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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.
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Adult , Humans , Retrospective Studies , Magnetic Resonance Imaging , Plasma , Tomography, X-Ray Computed , LungABSTRACT
@#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.
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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.
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Artifacts , Hand Strength , Image Processing, Computer-Assisted , Liver , Magnetic Resonance Imaging , MethodsABSTRACT
Para determinar la existencia de compromiso parenquimatoso renal en infección del tracto urinario en niños, la tendencia actual es utilizar métodos de imágenes lo menos invasivos posibles, disminuyendo al máximo la exposición a radiación ionizante. La resonancia magnética ha demostrado utilidad en la pesquisa de pielonefritis aguda. Desarrollamos por esto un protocolo de resonancia magnética (PieloRM), que permite de manera rápida, segura y no invasiva detectar compromiso inflamatorio parenquimatoso renal, eventuales complicaciones y alteraciones anatómicas preexistentes. Se utilizan secuencias anatómicas potenciadas en T2 y difusión en los planos axial y coronal en el eje largo de los riñones, sin contraste endovenoso ni anestesia, con técnica de privación de sueño, abrigar y alimentar en lactantes y niños más pequeños. La duración total del examen no sobrepasa los 15 minutos.
Current trend to determine kidney involvement in urinary tract infection in children consider less invasive and lower radiation exposure. Magnetic resonance has been reported has a useful tool in acute pyelonephritis suspicion. We developed a fast, safety, non-contrast magnetic resonance protocol to detect renal parenchymal inflammatory changes in children. Complications and anatomical alterations were also possible to be evaluated. Axial and coronal T2-weighted images for anatomical characterization and diffusion weighted images were obtain for kidney representation. Feed and wrap technique and sleep deprivation, with non-additional sedation or anesthesia was used in a 15 minutes total examination protocol.
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Humans , Female , Child , Pyelonephritis/diagnostic imaging , Magnetic Resonance Imaging/methods , Acute DiseaseABSTRACT
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.
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Humans , Brain Neoplasms , Brain , Magnetic Resonance Imaging , Neoplasm Metastasis , Relaxation , Tumor BurdenABSTRACT
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.
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Objective:To observe and research the diagnostic value of enhanced MRI of pituitary for pituitary stalk interruption syndrome (PSIS) and explore the correlation between enhanced MRI and pituitary target gland function damage.Methods: 80 patients with PSIS were divided into part of pituitary stalk interruption group (38cases) and complete pituitary stalk interruption group (42cases). And 80 healthy people were divided into control group. The relative hormonal level of three groups were detected, and the correlation between appearance of MRI and insufficient hormonal type, amount and severity degree were analyzed.Results: In part of pituitary stalk interruption group, the heights of anterior pituitary gland were less than 3mm in 10 cases, and they were between 3-5mm in 23 cases and they were more than 5mm in 5 cases. And in them, there were 4 cases were posterior pituitary deficiency, 15 cases were heterotopia, 11 cases were volume diminished. In complete pituitary stalk interruption group, the heights of anterior pituitary gland were less than 3mm in 23 cases, and they were between 3-5mm in 16 cases and they were more than 5mm in 3 cases. And in them, there were 8 cases were posterior pituitary deficiency, 32 cases were heterotopia, 1 cases were volume diminished. All of the hormonal levels included growth hormone, insulin-like growth factor, free thyroxine, serum thyroid stimulating hormone (TSH), cortisol and adrenocorticotrophic hormone (ACTH) in complete pituitary stalk interruption group were significantly lower than that in part of pituitary stalk interruption group and control group (F=224.92,F=2571.80, F=369.50,F=67.73,F=2677.94,F=24.17,P<0.05), respectively. The differences of growth hormone, TSH, cortisol and ACTH, excepted insulin-like growth factor and free thyroxine, between part of pituitary stalk interruption group and control group were not significant. And pituitary-gonadal hormones level of part of pituitary stalk interruption group was significantly lower than that of control group (F=354.94,F=247.00, F=247.83,F=655.05,F=48.10,P<0.05). Besides, the differences of follicle-stimulating hormone, luteinizing hormone, estradiol, testosterone and prolactin levels between part of pituitary stalk interruption group and complete pituitary stalk interruption group were no significant.Conclusion: Enhanced MRI of pituitary can effectively diagnose pituitary stalk interruption syndrome and damage degree of pituitary target gland function.
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No abstract available.
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Adult , Humans , Male , Middle Aged , Anterior Temporal Lobectomy , Bile Duct Neoplasms/diagnostic imaging , Bile Ducts, Intrahepatic/surgery , Carcinoma, Hepatocellular/diagnostic imaging , Cholangiocarcinoma/diagnostic imaging , Cholangiopancreatography, Magnetic Resonance , Diagnosis, Differential , Liver/diagnostic imaging , Liver Neoplasms/diagnostic imaging , Magnetic Resonance Imaging , Tomography, X-Ray ComputedABSTRACT
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.
Subject(s)
Humans , Carcinoma, Squamous Cell , Diffusion , Head , Magnetic Resonance Imaging , Masseter Muscle , Muscles , Neck , Perfusion , Retrospective StudiesABSTRACT
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.
Subject(s)
Humans , Magnetic Resonance Imaging , Neuroendocrine Tumors , Sensitivity and SpecificityABSTRACT
MI is often associated with cardiac arrhythmias,and ventricular arrhythmia is the most common.MRI is a powerful tool for the assessment of myocardial viability,DE-MRI detection of myocardial scar is the gold standard for diagnosis myocardial infarction,Now we summarized the detection of myocardial infarction scar by DE-MRI and the relationship between myocardial infarction scar and ventricular arrhythmia.
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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.
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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.
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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.
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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.
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Animals , Rats , Behavior Rating Scale , Blood-Brain Barrier , Brain , Infarction, Middle Cerebral Artery , Ischemia , Ischemic Attack, Transient , Magnetic Resonance Imaging , Middle Cerebral Artery , Models, Animal , Neutrophils , Permeability , Peroxidase , Reperfusion , Rotarod Performance TestABSTRACT
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.
Subject(s)
Adult , Aged , Female , Humans , Middle Aged , Antineoplastic Agents/therapeutic use , Breast Neoplasms/diagnosis , Chemotherapy, Adjuvant/methods , Image Interpretation, Computer-Assisted/methods , Magnetic Resonance Imaging/methods , Mammography/methods , Multimodal Imaging/methods , Neoadjuvant Therapy/methods , Positron-Emission Tomography/methods , Reproducibility of Results , Retrospective Studies , Sensitivity and Specificity , Tomography, X-Ray Computed/methods , Treatment OutcomeABSTRACT
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.
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Animals , Male , Rats , Blood-Brain Barrier/pathology , Capillary Permeability , Contrast Media , Disease Models, Animal , Evans Blue/analysis , Ischemic Attack, Transient/diagnosis , Magnetic Resonance Imaging/instrumentation , Rats, Sprague-Dawley , Stroke/diagnosisABSTRACT
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.
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Animals , Male , Arteries/physiopathology , Diffusion Magnetic Resonance Imaging/methods , Disease Models, Animal , Embolism/complications , Epiphyses/blood supply , Femur Head/blood supply , Osteonecrosis/pathology , Pelvic Bones/blood supply , Reperfusion Injury/complications , SwineABSTRACT
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.
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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.