Objective To evaluate the clinical value of spectral CT monochromatic imaging in improvement of imaging quality of bronchial arteries.Methods We retrospevtively analyzed the chest CT images in 38 patients who underwent the contrast-enhanced spectral CT.These images included a set of 140 kVp polychromatic images and default 70 keV monochromatic images.Using a standard Gemstone Spectral Imaging (GSI)viewer at an advanced workstation (AW4.6),an optimal energy level (in keV)for obtai-ning the best CNR of the bronchial artery could be automatically obtained.The SNR,CNR and objective imaging quality score for these 3 imaging sets (140 kVp,70 keV and optimal energy level)were obtained and compared with one-way ANOVA .Results The optimal energy levels for obtaining the best CNR were (62.58±2.74)keV.The SNR of the 140 kVp polychromatic images,70 keV monochromatic images,and the optimal keV monochromatic images were 1 6.44±5.85,20.96 ±8.32 and 24.91 ±9.91,the CNR were 13.30±5.45,1 7.25±6.97 and 20.67±8.62,and the subjective imaging quality scores were 1.97 ±0.82,3.24±0.75 and 4.47±0.60,respectively,exhibiting significant differences among groups (F =10.1 7,10.1 7 and 1 1 1.12,P <0.00).The optimal monochromatic group was superior to the 70 keV group and the 140 kVp mixed-energy group.Conclusion Monochromatic images at approximately 62 keV in dual-energy spectral CTA yields the best CNR and highest diagnostic confidence for imaging bronchial ar-teries,which may improve imaging quality for imaging bronchial arteries.

Objective To compare the virtual non-enhanced chest CT (VNCT)generated from spectral CT with conventional non-enhanced chest CT in patients with lung disease in terms of CT number accuracy and image quality.Methods A total of 30 patients with lung disease proved by pathology underwent the conventional non-enhanced thoracic CT and contrast enhanced CT with spectral imaging mode in arterial phase (AP)and venous phase (VP).The VNCT images were reconstructed based on the enhanced spectral CT imaging data.The mean CT number,signal to noise ratio (SNR)for the lesions and image quality score were obtained and compared between the true non-contrast CT (TNCT)and the VNCT (including AP and VP)with paired t test.Results The mean±standard deviation for CT number were (38.74±5.17)HU,(39.08±5.07)HU and (38.96± 5.18)HU for TNCT,VNCT at AP and VNCT at VP,respectively, with no statistical difference (P>0.05).All 3 sets of images demonstrated acceptable image quality,even though there were statistically significant differences in the SNR value and image quality score.The mean ± standard deviation values for SNR were 4.74±0.42 with TNCT, 3.79 ± 0.5 1 with VNCT at AP and 3.77 ± 0.39 with VNCT at VP (P <0.05),and the image quality scores were 5.00 ±0.00 with TNCT,4.17±0.65 with VNCT at AP and 4.17±0.53 with VNCT at VP (P<0.05).Conclusion In patients with lung disease,the vir-tual non-enhanced CT images generated from spectral CT provide accurate CT numbers for lesions and acceptable image quality com-pared with the true non-contrast CT.VNCT may be used to replace TNCT to improve work flow and reduce radiation dose.

Objective To explore the value of the spectral CT iodine-based material decomposition technique in differential diagnosis of central pulmonary carcinoma from obstructive pneumonia and atelectasis.Methods 25 cases with central pulmonary carcinoma complicating with obstructive pneumonia and atelectasis underwent CT plain scan and spectral contrast scan including pulmonary-arterial-phase (PAP) and bronchial-arterial-phase(BAP).Conventional CT images and iodine base images were generated in each phase by GSI viewer.The 4 groups of images differences between the tumor and the obstructive pneumonia and atelectasis were analyzed.Results The margin of the tumor was ill-defined in plain scan.The cases that showed difference between the tumor and the obstructive pneumonia and atelectasis in 4 groups of images were respectively as follows,10 in conventional CT images of PAP,1 6 in conventional CT images of BAP,1 9 in iodine base images of PAP,and 23 in iodine base images of BAP.The difference of the 4 groups was significant (χ2 =16.54,P<0.05).There was the highest accuracy in iodine base images of BAP in defining the tumor margin (χ2 = 12.83,χ2 = 4.20,χ2 =1.34,P <0.05). The accuracy between conventional CT images of BAP and iodine base images of PAP had no significant differences (χ2 =0.86,P >0.05),but were better than that of the conventional CT images of PAP(χ2 =6.65,P <0.05).Conclusion Spectral CT iodine-based material decomposition technique is helpful to improve subjective diagnosis of central pulmonary carcinoma complicating with obstructive pneumonia and atelectasis,especially in iodine base images of BAP,it can provide accurate information for clinical stage and treatment.

Objective:To summarize the atypical manifestations and treatment strategies of serous microcystic neoplasm of the pancreas.Methods:Review the case data of 11 cases of pancreatic serous microcystic adenoma with atypical preoperative clinical imaging findings admitted to Peking Union Medical College Hospital from July 2008 to October 2019, and summarize their clinical manifestations, CT/MRI features, and preoperative clinical diagnosis, surgical methods, postoperative conditions.Results:The median age of the 11 patients was 50 (46-66) years old, 7 females, and 4 males. There were 8 cases with back pain and 6 cases with weight loss. The preoperative imaging examination found that the lesion was located in the head and neck in 8 cases, with pancreaticobiliary duct dilatation in 7 cases, suspected vascular invasion in 3 cases, and pancreatic parenchymal atrophy in 2 cases, 3 cases showed rich blood supply and solid space, and 2 cases were connected to the pancreatic duct. Preoperative diagnosis of pancreatic malignant tumors accounted for 4 cases, neuroendocrine tumors in 3 cases, solid pseudopapillary tumors in 3 cases, and intraductal papillary mucinous tumors in 1 case. All patients underwent surgical treatment, 3 cases of distal pancreatectomy (2 cases of using Kimura method to protect the spleen), 3 cases of pancreaticoduodenectomy, 1 case of total pancreatectomy, 2 cases of pancreatic head resection with duodenum preservation, 2 cases of local resection. All patients had no early postoperative deaths. There were 2 cases of grade B pancreatic fistula, 2 cases of biochemical leakage, 1 case of postoperative abdominal hemorrhage, and 2 cases of delayed gastric emptying, all of which were cured after active treatment. The median postoperative hospital stay was 18 (7-63) days.Conclusions:Pancreatic serous microcystic neoplasm could be accompanied by atypical features such as pancreatic/bile duct dilation, parenchyma atrophy, or even present vessel invasion. Understanding the atypical clinic and image features would help improving differential diagnosis and treatment. For those with invasive features, surgical exploration should be recommended.

Functionalized graphene oxide is prepared based on graphene. It has attracted great interest from all over the world due to its good solubility, biocompatibility, high loading rate, and easy modification. This paper summarizes the surface modification of graphene oxide, and its applications on anti-tumor, antibacteria, anti-hypertension, gene therapy and biosafety as a drug carrier, providing new methods and ideas in the biomedical field.