Combined MR Imaging for Pulmonary Embolism and Deep Venous Thrombosis by Contrast-enhanced MR Volume Interpolated Body Examination

MR pulmonary angiography(MRPA)combined with indirect MR venography(MRV)was attempted by using 3D contrast-enhanced MR volume interpolated body examination(VIBE)sequence.Agreement rate for deep venous thrombosis(DVT)detection between MRV and duplex sonography(DUS)was evaluated;the potential of this method for venous thromoembolism(VTE)was also investigated.Thirty-four patients with DUS-identified DVT were enrolled in this study.MRI was performed after a single administration of Gadopentetate dimeglumine.Fatsuppressed 3D VIBE was applied for visualizing pulmonary arteries,abdominal veins,pelvic and leg veins,ranging from lung apex to ankle level.Two radiologists observed the MR images in consensus,recorded the location and number of emboli.MRV images were assessed based on per-vein segment.The agreement rate between MRV and DUS for venous segment-to-segment comparison was analyzed by Wilcoxon rank sum test.All the patients were diagnosed as having DV 1 by MRV.MRV detected 55 more venous segments with thrombi than DUS based on per-vein segment analysis.Twenty-three patients with pulmonary embolism(PE)were detected by MRPA.Twenty-one patients underwent both pulmonary CT angiography and MRPA,and consistency for PE detection was 100%.Total examination time of the combined MR protocol was 7 min for each patient.The contrast-enhanced VIBE sequence proves to be a feasible and reliable method for VTE diagnosis in one-stop MR scanning procedure,and contrast-enhanced VIBE performs better to depict DVT than DUS on per-vein segment basis.

Plasmon-tunable Au@Ag core-shell spiky nanoparticles for surfaceenhanced Raman scattering

A facile synthetic approach has been developed to prepare uniform and size-tunable spiky Au@Ag core-shell nan oparticles (NPs) to tailor the localized surface plasm on res onance (LSPR) properties. The gradual assembly of small Au nano crystals allows the size of spiky Au NPs to be modulated from tens to several hundreds of nano meters by tuning the concentration of initial Au seeds and Au source;and the thick ness of the Ag shell can be adjusted with stepwise reduction of Ag(l)ions. The LSPR bands of such spiky Au@Ag core-shell NPs resemble those of pure spiky Au NP cores of similar sizes in near-infrared region, and increasing the Ag shell thickness results in a blue shift and broadening of the LSPR band in the n ear-i nfrared regi on. Additi on ally, the spiky Au@Ag core-shell NPs exhibit improved surface-e nhan ced Rama n scattering (SERS) activity as compared to the bare spiky Au NPs and spherical Ag@Au NPs. This work has offered a facile route to synthesize plasmonic metal NPs with LSPR band in 650 to 800 nm that show strong enhancement of localized electromagnetic field, which provides an effective SERS substrate for SERS imaging and detection in biological fluids and tissues.