BACKGROUND: As magnetic resonance (MR) contrast, a large number of clinical and experimental researches have been done on superparamagnetic iron oxide (SPIO), while the report on the labeled cell passaged cells is rare.OBJECTIVE: MR imaging was performed to the labeled bone mesenchymal stem cells (BMSCs) and its passaged cells in vitro, in order to establish the base of monitoring magnetic labeled BMSCs with magnetic resonance imaging (MRI) in vivo.DESIGN, TIME AND SETTING: The cytological in vitro experiment was performed at the Imaging Research Institute and Institute of Rheumatology and Immunology of North Sichuan Medical College Hospital from June 2006 to January 2007. MATERIALS: Two clean female albino rats (Animal Center, North Sichuan Medical College), SPIO (Schering AG,Germany) were used in this study.METHODES: Bilateral femur and tibia bone marrow was extracted from rats. BMSCs were harvested and purified using the adherent method, and then labeled with 600 μL ferric oxide-polylysine compound (42 mg/L iron concentration) in vitro. MAIN OUTCOME MEASURES: Cell maker-positive rate and the MR signal intensity were respectively measured to the labeled cells and its passaged cells under the inverted microscope and magnetic resonance imaging. RESULTS: Following Prussian blue staining, labeling rate of SPIO labeled cells at the first passage was 100%. With increased passage, the labeling rate was reduced from the first to fifth passages. Compared with non-labeled PBS control, there was no significant difference in signal intensity in the first and second passages cells, but the signal intensity percentage was gradually decreased with signal intensity of increased cell passage from the third passage. Cell labeling rate was negatively correlated with T2~*WI signal intensity (r=-0.986 6, P <0.005). CONCLUSION: The iron particles in the magnetic labeled cells can be passaged to the offspring cells, and can be monitored in a certain period of time with MRI in vitro. These results firstly introduced that SPIO-labeled cell iron particles can decrease with cell passage.

Objective To characterize pancreatic perfusion in swines with experimental chronic pancreatitis(CP)by dynamic contrast-enhanced MRI and to correlate it with the severity of CP.Methods Twenty-two swines were randomly selected and made CP by ligation of main pancreatic duct.Six healthy swines served as control.MR perfusion study with dynamic contrast-enhanced MRl was carried out on the swines under anesthesia.The animals were euthanized after MR perfusion exam.The swines were divided into 4 groups according to the histological results of pancreas:normal group,group of CP of grade 1,group of CP of grade 2,and group of CP of grade 3.The maximum perfusion slope rate,the time-to-peak value and the maximum enhancement rate was compared between the groups using variance analysis,and the relationship between each perfusion parameters and severity of CP was made by correlative analysis.Results Twenty-one swines underwent MR perfusion study,including 7 swines in normal group,7 in group of grade 1 CP,3 in group of grade 2 CP,and 4 in group of grade 3 CP.On signal intensity time curve(SI-T)derived from MR perfusion weighted imaging,the m~imum slope rate was(10.88±1.20)%,(10.59±1.02)%,(6.67±1.31)%,and(5.48±1.97)%for normal swines,swines with grade 1 CP,swines with grade 2 CP and swines with grade 3 CP,respectively(F=20.51,P＜0.05).The time-to-peak value was(13.82±3.09)s,(12.31±5.52)s,(20.55±3.79)s and(37.26±14.56)s respectively(F=10.68,P＜0.05).The maximal signal enhancement rate was(62.95±20.20)%,(60.44±20.00)%,(46.33±22.70)%,and(67.65±32.66)%,respectively(F=0.53,P＞0.05).The highest slope value(r=-0.72,P＜0.05)and the time-to-peak(r=0.54,P＜0.05)of the SI-T curve were correlated to the severity of CP,respectively.However there was no linear correlation between the maximal signal enhancement rate and the severity of CP.Conclusion MR perfasion weighted imaging has a potential to diagnose and to grade experimental chronic pancreatitis.

Objective To observe the MRI findings of normal pancreas in piglets. Methods Eight healthy piglets underwent MR examination, and the morphology, size, signal intensity of pancreas were observed. After MR imaging, all piglets were abdominally incised to observe the anatomy of pancreas and pancreatic adjacent structures. The opening of both common bile duct and pancreatic duct were detected during operation. Two piglets were sacrificed after operation and the whole pancreases were dissected for anatomic research. Results The pancreas of piglets was composed of three parts: right lobe, median lobe and left lobe. All the lobes were displayed clearly on MRI. The signal intensity of pancreas was higher than that of liver and spleen on T1WI, whereas lower than that of liver and spleen on T2WI. On MRCP, pancreatic duct was not presented, whereas the common bile duct could be seen clearly. The opening of common bile duct located at superior part of duodenum (nearby the pylorus) and the opening of pancreatic duct situated at duodenal papilla corresponding to pancreatic right lobe. Conclusion MRI can show the pancreas of piglets very well. The morphology of pancreas and features of common bile duct conjunction with pancreatic duct in piglet are different from those in human.

This study was aimed to evaluate the effect of region of interest (ROI) on measurement of apparent diffusion coefficient (ADC) obtained in diffusion-weighted (DW) MR sequences between spinal tuberculosis and malignancy, selecting the more reasonable and effective measurement of ADC value. We collected the conventional MR sequences and diffusion-weighted imaging data of thirty-two patients with spinal tuberculosis or malignancy confirmed clinically and pathologically from August 2009 to June 2010. Using the conventional MRI as a guide, the signal intensity (SI) and ADC value were calculated by selecting single ROI and the same area multi-ROI within whole lesion at the largest slice of lesion respectively. Using ADC value defined by receiver operating characteristic (ROC) curve analysis as threshold, the sensitivity, specificity, and accuracy of ADC value for diagnosing spinal tuberculosis were compared. The results showed that the mean of ADC value at signal ROI was lower than that at the multi-ROI. There was no significant difference between the ADC value of single ROI and multi-ROI. The ADC values from spinal tuberculosis and spinal malignancy obtained in single ROI or multi-ROI showed significant differences. The sensitivity, specificity, and accuracy of ADC value for differentiating tuberculosis from neoplastic infiltration at signal ROI is lower than that at the multi-ROI. In conclusion, the ADC acquired multi-ROI can describe preferablywater molecular diffusion and is more useful in differentiating spinal tuberculosis from malignant bone marrow lesions.
Adult ; Algorithms ; Diagnosis, Differential ; Diffusion Magnetic Resonance Imaging ; methods ; Female ; Humans ; Image Interpretation, Computer-Assisted ; Male ; Middle Aged ; Spinal Neoplasms ; diagnosis ; Tuberculosis, Spinal ; diagnosis