Objective To investigate the radiation dose and image quality of spectral and conventional CT scan in neck.Methods Sixty patients with enhanced neck CT scan were analyzed retrospectively.The 30 patients with spectral CT scan were included in spectral CT group,and the 30 patients with conventional CT scan were included in conventional CT group.The tube voltage,tube current and rotation speed of the spectral CT group were fast switching with 80 and 140 kVp,630 mA and 0.5 s,respectively.The scanning parameters of conventional CT group were 120 kVp,auto tube current (100 to 600 mA),and 0.6 s,respectively.The objective evaluation [noise and (contrast to noise ratio) CNR] and subjective scores in the upper,middle and lower neck were evaluated.The radiation dose was also evaluated in the two groups.The independent-samples t test was used in comparison of the radiation dose.The independent-samples t test and the rank sum test were used to compare the objective and subjective image quality.Results The CT dose index of spectral and conventional scan in the neck were 17.77 mGy and (17.26±2.18) mGy,respectively without significant difference (t=-1.26,P=0.218).The noises of 65 keV images in upper,middle and lower neck were (4.5 ± 0.8),(4.5 ± 0.9),(5.2 ± 1.0) HU,and the noises of conventional CT images in above-mentioned regions were (4.5± 1.1),(4.1± 1.0),(5.0± 1.7) HU.There was no significant differences (t=0.102,-1.362,-0.621;P＞0.05).The subjective scores of 65 keV images in upper,middle and lower neck were (4.1 ± 0.3),(4.7 ± 0.5),(3.8 ± 0.7),while the subjective scores of conventional CT images in associated region were (4.1±0.4),(4.6 ±0.5),(3.5 ±0.6),wihtout significant differences (Z=-0.286,-0.531,-1.568;P＞0.05).The noises of 55 keV images in upper,middle and lower neck were (5.4±0.9),(5.6± 1.1),(6.6± 1.6) HU,which were significantly higher than noise of conventional images (t=-3.614,-5.560,-3.784;P＜0.05).The subjective scores of 55 keV images in upper and middle neck were (3.7±0.5),(4.2±0.4),which were significantly lower than those of conventional images (Z=-2.541,-3.136;P＜0.05).The subjective score of 55 keV images in lower neck was (3.3±0.8),which was no significant difference in comparison with conventional image (Z=-1.318,P＞0.05).There was no significant difference between the CNR of conventional images and CNR of spectral images with 65 keV and 55 keV in upper,middle and lower neck (P＞0.05).Conclusion The radiation dose and the image quality of spectral CT scan are same to the conventional CT scan in the neck,the 65 keV monochromatic images can be used routinely.

Objective This study aims to evaluate the changes of Cdk5 expression at the time of 3 hours to 10 days after moderate brain injury by blunt force impact in a rat model,and to demonstrate its forensic significance.Methods To establish a rat model of blunt focal brain contusion,and to observe the changes of Cdk5 expression in brain tissue at different timepoints after brain injury by immunohistochemistry and Western blot.Results A low expression level of Cdk5 was observed in the brain tissue of both normal and sham control groups.The expression of Cdk5 increased after 3 and 6 hours,remarkably increased at 12 hours,and reached the maximal level at 24 hours after focal brain injury.The Cdk5 level gradually decreased 3 days,5 days,7 days,and 10 days and reached the normal level 7 and 10 days after the injury,with no statistical difference (P＞0.05) compared with the normal and sham control groups.Conclusion The expression of Cdk5 increased in the peripheral area of contusion tissue after blunt brain injury in rats,showing single peak change,and dropped to normal level with the time extension.The change of Cdk5 expression may provide a new reference index for the prediction of early brain contusion.

Objective To observe and evaluate the short-term therapeutic effect of intravitreal injection with topotecan for refractory vitreous seeding from retinoblastoma (RB).Methods Eleven patients (11 eyes) of RB with refractory vitreous seeding (received intravenous chemotherapy,intra-arterial chemotherapy,intravitreal melphalan,laser,cryotherapy and subsequently developed refractory viable vitreous seeds) were enrolled in this study.There were 6 males (6 eyes) and 5 females (5 eyes).The aged from 9 to 44 months,with the mean age of 26 months.According to International Intraocular Retinoblastoma Classification,11 eyes were initially classified as group E (3 eyes),D (6 eyes),B (1 eye) or A (1 eye).All patients were received intravitreal injection with topotecan.A total of 32 intravitreal topotecan injections were performed with a mean of 2.9 injections (median 3 injections;range 2-4 injections).The mean follow-up was 10 months.The safety and effectiveness of intravitreal injection with topotecan for refractory vitreous seeding from RB were observed.Results Complete regression of vitreous seeds was achieved in 11 of 11 eyes (100％),including complete disappearance in 9 eyes and fibrosis in 2 eyes.None of the patients needed enucleation and occured ocular or systemic complications in the follow-up period.Conclusion Intravitreal injection with topotecan for refractory vitreous seeds from RB is effective and safe.

Talaromyces Marneffei infection is rarely reported in patients with chronic active Epstein-Barr virus (EBV) infection. We reported an old man with chronic fever, pleomorphic rash, cough, EBV viraemia, and secondary hemophagocytic syndrome. Repeated histological biopsy and culture of skin lesions revealed Talaromyces Marneffei. This patient was diagnosed as chronic active EBV infection, and Talaromyces Marneffei infection. After treated with glucocorticoid steroids and anti-fungal therapy, the patient finally recovered. EBV infection is usually seen in immune compromised patients, who are susceptible to opportunistic pathogens rarely as Talaromyces Marneffei in this case.