A multimodal medical image contrastive learning algorithm with domain adaptive denormalization / 生物医学工程学杂志

Recently, deep learning has achieved impressive results in medical image tasks. However, this method usually requires large-scale annotated data, and medical images are expensive to annotate, so it is a challenge to learn efficiently from the limited annotated data. Currently, the two commonly used methods are transfer learning and self-supervised learning. However, these two methods have been little studied in multimodal medical images, so this study proposes a contrastive learning method for multimodal medical images. The method takes images of different modalities of the same patient as positive samples, which effectively increases the number of positive samples in the training process and helps the model to fully learn the similarities and differences of lesions on images of different modalities, thus improving the model's understanding of medical images and diagnostic accuracy. The commonly used data augmentation methods are not suitable for multimodal images, so this paper proposes a domain adaptive denormalization method to transform the source domain images with the help of statistical information of the target domain. In this study, the method is validated with two different multimodal medical image classification tasks: in the microvascular infiltration recognition task, the method achieves an accuracy of (74.79 ± 0.74)% and an F1 score of (78.37 ± 1.94)%, which are improved as compared with other conventional learning methods; for the brain tumor pathology grading task, the method also achieves significant improvements. The results show that the method achieves good results on multimodal medical images and can provide a reference solution for pre-training multimodal medical images.

Hepatocellular carcinoma segmentation and pathological differentiation degree prediction method based on multi-task learning / 生物医学工程学杂志

Hepatocellular carcinoma (HCC) is the most common liver malignancy, where HCC segmentation and prediction of the degree of pathological differentiation are two important tasks in surgical treatment and prognosis evaluation. Existing methods usually solve these two problems independently without considering the correlation of the two tasks. In this paper, we propose a multi-task learning model that aims to accomplish the segmentation task and classification task simultaneously. The model consists of a segmentation subnet and a classification subnet. A multi-scale feature fusion method is proposed in the classification subnet to improve the classification accuracy, and a boundary-aware attention is designed in the segmentation subnet to solve the problem of tumor over-segmentation. A dynamic weighted average multi-task loss is used to make the model achieve optimal performance in both tasks simultaneously. The experimental results of this method on 295 HCC patients are superior to other multi-task learning methods, with a Dice similarity coefficient (Dice) of (83.9 ± 0.88)% on the segmentation task, while the average recall is (86.08 ± 0.83)% and an F1 score is (80.05 ± 1.7)% on the classification task. The results show that the multi-task learning method proposed in this paper can perform the classification task and segmentation task well at the same time, which can provide theoretical reference for clinical diagnosis and treatment of HCC patients.

Application of echo-planar imaging correction in diffusion weighted imaging and diffusion tensor imaging of cervical spinal cord / 中华放射学杂志

Objective:To explore the value of echo-planar imaging correction (EPIC) for improving image quality of diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI) of cervical cord.Methods:A total of 33 subjects (20 males, 13 females) were scanned on a 3.0 T MR scanner from January to March 2022, and the sequences included T 1WI, DWI and DTI (with and without corrections). Two observers delineated the regions of interest (ROIs) on the fused images of DWI and DTI with T 1WI before and after correction, and measured the average diffusion coefficient (ADC), fractional anisotropy (FA), and offset distance of ROIs between images with and without corrections. The subjective scores of image quality were also evaluated. The ICC or Kappa was used to test the consistency of the quantitative measurement and subjective scores by the two observers. The average values by the two observers would be used for subsequent analysis. The independent pair t-test and Wilcoxon test were used for comparison of objective measurements and Mann-Whitney U test was used for subjective image assessments between images with and without corrections. Results:The measurement data and the subjective scores of the two observers were in good agreement (ICC 0.912-0.999, Kappa 0.778-0.816). The independent sample t-test showed the subjective scores were significantly different for the DWI and DTI images between before and after geometry and/or ADC corrections. The ADC values of C6, the offset distances measured by DWI before and after correction of C4, C5, and C6 and subjective scores were significantly different ( P<0.05); The FA values of C1 and C3, ADC values of C1 and C3, offset distance of C4, C5 and C6 measured by DTI before and after correction and subjective scores were statistically significant ( P<0.001). Conclusion:EPI geometry correction and ADC value correction can significantly reduce geometric distortion, increase image quality, and thus improve the diagnosis accuracy of essential diseases.

Consistency study of FRACTURE sequence and CT in evaluating bone changes of knee and ankle / 中华放射学杂志

Objective:To explore the consistency of MRI fast field echo resembling a CT using restricted echo-spacing (FRACTURE) and CT in the evaluation of knee and ankle bone changes.Methods:From November 2020 to November 2021, seventeen patients who underwent CT and MRI FRACTURE examinations of knee joint or ankle joint in the First Affiliated Hospital of Dalian Medical University were retrospectively collected, including 14 patients with knee joint examinations and 3 patients with ankle joint examinations. According to the number of joint components, 80 components were included, including 14 for femur and patella, 17 for tibia and fibula, and 3 for talus, scaphoid, medial cuneiform, medial cuneiform, lateral cuneiform and calcaneus, respectively. The fracture, hyperosteogeny, and bone destruction of the joint bones were evaluated by two observers using CT and FRACTURE images, respectively. Kappa test was used to analyze the consistency of CT and FRACTURE images between observers in the evaluation of joint bone lesions.Results:The Kappa values (95%CI) of the consistency evaluation of fracture, hyperosteogeny, and bone destruction by CT and FRACTURE images were 0.925 (0.823-1.027), 0.905 (0.799-1.011) and 0.895(0.752-1.038) respectively for observer 1, and were 0.963 (0.892-1.034), 0.933 (0.843-1.023) and 0.886 (0.731-1.041) respectively for observer 2. The Kappa values (95%CI) of the consistency evaluation of fracture, hyperosteogeny, and bone destruction by observers 1 and 2 via CT images were 1.000 (1.000-1.000), 0.937(0.851-1.023) and 0.945 (0.839-1.051) respectively, and that by FRACTURE images were 0.962 (0.888-1.036), 0.966 (0.899-1.033) and 0.836 (0.656-1.016) respectively.Conclusion:For the evaluation of fracture, hyperosteogeny, and bone destruction of knee joint and ankle joint, MRI FRACTURE sequence is highly consistent with CT.

Acid-base metabolism variants in infarct core and penumbra using amide proton transfer weighted imaging in subacute cerebral infarction / 中华放射学杂志

Objective:To assess the value of amide proton transfer weighted (APTw) imaging in the evaluation of pH changes in infarct core (IC) and ischemic penumbra (IP) in subacute cerebral infarction.Methods:The data of twenty-three subacute cerebral infarction patients with unilateral steno-occlusive disease of the middle cerebral artery (subacute infarction group) from April to November 2019 in the First Affiliated Hospital of Dalian Medical University were prospectively analyzed. Fifteen healthy volunteers were enrolled in this study as the control group. All subjects underwent conventional MRI, DWI, 3D-pseudo continuous arterial spin labeling (3D-pCASL) and APTw sequences. Based on DWI images, relative cerebral blood flow (rCBF) and APTw images to determine the region of IC, blood flow penumbra [cerebral blood flow(CBF)-DWI mismatch area, IP CBF] and metabolic penumbra (APTw-DWI mismatched area, IP APT). 3D ROIs were used to semi-automatically measure the APTw signals and the volume of IC and IP CBF of the patients in subacute infarction group. The comparison of APTw signals between the infarct side and the contralateral side in the subacute infarction group, the comparison of bilateral APTw signals in the control group, and the comparison of APTw signals in the IC and IP CBF regions were performed by paired-sample t test or Wilcoxon signed-rank test. The paired-sample t test or Mann-Whitney U test was used to compare the APTw signals between the two groups. The Friedman test was applied to compare the difference of volumes among IP CBF1.5, IP CBF2.5 and IP APT . Results:There was no significant difference of the APTw signals among the IC, the contralateral side in the subacute infarction group and the control group ( P>0.05). The APTw signals of IP CBF and IC of the infarction group were statistically different ( P<0.05). Compared with the contralateral side of IP CBF1.5 (3.7±1.7, -1.84±1.48, 5.57±2.75), the APTwmax (3.07±1.41, t=-3.012, P=0.006), APTw min [-1.30 (-1.74, -0.57), Z=-2.099, P=0.036], and APTwmax-min(4.51±2.58, t=-3.273, P=0.003) signals in the IP CBF1.5 were decreased ( P<0.05). Compared with the contralateral side of IP CBF2.5 [-1.53 (-2.80, -0.91), 5.31±2.61], the APTw min [-1.08 (-1.60, -0.49), Z=-2.616, P=0.009] and APTwmax-min (4.41±2.72, t=-3.228, P=0.004) signals in the IP CBF2.5 were decreased. The volumes of IP CBF1.5 [107.51(50.08, 138.61)mm 3], IP APT [99.00 (53.27, 121.335) mm 3] and IP CBF2.5 [89.91 (51.53, 139.87) mm 3] were successively reduced (χ2=7.913, P=0.019), and the volume of IP CBF2.5 was significantly smaller than that of IP CBF1.5 ( P=0.037). Conclusion:The acid-base metabolism in the IC of subacute cerebral infarction is not obvious, but the blood flow penumbra has local acid-base metabolism imbalance, and the range of metabolic penumbra coincides with the blood flow penumbra.

FeasibilitystudyofMRIDEAL-IQsequenceinevaluatingliverfunctionofpatientswithlivercirrhosis / 实用放射学杂志

Objective ToinvestigatethefeasibilityofassessingliverfunctiongradingbyIDEAL-IQsequenceon1.5T MR.Methods The patientswhowereclinicallydiagnosedaslivecirrhosisandunderwent1.5T MRIDEAL-IQsequenceinourhospitalfrom February 2016toDecember2017wereanalyzedretrospectively.TheyweredividedintoA,BandCgradesaccordingtotheChild-Pughgrading standardofliverfunction.Finally,therewere30patientsinChild-PughA,25patientsinChild-PughBand16patientsinChild-Pugh C.ThefatratiomapsandR2?relaxationratemapswereusedtomeasuretheliverfatcontentandironcontentbythetwoobservers onAW4.6workstation,respectively.ThemeanvaluesofthefatfractionsandtheR2?valuesweremeasuredandcomparedbyusing K ruskal-W allis H testamongthethreegroups.Then,thegroupAandBwerecombinedtoestablishthepredictivemodelindiagnosingthegroup Cbyusingthe L o g istic regressionanalysis,whichcombinedthefatfractionandR2?value.TheROCcurvewasdrawntoobtainedtheAUC,and calculatedthesensitivityandthespecificitywiththeoptimalthreshold.Results Thereweregoodconsistencyofmeasurementdata betweenthetwoobserves(ICC>0.8).ThefatfractionandR2?valueincreasedwiththedecreaseoftheliverfunction.Thefatfractionsofthe Child-PughA,BandCgroupwere(3.58±0.91)%,(3.64±1.20)%,(6.87±3.91)%,respectively.TheR2?valuesoftheChild-Pugh A,BandCgroupswere(33.31±11.80)Hz,(38.00±13.31)Hz,(58.98±44.54)Hz,respectively.TheAUCofwhichcombinedfat fractionandR2?valuediagnosingChild-PughCwas0.843.Thesensitivityandthespecificitywere81.8% and81.3%,respectively. Conclusion The1.5T MRIDEAL-IQsequencecanbeusedtoevaluatetheliverreserveunctionoflivercirrhosispatientsaccording ffatfractionandR2?value,especiallyfortheChild-PughCcirrhosis patientswithhighsensitivityandspecificity.

Application of a deep machine learning technique for low dose renal CT perfusion / 中华放射医学与防护杂志

Objective To assess the ability of a deep machine learning technique for improving the quality of one-stop renal low dose CTP images.Methods Twenty-one cases who underwent renal noncontrast CT,triple-phase contrast enhanced CT,and CT perfusion (CTP) were collected prospectively.Revolution CT scanner was used with the scan protocol as followed:120 kVp,20 mA for CTP and 100 mA for triple-phase conctrast enhancement,axial scan,ASIR-V80％,rotation 0.5 s,coverage area for z-axial 160 mm,thickness 5 mm.A total of 15 phases were obtained for the first 28 s and then scanned once at 39,43,47,51,63,83,113,213,353,593 s for CTP,which the phases at the 22,51 and 153 s were the cortical phase,medullary phase and excretory phase,respectively.All CTP data was reconstructed with a deep machine learning technique pixel shine A7 model.The data before and after reconstruction was in group A and in group B,respectively.Compared the all data of cortex in the cortical phase and CTP parameters between the two groups.Results There were significant differences of CT values of SD of cortex (9.04 ± 1.77 and 5.75 ± 1.00,respectively),CT values of SD of elector spinae (8.52 ±2.28 and 5.67 ±0.98,respectively),CNR(16.28 ±6.61 and 28.90 ±1.50,respectively) and SNR (21.41 ± 6.67 and 30.65 ± 7.67,respectively) between the two groups (t=1.562,6.286,5.925,-5.892,-17.274,P＜0.05).The SD of images after PS-B was lower than that before PS-B significantly and SNR was improved obviously.There were no differences of cortical blood flow (BF),blood volume (BV),time to peak (TP) and medullary permeability of surface (PS) between the two groups (P ＞ 0.05).Conclusions The reconstruction of deep machine learning PixelShine technique PS-A7 can reduce the noise of images obtained with low tube current,improve the SNR and can not effect the CTP parameters.

Influence on image quality in low-dose colonography with adaptive statistical iterative reconstruction algorithm / 中华放射医学与防护杂志

Objective To evaluate the feasibility of adaptive statistical iterative reconstruction-V (ASIR-V) to improve image quality in low-dose CT colonography.Methods A series of thirty artificial polyps were established by ligation in an isolated segment of porcine colon.Volume data was acquired on Revolution CT scanner (GE,USA) with High Definition scan mode and different scan parameter combinations:120 kVp with different mAs (10,30,50,70,90,100,120,140,160,180,200,220,240,260,respectively).Images were reconstructed with six different ASIR-V levels of 0 (filtered back projection,FBP),10％,30％,50％,70％ and 90％.Two radiologists were blinded to measure and analyze the objective data independently,including image noise (SD),signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR).The kappa test was used to assess interobserver agreement in subjective image quality score.ICC test was used to examine the consistency of the measurements between two observers.SD,SNR,CNR were performed for statistical analysis in different tube current and different levels of ASIR-V using variance analysis (ANOVA).Results Interobserver agreement for subjective image quality score was good with a kappa value of 0.683.The variation of the tube current(r =0.734,P =0.000) and ASIR-V level(r =0.220,P =0.044) is related to the subjective score of image quality.Under the condition of the same tube current,image quality score of 50％ ASIR-V reconstruction was the highest.Two objective data consistency is good.The differences of image noise (F =423.58,P ＜ 0.05),SNRs(F =124.26,P ＜ 0.05) and CNRs (F =1 030.17,P ＜ 0.05) of different tube current and different levels of ASIR-V reconstruction were statistically significant.In the same tube current,with increased levels of ASIR-V,image noise reduced,CNRs increased.Only in 10,120,140,160,220,240,260 mA,the differences of SNRs were statistically significant(F =8.75-31.36,P ＜ 0.05).For the same level of ASIR-V reconstruction,with the increase of tube current,the image noise decreased,SNR and CNR increased gradually.Conclusions In the CT colonography,the application of ASIR-V algorithm can significantly reduce the noise and enhance the image contrast noise ratio and improve image quality.ASIR-V algorithm with 50％ has better performance in reducing CT image noise.

PixelShine Algorithm in Enhancing the Quality of Reconstructed Abdominal Arterial Phase CT Image / 中国医学影像学杂志

Purpose To explore the feasibility of denoising algorithm-PixelShine algorithm based on deep learning to enhance the quality of abdominal arterial phase CT images rebuilt by 70 kVp combined with adaptive statistical iterative reconstruction-Veo (ASiR-V). Materials and Methods Abdominal arterial phase images of 33 patients [body mass index (BMI) BMI≤20 kg/m2] scanned by GE Revolution CT were retrospectively analyzed (group A) using 70 kVp tube voltage and 50% ASiR-V technique. PixelShine algorithm B2 mode was applied to post-process group A images to obtain PixelShine image (group B). Two observers rated the image quality of the two groups via a 5-point rating system. The consistency of the rating was analyzed. The difference in ratings, noise, virtual signal-to-noise ratio (SNR) of liver and pancreas and contrast noise ratio (CNR) were compared between the two groups of images. Results The image quality rating of group A and B were(3.12±0.33) scores and(3.97±0.53) scores respectively,noise value(14.50±1.42)HU vs(10.05±1.80)HU, liver virtual SNR 4.51±0.53 vs 6.78.±1.27,liver virtual CNR 0.89±0.55 vs 1.42±0.81,pancreatic virtual SNR 9.51±1.69 vs 13.87±3.26, and pancreatic virtual CNR 5.83±1.66 vs 8.48±2.46.The quality rating of images,liver and pancreas virtual SNR,CNR in group B were all higher than those in group A, and the image noise of group B decreased about 31% compared with that of group A, the difference was statistically significant (P<0.05). Conclusion Post-processing with PixelShine algorithm can improve the image quality of 70 kVp abdominal arterial phase, significantly reduce image noise, and increase image SNR and CNR.

Impact of pixel shine algorithm based on deep machine learning on image quality of abdominal low-dose plain CT scanning in patients with high body mass index / 中国医学影像技术

Objective To investigate the impact of deep machine learning Pixel Shine (PS) algorithm on image quality of abdominal low-dose plain CT scanning in BMI≥25 kg/m2 patients.Methods A total of 59 patients (BMI≥25 kg/m2) who underwent abdominal CT scan were collected.The patients were divided into group A (100 kVp,n=30) and B (120 kVp,n=29) according to the tube voltage.According to different reconstruction algorithms and treatment methods,patients in group A were divided into A1 (FBP),A2 (FBP+PS),A3 (50％ASiR-V) and A4 (50％ASiR-V+PS) subgroups,while in group B were divided into B1 (FBP) and B2 (50％ASiR-V) subgroups.CT and SD values of right hepatic lobe and right erector spinae were measured,then SNR and CNR of liver and CT dose index of volume (CTDIvol) were calculated.The consistency of parameters measured by two observers was evaluated.Results The consistency of parameters measured by two observers was good (all ICC＞0.80).There was no statistical difference of CT values of liver and erector among A1-A4 subgroups (all P＞0.05),whereas statistical differences of SD values of liver and erector spinae,also of SNR and CNR of liver were found (all P＜0.001).Among A1-A4 subgroups,SDA4 ＜SDA2 ＜SDA3 ＜SDA1,SNRA4 ＞SNRA2 ＞SNRA3 ＞ SNRA1 (all P＜0.001) was observed.There was no significant difference of CNR between A1 and A3 subgroup (P=0.078),while CNRA4＞ CNRA2＞ CNRA3 or CNRA1 (P＜0.001) was noticed.SD values of the liver in subgroup A2 was lower than subgroup B1,and A4 was lower than B2 subgroup (all P＜0.001),and SNR and CNR increased significantly in A2 and A4 subgroups (all P＜0.001).CTDIvol of group A was lower than that of group B (P＜0.001).Conclusion Deep machine learning PS algorithm can improve image quality of abdominal low-dose plain CT scanning in high-BMI patients.

Establishment of a rat model of lumbar spinal root avulsion / 中国实验动物学报

Objective To establish a rat model of spinal root avulsion and to validate the model by brain-derived neurotrophic factor(BDNF)treatment. Methods To evaluate the motor neuron loss,5 male SD rats were used to undergo spinal root avulsion surgery. One week later, the number of motor neurons in the ventral horn of the spinal cord was as-sessed by histopathology using immunohistochemical staining with a choline acetyl transferase(ChAT)antibody. After this pilot study,40 male SD rats at 7 weeks of age were randomly divided into 4 groups:two control groups,BDNF preventive and treatment groups. Results All rats recovered well post-surgery and no obvious abnormality was observed. Compared with the contralateral side,the number of motor neurons in the ipsilateral avulsed side was significantly decreased at one week after surgery(20.06%,P<0.05). Compared with the control group,there was a significant increase in ChAT posi-tive neurons in the BDNF preventive group(17.85% vs. 93.06%,P<0.0001)or BDNF treatment group(1week after surgery)(26.94% vs. 86.87%, P<0.0001), indicating that the motor neurons were effectively protected by BDNF. Conclusions A rat model of spinal root avulsion is successfully established,which can be valuable for studies of amyotro-phic lateral sclerosis and drug discovery efforts.

Assessing the Blood Supply Status of the Focal Ground-Glass Opacity in Lungs Using Spectral Computed Tomography

OBJECTIVE: To exploit material decomposition analysis in dual-energy spectral computed tomography (CT) to assess the blood supply status of the ground-glass opacity (GGO) in lungs. MATERIALS AND METHODS: This retrospective study included 48 patients with lung adenocarcinoma, who underwent a contrast-enhanced dual-energy spectral CT scan before treatment (53 GGOs in total). The iodine concentration (IC) and water content (WC) of the GGO, the contralateral and ipsilateral normal lung tissues were measured in the arterial phase (AP) and their differences were analyzed. IC, normalized IC (NIC), and WC values were compared between the pure ground-glass opacity (pGGO) and the mixed ground-glass opacity (mGGO), and between the group of preinvasive lesions and the minimally invasive adenocarcinoma (MIA) and invasive adenocarcinoma (IA) groups. RESULTS: The values of pGGO (IC = 20.9 ± 6.2 mg/mL and WC = 345.1 ± 87.1 mg/mL) and mGGO (IC = 23.8 ± 8.3 mg/mL and WC = 606.8 ± 124.5 mg/mL) in the AP were significantly higher than those of the contralateral normal lung tissues (IC = 15.0 ± 4.9 mg/mL and WC = 156.4 ± 36.8 mg/mL; IC = 16.2 ± 5.7 mg/mL and WC = 169.4 ± 41.0 mg/mL) and ipsilateral normal lung tissues (IC = 15.1 ± 6.2 mg/mL and WC = 156.3 ± 38.8 mg/mL; IC = 15.9 ± 6.0 mg/mL and WC = 174.7 ± 39.2 mg/mL; all p < 0.001). After normalizing the data according to the values of the artery, pGGO (NIC = 0.1 and WC = 345.1 ± 87.1 mg/mL) and mGGO (NIC = 0.2 and WC = 606.8 ± 124.5 mg/mL) were statistically different (p = 0.049 and p < 0.001, respectively), but not for the IC value (p = 0.161). The WC values of the group with preinvasive lesions and MIA (345.4 ± 96.1 mg/mL) and IA (550.1 ± 158.2 mg/mL) were statistically different (p < 0.001). CONCLUSION: Using dual-energy spectral CT and material decomposition analysis, the IC in GGO can be quantitatively measured which can be an indicator of the blood supply status in the GGO.

Quantitative evaluation of myocardium deformation in patients with hypertrophic cardiomyopathy by cardiovascular magnetic resonance feature tracking / 中国医学影像技术

Objective To explore the value of cardiovascular magnetic resonance feature tracking (CMR-FT) in quantita tive evaluation of myocardium deformation in patients with hypertrophic cardiomyopathy (HCM).Methods Sixteen HCM patients (HCM group) and 18 healthy volunteers (control group) were enrolled and measured with CMR-FT.The differences of left ventricular (LV) end diastolic volume (LVEDV),LV end systolic volume (LVESV),LV ejection fraction (LVEF),left ventricular mass (LVMASS) and LV global radial strain (RS),LV global circumferential strain (CS) were compared between the two groups.The correlations between segmental wall thickness and segmental RS and CS were studied.And the correlation among global RS,CS and LVEDV,LVESV,LVEF,LVMASS were analyzed.Results LVMASS in HCM group was higher than that in control group ([133.74±79.13]g vs [76.87±14.15]g,P=0.01).No sig nificant differences of LVEDV,LVESV,LVEF were found between HCM group and control group (all P＞0.05).Global RS and CS were significantly lower in HCM group than those in control group (RS:[27.05 ± 13.35]％ vs [40.62 ± 4.92] ％,P＜0.01;CS:[-8.68± 5.56] ％ vs [-20.73 ± 1.56] ％,P＜0.01).No significant correlations was observed between segmental wall thickness and segmental RS (r=-0.41,P＜0.01),CS (r=0.28,P＜0.01),respectively.In HCM group,no significant correlations was observed between global RS (r=-0.36,-0.41,0.22,-0.36),CS (r=0.34,0.10,0.22,0.42) and LVEDV,LVESV,LVEF,LVMASS,respectively (all P＞0.05).Conclusion CMR-FT is conducive to quantitative evaluate myocardial deformation in HCM patients.

Influence of arterial data on Revolution CT perfusion parameters of renal cell carcinoma / 中国医学影像技术

Objective To explore the effect of whole renal perfusion imaging removal of arterial phase data on perfusion parameters of renal clear cell carcinoma using Revolution CT.Methods Perfusion imaging with Revolution CT was retrospectively analyzed in 10 patients with pathologically proven clear cell renal cell carcinoma.The z-direction coverage model was used in perfusion imaging,and the images were analyzed with CT Perfusion 4D software.All images were analyzed twice.All 23 phases data was included in group A and only 16 phases except arterial data (9-15 phases) were selected in group B.The abdominal aorta on the level of right hilus was chosen to be the input artery,and the perfusion parameter maps were obtained,including blood flow (BF),blood volume (BV),mean transit time (MTT),permeability of surface (PS).Every perfusion parameters of lesions and contralateral normal cortex,lesions and normal cortex in both groups were compared.Results The BF and PS of lesions were lower than those of normal cortex in both groups (both P＜0.05).There was no statistical difference in BV and MTT between lesions and normal cortex in both groups (all P＞0.05).There was no statistical difference in all perfusion parameters of renal clear cell carcinoma between group A and group B (all P＞0.05).The difference of BF in normal cortex between the two groups was statistically significant (P 0.009),and the difference of the PS,BV,MTT had no statistically significant (all P＞0.05).Conclusion When the duration time of renal CTP is 600 s,there is no difference between including and excluding arterial phase in all perfusion parameters of renal clear cell carcinoma.

Feasibility of low radiation dose and iodine contrast medium in 70 kVp abdominal CTA in low body mass index patients / 中国医学影像技术

Objective To explore the feasibility of reducing radiation dose and iodine contrast medium in 70 kVp abdominal CTA imaging in low-body mass index (BMI;≤22 kg/m2) patients.Methods The 48 patients with suspected abdominal vascular diseases and low BMI (≤22 kg/m2) underwent abdominal CTA.All patients were divided into two groups according to tube voltage and contrast intake randomly.The parameters of group A (n=27) were contrast intake 300 mgI/kg,70 kVp,the conditions of group B (n=21) were contrast intake 500 mgI/kg,120 kVp,and the other conditions were the same in both groups.The image quality of right renal arterial images was evaluated by two observers simultaneously (5-scale).The consistency and difference between the two observers were analyzed.The CT values of abdominal aorta,celiac trunk,superior mesenteric artery,common hepatic artery,pancreatic artery and erector spinae,SD values of erector spinae on the level of right renal hilus were measured respectively in both groups.The CT values of abdominal aorta and its main branches,the CNR of abdominal aorta,the volume CT dose index (CTDIvol),dose-length product (DLP) and overall iodine intake in each group were compared.Results The scoring of right renal arterial images in both groups were 5.00 (1.00),the results showed a good consistency (Kappa=0.932,0.911).The CT values of abdominal aorta,superior mesenteric artery,common hepatic artery and pancreatic artery in group A were all more than those of in group B (all P＜0.05).The CNR of group A was higher than that of group B (P＜0.05).The CTDIvoland DLP in group A decreased by 73.36％ and 74.41％ compared with group B.The overall iodine intakes in group A and group B were (46.33±6.43)ml and (84.31±10.71)rnl,respectively.The overall iodine intake of group A decreased by 45.05％ compared with group B.Conclusion For patients with low BMI (≤22 kg/m2),a 70 kVp tube current abdominal CTA scanning can significantly increase the contrast of images of abdominal artery and its branches.Meanwhile,the radiation dose and overall iodine intake can obviously decrease.

Feasibility of whole-liver one-stop examination with Revolution CT / 中国医学影像技术

Objective To explore the feasibility of axial whole-liver one-stop examination with Revolution CT.Methods Totally 19 patients were underwent upper-abdominal enhanced examination with Revolution CT and acquired whole-liver CT perfusion (CTP),vein phase and balanced phase enhanced images.Two observers recorded the rank and peak CT value corresponding to time-density curve (TDC) of abdominal aorta and portal vein respectively on the CTP images.The perfusion parameters including blood flow (BF),blood volume (BV),hepatic arterial fraction (HAF),mean transit time (MTT),time to peak (TP) of left and right liver lobe were measured.The images of hepatic artery CTA and portal vein CTV were reconstructed and the arterial phase enhanced images were extracted using the images corresponding to abdominal aorta and portal vein peak TDC.And the radiation dose of CT perfusion and one-stop examination were recorded.The differences between perfusion parameters of left and right liver lobe were compared and the consistency of two observers were analyzed.Results The differences between BV and MTT of left and right liver lobe were statistical significance (both P＜0.05).The subjective scores of hepatic artery CTA,portal vein CTV and arterial phase images were greater than 1 point.The two observers were in great consistence (Kappa＞0.6).The effective radiation dose in perfusion phase and one-stop examination were 14.47 mSv and 21.29 mSv.Conclusion With low radiation dose,Revolution CT axial wholeliver perfusion one-stop examination can provide multiple quantitative parameters of liver CTP and clear hepatic artery CTA,portal vein CTV and 3 phase enhanced scan images,which has broadly prospective in clinical application.

CT and MRI manifestations of Kimura disease in head and neck / 中国医学影像技术

Objective To explore the CT and MRI manifestations of Kimura disease in head and neck.Methods The CT and MR findings of 20 cases with Kimura disease confirmed by pathology were collected.The lesion location,boundary,size,number,density of CT and signal intensity of MRI were analyzed.Results In 20 cases,multiple lesions were seen in 19 cases.There were 11 cases involving parotid gland,6 cases involving the submandibular area,2 cases in cheek,1 case in palate,2 cases involving the upper arm,1 case involving axillary fossa,1 case involving cervical lymph node alone,and 8 cases with subcutaneous nodules in the front or back of the ear,16 cases accompanied by lymphadenopathy in the neck (8 cases with lymphadenopathy in the parotid gland).The largest diameter of lesion was (3.09± 1.08)cm.The margin was blurred in 19 cases and well defined in 1 case.The isodensity lesions were found in 16 cases and slightly lower density lesions were in 4 cases in non-contrast enhanced CT scan.Calcification was not found in all cases.Homogeneous enhancement was found in 16 cases and inhomogeneous enhancement was found in 1 case.The enhancement degree varies from mild to strong enhancement.Homogenous signal and strong enhancement was found in 2 cases with MR scan.Conclusion The typical manifestations of Kimura disease are involvement of parotid gland and subcutaneous fat,accompanied by lymphadenopathy in the neck,homogeneous density on CT or MRI,which may indicate Kimura disease.

Feasibility of one-stop examination with wide detector CT for axial perfusion of pancreas / 中国医学影像技术

Objective To explore the feasibility of one-stop examination with Revolution CT for axial perfusion of normal pancreas.Methods Thirteen patients who received axial perfusion scan by one-stop examination with Revolution CT were analyzed as perfusion group.Two radiologists measured pancreatic CT perfusion (CTP) parameters independently and selected optimal phase for CTA and three phases of enhanced images.The effect dose (ED) was calculated.Eighteen patients who underwent abdominal enhanced CT and CTA with spiral scan were included as control group.Patients in both groups had no pancreatic disorders.The interobserver variation of CTP parameters was estimated.Two independent radiologists separated the superior pancreaticoduodenal artery (SPDA) image into 5 points according to image quality,and the consistency was assessed.The subjective points of SPDA image quality of two groups was compared.CT value,images noise,CNR and SNR of SPDA on CTA images and those of pancreas on three phases enhanced scan images between two groups were compared.Results ICC values of all CTP parameters were higher than 0.75.The ED of perfusion protocol was (24.52±-0.01)mSv.The subjective image scores of SPDA on CTA images in both groups were both 5,the consistency was good (Kappa=0.629,0.769).The CT value,CNR,and SNR of SPDA on CTA images of CTP group were higher than those of control group (all P＜0.05).The CT value,CNR,and SNR of pancreas of CTP group were higher than those of control group in venous phase and balanced phase (all P＜0.05).Conclusion The pancreatic CT one-stop examination can be performed by Revolution CT scanner with maximum detector width with acceptable radiation dose,from which pancreatic CT perfusion data,enhanced images with high quality and better CTA images can be extracted.

Diffusion tensor imaging in differential diagnosis of intrahepatic cholangiocarcinoma and hepatocellular carcinoma / 中国医学影像技术

Objective To explore the value of diffusion tensor imaging (DTI) in differential diagnosis of intrahepatic cholangiocarcinoma (ICC) and hepatocellular carcinoma (HCC).Methods Fifty-two patients including 20 patients with ICC (ICC group) and 32 patients with HCC (HCC group) confirmed by histopathological examination were recruited in the study.All the patients were performed MR exams on a 1.5T scanner in a protocol containing the routine T1WI,T2WI,DWI and DTI.The values of ADC,fractional anisotropy (FA),diffusion coefficient (D) were blindly reviewed and analyzed by two experienced observers,and were compared between two groups.The ROC curve was used to evaluate the di agnostic efficiency.Results The border clear percentage of ICC group (9/20,45.00％) had no significant difference compared with that of HCC group (15/32,46.88％;x2 =0.02,P=0.90),the detection rate of bile duct expansion in ICC group (11/20,55.00％) was higher than that in HCC group (4/32,12.50％;x2=10.83,P=0.001).Theintraclasscor relation coefficient value of ADC,D and FA in the ICC group and HCC group were all more than 0.90.The mean FA of ICCgroup (0.45±0.16) were significantly higher than that of HCC group (0.30±0.13;P=0.001),while the mean ADC and D values in ICC and HCC groups had no significant difference (both P＞0.05).The area under the ROC curve of FA was 0.76.And when FA=0.31,there was a higher sensitivity (85.0％) in identifying ICC and HCC.Conclusion The FA of DTI shows a stronger capability than the ADC and D values in differentiating the ICC from HCC.

MRI characteristics of solid papillary carcinomas in situ of breast / 中国介入影像与治疗学

Objective To evaluate MRI characteristics of solid papillary carcinomas (SPCs) in situ of the breast.Methods A retrospective study included 5 patients with pathologically confirmed SPC in situ was performed.MRI data before operation including conventional MRI,dynamic contrast enhanced MRI (DCE-MRI) and DWI were analyzed.Results All the lesions showed iso/hypointensity on T1 FSPGR sequence,iso/hyperintensity on FSE T2WI sequence and STIR sequence.Mass enhancements were observed for all lesions with oval or irregular shapes on DCE-MRI.The margin of lesions were circumscribed,and internal enhancements were homogeneous or heterogeneous.Time intensity curve appeared a rapid increase in initial contrast phases and platform or outflow types in delayed phases.All the lesions on DWI showed slightly hyperintensity with the ADC value range from 1.34 × 10-3 mm2/s to 1.96)× 10-3 mm2/s.Conclusion MRI manifestations of SPC are characteristics,which may provide valuable information to distinguish SPC in situ from other invasive breast carcinomas.