2013年ISMRM年会前列腺MRI研究进展

第21届国际医学磁共振学会(ISMRM2013)在美国犹他州盐湖城举行,此次会议共收录与前列腺相关的论文91篇,这些论文主要关注磁共振功能成像技术,如扩散加权成像(DWI)、磁共振波谱成像(MRS)、标记靶分子成像和动态增强图像(DCE)等在前列腺癌诊断、鉴别诊断中的应用。本文对以上的研究现状进行综述,旨在提高我国对前列腺磁共振成像研究的新认识。

Pancreatitis in patients with pancreas divisum:Imaging features at MRI and MRCP

AIM:To determine the magnetic resonance cholangiopancreatography(MRCP)and magnetic resonance imaging(MRI)features of pancreatitis with pancreas divisum(PD)and the differences vs pancreatitis without divisum.METHODS:Institutional review board approval was obtained and the informed consent requirement was waived for this HIPAA-compliant study.During one year period,1439 consecutive patients underwent successful MRCP without injection of secretin and abdominal MRI studies for a variety of clinical indications using a 1.5 T magnetic resonance scanner.Two experienced radiologists retrospectively reviewed all the studies in consensus.Disputes were resolved via consultation with a third experienced radiologist.The assessment included presence and the imaging findings of PD,pancreatitis,and distribution of abnormalities.The pancreatitis with divisum constituted the study group while the pancreatitis without divisum served as the control group.MRCP and MRI findings were correlated with final diagnosis.Fisher exact tests and Pearson × 2 tests were performed.RESULTS:Pancreatitis was demonstrated at MRCP and MRI in 173 cases(38 cases with and 135 cases without divisum)among the 1439 consecutive cases.The recurrent acute pancreatitis accounted for 55.26%(21 of 38)in pancreatitis patients associated with PD,which was higher than 6.67%(9 of 135)in the control group,whereas the chronic pancreatitis was a dominant type in the control group(85.19%,115 of 135)when compared to the study group(42.11%,16 of 38)(χ 2 = 40.494,P < 0.0001).In cases of pancreatitis with PD,the dorsal pancreatitis accounted for a much higher percentage than that in pancreatitis without PD(17 of 38,44.74% vs 30 of 135,22.22%)(χ 2 = 7.257,P < 0.05).CONCLUSION:MRCP and MRI can depict the features of pancreatitis associated with divisum.Recurrent acute pancreatitis and isolated dorsal involvement are more common in patients with divisum.

Fluorination over Cr doped layered perovskite Sr_(2)TiO_(4) for efficient photocatalytic hydrogen production under visible light illumination

Cr doped Ruddlesden-Popper compound Sr2 TiO4 has been successfully modified by fluorine to form a new compound Sr2 Ti(0.95) Cr(0.05) O3 F2. Structure analysis suggests two types of fluorine in the structure of this new compound, i.e. intralayer and interlayer F, which induce strong built-in electric field within this layered compound. The electric field stems from uneven distribution of F atoms on the two sides of perovskite layers therefore leads to charge disproportionation. DFT calculations suggest that this unique structural feature is highly beneficial for charge dissociations as it breaks the coplanar settlement of conduction band minimum and valence band maximum whilst maintains the 2 D charge transportation properties. This is clearly demonstrated by the superior photocatalytic activities of Sr2 Ti(0.95) Cr(0.05) O3 F2 for hydrogen production from water. Apparent quantum efficiency(AQE) as high as 1.16% at 420 ± 20 nm has been achieved which stands as the highest AQE reported on Sr2 TiO4 to date. Photoelectrochemical(PEC)analysis confirms improved charge separation conditions and prolonged charge lifetime.

Boosting visible-light-driven water splitting over LaTaON_(2) via Al doping

LaTaON_(2)is an attractive visible-light-active photocatalyst for water splitting due to its broad visible light absorption as far as 650 nm and proper band edge positions.Notwithstanding these promising properties,LaTaON_(2)generally exhibits poor photocatalytic activity because of its high defect concentration that severely hinders charge separation.Here,LaTaON_(2)has been modified by doping Al into the Ta sublattice,i.e.,LaTa_(1−x)Al_(x)O_(1+y)N_(2−y)(0≤x≤0.20).Al doping not only inhibits the defect concentration and increases surface hydrophilicity but also maintains the desired visible light absorption of LaTaON_(2).These important modifications substantially ameliorate the charge separation conditions within LaTaON_(2)and are responsible for a much enhanced photocatalytic performance for water redox reactions under visible light illumination.Under optimal conditions,the Al-doped LaTaON_(2)delivers an apparent quantum efficiency of 1.17%at 420±20 nm for water oxidation into O_(2),outperforming most LaTaON_(2)-based photocatalysts.These findings highlight Al as a useful dopant to open up the photocatalytic potential of metal oxynitrides whose activity is often undermined by a high defect concentration.

Expediting H_(2)Evolution over MAPbI_(3)with a Nonnoble Metal Cocatalyst Mo_(2)C under Visible Light

Halide perovskites have been emerging as promising photocatalytic materials for H_(2)evolution from water due to their outstanding photoelectric properties.However,the lack of proper surface reactive sites greatly hinders the photocatalytic potential of these fascinating compounds.Here,Mo_(2)C nanoparticles have been anchored onto methylammonium lead iodide(MAPbI_(3))as a nonnoble metal cocatalyst to promote H_(2)evolution reactions.The Mo_(2)C nanoparticles have opposite zeta potential with MAPbI_(3)thereby electrostatically assembled onto the MAPbI_(3)surface,i.e.,Mo_(2)C@MAPbI_(3).Our results show that the anchored Mo_(2)C nanoparticles have a strong interplay with MAPbI_(3)substrate so that photogenerated electrons of MAPbI_(3)can be rapidly separated and transferred into Mo_(2)C for further H_(2)evolution reactions.Under optimal conditions,Mo_(2)C@MAPbI_(3)delivers exceptionally high photocatalytic performance for visible light-driven H_(2)evolution that clearly outperforms pristine MAPbI_(3)and Pt-deposited MAPbI_(3).An apparent quantum efficiency as high as 12.65%at 600±40 nm has been attained for H_(2)evolution,surpassing most of the MAPbI_(3)-based photocatalyst reported.These results signify the usefulness and applicability of Mo_(2)C as a new nonnoble metal-based cocatalyst in solar water splitting.