BACKGROUND: Superparamagnetic iron oxide (SPIO) contrast agent has been extensively explore in tracing imaging following stem cell transplantation, arabinogalactan cell membrane receptor targeted imaging, as well as liposome-coated SPIO. OBJECTIVE: To summarize the research state of liposome-coated SPIO. METHODS: A computer-based online search of CNKI and Science Direct (1998-01/2009-09) was performed to search the articles about liposome-coated SPIO with key words "SPIO, superparamagnetic iron oxide, liposome, MR contrast agent" in Chinese and English. Articles related to MR contrast agent, and published in recently or authorial journals of the same field were included. A total of 48 articles were collected, and 24 articles and 1 composition related to liposome-coated SPIO were reviewed. RESULTS AND CONCLUSION: The incessant innovation in MR contrast agents can greatly improve the diagnosis of MRI. Due to the good performances, diagnostic value of SPIO in many diseases has surpassed previous MR contrast agents. Liposome-coated SPIO has the merits of low toxic side effect, and well targeting in specific tissues, thereby extensively being used in experimental studies and clinical application. With the development of functional imaging and molecular imaging, the use of liposome-coated SPIO must be more extensive.

Objective To investigate the value of superparamagnetic iron oxide particles(SPIO) in MR imaging for differentiation of metastatic lymph nodes from normal or reactively hyperplastic lymph nodes. Methods For the time course study,10 ?mol Fe of SPIO per extremity was administered to 6 animals, and images were obtained before and 1 h to 48 h after administration. Reactively hyperplastic lymph node model was established in 6 animals by injection of egg yolk emulsion, and tumor bearing lymph node model was established in another 6 rabbits. MR images of the popliteal lymph nodes were obtained before and 12 h after subcutaneous administration of SPIO. Imaging results were analyzed and correlated with pathological findings. Results In unenhanced images, the signal intensity of tumor free and metastatic lymph nodes did not differ significantly. After administration of SPIO, a significant signal intensity loss occurred in the tumor free lymph node, and the maximal loss occurred at 12 h, and the signal intensity reduced by 49%,28%,59%, and 89% on T 1WI, T 2WI, PDWI, and T  2WI, respectively at 48 h( P =0.000). However, the signal intensity of the metastatic lymph nodes remained unchanged. Conclusion MR imaging after subcutaneous administration of SPIO help to differentiate metastatic from normal or reactively hyperplastic lymph nodes.

BACKGROUND:Sensitivity of diagnoses differentiating smaller nodes of splenic metastasis (＜ 1 cm) from CT and MRI is poor. So whether superparamagnetic iron oxide can enhance magnetic resonance imaging (MRI) of splenic VX2 tumor in rats need to be further studied.OBJECTTVE: To establish splenic VX2 tumor models, investigate MRI scanning combining with superparamagnetic iron oxide of specific reticuloendothelial system, and study the diagnostic significance of superparamagnetic iron oxide-enhanced MR images on splenic metastases.DESIGN: Duplicated-measured animal study.SETTING: Medical Imaging Center, Nanfang Hospital of the Southern Medical University.MATERIALS: The experiment was carried out in the Medical Imaging Center (Military Key Laboratory), Nanfang Hospital of the Southern Medical University from May 2005 to March 2006. A total of 25 adult SD rats, of either gender, weighing 200-300 g, were selected in this study. The animal experiment had got confirmed consent from local ethic committee. All rats were randomly divided into tumor group (n =20) and blank control group (n =5).METHODS: Models of VX2 tumor in spleen were established successfully. The images obtained before and after administration of superparamagnetic iron oxide. T1-weighted image(T1WI) (450/12 ms) and T2-weighted image(T2WI)(4 000/128 ms) were used to scan sequences. The imaging parameters of various tissues were analyzed before and after superparamagnetic iron oxide-enhanced MRI scanning. Rats in the blank control group were not used to establish models and the sequences were scanned as the same as those in the experimental group.MAIN OUTCOME MEASURES: Signal characteristics of various tissues before and after before and after superparamagnetic iron oxide-enhanced MRI scanning.RESULTS: Eight out of 20 rats died in the tumor group and other 12 and 5 rats in the control group were involved in the final analysis. MR scanning indicated that 8 rats in the tumor group had splenic VX2 tumor. ① On plain MR scanning T1-weighted splenic VX2 tumor showed hypointensity or isointensity which approximated to the signal intensity (SI) of splenic parenchyma. All lesions had been not displayed well. ② On superparamagnetic iron oxide enhancement T2WI sequence the SI of splenic parachyma decreased obviously with percentage of signal intensity loss (PSIL) was 56.11%,But the SI of tumor was not evidently change with PSlL was 1.90%. Nevertheless the signal-to-noise ratio (SNR) of normal splenic parenchyma around the lesions had obviously difference (P ＜ 0.001) comparatively. So the contrast between tumor and spleen increased, and tumor displayed more clear. Moreover the contrast-to-noise (CNR) between VX2 tumor and splenic parenchyma had an evidently difference with before and after admininstration of superparamagnetic iron oxide (P ＜ 0.001 ).CONCLUSION: On superparamagnetic iron oxide enhancement T1WI sequence the contrast of tumor-to-spleen is poor.So it is not good to characterize the lesions in spleen. On superparamagnetic iron oxide enhanced T2WI the contrast degree of lesions increased obviously. Consequently, superparamagnetic iron oxide-enhanced T2WI MRI scanning can improve the rate of detection and characterization in lesions of spleen.

Objective To analyse and summarize the MRI characteristics of tumor‐like inflammatory demyelinating diseases (TIDD) .Methods MRI findings of 10 cases with pathologically proved TIDD were analyzed retrospectively ,all patients received plain and enhanced MRI scan .Results 3 cases showed multiple lesions in bilateral frontal and parietal lobes ,and 7 cases showed soli‐tary mass ,in which 2 lesions located in the occipital lobe ,2 in the basal ganglia ,2 in the second to fifth segment of cervical cord ,and 1 lesion located in the left frontal parietal lobe .The shape of 7 lesions were irregular ,2 were stripped ,while 1 lesion was oval .6 cases had clear boundary ,while 4 showed ambiguous .Solitary lesions were 1 .7 cm -5 .6 cm in diameter(mean 4 .0 cm ± 1 .48 cm) .8 cases manifested mild edema while 2 had no edema .On MRI plain scan ,lesions were hypointensity on T1WI and hyperintensity on T2WI in 8 cases ,isointensity on T1 WI and hyperintensity on T2 WI in 2 cases ,and all lesions were hyperintensity on FLAIR sequence .DWI were performed in 3 cases ,all lesions showed hyperintensity ,2 of them had patchy hypointensity signal .Hemorrhage was detected in 3 lesions ,cystic lesions or calcification were not found in all cases .On post‐contrast scan ,3 lesions showed ring like enhancement ,2 showed obviously heterogeneous enhancement ,2 had mild enhancement and 2 cases had no enhancement ,1 presented with open ring like enhancement .Conclusion TIDD shows some specific MRI features ,and MRI is helpful to the diagnosis of TIDD .

Objective To investigate MR findings and analyze the misdiagnosed cases of pituitary macroadenoma.Methods MR features of 1 90 patients of pituitary macroadenoma confirmed by operation and pathology were reviewed.Results 1 6 cases were mis-diagnosed as craniopharyngioma,chordoma,or meningioma.Among the sixteen cases,eight cases with cyst degeneration and hemor-rhage were misdiagnosed as craniopharyngioma;five cases with clival and sphenoid sinus destruction were misdiagnosed as chordo-mas;three cases with suprasellar and anterior cranial fossa extension were misdiagnosed as meningiomas.Conclusion Craniophar-yngioma,chordoma and meningioma should be considered in the differential diagnosis of atypical pituitary macroadenoma.The com-prehensive analysis should be based on a variety of signs.

Objective To study CT features of thymoma,so that to improve the accuracy of CT diagnosis and differential diagnosis.Methods 31 cases of thymomas proved by surgery and pathology were examined with conventional CT scans.CT findings of thymoma were analyzed.Results The lesions in 27 cases(87.1%)were located in the anterior upper and middle mediastinum.There were benign lesion in 11,including mass-cardiovascular interface(MCI) with convex type(8 cases),flatness type(1 cases) and concave type(2 cases).20 cases were malignant lesion,including MCI with cast type(18 cases) and concave type(2 cases).Irregular invasion to adjacent organs was found in 11 cases,others included pericardiac effusion(n=6),pericardial and mediastinal invasion(n=2),pleural effusion(n=4),pneumonia(n=2),lung,bone,mediastinal lymphadens metastasis(n=2) and liver,pancreas metastasis(n=1).Conclusion CT scans is of significant value in diagnosis and differential diagnosis of thymoma.

BACKGROUND: The imaging technique of CT and MRI has lower diagnostic accuracy in analyzing lymph node location due to the nonspecific diagnostic criteria. However, this situation can be improved with Gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA), especially the use of lymphatic targeting contrast agent. OBJECTIVE: To prepare DTPA-coupled human serum albumin (HSA) labeled with gadoliniumion, and to investigate the enhancement for the lymph node in animal experiment, in further, to explore the potential value of its application. DESIGN, TIME AND SETTING: The randomized grouping, controlled animal experiment was performed at the laboratory of Medical Imaging Center, Nanfang Hospital from December 2008 to April 2009. MATERIALS: GdCI3 was prepared with Gd2O3 reacted with 0.1mol/L HCI for 10 minutes. Then, DTPA cyclic anhydride and HAS solution were mixed together at the ratio of 200:1 or 100:1. The product was divided into 4 equal portions, which was reacted with 5.0, 6.0, 7.0, 8.0 pH values at room temperature for 30 minutes. At last, GdCI3 was added. The complexation reaction was completed within 1 minute. The Gd-DTPA-HAS was dried and prepared for Gd-DTPA-HAS solution with concentration of 0.50 mmol Gd/L.METHODS: Six New Zealand rabbits were undergone the MRI examination, followed by subcutaneous injection of 0.2 mL with Gd 0.50 mmol/L HSA-Gd-DTPA solution. And contrast scanning was performed at minutes 30, 60 and 180 after injection. The signal intensity of popliteal lymph node was measured and the enhancement rate was obtained. MAIN OUTCOME MEASURES: The number of combined Gd-DTPA per HSA at different reaction conditions was measured, and coupling efficiency of HSA-DTPA was calculated. The enhancement rates of lymph node, as well as dynamic changes were observed. RESULTS: ①The number and coupling efficiency of HSA-coupled of gadolinium ions were increased with the pH value of the reaction system at the same DTPA-to-HSA molar ratio. ②At the same pH value of the reaction system, the number of HSA-coupled of gadolinium ions increased with the DTPA-to-HSA molar ratios while the coupling efficiency of HSA-coupled of gadolinium ions decreased.③After subcutaneous injection, HSA-Gd-DTPA entered the lymphatic vessel, which resulted in obvious homogeneous enhancement of the lymphatic vessels and popliteal lymph nodes. CONCLUSION: The number and coupling efficiency of HSA-coupled of gadolinium ions can be increased in pH=8.0, 0.1 mol/L NaHCO_3 reaction system. HSA-Gd-DTPA is an effective contrast agent targeted for lymph node after subcutaneous administration.

Objective To explore the value of pretargeting technology in vitro MRI of L5 peptide guided streptavidin-conjugated and polyethylene glycol modification protected ultra-small superparamagnetic iron oxide(SA-PEG-USPIO) to hepatocellular carcinoma(HCC) via glypican-3(GPC3) receptor.Methods Direct immumofluorescence assay with carboxyfluorescein(FAM) labeled L5 and competitive inhibition was performed in HepG2 and HL-7702 cells.Imaging was obtained from fluorescent microscope.Immunoassay fluorescence images were carried out to determine the expression of GPC3 in HepG2 cell.PEG-USPIO conjugated with streptavidin was made by carbodiimide reaction,and the hydrodynamic diameters,Zeta potential and magnetic relaxivity of SA-PEG-USPIO and PEG-USPIO were measured.HL7702 cells were used for evaluate cells viability of SA-PEG-USPIO and PEG-USPIO.HepG2 and HL-7702 cells were used as experimental and control group respectively.Each of the two cell lines were further divided into three groups:L5-BT united SA-PEG-USPIO group,SA-PEG-USPIO group and control group.Prussian blue staining and MRI was preformed to observe the targeting efficacy of SA-PEG-USPIO respectively,and normalized T2 signal was recorded.The significant changes of normalized T2 signal intensity among groups was deterumine by using One-way analysis of variance.Results There were much more fluorescences on the membrane and cytoplasm of HepG2 cells than those on HL-7702 cells and cells of competition group.And indirect immunofluorescence images show the obvious expression of GPC3 in HepG2 cell.The SA-PEG-USPIO and PEG-USPIO nanoparticles had hydrodynamic diameters of (22.73 ± 3.31) and (35.97±5.19)nm,Zeta potential of them were (4.22±0.53) and (-7.91± 1.22)mV and magnetic relaxivity were 0.139 4× 103 and 0.103 9 × 103 mM-1s1.Although the highest concentration of SA-PEG-USPIO and PEG-USPIO was 2.4 mmol/L,cells viability was greater than 80％.The most iron particle was observed in L5-BT united SA-PEG-USPIO group of HepG2 cells.In vitro MR,the normalized T2 signal intensity of HepG2 cells in L5-BT united SA-PEG-USPIO group,SA-PEG-USPIO group and control group were 39±7,77 ± 12 and 93 ± 4.There was significant difference among those three groups (F=23.96,P＜0.01).The normalized T2 signal intensity of HL-7702 cells in each of three groups were 69± 11,78±8 and 95±5.There was no significant difference among those three groups (F=2.86,P＞0.05).Conclusion By the pretargeting method,L5 peptide guided SA-PEG-USPIO has effective targeting ability to HepG2 cells in vitro.

Objective: To analyze the essential medicines supply of medical institutions at county-level in Shaanxi Province and to provide empirical evidences and suggestions to improve relevant policies. Methods:A strati-fied cluster random sampling method was used to choose the institution samples. A survey was conducted to study the supply of essential medicines in 2012. Indicators include the variety and amount of essential medicines procured, the medicine shortage condition, and the rate of winning the bid for essential medicine. Results:Essential medicines ac-counted for 69 . 1% of all medicines;and procurement of essential medicines accounted for 42 . 4% of all procurement spending on medicines. Of the top 25 chemical products of essential medicines, provincial supplementary medicines accounted for 33. 9%;and among the top 25 traditional Chinese medicines of essential medicines, the provincial sup-plementary medicines accounted for 51. 9%. All 27 medical institutions faced a shortage of medicines. There were 47 kinds of essential drugs in urgent need were out of bid. Conclusion:Essential medicine supply of medical institutions at county-level is in good condition;however, more attention needs to be paid to medicine shortage. We should take measurements to standardize the process of bidding for essential medicines and strengthen the management of medi-cine shortage in order to better meet patients’ needs.

Objective To illustrate the CT,MRI and PET-CT features of spinal osteoblastoma,and provide an important reference for the preoperative diagnosis and assessment.Methods The imaging and clinical data in 16 cases of spinal osteoblastoma confirmed by surgery and pathology were analyzed retrospectively.Results Age of onset in 11 cases ranged from 10 to 29 years old,5 cases from 30 to 51 years old.Tumors were originated from the spine appendage in 13 cases,and from the vertebral bodies in 3 cases.Tumors presented as expansive bone destruction in 6 cases,and as osteolytic bone destruction in 10 cases.13 cases were diagnosed as benign diseases and 3 cases as invasive ones.Calcification or ossification was seen in all cases,with sclerotic margin of variable thickness and peripheral patchy high density of bone sclerosis.The soft tissue mass was found in 15 cases and intraspinal involvement was showed in 13 cases.The tumors showed isointensity or hypointensity on T 1WI,isointensity or hyper-intensity on T2WI in 13 cases,and showed heterogenous enhancement after contrast administration in 13 cases.PET-CT depicted the nodular or lobulated distribution of radioactive tracer with high radioactive concentration,with increment in standardized uptake value in 5 cases.Conclusion The typical imaging signs of spinal osteoblastoma were expansile,osteolytic bone destruction of the spine appendage,accompanying the soft tissue mass,with a speckled or nodular pattern of calcification or ossification within the lesions.Inhomogeneous signal intensity and inhomogeneous enhancement on MRI and nodular or lobulated high radioactive concentration for the tumors on PET-CT are found.