High-resolution Isotropic Volume Excitation Research Articles

Diagnostic Model for Proliferative HCC Using LI-RADS: Assessing Therapeutic Outcomes in Hepatectomy and TKI-ICI Combination.

Proliferative hepatocellular carcinoma (HCC), aggressive with poor prognosis, and lacks reliable MRI diagnosis. To develop a diagnostic model for proliferative HCC using liver imaging reporting and data system (LI-RADS) and assess its prognostic value. Retrospective. 241 HCC patients underwent hepatectomy (90 proliferative HCCs: 151 nonproliferative HCCs), divided into the training (N = 167) and validation (N = 74) sets. 57 HCC patients received combination therapy with tyrosine kinase inhibitors (TKIs) and immune checkpoint inhibitors (ICIs). 3.0 T, T1- and T2-weighted, diffusion-weighted, in- and out-phase, T1 high resolution isotropic volume excitation and dynamic gadoxetic acid-enhanced imaging. LI-RADS v2018 and other MRI features (intratumoral artery, substantial hypoenhancing component, hepatobiliary phase peritumoral hypointensity, and irregular tumor margin) were assessed. A diagnostic model for proliferative HCC was established, stratifying patients into high- and low-risk groups. Follow-up occurred every 3-6 months, and recurrence-free survival (RFS), progression-free survival (PFS) and overall survival (OS) in different groups were compared. Fisher's test or chi-square test, t-test or Mann-Whitney test, logistic regression, Harrell's concordance index (C-index), Kaplan-Meier curves, and Cox proportional hazards. Significance level: P < 0.05. The diagnostic model, incorporating corona enhancement, rim arterial phase hyperenhancement, infiltrative appearance, intratumoral artery, and substantial hypoenhancing component, achieved a C-index of 0.823 (training set) and 0.804 (validation set). Median follow-up was 32.5 months (interquartile range [IQR], 25.1 months) for postsurgery patients, and 16.8 months (IQR: 13.2 months) for combination-treated patients. 99 patients experienced recurrence, and 30 demonstrated tumor nonresponse. Differences were significant in RFS and OS rates between high-risk and low-risk groups post-surgery (40.3% vs. 65.8%, 62.3% vs. 90.1%, at 5 years). In combination-treated patients, PFS rates differed significantly (80.6% vs. 7.7% at 2 years). The MR-based model could pre-treatment identify proliferative HCC and assist in prognosis evaluation. Stage 2.

Comparison of gadolinium-based contrast agents for MR cholangiography in saline, blood and bile: a phantom study

BackgroundWe compared T1- and T2-weighted signal intensities of liver-specific (gadoxetate, gadobenate) and non-specific (gadoterate) gadolinium contrast agents (CAs) in a bile phantom.MethodsIn a phantom study, gadoxetate, gadobenate, and gadoterate were diluted in saline, blood, and bile at different concentrations (0, 0.25, 0.5. 1, 2.5, 5, 10, and 25 mM) and imaged in a 3-T magnetic resonance imaging (MRI) system using T1- and T2-weighted sequences. The maximum signal intensities of CAs were compared for each sequence separately and across all T1-weighted sequences using one-way ANOVA.ResultsUsing T1-weighted sequences, CA concentration-dependent signal intensity increase was followed by decrease due to T2* effects. Comparing CAs for each sequence in bile yielded higher maximum signal intensities with gadobenate than gadoxetate and gadoterate using T1-weighted spin-echo (p < 0.010), multiecho gradient- and spin-echo (p < 0.001), and T1-weighted high-resolution isotropic volume excitation (eTHRIVE) sequences (p < 0.010). Comparing across all T1-weighted sequences in the bile phantom, gadobenate imaged using T1-weighted turbo field-echo (TFE) sequence showed the highest signal intensity, significantly higher than that using other CAs agents or sequences (p < 0.004) except for gadobenate and gadoxetate evaluated with three-dimensional multiecho fast field-echo (3D-mFFE) and gadoxetate with T1-weighted TFE sequence (p > 0.141). Signal reduction with CA concentration-dependent decrease was observed on T2-weighted images.ConclusionIn this bile phantom study of gadolinium-based CA, gadobenate and gadoxetate showed high signal intensity with T1-weighted TFE and 3D-mFFE sequences, which supports their potential utility for contrast-enhanced hepatobiliary MRI.Key points• Contrast-enhanced magnetic resonance (MR) cholangiography depends on contrast agent type, kinetics, and concentration in bile,• We compared signal intensities of three contrast agents in a bile phantom study.• Gadobenate, gadoxetate, and gadoterate demonstrated different signal intensities at identical concentrations.• Gadoxetate and gadobenate showed high signal intensities on T1-weighted MR sequences.

Expanded transcanal transpromontorial approach for acoustic neuroma removal.

Axial sections from preoperative magnetic resonance imaging without contrast, showing a cone-shaped lesion of the internal auditory canal, extending toward the most lateral part of the cerebello-pontine angle. (A) T1-weighted high-resolution isotropic volume excitation (THRIVE) sequence; (B) T1-weighted sequence; (C) Fluid attenuated inversion recovery (FLAIR) sequence. Laryngoscope, 133:282-286, 2023.

Significance of different offending vessels and development of a potential screening tool for trigeminal neuralgia.

This study was performed amongst trigeminal neuralgia (TN) patients with neurovascular contact (NVC) to 1) investigate the association of the demographic and radiologic factors/variables with TN occurrence, and 2) develop a screening tool for TN/TN-affected nerves based on the factors/variables associated with it. Eighty-five TN patients were recruited, and 121 trigeminal nerves with NVC were derived from them. Based on MRI sequences, including balanced turbo field echo and enhanced T1 high-resolution isotropic volume excitation, radiologic factors/variables for each nerve, from the offending vessel to the presence of nerve displacement, were identified by a neuroradiologist and a neurosurgeon. Demographic and clinical data were obtained from clinical notes. Logistic regression was performed to assess the association of the factors/variables with TN occurrence (i.e., affected vs. unaffected nerves). Three factors/variables were significantly (p<0.05) associated with TN occurrence amongst patients with NVC: nerve laterality, vertebral artery (VA) involvement, and the presence of nerve displacement. The nerves with VA involvement, those on the right side, and those with nerve displacement exhibited a significantly higher likelihood/odd of being affected by TN, compared to those without VA involvement, those on the left side, and those without nerve displacement, respectively. Based on these factors/variables, a screening tool/nomogram with acceptable accuracy was established (C-statistic/AUC = 0.80). This study revealed an association of the three radiologic factors/variables with TN occurrence. A screening tool for TN/TN-affected nerves was established based on them. The findings may lay a foundation for an improvement of the diagnosis and clinical management of TN. • VA involvement and nerve displacement could be identified using MRI, and are significantly associated with TN occurrence. • A potential objective screening tool/nomogram for TN/TN-affected nerves could be established based on the three radiologic factors/variables: VA involvement, the presence of nerve displacement, and nerve laterality. • The screening accuracy of the tool/nomogram is acceptable as the C-statistic is 0.80.

Diagnostic Accuracy of 3D Contrast-Enhanced T1 High Resolution Isotropic Volume Excitation MRI for Non-Cavernous Intracranial Dural Arteriovenous Fistula

Objective: To determine the accuracy of 3D contrast-enhanced THRIVE MRI in diagnosis of non-cavernous intracranial dural AVF compared with DSA. Materials and Methods: Thirty-three patients including fourteen dural AVF cases and nineteen control subjects, were included in the present study. They underwent 3D contrast-enhanced THRIVE MRI by 3T, contrast-enhanced MRA, and DSA. Two independent readers reviewed 3D contrast-enhanced THRIVE images for the presence of transosseous arterial feeders, low signal intensity curvilinear structures in the dural venous sinus, shaggy dural sinus, and cortical venous dilatation. Diagnostic performance values were calculated for 3D contrast-enhanced THRIVE MRI. Results: The 3D contrast-enhanced THRIVE MRI identified 23 from 29 locations of dural AVFs. The overall accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were 91.4%, 79.3%, 93.5%, 67.6% and 96.3%, respectively. Shaggy dural sinus and dilated cortical veins were found in 78.6% and 85.7%, respectively. Conclusion: The 3D contrast-enhanced THRIVE MRI is a valuable tool for diagnosis of dural AVF as well as exclusion of dural AVF due to high sensitivity and specificity. Keywords: Dural arteriovenous fistula; Dural AVF; 3D contrast-enhanced THRIVE MRI

Spin-echo and diffusion-weighted MRI in differentiation between progressive massive fibrosis and lung cancer.

We aimed to investigate the value of magnetic resonance imaging (MRI)-based parameters in differentiating between progressive massive fibrosis (PMF) and lung cancer. This retrospective study included 60 male patients (mean age, 67.0±9.0 years) with a history of more than 10 years working in underground coal mines who underwent 1.5 T MRI of thorax due to a lung nodule/mass suspicious for lung cancer on computed tomography. Thirty patients had PMF, and the remaining ones had lung cancer diagnosed histopathologically. The sequences were as follows: coronal single-shot turbo spin echo (SSH-TSE), axial T1- and T2-weighted spin-echo (SE), balanced turbo field echo, T1-weighted high-resolution isotropic volume excitation, free-breathing and respiratory triggered diffusion-weighted imaging (DWI). The patients' demographics, lesion sizes, and MRI-derived parameters were compared between the patients with PMF and lung cancer. Apparent diffusion coefficient (ADC) values of DWI and respiratory triggered DWI, signal intensities on T1-weighted SE, T2-weighted SE, and SSH-TSE imaging were found to be significantly different between the groups (p < 0.001, for all comparisons). Median ADC values of free-breathing DWI in patients with PMF and cancer were 1.25 (0.93-2.60) and 0.76 (0.53-1.00) (× 10-3 mm2/s), respectively. Most PMF lesions were predominantly iso- or hypointense on T1-weighted SE, T2-weighted SE, and SSH-TSE, while most malignant ones predominantly showed high signal intensity on these sequences. MRI study including SE imaging, specially T1-weighted SE imaging and ADC values of DWI can help to distinguish PMF from lung cancer.

Prediction of Microvascular Invasion of Hepatocellular Carcinoma Based on Contrast-Enhanced MR and 3D Convolutional Neural Networks.

Background and PurposeIt is extremely important to predict the microvascular invasion (MVI) of hepatocellular carcinoma (HCC) before surgery, which is a key predictor of recurrence and helps determine the treatment strategy before liver resection or liver transplantation. In this study, we demonstrate that a deep learning approach based on contrast-enhanced MR and 3D convolutional neural networks (CNN) can be applied to better predict MVI in HCC patients.Materials and MethodsThis retrospective study included 114 consecutive patients who were surgically resected from October 2012 to October 2018 with 117 histologically confirmed HCC. MR sequences including 3.0T/LAVA (liver acquisition with volume acceleration) and 3.0T/e-THRIVE (enhanced T1 high resolution isotropic volume excitation) were used in image acquisition of each patient. First, numerous 3D patches were separately extracted from the region of each lesion for data augmentation. Then, 3D CNN was utilized to extract the discriminant deep features of HCC from contrast-enhanced MR separately. Furthermore, loss function for deep supervision was designed to integrate deep features from multiple phases of contrast-enhanced MR. The dataset was divided into two parts, in which 77 HCCs were used as the training set, while the remaining 40 HCCs were used for independent testing. Receiver operating characteristic curve (ROC) analysis was adopted to assess the performance of MVI prediction. The output probability of the model was assessed by the independent student’s t-test or Mann-Whitney U test.ResultsThe mean AUC values of MVI prediction of HCC were 0.793 (p=0.001) in the pre-contrast phase, 0.855 (p=0.000) in arterial phase, and 0.817 (p=0.000) in the portal vein phase. Simple concatenation of deep features using 3D CNN derived from all the three phases improved the performance with the AUC value of 0.906 (p=0.000). By comparison, the proposed deep learning model with deep supervision loss function produced the best results with the AUC value of 0.926 (p=0.000).ConclusionA deep learning framework based on 3D CNN and deeply supervised net with contrast-enhanced MR could be effective for MVI prediction.

Gadoxetic acid-enhanced dynamic magnetic resonance imaging using optimized integrated combination of compressed sensing and parallel imaging technique

PurposeTo evaluate the feasibility of optimized integrated combination of compressed sensing and parallel imaging technique (prototype Compressed SENSE) in gadoxetic acid-enhanced dynamic magnetic resonance (MR) imaging. Materials and methodsSixty-one patients underwent gadoxetic acid-enhanced dynamic imaging using enhanced T1 high-resolution isotropic volume excitation (eTHRIVE) with the Compressed SENSE (CS-eTHRIVE; C SENSE factor, 3.4; acquisition time, 10 s). Results were compared with 61 propensity score-matched patients who underwent conventional eTHRIVE (eTHRIVE; acquisition time, 20 s). For quantitative image analyses, signal intensity ratio (SIR) and signal-to-noise ratio (SNR), coefficient of variation (CV) of liver parenchyma were calculated in each dynamic phase. For qualitative image analyses, two radiologists rated the homogeneity of liver parenchyma, sharpness of liver edge and left external lobe, motion artifacts, and overall image quality in each dynamic phase using a five-point scale. ResultsSIRs of liver parenchyma with CS-eTHRIVE were significantly higher than with eTHRIVE in the hepatic arterial phase (HAP) (1.70 vs. 1.52) and transitional phase (TP) (2.18 vs. 2.06) (P ≤ 0.030). SNR of liver parenchyma were comparable between the two sequences in all phases. CV of liver parenchyma in HAP with eTHRIVE (0.079) was significantly higher than with CS-eTHRIVE (0.065) (P < 0.001). Motion artifacts were significantly reduced with CS-eTHRIVE compared with eTHRIVE in all phases (P ≤ 0.005). The appearance ratio of extensive motion artifacts in HAP with CS-eTHRIVE (0/61; 0%) were significantly reduced compared with eTHRIVE (4/61; 6.6%) (P = 0.042). Overall image quality with CS-eTHRIVE was significantly better than with eTHRIVE in all phases (P ≤ 0.039). ConclusionCS-eTHRIVE compared with eTHRIVE effectively reduced the acquisition time and extensive motion artifacts without degradation of image quality.

Liver volume is lower and associates with resting and dynamic blood pressure variability in chronic fatigue syndrome

ABSTRACT Background: Chronic fatigue syndrome (CFS) in many cases is characterised by abnormal autonomic function and lower blood pressure (BP). In animals the liver is a capacitance vessel for BP homeostasis. We developed a novel liver magnetic resonance (MR) imaging technique to compare liver volume in CFS to controls, and to explore its role in cardiovascular physiology. Methods: Liver MR (single breath-hold, enhanced T1-weighted, high-resolution isotropic volume excitation 3-Tesla Achieva, NL) determined liver volume. Red cell and plasma volume were also measured. A 10 min resting cardiac autonomic assessment using beat-to-beat measurement (Taskforce; CNSystems) was followed by assessment of hemodynamic response to standing to determine blood pressure drop and return to baseline. Results: Forty-four CFS patients (age = 45.5, 34f/10 m, Fukuda criteria) and 10 age, activity and sex matched controls (age = 49.4, 7f/3 m) participated. Adjusted for body size, CFS patients had significantly reduced liver volumes (775 (101) ml/m2 v 846 (96) ml/m2; p = 0.02). At rest, liver volume was unrelated to symptom severity, heart rate, BP or heart rate variability. Both increased systolic and diastolic low frequency (LF) BP variability (predominantly sympathetic) were associated with lower liver volumes. On standing, liver volume was unrelated to BP drop but was associated with successful BP return-to-baseline. Red cell and plasma volume were associated positively with liver volume. Multivariate analysis confirmed return-to-baseline BP on standing which was independently associated with liver volume. Conclusion: Liver volumes were smaller in CFS compared to controls. The relationship between return-to-baseline BP after standing and liver volume suggests, as in animals, that the liver is involved in maintenance of BP. Abbreviations: ACI: Accelerated cardiac index; BPV: Blood pressure variability; BRS: Baroreflex sensitivity; CFS: chronic fatigue syndrome; Chr: Chromium; CI: cardiac index; FIS: Fatigue impact scale; HF: High frequency; HRV: Heart rate variability; LF: Low frequency; MR: magnetic resonance; NU: normalised units; SD: Standardised deviation; PSD: power spectral density; SI: Stroke index; TPRI: Total peripheral resistance index

Preoperative 3-dimensional Magnetic Resonance Imaging of Uterine Myoma and Endometrium Before Myomectomy

Uterine myomas are the most common gynecologic benign tumor affecting women of childbearing age, and myomectomy is the main surgical option to preserve the uterus and fertility. During myomectomy for women with multiple myomas, it is advisable to identify and remove as many as possible to decrease the risk of future myomectomies. With deficient preoperative imaging, gynecologists are challenged to identify the location and size of myomas and the endometrium, which, in turn, can lead to uterine rupture during future pregnancies. Current conventional 2-dimensional imaging has limitations in identifying precise locations of multiple myomas and the endometrium. In our experience, we preferred to use 3-dimensional imaging to delineate the myomas, endometrium, or blood vessels, which we were able to successfully reconstruct by using the following imaging method. To achieve 3-dimensional imaging, we matched T2 turbo spin echo images to detect uterine myomas and endometria with T1 high-resolution isotropic volume excitation–post images used to detect blood vessels by using an algorithm based on the 3-dimensional region growing method. Then, we produced images of the uterine myomas, endometria, and blood vessels using a 3-dimensional surface rendering method and successfully reconstructed selective 3-dimensional imaging for uterine myomas, endometria, and adjacent blood vessels. A Web-based survey was sent to 66 gynecologists concerning imaging techniques used before myomectomy. Twenty-eight of 36 responding gynecologists answered that the 3-dimensional image produced in the current study is preferred to conventional 2-dimensional magnetic resonance imaging in identifying precise locations of uterine myomas and endometria. The proposed 3-dimensional magnetic resonance imaging method successfully reconstructed uterine myomas, endometria, and adjacent vessels. We propose that this will be a helpful adjunct to uterine myomectomy as a preoperative imaging technique in future studies.

Evaluation of shoulder pathology: three-dimensional enhanced T1 high-resolution isotropic volume excitation MR vs two-dimensional fast spin echo T2 fat saturation MR.

To evaluate the diagnostic accuracy of three-dimensional (3D) enhanced T1 high-resolution isotropic volume excitation (eTHRIVE) shoulder MR for the detection of rotator cuff tears, labral lesions and calcific tendonitis of the rotator cuff in comparison with two-dimensional (2D) fast spin echo T2 fat saturation (FS) MR. This retrospective study included 73 patients who underwent shoulder MRI using the eTHRIVE technique. Shoulder MR images were interpreted separately by two radiologists. They evaluated anatomic identification and image quality of the shoulder joint on routine MRI sequences (axial and oblique coronal T2 FS images) and compared them with the reformatted eTHRIVE images. The images were scored on a four-point scale (0, poor; 1, questionable; 2, adequate; 3, excellent) according to the degree of homogeneous and sufficient fat saturation to penetrate bone and soft tissue, visualization of the glenoid labrum and distinction of the supraspinatus tendon (SST). The diagnostic accuracy of eTHRIVE images compared with routine MRI sequences was evaluated in the setting of rotator cuff tears, glenoid labral injuries and calcific tendonitis of the SST. Fat saturation scores for eTHRIVE were significantly higher than those of the T2 FS for both radiologists. The sensitivity and accuracy of the T2 FS in diagnosing rotor cuff tears were >90%, whereas sensitivity and accuracy of the eTHRIVE method were significantly lower. The sensitivity, specificity and accuracy of both images in diagnosing labral injuries and calcific tendonitis were similar and showed no significant differences. The specificity of both images for the diagnosis of labral injuries and calcific tendonitis was higher than the sensitivities. The accuracy of 3D eTHRIVE imaging was comparable to that of 2D FSE T2 FS for the diagnosis of glenoid labral injury and calcific tendonitis of SST. The 3D eTHRIVE technique was superior to 2D FSE T2 FS in terms of fat saturation. Overall, 3D eTHRIVE was inferior to T2 FS in the evaluation of rotator cuff tears because of poor contrast between joint fluid and tendons. The accuracy of 3D eTHRIVE imaging is comparable to that of 2D FSE T2 FS for the diagnosis of glenoid labral injury and calcific tendonitis of SST.

MR subtraction in the differentiation of benign and malignant tumors

To evaluate dynamic contrast-enhanced MRI in conjunction with MR subtraction in the differential diagnosis of benign and malignant breast tumors at 3 Tesla. A total of 78 patients with breast tumors enrolled in this study, including 45 malignant lesions and 33 benign lesions verified by histopathology. Dynamic MR contrast enhanced imaging was done by T1 high resolution isotropic volume excitation sequence. MR subtraction was used to retrospectively analyze the MR dynamic image. A dynamic phase subtraction (DPS) map is a map image with pixel-by-pixel subtraction of an early-phase image from a delayed maximum enhancement phase image obtained in a dynamic study. The sensitivity and specificity were calculated with or without subtraction in the diagnosis of benign and malignant breast tumors. The sensitivity of benign breast masses increased from 0.879 to 0.939, and the specificity increased from 0.818 to 0.909 with reference to the DPS map. There was statistical difference between with or without DPS (Z=2.023, P=0.043). The sensitivity of breast malignant masses increased from 0.889 to 0.933, and the specificity increased from 0.867 to 0.911 with reference to the DPS map, with statistical difference between with or without DPS map (Z=2.294, P=0.021). The pattern of TIC changed from continuous to a plateau in 8 patients, from a plateau to washout in 10, and from continuous to washout in 5. No changes were observed in the other 55 patients. MR Subtraction is a simple and useful technique to identify breast lesions. It helps to accurately set the location of the ROI TIC and improve the detection rate of benign and malignant breast tumors.

Magnetic Resonance–Guided Freehand Radiofrequency Ablation of Malignant Liver Lesions

The aims of this study were to develop magnetic resonance (MR)-guided freehand radiofrequency ablation (RFA) using a near-real-time interactive MR platform in an open 1.0-T MR scanner and to determine the feasibility and safety of this new approach in the clinical setting. The study was performed using an open 1.0-T MR system and a low-pass filter to prevent interaction between the RFA generator and the scanner. Artifact size of the radiofrequency needle was measured in 2 perpendicular views (transversal [tra] and coronal [cor]) in vitro and in the tra orientation in vivo for diagnostic (T1 high resolution isotropic volume excitation [THRIVE]/T2 turbo spin-echo [TSE]) and near-real-time (T1 fast-field-echo [FFE]) imaging. A liver-specific contrast medium (gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid) was administered 20 minutes before the intervention to enhance lesion visibility. Visibility was rated and compared for both interventional and diagnostic imaging sequences using a 10-point grading scale. Intervention time and complications were recorded. The mean diameter of needle artifact size for interventional T1 FFE was 17.4 ± 0.7 mm (tra) and 17.1 ± 1.1 mm (cor) in vitro and 15.2 ± 1.5 mm (tra) in vivo. Artifact size for diagnostic imaging was 12.5 ± 1.8 mm (tra) and 11.2 ± 1.4 mm (cor) in vitro and 10.5 ± 1.7 mm in vivo using THRIVE and 8.1 ± 2.4 mm (tra) and 10.8 ± 1.8 mm (cor) in vitro and 9.7 ± 2.0 mm (tra) in vivo using T2 TSE. A total of 57 patients with liver malignancies (mean tumor size, 17 ± 7 mm) underwent freehand MR-guided RFA. In all patients, the ablative procedure was technically successful. Lesion visibility of the diagnostic T2 TSE sequence (4 ± 2) was significantly decreased compared with both the diagnostic (THRIVE, 7 ± 2) and interventional (T1 FFE, 8 ± 1) T1-weighted sequences. Mean time to position the applicator was 7.5 ± 2 minutes. Procedure times ranged from 30 to 60 minutes. The mean in-room time was 57 ± 22 minutes. No major complications were recorded. Magnetic resonance-guided freehand RFA using a near-real-time interactive MR platform in an open 1.0-T MR scanner is feasible, safe, and applicable in clinical routine. The administration of a hepatocyte-specific contrast agent enhances lesion visualization and therefore improves targeting. Without the need for additional sophisticated devices, this new approach simplifies and shortens the RFA procedure compared with previously published methods.

Assessment of activity of Crohn’s disease of the ileum and large bowel: proposal for a new multiparameter MR enterography score

We evaluated the diagnostic accuracy of magnetic resonance enterography (MR-E) in assessing Crohn's disease (CD) activity by differentiating acute, chronic and remission stages of disease through a quantitative MR-E assessment. One hundred patients with a histological diagnosis of CD were studied with MR-E. Intestinal distension was obtained by oral administration of approximately 2 L of a polyethylene glycol solution (PEG). In all cases, the ileum and large bowel were imaged with morphological sequences (heavily T2-weighted single-shot, dual fast-field echo, balanced fast-field echo) and a postcontrast dynamic sequence (T1-weighted high-resolution isotropic volume excitation). Disease activity was assessed according to a multiparameter score (0-8) based on lesion morphology, signal intensity and contrast enhancement. MR-E findings were compared with clinical-laboratory data and disease activity indices [Crohn's Disease Activity Index (CDAI); Inflammatory Bowel Disease Questionnaire (IBDQ)]. Multiple regression analysis was performed by correlating MR-E score, CDAI and IBDQ. Frequencies were then compared using the χ (2) test. MR-E identified inactive disease in 9% of cases, chronic disease in 57% and active disease in the remaining 34%. The most frequently involved bowel segment was the terminal ileum (52%). A statistically significant correlation was found between MR-E score and CDAI (R=0.86; p<0.001) and between MR-E score and IBDQ (R=-0.83; p<0.001). The most suggestive parameter for disease activity was layered bowel-wall enhancement, a finding predominantly present in patients with increased CDAI (≥ 150) and/or local complications (χ (2)=7.13; p<0.01). MR-E is a noninvasive and diagnostic imaging modality for CD study and follow-up. The MR-E score proposed in this study proved to be useful in assessing disease severity and monitoring response to treatment.

Magnetic resonance colonography: comparison between T1 high-resolution isotropic volume excitation (THRIVE) and balanced fast field echo (bFFE) using an air enema or water–gadolinium enema

Magnetic resonance colonography: comparison between T1 high-resolution isotropic volume excitation (THRIVE) and balanced fast field echo (bFFE) using an air enema or water–gadolinium enema

Interstitial high-resolution MR lymphangiography in patients with lower extremity lymphedema

To assess the feasibility of interstitial magnetic resonance lymphangiography (IMRL) with intracutaneous injection of gadobenate dimeglumine--a commercially available, non-ionic, extracellular paramagnetic contrast agent. We studied 10 patients with lower extremity lymphedema. A mixture of 7.5 ml gadobenate dimeglumine and 0.5 ml 2% lidocaine were evenly subdivided into 8 portions and injected intracutaneously into each web space of both feet. For IMRL, a 3D fast spoiled gradient-recalled echo T1-weighted images with a fat saturation technique (T1 high resolution isotropic volume excitation, THRIVE) was performed. The beaded appearance of lymphatic vessels extending from the injection site were detected in 11 of 12 lower legs and the best delineation of lymphatic vessels was present at 15-30 minutes after injection. In 6 of 12 affected thighs, lymphatic vessels could be also visualized with the strongest enhancement at 45 minutes. IMRL is a safe and technically feasible new method which can effectively visualize the pathological lymphatic vessels in lower extremity lymphedema.