A preliminary study on prediction efficacy of multimodal MRI-based radiomics in combination with random forest model for preoperative glioma IDH1 gene type expression / 中华放射学杂志

Objective@#To preliminarily analyze the prediction efficiency of multimodal MRI-based radiomics model for preoperative glioma IDH1 gene expression type.@*Methods@#The MRI data of 108 surgery-proven glioma patients from May 2015 to January 2019 were retrospectively analyzed, and the MRI data included axial T1WI,T2WI,fluid attenuated inversion recovery (FLAIR),DWI imaging and enhanced T1WI sequence.Forty-seven cases were IDH1 mutant type, and 61 cases were IDH1 wild type. All patients were divided into training and validation groups according to the 7∶3 ratio of the random forest model. Seventy-three cases were in training group, and 35 cases were in validation group. Independent predictors of IDH1 mutation were screened by univariate analysis combined with multivariate logistic regression analysis (P<0.05) in order to construct a random forest diagnosis model of general clinical information and conventional MRI morphological features.General clinical information and conventional MRI morphological features included gender, age, umbers of cases of left and right hemispheres, location of tumors, maximum diameter of tumors, peritumoral edema, intratumoral cystic degeneration, enhancement and ADC value of tumors. The ROI was manually outlined by MaZda software in the most obvious level of 5 sequences of tumor mass and the radiomics features were extracted, including the gray-level co-occurrence matrix(GLCM), the run-length matrix(RUN), the absolute gradient(GRA),the auto-regressive model(ARM) and wavelets transform(WAV). The least absolute shrinkage and selection operator (LASSO)regression were used to select image radiomics features with a method of 10 fold cross -validation and to reduce the dimensions. The screened image radiomics labels were combined with the conventional morphological feature independent predictors to construct a multimodal MRI-based random forest model, and the validation data set was used to evaluate the accuracy and diagnostic efficiency of each model. The sensitivity and specificity of conventional MRI morphological feature model and multimodal MRI-based radiomics prediction model were evaluated dynamically by drawing ROC curves, and the prediction efficiency of the two models was quantified by using AUC statistical indicators. The model classification error rate under different outcomes and the classification error rate of out of bag(OOB)were used to evaluate the stability of the multimodal MRI-based random forest model. The contribution rate of each variable to the model was reflected by the characteristic variables importance assessment map.@*Results@#Univariate regression analysis of the conventional MRI morphological characteristics showed that peritumoral edema, cystic degeneration and enhancement were the three independent predictors of IDH1 gene expression (P<0.01). LASSO algorithm and 10-fold cross-validation identified six robust radiomic features including high frequency coefficients of wavelet transform (WavEnHH_s-4) of T2WI, S(4,4) inverse difference of gray uniformity measurement (InvDfMom),S(5,0) Entropy (entropy),WavEnHH_s-4 of T1WI enhancement, S(1,1) InvDfMom,S(1, -1) Entropy Difference (DifEntrp)of Flair.The error rate of classification for different outcomes and classification error rate of random forest OOB data of multimodal MRI radiomics diagnosis model finally stabilized at 10%. The results of Characteristic Variable Importance Assessment Map: Mean Decrease Accuracy and Mean Decrease Gini index were consistent, which showed that besides three conventional MRI morphological predictors peritumoral edema, enhancement and cystic degeneration, the radiomics labels also played a key role in the model. The results of ROC curve showed that the accuracy, specificity, sensitivity and AUC of conventional MRI morphological feature model were 82.7%, 68.4%, 90.9% and 0.835, respectively, and those of multimodal MRI-based radiomics model were 88.5%, 89.5%, 87.8% and 0.956 respectively.@*Conclusion@#Multimodal MRI-based radiomics random forest model can improve the predictive efficiency of preoperative glioma IDH1 gene expression type more quantitatively.

A preliminary study on prediction efficacy of multimodal MRI?based radiomics in combination with random forest model for preoperative glioma IDH1 gene type expression / 中华放射学杂志

Objective To preliminarily analyze the prediction efficiency of multimodal MRI?based radiomics model for preoperative glioma IDH1 gene expression type. Methods The MRI data of 108 surgery?proven glioma patients from May 2015 to January 2019 were retrospectively analyzed, and the MRI data included axial T1WI,T2WI,fluid attenuated inversion recovery (FLAIR),DWI imaging and enhanced T1WI sequence.Forty-seven cases were IDH1 mutant type, and 61 cases were IDH1 wild type. All patients were divided into training and validation groups according to the 7∶3 ratio of the random forest model. Seventy-three cases were in training group, and 35 cases were in validation group. Independent predictors of IDH1 mutation were screened by univariate analysis combined with multivariate logistic regression analysis (P<0.05) in order to construct a random forest diagnosis model of general clinical information and conventional MRI morphological features.General clinical information and conventional MRI morphological features included gender, age, umbers of cases of left and right hemispheres, location of tumors, maximum diameter of tumors, peritumoral edema, intratumoral cystic degeneration, enhancement and ADC value of tumors. The ROI was manually outlined by MaZda software in the most obvious level of 5 sequences of tumor mass and the radiomics features were extracted, including the gray?level co?occurrence matrix(GLCM), the run?length matrix(RUN), the absolute gradient(GRA),the auto?regressive model(ARM) and wavelets transform (WAV). The least absolute shrinkage and selection operator (LASSO)regression were used to select image radiomics features with a method of 10 fold cross?validation and to reduce the dimensions. The screened image radiomics labels were combined with the conventional morphological feature independent predictors to construct a multimodal MRI?based random forest model, and the validation data set was used to evaluate the accuracy and diagnostic efficiency of each model. The sensitivity and specificity of conventional MRI morphological feature model and multimodal MRI?based radiomics prediction model were evaluated dynamically by drawing ROC curves, and the prediction efficiency of the two models was quantified by using AUC statistical indicators. The model classification error rate under different outcomes and the classification error rate of out of bag(OOB)were used to evaluate the stability of the multimodal MRI?based random forest model. The contribution rate of each variable to the model was reflected by the characteristic variables importance assessment map. Results Univariate regression analysis of the conventional MRI morphological characteristics showed that peritumoral edema, cystic degeneration and enhancement were the three independent predictors of IDH1 gene expression (P<0.01). LASSO algorithm and 10?fold cross?validation identified six robust radiomic features including high frequency coefficients of wavelet transform (WavEnHH_s?4) of T2WI, S(4, 4) inverse difference of gray uniformity measurement (InvDfMom), S(5, 0) Entropy (entropy), WavEnHH_s?4 of T1WI enhancement, S(1, 1) InvDfMom, S(1, -1) Entropy Difference (DifEntrp)of Flair.The error rate of classification for different outcomes and classification error rate of random forest OOB data of multimodal MRI radiomics diagnosis model finally stabilized at 10%. The results of Characteristic Variable Importance Assessment Map: Mean Decrease Accuracy and Mean Decrease Gini index were consistent, which showed that besides three conventional MRI morphological predictors peritumoral edema, enhancement and cystic degeneration, the radiomics labels also played a key role in the model. The results of ROC curve showed that the accuracy, specificity,sensitivity and AUC of conventional MRI morphological feature model were 82.7%, 68.4%, 90.9% and 0.835, respectively, and those of multimodal MRI?based radiomics model were 88.5%, 89.5%, 87.8% and 0.956 respectively. Conclusion Multimodal MRI?based radiomics random forest model can improve the predictive efficiency of preoperative glioma IDH1 gene expression type more quantitatively.

Feasibility study of low concentration iso_osmolar contrast agent and low tube voltage for rabbit hepatic computed tomography perfusion scanning / 中华放射医学与防护杂志

Objective To investigate the feasibility of low-c oncentration iso_osmolar contrast agent together with low tube voltage and iterative reconstruction algorithm in rabbit liver computed tonography (CT) perfusion imaging.Methods A total of 15 bealthy New Zealand rabbits were scanned twice of liver CT perfusion scans each with 24 hours interval.The first scan (routine group) was acquired at 100 kV and 100 mAs with ultravist (370 mg/ml),while the second (double low group) was acquired at 80 kV and 100 mAs with iodixanol (270 mg/ml) at 24 hours after the first scan.The obtained images were reconstructed with filtered back projection (FBP) and adaptive iterative dose reduction (AIDR-3D)algorithms in the controlled and experimental groups,respectively.The perfusion parameters including hepatic artery perfusion(HAP),portal vein perfasion(PVP),hepatic perfusion index(HPI),and total liver perfusion(TLP) and image quality as image quality score,average CT value of abdomen aorta,signalto-noise ratio(SNR),carrier-to-noise ratio(CNR),and figure of merit(FOM) were compared used pair ttest or Mann-Whitney U-test between the two groups wherever appropriate.The effective radiation dose and iodine intake were also recorded and compared.Results The image quality and perfusion parameters had no significantly different between the two groups except for FOM.The effective radiation dose and iodine intake were 38.79％ and 27.03％ lower in the double low group.Conclusions Low concentration iso _osmolar contrast agent (iodixanol,270 mg/ml) together with low tube voltage (80 kV) helps to reduce radiation dose and iodine intake without compromising perfusion parameters and image quality in liver CT perfusion imaging.

Association of parameters in dynamic contrast-enhanced MRI using reference region model with prognostic factors and molecular subtypes of breast cancer / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the association of parameters in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) using reference region model with prognostic factors and molecular subtypes of breast cancer.</p><p><b>METHODS</b>MRI and pathological data of 50 patients with pathologically confirmed invasive ductal carcinoma of the breast were retrospectively analyzed. Reference region model was applied to analyze pharmacokinetic quantitative parameters including volume transfer constant (RR K), rate constant (K) and the ratio of Kto extracellular space volume (K/V). The associations of the above parameters with prognostic factors and molecular subtypes of breast cancer were analyzed.</p><p><b>RESULTS</b>RR Kand Kwere significantly higher in patients of histological grade 3 compared with those of histological grade 1 & 2 (all<0.05); and the patients with estrogen receptor (ER)-negative and/or progesterone receptor (PR)-negative also had higher RR Kand Kthan those with ER-positive or PR-positive (all<0.05). For immunohistochemistry, RR Kand Kwere significantly higher in triple negative breast cancer compared with luminal type breast cancer (all<0.05).</p><p><b>CONCLUSIONS</b>High RR Kand Kare associated with poor prognosis of breast cancer, and which can also be used to distinguish molecular subtypes of breast cancer.</p>

The value of MSCT in differentiating low-or high-risk thymomas and thymic carcinomas with maximum diameter equal or less than 3 cm / 实用放射学杂志

Objective To evaluate the diagnostic value of MSCT in the differentiation of thymic epithelial tumours (TET)with the maximum diameter equal or less than 3 cm.Methods A retrospective analysis of pathological and imaging data of 56 patients with pathologically confirmed TET with the maximum diameter equal or less than 3 cm was performed.According to the 2004 WHO classification,56 TETs were classified as low-risk thymomas(types A/AB/B1),high-risk thymomas (types B2/B3)and thymic carcinomas (type C).The CT manifestations of TET in each group,including shape of tumor,tumor edge (smooth or spiculate protuberance), presence of small nodule around tumor,enhancement degree,pleura invasion and fat space around tumor,were analyzed retrospectively.The differences in the CT manifestations among three types were compared using chi-square test.If the sample number was too small, Fisher 's exact test was used.Results Compared with high-risk thymomas (23 cases)and thymic carcinomas (6 cases),regular round shape was more often observed in low-risk thymomas (27 cases)(χ2 =73,P <0.001;χ2 =116,P <0.001)and the mediastinum-lung interface was more likely to bulge (χ2 = 3.41,P =0.046;χ2 =7.39,P =0.01).Blurred edge,spiculate protuberance and pleural invasion and so on were significantly more common in high-risk thymomas and thymic carcinomas (P <0.001)and they were the most common in thymic carcinomas (χ2 =11.5,P =0.009).There was a significant difference between type B2 thymomas and thymic carcinomas (χ2 =31.52, P <0.001),however there was no significant difference between type B3 thymomas and thymic carcinomas (χ2 =6.96,P =0.07). Conclusion MSCT can accurately show the shape of tumor,tumor edge,presence of small nodule around tumor,enhancement degree,pleura invasion,which can predict the histologic type of thymomas and also can provide information for preoperative diagnosis and prognosis evaluation.

The value of MSCT in differentiating low-or high-risk thymomas and thymic carcinomas with maximum diameter equal or less than 3 cm / 实用放射学杂志

Objective To evaluate the diagnostic value of MSCT in the differentiation of thymic epithelial tumours (TET)with the maximum diameter equal or less than 3 cm.Methods A retrospective analysis of pathological and imaging data of 56 patients with pathologically confirmed TET with the maximum diameter equal or less than 3 cm was performed.According to the 2004 WHO classification,56 TETs were classified as low-risk thymomas(types A/AB/B1),high-risk thymomas (types B2/B3)and thymic carcinomas (type C).The CT manifestations of TET in each group,including shape of tumor,tumor edge (smooth or spiculate protuberance), presence of small nodule around tumor,enhancement degree,pleura invasion and fat space around tumor,were analyzed retrospectively.The differences in the CT manifestations among three types were compared using chi-square test.If the sample number was too small, Fisher 's exact test was used.Results Compared with high-risk thymomas (23 cases)and thymic carcinomas (6 cases),regular round shape was more often observed in low-risk thymomas (27 cases)(χ2 =73,P <0.001;χ2 =116,P <0.001)and the mediastinum-lung interface was more likely to bulge (χ2 = 3.41,P =0.046;χ2 =7.39,P =0.01).Blurred edge,spiculate protuberance and pleural invasion and so on were significantly more common in high-risk thymomas and thymic carcinomas (P <0.001)and they were the most common in thymic carcinomas (χ2 =11.5,P =0.009).There was a significant difference between type B2 thymomas and thymic carcinomas (χ2 =31.52, P <0.001),however there was no significant difference between type B3 thymomas and thymic carcinomas (χ2 =6.96,P =0.07). Conclusion MSCT can accurately show the shape of tumor,tumor edge,presence of small nodule around tumor,enhancement degree,pleura invasion,which can predict the histologic type of thymomas and also can provide information for preoperative diagnosis and prognosis evaluation.

Application of low-tube-voltage combined with adaptive iterative reconstruction in lower extremity computed tomography angiography / 中华放射医学与防护杂志

Objective To investigate the feasibility of low-tube-voltage in combination with the three-dimensional adaptive iterative dose reduction (AIDR-3D) algorithm in performing lower extremity computed tomography angiography (CTA).Methods A total of 60 patients suspicious of lower extremity arterial occlusion were randomized into control group (120 kV,a =30) and experimental group (100 kV,n =30).The CTA was undertaken with a 320-row scanner (Toshiba Aquilion ONE),and the images was reconstructed with filtered back projection (FBP) algorithm in control group and FBP as well as the AIDR-3D algorithm in experimental group.The subjective image quality,vascular density (VD),noise,signal-to-noise ratio (SNR),contrast-to-noise ratio (CNR),and dose length product (DLP) were compared between two groups.Results The DLP was significantly lower in experimental group than that in control group [(503.5± 104.7) vs.(1 099.4 ± 151.7) mGy·cm,t =15.7,P ＜0.05].The images in experimental group with 100 kV and FBP protocol had significantly increased VD and noise (t =-3.13,-3.61,P ＜ 0.05) than that in the control.The images in experimental group with AIDR-3D had significantly lower noise and higher SNR and CNR than that with FBP (t =13.59,2.14,P ＜ 0.05),also significantly lower noise and significantly higher VD,SNR,and CNR than that in the control (t =-3.75,-4.19,-4.15,P ＜ 0.05).Conclusions Low-tube-voltage (100 kV) combined with AIDR-3D reconstruction could significantly improve the image quality and reduce radiation dose in lower extremity CTA with a 320-row CT scanner.Trial registration Chinese clinical trial registry,ChiCTR-DPD-16008054.

Coronary computed tomographic angiography at low concentration of contrast media and low tube voltage in obese patients / 中华放射医学与防护杂志

Objective To explore the feasibility of coronary computed tomographic angiography (CCTA) for obese patients with lower tube voltage (100 kV) and lower contrast media concentration (270 mgI/ml) using iterative reconstruction.Methods A total of 48 patients with body mass index greater than 30 kg/m2 were included and randomly divided into 2 groups according to random number table method.The images of the control group were obtained using iodine 370 mgI/ml, a tube voltage of 120 kV, and traditional filtered back projection (FBP) image reconstruction.Patients in the test group were injected with isotonic low concentration contrast media (270 mgI/ml), scanned with a lower tube voltage (100 kV), and adaptive iterative noise reduction image reconstruction algorithm (AIDR-3D) was used.Two experienced physicians scored the image quality in a double-blind way.Independent sample t-test was used to compare the effective dose (E), average CT values, signal to noise ratio (SNR), contrast to noise ratio (CNR), the figure of merit (FOM), image quality scores and the total iodine intake.Side effect was also evaluated.Results The subjective scores for control group and test group were not significantly different (P ＞ 0.05).The scores of two physicians were consistency (Kappa =0.88, P ＜ 0.05).The average CT values, SNR and CNR for the two groups were not significantly different (P ＞ 0.05), but the FOM of the test group was significantly higher than that of the control group (t =-9.250,-8.604,-9.158,-5.341, P ＜ 0.05).Effective dose in the test group was (1.61 ± 0.41) mSv, lower than that of the control group (t =8.373, P ＜ 0.01).The total iodine and iodine injection rate in the test group were both lower than in the control group (t =7.628, 8.480, P ＜ 0.01).The incidence of contrast mediarelated discomfort in the test group was lower than control group (x2 =18.70, 6.25, P ＜ 0.05).Conclusions For obese patients, isotonic low concentration of contrast media and low-dose CCTA could be feasible, which substantially reduce the radiation dose and iodine intake without sacrificing image quality.Trial registration Chinese clinical trial registry, ChiCTR-DPD-15007510.

Application value of low radiation dose coronary angiography using 320-slice volume CT / 中华放射医学与防护杂志

Objective To evaluate the image quality and radiation dose of prospective electrocardiography-triggered coronary 320-slice volume CT angiography with different kV, and the feasibility of coronary scan with ＜ 1 mSv radiation dose.Methods Eighty consecutive patients were randomly divided into two groups equally.The tube voltage according to paradigm was 100 kV in group A and 120 kV in group B.All raw data in group A was reconstructed by the software AIDR in CT system to create a new group named as A1. Such parameters as the mean intraluminal attenuation (SI),noise (SD),signal-to-noise ratio (SNR),contrast-to-noise ratio (CNR),effective radiation dose(E) and image quality score measured in group A were compared with those in group B.The values such as SI,SD,SNR,CNR,image quality scores were compared between group A and group A1.The significance of group B and group A1 was compared in SI,SD,SNR,CNR,image quality scores as well.Results E in group A was significantly lower than that in group B[ E =(0.67 ± 0.18) mSv in group A vs.E =(3.08 ± 1.04) mSv in group B].The value of E in group A was decreased by 78％ compared to group B(t =- 14.30,P＜0.05 ).There was no significant difference in mean image quality scores between two groups(4.57 ± 0.57in groupA vs.4.59 ± 0.59 in group B,t=-1.17,P＞0.05).The values of SI,SD,SNR,CNR in group A were (570.8 ±131.5)HU,25.1 ±6.9,24.5 ±9.1,19.8 ±6.1.And the values of SI,SD,SNR,CNR in group B were (460.6 ± 14.3) HU,15.1 ±3.6,31.7 ±7.7,29.3 ±6.8.The values of SI and SD in group A were significantly higher than those in group B(t =4.49,8.18,P ＜0.05). The values of SNR and CNR in group A were lower than those in group B (t =-4.24,-6.19,P＜0.05).The valuesofS1,SD,SNR,CNR,image quality scores in group Al were (557.9 ±24.5) HU,21.1 ±6.0,27.7±10.0,23.4±7.8,4.60 ± 0.56.There was no difference in the SI and the image quality scores between group A and group A1 ( t =1.09,- 1.90,P ＞ 0.05).Conclusions 320-slice volume CT with 100 kV tube voltage and prospective ECG-triggered technique can reduce the radiation dose to less than 1 mSv and obtain optimal images in diagnosis of coronary arterial diseases.

Evaluation of upper airway resilience under Müller respiration by non-endoscopic method / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To evaluate diagnostic significance of the noninvasive and objective 320-slice CT scan in the high pharynx resilience in the patients with obstructive sleep apnea/hypopnea syndrome.@*METHOD@#Fifty patients with OSAHS and 10 patients with pharyngeal paraesthesia were included in the study. 320 slice CT scan was used to measure the sagittal diameters, transverse diameters and sectional area of the retropalatal region, retroglossal region. Calculating the pharynx wall resilience. Analyzing the correlativity of pharynx wall resilience, BMI and AHI. Fiber endoscope was used to assess the subsidence percentage of the pharynx wall.@*RESULT@#Between OSAHS patients and pharyngeal paraesthesia patients, there was obviously difference in the retropalatal region and retroglossal region upper airway. The pharynx wall resiliences of retropalatal region were much more than that of retroglossal region. The later pharynx wall resiliences were much more than the fore-to-aft pharynx wall resiliences in the retropalatal region. BMI, AHI and the pharynx wall resilience were positive correlative to each other. But AHI and the pharynx wall resilience was nonlinear correlative. There was a good concordance between the pharynx wall resilience detected by 320CT and subsidence percentage of the pharynx wall detected by fiber endoscope.@*CONCLUSION@#320 slice CT is a kind of simple, rapid and objective method to localize the high resilience area of upper respiratory tract, which can be benefit to the clinical diagnosis, the etiological study and the treatment of OSAHS. Based on physical examination, we propose that only one time of CT scan to the patients' upper airway at the Muller' stage is enough to localize the stenosis area, which can reduce radiation dosage dramatically.

Molecular Characterization of Avian-like H1N1 Swine Influenza A Viruses Isolated in Eastern China, 2011 / 中国病毒学·英文版

Currently,three predominant subtypes of influenza virus are prevalent in pig populations worldwide:H1N1,H3N2,and H1N2.European avian-like H1N1 viruses,which were initially detected in European pig populations in 1979,have been circulating in pigs in eastern China since 2007.In this study,six influenza A viruses were isolated from 60 swine lung samples collected from January to April 2011 in eastern China.Based on whole genome sequencing,molecular characteristics of two isolates were determined.Phylogenetic analysis showed the eight genes of the two isolates were closely related to those of the avian-like H1N1 viruses circulating in pig populations,especially similar to those found in China.Four potential glycosylation sites were observed at positions 13,26,198,277 in the HA1 proteins of the two isolates.Due to the presence of a stop codon at codon 12,the isolates contained truncated PB1-F2 proteins.In this study,the isolates contained 591Q,627E and 701N in the polymerase subunit PB2,which had been shown to be determinants of virulence and host adaptation.The isolates also had a D rather than E at position 92 of the NS1,a marker of mammalian adaptation.Both isolates contained the GPKV motif at the PDZ ligand domain of the 3' end of the NS1,a characteristic marker of the European avian-like swine viruses since about 1999,which is distinct from those of avian,human and classical swine viruses.The M2 proteins of the isolates have the mutation (S31N),a characteristic marker of the European avian-like swine viruses since about 1987,which may confer resistance to amantadine and rimantadine antivirals.Our findings further emphasize the importance of surveillance on the genetic diversity of influenza A viruses in pigs,and raise more concerns about the occurrence of cross-species transmission events.