Value for combination of T1WI star -VIBE with TWIST -VIBE dynamic contrast -enhanced MRI in distinguishing lung nodules / 中南大学学报(医学版)

OBJECTIVES@#With the increasing detection rate of lung nodules, the qualitative problem of lung nodules has become one of the key clinical issues. This study aims to evaluate the value of combining dynamic contrast-enhanced (DCE) MRI based on time-resolved imaging with interleaved stochastic trajectories-volume interpolated breath hold examination (TWIST-VIBE) with T1 weighted free-breathing star-volumetric interpolated breath hold examination (T1WI star-VIBE) in identifying benign and malignant lung nodules.@*METHODS@#We retrospectively analyzed 79 adults with undetermined lung nodules before the operation. All nodules of patients included were classified into malignant nodules (n=58) and benign nodules (n=26) based on final diagnosis. The unenhanced T1WI-VIBE, the contrast-enhanced T1WI star-VIBE, and the DCE curve based on TWIST-VIBE were performed. The corresponding qualitative [wash-in time, wash-out time, time to peak (TTP), arrival time (AT), positive enhancement integral (PEI)] and quantitative parameters [volume transfer constant (Ktrans), interstitium-to-plasma rate constant (Kep), and fractional extracellular space volume (Ve)] were evaluated. Besides, the diagnostic efficacy (sensitivity and specificity) of enhanced CT and MRI were compared.@*RESULTS@#There were significant differences in unenhanced T1WI-VIBE hypo-intensity, and type of A, B, C DCE curve type between benign and malignant lung nodules (all P<0.001). Pulmonary malignant nodules had a shorter wash-out time than benign nodules (P=0.001), and the differences of the remaining parameters were not statistically significant (all P>0.05). After T1WI star-VIBE contrast-enhanced MRI, the image quality was further improved. Compared with enhanced CT scan, the sensitivity (82.76% vs 80.50%) and the specificity (69.23% vs 57.10%) based on MRI were higher than that of CT (both P<0.001).@*CONCLUSIONS@#T1WI star-VIBE and dynamic contrast-enhanced MRI based on TWIST-VIBE were helpful to improve the image resolution and provide more information for clinical differentiation between benign and malignant lung nodules.

Clinical imaging analysis of 12 cases of orbital solitary fibrous tumor / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM:To investigate the characteristics of color Doppler sonography and MRI in orbital solitary fibrous tumor(SFT). <p>METHODS: It was a retrospective case series study. A total of 12 cases of orbital solitary fibrous tumors were recruited from April 2013 to August 2018 in Tianjin Medical University Eye Hospital. Color Doppler sonography and MRI plain scan and DCE-MRI were applied in all cases. <p>RESULTS: Of 12 cases, 7 cases were males and 5 were females, with the duration of symptoms ranged from 3mo-20y, with an average course of 3.2y; 6 cases were the primary cases and 6 cases were relapse cases. All lesions involved one side of the orbit, of which 8 cases were in the left orbit and 4 in the right. Of 12 cases, there were 5 tumors in intraconal space, 3 in the extraconal space, and 4 in intra and extraconal space. Well-circumscribed lesions showed oval shape in 9 cases and the left 3 were irregular. 12 cases showed hypoechoic and 2 cases heterogeneous signal on color Doppler sonography; All cases had flow signals on CDFI, and showed arterial spectrum on PW. On T1WI, all lesions demonstrated isointense. On T2WI, 5 lesions showed hypointense, 3 lesions showed isointense and 4 lesions slight hyperintense, of which 3 lesions showed heterogeneous signal. After contrast enhancement, all cases demonstrated markedly enhancement, with homogeneous enhancement in 10 cases and heterogeneous enhancement in 2 cases. The time-intensity curves(TIC)of 7 cases exhibited a rapid washout pattern, and 5 cases a rapid plateau pattern on DCE-MRI. <p>CONCLUSION: Color Doppler sonography features of orbital SFT include hypoechoic and flow signals. Heterogeneous signals on T2WI, marked enhancement, and a rapidly enhancing and slow washout pattern TIC on DCE-MRI are the typical MRI features of orbital SFT.

Advanced Methods in Dynamic Contrast Enhanced Arterial Phase Imaging of the Liver

Dynamic contrast enhanced (DCE) magnetic resonance (MR) imaging plays an important role in non-invasive detection and characterization of primary and metastatic lesions in the liver. Recently, efforts have been made to improve spatial and temporal resolution of DCE liver MRI for arterial phase imaging. Review of recent publications related to arterial phase imaging of the liver indicates that there exist primarily two approaches: breath-hold and free-breathing. For breath-hold imaging, acquiring multiple arterial phase images in a breath-hold is the preferred approach over conventional single-phase imaging. For free-breathing imaging, a combination of three-dimensional (3D) stack-of-stars golden-angle sampling and compressed sensing parallel imaging reconstruction is one of emerging techniques. Self-gating can be used to decrease respiratory motion artifact. This article introduces recent MRI technologies relevant to hepatic arterial phase imaging, including differential subsampling with Cartesian ordering (DISCO), golden-angle radial sparse parallel (GRASP), and X-D GRASP. This article also describes techniques related to dynamic 3D image reconstruction of the liver from golden-angle stack-of-stars data.

Clinical study on dynamic contrast-enhanced MRI in tumor bed of breast cancer with different region of interest selections / 中国癌症杂志

Background and purpose: The technique of dynamic contrast-enhanced MRI (DCE-MRI) is widely applied in differential diagnosis between benign and malignant tumor and therapeutic estimation of neoadjuvant chemotherapy in clinic. However, there is no standard quantitative measurement method. This study aimed to assess the variability of different region of interest (ROI) selections for tumor bed of breast cancer using DCE-MRI, and to ascertain the optimal ROI delineation. Methods: We retrospectively analyzed DCE-MRI of 30 patients diagnosed with breast cancer by pathology. The ROIs were delineated by 2 different observers using iCAD software with 4 methods, including whole tumor (Whole), the slice containing the most enhancing voxels (SliceMax), 3 slices centered in SliceMax (Partial) and the 5％ most enhancing contiguous voxels within SliceMax (5Max), to generate the volume transfer constant (Ktrans), the extracellular volume fraction (Ve) and rate constant (Kep). And the reproducibilities of the measurements were assessed using the Bland-Altman method. Results: In the analysis of ROIs delineation, the Ktrans, Ve and Kep reported by different observers were 1.26±0.54 vs 1.25±0.53, 0.75±0.23 vs 0.73±0.22 and 1.93±1.46 vs 1.95±1.51 (P＞0.05) using the method of Whole, and 1.28±0.43 vs 1.26±0.43, 0.74±0.21 vs 0.80±0.27, 1.95±1.53 vs 1.93±1.43 (P＞0.05) using the method of Partial, and 1.30±0.33 vs 1.32±0.33, 0.77±0.20 vs 0.73±0.24, 1.82±1.53 vs 1.87±1.45 (P＞0.05) using the method of SliceMax, and 1.31±0.35 vs 1.35±0.33, 0.77±0.20 vs 0.98±0.25, 1.97±1.36 vs 1.73±1.55 using the method of 5Max (P＜0.05). Using the methods of ROI delineation except 5Max, there was no significant difference between Ktrans, Ve and Kep reported by different observers. The bias vs limits of agreement were 0.002 vs-0.013 to 0.012,-0.003 vs-0.023 to 0.017, 0.006 vs-0.018 to 0.029,-0.035 vs-0.054 to 0.018 measured with Whole method, SliceMax, Partial and 5Max respectively using the Bland-Altman method. Conclusion: It may be reliable to measure functional parameters of primary tumors in breast cancer using DCE-MRI according to the methods of Whole, Partial and SliceMax.

Application of Synthetic MRI for Direct Measurement of Magnetic Resonance Relaxation Time and Tumor Volume at Multiple Time Points after Contrast Administration: Preliminary Results in Patients with Brain Metastasis

OBJECTIVE: The purpose of this study was to investigate the time-dependent effects of contrast medium on multi-dynamic, multi-echo (MDME) sequence in patients with brain metastases. MATERIALS AND METHODS: This study included 7 patients with 15 brain metastases who underwent magnetic resonance (MR) examination which included MDME sequences at 1 minute, 10 minutes and 20 minutes after contrast injection. Two volumes of interests, covering an entire tumor (whole tumor) and the enhancing portion of the tumor, were derived from post-contrast synthetic T1-weighted images. Statistical comparisons were performed for three different time delays for histogram parameters of the longitudinal relaxation rate (R1) and the transverse relaxation rate (R2), and lesion volumes. RESULTS: The mean and the median of R1 and the mean of R2 in both the whole tumor and the inner enhancing portion were larger on the 10 minutes delayed images than on the 1 minute or 20 minutes delayed images (mean of R1 in the whole tumor on the 1 minute, 10 minutes, and 20 minutes delayed images: 1.26 ms, 1.39 ms, and 1.37 ms; mean of R1 in the inner enhancing portion: 1.43 ms, 1.53 ms and 1.44 ms; all p < 0.017). The volumes of the whole tumor and the inner enhancing portion were significantly larger in the 10 minutes and 20 minutes delayed images than on the 1 minute delayed images (all p < 0.017). CONCLUSION: Magnetic resonance relaxation times and the volumes of the whole tumor and the inner enhancing portion were measured larger on the 10 minutes or 20 minutes delayed images than on the 1 minute delayed images. The MDME sequence immediately after contrast injection cannot fully reflect the effects of gadolinium-based contrast agent leakage in the tissue.

Assessment of Blood-Brain Barrier Permeability by Dynamic Contrast-Enhanced MRI in Transient Middle Cerebral Artery Occlusion Model after Localized Brain Cooling in Rats

OBJECTIVE: The purpose of this study was to evaluate the effects of localized brain cooling on blood-brain barrier (BBB) permeability following transient middle cerebral artery occlusion (tMCAO) in rats, by using dynamic contrast-enhanced (DCE)-MRI. MATERIALS AND METHODS: Thirty rats were divided into 3 groups of 10 rats each: control group, localized cold-saline (20℃) infusion group, and localized warm-saline (37℃) infusion group. The left middle cerebral artery (MCA) was occluded for 1 hour in anesthetized rats, followed by 3 hours of reperfusion. In the localized saline infusion group, 6 mL of cold or warm saline was infused through the hollow filament for 10 minutes after MCA occlusion. DCE-MRI investigations were performed after 3 hours and 24 hours of reperfusion. Pharmacokinetic parameters of the extended Tofts-Kety model were calculated for each DCE-MRI. In addition, rotarod testing was performed before tMCAO, and on days 1-9 after tMCAO. Myeloperoxidase (MPO) immunohisto-chemistry was performed to identify infiltrating neutrophils associated with the inflammatory response in the rat brain. RESULTS: Permeability parameters showed no statistical significance between cold and warm saline infusion groups after 3-hour reperfusion 0.09 ± 0.01 min-1 vs. 0.07 ± 0.02 min-1, p = 0.661 for K(trans); 0.30 ± 0.05 min-1 vs. 0.37 ± 0.11 min-1, p = 0.394 for kep, respectively. Behavioral testing revealed no significant difference among the three groups. However, the percentage of MPO-positive cells in the cold-saline group was significantly lower than those in the control and warm-saline groups (p < 0.05). CONCLUSION: Localized brain cooling (20℃) does not confer a benefit to inhibit the increase in BBB permeability that follows transient cerebral ischemia and reperfusion in an animal model, as compared with localized warm-saline (37℃) infusion group.

Intravoxel Incoherent Motion MR Imaging in the Head and Neck: Correlation with Dynamic Contrast-Enhanced MR Imaging and Diffusion-Weighted Imaging

OBJECTIVE: To investigate the correlation between perfusion- and diffusion-related parameters from intravoxel incoherent motion (IVIM) and those from dynamic contrast-enhanced MR imaging (DCE-MRI) and diffusion-weighted imaging in tumors and normal muscles of the head and neck. MATERIALS AND METHODS: We retrospectively enrolled 20 consecutive patients with head and neck tumors with MR imaging performed using a 3T MR scanner. Tissue diffusivity (D), pseudo-diffusion coefficient (D*), and perfusion fraction (f) were derived from bi-exponential fitting of IVIM data obtained with 14 different b-values in three orthogonal directions. We investigated the correlation between D, f, and D* and model-free parameters from the DCE-MRI (wash-in, Tmax, Emax, initial AUC60, whole AUC) and the apparent diffusion coefficient (ADC) value in the tumor and normal masseter muscle using a whole volume-of-interest approach. Pearson's correlation test was used for statistical analysis. RESULTS: No correlation was found between f or D* and any of the parameters from the DCE-MRI in all patients or in patients with squamous cell carcinoma (p > 0.05). The ADC was significantly correlated with D values in the tumors (p 0.05, respectively). CONCLUSION: Intravoxel incoherent motion shows no significant correlation with model-free perfusion parameters derived from the DCE-MRI but is feasible for the analysis of diffusivity in both tumors and normal muscles of the head and neck.

Role of the dynamic contrast-enhanced MRI in assessing the response to neoadjuvant chemotherapy of breast cancer / 中国癌症杂志

Background and purpose:Neoadjuvant chemotherapy to breast cancer has become a mature treat-ment method. The purpose of this study was to evaluate the dynamic contrast-enhanced MRI in assessing the response to neoadjuvant chemotherapy (NAC).Methods:Twenty-four female patients with breast carcinoma (24 were all inva-sive ductal carcinoma) underwent dynamic contrast-enhanced MRI (DCE-MRI) before, after the second and ifnal cycle of NAC. For each patient and each MRI examination, the maximum diameter of tumor, volume transfer constant (Ktrans), exchange rate constant (Kep), and extravascular extracellular volume fraction (Ve) were compared. According to the method of response evaluation criteria in solid tumor (RECIST), the results of neoadjuvant chemotherapy were divided into responder and non-responder.Results:All 24 patients were unilateral and single breast cancer; there were 17 cases of responders and 7 cases of non-responders according to RECIST criteria. For 17 cases of responders, both the average values ofKtrans andKepwere signiifcantly descended after neoadjuvant chemotherapy (allP<0.05).Conclusion:The quantitative parameters ofKtrans andKep can evaluate objectively and veridically the response to neoadjuvant chemother-apy for breast cancer in dynamic contrast-enhanced MRI.

The value of dynamic contrast-enhanced MRI in the assessment of cervical cancer at 3.0T / 实用放射学杂志

Objective To evaluate the value of dynamic contrast-enhanced MRI (DCE-MRI)in the assessment of cervical cancer with different features.Methods A cohort study of 1 56 cervical cancer patients underwent routine MRI and DCE-MRI scanning on 3.0T MR unit.The semi-quantitative parameters from time-signal curve of DCE-MRI were divided into the following groups:1 ) squamous carcinoma and adenocarcinoma.2)different pathologic grades of cervical cancer (G1,G2,G3).3)early stage (FIGOⅠb/Ⅱa)tumor and advanced tumor (FIGOⅡb,Ⅲ and Ⅳ).4)cervical cancer with different lymph node status (no/yes).5)cervical cancer with dif-ferent tumor size (greatest diameter 4 cm).6)cervical cancer with different age range.Statistical analysis was performed with the data analysis program SPSS and R3.1.1.Results There was a statistically significant difference between the squamous carcinoma and adenocarcinoma in the SI30s% and Slope,as well as between the tumor FIGO early and advanced stage in TTP and Slope.There was no significant difference among other groups.Conclusion The semi-quantitative parameters from time-signal curve of DCE-MRI can be used to differentiate histologic type and FIGO early/advanced stage of cervical cancer.The diagnostic accuracy may be high for Slope for histologic type differentiation,and the diagnostic accuracy is equal for TTP and Slope in differenti-ation of FIGO early and advanced stage of cervical cancer.

The value of DCE-MRI quantitative parameters in the differential diagnosis of hepatocellular carcinoma from benign liver tumors / 实用放射学杂志

Objective To study the values of quantitative parameters of DCE-MRI in diagnosis of benign and malignant liver tumors and to explore its diagnostic efficacy.Methods Consecutive 25 patients with benign or malignant liver tumors underwent plain scanning and dynamic contrast-enhanced MRI,and total 28 lesions were confirmed by pathology or follow-up.The DCE-MRI quantitative parameters (Ktrans ,Kep ,Ve and iAUC)of the lesions and the surrounding normal liver tissue were acquired.The inde-pendent sample t test was used to compare the quantitative parameters between different tumors.The optimal parameters values of benign and malignant liver tumors were determined by plotting ROC curves.Results The mean quantitative parameters of HCC and benign lesions were larger than those of the surrounding normal liver tissue.Ktrans ,Kep and iAUC between HCC and surrounding nor-mal liver tissue had significant differences (P <0.05),Ktrans and iAUC between benign lesions and surrounding normal liver tissue had a significant difference (P <0.05).Ktrans ,Kep and iAUC between HCC and benign lesions had significant differences (P <0.05). The diagnostic effectiveness of Ktrans = 0.21 5 min-1 ,with sensitivity of 81.3% and specificity of 66.7%,was greater than that of Kep =0.477 and iAUC=24.706.Conclusion The DCE-MRI quantitative analysis can provide a reference for the differential diagnosis of HCC from benign liver tumors.

Diagnostic Performance of Diffusion-weighted Imaging for Hepatic Neuroendocrine Tumor: Comparison with Combined Diffusion-weighted Imaging and Contrast-enhanced Magnetic Resonance Imaging

BACKGROUND/AIMS: To investigate the diagnostic performance of diffusion-weighted imaging (DWI) for hepatic neuroendocrine tumors (NET) compared with combined DWI and contrast-enhanced magnetic resonance imaging (MRI). METHODS: Fifteen patients with hepatic NET (n=128) underwent enhanced MRI and DWI with multiple-b values. We analyzed three different sets: Precontrast set; DWI set (added DWI); combined set (added enhanced image). Two reviewers rated possibility of NET using a 5-point scale for each image set. Their diagnostic performance was compared using Jackknife alternative free-response ROC (JAFROC). RESULTS: Diagnostic performance was better on the combined set (figure of merit [FOM]=0.852, 0.761) than the precontrast set (FOM=0.427, 0.572, P〈0.05) and the DWI set (FOM=0.682, 0.620, P〈0.05). However, DWI improved performance compared with precontrast set without statistical difference. In small NETs (〈1 cm), all sets showed low sensitivity (10.7-65.9%) with high specificity (95.4-100%). Interobserver agreement was moderate in all image sets (k=0.521 to 0.589). CONCLUSIONS: Combined DWI and enhanced MRI were more useful for detecting NET. Although statistically insignficant, there was a trend in improved diagnostic performance with DWI.

Treatment Response Evaluation of Breast Cancer after Neoadjuvant Chemotherapy and Usefulness of the Imaging Parameters of MRI and PET/CT

This study was aimed to evaluate the ability of imaging parameters measured on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), diffusion-weighted MRI (DWI) and positron emission tomography/computed tomography (PET/CT) to serve as response markers in breast cancer after neoadjuvant chemotherapy (NAC). In 20 patients with breast cancer, DCE-MRI and DWI using a 3 T scanner and PET/CT were performed before and after NAC. DCE-MRI was analyzed using an automatic computer-aided detection program (MR-CAD). The response imaging parameters were compared with the pathologic response. The areas under the curve (AUCs) for DCE-MRI using MR-CAD analysis, DWI and PET/CT were 0.77, 0.59 and 0.76, respectively. The combination of all parameters measured by MR-CAD showed the highest diagnostic performance and accuracy (AUC = 0.77, accuracy = 90%). The combined use of the parameters of PET/CT with DCE-MRI or DWI showed a trend toward improved specificity and negative predictive value (100%, 100%, accuracy = 87.5%). The use of DCE-MRI using MR-CAD parameters indicated better diagnostic performance in predicting the final pathological response compared with DWI and PET/CT, although no statistically significant difference was observed. The combined use of PET/CT with DCE-MRI or DWI may improve the specificity for predicting a pathological response.

The scanning effect of the injection flow rate of contrast medium on magnetic resonance image dynamic contrast-enhanced of prostate cancer / 实用医学杂志

Objective To investigate the effect of perfusion index of the injection flow rate of contrast medium on magnetic resonance image dynamic contrast-enhanced (DCE-MRI) of prostate cancer with different pathological grades. Methods Seventy patients with PCa、cardiac, normal renal function is and BMI≤25 kg/m2 were enrolled. The 2.5 mL/s, 5.0 mL/s dynamic enhanced injection velocity contrast agent was used for 35 patients and the reast 35 patients, respectively. All data was transferred to GE Advanced Workstation 4.3, and the indexes of the peripheral prostate cancerous zone were calculated by Functool2 of signal intensity time (SI-T), The time to minimum (Tmax), the whole enhancement degree (SImax%) and the maximum slope (Rmax) were calculated. The effect of different injection velocity on the dynamic enhanced perfusion index was analyzed. Results Tmax of pa-tients received 2.5 mL/s, 5.0 mL/s contrast agent injection velocity in the low risk group (Gleason score 2 to 6)、medium risk group (7 Gleason score) and high risk group (Gleason score 8 to 10) were (19.89 ± 2.76) s and (15.42 ± 1.68) s, (16.91 ± 2.34) s and (12.88 ± 1.73) s, (14.13 ± 1.81) s and (10.2 ± 1.42) s, with signifi-cant differences (t = 4.61, 3.1, 3.25, P < 0.01). The average SImax% of PCa in the two groups were (1.45 ± 0.17)%and (1.51 ± 0.27)%, (1.62 ± 0.12)%and (1.84 ± 0.18)%, (1.86 ± 0.16)% and (2.11 ± 0.28)%, Two groups of SImax% were statistically significant difference (t = -2.44, -4.55, -5.16, P < 0.05), respectively. The average Rmax of PCa of the two groups were (6.29 ± 2.62)% and (7.64 ± 4.09)%,(8.92 ± 4.21)% and (10.24 ± 9.09)%, (10.85 ± 2.89)% and (12.43 ± 3.51)%, with significant difference (t = -4.07,-3.85, -8.68, P <0.01). Tmax was shorter, SImax% and Rmax were higher of prostate cancer patients received 5.0 mL/s contrast agent injection velocity than those received 2.5 mL/s contrast agent injection velocity. Conclusion The dynamic enhancement perfusion index of prostate cancer patients received 5.0 mL/s contrast agent injection velocity is more sensitive than that of patients received 2.5 mL/s contrast agent injection velocity , which can improve the diagnosis of prostate cancer.

Effect of Arterial Deprivation on Growing Femoral Epiphysis: Quantitative Magnetic Resonance Imaging Using a Piglet Model

OBJECTIVE: To investigate the usefulness of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion MRI for the evaluation of femoral head ischemia. MATERIALS AND METHODS: Unilateral femoral head ischemia was induced by selective embolization of the medial circumflex femoral artery in 10 piglets. All MRIs were performed immediately (1 hour) and after embolization (1, 2, and 4 weeks). Apparent diffusion coefficients (ADCs) were calculated for the femoral head. The estimated pharmacokinetic parameters (Kep and Ve from two-compartment model) and semi-quantitative parameters including peak enhancement, time-to-peak (TTP), and contrast washout were evaluated. RESULTS: The epiphyseal ADC values of the ischemic hip decreased immediately (1 hour) after embolization. However, they increased rapidly at 1 week after embolization and remained elevated until 4 weeks after embolization. Perfusion MRI of ischemic hips showed decreased epiphyseal perfusion with decreased Kep immediately after embolization. Signal intensity-time curves showed delayed TTP with limited contrast washout immediately post-embolization. At 1-2 weeks after embolization, spontaneous reperfusion was observed in ischemic epiphyses. The change of ADC (p = 0.043) and Kep (p = 0.043) were significantly different between immediate (1 hour) after embolization and 1 week post-embolization. CONCLUSION: Diffusion MRI and pharmacokinetic model obtained from the DCE-MRI are useful in depicting early changes of perfusion and tissue damage using the model of femoral head ischemia in skeletally immature piglets.

The correlation between DWI and DCE MR of normal sacroiliac joint / 实用放射学杂志

Objective To study the correlation between the ADC value and Fenh value,Senh value based on DWI and DCE-MRI, by measuring them in sacroiliac joint bone marrow of healthy volunteers.Methods 21 healthy volunteers performing the sacroiliac joint MR were involved.ADC value based on DWI,and TIC based on DCE-MRI were measured.The relationship of ADC values with Fenh,Senh values and peak to time,Tmax values were analyzed.Results The differences of the measured ADC values on both sides of the sacroiliac joint bone marrow region were not statistically significant (P>0.05).There were three types of TIC curve,8.3% (7/84)Ⅰ type,8.3% (7/84)Ⅱ type,83.3% (70/84)Ⅲtype;Fenh,Senh average values were within 20% 0.05).There was a positive correlation between ADC value and Fenh value in bone marrow region of sacroiliac joint.Conclusion This study determined the average value of ADC and Fenh,Senh in normal sacroiliac joint bone marrow area,the positive correlation between ADC value and Fenh value is a new thought and may be a new method of diagnosising the early disease of sacroiliac joint.

Permeability Parameters Measured with Dynamic Contrast-Enhanced MRI: Correlation with the Extravasation of Evans Blue in a Rat Model of Transient Cerebral Ischemia

OBJECTIVE: The purpose of this study was to correlate permeability parameters measured with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) using a clinical 3-tesla scanner with extravasation of Evans blue in a rat model with transient cerebral ischemia. MATERIALS AND METHODS: Sprague-Dawley rats (n = 13) with transient middle cerebral artery occlusion were imaged using a 3-tesla MRI with an 8-channel wrist coil. DCE-MRI was performed 12 hours, 18 hours, and 36 hours after reperfusion. Permeability parameters (K(trans), v(e), and v(p)) from DCE-MRI were calculated. Evans blue was injected after DCE-MRI and extravasation of Evans blue was correlated as a reference with the integrity of the blood-brain barrier. Correlation analysis was performed between permeability parameters and the extravasation of Evans blue. RESULTS: All permeability parameters (K(trans), v(e), and v(p)) showed a linear correlation with extravasation of Evans blue. Among them, K(trans) showed highest values of both the correlation coefficient and the coefficient of determination (0.687 and 0.473 respectively, p < 0.001). CONCLUSION: Permeability parameters obtained by DCE-MRI at 3-T are well-correlated with Evans blue extravasation, and K(trans) shows the strongest correlation among the tested parameters.

Experimental study on early effects of bevacizumab evaluated by dynamic enhanced magnetic resonance imaging / 中华消化杂志

Objective To explore the feasibility and value of dynamic contrast-enhanced (DCE-MRI) parameters in assessing early effects of anti-angiogenesis medicine in targeted therapy for tumors.Methods Twenty BALB/C-nu nude mice were injected subcutaneously with human colon cancer cells HT-29 to the right hind leg.The nude mice were evenly divided into the experimental group and control group with 10 mice in each group.The mice of experimental group were intraperitoneally injected with bevacizumab,and the control group were injected with the same volume of saline.DCE-MRI was performed before medication and one hour,24 h and 48 h after medication.The Ktrans,Kep,Ve and initial area under enhancement curve (iAUC) of DCE-MRI were analyzed.The animals were sacrificed 48 hours after medication.Microvessel density (MVD) of the tumors was detected by immunohistochemistry.One way analysis of variance was performed to analyze parameters of DCE-MRI.The Pearson correlation coefficient was used to analyze the correlation between parameters of DCE-MRI and MVD.Results Under DCE-MRI,the edge of subcutaneous colon cancer xenografts was obviously gradually enhanced,pseudo color indicated high perfusion,the strength degree of the central region was low and which meant low perfusion.The differences in Kep of different time point of experimental group were statistically significant (F=3.752,P=0.016) ; there as no significant difference in other parameters of DCE MRI (all P＞0.05).There was no significant difference in Ktrans and Kep before medication and one hour after medication (all P＞0.05).There were significant difference in Ktrans and Kep 24 hour and 48 hour after medication between experimental group (24 hour∶ (0.095 ± 0.039) min-1 and (0.297 ± 0.141) min-1,48 hour∶ (0.090±0.033) min 1 and (0.314±0.148) min-1) and control group (24 hour∶ (0.150±0.074) nin-1 and (0.494±0.126) min-1,48 hour∶ (0.171±0.045) min-1 and (0.441± 0.092) min-1) (F24h =4.824 and 11.386,F48h =22.605 and 5.455,all P＜0.05).There was no significant difference in Ve and iAUC between two groups at different time points (all P＜0.05).MVD of experimental group was lower than that of control group.Ktrans and Kep were positively correlated with MVD (r=0.745 and 0.400,both P＜0.05).Conclusion Ktrans and Kep parameters of DCE-MRI may be used in monitoring the earlier effects of anti-angiogenesis medicine in targeted therapy for colon cancer.

Evaluation of volume transfer coefficient (Ktrans)in differentiating brain metastasis from high-grade gliomas / 实用放射学杂志

Objective To determine whether volume transfer coefficient (Ktrans )can be used to differentiate high-grade glioma (HGG)and metastasis.Methods Thirty-nine patients with brain tumors (12 HGG,27 metastases)underwent dynamic contrast en-hanced MR imaging before surgical resection or stereotactic biopsy.Images were acquired with a three-dimensional (3D)fast gradi-ent echo sequence.Gadolinium-based contrast agent was injected intravenously with dosage of 0.1 mmol/kg bodyweight at a rate of 3.0 mL/s.Ktrans and Ve were calculated from the DCE MRI data.The results of Ktrans and Ve were compared between the 2 types of tumors.Receiver operating characteristic curve analysis was performed for each of the variables in differentiation cerebral metastasis from HGG.Results The Ktrans values in the parenchyma of HGG and metastases were 0.10 (0.11,0.71)min-1 and 0.21 (0.05, 0.77)min-1 ,respectively.The difference was not statistically significant (P>0.05).The Ktrans values in the peritumoral region of the HGG and brain metastasis were 0.04 (0.01,0.10)min-1 and 0.01 (0.00,0.06)min-1 ,respectively.There was a significant difference between the Ktrans values in the peritumoral edema of HGG and cerebral metastases (P<0.05).The optimal cutoff value of Ktrans for differentiating HGG from cerebral metastases was 0.03,with sensitivity of 75% and specificity of 70%.Conclusion Ktrans values in the peritumoral edema may be useful in the differentiating cerebral metastases between HGG.

Glioma Grading Capability: Comparisons among Parameters from Dynamic Contrast-Enhanced MRI and ADC Value on DWI

OBJECTIVE: Permeability parameters from dynamic contrast-enhanced MRI (DCE-MRI) and apparent diffusion coefficient (ADC) value on diffusion-weighted imaging (DWI) can be quantitative physiologic metrics for gliomas. The transfer constant (Ktrans) has shown efficacy in grading gliomas. Volume fraction of extravascular extracellular space (ve) has been underutilized to grade gliomas. The purpose of this study was to evaluate ve in its ability to grade gliomas and to assess the correlation with other permeability parameters and ADC values. MATERIALS AND METHODS: A total of 33 patients diagnosed with pathologically-confirmed gliomas were examined by 3 T MRI including DCE-MRI and ADC map. A region of interest analyses for permeability parameters from DCE-MRI and ADC were performed on the enhancing solid portion of the tumors. Permeability parameters form DCE-MRI and ADC between low- and high-grade gliomas; the diagnostic performances of presumptive metrics and correlation among those metrics were statistically analyzed. RESULTS: High-grade gliomas showed higher Ktrans (0.050 vs. 0.010 in median value, p = 0.002) and higher ve (0.170 vs. 0.015 in median value, p = 0.001) than low-grade gliomas. Receiver operating characteristic curve analysis showed significance in both Ktrans and ve for glioma grading. However, there was no significant difference in diagnostic performance between Ktrans and ve. ADC value did not correlate with any of the permeability parameters from DCE-MRI. CONCLUSION: Extravascular extracellular space (ve) appears to be comparable with transfer constant (Ktrans) in differentiating high-grade gliomas from low-grade gliomas. ADC value does not show correlation with any permeability parameters from DCE-MRI.

Dynamic Contrast-Enhanced MR Imaging in Detecting Local Tumor Progression after HIFU Ablation of Localized Prostate Cancer

PURPOSE: To retrospectively evaluate the diagnostic performance of dynamic contrast-enhanced MR imaging (DCE-MRI) in detecting recurrent prostate cancer after HIFU of clinically localized cancer, as compared with T2-weighted imaging (T2WI). MATERIALS AND METHODS: Twenty-six patients with increased prostate-specific antigen levels after HIFU were included in this study. All MR examinations were performed using T2WI and DCE-MRI, followed by transrectal ultrasound-guided biopsy. MRI and biopsy results were correlated in six prostate sectors. Residual or recurrent cancer after HIFU was defined as local tumor progression if biopsy results showed any cancer foci. Two independent readers interpreted the MR images. RESULTS: Of 156 prostate sectors, 51 (33%) were positive for cancer in 17 patients. For detecting local tumor progression, the sensitivity of DCE-MRI and T2WI was 80% and 57% for reader 1 (P 0.05). Interobserver agreement of DCE-MRI and T2WI was moderate and fair, respectively. CONCLUSION: For detecting local tumor progression of prostate cancer after HIFU, DCE-MRI was more sensitive than T2WI, with less interobserver variability.