Gadobenate Dimeglumine Injection Research Articles

Impaired Glymphatic Transport Kinetics Following Induced Acute Ischemic Brain Edema in a Mouse pMCAO Model.

BackgroundCerebral edema forms immediately after blood flow interruption in ischemic stroke, which largely increased the death and disability. The glymphatic (glial-lymphatic) pathway is a major regulator of the brain liquid dynamics and homeostasis. This study aimed to investigate the transport kinetics of the glymphatic system after the appearance of ischemic edema.MethodsIn this study, a coated filament was attached to the left middle cerebral artery (MCA) of mice to establish a mouse model of permanent middle cerebral artery occlusion with an intact blood-brain barrier (BBB). The glymphatic function was then quantified using contrast-enhanced MRI (11.7T) by employing an injection of gadobenate dimeglumine (BOPTA-Gd) into the cisterna magna of mice. We then evaluated the expression and polarization of aquaporin-4 (AQP4) as a proxy for the physiological state of the glymphatic system.ResultsOur results revealed a positive correlation between the signal intensity in T1-weighted images and the corresponding apparent diffusion coefficient (ADC) values in the cortex, striatum, and periventricular zone, suggesting that impaired glymphatic transport kinetics in these regions is correlated to the cytotoxic edema induced by the occlusion of MCA. Furthermore, the increased depolarization of AQP4 in the parenchyma perivascular space (PVS) was consistent with glymphatic failure following the induced early cerebral ischemic edema.ConclusionsGlymphatic transport kinetics were suppressed between the onset of cytotoxic edema and the disruption of the BBB, which correlated with the diminishing ADC values that vary based on edema progression, and is associated with depolarization of AQP4 in the parenchyma PVSs.

Biliary excretion of gadobenate dimeglumine causing degradation of magnetic resonance cholangiopancreatography (MRCP)

To assess the effect of gadobenate dimeglumine on magnetic resonance cholangiopancreatography (MRCP) and determine an appropriate time frame for performing MRCP sequences. 2D MRCP sequences obtained after intravenous administration of gadobenate dimeglumine or gadobutrol over 14months were reviewed retrospectively in randomized order by five abdominal radiologists, using a 3-point scale to rate biliary and pancreatic duct clarity (1 = no-, 2 = limited-, 3 = good visualization). Intraclass correlation coefficients were computed and mean scores were compared for both agents. For gadobenate dimeglumine exams, time delays between arterial phase and MRCP acquisition times were analyzed concerning duct clarity. For gadobutrol, only exams with delays ≥ 15min were included. 134 exams (107 gadobenate dimeglumine, 27 gadobutrol) were included. Moderate reliability for pancreatic duct visualization and excellent reliability for visualization of intrahepatic bile ducts and upper and lower extrahepatic bile ducts were noted. No difference in mean scores was noted for pancreatic duct visualization (p = 0.66). Bile duct segment scores were lower with gadobenate dimeglumine (mean: 2.1-2.6) compared with gadobutrol (mean: 2.8-2.9) (p ≤ 0.006). For gadobenate dimeglumine, visualization scores varied depending on the delay between the arterial phase and MRCP acquisition (p ≤ 0.047). Good visualization for all bile duct segments was noted with delays of 7.2-9.4min (95% confidence interval; mean 8.3min). Bile duct clarity degraded on MRCP images with an increasing delay following gadobenate dimeglumine injection. 2D MRCP, thus, should be performed within 7.2min after obtaining the arterial phase sequence to ensure good visualization of the entire biliary system.

High-resolution MR lymphangiography for planning lymphaticovenous anastomosis treatment: a single-centre experience.

This article illustrates the feasibility of MR lymphangiography (MRL) for imaging lymphatic vessels in patients with lymphedema, its accuracy in distinguishing lymphatic vessels from veins, and its utility for planning Lymphaticovenous anastomosis (LVA) treatment. We prospectively enrolled 30 patients (24 women, range 18-70, 17 cases of lower limb lymphedema, 6 cases of primary lymphedema). All the patients underwent MRL, using a 1.5T MR unit (Signa Twin Speed Hdxt; GE), after the subcutaneous injection of gadobenate dimeglumine (Gd-BOPTA) with a little dose of lidocaine into the interdigital webs of the dorsal foot or hand. Lymphatic vessels identified for the LVA at MRL were histologically confirmed after surgery. Enhancement of lymphatic vessels and veins at different times after injection of contrast medium and their diameters were measured. A total of 79 lymphatic vessels were clearly identified in 29 patients at MRL; their morphology was tortuous in 22 patients and rectilinear in 7, whereas, the adjacent veins were straight with focal bulging only at the level of venous valve; the enhancement kinetic of the two different structures were different (p<0.05) but the mean diameter of affected lymphatic vessels was similar to the adjacent veins (p>0.05). Thirty-four out of 38 specimens of presumed lymphatic vessels at MRL, collected during surgery, resulted positive at the immunoistochemical marker d2-40, with a significant association (Chi-square=40.421, DF=1, p<0.05, contingency coefficent 0.644). One patient had an early complication 1month after treatment. MRL is easy and safe to use and combines extensive information on the anatomy and functionality of lymphatic vessels and veins in a single process; therefore, it could be useful in LVA treatment planning and evaluating possible super-microsurgical treatment complications in patients with lymphedema.

The value of Gd-BOPTA- enhanced MRIs and DWI in the diagnosis of intrahepatic mass-forming cholangiocarcinoma.

The aim of this study is to explore the value of unenhanced magnetic resonance imaging (MRI), gadobenate dimeglumine injection (Gd-BOPTA)-enhanced MRI and diffusion-weighted imaging (DWI) in the diagnosis of intrahepatic mass-forming cholangiocarcinoma (IMCC). Totally 59 IMCC patients who underwent Gd-BOPTA-enhanced MRIs were recruited. The time-signal intensity curves and lesion periphery enhancement rates of the IMCC and liver parenchyma was drawn using apparent diffusion coefficient (ADC) values. The Gd-BOPTA-enhanced MRI showed that the peripheries of 30 lesions in the arterial phase exhibited irregular ring enhancement. However, lesions in the portal and delayed phases (which were gradually filled with a contrast agent), presented a patchy or latticed enhancement. Twenty-two lesions in the arterial and delayed phases exhibited uneven mild/moderate patchy enhancements with a progressive and centripetal lesion. Five lesions emerged from the arterial phase without any significant enhancement and had only gradual enhancement during the delayed phase. The remaining 2 lesions had a decreased mild enhancement, presented comparatively high signals and the lesion center had visible small spotted low signals. The DWI signals displayed a slightly high or high unevenness. Some lesion peripheries had a high signal but lesion centers displayed a relatively low or slightly low signal and irregular patches. There were significant differences between the ADC values of the lesion edge, lesion center and liver parenchyma. The IMCC detection rates of the Gd-BOPTA-enhanced MRI and DWI were higher than those of the unenhanced MRI. Our study demonstrated that both the Gd-BOPTA-enhanced MRI and DWI had higher accuracies rates than an unenhanced MRI. Furthermore, the hepatobiliary phase of IMCC plays an important role in the diagnosis and identification of IMCC constituents.

Respiratory-motion artefacts in liver MRI following injection of gadoxetate disodium and gadobenate dimeglumine: an intra-individual comparative study in cirrhotic patients

To perform an intra-individual comparison of the frequency of respiratory-motion artefacts on magnetic resonance imaging (MRI) in cirrhotic patients following injection of gadoxetate disodium and gadobenate dimeglumine. Ninety-five cirrhotic patients (61 men and 34 women, mean age 58 years) underwent liver MRI with intravenous administration of gadoxetate disodium and gadobenate dimeglumine at different times (interval between studies, 189±83 days). Three readers scored the severity of respiratory-motion artefacts on the three-dimensional (3D) gradient-echo (GRE) images acquired before and after contrast medium injection. McNemar's test was used to assess the difference in frequency of new respiratory-motion artefacts and transient severe motion (TSM) artefacts between gadoxetate disodium and gadobenate dimeglumine MRI studies. The association between clinical and technical features and the occurrence of TSM on gadoxetate disodium MRI studies was investigated. On arterial phase images, new respiratory-motion artefacts were present in 32/95 (34%) cases after injection of gadoxetate disodium, while only seen in 2/95 (2%) cases after injection of gadobenate dimeglumine (p<0.0001). TSM was present in 6/95 (6%) cases after injection of gadoxetate disodium, and in 0/95 (0%) case after injection of gadobenate dimeglumine. No clinical or technical features were associated with the occurrence of TSM. In cirrhotic patients, respiratory-motion artefacts on arterial phase 3D GRE images are more frequently seen after injection of gadoxetate disodium than after injection of gadobenate dimeglumine.

Prospective Cohort Study of Nephrogenic Systemic Fibrosis in Patients With Stage 3-5 Chronic Kidney Disease Undergoing MRI With Injected Gadobenate Dimeglumine or Gadoteridol.

The purpose of this study was to determine the incidence of nephrogenic systemic fibrosis (NSF) in patients with chronic kidney disease (CKD) and moderate-to-severe impairment of kidney function who had not previously been exposed to gadolinium-based contrast agents (GBCAs) or referred to undergo contrast-enhanced MRI with gadobenate dimeglumine or gadoteridol. Two multicenter prospective cohort studies evaluated the incidence of unconfounded NSF in patients with stage 3 CKD (estimated glomerular filtration rate [eGFR] in cohort 1, 30-59 mL/min/1.73 m(2)) or stage 4 or 5 CKD (eGFR in cohort 2, < 30 mL/min/1.73 m(2)) after injection of gadobenate dimeglumine (study A) or gadoteridol (study B). A third study (study C) determined the incidence of NSF in patients with stage 4 or 5 CKD who had not received a GBCA in the 10 years before enrollment. Monitoring for signs and symptoms suggestive of NSF was performed via telephone at 1, 3, 6, and 18 months, with clinic visits occurring at 1 and 2 years. For studies A and B, the populations evaluated for NSF comprised 363 and 171 patients, respectively, with 318 and 159 patients in cohort 1 of each study, respectively, and with 45 and 12 patients in cohort 2, respectively. No signs or symptoms of NSF were reported or detected during the 2 years of patient monitoring. Likewise, no cases of NSF were reported for any of the 405 subjects enrolled in study C. To our knowledge, and consistent with reports in the literature, no association of gadobenate dimeglumine or gadoteridol with unconfounded cases of NSF has yet been established. Study data confirm that both gadoteridol and gadobenate dimeglumine properly belong to the class of GBCAs considered to be associated with the lowest risk of NSF.

Magnetic Resonance Lymphangiography for the Study of Lymphatic System in Lymphedema.

Imaging of the lymphatic system is difficult because of its structural and anatomical characteristics, and the conventional diagnostic method, radionuclide-based imaging, has the disadvantage of poor resolution. Magnetic resonance (MR) imaging has been shown the capability of depicting lymphatic channels in lymphedema recently. The purpose of this study was to evaluate the imaging of MR lymphangiography (MRL) in diagnosis of limb lymphedema and its possible role in the microsurgical management of lymphedema. A total of 710 patients with primary lymphedema (n = 378), secondary lymphedema (n = 332), were enrolled in the study. Contrast-enhanced lymphangiography was performed with 3.0 T MR unit (Philips Medical Systems, Best, The Netherlands) after intracutaneously injection of gadobenate dimeglumine. Kinetic of enhanced lymph flow within lymphatics and lymph nodes as well as the morphological abnormalities of lymphatic system were evaluated. MRL was able to display the detailed anatomical changes in the vessels and nodes. In primary lymphedema, there are three major types of lymphatic system malformation: (1) only lymph nodes affected, (2) only lymph vessels affected, and (3) both lymph vessels and lymph nodes affected. In secondary lymphedema MRL clearly demonstrated tortuous and dilated collecting lymphatics in lymphedemtous limbs. MRL also provided information concerning the functional status of lymph transport in lymphatic vessels and nodes by real-time visualization of enhanced lymph flow in lymphatic channels and within lymph nodes. Contrast MRL was capable of evaluating the anatomical and functional status of lymphatic vessels and lymph nodes in lymphedematous limb. This new imaging shows good potential for use in the diagnosis and surgical management of lymphedema.

MRI features of inflammatory hepatocellular adenomas on hepatocyte phase imaging with liver-specific contrast agents

To evaluate the presentation of inflammatory hepatocellular adenomas (HCAs) on hepatocyte phase MRI. We retrospectively reviewed the MRI features of histologically proven HCAs on hepatocyte phase imaging. Twenty-one lesions (17 with inflammatory subtype) were scanned with gadobenate dimeglumine. Signal intensities of the lesions were assessed in the hepatocyte phase and on the T1-weighted sequences before contrast. After gadobenate dimeglumine injection, 71% (12/17) of the inflammatory HCAs showed areas of iso- or hyperintensity to the surrounding liver in the hepatocyte phase. In 82% (10/12) of the iso- or hyperintense lesions, this was found over more than 75% of the lesion surface. None of the noninflammatory HCAs showed areas of iso- or hyperintensity to the surrounding liver in the hepatocyte phase. From these 12, 7 were hyperintense on T1-weighting before contrast due to liver steatosis, 2 due to intrinsic hyperintensity (on the in-phase sequence), and 3 were isointense. In contrast to noninflammatory HCAs, inflammatory HCAs can show areas of iso- to hyperintensity to the surrounding liver in the hepatocyte phase; therefore, other typical imaging features should also be used to distinguish between HCAs and FNHs.

Predictors of Dysplastic Nodule Diagnosis in Patients With Liver Cirrhosis on Unenhanced and Gadobenate Dimeglumine–Enhanced MRI With Dynamic and Hepatobiliary Phase

The purpose of this article is to assess whether unenhanced and gadobenate dimeglumine-enhanced MRI with dynamic and hepatobiliary phase may predict the diagnosis of dysplastic nodules in patients with liver cirrhosis. We retrospectively analyzed 75 cirrhotic patients (47 men and 28 women; mean [± SD] age, 55 ± 12 years) with 82 hepatocellular nodules, including histology-proven dysplastic nodules (n = 25; diameter, 1-3 cm) and hepatocellular carcinomas (n = 57; diameter, 2-3 cm) scanned by MRI before and after gadobenate dimeglumine injection during hepatic arterial phase (HAP), portal venous phase (PVP), equilibrium phase, and hepatobiliary phase. Nodule T1 and T2 intensities before contrast agent injection and nodule HAP, PVP, equilibrium phase, and hepatobiliary phase intensities were compared with the adjacent liver. Univariate and multivariate logistic regression analysis was conducted to assess how the nodule could predict dysplastic nodule diagnosis. Some imaging findings were independent predictors of dysplastic nodule diagnosis-namely, nodule T2 isohypointensity (odds ratio [OR], 12.28; 95% CI, 3.88-38.82), T1 isohyperintensity (OR, 26.74; 95% CI, 7.53-94.90), HAP isohypointensity (OR, 97.16; 95% CI, 20.06-470.49), PVP-equilibrium phase isohyperintensity (OR, 20.53; 95% CI, 5.36-78.62), and hepatobiliary phase isohyperintensity (OR, 119.6; 95% CI, 21.59-662.40). Nodule T2 and HAP isohypointensity (OR 31.47; 95% CI, 7.88-125.58), nodule T2 isohypointensity and hepatobiliary phase isohyperintensity (OR, 28.77; 95% CI, 7.79-106.19), nodule T1 isohyperintensity and HAP isohypointensity (OR, 17.22; 95% CI, 4.85-61.14), and nodule T1 and hepatobiliary phase isohyperintensity (OR, 19.39; 95% CI, 5.38-69.90) were also predictors of dysplastic nodule diagnosis. The combination of nodule appearance on T2-weighted MRI and nodule enhancement after gadobenate dimeglumine injection may predict dysplastic nodule diagnosis in patients with liver cirrhosis.

Safety and adverse effects during 24 hours after contrast-enhanced MRI with gadobenate dimeglumine (MultiHance®) in children

Gadolinium-based MR contrast agents have long been considered safe for routine diagnostic imaging. However, the advent of nephrogenic systemic fibrosis (NSF) among certain patients with severe renal insufficiency has brought the issue of safety into question. Nowhere is safety of greater concern than among children who frequently require multiple contrast-enhanced MRI examinations over an extended period of time. To retrospectively evaluate the safety of gadobenate dimeglumine for contrast-enhanced (CE) MRI across a range of indications. Two hundred pediatric inpatients (age: 4 days to 15 years) underwent CE MRI as part of clinical routine. The children received a gadobenate dimeglumine dose of either 0.05 mmol/kg body weight (liver, abdominal imaging, musculoskeletal imaging, brain and other rare indications) or 0.1 mmol/kg bodyweight (cardiovascular imaging, MR-urography). Young (< 8 years) children with congenital heart disease were intubated and underwent MRA evaluation with controlled ventilation. Monitoring for adverse events was performed for at least 24 h after each gadobenate dimeglumine injection. Depending on clinical necessity, laboratory measurements and, in some cases, vital sign and ECG determinations were made before and after contrast injection. Safety was evaluated by age group, indication and dose administered. No clinically adverse events were reported among children who had one MRI scan only or among children who had several examinations. There were no changes in creatinine or bilirubin levels even in very young children. No adverse events were recorded during the first 24 h following administration of gadobenate dimeglumine in 200 children.

Diagnosis of Inguinal Lymph Node Metastases Using Contrast Enhanced High Resolution MR Lymphangiography

Inguinal lymph nodes can be the first or the only clinical signs of tumor metastases. The aim of the study was to evaluate the role of contrast-enhanced high-resolution magnetic resonance (MR) lymphangiography in diagnosis of inguinal lymph node metastases. The study enrolled 26 patients with inguinal lymph node metastases. Contrast-enhanced lymphangiography was performed using a 3.0T MR unit after intracutaneous injection of gadobenate dimeglumine into the interdigital webs of the dorsal foot. Images of inguinal lymph nodes were acquired before and after contrast injection. All patients exhibited edema in the subcutaneous layer with significant dilatation of lymphatic collectors in the affected lower limbs on MR images. Before contrast injection, the outline and structure of the affected nodes were unclear on T2 weighted images. Structural changes became evident on postinjection T1-weighted images. Nodal involvement on contrast enhanced MR lymphangiograms was characterized as: 1) heterogeneous structure with partial or marginal enhancement of the node indicating partial occupation by tumor; 2) homogeneous structure of the node without contrast enhancement, indicating total occupation with metastasis, with increase or no change in size; and 3) heterogeneous structure with punctiform nodal enhancement indicating diffuse growth of tumor within the node. Further examinations confirmed the diagnoses of inguinal lymph node metastases of either regional or distal tumors. Contrast-enhanced high-resolution MR lymphangiography was a sensitive modality in the diagnosis of malignant peripheral lymphedema and the identification of inguinal lymph node metastasis in patients with various tumor origins.

Investigation of the Longitudinal Relaxation Rate of Blood After Gadobenate Dimeglumine Administration

To optimize the image acquisition parameters for improved steady-state (SS) contrast-enhanced magnetic resonance angiography (CE-MRA) of the carotid arteries with gadobenate dimeglumine. An inversion recovery fast low-angle shot (IR-FLASH) sequence for ultrafast determination of the longitudinal relaxation rate R1 was first optimized on phantoms and tested against a routine variable repetition time (TR) spin echo sequence used as reference standard. Different combinations of flip angle (FA, between 6 and 14 degrees) and inversion time (between 134 and 9000 milliseconds) were evaluated to achieve the best trade off between speed and accuracy. The optimized sequence was thereafter used in vivo in 5 subjects to determine the time evolution of blood R1 at 1.5 T after administration of gadobenate dimeglumine at 0.1 mmol/kg bodyweight. An optimal FA for angiographic measurement was thereafter derived from the Ernst equation based on experimental values of R1 previously determined in vivo. Finally, steady-state CE-MRA examinations were performed in 20 subjects to evaluate the improved contrast achieved after optimization of the FA for maximal blood signal enhancement. An ultrafast IR-FLASH sequence with a flip angle of 8 degrees and a properly defined set of inversion time values was shown to give in vitro R1 determinations that were in good agreement with those obtained using a routine, time consuming, variable-TR spin echo sequence. The use of this ultrafast IR-FLASH sequence in vivo allowed the blood signal behavior in the carotid arteries after gadobenate dimeglumine administration to be monitored. Using this sequence, the R1 decreased from 8.7±0.96 s⁻¹ at 30 seconds after injection to 3.8±0.24 s⁻¹ at 10 minutes after injection. Based on these data for R1, the optimal FA for SS CE-MRA was calculated to be 18 degrees for a gradient echo acquisition protocol with TR=7.5 milliseconds, when gadobenate dimeglumine is used. Significantly higher blood signal to noise ratio was achieved on SS images acquired using a three-dimensional spoiled gradient echo sequence with a FA of 18 degrees than on corresponding images acquired with a FA of 35 degrees as used typically for intravascular blood pool contrast agents (52.5±8.3 vs. 29.5±6.0; P<0.05, Mann-Whitney U test). Detailed experimental knowledge of the in vivo R1 behavior of blood after gadobenate dimeglumine injection and appropriate modification of the acquisition parameters enables improved signal intensity enhancement on steady-state CE-MRA of the carotid arteries.

Gadobenate dimeglumine‐enhanced liver MR imaging in cirrhotic patients: Quantitative and qualitative comparison of 1‐hour and 3‐hour delayed images

To compare the image quality and diagnostic performance of 1- and 3-h delayed-phase MR images (DPIs) after gadobenate dimeglumine injection in detecting small hepatocellular carcinomas (HCCs) in cirrhotic patients. Relative enhancement of the liver (RE(liver) ) and HCC (RE(HCC) ) and liver-to-lesion contrast-to-noise ratio (CNR) of HCC were measured quantitatively on 1- and 3-h DPIs in 65 patients with 88 HCCs. For qualitative analysis, two radiologists independently evaluated three image sets in 19 patients with 25 HCCs ≤ 2 cm and in 16 controls without HCCs: conventional liver MR without DPI (set A), adding 1-h DPI (set B), and adding 3-h DPI (set C), using a 5-point scale for diagnosing small HCCs. Diagnostic performance for small HCCs was analyzed using the alternative free-response receiver operating characteristic method. Mean RE(liver) (P = 0.013) and RE(HCC) (P < 0.001) were significantly higher on 1-h than on 3-h DPI, whereas CNR was significantly higher on 3-h than on 1-h DPI (P = 0.001). Observer-averaged figure of merit (FOM) was significantly higher for set C than for set A (0.942 versus 0.883; P = 0.013). In cirrhotic patients, 3-h DPI provides a higher liver-to-lesion contrast and a better diagnostic performance for small HCCs than 1-h DPI.

Enhancement of liver parenchyma after injection of hepatocyte‐specific MRI contrast media: A comparison of gadoxetic acid and gadobenate dimeglumine

To compare enhancement of liver parenchyma in MR imaging after injection of hepatocyte-specific contrast media. Patients (n = 295) with known/suspected focal liver lesions randomly received 0.025 mmol gadoxetic acid/kg body weight or 0.05 mmol gadobenate dimeglumine/kg body weight by means of bolus injection. MR imaging was performed before and immediately after injection, and in the delayed phase at approved time points (20 min after injection of gadoxetic acid and 40 min after injection of gadobenate dimeglumine). The relative liver enhancement for the overall population and a cirrhotic subgroup was compared in T1-weighted GRE sequences. An independent radiologist performed signal intensity measurements. Enhancement ratios were compared using confidence intervals (CIs). The relative liver enhancement in the overall population was superior with gadoxetic acid (57.24%) versus gadobenate dimeglumine (32.77%) in the delayed-imaging phase. The enhancement ratio between the contrast media was statistically significant at 1.75 (95% CI: 1.46-2.13). In the delayed phase, the enhancement of cirrhotic liver with gadoxetic acid (57.00%) was comparable to that in the overall population. Enhancement with gadobenate dimeglumine was inferior in cirrhotic liver parenchyma (26.85%). In the delayed, hepatocyte-specific phase, liver enhancement after injection of gadoxetic acid was superior to that obtained with gadobenate dimeglumine.

High-resolution MR lymphangiography to evaluate lymphatic function in experimental rabbit limb lymphedema

Objective To evaluate the feasibility of high-resolution MR lymphangiography with intracutaneous injection of gadodiamide, a commercially available, nonionic, extracellular paramagnetic con-trast agent,for the visualization of lymphatic vessels in lymphedema.Methods Post-surgical lymphedema was experimentally created in one hide limb of 6 rabbits.Another hide leg of each rabbit was used as the normal control.Four weeks later, normal and lymphedematous rabbit limbs were imaged following direct subcutaneous administration of gadobenate dimeglumine injection, 0.6 ml/limb.Images were obtained on axial and coronal planes with a Tl-weighted spin echo inversion-recovery sequence.Three days after above MR lymphangiography examination, LAS examination was applied as control.Results In the normal limb,collecting lymphatics and lymph node were clearly visualized as the Gd tracer was cleared from the intersti-tial compartnent rapidly.In contrast,the Gd tracer accumulated at the prior surgical site in the lymphed-ematous limb slowly.Quantitative assessment of Gd clearance demonstrated that accumulation of Gd was correlated with the impedance to lymph flow proximal to the site of surgical lymphatic ablation.Conclusion MR lymphangiography is a feasible and reliable method to be applied to quantitative functional imaging of the lymphatic vasculature in experimental models of lymphedema. Key words: Lymphedema ; Magnetic resonance ; Lymphangiography ; Function ;

Anatomic and functional evaluation of the lymphatics and lymph nodes in diagnosis of lymphatic circulation disorders with contrast magnetic resonance lymphangiography

Owing to its structural and anatomic characteristics, imaging of the lymphatic system has been difficult. The conventional diagnostic method of radionuclide-based imaging has the disadvantage of poor resolution. Recent work has shown that magnetic resonance imaging (MRI) can depict lymphatic channels in patients with lymphedema. This study evaluated the anatomic and functional images of contrast MR lymphangiography in the diagnosis of limb lymphatic circulation disorders. The study enrolled 27 patients with primary lymphedema. Four patients had bilateral disease, and 23 had unilateral disease. Contrast-enhanced lymphangiography was performed with a 3.0-T MR unit after the intracutaneous injection of gadobenate dimeglumine into the interdigital webs of the dorsal foot. The kinetics of enhanced lymph flow within the lymphatic system were calculated using the formula [speed in cm = total length of visualized lymph vessel in cm/inspection time in minutes] and by comparing dynamic nodal enhancement and time-signal intensity curves between edematous and contralateral limbs. Morphologic abnormalities of the lymphatic system were also evaluated. Examination of the MRIs after injection of the contrast agent showed enhanced lymphatic channels consistently visualized in all clinical lymphedematous limbs and in five contralateral limbs of unilateral lymphedema patients. The speed of flow within the lymphatics of lymphedematous limbs was 0.3 to 1.48 cm/min. Contrast enhancement in inguinal nodes of edematous limbs was significantly less than that of contralateral limbs (P < .01). Dynamic measurement of contrast enhancement showed a remarkable lowering of peak time (P < .01) and peak enhancement (P < .01), and a delay in outflow in inguinal nodes of affected limbs compared with that of control limbs. Postcontrast MRI also depicted varied distribution patterns of lymphatics and abnormal lymph flow pathways within lymph nodes in the limbs with lymphatic circulation disorders. Contrast MR lymphangiography with gadobenate dimeglumine is capable of visualizing the precise anatomy of lymphatic vessels and lymph nodes in lymphedematous limbs. It also provides information concerning the functional status of lymph flow transport in the lymphatic vessels and lymph nodes of these limbs.

Contrast-enhanced breast MR imaging of claustrophobic or oversized patients using an open low-field magnet

A number of women who should undergo magnetic resonance (MR) imaging of the breast cannot use this diagnostic tool due to claustrophobia or excessive body size for the restricted confines of standard closed MR systems. Our aim was to evaluate the performance of open low-field magnet breast MR imaging in such patients using a high-relaxivity contrast agent. Of 397 consecutive patients undergoing breast MR imaging, 379 (95.5%) were studied at 1.5 T. Due to claustrophobia (n=15) or large body size (n=3), 18 patients (4.5%) were studied on a 0.2-T open magnet using a body coil. A 3D dynamic T1-weighted gradient-echo 94-s sequence was acquired with intravenous injection of gadobenate dimeglumine (0.1 mmol/kg). The standard of reference was pathological examination for 16 lesions classified with a maximal Breast Imaging Reporting and Data System (BI-RADS) score from 3 to 5, fine-needle aspiration cytology and >or=2-year follow-up for two lesions classified as BI-RADS 3, and >or=2-years follow-up for five lesions classified as BI-RADS 2. Diagnostic MR image quality was achieved for 20/23 lesions in 15/18 patients. Three lesions (two invasive cancers and a cyst) were not assessed due to patient movement and considered as two false negatives and one false positive. Thus, an 86% sensitivity [13/15; 95% confidence interval (CI): 70%-100%], an 87% specificity (7/8; 95% CI: 65%-100%) and an 87% accuracy (20/23; 95% CI: 73%-100%) were obtained. The intraclass correlation coefficient between MR and pathologic lesion size was 0.845. In claustrophobic or oversized patients, open low-field breast MR with gadobenate dimeglumine yields good diagnostic performance.

The Value of Gadobenate Dimeglumine-Enhanced Delayed Phase MR Imaging for Characterization of Hepatocellular Nodules in the Cirrhotic Liver

To evaluate the value of 1-hour delayed phase imaging (DPI) of gadobenate dimeglumine (Gd-BOPTA)-enhanced MR imaging for the characterization of hepatocellular carcinoma (HCC) and dysplastic nodule (DN) in patients with cirrhosis. A total of 37 patients with 42 HCCs and 13 DNs were included in this study and all lesions were histopathologically confirmed except for 15 HCCs. T1-weighted 3-dimensional gradient-echo images were acquired before, immediately after (30, 60, 180 s), and 1 hour after bolus injection of gadobenate dimeglumine at a dose of 0.1 mmol/kg. The lesions were classified as isointense, hypointense, or hyperintense compared with the surrounding liver parenchyma on DPI for qualitative assessment. We performed quantitative analyses of the contrast-to-noise ratio (CNR) and of the relative contrast enhancement of the lesion on the DPI. In the qualitative analysis, among 42 HCCs, 30 (71.4%) were hypointense on DPI, and 10 (23.8%) and 2 (4.8%) were isointense and hyperintense, respectively; only 1 of 13 DNs (7.7%) was hypointense and 10 (76.9%) and 2 (15.4%) were isointense and hyperintense, respectively. In contrast, 25 HCCs (71.4%) of 35 hypervascular HCCs were hypointense on DPI, and no hypervascular DN (0/7) was hypointense with statistical significance (P = 0.0007). When we considered the hypointensity of the hepatic lesions on delayed phase as a sign of HCC in cirrhotic liver, our results gave a sensitivity of 71.4% and a specificity of 91.7%. In the quantitative analysis, the mean CNR of the HCCs and the DNs on the 1-hour DPI was -6.32 +/- 6.27 and -0.07 +/- 3.28, respectively; the difference between the HCCs and the DNs was significant (P < 0.05). Delayed gadobenate dimeglumine-enhanced MR imaging allows improved characterization of HCC in cirrhotic liver. The relative hypointensity to adjacent normal liver parenchyma is a reliable predictor that this lesion favors HCC rather than DN in cirrhotic liver.

Multinodular focal fatty infiltration of the liver: Atypical imaging findings on delayed T1‐weighted Gd‐BOPTA‐enhanced liver‐specific MR images

We report a case of pathologically confirmed multinodular focal fatty infiltration. MRI was performed after bolus injection of gadobenate dimeglumine (Gd-BOPTA, MultiHance; Bracco, Milan, Italy), a liver-specific paramagnetic, gadolinium (Gd)-based MR contrast agent that concomitantly enables the acquisition of a standard dynamic phase with timing strategies similar to those used for other extracellular fluid contrast agents, followed by a delayed T1-weighted liver-specific phase (the so-called hepatobiliary phase). In the present case, multiple rounded areas of fatty infiltration, although confidently diagnosed using chemical shift sequences due to a significant signal intensity reduction on out-of-phase images, were unexpectedly hypointense during the delayed liver-specific phase of Gd-BOPTA. Reduced Gd-BOPTA concentration during the liver-specific phase is generally correlated with liver malignancy. Since such lesions can be prospectively mistaken for metastatic disease, we performed a hepatic biopsy to establish a definitive diagnosis. Our empirical observations suggest that Gd-BOPTA uptake may be impaired in fatty infiltrated liver tissue. Because at present there is no report evaluating the kinetics of Gd-BOPTA in fatty liver, further studies are needed to specifically investigate this issue.

Clinical relevance of diffusion and perfusion magnetic resonance imaging in assessing intra-axial brain tumors

Advanced magnetic resonance (MR) imaging techniques provide physiologic information that complements the anatomic information available from conventional MR imaging. We evaluated the roles of diffusion and perfusion imaging for the assessment of grade and type of histologically proven intraaxial brain tumors. A total of 28 patients with intraaxial brain tumors underwent conventional MR imaging (T2- and T1-weighted sequences after gadobenate dimeglumine injection), diffusion imaging and T2*-weighted echo-planar perfusion imaging. Examinations were performed on 19 patients during initial diagnosis and on nine patients during follow-up therapy. Determinations of relative cerebral blood volume (rCBV) and apparent diffusion coefficient (ADC) were performed in the solid parts of each tumor, peritumoral region and contralateral white matter. For gliomas, rCBV values were greater in high-grade than in low-grade tumors (3.87+/-1.94 versus 1.30+/-0.42) at the time of initial diagnosis. rCBV values were increased in all recurrent tumors, except in one patient who presented with a combination of recurrent glioblastoma and massive radionecrosis on histology. Low-grade gliomas had low rCBV even in the presence of contrast medium enhancement. Differentiation between high- and low-grade gliomas was not possible using diffusion-weighted images and ADC values alone. In the peritumoral areas of untreated high-grade gliomas and metastases, the mean rCBV values were higher for high-grade gliomas (1.7+/-0.37) than for metastases (0.54+/-0.18) while the mean ADC values were higher for metastases. The rCBV values of four lymphomas were low and the signal intensity-time curves revealed a significant increase in signal intensity after the first pass of gadobenate dimeglumine. Diffusion and perfusion imaging, even with relatively short imaging and data processing times, provide important information for lesion characterization.