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Objective:To investigate the value of intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) parameters combined with T 2WI texture analysis of primary lesions of rectal adenocarcinoma in preoperative prediction of lymph node metastasis with short diameter ≤9 mm. Methods:Retrospective analysis was performed on 115 cases of rectal adenocarcinoma confirmed by surgical pathology in Affiliated Provincial Hospital of Anhui Medical University from June 2015 to October 2020. All patients underwent total mesorectal resection and received conventional rectal MRI and IVIM-DWI scan before surgery. According to the pathological results of lymph node, the patients were divided into lymph node metastatic group ( n=44) and non-metastatic group ( n=71). IVIM-DWI parameters of primary rectal adenocarcinoma were measured including apparent diffusion coefficient (ADC), diffusion coefficient (D), pseudo diffusion coefficient (D *) and perfusion fraction (f). The region of interest (ROI) of the whole lesion of rectal adenocarcinoma was delineated on axial T 2WI; then the ROIs were imported into GE Analysis Kit software to extract 3D texture feature. The differences of IVIM-DWI parameters and texture feature parameters were compared between two groups using independent sample t test or Mann-Whitney U test. The optimal texture feature parameters with independent predictive function were screened by multivariate logistic regression. Then the texture feature model and combined model based IVIM-DWI and texture feature parameters were established. The receiver operating characteristic (ROC) curves were used to evaluate the performances of IVIM-DWI, texture feature parameters, texture feature model and combined model in predicting lymph node metastasis in patients with rectal adenocarcinoma. The area under the ROC curve (AUC) were compared with DeLong test. Results:Among all the IVIM-DWI parameters, the D * and f values of primary rectal adenocarcinoma were significantly different between the lymph node metastasis group and the non-lymph node metastasis group ( Z=3.39, P=0.001, Z=-3.06, P=0.002); no statistical significance was found in the ADC and D values between two groups (both P>0.05). A total of 828 texture feature parameters were obtained based on T 2WI of primary lesion of rectal adenocarcinoma, among which 3 optimal texture feature parameters were selected, including firstorder_Skewness, shape_Sphericity and glcm_Idn. The ROC curve results showed that the AUC of D * and f were 0.689 and 0.670, respectively. The AUC of 3 texture feature parameters were 0.651, 0.628, 0.631, respectively. The AUC of texture feature model and the combined model were 0.775 and 0.803. The AUC of combined model was larger than D *, f and the three texture feature parameters (all P<0.05). Conclusion:IVIM-DWI parameters combined with T 2WI texture feature parameters in primary lesion of rectal adenocarcinoma show good diagnostic efficacy in preoperative prediction of lymph node metastasis with short diameter≤9 mm.
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Objective To explore the classic MRI appearance of secondary hemochromatosis (SHC)related liver iron overload, and the feasibility of quantitative evaluation of liver iron overload by iterative decomposition of water and fat with echo asymmetry and leastGsquares estimationGiron quantification (IDEALGIQ).Methods 20 patients with SHCGrelated liver iron overload (experimental group)and 20 healthy adults (control group)underwent routine liver MRI and IDEALGIQ.The MRI images were comparatively analyzed to assess the hallmark of liver iron overload.In both two groups,the R2 ? values were measured on R2 ? maps,which were generated by IDEALGIQ,then the differences in age,gender and R2 ? value between two groups were comparatively analyzed.In experimental group,the serum ferritin (SF)was detected,and a correlation analysis was tested with R2 ? value.Results For all of the 20 patients, there was signal drop of liver parenchyma on T1 and T2 Gweighted images,signal loss with susceptibility artifact on DWI images,and signal dropped on inGphase images relative to outGofGphase images.Among the 20 patients,18 cases appeared "a dark liver parenchyma"on T2 G weighted images,and the spleen signal in 3 cases was similar to liver parenchyma’s hallmark.The R2 ? values in experimental group and control group were 395.58±255.75 Hz and 41.18±7.86 Hz (t＝－6.12,P＝0.00),respectively.No significant differences between two groups were found in gender and age (χ2＝0.10,P＝0.10 and t＝0.09,P＝0.93).The liver iron overload R2? value was not correlated with SF (r＝0.1 5 3 , P＝0.15).Conclusion On MRI,the typical appearance of liver iron overload is hypointense on T1 and T2Gweighted images,especially"a dark liver parenchyma"on T2 WI,signal drops on inGphase images relative to outGofGphase images,and signal loss with susceptibility artifact on DWI images.R2 ? value of IDEALGIQ can quantitatively evaluate the liver iron overload,without a correlation with SF.
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Objective To investigate CT enhanced effect in abdominal vessels with three different iodine concentration with the fixed iodine delivery rate and total iodine load.Methods 90 patients were randomized into 270 (270 mg I/mL),320 (320 mg I/mL) and 370 (370 mg I/mL)groups.On arterial phase images,the CT values of abdominal aorta (AA)were measured at the level of the porta hepatis,the right renal artery and the bifurcation of iliac artery.On portal veins phase images,the CT values of the main portal vein,the left branch and the right branch of portal vein were also measured.The differences in subj ective scores of image quality,CT values,signal to noise ratio (SNR),contrast to noise ratio (CNR)between the AA and portal vein were analyzed.Results The CT values of AA in 270,320 and 370 groups in arterial phase at the level of the porta hepatis were(302.28±24.81)HU,(302.14±33.76)HU and (303.49±35.85)HU,those at the right renal artery level were(304.01±25.55)HU,(305.22±33.63)HU and(306.14±31.51)HU,and at the bifurcation of iliac artery level were (306.85±23.26)HU,(308.68±31.80)HU and (310.22±29.76)HU.There were no significant differences among the three groups (P>0.05).The CT values of the main portal vein in portal phase were (133.94±8.41)HU, (1 3 5.6 3 ± 11.82)HU and(135.43±10.08)HU,those of the left branch were(134.21±6.04)HU,(135.12±9.97)HU and(135.31±8.82)HU, those of the right branch were (133.77±7.06)HU,(134.09±11.53)HU and (136.04±10.61)HU.There were also no significant differences among the three groups (P>0.05).No statistical differences were observed among the three groups in the scores of image quality, SNR and CNR(P>0.0 5).Conclusion Similar CT enhanced effect and excellent image quality can be obtained by using different iodine concentration of contrast agent with the fixed iodine delivery rate and total iodine load in abdominal vessels.
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Objective To explore the value of spectral CT imaging in the preoperative evaluation on histodifferentiation of rectal adenocarcinoma.Methods 90 patients with rectal adenocarcinoma underwent dual-phase enhanced spectral CT scan,and were divided into well,moderately and poorly differentiated adenocarcinoma groups according to the pathology.Single-energy images with energy levels from 40 to 140 keV were generated by GSI Viewer software,and the slope K value of the energy curves were calculated.Iodine concentrations were derived from iodine-based material-separation images and normalized to the iodine concentrations in the aorta. ROC curves were derived to evaluate the differentiation diagnosis efficiency of normalized iodine concentration (NIC)and slope K in rectal adenocarcinoma,respectively.Results There were 22,50 and 18 cases in the well,moderately and poorly differentiated group,respectively.The iodine concentration,NIC and slope K value were statistically different both in the arterial and venous phase (P76% and the specificity>74% in the arterial phase,and the sensitivity>77% and the specificity>70% in the venous phase by choo-sing the appropriate threshold.Conclusion The spectral CT can provide a new method for preoperatively evaluating the histodiffer-entiation of rectal adenocarcinoma.
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Objective To explore the correlation between apparent diffusion coefficient (ADC) and pathological grading and staging of cervical carcinoma.Methods Among 311 patients diagnosed with squamous cell carcinoma,87 patients were met the criteria for inclusion.All the patients were performed routine MR and diffusion-weighted imaging(DWI) with b=1 000 s/mm2 before treatments,and recorded the pathological grading and staging.The ADC values of the lesions were measured on GE AW4.5 workstation,and were compared among the groups with different pathological grading and staging by using LSD and paired t-test.Results The mean ADC value was (0.77±0.079)×10-3 mm2/s in the poorly-differentiated group,(0.88±0.10)×10-3 mm2/s in the moderately-differentiated group,and (1.05±0.084)×10-3 mm2/s in the well-differentiated group.There were significant differences among the different groups (P0.05).Conclusion The increasing of the ADC values is correlated with the high levels of tumor cell differentiation, and not correlated with the pathological stages in cervical carcinoma.
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Objective To evaluate the value of low concentration of isotonic contrast agent combined with 80 kV and adaptive statistical itera-tive reconstruction (ASiR)technique for bronchial artery with CT angiography (CTA).Methods 40 patients (18.5 kg/m2 ≤ body mass index(BMI)≤25 kg/m2 )with lung cancer were randomly divided into two groups and performed enhanced chest CT examina-tion.20 patients (low concentration group)were scanned with Visipaque 270mg I/mL,scanning protocol of (80 kV,260 mA)and other 20 patients (high concentration group)were scanned with Ultravist 370 mg I/mL,scanning protocol of (120 kV,1 50 mA). The CT value,signal noise (SD),signal-to-noise ratio (SNR),contrast-to-noise ratio (CNR)and effective dose (ED)of the two groups were compared and analyzed statistically.Differences between the two groups were determined with t test(P <0.05).Results The mean CT value of the low concentration group (31 7.33 HU±70.44 HU)was higher than that of the high concentration group (256.39 HU±37.38 HU)(P <0.05).SD,ED and dose length product (DLP)of the low concentration group (SD:7.55 ±1.51 HU;ED:1.74±0.14 mSv;DLP:124.94±9.9 mGy/cm)were lower than those of the high concentration group (SD:9.36±1.26 HU;ED:3.20±0.35 mSv;DLP:228.82±25.13 mGy/cm)(P <0.05).CNR and SNR of the low concentration group (CNR:59.71± 17.36;SNR:44.01±14.71)were higher than those of the high concentration group (CNR:37.61±6.16;SNR:27.75±4.72)(P <0.05).The subjective scores of the two groups were (3.73±0.66)and (3.81±0.59),respectively,with no statistical difference.Conclusion For the patients with normal body mass index ,it can reduce 47% radiation dose and 27% iodine dosage using low concentration of isotonic contrast agent combined with 80kV and ASiR technique for bronchial artery CTA,while maintaining similar excellent image quality.
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Objective To investigate the optimal monochromatic parameters of CT angiography (CTA) on small feeding arteries of abdominal tumors using single source dual-energy CT with gemstone spectral imaging (GSI) technique.Methods The clinical and medical imaging data of 32 patients with abdominal malignant tumor were analyzed retrospectively during January to April 2012.Three phase-enhanced CT scans (Discovery CT750 HD,GE Heahhcare,Milwaukee,USA) of the abdomen were recorded using the GSI technique on 32 patients.The minor feeding arteries of tumor with diameter between 1.5 mm to 3.0 mm were reconstructed by 140 kVp mixed energy,66 keV,and optimal monochromatic mode respectively.After CT scanning,the original data were processed with layer and interval of 0.625 mm,the 140 kVp mixed energy images and 70 keV monochromatic images were obtained with standard algorithm.The original images were conveyed to AW4.5 work-station to process furthermore,then the data of the optimal monochromatic group and 66 keV group were reconstructed.Comparative parameters include contrast-to-noise ratio (CNR),signal-to-noise ratio (SNR) and subjective scores of the small feeding arteries CTA quality.Subjective scores were evaluated by two radiologists according to the sharpness and resolution of the small feeding arteries.One-way ANOVA was used to for statistical analysis.Results CNR of the optimal monochromatic group,the 66 keY group,and the 140 kVp mixed energy group were 21.70 ±9.74,16.63 ±7.60,and 9.85± 6.76,respectively.SNR were 35.05 ± 17.75,26.77 ± 11.51,and 16.32 ± 9.5,respectively.Subjective scores were 4.58 ± 0.40,3.55 ± 0.57,and 2.75 ± 0.46,respectively.CNR,SNR and subjective scores had significant difference among groups (F =17.11,15.73 and 116.01,P ＜ 0.01).The optimal monochromatic group was superior to the 66 keV group and the 140 kVp mixed energy group.Conclusion The optimal monochromatic mode can improve CTA quality of small feeding arteries of abdomen malignant tumors with GSI technique using single source dual-energy CT.