The aortic and hepatic contrast enhancement at CT and its correlations with various body size index / 中华放射学杂志

Objective@#To evaluate the effect of height (HT), total body weight (TBW), body mass index (BMI), lean body weight (LBW), body surface area (BSA) and blood volume (BV) on aortic and liver contrast enhancement during upper abdominal contrast-enhanced CT scans.@*Methods@#One hundred and thirteen enrolled patients underwent upper abdominal multiphase contrast-enhanced CT scans. The enhancement (ΔHU) of aorta in hepatic arterial phase and liver parenchyma in portal venous phase were measured and calculated. The ΔHU values difference of aorta and liver parenchyma in subgroups between males and females, TBW<60 kg and TBW≥60 kg, BMI<25 kg/m2 and BMI≥25 kg/m2 were compared. To evaluate the effect of the patient′s body parameters on aortic and hepatic enhancement, we performed simple linear regression analyses between the change in CT numbers per gram of iodine (ΔHU/gI) at aorta and liver and each of the following: HT, TBW, BMI, LBW, BSA, and BV. Pearson and t test were used.@*Results@#The mean ΔHU values of aorta and liver were significantly lower at males than that of at females (P<0.05). They were higher at TBW<60 kg patients than at TBW≥60 kg patients(P<0.05), and the mean ΔHU values of the liver at BMI<25 kg/m2 patients were significantly higher than at BMI≥25 kg/m2 patients(P<0.05). The proportion of the ΔHU values at liver less than 50 HU was higher at males (18.3%, 11/60) than at females (7.5%, 4/53). The most obvious negative correlation coefficients were found between the ΔHU/gI of aorta and LBW at hepatic arterial phase (r=-0.559, P<0.01), and between the ΔHU/gI of liver and BSA at portal venous phase (r=-0.680, P<0.01).@*Conclusion@#LBW or BSA could be the alternative body index to TBW for the calculation of personalized iodine dose protocol at aortic and liver enhanced CT scans.

The value of multi-parametric MRI radiomics in the prediction of neoadjuvant therapy for rectal mucinous adenocarcinoma / 中华放射学杂志

Objective:To investigate the application value of baseline MRI multi-parametric imaging radiomics in prediction of neoadjuvant chemoradiotherapy (NCR) efficacy of rectal mucinous adenocarcinoma (RMAC).Methods:Retrospective analysis was performed in the Sixth Affiliated Hospital of Sun Yat-sen University from August 2012 to October 2018. A total of 79 patients were included in this study, including 52 males and 27 females, aged 20-78 years (median age 52 years). According to the classification criteria of pathological regression, all patients were divided into NCR responsiveness group ( n=31) and nonresponsiveness group ( n=48). And 701 imaging features of T 2WI, diffusion weighted imaging (DWI) and enhanced T 1WI images of baseline MRI were extracted, and feature subsets were selected by repeatability analysis and feature dimensionality reduction to construct the radiomics prediction model. The tumor features from baseline MRI between the NCR responsiveness group and the nonresponsiveness group were compared, and the features of P<0.05 were combined with the radiomics to construct a model. Using pathology as the gold standard, the receiver operating characteristic (ROC) curve was used to evaluate the diagnostic efficiency of the prediction model, and the area under the curve (AUC), 95% confidence interval, sensitivity and specificity were calculated, and the DeLong test was used to compare the diagnostic efficacy of different prediction models. Results:By comparing the conventional tumor imaging characteristics of the NCR responsiveness group and the nonresponsiveness group, the differences in lymph node stage and mucinous nodule status between the two groups were statistically significant (χ2 =6.040, 5.870, P<0.05). The AUC of ROC curves based on T 2WI, DWI, and enhanced T 1WI radiomics were 0.816, 0.821, and 0.819, respectively, which were higher than those of conventional tumor characteristics (lymph node staging, mucinous nodule status) (AUC=0.607), and the differences were statistically significant ( Z=-2.391, -2.580 and -2.717, P<0.05). Among the joint prediction models of T 2WI, DWI and contrast-enhanced T 1WI radiomics and conventional tumor features, the DWI combined model had the largest AUC (0.843), and there was no statistically significant difference between the three combined models (all P>0.05). Conclusion:The baseline T 2WI, DWI, and contrast-enhanced T 1WI radiomics model can be used to predict the NCR efficacy of RMAC, which is better than the predictive efficacy of conventional features, and the combination with conventional features can further improve the predictive efficacy.

The aortic and hepatic contrast enhancement at CT and its correlations with various body size index / 中华放射学杂志

Objective:To evaluate the effect of height (HT), total body weight (TBW), body mass index (BMI), lean body weight (LBW), body surface area (BSA) and blood volume (BV) on aortic and liver contrast enhancement during upper abdominal contrast-enhanced CT scans.Methods:One hundred and thirteen enrolled patients underwent upper abdominal multiphase contrast-enhanced CT scans. The enhancement (ΔHU) of aorta in hepatic arterial phase and liver parenchyma in portal venous phase were measured and calculated. The ΔHU values difference of aorta and liver parenchyma in subgroups between males and females, TBW<60 kg and TBW≥60 kg, BMI<25 kg/m 2 and BMI≥25 kg/m 2 were compared. To evaluate the effect of the patient′s body parameters on aortic and hepatic enhancement, we performed simple linear regression analyses between the change in CT numbers per gram of iodine (ΔHU/gI) at aorta and liver and each of the following: HT, TBW, BMI, LBW, BSA, and BV. Pearson and t test were used. Results:The mean ΔHU values of aorta and liver were significantly lower at males than that of at females ( P<0.05). They were higher at TBW<60 kg patients than at TBW≥60 kg patients( P<0.05), and the mean ΔHU values of the liver at BMI<25 kg/m 2 patients were significantly higher than at BMI≥25 kg/m 2 patients( P<0.05). The proportion of the ΔHU values at liver less than 50 HU was higher at males (18.3%, 11/60) than at females (7.5%, 4/53). The most obvious negative correlation coefficients were found between the ΔHU/gI of aorta and LBW at hepatic arterial phase ( r=-0.559, P<0.01), and between the ΔHU/gI of liver and BSA at portal venous phase ( r=-0.680, P<0.01). Conclusion:LBW or BSA could be the alternative body index to TBW for the calculation of personalized iodine dose protocol at aortic and liver enhanced CT scans.

Comparative study among total body weight,lean body weight and body surface area adj usted iodine contrast agent dose protocols on liver enhanced CT scans / 实用放射学杂志

Objective To explore the optimal body size index for the calculation of iodine contrast agent dose required for multiphase liver enhanced CT scans based on the total body weight (TBW),lean body weight (LBW)and body surface area (BSA).Methods Two hundred and twenty enrolled patients were randomly divided into three groups,TBW-group (n＝75),LBW-group (n＝72)and BSA-group (n＝73),and administrated iodine doses were 600 mg I/TBW(kg),780 mg I/LBW(kg)and 22 g I/BSA(m2 ),respectively.All patients had taken upper abdominal plain scans and triple-phase enhanced CT scans.The enhanced values (ΔHU)of the aorta at hepatic arterial phase (HAP),the portal vein and liver parenchyma at portal venous phase (PVP)were compared.The correlation coefficients of adjusted maximal hepatic enhancement(aMHE)with TBW,LBW and BSA in three groups were evaluated,respectively.Results There were no statistical differences in the ΔHU values of the aorta at HAP and the portal vein and liver parenchyma at PVP in the three groups respectively.The smallest variances of the aorta at HAP,the portal vein and liver parenchyma at PVP were found in the LBW group. The aMHE showed mildly positive correlation with TBW (r＝0.230)with a P value of 0.047,but it was consistent with LBW (r＝0.158)and BSA (r＝－0.1 54)with corresponding P values of 0.1 85 and 0.1 9 2 ,respectively.Conclusion Compared with TBW and BSA,iodine contrast agent dose calculated based on the patient’s LBW can improve the patient-to-patient uniformities on aorta,portal vein and liver enhancement during the liver multiphase enhanced CT scans.The LBW is the best body index for the calculation of iodine dose on liver enhanced CT scans.

Effects of different wavelet filters on correlation and diagnostic performance of radiomics features / 中南大学学报(医学版)

To investigate the effects of different wavelet filters on correlation and diagnostic performance of radiomics features.
 Methods: A total of 143 colorectal cancer (CRC) patients (64 positive in lymph node metastasis and 79 negative) with contrast-enhanced CT examination were recruited. After labeling the tumor area by experienced radiologists, radiomics wavelets features based on 48 different wavelets were extracted using in-house software coded by Matlab. The correlation coefficients of the features with same names between different wavelets were calculated and got the distribution of high-correlation features between each wavelet. The least absolute shrinkage and selection operator (LASSO) was used to build signatures between lymph node metastasis and wavelet features data set based on different wavelets. The numbers of features in signatures and diagnostic performance were compared using Delong's test.
 Results: With the difference of wavelet order increased, the number of high-correlation features between two wavelets decreased. Some features were prone to high correlation between different wavelets. When building radiomics signature based on single wavelet, signatures built from 'rbio2.2', 'sym7' and 'db7' did well in predicting lymph node metastasis. The signature based on Daubechies wavelet feature set had the highest performance in predicting lymph node metastasis, while the signature from Biorthogonal wavelet features was worst. Improvement was significant in diagnostic performance after excluding the high-correlation features in the whole features set (P=0.004).
 Conclusion: In order to reduce the data redundancy of features, it is recommended to select wavelets with large differences in wavelet orders when calculating radiomics wavelet features. It is necessary to remove high correlation features for improving the diagnostic performance of radiomics signature.

CT-based radiomics analysis for evaluating the differentiation degree of esophageal squamous carcinoma / 中南大学学报(医学版)

To build a CT-based radiomics predictive mode to evaluate the differentiation degree of the esophageal squamous carcinoma.
 Methods: A total of 160 patients with surgical pathology, complete clinical data and chest CT scanning before operation were retrospectively collected from January 2008 to August 2016. All patients were assigned randomly to a primary data set and an independent validation. Texture analysis was performed on CT images, while the carcinomas were performed by manual segmentation to extract the radiomics features. Radiomics features were extracted and 9 radiomics signatures were finally selected after dimension reduction. Radiomics features were extracted and established via Matlab. Multivariable logistic regression analysis was performed to build the predictive model. A 10-fold cross-validation was used for selecting parameters in the least absolute shrinkage and selection operator (LASSO) model by minimum criteria. The receiver operating characteristic (ROC) curves and areas under ROC curve (AUC) were used to compare the model performance in the primary validation and the independent validation for evaluating the differentiation degree of esophageal squamous carcinoma.
 Results: Radiomics signature showed great effect in discriminating primary data set and independent validation. The predictive model had a good performance in primary data set. The AUC was 0.791, the sensitivity was 81.6%, and specificity was 72.3%. In the independent validation, the AUC was 0.757, the sensitivity was 70.0%, and the specificity was 73.0%.
 Conclusion: The predictive model can be used for evaluating the differentiation degree of esophageal squamous carcinoma efficiently, which can be helpful to clinicians in diagnosis and choice of treatment for esophageal squamous carcinoma.

Preoperative evaluation of histologic grade in invasive breast cancer with T2W-MRI based radiomics signature / 中南大学学报(医学版)

To develop and validate a fat-suppressed (T2 weighted-magnetic resonance imaging, T2W-MRI) based radiomics signature to preoperatively evaluate the histologic grade (grade I/II VS. grade III) of invasive breast cancer.
 Methods: A total of 202 patients with MRI examination and pathologically confirmed invasive breast cancer from June 2011 to February 2017 were retrospectively enrolled. After retrieving fat-suppressed T2W images and tumor segmentation, radiomics features were extracted and valuable features were selected to build a radiomic signature with the least absolute shrinkage and selection operator (LASSO) method. Mann-Whitney U test was used to explore the correlation between radiomics signature and histologic grade. Receiver operating characteristics (ROC) curve was applied to determine the discriminative performance of the radiomics signature [area under curre (AUC), sensitivity, specificity, and accuracy]. An independent validation dataset was used to confirm the discriminatory power of radiomics signature. 
 Results: Eight radiomics features were selected to build a radiomics signature, which showed good performance for preoperatively evaluating histologic grade of invasive breast cancer, with an AUC of 0.802 (95% CI 0.729 to 0.875), sensitivity of 78.7%, specificity of 70.3% and accuracy of 73.7% in training dataset and AUC of 0.812 (95% CI 0.686 to 0.938), sensitivity of 80.0%, specificity of 73.3% and accuracy of 76.0% in the validation dataset.
 Conclusion: The fat-suppressed T2W-MRI based radiomics signature can be used to preoperatively evaluate the histologic grade of invasive breast cancer, which may assist clinical decision-maker.

Correlation of radiomic features based on diffusion weighted imaging and dynamic contrast-enhancement MRI with molecular subtypes of breast cancer / 中华放射学杂志

Objective To explore the relationship between radiomics signatures based on DWI and dynamic contrast-enhanced MRI (DCE-MRI) and molecular subtypes of breast cancer.Methods A retrospective analysis of 79 female breast cancer patients, with single mass, clear molecular subtypes and preoperative breast MRI scanning (obtaining DCE-MRI and ADC images), of Guangdong General Hospital from June 2015 to June 2016,were performed.Traditional quantitative parameters,including ADC value and initial enhancement rate(IER),were recorded.Texture analysis were performed on ADC map and DCE map, with manual segmentation and extraction of radiomic features,and Manual segmentation was performed on ADC map and DCE map, radiomics features were extracted and 10 radiomics signatures were finally selected after dimension reduction. Four molecular subtypes of breast cancer were classified by immunohistochemical detection of pathological specimens, including Luminal A, Luminal B, human epidermal growth factor receptor 2 (HER2) overexpression and triple negative (TN). Univariate logistic regression analysis was used for assessing the performance of ADC values, IER values and radiomics signatures to independently predict molecular subtypes groups.Multivariate logistic regression analysis was performed to establish predicting models, then receiver operating characteristic curves (ROC) were drawn and areas under ROC curve were calculated to compare the diagnostic performance of each model. The Hosmer-Lemeshow test was performed to test the goodness of model fitness. Results There were 29 cases of Luminal A, 39 cases of Luminal B, 5 cases of HER2 overexpression and 6 cases of TN breast cancer patients.Univariate logistic regression analysis was used to assess the ability of traditonal MRI parameters of ADC and IER values and ten of the radiomics siganitures in classifying molecular subtypes,results showed that the AUC values of ADC and IER values, were both less than 0.70 (range 0.516 to 0.605), which indicated valueless;at least one radiomic signature had AUC greater than 0.70 when identifying each molecular subtype, and AUC of DCE_L_G_2.5_autocorrelation achieved the highest value of 0.941 in identifying TN and non-TN subtypes.Multivariate logistic regression analysis were performed to obtain the best model, results showed that the AUCs for classifying Luminal A and non-Luminal A, Luminal B and non-Luminal B, TN and non-TN subtypes were 0.786 and 0.733 And 0.941, respectively. The Hosmer-Lemeshow test showed that the P values of all models were larger than 0.10 (0.156, 0.204 and 0.820,respectively),indicating that there was no significant difference between the predicted and observed values of each model established, these models were all fitted good. Conclusion The radiomics features based on ADC map and DCE map can help to identify the molecular subtypes of breast cancer,especially for the identification of TN type breast cancer.

The value of cardiac MRI in diagnosis of Ebstein anomaly / 中华放射学杂志

Objective To evaluate the value of cardiac MRI in the diagnosis of Ebstein anomaly (EA). Methods Twenty patients from February 2014 to April 2017 with EA confirmed by surgery were enrolled into this study. The analysis in all patients was made according to preoperative cardiac MRI, 2D TTE and surgical data, including the changes of tricuspid valve leaflets, Carpentier classification, the size and function of atrioventricle, late Gadolinium enhancement, the total right/left-volume index and cardiopulmonary bypass time,etc.The numbers of apicaldisplaced leaflets and development condition of all the leaflets were compared using the R×C χ2among the three groups.With surgical results as the reference standard, the diagnostic accuracy of the two groups for the development condition of all the leaflets were evaluated. One-way ANOVA was performed to compare the differences of the apicaldisplaced distance of septal leaflet, using these three methods. Comparisons of the total right/left-volume index, surgery-related data between patients with or without late gadolinium enhancement were performed by independent t test.Results (1) The results in anatomicalstructures, such as distance of apicaldisplacedseptal leaflet,displacement of each leaflet and the Carpentier classification, showed nostatistical difference among MRI,2D TTE and operational findings. The leaflet dysplasia defined by MRI and 2D TTE areequivalent to surgically defined severe dysplasia, and surgically defined mild to moderate dysplasia can't be identified by the former two methods. The overall diagnostic accuracy of MRI and 2D TTE to identify leaflet dysplasia were 41.3%(19/46) and 34.7%(16/46), respectively.(2) Functional right ventricular volume index decreased in 1 case, normal in 8 cases, increased in 11 cases;functional right ventricula rejection fraction decreased in 15 cases. Six patients' left ventricular volume index decreased, 13 remained in normal range, 1 showed increased;left ventricula rejection fraction decreased in 14 cases. (3)LGE was identified in 8 patients and non-LGE in 12. Difference of the total right/left-volume index [(7.12 ± 4.06) vs. (3.84 ± 2.10), P=0.029] between two groups was statistically significant. However, there was no statistical difference in extracorporeal circulation time, aorticcross-clamping time, intubation time, ICU residence time and postoperative hospital staybetween the LGE and non-LGE groups.Conclusions Cardiac MRI can relatively accurately evaluate the apicaldisplacement of leaflets and the morphological changes of the atria and ventricles, as well as quantitatively evaluate the ventricular function, which can rovide references for clinical diagnosis and severity evaluation of EA.

Development and validation of a multivariate risk model for distant metastasis of advanced nasopharyngeal carcinoma / 南方医科大学学报

OBJECTIVE@#To develop a model based on the clinical variables for evaluating the risk of distant metastasis in patients with advanced nasopharyngeal carcinoma (NPC).@*METHODS@#From September,2007 to June,2015,a total of 238 consecutive patients with biopsy-proven NPC in stage Ⅲ-Ⅳ(M0) based on the AJCC TNM staging manual were enrolled in this study,including 106 male and 34 female patients with a median age of 45 years (range 18-68 years).In this cohort,126 patients received concurrent chemoradiotherapy,and 24 received chemotherapy and radiotherapy,and 40 had induction chemotherapy.We used the least absolute shrinkage and selection operator (LASSO) method to select the most significant features for establishing the model for assessing the risks of distant metastasis.@*RESULTS@#Among the 18 clinical variables tested,5 were significantly associated with distant metastasis in advanced NPC,including plasma Epstein-Barr virus (EBV) DNA,neutrophil/lymphocytes (NLR),VCA-IgA,concurrent chemoradiotherapy,and induction chemotherapy.Based on these 5 clinical variables,we established the following model:risk score=1.73×EBV DNA+0.54×NLR+0.38×VCA-IgA-0.95×concurrent chemoradiotherapy-2.37×induction chemotherapy+0.51.The cutoff point of this model was-0.62,which classified the patients into high-risk and low-risk groups for distant metastasis.This model showed a good performance in predicting distant metastasis in patients with advanced NPC (<0.01).@*CONCLUSIONS@#The model we established herein can be used for evaluating the risks of distant metastasis in patients with advanced NPC and provides assistance in the clinical decision-making on individualized treatment strategy.

Promoting translational research of radiomics / 中国医学影像技术

As one the research hotspots in recent years,radiomics,allowing a high-throughput extraction of quantitative imaging features from medical imaging with computer software,has the promising potential in assisting individualized treatment for tumor patients.Though radiomics could quantify the heterogeneity of tumor and show potential values in clinical decision making to promote precision medicine for tumor patients,there are still lots of challenges in clinically translational research of radiomics.Thus,a joint effort should be made by researchers to promote the clinical application of radiomics to assist personalized management for patients.

A CT-based radiomics analysis for clinical staging of non-small cell lung cancer / 中华放射学杂志

Objective To develop and validate a CT-based radiomics predictive model for preoperative predicting the stage of non-small cell lung cancer (NSCLC). Methods In this retrospective study, 657 patients with histologically confirmed was collected from October 2007 to December 2014.The primary dataset consisted of patients with histologically confirmed NSCLC from October 2007 to April 2012, while independent validation was conducted from May 2012 to December 2014.All the patients underwent non-enhanced and contrast-enhanced CT images scan with a standard protocol. The pathological stage (PTNM) of patients with NSCLC were determined by the intraoperative and postoperative pathological findings,and were divided into early stage(Ⅰ,Ⅱstage)and advanced stage(Ⅲ,Ⅳstage).A list of radiomics features were extracted using the software Matlab 2014a and the corresponding radiomics signature was constructed. Multivariable logistic regression analysis was performed with radiomics signature and clinical variables for developing the prediction model. The model performance was assessed with respect to discrimination using the area under the curve (AUC) of receiver operating characteristic(ROC) analysis. Results The discrimination performance of radiomics signature yielded a AUC of 0.715[95% confidence interval (CI):0.709 to 0.721] in the primary dataset and a AUC of 0.724(95% CI:0.717 to 0.731) in the validation dataset. On multivariable logistic regression, radiomics signature, tumor diameter, carcinoembryonic antigen (CEA) level, and cytokeratin 19 fragment (CYFRA21-1) level were showed independently associated with the stage ( Ⅰ,Ⅱ stage vs. Ⅲ, Ⅳ stage) of NSCLC. The prediction model showed good discrimination in both primary dataset (AUC=0.787, 95%CI:0.781 to 0.793;sensitivity=73.4%, specificity=72.2% ,positive predictive value=0.707,negative predictive value=0.868) and independent validation dataset (AUC=0.777, 95% CI:0.771 to 0.783,sensitivity=91.3% ,specificity=67.3% ,positive predictive value=0.607, negative predictive value=0.946). Conclusion The radiomics predictive model, which integrated with the radiomics signature and clinical characteristics can be used as a promising and applicable adjunct approach for preoperatively predicting the clinical stage (Ⅰ,Ⅱ stage vs. Ⅲ,Ⅳ stage) of patients with NSCLC.

Analysis of CT and MRI signs of hepatic eosinophilic infiltration / 中华放射学杂志

Objective To study and analyze the CT and MRI findings of hepatic eosinophilic infiltration. Methods Twenty nine patients of hepatic eosinophilic infiltration who were confirmed by biopsy or clinical diagnosis were retrospectively analyzed. All the patients underwent CT and/or MRI scan. Twenty seven cases underwent upper abdominal CT plain scan and three phase enhanced scan, and 5 cases underwent upper abdominal MR plain scan and three phase enhanced scan, of which 3 cases underwent CT and MRI scan. Evaluations were made regarding to the numbers of lesion, distribution, size, shape, margin, density or signal characteristic, enhancement parttern and other special features. Pearson correlation analysis was used to analyze the correlation between the number of hepatic lesions and the number of eosinophils in peripheral blood. Results A total of 108 lesions of eosinophilic hepatic infiltration were observed in 29 cases, including 2 cases with single lesion and 27 cases with multiple lesions. Ninety five of the lesions were located in subcapsular parenchyma or surrounding the portal vein. Most subcapsular lesions were wedge-shaped(n=28). Lesions surrounding portal vein were round-shaped(n=32), while the hepatic parenchymal lesions were irregular or round-shaped(n=13). The mean size of lesion was 34 mm, ranging from 3 to 61 mm. The margin of all the lesions were obscure. The lesions showed slightly low density or isodensity on CT pre-contrast images. On MR pre-contrast images, lesions showed slightly low signal or isointense on T1WI, and hyperintense on T2WI. Branches of portal vein were found infilrated by all lesions. Tueleve cases showed“stripe sign”along the portal vein branches, 16 cases showed“halo ring sign”around the portal vein. Pearson analysis indicated a significant correlation between the number of eosinophilic hepatic infiltrated lesions and the increase of eosinophils in peripheral blood (r=0.783, P<0.05). Conclusion The imaging features of EHI had certain characteristics, especially in the three phase dynamic enhanced scanning, from which we can mainly find“progressive enhancement”,“portal vein sign”,“stripe sign”and“halo ring sign”.

The effects of reproducibility of apparent diffusion coefficient measurements obtained with respiratory motion compensation techniques / 中华放射学杂志

Objective To evaluate the reproducibility of normal liver ADC measurements by different respiratory motion compensation techniques. Methods A total of 31 young healthy volunteers who are 20 to 40 years old without any hepatic diseases were selected to research. Each volunteer underwent liver DWI twice in 24 hours with the same parameters and location. The imaging was performed with free-breath(FB), breathhold(BH), rspiratory-triggered(RT)and navigator-triggered(NT)techniques, and the ADC values of the left hepatic lobe and right hepatic lobe (upper, middle and lower) was acquired with two scans. Analysis the the ADC values of various anatomic locations of liver with two-way analysis of variance of randomized block design. Reproducibility of ADCs was assessed with the Bland-Altman method. Analysis of variance and paired-sample t test was used to assess ADCs from both right and left liver lobe among the four techniques. Result The ADC values acquired from the four techniques were significant differences (P<0.01),and the ADC values of the right lobe were less than the left lobe's(P<0.01). It showed a trend to decrease moving from superior to inferior levels in both left and right lobes, and the ADC values among The middle and lower were significant differences (P<0.01). The limit of agreement of ADC of twice imaging among the four techniques were as follow: the right lobe was less than the left lobes, and the breathhold was less the others. As the result, reproducibility in the right liver lobe was better to that in the left and the reproducibility with breathhold was better than the other respiratory motion compensation techniques. Conclusions Both anatomic location and DWI technique influence the liver ADC measurements and their reproducibility. The reproducibility of BH is the best.

Effect of image registration on free breathing MR diffusion kurtosis imaging in normal human kidney / 中华放射学杂志

Objective To investigate the effect of image registration on quantitative measurements of free breathing diffusion kurtosis imaging (DKI) in normal human kidney. Methods Twenty healthy volunteers were prospectively enrolled to undergo DKI imaging with a 3.0 T MR scanner. Three b values (0, 500, and 1 000 s/mm2) were adopted,with image registration performed after image acquisition. Acquired images were fitted using the DKI fitting model to generate the DKI metric maps,which were performed on both the pre-registration images and post-registration images. Image quality of the derived metric maps (before and after image registration,respectively) was assessed by two radiologists. Measurements of fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (D|), axial diffusivity (D⊥), mean kurtosis (MK), radial kurtosis (K|) and axial kurtosis (K⊥) were conducted. The inter-observer reproducibility of the image quality assessment was analyzed using intra-class correlation coefficient(ICC). Wilcoxon signed-rank test was used to evaluate the difference in the subjective scores of the metric maps between those obtained before registration and those after registration. While paired t test or Wilcoxon signed-rank test was performed to analyze the difference in the quantitative measurements of DKI metrics of the renal cortex and medulla between those obtained before registration and those after registration.Results For the inter-observer reproducibility, satisfactory ICCs were obtained for the quantitative metric measurements (pre-registration:0.784 to 0.821;post-registration:0.836 to 0.934). Significant difference was notice between subjective scores for the quality of metric maps (P<0.05 for each comparison). In both the renal cortex and medulla, significant difference was noticed between each metric value obtained with pre-registration images and that with post-registration images (P<0.05 for each comparison). Conclusion Image registration can not only offer higher quality DKI metric maps,but also has effect on the quantitative measurements of obtained metric maps.

Image Quality of Contrast-enhanced Hepatic CT Using Iterative Reconstruction Technique at Different Radiation Doses / 中国医学影像学杂志

Purpose To compare the image quality of contrast-enhanced hepatic CT using iterative reconstruction technique (IMR) at different radiation doses, and to explore the value of IMR in contrast-enhanced hepatic CT under different radiation doses. Materials and Methods Fifty-four cases undergoing contrast-enhanced hepatic CT were divided into two groups using different portal-venous phase protocols:29 cases in group A (120 kV, 250 mAs), 25 cases in group B (80 kV, 500 mAs). Portal venous phase CT images were reconstructed using IMR and filtered back projection to obtain 4 data sets:group A1 (120 kV, FBP), group A2 (120 kV, IMR), group B1 (80 kV, FBP) and group B2 (80 kV, IMR). Images were evaluated for noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) as well as low contrast detectability (LCD), image distortion (ID) and diagnostic confidence (DC). Effective radiation dose was recorded. Results The effective radiation dose in group B was 42.7%, lower than that in group A (t=15.27, PB2>A1>B1 (χ2=58.21, PB1>A2>B2 (χ2=12.94, PA1>B2>B1 (χ2=34.06, P0.05). Conclusion Compared with FBP, IMR technique can reduce image noise and improve image quality at low and high radiation doses, with better effect on low dose (80 kV, 500 mAs) hepatic CT.

Effect of Gadolinium Contrast Media on Intravoxel Incoherent Motion MRI of Abdominal Solid Organs / 中国医学影像学杂志

PurposeTo prospectively investigate the effect of gadolinium contrast media on the quality of intravoxel incoherent motion (IVIM) MRI images and the quantification of corresponding parameters for abdominal solid organs, and to explore the appropriate time for abdominal IVIM scan.Materials and MethodsTwenty patients underwent the same abdominal IVIM scan before and after gadolinium contrast administration. The signal-to-noise ratio (SNR) of liver, spleen, pancreas and kidneys were measured on diffusion-weighted imaging (DWI) images at b=50 s/mm2, 300 s/mm2 and 800 s/mm2. SNR and contrast-to-noise ratio (CNR) of hepatocellular carcinoma (HCC) (n=16) were also calculated. Apparent diffusion coefficient (ADC) value and IVIM parameters including pure diffusion coefficient (D), pseudo-diffusion coefficient (D*) and perfusion fraction (f) of liver, spleen, kidneys parenchyma and HCC were measured and compared. ResultsSNR of liver on post-contrast DWI at b=50 s/mm2 were significantly lower than that of pre-contrast (t=2.397,P0.05). As for IVIM parameters, only ADC and D values of kidneys demonstrated a significant reduction after contrast (ADC:t=3.569,P0.05). ConclusionAdministration of gadolinium contrast media may result in decrease of SNR of liver on low b value DWI and SNR of kidneys at any b value, but it increases CNR of hepatic lesions on medium b value DWI. Administration of gadolinium contrast media does not make a significant effect on SNR of spleen, pancreas and hepatic lesions. Furthermore, ADC and D values of kidneys decrease after administration of gadolinium contrast media. There is no significant influence of contrast medium on DWI and IVIM parameters of liver, hepatic lesions and spleen.

CT and MRI findings of desmoid-type fibromatoses / 实用放射学杂志

Objective To investigate the CT and MRI features of desmoid-type fibromatoses(DF).Methods The images of 29 ca-ses with DF proved by pathology were reviewed retrospectively.CT and MRI examinations were performed in 1 5 cases respectively, and both in 1 case.Results The median age was 33.0 years with a male-to-female sex ratio of 1 ︰ 2.2.36 lesions were discovered,among which 26 cases were solitary while 3 cases had multiple focus.1 9 lesions were extra-abdominal,14 ones in the abdominal wall and 3 ones intra-abdominal.The largest diameter of tumors was 13 -1 75 mm.27 lesions displayed ovoid or elongated shape while 9 ones were irregular .The boundary could be clear or unclear.25 lesions extended along muscle planes with consistent long axis.23 focuses grew aggressively,1 6 of which crossed the muscle clearance,while 13 lesions grew expansively.On CT,20 lesions appeared iso-den-sity or slightly hypo-density compared with normal muscles,mostly homogeneous(1 5/20).Most lesions exhibited gadually moderate or obvious enhancement on post-contrast CT,and the enhancement was homogeneous or heterogeneous.1 7 lesions were found on MRI,which presented signal intensity similar to or slightly higher than that of muscles on T1 WI and most were homogeneous(12/1 7);on T2 WI,all were heterogenous with slightly high or high intensity.All lesions demonstrated obvious enhancement on MRI after contrast administration ,and most were heterogeneous(12/1 7).Sheets or bands of low signal were detected within 1 1 lesions with no enhancement.Conclusion DF has some characteristics on CT and MRI,which are valuable for accurate pre-operative diagnosis,and for evaluation of the lesion extent and involvement of adjacent structures.

Multiple b value diffusion-weighted MRI based on intravoxel incoherent motion model applied to lymphoma-pilot study / 中华放射学杂志

Objective To evaluate treatment effect of nodal lymphoma by using multiple b value diffusion-weighted MRI based on intravoxel incoherent motion (IVIM) model. Methods From November 2012 to November 2013, 22 patients with pathology confirmed lymphoma in Guangdong General Hospital were chosen. Patients were examined on a 1.5 T MR scanner with plain MRI scan and multiple b value diffusion-weighted MRI scan before and after cycle two of chemotherapy. According to chemotherapy response which evaluated after cycle 2 of chemotherapy, lymphoma nodes were divided into four groups:complete response (CR), partial response (PR), stable disease (SD), progressive disease (PD). Kruskal-Wallis H test was used to compare prechemotherapy D value, f value among CR, PR, SD groups. Nemenyi test was used to compare prechemotherapy D value between the two of CR, PR, SD groups. One-way ANOVA was used to compare D*value among CR, PR, SD groups. Paired-sample t test was used to compare D, f, D*value between before and after chemotherapy in PR group. CR and PR group were ascribed to curative group, and SD group ascribed to poor response group. ROC curve was used to evaluate the predictive efficiency of parameters derived from IVIM. Results Twenty-two lymphoma patients were scanned before chemotherapy and 21 patients were scanned after cycle 2 of chemotherapy. There were 49 lesions in CR group, 17 lesions in PR group, 8 lesions in SD group and no lesions in PD group. Prechemotherapy D value of CR, PR, SD group were (0.63±0.26)×10-3, (0.57±0.10)×10-3,(0.42±0.04)×10-3 mm2/s, respectively. There was significant difference among the three groups (H=12.944,P=0.002). There was no statistically difference of prechemotherapy D value between CR and PR group (χ2=0.072,P=0.965). Prechemotherapy D value was lower in SD group than that in CR group (χ2=12.090,P=0.002) and PR group (χ2=10.684,P=0.005). There was no statistically difference of prechemotherapy f value among CR, PR, SD groups (χ2=2.312,P=0.315) or D*value (F=0.535,P=0.588). D value significantly increased after chemotherapy in PR group [(1.03±0.37)× 10-3 vs.(0.63 ± 0.26)× 10-3 mm2/s, t=-4.781, P=0.001]. f value significantly increased after chemotherapy in PR group [(9.39 ± 4.52)% vs.(6.44 ± 3.25)%, t=2.294, P=0.036]. D* value slightly increased after chemotherapy but with no statistical difference in PR group [(99.72 ± 42.12)× 10-3 vs.(90.37 ± 45.33)× 10-3 mm2/s, t=-0.579, P=0.570]. When a D value of 0.48 × 10-3 mm2/s was used as the threshold value for predicting chemotherapy response, the best results were obtained with sensitivity of 100.00%and specificity of 75.76%.Conclusions Prechemotherapy D value can predict chemotherapy response and D value can monitor chemotherapy response in lymphoma.

Application of iterative model reconstruction iterative reconstruction in cardiac CT imaging--an animal experimental study / 中华放射学杂志

Objective To evaluate the value of iterative modal reconstruction (IMR) for reducing radiation dose and controlling image quality in cardiac CT. Methods Ten pigs were included. All pigs were scanned on a 256?slice prospectively ECG?gated cardiac CT utilizing routine dose (group A) and tube current reduced by 30%(group B), 50%(group C) and 70%(group D), respectively. Filtered back projection (FBP), hybrid iterative reconstruction (iDose4) and IMR were used for all data, respectively. Image noise and contrast?to?noise ratio (CNR) of ascending aortic root were measured, while overall image quality and coronary artery image quality was rated (five point scale). All results reconstructed by FBP, iDose 4 and IMR were compared. Objective measurements were compared with one?way analysis of variance, and subjective assessments were compared with Kruskal?Wallis H test andχ2 test. Results Compared with that of FBP and iDose4, image noise of IMR was(15.1 ± 6.1),(18.8 ± 5.5),(22.1 ± 4.8)and(33.0 ± 4.0)HU, respectively in group A, B, C and D with significant reduction (F=82.77, 90.71, 96.59, 95.51 respectively, all P0.05) in the diagnosis rates of proximal coronary arteries compared with that using FBP and iDose4, while group C (100%, 40/40) and group D(92%, 37/40) had significantly increased diagnosis rates (χ2=20.05, 45.72, both P<0.01). The diagnosis rates of distal coronary arteries of IMR reconstruction which were 100%(50/50), 98%(49/50), 90%(45/50), 78%(39/50), respectively in groups A, B, C, D had significant increase compared with that of FBP and iDose4 reconstruction (χ2=7.39, 16.75, 34.62, 81.33, all P<0.05). Conclusions IMR can significantly reduce image noise, improve CNR and image quality compared with iDose4. Application of IMR can reduce radiation dose but without compromising image quality.