Optimized scanning protocol for whole-brain perfusion by third generation dual-source computed tomography: A feasibility study / 第二军医大学学报

Objective To assess the influence of different time sampling modes on perfusion parameters and radiation dose of whole-brain computed tomography perfusion imaging (CTP), and to formulate an optimized scanning protocol for clinical diagnosis requirements. Methods Forty-seven consecutive patients, who underwent cerebral CTP scanning in our hospital between Nov. 2016 and Jun. 2017, were included in this study. Nineteen of them had acute ischemic stroke (AIS) and 28 had AIS symptoms, but no lesions were found by computed tomography or CTP. According to the time-attenuation curve, four scanning protocols were obtained: standard control group (group 1), sampling interval of 3 s (group 2), sampling interval of 3 s in pre-ascending and pro-descending period, and sampling interval of 1.5 s in the intermediate period (group 3), and smapling interval of 1.5 s between the peak of artery and vein and other sampling interval of 3 s (group 4). The perfusion parameters of all subjects were quantitatively measured. Subjective image quality was analyzed and radiation dose was calculated. Results In AIS and non-AIS groups, a total of 10 region of interests were placed in the ischemic area and contralateral brain parenchyma of each patient, and the total numbers of data points of perfusion parameters were 190 and 280, respectively. There were significant differences in blood flow, blood volume and mean transit time (MTT) between the AIS group and non-AIS group (all P0.01). However, inter-group analysis showed that there were no significant differences in the above perfusion parameters between group 3 and group 1 in both the AIS group and non-AIS group (all P0.05). Bland-Altman consistency analysis showed that group 3 and group 1 had good consistency of blood flow, blood volume and MTT in both the AIS group and non-AIS group. Compared with group 1 (standard control group), group 3 had better subjective score and lower radiation dose. Based on the sampling mode of group 3, 2 recommended scanning protocols were established and validated. The perfusion parameters of the 2 recommended scanning protocols were well correlated with those of group 1 in AIS patients and non-AIS patients (all P0.01). Conclusion The scanning protocol, in which sampling interval is 3 s in pre-ascending and pro-descending period and 1.5 s in intermediate period, is in good agreement with the standard scanning mode, and can reduce radiation dose. It may be a whole-brain CTP scanning protocol for the clinical settings.

Association mechanism of plasma protein convertase subtilisin/Kexin type 9 and calcific aortic valve disease / 中国免疫学杂志

Objective:To evaluate the association between the level of plasma proprotein convertase subtilisin/Kexin 9 (PCSK9) with incidence and severity of calcified aortic valve disease(CAVD).Methods:We prospectively recruited 120 CAVD patients with at least increased echo density and 40 control patients by transthoracic echocardiography.All patients were grouped by CT quantitative scoring system:aortic valve calcification (AVC)1,2,3 and 4.Calcium score of aortic valve were calculated.Total cholesterol (TC),low density lipoprotein cholesterol (LDL-C),high density lipoprotein cholesterol (HDL-C),triglyceride (TG), carrying lipoprotein A1 (apo A1) and apolipoprotein B (apo B),lipoprotein (a) {LP (a)} and hypersensitive C-reactive protein (hsCRP) were detected by biochemical analyzer.Plasma PCSK9 levels were measured by enzyme-linked immunosorbent assay.The re-lationship between AVC and plasma PCSK9 level,blood lipid,Apo A1,Apo B and hsCRP was analyzed.Results:The data indicated that Apo,B Lp(a) and LDL-C levels in AVC2-4 level was significantly higher than that of AVC1(P<0.05),while TG,APO,A1 HDL-C and hsCRP were not different significantly in the four groups.The levels of TC in group AVC3 and AVC4 were significantly higher than those in group AVC1(P<0.05).At the same time,the patients of grade AVC2-4 have higher level of plasma PCSK9 than patients of group AVC1(P<0.05).Correlation analysis was performed and aortic valve calcium score were significantly correlated with TC (r=0.248,P=0.026),LDL-C (r=0.222,P=0.048),Lp(a) (r=0.276,P=0.013),Apo A1(r=0.245,P=0.012),Apo B(r=0.212, P=0.019) and PCSK9(r=0.309,P=0.005) in all study subjects.PCSK9 was positively correlated with TC,LDL,LP (a),Apo A1, Apo,and no correlation with hsCRP (B).Conclusion:The level of PCSK9 in CAVD patients was significantly higher than that in control group.And there is an association of PCSK9 levels with the presence of CAVD,however.

Application of high-pitch dual-source CT with prospective ECG gated double scan mode in postoperative follow-up of coronary artery bypass grafting / 解放军医学杂志

Objective To evaluate the application of high-pitch dual-source CT with prospective ECG gated double scan mode (Double Flash) in postoperative follow-up of coronary artery bypass grafting (CABG).Methods Sixty-one patients undergone CABG and received coronary CT angiography (CCTA) from Apr.2012 to Dec.2014 were enrolled in present study.The patients were randomly divided into two groups according to scanning mode:group A (Double Flash mode,30 cases) and group B (retrospective ECG gated spiral mode,31cases).Evaluation parameters included volumetric CT dose index (CTDIvol) and effective radiation dose (ED).All the coronary segments were evaluated with double blind method by two independent observers according to the image quality (IQ) on 4-point scale (1:excellent to 4:non-diagnostic).Results There were 139 coronary artery bypass grafts in 2 groups.Group A had 69 grafts,including 25 artery grafts and 44 venous grafts.Group B had 70 grafts,including 29 grafts and 41 venous grafts.No significant difference was found in IQ.between the two groups for all coronary segments (1.22 ± 0.57 vs.1.21 ± 0.61,P=0.975).ED (4.34 ± 1.88 vs.17.07 ± 2.13mSv,P＜0.001) and CTDIvol (5.70 ± 2.36 vs.40.95 ± 3.12mGy,P＜0.001) were significantly lower in group A than in group B.Conclusion Double Flash spiral protocol of dual-source CCTA can acquire good image quality with reduced radiation dose during assessment of CABG patency,and might have potential value in the follow-up of CABG patency.

Effects of pericardial adipose tissue volume on coronary artery imaging / 国际生物医学工程杂志

Objective To measure the volume of pericardial adipose tissue (PAT) by a photons dual-source computed tomography (CT) (Somatom Definition Flash CT), and to analyze and evaluate the effects of pericardial adipose tissue volume on coronary artery imaging. Methods There were 123 patients with suspected coronary heart disease (CHD) who underwent CT coronary angiography (CTA) from February 2016 to August 2016 in our hospital were enrolled. According to the body mass index (BMI) of the patient, the tube current was set in the range of 100～400 mA and tube voltage was 100～120 kV. All the patients were divided into six groups from low to high based on the measured pericardial adipose tissue volumes. The coronary CTA imaging quality was evaluated by subjective scoring and objective comparison by calculating the signal-to-noise ratio and comparing the contrast-to-noise ratio. Statistical analysis was performed using Kmskal-Wallis rank sum test and Pearson correlation analysis. Results There was no significant difference in subjective scoring between different PAT groups (all P>0.05). There was no significant correlation between PAT content and signal-noise ratio and contrast noise ratio (P>0.05). Conclusions The pericardial adipose tissue volume has no significant effect on coronary artery CTA imaging.

Measurement of Opening and Closing Angles of Aortic Valve Prostheses In Vivo Using Dual-Source Computed Tomography: Comparison with Those of Manufacturers' in 10 Different Types

OBJECTIVE: The aims of this study were to compare opening and closing angles of normally functioning mechanical aortic valves measured on dual-source computed tomography (CT) with the manufacturers' values and to compare CT-measured opening angles according to valve function. MATERIALS AND METHODS: A total of 140 patients with 10 different types of mechanical aortic valves, who underwent dual-source cardiac CT, were included. Opening and closing angles were measured on CT images. Agreement between angles in normally functioning valves and the manufacturer values was assessed using the interclass coefficient and the Bland-Altman method. CT-measured opening angles were compared between normal functioning valves and suspected dysfunctioning valves. RESULTS: The CT-measured opening angles of normally functioning valves and manufacturers' values showed excellent agreement for seven valve types (intraclass coefficient [ICC], 0.977; 95% confidence interval [CI], 0.962-0.987). The mean differences in opening angles between the CT measurements and the manufacturers' values were 1.2degrees in seven types of valves, 11.0degrees in On-X valves, and 15.5degrees in ATS valves. The manufacturers' closing angles and those measured by CT showed excellent agreement for all valve types (ICC, 0.953; 95% CI, 0.920-0.972). Among valves with suspected dysfunction, those with limitation of motion (LOM) and an increased pressure gradient (PG) had smaller opening angles than those with LOM only (p < 0.05). CONCLUSION: Dual-source cardiac CT accurately measures opening and closing angles in most types of mechanical aortic valves, compared with the manufacturers' values. Opening angles on CT differ according to the type of valve dysfunction and a decreased opening angle may suggest an elevated PG.

Research progress on radiological differentially diagnosis of primary gastric lymphoma and infiltrating gastric carcinoma / 白血病·淋巴瘤

The primary gastric lymphoma and infiltrating gastric carcinoma have similar imaging performance.Therefore,it has been longely regarded as medical imaging difficulty to diagnostically differentiate between them.With the rapid development of various imaging techniques and imaging software,they have been widely used in differentiating between these two diseases.This article reviews the current status and progress of imaging studies in differentiation of primay gastric lymphoma and invasive gastric cancer.

Clinical value of dual-source CT in evaluating coronary artery disease / 中国基层医药

Objective To explore the clinical value of dual-source CT(DSCT) in the diagnosis of coronary artery disease by comparing the result of DSCT and coronary angiography(CAG).Methods From July 2009 to August 2010,36 patients with suspected coronary hear disease underwent both DSCT coronary angiography(DSCTCA) and selective GAG examination.The results of DSCT coronary angiography were compared with CAG which was the gold standard of diagnosing coronary disease.The sensitivity,specificity,positive and negative predictive value,and accuracy of DSCT were evaluated.Results 144 coronary arteries were well evaluated of 36 cases.The sensitivity,specificity,positive and negative predictive value,and accuracy of DSCT in the diagnosis of coronary hear disease were 100.00％,66.67％,93.75％,100.00％ and 97.20％ respectively by the number of patients;The McNemar test showed no significant difference between two methods( x2 =0.500,P ＞0.05 ) with a higher diagnosis concordance (Kapp =0.768,P ＜0.01).By detecting moderate to severe coronary artery stenosis,the sensitivity,specificity,positive and negative predictive value,accuracy were 95.24％,96.08％,90.91％,98.00％,95.83％,respectively.The McNemar test showed no significant difference between two methods(x2 =0.167,P ＞0.05) with a higher diagnosis concordance ( Kapp =0.899,P ＜ 0.01 ).Conclusion DSCT has a diagnostic accuracy of coronary heart disease close to that CAG,especially in evaluating patients with moderate to severe coronary artery stenosis,it has high compliance and consistency with CAG.DSCT is a noninvasive,safe and reliable radiographic method.

The Diagnostic Accuracy, Image Quality and Radiation Dose of 64-Slice Dual-Source CT in Daily Practice: a Single Institution's Experience

OBJECTIVE: We wanted to evaluate the image quality, diagnostic accuracy and radiation exposure of 64-slice dual-source CT (DSCT) coronary angiography according to the heart rate in symptomatic patients during daily clinical practice. MATERIALS AND METHODS: We performed a retrospective search for the DSCT coronary angiography reports of 729 consecutive symptomatic patients. For the 131 patients who underwent invasive coronary angiography, the image quality, the diagnostic performance (sensitivity, specificity, positive predictive value [PPV] and negative predictive value [NPV] for detecting significant stenosis > or = 50% diameter) and the radiation exposure were evaluated. These values were compared between the groups with differing heart rates (HR): mean HR or = 65 and HR variability (HRV) or = 15. RESULTS: Among the 729 patients, the CT reports showed no stenosis or insignificant coronary artery stenosis in 72%, significant stenosis in 26% and non-diagnostic in 2%. For the 131 patients who underwent invasive coronary angiography, 95% of the patients and 97% of the segments were evaluable, and the overall per-patient/per-segment sensitivity, the perpatient/per-segment specificity, the per-patient/per-segment PPV and the per-patient/per-segment NPV were 100%/90%, 71%/98%, 95%/88% and 100%/97%, respectively. The image quality was better in the HR or = 65 group (p = 0.001), but there was no difference in diagnostic performance between the two groups. The mean effective radiation doses were lower in the HR < 65 or HRV < 15 group (p < 0.0001): 5.5 versus 6.7 mSv for the mean HR groups and 5.3 versus 9.3 mSv for the HRV groups. CONCLUSION: Dual-source CT coronary angiography is a highly accurate modality in the clinical setting. Better image quality and a significant radiation reduction are being rendered in the lower HR group.

Progress of dual-source CT in cardiovascular diagnosis of children / 国际儿科学杂志

The dual source computed tomography (DSCT) is equipped with two corresponding detectors. DSCT scanners combine high spatial resolution with a considerably increased temporal resolution of 83 milliseconds to image the heart and vascular with reliably good image quality even without heart rate control. DSCT has proven its reliability in providing quality information for both function and morphology of the heart. Emergence of DSCT made CT coronary artery visualization easier and more robust. It has a brilliant practical future.

Dual source computed tomography in assessment of left atrial appendage volume and function: A comparison with MRI / 第二军医大学学报

Objective: To use dual source computed tomography (DSCT) for assessment of left atrial appendage volume and function, and to compare the results with those of cardiac cine MR (CMR). Methods: Sixty-two patients who received computed tomography angiography (CTA) during March 2008 to Feb. 2009 were included in the present study. The DSCT data sets (Somatom Definition, Siemens Medical Solutions, Forchheim, Germany) and FIESTA (fast imaging employing steady-state acquisition) cines (Signa Excite HD 3T, GE) of the vertical long axis covering the left atrium were obtained on the same day. The images were analyzed to obtain LAAVmax, LAAVmin and LAAEF using Vitrea Heart Function software and Report Card 2.0 software, for DSCT and CMR. Intermodality agreement between DSCT and CMR was tested using linear regression and t test. Interobserver variability was tested by Bland-Altman analyses. Results: The DSCT and CMR measurements of the left atrial appendage volume and function were not significantly different, and the measurements of the two methods were well correlated with each other, with the coefficient of LAAVmax, LAAVmin, and LAAEF (%) being 0.85, 0.86, and 0.76, respectively. However, compared with CMR, DSCT showed a tendency of overestimating LAAV max, LAAVmin and underestimating LAAEF. The interobserver variability of DSCT measurements was lower than that of CMR measurements. Conclusion: DSCT is accurate in assessing the left atrial appendage volume and function of patients referred for coronary CT imaging, and the results are reproducible.

Effect of Heart Rate and Coronary Calcification on the Diagnostic Accuracy of the Dual-Source CT Coronary Angiography in Patients with Suspected Coronary Artery Disease

OBJECTIVE: To evaluate the diagnostic accuracy of a dual-source computed tomography (DSCT) coronary angiography, with a particular focus on the effect of heart rate and calcifications. MATERIALS AND METHODS:One hundred and nine patients with suspected coronary disease were divided into 2 groups according to a mean heart rate ( or = 70 bpm) and into 3 groups according to the mean Agatston calcium scores ( 400). Next, the effect of heart rate and calcification on the accuracy of coronary artery stenosis detection was analyzed by using an invasive coronary angiography as a reference standard. Coronary segments of less than 1.5 mm in diameter in an American Heart Association (AHA) 15-segment model were independently assessed. RESULTS: The mean heart rate during the scan was 71.8 bpm, whereas the mean Agatston score was 226.5. Of the 1,588 segments examined, 1,533 (97%) were assessable. A total of 17 patients had calcium scores above 400 Agatston U, whereas 50 had heart rates > or = 70 bpm. Overall the sensitivity, specificity, positive predictive values (PPV) and negative predictive values (NPV) for significant stenoses were: 95%, 91%, 65%, and 99% (by segment), respectively and 97%, 90%, 81%, and 91% (by artery), respectively (n = 475). Heart rate showed no significant impact on lesion detection; however, vessel calcification did show a significant impact on accuracy of assessment for coronary segments. The specificity, PPV and accuracy were 96%, 80%, and 96% (by segment), respectively for an Agatston score less than 100% and 99%, 96% and 98% (by artery). For an Agatston score of greater to or equal to 400 the specificity, PPV and accuracy were reduced to 79%, 55%, and 83% (by segment), respectively and to 79%, 69%, and 85% (by artery), respectively. CONCLUSION: The DSCT provides a high rate of accuracy for the detection of significant coronary artery disease, even in patients with high heart rates and evidence of coronary calcification. However, patients with severe coronary calcification (> 400 U) remain a challenge to diagnose.

Initial assessment of the reliability and value of dual-source computed tomography in the evaluation of coronary artery disease / 医学研究生学报

Objective:The aim of this study was to assess the diagnostic accuracy of dual-source computed tomography(DSCT) in the evaluation of coronary artery disease(CAD).Methods:Fifty-two patients(44 male,8 female,mean age 70.59) with a high pre-test probability of CAD underwent DSCT coronary angiography and selective coronary angiography(SCA).Two physicians independently assessed the images of all coronary segments.Results:The overall sensitivity,specificity,positive and negative predictive value for evaluating CAD were 92.31%,99.82%,90.57%,and 99.32%,respectively.Conclusion:The result indicates that DSCT coronary angiography provides high diagnostic accuracy for assessment of CAD.And it is a better choice for CAD evaluation.

Principle of 64-Slice Dual-Source Computed Tomography / 医疗卫生装备

The construction of 64-slice-dual-source computed tomography(DSCT) is introduced.Its imaging principle and clinical application are put forward.DSCT has special advantages in diagnosing coronary stricture.The principles of DSCT and energy subtraction imaging are expatiated in detail.DSCT has great value in clinical research and application.