BACKGROUND Recurrence is the major challenge facing endoscopic submucosal dissection(ESD)-based treatment therapies for early gastric cancer(EGC).Urgent development of simple and easy surveillance approaches will enha...BACKGROUND Recurrence is the major challenge facing endoscopic submucosal dissection(ESD)-based treatment therapies for early gastric cancer(EGC).Urgent development of simple and easy surveillance approaches will enhance clinical treatment of the disease.AIM To explore the role of computed tomography(CT)recurrence in evaluating EGC after ESD treatment.METHODS We retrospectively recruited patients from our endoscopy department,between January 2002 and December 2015,and analyzed their basic characteristics,including symptoms,CT results,and results of endoscopy with biopsy,among others.RESULTS Among a total of 2150 patients EGC patients surveyed,1362 met our inclusion and exclusion criteria and were therefore enrolled in our study.The cohort’s sensitivity of CT for recurrent GC and specificity were 44.22%and 43.86%,respectively,with negative and positive predictive values of 40.15%(275/685)and 48.01%(325/677),respectively.The area under the curve of arterial and venous CT values for recurrent EGC were 0.545,and 0.604,respectively.Receiver operating characteristic curve revealed no statistically significant differences between arterial and venous CT values for recurrent EGC.CONCLUSION Enhanced CT has superior diagnostic efficacy,but less accuracy,compared to gold standard techniques in patients with recurrent EGC.展开更多
AIM To compare radiation dose and image quality of lowdose computed tomography(CT) protocol combined with hybrid-iterative reconstruction algorithm with standarddose CT examinations for follow-up of oncologic patients...AIM To compare radiation dose and image quality of lowdose computed tomography(CT) protocol combined with hybrid-iterative reconstruction algorithm with standarddose CT examinations for follow-up of oncologic patients. METHODS Fifty-one patients with known malignant diseases which underwent, during clinical follow-up, both standarddose and low-dose whole-body CT scans were enrolled. Low-dose CT was performed on 256-row scanner, with 120 kV and automated m A modulation, and iterative reconstruction algorithm. Standard-dose CT was performed on 16-rows scanner, with 120 kV, 200-400 m As(depending on patient weight). We evaluated density values and signal-to-noise ratio, along with image noise(SD), sharpness and diagnostic quality with 4-point scale.RESULTS Density values in liver, spleen and aorta were higher in lowdose images(liver 112.55 HU vs 103.90 HU, P < 0.001), as SD values in liver and spleen(liver 16.81 vs 14.41). Volumetric-Computed-Tomographic-Dose-Index(CTDIvol) and Dose-Length-Product(DLP) were significantly lower in low-dose CT as compared to standard-dose(DLP 1025.6 m Gy*cm vs 1429.2 m Gy*cm, P < 0.001) with overall dose reduction of 28.9%. Qualitative analysis did not reveal significant differences in image noise and diagnostic quality.CONCLUSION Automatic tube-current modulation combined with hybriditerative algorithm allows radiation dose reduction of 28.9% without loss of diagnostic quality, being useful in reducing dose exposure in oncologic patients.展开更多
To minimize radiation risk,dose reduction is important in the diagnostic and therapeutic applications of computed tomography(CT).However,image noise degrades image quality owing to the reduced X-ray dose and a possibl...To minimize radiation risk,dose reduction is important in the diagnostic and therapeutic applications of computed tomography(CT).However,image noise degrades image quality owing to the reduced X-ray dose and a possible unacceptably reduced diagnostic performance.Deep learning approaches with convolutional neural networks(CNNs)have been proposed for natural image denoising;however,these approaches might introduce image blurring or loss of original gradients.The aim of this study was to compare the dose-dependent properties of a CNN-based denoising method for low-dose CT with those of other noise-reduction methods on unique CT noise-simulation images.To simulate a low-dose CT image,a Poisson noise distribution was introduced to normal-dose images while convoluting the CT unit-specific modulation transfer function.An abdominal CT of 100 images obtained from a public database was adopted,and simulated dose-reduction images were created from the original dose at equal 10-step dose-reduction intervals with a final dose of 1/100.These images were denoised using the denoising network structure of CNN(DnCNN)as the general CNN model and for transfer learning.To evaluate the image quality,image similarities determined by the structural similarity index(SSIM)and peak signal-to-noise ratio(PSNR)were calculated for the denoised images.Significantly better denoising,in terms of SSIM and PSNR,was achieved by the DnCNN than by other image denoising methods,especially at the ultra-low-dose levels used to generate the 10%and 5%dose-equivalent images.Moreover,the developed CNN model can eliminate noise and maintain image sharpness at these dose levels and improve SSIM by approximately 10%from that of the original method.In contrast,under small dose-reduction conditions,this model also led to excessive smoothing of the images.In quantitative evaluations,the CNN denoising method improved the low-dose CT and prevented over-smoothing by tailoring the CNN model.展开更多
BACKGROUND This study aimed to analyze the predictive value of multi-slice spiral computed tomography(CT)perfusion imaging for upper gastrointestinal bleeding in patients with cirrhotic portal hypertension.A total of ...BACKGROUND This study aimed to analyze the predictive value of multi-slice spiral computed tomography(CT)perfusion imaging for upper gastrointestinal bleeding in patients with cirrhotic portal hypertension.A total of 62 patients with cirrhotic portal hypertension and 28 healthy individuals were included.The results showed that multi-slice spiral CT perfusion imaging had a significant predictive value for upper gastrointestinal bleeding in patients with cirrhotic portal hypertension.The vascular area,number of vascular cross-sections,and gastric coronary vein diameter(GCVD)showed high predictive values,with the vascular area having the best predictive value.AIM To investigate the predictive accuracy of multi-slice spiral CT perfusion imaging for upper gastrointestinal bleeding in patients with cirrhosis and portal hypertension.METHODS This study included 62 patients with cirrhotic portal hypertension(disease group)and 28 healthy individuals(control group).The disease group was further divided into two subgroups:Group A(n=27,bleeding)and group B(n=35,no bleeding).All patients underwent multi-slice spiral CT perfusion imaging at our hospital,and we compared various parameters such as liver blood flow,vein size,number of blood vessels,and blood vessel area between the two groups.We employed statistical analysis to identify factors associated with upper gastrointestinal bleeding and created a graph comparing the predictive value of different factors for bleeding.RESULTS We found no difference in hepatic artery(HAP)levels among the three groups(all P>0.05).The portal vein levels in groups A and B were much lower than in the control group;group A was much lower than group B(all P<0.05).The HAP perfusion index levels in groups A and B were much higher than in the control group;group A was much higher than group B(all P<0.05).The portal vein diameter,splenic vein diameter,and GCVD levels in groups A and B were much higher than in the control group;those in group A were much higher than those in group B(all P<0.05).The number of blood vessels and blood vessel area in groups A and B were much higher than in the control group;those in group A were much higher than those in group B(all P<0.05).The statistical method showed a strong link between GCVD,number of blood vessels,blood vessel area,and upper gastrointestinal bleeding(odds ratio=1.275,1.346,1.397,P<0.05).The graph showed that GCVD,number of blood vessels,and blood vessel area could predict bleeding well,with blood vessel area having the best prediction power.CONCLUSION That multi-slice spiral CT perfusion imaging can predict upper gastrointestinal bleeding well in patients with cirrhosis and high blood pressure in the portal vein.GCVD,number of blood vessels,and blood vessel area had high prediction power.The blood vessel area had the best prediction power,with an area under the curve of 0.831.展开更多
BACKGROUND The reliability of preoperative nodal diagnosis of advanced gastric cancer by multi-detector spiral computed tomography(MDCT)is still unclear.AIM To examine the diagnostic ability of MDCT more precisely by ...BACKGROUND The reliability of preoperative nodal diagnosis of advanced gastric cancer by multi-detector spiral computed tomography(MDCT)is still unclear.AIM To examine the diagnostic ability of MDCT more precisely by using data on intranodal pathological metastatic patterns.METHODS A total of 108 patients with advanced gastric cancer who underwent MDCT and curative gastrectomy at Kanazawa Medical University Hospital were enrolled in this study.The nodal sizes measured on computed tomography(CT)images were compared with the pathology results.A receiver-operating characteristic curve was constructed,from which the critical value(CV)was calculated by using the data of the first 69 patients retrospectively.By using the CV,sensitivity and specificity were calculated with prospectively collected data from 39 consecutive patients.This enabled a more precise one-to-one correspondence of lymph nodes between CT and pathological examination by using the size data of lymph node mapping.The intranodal pathological metastatic patterns were classified into the following four types:Small nodular,peripheral,large nodular,and diffuse.RESULTS Although all the cases were clinically suspected as having metastasis,81 had lymph node metastasis and 27 had no metastasis.The number of dissected,detected on CT,and metastatic nodes were,4241,897,and 801,respectively.The CV obtained from the receiver-operating characteristic was 7.6 mm for the long axis.The sensitivity was 91.4%and the specificity was 47.3%in the prospective phase.The large nodular and diffuse metastases were easy to diagnose becausemetastatic nodes with a large axis often exhibit these forms.CONCLUSION The ability of MDCT to contribute to a nodal diagnosis of advanced gastric cancer was examined prospectively with precise size data from node mapping,using a CV of 7.6 mm for the long axis that was calculated from the retrospectively collected data.The sensitivity was as high as 91%,and would be improved when referring to the enhanced patterns.However,its specificity was as low as 47%,because most of metastatic nodes in gastric cancer being small in size.The small nodular or peripheral type metastatic nodes were often small and considered difficult to diagnose.展开更多
BACKGROUND The biological characteristics of gastric stromal tumors are complex,and their incidence has increased in recent years.Gastric stromal tumors(GST)have potential malignant tendencies,and the probability of t...BACKGROUND The biological characteristics of gastric stromal tumors are complex,and their incidence has increased in recent years.Gastric stromal tumors(GST)have potential malignant tendencies,and the probability of transformation into malignant tumors is as high as 20%-30%.AIM To investigate the value of multi-slice spiral computed tomography(MSCT)in the differential diagnosis of GST and benign gastric polyps,and GST risk stratification assessment.METHODS We included 64 patients with GST(GST group)and 60 with benign gastric polyps(control group),confirmed by pathological examination after surgery in PLA General Hospital,from January 2016 to June 2021.The differences in the MSCT imaging characteristic parameters and enhanced CT values between the two groups before surgery were compared.According to the National Institutes of Health’s standard,GST is divided into low-and high-risk groups for MSCT imaging characteristic parameters and enhanced CT values.RESULTS The incidences of extraluminal growth,blurred boundaries,and ulceration in the GST group were significantly higher than those in the control group(P<0.05).The CT values and enhanced peak CT values in the arterial phase in the CST group were higher than those in the control group(P<0.05).The MSCT differential diagnosis of GST and gastric polyp sensitivity,specificity,misdiagnosis rate,missed diagnosis rate,and areas under the curve(AUCs)were 73.44%,83.33%,26.56%,16.67%,0.784,respectively.The receiver operating characteristic curves were plotted with the arterial CT value and enhanced peak CT value,with a statistical difference.The results showed that the sensitivity,specificity,misdiagnosis rate,missed diagnosis rate,and AUC value of arterial CT in the differential diagnosis of GST and gastric polyps were 80.18%,62.20%,19.82%,37.80%,and 0.710,respectively.The sensitivity,specificity,misdiagnosis rate,missed diagnosis rate,and AUC value of the enhanced peak CT value in the differential diagnosis of GST and gastric polyps were 67.63%,60.40%,32.37%,39.60%,and 0.710,respectively.The incidence of blurred lesion boundaries and ulceration in the high-risk group was significantly higher than that in the low-risk group(P<0.05).The arterial phase and enhanced peak CT values in the high-risk group were significantly higher than those in the low-risk group(P<0.05).CONCLUSION Presurgical MSCT examination has important value in the differential diagnosis of GST and gastric benign polyps and can effectively evaluate the risk grade of GST patients.展开更多
BACKGROUND Older people are more likely to experience pelvic fractures than younger people.Multi-slice spiral computed tomography(CT)uses three-dimensional(3D)reconstruction technology to generate 3D images that can c...BACKGROUND Older people are more likely to experience pelvic fractures than younger people.Multi-slice spiral computed tomography(CT)uses three-dimensional(3D)reconstruction technology to generate 3D images that can clearly demonstrate the 3D space of fractures and detect fractures at a higher rate.AIM To investigate the clinical value of multi-slice spiral CT 3D reconstruction in the diagnosis of unstable pelvic fractures in the elderly as well as the effect of less invasive stabilization.METHODS A total of 86 patients with unstable pelvic fractures treated between March 2016 and March 2019 underwent femoral supracondylar bone traction before surgery.Pelvic radiography and multi-row spiral CT were performed successively once the patient’s vital signs and hemodynamic indices were stable.Secondary processing of the original data was performed to obtain 3D reconstruction images and determine the vertical displacement of the pelvis.After basic or complete reduction,minimally invasive internal fixation using hollow lag screws was performed.The detection rates of fracture location and classification by X-ray and CT reconstruction were compared.Patients were divided into two groups according to the presence or absence of preoperative 3D reconstruction to compare postoperative reduction,wound healing time,fracture healing time,hospitalization time,visual analog scale(VAS)score,poor internal fixation,and functional recovery.RESULTS The diagnostic coincidence rates of X-rays for pubic symphysis,ilium wing,sacroiliac periarticular,and sacral fractures were lower than those of CT reconstruction.The coincidence rate of CT reconstruction in the clinical classification of pelvic fractures was 100%,whereas 11 cases were misdiagnosed by X-ray;the total coincidence rate was 87.21%.The total excellent and good rates of postoperative reduction were significantly higher in the study group than in the control group(P<0.05).The wound healing,fracture healing,and hospitalization times were significantly shorter in the study group than in the control group(P<0.05).The VAS scores decreased in both groups postoperatively and were lower in the study group than in the control group(P<0.05).The total incidence of poor postoperative internal fixation was significantly lower in the study group than in the control group(P<0.05).The overall rate of postoperative functional recovery was significantly higher in the study group than in the control group(P<0.05).CONCLUSION Multi-slice spiral CT has high guiding significance for the diagnosis,classification,and treatment of unstable pelvic fractures in the elderly.Preoperative 3D reconstruction can effectively shorten the operation time and promote fracture healing,while minimally invasive internal fixation can effectively reduce pain and promote functional recovery of fracture sites,making it worthy of clinical application.展开更多
Objective: To evaluate the safety and clinical efficacy of segmental radiofrequency ablation of pulmonary vein (PV)ostia for patients with refractory paroxysmal atrial fibrillation (AF) under multi-slice spiral comput...Objective: To evaluate the safety and clinical efficacy of segmental radiofrequency ablation of pulmonary vein (PV)ostia for patients with refractory paroxysmal atrial fibrillation (AF) under multi-slice spiral computed tomography (MSCT)guidance before the procedure. Methods: A series of 58 consecutive patients with refractory paroxysmal AF were enrolled to undergo segmental radiofrequency ablation ofPV ostia. The 36 male and 22 female patients with mean age of (57.4±9.5) (32~79)atrium (LA) and proximal PVs. Patients then underwent segmental radiofrequency ablation of PV ostia using PV circular mapping catheter manipulated several times to ensure complete isolation between PVs and LA. Results: No complications occurred during the procedure. One patient developed delayed cardiac tamponade, which was drained percutaneously. The mean follow-up time was (17.1±9.3) months. Forty-one patients (95%) experienced improved quality of life one month after the procedure. Thirty-six patients (83%) showed stable sinus rhythm, while 10 patients (23%) required additional anti-arrhythmic drugs. AF returned≥1time in 6 (14%) patients who underwent anti-arrhythmic drug therapy, but the number of episodes was less than that before the procedure. However, one patient experienced recurrent episodes of atrial flutter. Conclusion: It is safe and effective to perform segmental radiofrequency ablation of PV ostia for patients with refractory paroxysmal AF using MSCT guidance mappening.展开更多
Choroidal osteoma (CO) is a rare, ossifying benign tumor originated in the choroid that typically occurs in otherwise healthy young women (1,2). It is characterized by a yellowish, well demarcated lesion in the juxtap...Choroidal osteoma (CO) is a rare, ossifying benign tumor originated in the choroid that typically occurs in otherwise healthy young women (1,2). It is characterized by a yellowish, well demarcated lesion in the juxtapapillary or macular area. The diagnosis is clinical and can be confirmed with the use of fluorescein or indocyanine angiography, optical coherence tomography, computed tomography or magnetic resonance imaging. Choroidal neovascularization or subretinal fluid, the main causes for vision loss, can be treated with laser therapy, photodynamic therapy or intravitreal antivascular endothelial growth factor therapy. We present a case of choroidal osteoma, showing the role of the high resolution 3D spiral computed tomography.展开更多
Objective: The standard treatment for patients with locally advanced gastric cancer has relied on perioperativeradio-chemotherapy or chemotherapy and surgery. The aim of this study was to investigate the wealth of ra...Objective: The standard treatment for patients with locally advanced gastric cancer has relied on perioperativeradio-chemotherapy or chemotherapy and surgery. The aim of this study was to investigate the wealth of radiomicsfor pre-treatment computed tomography (CT) in the prediction of the pathological response of locally advancedgastric cancer with preoperative chemotherapy.Methods: Thirty consecutive patients with CT-staged Ⅱ/Ⅲ gastric cancer receiving neoadjuvant chemotherapywere enrolled in this study between December 2014 and March 2017. All patients underwent upper abdominal CTduring the unenhanced, late arterial phase (AP) and portal venous phase (PP) before the administration ofneoadjuvant chemotherapy. In total, 19,985 radiomics features were extracted in the AP and PP for each patient.Four methods were adopted during feature selection and eight methods were used in the process of building theclassifier model. Thirty-two combinations of feature selection and classification methods were examined. Receiveroperating characteristic (ROC) curves were used to evaluate the capability of each combination of feature selectionand classification method to predict a non-good response (non-GR) based on tumor regression grade (TRG).Results: The mean area under the curve (AUC) ranged from 0.194 to 0.621 in the AP, and from 0.455 to 0.722in the PP, according to different combinations of feature selection and the classification methods. There was onlyone cross-combination machine-learning method indicating a relatively higher AUC (〉0.600) in the AP, while 12cross-combination machine-learning methods presented relatively higher AUCs (all 〉0.600) in the PP. The featureselection method adopted by a filter based on linear discriminant analysis + classifier of random forest achieved asignificantly prognostic performance in the PP (AUC, 0.722~0.108; accuracy, 0.793; sensitivity, 0.636; specificity,0.889; Z=2.039; P=0.041).Conclusions: It is possible to predict non-GR after neoadiuvant chemotherapy in locally advanced gastriccancers based on the radiomics of CT.展开更多
Background:Screening using low-dose computed tomography(LDCT)is a more effective approach and has the potential to detect lung cancer more accurately.We aimed to conduct a meta-analysis to estimate the accuracy of pop...Background:Screening using low-dose computed tomography(LDCT)is a more effective approach and has the potential to detect lung cancer more accurately.We aimed to conduct a meta-analysis to estimate the accuracy of population-based screening studies primarily assessing baseline LDCT screening for lung cancer.Methods:MEDLINE,Excerpta Medica Database,and Web of Science were searched for articles published up to April 10,2022.According to the inclusion and exclusion criteria,the data of true positives,false-positives,false negatives,and true negatives in the screening test were extracted.Quality Assessment of Diagnostic Accuracy Studies-2 was used to evaluate the quality of the literature.A bivariate random effects model was used to estimate pooled sensitivity and specificity.The area under the curve(AUC)was calculated by using hierarchical summary receiver-operating characteristics analysis.Heterogeneity between studies was measured using the Higgins I 2 statistic,and publication bias was evaluated using a Deeks’funnel plot and linear regression test.Results:A total of 49 studies with 157,762 individuals were identified for the final qualitative synthesis;most of them were from Europe and America(38 studies),ten were from Asia,and one was from Oceania.The recruitment period was 1992 to 2018,and most of the subjects were 40 to 75 years old.The analysis showed that the AUC of lung cancer screening by LDCT was 0.98(95%CI:0.96-0.99),and the overall sensitivity and specificity were 0.97(95%CI:0.94-0.98)and 0.87(95%CI:0.82-0.91),respectively.The funnel plot and test results showed that there was no significant publication bias among the included studies.Conclusions:Baseline LDCT has high sensitivity and specificity as a screening technique for lung cancer.However,long-term follow-up of the whole study population(including those with a negative baseline screening result)should be performed to enhance the accuracy of LDCT screening.展开更多
Displacement of a cardiac pacemaker lead or myocardial perforation by a lead is an infrequent complication of pacemaker implantation. While standard cardiac CT is useful for diagnosing such complications when routine ...Displacement of a cardiac pacemaker lead or myocardial perforation by a lead is an infrequent complication of pacemaker implantation. While standard cardiac CT is useful for diagnosing such complications when routine examinations can not, the potential risks associated with exposure to the high doses of radiation used in CT are of concern. Here, we report three cases </span><span style="font-family:"white-space:normal;">in which pacemaker lead displacement or myocardial perforation was definitively diagnosed by l</span><span style="font-family:"white-space:normal;">ow-dose cardiac CT used in the high-pitch spiral mode, when other more routine examinations failed to suggest their occurrence.</span><span style="font-family:"white-space:normal;"> </span><span style="font-family:"white-space:normal;">The mean dose of radiation used for definitively diagnosing the three patients was relatively low (2.19 mSv).展开更多
Background:According to the World Health Organization,China is one of 22 countries with serious tuberculosis(TB)infections and one of the 27 countries with serious multidrug-resistant TB strains.Despite the decline of...Background:According to the World Health Organization,China is one of 22 countries with serious tuberculosis(TB)infections and one of the 27 countries with serious multidrug-resistant TB strains.Despite the decline of tuberculosis in the overall population,healthcare workers(HCWs)are still at a high risk of infection.Compared with high-income countries,the TB prevalence among HCWs is higher in low-and middle-income countries.Low-dose computed tomography(LDCT)is becoming more popular due to its superior sensitivity and lower radiation dose.However,there have been no reports about active pulmonary tuberculosis(PTB)among HCWs as assessed with LDCT.The purposes of this study were to examine PTB statuses in HCWs in hospitals specializing in TB treatment and explore the significance of the application of LDCT to these workers.Methods:This study retrospectively analysed the physical examination data of healthcare workers in the Beijing Chest Hospital from September 2012 to December 2015.Low-dose lung CT examinations were performed in all cases.The comparisons between active and inactive PTB according to the CT findings were made using the Pearson chi-square test or the Fisher’s exact test.Comparisons between the incidences of active PTB in high-risk areas and non-high-risk areas were performed using the Pearson chi-square test.Analyses of active PTB were performed according to different ages,numbers of years on the job,and the risks of the working areas.Active PTB as diagnosed by the LDCT examinations alone was compared with the final comprehensive diagnoses,and the sensitivity and positive predictive value were calculated.Results:A total of 1012 participants were included in this study.During the 4-year period of medical examinations,active PTB was found in 19 cases,and inactive PTB was found in 109 cases.The prevalence of active PTB in the participants was 1.24%,0.67%,0.81%,and 0.53%for years 2012 to 2015.The corresponding incidences of active PTB among the tuberculosis hospital participants were 0.86%,0.41%,0.54%,and 0.26%.Most HCWs with active TB(78.9%,15/19)worked in the high-risk areas of the hospital.There was a significant difference in the incidences of active PTB between the HCWs who worked in the high-risk and non-high-risk areas(odds ratio[OR],14.415;95%confidence interval(CI):4.733-43.896).Comparisons of the CT signs between the active and inactive groups via chi-square tests revealed that the tree-in-bud,cavity,fibrous shadow,and calcification signs exhibited significant differences(P=0.000,0.021,0.001,and 0.024,respectively).Tree-in-bud and cavity opacities suggest active pulmonary tuberculosis,whereas fibrous shadow and calcification opacities are the main features of inactive pulmonary tuberculosis.Comparison with the final comprehensive diagnoses revealed that the sensitivity and positive predictive value of the diagnoses of active PTB based on LDCT alone were 100%and 86.4%,respectively.Conclusions:Healthcare workers in tuberculosis hospitals are a high-risk group for active PTB.Yearly LDCT examinations of such high-risk groups are feasible and necessary.展开更多
Background The incidence of thyroid cancer has been increasing.Our aim was to evaluate the efficacy of low-dose dualphase helical computed tomography (CT) in the characterization of thyroid lesions,and to discuss th...Background The incidence of thyroid cancer has been increasing.Our aim was to evaluate the efficacy of low-dose dualphase helical computed tomography (CT) in the characterization of thyroid lesions,and to discuss the relationship between image characteristics and their pathology.Methods One hundred and six patients with thyroid lesions underwent low-dose dual-phase helical CT after the injection of contrast material.CT scans were obtained at arterial and venous phase with delays of 25 and 65 seconds,and tube current of 60 and 120 mA,respectively.The attenuation change in the lesion between the arterial and venous phase was analyzed and categorized as "increased," "decreased," "mixed" or "no change." Results Histopathologic diagnosis was obtained by surgery in 106 patients (115 lesions).Of the 106 patients,45 had nodular goiter,5 thyroid adenoma,6 thyroiditis,and 50 papillary thyroid carcinoma (PTC) (59 lesions).The attenuation value showed a significant difference (P <0.05) between the arterial and venous phase for the high attenuation area.There was statistical significant difference in terms of attenuation value in high attenuation areas at both phases and in low attenuation areas on arterial phase between nodular goiter and PTC (P <0.05).However,there was no significant difference in attenuation value between adenoma and PTC.Twenty-nine cases (76.3%) of goiter manifested mixed type,3 cases (3/5) of adenoma showed decreased type,6 cases (6/6) of thyroiditis showed increased type,and 55 cases (93.2%) of PTC showed decreased type attenuation.The sensitivity,specificity for thyroid carcinoma by dual-phase CT were 94.9% and 80.4% respectively.The overall diagnostic accuracy for thyroid lesions by dual-phase CT was 87.8%.Conclusions The performance of dual-phase helical CT is related to the pathological structure of the lesions.The analysis of enhancement patterns by using dual-phase helical CT will be helpful in the differential diagnosis of thyroid lesions.展开更多
文摘BACKGROUND Recurrence is the major challenge facing endoscopic submucosal dissection(ESD)-based treatment therapies for early gastric cancer(EGC).Urgent development of simple and easy surveillance approaches will enhance clinical treatment of the disease.AIM To explore the role of computed tomography(CT)recurrence in evaluating EGC after ESD treatment.METHODS We retrospectively recruited patients from our endoscopy department,between January 2002 and December 2015,and analyzed their basic characteristics,including symptoms,CT results,and results of endoscopy with biopsy,among others.RESULTS Among a total of 2150 patients EGC patients surveyed,1362 met our inclusion and exclusion criteria and were therefore enrolled in our study.The cohort’s sensitivity of CT for recurrent GC and specificity were 44.22%and 43.86%,respectively,with negative and positive predictive values of 40.15%(275/685)and 48.01%(325/677),respectively.The area under the curve of arterial and venous CT values for recurrent EGC were 0.545,and 0.604,respectively.Receiver operating characteristic curve revealed no statistically significant differences between arterial and venous CT values for recurrent EGC.CONCLUSION Enhanced CT has superior diagnostic efficacy,but less accuracy,compared to gold standard techniques in patients with recurrent EGC.
文摘AIM To compare radiation dose and image quality of lowdose computed tomography(CT) protocol combined with hybrid-iterative reconstruction algorithm with standarddose CT examinations for follow-up of oncologic patients. METHODS Fifty-one patients with known malignant diseases which underwent, during clinical follow-up, both standarddose and low-dose whole-body CT scans were enrolled. Low-dose CT was performed on 256-row scanner, with 120 kV and automated m A modulation, and iterative reconstruction algorithm. Standard-dose CT was performed on 16-rows scanner, with 120 kV, 200-400 m As(depending on patient weight). We evaluated density values and signal-to-noise ratio, along with image noise(SD), sharpness and diagnostic quality with 4-point scale.RESULTS Density values in liver, spleen and aorta were higher in lowdose images(liver 112.55 HU vs 103.90 HU, P < 0.001), as SD values in liver and spleen(liver 16.81 vs 14.41). Volumetric-Computed-Tomographic-Dose-Index(CTDIvol) and Dose-Length-Product(DLP) were significantly lower in low-dose CT as compared to standard-dose(DLP 1025.6 m Gy*cm vs 1429.2 m Gy*cm, P < 0.001) with overall dose reduction of 28.9%. Qualitative analysis did not reveal significant differences in image noise and diagnostic quality.CONCLUSION Automatic tube-current modulation combined with hybriditerative algorithm allows radiation dose reduction of 28.9% without loss of diagnostic quality, being useful in reducing dose exposure in oncologic patients.
基金This work was supported by JSPS KAKENHI,No.18 K15563.
文摘To minimize radiation risk,dose reduction is important in the diagnostic and therapeutic applications of computed tomography(CT).However,image noise degrades image quality owing to the reduced X-ray dose and a possible unacceptably reduced diagnostic performance.Deep learning approaches with convolutional neural networks(CNNs)have been proposed for natural image denoising;however,these approaches might introduce image blurring or loss of original gradients.The aim of this study was to compare the dose-dependent properties of a CNN-based denoising method for low-dose CT with those of other noise-reduction methods on unique CT noise-simulation images.To simulate a low-dose CT image,a Poisson noise distribution was introduced to normal-dose images while convoluting the CT unit-specific modulation transfer function.An abdominal CT of 100 images obtained from a public database was adopted,and simulated dose-reduction images were created from the original dose at equal 10-step dose-reduction intervals with a final dose of 1/100.These images were denoised using the denoising network structure of CNN(DnCNN)as the general CNN model and for transfer learning.To evaluate the image quality,image similarities determined by the structural similarity index(SSIM)and peak signal-to-noise ratio(PSNR)were calculated for the denoised images.Significantly better denoising,in terms of SSIM and PSNR,was achieved by the DnCNN than by other image denoising methods,especially at the ultra-low-dose levels used to generate the 10%and 5%dose-equivalent images.Moreover,the developed CNN model can eliminate noise and maintain image sharpness at these dose levels and improve SSIM by approximately 10%from that of the original method.In contrast,under small dose-reduction conditions,this model also led to excessive smoothing of the images.In quantitative evaluations,the CNN denoising method improved the low-dose CT and prevented over-smoothing by tailoring the CNN model.
基金Supported by the Hebei Medical Science Project Research Program Project,No.20201411.
文摘BACKGROUND This study aimed to analyze the predictive value of multi-slice spiral computed tomography(CT)perfusion imaging for upper gastrointestinal bleeding in patients with cirrhotic portal hypertension.A total of 62 patients with cirrhotic portal hypertension and 28 healthy individuals were included.The results showed that multi-slice spiral CT perfusion imaging had a significant predictive value for upper gastrointestinal bleeding in patients with cirrhotic portal hypertension.The vascular area,number of vascular cross-sections,and gastric coronary vein diameter(GCVD)showed high predictive values,with the vascular area having the best predictive value.AIM To investigate the predictive accuracy of multi-slice spiral CT perfusion imaging for upper gastrointestinal bleeding in patients with cirrhosis and portal hypertension.METHODS This study included 62 patients with cirrhotic portal hypertension(disease group)and 28 healthy individuals(control group).The disease group was further divided into two subgroups:Group A(n=27,bleeding)and group B(n=35,no bleeding).All patients underwent multi-slice spiral CT perfusion imaging at our hospital,and we compared various parameters such as liver blood flow,vein size,number of blood vessels,and blood vessel area between the two groups.We employed statistical analysis to identify factors associated with upper gastrointestinal bleeding and created a graph comparing the predictive value of different factors for bleeding.RESULTS We found no difference in hepatic artery(HAP)levels among the three groups(all P>0.05).The portal vein levels in groups A and B were much lower than in the control group;group A was much lower than group B(all P<0.05).The HAP perfusion index levels in groups A and B were much higher than in the control group;group A was much higher than group B(all P<0.05).The portal vein diameter,splenic vein diameter,and GCVD levels in groups A and B were much higher than in the control group;those in group A were much higher than those in group B(all P<0.05).The number of blood vessels and blood vessel area in groups A and B were much higher than in the control group;those in group A were much higher than those in group B(all P<0.05).The statistical method showed a strong link between GCVD,number of blood vessels,blood vessel area,and upper gastrointestinal bleeding(odds ratio=1.275,1.346,1.397,P<0.05).The graph showed that GCVD,number of blood vessels,and blood vessel area could predict bleeding well,with blood vessel area having the best prediction power.CONCLUSION That multi-slice spiral CT perfusion imaging can predict upper gastrointestinal bleeding well in patients with cirrhosis and high blood pressure in the portal vein.GCVD,number of blood vessels,and blood vessel area had high prediction power.The blood vessel area had the best prediction power,with an area under the curve of 0.831.
文摘BACKGROUND The reliability of preoperative nodal diagnosis of advanced gastric cancer by multi-detector spiral computed tomography(MDCT)is still unclear.AIM To examine the diagnostic ability of MDCT more precisely by using data on intranodal pathological metastatic patterns.METHODS A total of 108 patients with advanced gastric cancer who underwent MDCT and curative gastrectomy at Kanazawa Medical University Hospital were enrolled in this study.The nodal sizes measured on computed tomography(CT)images were compared with the pathology results.A receiver-operating characteristic curve was constructed,from which the critical value(CV)was calculated by using the data of the first 69 patients retrospectively.By using the CV,sensitivity and specificity were calculated with prospectively collected data from 39 consecutive patients.This enabled a more precise one-to-one correspondence of lymph nodes between CT and pathological examination by using the size data of lymph node mapping.The intranodal pathological metastatic patterns were classified into the following four types:Small nodular,peripheral,large nodular,and diffuse.RESULTS Although all the cases were clinically suspected as having metastasis,81 had lymph node metastasis and 27 had no metastasis.The number of dissected,detected on CT,and metastatic nodes were,4241,897,and 801,respectively.The CV obtained from the receiver-operating characteristic was 7.6 mm for the long axis.The sensitivity was 91.4%and the specificity was 47.3%in the prospective phase.The large nodular and diffuse metastases were easy to diagnose becausemetastatic nodes with a large axis often exhibit these forms.CONCLUSION The ability of MDCT to contribute to a nodal diagnosis of advanced gastric cancer was examined prospectively with precise size data from node mapping,using a CV of 7.6 mm for the long axis that was calculated from the retrospectively collected data.The sensitivity was as high as 91%,and would be improved when referring to the enhanced patterns.However,its specificity was as low as 47%,because most of metastatic nodes in gastric cancer being small in size.The small nodular or peripheral type metastatic nodes were often small and considered difficult to diagnose.
文摘BACKGROUND The biological characteristics of gastric stromal tumors are complex,and their incidence has increased in recent years.Gastric stromal tumors(GST)have potential malignant tendencies,and the probability of transformation into malignant tumors is as high as 20%-30%.AIM To investigate the value of multi-slice spiral computed tomography(MSCT)in the differential diagnosis of GST and benign gastric polyps,and GST risk stratification assessment.METHODS We included 64 patients with GST(GST group)and 60 with benign gastric polyps(control group),confirmed by pathological examination after surgery in PLA General Hospital,from January 2016 to June 2021.The differences in the MSCT imaging characteristic parameters and enhanced CT values between the two groups before surgery were compared.According to the National Institutes of Health’s standard,GST is divided into low-and high-risk groups for MSCT imaging characteristic parameters and enhanced CT values.RESULTS The incidences of extraluminal growth,blurred boundaries,and ulceration in the GST group were significantly higher than those in the control group(P<0.05).The CT values and enhanced peak CT values in the arterial phase in the CST group were higher than those in the control group(P<0.05).The MSCT differential diagnosis of GST and gastric polyp sensitivity,specificity,misdiagnosis rate,missed diagnosis rate,and areas under the curve(AUCs)were 73.44%,83.33%,26.56%,16.67%,0.784,respectively.The receiver operating characteristic curves were plotted with the arterial CT value and enhanced peak CT value,with a statistical difference.The results showed that the sensitivity,specificity,misdiagnosis rate,missed diagnosis rate,and AUC value of arterial CT in the differential diagnosis of GST and gastric polyps were 80.18%,62.20%,19.82%,37.80%,and 0.710,respectively.The sensitivity,specificity,misdiagnosis rate,missed diagnosis rate,and AUC value of the enhanced peak CT value in the differential diagnosis of GST and gastric polyps were 67.63%,60.40%,32.37%,39.60%,and 0.710,respectively.The incidence of blurred lesion boundaries and ulceration in the high-risk group was significantly higher than that in the low-risk group(P<0.05).The arterial phase and enhanced peak CT values in the high-risk group were significantly higher than those in the low-risk group(P<0.05).CONCLUSION Presurgical MSCT examination has important value in the differential diagnosis of GST and gastric benign polyps and can effectively evaluate the risk grade of GST patients.
文摘BACKGROUND Older people are more likely to experience pelvic fractures than younger people.Multi-slice spiral computed tomography(CT)uses three-dimensional(3D)reconstruction technology to generate 3D images that can clearly demonstrate the 3D space of fractures and detect fractures at a higher rate.AIM To investigate the clinical value of multi-slice spiral CT 3D reconstruction in the diagnosis of unstable pelvic fractures in the elderly as well as the effect of less invasive stabilization.METHODS A total of 86 patients with unstable pelvic fractures treated between March 2016 and March 2019 underwent femoral supracondylar bone traction before surgery.Pelvic radiography and multi-row spiral CT were performed successively once the patient’s vital signs and hemodynamic indices were stable.Secondary processing of the original data was performed to obtain 3D reconstruction images and determine the vertical displacement of the pelvis.After basic or complete reduction,minimally invasive internal fixation using hollow lag screws was performed.The detection rates of fracture location and classification by X-ray and CT reconstruction were compared.Patients were divided into two groups according to the presence or absence of preoperative 3D reconstruction to compare postoperative reduction,wound healing time,fracture healing time,hospitalization time,visual analog scale(VAS)score,poor internal fixation,and functional recovery.RESULTS The diagnostic coincidence rates of X-rays for pubic symphysis,ilium wing,sacroiliac periarticular,and sacral fractures were lower than those of CT reconstruction.The coincidence rate of CT reconstruction in the clinical classification of pelvic fractures was 100%,whereas 11 cases were misdiagnosed by X-ray;the total coincidence rate was 87.21%.The total excellent and good rates of postoperative reduction were significantly higher in the study group than in the control group(P<0.05).The wound healing,fracture healing,and hospitalization times were significantly shorter in the study group than in the control group(P<0.05).The VAS scores decreased in both groups postoperatively and were lower in the study group than in the control group(P<0.05).The total incidence of poor postoperative internal fixation was significantly lower in the study group than in the control group(P<0.05).The overall rate of postoperative functional recovery was significantly higher in the study group than in the control group(P<0.05).CONCLUSION Multi-slice spiral CT has high guiding significance for the diagnosis,classification,and treatment of unstable pelvic fractures in the elderly.Preoperative 3D reconstruction can effectively shorten the operation time and promote fracture healing,while minimally invasive internal fixation can effectively reduce pain and promote functional recovery of fracture sites,making it worthy of clinical application.
文摘Objective: To evaluate the safety and clinical efficacy of segmental radiofrequency ablation of pulmonary vein (PV)ostia for patients with refractory paroxysmal atrial fibrillation (AF) under multi-slice spiral computed tomography (MSCT)guidance before the procedure. Methods: A series of 58 consecutive patients with refractory paroxysmal AF were enrolled to undergo segmental radiofrequency ablation ofPV ostia. The 36 male and 22 female patients with mean age of (57.4±9.5) (32~79)atrium (LA) and proximal PVs. Patients then underwent segmental radiofrequency ablation of PV ostia using PV circular mapping catheter manipulated several times to ensure complete isolation between PVs and LA. Results: No complications occurred during the procedure. One patient developed delayed cardiac tamponade, which was drained percutaneously. The mean follow-up time was (17.1±9.3) months. Forty-one patients (95%) experienced improved quality of life one month after the procedure. Thirty-six patients (83%) showed stable sinus rhythm, while 10 patients (23%) required additional anti-arrhythmic drugs. AF returned≥1time in 6 (14%) patients who underwent anti-arrhythmic drug therapy, but the number of episodes was less than that before the procedure. However, one patient experienced recurrent episodes of atrial flutter. Conclusion: It is safe and effective to perform segmental radiofrequency ablation of PV ostia for patients with refractory paroxysmal AF using MSCT guidance mappening.
文摘Choroidal osteoma (CO) is a rare, ossifying benign tumor originated in the choroid that typically occurs in otherwise healthy young women (1,2). It is characterized by a yellowish, well demarcated lesion in the juxtapapillary or macular area. The diagnosis is clinical and can be confirmed with the use of fluorescein or indocyanine angiography, optical coherence tomography, computed tomography or magnetic resonance imaging. Choroidal neovascularization or subretinal fluid, the main causes for vision loss, can be treated with laser therapy, photodynamic therapy or intravitreal antivascular endothelial growth factor therapy. We present a case of choroidal osteoma, showing the role of the high resolution 3D spiral computed tomography.
基金supported by the National Key Research and Development Program of China (No.2017YFC1309100)the National Natural Scientific Foundation of China (No. 81771912)the Applied Basic Research Projects of Yunnan Province, China [No. 2015FB071 and No. 2017FE467-084]
文摘Objective: The standard treatment for patients with locally advanced gastric cancer has relied on perioperativeradio-chemotherapy or chemotherapy and surgery. The aim of this study was to investigate the wealth of radiomicsfor pre-treatment computed tomography (CT) in the prediction of the pathological response of locally advancedgastric cancer with preoperative chemotherapy.Methods: Thirty consecutive patients with CT-staged Ⅱ/Ⅲ gastric cancer receiving neoadjuvant chemotherapywere enrolled in this study between December 2014 and March 2017. All patients underwent upper abdominal CTduring the unenhanced, late arterial phase (AP) and portal venous phase (PP) before the administration ofneoadjuvant chemotherapy. In total, 19,985 radiomics features were extracted in the AP and PP for each patient.Four methods were adopted during feature selection and eight methods were used in the process of building theclassifier model. Thirty-two combinations of feature selection and classification methods were examined. Receiveroperating characteristic (ROC) curves were used to evaluate the capability of each combination of feature selectionand classification method to predict a non-good response (non-GR) based on tumor regression grade (TRG).Results: The mean area under the curve (AUC) ranged from 0.194 to 0.621 in the AP, and from 0.455 to 0.722in the PP, according to different combinations of feature selection and the classification methods. There was onlyone cross-combination machine-learning method indicating a relatively higher AUC (〉0.600) in the AP, while 12cross-combination machine-learning methods presented relatively higher AUCs (all 〉0.600) in the PP. The featureselection method adopted by a filter based on linear discriminant analysis + classifier of random forest achieved asignificantly prognostic performance in the PP (AUC, 0.722~0.108; accuracy, 0.793; sensitivity, 0.636; specificity,0.889; Z=2.039; P=0.041).Conclusions: It is possible to predict non-GR after neoadiuvant chemotherapy in locally advanced gastriccancers based on the radiomics of CT.
基金a grant from the Natural Science Foundation of Henan Province(No.212300410261).
文摘Background:Screening using low-dose computed tomography(LDCT)is a more effective approach and has the potential to detect lung cancer more accurately.We aimed to conduct a meta-analysis to estimate the accuracy of population-based screening studies primarily assessing baseline LDCT screening for lung cancer.Methods:MEDLINE,Excerpta Medica Database,and Web of Science were searched for articles published up to April 10,2022.According to the inclusion and exclusion criteria,the data of true positives,false-positives,false negatives,and true negatives in the screening test were extracted.Quality Assessment of Diagnostic Accuracy Studies-2 was used to evaluate the quality of the literature.A bivariate random effects model was used to estimate pooled sensitivity and specificity.The area under the curve(AUC)was calculated by using hierarchical summary receiver-operating characteristics analysis.Heterogeneity between studies was measured using the Higgins I 2 statistic,and publication bias was evaluated using a Deeks’funnel plot and linear regression test.Results:A total of 49 studies with 157,762 individuals were identified for the final qualitative synthesis;most of them were from Europe and America(38 studies),ten were from Asia,and one was from Oceania.The recruitment period was 1992 to 2018,and most of the subjects were 40 to 75 years old.The analysis showed that the AUC of lung cancer screening by LDCT was 0.98(95%CI:0.96-0.99),and the overall sensitivity and specificity were 0.97(95%CI:0.94-0.98)and 0.87(95%CI:0.82-0.91),respectively.The funnel plot and test results showed that there was no significant publication bias among the included studies.Conclusions:Baseline LDCT has high sensitivity and specificity as a screening technique for lung cancer.However,long-term follow-up of the whole study population(including those with a negative baseline screening result)should be performed to enhance the accuracy of LDCT screening.
文摘Displacement of a cardiac pacemaker lead or myocardial perforation by a lead is an infrequent complication of pacemaker implantation. While standard cardiac CT is useful for diagnosing such complications when routine examinations can not, the potential risks associated with exposure to the high doses of radiation used in CT are of concern. Here, we report three cases </span><span style="font-family:"white-space:normal;">in which pacemaker lead displacement or myocardial perforation was definitively diagnosed by l</span><span style="font-family:"white-space:normal;">ow-dose cardiac CT used in the high-pitch spiral mode, when other more routine examinations failed to suggest their occurrence.</span><span style="font-family:"white-space:normal;"> </span><span style="font-family:"white-space:normal;">The mean dose of radiation used for definitively diagnosing the three patients was relatively low (2.19 mSv).
文摘Background:According to the World Health Organization,China is one of 22 countries with serious tuberculosis(TB)infections and one of the 27 countries with serious multidrug-resistant TB strains.Despite the decline of tuberculosis in the overall population,healthcare workers(HCWs)are still at a high risk of infection.Compared with high-income countries,the TB prevalence among HCWs is higher in low-and middle-income countries.Low-dose computed tomography(LDCT)is becoming more popular due to its superior sensitivity and lower radiation dose.However,there have been no reports about active pulmonary tuberculosis(PTB)among HCWs as assessed with LDCT.The purposes of this study were to examine PTB statuses in HCWs in hospitals specializing in TB treatment and explore the significance of the application of LDCT to these workers.Methods:This study retrospectively analysed the physical examination data of healthcare workers in the Beijing Chest Hospital from September 2012 to December 2015.Low-dose lung CT examinations were performed in all cases.The comparisons between active and inactive PTB according to the CT findings were made using the Pearson chi-square test or the Fisher’s exact test.Comparisons between the incidences of active PTB in high-risk areas and non-high-risk areas were performed using the Pearson chi-square test.Analyses of active PTB were performed according to different ages,numbers of years on the job,and the risks of the working areas.Active PTB as diagnosed by the LDCT examinations alone was compared with the final comprehensive diagnoses,and the sensitivity and positive predictive value were calculated.Results:A total of 1012 participants were included in this study.During the 4-year period of medical examinations,active PTB was found in 19 cases,and inactive PTB was found in 109 cases.The prevalence of active PTB in the participants was 1.24%,0.67%,0.81%,and 0.53%for years 2012 to 2015.The corresponding incidences of active PTB among the tuberculosis hospital participants were 0.86%,0.41%,0.54%,and 0.26%.Most HCWs with active TB(78.9%,15/19)worked in the high-risk areas of the hospital.There was a significant difference in the incidences of active PTB between the HCWs who worked in the high-risk and non-high-risk areas(odds ratio[OR],14.415;95%confidence interval(CI):4.733-43.896).Comparisons of the CT signs between the active and inactive groups via chi-square tests revealed that the tree-in-bud,cavity,fibrous shadow,and calcification signs exhibited significant differences(P=0.000,0.021,0.001,and 0.024,respectively).Tree-in-bud and cavity opacities suggest active pulmonary tuberculosis,whereas fibrous shadow and calcification opacities are the main features of inactive pulmonary tuberculosis.Comparison with the final comprehensive diagnoses revealed that the sensitivity and positive predictive value of the diagnoses of active PTB based on LDCT alone were 100%and 86.4%,respectively.Conclusions:Healthcare workers in tuberculosis hospitals are a high-risk group for active PTB.Yearly LDCT examinations of such high-risk groups are feasible and necessary.
文摘Background The incidence of thyroid cancer has been increasing.Our aim was to evaluate the efficacy of low-dose dualphase helical computed tomography (CT) in the characterization of thyroid lesions,and to discuss the relationship between image characteristics and their pathology.Methods One hundred and six patients with thyroid lesions underwent low-dose dual-phase helical CT after the injection of contrast material.CT scans were obtained at arterial and venous phase with delays of 25 and 65 seconds,and tube current of 60 and 120 mA,respectively.The attenuation change in the lesion between the arterial and venous phase was analyzed and categorized as "increased," "decreased," "mixed" or "no change." Results Histopathologic diagnosis was obtained by surgery in 106 patients (115 lesions).Of the 106 patients,45 had nodular goiter,5 thyroid adenoma,6 thyroiditis,and 50 papillary thyroid carcinoma (PTC) (59 lesions).The attenuation value showed a significant difference (P <0.05) between the arterial and venous phase for the high attenuation area.There was statistical significant difference in terms of attenuation value in high attenuation areas at both phases and in low attenuation areas on arterial phase between nodular goiter and PTC (P <0.05).However,there was no significant difference in attenuation value between adenoma and PTC.Twenty-nine cases (76.3%) of goiter manifested mixed type,3 cases (3/5) of adenoma showed decreased type,6 cases (6/6) of thyroiditis showed increased type,and 55 cases (93.2%) of PTC showed decreased type attenuation.The sensitivity,specificity for thyroid carcinoma by dual-phase CT were 94.9% and 80.4% respectively.The overall diagnostic accuracy for thyroid lesions by dual-phase CT was 87.8%.Conclusions The performance of dual-phase helical CT is related to the pathological structure of the lesions.The analysis of enhancement patterns by using dual-phase helical CT will be helpful in the differential diagnosis of thyroid lesions.