Objective To explore the role of 256 CT iterative reconstruction in improving image quality and reducing radiation dose of carotid artery into cranial segment.Methods Sixty patients underwent head and neck CTA on a 256 CT scanner.Conventional dose scanning was performed in 30 patients using a filtered back projection (FBP) reconstruction (group A) and iterative iDose4 reconstruction (group B).Low dose scanning was performed in the other 30 patients using FBP reconstruction (group C) and iDose4 reconstruction (group D).The noise,SNR,CNR,score of image quality and effective radiation dose were evaluated in four groups.One-way ANOVA was used to analyze the image quality index between groups.Independent sample of Kruskal-Wallis test of ranked data was used to compare image quality score between groups.Paired t test was used to compare the effective radiation doses between the low dose group and conventional dose group.Results The image noise of four groups were 8.21 ±0.88,7.31 ± 0.33,11.17 ± 2.02 and 6.50 ± 0.49 respectively.SNR were 43.21 ± 4.49,5 1.83 ± 3.64,42.88 ± 9.19 and 53.47 ± 4.88,respectively.CNR were 37.88 ± 4.02,61.21 ± 6.31,36.63 ± 8.20 and 62.99 ±5.90,respectively.There were statistic differences (F =112.786,97.041 and 86.098,P ＜0.01).The differences of image noise between group A and B had no statistic significance,which was statistic different between group A and C (P ＜ 0.01).Except that the differences of SNR and CNR between group A and C,B and D had no statistic significance,the differences between other two groups had statistic significance (P ＜ 0.01).In case of image quality score of 1,2 and 3,there were 2,13 and 15 patients in group A; 0,7 and 23 patients in group B; 5,15 and 10 patients in group C; and 0,5 and 25 patients in group D.There was statistic differences of image quality score between each group (H =22.575,P ＜0.01).The effective radiation dose was (2.31 ±0.13) mSv in conventional dose group and (0.84 ±0.04) mSv in low dose group.There was statistic difference between the two groups (t =60.682,P ＜ 0.05).Conclusion Compared with conventional dose,iDose4 iterative reconstruction algorithms can obtain excellent images of CTA for carotid artery into the cranial segment with more than 50％ radiation dose decrease.

Objective To determine the diagnostic value of double-phase enhancement and virtual endoscopy with multi-slice spiral CT (MSCT) on clinical staging of preoperative bladder cancer.Methods Seventy-five patients with bladder cancer diagnosed by fibercystoscope or operation. All of them were examined by double-phase enhancement and virtual endoscopy with MSCT. The images were analyzed and clinical staging were obtained. The findings of MSCT (71 cases)were compared with the post-operative histopathological results. Results There were 94 lesions to be found. The staging of MSCT: T1 26 cases,T2, 27 cases, T2b 13 cases, T3 12 cases, T4 16 cases. Histopathological results: pT1 28 cases, pT2a 24 cases, pT2b 14 cases, pT3 12 cases, pT4 16 cases. The sensitivity of preoperative staging on bladder cancer was 89.4 % (84/94) by double-phase enhancement of MSCT;the sensitivity of virtual endoscopy was 96.6% (84/87)for polyploidy tumors and 90. 9 % (10/11) for sessile lesions. When double-phase enhancement and virtual images were evaluated together, the sensitivity rate increased to 94.5%. When the tumors were confined within the bladder wall (≤T2b), the diagnostic accuracy of double-phase enhancement and virtual images was 91.2% (51/56). When the tumors had invaded the tissues and organs beyond the bladder wall (≥T3), the accuracy was 100% (28/28). Conclusion Double-phase enhancement and virtual endoscopy of MSCT is of great value in clinical staging of bladder cancer.

Objective To explore the image quality and diagnostic efficiency of coronary CTA (CCTA) in patients without heart rate (HR) control by optimizing acquisition phase with auto-ECG-gating technology using 256-row wide-volume detector.Methods Totally 200 patients with suspected coronary artery disease (CAD) were selected and underwent CCTA with auto-ECG-gating on a 256 row wide detector CT (Revolution CT).Patients were divided into 4 groups according to the real-time HR,group A (n=50):HR≤69 bpm;group B (n=50):HR 70-80 bpm;group C (n=50):HR 81-90 bpm;group D:HR≥91 bpm (n=50).CCTA images quality and diagnostic rate were assessed by two experienced radiologists blindly,and effective radiation dose were compared among 4 groups.Results There were no significant differences of age,sex,and body mass index among 4 groups (all P＞0.05),and there was significant difference of image quality score among 4 groups (P＜0.05).Totally,800 coronary arteries and 2 575 segments in 200 patients were assessed.There had no significant difference of diagnostic rate among four groups derived from the segment,coronary artery and patients (all P＞0.05).The effective radiation dose in A D groups were (1.05t0.48)mSv,(2.41± 1.20)mSv,(1.27±0.55) mSv,(2.66±1.12)mSv,and the difference was significant (F=29.22,P＜0.001).Conclusion It is feasible to perform CCTA in single cardiac cycle in patients with arbitrary heart rate by auto-ECG-gating using Revolution CT equipped widevolume detector.And it can improve image quality and success ratio in patients with moderate and high heart rate.

Objective To explore the value of enhanced T2 *-weighted angiography (ESWAN) sequence in displaying the intracranial deep vein distension in full-term neonates with hypoxic-ischemic encephalopathy (HIE).Methods Thirty-two confirmed cases of full-term neonates confirmed with HIE and 10 cases of normal full-term neonates received the brain magnetic resonance imaging(MRI) ESWAN sequence scanning.The display rate of intracranial deep vein in normal group and HIE group with mild,moderate and severe degree was evaluated.The differences in intracranial deep vein display rate between the normal group and the HIE group or within different degrees of HIE patients were compared respectively to observe the relationships between intracranial ischemic lesion and deep vein conditions.The role of ESWAN sequence in the diagnosis of HIE was evaluated.Results The display rate of intracranial deep vein in normal group was 26.2％ (21/80 cases) ;the display rate of intracranial deep vein in mild,moderate and severe HIE groups were 59.8％ (67/112 cases),92.3％ (96/104 cases) and 95.0％ (38/40 cases),respectively.The differences of intracranial deep vein display rate between normal group and mild HIE group were statistically significant (P ＜ 0.05) ; the differences of intracranial deep vein display rate between the slight HIE group and moderate HIE group were statistically significant (P ＜ 0.05) ;the differences of intracranial deep vein display rate between the moderate HIE group and severe HIE group were not statistically significant(P ＞ 0.05).The distribution of intracranial deep vein distension and ischemic lesion in HIE group was consistent.Conclusions ESWAN sequence can clearly show the relationship between intracranial venous distension and ischemic lesion,which has diagnostic value in judging the location and extent of HIE.It can indicate the severity of HIE by displaying secondary distension of intracranial vein.

Objective:To explore effective schemes for improving cognitive function in patients with subjective cognitive decline (SCD) by EEG neurofeedback (NF) technique.Methods:Ten SCD patients recruited in Department of Neurology, Xuanwu Hospital, Capital Medical University from April 2019 to August 2019, were chosen in our study; all patients were subjected to neuro-regulation of mismatched negativity (MMN) for 5 times in 2 weeks by EEG NF technique. By using the midlines of frontal zone (Fz), central zone (Cz) and peak zone (Pz) as training electrodes, auditory tones (1000 Hz as standard stimulus, individual hearing discrimination threshold as deviation stimulus) were used to induce MMN characteristics of event-related potential (ERP) via Oddball paradigm. SCD patients received visual disc stimulation feedback with dynamic neural signal activity. ERP waveforms and standard MMN characteristics (amplitude and latency) before and after training were used to evaluate the changes in neural activity of these patients; nine N-Back working memory tasks (three types×three gradients) and hearing discrimination ability tests were used in these patients to evaluate the improvement of cognitive competence.Results:ERP analysis showed that the MMN waveforms in SCD patients after training were obviously different as compared with those before training; their standard stimulus and deviant stimulus in the point-by-point paired t-test analysis were significant different ( P<0.05). The MMN amplitudes at the Fz, Cz and Pz electrodes in these patients after training were significantly higher than those before training ( P<0.05). The accuracy of auditory tone 3-Back task in SCD patients was statistically significant before and after training ( P<0.05). Conclusion:NF based on MMN can significantly improve the MMN amplitude and accuracy of auditory working memory task in patients with SCD, which might provide a potentially effective cognitive intervention method for patients with early AD and the elderly with normal memory decline.