Objective To investigate the value of susceptibility weighted imaging (SWI) in the diagnosis of hemorrhagic diffuse axonal injury (DAI). Methods A retrospective study was conducted on 20 patients with DAI who received MRI examination at day 3 post-injury.MRI sequences included T1WI,T2WI,fluid attenuated inversion recovery ( FLAIR),diffusion weighted imaging (DWI) and SWI.There were 15 patients with the Glasgow Coma Scale (GCS) score≤8,three with GCS score of 9-12 and two with GCS of 13-15.The location and quantity of hemorrhage focus were counted.The area of hemorrhage focus was measured on each MR sequence.Differences of detection rate of hemorrhage focus on each sequence were compared by using X2 test.The correlation between DAI related bleeding area and GCS score was analyzed. Results DAI related hemorrhage focus showed a larger number in superficial cerebrum than that in posterior cranial fossa and in deep cerebrum.The detection rate of hemorrhage focus on SWI was the highest,as compared with other sequences ( P ＜ 0.05 ).Bleeding area and GCS score showed a negative correlation (r =-0.921,P ＜ 0.01 ). Conclusion SWI is very sensitive in detection of the intracerebral hemorrhage focus in the acute period of traumatic DAI.

Background and Objectives: Chronic periodontitis can lead to alveolar bone resorption and eventually tooth loss. Stem cells from exfoliated deciduous teeth (SHED) are appropriate bone regeneration seed cells. To track the survival, migration, and differentiation of the transplanted SHED, we used super paramagnetic iron oxide particles (SPIO) Molday ION Rhodamine-B (MIRB) to label and monitor the transplanted cells while repairing periodontal bone defects. Methods: and Results: We determined an appropriate dose of MIRB for labeling SHED by examining the growth and osteogenic differentiation of labeled SHED. Finally, SHED was labeled with 25 μg Fe/ml MIRB before being transplanted into rats. Magnetic resonance imaging was used to track SHED survival and migration in vivo due to a low-intensity signal artifact caused by MIRB. HE and immunohistochemical analyses revealed that both MIRB-labeled and unlabeled SHED could promote periodontal bone regeneration. The colocalization of hNUC and MIRB demonstrated that SHED transplanted into rats could survive in vivo. Furthermore, some MIRB-positive cells expressed the osteoblast and osteocyte markers OCN and DMP1, respectively. Enzyme-linked immunosorbent assay revealed that SHED could secrete protein factors, such as IGF-1, OCN, ALP, IL-4, VEGF, and bFGF, which promote bone regeneration. Immunofluorescence staining revealed that the transplanted SHED was surrounded by a large number of host-derived Runx2- and Col II-positive cells that played important roles in the bone healing process. Conclusions SHED could promote periodontal bone regeneration in rats, and the survival of SHED could be tracked in vivo by labeling them with MIRB. SHED are likely to promote bone healing through both direct differentiation and paracrine mechanisms.