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The competency-based medical education has formed a global trend, and puts forward a greater challenge for educational design of resident training. The traditional curriculum cannot meet the goal of competency-based education as the curriculum design is lack of theoretical support. Curriculum design is the core of training content, and serves as a significant contributing factor of training outcome. Based on the six-step approach curriculum design, the theory and practice are integrated to form a curriculum design based on theoretical guidance. Through feedback evaluation, the current curriculum design is continuously improved in order to achieve a higher competency-based training quality. With the 5-year experiences and practice, preliminary reform demonstrates effectiveness. The current study hopes to share the teaching reform experiences of residency training base and provide references for colleagues of medical education.
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Objective:To explore application value of improving quality of the low dose pancreatic CT images by using deep learning reconstruction (DLR).Methods:From August to December 2020, 68 patients who underwent contrast-enhanced pancreatic CT were prospectively collected in Peking Union Medical College Hospital. All patients were randomly divided into routine dose group (34 patients, with tube voltage of 120 kV) and low dose group (34 patients, with tube voltage of 100 kV). All patients underwent non-contrast, arterial phase, parenchymal phase and delay phase scans. The four-phase images of low dose group were reconstructed by using filtered back projection (FBP), hybrid iterative reconstruction (AIDR) and DLR which were marked with LD-FBP, LD-AIDR and LD-DLR, respectively. The four-phase images of routine dose group were reconstructed by using AIDR algorithm which were marked with RD-AIDR. The CT value, image noise (SD), signal to noise ratio (SNR) and contrast to noise ratio (CNR) of pancreas were measured. The ANOVA test was performed in comparison with objective parameters of different reconstruction algorithms, and LSD test was performed in pairwise comparison. The subjective image scores were obtained and were compared using Kruskal-Wallis test.Results:CT value, SD, SNR and CNR of non-contrast, arterial phase, parenchymal phase and delay phase had significant difference among different reconstruction images of routine dose group and low dose group (all P<0.05). The CT value of LD-FBP, LD-AIDR, and LD-DLR images were significantly higher than those of RD-AIDR images in parenchymal phase and delay phase (all P<0.05). There were statistically significant differences in each pairwise comparison of SD and SNR of four phase images (all P<0.05). There were statistically significant differences of CNR among LD-FBP, LD-DLR and RD-AIDR in four phase images (all P<0.05). The CNR of RD-AIDR was better than that of LD-FBP, and CNR of LD-DLR was better than that of RD-AIDR. DLR algorithm improved the SD, SNR and CNR of four phases of pancreatic images. The improvement of SNR was more significant after contrast enhancement, and the improvement of CNR was more significant in the non-contrast and delay phases. Subjective image scores of different reconstruction images were statistically different in four phase images (all P<0.001). Overall image scores of LD-DLR and RD-AIDR had no significant differences in four phase ( Z value of four phases were 1.00, 2.24, 0.45 and 1.34, respectively; P value of four phases were 0.317, 0.025, 0.655 and 0.180, respectively). Conclusion:The DLR technology can decrease radiation dose of pancreatic CT, improve image quality and satisfy diagnostic requirement. The DLR technology can also reduce image noise, improve the SNR and CNR in low dose contrast-enhanced pancreatic CT.
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Pancreatic neuroendocrine neoplasms (pNENs) are highly heterogeneous, and the management of pNENs patients can be intractable. To address this challenge, an expert committee was established on behalf of the Chinese Pancreatic Surgery Association, Chinese Society of Surgery, Chinese Medical Association, which consisted of surgical oncologists, gastroenterologists, medical oncologists, endocrinologists, radiologists, pathologists, and nuclear medicine specialists. By reviewing the important issues regarding the diagnosis and treatment of pNENs, the committee concluded evidence-based statements and recommendations in this article, in order to further improve the management of pNENs patients in China.
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Objective:To investigate the correlation between amide proton transfer-weighted (APTw) values and Ki-67 labeling index of cervical squamous cell carcinoma.Methods:From October 2017 to December 2018, 24 patients with cervical squamous cell carcinoma [International Federation of Gynecology and Obstetrics (FIGO) stage Ⅰ-Ⅲ] were prospectively enrolled in Peking Union Medical College Hospital and underwent pelvic morphological MRI on a 3.0 T MR scanner, including three-dimensional turbo-spin-echo APTw imaging and DWI. The maximum diameters of the lesions, APTw values and ADC values on the slice with the maximum diameter of the lesion were independently measured by two radiologists. The ICC was computed to evaluate the inter-observer consistency. Ki-67 immunohistochemical expression status was assessed by one pathologist. The Pearson correlation analysis was performed between the APTw values, maximum diameters, ADC values and Ki-67 labeling index.Results:The APTw values of cervical squamous cell carcinoma were (2.9±0.5)%. Inter-observer ICC was 0.972 (95%CI 0.937-0.988). The APTw values were positively moderately correlated with Ki-67 labeling index [(61.9±18.7)%, r=0.532, P=0.008]. The maximum diameters of the lesions were (28.7±10.6) mm. The mean ADC values were (0.998±0.217)×10 -3 mm 2/s. No correlations were found between maximum diameters, ADC values and Ki-67 labeling index ( r=0.038, P=0.859; r=0.238, P=0.263). Conclusion:APTw values can partially reveal the proliferation status of cervical squamous cell carcinoma.
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Objective@#To explore the application value of 3.0 T MultiVane XD (MVXD) technique in female patients with uterine adenomyosis and fibroids.@*Methods@#Patients diagnosed with uterine fibroids with ultrasound and suspected of adenomyosis were involved prospectively from March to May 2018, 3.0 T pelvic MRI examinations were performed during peri-ovulatory period. Axialconventional turbo spin echo (TSE) T2WI, axial MVXD T2WI, sagittal conventional TSE T2WI and MVXD sagittal T2WI were acquired. Two observers rated those 4 series in the aspects of sharpness of uterine border, motion artifacts, identification capability of lesions, confidence of diagnosis and overall image quality. Cohen Kappa analysis was used to evaluate the consistency of scores between 2 observers. Scores of TSE T2WI and MVXD T2WI qualities were compared using Wilcoxon matched-pairs signed-ranks test.@*Results@#Twenty patients were enrolled. Axial conventional TSE T2WI, axial MVXD T2WI were aquired on all of them. Sagittal conventional TSE T2WI, sagittal MVXD T2WI were aquired on 19 among them. Nine patients had only obvious adenomyosis, 6 had only uterinefibroids, and 5 had adenomyosis and uterine fibroids. Compared to conventional TSE technique, scores of two observers in the sharpness of uterine border, motion artifacts, and overall image quality is higher by MVXD with significant difference (P<0.05). The Kappa values for image quality scores of two observers ranged from 0.615 to 0.971, the agreement was good or very good.@*Conclusion@#Applying MVXD T2WI technique to patients with uterine fibroids and adenomyosiscould improve image quality, without sacrificing the ability to recognize and diagnose lesions, compared to conventional TSE T2WI technique.
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Objective:To explore the application value of 3.0 T MultiVane XD (MVXD) technique in female patients with uterine adenomyosis and fibroids.Methods:Patients diagnosed with uterine fibroids with ultrasound and suspected of adenomyosis were involved prospectively from March to May 2018, 3.0 T pelvic MRI examinations were performed during peri-ovulatory period. Axialconventional turbo spin echo (TSE) T 2WI, axial MVXD T 2WI, sagittal conventional TSE T 2WI and MVXD sagittal T 2WI were acquired. Two observers rated those 4 series in the aspects of sharpness of uterine border, motion artifacts, identification capability of lesions, confidence of diagnosis and overall image quality. Cohen Kappa analysis was used to evaluate the consistency of scores between 2 observers. Scores of TSE T 2WI and MVXD T 2WI qualities were compared using Wilcoxon matched-pairs signed-ranks test. Results:Twenty patients were enrolled. Axial conventional TSE T 2WI, axial MVXD T 2WI were aquired on all of them. Sagittal conventional TSE T 2WI, sagittal MVXD T 2WI were aquired on 19 among them. Nine patients had only obvious adenomyosis, 6 had only uterinefibroids, and 5 had adenomyosis and uterine fibroids. Compared to conventional TSE technique, scores of two observers in the sharpness of uterine border, motion artifacts, and overall image quality is higher by MVXD with significant difference ( P<0.05). The Kappa values for image quality scores of two observers ranged from 0.615 to 0.971, the agreement was good or very good. Conclusion:Applying MVXD T 2WI technique to patients with uterine fibroids and adenomyosiscould improve image quality, without sacrificing the ability to recognize and diagnose lesions, compared to conventional TSE T 2WI technique.
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This is a complicated and difficult case. The onset symptom of a 62-year-old male was recurrent intestinal obstruction. Ileocecal and ileocolic operation was done twice. Massive gastrointestinal bleeding occurred due to giant fistula of descending duodenum, which connected to ileocolic anastomosis. After consultation by multidisciplinary team, jejunal-feeding tube was placed to provide enteral nutrition. With general condition improving, duodenal fistula repair and involved bowel resection were performed. Postoperative pathology confirmed Crohn's disease. The patient was treated with thalidomide and recovered well during follow-up.
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Objective To analyze the imaging data of patients with complete clinical remission ( cCR ) and postoperative pathological complete remission ( pCR ) after concurrent chemoradiotherapy, aiming to evaluate the values of MRI and rectal ultrasound in predicting pCR. Methods Clinical data of 42 patients with locally advanced rectal cancer treated with concurrent chemoradiotherapy combined with operation were retrospectively analyzed. The magnetic resonance imaging (MRI), endoscopic ultrasound (EUS) and pathological data were statistically compared between patients with cCR and pCR. Results After concurrent chemoradiotherapy,12 patients obtained cCR and 7 patients achieved pCR.The consistency rate of cCR between MRI and EUS was 3/12(25％), and 4/12(33％) for pCR.The consistency rate of pCR of MRI combined with EUS was 5/12 ( 42％) . Conclusion Rectal ultrasound combined with MRI cannot fully predict pCR. More accurate detection approach remains to be explored to evaluate the clinical outcomes of watch-and-wait patients.
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Objective To analyze the clinical characteristics of IgG4-related disease (IgG4-RD)so as to improve the understanding of IgG4-RD in China.Methods IgG4-RD patients were recruited from Peking Union Medical College Hospital between January 2011 and January 2016.All patients were followedup for more than 6 months.The demographic characteristics,symptoms,organ involvements,laboratory examinations and treatment efficacy were evaluated and analyzed.Results A total of 346 patients were finally enrolled,including 230 males (66.5％) and 116 females (33.5％).The mean age of disease onset was (53.8 ± 14.2) years old.The mostly common involved organs were lymph nodes (56.4％) and submandibular glands (52.6％).Other affected organs and manifestations included:swelling of the lacrimal glands (46.5％),autoimmune pancreatitis (38.4％),pulmonary involvement (28.0％),sclerosing cholangitis (25.4％),naso-sinusitis (23.4％),parotid gland swelling (21.7％),retroperitoneal fibrosis (19.9％),large arteries involvement (9.5％),kidney involvement (obstructive nephropathy caused by retroperitoneal fibrosis was excluded) (6.9％),skin lesions (6.4％).Rare features consisted of thyroid glands,pituitary glands,gastrointestinal tract,pachymeningitis,pericardium,sclerosing mediastinitis and orchitis.The majority of patients had multi-organ involvement,such as 74.3％ patients with 3 and more,18.2％ and 7.5％ patients with 2 and single organ involvement respectively.The average IgG4-RD responder index (IgG4-RD RI) was 13.21 ±5.70.History of allergy was found in 172 (49.7％) patients.As to the laboratory tests,elevated serum IgG4 levels were confirmed in 285 (94.1％) patients,which was positively correlated with IgG4-RD RI.There were 33.5％ patients receiving monotherapy of glucocorticoid,52.6％ treated with glucocorticoids combined with immunosuppressive agents,4.9％ patients with immunosuppressant only,and 9.0％ patients with mild disease not receiving medication.The majority (336,97.1％) patients improved the above regimens.Conclusion IgG4-RD is a systemic fibro-inflammatory disease with multiple organ involvement.The mostly common involved organs include lymph node,submandibular glands,and pancreas.Glucocorticoids and immunosuppressive agents were effective for IgG4-RD.
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Objective To investigate the feasibility of using CT texture analysis to differentiate among lipid-poor adrenal adenoma,pheochromocytoma and adrenal metastases.Methods 66 lipid-poor adrenal adenoma,98 pheochromocytoma and 101 adrenal metastases lesions were analyzed retrospectively.All the patients had abdominal non-enhanced CT and adrenal enhanced CT scans.We used TexRAD software to analyze the textural features of CT images and compared the differences in each texture parameter among three adrenal lesions.Results On non-enhanced CT images,there were significant differences in Mean and Kurtosis at all the texture scales(SSF 0-6) among the three types of adrenal lesions (P<0.05),as well as SD at fine and coarse texture scale (SSF 2,6)(P<0.05).Entropy (SSF 0-3, 5-6) and MPP (SSF 0-2, 4-6) were significantly lower in lipid-poor adrenal adenoma and adrenal metastases than that in pheochromocytoma (P<0.05).There were significant differences in Skewness (SSF 0-3) among three types of lesions, which was lowest in pheochromocytoma and highest in adrenal metastases.On enhanced CT images, Mean, SD, Entrophy and MPP showed significantly differences among the three types of adrenal lesions at all the texture scales (SSF 0-6) (P<0.05), which were all highest in pheochromocytoma and lowest in adrenal metastases.Skewness (SSF 0) and Kurtosis (SSF 0, 2) were significantly lower in adrenal metastases than that in lipid-poor adrenal adenoma and pheochromocytoma (P<0.05).Conclusion There are significant differences in CT texture analysis parameters among lipid-poor adrenal adenoma,pheochromocytoma and adrenal metastases.CT texture analysis has potential clinical application values in differentiating these three adrenal lesions.
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Objective To evaluate the effects of infective necrosis (IN) on prognosis in moderately severe or severe acute pancreatitis (AP).Methods According to the revision of Atlanta classification,from January 2001 to January 2015,admitted patients with moderately severe or severe AP were retrospectively analyzed.According to whether with the presence of persistent organ failure (POF) and / or IN,the patients were divided into four groups:group one with weither IN nor POF,group two with IN but without POF,group three with POF but without IN,group four with both IN and POF.The differences in disease severity and prognosis among groups were compared.Logistic regression and Cox proportional hazard regression model were used to analyze the effect of IN on prognosis.Results A total of 375 moderately severe or severe AP patients were enrolled.There were 211,43,90 and 31 patients in group one,two,three and four,respectively.A total of 121 (32.3％) patients with POF,74 (19.7％) patients with IN,and death in 63 (16.8％) patients.The mortality rate in patients with IN was 32.4％ (24/74),and which was 13.0％(39/301) in patients without IN.The mortality rates of group one,two,three and four were 1.9％(4/211),11.6％(5/43),38.9％(35/90) and 61.3％(19/31),respectively;mortality rate was in a trend of increasing,and the difference was statistically significant (x2 =109.672,P＜0.01).Both IN (OR=8.24,95％CI2.09 to 32.46) andPOF (OR=8.31,95％ CI2.48 to 27.87)were independent risk factors of mortality of AP patients (both P＜0.01).Both IN (OR=2.04,95 ％CI 1.19 to 3.48,0.002) and POF (OR=5.25,95％CI 2.36 to 11.65) also were independent risk factors of shortened survival time of AP patients (both P＜0.01).Conclusions IN is an independent risk factor of disease severity and poor prognosis in AP.The prognosis is the worst in AP patients with both POF and IN.
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Objective To compare the performance of the revision of Atlanta classification (RAC) and determinant-based classification (DBC) in acute pancreatitis. Methods Consecutive patients with acute pancreatitis admitted to a single center from January 2001 to January 2015 were retrospectively analyzed. Patients were classified into mild, moderately severe and severe categories based on RAC and were simultaneously classified into mild, moderate, severe and critical grades according to DBC. Disease severity and clinical outcomes were compared between subgroups. The receiver operating curve (ROC) was used to compare the utility of RAC and DBC by calculating the area under curve (AUC). Results Among 1120 patients enrolled, organ failure occurred in 343 patients (30.6%) and infected necrosis in 74 patients (6.6%). A total of 63 patients (5.6%) died. Statistically significant difference of disease severity and outcomes was observed between all the subgroups in RAC and DBC (P<0.001). The category of critical acute pancreatitis (with both persistent organ failure and infected necrosis) had the most severe clinical course and the highest mortality (19/31, 61.3%). DBC had a larger AUC (0.73, 95%CI 0.69-0.78) than RAC (0.68, 95%CI 0.65-0.73) in classifying ICU admissions (P=0.031), but both were similar in predicting mortality(P=0.372) and prolonged ICU stay (P=0.266). Conclusions DBC and RAC perform comparably well in categorizing patients with acute pancreatitis regarding disease severity and clinical outcome. DBC is slightly better than RAC in predicting prolonged hospital stay. Persistent organ failure and infected necrosis are risk factors for poor prognosis and presence of both is associated with the most dismal outcome.
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Objective To investigate the image quality of head and neck CT angiography (CTA)using the third-generation dual-source CT combined with 70 kV tube voltage and 20-25 ml contrast medium (CM),and evaluate the effects of venous artifacts arising from the CM on the ipsilateral side of injection. Methods Totally 40 consecutive patients with suspected vascular diseases and body weight lower than 75 kg prospectively underwent head and neck CTA examination using the third-generation dual-source CT. CTA was performed with a third-generation dual-source CT system. Patients were randomly divived into 70 kV group (n=20)and 100 kV group (n=20). The 70 kV group used 20-25 ml CM and advanced modeled iterative reconstruction technique,and the 100 kV group used 40 ml CM and filtered back projection. Venous artifacts and CM residues were evaluated by a 3-point scale (1=excellent,3=poor),respectively. Results The effective dose of 70 kV group decreased 58% compared to 100 kV group (t=-18.14,P<0.001).In the 70 kV group,16 patients (80.0%)presented with venous artifacts and six of them (37.5%,6/16)affected the adjacent arteries. In the 100 kV group,19 patients (95.0%)presented with venous artifacts,and seven of them (36.8%,7/19)affected the adjacent arteries (Z=-0.878,P=0.380). In the 70 kV group,13 patients (65.0%)presented with obvious CM residues and two of them (15.3%,2/13)prolonged into the superior vena cava (SVC). In the 100 kV group,19 patients(95.0%)presented with obvious CM residues,and thirteen of them(68.4%,13/19)prolonged into the SVC (Z=-3.654,P<0.001). Conclusion Compared with the 100 kV,the third-generation dual-source CT for head and neck CTA,combined with 70 kV and 20-25 ml CM,can remarkably decrease the radiation dose,along with reduced CM residues and comparable venous artifacts.
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Humans , Artifacts , Body Weight , Computed Tomography Angiography , Methods , Contrast Media , Head , Diagnostic Imaging , Neck , Diagnostic Imaging , Radiation Dosage , Radiographic Image Interpretation, Computer-AssistedABSTRACT
Objective To evaluate the radiation dose and image quality of the third-generation dual-source CT using automated tube voltage adaptation (CARE kV) in temporal bone scanning in pediatric patients with hearing impairment. Methods Totally 27 children with hearing impairment less than 18 years old were randomly divided into two groups:Group A (n=14),examined with CARE kV (reference with 100 kV and 214 mA)and sinogram-affirmed iterative reconstruction;and Group B (n=13),examined with CARE kV (reference with 100 kV and 171 mA)and advanced modeled iterative reconstruction. The scan range was from eyebrow to the end of the mastoid process. CT values and image noise were measured.The signal to noise ratio (SNR)was calculated. Subjective image quality was assessed by two radiologists and later in a consensus reading. Results There was no significant difference in CT value,image noise,and SNR between these two groups (all P>0.05). Also,the subjective scores of the 10 anatomical structures showed no significant difference (all P>0.05). The CT dose index volume and dose-length product were (11.62+1.92)mGy and (106.92+37.48)mGy·cm,respectively,in group B and (21.28+2.19)mGy (t=12.15,P<0.001)and (229.65+56.26)mGy·cm (t=6.62,P<0.001)in group A,decreased by 45% and 53%. Conclusion Compared with the second-generation dual-source CT,the third-generation dual-source CT for the scanning of temporal bone with CARE kV can ensure image quality and reduce radiation dose.
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Child , Humans , Hearing Loss , Diagnosis , Radiation Dosage , Radiographic Image Interpretation, Computer-Assisted , Signal-To-Noise Ratio , Temporal Bone , Diagnostic Imaging , Tomography, X-Ray Computed , MethodsABSTRACT
Objective To prospectively investigate the radiation dose and image quality of pediatric chest CT using Sn100 kV on a third-generation dual-source CT (DSCT)in comparison to standard 100 kV chest CT. Methods From December 12,2015 to June 30,2016,45 consecutive pediatric patients referred for non-contrast chest CT scan in Peking Union Medical College Hospital were prospectively enrolled as study group. They were examined at 100 kV with a dedicated tin filter on a third-generation DSCT. These patients were retrospectively matched with 45 patients who were examined on a second-generation DSCT at 100 kV without tin filter. The radiation dose as well as the lung and mediastinal window image quality(IQ)of the two groups were compared and analyzed statistically. IQ was evaluated using a five-point scale (1=unevaluable,5=excellent). Differences of radiation dose and noise between the two groups were determined with variance analysis and t test,IQ with Mann-Whitney U test,and the consistency of diagnosis with Kappa test. Results The average CT dose index volume of the study group was (0.24±0.11)mGy,which was decreased by 92% compared with the control group [(3.10+1.18)mGy] (t=16.287,P=0.000). Mean dose-length product and mean effective dose for study group were significantly lower than those of control group [(7.13±4.72)mGy·cm vs. (84.78±46.78)mGy·cm,t=11.077,P=0.000;(0.11±0.06)mSv vs.(1.23±0.61)mSv,t=12.334,P=0.000]. There was no significant difference between the two groups in terms of image noise (t=-0.003,P=0.397)and contrast to noise ratio (t=0.545,P=0.488). There was no significant difference between the two groups in lung window IQ (doctor 1:U=796.000,P=0.055;doctor 2:U=889.500,P=0.277),while significant difference was seen concerning of the mediastinal window IQ (doctor 1:U=305.000,P=0.000;doctor 2:U=276.500,P=0.000). Referring to the lung window,the median IQ for the study group and control group was 4 (3-5)and 4 (3-5),respectively. All imaging findings had acceptable IQ. The breath motion artifacts (χ=13.846,P=0.001)and heart beat artifacts (χ=53.519,P=0.000)of the study group were significantly lower than those of the control group. Conclusion Compared with standard 100 kV chest CT,the use of tin-filtered Sn100 kV on a third-generation DSCT provided 92% dose reduction in pediatric chest CT examinations while maintaining diagnostically acceptable lung window images.
Subject(s)
Child , Humans , Artifacts , Feasibility Studies , Lung , Diagnostic Imaging , Radiation Dosage , Radiographic Image Interpretation, Computer-Assisted , Retrospective Studies , Thorax , Diagnostic Imaging , Tomography, X-Ray Computed , MethodsABSTRACT
Objective To evaluate the application of automated tube potential selection technique in high-pitch dual-source CT aortic angiography on a third-generation dual-source CT scanner. Methods Whole aorta angiography were indiated in 59 patients,who were divided into 2 groups using a simple random method:in group 1 there were 31 patients who underwent the examination with automated tube potential selection using a vascular setting with a preferred image quality of 288 mA/100 kV;in group 2 there were 28 patients who underwent the examination with a tube voltage of 100 kV and automated tube current modulation using a reference tube current of 288 mA. Both groups were scanned on a third generation dual-source CT device operated in dual-source high-pitch ECG-gating mode with a pitch of 3.0,collimation of 2×192×0.6 mm,and a rotation time of 0.25 s. Iterative reconstruction algorithm was used. For group 1,the volume and flow of contrast medium and chasing saline were adapted to the tube voltage. For group 2,a contrast material bolus of 45 ml with a flow of 4.5 ml/s followed by a 50 ml saline chaser at 5 ml/s was used. CTA scan was automatically started using a bolus tracking technique at the level of the original part of aorta after a trigger threshold of 100 HU was reached. The start delay was set to 6 s in both groups. Effective dose (ED),signal to noise ratio (SNR),contrast to noise ratio (CNR),and subjective diagnostic quality of both groups were evaluated. Results The mean ED were 21.3% lower (t=-3.099,P=0.000) in group 1 [(2.48±0.80) mSv] than in group 2 [(3.15±0.86) mSv]. Two groups showed no significant difference in attenuation,SD,SNR,or CNR at all evaluational parts of aorta (ascending aorta,aortic arch,diaphragmatic aorta,or iliac bifurcation)(all P>0.05). There was no significant difference in subjective diagnostic quality values of two groups [(1.41±0.50) scores vs. (1.39±0.50) scores;W=828.5,P=0.837]. Conclusion Compared with automated tube current modulation,the automated tube potential selection technique in aorta CT angiography on a third-generation dual-source CT can dramatically reduce radiation dose without affecting image quality.
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Humans , Algorithms , Aorta , Diagnostic Imaging , Computed Tomography Angiography , Methods , Radiation Dosage , Radiographic Image Interpretation, Computer-Assisted , Signal-To-Noise RatioABSTRACT
Objective To evaluate the value of third-generation dual-source CT scanner in application of high-pitch aorta CT angiography(CTA). Methods Totally 59 patients clinically indicated for whole aorta angiography were divided into 2 groups using a simple random method:in group 1 there were 28 patients who underwent the examination on a third-generation dual-source CT device,with a collimation of 2×192×0.6 mm and a rotation time of 0.25 s;in group 2 there were 31 patients who underwent the examination on a second generation dual-source CT device,with a collimation of 2×128×0.6 mm and a rotation time of 0.28 s. Both groups were given the examination operated in dual-source high-pitch ECG-gating mode with a pitch of 3.0,a tube voltage of 100 kV,and automated tube current modulation using a reference tube current of 288 mA. A contrast material bolus of 45 ml with a flow of 4.5 ml/s followed by a 50 ml saline chaser in 5.0 ml/s was used. CTA scan was automatically started using a bolus tracking technique at the level of the original part of aorta after a trigger threshold of 100 HU was reached. The start delay was set to 6 s in both groups. Effective dose(ED),signal to noise ratio (SNR),contrast to noise ratio (CNR),and subjective diagnostic quality of both groups were evaluated. Results The mean ED were 19.44% lower (t=-3.989,P=0.000) in group 1 [(3.15±0.86)mSv] than in group 2 [(3.91±0.60)mSv]. These two groups showed no significant differences in SNR or CNR (all P >0.05). The subjective diagnostic quality values also showed no significant difference between two groups [(1.39±0.50)scores vs. (1.45±0.51)scores;W=814.5,P=0.651].Conclusion Compared with the second-generation dual-source CT scanner,the third-generation dual-source CT scanner in whole aorta CTA can remarkably reduce the radiation dose without affecting image quality.
Subject(s)
Humans , Aorta , Diagnostic Imaging , Computed Tomography Angiography , Methods , Radiation Dosage , Retrospective Studies , Signal-To-Noise RatioABSTRACT
Objective To compare measurements of dual-energy CT iodine map parameters and liver perfusion CT parameters in patients with focal liver lesions using a third-generation dual-source CT scanner. Methods Between November 2015 and August 2016,33 patients with non-cystic focal lesions of liver were enrolled in this study. CT examinations were performed with a third-generation dual-source CT. The study CT protocol included a perfusion CT and dual-energy arterial and portal venous scans,with a time interval of 15 minutes. Iodine attenuation was measured at five region of interests including areas of high,medium,and low density within the lesion,as well as right and left liver parenchyma from the iodine map,while arterial liver perfusion (ALP),portal venous liver perfusion (PVP),and hepatic perfusion index (HPI) at the same location were measured from perfusion CT. The Pearson product-moment correlation coefficient was used to evaluate the relationship between iodine attenuation and perfusion parameters. Results The iodine attenuation at arterial phase showed significant intra-individual correlation with ALP (r=0.812,95% CI=0.728-0.885,P<0.001)and PVP (r=-0.209,95% CI=-0.323--0.073,P=0.007),but not significantly correlated with HPI (r=0.058,95% CI=0.046-0.498,P=0.461). The iodine attenuation at portal venous phase showed significant correlation with PVP (r=0.214,95% CI=0.072-0.361,P=0.005) but not with HPI(r=0.036,95% CI=-0.002-0.242,P=0.649). The mean effective dose of arterial phase and portal venous phase of dual-energy CT together [(3.53±1.17)mSv] was significantly lower than that of the perfusion CT [(14.53±0.45)mSv](t=25.212,P<0.001). Conclusion Iodine attenuation from arterial phase of dual energy CT demonstrates significant correlation with ALP and PVP,and iodine attenuation from portal venous phase demonstrates significant correlation with PVP.
Subject(s)
Humans , Contrast Media , Iodine , Liver , Diagnostic Imaging , Pathology , Perfusion , Portal Vein , Tomography, X-Ray Computed , MethodsABSTRACT
Objective To characterize the CT perfusion parameters of focal pancreatic lesions including pancreatic cancers (PACs) and pancreatic neuroendocrine tumors (pNETs),estimate the confirmity and fungibility of parameters obtained from Deconvolution and Maximum slope+Patlak.Methods From December 2015 to November 2016,22 patients with PACs and 22 patients with pNETs(37 lesions confirmed by surgery and biopsy)underwent preoperative whole-pancreas CT perfusion in our center. The volume perfusion CT of the entire pancreas was performed at 80 kV and 100 mA,using 28 consecutive volume measurements and intravenous injection of 45 ml of iodinated contrast and saline at a flow rate of 5 ml/s. One experienced radiologists measured and recorded the CT perfusion parameters on Siemens post-processing workstation using two mathematical methods:Maximum slope+Patlak analysis versus Deconvolution method.ResultsWilcoxon matched-pairs test revealed significant difference between both pairs of the perfusion measurements by the two methods,PACs(BFM vs. BFD,Z=-3.263,P=0.001;BVD vs. BVP,Z=-3.978,P=0.000); pNETs(BFM vs. BFD,Z=-5.212,P=0.000;BVD vs. BVP,Z=-2.633,P=0.008). Spearman's correlation coefficient showed both pairs of perfusion measurements significantly correlated with each other in PACs (BFM vs. BFD,r=0.845,P=0.000;BVD vs. BVP,r=0.964,P=0.000) and pNETs(BFM vs. BFD,r=0.759,P=0.000),BVD vs. BVP,r=0.683,P=0.000). Geometric mean BFM/BFD ratio in PACs was 0.77 (range:0.61-0.99),while geometric mean BVD/BVP ratio was 1.42 (range:1.13-1.79),within 95% limits of agreement. Geometric mean BFM/BFD ratio in pNETs was 0.66 (range:0.51-0.86),while geometric mean BVD/BVP ratio was 1.15 (range:0.88-1.50),within 95% limits of agreement. Conclusion sSignificantly different CT perfusion values of blood flow and blood volume were obtained by Deconvolution-based and Maximum slope+Patlak-based algorithms in the pNETs and PACs. They correlated significantly with each other. Two perfusion-measuring algorithms are interchangeable because the ranges of the conversion factors are narrow.
Subject(s)
Humans , Algorithms , Blood Volume , Contrast Media , Pancreas , Diagnostic Imaging , Pathology , Pancreatic Neoplasms , Diagnostic Imaging , Reproducibility of Results , Sensitivity and Specificity , Tomography, X-Ray Computed , MethodsABSTRACT
Objective To evaluate the image quality and radiation exposure in multidetector computed tomography (MDCT) with automated topogram-based tube potential selection,compared to fixed tube potential,in patients with solid pancreatic lesions. Methods The preoperative pancreatic dual-source CT images of 113 patients who were confirmed as solid pancreatic lesions by postoperative pathology in the Peking Union Medical College Hospital from January 2014 to August 2016 were retrospectively analyzed.Among them,53 patients were examined on fixed tube potential at 120 kV,and tube current was automatically modulated (group 1). Sixty patients underwent topogram-based automatic tube potential selection (Tube voltage step:90,100 kV) and automated mA modulation (group 2). Two experienced radiologists measured the body sizes,assessed subjective and objective image quality of arterial phase and portal phase,and recorded radiation parameters including CT dose index volume (CTDI) and dose-length product (DLP). Results Of 60 patients in group 2,45 patients were scaned at 90 kV,15 patients were scaned at 100 kV.The average body diameter [(287±24) mm] in 90 kV group was significantly lower than that [(328±22) mm] in 100 kV group(t=0.731,P=0.0008). The mean CTDI[(3.9±1.0) mGy] in group 2 was significantly lower than in group 1 [(9.0±1.9) mGy],reduced by 56.7% (t=17.5,P=0.0003). The average DLP [(109±38) mGy·cm] in group 2 was significantly lower than that in group 1 [(276±83) mGy·cm],reduced by 60.5% (t=14.0,P=0.0007). In group 2,the standard deviations of images background noise in arterial and portal phase were (6.4±0.9) and (6.4±1.0)HU,respectively,which were significantly higher than those in group 1 [(5.6±1.4)HU,t=-3.757,P=0.0003;(5.5±1.4)HU,t=-3.828,P=0.0006]. In group 2,the signal to noise ratios of pancreatic lesions, abdominal aorta in arterial phase and pancreatic lesions, the portal vein in portal phase were 18.8±9.3,76.0±19.3 and 17.4±6.7,33.1±7.2,which were significantly higher than those in group 1 (13.1±8.7,t=-3.379,P=0.001;56.5±22.6,t=-2.268,P=0.025;14.1±8.1,t=-2.283,P=0.024;28.9±8.8,t=-2.613,P=0.009). Conclusion Compared with fixed tube voltage on the second-generation dual-source CT techniques,topogram-based automatic tube potential selection on third-generation dual-source CT can reduce radiation dose without decreasing image quality in imaging solid pancreatic lesions.