Injection Of Gd-BOPTA Research Articles

Hepatobiliary MR contrast agent uptake as a predictive biomarker of aggressive features on pathology and reduced recurrence-free survival in resectable hepatocellular carcinoma: comparison with dual-tracer 18F-FDG and 18F-FCH PET/CT

To compare the performance of the quantitative analysis of the hepatobiliary phase (HBP) tumor enhancement in gadobenate dimeglumine (Gd-BOPTA)-enhanced MRI and of dual-tracer 18F-FDG and 18F-fluorocholine (FCH) PET/CT for the prediction of tumor aggressiveness and recurrence-free survival (RFS) in resectable hepatocellular carcinoma (HCC). This retrospective, IRB approved study included 32 patients with 35 surgically proven HCCs. All patients underwent Gd-BOPTA-enhanced MRI including delayed HBP images, 18F-FDG PET/CT, and (for 29/32 patients) 18F-FCH PET/CT during the 2months prior to surgery. For each lesion, the lesion-to-liver contrast enhancement ratio (LLCER) on MRI HBP images and the SUVmax tumor-to-liver ratio (SUVT/L) for both tracers were calculated. Their predictive value for aggressive pathological features-including the histological grade and microvascular invasion (MVI)-and RFS were analyzed and compared using area under receiver operating characteristic (AUROC) curves and Cox regression models, respectively. The AUROCs for the identification of aggressive HCCs on pathology with LLCER, 18F-FDG SUVT/L, and 18F-FCH SUVT/L were 0.92 (95% CI 0.78, 0.98), 0.89 (95% CI 0.74, 0.97; p = 0.70), and 0.64 (95% CI 0.45, 0.80; p = 0.035). At multivariate Cox regression analysis, LLCER was identified as an independent predictor of RFS (HR (95% CI) = 0.91 (0.84, 0.99), p = 0.022). LLCER - 4.72% or less also accurately predicted moderate-poor differentiation grade (Se = 100%, Sp = 92.9%) and MVI (Se = 93.3%, Sp = 60%) and identified patients with poor RFS after surgical resection (p = 0.030). HBP tumor enhancement after Gd-BOPTA injection may help identify aggressive HCC pathological features, and patients with reduced recurrence-free survival after surgical resection. • In patients with resectable HCC, the quantitative analysis of the HBP tumor enhancement in Gd-BOPTA-enhanced MRI (LLCER) accurately identifies moderately-poorly differentiated and/or MVI-positive HCCs. • After surgical resection for HCC, patients with LLCER - 4.72% or less had significantly poorer recurrence-free survival than patients with LLCER superior to - 4.72%. • Gd-BOPTA-enhanced MRI with delayed HBP images may be suggested as part of pre-surgery workup in patients with resectable HCC.

Diagnostic value of gadobenate dimeglumine enhanced MRI in hepatic fibrosis of rats

Objective: To evaluate the value of Gd-BOPTA enhanced MRI in the staging of liver fibrosis. Method: Fifty male SD rats (6-week-old, 180-220 g) were divided into the modeling group (n=42) and the control group (n=8). The model of liver fibrosis in the modeling group was established by carbon tetrachloride (animal license No. SYXK (Su) 2017-0043). From week 2 to week 10, rats in the modeling group (n=4) and control group (n=1) were randomly selected to scan 1 h(RER1), 2 h(RER2) and 3 h(RER3) after injection of Gd-BOPTA, respectively, to measure the relative enhancement rate (RER) of liver parenchyma. The shape of intrahepatic bile duct and the degree of enhancement at each time point were observed. Results: Forty-two rats (34 rats in the modeling group and 8 rats in the control group) completed the experiment. RER1, RER2 and RER3 of the control group were 1.44±0.37, 1.22±0.37 and 0.84±0.28 respectively. RER1, RER2 and RER3 of the modeling group were respectively: S1 (n=6): 1.49±0.48, 1.29±0.39, 0.91±0.38;S2 (n=9): 1.48±0.44, 1.34±0.37, 1.04±0.40;S3 (n=11): 1.49±0.43, 1.37±0.39, 1.21±0.30; S4 (n=8): 1.49±0.44, 1.40±0.37, 1.24±0.40. There was no significant difference in RER1 and RER2 values between the control group and the liver fibrosis group (F=0.022, P=0.999; F=0.301, P=0.875). There were significant differences between the control group and RER3 values of hepatic fibrosis stage S3 and S4 (t=2.249, P=0.031; t=2.274, P=0.029), there was no significant difference between the remaining groups (all P>0.05).In the control group, the intrahepatic bile duct was obviously strengthened within 1 hour after enhancement, and walked naturally. The intrahepatic bile duct was slightly enhanced 1h after the enhancement of S3-S4 stage of hepatic fibrosis, and the intrahepatic bile duct was significantly enhanced 2-3 hours later, with distorted alignment. Conclusion: Delayed 3 hours liver parenchymal RER and intrahepatic bile duct distortion delay enhancement after Gd-BOPTA enhancement contribute to the S3-S4 diagnosis of liver fibrosis.

Iso- or hyperintensity of hepatocellular adenomas on hepatobiliary phase does not always correspond to hepatospecific contrast-agent uptake: importance for tumor subtyping.

This study was conducted in order to evaluate if iso- or hyperintensity of HCAs on HBP is systematically related to a high uptake of hepatospecific contrast agent, using a quantitative approach. This bicentric retrospective study included all patients with histologically confirmed and subtyped HCA from 2009 to 2017 who underwent MRI with HBP after Gd-BOPTA injection and who showed iso- or hyperintensity on HBP. The signal intensity of tumors on pre- and postcontrast images and the presence of hepatic steatosis were noted. Contrast uptake on HBP was quantified using the liver-to-lesion contrast enhancement ratio (LLCER) and compared between HCA subtypes (Wilcoxon signed-rank test). Categorical variables were compared using chi-square tests. Twenty-four HCAs showed iso- or hyperintensity on HBP, specifically 17 inflammatory (IHCAs) and 7 β-catenin HCAs (BHCAs). Eighteen HCAs (75%) (17 IHCAs and 1 BHCAs) had a LLCER < 0% (median - 13.6%, group 1), of which 94% were hyperintense on precontrast T1-W images, with background hepatic steatosis. Six HCAs (25%) had LLCER ≥ 0% (median 2.9%, group 2), and all were BHCAs. A LLCER ≥ 1.6% was associated with the diagnosis of BHCA with a sensitivity of 86% and a specificity of 100%. In conclusion, iso- or hyperintensity of hepatocellular adenomas on HBP does not necessarily correspond to an increased hepatospecific contrast-agent uptake. In IHCA, tumor hyperintensity on precontrast images and the underlying steatosis likely explain such iso- or hyperintensity, which do show reduced HBP contrast-agent uptake. On the other hand, marked contrast uptake can be observed, especially in BHCA. • Iso- or hyperintensity on HBP does not necessarily reflect a high uptake of hepatospecific contrast agent. • Discrepancies between qualitative signal intensity and quantitative hepatospecific contrast uptake can be explained in IHCA by a combination of tumor hyperintensity on precontrast images and underlying hepatic steatosis. • In BHCA, iso- or hyperintensity on HBP does actually correspond to a greater contrast uptake than that of the liver, demonstrated by an increased lesion-to-liver contrast enhancement ratio (LLCER).

Chimeric mouse model for MRI contrast agent evaluation.

While rodents are the primary animal models for contrast agent evaluation, rodents can potentially misrepresent human organ clearance of newly developed contrast agents. For example, gadolinium (Gd)-BOPTA has ~50% hepatic clearance in rodents, but ~5% in humans. This study demonstrates the benefit of chimeric mice expressing human hepatic OATPs (organic anion-transporting polypeptides) to improve evaluation of novel contrast agents for clinical use. FVB (wild-type) and OATP1B1/1B3 knock-in mice were injected with hepatospecific MRI contrast agents (Gd-EOB-DTPA, Gd-BOPTA) and nonspecific Gd-DTPA. T1 -weighted dynamic contrast-enhanced MRI was performed on mice injected intravenously. Hepatic MRI signal enhancement was calculated per time point. Mass of gadolinium cleared per time point and percentage elimination by means of feces and urine were also measured. Following intravenous injection of Gd-BOPTA in chimeric OATP1B1/1B3 knock-in mice, hepatic MRI signal enhancement and elimination by liver was more reflective of human hepatic clearance than that measured in wild-type mice. Gd-BOPTA hepatic MRI signal enhancement was reduced to 22% relative to wild-type mice. Gd-BOPTA elimination in wild-type mice was 83% fecal compared with 32% fecal in chimeric mice. Hepatic MRI signal enhancement and elimination for Gd-EOB-DTPA and Gd-DTPA were similar between wild-type and chimeric cohorts. Hepatic MRI signal enhancement and elimination of Gd-EOB-DTPA, Gd-BOPTA, and Gd-DTPA in chimeric OATP1B1/1B3 knock-in mice closely mimics that seen in humans. This study provides evidence that the chimeric knock-in mouse is a more useful screening tool for novel MRI contrast agents destined for clinical use as compared to the traditionally used wild-type models.

Peritoneal and pleural fluids may appear hyperintense on hepatobiliary phase using hepatobiliary MR contrast agents.

To describe the effect of hepatobiliary-specific MR imaging contrast agent (HBCA) administration on the signal intensity of peritoneal and pleural fluid effusions on T1-weighted MR images. From October 2015 to May 2016 139 patients (mean 60±10 years old, 69 % males) with peritoneal or pleural effusions without biliary leakage who underwent HBCA-MRI (Gd-BOPTA or Gd-EOB-DTPA) at 1.5T and 3T were included from two centres. The fluid signal intensity was classified as hypo/iso/hyperintense before/after HBCA administration. The relative signal enhancement (RE) was calculated. On hepatobiliary phase (HBP), peritoneal fluids appeared hyper/isointense in 88-100 % and pleural effusions in 100 % of the patients following Gd-BOPTA administration. All fluids remained hypointense following Gd-EOB-DTPA. The signal intensity of fluids increased with both HBCA but RE was significantly higher following Gd-BOPTA (p=0.002 to <0.001). RE was correlated with HBP acquisition time-point (r=0.42, p<0.001 and r=0.50, p=0.033 for peritoneal and pleural fluids). The signal intensity of pleural and peritoneal fluids progressively increases following HBCA administration in the absence of biliary leakage. Due to its later hepatobiliary phase, this is more pronounced after Gd-BOPTA injection, leading to fluid hyperintensity that is not observed after Gd-EOB-DTPA injection. • Fluids appear hyper/isointense on HBP in most patients after Gd-BOPTA injection. • Fluids remain hypointense on HBP after Gd-EOB-DTPA injection. • RE of fluids increases with time after liver-specific Gd injection. • RE of fluids is higher in patients with chronic liver disease.

Comparison of gadoxetic acid to gadobenate dimeglumine for assessment of biliary anatomy of potential liver donors.

To compare MRI using gadobenate dimeglumine (Gd-BOPTA) vs. gadoxetic acid disodium (Gd-EOB-DTPA) for the assessment of biliary anatomy of potential liver donors. 76 potential liver donors (39M/37F, mean 38years) who underwent 1.5T MRI using Gd-BOPTA (n=37) or Gd-EOB-DTPA (n=39) were retrospectively evaluated. T2 cholangiogram (T2 MRC) and delayed hepatobiliary phase (HBP) T1 cholangiogram (T1 MRC) (performed during HBP 20min after injection of Gd-EOB-DTPA and 1-2h after Gd-BOPTA injection) were obtained in addition to MR angiogram/venogram. Two independent observers evaluated image quality (IQ) and conspicuity scores (CS) of the biliary system. Biliary anatomy was assessed in 3 reading sessions (T2 MRC, T1 MRC, and combined T2/T1 MRC). Reference standard consisted of consensus reading of two separate observers of all image sets, clinical/surgical information and intraoperative cholangiogram when available. Datasets were compared using the Mann-Whitney U test or Chi-squared test. There was no difference in IQ for T1 MRC using either contrast agent or T2 MRC vs. T1 MRC for both observers (all p values >0.07). There was superior CS for T2 MRC vs. Gd-BOPTA T1 MRC for both observers and T2 MRC vs. Gd-EOB for one observer (p<0.001). No difference was found for biliary variant detection for T1 MRC (with either contrast agent) vs. T2 MRC. Combined T2/T1 MRC demonstrated improved sensitivity for biliary variant detection using Gd-BOPTA for both observers (p<0.004) and Gd-EOB-DTPA for one observer (p<0.001). Equivalent image quality was found for T1 MRC obtained with Gd-BOPTA or Gd-EOB-DTPA and T2 MRC. T1 MRC is equivalent to T2 MRC for detection of variant biliary anatomy, and the combination of sequences may have added value.

Immediate Adverse Reactions to Gadolinium-Based MR Contrast Media: A Retrospective Analysis on 10,608 Examinations.

Background and Purpose. Contrast media (CM) for magnetic resonance imaging (MRI) may determine the development of acute adverse reactions. Objective was to retrospectively assess the frequency and severity of adverse reactions associated with gadolinium-based contrast agents (GBCAs) injection in patients who underwent MRI. Material and Methods. At our center 10608 MRI examinations with CM were performed using five different GBCAs: Gd-BOPTA (MultiHance), Gd-DTPA (Magnevist), Gd-EOBDTPA (Primovist), Gd-DOTA (Dotarem), and Gd-BTDO3A (Gadovist). Results. 32 acute adverse reactions occurred, accounting for 0.3% of all administration. Twelve reactions were associated with Gd-DOTA injection (0.11%), 9 with Gd-BOPTA injection (0.08%), 6 with Gd-BTDO3A (0.056%), 3 with Gd-EOB-DTPA (0.028%), and 2 with Gd-DTPA (0.018%). Twenty-four reactions (75.0%) were mild, four (12.5%) moderate, and four (12.5%) severe. The most severe reactions were seen associated with use of Gd-BOPTA, with 3 severe reactions in 32 total reactions. Conclusion. Acute adverse reactions are generally rare with the overall adverse reaction rate of 0.3%. The most common adverse reactions were not severe, consisting in skin rash and hives.

MRI IN SPINAL BONE MARROW REPLACEMENT DISORDERS

Objectives. The paper aims are: to present and illustrate the MRI aspects of the normal and pathological bone marrow involving the spine, focusing on MR techniques and interpretation in a precise clinico-biological context of each patient. Material and methods. The cases included in this study were explored using a 1.5 MRI system in T1-weighted, T2 FSE, STIR, FSE T2 Fat Sat sequences, in sagittal and or coronal plane. Sections made in the axial plane in T2 wi, were centered at the level of the lesion(s). In case of primitive or secondary tumoral lesions we have performed T1-weighted SE sequences Fat Sat pre-/ and post-iv. injection of Gd-BOPTA in multiple planes. In particular cases, we have used T1-weighted sections with a TE in and /out of phase. Imaging features. Normally, the bone marrow shows intermediate signal both on T1-/,T2 -/, Stir- weighted images in comparison to paravertebral muscle. Pathological aspects include: diffuse and focal tumor infiltration (leukemia, lymphoma, multiple myeloma, metastasis), that must be differentiate from hyperplasia (reconversion) of the red marrow, bone marrow depletion, supportive tissue pathology (primary and secondary myelofibrosis, Gaucher disease). Conclusions. MRI is the only imaging method that allows the analysis of the bone marrow. Knowledge of normal signal in different MRI sequences in correlation with the age and the clinico-biological context of the patient is essential for a correct interpretation and detection of different types of diseases involving bone marrow of the spine. In patients with a diffuse T1 hyposignal of the spinal bone marrow the differential diagnosis includes three main entities: conversion, myeloproliferative lesions and pathology of the support structures.

Coronary artery angiography and myocardial viability imaging: a 3.0-T contrast-enhanced magnetic resonance coronary artery angiography with Gd-BOPTA

With improving MR sequence, phase-array coil and image quality, cardiac magnetic resonance imaging is becoming a promising method for a comprehensive non-invasive evaluation of coronary artery and myocardial viability. The study aimed to evaluate contrast-enhanced whole-heart coronary MR angiography (CE WH-CMRA) at 3.0-Tesla for the diagnosis of significant stenosis (≥50%) and detection of myocardial infarction (MI) in patients with suspected coronary artery disease (CAD). CE WH-CMRA was performed in consecutive 70 patients with suspected CAD by using a 3.0-T MR system. A respiratory-gated, electrocardiography-triggered, inversion-recovery, segmented fast low angle shot sequence (TI = 200 ms) was used. Data acquisition began 60 s after the slow injection of Gd-BOPTA (0.2 mmol/kg body weight, at an injection rate 0.3 ml/s). At last, breath-hold 2D-PSIR-SSFP sequence was performed. Diagnostic accuracy of CE WH-CMRA in detecting significant stenosis (≥50%) was evaluated using invasive coronary angiography as the referenced standard. The MI region appearing as high signal intensity visualized on CEWH-CMRA and 2D-PSIR-SSFP images were compared and analyzed. CE WH-CMRA correctly identified 42 of 44 patients with significant CAD. The overall sensitivity, specificity, negative predictive value, positive predictive value and accuracy for diagnosing significant CAD was 83.6, 95.8, 96.0, 82.8 and 93.4% respectively. The MI region detected by WH-CMRA and 2D-PSIR-SSFP were consistent in 10 patients and these segments manifested with transmural or subendocardial enhancement patterns. Only one MI patient was judged inconsistent between WH-CMRA and 2D-PSIR-SSFP, who was confirmed by clinical and electrocardiogram results. The enhancement pattern in this patient was spotted and focal in 2D-PSIR-SSFP, but was dismissed by WH-CMRA. It is feasible to obtain information about coronary artery stenosis and myocardial viability in a single CE WH-CMRA with administration of Gd-BOPTA.

Lesion detection and assessment of extrahepatic findings in abdominal MRI using hepatocyte specific contrast agents – comparison of Gd-EOB-DTPA and Gd-BOPTA

BackgroundTo evaluate the contrast agent performance of Gd-EOB-DTPA and Gd-BOPTA for detection and assessment of extrahepatic findings, semi-quantitatively and qualitatively.Methods13 patients with 19 extrahepatic lesions underwent liver MRI with Gd-EOB-DTPA and Gd-BOPTA. Quantitative and relative SNR measurements were performed in each dataset in the arterial and portalvenous phase within the extrahepatic lesion, aorta, inferior vena cava, portal vein, spleen, pancreas and renal cortex. Further, relative CNR measurements were performed. Three readers assessed contrast quality using a five-point scale and choosing the preferred image dataset. Statistical analysis consisted of a Student’s t-test with p < 0.05 deemed significant, a weighted kappa statistic for assessment of interobserver variability and an ROC analysis.ResultsMean SNR after injection of Gd-BOPTA was significantly higher compared with Gd-EOB-DTPA for all measurements (p < 0.05). Mean relative SNR was also higher for Gd-BOPTA, but without being statistically significant. There was no significant difference in relative CNR. Interobserver agreement for selection of image preference was moderate (mean weighted kappa 0.485). The area under the curve for the ROC-analysis regarding contrast agent performance was 0.464.ConclusionEven though mean SNR is significantly higher after injection of Gd-BOPTA compared with Gd-EOB-DTPA, there is no significant difference in relative CNR with extrahepatic lesions being assessed equally well. Visual impression may differ after injection of Gd-EOB-DTPA, but does not influence image interpretation. Extrahepatic findings can be assessed similarly to MRI after injection of Gd-BOPTA.

Advantages of gadobenate dimeglumine-enhanced MR cholangiography in the diagnosis of post-liver transplant bile leakage

To assess the value of magnetic resonance cholangiography with gadobenate dimeglumine (Gd-BOPTA) where there is a suspicion of bile leakage in the post-liver transplant patient. Eight patients who had undergone a liver transplant underwent 14 MR cholangiograms, five of whom presented bile leakage while the other three had no biliary system complications. The results were compared to conventional bile duct opacification (by endoscopy or t-tube cholangiogram). The analysis covered whether there was opacification of the common bile duct and intrahepatic bile ducts on T1-weighted sequences after an injection of Gd-BOPTA on delayed biliary excretion phase sequences that were carried out on average 74 min after the injection. Enhancing perihepatic collections were also taken into account. Opacification of the bile ducts on delayed-phase MR cholangiogram sequences was always seen in the absence of bile leakage, and was never found when leakage was present. Enhancing perihepatic collections pointed to bile leakage every time. Gd-BOPTA-enhanced MR cholangiography is a simple and non-invasive technique for detecting bile leakage in the post-liver transplant patient.

Arterial enhancing‐only nodules less than 2 cm in diameter in patients with liver cirrhosis: Predictors of hepatocellular carcinoma diagnosis on gadobenate dimeglumine‐enhanced mr imaging

To assess whether gadobenate dimeglumine (Gd-BOPTA)-enhanced MR imaging could predict hepatocellular carcinoma (HCC) diagnosis in small arterial enhancing-only nodules detected by contrast-enhanced computed tomography (CT) in patients with liver cirrhosis. We prospectively recruited 125 cirrhotic patients (67 males, and 58 females; age: 68 ± 12.36 years) with 151 small (<2 cm in diameter) arterial enhancing-only nodules identified by contrast-enhanced CT. All patients were scanned by MR imaging before and after Gd-BOPTA injection during the hepatic arterial phase (HAP), portal venous phase (PVP), equilibrium phase (EP), and hepatobiliary phase (HP). Nodule characterization was based on reference imaging criteria (n = 29 nodules), follow-up (n = 105), or histology (n = 17). Two radiologists (5 and 10 years experience) analyzed the MR images, and logistic regression was conducted to assess how well MR imaging findings could predict HCC diagnosis. Final diagnoses included 115 benign nodules and 36 HCCs. Nodule T2 hyperintensity, T1 hypointensity, PVP-EP hypointensity, and HP hypointensity were the best predictors of HCC on univariate analysis. Nodule T2 hyperintensity, T1 hypointensity, and HP hypointensity, were independent predictors of HCC on multivariate analysis. Gd-BOPTA-enhanced MR imaging provides imaging findings which may predict a diagnosis of HCC in small arterial enhancing-only nodules in cirrhotic patients.

Gadobenate Dimeglumine–Enhanced Liver Magnetic Resonance Imaging

The objective of the study was to determine the value of addition of hepatobiliary phase to dynamic gadobenate dimeglumine (Gd-BOPTA)-enhanced imaging for the detection of focal liver lesions (nodules with diameter ≤3.0 cm). Routine nonenhanced magnetic resonance images were obtained in 25 patients with focal liver lesions suggested by ultrasonography and/or computed tomography.T1-weighted dynamic gradient-echo images were acquired immediately and 100 minutes after bolus injection of Gd-BOPTA. The number of the lesions detected by T1-weighted imaging, T2-weighted imaging, diffusion-weighted imaging, dynamic contrast-enhanced, and delayed hepatobiliary-phase imaging was counted, respectively. Contrast-to-noise ratios were measured for all the sequences including delayed hepatobiliary-phase imaging. The signal intensity and morphologic features of liver parenchyma and lesions were recorded and analyzed. There were 7 patients with hepatocellular carcinomas, 6 with hemangiomas, 7 with metastases, and 5 with cholangiocarcinomas. The delayed hepatobiliary-phase imaging showed a homogeneous enhancement of liver parenchyma and distinctive enhancement features of focal liver lesions. The delayed hepatobiliary-phase imaging was better than diffusion-weighted imaging for the detection of focal liver lesions (P < 0.05). The addition of hepatobiliary-phase imaging to Gd-BOPTA-enhanced dynamic imaging increased the sensitivity and accuracy for the detection of focal hepatic lesions.

The effect of obesity on regadenoson-induced myocardial hyperemia: a quantitative magnetic resonance imaging study

The A2A receptor agonist, regadenoson, is increasingly used as a vasodilator during nuclear myocardial perfusion imaging. Regadenoson is administered as a single, fixed dose. Given the frequency of obesity in patients with symptoms of heart disease, it is important to know whether the fixed dose of regadenoson produces maximal coronary hyperemia in subjects of widely varying body size. Thirty subjects (12 female, 18 male, mean BMI 30.3 ± 6.5, range 19.6–46.6) were imaged on a 3T magnetic resonance scanner. Imaging with a saturation recovery radial turboFLASH sequence was done first at rest, then during adenosine infusion (140 μg/kg/min) and 30 min later with regadenoson (0.4 mg/5 ml bolus). A 5 cc/s injection of Gd-BOPTA was used for each perfusion sequence, with doses of 0.02, 0.03 and 0.03 mmol/kg, respectively. Analysis of the upslope of myocardial time-intensity curves and quantitative processing to obtain myocardial perfusion reserve (MPR) values were performed for each vasodilator. The tissue upslopes for adenosine and regadenoson matched closely (y = 1.1x + 0.03, r = 0.9). Mean MPR was 2.3 ± 0.6 for adenosine and 2.4 ± 0.9 for regadenoson (p = 0.14). There was good agreement between MPR measured with adenosine and regadenoson (y = 1.1x − 0.06, r = 0.7). The MPR values measured with both agents tended to be lower as BMI increased. There were no complications during administration of either agent. Regadenoson produced fewer side effects. Fixed dose regadenoson and weight adjusted adenosine produce similar measures of MPR in patients with a wide range of body sizes. Regadenoson is a potentially useful vasodilator for stress MRI studies.

A direct comparison of adenosine and regadenoson myocardial perfusion reserves measured by MRI

Methods 8 subjects (5 female, 3 male) without ischemia were imaged on a 3 T Siemens Trio system. Imaging was done first at rest, and then during adenosine infusion (140 ug/ kg/min) and 34 ± 4 minutes later with regadenoson injection (0.4 mg/5 ml). A 5 cc/sec injection of Gd-BOPTA (MultihanceTM) was used, with doses of 0.02, 0.03 and 0.03 mmol/kg, respectively. The contrast was injected ~3 minutes after the start of the adenosine infusion, and ~90 seconds after the regadenoson injection. A saturation recovery radial turboFLASH sequence was used with 72 rays acquired after each saturation pulse. Scan parameters were TR = 2.6 msec, TE = 1.14 msec, flip = 14, slice thickness = 8 mm. Reconstruction was performed by iteratively minimizing a cost function as in [1] with total variation constraints in both space and time dimensions. Processing was performed in a manner similar to [2] to convert the arterial input functions into gadolinium concentration to remove the effects of saturation. Images were registered and segmented to give time curves from 6 tissue regions per slice. The curves were fit to a two compartment model and Ktrans used as an index of perfusion.

Initial experience on utility of gadobenate dimeglumine (Gd‐BOPTA) enhanced T1‐weighted MR cholangiography in diagnosis of acute cholecystitis

To investigate the feasibility of the use of gadobenate dimeglumine (also known as Gd-BOPTA) -enhanced T1-weighted MR cholangiography in diagnosis of acute cholecystitis. This prospectively designed institutional review board-approved HIPAA-compliant study was done between January and November 2007. We included 11 consecutive patients (7 male, mean age 59 years) who presented to the emergency room with acute right upper quadrant pain and with equivocal physical examination and/or ultrasound findings. The control group included 15 patients who underwent liver MRI with Gd-BOPTA. All patients underwent contrast-enhanced (CE) MR cholangiography examinations. CE-MR cholangiography was performed on a 1.5 Tesla magnet using 3D T1-weighted high resolution isotrophic volume examination (THRIVE) obtained at the 90th min after intravenous injection of Gd-BOPTA. Imaging features detected on CE-MR cholangiography were correlated with operative and histopathologic findings. In the control group, GD-BOPTA was visualized within the gallbladder in all subjects. For the study group, gallstones were present in nine patients (n = 7 both in gallbladder and cystic duct, n = 1 only in gallbladder, n = 1 only in cystic duct) on MRCP. Hydropic gallbladder was detected in seven patients, significant wall thickening in seven patients, and pericholecystic free fluid in 6 patients. On delayed phase CE cholangiography, significant enhancement of gallbladder wall was seen in 10 patients, and contrast agent excretion into gallbladder was absent in all patients. Surgery was performed in 10 patients, and cholecystostomy was done in 1 patient. Surgery and histopathology findings were consistent with cholecystitis in all patients. In addition to anatomical assessment, Gd-BOPTA-enhanced MR cholangiography can provide functional evaluation similar to HIDA scintigraphy in diagnosing acute cholecystitis in patients with acute right upper quadrant pain and equivocal findings.

Lower extremities magnetic resonance angiography with blood pressure cuff compression: Quantitative dynamic analysis

To quantitatively evaluate changes induced by the application of a femoral blood-pressure cuff (BPC) on run-off magnetic resonance angiography (MRA), which is a method generally previously proposed to reduce venous contamination in the leg. This study was Health Insurance Portability and Accountability Act (HIPAA)- and Institutional Review Board (IRB)-compliant. We used time-resolved gradient-echo gadolinium (Gd)-enhanced MRA to measure BPC effects on arterial, venous, and soft-tissue enhancement. Seven healthy volunteers (six men) were studied with the BPC applied at the mid-femoral level unilaterally using a 1.5 T MR system after intravenous injection of Gd-BOPTA. Different statistical tools were used such as the Wilcoxon signed rank test and a cubic smoothing spline fit. We found that BPC application induces delayed venous filling (as previously described), but also induces significant decreases in arterial inflow, arterial enhancement, vascular-soft tissue contrast, and delayed peak enhancement (which have not been previously measured). The potential benefits from using a BPC for run-off MRA must be balanced against the potential pitfalls, elucidated by our findings.

Gadobenate dimeglumine as a contrast agent for MRI of the mouse liver

We investigated the characteristics and utility of gadobenate dimeglumine (Gd-BOPTA) for MRI of the mouse liver. Mice were imaged under isoflurane anesthesia using a T(1)-weighted, three-dimensional fast low-angle shot (3D FLASH) sequence before and after intravenous or subcutaneous injection of Gd-BOPTA, and the time course of the contrast effect was examined. The appropriate dose for subcutaneous injection was determined visually, and the inter- and intra-observer reproducibilities in liver volumetry were evaluated with and without contrast injection. When mice were imaged sequentially before and after Gd-BOPTA injection and isoflurane anesthesia was maintained throughout the experiment, a long-lasting contrast effect was noted in the liver. Subcutaneous injection caused delayed, but favorable, enhancement. Washout from the liver was definitely accelerated in conscious mice in comparison with anesthetized mice. Visual evaluation indicated that a dose of 0.1 mmol/kg was appropriate for clear delineation of the entire liver margin, and the application of Gd-BOPTA significantly improved the inter- and intra-observer reproducibilities of liver volumetry. In conclusion, the intravenous or subcutaneous injection of Gd-BOPTA has a favorable contrast effect for the mouse liver, resulting in clear visualization of the liver border and improved reproducibility of liver volumetry. The possible influence of anesthesia on the pharmacokinetics of a contrast agent should be considered in determining the optimal scan timing.

Time course of contrast enhancement patterns after Gd-BOPTA in correlation to myocardial infarction and viability: a feasibility study.

Our objective was to analyze contrast enhancement patterns (CEP) and their time course after myocardial infarction (MI) following injection of Gd-BOPTA in correlation with recovery of regional function. Seven patients with subacute MI (18 +/- nine days) were examined before, as well as three and six (n = six) months after, revascularization of the infarct-related artery. Regional wall motion abnormalities were assessed by cine-MRI, and repetitive images of one representative slice were acquired up to 45 minutes after 0.05 mmol/kg Gd-BOPTA using a T1-w TSE-sequence. Two patients showed mid-wall/subendocardial, one patient subendocardial enhancement of MI associated with mechanical improvement after revascularization. Three patients without improvement revealed a mid-wall hypoenhanced zone within the first five minutes after injection, which was unchanged at follow-up. One patient with partial functional improvement showed transmural enhancement and a mid-wall hypoenhanced zone in adjacent areas. With this feasibility study, we concluded that mid-wall and/or subendocardial enhancement after Gd-BOPTA was associated with viable myocardium, whereas detection of microvascular obstruction correlating with scar formation is suggested by mid-wall hypoenhancement within the first five minutes after injection.

939-82 Efficacy of Gadolinium-BOPTA in Magnetic Resonance Imaging to Assess Acute Myocardial Infarction in Man

To assess the efficacy of the newly developed contrast agent gadolinium (Gd) benzyloxy propionic tetraacetic-acid BOPTA to detect acute myocardial infarction in patients using magnetic resonance imaging (MRI), 24 patients (age 53.3 ± 8.3) were examined 9.3 ± 3.7 days after a first myocardial infarction. Short axis Tl weighted images were obtained at 3 slice levels, before, immediately after injection of Gd-BOPTA, and after 15 min, 30 min, 45 min. Patients were divided into 2 groups according to the dose of Gd-BOPTA (0.05 mmol/kg and 0.1 mmol/kg). Contrast to noise ratio, signal intensity enhancement of normal and infarcted myocardium and signal intensity of infarcted to signal intensity of normal myocardium (SI inf/norm) was quantified. Contrast to noise ratio was not affected by the type of dosage (0.05 mmol/kg, 5.75 ± 0.85 vs. 0.1 mmol/kg, 5.32 ± 0.69). Enhancement of normal and infarcted myocardium increased immediately after administration of 0.05 mmol/kg Gd-BOPTA and gradually decreased thereafter (p &lt; 0.002 for normal myocardium) (see Figure). After 0.1 mmol/kg Gd-BOPTA administration, myocardial enhancement increased rapidly but showed no decrease within 45 minutes after administration (see Figure). Mean SI inf/norm was significantly improved after Gd-BOPTA administration (p &lt; 0.0005 for either dosage), and 0.05 mmol/kg produced significantly higher SI inf/norm than 0.1 mmol/kg (1.42 ± 0.069 vs. 1.34 ± 0.055 respectively, p = 0.015). Gd BOPTA is a useful contrast agent to assess myocardial infarction. Optimal results are obtained with a dosage of 0.05 mmol/kg body weight Gd-BOPTA. Persistent enhancement of infarcted and normal myocardium suggests an affinity of Gd-BOPTA for myocytes, making it a promising tool in MR imaging of ischemic heart disease.