In vivo tracing of superparamagnetic iron oxide-labeled bone marrow mesenchymal stem cells transplanted for traumatic brain injury by susceptibility weighted imaging in a rat model / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To label rat bone marrow mesenchymal stem cells (BMSCs) with superparamagnetic iron oxide (SPIO) in vitro, and to monitor the survival and location of these labeled BMSCs in a rat model of traumatic brain injury (TBI) by susceptibility weighted imaging (SWI) sequence.</p><p><b>METHODS</b>BMSCs were cultured in vitro and then labeled with SPIO. Totally 24 male Sprague Dawley (SD) rats weighing 200-250 g were randomly divided into 4 groups: Groups A-D (n equal to 6 for each group). Moderate TBI models of all the rats were developed in the left hemisphere following Feeney's method. Group A was the experimental group and stereotaxic transplantation of BMSCs labeled with SPIO into the region nearby the contusion was conducted in this group 24 hours after TBI modeling. The other three groups were control groups with transplantation of SPIO, unlabeled BMSCs and injection of nutrient solution respectively conducted in Groups B, C and D at the same time. Monitoring of these SPIO-labeled BMSCs by SWI was performed one day, one week and three weeks after implantation.</p><p><b>RESULTS</b>Numerous BMSCs were successfully labeled with SPIO. They were positive for Prussian blue staining and intracytoplasm positive blue stained particles were found under a microscope (200). Scattered little iron particles were observed in the vesicles by electron microscopy (5000). MRI of the transplantation sites of the left hemisphere demonstrated a low signal intensity on magnitude images, phase images and SWI images for all the test rats in Group A, and the lesion in the left parietal cortex demonstrated a semicircular low intensity on SWI images, which clearly showed the distribution and migration of BMSCs in the first and third weeks. For Group B, a low signal intensity by MRI was only observed on the first day but undetected during the following examination. No signals were observed in Groups C and D at any time points.</p><p><b>CONCLUSION</b>SWI sequence in vivo can consecutively and noninvasively trace and demonstrate the status and distribution of BMSCs labeled with SPIO in the brain of TBI model rats.</p>

Characteristic analysis on susceptibility weighted imaging of intravitreous foreign body of autologous eyelashes in rabbits / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To explore the characteristics of susceptibility weighted imaging (SWI) of the intravitreous foreign body of autologous eyelashes in rabbits.</p><p><b>METHODS</b>A total of 12 New Zealand white rabbits, either sex, weighing 2.5-3.5 kg, and provided by the Experimental Animal Center of Henan Province were employed in this study. For each rabbit, 5 autologous eyelashes (1 cm in length and 0.2-0.3 mm in diameter) were implanted into the right ocular vitreum, while the left control ocular vitreum received sham operation but nothing was implanted. SWI sequential test was made 2 hours postoperatively. Then the rabbits were killed and the specimens of the vitreous bodies of the rabbits were obtained. Hematoxylin and eosin staining and histological examinations were performed.</p><p><b>RESULTS</b>The autologous eyelashes in 8 ocular vitreums of rabbits showed linear low signal intensity on the magnitude images and susceptibility weighted images, but linear high signal intensity on the phase images. Among the 12 experimental rabbits, 5 eyelashes in the right vitreum were completely shown in 3 rabbits, partly shown in 5 rabbits (2 eyelashes shown in 3 rabbits and 3 eyelashes shown in 2 rabbits), and not shown in 4 rabbits.</p><p><b>CONCLUSIONS</b>SWI of the foreign body of intravitreous autologous eyelashes in rabbits has its own characteristics. The combined application of SWI sequential magnitude images, susceptibility weighted images and phase images is helpful to the detection and diagnosis of intravitreous autologous eyelashes in rabbits.</p>

Formation and suppression technique for motion and flow artifacts on magnetic resonance imaging / 中国医疗器械杂志

During magnetic resonance imaging, motion and flow artifacts often severely decrease image quality. The mechanisms of these kinds of artifacts are very complex. This article reviewed the pre-handling techniques of motion and flow artifacts, such as changing magnetic resonance imaging parameters, using spatial pre-saturation pulse sequences, gating and triggering techniques of suppressing respiratory motion artifact, as well as the progress of magnetic resonance pulse sequences in suppressing motion and flow artifacts, The paper briefly introduced post-processing techniques of suppressing motion and flow artifacts.