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Objective:To investigate the application value of spectral computed tomo-graphy (CT) multi-parameter imaging in predicting gastric cancer lymph node metastasis.Methods:The retrospective case-control study was conducted. The clinicopathological data of 86 patients with gastric cancer who were admitted to the First Affiliated Hospital of Zhengzhou University from January 2014 to June 2017 were collected. There were 53 males and 33 females, aged from 22 to 87 years, with a median age of 53 years. All patients received abdominal plain scan and arterial and venous phase contrast spectral scan. Images of plain scan, 70 keV monochromatic and iodine-based images in arterial and venous phase were analyzed on post-processing working station. Observation indicators: (1) gastric cancer lymph node metastasis; (2) analysis of influencing factors for lymph node metastasis in gastric cancer; (3) introduction of special cases. Count data were described as absolute numbers. Univariate analysis was performed using the chi-square test or rank sum test. Multivariate analysis was conducted using the Logistic regression model.Results:(1) Gastric cancer lymph node metastasis: of the 86 patients, 64 cases had lymph nodes metastasis and 22 had no lymph nodes metastasis. (2) Analysis of influencing factors for lymph node metastasis in gastric cancer: results of univariate analysis showed that tumor growth pattern, tumor diameter, infiltration of peritumor fat, CT value in arterial phase, CT value in venous phase, iodine value in venous phase were related factors affecting lymph nodes metastasis in gastric cancer ( χ2=6.753, Z=-3.180, χ2=7.649, Z=-2.051, -2.971, -2.547, P<0.05). Results of multivariate analysis showed that infiltration of peritumor fat and the iodine value in venous phase were greater than 12(100 μg/cm 3) and not greater than 16(100 μg/cm 3), or greater than 16(100 μg/cm 3) were independent risk factors affecting lymph nodes metastasis in gastric cancer ( odds ratio=13.154, 3.761, 7.583, 95% confidence interval as 2.597-66.620, 1.893-8.572, 4.769-16.692, P<0.05). (3) Introduction of special cases: case 1 was male, aged 46 years. Results of preoperative spectral CT enhanced scan showed gastric antrum space occupying lesion combined with enlarged lymph nodes. During enhancement arterial phase, spectral CT 70 keV monochromatic images and corresponding iodine-based images of primary lesion layer in the transverse view showed gastric wall thickening with mild to moderate enhancement, clear fat space in serosa and enlarged lymph nodes in lesser curvature. The spectral CT 70 keV monochromatic images and corresponding iodine-based images below pylorus level in the transverse view showed subpyloric enlarged lymph nodes. During enhancement venous phase, the 70 keV monochromatic images and corresponding iodine-based images of primary lesion layer in the transverse view showed layered enhancement of gastric antrum lesions and mucosal enhancement, with a high iodine value. The patient was diagnosed as gastric antrum cancer with lymph node metastasis, no serosal or peritumoral fat invasion. Results of postoperative pathological examination showed moderately differentiated adenocarcinoma of gastric antrum with serosal invasion and lymph node metastasis. Case 2 was male, aged 53 years. Results of preoperative spectral CT enhanced scan showed gastric cancer of lesser curvature combined with enlarged lymph nodes. During enhancement arterial phase, 70 keV monochromatic images and corresponding iodine-based images of primary lesion layer in the transverse view showed gastric wall heterogeneous thickening of lesser curvature, with moderate enhancement, obscure peritumor fat space, unclear serosa, and multiple enlarged lymph nodes in lesser curvature. During enhancement venous phase, 70 keV monochromatic images in the transverse view showed unclear boundary between lesions and enlarged lymph nodes in lesser curvature, obscure peritumor fat. During enhancement arterial phase, 70 keV monochromatic images of celiac trunk layer in the transverse view showed parasplenic artery lymph nodes, with circular enhancement and no enhancement in central necrotic elements. The patient was diagnosed as gastric cancer of lesser curvature with lymph node metastasis, serosal and peritumor fat invasion. Results of postoperative pathological examination showed poorly differentiated adenocarcinoma of gastric antrum with serosal invasion and lymph node metastasis. Conclusion:The infiltration of peritumor fat and iodine value in venous phase are independent factors affecting gastric cancer lymph node metastasis.
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Objective To investigate the image quality and radiation dose of spectral CT with automatic spectral imaging mode selection (ASIS) and adaptive statistical iterative reconstruction (ASIR) at abdominal CT as compared with low-kVp CT with ASIR.Methods Two hundred patients underwent the plain and arterial-phase (AP) and portal venous-phase (PVP) contrast-enhanced abdominal CT scan were analyzed prospectively.The patients were randomly assigned to the control group (low-kVp CT scan) and study group (spectral CT scan),if BMI ≤ 23.9 kg/m2,patients were assigned into group A (80 kVp) or group B (spectral CT with ASIS);if 24.0 kg/m2 ≤ BMI＜28.9 kg/m2,patients were assigned into group C (100 kVp) or group D (spectral CT with ASIS)(n=50 each).Groups A and B,groups C and D were matched by gender,age,body mass index,cross sectional area and contrast agent dose respectively.Low-kVp images and monochromatic images (40 to 60 keV) were all reconstructed by using ASIR.Radiation dose and quantitative parameters (image noise in HU and contrast-to-noise ratio of the liver,aorta and portal vein) were compared by using t test while overall image quality was assessed by Mann-Whitney U test between the matched groups.Results Radiation dose in the group B was significantly higher than group A (increased by 10％,P＜0.05) but there was no significant differences between groups C and D (P＞0.05).Compared to the control group,image noises in the study group were higher at 40 keV and 50 keV (P＜0.05),but similar at 40 keV (P＞0.05).At the energy level of 40 keV,the study group showed higher CNRs,but lower overall image quality scores than the control group except for the similar image quality scores between groups A and B during AP (P＜0.05).At the energy level of 50 keV,the CNRs and overall image quality scores in the study group were higher than or similar to the control group.At the energy level of 60 keV,the study group showed lower or similar CNRs,but higher or similar overall image quality scores compared with the control group.Conclusions The radiation dose of spectral CT with ASIS technique was slightly higher than 80 kVp CT but similar to 100 kVp CT.By combining ASIR technique,monochromatic image at 50 keV can maintain or improve CNR and overall image quality as compared with low-kVp images.
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Purpose To discuss the value of phase III CT angiography (CTA) and ultrasound in evaluating the preoperative vascular anatomical variation and the lumen patency of the patients with liver transplantation. Materials and Methods The clinical and imaging data of 126 patients with liver transplantation in the First Affiliated Hospital of Zhengzhou University were collected. CT scan in arterial phase, portal venous phase, venous phase and CTAreconstruction and ultrasound examination were performed before surgery. CTA images included volume rendering (VR), maximum intensity projection (MIP), curve plane reformation (CPR), and multi-plane reformation (MPR). The anatomical variations and lumen patency of the hepatic artery, the portal vein system, the hepatic vein and the inferior vena cava were observed. The accuracy of CTA and ultrasound of the evaluation of blood vessels in patients with liver transplantation was compared with the criteria of intraoperative exploration and postoperative pathological results. Results Among 126 patients with liver transplantation, all the hepatic artery lumen was unobstructed, with 98 cases of normal anatomical structure and 28 cases (22.2％) of anatomical variation, including Michel type II 7.1％ (9/126), type III 6.3％ (8/126), type IV 3.2％ (4/126), type V 2.4％ (3/126), type VI 0.8％ (1/126); 2.4％(3/126) of Michel classification was not included. The diagnostic accuracy of CTA for arterial anatomical variations was 100.0％, and the patency diagnosis of the lumen was consistent with the operation, and the anatomical variation cannot be evaluated. In 126 patients, there were 94 cases of portal vein patency, and 32 cases of portal vein embolus, including 21 cases with thrombus and 11 cases with tumor embolus. The diagnostic accuracy of CTA and ultrasound for portal vein embolus was 93.7％ and 96.0％, respectively; and there was no statistical significance (P>0.05). The diagnostic accuracy of them for thrombosis was 96.0％ and 91.3％, respectively; and there was statistical significance (P<0.05). The diagnostic accuracy of them for the tumor thrombus was 97.6％ and 92.1％, respectively; and there was statistical significance (P<0.05), CTA could show the collateral circulation around the portal vein. The diagnostic accuracy of CTA and ultrasound for venous patency was both 99.3％. The diagnostic accuracy of CTA and ultrasound for the anatomy of hepatic venous trunk was 99.2％ and 95.2％, respectively; and there was no statistical significance (P>0.05). Conclusion CTA can accurately evaluate the hepatic artery variation of liver transplantation. It has a high accuracy rate for the qualitative diagnosis of portal vein emboli, and can display collateral circulation. Its overall preoperative diagnostic value is better than that of ultrasound.
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Objective To evaluate the influence of preset adaptive statistical iterative reconstruction-V (ASIR-V) techniques on image quality and radiation dose reduction of abdominal CT in phantom,and to investigate the optimal ASIR-V level.Methods Abdominal anthropomorphic phantom was scanned using Revolution CT,when noise index (NI) were set as 6,8,10,12 and 14,respectively.Then 0-100％ ASIR-V and conventional scan was performed and 55 sets of images were obtained.CT value,noise,subjective score and radiation dose were recorded,and the optimal ASIR-V was obtained.Subjective scores of images in each group were compared using rank sum test,and CT value,noise and radiation dose were compared with one way ANOVA and paired t test.Results The image subjective score unchanged when NI was 6,8 or 10,slightly increased when NI was 12 and 14 with 0-40％ ASIR-V,and decreased above 50％ ASIR-V at all NI.When NI was 6,8 or 10,more than 70％ ASIR-V image subjective score fell below 3 points.When NI was 12 or 14 group,more than 60％ ASIR V subjective score fell below 3 points.The image quality score of conventional scan had no difference with 40％ ASIR-V when NI was 6,8 or 10,respectively (P=0.626,0.915,0.514),and inferior to 40％ ASIR-V when NI was 12 or 14 (P=0.041,0.036),while in all NI group,image quality score of conventional scan was superior to 60％ ASIR-V (P=0.021,0.012,0.015,0.014,0.007).CT values and image noises had no significant differences in different parts in all NI groups (all P＞0.05).CT dose index volume (CTDIvol) continuing decreased with ASIR-V.Compared with that of conventional scan,at 40％,50％ and 60％ ASIR-V,CTDIvol reduced by 49.82％,62.51％ and 71.63％,respectively.Conclusion Preset ASIR-V can reduce radiation dose obviously while maintaining the overall image quality,and 40％-60％ ASIR-V can be recommended for abdominal CT in clinical application.
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Objective To investigate the CT spectral imaging features of benign and malignant ovarian tumors and to assess the value of spectral CT in differentiating between benign and malignant ovarian tumors.Methods This study was granted by the institutional review board with a waiver for informed consent.34 patients with ovarian tumor(11 benign tumors and 23 malignant tumors)underwent preoperative CT scanning that included arterial phase (AP)and venous phase (VP)with GSI mode.Measurements were performed on the GSI viewer.The iodine concentration (IC,100 ug/cm3)was saved,and the normalized iodine concentration (NIC)and the spectral curve(spectral Hounsfield unit curve)were recorded.The slope of the curve was calculated as the formula:(CT attenuation (40 keV)-CT attenuation(100 keV))/60.The CT value was measured at 70 keV in Mono image.CT values,the slope of the spectral curve,the iodine concentration and NIC were compared between the two groups by using independent sample t-test with software SPSS 2 1.0.Receiver operating characteristic (ROC)was used to determine the threshold of slope of the spectral curve,the iodine concentration and NIC for differentiating benign and malignant ovarian tumors in VP.Results The slope of the spectral curve,the iodine concentration and NIC of malignant ovarian tumors in VP were 1.72±0.77,14.50±6.44 (100 μg/cm3),and 0.33±0.12.The slope of the spectral curve,the iodine concentration and NIC of benign ovarian tumors in VP were 1.05±0.48,8.86±4.04 (100 μg/cm3),and 0.22±0.13.Significant differences were found between the slope of spectral curve,the iodine concentration and NIC of the malignant ovarian tumors and those of the benign ovarian tumors in VP (P=0.01).CT values in double phases revealed no difference between these two groups (P>0.05).Conclusion There is a significant difference between the solid component of benign ovarian tumors and that of malignant ovarian tumors in spectral CT.GSI scan mode can provide more information for the differential diagnosis of benign and malignant ovarian tumors.
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Objective To evaluate the CT spectral imaging in assessing the therapeutic efficacy of axitinib in rabbit VX2 liver tumors. Methods Thirty-two VX2 liver tumor-bearing rabbits (diameter 1.0 to 2.5 cm) were prospectively and randomly assigned into the study group (axitinib treated group, n=16) or the control group (pseudo-therapy group, n=16). They were treated with axitinib or saline by using the gastric tube respectively. All the rabbits underwent unenhanced, arterial-phase (AP) and portal-phase (PP) contrast enhanced CT examinations by using spectral CT at different time points (baseline, 2, 4, 7, 10 and 14 days after treatment). Tumor size (TS) at each time point was recorded to calculate the percentage change (ΔTS)after treatment relative to baseline. Iodine concentration (IC) of the entire tumor, the peripheral hypervascular region and the center of the tumor were measured and normalized to aorta (NIC) to generate the difference for the NIC (NICD) between a given time and baseline. The tumorΔTS and NICD between the control and treated groups were compared by using Mann-Whitney U test. Serial changes in NICD at different time points were evaluated by using Wilcoxon signed rank test. Correlations between the NICD andΔTS, between NIC and microvessel density (MVD) were analyzed. Results The tumorΔTS after treatment in the control group and study group increased continuously. The tumorΔTS was significantly smaller in the treated group than that in the control group at day 7, 10 and 14. At day 2 , 4 and 10 after treatment, each tumor NICD in the study group was smaller compared with the control group(P0.05).Conclusion CT spectral imaging allows the evaluation and early prediction of tumor response to axitinib in rabbit VX2 liver tumors.
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<p><b>OBJECTIVE</b>To investigate the preoperative assessment value of spectral CT quantitative parameters in lymph node metastasis of gastric cancer.</p><p><b>METHODS</b>From December 2013 to June 2015, clinical and image data of 86 patients with gastric cancer confirmed by gastroscope pathology undergoing preoperative enhanced CT were prospectively collected. Enhanced CT included nonenhanced CT of conventional 120 kVp mode, arterial phase (AP) and venous phase (VP) with GSI mode on Discover GSI CT scanner. The raw data were transferred to ADW4.6 workstation to reconstruct the monochromatic images at 70 keV and iodine-based images in AP and VP with 1.25 mm thickness. The short diameter, long diameter, ratio of short to long diameter, CT attenuation and iodine value of lymph nodes in each phase were measured and recorded. Pathology results were used as golden standard. The spectral CT quantitative parameters of positive and negative lymph nodes were compared by t test and the sensitivity and specificity analyses were performed by ROC curves. This clinical study registration number 81271573.</p><p><b>RESULTS</b>Among these 86 gastric cancer patients (53 male and 33 female), tumors of 28 cases were in upper part, of 12 cases in middle part, of 27 cases in distal part and of 19 cases involved two parts. Thirty-five cases were differentiated type and 51 cases were undifferentiated type. A total of 1 072 lymph nodes were found in operation, of which 412 nodes were positive and 660 were negative. Among 552 lymph nodes found in CT images, 338 nodes were positive and 214 were negative. Compared to negative lymph nodes, short diameter [(9.52±3.58) mm vs. (6.48±2.94) mm, t=4.639, P=0.000], ratio of short to long diameter (0.82±0.14 vs. 0.61±0.08, t=13.514, P=0.000), CT attenuation in precontrast [(20.44±6.77) Hu vs. (16.06±7.14) Hu, t=3.154, P=0.002], CT attenuation in AP[(61.71±11.78) Hu vs. (40.11±10.18) Hu, t=9.588, P=0.000], CT attenuation in VP[(71.34±13.03) Hu vs. (53.81±11.39) Hu, t=7.888, P=0.000], iodine value in AP [(16.17±4.22) 100 μg/cmvs. (8.03±3.10) 100 μg/cm, t=9.781, P=0.000], the iodine value in VP [(20.13±6.04) 100 μg/cmvs. (11.58±4.13) 100 μg/cm, t=10.147, P=0.000] of positive lymph nodes were greater. The long diameter was not significantly different between positive and negative lymph nodes [(11.71±5.63) mm vs. (10.64±3.20) mm, t=1.380, P=0.169]. The area under ROC curve of short diameter, ratio of short to long diameter, CT attenuation in precontrast, AP and VP, iodine value in AP and VP of lymph nodes was 0.600, 0.880, 0.648, 0.832, 0.755, 0.864, 0.835, respectively. Taking the ratio of short to long diameter over 0.72 as diagnosis standard, the sensitivity was 75.6% and the specificity was 93.5%. Taking the CT number in AP over 49.75 Hu, the sensitivity was 66.9% and the specificity was 88.8%. Taking the CT number in VP over 59.80 Hu, the sensitivity was 69.9% and the specificity was 77.6%. Taking the iodine value in AP over 9.65 (100 μg/cm), the sensitivity was 80.4% and the specificity was 82.2%. Taking the iodine value in VP over 15.65 (100 μg/cm), the sensitivity was 69.9% and the specificity was 86.9%. Combinong the ratio of short to long diameter with the iodine value in AP, the sensitivity was 95.2% and the specificity was 76.9%.</p><p><b>CONCLUSIONS</b>The ratio of short to long diameter, the iodine value and CT attenuation in AP and VP of lymph nodes in spectral CT are important criteria to evaluate the metastasis of gastric cancer. Combining the ratio of short to long diameter with the iodine value in AP can obviously improve the sensitivity.</p>
Subject(s)
Female , Humans , Male , Gastroscopy , Iodine Radioisotopes , Lymph Nodes , Diagnostic Imaging , Pathology , Lymphatic Metastasis , Diagnostic Imaging , ROC Curve , Sensitivity and Specificity , Stomach Neoplasms , Diagnostic Imaging , Tomography, X-Ray Computed , MethodsABSTRACT
Objective To investigate the image quality and radiation dose of automatic spectral imaging mode selection and adaptive statistical iterative reconstruction (ASIR) at abdominal CT with low contrast agent dose. Methods One hundred cases with the arterial-phase (AP) and portal venous phase (PVP) contrast-enhanced abdominal CT scanning were analyzed prospectively. Patients were randomly assigned to the study group and control group (n=50 each). In the study group, automatic spectral imaging mode selection and contrast agent dose of 300 mg/kg were used and spectral monochromatic images(40 to 60 keV) were reconstructed using either filtered back-projection (FBP) (group A) or ASIR (group B). In the control group, the fixed tube potential of 120 kVp and contrast agent dose of 450 mg/kg were used with images reconstructed using FBP (group C). Quantitative parameters (image noise and contrast-to-noise ratio of the liver, pancreas, aorta and portal vein) and qualitative visual parameters (overall image quality as graded on a 5-point scale) were compared among the groups by using One-way ANOVA or Kruskal-Wallis H test. Two sample t tests were used compare the radiation dose difference. Results There had no significant difference in CTDIvol[both (12±5) mGy] and DLP[(364±142) mGy·cm versus (377±131) mGy·cm] between the study group and control group(t=-0.408 and-0.428,P>0.05). During the AP and PVP, at the energy level of 40 keV, group B showed higher CNRs than group A and group C, lower image noise[ (29±6) HU in AP, (24±6) HU in PVP] than group A[(43±11) HU, (44±10) HU] but higher image noise than group C[ (18± 4) HU, (18±4) HU], lower overall image quality scores[(3.0±0.2) point, (2.9±0.3) point] than group C[(3.6± 0.4) point , (3.6±0.5) point] but similar scores to group A[(2.9±0.4) point,(2.8±0.4)point]. At the energy level of 50 keV, group B showed higher CNRs than group A but higher than or similar CNRs to group C, lower image noise[ (20±5) HU, (20±4) HU] than group A[(31±8) HU, (31±7) HU] but similar image noise to group C, higher overall image quality scores[(3.6±0.4) point, (3.5±0.4) point]than group A[(3.3±0.3) point,(3.3±0.3) point] but similar scores to group C. At the energy level of 60 keV, group B showed lower image noise[(14±4) HU, (14±3) HU], higher CNRs and overall image quality scores[(3.9±0.4) point,(3.9±0.3) point] than group A[(19 ± 5) and (20 ± 5)HU in image noise, (3.7 ± 0.4) and (3.7 ± 0.3) point in overall image quality scores ]and group C. Except for monochromatic images at 40 keV, the overall image quality scores in group B were all greater than 3 point and met the clinical diagnostic level. Conclusions The radiation dose of CT spectral imaging and conventional 120 kVp CT scan is equivalent with the use of automatic spectral imaging mode selection. By combining ASIR technique, monochromatic images at 50 and 60 keV can improve CNR and reduce contrast agent dose while maintain or improve overall image quality.
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<p><b>OBJECTIVE</b>To investigate the application value of spectral CT in the differentiation of stage T3 and T4a gastric carcinoma.</p><p><b>METHODS</b>Data of 62 gastric cancer patients of stage T3 and T4a undergoing abdominal spectral CT examination in the First Affiliated Hospital of Zhengzhou University from December 2013 to December 2014 were collected retrospectively. There were 38 male and 24 female patients, with age of 33 to 77(58.6±10.4) years old. Abdominal double-phase enhanced scanning in gemstone spectral imaging mode was used to measure Iodine concentration (IC, 100 μg/ml) and water concentration(WC, 100 μg/ml) of perigastric fat tissue adjacent to the lesion during arterial phase(AP) and venous phase(VP), and normalized iodine concentration (nIC) was calculated respectively(nIC=IC/IC of aorta on the same slice). IC, WC, nIC of arterial phase and venous phase between stage T3 and T4a lesions were compared with double independent sample t test and compared with pathology. The diagnostic efficacy was evaluated using receiver operating characteristic (ROC) curve analysis.</p><p><b>RESULTS</b>During arterial phase in stage T4a cases, IC (100 μg/ml) was -5.19±0.81 and nIC was -0.05±0.01, which was significantly higher than -3.44±1.54 (P=0.000) and -0.03±0.01 (P=0.000) in stage T3 cases. During venous phase in T4a cases, IC (100 μg/ml) was -3.78±0.94 and nIC was -0.04±0.01, which was significantly higher than -1.62±1.43 (P=0.000) and -0.02±0.02 (P=0.000) in stage T3 cases. As compared to arterial phase, IC and nIC of stage T4a and T3 of venous phase were more significantly different (all P<0.05). WC of stage T4a during arterial and venous phase was 955.72±15.68 and 949.86±17.36 respectively, while WC of stage T3 during arterial and venous phase was 947.77±18.43 and 942.46±18.53 respectively. There were no significant differences in WC between two stage cases during arterial and venous phase (P=0.106, P=0.143). ROC analysis showed that area under the ROC of IC and nIC during arterial phase was 0.829 and 0.867 respectively, and cut-off value of nIC was -0.039 for differentiation of stage T3 and T4a with corresponding 83.3% of sensitivity and 75.0% of specificity; area under the ROC of IC and nIC during venous phase was 0.873 and 0.905 respectively, and cut-off value of nIC was -0.031 for differentiation of stage T3 and T4a with corresponding 81.0% of sensitivity and 85.0% of specificity.</p><p><b>CONCLUSIONS</b>Abdominal spectral CT scan is useful in the differentiation of stage T3 and T4a gastric carcinoma. The IC of perigastric fat tissue is significantly higher in stage T4a gastric carcinoma compared to stage T3 gastric carcinoma. Higher diagnostic efficacy can be obtained when taking -0.031 as the cut-off value of nIC during venous phase.</p>