Objective: To explore the effect of pre- and post-adaptive statistical iterative reconstruction-Veo (ASiR-V) on image quality and radiation dose in paranasal sinus CT, and to find the best combinations. Methods: One head specimen was scanned with the routine spiral CT scanning parameters [noise index (NI)=8] and different levels of pre-ASiR-V (0—100%, with an interval of 10%). The images were reconstructed with different post-ASiR-V (0—100%, with an interval of 10%) for the bone algorithm and standard algorithm. All of 242 thin-layer images of paranasal sinuses were obtained. The region of interest (ROI) was selected to measure the CT value to calculate the contrast to noise ratio (CNR) and figure of merit (FOM). The volume CT dose index (CTDI_vol) and Smart mA were recorded. The linear regression was conducted to analyze the relationship between CTDI_vol, SmartmA, CNR and FOM. And with the same pose-ASiR-V level, the CNR of images which reconstructed by bone and soft algorithms were compared with pair-wise t test. The image quality was subjectively evaluated by three independent experienced radiologists using a 4-point scale (4 was the best). Results: As the pre-ASiR-V levels (0—100%) increased, Smart mA and CTDI_vol were reduced with a linear negative correlation (r=-0.981, -0.976, both P<0.001). The Smart mA decreased by 72.05% and CTDI_vol by 71.22%. Keeping the same pre-ASiR-V level,the CNR increased with the increase of post-ASiR-V level (for the bone algorithm images:R²=0.976, 0.992, 0.982, 0.982, 0.975, 0.975, 0.979, 0.996, 0.952, 0.978, 0.965;for the standard algorithm images: R²=0.944, 0.990, 0.988, 0.993, 0.996, 0.987, 0.984, 0.996, 0.996, 0.990, 0.965).Under the same level of post-ASiR-V, the CNR and FOM fluctuated with the pre-ASiR-V level (for the bone algorithm images:R²=0.335, 0.341, 0.344, 0.364, 0.385, 0.405, 0.418, 0.429, 0.455, 0.474, 0.516; for the standard algorithm images: R²=0.223, 0.278, 0.327, 0.285, 0.309, 0.329, 0.325, 0.346, 0.360, 0.390, 0.380). All subjective image quality could meet the diagnostic requirements (the score≥3). Conclusion At NI=8, for the bone algorithm, the best combination is 80% pre-ASiR-V and 100% post-ASiR-V; for the standard algorithm, the best iteration combination is 100% and 100%. The appropriate choice of pre- and post-ASiR-V levels in paranasal sinus CT scan can effectively reduce the radiation dose under the premise of maintaining the image quality that meets the diagnostic needs.

Objective To investigate the effect of the multi?material artifact reduction (MMAR) algorithm of spectral CT in reducing the beam hardening artifacts in dental restoration material. Methods Three?unit fixed bridge restorations were fabricated on the first to third molars in pig jaw. Gold alloy, zirconia, cobalt chromium alloy, nickel chromium alloy and pure titanium were used as materials for these fixed bridges. After restoration delivery, the pig jaw was scaned using energy spectrum CT machines. Images in regular 120 kVp scan mode were used as conventional group, and reconstructed single?energy horizontal images of 80, 90, 100, 110, 120, 130 and 140 keV in energy spectrum scanning mode were used as energy spectrum group, and reconstructed images applied MMAR technology in energy spectrum scanning mode were used as energy spectrum MMAR group. Each group was scanned 10 times to measure CT value and noise of muscles around dental prosthetic materials and adjacent non?artifact layers. Artifact index was calculated. Two radiologists scored the image quality of each group subjectively. Kruskal Wallis rank sum test was used to compare the difference of image noise, artifact index and subjective score among the control group and the best keV condition in the energy spectrum group and the energy spectrum MMAR group. Results The image noise of energy spectrum group and energy spectrum MMAR group decreased gradually with the increase of single energy level. The artifact index of pure titanium restorations in conventional group, energy spectrum group and energy spectrum MMAR group were 71.0±8.0, 21.4±2.7 and 14.7±2.7 respectively, and these values were significantly lower than those of other materials in the same group (P<0.05). The subjective image quality scores in energy spectrum MMAR group were as follows: 3.0±0.2 for gold alloy, 4.3±0.5 for zirconia, 3.0±0.4 for cobalt chromium alloy, 3.1±0.4 for cobalt chromium alloy, and 4.6± 0.5 for pure titanium. These scores were significantly smaller than those in the conventional group (P<0.05). There was no significant difference in noise between energy spectrum group and energy spectrum MMAR group (P>0.05), and the noise values in energy spectrum group and energy spectrum MMAR group were significantly lower than that in the conventional group (P<0.05). Conclusions Artifacts of pure titanium is minimal. Energy spectrum CT combined with MMAR technology can effectively reduce the artifacts of gold, zirconia, cobalt?chromium alloy, nickel?titanium alloy and pure titanium. This technique can be used as an effective method to remove artifacts of dental prosthesis.

Objective:To investigate the uncertainty of the dose measurements of superficial organs and the image noise in CT scanning.Methods:GE Revolution CT was used to perform 20 repeated scans on the isolated skull specimen in sequential and helical mode. The chest phantom was scanned for 45 times with the pitch 1.0 and the collimation 80 mm for two scanners (GE Revolution CT, Philips Brilliance iCT) and 40 mm for the Siemens Somatom Definition Flash CT. The volume CT dose index (CTDI vol) was maintained during the above scannings. A dosimeter was used to measure the dose at the position of the right eye lens of the specimen and the center of right breast of the chest phantom. The position of dosimeter sensor remained unchanged. The standard deviation of CT values (image noise) in the air region of cross-sectional images at the center of the sensor reconstructed with lung/soft tissue algorithms were measured. The mean values ( Av), standard deviations ( SD), coefficients of variation ( CV) and relative ranges ( RR) of the dosimetric values and the standard deviations of CT values of 3, 5, 10, 20, 30 and 45 scans were calculated. Pearson and Spearman correlation analysis were used to evaluate the correlation between the dosimetric values and the standard deviations of CT values. Results:The measured dosimetric values of the skull specimen were almost unchanged in the sequential scannings. The relative range of dose in helical mode was 10.67%. The relative ranges of the measured values of the three CT scanners for 45 scans reached 43.83%, 25.31%, and 14.32%. The standard deviations of CT values of the lung/soft tissue images varied greatly and the differences were not completely related to the dosimetric values.Conclusions:The dosimetric values of superficial organs were stable in the sequential scanning mode. The dose measurements of superficial organs and the image noise changed greatly in helical scanning mode.

Objective:To investigate the effect of Guilu Erxian Jiao (GEJ) on the negative feedback function of hypothalamic-pituitary-adrenal (HPA) axis and its possible mechanism in rats with post-traumatic stress disorder(PTSD).Methods:The PTSD rat model was established using single prolonged stress (SPS). Ninety six SD rats were randomly divided into control group (control), model group (SPS), GEJ group (GEJ) and paroxetine group (PRX) according to the random number table with 24 rats in each group. Except the control group, the rats in the other groups were constructed using the PTSD model. On the 8th day after the establishment of the model, the rats of the GEJ group (3.6 g/kg) and the PRX group (10 mg/kg) were respectively given the drug by gavage for 21 days. The rats in control group and SPS group were given the same amount of distilled water once a day for 21 days. After continuous administration for 21 days, 12 rats were randomly selected from each group for the dexamethasone suppression test (DST), then 6 rats were selected for the RT-PCR, and the remaining 6 rats were used for immunohistochemistry. The contents of plasma adrenocorticotrophic hormone (ACTH) were measured by Elisa. The expression levels of glucocorticoid receptor (GR), mineralocorticoid receptor (MR), adrenocorticotropic hormone releasing factor Ⅰ receptor (CRF1R) and adrenocorticotropic hormone releasing factor Ⅱ receptor (CRF2R) were detected by RT-PCR and immunohistochemistry.Results:(1) In DST, plasma ACTH level in SPS group was significantly lower than that in control group((145.89±19.41)μg/L, (203.59±35.78)μg/L, t=3.16, P<0.01), and that in the PRX group and GEJ group were significantly higher than that in SPS group((218.47±37.55)μg/L, t=3.98, P<0.01; (205.33±66.54)μg/L, t=3.26, P<0.01). (2) RT-PCR results showed that, in hippocampus, the GR mRNA and MR mRNA expressions in SPS group were significantly higher than those in control group((1.29±0.02), (1.00±0.06), t=6.88, P<0.01; (1.38±0.02), (1.00±0.05), t=7.97, P<0.01), and that in the GEJ group significantly decreased comparing to SPS group((0.96±0.07), t=7.87, P<0.01; (0.86±0.13), t=11.03, P<0.01). (3) Immunohistochemical results showed that, in hippocampus, the positive cell expressions of GR and MR in the SPS group were significantly higher than those in control group((84.33±12.82), (69.33±8.19), t=2.50, P<0.05; (77.33±6.65), (56.33±11.79), t=2.25, P<0.05), and that in the GEJ group significantly were lower than SPS group((68.33±4.55), t=2.67, P<0.05; (59.50±4.18), t=2.25, P<0.05). In amygdala, the positive cells expression of GR, MR and CRF1R in the SPS group significantly decreased compared with the control group((62.67±6.89), (77.17±10.70), t=3.10, P<0.05; (60.50±11.66), (91.83±15.63), t=3.43, P<0.05; (54.50±19.96), (88.17±22.43), t=2.31, P<0.05); and that in GEJ group significantly increased compared with the SPS group((74.33±5.85), t=2.11, P<0.05; (83.67±12.55), t=2.53, P<0.05; (88.67±16.28), t=2.35, P<0.05). Conclusion:GEJ can inhibit the enhanced HPA axis negative feedback function induced by SPS, which may be related to regulating expression of GR, MR and CRF1R in the hippocampus and amygdala.

Objective:To investigate the feasibility of simultaneous arteriovenous enhancement of neck CT with two-stage injection of contrast agent and its effect on image quality and radiation dose.Methods:A total of 30 patients undergoing neck CT enhancement scan due to space-occupying lesions in Beijing Tongren Hospital, Capital Medical University from February to April 2022 were prospectively included as the experimental group. The neck CT enhancement scan was performed with two-stage injection of contrast agent and arteriovenous simultaneous enhancement. The dosage of contrast agent was calculated according to the patient′s body weight, and the method of two-stage injection was adopted. The dosage of contrast agent in the first stage was 0.7 ml/kg, with normal saline in the middle stage, and the second stage (began at 35 s) was 0.3 ml/kg. A total of 30 patients with gender and age matching with the experimental group from December 2021 to January 2022 were retrospectively collected as the control group. The control group was treated with the traditional arterial phase and venous phase scanning method with the dosage of 1.0 ml/kg contrast agent. The arterial phase was scanned at the 30 s and the venous phase was scanned at the 60 s. The CT values of bilateral carotid arteries and jugular veins in the experimental group were measured, the CT values of bilateral carotid arteries in the arterial phase were measured in the control group, and the CT values of bilateral carotid arteries and jugular veins in the venous phase were measured. Carotid artery enhancement score was performed for images of experimental group and control group in arterial and venous phase, and jugular vein and lesion enhancement score was performed for images of experimental group and control group in venous phase. The effective dose was calculated for both groups. The difference of carotid artery CT values between images was compared by one-way analysis of variance, and LSD method was used for pairwise comparison. The CT values of jugular vein were compared using independent sample t test. Kruskal-Wallis test was used to compare carotid artery enhancement scores, and Nemenyi method was used for pairwise comparison. Jugular vein and lesion enhancement scores and effective dose were compared by Mann-Whitney U test. Results:The CT value of carotid artery of experimental group [left (276±24) HU, right (273±25) HU] was lower than that of control group in arterial phase [left (329±33) HU, right (327±32) HU], and higher than that in the venous phase [left (147±15) HU, right (148±16) HU]. All the differences were statistically significant ( P<0.001). The CT value of jugular vein of experimental group [left (206±18) HU, right (203±19)] was higher than that of control group in the venous phase [left (154±15) HU, right (151±15)], the difference was statistically significant ( t=11.88, 11.76, both P<0.001). There was no significant difference in carotid artery enhancement score between experimental group and control group in arterial phase ( P=0.624), but the carotid artery enhancement score of the experimental group was higher than that of the control group in the venous phase, and the difference was statistically significant ( P<0.001). The scores of jugular vein and lesion enhancement in experimental group were higher than those of control group in venous phase, and the difference was statistically significant ( Z=5.01, P<0.001). The effective dose of the experimental group [2.41(2.04, 2.72) mSv] was decreased by 52.2% compared with the control group [5.04(4.18, 5.44) mSv], and the difference was statistically significant ( Z=-6.24, P<0.001). Conclusions:The neck CT enhanced scan with two-stage injection of contrast agent and arteriovenous simultaneous enhancement method can obtain comprehensive images of arterial and venous phases, and realize simultaneous enhancement of carotid artery, jugular vein and lesions, and reduce radiation dose.

Objective:To investigate the trend of radiological diagnostic examination frequency and the related influencing factors in a general hospital in recent four years.Methods:The hospital information system and the radiology information system were used to collect the information on the numbers of the outpatients, the emergency patients, and the inpatients and the radiology examination information from 2019 to 2022. The examination frequency and proportion of various imaging equipment were counted by using the perspective table of data, and the examination items and the proportion of the radiological diagnostic examinations were calculated. The positive rates of the radiological examinations were measured from 2019 to 2022. The gender and age distribution of the patients were analyzed. Spearman correlation analysis was used to analyze the relationships between the numbers of the patients undergoing radiological examinations and the numbers of the outpatients, emergency patients and the inpatients.Results:The annual frequency of radiological diagnostic examinations from 2019 to 2022 were 307 306, 245 418, 317 250 and 325 625, respectively, with a total of 1 195 599. Among them, the proportions of CT, X-rays, bedside X-rays, bone density, gastrointestinal imaging and mammography were 59.74%, 38.04%, 1.39%, 0.42%, 0.21% and 0.19%, respectively. In each year, the proportion of CT in all radiological diagnostic examinations was 49.58%, 63.40%, 60.40% and 65.20%, respectively. The frequency of emergency CT and emergency chest CT was correlated with the number of emergency patients( r =0.63, 0.61, P<0.05), and the frequency of non-emergency CT was correlated with the number of outpatients and inpatients ( r =0.61, 0.66, P<0.05). The positive rates of the CT examinations were higher than 80% except the lowest of 79.95% in 2021. Conclusions:Radiological examinations especially CT examinations have increased significantly, and played an important role in the diagnosis of diseases. However, attention should be paid to the Justification of the CT examinations. Timely statistical analysis of radiological examination information can provide data supports and references for scientific management of radiological examinations.

Objective:To explore the strategy and experience for treating maxillofacial and cervical multi-space infection combined with descending necrotizing mediastinitis (DNM) via multidisciplinary team (MDT) collaboration.Methods:A total of 36 patients with maxillofacial and cervical multi-space infection complicated with DNM admitted to the First Affiliated Hospital of Zhengzhou University from July 2011 to July 2019 were included in the study. The clinical data of the patients were retrospectively analyzed, including gender, age, symptoms at admission, source of infection, preoperative and postoperative evaluation indicators, MDT strategy and prognosis.Results:There were 26 males and 10 females with an average age of (51.6±17.6) years (8-80 years). The course of disease before admission was (8.9±8.4) days (2-30 days). All patients were admitted with maxillofacial and neck swelling and pain as the main complaints. Odontogenic infection accounted for 39% (14/36), throat floor swelling and pain accounted for 25% (9/36) and unknown maxillofacial swelling accounted for 36% (13/36). There were 28 cases receiving surgical treatment, 26 cases were cured and discharged (72%), 10 cases died (28%). In the patients treated with multidisciplinary therapy (mainly by surgery), the white blood cell count, neutrophil percentage, C-reactive protein and procalcitonin levels were significantly improved compared with those at admission at each observation time point after operation ( P<0.05). The length of stay was positively correlated with the levels of C-reactive protein ( r=0.545, P<0.05) and procalcitonin ( r=0.504, P<0.05). The prognosis of patients treated with surgery (26/28) was better than that of patients without surgery (0/8) ( P<0.01). Conclusions:The patients with maxillofacial and cervical multi-space infection combined with DNM might be in critical condition. The surgical based MDT strategy has an important impact on the prognosis of patients. White blood cell count and other inflammatory indicators monitoring can effectively observe the changes of the patient′s condition.

Objective:To evaluate the effect of short-chain fatty acids on microglial synapse engulfment in aged rats with postoperative cognitive dysfunction (POCD).Methods:Forty-eight healthy male Sprague-Dawley rats, aged 18 months, weighing 520-650 g, were divided into 4 groups ( n=12 each) using a random number table method: control group (group C), short-chain fatty acids group (group S), POCD group (group P), and POCD+ short-chain fatty acids group (group PS). Rats received short-chain fatty acids (sodium propionate 25.9 mmol/L, sodium butyrate 40 mmol/L and sodium acetate 67.5 mmol/L) in the free drinking water for 28 days in S and PS groups. On day 29, anesthesia was induced with 4%-5% sevoflurane and maintained with 3% sevoflurane, and the tibial fracture internal fixation was performed to prepare a rat model of POCD in P group and PS group. Morris water maze test was performed at day 7 after surgery. The escape latency, times of crossing the original platform, mean swimming speed and time spent in the original platform quadrant were recorded. The rats were sacrificed at the end of Morris water maze test, and the brains were collected to analyze the number and density of dendritic spines in the hippocampal CA1 region (by Golgi staining) and to determine the expression of postsynaptic density 95 (PSD95) and complement 1q (C1q) in the hippocampal CA1 region (by immunofluorescence). Results:Compared with group C, the times of crossing the original platform were significantly decreased, the time spent in the original platform quadrant was shortened, the escape latency was prolonged, the number and density of dendritic spines and the number of intersection points between dendrites and concentric circles were decreased, the expression of PSD95 was down-regulated, and the expression of C1q was up-regulated in P and PS groups ( P<0.05). Compared with group P, the times of crossing the original platform were significantly increased, the time spent in the original platform quadrant was prolonged, the escape latency was shortened, the number and density of dendritic spines and the number of intersection points between dendrites and concentric circles were increased, the expression of PSD-95 was up-regulated, and the expression of C1q was down-regulated in group PS ( P<0.05). Conclusions:The mechanism by which short-chain fatty acids attenuates POCD is related to decreased microglial engulfment of synapses in aged rats.

Objective: To investigate the effect of the multi-material artifact reduction (MMAR) algorithm of spectral CT in reducing the beam hardening artifacts in dental restoration material. Methods: Three-unit fixed bridge restorations were fabricated on the first to third molars in pig jaw. Gold alloy, zirconia, cobalt chromium alloy, nickel chromium alloy and pure titanium were used as materials for these fixed bridges. After restoration delivery, the pig jaw was scaned using energy spectrum CT machines. Images in regular 120 kVp scan mode were used as conventional group, and reconstructed single-energy horizontal images of 80, 90, 100, 110, 120, 130 and 140 keV in energy spectrum scanning mode were used as energy spectrum group, and reconstructed images applied MMAR technology in energy spectrum scanning mode were used as energy spectrum MMAR group. Each group was scanned 10 times to measure CT value and noise of muscles around dental prosthetic materials and adjacent non-artifact layers. Artifact index was calculated. Two radiologists scored the image quality of each group subjectively. Kruskal Wallis rank sum test was used to compare the difference of image noise, artifact index and subjective score among the control group and the best keV condition in the energy spectrum group and the energy spectrum MMAR group. Results: The image noise of energy spectrum group and energy spectrum MMAR group decreased gradually with the increase of single energy level. The artifact index of pure titanium restorations in conventional group, energy spectrum group and energy spectrum MMAR group were 71.0±8.0, 21.4±2.7 and 14.7±2.7 respectively, and these values were significantly lower than those of other materials in the same group (P<0.05). The subjective image quality scores in energy spectrum MMAR group were as follows: 3.0±0.2 for gold alloy, 4.3±0.5 for zirconia, 3.0±0.4 for cobalt chromium alloy, 3.1±0.4 for cobalt chromium alloy, and 4.6±0.5 for pure titanium. These scores were significantly smaller than those in the conventional group (P<0.05). There was no significant difference in noise between energy spectrum group and energy spectrum MMAR group (P>0.05), and the noise values in energy spectrum group and energy spectrum MMAR group were significantly lower than that in the conventional group (P<0.05). Conclusions Artifacts of pure titanium is minimal. Energy spectrum CT combined with MMAR technology can effectively reduce the artifacts of gold, zirconia, cobalt-chromium alloy, nickel-titanium alloy and pure titanium. This technique can be used as an effective method to remove artifacts of dental prosthesis.