 3 T MRI. Least inter-subject ADC variability was found with RT in the middle RLL at 3 T. Highest ADCs were found caudally in the RLL. Significant differences in ADC between middle and caudal RLL were calculated in FB and RT at 3 T and FB and BH at 1.5 T, respectively. No significant difference in SNR was found between 3 T and 1.5 T. There were significantly more artifacts in the left liver lobe (LLL) compared to the RLL in all sequences and in the LLL at 3 T compared to 1.5 T. Conclusion: Our study suggests that longitudinal hepatic ADC measurements should be performed using equivalent field strength, b-values, and acquisition technique, given influence of these factors on ADC measurements.