Mannose-coated gadolinium liposomes for improved magnetic resonance imaging in acute pancreatitis.

PubMed

Tian, Bing; Liu, Ri; Chen, Shiyue; Chen, Luguang; Liu, Fang; Jia, Guorong; Dong, Yinmei; Li, Jing; Chen, Huaiwen; Lu, Jianping

2017-01-01

Acute pancreatitis (AP) is an acute inflammatory condition of the pancreas. The symptoms, treatment, and prognosis of mild and severe AP are different, and severe AP is a potentially life-threatening disease with a high incidence of complications and high mortality rate. Thus, it is urgent to develop an effective approach to reliably discriminate between mild and severe AP. We have developed novel gadolinium-diethylenetriaminepentaacetic (Gd-DTPA)-loaded mannosylated liposomes (named thereafter M-Gd-NL) that preferably target macrophages in AP. The targeting ability of M-Gd-NL toward macrophages in AP and its ability to discriminate between mild and severe AP were evaluated. The liposomes were of desired particle size (~100 nm), Gd-DTPA encapsulation efficiency (~85%), and stability. M-Gd-NL and non-targeted Gd-DTPA-loaded liposomes (Gd-NL) exhibited increased relaxivity compared with Gd-DTPA. Compared with Gd-NL and Gd-DTPA, M-Gd-NL showed increased uptake in macrophages, resulting in increased T 1 imaging ability both in vitro (macrophage cell line) and in vivo (severe AP model). Importantly, M-Gd-NL had the ability to discriminate between mild and severe AP, as reflected by a significantly higher T 1 magnetic resonance imaging signal in severe AP than in mild AP. M-Gd-NL did not show severe organ toxicity in rats. Our data suggest that M-Gd-NL had enhanced magnetic resonance imaging ability by targeting macrophages in AP and good ability to discriminate between mild and severe AP. We believe that M-Gd-NL could shed new light on the diagnosis of AP in the near future.

Gadolinium-enhanced magnetic resonance angiography in renal artery stenosis: comparison with digital subtraction angiography.

PubMed

Law, Y M; Tay, K H; Gan, Y U; Cheah, F K; Tan, B S

2008-04-01

To evaluate the accuracy of gadolinium-enhanced magnetic resonance angiography in assessing renal artery stenosis compared to catheter digital subtraction angiography. Retrospective study. Singapore General Hospital. Records of patients who underwent magnetic resonance angiography as well as digital subtraction angiography for assessment of renal artery stenosis from January 2003 to December 2005 were reviewed. There were 27 patients (14 male, 13 female) with a mean age of 62 (range, 44-77) years. There were 10 patients with renal transplants; their native renal arteries were not evaluated. Each of the two experienced interventional and body magnetic resonance radiologists, who were blinded to the results, reviewed the digital subtraction angiography and magnetic resonance angiography images respectively. Digital subtraction angiography was used as the standard of reference. A total of 39 renal arteries from these 27 patients were evaluated. One of the arteries was previously stented and could not be assessed with magnetic resonance angiography due to severe artefacts. Of the remaining 38 renal arteries, two were graded as normal, seven as having mild stenosis (<50%), eight as having moderate stenosis (> or =50% but <75%), and 21 as having severe stenosis (> or =75%). Magnetic resonance angiography and digital subtraction angiography were concordant in 89% of the arteries; magnetic resonance angiography overestimated the degree of stenosis in 8% and underestimated it in 3% of them. In the evaluation of clinically significant renal artery stenosis (> or =50%) with magnetic resonance angiography, the overall sensitivity, specificity, positive predictive value, and negative predictive value were 97%, 67%, 90%, and 86% respectively. The sensitivity and specificity of magnetic resonance angiography in transplant renal artery stenosis was 100%. CONCLUSION. Our experience suggested that gadolinium-enhanced magnetic resonance angiography is a sensitive non

Volume change and liver parenchymal signal intensity in Gd-EOB-DTPA-enhanced magnetic resonance imaging after portal vein embolization prior to hepatectomy.

PubMed

Akiba, Ayako; Murata, Satoru; Mine, Takahiko; Onozawa, Shiro; Sekine, Tetsuro; Amano, Yasuo; Kawano, Youichi; Uchida, Eiji; Kumita, Shin-ichiro

2014-01-01

To investigate the liver volume change and the potential of early evaluation by contrast-enhanced magnetic resonance imaging (MRI) using gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) after portal vein embolization (PVE). Retrospective evaluations of computed tomography (CT) volumetry of total liver and nonembolized areas were performed before and 3 weeks after PVE in 37 cases. The percentage of future liver remnant (%FLR) and the change ratio of %FLR (%FLR ratio) were calculated. Prospective evaluation of signal intensities (SIs) was performed to estimate the role of Gd-EOB-DTPA-enhanced MRI as a predictor of hypertrophy in 16 cases. The SI contrast between embolized and nonembolized areas was calculated 1 week after PVE. The change in SI contrast before and after PVE (SI ratio) was also calculated in 11 cases. %FLR ratio significantly increased, and SI ratio significantly decreased (both P < 0.01). There were significant negative correlations between %FLR and SI contrast and between %FLR and SI ratio (both P < 0.01). Hypertrophy in the nonembolized area after PVE was indicated by CT volumetry, and measurement of SI contrast and SI ratio in Gd-EOB-DTPA-enhanced MRI early after PVE may be useful to predict the potential for hepatic hypertrophy.

Presence of non-hypervascular hypointense nodules on Gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging in patients with hepatocellular carcinoma.

PubMed

Inoue, Masanori; Ogasawara, Sadahisa; Chiba, Tetsuhiro; Ooka, Yoshihiko; Wakamatsu, Toru; Kobayashi, Kazufumi; Suzuki, Eiichiro; Tawada, Akinobu; Yokosuka, Osamu

2017-04-01

Gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) performed before curative therapy for hepatocellular carcinoma (HCC) can distinguish between intrahepatic distant recurrence and hypervascularization. This study aimed to retrospectively evaluate the presence of non-hypervascular hypointense nodules on hepatobiliary phase images from Gd-EOB-DTPA-enhanced MRI as a risk factor of the intrahepatic distant recurrence of early stage HCC following radiofrequency ablation (RFA). A total of 132 patients who underwent preprocedural Gd-EOB-DTPA-enhanced MRI followed by initial RFA were retrospectively analyzed. Post-RFA intrahepatic distant recurrence, which excluded the hypervascularization of non-hypervascular hypointense nodules detected by preprocedural Gd-EOB-DTPA-enhanced MRI, was evaluated according to the presence of non-hypervascular hypointense nodules on preprocedural Gd-EOB-DTPA-enhanced MRI. Intrahepatic distant recurrence rates following RFA were higher in patients with non-hypervascular hypointense nodules (1-year: 22.5%, 2-year: 52.1%, 5-year: 89.1%) compared with in patients without non-hypervascular hypointense nodules (1-year: 7.0%, 2-year: 28.8%, 5-year: 48.7%). The presence of non-hypervascular hypointense nodules was associated with markedly increased cumulative recurrence rates of both identical and different subsegment intrahepatic distant recurrence, being an independent risk factor for post-RFA identical and different subsegment intrahepatic distant recurrence (identical: HR = 2.365, P = 0.027; different: HR = 3.276, P < 0.001). The presence of non-hypervascular hypointense nodules on hepatobiliary phase images from Gd-EOB-DTPA-enhanced MRI obtained prior to RFA is an important predictive factor of intrahepatic distant recurrence following RFA of HCC. © 2016 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.

Effect of intravenous gadolinium-DTPA on diffusion-weighted imaging for prostate lesions and normal tissue at 3.0-Tesla magnetic resonance imaging.

PubMed

Liu, Xiaohang; Zhou, Liangping; Peng, Weijun; Qian, Min

2011-06-01

Post-contrast diffusion-weighted imaging (DWI) is occasionally necessary when the results of the pre-contrast DWI differ from that of the dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), however, the effects of contrast material on DWI image and apparent diffusion coefficient (ADC) values have not been fully examined. To assess whether the administration of gadolinium-DTPA (Gd-DTPA) significantly affects the DWI of prostate lesions or normal tissue at the 3.0 Tesla magnetic resonance imaging (3.0 T MRI). Fifty-one patients with 52 prostate lesions, including 32 prostate cancer (25 in the peripheral zone [PZ] and seven that could not be confidently located) and 20 benign lesions (11 in PZ and nine in central grand [CG]), underwent echo-planar imaging (EPI)-DWI with b values of 0, 1000 s/mm(2) before and after administration of Gd-DTPA at 3.0 T MRI. Regions of interest (ROI) were drawn in all lesions, 42 normal PZ, 44 CG tissue and air to calculate the signal-to-noise ratio (SNR) and ADC values of lesions and normal tissue, and contrast-to-noise ratio (CNR) of lesions for pre- and post-contrast images. Statistical differences between pre- and post-contrast data were assessed by use of a paired t test. No significant differences between pre- and post-contrast images were found in the CNR of lesions and SNR of all the tissue except CG, which showed a statistically significant decline (9.6%, p < 0.0001) in SNR after contrast relative to the pre-contrast images. The post-contrast ADC values were statistically significantly lower than pre-contrast for prostate cancer (0.80 ± 0.11 mm(2)/s Vs 0.89 ± 0.12 mm(2)/s, p < 0.0001) and benign lesions (1.14 ± 0.30 mm(2)/s vs. 1.2 ± 0.29 mm(2)/s, p < 0.0001). No significant differences were detected for normal tissue. The administration of Gd-DTPA can slightly affect the DWI image quality of the prostate and reduce the ADC value of lesions at 3.0T MRI. Applications of post-contrast DWI require caution in

Myocardial late gadolinium enhancement in specific cardiomyopathies by cardiovascular magnetic resonance: a preliminary experience.

PubMed

Silva, Caterina; Moon, James C; Elkington, Andrew G; John, Anna S; Mohiaddin, Raad H; Pennell, Dudley J

2007-12-01

Late gadolinium enhancement cardiovascular magnetic resonance (CMR) can visualize myocardial interstitial abnormalities. The aim of this study was to assess whether regions of abnormal myocardium can also be visualized by late enhancement gadolinium CMR in the specific cardiomyopathies. A retrospective review of all referrals for gadolinium CMR with specific cardiomyopathy over 20 months. Nine patients with different specific cardiomyopathies were identified. Late enhancement was demonstrated in all patients, with a mean signal intensity of 390 +/- 220% compared with normal regions. The distribution pattern of late enhancement was unlike the subendocardial late enhancement related to coronary territories found in myocardial infarction. The affected areas included papillary muscles (sarcoid), the mid-myocardium (Anderson-Fabry disease, glycogen storage disease, myocarditis, Becker muscular dystrophy) and the global sub-endocardium (systemic sclerosis, Loeffler's endocarditis, amyloid, Churg-Strauss). Focal myocardial late gadolinium enhancement is found in the specific cardiomyopathies, and the pattern is distinct from that seen in infarction. Further systematic studies are warranted to assess whether the pattern and extent of late enhancement may aid diagnosis and prognostic assessment.

Renal damages after extracorporeal shock wave lithotripsy evaluated by Gd-DTPA-enhanced dynamic magnetic resonance imaging.

PubMed

Umekawa, T; Kohri, K; Yamate, T; Amasaki, N; Ishikawa, Y; Takada, M; Iguchi, M; Kurita, T

1992-01-01

Renal damages after extracorporeal shock wave lithotripsy (ESWL) were evaluated by magnetic resonance imaging (MRI) including Gd-DTPA-enhanced dynamic MRI in 37 patients with renal stone by spin echo methods (T1 and T2-weighted scan) and small tip angle gradient echo method (T2-weighted scan). Sixty-eight percent of the patients had changes in the MRI findings after ESWL. The frequently observed findings were perirenal fluid collection (38%), loss of corticomedullary junction (35%), and increased signal intensity of muscle and other adjacent tissue (34%). Preoperative Gd-DTPA-enhanced dynamic MRI showed low intensity band which suggests Gd-DTPA secretion from the glomerulus into the renal tubulus. In all cases the low intensity band became unclear after ESWL because of renal contusion due to ESWL. MRI, including Gd-DTPA-enhanced dynamic MRI, is considered to be a good procedure for evaluation of renal damages due to ESWL.

Simple method for quantification of gadolinium magnetic resonance imaging contrast agents using ESR spectroscopy.

PubMed

Takeshita, Keizo; Kinoshita, Shota; Okazaki, Shoko

2012-01-01

To develop an estimation method of gadolinium magnetic resonance imaging (MRI) contrast agents, the effect of concentration of Gd compounds on the ESR spectrum of nitroxyl radical was examined. A solution of either 4-oxo-2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPONE) or 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPOL) was mixed with a solution of Gd compound and the ESR spectrum was recorded. Increased concentration of gadolinium-diethylenetriamine pentaacetic acid chelate (Gd-DTPA), an MRI contrast agent, increased the peak-to-peak line widths of ESR spectra of the nitroxyl radicals, in accordance with a decrease of their signal heights. A linear relationship was observed between concentration of Gd-DTPA and line width of ESR signal, up to approximately 50 mmol/L Gd-DTPA, with a high correlation coefficient. Response of TEMPONE was 1.4-times higher than that of TEMPOL as evaluated from the slopes of the lines. The response was slightly different among Gd compounds; the slopes of calibration curves for acua[N,N-bis[2-[(carboxymethyl)[(methylcarbamoyl)methyl]amino]ethyl]glycinato(3-)]gadolinium hydrate (Gd-DTPA-BMA) (6.22 μT·L/mmol) and gadolinium-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid chelate (Gd-DOTA) (6.62 μT·L/mmol) were steeper than the slope for Gd-DTPA (5.45 μT·L/mmol), whereas the slope for gadolinium chloride (4.94 μT·L/mmol) was less steep than that for Gd-DTPA. This method is simple to apply. The results indicate that this method is useful for rough estimation of the concentration of Gd contrast agents if calibration is carried out with each standard compound. It was also found that the plot of the reciprocal square root of signal height against concentrations of contrast agents could be useful for the estimation if a constant volume of sample solution is taken and measured at the same position in the ESR cavity every time.

Metabolomic Analysis of N-acetylcysteine Protection of Injury from Gadolinium-DTPA Contrast Agent in Rats with Chronic Renal Failure.

PubMed

Wan, Chuanling; Xue, Rong; Zhan, Youyang; Wu, Yijie; Li, Xiaojing; Pei, Fengkui

2017-09-01

Gadolinium-based contrast agents (GBCAs) are frequently used to enhance the diagnostic efficacy of magnetic resonance imaging. On the other hand, the association between GBCA administration in patients with advanced renal disease and nephrogenic systemic fibrosis (NSF) was also noted. NSF is a systemic disorder characterized by widespread tissue fibrosis that may lead to death. N-acetylcysteine (NAC) protects rats from injury induced by gadolinium-based contrast agents, but the underlying mechanisms remain unclear. In this study, a nuclear magnetic resonance-based metabolomic approach was used to systematically investigate the protective effects of NAC on Gd-DTPA-induced injury. Thirty-two male Sprague-Dawley rats were given adenine (200 mg·kg -1 body weight) by oral gavage once a day for 3 weeks to induce chronic renal failure (CRF). NAC (600 mg/L in drinking water for 9 days) pretreatment was initiated 2 days before Gd-DTPA injection (a single tail vein injection, 2 mmol/kg body weight). Serum and liver samples were collected on day 7 after Gd-DTPA injection. By study design, the serum and hepatic metabolic changes of rats were measured in four groups of eight each: CRF, CRF-Gd, CRF-Gd-NAC, and CRF-NAC. Gd-DTPA administration to rats with CRF resulted in disturbances of several metabolic pathways, including glucose, lipid, glutamate, choline, gut microbiota, one-carbon, and purine metabolism. NAC pretreatment reversed the abundance changes of high-density lipoprotein, low-density lipoprotein, very low-density lipoprotein, glutamate, glutamine, oxidized glutathione, choline, phosphocholine, glycerophosphocholine, trimethylamine, and trimethylamine-N-oxide induced by Gd-DTPA. It is noteworthy, however, that the ameliorating effects of NAC on the disturbance of glutamate, choline, and gut microbiota metabolism may be specific to Gd-DTPA. In all, these findings could be potentially useful to decipher the underlying mechanisms of NAC protective effects from the

Neurosarcoidosis--demonstration of meningeal disease by gadolinium enhanced magnetic resonance imaging.

PubMed Central

Khaw, K T; Manji, H; Britton, J; Schon, F

1991-01-01

Arriving at a firm diagnosis of neurosarcoidosis continues to pose serious problems, particularly when evidence of granulomatous disease outside the nervous system is lacking. The commonest mode of presentation of neurosarcoidosis is with cranial nerve palsies. Two cases of presumed neurosarcoidosis with cranial nerve palsies showed clear evidence of focal meningeal disease on gadolinium-DTPA enhanced MRI brain scans. Although not specific for sarcoidosis, this technique may be very useful in aiding the diagnosis in suspected cases. Images PMID:1880510

Enhancements in hepatobiliary imaging: the spectrum of gadolinium-ethoxybenzyl diethylenetriaminepentaacetic acid usages in hepatobiliary magnetic resonance imaging.

PubMed

Channual, Stephanie; Pahwa, Anokh; Lu, David S; Raman, Steven S

2016-09-01

Gadolinium-ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) is a unique hepatocyte-specific contrast agent approved for clinical use in the United States in 2008. Gd-EOB-DTPA-enhanced MR has shown to improve detection and characterization of hepatic lesions. Gd-EOB-DTPA is now being routinely used in daily clinical practice worldwide. Therefore, it is important for radiologists to be familiar with the potential uses and pitfalls of Gd-EOB-DTPA, which extends beyond the assessment of focal hepatic lesions. The purpose of this article is to review the various usages of Gd-EOB-DTPA in hepatobiliary MR imaging.

The Effect of Pressure and Temperature on Separation of Free Gadolinium(III) From Gd-DTPA Complex by Nanofiltration-Complexation Method

NASA Astrophysics Data System (ADS)

Rahayu, Iman; Anggraeni, Anni; Ukun, MSS; Bahti, Husein H.

2017-05-01

Nowdays, the utilization of rare earth elements has been carried out widely in industry and medicine, one of them is gadolinium in Gd-DTPA complex is used as a contrast agent in a magnetic resonance imaging (MRI) diagnostic to increase the visual contrast between normal tissue and diseased. Although the stability of a given complex may be high enough, the complexation step couldnot have been completed, so there is possible to gadolinium(III) in the complex compound. Therefore, the function of that compounds should be dangerous because of the toxicity of gadolinium(III) in human body. So, it is necessarry to separate free gadolinium(III) from Gd-DTPA complex by nanofiltration-complexation. The method of this study is complexing of Gd2O3 with DTPA ligand by reflux and separation of Gd-DTPA complex from gadolinium(III) with a nanofiltration membrane on the variation of pressures(2, 3, 4, 5, 6 bars) and temperature (25, 30, 35, 40 °C) and determined the flux and rejection. The results of this study are the higher of pressures and temperatures, permeation flux are increasing and ion rejections are decreasing and gave the free gadolinium(III) rejection until 86.26%.

Diagnostic accuracy for macroscopic classification of nodular hepatocellular carcinoma: comparison of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging and angiography-assisted computed tomography.

PubMed

Tada, Toshifumi; Kumada, Takashi; Toyoda, Hidenori; Ito, Takanori; Sone, Yasuhiro; Okuda, Seiji; Ogawa, Sadanobu; Igura, Takumi; Imai, Yasuharu

2015-01-01

The macroscopic type of hepatocellular carcinoma (HCC) is a predictor of prognosis. We clarified the diagnostic value of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) in the macroscopic classification of nodular hepatocellular carcinoma (HCC) as compared to angiography-assisted computed tomography (CT). A total of 71 surgically resected nodular HCCs with a maximum diameter of ≤5 cm were investigated. HCCs were evaluated preoperatively using Gd-EOB-DTPA-enhanced MRI and angiography-assisted CT. HCCs were pathologically classified as simple nodular (SN), SN with extranodular growth (SN-EG), or confluent multinodular (CMN). SN-EG and CMN were grouped as non-SN. Five readers independently reviewed the images using a five-point scale. We examined the accuracy of both imaging modalities in differentiating between SN and non-SN HCC. Overall, the area under the receiver operating characteristic curve (A z ) for the diagnosis of non-SN did not differ between Gd-EOB-DTPA-enhanced MRI and angiography-assisted CT [0.879 (95% confidence interval (CI), 0.779-0.937) and 0.845 (95% CI, 0.723-0.919), respectively]. For HCCs >2 cm, the A z for Gd-EOB-DTPA-enhanced MRI was greater than 0.9. The sensitivity, specificity, and accuracy of Gd-EOB-DTPA-enhanced MRI for identifying non-SN were equal to or higher than values with angiography-assisted CT in all three categories (all tumors, ≤2 cm, and >2 cm), but the differences were not statistically significant. Using Gd-EOB-DTPA-enhanced MRI to assess the macroscopic findings in nodular HCC was equal or superior to using angiography-assisted CT.

Gd-DTPA T1 relaxivity in brain tissue obtained by convection-enhanced delivery, magnetic resonance imaging and emission spectroscopy

NASA Astrophysics Data System (ADS)

Haar, Peter J.; Broaddus, William C.; Chen, Zhi-jian; Fatouros, Panos P.; Gillies, George T.; Corwin, Frank D.

2010-06-01

A common approach to quantify gadolinium (Gd) contrast agents involves measuring the post-contrast change in T1 rate and then using the constant T1 relaxivity R to determine the contrast agent concentration. Because this method is fast and non-invasive, it could be potentially valuable in many areas of brain research. However, to accurately measure contrast agent concentrations in the brain, the T1 relaxivity R of the specific agent must be accurately known. Furthermore, the macromolecular content and compartmentalization of the brain extracellular space (ECS) are expected to significantly alter R from values measured in aqueous solutions. In this study, the T1 relaxivity R of gadolinium-diethylene-triamine penta-acetic acid (Gd-DTPA) was measured following direct interstitial infusions of three different contrast agent concentrations to the parenchyma of rat brains. Changes in magnetic resonance (MR) T1 values were compared to brain slice concentrations determined with inductively coupled plasma atomic emission spectroscopy (ICP-AES) to determine R in 15 rats. Additionally, samples of cerebrospinal fluid, blood and urine were analyzed to evaluate possible Gd-DTPA clearance from the brain. The T1 relaxivity R of Gd-DTPA in the brain ECS was measured to be 5.35 (mM s)-1 in a 2.4 T field. This value is considerably higher than estimations used in studies by other groups. Measurements of brain Gd-DTPA tissue concentrations using MRI and ICP-AES demonstrated a high degree of coincidence. Clearance of Gd-DTPA was minimal at the time point immediately after infusion. These results suggest that the environment of the brain does in fact significantly affect Gd T1 relaxivity, and that MRI can accurately measure contrast agent concentrations when this relaxivity is well characterized.

Acceleration of natural-abundance solid-state MAS NMR measurements on bone by paramagnetic relaxation from gadolinium-DTPA

NASA Astrophysics Data System (ADS)

Mroue, Kamal H.; Zhang, Rongchun; Zhu, Peizhi; McNerny, Erin; Kohn, David H.; Morris, Michael D.; Ramamoorthy, Ayyalusamy

2014-07-01

Reducing the data collection time without affecting the signal intensity and spectral resolution is one of the major challenges for the widespread application of multidimensional nuclear magnetic resonance (NMR) spectroscopy, especially in experiments conducted on complex heterogeneous biological systems such as bone. In most of these experiments, the NMR data collection time is ultimately governed by the proton spin-lattice relaxation times (T1). For over two decades, gadolinium(III)-DTPA (Gd-DTPA, DTPA = Diethylene triamine pentaacetic acid) has been one of the most widely used contrast-enhancement agents in magnetic resonance imaging (MRI). In this study, we demonstrate that Gd-DTPA can also be effectively used to enhance the longitudinal relaxation rates of protons in solid-state NMR experiments conducted on bone without significant line-broadening and chemical-shift-perturbation side effects. Using bovine cortical bone samples incubated in different concentrations of Gd-DTPA complex, the 1H T1 values were calculated from data collected by 1H spin-inversion recovery method detected in natural-abundance 13C cross-polarization magic angle spinning (CPMAS) NMR experiments. Our results reveal that the 1H T1 values can be successfully reduced by a factor of 3.5 using as low as 10 mM Gd-DTPA without reducing the spectral resolution and thus enabling faster data acquisition of the 13C CPMAS spectra. These results obtained from 13C-detected CPMAS experiments were further confirmed using 1H-detected ultrafast MAS experiments on Gd-DTPA doped bone samples. This approach considerably improves the signal-to-noise ratio per unit time of NMR experiments applied to bone samples by reducing the experimental time required to acquire the same number of scans.

Acceleration of natural-abundance solid-state MAS NMR measurements on bone by paramagnetic relaxation from gadolinium-DTPA.

PubMed

Mroue, Kamal H; Zhang, Rongchun; Zhu, Peizhi; McNerny, Erin; Kohn, David H; Morris, Michael D; Ramamoorthy, Ayyalusamy

2014-07-01

Reducing the data collection time without affecting the signal intensity and spectral resolution is one of the major challenges for the widespread application of multidimensional nuclear magnetic resonance (NMR) spectroscopy, especially in experiments conducted on complex heterogeneous biological systems such as bone. In most of these experiments, the NMR data collection time is ultimately governed by the proton spin-lattice relaxation times (T1). For over two decades, gadolinium(III)-DTPA (Gd-DTPA, DTPA=Diethylene triamine pentaacetic acid) has been one of the most widely used contrast-enhancement agents in magnetic resonance imaging (MRI). In this study, we demonstrate that Gd-DTPA can also be effectively used to enhance the longitudinal relaxation rates of protons in solid-state NMR experiments conducted on bone without significant line-broadening and chemical-shift-perturbation side effects. Using bovine cortical bone samples incubated in different concentrations of Gd-DTPA complex, the (1)H T1 values were calculated from data collected by (1)H spin-inversion recovery method detected in natural-abundance (13)C cross-polarization magic angle spinning (CPMAS) NMR experiments. Our results reveal that the (1)H T1 values can be successfully reduced by a factor of 3.5 using as low as 10mM Gd-DTPA without reducing the spectral resolution and thus enabling faster data acquisition of the (13)C CPMAS spectra. These results obtained from (13)C-detected CPMAS experiments were further confirmed using (1)H-detected ultrafast MAS experiments on Gd-DTPA doped bone samples. This approach considerably improves the signal-to-noise ratio per unit time of NMR experiments applied to bone samples by reducing the experimental time required to acquire the same number of scans. Copyright © 2014 Elsevier Inc. All rights reserved.

Nanoamplifiers synthesized from gadolinium and gold nanocomposites for magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Tian, Xiumei; Shao, Yuanzhi; He, Haoqiang; Liu, Huan; Shen, Yingying; Huang, Wenlin; Li, Li

2013-03-01

We have synthesized an efficient and highly sensitive nanoamplifier composed of gadolinium-doped silica nanoparticles and gold nanoparticles (AuNPs). Magnetic resonance imaging (MRI) in vitro and in vivo assays revealed enhancement of signal sensitivity, which may be explained by electron transfer between water and gadolinium-doped nanoparticles, apparent in the presence of gold. In vitro and in vivo evaluation demonstrated nanoamplifier incurred minimal cytotoxicity and immunotoxicity, increased stability, and gradual excretion patterns. Tumor targeted properties were preliminarily determined when the nanoamplifier was injected into mouse models of colon cancer liver metastasis. Furthermore, although AuNPs departed from the nanoamplifiers in specific mice tissues, optical and magnetic resonance imaging was efficient, especially in metastatic tumors. These assays validate our nanoamplifier as an effective MRI signal enhancer with sensitive cancer diagnosis potential.We have synthesized an efficient and highly sensitive nanoamplifier composed of gadolinium-doped silica nanoparticles and gold nanoparticles (AuNPs). Magnetic resonance imaging (MRI) in vitro and in vivo assays revealed enhancement of signal sensitivity, which may be explained by electron transfer between water and gadolinium-doped nanoparticles, apparent in the presence of gold. In vitro and in vivo evaluation demonstrated nanoamplifier incurred minimal cytotoxicity and immunotoxicity, increased stability, and gradual excretion patterns. Tumor targeted properties were preliminarily determined when the nanoamplifier was injected into mouse models of colon cancer liver metastasis. Furthermore, although AuNPs departed from the nanoamplifiers in specific mice tissues, optical and magnetic resonance imaging was efficient, especially in metastatic tumors. These assays validate our nanoamplifier as an effective MRI signal enhancer with sensitive cancer diagnosis potential. Electronic supplementary information

Hepatic reaction dose for parenchymal changes on Gd-EOB-DTPA-enhanced magnetic resonance images after stereotactic body radiation therapy for hepatocellular carcinoma.

PubMed

Jung, Jinhong; Yoon, Sang Min; Cho, Byungchul; Choi, Young Eun; Kwak, Jungwon; Kim, So Yeon; Lee, Sang-Wook; Ahn, Seung Do; Choi, Eun Kyung; Kim, Jong Hoon

2016-02-01

The present study evaluated the threshold dose for hepatic parenchymal changes on gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance (MR) images after stereotactic body radiation therapy (SBRT) for hepatocellular carcinoma (HCC). Twenty patients with available data of follow-up MR images acquired 2-4 months after completion of SBRT were selected among the registered patients. SBRT was performed using multiple coplanar and non-coplanar beams with energies of 6 or 15 MV. All patients were treated with doses of 45 Gy administered in three fractions over 3 consecutive days. For image registration between planning computed tomography (CT) and MR images, landmark-based rigid body registration was performed using MIM software. Seventeen patients were included in the analysis. The median discrepancies between planning CT and MR images in the left-right, anterior-posterior and superior-inferior directions were 1.38 mm, 1.24 mm and 1.72 mm, respectively. The median D50 value for the defect in the hepatobiliary phase of Gd-EOB-DTPA-enhanced MR images after SBRT was 19.8 Gy (range, 14.2-28.7 Gy), with R(2) values ranging from 0.76 to 0.99. The threshold dose for parenchymal changes in the hepatobiliary phase of Gd-EOB-DTPA-enhanced MR images performed 2-4 months after 45 Gy of SBRT in three fractions was approximately 20 Gy. Our results provide the basis for further research on the functional loss of liver parenchyma after SBRT. © 2015 The Royal Australian and New Zealand College of Radiologists.

Chelating DTPA amphiphiles: ion-tunable self-assembly structures and gadolinium complexes.

PubMed

Moghaddam, Minoo J; de Campo, Liliana; Kirby, Nigel; Drummond, Calum J

2012-10-05

A series of chelating amphiphiles and their gadolinium (Gd(III)) metal complexes have been synthesized and studied with respect to their neat and lyotropic liquid crystalline phase behavior. These amphiphiles have the ability to form ion-tunable self-assembly nanostructures and their associated Gd(III) complexes have potential as magnetic resonance imaging (MRI) contrast enhancement agents. The amphiphiles are composed of diethylenetriaminepentaacetic acid (DTPA) chelates conjugated to one or two oleyl chain(s) (DTPA-MO and DTPA-BO), or isoprenoid-type chain(s) of phytanyl (DTPA-MP and DTPA-BP). The thermal phase behavior of the neat amphiphiles was examined by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and cross polarizing optical microscopy (POM). Self-assembly of neat amphiphiles and their associated Gd complexes, as well as their lyotropic phase behavior in water and sodium acetate solutions of different ionic strengths, were examined by POM and small and wide angle X-ray scattering (SWAXS). All neat amphiphiles exhibited lamellar structures. The non-complexed amphiphiles showed a variety of lyotropic phases depending on the number and nature of the hydrophobic chain in addition to the ionic state of the hydration. Upon hydration with increased Na-acetate concentration and the subtle changes in the effective headgroup size, the interfacial curvature of the amphiphile increased, altering the lyotropic liquid crystalline structures towards higher order mesophases such as the gyroid (Ia3d) bicontinuous cubic phase. The chelation of Gd with the DTPA amphiphiles resulted in lamellar crystalline structures for all the neat amphiphiles. Upon hydration with water, the Gd-complexed mono-conjugates formed micellar or vesicular self-assemblies, whilst the bis-conjugates transformed only partially into lyotropic liquid crystalline mesophases.

Graphene Oxide and Gadolinium-Chelate Functionalized Poly(lactic acid) Nanocapsules Encapsulating Perfluorooctylbromide for Ultrasound/Magnetic Resonance Bimodal Imaging Guided Photothermal Ablation of Cancer.

PubMed

Li, Zhenglin; Ke, Hengte; Wang, Jinrui; Miao, Zhaohua; Yue, Xiuli

2016-03-01

This paper successfully fabricated a novel multifunctional theranostic agent (PFOB@PLA/GO/Gd-DTPA NCs) by loading perfluorooctylbromide (PFOB) into poly(lactic acid) (PLA) nanocapsules (NCs) followed by surface functionalization with graphene oxide (GO) and gadolinium-chelate (Gd-DTPA). It was found that the resulting nanoagent could serve as a contrast agent simultaneously to enhance ultrasound (US) and magnetic resonance imaging (MRI). Benefiting from the strong absorption in the near infrared (NIR) region, the nanocapsules could efficiently kill cancer cells under NIR laser irradiation. Thus, such a single theranostic agent with the combination of realtime US imaging and high-resolution MR imaging could achieve great therapeutic effectiveness without systemic damage to the body. In addition, the cytotoxicity assay on HUVEC cells revealed a good biocompatibility of PFOB@PLA/GO/Gd-DTPA NCs, showing that the versatile nanocapsule system may hold great potential as an effective nanoplatform for contrast enhanced imaging guided photothermal therapy.

Bi-atrial fibrosis detected using three-dimensional late gadolinium enhancement magnetic resonance imaging in a patient with cardiac sarcoidosis.

PubMed

Spence, Stewart; Pena, Elena; Thornhill, Rebecca E; Nery, Pablo B; Birnie, David H

2018-05-01

Presented is the case of a 62-year old male with a history of sarcoidosis and sinus node dysfunction, who underwent late gadolinium enhancement magnetic resonance imaging, which demonstrated left ventricular hyperenhancement and bi-atrial fibrosis.

Differences in perilymphatic space enhancement and adverse inflammatory reaction after intratympanic injection of two different gadolinium agents: A 9.4-T magnetic resonance imaging study.

PubMed

Park, Mina; Lee, Ho Sun; Kim, Hyeonjin; Oh, Seung Ha; Lee, Jun Ho; Suh, Myung-Whan

2016-03-01

To compare the inner ear enhancement after intratympanic injection of two widely used gadolinium (Gd) agents by 9.4 T micro-magnetic resonance imaging (MRI) and to investigate the effects of Gd on the inner ear. Twelve ears of six rats received intratympanic administration of 1/5 diluted Gd agents: gadoterate meglumine (Gd-DTPA) for the left ear and gadodiamide (Gd-DTPA-BMA) for the right ear. MRI was performed every 30 min from 1 to 4 h after administration. The normalized signal intensity was evaluated by quantitative analysis at each cochlear fluid compartment. Eight, six, and seven ears treated with Gd-DTPA, Gd-DPTA-BMA, and nothing as controls, respectively, were processed for histological evaluation after MRI. After hematoxylin & eosin staining, adverse inflammatory reactions were evaluated for turbid aggregation and lymphocytes. The perilymphatic enhancement of Gd-DTPA was superior to that of Gd-DTPA-BMA regardless of cochlear turn, compartment, and time point. Inflammatory reactions were found in 4/8 (50.0%) and 4/6 (66.6%) ears administered Gd-DTPA and Gd-DTPA-BMA, respectively. Regardless of the contrast agent used, inflammatory reactions were most definite in the scala tympani of the basal turn, i.e., near the round window. Slightly greater inflammatory reactions were observed in ears injected with Gd-DTPA-BMA compared to Gd-DTPA although the difference was not statistically significant. No inflammatory reaction was observed in any of the seven controls. The auditory brainstem response threshold was 11.8 ± 2.5 dB SPL before IT Gd injection and it did not change for up to 5 days (15.4 ± 6.6 dB SPL) post-injection. Gd-DTPA was superior to Gd-DTPA-BMA for visualization of the inner ear. Administration of diluted Gd agents intratympanically may induce considerable inflammatory reactions in the inner ear. Copyright © 2015 Elsevier B.V. All rights reserved.

Synthesis route and three different core-shell impacts on magnetic characterization of gadolinium oxide-based nanoparticles as new contrast agents for molecular magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Azizian, Gholamreza; Riyahi-Alam, Nader; Haghgoo, Soheila; Moghimi, Hamid Reza; Zohdiaghdam, Reza; Rafiei, Behrooz; Gorji, Ensieh

2012-10-01

Despite its good resolution, magnetic resonance imaging intrinsically has low sensitivity. Recently, contrast agent nanoparticles have been used as sensitivity and contrast enhancer. The aim of this study was to investigate a new controlled synthesis method for gadolinium oxide-based nanoparticle preparation. For this purpose, diethyleneglycol coating of gadolinium oxide (Gd2O3-DEG) was performed using new supervised polyol route, and small particulate gadolinium oxide (SPGO) PEGylation was obtained with methoxy-polyethylene-glycol-silane (550 and 2,000 Da) coatings as SPGO-mPEG-silane550 and 2,000, respectively. Physicochemical characterization and magnetic properties of these three contrast agents in comparison with conventional Gd-DTPA were verified by dynamic light scattering transmission electron microscopy, Fourier transform infrared spectroscopy, inductively coupled plasma, X-ray diffraction, vibrating sample magnetometer, and the signal intensity and relaxivity measurements were performed using 1.5-T MRI scanner. As a result, the nanoparticle sizes of Gd2O3-DEG, SPGO-mPEG-silane550, and SPGO-mPEG-silane2000 could be reached to 5.9, 51.3, 194.2 nm, respectively. The image signal intensity and longitudinal ( r 1) and transverse relaxivity ( r 2) measurements in different concentrations (0.3 to approximately 2.5 mM), revealed the r 2/ r 1 ratios of 1.13, 0.89, 33.34, and 33.72 for Gd-DTPA, Gd2O3-DEG, SPGO-mPEG-silane550, and SPGO-mPEG-silane2000, respectively. The achievement of new synthesis route of Gd2O3-DEG resulted in lower r 2/ r 1 ratio for Gd2O3-DEG than Gd-DTPA and other previous synthesized methods by this and other groups. The smaller r 2/ r 1 ratios of two PEGylated-SPGO contrast agents in our study in comparison with r 2/ r 1 ratio of previous PEGylation ( r 2/ r 1 = 81.9 for mPEG-silane 6,000 MW) showed that these new three introduced contrast agents could potentially be proper contrast enhancers for cellular and molecular MR imaging.

Gadolinium-enhanced 7.0 T magnetic resonance imaging assessment of the aqueous inflow in rat eyes in vivo.

PubMed

Li, Lu; Yuan, Yuxiang; Chen, Liwen; Li, Mu; Ji, Pingting; Gong, Jieling; Zhao, Yin; Zhang, Hong

2017-09-01

The goal of this study was to calculate the anterior chamber volume and assess aqueous inflow in rat eyes in vivo, under anesthetic condition. Gadolinium-contrast agent (Gd-DTPA, 234.5 mg/ml) was administered to Sprague-Dawley rat eyes via anterior chamber injection or instillation of 234.5 or 117.25 mg/ml Gd-DTPA in 0.2% azone as eye drops, and changes of Gd signal visualized by 7.0 T magnetic resonance imaging (MRI). The safety of local application of Gd-DTPA and azone were performed after MRI scanning. The anterior chamber injection of Gd-DTPA (234.5 mg/ml) group was used for anterior chamber volume and aqueous inflow calculating. Serial changes in Gd-DTPA relative concentration in the anterior chamber was determined based on the initial Gd signal gray values and the initial relative concentration of Gd-DTPA after anterior chamber Gd-DTPA injection. The mean aqueous inflow in rat eyes in vivo was assessed based on changes in Gd-DTPA relative concentration and the anterior chamber volume. Eye drops of Gd-DTPA (234.5 mg/ml) in 0.2% azone readily allowed safe assessment of the aqueous inflow by 7.0 T MRI. Under anesthetic condition in vivo, the mean anterior chamber volume (ACV) in rats was 8493.6 ± 657.4 μm 3 , no differences were observed in the aqueous inflow measured by topical instillation of 234.5 mg/ml Gd-DTPA in 0.2% azone (0.182 ± 0.011 μl/min) between that measured by anterior chamber injection (0.165 ± 0.041 μl/min, P > 0.05), Timolol reduced aqueous inflow to 0.124 ± 0.020 μl/min (P < 0.05). Our results indicated that Gd-enhanced 7.0 T MRI allows evaluation of the Gd signal variation and anterior chamber volume in rats in vivo. The aqueous inflow calculation via non-invasive local application of 234.5 mg/ml Gd-DTPA can be assessed by the variability of relative concentration of Gd-DTPA in anterior chamber and ACV in vivo, under anesthetic condition. Copyright © 2017 Elsevier Ltd. All rights reserved.

Impaired hepatic Gd-EOB-DTPA enhancement after radioembolisation of liver malignancies.

PubMed

Powerski, Maciej Janusz; Scheurig-Münkler, Christian; Hamm, Bernd; Gebauer, Bernhard

2014-08-01

To evaluate the uptake of the liver-specific magnetic resonance imaging (MRI) contrast agent gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) by functional liver parenchyma after radioembolisation (RE) of hepatic malignancies. Uptake of Gd-EOB-DTPA prior to RE versus 60+/-24d and 126+/-32d after RE was compared in a group of 33 patients with primary or secondary hepatic malignancies. In patients who underwent single-lobe treatment, left and right lobes were compared 59+/-24 days after RE. Gd-EOB-DTPA uptake was determined as follows: ratio of mean signal intensity in liver parenchyma to muscle in Gd-EOB-DTPA-enhanced T1-weighted MRI was subtracted from ratio of mean intensity in liver parenchyma to muscle in unenhanced T1-weighted MRI. Gd-EOB-DTPA uptake in liver parenchyma was 0.845+/-0.29 before RE, 0.615+/-0.38 (P = 0.0022) at day 60+/-24, and 0.739+/-0.30 at day 126+/-32 after RE. In cases of single-lobe treatment, Gd-EOB-DTPA uptake was 0.581+/-0.256 for treated and 0.828+/-0.32 (P = 0.0164) for untreated hepatic lobes. Uptake of Gd-EOB-DTPA by liver parenchyma is impaired after RE, indicating dysfunction of the local hepatic system. These findings suggest that Gd-EOB-DTPA-enhanced MRI has the potential to be used for monitoring liver damage after RE. © 2014 The Royal Australian and New Zealand College of Radiologists.

Synthesis and evaluation of gadolinium complexes based on PAMAM as MRI contrast agents.

PubMed

Yan, Guo-Ping; Hu, Bin; Liu, Mai-Li; Li, Li-Yun

2005-03-01

Diethylenetriaminepentaacetic acid (DTPA) and pyridoxamine (PM) were incorporated into the amine groups on the surface of ammonia-core poly(amidoamine) dendrimers (PAMAM, Generation 2.0-5.0) to obtain dendritic ligands. These dendritic ligands were reacted with gadolinium chloride to yield the corresponding dendritic gadolinium (Gd) complexes. The dendritic ligands and their gadolinium complexes were characterized by(1)HNMR, IR, UV and elemental analysis. Relaxivity studies showed that the dendritic gadolinium complexes possessed higher relaxation effectiveness compared with the clinically used Gd-DTPA. After administration of the dendritic gadolinium complexes (0.09 mmol kg(-1) ) to rats, magnetic resonance imaging of the liver indicated that the dendritic gadolinium complexes containing pyridoxamine groups enhanced the contrast of the MR images of the liver, provided prolonged intravascular duration and produced highly contrasted visualization of blood vessels.

Hybrid Calcium Phosphate-Polymeric Micelles Incorporating Gadolinium Chelates for Imaging-Guided Gadolinium Neutron Capture Tumor Therapy.

PubMed

Mi, Peng; Dewi, Novriana; Yanagie, Hironobu; Kokuryo, Daisuke; Suzuki, Minoru; Sakurai, Yoshinori; Li, Yanmin; Aoki, Ichio; Ono, Koji; Takahashi, Hiroyuki; Cabral, Horacio; Nishiyama, Nobuhiro; Kataoka, Kazunori

2015-06-23

Gadolinium (Gd) chelates-loaded nanocarriers have high potential for achieving magnetic resonance imaging (MRI)-guided Gd neutron capture therapy (GdNCT) of tumors. Herein, we developed calcium phosphate micelles hybridized with PEG-polyanion block copolymers, and incorporated with the clinical MRI contrast agent Gd-diethylenetriaminepentaacetic acid (Gd-DTPA/CaP). The Gd-DTPA/CaP were nontoxic to cancer cells at the concentration of 100 μM based on Gd-DTPA, while over 50% of the cancer cells were killed by thermal neutron irradiation at this concentration. Moreover, the Gd-DTPA/CaP showed a dramatically increased accumulation of Gd-DTPA in tumors, leading to the selective contrast enhancement of tumor tissues for precise tumor location by MRI. The enhanced tumor-to-blood distribution ratio of Gd-DTPA/CaP resulted in the effective suppression of tumor growth without loss of body weight, indicating the potential of Gd-DTPA/CaP for safe cancer treatment.

Feasibility of gadoteric acid for delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) at the wrist and knee and comparison with Gd-DTPA.

PubMed

Rehnitz, Christoph; Klaan, Bastian; Do, Thuy; Barié, Alexander; Kauczor, Hans-Ulrich; Weber, Marc-André

2017-11-01

To assess the feasibility of gadoteric acid for delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) and to compare the dGEMRIC values obtained using gadoteric acid with those obtained by an equimolar dose of Gd-DTPA. At 3T, dGEMRIC of the wrist was performed twice using a T 1 -weighted 3D-volumetric interpolated breath-hold examination sequence in 16 healthy volunteers (10 women; mean age 26.0 years) using gadoteric acid first and Gd-DTPA 3 weeks later. In addition, 24 patients with knee pain were examined using gadoteric acid (n = 12; seven women; mean age 45.8 years) or Gd-DTPA (n = 12; four women; mean age 47.1 years). T 1 values, the relative decrease in T 1 , and the delta R1 were compared using t-tests. Interobserver agreement was assessed using the intraclass correlation (ICC) between two independent readers. At the wrist, there was no significant difference in delta R1 values (0.34 ± 0.10/s, 95% confidence interval [0.30;0.38]/s for gadoteric acid and 0.32 ± 0.09 [0.29;0.35]/s for Gd-DTPA, P = 0.24) or the relative decrease in T 1 (0.25 ± 0.06 [0.29;0.35] msec for gadoteric acid and 0.24 ± 0.05 [0.22;0.27] msec for Gd-DTPA, P = 0.35). High observer agreement was found at precontrast (ICC = 0.87, P < 0.001) and postcontrast (ICC = 0.89, P < 0.001). Similarly, at the knee, there was no significant difference in delta R1 (0.39 ± 0.18 [0.32;0.47]/s for gadoteric acid and 0.41 ± 0.09 [0.38;0.45]/s for Gd-DTPA, P = 0.59) or the relative decrease in T 1 (0.30 ± 0.10 [0.26;0.34] msec for gadoteric acid and 0.33 ± 0.05 [0.30;0.35] msec for Gd-DTPA, P = 0.28). High ICCs of 0.96 (P < 0.01) were noted both at precontrast and postcontrast. dGEMRIC using gadoteric acid is feasible and yields comparable values when compared with Gd-DTPA. 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017;46:1433-1440. © 2017 International Society for Magnetic Resonance in Medicine.

Investigation of suspected Guillain-Barre syndrome in childhood: what is the role for gadolinium enhanced magnetic resonance imaging of the spine?

PubMed

Smith, Nicholas; Pereira, John; Grattan-Smith, Padraic

2014-10-01

To review the role of gadolinium-enhanced magnetic resonance imaging of the spine in the diagnosis of paediatric Guillain-Barre syndrome and compare it with nerve conduction studies and cerebrospinal fluid analysis. A retrospective review of investigations undertaken in children admitted to our institution with acute Guillain-Barre syndrome over a 10-year period was performed. Seven of eight children (88%) displayed post-gadolinium nerve root enhancement consistent with Guillain-Barre syndrome. This compared with supportive nerve conduction studies in 21/24 children (88%) and cerebrospinal fluid protein analysis consistent with the diagnosis in 16/20 children (80%). Nerve conduction studies are the recognised 'gold standard' technique for confirming a clinical diagnosis of Guillain-Barre syndrome. In this study, a high positive rate was demonstrated. While more experience is necessary, this study and the literature support gadolinium enhanced magnetic resonance imaging of the spine as a valuable, although not necessarily superior, investigation in the diagnosis of Guillain-Barre syndrome. It may be of particular benefit when specialist neurophysiology expertise is unavailable. © 2010 The Authors. Journal compilation © 2010 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

Biodegradable gadolinium-chelated cationic poly(urethane amide) copolymers for gene transfection and magnetic resonance imaging.

PubMed

Gao, Xiaolong; Wang, Gangmin; Shi, Ting; Shao, Zhihong; Zhao, Peng; Shi, Donglu; Ren, Jie; Lin, Chao; Wang, Peijun

2016-08-01

Theranostic nano-polyplexes containing gene and imaging agents hold a great promise for tumor diagnosis and therapy. In this work, we develop a group of new gadolinium (Gd)-chelated cationic poly(urethane amide)s for gene delivery and T1-weighted magnetic resonance (MR) imaging. Cationic poly(urethane amide)s (denoted as CPUAs) having multiple disulfide bonds, urethane and amide linkages were synthesized by stepwise polycondensation reaction between 1,4-bis(3-aminopropyl)piperazine and a mixture of di(4-nitrophenyl)-2, 2'-dithiodiethanocarbonate (DTDE-PNC) and diethylenetriaminepentaacetic acid (DTPA) dianhydride at varied molar ratios. Then, Gd-chelated CPUAs (denoted as GdCPUAs) were produced by chelating Gd(III) ions with DTPA residues of CPUAs. These GdCPUAs could condense gene into nanosized and positively-charged polyplexes in a physiological condition and, however, liberated gene in an intracellular reductive environment. In vitro transfection experiments revealed that the GdCPUA at a DTDE-PNC/DTPA residue molar ratio of 85/15 induced the highest transfection efficiency in different cancer cells. This efficiency was higher than that yielded with 25kDa branched polyethylenimine as a positive control. GdCPUAs and their polyplexes exhibited low cytotoxicity when an optimal transfection activity was detected. Moreover, GdCPUAs may serve as contrast agents for T1-weighted magnetic resonance imaging. The results of this work indicate that biodegradable Gd-chelated cationic poly(urethane amide) copolymers have high potential for tumor theranostics. Copyright © 2016 Elsevier B.V. All rights reserved.

Development and validation of a predictor of insufficient enhancement during the hepatobiliary phase of Gd-EOB-DTPA-enhanced magnetic resonance imaging.

PubMed

Cui, Enming; Long, Wansheng; Luo, Liangping; Hu, Maoqing; Huang, Liebin; Chen, Xiangmeng

2017-10-01

Background Insufficient enhancement of liver parenchyma negatively affects diagnostic accuracy of Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI). Currently, there is no reliable method for predicting insufficient enhancement during the hepatobiliary phase (HBP) in Gd-EOB-DTPA-enhanced MRI. Purpose To develop a predictor for insufficient enhancement of liver parenchyma during HBP in Gd-EOB-DTPA-enhanced MRI. Material and Methods In order to formulate a HBP enhancement test (HBP-ET), clinical factors associated with relative enhancement ratio (RER) of liver parenchyma were retrospectively determined from the datasets of 156 patients (Development group) who underwent Gd-EOB-DTPA-enhanced MRI between November 2012 and May 2015. The independent clinical factors were identified by Pearson's correlation and multiple stepwise regression analysis; the performance of HBP-ET was compared to Child-Pugh score (CPS), Model for End-stage Liver Disease score (MELD), and total bilirubin (TBIL) using receiver operating characteristic (ROC) curve analysis. The datasets of 52 patients (Validation group), which were examined between June 2015 and Oct 2015, were applied to validate the HBP-ET. Results Six biochemical parameters independently influenced RER and were used to develop HBP-ET. The mean HBP-ET score of patients with insufficient enhancement was significantly higher than that of patients with sufficient enhancement ( P < 0.001) in both the Development and Validation groups. HBP-ET (area under the curve [AUC] = 0.895) had better performance in predicting insufficient enhancement than CPS (AUC = 0.707), MELD (AUC = 0.798), and TBIL (AUC = 0.729). Conclusion The HBP-ET is more accurate than routine indicators in predicting insufficient enhancement during HBP, which is valuable to aid clinical decisions.

Cross-linkable liposomes stabilize a magnetic resonance contrast-enhancing polymeric fastener.

PubMed

Smith, Cartney E; Kong, Hyunjoon

2014-04-08

Liposomes are commonly used to deliver drugs and contrast agents to their target site in a controlled manner. One of the greatest obstacles in the performance of such delivery vehicles is their stability in the presence of serum. Here, we demonstrate a method to stabilize a class of liposomes that load gadolinium, a magnetic resonance (MR) contrast agent, as a model cargo on their surfaces. We hypothesized that the sequential adsorption of a gadolinium-binding chitosan fastener on the liposome surface followed by covalent cross-linking of the lipid bilayer would provide enhanced stability and improved MR signal in the presence of human serum. To investigate this hypothesis, liposomes composed of diyne-containing lipids were assembled and functionalized via chitosan conjugated with a hydrophobic anchor and diethylenetriaminepentaacetic acid (DTPA). This postadsorption cross-linking strategy served to stabilize the thermodynamically favorable association between liposome and polymeric fastener. Furthermore, the chitosan-coated, cross-linked liposomes proved more effective as delivery vehicles of gadolinium than uncross-linked liposomes due to the reduced liposome degradation and chitosan desorption. Overall, this study demonstrates a useful method to stabilize a broad class of particles used for systemic delivery of various molecular payloads.

Cross-Linkable Liposomes Stabilize a Magnetic Resonance Contrast-Enhancing Polymeric Fastener

PubMed Central

2015-01-01

Liposomes are commonly used to deliver drugs and contrast agents to their target site in a controlled manner. One of the greatest obstacles in the performance of such delivery vehicles is their stability in the presence of serum. Here, we demonstrate a method to stabilize a class of liposomes that load gadolinium, a magnetic resonance (MR) contrast agent, as a model cargo on their surfaces. We hypothesized that the sequential adsorption of a gadolinium-binding chitosan fastener on the liposome surface followed by covalent cross-linking of the lipid bilayer would provide enhanced stability and improved MR signal in the presence of human serum. To investigate this hypothesis, liposomes composed of diyne-containing lipids were assembled and functionalized via chitosan conjugated with a hydrophobic anchor and diethylenetriaminepentaacetic acid (DTPA). This postadsorption cross-linking strategy served to stabilize the thermodynamically favorable association between liposome and polymeric fastener. Furthermore, the chitosan-coated, cross-linked liposomes proved more effective as delivery vehicles of gadolinium than uncross-linked liposomes due to the reduced liposome degradation and chitosan desorption. Overall, this study demonstrates a useful method to stabilize a broad class of particles used for systemic delivery of various molecular payloads. PMID:24635565

Hydrothermally synthesized PEGylated calcium phosphate nanoparticles incorporating Gd-DTPA for contrast enhanced MRI diagnosis of solid tumors.

PubMed

Mi, Peng; Kokuryo, Daisuke; Cabral, Horacio; Kumagai, Michiaki; Nomoto, Takahiro; Aoki, Ichio; Terada, Yasuko; Kishimura, Akihiro; Nishiyama, Nobuhiro; Kataoka, Kazunori

2014-01-28

Organic-inorganic hybrid nanoparticles with calcium phosphate (CaP) core and PEGylated shell were developed to incorporate magnetic resonance imaging (MRI) contrast agent diethylenetriaminepentaacetic acid gadolinium (III) (Gd-DTPA) for noninvasive diagnosis of solid tumors. A two-step preparation method was applied to elaborate hybrid nanoparticles with a z-average hydrodynamic diameter about 80nm, neutral surface ξ-potential and high colloidal stability in physiological environments by self-assembly of poly(ethylene glycol)-b-poly(aspartic acid) block copolymer, Gd-DTPA, and CaP in aqueous solution, followed with hydrothermal treatment. Incorporation into the hybrid nanoparticles allowed Gd-DTPA to show significant enhanced retention ratio in blood circulation, leading to high accumulation in tumor positions due to enhanced permeability and retention (EPR) effect. Moreover, Gd-DTPA revealed above 6 times increase of relaxivity in the nanoparticle system compared to free form, and eventually, selective and elevated contrast enhancements in the tumor positions were observed. These results indicate the high potential of Gd-DTPA-loaded PEGylated CaP nanoparticles as a novel contrast agent for noninvasive cancer diagnosis. Copyright © 2013 Elsevier B.V. All rights reserved.

Serial nonenhancing magnetic resonance imaging scans of high grade glioblastoma multiforme.

PubMed Central

Moore-Stovall, J.; Venkatesh, R.

1993-01-01

Magnetic resonance imaging (MRI) from clinical experience has proven to be superior to all other diagnostic imaging modalities, including computed tomography (CT) in the detection of intracranial neoplasms. Although glioblastoma multiforme presents a challenge for all diagnostic imaging modalities including MRI, MRI is paramount to CT in detecting subtle abnormal water accumulation in brain tissue caused by tumor even before there is disruption of the blood brain barrier. Currently, clinical research and investigational trials on nonionic gadolinium contrast agents have proven that nonionic gadolinium HP-DO3A (ProHance) contrast agents have lower osmolality and greater stability, which make them superior compounds to gadolinium diethylenetriamine-pentacetic acid (Gd-DTPA). Therefore, the nonionic gadolinium contrasts have been safely administered more rapidly, in higher or multiple doses for contrast enhanced MRI without adverse side effects or changes in serum iron or total bilirubin, and the intensity of the area of enhancement and number of lesions detected were superior to that of Gd-DTPA (Magnevist) at the standard dose (0.1 mmol/Kg). Perhaps if the nonionic gadolinium contrast agent, ProHance, had been approved by the Food and Drug Administration (FDA) when this MRI was performed in 1990 it would have aided in providing contrast enhancement and visualization of the tumor lesion to assist in patient diagnosis and management. Magnetic resonance imaging also provides unique multiplanar capabilities that allow for optimal visualization of the temporal and occipital lobes of the brain without bone interference.(ABSTRACT TRUNCATED AT 250 WORDS) Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9A Figure 9B Figure 10 Figure 11 Figure 12 Figure 13 PMID:8382751

Assessment of liver function in primary biliary cirrhosis using Gd-EOB-DTPA-enhanced liver MRI.

PubMed

Nilsson, Henrik; Blomqvist, Lennart; Douglas, Lena; Nordell, Anders; Jonas, Eduard

2010-10-01

Gd-EOB-DTPA (gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid) is a gadolinium-based hepatocyte-specific contrast agent for magnetic resonance imaging (MRI). The aim of this study was to determine whether the hepatic uptake and excretion of Gd-EOB-DTPA differ between patients with primary biliary cirrhosis (PBC) and healthy controls, and whether differences could be quantified. Gd-EOB-DTPA-enhanced liver MRI was performed in 20 healthy volunteers and 12 patients with PBC. The uptake of Gd-EOB-DTPA was assessed using traditional semi-quantitative parameters (C(max) , T(max) and T(1/2) ), as well as model-free parameters derived after deconvolutional analysis (hepatic extraction fraction [HEF], input-relative blood flow [irBF] and mean transit time [MTT]). In each individual, all parameters were calculated for each liver segment and the median of the segmental values was used to define a global liver median (GLM). Although the PBC patients had relatively mild disease according to their Model for End-stage Liver Disease (MELD), Child-Pugh and Mayo risk scores, they had significantly lower HEF and shorter MTT values compared with the healthy controls. These differences significantly increased with increasing MELD and Child-Pugh scores. Dynamic hepatocyte-specific contrast-enhanced MRI (DHCE-MRI) has a potential role as an imaging-based liver function test. The high spatial resolution of MRI enables hepatic function to be assessed on segmental and sub-segmental levels. © 2010 International Hepato-Pancreato-Biliary Association.

Radiation-induced optic neuropathy: A magnetic resonance imaging study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guy, J.; Mancuso, A.; Beck, R.

1991-03-01

Optic neuropathy induced by radiation is an infrequent cause of delayed visual loss that may at times be difficult to differentiate from compression of the visual pathways by recurrent neoplasm. The authors describe six patients with this disorder who experienced loss of vision 6 to 36 months after neurological surgery and radiation therapy. Of the six patients in the series, two had a pituitary adenoma and one each had a metastatic melanoma, multiple myeloma, craniopharyngioma, and lymphoepithelioma. Visual acuity in the affected eyes ranged from 20/25 to no light perception. Magnetic resonance (MR) imaging showed sellar and parasellar recurrence ofmore » both pituitary adenomas, but the intrinsic lesions of the optic nerves and optic chiasm induced by radiation were enhanced after gadolinium-diethylenetriaminepenta-acetic acid (DTPA) administration and were clearly distinguishable from the suprasellar compression of tumor. Repeated MR imaging showed spontaneous resolution of gadolinium-DTPA enhancement of the optic nerve in a patient who was initially suspected of harboring recurrence of a metastatic malignant melanoma as the cause of visual loss. The authors found the presumptive diagnosis of radiation-induced optic neuropathy facilitated by MR imaging with gadolinium-DTPA. This neuro-imaging procedure may help avert exploratory surgery in some patients with recurrent neoplasm in whom the etiology of visual loss is uncertain.« less

Macromolecular and Dendrimer Based Magnetic Resonance Contrast Agents

PubMed Central

Bumb, Ambika; Brechbiel, Martin W.; Choyke, Peter

2010-01-01

Magnetic resonance imaging (MRI) is a powerful imaging modality that can provide an assessment of function or molecular expression in tandem with anatomic detail. Over the last 20–25 years, a number of gadolinium based MR contrast agents have been developed to enhance signal by altering proton relaxation properties. This review explores a range of these agents from small molecule chelates, such as Gd-DTPA and Gd-DOTA, to macromolecular structures composed of albumin, polylysine, polysaccharides (dextran, inulin, starch), poly(ethylene glycol), copolymers of cystamine and cystine with GD-DTPA, and various dendritic structures based on polyamidoamine and polylysine (Gadomers). The synthesis, structure, biodistribution and targeting of dendrimer-based MR contrast agents are also discussed. PMID:20590365

Gadolinium enhanced cardiovascular magnetic resonance in Anderson-Fabry disease. Evidence for a disease specific abnormality of the myocardial interstitium.

PubMed

Moon, James C C; Sachdev, Bhavesh; Elkington, Andrew G; McKenna, William J; Mehta, Atul; Pennell, Dudley J; Leed, Philip J; Elliott, Perry M

2003-12-01

Anderson-Fabry Disease (AFD), an X-linked disorder of sphingolipid metabolism, is a cause of idiopathic left ventricular hypertrophy but the mechanism of hypertrophy is poorly understood. Gadolinium enhanced cardiovascular magnetic resonance can detect focal myocardial fibrosis. We hypothesised that hyperenhancement would be present in AFD. Eighteen males (mean 43+/-14 years) and eight female heterozygotes (mean 48+/-12 years) with AFD underwent cine and late gadolinium cardiovascular magnetic resonance. Nine male (50%) had myocardial hyperenhancement ranging from 3.4% to 20.6% (mean 7.7+/-5.7%) of total myocardium; in males, percentage hyperenhancement related to LV mass index (r=0.78, P=0.0002) but not to ejection fraction or left ventricular volumes. Lesser hyperenhancement was also found in four (50%) heterozygous females (mean 4.6%). In 12 (92%) patients with abnormal gadolinium uptake, hyperenhancement occurred in the basal infero-lateral wall where, unlike myocardial infarction, it was not sub-endocardial. In two male patients with severe LVH (left ventricular hypertrophy) and systolic impairment there was additional hyperenhancement in other myocardial segments. These observations suggests that myocardial fibrosis occurs in AFD and may contribute to the hypertrophy and the natural history of the disease.

Prognostic Value of Late Gadolinium Enhancement Cardiovascular Magnetic Resonance in Cardiac Amyloidosis.

PubMed

Fontana, Marianna; Pica, Silvia; Reant, Patricia; Abdel-Gadir, Amna; Treibel, Thomas A; Banypersad, Sanjay M; Maestrini, Viviana; Barcella, William; Rosmini, Stefania; Bulluck, Heerajnarain; Sayed, Rabya H; Patel, Ketna; Mamhood, Shameem; Bucciarelli-Ducci, Chiara; Whelan, Carol J; Herrey, Anna S; Lachmann, Helen J; Wechalekar, Ashutosh D; Manisty, Charlotte H; Schelbert, Eric B; Kellman, Peter; Gillmore, Julian D; Hawkins, Philip N; Moon, James C

2015-10-20

The prognosis and treatment of the 2 main types of cardiac amyloidosis, immunoglobulin light chain (AL) and transthyretin (ATTR) amyloidosis, are substantially influenced by cardiac involvement. Cardiovascular magnetic resonance with late gadolinium enhancement (LGE) is a reference standard for the diagnosis of cardiac amyloidosis, but its potential for stratifying risk is unknown. Two hundred fifty prospectively recruited subjects, 122 patients with ATTR amyloid, 9 asymptomatic mutation carriers, and 119 patients with AL amyloidosis, underwent LGE cardiovascular magnetic resonance. Subjects were followed up for a mean of 24±13 months. LGE was performed with phase-sensitive inversion recovery (PSIR) and without (magnitude only). These were compared with extracellular volume measured with T1 mapping. PSIR was superior to magnitude-only inversion recovery LGE because PSIR always nulled the tissue (blood or myocardium) with the longest T1 (least gadolinium). LGE was classified into 3 patterns: none, subendocardial, and transmural, which were associated with increasing amyloid burden as defined by extracellular volume (P<0.0001), with transitions from none to subendocardial LGE at an extracellular volume of 0.40 to 0.43 (AL) and 0.39 to 0.40 (ATTR) and to transmural at 0.48 to 0.55 (AL) and 0.47 to 0.59 (ATTR). Sixty-seven patients (27%) died. Transmural LGE predicted death (hazard ratio, 5.4; 95% confidence interval, 2.1-13.7; P<0.0001) and remained independent after adjustment for N-terminal pro-brain natriuretic peptide, ejection fraction, stroke volume index, E/E', and left ventricular mass index (hazard ratio, 4.1; 95% confidence interval, 1.3-13.1; P<0.05). There is a continuum of cardiac involvement in systemic AL and ATTR amyloidosis. Transmural LGE is determined reliably by PSIR and represents advanced cardiac amyloidosis. The PSIR technique provides incremental information on outcome even after adjustment for known prognostic factors. © 2015 The Authors.

Identification and characterization of gadolinium(III) complexes in biological tissue extracts.

PubMed

Kahakachchi, Chethaka L; Moore, Dennis A

2010-07-01

The gadolinium species present in a rat kidney following intravenous administration of a gadolinium-based magnetic resonance contrast agent (Optimark™, Gadoversetamide injection) to a rat was examined in the present study. The major gadolinium species in the supernatant of the rat kidney tissue extracts was determined by reversed-phase liquid chromatography with online inductively coupled plasma optical emission spectrometry (HPLC-ICP-OES). The identity of the compound was established by liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS) detection. The principal gadolinium(III) complex in a rat kidney tissue extract was identified as Gd-DTPA-BMEA 24 Hrs and 7 days after a single intravenous injection of Optimark™ (gadoversetamide; Gd-DTPA-BMEA) at a dose of 5 mmol Gd/kg body weight. The study demonstrated for the first time the feasibility of the use of two complementary techniques, HPLC-ICP-OES and HPLC-ESI-MS to study the in vivo behavior of gadolinium-based magnetic resonance contrast media.

Gadolinium-enhanced inner ear magnetic resonance imaging for evaluation of delayed endolymphatic hydrops, including a bilateral case.

PubMed

Fukushima, Munehisa; Oya, Ryohei; Akazawa, Hitoshi; Tsuruta, Yukinori; Inohara, Hidenori

2016-01-01

The data suggests that gadolinium-enhanced inner ear MR imaging is useful for diagnosis of delayed endolymphatic hydrops (DEH) because it is independent of inner ear function, and the size of the affected endolymphatic space is clearly enlarged. This study was performed to semi-quantitatively evaluate the endolymphatic space in patients with all types of DEH using gadolinium-enhanced inner ear magnetic resonance (MR) imaging. Seven patients (age range = 21-77 years; five female, two male) with ipsilateral DEH (n = 5), contralateral DEH (n = 1), and bilateral DEH (n = 1). All patients underwent 3T MR imaging 4 h after intravenous injection of gadolinium. Software was used to determine the size of the endolymphatic space. Pure tone audiometry and caloric testing using an electronystagmogram were carried out. One side of the endolymphatic space was dominantly extended in patients with ipsilateral DEH, and both sides of the space were extended in patients with contralateral and bilateral DEH. In patients with ipsilateral DEH, the volume ratio of endolymph to vestibule was 2.5-4.3-times that in the unaffected ear. The volume ratio of endolymph to vestibule was nearly equal in patients with contralateral and bilateral DEH.

Comparison of gadolinium-EOB-DTPA-enhanced and diffusion-weighted liver MRI for detection of small hepatic metastases.

PubMed

Shimada, Kotaro; Isoda, Hiroyoshi; Hirokawa, Yuusuke; Arizono, Shigeki; Shibata, Toshiya; Togashi, Kaori

2010-11-01

To compare the accuracy of gadolinium ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI with that of diffusion-weighted MRI (DWI) in the detection of small hepatic metastases (2 cm or smaller). Forty-five patients underwent abdominal MRI at 3 T, including T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), heavily T2WI (HASTE), DWI with a b-value of 500 s/mm(2) and contrast-enhanced MRI with Gd-EOB-DTPA. Two groups were assigned and compared: group A (T1WI, T2WI, HASTE and contrast-enhanced study with Gd-EOB-DTPA), and group B (T1WI, T2WI, HASTE and DWI). Two observers independently interpreted the images obtained in a random order. For all hepatic metastases, the diagnostic performance using each imaging set was evaluated by receiver-operating characteristic (ROC) curve analysis. A total of 51 hepatic metastases were confirmed. The area under the ROC curve (Az) of group A was larger than that of group B, and the difference in the mean Az values between the two image sets was statistically significant, whereas, there were three metastases that lay near thin vessels or among multiple cysts and were better visualised in group B than in group A. Gd-EOB-DTPA-enhanced MRI showed higher accuracy in the detection of small metastases than DWI.

Detection of liver metastasis: is diffusion-weighted imaging needed in Gd-EOB-DTPA-enhanced MR imaging for evaluation of colorectal liver metastases?

PubMed

Tajima, Taku; Akahane, Masaaki; Takao, Hidemasa; Akai, Hiroyuki; Kiryu, Shigeru; Imamura, Hiroshi; Watanabe, Yasushi; Kokudo, Norihiro; Ohtomo, Kuni

2012-10-01

We compared diagnostic ability for detecting hepatic metastases between gadolinium ethoxy benzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) on a 1.5-T system, and determined whether DWI is necessary in Gd-EOB-DTPA-enhanced MRI for diagnosing colorectal liver metastases. We assessed 29 consecutive prospectively enrolled patients with suspected metachronous colorectal liver metastases; all patients underwent surgery and had preoperative Gd-EOB-DTPA-enhanced MRI. Overall detection rate, sensitivity for detecting metastases and benign lesions, positive predictive value, and diagnostic accuracy (Az value) were compared among three image sets [unenhanced MRI (DWI set), Gd-EOB-DTPA-enhanced MRI excluding DWI (EOB set), and combined set]. Gd-EOB-DTPA-enhanced MRI yielded better overall detection rate (77.8-79.0 %) and sensitivity (87.1-89.4 %) for detecting metastases than the DWI set (55.9 % and 64.7 %, respectively) for one observer (P < 0.001). No statistically significant difference was seen between the EOB and combined sets, although several metastases were newly detected on additional DWI. Gd-EOB-DTPA-enhanced MRI yielded a better overall detection rate and higher sensitivity for detecting metastases compared with unenhanced MRI. Additional DWI may be able to reduce oversight of lesions in Gd-EOB-DTPA-enhanced 1.5-T MRI for detecting colorectal liver metastases.

The histological basis of late gadolinium enhancement cardiovascular magnetic resonance in a patient with Anderson-Fabry disease.

PubMed

Moon, James C; Sheppard, Mary; Reed, Emma; Lee, Phillip; Elliott, Perry M; Pennell, Dudley J

2006-01-01

Anderson-Fabry Disease (AFD) is a storage disease that mimics hypertrophic cardiomyopathy. Late gadolinium enhancement (LGE) by cardiovascular magnetic resonance occurs in approximately 50% of patients in the basal inferolateral LV wall, but how an intracellular storage disease causes focal LGE is unknown. We present a whole-heart histological validation that LGE is caused by focal myocardial collagen scarring. This scarring may be the substrate for electrical re-entry and sudden arrhythmic death. The reasons for this distribution of fibrosis are unclear, but may reflect inhomogeneous left ventricular wall stress.

Prognostic Value of Late Gadolinium Enhancement Cardiovascular Magnetic Resonance in Cardiac Amyloidosis

PubMed Central

Fontana, Marianna; Pica, Silvia; Reant, Patricia; Abdel-Gadir, Amna; Treibel, Thomas A.; Banypersad, Sanjay M.; Maestrini, Viviana; Barcella, William; Rosmini, Stefania; Bulluck, Heerajnarain; Sayed, Rabya H.; Patel, Ketna; Mamhood, Shameem; Bucciarelli-Ducci, Chiara; Whelan, Carol J.; Herrey, Anna S.; Lachmann, Helen J.; Wechalekar, Ashutosh D.; Manisty, Charlotte H.; Schelbert, Eric B.; Kellman, Peter; Gillmore, Julian D.; Hawkins, Philip N.

2015-01-01

Background— The prognosis and treatment of the 2 main types of cardiac amyloidosis, immunoglobulin light chain (AL) and transthyretin (ATTR) amyloidosis, are substantially influenced by cardiac involvement. Cardiovascular magnetic resonance with late gadolinium enhancement (LGE) is a reference standard for the diagnosis of cardiac amyloidosis, but its potential for stratifying risk is unknown. Methods and Results— Two hundred fifty prospectively recruited subjects, 122 patients with ATTR amyloid, 9 asymptomatic mutation carriers, and 119 patients with AL amyloidosis, underwent LGE cardiovascular magnetic resonance. Subjects were followed up for a mean of 24±13 months. LGE was performed with phase-sensitive inversion recovery (PSIR) and without (magnitude only). These were compared with extracellular volume measured with T1 mapping. PSIR was superior to magnitude-only inversion recovery LGE because PSIR always nulled the tissue (blood or myocardium) with the longest T1 (least gadolinium). LGE was classified into 3 patterns: none, subendocardial, and transmural, which were associated with increasing amyloid burden as defined by extracellular volume (P<0.0001), with transitions from none to subendocardial LGE at an extracellular volume of 0.40 to 0.43 (AL) and 0.39 to 0.40 (ATTR) and to transmural at 0.48 to 0.55 (AL) and 0.47 to 0.59 (ATTR). Sixty-seven patients (27%) died. Transmural LGE predicted death (hazard ratio, 5.4; 95% confidence interval, 2.1–13.7; P<0.0001) and remained independent after adjustment for N-terminal pro-brain natriuretic peptide, ejection fraction, stroke volume index, E/E′, and left ventricular mass index (hazard ratio, 4.1; 95% confidence interval, 1.3–13.1; P<0.05). Conclusions— There is a continuum of cardiac involvement in systemic AL and ATTR amyloidosis. Transmural LGE is determined reliably by PSIR and represents advanced cardiac amyloidosis. The PSIR technique provides incremental information on outcome even after

Non-hypervascular hypointense nodules on Gd-EOB-DTPA-enhanced MRI as a predictor of outcomes for early-stage HCC.

PubMed

Toyoda, Hidenori; Kumada, Takashi; Tada, Toshifumi; Sone, Yasuhiro; Maeda, Atsuyuki; Kaneoka, Yuji

2015-01-01

In patients with hepatocellular carcinoma (HCC), gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) often identifies non-hypervascular hypointense hepatic nodules during the hepatobiliary phase, but their prognostic significance is unclear. We conducted a prospective observational study to investigate the impact of non-hypervascular hypointense hepatic nodules detected by Gd-EOB-DTPA-enhanced MRI on the outcome of patients with early-stage HCC. Post-treatment recurrence and survival rates were analyzed in 138 patients with non-recurrent, early-stage HCC [Barcelona Clinic Liver Cancer (BCLC) stage 0 or A] and Child-Pugh A liver function according to the presence of non-hypervascular hypointense nodules on pretreatment Gd-EOB-DTPA-enhanced MRI. Non-hypervascular hypointense hepatic nodules were detected in 51 (37.0%) patients with early-stage HCC on pretreatment Gd-EOB-DTPA-enhanced MRI. Recurrence rates were significantly higher in patients with non-hypervascular hypointense nodules (p < 0.0001). Based on a multivariate analysis, the presence of non-hypervascular hypointense hepatic nodules on Gd-EOB-DTPA-enhanced MRI was independently associated with an increased recurrence rate, independent of tumor progression or treatment (p = 0.0005). The survival rate was significantly lower in patients with non-hypervascular hypointense nodules on Gd-EOB-DTPA-enhanced MRI (p = 0.0108). In patients with early-stage typical HCC (BCLC 0 or A), the presence of concurrent non-hypervascular hypointense hepatic nodules in the hepatobiliary phase of pretreatment Gd-EOB-DTPA-enhanced MRI is an indicator of higher likelihood of recurrence after treatment and may be a marker for unfavorable outcome.

Structural, kinetic, and thermodynamic characterization of the interconverting isomers of MS-325, a gadolinium(III)-based magnetic resonance angiography contrast agent.

PubMed

Tyeklar, Zoltan; Dunham, Stephen U; Midelfort, Katarina; Scott, Daniel M; Sajiki, Hirano; Ong, Karen; Lauffer, Randall B; Caravan, Peter; McMurry, Thomas J

2007-08-06

The amphiphilic gadolinium complex MS-325 ((trisodium-{(2-(R)-[(4,4-diphenylcyclohexyl) phosphonooxymethyl] diethylenetriaminepentaacetato) (aquo)gadolinium(III)}) is a contrast agent for magnetic resonance angiography (MRA). MS-325 comprises a GdDTPA core with an appended phosphodiester moiety linked to a diphenylcyclohexyl group to facilitate noncovalent binding to serum albumin and extension of the plasma half-life in vivo. The chiral DTPA ligand (R) was derived from L-serine, and upon complexation with gadolinium, forms two interconvertible diastereomers, denoted herein as isomers A and B. X-ray crystallography of the tris(ethylenediamine)cobalt(III) salt derivative of isomer A revealed a structure in the polar acentric space group P32. The structure consisted of three independent molecules of the gadolinium complex in the asymmetric unit along with three Delta-[Co(en)3]3+ cations, and it represents an unusual example of spontaneous Pasteur resolution of the cobalt cation. The geometry of the coordination core was best described as a distorted trigonal prism, and the final R factor was 5.6%. The configuration of the chiral central nitrogen of the DTPA core was S. The Gd-water (2.47-2.48 A), the Gd-acetate oxygens (2.34-2.42 A), and the Gd-N bond distances (central N, 2.59-2.63 A; terminal N, 2.74-2.80 A) were similar to other reported GdDTPA structures. The structurally characterized single crystal was one of two interconvertable diastereomers (isomers A and B) that equilibrated to a ratio of 1.81 to 1 at pH 7.4 and were separable at elevated pH by ion-exchange chromatography. The rate of isomerization was highly pH dependent: k1 = (1.45 +/- 0.08) x 102[H+] + (4.16 +/- 0.30) x 105[H+]2; k-1 = (2.57 +/- 0.17) x 102[H+] + (7.54 +/- 0.60) x 105[H+]2.

Assessment of Gd-EOB-DTPA-enhanced MRI for HCC and dysplastic nodules and comparison of detection sensitivity versus MDCT.

PubMed

Inoue, Tatsuo; Kudo, Masatoshi; Komuta, Mina; Hayaishi, Sosuke; Ueda, Taisuke; Takita, Masahiro; Kitai, Satoshi; Hatanaka, Kinuyo; Yada, Norihisa; Hagiwara, Satoru; Chung, Hobyung; Sakurai, Toshiharu; Ueshima, Kazuomi; Sakamoto, Michiie; Maenishi, Osamu; Hyodo, Tomoko; Okada, Masahiro; Kumano, Seishi; Murakami, Takamichi

2012-09-01

We aimed to evaluate gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) for the detection of hepatocellular carcinomas (HCCs) and dysplastic nodules (DNs) compared with dynamic multi-detector row computed tomography (MDCT), and to discriminate between HCCs and DNs. Eighty-six nodules diagnosed as HCC or DNs were retrospectively investigated. Gd-EOB-DTPA-enhanced MRI and dynamic MDCT were compared with respect to their diagnostic ability for hypervascular HCCs and detection sensitivity for hypovascular tumors. The ability of hepatobiliary images of Gd-EOB-DTPA-enhanced MRI to discriminate between these nodules was assessed. We also calculated the EOB enhancement ratio of the tumors. For hypervascular HCCs, the diagnostic ability of Gd-EOB-DTPA-enhanced MRI was significantly higher than that of MDCT for tumors less than 2 cm (p = 0.048). There was no difference in the detection of hypervascular HCCs between hepatobiliary phase images of Gd-EOB-DTPA-enhanced MRI (43/45: 96%) and dynamic MDCT (40/45: 89%), whereas the detection sensitivity of hypovascular tumors by Gd-EOB-DTPA-enhanced MRI was significantly higher than that by dynamic MDCT (39/41: 95% vs. 25/41: 61%, p = 0.001). EOB enhancement ratios were decreased in parallel with the degree of differentiation in DNs and HCCs, although there was no difference between DNs and hypovascular well-differentiated HCCs. The diagnostic ability of Gd-EOB-DTPA-enhanced MRI for hypervascular HCCs less than 2 cm was significantly higher than that of MDCT. For hypovascular tumors, the detection sensitivity of hepatobiliary phase images of Gd-EOB-DTPA-enhanced MRI was significantly higher than that of dynamic Gd-EOB-DTPA-enhanced MRI and dynamic MDCT. It was difficult to distinguish between DNs and hypovascular well-differentiated HCCs based on the EOB enhancement ratio.

Gadolinium-based magnetic resonance imaging contrast agents in interventional radiology.

PubMed

Atar, Eli

2004-07-01

Gadolinium-based agents are widely used in magnetic resonance imaging as contrast agents. These agents are radio-opaque enough for diagnostic imaging of the vascular tree by using digitally subtracted images as well as for imaging of the biliary system and the urinary tract. The recommended doses for gadolinium do not impair renal function or cause adverse reactions in patients with iodine sensitivity; thus patients with such conditions can safely undergo diagnostic angiography, either by MRI angiography or by catheterization using gadolinium as contrast agent, for diagnostic and therapeutic purposes.

Single-walled carbon nanotube-loaded doxorubicin and Gd-DTPA for targeted drug delivery and magnetic resonance imaging.

PubMed

Yan, Chenyu; Chen, Chengqun; Hou, Lin; Zhang, Huijuan; Che, Yingyu; Qi, Yuedong; Zhang, Xiaojian; Cheng, Jingliang; Zhang, Zhenzhong

2017-02-01

An aspargine-glycine-arginine (NGR) peptide modified single-walled carbon nanotubes (SWCNTs) system, developed by a simple non-covalent approach, could be loaded with the anticancer drug doxorubicin (DOX) and magnetic resonance imaging (MRI) contrast agent gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA). This DOX- and Gd-DTPA-loaded NGR functionalized SWCNTs (DOX/NGR-SWCNTs/Gd-DPTA) retained both cytotoxicity of DOX and MRI contrast effect of Gd-DPTA. This drug delivery system showed excellent stability in physiological solutions. This DOX/NGR-SWCNTs/Gd-DPTA system could accumulate in tumors and enter into tumor cells, which facilitated combination chemotherapy with diagnosis of tumor in one system. An excellent in vitro anti-tumor effect was shown in MCF-7 cells treated by DOX/NGR-SWCNTs/Gd-DPTA, compared with DOX solution, DOX/SWCNTs and DOX/SWCNTs/Gd-DPTA. In vivo data of DOX/NGR-SWCNTs/Gd-DPTA group in tumor-bearing mice further confirmed that this system performed much higher tumor targeting capacity and anti-tumor efficacy than other control groups.

Gadolinium chloride as a contrast agent for imaging wood composite components by magnetic resonance

Treesearch

Thomas L. Eberhardt; Chi-Leung So; Andrea Protti; Po-Wah So

2009-01-01

Although paramagnetic contrast agents have an established track record in medical uses of magnetic resonance imaging (MRI), only recently has a contrast agent been used for enhancing MRI images of solid wood specimens. Expanding on this concept, wood veneers were treated with a gadolinium-based contrast agent and used in a model system comprising three-ply plywood...

Use of gadolinium chloride as a contrast agent for imaging spruce knots by magnetic resonance

Treesearch

Thomas L. Eberhardt; Chi-Leung So; Amy H. Herlihy; Po-Wah So

2006-01-01

Treatments of knot-containing spruce wood blocks with a paramagnetic salt, gadolinium (III) chloride, in combination with solvent pretreatments, were evaluated as strategies to enhance the visualization of wood features by magnetic resonance imaging (MRI). Initial experiments with clear wood and excised knot samples showed differences in moisture uptake after...

Gadolinium-enhanced cardiovascular magnetic resonance: administered dose in relationship to United States Food and Drug Administration (FDA) guidelines.

PubMed

Nacif, Marcelo S; Arai, Andrew E; Lima, Joao A C; Bluemke, David A

2012-02-29

Myocardial late gadolinium enhancement was originally validated using higher than label-recommended doses of gadolinium chelate. The objective of this study was to evaluate available evidence for various gadolinium dosing regimens used for CMR. The relationship of gadolinium dose warnings (due to nephrogenic systemic fibrosis) announced in 2008 to gadolinium dosing regimens was also examined. We conducted a meta-analysis of peer reviewed publications from January, 2004 to December, 2010. Major subject search headings (MeSh) terms from the National Library of Medicine's PubMed were: contrast media, gadolinium, heart, magnetic resonance imaging; searches were limited to human studies with abstracts published in English. Case reports, review articles, editorials, MRA related papers and all reports that did not indicate gadolinium type or weight-based dose were excluded. For all included references, full text was available to determine the total administered gadolinium dose on a per kg basis. Average and median dose values were weighted by the number of subjects in each study. 399 publications were identified in PubMed; 233 studies matched the inclusion criteria, encompassing 19,934 patients with mean age 54.2 ± 11.4 (range 9.3 to 76 years). 34 trials were related to perfusion testing and 199 to myocardial late gadolinium enhancement. In 2004, the weighted-median and weighted-mean contrast dose were 0.15 and 0.16 ± 0.06 mmol/kg, respectively. Median contrast doses for 2005-2010 were: 0.2 mmol/kg for all years, respectively. Mean contrast doses for the years 2005-2010 were: 0.19 ± 0.03, 0.18 ± 0.04, 0.18 ± 0.10, 0.18 ± 0.03, 0.18 ± 0.04 and 0.18 ± 0.04 mmol/kg, respectively (p for trend, NS). Gadopentetate dimeglumine was the most frequent gadolinium type [114 (48.9%) studies]. No change in mean gadolinium dose was present before, versus after the Food and Drug Administration (FDA) black box warning (p > 0.05). Three multi-center dose ranging trials have been

Gd-EOB-DTPA-enhanced magnetic resonance imaging for focal liver lesions in Chinese patients: a multicenter, open-label, phase III study.

PubMed

Zeng, Meng-Su; Ye, Hui-Yi; Guo, Liang; Peng, Wei-Jun; Lu, Jian-Ping; Teng, Gao-Jun; Huan, Yi; Li, Ping; Xu, Jian-Rong; Liang, Chang-Hong; Breuer, Josy

2013-12-01

Contrast agents help to improve visibility in magnetic resonance (MR) imaging. However, owing to the large interstitial spaces of the liver, there is a reduction in the natural contrast gradient between lesions and healthy tissue. This study was undertaken to evaluate the efficacy and safety of the liver-specific MR imaging contrast agent gadoxetate disodium (Gd-EOB-DTPA) in Chinese patients. This was a single-arm, open-label, multicenter study in patients with known or suspected focal liver lesions referred for contrast-enhanced MR imaging. MR imaging was performed in 234 patients before and after a single intravenous bolus of Gd-EOB-DTPA (0.025 mmol/kg body weight). Images were evaluated by clinical study investigators and three independent, blinded radiologists. The primary efficacy endpoint was sensitivity in lesion detection. Gd-EOB-DTPA improved sensitivity in lesion detection by 9.46% compared with pre-contrast imaging for the average of the three blinded readers (94.78% vs 85.32% for Gd-EOB-DTPA vs pre-contrast, respectively). Improvements in detection were more pronounced in lesions less than 1 cm. Gd-EOB-DTPA improved diagnostic accuracy in lesion classification. This open-label study demonstrated that Gd-EOB-DTPA improves diagnostic sensitivity in liver lesions, particularly in those smaller than 1 cm. Gd-EOB-DTPA also significantly improves the diagnostic accuracy in lesion classification, and furthermore, Gd-EOB-DTPA is safe in Chinese patients with liver lesions.

Primed infusion with delayed equilibrium of Gd.DTPA for enhanced imaging of small pulmonary metastases.

PubMed

Kalber, Tammy L; Campbell-Washburn, Adrienne E; Siow, Bernard M; Sage, Elizabeth; Price, Anthony N; Ordidge, Katherine L; Walker-Samuel, Simon; Janes, Sam M; Lythgoe, Mark F

2013-01-01

To use primed infusions of the magnetic resonance imaging (MRI) contrast agent Gd.DTPA (Magnevist), to achieve an equilibrium between blood and tissue (eqMRI). This may increase tumor Gd concentrations as a novel cancer imaging methodology for the enhancement of small tumor nodules within the low signal-to-noise background of the lung. A primed infusion with a delay before equilibrium (eqMRI) of the Gd(III) chelator Gd.DTPA, via the intraperitoneal route, was used to evaluate gadolinium tumor enhancement as a function of a bolus injection, which is applied routinely in the clinic, compared to gadolinium maintained at equilibrium. A double gated (respiration and cardiac) spin-echo sequence at 9.4T was used to evaluate whole lungs pre contrast and then at 15 (representative of bolus enhancement), 25 and 35 minutes (representative of eqMRI). This was carried out in two lung metastasis models representative of high and low tumor cell seeding. Lungs containing discrete tumor nodes where inflation fixed and taken for haematoxylin and eosin staining as well as CD34 staining for correlation to MRI. We demonstrate that sustained Gd enhancement, afforded by Gd equilibrium, increases the detection of pulmonary metastases compared to bolus enhancement and those tumors which enhance at equilibrium are sub-millimetre in size (<0.7 mm(2)) with a similar morphology to early bronchoalveolar cell carcinomas. As Gd-chelates are routinely used in the clinic for detecting tumors by MRI, this methodology is readily transferable to the clinic and advances MRI as a methodology for the detection of small pulmonary tumors.

Gadolinium Enhanced MR Coronary Vessel Wall Imaging at 3.0 Tesla.

PubMed

Kelle, Sebastian; Schlendorf, Kelly; Hirsch, Glenn A; Gerstenblith, Gary; Fleck, Eckart; Weiss, Robert G; Stuber, Matthias

2010-10-11

Purpose. We evaluated the influence of the time between low-dose gadolinium (Gd) contrast administration and coronary vessel wall enhancement (LGE) detected by 3T magnetic resonance imaging (MRI) in healthy subjects and patients with coronary artery disease (CAD). Materials and Methods. Four healthy subjects (4 men, mean age 29 ± 3 years and eleven CAD patients (6 women, mean age 61 ± 10 years) were studied on a commercial 3.0 Tesla (T) whole-body MR imaging system (Achieva 3.0 T; Philips, Best, The Netherlands). T1-weighted inversion-recovery coronary magnetic resonance imaging (MRI) was repeated up to 75 minutes after administration of low-dose Gadolinium (Gd) (0.1 mmol/kg Gd-DTPA). Results. LGE was seen in none of the healthy subjects, however in all of the CAD patients. In CAD patients, fifty-six of 62 (90.3%) segments showed LGE of the coronary artery vessel wall at time-interval 1 after contrast. At time-interval 2, 34 of 42 (81.0%) and at time-interval 3, 29 of 39 evaluable segments (74.4%) were enhanced. Conclusion. In this work, we demonstrate LGE of the coronary artery vessel wall using 3.0 T MRI after a single, low-dose Gd contrast injection in CAD patients but not in healthy subjects. In the majority of the evaluated coronary segments in CAD patients, LGE of the coronary vessel wall was already detectable 30-45 minutes after administration of the contrast agent.

Accumulation of MRI contrast agents in malignant fibrous histiocytoma for gadolinium neutron capture therapy.

PubMed

Fujimoto, T; Ichikawa, H; Akisue, T; Fujita, I; Kishimoto, K; Hara, H; Imabori, M; Kawamitsu, H; Sharma, P; Brown, S C; Moudgil, B M; Fujii, M; Yamamoto, T; Kurosaka, M; Fukumori, Y

2009-07-01

Neutron-capture therapy with gadolinium (Gd-NCT) has therapeutic potential, especially that gadolinium is generally used as a contrast medium in magnetic resonance imaging (MRI). The accumulation of gadolinium in a human sarcoma cell line, malignant fibrosis histiocytoma (MFH) Nara-H, was visualized by the MRI system. The commercially available MRI contrast medium Gd-DTPA (Magnevist, dimeglumine gadopentetate aqueous solution) and the biodegradable and highly gadopentetic acid (Gd-DTPA)-loaded chitosan nanoparticles (Gd-nanoCPs) were prepared as MRI contrast agents. The MFH cells were cultured and collected into three falcon tubes that were set into the 3-tesra MRI system to acquire signal intensities from each pellet by the spin echo method, and the longitudinal relaxation time (T1) was calculated. The amount of Gd in the sample was measured by inductively coupled plasma atomic emission spectrography (ICP-AES). The accumulation of gadolinium in cells treated with Gd-nanoCPs was larger than that in cells treated with Gd-DTPA. In contrast, and compared with the control, Gd-DTPA was more effective than Gd-nanoCPs in reducing T1, suggesting that the larger accumulation exerted the adverse effect of lowering the enhancement of MRI. Further studies are warranted to gain insight into the therapeutic potential of Gd-NCT.

Comparison of triple dose versus standard dose gadolinium-DTPA for detection of MRI enhancing lesions in patients with primary progressive multiple sclerosis.

PubMed Central

Filippi, M; Campi, A; Martinelli, V; Colombo, B; Yousry, T; Canal, N; Scotti, G; Comi, G

1995-01-01

This study was performed to evaluate whether a triple dose of gadolinium-DTPA (Gd-DTPA) increases the sensitivity of brain MRI for detecting enhancing lesions in patients with primary progressive multiple sclerosis (PPMS). T1 weighted brain MRI was obtained for 10 patients with PPMS in two sessions. In the first session, one scan was obtained five to seven minutes after the injection of 0.1 mmol/kg Gd-DTPA (standard dose). In the second session, six to 24 hours later, one scan before and two scans five to seven minutes and one hour after the injection of 0.3 mmol/kg Gd-DTPA (triple dose) were obtained. Four enhancing lesions were detected in two patients when the standard dose of Gd-DTPA was used. The numbers of enhancing lesions increased to 13 and the numbers of patients with such lesions to five when the triple dose of Gd-DTPA was used and to 14 and six in the one hour delayed scans. The mean contrast ratio for enhancing lesions detected with the triple dose of Gd-DTPA was higher than those for lesions present in both the standard dose (P < 0.0009) and the one hour delayed scans (P = 0.04). These data indicate that with a triple dose of Gd-DTPA many more enhancing lesions can be detected in patients with PPMS. This is important both for planning clinical trials and for detecting the presence of inflammation in vivo in the lesions of such patients. Images PMID:8530944

Gadolinium-Loaded Solid Lipid Nanoparticles as a Tumor-Absorbable Contrast Agent for Early Diagnosis of Colorectal Tumors Using Magnetic Resonance Colonography.

PubMed

Sun, Jihong; Zhang, Shizheng; Jiang, Shaojie; Bai, Weixian; Liu, Fei; Yuan, Hong; Ji, Jiansong; Luo, Jingfeng; Han, Guocan; Chen, Lumin; Jin, Yin; Hu, Peng; Yu, Lei; Yang, Xiaoming

2016-09-01

Magnetic resonance (MR) contrast agents focusing on special functions are required to improve cancer diagnosis, particularly in the early stages. Here, we designed multifunctional solid lipid nanoparticles (SLNs) with simultaneous loading of gadolinium (Gd) diethylenetriaminepentaacetic acid (Gd-DTPA) and octadecylamine fluorescein isothiocyanate (FITC) to obtain Gd-FITC-SLNs as a tumor-absorbable nanoparticle contrast agent for the histological confirmation of MR imaging (MRI) findings. Colorectal tumors were evaluated in vitro and in vivo via direct uptake of this contrast agent, which displayed reasonable T1 relaxivity and no significant cytotoxicity at the experimental concentrations in human colon carcinoma cells (HT29) and mouse colon carcinoma cells (CT26). In vitro cell uptake experiments demonstrated that contrast agent absorption by the two types of cancer cells was concentration-dependent in the safe concentration range. During in vivo MRI, transrectal infusion of Gd-FITC-SLNs showed more significant enhancement at the tumor site compared with the infusion of Gd-DTPA in female C57/BL mice with azoxymethane/dextran sulfate sodium-induced colorectal highgrade intraepithelial neoplasia. Subsequent confocal fluorescence microscopy demonstrated Gd-FITC-SLNs as highly concentrated green fluorescent spots distributed from the tumor capsule into the tumor. This study establishes the "proof-of-principle" of a new MRI technique wherein colorectal tumors are enhanced via direct absorption or uptake of the nanoparticle contrast agent.

Gadolinium released by the linear gadolinium-based contrast-agent Gd-DTPA decreases the activity of human epithelial Na+ channels (ENaCs).

PubMed

Knoepp, Fenja; Bettmer, Joerg; Fronius, Martin

2017-05-01

Gadolinium-based-contrast-agents (GBCAs) are used for magnetic-resonance-imaging and associated with renal and cardiovascular adverse reactions caused by released Gd 3+ ions. Gd 3+ is also a modulator of mechano-gated ion channels, including the epithelial Na + channel (ENaC) that is expressed in kidney epithelium and the vasculature. ENaC is important for salt-/water homeostasis and blood pressure regulation and a likely target of released Gd 3+ from GBCAs causing the above-mentioned adverse reactions. Therefore this study examined the effect of Gd 3+ and GBCAs on ENaC's activity. Human αβγENaC was expressed in Xenopus laevis oocytes and exposed to Gd 3+ , linear (Gd-DTPA, Magnevist) or cyclic (Dotarem) GBCAs. Transmembrane ion-currents (I M ) were recorded by the two-electrode-voltage-clamp technique and Gd 3+ -release by Gd-DTPA was confirmed by inductively coupled plasma-mass spectrometry. Gd 3+ exerts biphasic effects on ENaC's activity: ≤0.3mmol/l decreased I M which was preventable by DEPC (modifies histidines). Strikingly Gd 3+ ≥0.4mmol/l increased I M and this effect was prevented by cysteine-modifying MTSEA. Linear Gd-DTPA and Magnevist mimicked the effect of ≤0.3mmol/l Gd 3+ , whereas the chelator DTPA showed no effect. Gd 3+ and Gd-DTPA increased the IC 50 for amiloride, but did not affect ENaC's self-inhibition. Interestingly, cyclic Gd-DOTA (Dotarem) increased I M to a similar extent as its chelator DOTA, suggesting that the chelator rather than released Gd 3+ is responsible for this effect. These results confirm Gd 3+ -release from linear Gd-DTPA and indicate that the released Gd 3+ amount is sufficient to interfere with ENaC's activity to provide putative explanations for GBCA-related adverse effects. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluation of Focal Liver Reaction after Proton Beam Therapy for Hepatocellular Carcinoma Examined Using Gd-EOB-DTPA Enhanced Hepatic Magnetic Resonance Imaging.

PubMed

Takamatsu, Shigeyuki; Yamamoto, Kazutaka; Maeda, Yoshikazu; Kawamura, Mariko; Shibata, Satoshi; Sato, Yoshitaka; Terashima, Kazuki; Shimizu, Yasuhiro; Tameshige, Yuji; Sasaki, Makoto; Asahi, Satoko; Kondou, Tamaki; Kobayashi, Satoshi; Matsui, Osamu; Gabata, Toshifumi

2016-01-01

Proton beam therapy (PBT) achieves good local control for hepatocellular carcinoma (HCC), and toxicity tends to be lower than for photon radiotherapy. Focal liver parenchymal damage in radiotherapy is described as the focal liver reaction (FLR); the threshold doses (TDs) for FLR in the background liver have been analyzed in stereotactic ablative body radiotherapy and brachytherapy. To develop a safer approach for PBT, both TD and liver volume changes are considered clinically important in predicting the extent of damage before treatment, and subsequently in reducing background liver damage. We investigated appearance time, TDs and volume changes regarding FLR after PBT for HCC. Patients who were treated using PBT and were followed up using gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (Gd-EOB-DTPA MRI) after PBT were enrolled. Sixty-eight lesions in 58 patients were eligible for analysis. MRI was acquired at the end of treatment, and at 1, 2, 3 and 6 months after PBT. We defined the FLR as a clearly depicted hypointense area on the hepatobiliary phase of Gd-EOB-DTPA MRI, and we monitored TDs and volume changes in the FLR area and the residual liver outside of the FLR area. FLR was depicted in all lesions at 3 months after PBT. In FLR expressed as the 2-Gy equivalent dose (α/β = 3 Gy), TDs did not differ significantly (27.0±6.4 CGE [10 fractions [Fr] vs. 30.5±7.3 CGE [20 Fr]). There were also no correlations between the TDs and clinical factors, and no significant differences between Child-Pugh A and B scores. The volume of the FLR area decreased and the residual liver volume increased, particularly during the initial 3 months. This study established the FLR dose for liver with HCC, which might be useful in the prediction of remnant liver volume for PBT.

Effects of the magnetic resonance imaging contrast agent Gd-DTPA on plant growth and root imaging in rice.

PubMed

Liu, Zan; Qian, Junchao; Liu, Binmei; Wang, Qi; Ni, Xiaoyu; Dong, Yaling; Zhong, Kai; Wu, Yuejin

2014-01-01

Although paramagnetic contrast agents have a wide range of applications in medical studies involving magnetic resonance imaging (MRI), these agents are seldom used to enhance MRI images of plant root systems. To extend the application of MRI contrast agents to plant research and to develop related techniques to study root systems, we examined the applicability of the MRI contrast agent Gd-DTPA to the imaging of rice roots. Specifically, we examined the biological effects of various concentrations of Gd-DTPA on rice growth and MRI images. Analysis of electrical conductivity and plant height demonstrated that 5 mmol Gd-DTPA had little impact on rice in the short-term. The results of signal intensity and spin-lattice relaxation time (T1) analysis suggested that 5 mmol Gd-DTPA was the appropriate concentration for enhancing MRI signals. In addition, examination of the long-term effects of Gd-DTPA on plant height showed that levels of this compound up to 5 mmol had little impact on rice growth and (to some extent) increased the biomass of rice.

Primed Infusion with Delayed Equilibrium of Gd.DTPA for Enhanced Imaging of Small Pulmonary Metastases

PubMed Central

Kalber, Tammy L.; Campbell-Washburn, Adrienne E.; Siow, Bernard M.; Sage, Elizabeth; Price, Anthony N.; Ordidge, Katherine L.; Walker-Samuel, Simon

2013-01-01

Objectives To use primed infusions of the magnetic resonance imaging (MRI) contrast agent Gd.DTPA (Magnevist), to achieve an equilibrium between blood and tissue (eqMRI). This may increase tumor Gd concentrations as a novel cancer imaging methodology for the enhancement of small tumor nodules within the low signal-to-noise background of the lung. Methods A primed infusion with a delay before equilibrium (eqMRI) of the Gd(III) chelator Gd.DTPA, via the intraperitoneal route, was used to evaluate gadolinium tumor enhancement as a function of a bolus injection, which is applied routinely in the clinic, compared to gadolinium maintained at equilibrium. A double gated (respiration and cardiac) spin-echo sequence at 9.4T was used to evaluate whole lungs pre contrast and then at 15 (representative of bolus enhancement), 25 and 35 minutes (representative of eqMRI). This was carried out in two lung metastasis models representative of high and low tumor cell seeding. Lungs containing discrete tumor nodes where inflation fixed and taken for haematoxylin and eosin staining as well as CD34 staining for correlation to MRI. Results We demonstrate that sustained Gd enhancement, afforded by Gd equilibrium, increases the detection of pulmonary metastases compared to bolus enhancement and those tumors which enhance at equilibrium are sub-millimetre in size (<0.7 mm2) with a similar morphology to early bronchoalveolar cell carcinomas. Conclusion As Gd-chelates are routinely used in the clinic for detecting tumors by MRI, this methodology is readily transferable to the clinic and advances MRI as a methodology for the detection of small pulmonary tumors. PMID:23382996

Do we need gadolinium-based contrast medium for brain magnetic resonance imaging in children?

PubMed

Dünger, Dennis; Krause, Matthias; Gräfe, Daniel; Merkenschlager, Andreas; Roth, Christian; Sorge, Ina

2018-06-01

Brain imaging is the most common examination in pediatric magnetic resonance imaging (MRI), often combined with the use of a gadolinium-based contrast medium. The application of gadolinium-based contrast medium poses some risk. There is limited evidence of the benefits of contrast medium in pediatric brain imaging. To assess the diagnostic gain of contrast-enhanced sequences in brain MRI when the unenhanced sequences are normal. We retrospectively assessed 6,683 brain MR examinations using contrast medium in children younger than 16 years in the pediatric radiology department of the University Hospital Leipzig to determine whether contrast-enhanced sequences delivered additional, clinically relevant information to pre-contrast sequences. All examinations were executed using a 1.5-T or a 3-T system. In 8 of 3,003 (95% confidence interval 0.12-0.52%) unenhanced normal brain examinations, a relevant additional finding was detected when contrast medium was administered. Contrast enhancement led to a change in diagnosis in only one of these cases. Children with a normal pre-contrast brain MRI rarely benefit from contrast medium application. Comparing these results to the risks and disadvantages of a routine gadolinium application, there is substantiated numerical evidence for avoiding routine administration of gadolinium in a pre-contrast normal MRI examination.

[Gadolinium-based contrast agents for magnetic resonance imaging].

PubMed

Carrasco Muñoz, S; Calles Blanco, C; Marcin, Javier; Fernández Álvarez, C; Lafuente Martínez, J

2014-06-01

Gadolinium-based contrast agents are increasingly being used in magnetic resonance imaging. These agents can improve the contrast in images and provide information about function and metabolism, increasing both sensitivity and specificity. We describe the gadolinium-based contrast agents that have been approved for clinical use, detailing their main characteristics based on their chemical structure, stability, and safety. In general terms, these compounds are safe. Nevertheless, adverse reactions, the possibility of nephrotoxicity from these compounds, and the possibility of developing nephrogenic systemic fibrosis will be covered in this article. Lastly, the article will discuss the current guidelines, recommendations, and contraindications for their clinical use, including the management of pregnant and breast-feeding patients. Copyright © 2014 SERAM. Published by Elsevier Espana. All rights reserved.

Magnetic resonance imaging of the nose and paranasal sinuses.

PubMed Central

Lloyd, G A

1989-01-01

Seventy-five patients with a wide range of sinus disease have been investigated by magnetic resonance (MR): these included congenital conditions, allergic and inflammatory sinus disease, fungus infections, and the necrotizing granulomata. In addition, a variety of benign and malignant tumours have been examined, and in the more recent sinus malignancies the paramagnetic contrast agent, Gadolinium (Gd) DTPA (Schering Health Care) has been used. This experience of magnetic resonance scanning has shown that it is superior to computed tomography in demonstrating the extent of malignant disease in the nose and sinuses; most especially when Gd DTPA is used, reaching an accuracy of over 96% by biopsy correlation. An additional advantage of this technique is the wide coverage of the head and neck for the assessment of malignant disease, provided by direct 3 plane imaging and the multislice facility. The main disadvantage of magnetic resonance of the sinuses is the poor demonstration of calcification and bone. For this reason the MR scans may need to be augmented by high resolution CT performed specifically to show bone detail. Images Figure 2. Figure 3. PMID:2926770

Brain Delivery of Drug and MRI Contrast Agent: Detection and Quantitative Determination of Brain Deposition of CPT-Glu Using LC-MS/MS and Gd-DTPA Using Magnetic Resonance Imaging.

PubMed

Tabanor, Kayann; Lee, Phil; Kiptoo, Paul; Choi, In-Young; Sherry, Erica B; Eagle, Cheyenne Sun; Williams, Todd D; Siahaan, Teruna J

2016-02-01

Successful treatment and diagnosis of neurological diseases depend on reliable delivery of molecules across the blood-brain barrier (BBB), which restricts penetration of pharmaceutical drugs and diagnostic agents into the brain. Thus, developing new noninvasive strategies to improve drug delivery across the BBB is critically needed. This study was aimed at evaluating the activity of HAV6 peptide (Ac-SHAVSS-NH2) in improving brain delivery of camptothecin-glutamate (CPT-Glu) conjugate and gadolinium-diethylenetriaminepentaacetate (Gd-DTPA) contrast agent in Sprague-Dawley rats. Brain delivery of both CPT-Glu and Gd-DTPA was evaluated in an in situ rat brain perfusion model in the presence and absence of HAV6 peptide (1.0 mM). Gd-DTPA (0.6 mmol/kg) was intravenously (iv) administered with and without HAV6 peptide (0.019 mmol/kg) in rats. The detection and quantification of CPT-Glu and Gd-DTPA in the brain were carried out by LC-MS/MS and quantitative magnetic resonance imaging (MRI), respectively. Rats perfused with CPT-Glu in combination with HAV6 had significantly higher deposition of drug in the brain compared to CPT-Glu alone. MRI results also showed that administration of Gd-DTPA in the presence of HAV6 peptide led to significant accumulation of Gd-DTPA in various regions of the brain in both the in situ rat brain perfusion and in vivo studies. All observations taken together indicate that HAV6 peptide can disrupt the BBB and enhance delivery of small molecules into the brain.

Brain Delivery of Drug and MRI Contrast Agent: Detection and Quantitative Determination of Brain Deposition of CPT-Glu Using LC-MS/MS and Gd-DTPA Using Magnetic Resonance Imaging

PubMed Central

Tabanor, Kayann; Lee, Phil; Kiptoo, Paul; Choi, In-Young; Sherry, Erica B.; Eagle, Cheyenne Sun; Williams, Todd D.; Siahaan, Teruna J.

2015-01-01

Successful treatment and diagnosis of neurological diseases depend on reliable delivery of molecules across the blood-brain barrier (BBB), which restricts penetration of pharmaceutical drugs and diagnostic agents into the brain. Thus, developing new non-invasive strategies to improve drug delivery across the BBB is critically needed. This study was aimed at evaluating the activity of HAV6 peptide (Ac-SHAVSS-NH2) in improving brain delivery of camptothecin-glutamate (CPT-Glu) conjugate and gadolinium-diethylenetriaminepentaacetate (Gd-DTPA) contrast agent in Sprague-Dawley rats. Brain delivery of both CPT-Glu and Gd-DTPA was evaluated in an in situ rat brain perfusion model in the presence and absence of HAV6 peptide (1.0 mM). Gd-DTPA (0.6 mmol/kg) was intravenously (i.v.) administered with and without HAV6 peptide (0.019 mmol/kg) in rats. The detection and quantification of CPT-Glu and Gd-DTPA in the brain were carried out by LC-MS/MS and quantitative magnetic resonance imaging (MRI), respectively. Rats perfused with CPT-Glu in combination with HAV6 had significantly higher deposition of drug in the brain compared to CPT-Glu alone. MRI results also showed that administration of Gd-DTPA in the presence of HAV6 peptide led to significant accumulation of Gd-DTPA in various regions of the brain in both the in situ rat brain perfusion and in vivo studies. All observations taken together indicate that HAV6 peptide can disrupt the BBB and enhance delivery of small molecules into the brain. PMID:26705088

Radiologic Diagnosis of Spondylodiscitis, Role of Magnetic Resonance.

PubMed

Ramadani, Naser; Dedushi, Kreshnike; Kabashi, Serbeze; Mucaj, Sefedin

2017-03-01

Study aim is to report the Magnetic Resonance Imaging (MRI) features of acute and chronic spontaneous spondylodiscitis. 57 year old female, complaining of a fever and longstanding cervical pain worsened during physical therapy. MR images were acquired using superconductive magnet 1.5 T, with the following sequences: sagittal PD and T2 TSE, sagittal T1 SE, axial PD and T2 TSE (lumbar spine), axial T2 GRE (cervical spine). Axial and sagittal T1 SE after administration of (gadolinium DTPA). Examination was reviewed by three radiologists and compared to CT findings. Patient reported cervical pain associated with fever and minimal weight loss. Blood tests were normal except hyperglycemia (DM tip II). X Ray: vertebral destruction localized at C-4 and C-5: NECT: destruction of the C-4/C-5 vertebral bodies (ventral part). MRI: Low signal of the bone marrow on T1l images, which enhanced after Gd-DTPA administration and became intermediate or high on T2 images. The steady high signal intensity of the disk on T2 images and enhancement on T1 images is typical for an acute inflammatory process. Bone Scintigrafi results: Bone changes suspicious for metastasis. Whole body CT results: apart from spine, no other significant changes. MRI is the most sensitive technique for the diagnosis of spondylodiscitis in the acute phase and comparable to CT regarding chronial stage of the disease. The present imagining essay os aimed at showing the main magnetic resonance imaging findings of tuberculous discitis.

Radiologic Diagnosis of Spondylodiscitis, Role of Magnetic Resonance

PubMed Central

Ramadani, Naser; Dedushi, Kreshnike; Kabashi, Serbeze; Mucaj, Sefedin

2017-01-01

Introduction: Study aim is to report the Magnetic Resonance Imaging (MRI) features of acute and chronic spontaneous spondylodiscitis. Case report: 57 year old female, complaining of a fever and longstanding cervical pain worsened during physical therapy. Methods: MR images were acquired using superconductive magnet 1.5 T, with the following sequences: sagittal PD and T2 TSE, sagittal T1 SE, axial PD and T2 TSE (lumbar spine), axial T2 GRE (cervical spine). Axial and sagittal T1 SE after administration of (gadolinium DTPA). Examination was reviewed by three radiologists and compared to CT findings. Results: Patient reported cervical pain associated with fever and minimal weight loss. Blood tests were normal except hyperglycemia (DM tip II). X Ray: vertebral destruction localized at C-4 and C-5: NECT: destruction of the C-4/C-5 vertebral bodies (ventral part). MRI: Low signal of the bone marrow on T1l images, which enhanced after Gd-DTPA administration and became intermediate or high on T2 images. The steady high signal intensity of the disk on T2 images and enhancement on T1 images is typical for an acute inflammatory process. Bone Scintigrafi results: Bone changes suspicious for metastasis. Whole body CT results: apart from spine, no other significant changes. Conclusion: MRI is the most sensitive technique for the diagnosis of spondylodiscitis in the acute phase and comparable to CT regarding chronial stage of the disease. The present imagining essay os aimed at showing the main magnetic resonance imaging findings of tuberculous discitis. PMID:28484299

Optimal gadolinium dose level for magnetic resonance imaging (MRI) contrast enhancement of U87-derived tumors in athymic nude rats for the assessment of photodynamic therapy

NASA Astrophysics Data System (ADS)

Cross, Nathan; Varghai, Davood; Flask, Chris A.; Feyes, Denise K.; Oleinick, Nancy L.; Dean, David

2009-02-01

This study aims to determine the effect of varying gadopentetate dimeglumine (Gd-DTPA) dose on Dynamic Contrast Enhanced-Magnetic Resonance Imaging (DCE-MRI) tracking of brain tumor photodynamic therapy (PDT) outcome. Methods: We injected 2.5 x 105 U87 cells (derived from human malignant glioma) into the brains of six athymic nude rats. After 9, 12, and 13 days DCE-MRI images were acquired on a 9.4 T micro-MRI scanner before and after administration of 100, 150, or 200 μL of Gd-DTPA. Results: Tumor region normalized DCE-MRI scan enhancement at peak was: 1.217 over baseline (0.018 Standard Error [SE]) at the 100 μL dose, 1.339 (0.013 SE) at the 150 μL dose, and 1.287 (0.014 SE) at the 200 μL dose. DCE-MRI peak tumor enhancement at the 150 μL dose was significantly greater than both the 100 μL dose (p < 3.323E-08) and 200 μL dose (p < 0.0007396). Discussion: In this preliminary study, the 150 μL Gd-DTPA dose provided the greatest T1 weighted contrast enhancement, while minimizing negative T2* effects, in DCE-MRI scans of U87-derived tumors. Maximizing Gd-DTPA enhancement in DCE-MRI scans may assist development of a clinically robust (i.e., unambiguous) technique for PDT outcome assessment.

Three-dimensional imaging of the aortic vessel wall using an elastin-specific magnetic resonance contrast agent.

PubMed

Makowski, Marcus R; Preissel, Anne; von Bary, Christian; Warley, Alice; Schachoff, Sylvia; Keithan, Alexandra; Cesati, Richard R; Onthank, David C; Schwaiger, Markus; Robinson, Simon P; Botnar, René M

2012-07-01

The aim of this study was to demonstrate the feasibility of high-resolution 3-dimensional aortic vessel wall imaging using a novel elastin-specific magnetic resonance contrast agent (ESMA) in a large animal model. The thoracic aortic vessel wall of 6 Landrace pigs was imaged using a novel ESMA and a nonspecific control agent. On day 1, imaging was performed before and after the administration of a nonspecific control agent, gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA; Bayer Schering AG, Berlin, Germany). On day 3, identical scans were repeated before and after the administration of a novel ESMA (Lantheus Medical Imaging, North Billerica, Massachusetts). Three-dimensional inversion recovery gradient echo delayed-enhancement imaging and magnetic resonance (MR) angiography of the thoracic aortic vessel wall were performed on a 1.5-T MR scanner (Achieva; Philips Medical Systems, the Netherlands). The signal-to-noise ratio and the contrast-to-noise ratio of arterial wall enhancement, including the time course of enhancement, were assessed for ESMA and Gd-DTPA. After the completion of imaging sessions, histology, electron microscopy, and inductively coupled plasma mass spectroscopy were performed to localize and quantify the gadolinium bound to the arterial vessel wall. Administration of ESMA resulted in a strong enhancement of the aortic vessel wall on delayed-enhancement imaging, whereas no significant enhancement could be measured with Gd-DTPA. Ninety to 100 minutes after the administration of ESMA, significantly higher signal-to-noise ratio and contrast-to-noise ratio could be measured compared with the administration of Gd-DTPA (45.7 ± 9.6 vs 13.2 ± 3.5, P < 0.05 and 41.9 ± 9.1 vs 5.2 ± 2.0, P < 0.05). A significant correlation (0.96; P < 0.01) between area measurements derived from ESMA scans and aortic MR angiography scans could be found. Electron microscopy and inductively coupled plasma mass spectroscopy confirmed the colocalization of ESMA with

Triple dose of gadolinium-DTPA and delayed MRI in patients with benign multiple sclerosis.

PubMed Central

Filippi, M; Capra, R; Campi, A; Colombo, B; Prandini, F; Marcianò, N; Gasparotti, R; Comi, G

1996-01-01

OBJECTIVES--To evaluate whether a triple dose of gadolinium-DTPA (Gd-DTPA) or delayed MRI increase the number, size, and conspicuousness of enhancing lesions in patients with benign multiple sclerosis. METHODS--T1 weighted brain MRI was carried out on 20 patients with benign multiple sclerosis (expanded disability status scale < 3 with a disease duration > 10 years) in two sessions. In the first session, one scan was obtained before and two scans five to seven minutes and 20-30 minutes after the injection of 0.1 mmol/kg Gd-DTPA (standard dose). In the second session, six to 24 hours later, the same procedure was repeated with 0.3 mmol/kg Gd-DTPA (triple dose). RESULTS--Nine enhancing lesions were found in seven patients (35%) using the standard dose of Gd-DTPA. The numbers of enhancing lesions increased to 13 (P = 0.03) and the number of patients with such lesions to eight (40%) on the delayed standard dose scans. On the early triple dose scans, we found 19 enhancing lesions in 10 patients (50%). The number of enhancing lesions was significantly higher (P = 0.01) than that obtained with the early standard dose. The number of enhancing lesions was 18 and the number of "active" patients 11 (55%) on the delayed triple dose scans. The enhancing areas increased progressively from the early standard dose scans to the delayed triple dose scans. The contrast ratios of the lesions detected in early standard dose scans was lower than those of lesions present in the early (P = 0.01) and delayed (P = 0.04) triple dose scans. CONCLUSIONS--More enhancing lesions were detected in patients with benign multiple sclerosis with both delay of MRI and the use of triple dose of Gd-DTPA suggesting that the amount of inflammation in the lesions of such patients is mild and heterogeneous. Images PMID:8778257

Contrast-enhanced magnetic resonance angiography: first-pass arterial enhancement as a function of gadolinium-chelate concentration, and the saline chaser volume and injection rate.

PubMed

Husarik, Daniela B; Bashir, Mustafa R; Weber, Paul W; Nichols, Eli B; Howle, Laurens E; Merkle, Elmar M; Nelson, Rendon C

2012-02-01

To evaluate the effect of the contrast medium (CM) concentration and the saline chaser volume and injection rate on first-pass aortic enhancement characteristics in contrast-enhanced magnetic resonance angiography using a physiologic flow phantom. Imaging was performed on a 3.0-T magnetic resonance system (MAGNETOM Trio, Siemens Healthcare Solutions, Inc, Erlangen, Germany) using a 2-dimensional fast low angle shot T1-weighted sequence (repetition time, 500 milliseconds; echo time, 1.23 milliseconds; flip angle, 8 degrees; 1 frame/s × 60 seconds). The following CM concentrations injected at 2 mL/s were used with 3 different contrast agents (gadolinium [Gd]-BOPTA, Gd-HP-DO3A, Gd-DTPA): 20 mL of undiluted CM (100%) and 80%, 40%, 20%, 10%, 5%, and 2.5% of the full amount, all diluted in saline to a volume of 20 mL to ensure equal bolus volume. The CM was followed by saline chasers of 20 to 60 mL injected at 2 mL/s and 6 mL/s. Aortic signal intensity (SI) was measured, and normalized SI versus time (SI/Tn) curves were generated. The maximal SI (SI(max)), bolus length, and areas under the SI/Tn curve were calculated. Decreasing the CM concentration from 100% to 40% resulted in a decrease of SI(max) to 86.1% (mean). Further decreasing the CM concentration to 2.5% decreased SI(max) to 5.1% (mean). Altering the saline chaser volume had no significant effect on SI(max). Increasing the saline chaser injection rate had little effect (mean increase, 2.2%) on SI(max) when using ≥40% of CM. There was a larger effect (mean increase, 19.6%) when ≤20% of CM were used. Bolus time length was significantly shorter (P < 0.001), and area under the SI/T(n) curve was significantly smaller (P < 0.01) for the CM protocols followed by a saline chaser injected at 6 mL/s compared with a saline chaser injected at 2 mL/s. With 40% of CM and a fast saline chaser, SImax close to that with undiluted CM can be achieved. An increased saline chaser injection rate has a more pronounced effect on

Diagnostic value of three-dimensional magnetic resonance imaging of inner ear after intratympanic gadolinium injection, and clinical application of magnetic resonance imaging scoring system in patients with delayed endolymphatic hydrops.

PubMed

Gu, X; Fang, Z-M; Liu, Y; Lin, S-L; Han, B; Zhang, R; Chen, X

2014-01-01

Three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging of the inner ear after intratympanic injection of gadolinium, together with magnetic resonance imaging scoring of the perilymphatic space, were used to investigate the positive identification rate of hydrops and determine the technique's diagnostic value for delayed endolymphatic hydrops. Twenty-five patients with delayed endolymphatic hydrops underwent pure tone audiometry, bithermal caloric testing, vestibular-evoked myogenic potential testing and three-dimensional magnetic resonance imaging of the inner ear after bilateral intratympanic injection of gadolinium. The perilymphatic space of the scanned images was analysed to investigate the positive identification rate of endolymphatic hydrops. According to the magnetic resonance imaging scoring of the perilymphatic space and the diagnostic standard, 84 per cent of the patients examined had endolymphatic hydrops. In comparison, the positive identification rates for vestibular-evoked myogenic potential and bithermal caloric testing were 52 per cent and 72 per cent respectively. Three-dimensional magnetic resonance imaging after intratympanic injection of gadolinium is valuable in the diagnosis of delayed endolymphatic hydrops and its classification. The perilymphatic space scoring system improved the diagnostic accuracy of magnetic resonance imaging.

Analysis of pharmacokinetics of Gd-DTPA for dynamic contrast-enhanced magnetic resonance imaging.

PubMed

Taheri, Saeid; Shah, N Jon; Rosenberg, Gary A

2016-09-01

The pharmacokinetics (PK) of the contrast agent Gd-DTPA administered intravenously (i.v.) for contrast-enhanced MR imaging (DCE-MRI) is an important factor for quantitative data acquisition. We studied the effect of various initial bolus doses on the PK of Gd-DTPA and analyzed population PK of a lower dose for intra-subject variations in DCE-MRI. First, fifteen subjects (23-85years, M/F) were randomly divided into four groups for DCE-MRI with different Gd-DTPA dose: group-I, 0.1mmol/kg, n=4; group-II, 0.05mmol/kg, n=4; group-III, 0.025mmol/kg, n=4; and group-IV, 0.0125mmol/kg, n=3. Sequential fast T1 mapping sequence, after a bolus i.v. Gd-DTPA administered, and a linear T1-[Gd-DTPA] relationship were used to estimate the PK of Gd-DTPA. Secondly, MR-acquired PKs of Gd-DTPA from 58 subjects (28-80years, M/F) were collected retrospectively, from an ongoing study of the brain using DCE-MRI with Gd-DTPA at 0.025mmol/kg, to statistically analyze population PK of Gd-DTPA. We found that the PK of Gd-DTPA (i.v. 0.025mmol/kg) had a half-life of 37.3±6.6min, and was a better fit into a linear T1-[Gd-DTPA] relationship than higher doses (up to 0.1mmol/kg). The area under the curve (AUC) for 0.025mmol/kg was 3.37±0.46, which was a quarter of AUC of 0.1mmol/kg. In population analysis, a dose of 0.025mmol/kg of Gd-DTPA provided less than 5% subject-dependent variation in the PK of Gd-DTPA. Administration of 0.025mmol/kg Gd-DTPA enabled us to estimate [Gd-DTPA] from T1 by using a linear relationship that has a lower estimation error compared to a non-linear relationship. DCE-MRI with a quarter dose of Gd-DTPA is more sensitive to detect changes in [Gd-DTPA]. Copyright © 2016 Elsevier Inc. All rights reserved.

Comparison of cardiogoniometry and electrocardiography with perfusion cardiac magnetic resonance imaging and late gadolinium enhancement.

PubMed

Birkemeyer, Ralf; Toelg, Ralph; Zeymer, Uwe; Wessely, Rainer; Jäckle, Sebastian; Hairedini, Bajram; Lübke, Mike; Aßfalg, Manfred; Jung, Werner

2012-12-01

Cardiogoniometry (CGM) is a spatio-temporal five-lead resting electrocardiographic method utilizing automated analysis. The purpose of this study was to determine CGM's and electrocardiography (ECG)'s accuracy for detecting myocardial ischaemia and/or lesions in comparison with perfusion cardiac magnetic resonance imaging (CMRI) and late gadolinium enhancement (LGE). Forty (n= 40) patients with suspected or known stable coronary artery disease were examined by CGM and resting ECG directly prior to CMRI including adenosine stress perfusion (ASP) and LGE. The investigators visually reading the CMRI were blinded to the CGM and ECG results. Half of the patients (n= 20) had a normal CMRI while the other half presented with either abnormal ASP and/or detectable LGE. Cardiogoniometry yielded an accuracy of 83% (sensitivity 70%) and ECG of 63% (sensitivity 35%) compared with CMRI. In this pilot study CGM compares more favourably than ECG with the detection of ischaemia and/or structural myocardial lesions on CMRI.

Anti-EpCAM scFv gadolinium chelate: a novel targeted MRI contrast agent for imaging of colorectal cancer.

PubMed

Khantasup, Kannika; Saiviroonporn, Pairash; Jarussophon, Suwatchai; Chantima, Warangkana; Dharakul, Tararaj

2018-05-08

The development of targeted contrast agents for magnetic resonance imaging (MRI) facilitates enhanced cancer imaging and more accurate diagnosis. In the present study, a novel contrast agent was developed by conjugating anti-EpCAM humanized scFv with gadolinium chelate to achieve target specificity. The material design strategy involved site-specific conjugation of the chelating agent to scFv. The scFv monomer was linked to maleimide-DTPA via unpaired cysteine at the scFv C-terminus, followed by chelation with gadolinium (Gd). Successful scFv-DTPA conjugation was achieved at 1:10 molar ratio of scFv to maleimide-DTPA at pH 6.5. The developed anti-EpCAM-Gd-DTPA MRI contrast agent was evaluated for cell targeting ability, in vitro serum stability, cell cytotoxicity, relaxivity, and MR contrast enhancement. A high level of targeting efficacy of anti-EpCAM-Gd-DTPA to an EpCAM-overexpressing HT29 colorectal cell was demonstrated by confocal microscopy. Good stability of the contrast agent was obtained and no cytotoxicity was observed in HT29 cells after 48 h incubation with 25-100 µM of Gd. Favorable imaging was obtained using anti-EpCAM-Gd-DTPA, including 1.8-fold enhanced relaxivity compared with Gd-DTPA, and MR contrast enhancement observed after binding to HT29. The potential benefit of this contrast agent for in vivo MR imaging of colorectal cancer, as well as other EpCAM positive cancers, is suggested and warrants further investigation.

Liver acquisition with acceleration volume acquisition gadolinium-enhanced magnetic resonance combined with T2 sequences in the diagnosis of local recurrence of rectal cancer.

PubMed

Cao, Wuteng; Li, Fangqian; Gong, Jiaying; Liu, Dechao; Deng, Yanhong; Kang, Liang; Zhou, Zhiyang

2016-11-22

To investigate the efficacy of liver acquisition with acceleration volume acquisition (LAVA) gadolinium-enhanced magnetic resonance (MR) sequences and to assess its added accuracy in diagnosing local recurrence (LR) of rectal cancer with conventional T2-weighted fast spin echo (FSE) sequences. Pelvic MRI, including T2-weighted FSE sequences, gadolinium-enhanced sequences of LAVA and T1-weighted FSE with fat suppression, was performed on 225 patients with postoperative rectal cancer. Two readers evaluated the presence of LR according to "T2" (T2 sequences only), "T2 + LAVA-Gad" (LAVA and T2 imaging), and "T2 + T1-fs-Gad" (T1 fat suppression-enhanced sequence with T2 images). To evaluate diagnostic efficiency, imaging quality with LAVA and T1-fs-Gad by subjective scores and the signal intensity (SI) ratio. In the result, the SI ratio of LAVA was significantly higher than that of T1-fs-Gad (p = 0.0001). The diagnostic efficiency of "T2 + LAVA-Gad" was better than that of "T2 + T1-fs-Gad" (p = 0.0016 for Reader 1, p = 0.0001 for Reader 2) and T2 imaging only (p = 0.0001 for Reader 1; p = 0.0001 for Reader 2). Therefore, LAVA gadolinium-enhanced MR increases the accuracy of diagnosis of LR from rectal cancer and could replace conventional T1 gadolinium-enhanced sequences in the postoperative pelvic follow-up of rectal cancer.

Magnetic resonance characteristics and susceptibility weighted imaging of the brain in gadolinium encephalopathy.

PubMed

Samardzic, Dejan; Thamburaj, Krishnamoorthy

2015-01-01

To report the brain imaging features on magnetic resonance imaging (MRI) in inadvertent intrathecal gadolinium administration. A 67-year-old female with gadolinium encephalopathy from inadvertent high dose intrathecal gadolinium administration during an epidural steroid injection was studied with multisequence 3T MRI. T1-weighted imaging shows pseudo-T2 appearance with diffusion of gadolinium into the brain parenchyma, olivary bodies, and membranous labyrinth. Nulling of cerebrospinal fluid (CSF) signal is absent on fluid attenuation recovery (FLAIR). Susceptibility-weighted imaging (SWI) demonstrates features similar to subarachnoid hemorrhage. CT may demonstrate a pseudo-cerebral edema pattern given the high attenuation characteristics of gadolinium. Intrathecal gadolinium demonstrates characteristic imaging features on MRI of the brain and may mimic subarachnoid hemorrhage on susceptibility-weighted imaging. Identifying high dose gadolinium within the CSF spaces on MRI is essential to avoid diagnostic and therapeutic errors. Copyright © 2013 by the American Society of Neuroimaging.

Dynamic Contrast-Enhanced Magnetic Resonance Imaging of the Metastatic Potential of Melanoma Xenografts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ovrebo, Kirsti Marie; Ellingsen, Christine; Galappathi, Kanthi

2012-05-01

Purpose: Gadolinium diethylene-triamine penta-acetic acid (Gd-DTPA)-based dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) has been suggested as a useful noninvasive method for characterizing the physiologic microenvironment of tumors. In the present study, we investigated whether Gd-DTPA-based DCE-MRI has the potential to provide biomarkers for hypoxia-associated metastatic dissemination. Methods and Materials: C-10 and D-12 melanoma xenografts were used as experimental tumor models. Pimonidazole was used as a hypoxia marker. A total of 60 tumors were imaged, and parametric images of K{sup trans} (volume transfer constant of Gd-DTPA) and v{sub e} (fractional distribution volume of Gd-DTPA) were produced by pharmacokinetic analysis of themore » DCE-MRI series. The host mice were killed immediately after DCE-MRI, and the primary tumor and the lungs were resected and prepared for histologic assessment of the fraction of pimonidazole-positive hypoxic tissue and the presence of lung metastases, respectively. Results: Metastases were found in 11 of 26 mice with C-10 tumors and 14 of 34 mice with D-12 tumors. The primary tumors of the metastatic-positive mice had a greater fraction of hypoxic tissue (p = 0.00031, C-10; p < 0.00001, D-12), a lower median K{sup trans} (p = 0.0011, C-10; p < 0.00001, D-12), and a lower median v{sub e} (p = 0.014, C-10; p = 0.016, D-12) than the primary tumors of the metastatic-negative mice. Conclusions: These findings support the clinical attempts to establish DCE-MRI as a method for providing biomarkers for tumor aggressiveness and suggests that primary tumors characterized by low K{sup trans} and low v{sub e} values could have a high probability of hypoxia-associated metastatic spread.« less

T1 mapping combined with Gd-EOB-DTPA-enhanced magnetic resonance imaging in predicting the pathologic grading of hepatocellular carcinoma.

PubMed

Chen, C Y; Chen, J; Xia, C C; Huang, Z X; Song, B

2017-01-01

The aim of this study was to investigate the value of Gd-EOB-DTPA-enhanced MRI on hepatobiliary phase (HBP) imaging and T1 mapping sequence in the differentiation of hepatocellular carcinoma (HCC). A total of 45 patients with HCC who were to undergo a resection were enrolled in this study. Gd-EOB-DTPA-enhanced magnetic resonance examination was performed prior to resection. T1 mapping was performed before and 20 min after injection of Gd-EOB-DTPA. T1 values of the lesions were measured on pre-contrast (T1p) and during HBP (T1-HBP) on T1 maps. The signal intensity, the diameter and the margin of HCC lesions on HBP images were analyzed. The reduction in T1 value (T1d) and the reduction rate (ΔT1%) of T1 mapping between pre-contrast and HBP were calculated. The Edmondson-Steiner classification of each lesion was made after surgery. The SPSS software package was used for statistical analysis and the analysis of receiver operator characteristic (ROC) curve and area under the curve (AUC) were carried out by using MedCalc software package. Mean values of T1p and T1-HBP were 1935.4±730.8 ms and 1257.1±529.1 ms, respectively. T1p accuracy (AUC = 0.685, p = 0.037) in predicting pathological grading was similar to that of T1-HBP (AUC = 0.751, p = 0.005). A T1p of 1648.2 ms or greater had a sensitivity and specificity of 85.19% and 61.11%, respectively. A T1-HBP of 1006 ms or greater had a sensitivity and specificity of 81.84% and 61.11%, respectively. The number of HCCs with a non-smooth tumor margin was 20 (44.4%), and a non-smooth tumor margin correlated moderately with the Edmondson-Steiner grade (Spearman r = 0.491, p = 0.041). There was no significant correlation between T1d, ΔT1%, HCC signal intensity on HBP image and lesion diameter with pathologic grading. T1 mapping in pre-contrast and HBP of Gd-EOB-DTPA-enhanced MRI, a non-smooth tumor margin in the HBP of Gd-EOB-DTPA-enhanced MRI, are useful in predicting the pathologic grading of HCC.

Magnetic Resonance Imaging of Acute Reperfused Myocardial Infarction: Intraindividual Comparison of ECIII-60 and Gd-DTPA in a Swine Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin Jiyang; Teng Gaojun; Feng Yi

2007-04-15

Purpose. To compare a necrosis-avid contrast agent (NACA) bis-Gd-DTPA-pamoic acid derivative (ECIII-60) after intracoronary delivery with an extracellular agent Gd-DTPA after intravenous injection on magnetic resonance imaging (MRI) in a swine model of acute reperfused myocardial infarction (MI). Methods. Eight pigs underwent 90 min of transcatheter coronary balloon occlusion and 60 min of reperfusion. After intravenous injection of Gd-DTPA at a dose of 0.2 mmol/kg, all pigs were scanned with T1-weighted MRI until the delayed enhancement of MI disappeared. Then they were intracoronarily infused with ECIII-60 at 0.0025 mmol/kg and imaged for 5 hr. Signal intensity, infarct-over-normal contrast ratio andmore » relative infarct size were quantified, compared, and correlated with the results of postmortem MRI and triphenyltetrazolium chloride (TTC) histochemical staining. Results. A contrast ratio over 3.0 was induced by both Gd-DTPA and ECIII-60. However, while the delayed enhancement with Gd-DTPA virtually vanished in 1 hr, ECIII-60 at an 80x smaller dose depicted the MI accurately over 5 hr as proven by ex vivo MRI and TTC staining. Conclusion. Both Gd-DTPA and ECIII-60 strongly enhanced acute MI. Comparing with fading contrast in a narrow time window with intravenous Gd-DTPA, intracoronary ECIII-60 persistently demarcated the acute MI, indicating a potential method for postprocedural assessment of myocardial viability after coronary interventions.« less

Phenotypic expression in hypertrophic cardiomyopathy and late gadolinium enhancement on cardiac magnetic resonance.

PubMed

Caetano, Francisca; Botelho, Ana; Trigo, Joana; Silva, Joana; Almeida, Inês; Venâncio, Margarida; Pais, João; Sanches, Conceição; Leitão Marques, António

2014-05-01

The prognostic value of late gadolinium enhancement (LGE) for risk stratification of hypertrophic cardiomyopathy (HCM) patients is the subject of disagreement. We set out to examine the association between clinical and morphological variables, risk factors for sudden cardiac death and LGE in HCM patients. From a population of 78 patients with HCM, we studied 53 who underwent cardiac magnetic resonance. They were divided into two groups according to the presence or absence of LGE. Ventricular arrhythmias and morbidity and mortality during follow-up were analyzed. Patients with LGE were younger at the time of diagnosis (p=0.046) and more often had a family history of sudden death (p=0.008) and known coronary artery disease (p=0.086). On echocardiography they had greater maximum wall thickness (p=0.007) and left atrial area (p=0.037) and volume (p=0.035), and more often presented a restrictive pattern of diastolic dysfunction (p=0.011) with a higher E/É ratio (p=0.003) and left ventricular systolic dysfunction (p=0.038). Cardiac magnetic resonance supported the association between LGE and previous echocardiographic findings: greater left atrial area (p=0.029) and maximum wall thickness (p<0.001) and lower left ventricular ejection fraction (p=0.056). Patients with LGE more often had an implantable cardioverter-defibrillator (ICD) (p=0.015). At follow-up, no differences were found in the frequency of ventricular arrhythmias, appropriate ICD therapies or mortality. The presence of LGE emerges as a risk marker, associated with the classical predictors of sudden cardiac death in this population. However, larger studies are required to confirm its independent association with clinical events. Copyright © 2013 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

Comparison of Different Magnetic Resonance Cholangiography Techniques in Living Liver Donors Including Gd-EOB-DTPA Enhanced T1-Weighted Sequences

PubMed Central

Kinner, Sonja; Steinweg, Verena; Maderwald, Stefan; Radtke, Arnold; Sotiropoulos, Georgios; Forsting, Michael; Schroeder, Tobias

2014-01-01

Objectives Preoperative evaluation of potential living liver donors (PLLDs) includes the assessment of the biliary anatomy to avoid postoperative complications. Aim of this study was to compare T2-weighted (T2w) and Gd-EOB-DTPA enhanced T1-weighted (T1w) magnetic resonance cholangiography (MRC) techniques in the evaluation of PLLDs. Materials and Methods 30 PLLDs underwent MRC on a 1.5 T Magnetom Avanto (Siemens, Erlangen, Germany) using (A) 2D T2w HASTE (Half Fourier Acquisition Single Shot Turbo Spin Echo) fat saturated (fs) in axial plane, (B) 2D T2w HASTE fs thick slices in coronal plane, (C) free breathing 3D T2w TSE (turbo spin echo) RESTORE (high-resolution navigator corrected) plus (D) maximum intensity projections (MIPs), (E) T2w SPACE (sampling perfection with application optimized contrasts using different flip angle evolutions) plus (F) MIPs and (G) T2w TSE BLADE as well as Gd-EOB-DTPA T1w images without (G) and with (H) inversion recovery. Contrast enhanced CT cholangiography served as reference imaging modality. Two independent reviewers evaluated the biliary tract anatomy on a 5-point scale subjectively and objectively. Data sets were compared using a Mann-Whitney-U-test. Kappa values were also calculated. Results Source images and maximum intensity projections of 3D T2w TSE sequences (RESTORE and SPACE) proved to be best for subjective and objective evaluation directly followed by 2D HASTE sequences. Interobserver variabilities were good to excellent (k = 0.622–0.804). Conclusions 3D T2w sequences are essential for preoperative biliary tract evaluation in potential living liver donors. Furthermore, our results underline the value of different MRCP sequence types for the evaluation of the biliary anatomy in PLLDs including Gd-EOB-DTPA enhanced T1w MRC. PMID:25426932

Gadolinium chelate coated gold nanoparticles as contrast agents for both X-ray computed tomography and magnetic resonance imaging.

PubMed

Alric, Christophe; Taleb, Jacqueline; Le Duc, Géraldine; Mandon, Céline; Billotey, Claire; Le Meur-Herland, Alice; Brochard, Thierry; Vocanson, Francis; Janier, Marc; Perriat, Pascal; Roux, Stéphane; Tillement, Olivier

2008-05-07

Functionalized gold nanoparticles were applied as contrast agents for both in vivo X-ray and magnetic resonance imaging. These particles were obtained by encapsulating gold cores within a multilayered organic shell which is composed of gadolinium chelates bound to each other through disulfide bonds. The contrast enhancement in MRI stems from the presence of gadolinium ions which are entrapped in the organic shell, whereas the gold core provides a strong X-ray absorption. This study revealed that these particles suited for dual modality imaging freely circulate in the blood vessels without undesirable accumulation in the lungs, spleen, and liver.

Magnetic Resonance Imaging-Based Assessment of Gadolinium-Conjugated Diethylenetriamine Penta-Acetic Acid Test-Infusion in Detecting Dysfunction of Convection-Enhanced Delivery Catheters.

PubMed

van Putten, Erik H P; Wembacher-Schröder, Eva; Smits, Marion; Dirven, Clemens M F

2016-05-01

In a phase 1 trial conducted at our institute, convection-enhanced delivery (CED) was used to administrate the Delta-24-RGD adenovirus in patients with a recurrent glioblastoma multiforme. Infusion of the virus was preceded by a gadolinium-conjugated diethylenetriamine penta-acetic acid (Gd-DTPA) test-infusion. In the present study, we analyzed the results of Gd-DTPA test infusion through 50 catheters. Thirteen adults with a recurrent glioblastoma multiforme were enrolled in a larger phase 1 multicenter, dose-finding study, in which a conditionally replication-competent adenovirus was administered by CED. Up to 4 infusion catheters per patient were placed intra- and/or peritumorally. Before infusion of the virus, a Gd-DTPA infusion was performed for 6 hours, directly followed by a MRI scan. The MRIs were evaluated for catheter position, Gd-DTPA distribution outcome, and contrast leakage. Leakage of Gd-DTPA into the cerebrospinal fluid was detected in 17 of the 50 catheters (34%). Sulcus crossing was the most frequent cause of leakage. In 8 cases, leakage could only be detected on the fluid-attenuated inversion recovery sequence. Nonleaking catheters showed a significantly larger Gd-DTPA distribution fraction (volume of distribution/volume of infusion) than leaking catheters (P = 0.009). A significantly lower volume of distribution/volume of infusion was observed in intratumoral catheters, compared with peritumoral catheters (P = 0.004). Gd-DTPA test infusion did not result in significant changes in Karnofsky Performance Score and Neurological Status. Pre-CED treatment infusion of Gd-DTPA is an adequate and safe method to identify dysfunctional catheters. The use of an optimized drug delivery catheter is necessary to reduce leakage and improve the efficacy of intracerebral drug infusion. Copyright © 2016 Elsevier Inc. All rights reserved.

Studies of MRI relaxivities of gadolinium-labeled dendrons

NASA Astrophysics Data System (ADS)

Pan, Hongmu; Daniel, Marie-Christine

2011-05-01

In cancer detection, imaging techniques have a great importance in early diagnosis. The more sensitive the imaging technique and the earlier the tumor can be detected. Contrast agents have the capability to increase the sensitivity in imaging techniques such as magnetic resonance imaging (MRI). Until now, gadolinium-based contrast agents are mainly used for MRI, and show good enhancement. But improvement is needed for detection of smaller tumors at the earliest stage possible. The dendrons complexed with Gd(DOTA) were synthesized and evaluated as a new MRI contrast agent. The longitudinal and transverse relaxation effects were tested and compared with commercial drug Magnevist, Gd(DTPA).

Unilateral blindness with third cranial nerve palsy and abnormal enhancement of extraocular muscles on magnetic resonance imaging of orbit after the ingestion of methanol.

PubMed

Chung, Tae Nyoung; Kim, Sun Wook; Park, Yoo Seok; Park, Incheol

2010-05-01

Methanol is generally known to cause visual impairment and various systemic manifestations. There are a few reported specific findings for methanol intoxication on magnetic resonance imaging (MRI) of the brain. A case is reported of unilateral blindness with third cranial nerve palsy oculus sinister (OS) after the ingestion of methanol. Unilateral damage of the retina and optic nerve were confirmed by fundoscopy, flourescein angiography, visual evoked potential and electroretinogram. The optic nerve and extraocular muscles (superior rectus, medial rectus, inferior rectus and inferior oblique muscle) were enhanced by gadolinium-DTPA on MRI of the orbit. This is the first case report of permanent monocular blindness with confirmed unilateral damage of the retina and optic nerve, combined with third cranial nerve palsy after methanol ingestion.

Gd-DTPA-loaded polymer-metal complex micelles with high relaxivity for MR cancer imaging.

PubMed

Mi, Peng; Cabral, Horacio; Kokuryo, Daisuke; Rafi, Mohammad; Terada, Yasuko; Aoki, Ichio; Saga, Tsuneo; Takehiko, Ishii; Nishiyama, Nobuhiro; Kataoka, Kazunori

2013-01-01

Nanodevices for magnetic resonance imaging of cancer were self-assembled to core-shell micellar structures by metal complex formation of K(2)PtCl(6) with diethylenetriaminepentaacetic acid gadolinium (III) dihydrogen (Gd-DTPA), a T(1)-contrast agent, and poly(ethylene glycol)-b-poly{N-[N'-(2-aminoethyl)-2-aminoethyl]aspartamide} (PEG-b-PAsp(DET)) copolymer in aqueous solution. Gd-DTPA-loaded polymeric micelles (Gd-DTPA/m) showed a hydrodynamic diameter of 45 nm and a core size of 22 nm. Confining Gd-DTPA inside the core of the micelles increased the relaxivity of Gd-DTPA more than 13 times (48 mM(-1) s(-1)). In physiological conditions Gd-DTPA/m sustainedly released Gd-DTPA, while the Pt(IV) complexes remain bound to the polymer. Gd-DTPA/m extended the circulation time in plasma and augmented the tumor accumulation of Gd-DTPA leading to successful contrast enhancement of solid tumors. μ-Synchrotron radiation-X-ray fluorescence results confirmed that Gd-DTPA was delivered to the tumor site by the micelles. Our study provides a facile strategy for incorporating contrast agents, dyes and bioactive molecules into nanodevices for developing safe and efficient drug carriers for clinical application. Copyright © 2012 Elsevier Ltd. All rights reserved.

Integrin αvβ3-targeted dynamic contrast-enhanced magnetic resonance imaging using a gadolinium-loaded polyethylene gycol-dendrimer-cyclic RGD conjugate to evaluate tumor angiogenesis and to assess early antiangiogenic treatment response in a mouse xenograft tumor model.

PubMed

Chen, Wei-Tsung; Shih, Tiffany Ting Fang; Chen, Ran-Chou; Tu, Shin-Yang; Hsieh, Wen-Yuen; Yang, Pang-Chyr

2012-01-01

The purpose of this study was to validate an integrin αvβ3-targeted magnetic resonance contrast agent, PEG-G3-(Gd-DTPA)6-(cRGD-DTPA)2, for its ability to detect tumor angiogenesis and assess early response to antiangiogenic therapy using dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI). Integrin αvβ3-positive U87 cells and control groups were incubated with fluorescein-labeled cRGD-conjugated dendrimer, and the cellular attachment of the dendrimer was observed. DCE MRI was performed on mice bearing KB xenograft tumors using either PEG-G3-(Gd-DTPA)6-(cRGD-DTPA)2 or PEG-G3-(Gd-DTPA)6-(cRAD-DTPA)2. DCE MRI was also performed 2 hours after anti-integrin αvβ3 monoclonal antibody treatment and after bevacizumab treatment on days 3 and 6t. Using DCE MRI, the 30-minute contrast washout percentage was significantly lower in the cRGD-conjugate injection groups. The enhancement patterns were different between the two contrast injection groups. In the antiangiogenic therapy groups, a rapid increase in 30-minute contrast washout percentage was observed in both the LM609 and bevacizumab treatment groups, and this occurred before there was an observable decrease in tumor size. The integrin αvβ3 targeting ability of PEG-G3-(Gd-DTPA)6-(cRGD-DTPA)2 in vitro and in vivo was demonstrated. The 30-minute contrast washout percentage is a useful parameter for examining tumor angiogenesis and for the early assessment of antiangiogenic treatment response.

Electron magnetic resonance investigation of gadolinium diffusion in zircon powders

NASA Astrophysics Data System (ADS)

de Biasi, R. S.; Grillo, M. L. N.

2011-11-01

The electron magnetic resonance (EMR) technique was used to investigate the diffusion of gadolinium in zircon (ZrSiO4) powders. The EMR absorption intensity was measured for several annealing times and three different temperatures of isothermal annealing: 1273, 1323 and 1373 K. The activation energy for diffusion, calculated from the experimental data using a theoretical model based on the Fick equation, was found to be EA=506±5 kJ mol-1. This value is close to the ones for the diffusion of Gd in UO2 and CeO2, but much larger than for the diffusion of gadolinium in a compound with the same crystal structure as zircon, YVO4. This is attributed to a difference in the relative sizes of the ions involved in the diffusion process.

Quantitative assessment of hepatic fibrosis in chronic hepatitis B and C: T1 mapping on Gd-EOB-DTPA-enhanced liver magnetic resonance imaging.

PubMed

Pan, Shen; Wang, Xiao-Qi; Guo, Qi-Yong

2018-05-14

To assess the accuracy of Look-Locker on gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) for staging liver fibrosis in chronic hepatitis B/C (CHB/C). We prospectively included 109 patients with CHB or CHC who underwent a 3.0-Tesla MRI examination, including T1-weighted and Look-Locker sequences for T1 mapping. Hepatocyte fractions (HeF) and relaxation time reduction rate (RE) were measured for staging liver fibrosis. A receiver operating characteristic analysis using the area under the receiver operating characteristic curve (AUC) was used to compare the diagnostic performance in predicting liver fibrosis between HeF and RE. A total of 73 patients had both pathological results and MRI information. The number of patients in each fibrosis stage was evaluated semiquantitatively according to the METAVIR scoring system: F0, n = 23 (31.5%); F1, n = 19 (26.0%); F2, n = 13 (17.8%); F3, n = 6 (8.2%), and F4, n = 12 (16.4%). HeF by EOB enhancement imaging was significantly correlated with fibrosis stage ( r = -0.808, P < 0.05). AUC values for diagnosis of any (≥ F1), significant (≥ F2) or advanced (≥ F3) fibrosis, and cirrhosis (F4) using HeF were 0.837 (0.733-0.913), 0.890 (0.795-0.951), 0.957 (0.881-0.990), and 0.957 (0.882-0.991), respectively. HeF measurement was more accurate than use of RE in establishing liver fibrosis staging, suggesting that calculation of HeF is a superior noninvasive liver fibrosis staging method. A T1 mapping-based HeF method is an efficient diagnostic tool for the staging of liver fibrosis.

Gadolinium-enhanced computed tomographic angiography: current status.

PubMed

Rosioreanu, Alex; Alberico, Ronald A; Litwin, Alan; Hon, Man; Grossman, Zachary D; Katz, Douglas S

2005-01-01

This article reviews the research to date, as well as our clinical experience from two institutions, on gadolinium-enhanced computed tomographic angiography (gCTA) for imaging the body. gCTA may be an appropriate examination for the small percentage of patients who would benefit from noninvasive vascular imaging, but who have contraindications to both iodinated contrast and magnetic resonance imaging. gCTA is more expensive than CTA with iodinated contrast, due to the dose of gadolinium administered, and gCTA has limitations compared with CTA with iodinated contrast, in that parenchymal organs are not optimally enhanced at doses of 0.5 mmol/kg or lower. However, in our experience, gCTA has been a very useful problem-solving examination in carefully selected patients. With the advent of 16-64 detector CT, in combination with bolus tracking, we believe that the overall dose of gadolinium needed for diagnostic CTA examinations, while relatively high, can be safely administered.

Tumor Xenograft Response to Redox-Active Therapies Assessed by Magnetic Resonance Imaging Using a Thiol-Bearing DOTA Complex of Gadolinium1

PubMed Central

Guntle, Gerald P; Jagadish, Bhumasamudram; Mash, Eugene A; Powis, Garth; Dorr, Robert T; Raghunand, Natarajan

2012-01-01

Gd-LC6-SH is a thiol-bearing DOTA complex of gadolinium designed to bind plasma albumin at the conserved Cys34 site. The binding of Gd-LC6-SH shows sensitivity to the presence of competing thiols. We hypothesized that Gd-LC6-SH could provide magnetic resonance imaging (MRI) enhancement that is sensitive to tumor redox state and that the prolonged retention of albumin-bound Gd-LC6-SH in vivo can be exploited to identify a saturating dose above which the shortening of MRI longitudinal relaxation time (T1) of tissue is insensitive to the injected gadolinium dose. In the Mia-PaCa-2 pancreatic tumor xenograft model in SCID mice, both the small-molecule Gd-DTPA-BMA and the macromolecule Galbumin MRI contrast agents produced dose-dependent decreases in tumor T1. By contrast, the decreases in tumor T1 provided by Gd-LC6-SH at 0.05 and 0.1 mmol/kg were not significantly different at longer times after injection. SCID mice bearing Mia-PaCa-2 or NCI-N87 tumor xenografts were treated with either the glutathione synthesis inhibitor buthionine sulfoximine or the thiol-oxidizing anticancer drug Imexon, respectively. In both models, there was a significantly greater increase in tumor R1 (=1/T1) 60 minutes after injection of Gd-LC6-SH in drug-treated animals relative to saline-treated controls. In addition, Mercury Orange staining for nonprotein sulfhydryls was significantly decreased by drug treatment relative to controls in both tumor models. In summary, these studies show that thiol-bearing complexes of gadolinium such as Gd-LC6-SH can serve as redox-sensitive MRI contrast agents for detecting differences in tumor redox status and can be used to evaluate the effects of redox-active drugs. PMID:22741038

Hepatic Hemangiomas: Factors Associated with Pseudo Washout Sign on Gd-EOB-DTPA-enhanced MR Imaging.

PubMed

Tateyama, Akihiro; Fukukura, Yoshihiko; Takumi, Koji; Shindo, Toshikazu; Kumagae, Yuichi; Nakamura, Fumihiko

2016-01-01

Our study aim was to clarify the characteristics of hemangiomas with pseudo washout sign (PWS) by comparing their features with those of hemangiomas without PWS on gadolinium-ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance (MR) imaging. We evaluated the features of hemangiomas on Gd-EOB-DTPA-enhanced MR imaging of 70 hepatic hemangiomas in 31 patients, investigating the presence of peripheral or central nodular enhancement, diffuse enhancement, and arterioportal shunt during the arterial phase, fill-in enhancement during the portal venous phase, and PWS, which is low signal intensity during the late phase. We visually assessed the intensity of contrast enhancement of the lesion during the arterial, portal venous, late, and hepatobiliary phases using a 4-grade scale and used the Fisher exact and Mann-Whitney U tests to compare hemangiomas with and without PWS. We observed PWS in 33 (47%) of 70 hemangiomas, which were significantly smaller than the hemangiomas without PWS (17.4 mm ± 20.3 versus 30.1 mm ± 28.5; P = 0.005); more frequent diffuse enhancement in hemangiomas with PWS than those without (21.2% versus 2.7%; P = 0.026); and no significant differences in nodular enhancement (P = 0.231), arterioportal shunt (P = 0.403), or fill-in enhancement (P = 0.357) between hemangiomas with and without PWS. Visually determined grades of tumor contrast enhancement were significantly lower in hemangiomas with PWS during the portal venous (P = 0.007) and late (P < 0.001) phases. Small hemangiomas tend to decrease in signal intensity during the portal venous phase and show PWS during the late phase.

Gadolinium diethylenetriaminopentaacetic acid-loaded chitosan microspheres for gadolinium neutron-capture therapy.

PubMed

Saha, Tapan Kumar; Ichikawa, Hideki; Fukumori, Yoshinobu

2006-12-11

In order to provide a suitable device that would contain water-soluble drugs, highly water-soluble gadolinium diethylenetriaminopentaacetic acid-loaded chitosan microspheres (CMS-Gd-DTPA) were prepared by the emulsion method using glutaraldehyde as a cross-linker and Span 80 as a surfactant for gadolinium neutron-capture therapy of cancer. The gadolinium content and the mass median diameter of CMS-Gd-DTPA were estimated. The size and morphology of the CMS-Gd-DTPA were strongly influenced by the initial applied weight ratio of Gd-DTPA:chitosan. FTIR spectra showed that the electrostatic interaction between chitosan and Gd-DTPA accelerated the formation of gadolinium-enriched chitosan microspheres. Sufficient amounts of glutaraldehyde and Span 80 were necessary for producing discrete CMS-Gd-DTPA. The CMS-Gd-DTPA having a mass median diameter 11.7microm and 11.6% of gadolinium could be used in Gd-NCT following intratumoral injection.

Non-hypervascular hypointense nodules detected by Gd-EOB-DTPA-enhanced MRI are a risk factor for recurrence of HCC after hepatectomy.

PubMed

Toyoda, Hidenori; Kumada, Takashi; Tada, Toshifumi; Niinomi, Takuro; Ito, Takanori; Sone, Yasuhiro; Kaneoka, Yuji; Maeda, Atsuyuki

2013-06-01

The gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) often depicts non-hypervascular hypointense hepatic nodules during the hepatobiliary phase in patients with hepatocellular carcinoma (HCC). It is unclear whether the presence of these nodules is associated with HCC recurrence after hepatectomy. We conducted a prospective observational study to investigate the impact of the presence of non-hypervascular hypointense hepatic nodules on the hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI on the recurrence of HCC after hepatectomy. A total of 77 patients who underwent hepatectomy for primary, non-recurrent, hypervascular HCC were prospectively followed up after hepatectomy. Post-operative recurrence rates were compared according to the presence of non-hypervascular hypointense nodules on preoperative Gd-EOB-DTPA-enhanced MRI. Recurrence rates after hepatectomy were higher in patients with non-hypervascular hypointense nodules (risk ratio 1.9396 [1.3615-2.7222]) and the presence of non-hypervascular hypointense nodules was an independent factor associated with postoperative recurrence (risk ratio 2.1767 [1.5089-3.1105]) along with HCC differentiation and portal vein invasion. While no differences were found in the rate of intrahepatic metastasis recurrence based on the preoperative presence of non-hypervascular hypointense hepatic nodules, the rate of multicentric recurrence was significantly higher in patients with preoperative non-hypervascular hypointense hepatic nodules. Patients with preoperative non-hypervascular hypointense hepatic nodules detected during the hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI are at higher risk of HCC recurrence after hepatectomy, mainly due to multicentric recurrence. Copyright © 2013 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Superparamagnetic nanoparticles for enhanced magnetic resonance and multimodal imaging

NASA Astrophysics Data System (ADS)

Sikma, Elise Ann Schultz

Magnetic resonance imaging (MRI) is a powerful tool for noninvasive tomographic imaging of biological systems with high spatial and temporal resolution. Superparamagnetic (SPM) nanoparticles have emerged as highly effective MR contrast agents due to their biocompatibility, ease of surface modification and magnetic properties. Conventional nanoparticle contrast agents suffer from difficult synthetic reproducibility, polydisperse sizes and weak magnetism. Numerous synthetic techniques and nanoparticle formulations have been developed to overcome these barriers. However, there are still major limitations in the development of new nanoparticle-based probes for MR and multimodal imaging including low signal amplification and absence of biochemical reporters. To address these issues, a set of multimodal (T2/optical) and dual contrast (T1/T2) nanoparticle probes has been developed. Their unique magnetic properties and imaging capabilities were thoroughly explored. An enzyme-activatable contrast agent is currently being developed as an innovative means for early in vivo detection of cancer at the cellular level. Multimodal probes function by combining the strengths of multiple imaging techniques into a single agent. Co-registration of data obtained by multiple imaging modalities validates the data, enhancing its quality and reliability. A series of T2/optical probes were successfully synthesized by attachment of a fluorescent dye to the surface of different types of nanoparticles. The multimodal nanoparticles generated sufficient MR and fluorescence signal to image transplanted islets in vivo. Dual contrast T1/T2 imaging probes were designed to overcome disadvantages inherent in the individual T1 and T2 components. A class of T1/T2 agents was developed consisting of a gadolinium (III) complex (DTPA chelate or DO3A macrocycle) conjugated to a biocompatible silica-coated metal oxide nanoparticle through a disulfide linker. The disulfide linker has the ability to be reduced

Thermodynamic stability and kinetic inertness of a Gd-DTPA bisamide complex grafted onto gold nanoparticles.

PubMed

Mogilireddy, Vijetha; Déchamps-Olivier, Isabelle; Alric, Christophe; Laurent, Gautier; Laurent, Sophie; Vander Elst, Luce; Muller, Robert; Bazzi, Rana; Roux, Stéphane; Tillement, Olivier; Chuburu, Françoise

2015-01-01

Gold nanoparticles coated by gadolinium (III) chelates (Au@DTDTPA) where DTDTPA is a dithiolated bisamide derivative of diethylenetriamine-N,N,N',N'',N''-pentaacetic acid (DTPA), constituted contrast agents for both X-ray computed tomography and magnetic resonance imaging. In an MRI context, highly stable Gd(3+) complexes are needed for in vivo applications. Thus, knowledge of the thermodynamic stability and kinetic inertness of these chelates, when grafted onto gold nanoparticles, is crucial since bisamide DTPA chelates are usually less suited for Gd(3+) coordination than DTPA. Therefore, these parameters were evaluated by means of potentiometric titrations and relaxivity measurements. The results showed that, when the chelates were grafted onto the nanoparticle, not only their thermodynamic stability but also their kinetic inertness were improved. These positive effects were correlated to the chelate packing at the nanoparticle surface that stabilized the corresponding Gd(3+) complexes and greatly enhanced their kinetic inertness. Copyright © 2014 John Wiley & Sons, Ltd.

Evaluation of Marrow Perfusion in the Femoral Head by Dynamic Magnetic Resonance Imaging

PubMed Central

Tsukamoto, Hiroshi; Kang, Young S.; Jones, Lynne C.; Cova, Maria; Herold, Christian J.; McVeigh, Elliot; Hungerford, David S.; Zerhouni, Elias A.

2007-01-01

Rationale and Objectives There is a continuing need for a greater sensitivity of magnetic resonance imaging (MRI) in the diagnosis of avascular necrosis (AVN). Previously, it was demonstrated that a dynamic MRI method, with gadolinium-DTPA (Gd-DTPA) enhancement, can detect acute changes not seen on spin-echo images after arterial occlusion in a dog model. Because venous congestion appears to be a more directly relevant hemodynamic abnormality in a majority of clinical AVN cases, the authors extended the dynamic MRI technique to study changes in venous occlusion. Methods Dynamic MRI of the proximal femur was performed in five adult dogs before and after unilateral ligation of common iliac and lateral circumflex veins. Sixteen sequential gradient-recalled pulse sequence (GRASS) images (time resolution = 45 mseconds, echo time = 9 mseconds, flip angle = 65°) were obtained immediately after a bolus intravenous injection of 0.2 mmol/kg of Gd-DTPA. Simultaneous measurements of regional blood flow were made using the radioactive microsphere method. Results After venous ligation, there was a 25% to 45% decrease in the degree of enhancement compared with preligation values on the ligated side. The decrease in cumulative enhancement (integrated over the entire time course) was statistically significant. The occlusion technique was verified by confirming a statistically significant decrease in blood flow determined by the microsphere method. Conclusions Dynamic Gd-DTPA-enhanced fast MRI technique can detect acute changes in bone marrow perfusion due to venous occlusion. This technique may have applications in the early detection of nontraumatic AVN. PMID:1601616

Kondo effect and enhanced magnetic properties in gadolinium functionalized carbon nanotube supramolecular complex.

PubMed

Ncube, S; Coleman, C; Strydom, A; Flahaut, E; de Sousa, A; Bhattacharyya, S

2018-05-23

We report on the enhancement of magnetic properties of multiwalled carbon nanotubes (MWNTs) functionalized with a gadolinium based supramolecular complex. By employing a newly developed synthesis technique we find that the functionalization method of the nanocomposite enhances the strength of magnetic interaction leading to a large effective moment of 15.79 µ B and non-superparamagnetic behaviour unlike what has been previously reported. Saturating resistance at low temperatures is fitted with the numerical renormalization group formula verifying the Kondo effect for magnetic impurities on a metallic electron system. Magnetoresistance shows devices fabricated from aligned gadolinium functionalized MWNTs (Gd-Fctn-MWNTs) exhibit spin-valve switching behaviour of up to 8%. This study highlights the possibility of enhancing magnetic interactions in carbon systems through chemical modification, moreover we demonstrate the rich physics that might be useful for developing spin based quantum computing elements based on one-dimensional (1D) channels.

Gadolinium-based nanoparticles for highly efficient T1-weighted magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Lim, Eun-Kyung; Kang, Byunghoon; Choi, Yuna; Jang, Eunji; Han, Seungmin; Lee, Kwangyeol; Suh, Jin-Suck; Haam, Seungjoo; Huh, Yong-Min

2014-06-01

We developed Pyrene-Gadolinium (Py-Gd) nanoparticles as pH-sensitive magnetic resonance imaging (MRI) contrast agents capable of showing a high-Mr signal in cancer-specific environments, such as acidic conditions. Py-Gd nanoparticles were prepared by coating Py-Gd, which is a complex of gadolinium with pyrenyl molecules, with pyrenyl polyethyleneglycol PEG using a nano-emulsion method. These particles show better longitudinal relaxation time (T1) MR signals in acidic conditions than they do in neutral conditions. Furthermore, the particles exhibit biocompatibility and MR contrast effects in both in vitro and in vivo studies. From these results, we confirm that Py-Gd nanoparticles have the potential to be applied for accurate cancer diagnosis and therapy.

[Studies on renal damages after extracorporeal shock wave lithotripsy using Gd-DTPA-enhanced dynamic MRI].

PubMed

Umekawa, T; Kohri, K; Iguchi, M; Kurita, T

1991-11-01

Renal damages after ESWL treatment were examined by Gd-DTPA enhanced dynamic MRI. Gd-DTPA was used as the contrast medium and fast magnetic resonance imaging with suspended respiration using the flip angle of 20 degrees and gradient echo technique at 0.5 Tesla was used for photographing. In normal kidneys, a low intensity band was observed with the passage of Gd-DTPA through the kidney from 1 to 2 minutes after the injection. In patients who underwent ESWL treatment, however, the low intensity band which was observed before ESWL treatment became partly obscure after ESWL treatment. Furthermore, these find changes in the renal parenchyma could not be fully detected by usual MRI which does not use Gd-DTPA. Gd-DTPA enhanced dynamic MRI was considered to be effective for finding the limited dose of shock waves for ESWL treatment.

Gadolinium-free MR in coarctation-can contrast-enhanced MR angiography be replaced?

PubMed

Kalmar, Peter I; Koestenberger, Martin; Marterer, Robert; Tschauner, Sebastian; Sorantin, Erich

2016-01-01

To determine the difference in vessel measurements, signal-to-noise ratio (SNR), and voxel size between contrast-enhanced and noncontrast magnetic resonance techniques in patients with coarctation of the aorta (CoA). In 39 patients, vessel size, SNR, and voxel size were compared in cine magnetic resonance imaging (MRI), gadolinium-free magnetic resonance angiography (Gd-free MRA), and contrast-enhanced MRA (ce-MRA). There was no significant difference in measurement and SNR, but there was a significant difference in voxel size (P<.001). Our results show that, in CoA patients, monitoring of vessel size using cine MRI and Gd-free MRA is equivalent to ce-MRA while being less invasive. Copyright © 2016 Elsevier Inc. All rights reserved.

Application of classification trees for the qualitative differentiation of focal liver lesions suspicious for metastasis in gadolinium-EOB-DTPA-enhanced liver MR imaging.

PubMed

Schelhorn, J; Benndorf, M; Dietzel, M; Burmeister, H P; Kaiser, W A; Baltzer, P A T

2012-09-01

To evaluate the diagnostic accuracy of qualitative descriptors alone and in combination for the classification of focal liver lesions (FLLs) suspicious for metastasis in gadolinium-EOB-DTPA-enhanced liver MR imaging. Consecutive patients with clinically suspected liver metastases were eligible for this retrospective investigation. 50 patients met the inclusion criteria. All underwent Gd-EOB-DTPA-enhanced liver MRI (T2w, chemical shift T1w, dynamic T1w). Primary liver malignancies or treated lesions were excluded. All investigations were read by two blinded observers (O1, O2). Both independently identified the presence of lesions and evaluated predefined qualitative lesion descriptors (signal intensities, enhancement pattern and morphology). A reference standard was determined under consideration of all clinical and follow-up information. Statistical analysis besides contingency tables (chi square, kappa statistics) included descriptor combinations using classification trees (CHAID methodology) as well as ROC analysis. In 38 patients, 120 FLLs (52 benign, 68 malignant) were present. 115 (48 benign, 67 malignant) were identified by the observers. The enhancement pattern, relative SI upon T2w and late enhanced T1w images contributed significantly to the differentiation of FLLs. The overall classification accuracy was 91.3 % (O1) and 88.7 % (O2), kappa = 0.902. The combination of qualitative lesion descriptors proposed in this work revealed high diagnostic accuracy and interobserver agreement in the differentiation of focal liver lesions suspicious for metastases using Gd-EOB-DTPA-enhanced liver MRI. © Georg Thieme Verlag KG Stuttgart · New York.

Reliability of gadolinium-enhanced magnetic resonance imaging findings and their correlation with clinical outcome in patients with sciatica.

PubMed

el Barzouhi, Abdelilah; Vleggeert-Lankamp, Carmen L A M; Lycklama à Nijeholt, Geert J; Van der Kallen, Bas F; van den Hout, Wilbert B; Koes, Bart W; Peul, Wilco C

2014-11-01

Gadolinium-enhanced magnetic resonance imaging (Gd-MRI) is often performed in the evaluation of patients with persistent sciatica after lumbar disc surgery. However, correlation between enhancement and clinical findings is debated, and limited data are available regarding the reliability of enhancement findings. To evaluate the reliability of Gd-MRI findings and their correlation with clinical findings in patients with sciatica. Prospective observational evaluation of patients who were enrolled in a randomized trial with 1-year follow-up. Patients with 6- to 12-week sciatica, who participated in a multicentre randomized clinical trial comparing an early surgery strategy with prolonged conservative care with surgery if needed. In total 204 patients underwent Gd-MRI at baseline and after 1 year. Patients were assessed by means of the Roland Disability Questionnaire (RDQ) for sciatica, visual analog scale (VAS) for leg pain, and patient-reported perceived recovery at 1 year. Kappa coefficients were used to assess interobserver reliability. In total, 204 patients underwent Gd-MRI at baseline and after 1 year. Magnetic resonance imaging findings were correlated to the outcome measures using the Mann-Whitney U test for continuous data and Fisher exact tests for categorical data. Poor-to-moderate agreement was observed regarding Gd enhancement of the herniated disc and compressed nerve root (kappa<0.41), which was in contrast with excellent interobserver agreement of the disc level of the herniated disc and compressed nerve root (kappa>0.95). Of the 59 patients with an enhancing herniated disc at 1 year, 86% reported recovery compared with 100% of the 12 patients with nonenhancing herniated discs (p=.34). Of the 12 patients with enhancement of the most affected nerve root at 1 year, 83% reported recovery compared with 85% of the 192 patients with no enhancement (p=.69). Patients with and without enhancing herniated discs or nerve roots at 1 year reported comparable

Enhanced conjugation stability and blood circulation time of macromolecular gadolinium-DTPA contrast agent.

PubMed

Jenjob, Ratchapol; Kun, Na; Ghee, Jung Yeon; Shen, Zheyu; Wu, Xiaoxia; Cho, Steve K; Lee, Don Haeng; Yang, Su-Geun

2016-04-01

In this study, we prepared macromolecular MR T1 contrast agent: pullulan-conjugated Gd diethylene triamine pentaacetate (Gd-DTPA-Pullulan) and estimated residual free Gd(3+), chelation stability in competition with metal ions, plasma and tissue pharmacokinetics, and abdominal MR contrast on rats. Residual free Gd(3+) in Gd-DTPA-Pullulan was measured using colorimetric spectroscopy. The transmetalation of Gd(3+) incubated with Ca(2+) was performed by using a dialysis membrane (MWCO 100-500 Da) and investigated by ICP-OES. The plasma concentration profiles of Gd-DTPA-Pullulan were estimated after intravenous injection at a dose 0.1 mmol/kg of Gd. The coronal-plane abdominal images of normal rats were observed by MR imaging. The content of free Gd(3+), the toxic residual form, was less than 0.01%. Chelation stability of Gd-DTPA-Pullulan was estimated, and only 0.2% and 0.00045% of Gd(3+) were released from Gd-DTPA-Pullulan after 2h incubation with Ca(2+) and Fe(2+), respectively. Gd-DTPA-Pullulan displayed the extended plasma half-life (t1/2,α=0.43 h, t1/2,β=2.32 h), much longer than 0.11h and 0.79 h of Gd-EOB-DTPA. Abdominal MR imaging showed Gd-DTPA-Pullulan maintained initial MR contrast for 30 min. The extended plasma half-life of Gd-DTPA-Pullulan probably allows the prolonged MR acquisition time in clinic with enhanced MR contrast. Copyright © 2016 Elsevier B.V. All rights reserved.

Characteristics of Gadolinium Oxide Nanoparticles Using Terahertz Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Dongkyu; Maeng, Inhee; Son, Joo-Hiuk

2009-04-19

The penetration property of the terahertz electromagnetic (THz) wave is relevant to its use. We used the THz wave spectroscopy system which easily penetrates some materials that do not contain water, e.g., plastic and ceramics. The system has been developed for several purposes, including measuring the properties of semiconductors and bio-materials, and detecting plastic bombs and ceramic knives at airports. It is also used for medical imaging systems, such as magnetic resonance imaging (MRI), at some research institutes. It can show not only the difference in amplitude, but also the difference of the phase of each point of sample. MRImore » technology usually uses contrast agents to enhance the quality of the image. Gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA), made with a heavy metal ion, is commonly used as a clinical MRI contrast agent. Gadolinium oxide (Gd{sub 2}O{sub 3}) nanoparticle is a new contrast agent. It serves to equip the core of each particle with antibodies or ligands. It can freely circulate in blood vessels without amassing in the liver or lungs. This study shows the characteristics of gadolinium oxide nanoparticles to further advance terahertz medical imaging.« less

Gd-EOB-DTPA-enhanced 3.0-Tesla MRI findings for the preoperative detection of focal liver lesions: Comparison with iodine-enhanced multi-detector computed tomography

NASA Astrophysics Data System (ADS)

Park, Hyong-Hu; Goo, Eun-Hoe; Im, In-Chul; Lee, Jae-Seung; Kim, Moon-Jib; Kwak, Byung-Joon; Chung, Woon-Kwan; Dong, Kyung-Rae

2012-12-01

The safety of gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic-acid (Gd-EOB-DTPA) has been confirmed, but more study is needed to assess the diagnostic accuracy of Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) in patients with a hepatocellular carcinoma (HCC) for whom surgical treatment is considered or with a metastatic hepatoma. Research is also needed to examine the rate of detection of hepatic lesions compared to multi-detector computed tomography (MDCT), which is used most frequently to localize and characterize a HCC. Gd-EOB-DTPA-enhanced MRI and iodine-enhanced MDCT imaging were compared for the preoperative detection of focal liver lesions. The clinical usefulness of each method was examined. The current study enrolled 79 patients with focal liver lesions who preoperatively underwent MRI and MDCT. In these patients, there was less than one month between the two diagnostic modalities. Imaging data were taken before and after contrast enhancement in both methods. To evaluate the images, we analyzed the signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR) in the lesions and the liver parenchyma. To compare the sensitivity of the two methods, we performed a quantitative analysis of the percentage signal intensity of the liver (PSIL) on a high resolution picture archiving and communication system (PACS) monitor (paired-samples t-test, p < 0.05). The enhancement was evaluated based on a consensus of four observers. The enhancement pattern and the morphological features during the arterial and the delayed phases were correlated between the Gd-EOB-DTPA-enhanced MRI findings and the iodine-enhanced MDCT by using an adjusted x2 test. The SNRs, CNRs, and PSIL all had a greater detection rate in Gd-EOB-DTPA enhanced MRI than in iodine-enhanced MDCT. Hepatocyte-selective uptake was observed 20 minutes after the injection in the focal nodular hyperplasia (FNH, 9/9), adenoma (9/10), and highly-differentiated HCC (grade G1, 27/30). Rim

Synthesis of DTPA analogues derived from piperidine and azepane: potential contrast enhancement agents for magnetic resonance imaging.

PubMed

Chong, H S; Garmestani, K; Bryant, L H; Brechbiel, M W

2001-11-16

Two DTPA derivatives (PIP-DTPA and AZEP-DTPA) as potential contrast enhancement agents in MRI are synthesized. The T1 and T2 relaxivities of their corresponding Gd(III) complexes are reported. At clinically relevant field strengths, the relaxivities of the complexes are comparable to that of the contrast agent, Gd(DTPA) which is in clinical use. The serum stability of the (153)Gd-labeled complexes is assessed by measuring the release of (153)Gd from the ligands. The radiolabeled Gd chelates are found to be kinetically stable in human serum for up to at least 14 days without any measurable loss of radioactivity.

Lectin conjugates as biospecific contrast agents for MRI. Coupling of Lycopersicon esculentum agglutinin to linear water-soluble DTPA-loaded oligomers.

PubMed

Pashkunova-Martic, Irena; Kremser, Christian; Galanski, Markus; Schluga, Petra; Arion, Vladimir; Debbage, Paul; Jaschke, Werner; Keppler, Bernhard

2011-06-01

Magnetic resonance imaging (MRI) requires synthesis of contrast media bearing targeting groups and numerous gadolinium chelating groups generating high relaxivity. This paper explores the results of linking the gadolinium chelates to the targeting group, a protein molecule, via various types of linkers. Polycondensates of diethylenetriaminepentaacetic acid (DTPA) with either diols or diamines were synthesised and coupled to the targeting group, a lectin (Lycopersicon esculentum agglutinin, tomato lectin) which binds with high affinity to specific oligosaccharide configurations in the endothelial glycocalyx. The polycondensates bear up to four carboxylic groups per constitutive unit. Gd-chelate bonds are created through dative interactions with the unshared pair of electrons on each oxygen and nitrogen atom on DTPA. This is mandatory for complexation of Gd(III) and avoidance of the severe toxicity of free gadolinium ions. The polymer-DTPA compounds were characterised by (1)H NMR and mass spectrometry. The final lectin-DTPA-polycondensate conjugates were purified by fast protein liquid chromatography (FPLC). The capacity for specific binding was assessed, and the MRI properties were examined in order to evaluate the use of these oligomers as components of selective perfusional contrast agents.

Characteristics of Gadolinium Oxide Nanoparticles Using Terahertz Spectroscopy (abstract)

NASA Astrophysics Data System (ADS)

Lee, Dongkyu; Maeng, Inhee; Oh, Seung Jae; Kim, Taekhoon; Cho, Byung Kyu; Lee, Kwangyeol; Son, Joo-Hiuk

2009-04-01

The penetration property of the terahertz electromagnetic (THz) wave is relevant to its use. We used the THz wave spectroscopy system which easily penetrates some materials that do not contain water, e.g., plastic and ceramics. The system has been developed for several purposes, including measuring the properties of semiconductors and bio-materials, and detecting plastic bombs and ceramic knives at airports. It is also used for medical imaging systems, such as magnetic resonance imaging (MRI), at some research institutes. It can show not only the difference in amplitude, but also the difference of the phase of each point of sample. MRI technology usually uses contrast agents to enhance the quality of the image. Gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA), made with a heavy metal ion, is commonly used as a clinical MRI contrast agent. Gadolinium oxide (Gd2O3) nanoparticle is a new contrast agent. It serves to equip the core of each particle with antibodies or ligands. It can freely circulate in blood vessels without amassing in the liver or lungs. This study shows the characteristics of gadolinium oxide nanoparticles to further advance terahertz medical imaging.

Contrast enhanced liver MRI in patients with primary sclerosing cholangitis: inverse appearance of focal confluent fibrosis on delayed phase MR images with hepatocyte specific versus extracellular gadolinium based contrast agents.

PubMed

Husarik, Daniela B; Gupta, Rajan T; Ringe, Kristina I; Boll, Daniel T; Merkle, Elmar M

2011-12-01

To assess the enhancement pattern of focal confluent fibrosis (FCF) on contrast-enhanced hepatic magnetic resonance imaging (MRI) using hepatocyte-specific (Gd-EOB-DTPA) and extracellular (ECA) gadolinium-based contrast agents in patients with primary sclerosing cholangitis (PSC). After institutional review board approval, 10 patients with PSC (6 male, 4 female; 33-61 years) with 13 FCF were included in this retrospective study. All patients had a Gd-EOB-DTPA-enhanced liver MRI exam, and a comparison ECA-enhanced MRI. On each T1-weighted dynamic dataset, the signal intensity (SI) of FCF and the surrounding liver as well as the paraspinal muscle (M) were measured. In the Gd-EOB-DTPA group, hepatocyte phase images were also included. SI FCF/SI M, SI liver/SI M, and [(SI liver - SI FCF)/SI liver] were compared between the different contrast agents for each dynamic phase using the paired Student's t-test. There was no significant difference in SI FCF/SI M in all imaging phases. SI liver/SI M was significantly higher for the Gd-EOB-DTPA group in the delayed phase (P < .001), whereas there was no significant difference in all other imaging phases. In the Gd-EOB-DTPA group, mean [(SI liver - SI FCF)/SI liver] were as follows (values for ECA group in parentheses): unenhanced phase: 0.26 (0.26); arterial phase: 0.01 (-0.31); portal venous phase (PVP): -0.05 (-0.26); delayed phase (DP): 0.14 (-0.54); and hepatocyte phase: 0.26. Differences were significant for the DP (P < .001). On delayed phase MR images the FCF-to-liver contrast is reversed with the lesions appearing hyperintense on ECA enhanced images and hypointense on Gd-EOB-DTPA-enhanced images. Copyright © 2011 AUR. Published by Elsevier Inc. All rights reserved.

Highly stabilized gadolinium chelates functionalized on metal nanoparticles as magnetic resonance imaging contrast agent

NASA Astrophysics Data System (ADS)

Siddiqui, Talha S.

Magnetic resonance imaging (MRI) is a non-invasive method for imaging and diagnosing tissue damage, organ function and the vascular system. Magnevist(TM) a complex of diethylenetriaminepentaacetic acid (DTPA) and Gd3+ is a clinically approved contrast agent for MRI. A derivative of DTPA was formed by the addition of two cysteine groups (DTPA-L-Cys) through amide linkage. The Gd complex of this ligand bonds with the silver surfaces through the cysteine thiols. GdDTPA-L-Cys was bound to ˜10nm diameter Ag nanoparticles for use as a multifunctional MRI contrast agent. The ligand and complex were characterized by 1H and 13C NMR, ESI-MS and IR spectroscopy. The silver construct was characterized by TEM, TGA and UV-Vis absorption spectra. The per metal complex r1 relaxivity of GdDTPA-L-Cys{Ag} greater than that of Magnavist(TM) with the same molarity for both compounds. The synthesis of a DTPA derivative is described that allows it to bind to silver or gold nanoparticles through a single thiol linkage (DTPASH). The resulting Gd complex, GdDTPASH, was bound to Ag nanoparticles to create a single monolayer on the surface. The construct was further stabilized in buffered solution with the addition of a thiolated PEG chain. The highly stabilized nanoparticle construct delivers a high payload of Gd compelex and is an effective T1 brightening agent. The production of this type of construct opens the way for engineered multimodal MRI contrast agents.

Trapping effect on a small molecular drug with vascular-disrupting agent CA4P in rodent H22 hepatic tumor model: in vivo magnetic resonance imaging and postmortem inductively coupled plasma atomic emission spectroscopy.

PubMed

Gao, Meng; Yao, Nan; Huang, Dejian; Jiang, Cuihua; Feng, Yuanbo; Li, Yue; Lou, Bin; Peng, Fei; Sun, Ziping; Ni, Yicheng; Zhang, Jian

2015-06-01

The aim of the present study is to verify the trapping effect of combretastatin A-4-phosphate (CA4P) on small molecular drugs in rodent tumors. Mice with H22 hepatocarcinoma were randomized into groups A and B. Magnetic resonance imaging (MRI) of T1WI, T2WI, and DWI was performed as baseline. Mice in group A were injected with Gd-DTPA and PBS. Mice in group B were injected with Gd-DTPA and CA4P. All mice undergo CE-T1WI at 0 h, 3 h, 6 h, 12 h, and 24 h. Enhancing efficacy of the two groups on CE-T1WI was compared with the signal-to-noise ratio (SNR) calculated. Concentrations of gadolinium measured by ICP-AES in the tumor were compared between groups. On the early CE-T1WI, tumors were equally enhanced in both groups. On the delayed CE-T1WI, the enhancing effect of group A was weaker than that of group B. The SNR and the concentration of gadolinium within the tumor of group A were lower than that of group B at 6 h, 12 h, and 24 h after administration. This study indicates that CA4P could improve the retention of Gd-DTPA in the tumor and MRI allowed dynamically monitoring trapping effects of CA4P on local retention of Gd-DTPA as a small molecular drug.

Real time magnetic resonance guided endomyocardial local delivery

PubMed Central

Corti, R; Badimon, J; Mizsei, G; Macaluso, F; Lee, M; Licato, P; Viles-Gonzalez, J F; Fuster, V; Sherman, W

2005-01-01

Objective: To investigate the feasibility of targeting various areas of left ventricle myocardium under real time magnetic resonance (MR) imaging with a customised injection catheter equipped with a miniaturised coil. Design: A needle injection catheter with a mounted resonant solenoid circuit (coil) at its tip was designed and constructed. A 1.5 T MR scanner with customised real time sequence combined with in-room scan running capabilities was used. With this system, various myocardial areas within the left ventricle were targeted and injected with a gadolinium-diethylenetriaminepentaacetic acid (DTPA) and Indian ink mixture. Results: Real time sequencing at 10 frames/s allowed clear visualisation of the moving catheter and its transit through the aorta into the ventricle, as well as targeting of all ventricle wall segments without further image enhancement techniques. All injections were visualised by real time MR imaging and verified by gross pathology. Conclusion: The tracking device allowed real time in vivo visualisation of catheters in the aorta and left ventricle as well as precise targeting of myocardial areas. The use of this real time catheter tracking may enable precise and adequate delivery of agents for tissue regeneration. PMID:15710717

Liver Function Assessment by Magnetic Resonance Imaging.

PubMed

Ünal, Emre; Akata, Deniz; Karcaaltincaba, Musturay

2016-12-01

Liver function assessment by hepatocyte-specific contrast-enhanced magnetic resonance imaging is becoming a new biomarker. Liver function can be assessed by T1 mapping (reduction rate) and signal intensity measurement (relative enhancement ratio) before and after GD-EOB-DTPA (gadoxetic acid) administration, as alternative to Tc-99m galactosyl serum albumin scintigraphy, 99m Tc-labeled mebrofenin scintigraphy, and indocyanine green clearance test. Magnetic resonance imaging assessment of liver function can enable diagnosis of cirrhosis, nonalcoholic fatty liver disease associated fibrosis and steatohepatitis, primary sclerosing cholangitis, toxic hepatitis, and chemotherapy and radiotherapy-related changes, which may be only visible on hepatobiliary phase images. Simple visual assessment of signal intensity at hepatobiliary phase images is important for the diagnosis of different patterns of liver dysfunction including diffuse, lobar, segmental, and subsegmental forms. Furthermore, preoperative assessment of liver function is feasible before oncologic hepatic surgery, which may be important to prevent posthepatectomy liver failure and to estimate future remnant volume. Functional magnetic resonance cholangiography obtained by T1-weighted images at hepatobiliary phase can allow diagnosis of acalculous cholecystitis, biliary leakage, bile reflux to the stomach, sphincter of oddi dysfunction, and lesions with communication to biliary tree. Functional information can be easily obtained when Gd-EOB-DTPA is used for liver magnetic resonance imaging. Copyright © 2016 Elsevier Inc. All rights reserved.

Magnetic resonance imaging with gadolinium arthrography to assess acetabular cartilage delamination.

PubMed

Zaragoza, Edward; Lattanzio, Pierre-Jean; Beaule, Paul E

2009-01-01

Recent reports have demonstrated magnetic resonance imaging (MRI) as a promising technique in detecting articular cartilage lesions of the hip joint. The purpose of our study was to evaluate the diagnostic performance of MRI with gadolinium arthrography in detecting acetabular cartilage delamination in patients with pre-arthritic hip pain. 46 patients (48 hips) underwent surgical dislocation of the hip. Mean age was 38.8 (range 17-56). There were 26 males and 20 females. All patients had Magnetic Resonance Imaging with gadolinium arthrography (MRA) before undergoing open hip surgery where the acetabular cartilage was inspected. Acetabular cartilage delamination on MRA was seen on sagittal images as a linear intra-articular filling defect of low signal intensity >1mm in thickness on T1 weighted images and surrounded by contrast. On MRA all hips had a labral tear confirmed at surgery. At surgery 30 hips had evidence of acetabular cartilage delamination, 4 hips had ulceration and 14 had no articular cartilage damage. The majority of labral tears and cartilage damage were located in the antero-superior quadrant. The sensitivity and specificity of MRA detection of cartilage delamination confirmed at surgery were 97% and 84%, respectively. The positive and negative predictive values of the MRA finding were 90% and 94%, respectively. The presence of the acetabular cartilage delamination represents an early stage of articular cartilage degeneration. When evaluating a young adult with hip pain, labral tears in association with cartilage delamination should be considered. MRA represents an effective diagnostic tool.

Subcellular SIMS imaging of gadolinium isotopes in human glioblastoma cells treated with a gadolinium containing MRI agent

NASA Astrophysics Data System (ADS)

Smith, Duane R.; Lorey, Daniel R.; Chandra, Subhash

2004-06-01

Neutron capture therapy is an experimental binary radiotherapeutic modality for the treatment of brain tumors such as glioblastoma multiforme. Recently, neutron capture therapy with gadolinium-157 has gained attention, and techniques for studying the subcellular distribution of gadolinium-157 are needed. In this preliminary study, we have been able to image the subcellular distribution of gadolinium-157, as well as the other six naturally abundant isotopes of gadolinium, with SIMS ion microscopy. T98G human glioblastoma cells were treated for 24 h with 25 mg/ml of the metal ion complex diethylenetriaminepentaacetic acid Gd(III) dihydrogen salt hydrate (Gd-DTPA). Gd-DTPA is a contrast enhancing agent used for MRI of brain tumors, blood-brain barrier impairment, diseases of the central nervous system, etc. A highly heterogeneous subcellular distribution was observed for gadolinium-157. The nuclei in each cell were distinctly lower in gadolinium-157 than in the cytoplasm. Even within the cytoplasm the gadolinium-157 was heterogeneously distributed. The other six naturally abundant isotopes of gadolinium were imaged from the same cells and exhibited a subcellular distribution consistent with that observed for gadolinium-157. These observations indicate that SIMS ion microscopy may be a viable approach for subcellular studies of gadolinium containing neutron capture therapy drugs and may even play a major role in the development and validation of new gadolinium contrast enhancing agents for diagnostic MRI applications.

Evaluation of gadolinium-EOB-DTPA uptake after portal vein embolization: value of an increased flip angle.

PubMed

Geisel, Dominik; Lüdemann, Lutz; Wagner, Clemens; Stelter, Lars; Grieser, Christian; Malinowski, Maciej; Stockmann, Martin; Seehofer, Daniel; Hamm, Bernd; Gebauer, Bernhard; Denecke, Timm

2014-03-01

The optimal sequence for Gd-EOB-DTPA uptake measurement in the liver with the purpose of liver function measurement is still not defined. To prospectively evaluate the effect of an increased flip angle (FA) of a T1-weighted fat-saturated 3D sequence for the measurement of hepatocyte uptake of Gd-EOB-DTPA magnetic resonance imaging (MRI) after right portal vein embolization (PVE). Ten patients who received a PVE prior to an extended hemihepatectomy were examined 14 days after PVE using Gd-EOB-DTPA enhanced MRI of the liver using the standard FA of 10° and the increased FA of 30°. Relative enhancement of the right liver lobe (RLL) was 0.52 ± 0.12 for 10° and 1.41 ± 0.39 for 30°. Relative enhancement of the left liver lobe (LLL) was 0.58 ± 0.11 for 10° and 2.05 ± 0.61 for 30°. Relative enhancement of the RLL was significantly higher for 30° than for 10° (P = 0.009) and significantly higher in the 30° than in the 10° sequences (P = 0.005) for the LLL. A flip angle of 30° increases the contrast between liver partitions with and without portal venous embolization. Thereby, the sensitivity for differences in uptake intensity is increased. This could be of value for a more exact determination of differences in regional liver function and, consequently, the estimation of the future remnant liver function.

Induction of sister chromatid exchange in the presence of gadolinium-DTPA and its reduction by dimethyl sulfoxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamazaki, Etsuo; Fukuda, Hozumi; Shibuya, Hitoshi

The authors investigate the frequency of sister chromatid exchange (SCE) after the addition of gadolinium (Gd)-DTPA to venous blood samples. Venous blood was obtained from nonsmokers. Samples were incubated with Gd-DTPA alone or in combination with mitomycin C, cytarabine, and dimethyl sulfoxide (DMSO), and then evaluated for SCEs. The frequency of SCE increased with the concentration of Gd-DTPA and as each chemotherapeutic agent was added. Sister chromatid exchange frequencies were lower when the blood was treated with a combination of Gd-DTPA and DMSO compared with Gd-DTPA alone. The increase in frequency of SCE seen after the addition of Gd-DTPA wasmore » decreased by the addition of DMSO, indicating the production of hydroxyl radicals. The effect likely is dissociation-related. 14 refs., 6 tabs.« less

Magnetic resonance conditional paramagnetic choke for suppression of imaging artifacts during magnetic resonance imaging.

PubMed

Wu, Kevin J; Gregory, T Stan; Boland, Brian L; Zhao, Wujun; Cheng, Rui; Mao, Leidong; Tse, Zion Tsz Ho

2018-06-01

Higher risk patient populations require continuous physiological monitoring and, in some cases, connected life-support systems, during magnetic resonance imaging examinations. While recently there has been a shift toward wireless technology, some of the magnetic resonance imaging devices are still connected to the outside using cabling that could interfere with the magnetic resonance imaging's radio frequency during scanning, resulting in excessive heating. We developed a passive method for radio frequency suppression on cabling that may assist in making some of these devices magnetic resonance imaging compatible. A barrel-shaped strongly paramagnetic choke was developed to suppress induced radio frequency signals which are overlaid onto physiological monitoring leads during magnetic resonance imaging. It utilized a choke placed along the signal lines, with a gadolinium solution core. The choke's magnetic susceptibility was modeled, for a given geometric design, at increasing chelate concentration levels, and measured using a vibrating sample magnetometer. Radio frequency noise suppression versus frequency was quantified with network-analyzer measurements and tested using cabling placed in the magnetic resonance imaging scanner. Temperature-elevation and image-quality reduction due to the device were measured using American Society for Testing and Materials phantoms. Prototype chokes with gadolinium solution cores exhibited increasing magnetic susceptibility, and insertion loss (S21) also showed higher attenuation as gadolinium concentration increased. Image artifacts extending <4 mm from the choke were observed during magnetic resonance imaging, which agreed well with the predicted ∼3 mm artifact from the electrochemical machining simulation. An accompanying temperature increase of <1 °C was observed in the magnetic resonance imaging phantom trial. An effective paramagnetic choke for radio frequency suppression during magnetic resonance imaging was developed

Electrical and Structural Substrate of Arrhythmogenic Right Ventricular Cardiomyopathy Determined Using Noninvasive Electrocardiographic Imaging and Late Gadolinium Magnetic Resonance Imaging.

PubMed

Andrews, Christopher M; Srinivasan, Neil T; Rosmini, Stefania; Bulluck, Heerajnarain; Orini, Michele; Jenkins, Sharon; Pantazis, Antonis; McKenna, William J; Moon, James C; Lambiase, Pier D; Rudy, Yoram

2017-07-01

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a significant cause of sudden cardiac death in the young. Improved noninvasive assessment of ARVC and better understanding of the disease substrate are important for improving patient outcomes. We studied 20 genotyped ARVC patients with a broad spectrum of disease using electrocardiographic imaging (a method for noninvasive cardiac electrophysiology mapping) and advanced late gadolinium enhancement cardiac magnetic resonance scar imaging. Compared with 20 healthy controls, ARVC patients had longer ventricular activation duration (median, 52 versus 42 ms; P =0.007) and prolonged mean epicardial activation-recovery intervals (a surrogate for local action potential duration; median, 275 versus 241 ms; P =0.014). In these patients, we observed abnormal and varied epicardial activation breakthrough locations and regions of nonuniform conduction and fractionated electrograms. Nonuniform conduction and fractionated electrograms were present in the early concealed phase of ARVC. Electrophysiological abnormalities colocalized with late gadolinium enhancement scar, indicating a relationship with structural disease. Premature ventricular contractions were common in ARVC patients with variable initiation sites in both ventricles. Premature ventricular contraction rate increased with exercise, and within anatomic segments, it correlated with prolonged repolarization, electric markers of scar, and late gadolinium enhancement (all P <0.001). Electrocardiographic imaging reveals electrophysiological substrate properties that differ in ARVC patients compared with healthy controls. A novel mechanistic finding is the presence of repolarization abnormalities in regions where ventricular ectopy originates. The results suggest a potential role for electrocardiographic imaging and late gadolinium enhancement in early diagnosis and noninvasive follow-up of ARVC patients. © 2017 American Heart Association, Inc.

Image-guided convection-enhanced delivery of muscimol to the primate brain

PubMed Central

Heiss, John D.; Walbridge, Stuart; Asthagiri, Ashok R.; Lonser, Russell R.

2009-01-01

Object Muscimol is a potent γ-aminobutyric acid-A receptor agonist (GABAA) that temporarily and selectively suppresses neurons. Targeted muscimol-suppression of neuronal structures could provide insight into the pathophysiology and treatment of a variety of neurologic disorders. To determine if muscimol delivered to the brain by convection-enhanced delivery (CED) could be monitored using a co-infused surrogate magnetic resonance (MR)-imaging tracer, we perfused the striata of primates with tritiated muscimol and gadolinium-DTPA. Methods Three primates underwent convective co-infusion of 3H-muscimol (0.8 μM) and gadolinium-DTPA (−5 mM) into the bilateral striata. Primates underwent serial MR-imaging during infusion and animals were sacrificed immediately after infusion. Post-mortem quantitative autoradiography and histological analysis was performed. Results MR-imaging revealed that infusate (tritiated muscimol and gadolinium-DTPA) distribution was clearly discernible from the non-infused parenchyma. Real-time MR-imaging of the infusion revealed the precise region of anatomic perfusion in each animal. Imaging analysis during infusion revealed that the distribution volume of infusate linearly increased (R=0.92) with volume of infusion. Overall, the mean (±S.D.) volume of distribution to volume of infusion ratio was 8.2±1.3. Autoradiographic analysis revealed that MR-imaging of gadolinium-DTPA closely correlated with the distribution of 3H-muscimol and precisely estimated its volume of distribution (mean difference in volume of distribution, 7.4%). Quantitative autoradiograms revealed that muscimol was homogeneously distributed over the perfused region in a square-shaped concentration profile. Conclusions Muscimol can be effectively delivered to clinically relevant volumes of the primate brain. Moreover, the distribution of muscimol can be tracked by co-infusion of gadolinium-DTPA using MR-imaging. The ability to accurately monitor and control the anatomic

Tumor characterization in small animals using magnetic resonance-guided dynamic contrast enhanced diffuse optical tomography

NASA Astrophysics Data System (ADS)

Lin, Yuting; Thayer, Dave; Nalcioglu, Orhan; Gulsen, Gultekin

2011-10-01

We present a magnetic resonance (MR)-guided near-infrared dynamic contrast enhanced diffuse optical tomography (DCE-DOT) system for characterization of tumors using an optical contrast agent (ICG) and a MR contrast agent [Gd-diethylenetriaminepentaacetic acid (DTPA)] in a rat model. Both ICG and Gd-DTPA are injected and monitored simultaneously using a combined MRI-DOT system, resulting in accurate co-registration between two imaging modalities. Fisher rats bearing R3230 breast tumor are imaged using this hybrid system. For the first time, enhancement kinetics of the exogenous contrast ICG is recovered from the DCE-DOT data using MR anatomical a priori information. As tumors grow, they undergo necrosis and the tissue transforms from viable to necrotic. The results show that the physiological changes between viable and necrotic tissue can be differentiated more accurately based on the ICG enhancement kinetics when MR anatomical information is utilized.

Contrast-enhanced computed tomography plus gadolinium-ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging for gross classification of hepatocellular carcinoma.

PubMed

Chen, Chuang; Zhao, Hui; Fu, Xu; Huang, LuoShun; Tang, Min; Yan, XiaoPeng; Sun, ShiQuan; Jia, WenJun; Mao, Liang; Shi, Jiong; Chen, Jun; He, Jian; Zhu, Jin; Qiu, YuDong

2017-05-02

Accurate gross classification through imaging is critical for determination of hepatocellular carcinoma (HCC) patient prognoses and treatment strategies. The present retrospective study evaluated the utility of contrast-enhanced computed tomography (CE-CT) combined with gadolinium-ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (EOB-MRI) for diagnosis and classification of HCCs prior to surgery. Ninety-four surgically resected HCC nodules were classified as simple nodular (SN), SN with extranodular growth (SN-EG), confluent multinodular (CMN), or infiltrative (IF) types. SN-EG, CMN and IF samples were grouped as non-SN. The abilities of the two imaging modalities to differentiate non-SN from SN HCCs were assessed using the EOB-MRI hepatobiliary phase and CE-CT arterial, portal, and equilibrium phases. Areas under the ROC curves for non-SN diagnoses were 0.765 (95% confidence interval [CI]: 0.666-0.846) for CE-CT, 0.877 (95% CI: 0.793-0.936) for EOB-MRI, and 0.908 (95% CI: 0.830-0.958) for CE-CT plus EOB-MRI. Sensitivities, specificities, and accuracies with respect to identification of non-SN tumors of all sizes were 71.4%, 81.6%, and 75.5% for CE-CT; 96.4%, 78.9%, and 89.3% for EOB-MRI; and 98.2%, 84.2%, and 92.5% for CE-CT plus EOB-MRI. These results show that CE-CT combined with EOB-MRI offers a more accurate imaging evaluation for HCC gross classification than either modality alone.

Magnetic Resonance Imaging as a Predictor of Survival Free of Life-Threatening Arrhythmias and Transplantation in Cardiac Sarcoidosis.

PubMed

Ekström, Kaj; Lehtonen, Jukka; Hänninen, Helena; Kandolin, Riina; Kivistö, Sari; Kupari, Markku

2016-05-02

Cardiac magnetic resonance imaging has a key role in today's diagnosis of cardiac sarcoidosis. We set out to investigate whether cardiac magnetic resonance imaging also helps predict outcome in cardiac sarcoidosis. Our work involved 59 patients with cardiac sarcoidosis (38 female, mean age 46±10 years) seen at our hospital since February 2004 and followed up after contrast-enhanced cardiac magnetic resonance imaging. The extent of myocardial late gadolinium enhancement (measured as percentage of left ventricular mass), the volumes and ejection fractions of the left and right ventricles, and the thickness of the basal interventricular septum were determined and analyzed for prognostic significance. By April 2015, 23 patients had reached the study's end point, consisting of a composite of cardiac death (n=3), cardiac transplantation (n=1), and occurrence of life-threatening ventricular tachyarrhythmias (n=19; ventricular fibrillation in 5 and sustained ventricular tachycardia in 14 patients). In univariate analysis, myocardial extent of late gadolinium enhancement predicted event-free survival, as did scar-like thinning (<4 mm) of the basal interventricular septum and the ejection fraction of the right ventricle (P<0.05 for all). In multivariate Cox regression analysis, extent of late gadolinium enhancement was the only independent predictor of outcome events on cardiac magnetic resonance imaging, with a hazard ratio of 2.22 per tertile (95% CI 1.07-4.59). An extent of late gadolinium enhancement >22% (third tertile) had positive and negative predictive values for serious cardiac events of 75% and 76%, respectively. Findings on cardiac magnetic resonance imaging and the extent of myocardial late gadolinium enhancement in particular help predict serious cardiac events in cardiac sarcoidosis. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Comparison of Image Processing Techniques for Nonviable Tissue Quantification in Late Gadolinium Enhancement Cardiac Magnetic Resonance Images.

PubMed

Carminati, M Chiara; Boniotti, Cinzia; Fusini, Laura; Andreini, Daniele; Pontone, Gianluca; Pepi, Mauro; Caiani, Enrico G

2016-05-01

The aim of this study was to compare the performance of quantitative methods, either semiautomated or automated, for left ventricular (LV) nonviable tissue analysis from cardiac magnetic resonance late gadolinium enhancement (CMR-LGE) images. The investigated segmentation techniques were: (i) n-standard deviations thresholding; (ii) full width at half maximum thresholding; (iii) Gaussian mixture model classification; and (iv) fuzzy c-means clustering. These algorithms were applied either in each short axis slice (single-slice approach) or globally considering the entire short-axis stack covering the LV (global approach). CMR-LGE images from 20 patients with ischemic cardiomyopathy were retrospectively selected, and results from each technique were assessed against manual tracing. All methods provided comparable performance in terms of accuracy in scar detection, computation of local transmurality, and high correlation in scar mass compared with the manual technique. In general, no significant difference between single-slice and global approach was noted. The reproducibility of manual and investigated techniques was confirmed in all cases with slightly lower results for the nSD approach. Automated techniques resulted in accurate and reproducible evaluation of LV scars from CMR-LGE in ischemic patients with performance similar to the manual technique. Their application could minimize user interaction and computational time, even when compared with semiautomated approaches.

Are gadolinium contrast agents suitable for gadolinium neutron capture therapy?

PubMed

De Stasio, Gelsomina; Rajesh, Deepika; Casalbore, Patrizia; Daniels, Matthew J; Erhardt, Robert J; Frazer, Bradley H; Wiese, Lisa M; Richter, Katherine L; Sonderegger, Brandon R; Gilbert, Benjamin; Schaub, Sebastien; Cannara, Rachel J; Crawford, John F; Gilles, Mary K; Tyliszczak, Tolek; Fowler, John F; Larocca, Luigi M; Howard, Steven P; Mercanti, Delio; Mehta, Minesh P; Pallini, Roberto

2005-06-01

Gadolinium neutron capture therapy (GdNCT) is a potential treatment for malignant tumors based on two steps: (1) injection of a tumor-specific (157)Gd compound; (2) tumor irradiation with thermal neutrons. The GdNC reaction can induce cell death provided that Gd is proximate to DNA. Here, we studied the nuclear uptake of Gd by glioblastoma (GBM) tumor cells after treatment with two Gd compounds commonly used for magnetic resonance imaging, to evaluate their potential as GdNCT agents. Using synchrotron X-ray spectromicroscopy, we analyzed the Gd distribution at the subcellular level in: (1) human cultured GBM cells exposed to Gd-DTPA or Gd-DOTA for 0-72 hours; (2) intracerebrally implanted C6 glioma tumors in rats injected with one or two doses of Gd-DOTA, and (3) tumor samples from GBM patients injected with Gd-DTPA. In cell cultures, Gd-DTPA and Gd-DOTA were found in 84% and 56% of the cell nuclei, respectively. In rat tumors, Gd penetrated the nuclei of 47% and 85% of the tumor cells, after single and double injection of Gd-DOTA, respectively. In contrast, in human GBM tumors 6.1% of the cell nuclei contained Gd-DTPA. Efficacy of Gd-DTPA and Gd-DOTA as GdNCT agents is predicted to be low, due to the insufficient number of tumor cell nuclei incorporating Gd. Although multiple administration schedules in vivo might induce Gd penetration into more tumor cell nuclei, a search for new Gd compounds with higher nuclear affinity is warranted before planning GdNCT in animal models or clinical trials.

In vitro study of novel gadolinium-loaded liposomes guided by GBI-10 aptamer for promising tumor targeting and tumor diagnosis by magnetic resonance imaging.

PubMed

Gu, Meng-Jie; Li, Kun-Feng; Zhang, Lan-Xin; Wang, Huan; Liu, Li-Si; Zheng, Zhuo-Zhao; Han, Nan-Yin; Yang, Zhen-Jun; Fan, Tian-Yuan

2015-01-01

Novel gadolinium-loaded liposomes guided by GBI-10 aptamer were developed and evaluated in vitro to enhance magnetic resonance imaging (MRI) diagnosis of tumor. Nontargeted gadolinium-loaded liposomes were achieved by incorporating amphipathic material, Gd (III) [N,N-bis-stearylamidomethyl-N'-amidomethyl] diethylenetriamine tetraacetic acid, into the liposome membrane using lipid film hydration method. GBI-10, as the targeting ligand, was then conjugated onto the liposome surface to get GBI-10-targeted gadolinium-loaded liposomes (GTLs). Both nontargeted gadolinium-loaded liposomes and GTLs displayed good dispersion stability, optimal size, and zeta potential for tumor targeting, as well as favorable imaging properties with enhanced relaxivity compared with a commercial MRI contrast agent (CA), gadopentetate dimeglumine. The use of GBI-10 aptamer in this liposomal system was intended to result in increased accumulation of gadolinium at the periphery of C6 glioma cells, where the targeting extracellular matrix protein tenascin-C is overexpressed. Increased cellular binding of GTLs to C6 cells was confirmed by confocal microscopy, flow cytometry, and MRI, demonstrating the promise of this novel delivery system as a carrier of MRI contrast agent for the diagnosis of tumor. These studies provide a new strategy furthering the development of nanomedicine for both diagnosis and therapy of tumor.

In vitro study of novel gadolinium-loaded liposomes guided by GBI-10 aptamer for promising tumor targeting and tumor diagnosis by magnetic resonance imaging

PubMed Central

Gu, Meng-Jie; Li, Kun-Feng; Zhang, Lan-Xin; Wang, Huan; Liu, Li-Si; Zheng, Zhuo-Zhao; Han, Nan-Yin; Yang, Zhen-Jun; Fan, Tian-Yuan

2015-01-01

Novel gadolinium-loaded liposomes guided by GBI-10 aptamer were developed and evaluated in vitro to enhance magnetic resonance imaging (MRI) diagnosis of tumor. Nontargeted gadolinium-loaded liposomes were achieved by incorporating amphipathic material, Gd (III) [N,N-bis-stearylamidomethyl-N′-amidomethyl] diethylenetriamine tetraacetic acid, into the liposome membrane using lipid film hydration method. GBI-10, as the targeting ligand, was then conjugated onto the liposome surface to get GBI-10-targeted gadolinium-loaded liposomes (GTLs). Both nontargeted gadolinium-loaded liposomes and GTLs displayed good dispersion stability, optimal size, and zeta potential for tumor targeting, as well as favorable imaging properties with enhanced relaxivity compared with a commercial MRI contrast agent (CA), gadopentetate dimeglumine. The use of GBI-10 aptamer in this liposomal system was intended to result in increased accumulation of gadolinium at the periphery of C6 glioma cells, where the targeting extracellular matrix protein tenascin-C is overexpressed. Increased cellular binding of GTLs to C6 cells was confirmed by confocal microscopy, flow cytometry, and MRI, demonstrating the promise of this novel delivery system as a carrier of MRI contrast agent for the diagnosis of tumor. These studies provide a new strategy furthering the development of nanomedicine for both diagnosis and therapy of tumor. PMID:26316749

Gadolinium oxide nanoplates with high longitudinal relaxivity for magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Cho, Minjung; Sethi, Richa; Ananta Narayanan, Jeyarama Subramanian; Lee, Seung Soo; Benoit, Denise N.; Taheri, Nasim; Decuzzi, Paolo; Colvin, Vicki L.

2014-10-01

Molecular-based contrast agents for magnetic resonance imaging (MRI) are often characterized by insufficient relaxivity, thus requiring the systemic injection of high doses to induce sufficient contrast enhancement at the target site. In this work, gadolinium oxide (Gd2O3) nanoplates are produced via a thermal decomposition method. The nanoplates have a core diameter varying from 2 to 22 nm, a thickness of 1 to 2 nm and are coated with either an oleic acid bilayer or an octylamine modified poly(acrylic acid) (PAA-OA) polymer layer. For the smaller nanoplates, longitudinal relaxivities (r1) of 7.96 and 47.2 (mM s)-1 were measured at 1.41 T for the oleic acid bilayer and PAA-OA coating, respectively. These values moderately reduce as the size of the Gd2O3 nanoplates increases, and are always larger for the PAA-OA coating. Cytotoxicity studies on human dermal fibroblast cells documented no significant toxicity, with 100% cell viability preserved up to 250 μM for the PAA-OA coated Gd2O3 nanoplates. Given the 10 times increase in longitudinal relaxivity over the commercially available Gd-based molecular agents and the favorable toxicity profile, the 2 nm PAA-OA coated Gd2O3 nanoplates could represent a new class of highly effective T1 MRI contrast agents.Molecular-based contrast agents for magnetic resonance imaging (MRI) are often characterized by insufficient relaxivity, thus requiring the systemic injection of high doses to induce sufficient contrast enhancement at the target site. In this work, gadolinium oxide (Gd2O3) nanoplates are produced via a thermal decomposition method. The nanoplates have a core diameter varying from 2 to 22 nm, a thickness of 1 to 2 nm and are coated with either an oleic acid bilayer or an octylamine modified poly(acrylic acid) (PAA-OA) polymer layer. For the smaller nanoplates, longitudinal relaxivities (r1) of 7.96 and 47.2 (mM s)-1 were measured at 1.41 T for the oleic acid bilayer and PAA-OA coating, respectively. These values

Therapy response assessment after radioembolization of patients with hepatocellular carcinoma--comparison of MR imaging with gadolinium ethoxybenzyl diethylenetriamine penta-acetic acid and gadobutrol.

PubMed

Schelhorn, Juliane; Best, Jan; Reinboldt, Marcus P; Gerken, Guido; Ruhlmann, Marcus; Lauenstein, Thomas C; Antoch, Gerald; Kinner, Sonja

2015-07-01

To compare the utility of gadolinium ethoxybenzyl diethylenetriamine penta-acetic acid (Gd-EOB-DTPA), a liver-specific magnetic resonance (MR) imaging contrast agent, versus gadobutrol for treatment response evaluation of hepatocellular carcinoma (HCC) after radioembolization. This prospective study included 50 patients with HCC undergoing radioembolization. All patients underwent contrast-enhanced computed tomography (CT) and MR imaging with gadobutrol and Gd-EOB-DTPA on 2 consecutive days before radioembolization and 30 days, 90 days, 180 days, and 270 days after radioembolization. The standard of reference indicating tumor progression was CT combined with either α-fetoprotein or γ-glutamyltransferase. Gadobutrol-enhanced MR imaging, Gd-EOB-DTPA-enhanced MR imaging without late phase imaging (Gd-EOB-DTPA-), and Gd-EOB-DTPA-enhanced MR imaging with late phase imaging (Gd-EOB-DTPA+) were evaluated by 2 radiologists in consensus using a 4-point scale: 1 = definitely no tumor progression; 2 = probably no tumor progression; 3 = probably tumor progression; 4 = definitely tumor progression. Diagnostic accuracy was assessed with receiver operating characteristic analysis. Tumor progression was detected in 14 of 82 study visits according to the reference standard. Pairwise comparison of the area under the curve showed a tendency toward a larger area under the curve for Gd-EOB-DTPA+ compared with gadobutrol (P = .056). Sensitivity and specificity were higher in Gd-EOB-DTPA+ (0.929 and 0.971) than in Gd-EOB-DTPA- (0.786 and 0.941) or gadobutrol (0.643 and 0.956). In 2 cases, tumor progression was detected by Gd-EOB-DTPA+ and by an increase in α-fetoprotein, but not by CT, gadobutrol, or Gd-EOB-DTPA-. Gd-EOB-DTPA+ MR imaging was not inferior to gadobutrol-enhanced MR imaging in therapy response evaluation after radioembolization and may allow a more accurate detection of early HCC recurrence in single cases. Copyright © 2015 SIR. Published by Elsevier Inc. All rights

Detection of hepatocellular carcinoma in transgenic mice by Gd-DTPA- and rhodamine 123-conjugated human serum albumin nanoparticles in T1 magnetic resonance imaging.

PubMed

Watcharin, Waralee; Schmithals, Christian; Pleli, Thomas; Köberle, Verena; Korkusuz, Hüdayi; Hübner, Frank; Waidmann, Oliver; Zeuzem, Stefan; Korf, Horst-Werner; Terfort, Andreas; Gelperina, Svetlana; Vogl, Thomas J; Kreuter, Jörg; Piiper, Albrecht

2015-02-10

Nanoparticle (NP)-based contrast agents that enable high resolution anatomic T1-weighted magnetic resonance imaging (MRI) offer the prospect of improving differential diagnosis of liver tumors such as hepatocellular carcinoma (HCC). In the present study, we investigated the possibility of employing novel non-toxic human serum albumin nanoparticles conjugated with Gd-DTPA and rhodamine 123 (Gd-Rho-HSA-NPs) for the detection of HCC by T1-weighted MRI. In addition, the influence of surface coating of the NPs with poloxamine 908, which alters the absorptive behavior of NPs and changes their distribution between the liver and tumor was examined. MRI of transgenic mice with endogenously formed HCCs following intravenous injection of Gd-Rho-HSA-NPs revealed a strong negative contrast of the tumors. Contrasting of the HCCs by NP-enhanced MRI required less Gd as compared to gadolinium-ethoxybenzyl-diethylenetriaminepentaacetic acid-enhanced MRI, which currently provides the most sensitive detection of HCC in patients. Immunohistochemical analyses revealed that the Gd-Rho-HSA-NPs were localized to macrophages, which were - similar to HCC in patients - fewer in number in HCC as compared to the liver tissue, which is in agreement with the negative contrasting of HCC in Gd-Rho-HSA-NP-enhanced MRI. Poloxamine-coated NPs showed lower accumulation in the tumor macrophages and caused a longer lasting enhancement of the MRI signal. These data indicate that Gd-Rho-HSA-NPs enable sensitive detection of HCC by T1-weighted MRI in mice with endogenous HCC through their uptake by macrophages. Poloxamine coating of the NPs delayed the tumor localization of the NPs. Copyright © 2014 Elsevier B.V. All rights reserved.

GADOLINIUM(Gd)-BASED and Ion Oxide Nanoparticle Contrast Agents for Pre-Clinical and Clinical Magnetic Resonance Imaging (mri) Research

NASA Astrophysics Data System (ADS)

Ng, Thian C.

2012-06-01

It is known that one strength of MRI is its excellent soft tissue discrimination. It naturally provides sufficient contrast between the structural differences of normal and pathological tissues, their spatial extent and progression. However, to further extend its applications and enhance even more contrast for clinical studies, various Gadolinium (Gd)-based contrast agents have been developed for different organs (brain strokes, cancer, cardio-MRI, etc). These Gd-based contrast agents are paramagnetic compounds that have strong T1-effect for enhancing the contrast between tissue types. Gd-contrast can also enhance magnetic resonance angiography (CE-MRA) for studying stenosis and for measuring perfusion, vascular susceptibility, interstitial space, etc. Another class of contrast agents makes use of ferrite iron oxide nanoparticles (including Superparamagnetic Ion Oxide (SPIO) and Ultrasmall Superparamagnetic Iron Oxide (USPIO)). These nanoparticles have superior magnetic susceptibility effect and produce a drop in signal, namely in T2*-weighted images, useful for the determination of lymph nodes metastases, angiogenesis and arteriosclerosis plaques.

Low-Molecular-Weight Iron Chelates May Be an Alternative to Gadolinium-based Contrast Agents for T1-weighted Contrast-enhanced MR Imaging.

PubMed

Boehm-Sturm, Philipp; Haeckel, Akvile; Hauptmann, Ralf; Mueller, Susanne; Kuhl, Christiane K; Schellenberger, Eyk A

2018-02-01

Purpose To synthesize two low-molecular-weight iron chelates and compare their T1 contrast effects with those of a commercial gadolinium-based contrast agent for their applicability in dynamic contrast material-enhanced (DCE) magnetic resonance (MR) imaging. Materials and Methods The animal experiments were approved by the local ethics committee. Two previously described iron (Fe) chelates of pentetic acid (Fe-DTPA) and of trans-cyclohexane diamine tetraacetic acid (Fe-tCDTA) were synthesized with stability constants several orders of magnitude higher than those of gadolinium-based contrast agents. The T1 contrast effects of the two chelates were compared with those of gadopentetate dimeglumine in blood serum phantoms at 1.5 T, 3 T, and 7 T. For in vivo studies, a human breast cancer cell line (MDA-231) was implanted in five mice per group. The dynamic contrast effects of the chelates were compared by performing DCE MR imaging with intravenous application of Fe-DTPA or Fe-tCDTA on day 1 and DCE MR imaging in the same tumors with gadopentetate dimeglumine on day 2. Quantitative DCE maps were generated with software and were compared by means of a one-tailed Pearson correlation test. Results Relaxivities in serum (0.94 T at room temperature) of Fe-tCDTA (r1 = 2.2 mmol -1 · sec -1 , r2 = 2.5 mmol -1 · sec -1 ) and Fe-DTPA (r1 = 0.9 mmol -1 · sec -1 , r2 = 0.9 mmol -1 · sec -1 ) were approximately twofold and fivefold lower, respectively, compared with those of gadopentetate dimeglumine (r1 = 4.1 mmol -1 · sec -1 , r2 = 4.8 mmol -1 · sec -1 ). Used at moderately higher concentrations, however, iron chelates generated similar contrast effects at T1-weighted MR imaging in vitro in serum, in vivo in blood, and for DCE MR imaging of breast cancer xenografts. The volume transfer constant values for Fe-DTPA and Fe-tCDTA in the same tumors correlated well with those observed for gadopentetate dimeglumine (Fe-tCDTA Pearson R, 0.99; P = .0003; Fe-DTPA Pearson R, 0.97; P

Gadolinium-conjugated PLA-PEG nanoparticles as liver targeted molecular MRI contrast agent.

PubMed

Chen, Zhijin; Yu, Dexin; Liu, Chunxi; Yang, Xiaoyan; Zhang, Na; Ma, Chunhong; Song, Jibin; Lu, Zaijun

2011-09-01

A nanoparticle magnetic resonance imaging (MRI) contrast agent targeted to liver was developed by conjugation of gadolinium (Gd) chelate groups onto the biocompatible poly(l-lactide)-block-poly (ethylene glycol) (PLA-PEG) nanoparticles. PLA-PEG conjugated with diethylenetriaminopentaacetic acid (DTPA) was used to formulate PLA-PEG-DTPA nanoparticles by solvent diffusion method, and then Gd was loaded onto the nanoparticles by chelated with the unfolding DTPA on the surface of the PLA-PEG-DTPA nanoparticles. The mean size of the nanoparticles was 265.9 ± 6.7 nm. The relaxivity of the Gd-labeled nanoparticles was measured, and the distribution in vivo was evaluated in rats. Compared with conventional contrast agent (Magnevist), the Gd-labeled PLA-PEG nanoparticles showed significant enhancement both on liver targeting ability and imaging signal intensity. The T(1) and T(2) relaxivities per [Gd] of the Gd-labeled nanoparticles was 18.865 mM(-1) s(-1) and 24.863 mM(-1) s(-1) at 3 T, respectively. In addition, the signal intensity in vivo was stronger comparing with the Gd-DTPA and the T(1) weight time was lasting for 4.5 h. The liver targeting efficiency of the Gd-labeled PLA-PEG nanoparticles in rats was 14.57 comparing with Magnevist injection. Therefore, the Gd-labeled nanoparticles showed the potential as targeting molecular MRI contrast agent for further clinical utilization.

MRI (Magnetic Resonance Imaging)

MedlinePlus

... IV in the arm. MRI Research Programs at FDA Magnetic Resonance Imaging (MRI) Safety Electromagnetic Modeling Related ... Resonance Imaging Equipment in Clinical Use (March 2015) FDA/CDER: Information on Gadolinium-Based Contrast Agents Safety ...

Clinical predictors of cardiac magnetic resonance late gadolinium enhancement in patients with atrial fibrillation.

PubMed

Chrispin, Jonathan; Ipek, Esra Gucuk; Habibi, Mohammadali; Yang, Eunice; Spragg, David; Marine, Joseph E; Ashikaga, Hiroshi; Rickard, John; Berger, Ronald D; Zimmerman, Stefan L; Calkins, Hugh; Nazarian, Saman

2017-03-01

This study aims to examine the association of clinical co-morbidities with the presence of left atrial (LA) late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR). Previous studies have established the severity of LA LGE to be associated with atrial fibrillation (AF) recurrence following AF ablation. We sought to determine whether baseline clinical characteristics were associated with LGE extent among patients presenting for an initial AF ablation. The cohort consisted of 179 consecutive patients with no prior cardiac ablation procedures who underwent pre-procedure LGE-CMR. The extent of LA LGE for each patient was calculated using the image intensity ratio, normalized to the mean blood pool intensity, corresponding to a bipolar voltage ≤0.3 mV. The association of LGE extent with baseline clinical characteristics was examined using non-parametric and multivariable models. The mean age of the cohort was 60.9 ± 9.6 years and 128 (72%) were male. In total, 56 (31%) patients had persistent AF. The mean LA volume was 118.4 ± 41.6 mL, and the mean LA LGE extent was 14.1 ± 10.4%. There was no association with any clinical variables with LGE extent by quartiles in the multivariable model. Extent of LGE as a continuous variable was positively, but weakly associated with LA volume in a multivariable model adjusting for age, body mass index, AF persistence, and left ventricular ejection fraction (1.5% scar/mL, P = 0.038). In a cohort of patients presenting for initial AF ablation, the presence of pre-ablation LA LGE extent was weakly, but positively associated with increasing LA volume. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

One-stop-shop preoperative evaluation for living liver donors with gadoxetic acid disodium-enhanced magnetic resonance imaging: efficiency and additional benefit.

PubMed

Xie, Shuangshuang; Liu, Chenhao; Yu, Zichuan; Ren, Tao; Hou, Jiancun; Chen, Lihua; Huang, Lixiang; Cheng, Yue; Ji, Qian; Yin, Jianzhong; Zhang, Longjiang; Shen, Wen

2015-12-01

To explore the efficiency, cost, and time for examination of one-stop-shop gadoxetic acid disodium (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) in preoperative evaluation for parent donors by comparing with multidetector computer tomography combined with conventional MR cholangiopancreatography (MDCT-MRCP). Forty parent donors were evaluated with MDCT-MRCP, and the other 40 sex-, age-, and weight-matched donors with Gd-EOB-DTPA-enhanced MRI. Anatomical variations and graft volume determined by pre- and intra-operative findings, costs and time for imaging were recorded. Image quality was ranked on a 4-point scale and compared between both groups. Gd-EOB-DTPA-enhanced MRI provided better image quality than MDCT-MRCP for the depiction of portal veins and bile ducts by both reviewers (p < 0.05), hepatic veins by one reviewer (p < 0.05), rather hepatic arteries by both reviewers (p < 0.01). Sixty-nine living donors proceeded to liver donation with all anatomical findings accurately confirmed by intra-operative findings. The "in-room" time of Gd-EOB-DTPA-enhanced MRI was 12 min longer than MDCT-MRCP. Gd-EOB-DTPA-enhanced MRI was cheaper than MDCT-MRCP (US$519.72 vs. US$631.85). One-stop-shop Gd-EOB-DTPA-enhanced MRI has similar diagnostic accuracy as MDCT-MRCP and can provide additional benefit in terms of costs and convenience in preoperative evaluation for parent donors. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Target binding improves relaxivity in aptamer-gadolinium conjugates.

PubMed

Bernard, Elyse D; Beking, Michael A; Rajamanickam, Karunanithi; Tsai, Eve C; Derosa, Maria C

2012-12-01

MRI contrast agents (CA) have been heavily used over the past several decades to enhance the diagnostic value of the obtained images. From a design perspective, two avenues to improve the efficacy of contrast agents are readily evident: optimization of magnetic properties of the CA, and optimization of the pharmacokinetics and distribution of the CA in the patient. Contrast agents consisting of DNA aptamer-gadolinium(III) conjugates provide a single system in which these factors can be addressed simultaneously. In this proof-of-concept study, the 15mer thrombin aptamer was conjugated to diethylenetriaminepentaacetic (DTPA) dianhydride to form a monoamide derivative of the linear open-chain chelate present in the commonly used contrast agent Magnevist(®). The stability of the conjugated DNA aptamer-DTPA-Gd(III) chelate in a transmetallation study using Zn(II) was found to be similar to that reported for DTPA-Gd(III). Relaxivity enhancements of 35 ± 4 and 20 ± 1 % were observed in the presence of thrombin compared to a control protein at fields of 9.4 and 1.5 T, respectively. The inclusion of spacers between the aptamer and the DTPA to eliminate possible steric effects was also investigated but not found to improve the relaxation enhancement achieved in comparison to the unaltered aptamer conjugate.

Three-dimensional gadolinium-enhanced magnetic resonance venography in suspected thrombo-occlusive disease of the central chest veins.

PubMed

Kroencke, T J; Taupitz, M; Arnold, R; Fritsche, L; Hamm, B

2001-11-01

To determine the usefulness of high-resolution three-dimensional (3D) gadolinium-enhanced magnetic resonance venography (MRV) in the evaluation of central venous thrombo-occlusive disease of the chest. Prospective study. University hospital. Sixteen consecutive patients with clinically suspected thrombosis of the superior vena cava, subclavian, brachiocephalic/innominate, internal jugular, or axillary veins. Thirteen patients had a neoplasm, two patients had a connective tissue disease, and one patient had a history of strenuous exercise. Twelve of 16 patients had prior central venous catheter placement. MRI was correlated with color-coded duplex sonography (CCDS) in 7 of 16 patients, digital subtraction angiography (DSA) in 3 of 16 patients, and CT in 2 of 16 patients. Contrast-enhanced MRV was performed in a total of 20 examinations. A 3D data set (gradient echo; time to repeat, 4.6 ms; time to echo, 1.8 ms; flip angle, 30 degrees; time of acquisition, 23 s; 512 matrix/64 partitions; slice thickness, 1.5 mm) was acquired in the arterial and venous phase. Overall image quality was assessed on a 5-point scale. The presence, site, and extent of thrombus, as well as presence of an intravascular device, were determined. Overall image quality was rated very good (1 point) in 7 of 16 cases (44%) and good (2 points) in 9 of 16 cases (56%). Thrombus was detected in 16 of 16 patients, and complete extent of disease could be determined in 15 of 16 patients (94%). MRV did not miss any finding obtained by CCDS, DSA, or CT, and provided additional information in 6 of 16 examinations (38%). Contrast-enhanced MRV is a fast and reliable noninvasive procedure with excellent results regarding detection and determination of the extent of thrombo-occlusive disease of the chest veins.

Reaction of gadolinium chelates with ozone and hydroxyl radicals.

PubMed

Cyris, Maike; Knolle, Wolfgang; Richard, Jessica; Dopp, Elke; von Sonntag, Clemens; Schmidt, Torsten C

2013-09-03

Gadolinium chelates are used in increasing amounts as contrast agents in magnetic resonance imaging, and their fate in wastewater treatment has recently become the focus of research. Oxidative processes, in particular the application of ozone, are currently discussed or even implemented for advanced wastewater treatment. However, reactions of the gadolinium chelates with ozone are not yet characterized. In this study, therefore, rate constants with ozone were determined for the three commonly used chelates Gd-DTPA, Gd-DTPA-BMA, and Gd-BT-DO3A, which were found to be 4.8 ± 0.88, 46 ± 2.5, and 24 ± 1.5 M(-1) s(-1), respectively. These low rate constants indicate that a direct reaction with ozone in wastewater is negligible. However, application of ozone in wastewater leads to substantial yields of (•)OH. Different methods have been applied and compared for determination of k((•)OH+Gd chelate). From rate constants determined by pulse radiolysis experiments (k((•)OH+Gd-DTPA) = 2.6 ± 0.2 × 10(9) M(-1) s(-1), k((•)OH+Gd-DTPA-BMA) = 1.9 ± 0.7 × 10(9) M(-1) s(-1), k((•)OH+Gd-BT-DO3A) = 4.3 ± 0.2 × 10(9) M(-1) s(-1)), it is concluded that a reaction in wastewater via (•)OH radicals is feasible. Toxicity has been tested for educt and product mixtures of both reactions. Cytotoxicity (MTT test) and genotoxicity (micronuclei assay) were not detectable.

Liver enhancement in healthy dogs after gadoxetic acid administration during dynamic contrast-enhanced magnetic resonance imaging.

PubMed

Borusewicz, P; Stańczyk, E; Kubiak, K; Spużak, J; Glińska-Suchocka, K; Jankowski, M; Nicpoń, J; Podgórski, P

2018-05-01

Dynamic contrast enhanced (DCE)-magnetic resonance imaging (MRI) consists of acquisition of native baseline images, followed by a series of acquisitions performed during and after administration of a contrast medium. DCE-MRI, in conjunction with hepatobiliary-specific contrast media, such as gadoxetic acid (GD-EOB-DTPA), allows for precise characterisation of the enhancement pattern of the hepatic parenchyma following administration of the contrast agent. The aim of the study was to assess the pattern of temporal resolution contrast enhancement of the hepatic parenchyma following administration of GD-EOB-DTPA and to determine the optimal time window for post-contrast assessment of the liver. The study was carried out on eight healthy beagle dogs. MRI was performed using a 1.5T scanner. The imaging protocol included T1 weighted (T1-W) gradient echo (GRE), T2 weighted (T2-W) turbo spin echo (TSE) and dynamic T1-W GRE sequences. The dynamic T1-W sequence was performed using single 10mm thick slices. Regions of interest (ROIs) were chosen and the signal intensity curves were calculated for quantitative image analysis. The mean time to peak for all dogs was 26min. The plateau phase lasted on average 21min. A gradual decrease in the signal intensity of the hepatic parenchyma was observed in all dogs. A DCE-MRI enhancement pattern of the hepatic parenchyma was evident in dogs following the administration of a GD-EOB-DTPA, establishing baseline data for an optimal time window between 26 and 41min after administration of the contrast agent. Copyright © 2018 Elsevier Ltd. All rights reserved.

Engineered gadolinium-doped carbon dots for magnetic resonance imaging-guided radiotherapy of tumors.

PubMed

Du, Fengyi; Zhang, Lirong; Zhang, Li; Zhang, Miaomiao; Gong, Aihua; Tan, Youwen; Miao, Jiawen; Gong, Yuhua; Sun, Mingzhong; Ju, Huixiang; Wu, Chaoyang; Zou, Shenqiang

2017-03-01

The effectiveness of radiotherapy can decrease due to inaccurate positioning of machinery and inherent radioresistance of tumors. To address this issue, we present a novel theranostic nanoplatform based on gadolinium-doped carbon dots (Gd-doped CDs) designed specifically for magnetic resonance imaging (MRI)-guided radiotherapy of tumors. The Gd-doped CDs (∼18 nm) with dispersibility in water and stable photoluminescence were synthesized via a one-step hydrothermal approach. After tail vein injection of the Gd-doped CDs, they exhibited a relatively long circulation time (∼6 h), enabled efficient passive tumor targeting. Gd-doped CDs accumulate in the kidney and could be cleared out of the body from bladder. Importantly, they exhibited favorable biocompatibility with excellent performance in longitudinal relaxivity rate (r 1 ) of 6.45 mM -1 S -1 and radiosensitization enhancements. These results show that Gd-doped CDs are excellent T 1 contrast agents and radiosensitizers, possessing great promise for MRI-guided radiotherapy of tumors. Copyright © 2016 Elsevier Ltd. All rights reserved.

Convection-enhanced delivery of MANF--volume of distribution analysis in porcine putamen and substantia nigra.

PubMed

Barua, N U; Bienemann, A S; Woolley, M; Wyatt, M J; Johnson, D; Lewis, O; Irving, C; Pritchard, G; Gill, S

2015-10-15

Mesencephalic astrocyte-derived neurotrophic factor (MANF) is a 20kDa human protein which has both neuroprotective and neurorestorative activity on dopaminergic neurons and therefore may have application for the treatment of Parkinson's Disease. The aims of this study were to determine the translational potential of convection-enhanced delivery (CED) of MANF for the treatment of PD by studying its distribution in porcine putamen and substantia nigra and to correlate histological distribution with co-infused gadolinium-DTPA using real-time magnetic resonance imaging. We describe the distribution of MANF in porcine putamen and substantia nigra using an implantable CED catheter system using co-infused gadolinium-DTPA to allow real-time MRI tracking of infusate distribution. The distribution of gadolinium-DTPA on MRI correlated well with immunohistochemical analysis of MANF distribution. Volumetric analysis of MANF IHC staining indicated a volume of infusion (Vi) to volume of distribution (Vd) ratio of 3 in putamen and 2 in substantia nigra. This study confirms the translational potential of CED of MANF as a novel treatment strategy in PD and also supports the co-infusion of gadolinium as a proxy measure of MANF distribution in future clinical studies. Further study is required to determine the optimum infusion regime, flow rate and frequency of infusions in human trials. Copyright © 2015 Elsevier B.V. All rights reserved.

Simple Fabrication of Gd(III)-DTPA-Nanodiamond Particles by Chemical Modification for Use as Magnetic Resonance Imaging (MRI) Contrast Agent

NASA Astrophysics Data System (ADS)

Nakamura, Takako; Ohana, Tsuguyori; Yabuno, Hajime; Kasai, Rumiko; Suzuki, Tetsuya; Hasebe, Terumitsu

2013-01-01

We have developed a simple and useful process for fabricating nanodiamond (ND) particles modified with an organogadolinium moiety by chemical modification for their use as a magnetic resonance imaging (MRI) contrast agent. The introduction of the organogadolinium moiety on the surface of the ND particles was performed by the condensation of ND and diethylenetriaminepentaacetic acid (DTPA) followed by treatment with GdCl3. The modified surfaces were evaluated by X-ray photoelectron spectroscopy, diffuse reflectance Fourier transform infrared spectroscopy, mass spectroscopy, and inductively coupled plasma atomic emission spectroscopy analyses. MRI experiments on the Gd-DTPA-ND particles indicated their high signal intensity on T1-weighted images.

Mechanical delivery of aerosolized gadolinium-DTPA for pulmonary ventilation assessment in MR imaging.

PubMed

Haage, P; Adam, G; Karaagac, S; Pfeffer, J; Glowinski, A; Döhmen, S; Günther, R W

2001-04-01

To evaluate a new technique with mechanical administration of aerosolized gadolinium (Gd)-DTPA for MR visualization of lung ventilation. Ten experimental procedures were performed in six domestic pigs. Gd-DTPA was aerosolized by a small-particle generator. The intubated animals were mechanically aerosolized with the nebulized contrast agent and studied on a 1.5-T MR imager. Respiratory gated T1-weighted turbo spin-echo images were obtained before, during, and after contrast administration. Pulmonary signal intensity (SI) changes were calculated for corresponding regions of both lungs. Homogeneity of aerosol distribution was graded independently by two radiologists. To achieve a comparable SI increase as attained in previous trials that used manual aerosol ventilation, a ventilation period of 20 minutes (formerly 30 minutes) was sufficient. Mean SI changes of 116% were observed after that duration. Contrast delivery was rated evenly distributed in all cases by the reviewers. The feasibility of applying Gd-DTPA as a contrast agent to demonstrate pulmonary ventilation in large animals has been described before. The results of this refined technique substantiate the potential of Gd-based ventilation MR imaging by improving aerosol distribution and shortening the nebulization duration in the healthy lung.

Role of late gadolinium enhancement cardiovascular magnetic resonance in the risk stratification of hypertrophic cardiomyopathy.

PubMed

Ismail, Tevfik F; Jabbour, Andrew; Gulati, Ankur; Mallorie, Amy; Raza, Sadaf; Cowling, Thomas E; Das, Bibek; Khwaja, Jahanzaib; Alpendurada, Francisco D; Wage, Ricardo; Roughton, Michael; McKenna, William J; Moon, James C; Varnava, Amanda; Shakespeare, Carl; Cowie, Martin R; Cook, Stuart A; Elliott, Perry; O'Hanlon, Rory; Pennell, Dudley J; Prasad, Sanjay K

2014-12-01

Myocardial fibrosis identified by late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) in patients with hypertrophic cardiomyopathy (HCM) is associated with adverse cardiovascular events, but its value as an independent risk factor for sudden cardiac death (SCD) is unknown. We investigated the role of LGE-CMR in the risk stratification of HCM. We conducted a prospective cohort study in a tertiary referral centre. Consecutive patients with HCM (n=711, median age 56.3 years, IQR 46.7-66.6; 70.0% male) underwent LGE-CMR and were followed for a median 3.5 years. The primary end point was SCD or aborted SCD. Overall, 471 patients (66.2%) had myocardial fibrosis (median 5.9% of left ventricular mass, IQR: 2.2-13.3). Twenty-two (3.1%) reached the primary end point. The extent but not the presence of fibrosis was a significant univariable predictor of the primary end point (HR per 5% LGE: 1.24, 95% CI 1.06 to 1.45; p=0.007 and HR for LGE: 2.69, 95% CI 0.91 to 7.97; p=0.073, respectively). However, on multivariable analysis, only LV-EF remained statistically significant (HR: 0.92, 95% CI 0.89 to 0.95; p<0.001). For the secondary outcome of cardiovascular mortality/aborted SCD, the presence and the amount of fibrosis were significant predictors on univariable but not multivariable analysis after adjusting for LV-EF and non-sustained ventricular tachycardia. The amount of myocardial fibrosis was a strong univariable predictor of SCD risk. However, this effect was not maintained after adjusting for LV-EF. Further work is required to elucidate the interrelationship between fibrosis and traditional predictors of outcome in HCM. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Dynamic magnetic resonance imaging of the breast: Comparison of gadobutrol vs. Gd-DTPA.

PubMed

Escribano, F; Sentís, M; Oliva, J C; Tortajada, L; Villajos, M; Martín, A; Ganau, S

To compare the pharmacokinetic profile of gadobutrol versus Gd-DTPA in dynamic contrast-enhanced MRI (DCE-MRI) in patients with breast cancer. Secondary objectives included comparing the safety profiles and diagnostic efficacy of the two contrast agents for detecting additional malignant lesions. This retrospective observational study included 400 patients with histologically confirmed breast cancer; 200 underwent DCE-MRI with Gd-DTPA (Magnevist®) and 200 underwent DCE-MRI with gadobutrol (Gadovist®). Pharmacokinetic parameters and signal intensity were analyzed in a region of interest placed in the area within the lesion that had greatest signal intensity in postcontrast sequences. We compared the two groups on pharmacokinetic variables (K trans , K ep , and V e ), time-signal intensity curves, and the number of additional malignant lesions detected. The relative signal intensity (enhancement) was higher with gadobutrol than with Gd-DTPA. Washout was lower with gadobutrol than with Gd-DTPA (46% vs. 58,29%, respectively; p=0,0323). Values for K trans and K ep were higher for gadobutrol (p=0,001). There were no differences in the number of histologically confirmed additional malignant lesions detected (p=0,387). Relative enhancement is greater with gadobutrol, but washout is more pronounced with Gd-DTPA. The number of additional malignant lesions detected did not differ between the two contrast agents. Both contrasts are safe. Copyright © 2017 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

Myocardial Damage Detected by Late Gadolinium Enhancement Cardiovascular Magnetic Resonance Is Associated With Subsequent Hospitalization for Heart Failure

PubMed Central

Wong, Timothy C.; Piehler, Kayla M.; Zareba, Karolina M.; Lin, Kathie; Phrampus, Ashley; Patel, Agam; Moon, James C.; Ugander, Martin; Valeti, Uma; Holtz, Jonathan E.; Fu, Bo; Chang, Chung‐Chou H.; Mathier, Michael; Kellman, Peter; Butler, Javed; Gheorghiade, Mihai; Schelbert, Erik B.

2013-01-01

Background Hospitalization for heart failure (HHF) is among the most important problems confronting medicine. Late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) robustly identifies intrinsic myocardial damage. LGE may indicate inherent vulnerability to HHF, regardless of etiology, across the spectrum of heart failure stage or left ventricular ejection fraction (LVEF). Methods and Results We enrolled 1068 consecutive patients referred for CMR where 448 (42%) exhibited LGE. After a median of 1.4 years (Q1 to Q3: 0.9 to 2.0 years), 57 HHF events occurred, 15 deaths followed HHF, and 43 deaths occurred without antecedent HHF (58 total deaths). Using multivariable Cox regression adjusting for LVEF, heart failure stage, and other covariates, LGE was associated with first HHF after CMR (HR: 2.70, 95% CI: 1.32 to 5.50), death (HR: 2.13, 95% CI: 1.08 to 4.21), or either death or HHF (HR: 2.52, 95% CI: 1.49 to 4.25). Quantifying LGE extent yielded similar results; more LGE equated higher risks. LGE improved model discrimination (IDI: 0.016, 95% CI: 0.005 to 0.028, P=0.002) and reclassification of individuals at risk (continuous NRI: 0.40, 95% CI: 0.05 to 0.70, P=0.024). Adjustment for competing risks of death that shares common risk factors with HHF strengthened the LGE and HHF association (HR: 4.85, 95% CI: 1.40 to 16.9). Conclusions The presence and extent of LGE is associated with vulnerability for HHF, including higher risks of HHF across the spectrum of heart failure stage and LVEF. Even when LVEF is severely decreased, those without LGE appear to fare reasonably well. LGE may enhance risk stratification for HHF and may enhance both clinical and research efforts to reduce HHF through targeted treatment. PMID:24249712

Non‐invasive evaluation of the myocardial substrate of cardiac amyloidosis by gadolinium cardiac magnetic resonance

PubMed Central

Perugini, E; Rapezzi, C; Piva, T; Leone, O; Bacchi‐Reggiani, L; Riva, L; Salvi, F; Lovato, L; Branzi, A; Fattori, R

2006-01-01

Objective To investigate the prevalence and distribution of gadolinium (Gd) enhancement at cardiac magnetic resonance (CMR) imaging in patients with cardiac amyloidosis (CA) and to look for associations with clinical, morphological, and functional features. Patients and design 21 patients with definitely diagnosed CA (nine with immunoglobulin light chain amyloidosis and 12 transthyretin related) underwent Gd‐CMR. Results Gd enhancement was detected in 16 of 21 (76%) patients. Sixty six of 357 (18%) segments were enhanced, more often at the mid ventricular level. Transmural extension of enhancement within each patient significantly correlated with left ventricular (LV) end systolic volume (r  =  0.58). The number of enhanced segments correlated with LV end diastolic volume (r  =  0.76), end systolic volume (r  =  0.6), and left atrial size (r  =  0.56). Segments with > 50% extensive transmural enhancement more often were severely hypokinetic or akinetic (p  =  0.001). Patients with > 2 enhanced segments had significantly lower 12 lead QRS voltage and Sokolow‐Lyon index. No relation was apparent with any other clinical, morphological, functional, or histological characteristics. Conclusion Gd enhancement is common but not universally present in CA, probably due to expansion of infiltrated interstitium. The segmental and transmural distribution of the enhancement is highly variable, and mid‐ventricular regions are more often involved. Enhancement appears to be associated with impaired segmental and global contractility and a larger atrium. PMID:15939726

Proton Relaxivity and Magnetic Hyperthermia Evaluation of Gadolinium Doped Nickel Ferrite Nanoparticles as Potential Theranostic Agents.

PubMed

Yadavalli, Tejabhiram; Raja, Paradeep; Ramaswamy, Shivaraman; Chandrasekharan, Gopalakrishnan; Chennakesavulu, Ramasamy

2017-02-01

This paper outlines the preparation of gadolinium doped nickel ferrite nanoparticles as potential magnetic carriers and longitudinal magnetic resonance imaging contrast agents using hydrothermal method with gadolinium concentration varying from 10% to 40%. A concise effect on the crystal structure was observed at 10% and 20% gadolinium doping, while gadolinium oxide was observed to leach at concentrations exceeding 20%. Further, gadolinium doped nickel ferrites were analyzed for their morphological, magnetic, proton relaxation and magnetic hyperthermia heating properties to understand their potential role as magnetic carrier agents. Low temperature and room temperature magnetic studies conducted on the samples showed comparatively high magnetic saturation with low remanent magnetization. Further, relaxometry studies revealed a high relaxation rate of 6.63 s−1 at a concentration of 0.1 mg/mL. Magnetic hyperthermia studies of the samples at a concentration of 1 mg/mL, assessed that the samples attained a temperature of 68 °C in 240 seconds.

Comparison of Contrast-Enhanced Ultrasound and Gadolinium-Ethoxybenzyl-Diethylenetriamine Pentaacetic Acid-Enhanced MRI for the Diagnosis of Macroscopic Type of Hepatocellular Carcinoma.

PubMed

Iwamoto, Takayuki; Imai, Yasuharu; Kogita, Sachiyo; Igura, Takumi; Sawai, Yoshiyuki; Fukuda, Kazuto; Yamaguchi, Yoshitaka; Matsumoto, Yasushi; Nakahara, Masanori; Morimoto, Osakuni; Seki, Yasushi; Ohashi, Hiroshi; Fujita, Norihiko; Kudo, Masatoshi; Takehara, Tetsuo

We compared the efficacy of contrast-enhanced ultrasound sonography (CEUS) with sonazoid and gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI for the assessment of macroscopic classification of nodular hepatocellular carcinoma (HCC). Seventy-seven consecutive patients with 79 surgically resected HCCs who underwent both preoperative CEUS and Gd-EOB-DTPA-enhanced MRI were enrolled in this retrospective study. Based on the macroscopic diagnosis of resected specimens, nodules were categorized into the simple nodular (SN) and non-SN type HCC. Two hepatologists independently assessed image datasets of the post-vascular phase of CEUS and hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI to compare their diagnostic performance. Gd-EOB-DTPA-enhanced MRI enabled the evaluation of macroscopic classification in a significantly larger number of nodules than CEUS (78/79 (98.7%) vs. 70/79 (88.6%), p < 0.05). Of 70 nodules that could be evaluated by both modalities, 41 and 29 nodules were pathologically categorized as SN and non-SN, respectively. The areas under the receiver operating characteristic curve (AUC) for non-SN did not differ between CEUS and Gd-EOB-DTPA-enhanced MRI (reader 1: 0.748 for CEUS, 0.808 for MRI; reader 2: 0.759 for CEUS, 0.787 for MRI). The AUC of combined CEUS and Gd-EOB-DTPA-enhanced MRI for SN HCC was 0.855 (reader 1) and 0.824 (reader 2), indicating higher AUC values for the combined modalities. The diagnostic performance for macroscopic classification of nodular HCC of CEUS was comparable with that of Gd-EOB-DTPA-enhanced MRI, although some HCCs could not be evaluated by CEUS owing to lower detectability. The combination of the 2 modalities had a more accurate diagnostic performance. © 2016 S. Karger AG, Basel.

Right ventricular involvement in cardiac sarcoidosis demonstrated with cardiac magnetic resonance

PubMed Central

van Geuns, Robert‐Jan; Ainslie, Gillian; Ector, Joris; Heidbuchel, Hein; Crijns, Harry J.G.M.

2017-01-01

Abstract Aims Cardiac involvement in sarcoidosis is reported in up to 30% of patients. Left ventricular involvement demonstrated by contrast‐enhanced cardiac magnetic resonance has been well validated. We sought to determine the prevalence and distribution of right ventricular late gadolinium enhancement in patients diagnosed with pulmonary sarcoidosis. Methods and results We prospectively evaluated 87 patients diagnosed with pulmonary sarcoidosis with contrast‐enhanced cardiac magnetic resonance for right ventricular involvement. Pulmonary artery pressures were non‐invasively evaluated with Doppler echocardiography. Patient characteristics were compared between the groups with and without right ventricular involvement, and right ventricular enhancement was correlated with pulmonary hypertension, ventricular mass, volume, and systolic function. Left ventricular late gadolinium enhancement was demonstrated in 30 patients (34%). Fourteen patients (16%) had right ventricular late gadolinium enhancement, with sole right ventricular enhancement in only two patients. The pattern of right ventricular enhancement consisted of right ventricular outflow tract enhancement in 1 patient, free wall enhancement in 8 patients, ventricular insertion point enhancement in 10 patients, and enhancement of the right side of the interventricular septum in 11 patients. Pulmonary arterial hypertension correlated with the presence of right ventricular enhancement (P < 0.001). Right ventricular enhancement correlated with systolic ventricular dysfunction (P < 0.001), hypertrophy (P = 0.001), and dilation (P < 0.001). Conclusions Right ventricular enhancement was present in 16% of patients diagnosed with pulmonary sarcoidosis and in 48% of patients with left ventricular enhancement. The presence of right ventricular enhancement correlated with pulmonary arterial hypertension, right ventricular systolic dysfunction, hypertrophy, and dilation. PMID:29154434

Evaluation of heart perfusion in patients with acute myocardial infarction using dynamic contrast-enhanced magnetic resonance imaging.

PubMed

Nielsen, Gitte; Fritz-Hansen, Thomas; Dirks, Christina G; Jensen, Gorm B; Larsson, Henrik B W

2004-09-01

To investigate the diagnostic ability of quantitative magnetic resonance imaging (MRI) heart perfusion in acute heart patients, a fast, multislice dynamic contrast-enhanced MRI sequence was applied to patients with acute myocardial infarction. Seven patients with acute transmural myocardial infarction were studied using a Turbo-fast low angle shot (FLASH) MRI sequence to monitor the first pass of an extravascular contrast agent (CA), gadolinium diethylene triamine pentaacetic acid (Gd-DTPA). Quantitation of perfusion, expressed as Ki (mL/100 g/minute), in five slices, each having 60 sectors, provided an estimation of the severity and extent of the perfusion deficiency. Reperfusion was assessed both by noninvasive criteria and by coronary angiography (CAG). The Ki maps clearly delineated the infarction in all patients. Thrombolytic treatment was clearly beneficial in one case, but had no effect in the two other cases. Over the time-course of the study, normal perfusion values were not reestablished following thrombolytic treatment in all cases investigated. This study shows that quantitative MRI perfusion values can be obtained from acutely ill patients following acute myocardial infarction. The technique provides information on both the volume and severity of affected myocardial tissue, enabling the power of treatment regimes to be assessed objectively, and this approach should aid individual patient stratification and prognosis. Copyright 2004 Wiley-Liss, Inc.

Health economic assessment of Gd-EOB-DTPA MRI versus ECCM-MRI and multi-detector CT for diagnosis of hepatocellular carcinoma in China

PubMed Central

He, Xiaoning; Holtorf, Anke-Peggy; Rinde, Harald; Xie, Shuangshuang; Shen, Wen; Hou, Jiancun; Li, Xuehua; Li, Ziping; Lai, Jiaming; Wang, Yuting; Zhang, Lin; Wang, Jian; Li, Xuesong; Ma, Kuansheng; Ye, Feng; Ouyang, Han; Zhao, Hong

2018-01-01

Limited data exists in China on the comparative cost of gadolinium ethoxybenzyl diethylenetriamine magnetic resonance imaging (Gd-EOB-DTPA-MRI) with other imaging techniques. This study compared the total cost of Gd-EOB-DTPA-MRI with multidetector computed tomography (MDCT) and extracellular contrast media–enhanced MRI (ECCM-MRI) as initial imaging procedures in patients with suspected hepatocellular carcinoma (HCC). We developed a decision-tree model on the basis of the Chinese clinical guidelines for HCC, which was validated by clinical experts from China. The model compared the diagnostic accuracy and costs of alternative initial imaging procedures. Compared with MDCT and ECCM-MRI, Gd-EOB-DTPA-MRI imaging was associated with higher rates of diagnostic accuracy, i.e. higher proportions of true positives (TP) and true negatives (TN) with lower false positives (FP). Total diagnosis and treatment cost per patient after the initial Gd-EOB-DTPA-MRI evaluation was similar to MDCT (¥30,360 vs. ¥30,803) and lower than that reported with ECCM-MRI (¥30,360 vs. ¥31,465). Lower treatment cost after initial Gd-EOB-DTPA-MRI was driven by reduced utilization of confirmatory diagnostic procedures and unnecessary treatments. The findings reported that Gd-EOB-DTPA-MRI offered higher diagnostic accuracy compared with MDCT and ECCM-MRI at a comparable cost, which indicates Gd-EOB-DTPA-MRI could be the preferred initial imaging procedure for the diagnosis of HCC in China. PMID:29324837

Selective modification of NMR relaxation time in human colorectal carcinoma by using gadolinium-diethylenetriaminepentaacetic acid conjugated with monoclonal antibody 19-9.

PubMed Central

Curtet, C; Tellier, C; Bohy, J; Conti, M L; Saccavini, J C; Thedrez, P; Douillard, J Y; Chatal, J F; Koprowski, H

1986-01-01

Monoclonal antibody 19-9 (mAb 19-9) against human colon adenocarcinoma was conjugated with gadolinium X diethylenetriaminepentaacetic acid (Gd X DTPA) and used as a contrast agent in nuclear magnetic resonance (NMR) in an effort to improve tumor target selectivity in nude mice. The data indicate that Gd X DTPA-mAb 19-9 in solution decreased the T1 relaxation of water protons at 90 MHz in direct proportion to the gadolinium concentration, and this effect was greater than in Gd X DTPA solutions. T1 relaxation time at 90 MHz, measured in tumors removed from nude mice 24 hr after injection of Gd X DTPA-mAb 19-9 (Gd, 20 mumol/kg; 16 DTPA molecules per mAb molecule), was significantly decreased (by 15%) as compared with the control group. Similar results were obtained in tumors from mice injected with Gd X DTPA-mAb 19-9 solutions in which Gd was used at 2, 6, or 10 mumol/kg (16 DTPA molecules per mAb molecule). These doses are lower than those commonly used for Gd X DTPA (10-100 mumol/kg) as contrast agent. Tumor localization by the Gd X DTPA-mAb 19-9 complex containing radioactive Gd (0.3 microCi/microgram of 153Gd) to confirm scintigraphy revealed significant concentrations of the complex (5% of the injected dose per gram of tissue) in the tumor. Scan images recorded in planar scintigraphy at day 5 showed good visualization of tumors. Images PMID:3459174

Plasmon-Induced Magnetic Resonance Enhanced Raman Spectroscopy.

PubMed

Chen, Shu; Zhang, Yuejiao; Shih, Tien-Mo; Yang, Weimin; Hu, Shu; Hu, Xiaoyan; Li, Jianfeng; Ren, Bin; Mao, Bingwei; Yang, Zhilin; Tian, Zhongqun

2018-04-11

Plasmon-induced magnetic resonance has shown great potentials in optical metamaterials, chemical (bio)-sensing, and surface-enhanced spectroscopies. Here, we have theoretically and experimentally revealed (1) a correspondence of the strongest near-field response to the far-field scattering valley and (2) a significant improvement in Raman signals of probing molecules by the plasmon-induced magnetic resonance. These revelations are accomplished by designing a simple and practical metallic nanoparticle-film plasmonic system that generates magnetic resonances at visible-near-infrared frequencies. Our work may provide new insights for understanding the enhancement mechanism of various plasmon-enhanced spectroscopies and also helps further explore light-matter interactions at the nanoscale.

Comparative evaluation of three-dimensional Gd-EOB-DTPA-enhanced MR fusion imaging with CT fusion imaging in the assessment of treatment effect of radiofrequency ablation of hepatocellular carcinoma.

PubMed

Makino, Yuki; Imai, Yasuharu; Igura, Takumi; Hori, Masatoshi; Fukuda, Kazuto; Sawai, Yoshiyuki; Kogita, Sachiyo; Fujita, Norihiko; Takehara, Tetsuo; Murakami, Takamichi

2015-01-01

To assess the feasibility of fusion of pre- and post-ablation gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (Gd-EOB-DTPA-MRI) to evaluate the effects of radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC), compared with similarly fused CT images This retrospective study included 67 patients with 92 HCCs treated with RFA. Fusion images of pre- and post-RFA dynamic CT, and pre- and post-RFA Gd-EOB-DTPA-MRI were created, using a rigid registration method. The minimal ablative margin measured on fusion imaging was categorized into three groups: (1) tumor protruding outside the ablation zone boundary, (2) ablative margin 0-<5.0 mm beyond the tumor boundary, and (3) ablative margin ≥5.0 mm beyond the tumor boundary. The categorization of minimal ablative margins was compared between CT and MR fusion images. In 57 (62.0%) HCCs, treatment evaluation was possible both on CT and MR fusion images, and the overall agreement between them for the categorization of minimal ablative margin was good (κ coefficient = 0.676, P < 0.01). MR fusion imaging enabled treatment evaluation in a significantly larger number of HCCs than CT fusion imaging (86/92 [93.5%] vs. 62/92 [67.4%], P < 0.05). Fusion of pre- and post-ablation Gd-EOB-DTPA-MRI is feasible for treatment evaluation after RFA. It may enable accurate treatment evaluation in cases where CT fusion imaging is not helpful.

Green Synthesis of Sub-10 nm Gadolinium-Based Nanoparticles for Sparkling Kidneys, Tumor, and Angiogenesis of Tumor-Bearing Mice in Magnetic Resonance Imaging.

PubMed

Zhang, Bingbo; Yang, Weitao; Yu, Jiani; Guo, Weisheng; Wang, Jun; Liu, Shiyuan; Xiao, Yi; Shi, Donglu

2017-02-01

Gadolinium (Gd)-based nanoparticles are known for their high potential in magnetic resonance imaging (MRI). However, further MRI applications of these nanoparticles are hampered by their relatively large sizes resulting in poor organ/tumor targeting. In this study, ultrafine sub-10 nm and biocompatible Gd-based nanoparticles are synthesized in a bioinspired, environmentally benign, and straightforward fashion. This novel green synthetic strategy is developed for growing dextran-coated Gd-based nanoparticles (GdNPs@Dex). The as-prepared GdNPs@Dex is not only biocompatible but also stable with a sub-10 nm size. It exhibits higher longitudinal and transverse relaxivities in water (r 1 and r 2 values of 5.43 and 7.502 s -1 × 10 -3 m -1 of Gd 3+ , respectively) than those measured for Gd-DTPA solution (r 1 and r 2 values of 3.42 and 3.86 s -1 × 10 -3 m -1 of Gd 3+ , respectively). In vivo dynamic T 1 -weighted MRI in tumor-bearing mice shows GdNPs@Dex can selectively target kidneys and tumor, in addition to liver and spleen. GdNPs@Dex is found particularly capable for determining the tumor boundary with clearly enhanced tumor angiogenesis. GdNPs@Dex is also found cleared from body gradually mainly via hepatobiliary and renal processing with no obvious systemic toxicity. With this green synthesis strategy, the sub-10 nm GdNPs@Dex presents promising potentials for translational biomedical imaging applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Superparamagnetic And Paramagnetic MRI Contrast Agents: Application Of Rapid Magnetic Resonance Imaging To Assess Renal Function

NASA Astrophysics Data System (ADS)

Carvlin, Mark J.; Renshaw, Perry F.; Arger, Peter; Kundel, Harold L.; Dougherty, Larry; Axel, Leon; Kassab, Eleanor; Moore, Bethanne

1988-06-01

The paramagnetic chelate complex, gadolinium-diethylene-triamine-pentaacetic acid, Gd-DTPA, and superparamagnetic particles, such as those composed of dextran coated magnetite, function as magnetic resonance contrast agents by changing the relaxation rates, 1/T1 and 1/T2. The effects that these agents have upon MR signal intensity are determined by: the inherent biophysical properties of the tissue being imaged, the concentration of the contrast agent and the data acquisition scheme (pulse sequence parameters) employed. Following the time course of MR signal change in the first minutes after the injection of contrast agent(s) allows a dynamic assessment of organ functions in a manner analogous to certain nuclear medicine studies. In order to study renal function, sequential MR fast scan images, gradient echo (TR=35/TE=7 msec, flip angle=25 degrees), were acquired, one every 12 seconds, after intravenous injection of Gd-DTPA and/or dextran-magnetite. Gd-DTPA, which is freely filtered at the glomerulus and is neither secreted nor reabsorbed, provides information concerning renal perfusion, glomerular filtration and tubular concentrating ability. Dextran-magnetite (200 A diameter), which is primarily contained within the intravascular space shortly after injection, provides information on blood flow to and distribution within the kidney. The MR signal change observed after administration of contrast agents varied dramatically depending upon the agents injected and the imaging parameters used. Hence a broad range of physiolgic processes may be described using these techniques, i.e. contrast agent enhanced functional MR examinations.

Coupling Gd-DTPA with a bispecific, recombinant protein anti-EGFR-iRGD complex improves tumor targeting in MRI

PubMed Central

XIN, XIAOYAN; SHA, HUIZI; SHEN, JINGTAO; ZHANG, BING; ZHU, BIN; LIU, BAORUI

2016-01-01

Recombinant anti-epidermal growth factor receptor-internalizing arginine-glycine-aspartic acid (anti-EGFR single-domain antibody fused with iRGD peptide) protein efficiently targets the EGFR extracellular domain and integrin αvβ/β5, and shows a high penetration into cells. Thus, this protein may improve penetration of conjugated drugs into the deep zone of gastric cancer multicellular 3D spheroids. In the present study, a novel tumor-targeting contrast agent for magnetic resonance imaging (MRI) was developed, by coupling gadolinium-diethylene triamine pentaacetate (Gd-DTPA) with the bispecific recombinant anti-EGFR-iRGD protein. The anti-EGFR-iRGD protein was extracted from Escherichia coli and Gd was loaded onto the recombinant protein by chelation using DTPA anhydride. Single-targeting agent anti-EGFR-DTPA-Gd, which served as the control, was also prepared. The results of the present study showed that anti-EGFR-iRGD-DTPA-Gd exhibited no significant cyto toxicity to human gastric carcinoma cells (BGC-823) under the experimental conditions used. Compared with a conventional contrast agent (Magnevist), anti-EGFR-iRGD-DTPA-Gd showed higher T1 relaxivity (10.157/mM/sec at 3T) and better tumor-targeting ability. In addition, the signal intensity and the area under curve for the enhanced signal time in tumor, in vivo, were stronger than Gd-DTPA alone or the anti-EGFR-Gd control. Thus, Gd-labelled anti-EGFR-iRGD has potential as a tumor-targeting contrast agent for improved MRI. PMID:27035336

Combining diffusion-weighted MRI with Gd-EOB-DTPA-enhanced MRI improves the detection of colorectal liver metastases.

PubMed

Koh, D-M; Collins, D J; Wallace, T; Chau, I; Riddell, A M

2012-07-01

To compare the diagnostic accuracy of gadolinium-ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced MRI, diffusion-weighted MRI (DW-MRI) and a combination of both techniques for the detection of colorectal hepatic metastases. 72 patients with suspected colorectal liver metastases underwent Gd-EOB-DTPA MRI and DW-MRI. Images were retrospectively reviewed with unenhanced T(1) and T(2) weighted images as Gd-EOB-DTPA image set, DW-MRI image set and combined image set by two independent radiologists. Each lesion detected was scored for size, location and likelihood of metastasis, and compared with surgery and follow-up imaging. Diagnostic accuracy was compared using receiver operating characteristics and interobserver agreement by kappa statistics. 417 lesions (310 metastases, 107 benign) were found in 72 patients. For both readers, diagnostic accuracy using the combined image set was higher [area under the curve (Az)=0.96, 0.97] than Gd-EOB-DTPA image set (Az=0.86, 0.89) or DW-MRI image set (Az=0.93, 0.92). Using combined image set improved identification of liver metastases compared with Gd-EOB-DTPA image set (p<0.001) or DW-MRI image set (p<0.001). There was very good interobserver agreement for lesion classification (κ=0.81-0.88). Combining DW-MRI with Gd-EOB-DTPA-enhanced T(1) weighted MRI significantly improved the detection of colorectal liver metastases.

Right ventricular involvement in cardiac sarcoidosis demonstrated with cardiac magnetic resonance.

PubMed

Smedema, Jan-Peter; van Geuns, Robert-Jan; Ainslie, Gillian; Ector, Joris; Heidbuchel, Hein; Crijns, Harry J G M

2017-11-01

Cardiac involvement in sarcoidosis is reported in up to 30% of patients. Left ventricular involvement demonstrated by contrast-enhanced cardiac magnetic resonance has been well validated. We sought to determine the prevalence and distribution of right ventricular late gadolinium enhancement in patients diagnosed with pulmonary sarcoidosis. We prospectively evaluated 87 patients diagnosed with pulmonary sarcoidosis with contrast-enhanced cardiac magnetic resonance for right ventricular involvement. Pulmonary artery pressures were non-invasively evaluated with Doppler echocardiography. Patient characteristics were compared between the groups with and without right ventricular involvement, and right ventricular enhancement was correlated with pulmonary hypertension, ventricular mass, volume, and systolic function. Left ventricular late gadolinium enhancement was demonstrated in 30 patients (34%). Fourteen patients (16%) had right ventricular late gadolinium enhancement, with sole right ventricular enhancement in only two patients. The pattern of right ventricular enhancement consisted of right ventricular outflow tract enhancement in 1 patient, free wall enhancement in 8 patients, ventricular insertion point enhancement in 10 patients, and enhancement of the right side of the interventricular septum in 11 patients. Pulmonary arterial hypertension correlated with the presence of right ventricular enhancement (P < 0.001). Right ventricular enhancement correlated with systolic ventricular dysfunction (P < 0.001), hypertrophy (P = 0.001), and dilation (P < 0.001). Right ventricular enhancement was present in 16% of patients diagnosed with pulmonary sarcoidosis and in 48% of patients with left ventricular enhancement. The presence of right ventricular enhancement correlated with pulmonary arterial hypertension, right ventricular systolic dysfunction, hypertrophy, and dilation. © 2017 The Authors. ESC Heart Failure published by John Wiley & Sons Ltd on behalf of

Diagnosis of Bell palsy with gadolinium magnetic resonance imaging.

PubMed

Becelli, R; Perugini, M; Carboni, A; Renzi, G

2003-01-01

Bell palsy is a condition resulting from a peripheral edematous compression on the nervous fibers of the facial nerve. This pathological condition often has clinical characteristics of no importance and spontaneously disappears in a short time in a high percentage of cases. Facial palsy concerning cranial nerve VII can also be caused by other conditions such as mastoid fracture, acoustic neurinoma, tumor spread to the temporal lobe (e.g., cholesteatoma), neoformation of the parotid gland, Melkersson-Rosenthal syndrome, and Ramsay-Hunt syndrome. Therefore, it is important to adopt an accurate diagnostic technique allowing the rapid detection of Bell palsy and the exclusion of causes of facial paralysis requiring surgical treatment. Magnetic resonance imaging (MRI) with medium contrast of the skull shows a marked increase in revealing lesions, even of small dimensions, inside the temporal bone and at the cerebellopontine angle. The authors present a clinical case to show the important role played by gadolinium MRI in reaching a diagnosis of Bell palsy in the differential diagnosis of the various conditions that determine paralysis of the facial nerve and in selecting the most suitable treatment or surgery to be adopted.

Chlorophyll-a analogues conjugated with aminobenzyl-DTPA as potential bifunctional agents for magnetic resonance imaging and photodynamic therapy.

PubMed

Li, Guolin; Slansky, Adam; Dobhal, Mahabeer P; Goswami, Lalit N; Graham, Andrew; Chen, Yihui; Kanter, Peter; Alberico, Ronald A; Spernyak, Joseph; Morgan, Janet; Mazurchuk, Richard; Oseroff, Allan; Grossman, Zachary; Pandey, Ravindra K

2005-01-01

A clinically relevant photosensitizer, 3-devinyl-3-(1-hexyloxyethyl)pyropheophorbide-a (HPPH, a chlorophyll-a derivative), was conjugated with Gd(III)-aminobenzyl-diethylenetriaminepentaacetic acid (DTPA), an experimental magnetic resonance (MR) imaging agent. In vivo reflectance spectroscopy confirmed tumor uptake of HPPH-aminobenzyl-Gd(III)-DTPA conjugate was higher than free HPPH administered intraveneously (iv) to C3H mice with subcutaneously (sc) implanted radiation-induced fibrosarcoma (RIF) tumor cells. In other experiments, Sprague-Dawley (SD) rats with sc implanted Ward Colon Carcinoma cells yielded markedly increased MR signal intensities from tumor regions-of-interest (ROIs) 24 h post-iv injection of HPPH-aminobenzyl-Gd(III)-DTPA conjugate as compared to unconjugated HPPH. In both in vitro (RIF tumor cells) and in vivo (mice bearing RIF tumors and rats bearing Ward Colon tumors) the conjugate produced significant increases in tumor conspicuity at 1.5 T and retained therapeutic efficacy following PDT. Also synthesized were a series of novel bifunctional agents containing two Gd(III) atoms per HPPH molecule that remained tumor-avid and PDT-active and yielded improved MR tumor conspicuity compared to their corresponding mono-Gd(III) analogues. Administered iv at a MR imaging dose of 10 micromol/kg, these conjugates produced severe skin phototoxicity. However, by replacing the hexyl group of the pyropheophorbide-a with a tri(ethylene glycol) monomethyl ether (PEG-methyl ether), these conjugates produced remarkable MR tumor enhancement at 8 h post-iv injection, significant tumoricidal activity (80% of mice were tumor-free on day 90), and reduced skin phototoxicity compared to their corresponding hexyl ether analogues. The poor water-solubility characteristic of these conjugates was resolved by incorporation into a liposomal formulation. This paper presents the synthesis of tumor-avid contrast enhancing agents for MR imaging and thus represents an important

Stability and trapping of magnetic resonance imaging contrast agents during high-intensity focused ultrasound ablation therapy.

PubMed

Hijnen, Nicole M; Elevelt, Aaldert; Grüll, Holger

2013-07-01

The purpose of this study was to investigate the use of Gd-DTPA shortly before magnetic resonance guided high-intensity focused ultrasound MR-HIFU thermal ablation therapy with respect to dissociation, trapping, and long-term deposition of gadolinium (Gd) in the body. Magnetic resonance-HIFU ablation treatment was conducted in vivo on both rat muscle and subcutaneous tumor (9L glioma) using a clinical 3T MR-HIFU system equipped with a small-animal coil setup. A human equivalent dose of gadopentetate dimeglumine (Gd-DTPA) (0.6 mmol/kg of body weight) was injected via a tail vein catheter just before ablation (≤5 minutes). Potential trapping of the contrast agent in the ablated area was visualized through the acquisition of R1 maps of the target location before and after therapy. The animals were sacrificed 2 hours or 14 days after the injection (n = 4 per group, a total of 40 animals). Subsequently, the Gd content in the tissue and carcass was determined using inductively coupled plasma techniques to investigate the biodistribution. Temporal trapping of Gd-DTPA in the coagulated tissue was observed on the R1 maps acquired within 2 hours after the ablation, an effect confirmed by the inductively coupled plasma analysis (3 times more Gd was found in the treated muscle volume than in the control muscle tissue). Two weeks after the therapy, the absolute amount of Gd present in the coagulated tissue was low compared with the amount present in the kidneys 14 days after the injection (ablated muscle, 0.009% ± 0.002% ID/g; kidney, 0.144% ± 0.165% ID/g). There was no significant increase in Gd content in the principal target organs for translocated Gdions (liver, spleen, and bone) or in the entire carcasses between the HIFU- and sham-treated animals. Finally, an in vivo relaxivity of 4.6 mmols was found in the HIFU-ablated volume, indicating intact Gd-DTPA. Magnetic resonance-HIFU treatment does not induce the dissociation of Gd-DTPA. In small-tissue volumes, no

Preparation and Evaluation of Multiple Nanoemulsions Containing Gadolinium (III) Chelate as a Potential Magnetic Resonance Imaging (MRI) Contrast Agent.

PubMed

Sigward, Estelle; Corvis, Yohann; Doan, Bich-Thuy; Kindsiko, Kadri; Seguin, Johanne; Scherman, Daniel; Brossard, Denis; Mignet, Nathalie; Espeau, Philippe; Crauste-Manciet, Sylvie

2015-09-01

The objective was to develop, characterize and assess the potentiality of W1/O/W2 self-emulsifying multiple nanoemulsions to enhance signal/noise ratio for Magnetic Resonance Imaging (MRI). For this purpose, a new formulation, was designed for encapsulation efficiency and stability. Various methods were used to characterize encapsulation efficiency ,in particular calorimetric methods (Differential Scanning Calorimetry (DSC), thermogravimetry analysis) and ultrafiltration. MRI in vitro relaxivities were assessed on loaded DTPA-Gd multiple nanoemulsions. Characterization of the formulation, in particular of encapsulation efficiency was a challenge due to interactions found with ultrafiltration method. Thanks to the specifically developed DSC protocol, we were able to confirm the formation of multiple nanoemulsions, differentiate loaded from unloaded nanoemulsions and measure the encapsulation efficiency which was found to be quite high with a 68% of drug loaded. Relaxivity studies showed that the self-emulsifying W/O/W nanoemulsions were positive contrast agents, exhibiting higher relaxivities than those of the DTPA-Gd solution taken as a reference. New self-emulsifying multiple nanoemulsions that were able to load satisfactory amounts of contrasting agent were successfully developed as potential MRI contrasting agents. A specific DSC protocol was needed to be developed to characterize these complex systems as it would be useful to develop these self-formation formulations.

Extracellular diffusion quantified by magnetic resonance imaging during rat C6 glioma cell progression.

PubMed

Song, G; Luo, T; Dong, L; Liu, Q

2017-07-03

Solution reflux and edema hamper the convection-enhanced delivery of the standard treatment for glioma. Therefore, a real-time magnetic resonance imaging (MRI) method was developed to monitor the dosing process, but a quantitative analysis of local diffusion and clearance parameters has not been assessed. The objective of this study was to compare diffusion into the extracellular space (ECS) at different stages of rat C6 gliomas, and analyze the effects of the extracellular matrix (ECM) on the diffusion process. At 10 and 20 days, after successful glioma modeling, gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) was introduced into the ECS of rat C6 gliomas. Diffusion parameters and half-life of the reagent were then detected using MRI, and quantified according to the mathematical model of diffusion. The main ECM components [chondroitin sulfate proteoglycans (CSPGs), collagen IV, and tenascin C] were detected by immunohistochemical and immunoblot analyses. In 20-day gliomas, Gd-DTPA diffused more slowly and derived higher tortuosity, with lower clearance rate and longer half-life compared to 10-day gliomas. The increased glioma ECM was associated with different diffusion and clearance parameters in 20-day rat gliomas compared to 10-day gliomas. ECS parameters were altered with C6 glioma progression from increased ECM content. Our study might help better understand the glioma microenvironment and provide benefits for interstitial drug delivery to treat brain gliomas.

MRI contrast agent for targeting glioma: interleukin-13 labeled liposome encapsulating gadolinium-DTPA

PubMed Central

Liu, Xiaoli; Madhankumar, Achuthamangalam B.; Miller, Patti A.; Duck, Kari A.; Hafenstein, Susan; Rizk, Elias; Slagle-Webb, Becky; Sheehan, Jonas M.; Connor, James R.; Yang, Qing X.

2016-01-01

Background Detection of glioma with MRI contrast agent is limited to cases in which the blood-brain barrier (BBB) is compromised as contrast agents cannot cross the BBB. Thus, an early-stage infiltrating tumor is not detectable. Interleukin-13 receptor alpha 2 (IL-13Rα2), which has been shown to be overexpressed in glioma, can be used as a target moiety. We hypothesized that liposomes conjugated with IL-13 and encapsulating MRI contrast agent are capable of passing through an intact BBB and producing MRI contrast with greater sensitivity. Methods The targeted MRI contrast agent was created by encapsulating Magnevist (Gd-DTPA) into liposomes conjugated with IL-13 and characterized by particle size distribution, cytotoxicity, and MRI relaxivity. MR image intensity was evaluated in the brain in normal mice post injection of Gd-DTPA and IL-13-liposome-Gd-DTPA one day apart. The specificity for glioma detection by IL-13-liposome-Gd-DTPA was demonstrated in an intracranial glioma mouse model and validated histologically. Results The average size of IL-13-liposome-Gd-DTPA was 137 ± 43 nm with relaxivity of 4.0 ± 0.4 L/mmole-s at 7 Tesla. No significant cytotoxicity was observed with MTS assay and serum chemistry in mice. The MRI signal intensity was enhanced up to 15% post injection of IL-13-liposome-Gd-DTPA in normal brain tissue following a similar time course as that for the pituitary gland outside of the BBB. MRI enhanced by IL-13-liposome-Gd-DTPA detected small tumor masses in addition to those seen with Magnevist-enhanced MRI. Conclusions IL-13-liposome-Gd-DTPA is able to pass through the uncompromised BBB and detect an early stage glioma that cannot be seen with conventional contrast-enhanced MRI. PMID:26519740

Tracing gadolinium-based contrast agents from surface water to drinking water by means of speciation analysis.

PubMed

Birka, Marvin; Wehe, Christoph A; Hachmöller, Oliver; Sperling, Michael; Karst, Uwe

2016-04-01

In recent decades, a significant amount of anthropogenic gadolinium has been released into the environment as a result of the broad application of contrast agents for magnetic resonance imaging (MRI). Since this anthropogenic gadolinium anomaly has also been detected in drinking water, it has become necessary to investigate the possible effect of drinking water purification on these highly polar microcontaminats. Therefore, a novel highly sensitive method for speciation analysis of gadolinium is presented. For that purpose, the hyphenation of hydrophilic interaction liquid chromatography (HILIC) and inductively coupled plasma-mass spectrometry (ICP-MS) was employed. In order to enhance the detection power, sample introduction was carried out by ultrasonic nebulization. In combination with a novel HILIC method using a diol-based stationary phase, it was possible to achieve superior limits of detection for frequently applied gadolinium-based contrast agents below 20pmol/L. With this method, the contrast agents Gd-DTPA, Gd-DOTA and Gd-BT-DO3A were determined in concentrations up to 159pmol/L in samples from several waterworks in a densely populated region of Germany alongside the river Ruhr as well as from a waterworks near a catchment lake. Thereby, the direct impact of anthropogenic gadolinium species being present in the surface water on the amount of anthropogenic gadolinium in drinking water was shown. There was no evidence for the degradation of contrast agents, the release of Gd(3+) or the presence of further Gd species. Copyright © 2016 Elsevier B.V. All rights reserved.

The Prognostic Value of Late Gadolinium-Enhanced Cardiac Magnetic Resonance Imaging in Nonischemic Dilated Cardiomyopathy: A Review and Meta-Analysis.

PubMed

Becker, Marthe A J; Cornel, Jan H; van de Ven, Peter M; van Rossum, Albert C; Allaart, Cornelis P; Germans, Tjeerd

2018-04-13

This review and meta-analysis reviews the prognostic value of cardiac magnetic resonance (CMR) in nonischemic dilated cardiomyopathy (DCM). Late gadolinium-enhanced (LGE) CMR is a noninvasive method to determine the underlying cause of DCM and previous studies reported the prognostic value of the presence of LGE to identify patients at risk of major adverse cardiovascular events. PubMed was searched for studies describing the prognostic implication of LGE in patients with DCM for the specified endpoints cardiovascular mortality, major ventricular arrhythmic events including appropriate implantable cardioverter-defibrillator therapy, rehospitalization for heart failure, and left ventricular reverse remodeling. Data from 34 studies were included, with a total of 4,554 patients. Contrast enhancement was present in 44.8% of DCM patients. Patients with LGE had increased cardiovascular mortality (odds ratio [OR]: 3.40; 95% confidence interval [CI]: 2.04 to 5.67), ventricular arrhythmic events (OR: 4.52; 95% CI: 3.41 to 5.99), and rehospitalization for heart failure (OR: 2.66; 95% CI: 1.67 to 4.24) compared with those without LGE. Moreover, the absence of LGE predicted left ventricular reverse remodeling (OR: 0.15; 95% CI: 0.06 to 0.36). The presence of LGE on CMR substantially worsens prognosis for adverse cardiovascular events in DCM patients, and the absence indicates left ventricular reverse remodeling. Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Clinical usefulness of the ablative margin assessed by magnetic resonance imaging with Gd-EOB-DTPA for radiofrequency ablation of hepatocellular carcinoma.

PubMed

Koda, Masahiko; Tokunaga, Shiho; Okamoto, Toshiaki; Hodozuka, Masanori; Miyoshi, Kennichi; Kishina, Manabu; Fujise, Yuki; Kato, Jun; Matono, Tomomitsu; Sugihara, Takaaki; Oyama, Kenji; Hosho, Keiko; Okano, Jun-ichi; Murawaki, Yoshikazu; Kakite, Suguru; Yamashita, Eijiro

2015-12-01

The aim of this study was to investigate the feasibility of ablative margin (AM) grading by magnetic resonance imaging (MRI) with Gd-EOB-DTPA administered prior to radiofrequency ablation (RFA), and to identify factors for achieving a sufficient AM and predictors for local tumor progression. A total of 124 hepatocellular carcinomas (HCCs) were treated by RFA after Gd-EOB-DTPA administration. MRI and enhanced CT were performed within seven hours and one month after RFA. The AM assessment was categorized using three grades: AM (+), low-intensity area with continuous high-intensity rim; AM zero, low-intensity area with discontinuous high-intensity rim; and AM (-), low-intensity area extends beyond the high-intensity rim. Patients were followed and local tumor progression was observed. AM (+), AM zero, AM (-), and indeterminate were found in 34, 33, 26, and 31 nodules, respectively. The overall agreement rate between MRI and enhanced CT for the diagnosis of AM was 56.8%. The κ coefficient was 0.326 (p<0.001), indicating moderate agreement. Multivariate logistic regression analysis showed that a significant factor for the achievement of AM (+) on MRI was no contiguous vessels. The cumulative local tumor progression rates (0% at 1, 2, and 3 years) in 33 AM (+) nodules were significantly lower than those (3.6%, 11.5%, and 18.3% at 1, 2, and 3 years respectively) in 32 AM zero nodules. A multivariate Cox proportional hazards model identified tumor size as an independent predictor for local tumor progression. Gd-EOB-DTPA-MRI enabled an early assessment of RFA effectiveness in the majority ofHCC nodules. Local tumor progression was not detected in AM (+) nodules during the follow-up. Copyright © 2015 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Evaluation of intraaxial enhancing brain tumors on magnetic resonance imaging: intraindividual crossover comparison of gadobenate dimeglumine and gadopentetate dimeglumine for visualization and assessment, and implications for surgical intervention.

PubMed

Kuhn, Matthew J; Picozzi, Piero; Maldjian, Joseph A; Schmalfuss, Ilona M; Maravilla, Kenneth R; Bowen, Brian C; Wippold, Franz J; Runge, Val M; Knopp, Michael V; Wolansky, Leo J; Gustafsson, Lars; Essig, Marco; Anzalone, Nicoletta

2007-04-01

The goal in this article was to compare 0.1 mmol/kg doses of gadobenate dimeglumine (Gd-BOPTA) and gadopentetate dimeglumine, also known as gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA), for enhanced magnetic resonance (MR) imaging of intraaxial brain tumors. Eighty-four patients with either intraaxial glioma (47 patients) or metastasis (37 patients) underwent two MR imaging examinations at 1.5 tesla, one with Gd-BOPTA as the contrast agent and the other with Gd-DTPA. The interval between fully randomized contrast medium administrations was 2 to 7 days. The T1-weighted spin echo and T2-weighted fast spin echo images were acquired before administration of contrast agents and T1-weighted spin echo images were obtained after the agents were administered. Acquisition parameters and postinjection acquisition times were identical for the two examinations in each patient. Three experienced readers working in a fully blinded fashion independently evaluated all images for degree and quality of available information (lesion contrast enhancement, lesion border delineation, definition of disease extent, visualization of the lesion's internal structures, global diagnostic preference) and quantitative enhancement (that is, the extent of lesion enhancement after contrast agent administration compared with that seen before its administration [hereafter referred to as percent enhancement], lesion/brain ratio, and contrast/noise ratio). Differences were tested with the Wilcoxon signed-rank test. Reader agreement was assessed using kappa statistics. Significantly better diagnostic information/imaging performance (p < 0.0001, all readers) was obtained with Gd-BOPTA for all visualization end points. Global preference for images obtained with Gd-BOPTA was expressed for 42 (50%), 52 (61.9%), and 56 (66.7%) of 84 patients (readers 1, 2, and 3, respectively) compared with images obtained with Gd-DTPA contrast in four (4.8%), six (7.1%), and three (3.6%) of 84 patients. Similar

Effects of iodinated contrast agent, xylocaine and gadolinium concentration on the signal emitted in magnetic resonance arthrography: a samples study*

PubMed Central

da Silva, Yvana Lopes Pinheiro; Costa, Rita Zanlorensi Visneck; Pinho, Kátia Elisa Prus; Ferreira, Ricardo Rabello; Schuindt, Sueliton Miyamoto

2015-01-01

Objective To investigate the effects of dilution of paramagnetic contrast agent with iodinated contrast and xylocaine on the signal intensity during magnetic resonance arthrography, and to improve the paramagnetic contrast agent concentration utilized in this imaging modality. Materials and Methods Samples specially prepared for the study with three different concentrations of paramagnetic contrast agent diluted in saline, iodinated contrast agent and xylocaine were imaged with fast spin echo T1-weighted sequences with fat saturation. The samples were placed into flasks and graphical analysis of the signal intensity was performed as a function of the paramagnetic contrast concentration. Results As compared with samples of equal concentrations diluted only with saline, the authors have observed an average signal intensity decrease of 20.67% for iodinated contrast agent, and of 28.34% for xylocaine. However, the increased gadolinium concentration in the samples caused decrease in signal intensity with all the dilutions. Conclusion Minimizing the use of iodinated contrast media and xylocaine and/or the use of a gadolinium concentration of 2.5 mmol/L diluted in saline will improve the sensitivity of magnetic resonance arthrography. PMID:25987746

Preclinical evaluation of Gd-DTPA and gadomelitol as contrast agents in DCE-MRI of cervical carcinoma interstitial fluid pressure.

PubMed

Hompland, Tord; Ellingsen, Christine; Rofstad, Einar K

2012-11-22

High interstitial fluid pressure (IFP) in the primary tumor is associated with poor disease-free survival in locally advanced cervical carcinoma. A noninvasive assay is needed to identify cervical cancer patients with highly elevated tumor IFP because these patients may benefit from particularly aggressive treatment. It has been suggested that dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) with gadolinium diethylene-triamine penta-acetic acid (Gd-DTPA) as contrast agent may provide useful information on the IFP of cervical carcinomas. In this preclinical study, we investigated whether DCE-MRI with contrast agents with higher molecular weights (MW) than Gd-DTPA would be superior to Gd-DTPA-based DCE-MRI. CK-160 human cervical carcinoma xenografts were subjected to DCE-MRI with Gd-DTPA (MW of 0.55 kDa) or gadomelitol (MW of 6.5 kDa) as contrast agent before tumor IFP was measured invasively with a Millar SPC 320 catheter. The DCE-MRI was carried out at a spatial resolution of 0.23 × 0.23 × 2.0 mm³ and a time resolution of 14 s by using a 1.5-T whole-body scanner and a slotted tube resonator transceiver coil constructed for mice. Parametric images were derived from the DCE-MRI recordings by using the Tofts iso-directional transport model and the Patlak uni-directional transport model. When gadomelitol was used as contrast agent, significant positive correlations were found between the parameters of both pharmacokinetic models and tumor IFP. On the other hand, significant correlations between DCE-MRI-derived parameters and IFP could not be detected with Gd-DTPA as contrast agent. Gadomelitol is a superior contrast agent to Gd-DTPA in DCE-MRI of the IFP of CK-160 cervical carcinoma xenografts. Clinical studies attempting to develop DCE-MRI-based assays of the IFP of cervical carcinomas should involve contrast agents with higher MW than Gd-DTPA.

Diagnostic value of Gd-EOB-DTPA-enhanced MR cholangiography in non-invasive detection of postoperative bile leakage.

PubMed

Kul, Melahat; Erden, Ayşe; Düşünceli Atman, Ebru

2017-04-01

To assess the diagnostic value of dynamic T 1 weighted (T1w) gadolinium ethoxybenzyl diethylenetriamine penta-acetic acid (Gd-EOB-DTPA)-enhanced MR cholangiography (MRC) for the detection of active bile leaks. A total of 28 patients with suspected biliary leakage who underwent routine T 2 weighted (T2w) MRC and T1w GD-EOB-DTPA-enhanced MRC at our institution from February 2013 to June 2016 were included in this study. The image sets were retrospectively analyzed in consensus by three radiologists. T1w Gd-EOB-DTPA-enhanced MRC findings were correlated with clinical data, follow-up examinations and findings of invasive/surgical procedures. Patients with positive bile leak findings in Gd-EOB-DTPA-enhanced MRC were divided into hepatobiliary phase (HBP) (20-30 min) and delayed phase (DP) (60-390 min) group according to elapsed time between Gd-EOB-DTPA injection and initial bile leak findings in MRC images. These groups were compared in terms of laboratory test results (total bilirubin, liver enzymes) and the presence of bile duct dilatation in T2w MRC images. In each patient, visualization of bile ducts was sufficient in the HBP. The accuracy, sensitivity and specificity of dynamic Gd-EOB-DTPA-enhanced T1w MRC in the detection of biliary leaks were 92.9%, 90.5% and 100%, respectively (p < 0.001). 19 of 28 patients had bile leak findings in T1w Gd-EOB-DTPA-enhanced MRC [HBP group: N = 7 (36.8%), DP group: N = 12 (63.2%)]. There was no statistically significant difference in terms of laboratory test results and the presence of bile duct dilatation between HBP and DP group (p > 0.05). Three patients, each of them in DP group, showed normal laboratory test results and bile duct diameters. Dynamic T1w Gd-EOB-DTPA-enhanced MRC is a useful non-invasive diagnostic tool to detect bile leak. Advances in knowledge: Prolonged DP imaging may be required for bile leak detection even if visualization of biliary tree is sufficient in HBP and liver function tests

Evaluation of biliary ductal anatomy in potential living liver donors: comparison between MRCP and Gd-EOB-DTPA-enhanced MRI.

PubMed

Santosh, D; Goel, A; Birchall, I W; Kumar, A; Lee, K H; Patel, V H; Low, G

2017-10-01

To compare magnetic resonance cholangiopancreatography (MRCP) and Gd-EOB-DTPA-enhanced MRI in the evaluation of the biliary anatomy in potential living liver donors (LLDs). A retrospective study was conducted in a tertiary care liver transplant center after obtaining ethics and institutional approvals. A total of 42 potential LLD MRI examinations were performed between November 2013 and March 2016. All patients underwent a standard MRI protocol which included MRCP and Gd-EOB-DTPA-enhanced MRI sequences in a single session. Three abdominal MR radiologists independently reviewed the studies and completed a customized data collection sheet for each MR sequence. The readers subjectively scored the bile duct visualization on each MR sequence on a Likert scale and classified the biliary anatomic configuration. Statistical analysis was performed using intraclass correlation coefficient and the McNemar Chi-square (χ 2 ) test. The 42 potential LLDs included 22 males and 20 females with an age range of 18-60 years. There was 'good' or 'excellent' inter-reader agreement on either MRI examination for the visualization of the first- and second-order ducts and the majority of third-order ducts. 'Good' inter-reader agreement on Gd-EOB-DTPA-enhanced MRI and 'fair' inter-reader agreement on MRCP was noted for the left third-order medial duct. There was significantly better visualization of the cystic duct, left hepatic duct, and right second-order ducts on Gd-EOB-DTPA-enhanced MRI compared with MRCP. A 12.6% improvement in classifying the biliary branch pattern was also observed on Gd-EOB-DTPA-enhanced MRI compared with MRCP (P = 0.03). Gd-EOB-DTPA-enhanced MRI provides additional diagnostic confidence over MRCP in the evaluation of the biliary ductal anatomy in potential LLDs.

Health economic evaluation of Gd-EOB-DTPA MRI vs ECCM-MRI and multi-detector computed tomography in patients with suspected hepatocellular carcinoma in Thailand and South Korea.

PubMed

Lee, Jeong-Min; Kim, Myeong-Jin; Phongkitkarun, Sith; Sobhonslidsuk, Abhasnee; Holtorf, Anke-Peggy; Rinde, Harald; Bergmann, Karsten

2016-08-01

The effectiveness of treatment decisions and economic outcomes of using gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (Gd-EOB-DTPA-MRI) were compared with extracellular contrast media-enhanced MRI (ECCM-MRI) and multi-detector computed tomography (MDCT) as initial procedures in patients with suspected hepatocellular carcinoma (HCC) in South Korea and Thailand. A decision-tree model simulated the clinical pathway for patients with suspected HCC from the first imaging procedure to a confirmed treatment decision. Input data (probabilities and resource consumptions) were estimated and validated by clinical experts. Costs for diagnostic alternatives and related treatment options were derived from published sources, taking into account both payer's and hospital's perspectives. All experts from Korea and Thailand agreed that Gd-EOB-DTPA-MRI yields the highest diagnostic certainty and minimizes the need for additional confirmatory diagnostic procedures in HCC. In Korea, from the payer's perspective, total cost was USD $3087/patient to reach a confirmed treatment decision using Gd-EOB-DTPA-MRI (vs $3205/patient for MDCT and $3403/patient for ECCM-MRI). From the hospital's perspective, Gd-EOB-DTPA-MRI incurred the lowest cost ($2289/patient vs $2320/patient and $2528/patient, respectively). In Thailand, Gd-EOB-DTPA-MRI was the least costly alternative for the payer ($702/patient vs $931/patient for MDCT and $873/patient for ECCM-MRI). From the hospital's perspective, costs were $1106/patient, $1178/patient, and $1087/patient for Gd-EOB-DTPA-MRI, MDCT, and ECCM-MRI, respectively. Gd-EOB-DTPA-MRI as an initial imaging procedure in patients with suspected HCC provides better diagnostic certainty and relevant statutory health insurance cost savings in Thailand and Korea, compared with ECCM-MRI and MDCT.

Quantitative mapping of solute accumulation in a soil-root system by magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Haber-Pohlmeier, S.; Vanderborght, J.; Pohlmeier, A.

2017-08-01

Differential uptake of water and solutes by plant roots generates heterogeneous concentration distributions in soils. Noninvasive observations of root system architecture and concentration patterns therefore provide information about root water and solute uptake. We present the application of magnetic resonance imaging (MRI) to image and monitor root architecture and the distribution of a tracer, GdDTPA2- (Gadolinium-diethylenetriaminepentacetate) noninvasively during an infiltration experiment in a soil column planted with white lupin. We show that inversion recovery preparation within the MRI imaging sequence can quantitatively map concentrations of a tracer in a complex root-soil system. Instead of a simple T1 weighting, the procedure is extended by a wide range of inversion times to precisely map T1 and subsequently to cover a much broader concentration range of the solute. The derived concentrations patterns were consistent with mass balances and showed that the GdDTPA2- tracer represents a solute that is excluded by roots. Monitoring and imaging the accumulation of the tracer in the root zone therefore offers the potential to determine where and by which roots water is taken up.

Grading of inflammatory disease activity in the sacroiliac joints with magnetic resonance imaging: comparison between short-tau inversion recovery and gadolinium contrast-enhanced sequences.

PubMed

Madsen, Karen Berenth; Egund, Niels; Jurik, Anne Grethe

2010-02-01

We investigated the potential concordance of 2 different magnetic resonance (MR) sequences - short-tau inversion recovery (STIR) and fat-saturated T1-weighted spin-echo after application of gadolinium (Gd) contrast medium to detect active bone marrow abnormalities at the sacroiliac joints (SIJ) in patients with spondyloarthritis (SpA). Blinded and using the Danish scoring method, we evaluated transaxial MR images of the 2 sequences in 40 patients with SpA with disease duration of 3-14 years. Both the cartilaginous and ligamentous portions of the SIJ were analyzed. There was a significant positive correlation between the activity scores obtained by STIR and Gd-enhanced sequences (p < 0.0001). Agreement in the detection of bone marrow abnormalities occurred in 60 of the 80 joints, 35 with and 25 without signs of active disease. Discordance with STIR-positive marrow activity scores occurred in only 11 joints; Gd-enhanced positive scores in 9 joints. The STIR sequence detected remnants of marrow activity in the periphery of chronic fatty replacement not seen or partly obscured on the Gd sequence. Small subchondral enhancing lesions may not be scored on the STIR sequence, mostly because of reduced image resolution. Active bone marrow abnormalities were detected nearly equally well with STIR and Gd-enhanced fat-suppressed T1 sequences in patients with SpA, with STIR being most sensitive to visualize active abnormalities in the periphery of chronic changes.

MRI contrast agent for targeting glioma: interleukin-13 labeled liposome encapsulating gadolinium-DTPA.

PubMed

Liu, Xiaoli; Madhankumar, Achuthamangalam B; Miller, Patti A; Duck, Kari A; Hafenstein, Susan; Rizk, Elias; Slagle-Webb, Becky; Sheehan, Jonas M; Connor, James R; Yang, Qing X

2016-05-01

Detection of glioma with MRI contrast agent is limited to cases in which the blood-brain barrier (BBB) is compromised as contrast agents cannot cross the BBB. Thus, an early-stage infiltrating tumor is not detectable. Interleukin-13 receptor alpha 2 (IL-13Rα2), which has been shown to be overexpressed in glioma, can be used as a target moiety. We hypothesized that liposomes conjugated with IL-13 and encapsulating MRI contrast agent are capable of passing through an intact BBB and producing MRI contrast with greater sensitivity. The targeted MRI contrast agent was created by encapsulating Magnevist (Gd-DTPA) into liposomes conjugated with IL-13 and characterized by particle size distribution, cytotoxicity, and MRI relaxivity. MR image intensity was evaluated in the brain in normal mice post injection of Gd-DTPA and IL-13-liposome-Gd-DTPA one day apart. The specificity for glioma detection by IL-13-liposome-Gd-DTPA was demonstrated in an intracranial glioma mouse model and validated histologically. The average size of IL-13-liposome-Gd-DTPA was 137 ± 43 nm with relaxivity of 4.0 ± 0.4 L/mmole-s at 7 Tesla. No significant cytotoxicity was observed with MTS assay and serum chemistry in mice. The MRI signal intensity was enhanced up to 15% post injection of IL-13-liposome-Gd-DTPA in normal brain tissue following a similar time course as that for the pituitary gland outside of the BBB. MRI enhanced by IL-13-liposome-Gd-DTPA detected small tumor masses in addition to those seen with Magnevist-enhanced MRI. IL-13-liposome-Gd-DTPA is able to pass through the uncompromised BBB and detect an early stage glioma that cannot be seen with conventional contrast-enhanced MRI. © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Synthesis and evaluation of novel polysaccharide-Gd-DTPA compounds as contrast agent for MRI

NASA Astrophysics Data System (ADS)

Sun, Guoying; Feng, Jianghua; Jing, Fengying; Pei, Fengkui; Liu, Maili

2003-09-01

Macromolecular conjugates of two kinds of natural polysaccharides, that from Panax quinquefolium linn (PQPS) and Ganoderma applanatum pat (GAPS), with gadolinium-diethylenetriaminepenta-acetic acid (Gd-DTPA) have been synthesized and characterized by means of FTIR, elementary analysis and ICP-AES. Their stability was investigated by competition study with Ca 2+, EDTA (ethylenediaminetetraacetic acid) and DTPA. Polysaccharide-bound complexes exhibit T1 relaxivities of 1.5-1.7 times that of Gd-DTPA in D 2O at 25°C and 9.4 T. MR imaging of Sprague-Dawley (SD) rats showed remarkable enhancement in rat liver and kidney after i.v. injection of these two complexes: liver parenchyma 60.9±5.6%, 57.8±7.4% at 65-85 min; kidney 144.9±14.5%, 199.9±25.4% at 10-30 min for PQPS-Gd-DTPA, GAPS-Gd-DTPA at gadolinium dose of 0.083 and 0.082 mmol/kg, respectively. Our preliminary in vivo and in vitro study indicates that the two kinds of polysaccharide-bound complexes are potential tissue-specific contrast agents for MRI.

Improved dark blood late gadolinium enhancement (DB-LGE) imaging using an optimized joint inversion preparation and T2 magnetization preparation.

PubMed

Basha, Tamer A; Tang, Maxine C; Tsao, Connie; Tschabrunn, Cory M; Anter, Elad; Manning, Warren J; Nezafat, Reza

2018-01-01

To develop a dark blood-late gadolinium enhancement (DB-LGE) sequence that improves scar-blood contrast and delineation of scar region. The DB-LGE sequence uses an inversion pulse followed by T 2 magnetization preparation to suppress blood and normal myocardium. Time delays inserted after preparation pulses and T 2 -magnetization-prep duration are used to adjust tissue contrast. Selection of these parameters was optimized using numerical simulations and phantom experiments. We evaluated DB-LGE in 9 swine and 42 patients (56 ± 14 years, 33 male). Improvement in scar-blood contrast and overall image quality was subjectively evaluated by two independent readers (1 = poor, 4 = excellent). The signal ratios among scar, blood, and myocardium were compared. Simulations and phantom studies demonstrated that simultaneous nulling of myocardium and blood can be achieved by selecting appropriate timing parameters. The scar-blood contrast score was significantly higher for DB-LGE (P < 0.001) with no significant difference in overall image quality (P > 0.05). Scar-blood signal ratios for DB-LGE versus LGE were 5.0 ± 2.8 versus 1.5 ± 0.5 (P < 0.001) for patients, and 2.2 ± 0.7 versus 1.0 ± 0.4 (P = 0.0023) for animals. Scar-myocardium signal ratios were 5.7 ± 2.9 versus 6.3 ± 2.6 (P = 0.35) for patients, and 3.7 ± 1.1 versus 4.1 ± 2.0 (P = 0.60) for swine. The DB-LGE sequence simultaneously reduces normal myocardium and blood signal intensity, thereby enhancing scar-blood contrast while preserving scar-myocardium contrast. Magn Reson Med 79:351-360, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

Complex imaging features of accidental cerebral intraventricular gadolinium administration.

PubMed

Nayak, Nita B; Huang, Jimmy C; Hathout, Gasser M; Shaba, Wisam; El-Saden, Suzie M

2013-05-01

Gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) is a contrast agent commonly used for enhancing MRI. In this paper, the authors report on 2 cases of postoperative inadvertent administration of Gd-DTPA directly into a ventriculostomy tubing side port that was mistaken for intravenous tubing. Both cases demonstrated a low signal on MRI throughout the ventricular system and dependent portions of the subarachnoid spaces, which was originally believed to be CSF with areas of T1 shortening in the nondependent portions of the subarachnoid spaces, and misinterpreted as basal leptomeningeal enhancement and meningitis. The authors propose that the appearance of profound T1 hypointensity within the ventricles and diffuse susceptibility artifact along the ependyma is pathognomonic of intraventricular Gd-DTPA and should be recognized.

Separation of Gd-humic complexes and Gd-based magnetic resonance imaging contrast agent in river water with QAE-Sephadex A-25 for the fractionation analysis.

PubMed

Matsumiya, Hiroaki; Inoue, Hiroto; Hiraide, Masataka

2014-10-01

Gadolinium complexed with naturally occurring, negatively charged humic substances (humic and fulvic acids) was collected from 500 mL of sample solution onto a column packed with 150 mg of a strongly basic anion-exchanger (QAE-Sephadex A-25). A Gd-based magnetic resonance imaging contrast agent (diethylenetriamine-N,N,N',N″,N″-pentaacetato aquo gadolinium(III), Gd-DTPA(2-)) was simultaneously collected on the same column. The Gd-DTPA complex was desorbed by anion-exchange with 50mM tetramethylammonium sulfate, leaving the Gd-humic complexes on the column. The Gd-humic complexes were subsequently dissociated with 1M nitric acid to desorb the humic fraction of Gd. The two-step desorption with small volumes of the eluting agents allowed the 100-fold preconcentration for the fractionation analysis of Gd at low ng L(-1) levels by inductively coupled plasma-mass spectrometry (ICP-MS). On the other hand, Gd(III) neither complexed with humic substances nor DTPA, i.e., free species, was not sorbed on the column. The free Gd in the effluent was preconcentrated 100-fold by a conventional solid-phase extraction with an iminodiacetic acid-type chelating resin and determined by ICP-MS. The proposed analytical fractionation method was applied to river water samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Upconverting rare-earth nanoparticles with a paramagnetic lanthanide complex shell for upconversion fluorescent and magnetic resonance dual-modality imaging

NASA Astrophysics Data System (ADS)

Wang, Yan; Ji, Lei; Zhang, Bingbo; Yin, Peihao; Qiu, Yanyan; Song, Daqian; Zhou, Juying; Li, Qi

2013-05-01

Multi-modal imaging based on multifunctional nanoparticles is a promising alternative approach to improve the sensitivity of early cancer diagnosis. In this study, highly upconverting fluorescence and strong relaxivity rare-earth nanoparticles coated with paramagnetic lanthanide complex shells and polyethylene glycol (PEGylated UCNPs@DTPA-Gd3+) are synthesized as dual-modality imaging contrast agents (CAs) for upconverting fluorescent and magnetic resonance dual-modality imaging. PEGylated UCNPs@DTPA-Gd3+ with sizes in the range of 32-86 nm are colloidally stable. They exhibit higher longitudinal relaxivity and transverse relaxivity in water (r1 and r2 values are 7.4 and 27.8 s-1 per mM Gd3+, respectively) than does commercial Gd-DTPA (r1 and r2 values of 3.7 and 4.6 s-1 per mM Gd3+, respectively). They are found to be biocompatible. In vitro cancer cell imaging shows good imaging contrast of PEGylated UCNPs@DTPA-Gd3+. In vivo upconversion fluorescent imaging and T1-weighted MRI show excellent enhancement of both fluorescent and MR signals in the livers of mice administered PEGylated UCNPs@DTPA-Gd3+. All the experimental results indicate that the synthesized PEGylated UCNPs@DTPA-Gd3+ present great potential for biomedical upconversion of fluorescent and magnetic resonance dual-modality imaging applications.

Deep learning enables reduced gadolinium dose for contrast-enhanced brain MRI.

PubMed

Gong, Enhao; Pauly, John M; Wintermark, Max; Zaharchuk, Greg

2018-02-13

better (n = 20, P = 0.039) motion-artifact suppression was noted in the synthesized images. The noninferiority test rejects the inferiority of the synthesized to true full-dose images for image quality (95% CI: -14-9%), artifacts suppression (95% CI: -5-20%), and contrast enhancement (95% CI: -13-6%). With the proposed deep learning method, gadolinium dose can be reduced 10-fold while preserving contrast information and avoiding significant image quality degradation. 3 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2018. © 2018 International Society for Magnetic Resonance in Medicine.

Gadolinium-Conjugated Gold Nanoshells for Multimodal Diagnostic Imaging and Photothermal Cancer Therapy

PubMed Central

Coughlin, Andrew J.; Ananta, Jeyarama S.; Deng, Nanfu; Larina, Irina V.; Decuzzi, Paolo

2014-01-01

Multimodal imaging offers the potential to improve diagnosis and enhance the specificity of photothermal cancer therapy. Toward this goal, we have engineered gadolinium-conjugated gold nanoshells and demonstrated that they enhance contrast for magnetic resonance imaging, X-Ray, optical coherence tomography, reflectance confocal microscopy, and two-photon luminescence. Additionally, these particles effectively convert near-infrared light to heat, which can be used to ablate cancer cells. Ultimately, these studies demonstrate the potential of gadolinium-nanoshells for image-guided photothermal ablation. PMID:24115690

Molecular imaging of alpha v beta3 integrin expression in atherosclerotic plaques with a mimetic of RGD peptide grafted to Gd-DTPA.

PubMed

Burtea, Carmen; Laurent, Sophie; Murariu, Oltea; Rattat, Dirk; Toubeau, Gérard; Verbruggen, Alfons; Vansthertem, David; Vander Elst, Luce; Muller, Robert N

2008-04-01

The integrin alpha v beta3 is highly expressed in atherosclerotic plaques by medial and intimal smooth muscle cells and by endothelial cells of angiogenic microvessels. In this study, we have assessed non-invasive molecular magnetic resonance imaging (MRI) of plaque-associated alpha v beta3 integrin expression on transgenic ApoE-/- mice with a low molecular weight peptidomimetic of Arg-Gly-Asp (mimRGD) grafted to gadolinium diethylenetriaminepentaacetate (Gd-DTPA-g-mimRGD). The analogous compound Eu-DTPA-g-mimRGD was employed for an in vivo competition experiment and to confirm the molecular targeting. The specific interaction of mimRGD conjugated to Gd-DTPA or to 99mTc-DTPA with alpha v beta3 integrin was furthermore confirmed on Jurkat T lymphocytes. The mimRGD was synthesized and conjugated to DTPA. DTPA-g-mimRGD was complexed with GdCl3.6H2O, EuCl3.6H2O, or with [99mTc(CO)3(H2O)3]+. MRI evaluation was performed on a 4.7 T Bruker imaging system. Blood pharmacokinetics of Gd-DTPA-g-mimRGD were assessed in Wistar rats and in c57bl/6j mice. The presence of angiogenic blood vessels and the expression of alpha v beta3 integrin were confirmed in aorta specimens by immunohistochemistry. Gd-DTPA-g-mimRGD produced a strong enhancement of the external structures of the aortic wall and of the more profound layers (possibly tunica media and intima). The aortic lumen seemed to be restrained and distorted. Pre-injection of Eu-DTPA-g-mimRGD diminished the Gd-DTPA-g-mimRGD binding to atherosclerotic plaque and confirmed the specific molecular targeting. A slower blood clearance was observed for Gd-DTPA-g-mimRGD, as indicated by a prolonged elimination half-life and a diminished total clearance. The new compound is potentially useful for the diagnosis of vulnerable atherosclerotic plaques and of other pathologies characterized by alpha v beta3 integrin expression, such as cancer and inflammation. The delayed blood clearance, the significant enhancement of the signal

Correlation of hepatic fractional extracellular space using gadolinium enhanced MRI with liver stiffness using magnetic resonance elastography.

PubMed

Wells, Michael L; Moynagh, Michael R; Carter, Rickey E; Childs, Robert A; Leitch, Cameron E; Fletcher, Joel G; Yeh, Benjamin M; Venkatesh, Sudhakar K

2017-01-01

To compare MR hepatic fractional extracellular space (fECS) to liver stiffness (LS) with magnetic resonance elastography (MRE) for evaluation of liver fibrosis. 71 consecutive patients with suspected chronic liver disease underwent standard liver MRI with MR elastography and additional delayed Gd-DTPA-enhanced sequences at 5 and 10 min in order to calculate hepatic fECS (%) and LS (kilopascals, kPa). Two radiologists blinded to clinical history examined MR images and calculated fECS and LS in identical locations for every patient. Interobserver agreement was calculated using the intraclass correlation coefficient. Pearson's correlation was calculated for LS and fECS measures, as was the area under the receiver operatic curve (AUROC), sensitivity and specificity of fECS to predict liver stiffness ≥2.93 and ≥5 kPa. The sensitivity of fECS for detecting fibrosis was separately analyzed in the subgroup of patients without anatomic findings of cirrhosis. Substantial to excellent interobserver agreement for both LS and fECS measurements was seen with intraclass correlation of 0.88 (95% CI 0.81-0.92) for LS, 0.77 (95% CI 0.66-0.85) for fECS 5 and 0.76 (95% CI 0.64-0.84) for fECS 10 . A significant correlation was found between MRE and fECS 5 (r = 0.47, p < 0.0001) and fECS 10 (r = 0.44, p < 0.0001). The performance of fECS improved for detection of advanced fibrosis (≥5 kPa) with AUROC, sensitivity and specificity of 0.72, 38%, and 94% for fECS 5 and 0.72, 67%, and 66% for fECS 10 . fECS correlates modestly with MRE-determined LS. fECS at MRI is a simple calculation to perform and may represent a practical way to suggest the presence of fibrosis during routine liver evaluation.

Effectiveness of late gadolinium enhancement to improve outcomes prediction in patients referred for cardiovascular magnetic resonance after echocardiography

PubMed Central

2013-01-01

Background Echocardiography (echo) is a first line test to assess cardiac structure and function. It is not known if cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) ordered during routine clinical practice in selected patients can add additional prognostic information after routine echo. We assessed whether CMR improves outcomes prediction after contemporaneous echo, which may have implications for efforts to optimize processes of care, assess effectiveness, and allocate limited health care resources. Methods and results We prospectively enrolled 1044 consecutive patients referred for CMR. There were 38 deaths and 3 cardiac transplants over a median follow-up of 1.0 years (IQR 0.4-1.5). We first reproduced previous survival curve strata (presence of LGE and ejection fraction (EF) < 50%) for transplant free survival, to support generalizability of any findings. Then, in a subset (n = 444) with contemporaneous echo (median 3 days apart, IQR 1–9), EF by echo (assessed visually) or CMR were modestly correlated (R2 = 0.66, p < 0.001), and 30 deaths and 3 transplants occurred over a median follow-up of 0.83 years (IQR 0.29-1.40). CMR EF predicted mortality better than echo EF in univariable Cox models (Integrated Discrimination Improvement (IDI) 0.018, 95% CI 0.008-0.034; Net Reclassification Improvement (NRI) 0.51, 95% CI 0.11-0.85). Finally, LGE further improved prediction beyond EF as determined by hazard ratios, NRI, and IDI in all Cox models predicting mortality or transplant free survival, adjusting for age, gender, wall motion, and EF. Conclusions Among those referred for CMR after echocardiography, CMR with LGE further improves risk stratification of individuals at risk for death or death/cardiac transplant. PMID:23324403

Radiation-induced Liver Injury after 3D-conformal Radiotherapy for Hepatocellular Carcinoma: Quantitative Assessment Using Gd-EOB-DTPA-enhanced MRI.

PubMed

Fukugawa, Yoshiyuki; Namimoto, Tomohiro; Toya, Ryo; Saito, Tetsuo; Yuki, Hideaki; Matsuyama, Tomohiko; Ikeda, Osamu; Yamashita, Yasuyuki; Oya, Natsuo

2017-02-01

Focal liver reaction (FLR) appears in the hepatobiliary-phase images of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (Gd-EOB-DTPA-enhanced MRI) following radiotherapy (RT). We investigated the threshold dose (TD) for FLR development in 13 patients with hepatocellular carcinoma (HCC) who underwent three-dimensional conformal radiotherapy (3D-CRT) with 45 Gy in 15 fractions. FLR volumes (FLRVs) were calculated based on planning CT images by referring to fused hepatobiliary- phase images. We also calculated the TD and the irradiated volumes (IVs) of the liver parenchyma at a given dose of every 5 Gy (IVdose) based on a dose-volume histogram (DVH). The median TD was 35.2 Gy. The median IV20, IV25, IV30, IV35, IV40, and IV45 values were 371.1, 274.8, 233.4, 188.6, 145.8, and 31.0 ml, respectively. The median FLRV was 144.9 ml. There was a significant difference between the FLRV and IV20, IV25, and IV45 (p<0.05), but no significant differences between the FLRV and IV30, IV35, or IV40. These results suggest that the threshold dose of the FLR is approx. 35 Gy in HCC patients who undergo 3D-CRT in 15 fractions. The percentage of the whole liver volume receiving a dose of more than 30-40 Gy (V30-40) is a potential candidate optimal DVH parameter for this fractionation schedule.

A novel contrast agent with rare earth-doped up-conversion luminescence and Gd-DTPA magnetic resonance properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu Qing; Wei Daixu; Cheng Jiejun

2012-08-15

The magnetic-luminescent multifunctional nanoparticles based on Gd-DTPA and NaYF{sub 4}:Yb, Er were successfully synthesized by the conjugation of activated DTPA and silica-coated/surface-aminolated NaYF{sub 4}:Yb, Er nanoparticles through EDC/NHS coupling chemistry. The as-prepared products were characterized by powder X-ray diffraction, transmission electron microscopy, dynamic light scattering, energy dispersive X-ray analysis, and fourier transform infrared spectrometry. The room-temperature upconversion luminescent spectra and T{sub 1}-weighted maps of the obtained nanoparticles were carried out by 980 nm NIR light excitation and a 3T MR imaging scanner, respectively. The results indicated that the as-synthesized multifunctional nanoparticles with small size, highly solubility in water, and bothmore » high MR relaxivities and upconversion luminescence may have potential usage for MR imaging in future. - Graphical abstract: We have synthesized magnetic-luminescent multifunctional nanoparticles based on Gd-DTPA and NaYF4:Yb, Er by the conjugation of activated DTPA and silica-coated/surface-aminolated NaYF4:Yb, Er nanoparticles through EDC/NHS coupling chemistry. Highlights: Black-Right-Pointing-Pointer A novel magnetic-luminescent multifunctional nanoparticles are synthesized. Black-Right-Pointing-Pointer The nanoparticles are highly efficient for luminescence and T{sub 1}-weighted MR imaging. Black-Right-Pointing-Pointer The nanoparticles are small in size and highly solubility in water. Black-Right-Pointing-Pointer The nanoparticles hold great potential usage for future biomedical engineering.« less

Cardiovascular Magnetic Resonance and prognosis in cardiac amyloidosis

PubMed Central

Maceira, Alicia M; Prasad, Sanjay K; Hawkins, Philip N; Roughton, Michael; Pennell, Dudley J

2008-01-01

Background Cardiac involvement is common in amyloidosis and associated with a variably adverse outcome. We have previously shown that cardiovascular magnetic resonance (CMR) can assess deposition of amyloid protein in the myocardial interstitium. In this study we assessed the prognostic value of late gadolinium enhancement (LGE) and gadolinium kinetics in cardiac amyloidosis in a prospective longitudinal study. Materials and methods The pre-defined study end point was all-cause mortality. We prospectively followed a cohort of 29 patients with proven cardiac amyloidosis. All patients underwent biopsy, 2D-echocardiography and Doppler studies, 123I-SAP scintigraphy, serum NT pro BNP assay, and CMR with a T1 mapping method and late gadolinium enhancement (LGE). Results Patients with were followed for a median of 623 days (IQ range 221, 1436), during which 17 (58%) patients died. The presence of myocardial LGE by itself was not a significant predictor of mortality. However, death was predicted by gadolinium kinetics, with the 2 minute post-gadolinium intramyocardial T1 difference between subepicardium and subendocardium predicting mortality with 85% accuracy at a threshold value of 23 ms (the lower the difference the worse the prognosis). Intramyocardial T1 gradient was a better predictor of survival than FLC response to chemotherapy (Kaplan Meier analysis P = 0.049) or diastolic function (Kaplan-Meier analysis P = 0.205). Conclusion In cardiac amyloidosis, CMR provides unique information relating to risk of mortality based on gadolinium kinetics which reflects the severity of the cardiac amyloid burden. PMID:19032744

In vivo transport of Gd-DTPA2- into human meniscus and cartilage assessed with delayed gadolinium-enhanced MRI of cartilage (dGEMRIC)

PubMed Central

2014-01-01

Background Impaired stability is a risk factor in knee osteoarthritis (OA), where the whole joint and not only the joint cartilage is affected. The meniscus provides joint stability and is involved in the early pathological progress of OA. Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) has been used to identify pre-radiographic changes in the cartilage in OA, but has been used less commonly to examine the meniscus, and then using only a double dose of the contrast agent. The purpose of this study was to enable improved early OA diagnosis by investigate the temporal contrast agent distribution in the meniscus and femoral cartilage simultaneously, in healthy volunteers, using 3D dGEMRIC at two different doses of the contrast agent Gd-DTPA2-. Methods The right knee in 12 asymptomatic volunteers was examined using a 3D Look-Locker sequence on two occasions after an intravenous injection of a double or triple dose of Gd-DTPA2- (0.2 or 0.3 mmol/kg body weight). The relaxation time (T1) and relaxation rate (R1 = 1/T1) were measured in the meniscus and femoral cartilage before, and 60, 90, 120 and 180 minutes after injection, and the change in relaxation rate (ΔR1) was calculated. Paired t-test and Analysis of Variance (ANOVA) were used for statistical evaluation. Results The triple dose yielded higher concentrations of Gd-DTPA2- in the meniscus and cartilage than the double dose, but provided no additional information. The observed patterns of ΔR1 were similar for double and triple doses of the contrast agent. ΔR1 was higher in the meniscus than in femoral cartilage in the corresponding compartments at all time points after injection. ΔR1 increased until 90-180 minutes in both the cartilage and the meniscus (p < 0.05), and was lower in the medial than in the lateral meniscus at all time points (p < 0.05). A faster increase in ΔR1 was observed in the vascularized peripheral region of the posterior medial meniscus, than in the avascular central

Magnetic resonance and confocal imaging of solute penetration into the lens reveals a zone of restricted extracellular space diffusion.

PubMed

Vaghefi, Ehsan; Walker, Kerry; Pontre, Beau P; Jacobs, Marc D; Donaldson, Paul J

2012-06-01

It has been proposed that in the absence of blood supply, the ocular lens operates an internal microcirculation system that delivers nutrients to internalized fiber cells faster and more efficiently than would occur by passive diffusion alone. To visualize the extracellular space solute fluxes potentially generated by this system, bovine lenses were organ cultured in artificial aqueous humor (AAH) for 4 h in the presence or absence of two gadolinium-based contrast agents, ionic Gd(3+), or a chelated form of Gd(3+), Gd-diethylenetriamine penta-acetic acid (Gd-DTPA; mol mass = 590 Da). Contrast reagent penetration into the lens core was monitored in real time using inversion recovery-spin echo (IR-SE) magnetic resonance imaging (MRI), while steady-state accumulation of [Gd-DTPA](-2) was also determined by calculating T1 values. After incubation, lenses were fixed and cryosectioned, and sections were labeled with the membrane marker wheat germ agglutinin (WGA). Sections were imaged by confocal microscopy using standard and reflectance imaging modalities to visualize the fluorescent WGA label and gadolinium reagents, respectively. Real-time IR-SE MRI showed rapid penetration of Gd(3+) into the outer cortex of the lens and a subsequent bloom of signal in the core. These two areas of signal were separated by an area in the inner cortex that limited entry of Gd(3+). Similar results were obtained for Gd-DTPA, but the penetration of the larger negatively charged molecule into the core could only be detected by calculating T1 values. The presence of Gd-DTPA in the extracellular space of the outer cortex and core, but its apparent absence from the inner cortex was confirmed using reflectance imaging of equatorial sections. In axial sections, Gd-DTPA was associated with the sutures, suggesting these structures provide a pathway from the surface, across the inner cortex barrier to the lens core. Our studies have revealed inner and outer boundaries of a zone within which a

Applying Amide Proton Transfer MR Imaging to Hybrid Brain PET/MR: Concordance with Gadolinium Enhancement and Added Value to [18F]FDG PET.

PubMed

Sun, Hongzan; Xin, Jun; Zhou, Jinyuan; Lu, Zaiming; Guo, Qiyong

2018-06-01

The purpose of this study is to evaluate the diagnostic concordance and metric correlations of amide proton transfer (APT) imaging with gadolinium-enhanced magnetic resonance imaging (MRI) and 2-deoxy-2-[ 18 F-]fluoro-D-glucose ([ 18 F]FDG) positron emission tomography (PET), using hybrid brain PET/MRI. Twenty-one subjects underwent brain gadolinium-enhanced [ 18 F]FDG PET/MRI prospectively. Imaging accuracy was compared between unenhanced MRI, MRI with enhancement, APT-weighted (APTW) images, and PET based on six diagnostic criteria. Among tumors, the McNemar test was further used for concordance assessment between gadolinium-enhanced imaging, APT imaging, and [ 18 F]FDG PET. As well, the relation of metrics between APT imaging and PET was analyzed by the Pearson correlation analysis. APT imaging and gadolinium-enhanced MRI showed superior and similar diagnostic accuracy. APTW signal intensity and gadolinium enhancement were concordant in 19 tumors (100 %), while high [ 18 F]FDG avidity was shown in only 12 (63.2 %). For the metrics from APT imaging and PET, there was significant correlation for 13 hypermetabolic tumors (P < 0.05) and no correlation for the remaining six [ 18 F]FDG-avid tumors. APT imaging can be used to increase diagnostic accuracy with no need to administer gadolinium chelates. APT imaging may provide an added value to [ 18 F]FDG PET in the evaluation of tumor metabolic activity during brain PET/MR studies.

Caspase-responsive smart gadolinium-based contrast agent for magnetic resonance imaging of drug-induced apoptosis.

PubMed

Ye, Deju; Shuhendler, Adam J; Pandit, Prachi; Brewer, Kimberly D; Tee, Sui Seng; Cui, Lina; Tikhomirov, Grigory; Rutt, Brian; Rao, Jianghong

2014-10-01

Non-invasive detection of caspase-3/7 activity in vivo has provided invaluable predictive information regarding tumor therapeutic efficacy and anti-tumor drug selection. Although a number of caspase-3/7 targeted fluorescence and positron emission tomography (PET) imaging probes have been developed, there is still a lack of gadolinium (Gd)-based magnetic resonance imaging (MRI) probes that enable high spatial resolution detection of caspase-3/7 activity in vivo . Here we employ a self-assembly approach and develop a caspase-3/7 activatable Gd-based MRI probe for monitoring tumor apoptosis in mice. Upon reduction and caspase-3/7 activation, the caspase-sensitive nano-aggregation MR probe (C-SNAM: 1 ) undergoes biocompatible intramolecular cyclization and subsequent self-assembly into Gd-nanoparticles (GdNPs). This results in enhanced r 1 relaxivity-19.0 (post-activation) vs. 10.2 mM -1 s -1 (pre-activation) at 1 T in solution-and prolonged accumulation in chemotherapy-induced apoptotic cells and tumors that express active caspase-3/7. We demonstrate that C-SNAM reports caspase-3/7 activity by generating a significantly brighter T 1 -weighted MR signal compared to non-treated tumors following intravenous administration of C-SNAM, providing great potential for high-resolution imaging of tumor apoptosis in vivo .

Right ventricular stress-induced perfusion defects and late gadolinium enhancement in coronary artery disease.

PubMed

Milks, Michael Wesley; Upadhya, Bharathi; Hall, Michael E; Vasu, Sujethra; Hundley, William Gregory; Stacey, Richard Brandon

2015-01-01

The assessment of right ventricular (RV) perfusion defects has remained challenging during vasodilator stress perfusion with cardiovascular magnetic resonance (CMR). The significance of RV signal abnormalities during vasodilator stress perfusion and late gadolinium-enhanced CMR is yet uncertain. Among 61 individuals who underwent adenosine CMR stress testing before cardiac catheterization, we assessed the severity of coronary artery stenoses, mortality, the presence of stress and rest perfusion defects, as well as the presence of late gadolinium enhancement (LGE). Right ventricular stress-induced perfusion defects were positively associated with left anterior descending artery and proximal right coronary artery stenoses but were negatively associated with left circumflex artery stenoses. The presence of RVLGE was associated with mortality, but 77% of those with RVLGE also had left ventricular LGE. Proximal right coronary artery and left anterior descending artery stenoses are positively associated, whereas left circumflex artery stenoses are negatively associated with RV stress-induced perfusion defects. Right ventricular LGE was associated with mortality, but further study is needed to determine whether this is independent of left ventricular LGE.

Application of Paramagnetically Tagged Molecules for Magnetic Resonance Imaging of Biofilm Mass Transport Processes▿

PubMed Central

Ramanan, B.; Holmes, W. M.; Sloan, W. T.; Phoenix, V. R.

2010-01-01

Molecules become readily visible by magnetic resonance imaging (MRI) when labeled with a paramagnetic tag. Consequently, MRI can be used to image their transport through porous media. In this study, we demonstrated that this method could be applied to image mass transport processes in biofilms. The transport of a complex of gadolinium and diethylenetriamine pentaacetic acid (Gd-DTPA), a commercially available paramagnetic molecule, was imaged both in agar (as a homogeneous test system) and in a phototrophic biofilm. The images collected were T1 weighted, where T1 is an MRI property of the biofilm and is dependent on Gd-DTPA concentration. A calibration protocol was applied to convert T1 parameter maps into concentration maps, thus revealing the spatially resolved concentrations of this tracer at different time intervals. Comparing the data obtained from the agar experiment with data from a one-dimensional diffusion model revealed that transport of Gd-DTPA in agar was purely via diffusion, with a diffusion coefficient of 7.2 × 10−10 m2 s−1. In contrast, comparison of data from the phototrophic biofilm experiment with data from a two-dimensional diffusion model revealed that transport of Gd-DTPA inside the biofilm was by both diffusion and advection, equivalent to a diffusion coefficient of 1.04 × 10−9 m2 s−1. This technology can be used to further explore mass transport processes in biofilms, either by using the wide range of commercially available paramagnetically tagged molecules and nanoparticles or by using bespoke tagged molecules. PMID:20435773

Resonant Raman scattering from silicon nanoparticles enhanced by magnetic response.

PubMed

Dmitriev, Pavel A; Baranov, Denis G; Milichko, Valentin A; Makarov, Sergey V; Mukhin, Ivan S; Samusev, Anton K; Krasnok, Alexander E; Belov, Pavel A; Kivshar, Yuri S

2016-05-05

Enhancement of optical response with high-index dielectric nanoparticles is attributed to the excitation of their Mie-type magnetic and electric resonances. Here we study Raman scattering from crystalline silicon nanoparticles and reveal that magnetic dipole modes have a much stronger effect on the scattering than electric modes of the same order. We demonstrate experimentally a 140-fold enhancement of the Raman signal from individual silicon spherical nanoparticles at the magnetic dipole resonance. Our results confirm the importance of the optically-induced magnetic response of subwavelength dielectric nanoparticles for enhancing light-matter interactions.

The evolution of gadolinium based contrast agents: from single-modality to multi-modality

NASA Astrophysics Data System (ADS)

Zhang, Li; Liu, Ruiqing; Peng, Hui; Li, Penghui; Xu, Zushun; Whittaker, Andrew K.

2016-05-01

Gadolinium-based contrast agents are extensively used as magnetic resonance imaging (MRI) contrast agents due to their outstanding signal enhancement and ease of chemical modification. However, it is increasingly recognized that information obtained from single modal molecular imaging cannot satisfy the higher requirements on the efficiency and accuracy for clinical diagnosis and medical research, due to its limitation and default rooted in single molecular imaging technique itself. To compensate for the deficiencies of single function magnetic resonance imaging contrast agents, the combination of multi-modality imaging has turned to be the research hotpot in recent years. This review presents an overview on the recent developments of the functionalization of gadolinium-based contrast agents, and their application in biomedicine applications.

Evaluation of the vascular anatomy in potential living kidney donors with gadolinium-enhanced magnetic resonance angiography: comparison with digital subtraction angiography and intraoperative findings.

PubMed

Asgari, Majid A; Dadkhah, Farid; Ghadian, Ali R; Razzaghi, Mohammad R; Noorbala, Mohammad H; Amini, Erfan

2011-01-01

X-ray contrast arteriography has traditionally been used for pre-operative evaluation in living kidney donors. However, magnetic resonance angiography (MRA) offers a non-invasive alternative, which has been considered to be less accurate. This study was performed to determine whether MRA in the pre-operative investigation of living kidney donors provides sufficient information. From December 2005 to December 2007, 173 potential live donors were evaluated in this study. Donors performed digital subtraction angiography (DSA) and those with one or more accessory arteries at least on one side recruited for further evaluation with three-dimensional gadolinium-enhanced MRA. A total of 30 donors constituted the study population. When compared with DSA as the reference method, MRA detected 20 of 36 renal accessory arteries which indicates a sensitivity of 55.6%. The difference between MRA and DSA in identifying accessory renal arteries was significant (p-value <0.001). Considering intraoperative findings as the standard of reference, MRA depicted correctly four of six (66.7%) accessory arteries on the transplanted kidneys. MRA has the advantage of avoiding exposure to ionizing radiation and is non-invasive. These are important considerations in pre-operative evaluation of a generally healthy donor population. However, MRA provides suboptimal accuracy in detecting small accessory arteries. © 2010 John Wiley & Sons A/S.

Gd-DTPA L-cystine bisamide copolymers as novel biodegradable macromolecular contrast agents for MR blood pool imaging.

PubMed

Kaneshiro, Todd L; Ke, Tianyi; Jeong, Eun-Kee; Parker, Dennis L; Lu, Zheng-Rong

2006-06-01

The purpose of this study was to synthesize biodegradable Gd-DTPA L-cystine bisamide copolymers (GCAC) as safe and effective, macromolecular contrast agents for magnetic resonance imaging (MRI) and to evaluate their biodegradability and efficacy in MR blood pool imaging in an animal model. Three new biodegradable GCAC with different substituents at the cystine bisamide [R = H (GCAC), CH2CH2CH3 (Gd-DTPA L-cystine bispropyl amide copolymers, GCPC), and CH(CH3)2 (Gd-DTPA cystine bisisopropyl copolymers, GCIC)] were prepared by the condensation copolymerization of diethylenetriamine pentaacetic acid (DTPA) dianhydride with cystine bisamide or bisalkyl amides, followed by complexation with gadolinium triacetate. The degradability of the agents was studied in vitro by incubation in 15 microM cysteine and in vivo with Sprague-Dawley rats. The kinetics of in vivo contrast enhancement was investigated in Sprague-Dawley rats on a Siemens Trio 3 T scanner. The apparent molecular weight of the polydisulfide Gd(III) chelates ranged from 22 to 25 kDa. The longitudinal (T1) relaxivities of GCAC, GCPC, and GCIC were 4.37, 5.28, and 5.56 mM(-1) s(-1) at 3 T, respectively. The polymeric ligands and polymeric Gd(III) chelates readily degraded into smaller molecules in incubation with 15 microM cysteine via disulfide-thiol exchange reactions. The in vitro degradation rates of both the polymeric ligands and macromolecular Gd(III) chelates decreased as the steric effect around the disulfide bonds increased. The agents readily degraded in vivo, and the catabolic degradation products were detected in rat urine samples collected after intravenous injection. The agents showed strong contrast enhancement in the blood pool, major organs, and tissues at a dose of 0.1 mmol Gd/kg. The difference of their in vitro degradability did not significantly alter the kinetics of in vivo contrast enhancement of the agents. These novel GCAC are promising contrast agents for cardiovascular and tumor MRI

Hepatic function imaging using dynamic Gd-EOB-DTPA enhanced MRI and pharmacokinetic modeling.

PubMed

Ning, Jia; Yang, Zhiying; Xie, Sheng; Sun, Yongliang; Yuan, Chun; Chen, Huijun

2017-10-01

To determine whether pharmacokinetic modeling parameters with different output assumptions of dynamic contrast-enhanced MRI (DCE-MRI) using Gd-EOB-DTPA correlate with serum-based liver function tests, and compare the goodness of fit of the different output assumptions. A 6-min DCE-MRI protocol was performed in 38 patients. Four dual-input two-compartment models with different output assumptions and a published one-compartment model were used to calculate hepatic function parameters. The Akaike information criterion fitting error was used to evaluate the goodness of fit. Imaging-based hepatic function parameters were compared with blood chemistry using correlation with multiple comparison correction. The dual-input two-compartment model assuming venous flow equals arterial flow plus portal venous flow and no bile duct output better described the liver tissue enhancement with low fitting error and high correlation with blood chemistry. The relative uptake rate Kir derived from this model was found to be significantly correlated with direct bilirubin (r = -0.52, P = 0.015), prealbumin concentration (r = 0.58, P = 0.015), and prothrombin time (r = -0.51, P = 0.026). It is feasible to evaluate hepatic function by proper output assumptions. The relative uptake rate has the potential to serve as a biomarker of function. Magn Reson Med 78:1488-1495, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

[Role of cardiac magnetic resonance in cardiac involvement of Fabry disease].

PubMed

Serra, Viviana M; Barba, Miguel Angel; Torrá, Roser; Pérez De Isla, Leopoldo; López, Mónica; Calli, Andrea; Feltes, Gisela; Torras, Joan; Valverde, Victor; Zamorano, José L

2010-09-04

Fabry disease is a hereditary disorder. Clinical manifestations are multisystemic. The majority of the patients remain undiagnosed until late in life, when alterations could be irreversible. Early detection of cardiac symptoms is of major interest in Fabry's disease (FD) in order to gain access to enzyme replacement therapy. Echo-Doppler tissular imaging (TDI) has been used as a cardiologic early marker in FD. This study is intended to determine whether the cardiac magnetic resonance is as useful tool as TDI for the early detection of cardiac affectation in FD. Echocardiography, tissue Doppler and Cardio magnetic resonance was performed in 20 patients with confirmed Fabry Disease. Left ventricular hypertrophy was defined as septum and left ventricular posterior wall thickness ≥12 mm. An abnormal TDI velocity was defined as (Sa), (Ea) and/or (Aa) velocities <8 cm/s at either the septal or lateral corner. Late phase gadolinium-enhanced images sequences were obtained using magnetic resonance. Twenty patients included in the study were divided into three groups: 1. Those without left ventricular hypertrophy nor tissue Doppler impairment 2. Those without left ventricular hypertrophy and tissue Doppler impairment 3. Those with left ventricular hypertrophy and Tissue Doppler impairment. Late gadolinium enhancement was found in only one patient, who has already altered DTI and LVH. Tissue Doppler imaging (TDI) is the only diagnostic tool able to provide early detection of cardiac affectation in patients with FD. Magnetic resonance provides information of the disease severity in patients with LVH, but can not be used as an early marker of cardiac disease in patients with FD. However MRI could be of great value for diagnostic stratification. Copyright © 2009 Elsevier España, S.L. All rights reserved.

Multifunctional gadolinium-based dendritic macromolecules as liver targeting imaging probes.

PubMed

Luo, Kui; Liu, Gang; He, Bin; Wu, Yao; Gong, Qingyong; Song, Bin; Ai, Hua; Gu, Zhongwei

2011-04-01

The quest for highly efficient and safe contrast agents has become the key factor for successful application of magnetic resonance imaging (MRI). The gadolinium (Gd) based dendritic macromolecules, with precise and tunable nanoscopic sizes, are excellent candidates as multivalent MRI probes. In this paper, a novel series of Gd-based multifunctional peptide dendritic probes (generation 2, 3, and 4) possessing highly controlled structures and single molecular weight were designed and prepared as liver MRI probes. These macromolecular Gd-ligand agents exhibited up to 3-fold increase in T(1) relaxivity comparing to Gd-DTPA complexes. No obvious in vitro cytotoxicity was observed from the measured concentrations. These dendritic probes were further functionalized with multiple galactosyl moieties and led to much higher cell uptake in vitro as demonstrated in T(1)-weighted scans. During in vivo animal studies, the probes provided better signal intensity (SI) enhancement in mouse liver, especially at 60 min post-injection, with the most efficient enhancement from the galactosyl moiety decorated third generation dendrimer. The imaging results were verified with analysis of Gd content in liver tissues. The design strategy of multifunctional Gd-ligand peptide dendritic macromolecules in this study may be used for developing other sensitive MRI probes with targeting capability. Copyright © 2011 Elsevier Ltd. All rights reserved.

Usefulness of combining gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging and contrast-enhanced ultrasound for diagnosing the macroscopic classification of small hepatocellular carcinoma.

PubMed

Kobayashi, Tomoki; Aikata, Hiroshi; Hatooka, Masahiro; Morio, Kei; Morio, Reona; Kan, Hiromi; Fujino, Hatsue; Fukuhara, Takayuki; Masaki, Keiichi; Ohno, Atsushi; Naeshiro, Noriaki; Nakahara, Takashi; Honda, Yohji; Murakami, Eisuke; Kawaoka, Tomokazu; Tsuge, Masataka; Hiramatsu, Akira; Imamura, Michio; Kawakami, Yoshiiku; Hyogo, Hideyuki; Takahashi, Shoichi; Chayama, Kazuaki

2015-11-01

Non-simple nodules in hepatocellular carcinoma (HCC) correlate with poor prognosis. Therefore, we examined the diagnostic ability of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (EOB-MRI) and contrast-enhanced ultrasound (CEUS) for diagnosing the macroscopic classification of small HCCs. A total of 85 surgically resected nodules (≤30 mm) were analyzed. HCCs were pathologically classified as simple nodular (SN) and non-SN. By evaluating hepatobiliary phase (HBP) of EOB-MRI and Kupffer phase of CEUS, the diagnostic abilities of both modalities to correctly distinguish between SN and non-SN were compared. Forty-six nodules were diagnosed as SN and the remaining 39 nodules as non-SN. The area under the ROC curve (AUROCs, 95% confidence interval) for the diagnosis of non-SN were EOB-MRI, 0.786 (0.682-0.890): CEUS, 0.784 (0.679-0.889), in combination, 0.876 (0.792-0.959). The sensitivity, specificity, and accuracy were 64.1%, 95.7%, and 81.2% in EOB-MRI, 56.4%, 97.8%, and 78.8% in CEUS, and 84.6%, 95.7%, and 90.6% in combination, respectively. High diagnostic ability was obtained when diagnosed in both modalities combined. The sensitivity was especially statistically significant compared to CEUS. Combined diagnosis by EOB-MRI and CEUS can provide high-quality imaging assessment for determining non-SN in small HCCs. • Non-SN has a higher frequency of MVI and intrahepatic metastasis than SN. • Macroscopic classification is useful to choose the treatment strategy for small HCCs. • Diagnostic ability for macroscopic findings of EOB-MRI and CEUS were statistically equal. • The diagnosis of macroscopic findings by individual modality has limitations. • Combined diagnosis of EOB-MRI and CEUS provides high diagnostic ability.

Tissue gadolinium deposition in hepatorenally impaired rats exposed to Gd-EOB-DTPA: evaluation with inductively coupled plasma mass spectrometry (ICP-MS).

PubMed

Sato, Tomohiro; Tamada, Tsutomu; Watanabe, Shigeru; Nishimura, Hirotake; Kanki, Akihiko; Noda, Yasufumi; Higaki, Atsushi; Yamamoto, Akira; Ito, Katsuyoshi

2015-06-01

This study was undertaken to quantify tissue gadolinium (Gd) deposition in hepatorenally impaired rats exposed to gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) by means of inductively coupled plasma mass spectrometry (ICP-MS) and to compare differences in Gd distribution among major organs as possible triggers for nephrogenic systemic fibrosis. Five hepatorenally impaired rats (5/6-nephrectomized, with carbon-tetrachloride-induced liver fibrosis) were injected with Gd-EOB-DTPA. Histological assessment was conducted and Gd content of the skin, liver, kidneys, lungs, heart, spleen, diaphragm, and femoral muscle was measured by inductively coupled plasma mass spectrometry (ICP-MS) at 7 days after last injection. In addition, five renally impaired rats were injected with Gd-EOB-DTPA and the degree of tissue Gd deposition was compared with that in the hepatorenally impaired rats. ICP-MS analysis revealed significantly higher Gd deposition in the kidneys, spleen, and liver (p = 0.009-0.047) in the hepatorenally impaired group (42.6 ± 20.1, 17.2 ± 6.1, 8.4 ± 3.2 μg/g, respectively) than in the renally impaired group (17.2 ± 7.7, 5.4 ± 2.1, 2.8 ± 0.7 μg/g, respectively); no significant difference was found for other organs. In the hepatorenally impaired group, Gd was predominantly deposited in the kidneys, followed by the spleen, liver, lungs, skin, heart, diaphragm, and femoral muscle. Histopathological investigation revealed hepatic fibrosis in the hepatorenally impaired group. Compared with renally impaired rats, tissue Gd deposition in hepatorenally impaired rats exposed to Gd-EOB-DTPA was significantly increased in the kidneys, spleen, and liver, probably due to the impairment of the dual excretion pathways of the urinary and biliary systems.

T1 mapping using saturation recovery single-shot acquisition at 3-tesla magnetic resonance imaging in hypertrophic cardiomyopathy: comparison to late gadolinium enhancement.

PubMed

Ogawa, Ryo; Kido, Tomoyuki; Nakamura, Masashi; Kido, Teruhito; Kurata, Akira; Uetani, Teruyoshi; Ogimoto, Akiyoshi; Miyagawa, Masao; Mochizuki, Teruhito

2017-03-01

We evaluated the T1 values of segments and slices and the reproducibility in healthy controls, using saturation recovery single-shot acquisition (SASHA) at 3T magnetic resonance imaging. Moreover, we examined the difference in T1 values between hypertrophic cardiomyopathy (HCM) and healthy controls, and compared those with late gadolinium enhancement (LGE). Twenty-one HCM patients and 10 healthy controls underwent T1 mapping before and after contrast administration. T1 values were measured in 12 segments. Native T1 values were significantly longer in HCM than in healthy controls [1373 ms (1312-1452 ms) vs. 1279 ms (1229-1326 ms); p < 0.0001]. Even in HCM segments without LGE, native T1 values were significantly longer than in healthy control segments [1366 ms (1300-1439 ms) vs. 1279 ms (1229-1326 ms); p < 0.0001]. Using a cutoff value of 1327 ms for septal native T1 values, we differentiated between HCM and healthy controls with 95% sensitivity, 90% specificity, 94% accuracy, and an area under the curve of 0.95. Native T1 values using a SASHA at 3T could differentiate HCM from healthy controls. Moreover, native T1 values have the potential to detect abnormal myocardium that cannot be identified adequately by LGE in HCM.

Gd-EOB-DTPA-enhanced MRI for monitoring future liver remnant function after portal vein embolization and extended hemihepatectomy: A prospective trial.

PubMed

Geisel, Dominik; Raabe, Philip; Lüdemann, Lutz; Malinowski, Maciej; Stockmann, Martin; Seehofer, Daniel; Pratschke, Johann; Hamm, Bernd; Denecke, Timm

2017-07-01

To evaluate changes in liver function after right portal vein embolization (PVE) and extended right hemihepatectomy using gadolinium ethoxybenzyl-DTPA-enhanced (Gd-EOB-DTPA) MRI. In this prospective trial, 37 patients undergoing PVE were examined before and 14 and 28 days after PVE and 10 days after extended hemihepatectomy using Gd-EOB-DTPA-enhanced MRI. Lobar volume, kinetic growth rate (KGR), relative enhancement (RE) as well as hepatocellular uptake index (HUI) and fat signal fraction (FSF) were calculated for each lobe. RE of the left liver lobe (LLL) was steadily increasing after PVE and decreased to 0.48 ± 0.19 10 days after surgery, which is significantly lower than 14 days and 28 days post PVE (P < 0.05). KGR was 14.06 ± 9.82%/week for the period from PVE to 14 days after PVE. HUI of the LLL increased steadily after PVE and was significantly higher at both 14 and 28 days after PVE compared to pre PVE (P < 0.05). HUI of the residual liver after surgery was lower than before. Gd-EOB-DTPA-enhanced MRI may be used to monitor the functional increase in the FLR after PVE and to depict the intraoperative liver injury leading to a decrease in liver remnant function. • The most significant FLR volume increase happens within the first 14 days. • No MRI parameter was able to predict the success of FLR growth. • Our data suggest an early resection about 14 days after PVE. • Routine Gd-EOB-DTPA-enhanced MRI might be suitable to replace ICG-test.

Gadolinium-encapsulating iron oxide nanoprobe as activatable NMR/MRI contrast agent.

PubMed

Santra, Santimukul; Jativa, Samuel D; Kaittanis, Charalambos; Normand, Guillaume; Grimm, Jan; Perez, J Manuel

2012-08-28

Herein we report a novel gadolinium-encapsulating iron oxide nanoparticle-based activatable NMR/MRI nanoprobe. In our design, Gd-DTPA is encapsulated within the poly(acrylic acid) (PAA) polymer coating of a superparamagnetic iron oxide nanoparticle (IO-PAA), yielding a composite magnetic nanoprobe (IO-PAA-Gd-DTPA) with quenched longitudinal spin-lattice magnetic relaxation (T(1)). Upon release of the Gd-DTPA complex from the nanoprobe's polymeric coating in acidic media, an increase in the T(1) relaxation rate (1/T(1)) of the composite magnetic nanoprobe was observed, indicating a dequenching of the nanoprobe with a corresponding increase in the T(1)-weighted MRI signal. When a folate-conjugated nanoprobe was incubated in HeLa cells, a cancer cell line overexpressing folate receptors, an increase in the 1/T(1) signal was observed. This result suggests that, upon receptor-mediated internalization, the composite magnetic nanoprobe degraded within the cell's lysosome acidic (pH 5.0) environment, resulting in an intracellular release of Gd-DTPA complex with subsequent T(1) activation. In addition, when an anticancer drug (Taxol) was coencapsulated with the Gd-DTPA within the folate receptor targeting composite magnetic nanoprobe, the T(1) activation of the probe coincided with the rate of drug release and corresponding cytotoxic effect in cell culture studies. Taken together, these results suggest that our activatable T(1) nanoagent could be of great importance for the detection of acidic tumors and assessment of drug targeting and release by MRI.

Magnetic resonance angiography: current status and future directions

PubMed Central

2011-01-01

With recent improvement in hardware and software techniques, magnetic resonance angiography (MRA) has undergone significant changes in technique and approach. The advent of 3.0 T magnets has allowed reduction in exogenous contrast dose without compromising overall image quality. The use of novel intravascular contrast agents substantially increases the image windows and decreases contrast dose. Additionally, the lower risk and cost in non-contrast enhanced (NCE) MRA has sparked renewed interest in these methods. This article discusses the current state of both contrast-enhanced (CE) and NCE-MRA. New CE-MRA methods take advantage of dose reduction at 3.0 T, novel contrast agents, and parallel imaging methods. The risks of gadolinium-based contrast media, and the NCE-MRA methods of time-of-flight, steady-state free precession, and phase contrast are discussed. PMID:21388544

Can the biliary enhancement of Gd-EOB-DTPA predict the degree of liver function?

PubMed

Okada, Masahiro; Ishii, Kazunari; Numata, Kazushi; Hyodo, Tomoko; Kumano, Seishi; Kitano, Masayuki; Kudo, Masatoshi; Murakami, Takamichi

2012-06-01

Excretion of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) in the bile may be related to liver function, because of elimination from the liver after preferential uptake by hepatocytes. The purpose of this study was to investigate the relation between liver and biliary enhancement in patients with or without liver dysfunction, and to compare the tumor-to-liver contrast in these patients. Forty patients [group 1: normal liver and Child-Pugh class A in 20 patients, group 2: Child-Pugh class B in 18 patients and Child-Pugh C in 2] were evaluated. All patients underwent MR imaging of the liver using a 1.5-Tesla system. T1-weighted 3D images were obtained at 5, 10, 15 and 20 minutes after Gd-EOB-DTPA injection. The relation between group 3 (total bilirubin <1.8 mg/dL) and group 4 (total bilirubin ≥1.8 mg/dL) was investigated at 20 minutes. Liver and biliary signals were measured, and compared between groups 1 and 2 or groups 3 and 4. Tumor-to-liver ratio was also evaluated between groups 1 and 2. Scheffe's post-hoc test after two-way repeated-measures ANOVA and Pearson's correlation test were used for statistical analysis. Liver enhancement showed significant difference at all time points between groups 1 and 2. Biliary enhancement did not show a significant difference between groups 1 and 2 at 5 minutes, but did at 10, 15 and 20 minutes. At 20 minutes, significant differences between groups 3 and 4 were seen for liver and biliary enhancement. At all time points, liver enhancement correlated with biliary enhancement in both groups. At 5 minutes and 20 minutes, statistical differences between groups 1 and 2 were seen for tumor-to-liver ratio. The degree of biliary enhancement has a close correlation to that of liver enhancement. It is especially important that insufficient liver enhancement causes lower tumor-to-liver contrast in the hepatobiliary phase of Gd-EOB-DTPA.

A Feasibility Study to Determine Whether Clinical Contrast Enhanced Magnetic Resonance Imaging can Detect Increased Bladder Permeability in Patients with Interstitial Cystitis.

PubMed

Towner, Rheal A; Wisniewski, Amy B; Wu, Dee H; Van Gordon, Samuel B; Smith, Nataliya; North, Justin C; McElhaney, Rayburt; Aston, Christopher E; Shobeiri, S Abbas; Kropp, Bradley P; Greenwood-Van Meerveld, Beverley; Hurst, Robert E

2016-03-01

Interstitial cystitis/bladder pain syndrome is a bladder pain disorder associated with voiding symptomatology and other systemic chronic pain disorders. Currently diagnosing interstitial cystitis/bladder pain syndrome is complicated as patients present with a wide range of symptoms, physical examination findings and clinical test responses. One hypothesis is that interstitial cystitis symptoms arise from increased bladder permeability to urine solutes. This study establishes the feasibility of using contrast enhanced magnetic resonance imaging to quantify bladder permeability in patients with interstitial cystitis. Permeability alterations in bladder urothelium were assessed by intravesical administration of the magnetic resonance imaging contrast agent Gd-DTPA (Gd-diethylenetriaminepentaacetic acid) in a small cohort of patients. Magnetic resonance imaging signal intensity in patient and control bladders was compared regionally and for entire bladders. Quantitative assessment of magnetic resonance imaging signal intensity indicated a significant increase in signal intensity in anterior bladder regions compared to posterior regions in patients with interstitial cystitis (p <0.01) and significant increases in signal intensity in anterior bladder regions (p <0.001). Kurtosis (shape of probability distribution) and skewness (measure of probability distribution asymmetry) were associated with contrast enhancement in total bladders in patients with interstitial cystitis vs controls (p <0.05). Regarding symptomatology interstitial cystitis cases differed significantly from controls on the SF-36®, PUF (Pelvic Pain and Urgency/Frequency) and ICPI (Interstitial Cystitis Problem Index) questionnaires with no overlap in the score range in each group. ICSI (Interstitial Cystitis Symptom Index) differed significantly but with a slight overlap in the range of scores. Data suggest that contrast enhanced magnetic resonance imaging provides an objective, quantifiable measurement

Unusual scarring patterns on cardiac magnetic resonance imaging: A potentially treatable etiology not to be missed.

PubMed

Jordan, Andrew; Lyne, Jonathan; Wong, Tom

2010-04-01

A case of cardiomyopathy and ventricular tachycardia previously assumed to be idiopathic in origin is described. Investigation with cardiac magnetic resonance imaging prompted the diagnosis and successful treatment of an underlying disorder based on typical scarring patterns seen with late gadolinium enhancement. The present report suggests that clinicians should have a low threshold for actively excluding this condition in patients presenting with cardiomyopathy, even in the absence of other disease features, particularly if typical scarring patterns are found on cardiac magnetic resonance imaging because disease-specific therapy appears to significantly improve both symptoms and prognosis.

The Use of Gadolinium-Carbon Nanostructures to Magnetically Enhance Stem Cell Retention for Cellular Cardiomyoplasty

PubMed Central

Tran, Lesa A.; Hernández-Rivera, Mayra; Berlin, Ari N.; Zheng, Yi; Sampaio, Luiz; Bové, Christina; Cabreira-Hansen, Maria da Graça; Willerson, James T.; Perin, Emerson C.; Wilson, Lon J.

2014-01-01

In this work, the effectiveness of using Gadonanotubes (GNTs) with an external magnetic field to improve retention of transplanted adult mesenchymal stem cells (MSCs) during cellular cardiomyoplasty was evaluated. As a high-performance T1-weighted magnetic resonance imaging (MRI) cell tracking label, the GNTs are gadolinium-loaded carbon nanotube capsules that render MSCs magnetic when internalized. MSCs were internally labeled with either superparamagnetic GNTs or colloidal diamagnetic lutetium (Lu). In vitro cell rolling assays and ex vivo cardiac perfusion experiments qualitatively demonstrated increased magnetic-assisted retention of GNT-labeled MSCs. Subsequent in vivo epicardial cell injections were performed around a 1.3 T NdFeB ring magnet sutured onto the left ventricle of female juvenile pigs (n = 21). Cell dosage, magnet exposure time, and endpoints were varied to evaluate the safety and efficacy of the proposed therapy. Quantification of retained cells in collected tissues by elemental analysis (Gd or Lu) showed that the external magnet helped retain nearly three times more GNT-labeled MSCs than Lu-labeled cells. The sutured magnet was tolerated for up to 168 hours; however, an inflammatory response to the magnet was noted after 48 hours. These proof-of-concept studies support the feasibility and value of using GNTs as a magnetic nanoparticle facilitator to improve cell retention during cellular cardiomyoplasty. PMID:24148239

Delayed gadolinium-enhanced MRI of the fibrocartilage disc of the temporomandibular joint--a feasibility study.

PubMed

Pittschieler, Elisabeth; Szomolanyi, Pavol; Schmid-Schwap, Martina; Weber, Michael; Egerbacher, Monika; Traxler, Hannes; Trattnig, Siegfried

2014-12-01

To 1) test the feasibility of delayed Gadolinium-Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) at 3 T in the temporomandibular joint (TMJ) and 2) to determine the optimal delay for measurements of the TMJ disc after i.v. contrast agent (CA) administration. MRI of the right and left TMJ of six asymptomatic volunteers was performed at 3 T using a dedicated coil. 2D inversion recovery (2D-IR) sequences were performed at 4 time points covering 120 minutes and 3D gradient-echo (3D GRE) dual flip-angle sequences were performed at 14 time points covering 130 minutes after the administration of 0.2 mmol/kg of Gd-diethylenetriamine pentaacetic acid ion (Gd-DTPA)(2-), i.e., 0.4 mL of Magnevist™ per kg body weight. Pair-wise tests were used to assess differences between pre-and post-contrast T1 values. 2D-IR sequences showed a statistically significant drop (p<0.001) in T1 values after i.v. CA administration. The T1 drop of 50% was reached 60 minutes after bolus injection in the TMJ disc. The 3D GRE dual flip-angle sequences confirmed these results and show plateau of T1 after 60 minutes. T1(Gd) maps calculated from dGEMRIC data allow in vivo assessment of the fibrocartilage disc of the TMJ. The recommended measurement time for dGEMRIC in the TMJ after i.v. CA administration is from 60 to 120 minutes. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Measuring hepatic functional reserve using T1 mapping of Gd-EOB-DTPA enhanced 3T MR imaging: A preliminary study comparing with 99mTc GSA scintigraphy and signal intensity based parameters.

PubMed

Nakagawa, Masataka; Namimoto, Tomohiro; Shimizu, Kie; Morita, Kosuke; Sakamoto, Fumi; Oda, Seitaro; Nakaura, Takeshi; Utsunomiya, Daisuke; Shiraishi, Shinya; Yamashita, Yasuyuki

2017-07-01

To determine the utility of liver T1-mapping on gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic acid (Gd-EOB-DTPA) enhanced magnetic resonance (MR) imaging for the measurement of liver functional reserve compared with the signal intensity (SI) based parameters, technetium-99m-galactosyl serum albumin ( 99m Tc-GSA) scintigraphy and indocyanine green (ICG) clearance. This retrospective study included 111 patients (Child-Pugh-A 90; -B 21) performed with both Gd-EOB-DTPA enhanced liver MR imaging and 99m Tc-GSA (76 patients with ICG). Receiver operating characteristic (ROC) curve analysis was performed to compare diagnostic performances of T1-relaxation-time parameters [pre-(T1pre) and post-contrast (T1hb) Gd-EOB-DTPA], SI based parameters [relative enhancement (RE), liver-to-muscle-ratio (LMR), liver-to-spleen-ratio (LSR)] and 99m Tc-GSA scintigraphy blood clearance index (HH15)] for Child-Pugh classification. Pearson's correlation was used for comparisons among T1-relaxation-time parameters, SI-based parameters, HH15 and ICG. A significant difference was obtained for Child-Pugh classification with T1hb, ΔT1, all SI based parameters and HH15. T1hb had the highest AUC followed by RE, LMR, LSR, ΔT1, HH15 and T1pre. The correlation coefficients with HH15 were T1pre 0.22, T1hb 0.53, ΔT1 -0.38 of T1 relaxation parameters; RE -0.44, LMR -0.45, LSR -0.43 of SI-based parameters. T1hb was highest for correlation with HH15. The correlation coefficients with ICG were T1pre 0.29, T1hb 0.64, ΔT1 -0.42 of T1 relaxation parameters; RE -0.50, LMR -0.61, LSR -0.58 of SI-based parameters; 0.64 of HH15. Both T1hb and HH15 were highest for correlation with ICG. T1 relaxation time at post-contrast of Gd-EOB-DTPA (T1hb) was strongly correlated with ICG clearance and moderately correlated HH15 with 99m Tc-GSA. T1hb has the potential to provide robust parameter of liver functional reserve. Copyright © 2017 Elsevier B.V. All rights reserved.

Ultrasound guidance to perform intra-articular injection of gadolinium-based contrast material for magnetic resonance arthrography as an alternative to fluoroscopy: the time is now.

PubMed

Messina, Carmelo; Banfi, Giuseppe; Aliprandi, Alberto; Mauri, Giovanni; Secchi, Francesco; Sardanelli, Francesco; Sconfienza, Luca Maria

2016-05-01

Magnetic resonance (MR) imaging has been definitively established as the reference standard in the evaluation of joints in the body. Similarly, magnetic resonance arthrography has emerged as a technique that has been proven to increase significantly the diagnostic performance if compared with conventional MR imaging, especially when dealing with fibrocartilage and articular cartilage abnormalities. Diluted gadolinium can be injected in the joint space using different approaches: under palpation using anatomic landmarks or using an imaging guidance, such as fluoroscopy, computed tomography, or ultrasound. Fluoroscopy has been traditionally used, but the involvement of ionizing radiation should represent a remarkable limitation of this modality. Conversely, ultrasound has emerged as a feasible, cheap, quick, and radiation-free modality that can be used to inject joints, with comparable accuracy of fluoroscopy. In the present paper, we discuss the advantages and disadvantages of using fluoroscopy or ultrasound in injecting gadolinium-based contrast agents in joints to perform magnetic resonance arthrography, also in view of the new EuroSAFE Imaging initiative promoted by the European Society of Radiology and the recent updates to the European Atomic Energy Community 2013/59 directive on the medical use of ionizing radiation. • Intra-articular contrast agent injection can be performed using different imaging modalities • Fluoroscopy is widely used, but uses ionizing radiation • Ultrasound is an accurate, quick, and radiation-free modality for joint injection • X-rays should be avoided when other radiation-free modalities can be used.

Interaction of magnetic resonators studied by the magnetic field enhancement

NASA Astrophysics Data System (ADS)

Hou, Yumin

2013-12-01

It is the first time that the magnetic field enhancement (MFE) is used to study the interaction of magnetic resonators (MRs), which is more sensitive than previous parameters-shift and damping of resonance frequency. To avoid the coherence of lattice and the effect of Bloch wave, the interaction is simulated between two MRs with same primary phase when the distance is changed in the range of several resonance wavelengths, which is also compared with periodic structure. The calculated MFE oscillating and decaying with distance with the period equal to resonance wavelength directly shows the retardation effect. Simulation also shows that the interaction at normal incidence is sensitive to the phase correlation which is related with retardation effect and is ultra-long-distance interaction when the two MRs are strongly localized. When the distance is very short, the amplitude of magnetic resonance is oppressed by the strong interaction and thus the MFE can be much lower than that of single MR. This study provides the design rules of metamaterials for engineering resonant properties of MRs.

In vivo cleavage rate of a dextran-bound magnetic resonance imaging contrast agent: preparation and intravascular pharmacokinetic characteristics in the rabbit.

PubMed

Hals, Petter Arnt; Sontum, Per Christian; Holtz, Eckart; Klaveness, Jo; Rongved, Pål

2013-02-01

Earlier described dextran-based contrast agents for magnetic resonance imaging (MRI) comprising the gadolinium chelate diethylenetriamine pentaacetic acid (GdDTPA, 1) have shown significantly shorter in vivo contrast duration in rat than what would be expected from the initial average molecular weight (Mw) of the dextran fraction (71.4 kD). To investigate this further, four dextran fractions with given initial average molecular weight (Mw) of 10.4, 41.0, 71.4 and 580 kD were used as starting material to prepare products 2-5 where one of the carboxylic acid functionalities in GdDTPA was used as a direct covalent ester linker to hydroxyl groups in dextrans. A fifth derivative (6) was an amide-ester bound β-alanine-DTPAGd conjugate with dextran having Mw 71.4 kD. The reference compound GdDTPA (1) and gadoliniumlabelled dextran derivatives 2-6 were injected intravenously in rabbits. Pharmacokinetic parameters showed that when GdDTPA is ester-bound directly to dextran hydroxyls, the cleavage rates of 2-5 were only moderately dependent on the molecular weights of the dextrans, having blood pool half-lives comparable to the low-molecular reference compound (t 1/2,β 0.3 - 0.5 hrs.). Presence of a β-alanine spacer in 6 prolonged the plasma half-life t 1/2,β to 6.9 hours, rendering a blood residence time suitable for blood pool slow release of GdDTPA. Biological cleavage regenerates the clinically acceptable carrier dextran and the β-alanine derivative of GdDTPA, pointing at a clinically acceptable product class for blood-pool contrast in MRI.

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

PubMed

Granata, Vincenza; Cascella, Marco; Fusco, Roberta; dell'Aprovitola, Nicoletta; Catalano, Orlando; Filice, Salvatore; Schiavone, Vincenzo; Izzo, Francesco; Cuomo, Arturo; Petrillo, Antonella

2016-01-01

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.

Gd-EOB-DTPA-enhanced-MR imaging in the inflammation stage of nonalcoholic steatohepatitis (NASH) in mice.

PubMed

Yamada, Tomomi; Obata, Atsushi; Kashiwagi, Yuto; Rokugawa, Takemi; Matsushima, Shuuichi; Hamada, Tadateru; Watabe, Hiroshi; Abe, Kohji

2016-07-01

The purpose of this study is to investigate the correlation between the liver kinetics of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) and liver histopathology in a mouse model of NASH by using dynamic contrast-enhanced MRI. Twenty male C57/BL6 mice aged 8weeks were fed a methionine-choline-deficient (MCD) diet for 2, 4 and 6weeks (MCD groups: MCD 2w, 4w, or 6w). Gd-EOB-DTPA-enhanced MR imaging of the liver was performed at 2, 4 and 6weeks after the MCD feeding. The signal intensity of the liver was obtained from dynamic MR images and relative enhancement (RE), and the time to maximum RE (Tmax) and half-life of elimination RE (T1/2) were calculated. After MRI scan, histopathological scores of hepatic steatosis and inflammation and blood biochemistry data, such as aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels, were obtained. Plasma AST and ALT levels were significantly increased in mice fed MCD. Histopathological scores indicated that steatohepatitis progressed with the MCD feeding period from 2 to 6weeks, but significant fibrosis was observed only in mice fed MCD for 6weeks. Gd-EOB-DTPA-enhanced MRI showed that Tmax was significantly prolonged in the livers of the 6-week group compared to the control group (control, 4.0±0.7min; MCD 6w, 12.1±1.6min), although there was no alteration in the 2- and 4-week groups. T1/2 was significantly prolonged in mice fed MCD for 4 and 6weeks compared to the control group (control, 19.9±2.0min; MCD 4w, 46.7±8.7min; MCD 6w, 65.4±8.8min). The parameters of Gd-EOB-DTPA kinetics (Tmax and T1/2) in the liver were positively correlated with the liver histopathological score (steatosis vs Tmax, rho=0.69, P=0.0007; inflammation vs Tmax, rho=0.66, P=0.00155; steatosis vs T1/2, rho=0.77, P<0.0001; inflammation vs T1/2, rho=0.73, P=0.0003). The liver kinetics of Gd-EOB-DTPA correlated well with the inflammation score in the mouse model of NASH, suggesting the possibility of

A pyrophosphate-responsive gadolinium(III) MRI contrast agent.

PubMed

Surman, Andrew J; Bonnet, Célia S; Lowe, Mark P; Kenny, Gavin D; Bell, Jimmy D; Tóth, Eva; Vilar, Ramon

2011-01-03

This study shows that the relaxivity and optical properties of functionalised lanthanide-DTPA-bis-amide complexes (lanthanide=Gd(3+) and Eu(3+) , DTPA=diethylene triamine pentaacetic acid) can be successfully modulated by addition of specific anions, without direct Ln(3+) /anion coordination. Zinc(II)-dipicolylamine moieties, which are known to bind strongly to phosphates, were introduced in the amide "arms" of these ligands, and the interaction of the resulting Gd-Zn(2) complexes with a range of anions was screened by using indicator displacement assays (IDAs). Considerable selectivity for polyphosphorylated species (such as pyrophosphate and adenosine-5'-triphosphate (ATP)) over a range of other anions (including monophosphorylated anions) was apparent. In addition, we show that pyrophosphate modulates the relaxivity of the gadolinium(III) complex, this modulation being sufficiently large to be observed in imaging experiments. To establish the binding mode of the pyrophosphate and gain insight into the origin of the relaxometric modulation, a series of studies including UV/Vis and emission spectroscopy, luminescence lifetime measurements in H(2) O and D(2) O, (17) O and (31) P NMR spectroscopy and nuclear magnetic resonance dispersion (NMRD) studies were carried out. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimization of hepatobiliary phase delay time of Gd-EOB-DTPA-enhanced magnetic resonance imaging for identification of hepatocellular carcinoma in patients with cirrhosis of different degrees of severity.

PubMed

Wu, Jian-Wei; Yu, Yue-Cheng; Qu, Xian-Li; Zhang, Yan; Gao, Hong

2018-01-21

To optimize the hepatobiliary phase delay time (HBP-DT) of Gd-EOB-DTPA-enhanced magnetic resonance imaging (GED-MRI) for more efficient identification of hepatocellular carcinoma (HCC) occurring in different degrees of cirrhosis assessed by Child-Pugh (CP) score. The liver parenchyma signal intensity (LPSI), the liver parenchyma (LP)/HCC signal ratios, and the visibility of HCC at HBP-DT of 5, 10, 15, 20, and 25 min ( i.e ., DT-5, DT-10, DT-15, DT-20, and DT-25 ) after injection of Gd-EOB-DTPA were collected and analyzed in 73 patients with cirrhosis of different degrees of severity (including 42 patients suffering from HCC) and 18 healthy adult controls. The LPSI increased with HBP-DT more significantly in the healthy group than in the cirrhosis group ( F = 17.361, P < 0.001). The LP/HCC signal ratios had a significant difference ( F = 12.453, P < 0.001) among various HBP-DT points, as well as between CP-A and CP-B/C subgroups ( F = 9.761, P < 0.001). The constituent ratios of HCC foci identified as obvious hypointensity (+++), moderate hypointensity (++), and mild hypointensity or isointensity (+/-) kept stable from DT-10 to DT-25: 90.6%, 9.4%, and 0.0% in the CP-A subgroup; 50.0%, 50.0%, and 0.0% in the CP-B subgroup; and 0.0%, 0.0%, and 100.0% in the CP-C subgroup, respectively. The severity of liver cirrhosis has significant negative influence on the HCC visualization by GED-MRI. DT-10 is more efficient and practical than other HBP-DT points to identify most of HCC foci emerging in CP-A cirrhosis, as well as in CP-B cirrhosis; but an HBP-DT of 15 min or longer seems more appropriate than DT-10 for visualization of HCC in patients with CP-C cirrhosis.

Templated assembly of albumin-based nanoparticles for simultaneous gene silencing and magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Mertz, Damien; Affolter-Zbaraszczuk, Christine; Barthès, Julien; Cui, Jiwei; Caruso, Frank; Baumert, Thomas F.; Voegel, Jean-Claude; Ogier, Joelle; Meyer, Florent

2014-09-01

In this article, we address the design of innovative human serum albumin (HSA)-based nanoparticles loaded with silencing RNA and grafted with gadolinium complexes having average sizes ranging from ca. 50 to 150 nm according to the siRNA/HSA composition. The non-covalent siRNA/HSA assembly is formed on isobutyramide-modified mesoporous silica and the self-supported HSA-based nanoparticles are obtained following the silica template dissolution. These original protein particles provide simultaneous magnetic resonance imaging contrast enhancement and cellular in vitro gene silencing.In this article, we address the design of innovative human serum albumin (HSA)-based nanoparticles loaded with silencing RNA and grafted with gadolinium complexes having average sizes ranging from ca. 50 to 150 nm according to the siRNA/HSA composition. The non-covalent siRNA/HSA assembly is formed on isobutyramide-modified mesoporous silica and the self-supported HSA-based nanoparticles are obtained following the silica template dissolution. These original protein particles provide simultaneous magnetic resonance imaging contrast enhancement and cellular in vitro gene silencing. Electronic supplementary information (ESI) available: Experimental details and supporting Fig. S1-S4. See DOI: 10.1039/c4nr02623c

Deep Photoacoustic/Luminescence/Magnetic Resonance Multimodal Imaging in Living Subjects Using High-Efficiency Upconversion Nanocomposites.

PubMed

Liu, Yu; Kang, Ning; Lv, Jing; Zhou, Zijian; Zhao, Qingliang; Ma, Lingceng; Chen, Zhong; Ren, Lei; Nie, Liming

2016-08-01

A gadolinium-doped multi-shell upconversion nanoparticle under 800 nm excitation is synthesized with a 10-fold fluorescence-intensity enhancement over that under 980 nm. The nanoformulations exhibit excellent photoacoustic/luminescence/magnetic resonance tri-modal imaging capabilities, enabling visualization of tumor morphology and microvessel distribution at a new imaging depth. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Delayed gadolinium-enhanced MRI of the fibrocartilage disc of the temporomandibular joint – a feasibility study

PubMed Central

Pittschieler, Elisabeth; Szomolanyi, Pavol; Schmid-Schwap, Martina; Weber, Michael; Egerbacher, Monika; Traxler, Hannes; Trattnig, Siegfried

2014-01-01

Objective To 1) test the feasibility of delayed Gadolinium-Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) at 3 T in the temporomandibular joint (TMJ) and 2) to determine the optimal delay for measurements of the TMJ disc after i.v. contrast agent (CA) administration. Design MRI of the right and left TMJ of six asymptomatic volunteers was performed at 3 T using a dedicated coil. 2D inversion recovery (2D-IR) sequences were performed at 4 time points covering 120 minutes and 3D gradient-echo (3D GRE) dual flip-angle sequences were performed at 14 time points covering 130 minutes after the administration of 0.2 mmol/kg of Gd-diethylenetriamine pentaacetic acid ion (Gd-DTPA)2-, i.e., 0.4 mL of Magnevist™ per kg body weight. Pair-wise tests were used to assess differences between pre-and post-contrast T1 values. Results 2D-IR sequences showed a statistically significant drop (p < 0.001) in T1 values after i.v. CA administration. The T1 drop of 50% was reached 60 minutes after bolus injection in the TMJ disc. The 3D GRE dual flip-angle sequences confirmed these results and show plateau of T1 after 60 minutes. Conclusions T1(Gd) maps calculated from dGEMRIC data allow in vivo assessment of the fibrocartilage disc of the TMJ. The recommended measurement time for dGEMRIC in the TMJ after i.v. CA administration is from 60 to 120 minutes. PMID:25131629

Magnetic resonance imaging in local staging of endometrial carcinoma: diagnostic performance, pitfalls, and literature review.

PubMed

Zandrino, Franco; La Paglia, Ernesto; Musante, Francesco

2010-01-01

To assess the diagnostic accuracy of magnetic resonance imaging in local staging of endometrial carcinoma, and to review the results and pitfalls described in the literature. Thirty women with a histological diagnosis of endometrial carcinoma underwent magnetic resonance imaging. Unenhanced T2-weighted and dynamic contrast-enhanced Ti-weighted sequences were obtained. Hysterectomy and salpingo-oophorectomy was performed in all patients. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated for the detection of deep myometrial and cervical infiltration. For deep myometrial infiltration T2-weighted sequences reached a sensitivity of 85%, specificity of 76%, PPV of 73%, NVP of 87%, and accuracy of 80%, while contrast-enhanced scans reached a sensitivity of 90%, specificity of 80%, PPV of 82%, NPV of 89%, and accuracy of 85%. For cervical infiltration T2-weighted sequences reached a sensitivity of 75%, specificity of 88%, PPV of 50%, NPV of 96%, and accuracy of 87%, while contrast-enhanced scans reached a sensitivity of 100%, specificity of 94%, PPV of 75%, NPV of 100%, and accuracy of 95%. Unenhanced and dynamic gadolinium-enhanced magnetic resonance allows accurate assessment of myometrial and cervical infiltration. Information provided by magnetic resonance imaging can define prognosis and management.

Factors predicting aggressiveness of non-hypervascular hepatic nodules detected on hepatobiliary phase of gadolinium ethoxybenzyl diethylene-triamine-pentaacetic-acid magnetic resonance imaging.

PubMed

Kanefuji, Tsutomu; Takano, Toru; Suda, Takeshi; Akazawa, Kouhei; Yokoo, Takeshi; Kamimura, Hiroteru; Kamimura, Kenya; Tsuchiya, Atsunori; Takamura, Masaaki; Kawai, Hirokazu; Yamagiwa, Satoshi; Aoyama, Hidefumi; Nomoto, Minoru; Terai, Shuji

2015-04-21

To establish a prognostic formula that distinguishes non-hypervascular hepatic nodules (NHNs) with higher aggressiveness from less hazardous one. Seventy-three NHNs were detected in gadolinium ethoxybenzyl diethylene-triamine-pentaacetic-acid magnetic resonance imaging (Gd-EOB-DTPA-MRI) study and confirmed to change 2 mm or more in size and/or to gain hypervascularity. All images were interpreted independently by an experienced, board-certified abdominal radiologist and hepatologist; both knew that the patients were at risk for hepatocellular carcinoma development but were blinded to the clinical information. A formula predicting NHN destiny was developed using a generalized estimating equation model with thirteen explanatory variables: age, gender, background liver diseases, Child-Pugh class, NHN diameter, T1-weighted imaging/T2-weighted imaging detectability, fat deposition, lower signal intensity in arterial phase, lower signal intensity in equilibrium phase, α-fetoprotein, des-γ-carboxy prothrombin, α-fetoprotein-L3, and coexistence of classical hepatocellular carcinoma. The accuracy of the formula was validated in bootstrap samples that were created by resampling of 1000 iterations. During a median follow-up period of 504 d, 73 NHNs with a median diameter of 9 mm (interquartile range: 8-12 mm) grew or shrank by 68.5% (fifty nodules) or 20.5% (fifteen nodules), respectively, whereas hypervascularity developed in 38.4% (twenty eight nodules). In the fifteen shrank nodules, twelve nodules disappeared, while 11.0% (eight nodules) were stable in size but acquired vascularity. A generalized estimating equation analysis selected five explanatories from the thirteen variables as significant factors to predict NHN progression. The estimated regression coefficients were 0.36 for age, 6.51 for lower signal intensity in arterial phase, 8.70 or 6.03 for positivity of hepatitis B virus or hepatitis C virus, 9.37 for des-γ-carboxy prothrombin, and -4.05 for fat

Synthesis of Tumor-avid Photosensitizer-Gd(III)DTPA conjugates: impact of the number of gadolinium units in T1/T2 relaxivity, intracellular localization, and photosensitizing efficacy.

PubMed

Goswami, Lalit N; White, William H; Spernyak, Joseph A; Ethirajan, Manivannan; Chen, Yihui; Missert, Joseph R; Morgan, Janet; Mazurchuk, Richard; Pandey, Ravindra K

2010-05-19

To develop novel bifunctional agents for tumor imaging (MR) and photodynamic therapy (PDT), certain tumor-avid photosensitizers derived from chlorophyll-a were conjugated with variable number of Gd(III)aminobenzyl DTPA moieties. All the conjugates containing three or six gadolinium units showed significant T(1) and T(2) relaxivities. However, as a bifunctional agent, the 3-(1'-hexyloxyethyl)pyropheophorbide-a (HPPH) containing 3Gd(III) aminophenyl DTPA was most promising with possible applications in tumor-imaging and PDT. Compared to HPPH, the corresponding 3- and 6Gd(III)aminobenzyl DTPA conjugates exhibited similar electronic absorption characteristics with a slightly decreased intensity of the absorption band at 660 nm. However, compared to HPPH, the excitation of the broad "Soret" band (near 400 nm) of the corresponding 3Gd(III)aminobenzyl-DTPA analogues showed a significant decrease in the fluorescence intensity at 667 nm.

Comparative in vivo mucoadhesion studies of thiomer formulations using magnetic resonance imaging and fluorescence detection.

PubMed

Albrecht, K; Greindl, M; Kremser, C; Wolf, C; Debbage, P; Bernkop-Schnürch, A

2006-09-28

The aim of this study was to compare different oral delivery systems based on the thiolated polymer polycarbophil-cysteine (PCP-Cys) and to provide evidence for the validity of the hypothesis that unhydrated polymers provide better mucoadhesion in vivo. To achieve dry polymer application, a new, experimental dosage form named Eutex (made of Eudragit L100-55 and latex) capsule has been developed. Magnetic resonance imaging was used to localize the point of release of the thiolated polymer from the application forms via the positive magnetic resonance signal from a gadolinium complex (Gd-DTPA). In vivo mucoadhesion was determined by ascertaining the residence time of the fluorescence-tagged thiomer on intestinal mucosa after 3 h. Results showed that in comparison to conventional application forms the Eutex capsules led to 1.9-fold higher mucoadhesive properties of PCP-Cys when compared to application with a conventional enteric-coated capsule, and to 1.4-fold higher mucoadhesion when compared to administration with an enteric-coated tablet of the thiomer. The findings of this study should contribute to the understanding of mucoadhesion and mucoadhesion influencing parameters in vivo and should therefore be of considerable interest for the development of future mucoadhesive oral drug delivery dosage forms.

An update on clinical applications of magnetic nanoparticles for increasing the resolution of magnetic resonance imaging.

PubMed

Zeinali Sehrig, Fatemeh; Majidi, Sima; Asvadi, Sahar; Hsanzadeh, Arash; Rasta, Seyed Hossein; Emamverdy, Masumeh; Akbarzadeh, Jamshid; Jahangiri, Sahar; Farahkhiz, Shahrzad; Akbarzadeh, Abolfazl

2016-11-01

Today, technologies based on magnetic nanoparticles (MNPs) are regularly applied to biological systems with diagnostic or therapeutic aims. Nanoparticles made of the elements iron (Fe), gadolinium (Gd) or manganese (Mn) are generally used in many diagnostic applications performed under magnetic resonance imaging (MRI). Similar to molecular-based contrast agents, nanoparticles can be used to increase the resolution of imaging while offering well biocompatibility, poisonousness and biodistribution. Application of MNPs enhanced MRI sensitivity due to the accumulation of iron in the liver caused by discriminating action of the hepatobiliary system. The aim of this study is about the use, properties and advantages of MNPs in MRI.

Gd³⁺ Tethered Gold Nanorods for Combined Magnetic Resonance Imaging and Photo-Thermal Therapy.

PubMed

Pitchaimani, Arunkumar; Duong, Tuyen; Nguyen, Thanh; Maurmann, Leila; Key, Jaehong; Bossmann, Stefan H; Aryal, Santosh

2017-04-01

Near infrared (NIR) mediated photothermal therapy and magnetic resonance imaging (MRI) are promising treatment and imaging modalities in the field of cancer theranostics. Gold nanorods are the first choice of materials for NIR-mediated photothermal therapy due to their strong localized surface plasmon resonance (LSPR) at NIR region. Similarly, gadolinium based MRI contrast agents have an ability to increase the ionic and molecular relaxivity, thereby enhancing the solvent proton relaxation rate resulting in contrast enhancement. Herein, the effort has been made to engineer a dual front theranostic agent with combined photothermal and magnetic resonance imaging capacity using gadolinium tethered gold nanorods (Gd3+-AuNR). NIR-responsive gold nanorods were surface fabricated by means of Au-thiol interaction using a thiolated macrocyclic chelator that chelates Gd3+ ions, and further stabilized by thiolated polyethylene glycol (PEG-SH). The magnetic properties of the Gd3+-AuNR displayed an enhanced r 1 relaxivity of 12.1 mM–1s–1, with higher biological stability, and contrast enhancement in both solution state and in cell pellets. In-vitro (cell-free) and ex-vivo (on pig skin) analysis of the Gd3+-AuNR shows enhanced photothermal properties as equivalent to that of the raw AuNR. Furthermore, Gd3+-AuNR showed competent cellular entry and intracellular distribution as revealed by hyperspectral microscopy. In addition, Gd3+-AuNR also exhibits significant thermal ablation of B16–F10 cells in the presence of NIR. Thus, Gd3+-AuNR features a significant theranostic potential with combined photothermal and imaging modality, suggesting a great potential in anticancer therapy.

Real-time tracking of dissociation of hyperpolarized 89Y-DTPA: a model for degradation of open-chain Gd3+ MRI contrast agents

NASA Astrophysics Data System (ADS)

Ferguson, Sarah; Niedbalski, Peter; Parish, Christopher; Kiswandhi, Andhika; Kovacs, Zoltan; Lumata, Lloyd

Gadolinium (Gd) complexes are widely used relaxation-based clinical contrast agents in magnetic resonance imaging (MRI). Gd-based MRI contrast agents with open-chain ligand such as Gd-DTPA, commercially known as magnevist, are less stable compared to Gd complexes with macrocyclic ligands such as GdDOTA (Dotarem). The dissociation of Gd-DPTA into Gd ion and DTPA ligand under certain biological conditions such as high zinc levels can potentially cause kidney damage. Since Gd is paramagnetic, direct NMR detection of the Gd-DTPA dissociation is quite challenging due to ultra-short relaxation times. In this work, we have investigated Y-DTPA as a model for Gd-DPTA dissociation under high zinc content solutions. Using dissolution dynamic nuclear polarization (DNP), the 89Y NMR signal is amplified by several thousand-fold. Due to the the relatively long T1 relaxation time of 89Y which translates to hyperpolarization lifetime of several minutes, the dissociation of Y-DTPA can be tracked in real-time by hyperpolarized 89Y NMR spectroscopy. Dissociation kinetic rates and implications on the degradation of open-chain Gd3+ MRI contrast agents will be discussed. This work was supported by the U.S. Department of Defense Award Number W81XWH-14-1-0048 and by the Robert A. Welch Foundation research Grant Number AT-1877.

Feasibility of texture analysis for the assessment of biochemical changes in meniscal tissue on T1 maps calculated from delayed gadolinium-enhanced magnetic resonance imaging of cartilage data: comparison with conventional relaxation time measurements.

PubMed

Mayerhoefer, Marius E; Welsch, Goetz H; Riegler, Georg; Mamisch, Tallal C; Materka, Andrzej; Weber, Michael; El-Rabadi, Karem; Friedrich, Klaus M; Dirisamer, Albert; Trattnig, Siegfried

2010-09-01

To (1) establish the feasibility of texture analysis for the in vivo assessment of biochemical changes in meniscal tissue on delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC), and (2) compare textural with conventional T1 relaxation time measurements calculated from dGEMRIC data ("T1(Gd) relaxation times"). We enrolled 10 asymptomatic volunteers (7 men and 3 women; mean age, 27.2 +/- 4.5 years), without a history of meniscus damage, in our study. MRI of the right knee was performed at 3.0 T. An isotropic, 3-dimensional (3D), double-echo steady-state sequences was used for morphologic evaluation, and a dual flip angle 3D gradient echo sequence was used for T1(Gd) mapping. All MRI scans were performed 90 minutes after injection of 0.2 mmol/kg of Gd-diethylenetriamine pentaacetic acid (DTPA), and subsequently, during application of a compressive force (50% of the body weight) in the axial direction. Regions of interest, covering the central portions of the posterior horn of the medial meniscus, were defined on 3 adjacent sagittal sections. Based on the relaxation time maps, mean T1(Gd), as well as the T1(Gd) texture features derived from the co-occurrence matrix (COC: Angular Second Moment, Entropy, Inverse Difference Moment) and wavelet transform (WAV: WavEnLL, WavEnHL, WavEnHH, WavEnLH), were calculated. Paired t tests were used to assess differences between baseline and compression, and intraclass correlation coefficients (ICC) were calculated to establish the intrarater reliability of the measurements. Mean T1(Gd) (-67.3 ms, P = 0.011), Angular Second Moment (-0.0002, P = 0.009), Entropy (+0.033, P = 0.025), WavEnLL (+1011.16, P = 0.002), WavEnHL (+18.64, P = 0.012), and WavEnLH (+72.74, P = 0.035) differed significantly between baseline and compression. Intrarater reliability was substantial for mean T1(Gd) relaxation times (ICC = 0.99-1.0), and also for T1(Gd) co-occurrence matrix (ICC = 0.63-0.92) and WAV (ICC = 0.86-0.98) features

Influence of acquired obesity on coronary vessel wall late gadolinium enhancement in discordant monozygote twins.

PubMed

Makowski, Marcus R; Jansen, Christian H P; Ebersberger, Ullrich; Schaeffter, Tobias; Razavi, Reza; Mangino, Massimo; Spector, Tim D; Botnar, Rene M; Greil, Gerald F

2017-11-01

The aim of this study was to investigate the impact of BMI on late gadolinium enhancement (LGE) of the coronary artery wall in identical monozygous twins discordant for BMI. Coronary LGE represents a useful parameter for the detection and quantification of atherosclerotic coronary vessel wall disease. Thirteen monozygote female twin pairs (n = 26) with significantly different BMIs (>1.6 kg/m2) were recruited out of >10,000 twin pairs (TwinsUK Registry). A coronary 3D-T2prep-TFE MR angiogram and 3D-IR-TFE vessel wall scan were performed prior to and following the administration of 0.2 mmol/kg of Gd-DTPA on a 1.5 T MR scanner. The number of enhancing coronary segments and contrast to noise ratios (CNRs) of the coronary wall were quantified. An increase in BMI was associated with an increased number of enhancing coronary segments (5.3 ± 1.5 vs. 3.5 ± 1.6, p < 0.0001) and increased coronary wall enhancement (6.1 ± 1.1 vs. 4.8 ± 0.9, p = 0.0027) compared to matched twins with lower BMI. This study in monozygous twins indicates that acquired factors predisposing to obesity, including lifestyle and environmental factors, result in increased LGE of the coronary arteries, potentially reflecting an increase in coronary atherosclerosis in this female study population. • BMI-discordant twins allow the investigation of the influence of lifestyle factors independent from genetic confounders. • Only thirteen obesity-discordant twins were identified underlining the strong genetic component of BMI. • In female twins, a BMI increase is associated with increased coronary late gadolinium enhancement. • Increased late gadolinium enhancement in the coronary vessel wall potentially reflects increased atherosclerosis.

Magnetic resonance imaging of osteosarcoma using a bis(alendronate)-based bone-targeted contrast agent.

PubMed

Ge, Pingju; Sheng, Fugeng; Jin, Yiguang; Tong, Li; Du, Lina; Zhang, Lei; Tian, Ning; Li, Gongjie

2016-12-01

Magnetic resonance (MR) is currently used for diagnosis of osteosarcoma but not well even though contrast agents are administered. Here, we report a novel bone-targeted MR imaging contrast agent, Gd 2 -diethylenetriaminepentaacetate-bis(alendronate) (Gd 2 -DTPA-BA) for the diagnosis of osteosarcoma. It is the conjugate of a bone cell-seeking molecule (i.e., alendronate) and an MR imaging contrast agent (i.e., Gd-DTPA). Its physicochemical parameters were measured, including pK a , complex constant, and T 1 relaxivity. Its bone cell-seeking ability was evaluated by measuring its adsorption on hydroxyapatite. Hemolysis was investigated. MR imaging and biodistribution of Gd 2 -DTPA-BA and Gd-DTPA were studied on healthy and osteosarcoma-bearing nude mice. Gd 2 -DTPA-BA showed high adsorption on hydroxyapatite, the high MR relaxivity (r 1 ) of 7.613mM -1 s -1 (2.6 folds of Gd-DTPA), and no hemolysis. The MR contrast effect of Gd 2 -DTPA-BA was much higher than that of Gd-DTPA after intravenous injection to the mice. More importantly, the MR imaging of osteosarcoma was significantly improved by Gd 2 -DTPA-BA. The signal intensity of Gd 2 -DTPA-BA reached 120.3% at 50min, equal to three folds of Gd-DTPA. The bone targeting index (bone/blood) of Gd 2 -DTPA-BA in the osteosarcoma-bearing mice was very high to 130 at 180min. Furthermore, the contrast enhancement could also be found in the lung due to metastasis of osteosarcoma. Gd 2 -DTPA-BA plays a promising role in the diagnoses of osteosacomas, including the primary bone tumors and metastases. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Magnetic nanoparticles modified with DTPA-AMC-rare earth for fluorescent and magnetic resonance dual mode imaging.

PubMed

Liu, Zengchen; Li, Bo; Wang, Baodui; Yang, Zhengyin; Wang, Qin; Li, Tianrong; Qin, Dongdong; Li, Yong; Wang, Mingfang; Yan, Mihui

2012-07-28

In the present study, we report new water-soluble cell fluorescence imaging and contrast agents that are based on DTPA-AMC(7-amino-4-methyl coumarin)-Eu(3+) and DTPA-AMC(7-amino-4-methyl coumarin)-Gd(3+) compounds conjugated to Fe(3)O(4) NPs via a PEG-NH(2) linker. The novel Fe(3)O(4) NP-conjugates present two main advantages for cell fluorescence labelling: water solubility and targeting ability. The in vitro experiments demonstrate that water-soluble Fe(3)O(4) NPs-DBI-PEG-NH-DTPA-AMC(7-amino-4-methyl coumarin)-Eu(3+) has excellent cell permeating activity. Moreover, the relaxation rate test of Fe(3)O(4) NPs-DBI-PEG-NH-DTPA-AMC(7-amino-4-methyl coumarin)-Gd(3+) shows a higher T1 relaxation effect than traditional DTPA-Gd(3+) MRI agents. According to in vivo liver MRI experiments, better contrast of the liver was achieved after addition of Fe(3)O(4) NPs-DBI-PEG-NH-DTPA-AMC(7-amino-4-methyl coumarin)-Gd(3+). The results will provide a significant guide for researchers exploring the biomedical applications of superparamagnetic Fe(3)O(4) NPs.

Gadolinium-Encapsulating Iron Oxide Nanoprobe as Activatable NMR/MRI Contrast Agent

PubMed Central

Santra, Santimukul; Jativa, Samuel D.; Kaittanis, Charalambos; Normand, Guillaume; Grimm, Jan; Perez, J. Manuel

2012-01-01

Herein we report a novel gadolinium-encapsulating iron oxide nanoparticle-based activatable NMR/MRI nanoprobe. In our design, Gd-DTPA is encapsulated within the polyacrylic acid (PAA) polymer coating of a superparamagnetic iron oxide nanoparticle (IO-PAA) yielding a composite magnetic nanoprobe (IO-PAA-Gd-DTPA) with quenched longitudinal spin-lattice magnetic relaxation (T1). Upon release of the Gd-DTPA complex from the nanoprobe's polymeric coating in acidic media, an increase in the T1 relaxation rate (1/T1) of the composite magnetic nanoprobe was observed, indicating a dequenching of the nanoprobe with a corresponding increase in the T1-weighted MRI signal. When a folate-conjugated nanoprobe was incubated in HeLa cells, a cancer cell line overexpressing folate receptors, an increase in the 1/T1 signal was observed. This result suggests that upon receptor-mediated internalization, the composite magnetic nanoprobe degraded within the cell's lysosome acidic (pH = 5.0) environment, resulting in an intracellular release of Gd-DTPA complex with subsequent T1 activation. No change in T1 was observed when the Gd-DTPA complex was chemically conjugated on the surface of the nanoparticle's polymeric coating or when encapsulated in the polymeric coating of a non-magnetic nanoparticle. These results confirmed that the observed (T1) quenching of the composite magnetic nanoprobe is due to the encapsulation and close proximity of the Gd ion to the nanoparticles superparamagnetic iron oxide (IO) core. In addition, when an anticancer drug (Taxol) was co-encapsulated with the Gd-DTPA within the folate receptor targeting composite magnetic nanoprobe, the T1 activation of the probe coincide with the rate of drug release and corresponding cytotoxic effect in cell culture studies. Taken together, these results suggest that our activatable T1 nanoagent could be of great importance for the detection of acidic tumors and assessment of drug targeting and release by MRI. PMID:22809405

Gadolinium-enhanced versus time-of-flight magnetic resonance angiography: what is the benefit of contrast enhancement in evaluating carotid stenosis?

PubMed

Muhs, Bart E; Gagne, Paul; Wagener, Jael; Baker, Jessica; Ortega, Marta Ramirez; Adelman, Mark A; Cayne, Neal S; Rockman, Caron B; Maldonado, Thomas

2005-11-01

Accurate patient selection based on preoperative imaging is imperative to good risk reduction in patients undergoing carotid endarterectomy (CEA). The goal of this study was to assess the accuracy of gadolinium-enhanced magnetic resonance angiography (GE MRA) versus time-of-flight (TOF) MRA in the work-up of patients undergoing CEA. Patients undergoing CEA between 1999 and 2001 were identified from a prospectively maintained institutional database. GE or TOF MRA was obtained on extracranial carotid arteries (n = 319) in patients undergoing CEA. Stenosis on MRA images was graded as moderate (n = 76) or severe (n = 243) by an attending radiologist who was blind to duplex results. Duplex imaging was performed in an Intersocietal Commission for the Accreditation of Vascular Labs (ICAVL) accredited lab, and stenosis was stratified as moderate (50-79%, n = 76) or high (80-99%, n = 243) grade using University of Washington criteria. For each patient, the degree of stenosis as determined by MRA (GE versus TOF) was compared to percent stenosis on duplex. For moderate-grade lesions, GE MRA concurred with duplex in 11.1% (4/36), underestimated in 2.8% (1/36), and overestimated in 86.1% (31/36) of carotid arteries imaged. TOF MRA concurred with duplex in 35% (14/40), underestimated in 0% (0/40), and overestimated in 65% (26/40) of carotid arteries. High-grade lesions demonstrated improved concordance between MRA and duplex. For these lesions, GE MRA concurred with duplex in 95.6% (130/136) of carotid arteries imaged, never overestimated stenosis (0/136), and underestimated in 4.4% (6/136). TOF MRA concurred with duplex 96.3% (103/107), overestimated stenosis as an occlusion in 0.9% (1/107), and underestimated in 2.8% (3/107). In addition to neck visualization, the GE technique allowed simultaneous aortic arch imaging. This was accomplished in 79.1% (136/172) of all GE MRAs. Simultaneous aortic arch imaging was not technically feasible with TOF MRA. For moderate-grade lesions

Incremental prognostic value of the SYNTAX score to late gadolinium-enhanced magnetic resonance images for patients with stable coronary artery disease.

PubMed

Kato, Shingo; Saito, Naka; Kirigaya, Hidekuni; Gyotoku, Daiki; Iinuma, Naoki; Kusakawa, Yuka; Iguchi, Kohei; Nakachi, Tatsuya; Fukui, Kazuki; Futaki, Masaaki; Iwasawa, Tae; Taguri, Masataka; Kimura, Kazuo; Umemura, Satoshi

2016-06-01

The prognostic significance of the SYNTAX (Synergy between PCI with Taxus and cardiac surgery) score has recently been demonstrated in patients with stable multivessel or left main coronary artery disease (CAD). The present study determines whether adding the SYNTAX score to Framingham risk score (FRS), left ventricular ejection fraction (LVEF) and presence of myocardial infarction (MI) by late gadolinium enhancement (LGE) magnetic resonance imaging can improve the risk stratification in patients with stable CAD. We calculated the SYNTAX score in 161 patients with stable CAD (mean age: 66 ± 10 years old). During a mean follow-up of 2.3 years, 56 (35 %) of 161 patients developed cardiovascular events defined as cardiovascular death, non-fatal MI, cerebral infarction, unstable angina pectoris, hospitalization due to heart failure and revascularization. Multivariate Cox regression analysis selected triglycerides [hazard ratio (HR): 1.005 (95 % confidence interval (CI): 1.001-1.008), p < 0.008], presence of LGE [HR: 6.329 (95 % CI: 2.662-15.05), p < 0.001] and the SYNTAX score [HR: 1.085 (95 % CI: 1.044-1.127), p < 0.001] as risk factors for future cardiovascular events. Adding the SYNTAX score to FRS, EF and LGE significantly improved the net reclassification index (NRI) [40.4 % (95 % CI: 18.1-54.8 %), p < 0.05] with an increase in C-statistics of 0.089 (from 0.707 to 0.796). An increase in C-statistics and significant improvement of NRI showed that adding the SYNTAX score to the FRS, LVEF and LGE incrementally improved risk stratification in patient with stable CAD.

Role of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging in the management of hepatocellular carcinoma: consensus at the Symposium of the 48th Annual Meeting of the Liver Cancer Study Group of Japan.

PubMed

Kudo, Masatoshi; Matsui, Osamu; Sakamoto, Michiie; Kitao, Azusa; Kim, Tonsok; Ariizumi, Shun-ichi; Ichikawa, Tomoaki; Kobayashi, Satoshi; Imai, Yasuharu; Izumi, Namiki; Fujinaga, Yasunari; Arii, Shigeki

2013-01-01

We summarize here the consensus reached at the Symposium of the 48th Annual Meeting of the Liver Cancer Study Group of Japan held in Kanazawa on July 20th and 21st, 2012, on the role of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (EOB-MRI) in the management of hepatocellular carcinoma (HCC). Currently, dynamic CT is the first choice of imaging modality when HCC is suspected. EOB-MRI is useful for differentiation and definitive diagnosis of HCC when dynamic CT/MRI does not show conclusive findings for HCC. In addition, contrast- enhanced ultrasound with Sonazoid is useful for making a decision on whether or not to treat a hypovascular lesion <1 cm when the nodules are shown with low intensity in the hepatocyte phase of EOB-MRI. Furthermore, EOB-MRI should be performed in selected cases of HCC ultrahigh-risk groups every 3-4 months, or EOB-MRI should be performed at least once at the first visit in all HCC ultrahigh-risk groups. Copyright © 2013 S. Karger AG, Basel.

Multiparametric Cardiac Magnetic Resonance Survey in Children With Thalassemia Major: A Multicenter Study.

PubMed

Casale, Maddalena; Meloni, Antonella; Filosa, Aldo; Cuccia, Liana; Caruso, Vincenzo; Palazzi, Giovanni; Gamberini, Maria Rita; Pitrolo, Lorella; Putti, Maria Caterina; D'Ascola, Domenico Giuseppe; Casini, Tommaso; Quarta, Antonella; Maggio, Aurelio; Neri, Maria Giovanna; Positano, Vincenzo; Salvatori, Cristina; Toia, Patrizia; Valeri, Gianluca; Midiri, Massimo; Pepe, Alessia

2015-08-01

Cardiovascular magnetic resonance (CMR) plays a key role in the management of thalassemia major patients, but few data are available in pediatric population. This study aims at a retrospective multiparametric CMR assessment of myocardial iron overload, function, and fibrosis in a cohort of pediatric thalassemia major patients. We studied 107 pediatric thalassemia major patients (61 boys, median age 14.4 years). Myocardial and liver iron overload were measured by T2* multiecho technique. Atrial dimensions and biventricular function were quantified by cine images. Late gadolinium enhancement images were acquired to detect myocardial fibrosis. All scans were performed without sedation. The 21.4% of the patients showed a significant myocardial iron overload correlated with lower compliance to chelation therapy (P<0.013). Serum ferritin ≥2000 ng/mL and liver iron concentration ≥14 mg/g/dw were detected as the best threshold for predicting cardiac iron overload (P=0.001 and P<0.0001, respectively). A homogeneous pattern of myocardial iron overload was associated with a negative cardiac remodeling and significant higher liver iron concentration (P<0.0001). Myocardial fibrosis by late gadolinium enhancement was detected in 15.8% of the patients (youngest children 13 years old). It was correlated with significant lower heart T2* values (P=0.022) and negative cardiac remodeling indexes. A pathological magnetic resonance imaging liver iron concentration was found in the 77.6% of the patients. Cardiac damage detectable by a multiparametric CMR approach can occur early in thalassemia major patients. So, the first T2* CMR assessment should be performed as early as feasible without sedation to tailor the chelation treatment. Conversely, late gadolinium enhancement CMR should be postponed in the teenager age. © 2015 American Heart Association, Inc.

Hepatobiliary magnetic resonance imaging in patients with liver disease: correlation of liver enhancement with biochemical liver function tests.

PubMed

Kukuk, Guido M; Schaefer, Stephanie G; Fimmers, Rolf; Hadizadeh, Dariusch R; Ezziddin, Samer; Spengler, Ulrich; Schild, Hans H; Willinek, Winfried A

2014-10-01

To evaluate hepatobiliary magnetic resonance imaging (MRI) using Gd-EOB-DTPA in relation to various liver function tests in patients with liver disorders. Fifty-one patients with liver disease underwent Gd-EOB-DTPA-enhanced liver MRI. Based on region-of-interest (ROI) analysis, liver signal intensity was calculated using the spleen as reference tissue. Liver-spleen contrast ratio (LSCR) and relative liver enhancement (RLE) were calculated. Serum levels of total bilirubin, gamma glutamyl transpeptidase (GGT), aspartate aminotransferase (AST), alanine aminotransferase (ALT), glutamate dehydrogenase (GLDH), lactate dehydrogenase (LDH), serum albumin level (AL), prothrombin time (PT), creatinine (CR) as well as international normalised ratio (INR) and model for end-stage liver disease (MELD) score were tested for correlation with LSCR and RLE. Pre-contrast LSCR values correlated with total bilirubin (r = -0.39; p = 0.005), GGT (r = -0.37; p = 0.009), AST (r = -0.38; p = 0.013), ALT (r = -0.29; p = 0.046), PT (r = 0.52; p < 0.001), GLDH (r = -0.55; p = 0.044), INR (r = -0.42; p = 0.003), and MELD Score (r = -0.53; p < 0.001). After administration of Gd-EOB-DTPA bilirubin (r = -0.45; p = 0.001), GGT (r = -0.40; p = 0.004), PT (r = 0.54; p < 0.001), AST (r = -0.46; p = 0.002), ALT (r = -0.31; p = 0.030), INR (r = -0.45; p = 0.001) and MELD Score (r = -0.56; p < 0.001) significantly correlated with LSCR. RLE correlated with bilirubin (r = -0.40; p = 0.004), AST (r = -0.38; p = 0.013), PT (r = 0.42; p = 0.003), GGT (r = -0.33; p = 0.020), INR (r = -0.36; p = 0.011) and MELD Score (r = -0.43; p = 0.003). Liver-spleen contrast ratio and relative liver enhancement using Gd-EOB-DTPA correlate with a number of routinely used biochemical liver function tests, suggesting that hepatobiliary MRI may serve as a

Current and potential imaging applications of ferumoxytol for magnetic resonance imaging.

PubMed

Toth, Gerda B; Varallyay, Csanad G; Horvath, Andrea; Bashir, Mustafa R; Choyke, Peter L; Daldrup-Link, Heike E; Dosa, Edit; Finn, John Paul; Gahramanov, Seymur; Harisinghani, Mukesh; Macdougall, Iain; Neuwelt, Alexander; Vasanawala, Shreyas S; Ambady, Prakash; Barajas, Ramon; Cetas, Justin S; Ciporen, Jeremy; DeLoughery, Thomas J; Doolittle, Nancy D; Fu, Rongwei; Grinstead, John; Guimaraes, Alexander R; Hamilton, Bronwyn E; Li, Xin; McConnell, Heather L; Muldoon, Leslie L; Nesbit, Gary; Netto, Joao P; Petterson, David; Rooney, William D; Schwartz, Daniel; Szidonya, Laszlo; Neuwelt, Edward A

2017-07-01

Contrast-enhanced magnetic resonance imaging is a commonly used diagnostic tool. Compared with standard gadolinium-based contrast agents, ferumoxytol (Feraheme, AMAG Pharmaceuticals, Waltham, MA), used as an alternative contrast medium, is feasible in patients with impaired renal function. Other attractive imaging features of i.v. ferumoxytol include a prolonged blood pool phase and delayed intracellular uptake. With its unique pharmacologic, metabolic, and imaging properties, ferumoxytol may play a crucial role in future magnetic resonance imaging of the central nervous system, various organs outside the central nervous system, and the cardiovascular system. Preclinical and clinical studies have demonstrated the overall safety and effectiveness of this novel contrast agent, with rarely occurring anaphylactoid reactions. The purpose of this review is to describe the general and organ-specific properties of ferumoxytol, as well as the advantages and potential pitfalls associated with its use in magnetic resonance imaging. To more fully demonstrate the applications of ferumoxytol throughout the body, an imaging atlas was created and is available online as supplementary material. Published by Elsevier Inc.

Dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) for the assessment of Pc 4-sensitized photodynamic therapy of a U87-derived glioma model in the athymic nude rat

NASA Astrophysics Data System (ADS)

Anka, Ali; Thompson, Paul; Mott, Eric; Sharma, Rahul; Zhang, Ruozhen; Cross, Nathan; Sun, Jiayang; Flask, Chris A.; Oleinick, Nancy L.; Dean, David

2010-02-01

Introduction: Dynamic Contrast-Enhanced-Magnetic Resonance Imaging (DCE-MRI) may provide a means of tracking the outcome of Pc 4-sensitized photodynamic therapy (PDT) in deeply placed lesions (e.g., brain tumors). We previously determined that 150 μL of gadolinium (Gd-DTPA) produces optimal enhancement of U87-derived intracerebral tumors in an athymic nude rat glioma model. We wish to determine how consistently DCE-MRI enhancement will detect an increase in Gd-enhancement of these tumors following Pc 4-PDT. Methods: We injected 2.5 x 105 U87 cells into the brains of 6 athymic nude rats. After 7-8 days pre-Pc 4 PDT peri-tumor DCE-MRI images were acquired on a 7.0T microMRI scanner before and after administration of 150 μL Gd. DCE-MRI scans were repeated on Days 11, 12, and 13 following Pc 4-PDT (Day 8 or 9). Results: Useful DCE-MRI data were obtained for these animals before and after Pc 4- PDT. In the pre-Pc 4-PDT DCE-MRI scans an average normalized peak Gd enhancement was observed in tumor tissue that was 1.297 times greater than baseline (0.035 Standard Error [SE]). The average normalized peak Gd enhancement in the tumor tissue in the scan following PDT (Day 11) was 1.537 times greater than baseline (0.036 SE), a statistically significant increase in enhancement (p = 0.00584) over the pre-PDT level. Discussion: A 150 μL Gd dose appears to provide an unambiguous increase in signal indicating Pc 4-PDT-induced necrosis of the U87-derived tumor. Our DCEMRI protocol may allow the development of a clinically robust, unambiguous, non-invasive technique for the assessment of PDT outcome.

Exploratory use of cardiovascular magnetic resonance imaging in liver transplantation: a one-stop shop for preoperative cardiohepatic evaluation.

PubMed

Reddy, Sahadev T; Thai, Ngoc L; Fakhri, Asghar A; Oliva, Jose; Tom, Kusum B; Dishart, Michael K; Doyle, Mark; Yamrozik, June A; Williams, Ronald B; Grant, Saundra B; Poydence, Jacqueline; Shah, Moneal; Singh, Anil; Nathan, Swami; Biederman, Robert W W

2013-11-15

Preoperative cardiovascular risk stratification in orthotopic liver transplantation candidates has proven challenging due to limitations of current noninvasive modalities. Additionally, the preoperative workup is logistically cumbersome and expensive given the need for separate cardiac, vascular, and abdominal imaging. We evaluated the feasibility of a "one-stop shop" in a magnetic resonance suite, performing assessment of cardiac structure, function, and viability, along with simultaneous evaluation of thoracoabdominal vasculature and liver anatomy. In this pilot study, patients underwent steady-state free precession sequences and stress cardiac magnetic resonance (CMR), thoracoabdominal magnetic resonance angiography, and abdominal magnetic resonance imaging (MRI) on a standard MRI scanner. Pharmacologic stress was performed using regadenoson, adenosine, or dobutamine. Viability was assessed using late gadolinium enhancement. Over 2 years, 51 of 77 liver transplant candidates (mean age, 56 years; 35% female; mean Model for End-stage Liver Disease score, 10.8; range, 6-40) underwent MRI. All referred patients completed standard dynamic CMR, 98% completed stress CMR, 82% completed late gadolinium enhancement for viability, 94% completed liver MRI, and 88% completed magnetic resonance angiography. The mean duration of the entire study was 72 min, and 45 patients were able to complete the entire examination. Among all 51 patients, 4 required follow-up coronary angiography (3 for evidence of ischemia on perfusion CMR and 1 for postoperative ischemia), and none had flow-limiting coronary disease. Nine proceeded to orthotopic liver transplantation (mean 74 days to transplantation after MRI). There were six ascertained mortalities in the nontransplant group and one death in the transplanted group. Explant pathology confirmed 100% detection/exclusion of hepatocellular carcinoma. No complications during CMR examination were encountered. In this proof-of-concept study, it

Combined magnetic resonance and optical imaging of head and neck tumor xenografts using Gadolinium-labelled phosphorescent polymeric nanomicelles

PubMed Central

2010-01-01

Background The overall objective of this study was to develop a nanoparticle formulation for dual modality imaging of head and neck cancer. Here, we report the synthesis and characterization of polymeric phospholipid-based nanomicelles encapsulating near-infrared (NIR) phosphorescent molecules of Pt(II)-tetraphenyltetranaphthoporphyrin [Pt(TPNP)] and surface functionalized with gadolinium [Pt(TPNP)-Gd] for combined magnetic resonance imaging (MRI) and NIR optical imaging applications. Methods Dynamic light scattering, electron microscopy, optical spectroscopy and MR relaxometric measurements were performed to characterize the optical and magnetic properties of nanoparticles in vitro. Subsequently, in vivo imaging experiments were carried out using nude mice bearing primary patient tumor-derived human head and neck squamous cell carcinoma xenografts. Results The nanomicelles were ~100 nm in size and stable in aqueous suspension. T1-weighted MRI and relaxation rate (R1 = 1/T1) measurements carried out at 4.7 T revealed enhancement in the tumor immediately post injection with nanomicelles, particularly in the tumor periphery which persisted up to 24 hours post administration. Maximum intensity projections (MIPs) generated from 3D T1-weighted images also demonstrated visible enhancement in contrast within the tumor, liver and blood vessels. NIR optical imaging performed (in vivo and ex vivo) following completion of MRI at the 24 h time point confirmed tumor localization of the nanoparticles. The large spectral separation between the Pt(TPNP) absorption (~700 nm) and phosphorescence emission (~900 nm) provided a dramatic decrease in the level of background, resulting in high contrast optical (NIR phosphorescence) imaging. Conclusions In conclusion, Pt(TPNP)-Gd nanomicelles exhibit a high degree of tumor-avidity and favorable imaging properties that allow for combined MR and optical imaging of head and neck tumors. Further investigation into the potential of Pt

Sensitivity and specificity of ultrasonography and low-field magnetic resonance imaging for diagnosing arthritis.

PubMed

Broll, Matthias; Albrecht, Katinka; Tarner, Ingo; Müller-Ladner, Ulf; Strunk, Johannes

2012-01-01

To evaluate the value of grey-scale ultrasonography (US) including power Doppler ultrasonography (PDUS) and low-field magnetic resonance imaging (MRI) for the diagnosis of arthritis in a diagnostic phase III study. Fifty consecutive patients with suspected arthritis were included in the study. Following a standardised protocol, US of the carpus and the metacarpophalangeal (MCP) joints of the dominant hand was performed. Subsequently, low-field MRI was done using standard sequences, with contrast agent (Gadolinium DTPA) administered to 29 patients. In 32 out of 50 patients a clinical diagnosis of arthritis was established. In grey-scale ultrasonography including PDUS, sensitivity and specificity were determined as 0.94 and 0.5, respectively, for synovitis (effusion and hypertrophy), 0.72 and 0.94, respectively, for Doppler signals, and 0.38 and 1.0, respectively, for bone erosions. In low-field MRI, sensitivity and specificity values were 0.77 and 0.75, respectively, for synovitis (when using contrast agent), 0.48 and 0.78, respectively, for bone marrow oedema, and 0.58 and 0.83, respectively, for bone erosion. Both grey-scale ultrasonography including PDUS and low-field MRI are suitable imaging methods for diagnosing arthritis at an early stage. However, PDUS displays a higher specificity and almost the same sensitivity as compared to contrast-enhanced MRI, while being a much simpler and less costly procedure.

Non-invasive magnetic resonance imaging follow-up of sono-sensitive liposome tumor delivery and controlled release after high-intensity focused ultrasound.

PubMed

Fowler, Robert Andrew; Fossheim, Sigrid L; Mestas, Jean-Louis; Ngo, Jacqueline; Canet-Soulas, Emmanuelle; Lafon, Cyril

2013-12-01

This work examines the use of lanthanide-based contrast agents and magnetic resonance imaging in monitoring liposomal behavior in vivo. Dysprosium (Dy) and gadolinium (Gd) chelates, Dy-diethylenetriaminepentaacetic acid bismethylamide (Dy-DTPA-BMA) and Gd-DTPA-BMA, were encapsulated in pegylated distearoylphosphatidylethanolamine-based (saturated) liposomes, and then intravenously injected into Copenhagen rats with subcutaneous Dunning AT2 xenografts. Liposome-encapsulated Dy chelate shortens transverse relaxation times (T(2) and T(2)*) of tissue; thus, liposomal accumulation in the tumor can be monitored by observing the decrease in T(2)* relaxation time over time. The tumor was treated at the time of maximum liposomal accumulation (48 h) with confocal, cavitating high-intensity focused ultrasound to induce liposomal payload release. Using liposome-encapsulated Gd chelate at high enough concentrations and saturated liposomal phospholipids induces an exchange-limited longitudinal (T(1)) relaxation when the liposomes are intact; when the liposomes are released, exchange limitation is relieved, thus allowing in vivo observation of payload release as a decrease in tumor T(1). Copyright © 2013 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Impact of fingolimod therapy on magnetic resonance imaging outcomes in patients with multiple sclerosis.

PubMed

Radue, Ernst-Wilhelm; O'Connor, Paul; Polman, Chris H; Hohlfeld, Reinhard; Calabresi, Peter; Selmaj, Krystof; Mueller-Lenke, Nicole; Agoropoulou, Catherine; Holdbrook, Frederick; de Vera, Ana; Zhang-Auberson, Lixin; Francis, Gordon; Burtin, Pascale; Kappos, Ludwig

2012-10-01

To assess the impact of fingolimod (FTY720) therapy on magnetic resonance imaging measures of inflammatory activity and tissue damage in patients participating in a 2-year, placebo-controlled, phase 3 study. Patients with active relapsing-remitting multiple sclerosis were randomized to receive fingolimod, 0.5 mg; fingolimod, 1.25 mg; or placebo for 2 years. Standardized magnetic resonance imaging scans were obtained at months 0, 6, 12, and 24 and centrally evaluated for number and volume of T1 gadolinium-enhancing, T2 hyperintense, and T1 hypointense lesions and for percentage of brain volume change. Findings were compared across subgroups by treatment and baseline characteristics. Worldwide, multicenter clinical trial. Patients were part of the fingolimod FTY720 Research Evaluating Effects of Daily Oral Therapy in Multiple Sclerosis (FREEDOMS) clinical trial for relapsing-remitting multiple sclerosis (N=1272). We measured the effect of therapy on acute inflammatory activity, burden of disease, and irreversible loss of brain volume. Fingolimod therapy resulted in rapid and sustained reductions in inflammatory lesion activity as assessed by gadolinium-enhancing and new/newly enlarged T2 lesions after 6, 12, and 24 months of therapy (P.001, all comparisons vs placebo). Changes in T2 hyperintense and T1 hypointense lesion volume also significantly favored fingolimod (P.05, all comparisons). Fingolimod, 0.5 mg (licensed dose), significantly reduced brain volume loss during months 0 to 6, 0 to 12, 12 to 24, and 0 to 24 (P.05, all comparisons) vs placebo, and subgroup analyses confirmed these effects over 2 years irrespective of the presence/absence of gadolinium-enhancing lesions, T2 lesion load, previous treatment status, or level of disability. These results, coupled with the significant reductions in relapse rates and disability progression reported previously, support the positive impact on long-term disease evolution. clinicaltrials.gov Identifier: NCT00289978

Contrast-Enhanced Magnetic Resonance Imaging of Gastric Emptying and Motility in Rats.

PubMed

Lu, Kun-Han; Cao, Jiayue; Oleson, Steven Thomas; Powley, Terry L; Liu, Zhongming

2017-11-01

The assessment of gastric emptying and motility in humans and animals typically requires radioactive imaging or invasive measurements. Here, we developed a robust strategy to image and characterize gastric emptying and motility in rats based on contrast-enhanced magnetic resonance imaging (MRI) and computer-assisted image processing. The animals were trained to naturally consume a gadolinium-labeled dietgel while bypassing any need for oral gavage. Following this test meal, the animals were scanned under low-dose anesthesia for high-resolution T1-weighted MRI in 7 Tesla, visualizing the time-varying distribution of the meal with greatly enhanced contrast against non-gastrointestinal (GI) tissues. Such contrast-enhanced images not only depicted the gastric anatomy, but also captured and quantified stomach emptying, intestinal filling, antral contraction, and intestinal absorption with fully automated image processing. Over four postingestion hours, the stomach emptied by 27%, largely attributed to the emptying of the forestomach rather than the corpus and the antrum, and most notable during the first 30 min. Stomach emptying was accompanied by intestinal filling for the first 2 h, whereas afterward intestinal absorption was observable as cumulative contrast enhancement in the renal medulla. The antral contraction was captured as a peristaltic wave propagating from the proximal to distal antrum. The frequency, velocity, and amplitude of the antral contraction were on average 6.34 ± 0.07 contractions per minute, 0.67 ± 0.01 mm/s, and 30.58 ± 1.03%, respectively. These results demonstrate an optimized MRI-based strategy to assess gastric emptying and motility in healthy rats, paving the way for using this technique to understand GI diseases, or test new therapeutics in rat models.The assessment of gastric emptying and motility in humans and animals typically requires radioactive imaging or invasive measurements. Here, we developed a robust strategy to image and

Magnetic Resonance Imaging of Liver Metastasis.

PubMed

Karaosmanoglu, Ali Devrim; Onur, Mehmet Ruhi; Ozmen, Mustafa Nasuh; Akata, Deniz; Karcaaltincaba, Musturay

2016-12-01

Liver magnetic resonance imaging (MRI) is becoming the gold standard in liver metastasis detection and treatment response assessment. The most sensitive magnetic resonance sequences are diffusion-weighted images and hepatobiliary phase images after Gd-EOB-DTPA. Peripheral ring enhancement, diffusion restriction, and hypointensity on hepatobiliary phase images are hallmarks of liver metastases. In patients with normal ultrasonography, computed tomography (CT), and positron emission tomography (PET)-CT findings and high clinical suspicion of metastasis, MRI should be performed for diagnosis of unseen metastasis. In melanoma, colon cancer, and neuroendocrine tumor metastases, MRI allows confident diagnosis of treatment-related changes in liver and enables differential diagnosis from primary liver tumors. Focal nodular hyperplasia-like nodules in patients who received platinum-based chemotherapy, hypersteatosis, and focal fat can mimic metastasis. In cancer patients with fatty liver, MRI should be preferred to CT. Although the first-line imaging for metastases is CT, MRI can be used as a problem-solving method. MRI may be used as the first-line method in patients who would undergo curative surgery or metastatectomy. Current limitation of MRI is low sensitivity for metastasis smaller than 3mm. MRI fingerprinting, glucoCEST MRI, and PET-MRI may allow simpler and more sensitive diagnosis of liver metastasis. Copyright © 2016 Elsevier Inc. All rights reserved.

In vitro cellular accumulation of gadolinium incorporated into chitosan nanoparticles designed for neutron-capture therapy of cancer.

PubMed

Shikata, Futoshi; Tokumitsu, Hiroyuki; Ichikawa, Hideki; Fukumori, Yoshinobu

2002-01-01

The accumulation of gadolinium loaded as gadopentetic acid (Gd-DTPA) in chitosan nanoparticles (Gd-nanoCPs), which were designed for gadolinium neutron-capture therapy (Gd-NCT) for cancer, was evaluated in vitro in cultured cells. Using L929 fibroblast cells, the Gd accumulation for 12 h at 37 degrees C was investigated at Gd concentrations lower than 40 ppm. The accumulation leveled above 20 ppm and reached 18.0+/-2.7 (mean+/-S.D.) microg Gd/10(6) cells at 40 ppm. Furthermore, the corresponding accumulations in B16F10 melanoma cells and SCC-VII squamous cell carcinoma, which were used in the previous Gd-NCT trials in vivo, were 27.1+/-2.9 and 59.8+/-9.8 microg Gd/10(6) cells, respectively, hence explaining the superior growth-suppression in the in vivo trials using SCC-VII cells. The accumulation of Gd-nanoCPs in these cells was 100-200 times higher in comparison to dimeglumine gadopentetate aqueous solution (Magnevist), a magnetic resonance imaging contrast agent. The endocytic uptake of Gd-nanoCPs, strongly holding Gd-DTPA, was suggested from transmission electron microscopy and comparative studies at 4 degrees C and with the solution system. These findings indicated that Gd-nanoCPs had a high affinity to the cells, probably contributing to the long retention of Gd in tumor tissue and leading to the significant suppression of tumor growth in the in vivo studies that were previously reported.

A novel paramagnetic substrate for detecting myeloperoxidase activity in vivo.

PubMed

Shazeeb, Mohammed S; Xie, Yang; Gupta, Suresh; Bogdanov, Alexei A

2012-01-01

Bis-phenylamides and bis-hydroxyindolamides of diethylenetriaminepentaacetic acid-gadolinium (DTPA(Gd)) are paramagnetic reducing substrates of peroxidases that enable molecular imaging of peroxidase activity in vivo. Specifically, gadolinium chelates of bis-5-hydroxytryptamide-DTPA (bis-5HT-DTPA(Gd)) have been used to image localized inflammation in animal models by detecting neutrophil-derived myeloperoxidase (MPO) activity at the inflammation site. However, in other preclinical disease models, bis-5HT-DTPA(Gd) presents technical challenges due to its limited solubility in vivo. Here we report a novel MPO-sensing probe obtained by replacing the reducing substrate serotonin (5-HT) with 5-hydroxytryptophan (HTrp). Characterization of the resulting probe (bis-HTrp-DTPA(Gd)) in vitro using nuclear magnetic resonance spectroscopy and enzyme kinetic analysis showed that bis-HTrp-DTPA(Gd) (1) improves solubility in water; (2) acts as a substrate for both horseradish peroxidase and MPO enzymes; (3) induces cross-linking of proteins in the presence of MPO; (4) produces oxidation products, which bind to plasma proteins; and (5) unlike bis-5HT-DTPA(Gd), does not follow first-order reaction kinetics. In vivo magnetic resonance imaging (MRI) in mice demonstrated that bis-HTrp-DTPA(Gd) was retained for up to 5 days in MPO-containing sites and cleared faster than bis-5HT-DTPA(Gd) from MPO-negative sites. Bis-HTrp-DTPA(Gd) should offer improvements for MRI of MPO-mediated inflammation in vivo, especially in high-field MRI, which requires a higher dose of contrast agent.

Gadolinium heteropoly complex K 17[Gd(P 2W 17O 61) 2] as a potential MRI contrast agent

NASA Astrophysics Data System (ADS)

Sun, Guoying; Feng, Jianghua; Wu, Huifeng; Pei, Fengkui; Fang, Ke; Lei, Hao

2004-10-01

Gadolinium heteropoly complex K17[Gd(P2W17O61)2] has been evaluated by in vitro and in vivo experiments as a potential contrast agent for magnetic resonance imaging (MRI). The thermal analysis and conductivity study indicate that this complex has good thermal stability and wide pH stability range. The T1 relaxivity is 7.59 mM-1 s-1 in aqueous solution and 7.97 mM-1 s-1 in 0.725 mmol l-1 bovine serum albumin (BSA) solution at 25 °C and 9.39 T, respectively. MR imaging of three male Sprague-Dawley rats showed remarkable enhancement in rat liver after intravenous injection, which persisted longer than with Gd-DTPA. The signal intensity increased by 57.1±16.9% during the whole imaging period at 0.082 mmol kg-1dose. Our preliminary in vitro and in vivo studies indicate that K17[Gd(P2W17O61)2] is a potential liver-specific MRI contrast agent.

Molecular nanomagnets as contrast agents for Magnetic Resonance Imaging

NASA Astrophysics Data System (ADS)

Rodríguez, Elisenda; Roig, Anna; Molins, Elies; Arús, Carles; Cabañas, Miquel; Quintero, María Rosa; Cerdán, Sebastián; Sanfeliu, Coral

2003-03-01

Magnetic resonance imaging (MRI) is a non-invasive technique used in medicine to produce high quality images of human body slices. In order to enhance the contrast between different organs or to reveal altered portions of them such necrosis or tumors, the administration of a contrast agent is highly convenient. Currently Gd-DTPA, a paramagnetic complex, is the most widely administered compound. In this context, we have assayed molecular nanomagnets as MRI contrast agents. The complex [(tacn)_6Fe_8(μ_3-O)_2(μ_2-OH)_12]Br_8·9H_2O^1(Fe8 in brief) has been evaluated and shorter relaxation times, T1 and T_2, have been obtained for Fe8 than those obtained for the commercial Gd-DTPA. No toxic effects have been observed at concentrations up to 1 mM of Fe8 in cultured cells. Phantom studies with T_1-weighted MRI at 9.4 Tesla suggest that Fe8 can have potentiality as T_1-contrast agent. ^1Wieghardt K Angew Chem Intl Ed Engl 23 1 (1984) 77

Pathophysiology of gadolinium-associated systemic fibrosis

PubMed Central

Drel, Viktor; Gorin, Yves

2016-01-01

Systemic fibrosis from gadolinium-based magnetic resonance imaging contrast is a scourge for the afflicted. Although gadolinium-associated systemic fibrosis is a rare condition, the threat of litigation has vastly altered clinical practice. Most theories concerning the etiology of the fibrosis are grounded in case reports rather than experiment. This has led to the widely accepted conjecture that the relative affinity of certain contrast agents for the gadolinium ion inversely correlates with the risk of succumbing to the disease. How gadolinium-containing contrast agents trigger widespread and site-specific systemic fibrosis and how chronicity is maintained are largely unknown. This review highlights experimentally-derived information from our laboratory and others that pertain to our understanding of the pathophysiology of gadolinium-associated systemic fibrosis. PMID:27147669

Evaluation of liver function using gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid enhanced magnetic resonance imaging based on a three-dimensional volumetric analysis system.

PubMed

Kudo, Masashi; Gotohda, Naoto; Sugimoto, Motokazu; Kobayashi, Tatsushi; Kojima, Motohiro; Takahashi, Shinichiro; Konishi, Masaru; Hayashi, Ryuichi

2018-06-02

Magnetic resonance imaging with gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (EOB-MRI) is a diagnostic modality for liver tumors. Three-dimensional (3D) volumetric analysis systems using EOB-MRI data are used to simulate liver anatomy for surgery. This study was conducted to investigate clinical utility of a 3D volumetric analysis system on EOB-MRI to evaluate liver function. Between August 2014 and December 2015, 181 patients underwent laboratory and radiological exams as standardized preoperative evaluation for liver surgery. The liver-spleen contrast-enhanced ratio (LSR) was measured by a semi-automated 3D volumetric analysis system on EOB-MRI. First, the inter-evaluator variability of the calculated LSR was evaluated. Additionally, a subset of liver surgical specimens was evaluated histologically by using immunohistochemical staining. Finally, the correlations between the LSR and grading systems of liver function, laboratory data, or histological findings were analyzed. The inter-evaluator correlation coefficient of the measured LSR was 0.986. The mean LSR was significantly correlated with the Child-Pugh score (p = 0.014) and the ALBI score (p < 0.001). Significant correlations were also observed between the LSR and indocyanine green retention rate at 15 min (r = - 0.601, p < 0.001), between the LSR and liver fibrosis stage (r = - 0.556, p < 0.001), and between the LSR and liver steatosis grade (r = - 0.396, p < 0.001). The LSR calculated by a 3D volumetric analysis system on EOB-MRI was highly reproducible and was shown to be correlated with liver function parameters and liver histology. These data suggest that this imaging modality can be a reliable tool to evaluate liver function.

Does stress perfusion imaging improve the diagnostic accuracy of late gadolinium enhanced cardiac magnetic resonance for establishing the etiology of heart failure?

PubMed

Gulsin, Gaurav S; Shetye, Abishek; Khoo, Jeffrey; Swarbrick, Daniel J; Levelt, Eylem; Lai, Florence Y; Squire, Iain B; Arnold, Jayanth R; McCann, Gerry P

2017-04-08

Late gadolinium enhanced cardiovascular magnetic resonance (LGE-CMR) has excellent specificity, sensitivity and diagnostic accuracy for differentiating between ischemic cardiomyopathy (ICM) and non-ischemic dilated cardiomyopathy (NICM). CMR first-pass myocardial perfusion imaging (perfusion-CMR) may also play role in distinguishing heart failure of ischemic and non-ischemic origins, although the utility of additional of stress perfusion imaging in such patients is unclear. The aim of this retrospective study was to assess whether the addition of adenosine stress perfusion imaging to LGE-CMR is of incremental value for differentiating ICM and NICM in patients with severe left ventricular systolic dysfunction (LVSD) of uncertain etiology. We retrospectively identified 100 consecutive adult patients (median age 69 years (IQR 59-73)) with severe LVSD (mean LV EF 26.6 ± 7.0%) referred for perfusion-CMR to establish the underlying etiology of heart failure. The cause of heart failure was first determined on examination of CMR cine and LGE images in isolation. Subsequent examination of complete adenosine stress perfusion-CMR studies (cine, LGE and perfusion images) was performed to identify whether this altered the initial diagnosis. On LGE-CMR, 38 patients were diagnosed with ICM, 46 with NICM and 16 with dual pathology. With perfusion-CMR, there were 39 ICM, 44 NICM and 17 dual pathology diagnoses. There was excellent agreement in diagnoses between LGE-CMR and perfusion-CMR (κ 0.968, p<0.001). The addition of adenosine stress perfusion images to LGE-CMR altered the diagnosis in only two of the 100 patients. The addition of adenosine stress perfusion-CMR to cine and LGE-CMR provides minimal incremental diagnostic yield for determining the etiology of heart failure in patients with severe LVSD.

T2* mapping and delayed gadolinium-enhanced magnetic resonance imaging in cartilage (dGEMRIC) of humeral articular cartilage--a histologically controlled study.

PubMed

Bittersohl, Bernd; Kircher, Jörn; Miese, Falk R; Dekkers, Christin; Habermeyer, Peter; Fröbel, Julia; Antoch, Gerald; Krauspe, Rüdiger; Zilkens, Christoph

2015-10-01

Cartilage biochemical imaging modalities that include the magnetic resonance imaging (MRI) techniques of T2* mapping (sensitive to water content and collagen fiber network) and delayed gadolinium-enhanced MRI of cartilage (dGEMRIC, sensitive to the glycosaminoglycan content) can be effective instruments for early diagnosis and reliable follow-up of cartilage damage. The purpose of this study was to provide T2* mapping and dGEMRIC values in various histologic grades of cartilage degeneration in humeral articular cartilage. A histologically controlled in vitro study was conducted that included human humeral head cartilage specimens with various histologic grades of cartilage degeneration. High-resolution, 3-dimensional (3D) T2* mapping and dGEMRIC were performed that enabled the correlation of MRI and histology data. Cartilage degeneration was graded according to the Mankin score, which evaluates surface morphology, cellularity, toluidine blue staining, and tidemark integrity. SPSS software was used for statistical analyses. Both MRI mapping values decreased significantly (P < .001) with increasing cartilage degeneration. Spearman rank analysis revealed a significant correlation (correlation coefficients ranging from -0.315 to 0.784; P < .001) between the various histologic parameters and the T2* and T1Gd mapping values. This study demonstrates the feasibility of 3D T2* and dGEMRIC to identify various histologic grades of cartilage damage of humeral articular cartilage. With regard to the advantages of these mapping techniques with high image resolution and the ability to accomplish a 3D biochemically sensitive imaging, we consider that these imaging techniques can make a positive contribution to the currently evolving science and practice of cartilage biochemical imaging. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Gadolinium Endohedral Metallofullerene-Based MRI Contrast Agents

NASA Astrophysics Data System (ADS)

Bolskar, Robert D.

With the ability to encapsulate and carry the highly paramagnetic Gd3+ ion, gadolinium endohedral metallofullerenes or "gadofullerenes" are being explored as alternatives to the chelate complexes that are currently used for contrast-enhanced magnetic resonance imaging (MRI). Reviewed here are the various water-soluble derivatives of the gadofullerenes Gd@C82, Gd@C60, and Gd3N@C80 that have been investigated as MRI contrast agents. The water proton r1 relaxivities of gadofullerenes can be more than an order of magnitude higher than those of clinically used chelate agents. Gadofullerene relaxivity mechanisms have been studied, and multiple factors are found to contribute to their high relaxivities. In vitro and in vivoT1-weighted MRI tests of gadofullerene derivatives have shown their utility as bright image-enhancing agents. The gadofullerene MRI contrast agents are a promising new and unique style of gadolinium carrier for advanced imaging applications, including cellular and molecular imaging.

Dual-mode T1 and T2 magnetic resonance imaging contrast agent based on ultrasmall mixed gadolinium-dysprosium oxide nanoparticles: synthesis, characterization, and in vivo application

NASA Astrophysics Data System (ADS)

Tegafaw, Tirusew; Xu, Wenlong; Wasi Ahmad, Md; Baeck, Jong Su; Chang, Yongmin; Bae, Ji Eun; Chae, Kwon Seok; Kim, Tae Jeong; Lee, Gang Ho

2015-09-01

A new type of dual-mode T1 and T2 magnetic resonance imaging (MRI) contrast agent based on mixed lanthanide oxide nanoparticles was synthesized. Gd3+ (8S7/2) plays an important role in T1 MRI contrast agents because of its large electron spin magnetic moment resulting from its seven unpaired 4f-electrons, and Dy3+ (6H15/2) has the potential to be used in T2 MRI contrast agents because of its very large total electron magnetic moment: among lanthanide oxide nanoparticles, Dy2O3 nanoparticles have the largest magnetic moments at room temperature. Using these properties of Gd3+ and Dy3+ and their oxide nanoparticles, ultrasmall mixed gadolinium-dysprosium oxide (GDO) nanoparticles were synthesized and their potential to act as a dual-mode T1 and T2 MRI contrast agent was investigated in vitro and in vivo. The D-glucuronic acid coated GDO nanoparticles (davg = 1.0 nm) showed large r1 and r2 values (r2/r1 ≈ 6.6) and as a result clear dose-dependent contrast enhancements in R1 and R2 map images. Finally, the dual-mode imaging capability of the nanoparticles was confirmed by obtaining in vivo T1 and T2 MR images.

Diagnosis of endolymphatic hydrops by means of 3T magnetic resonance imaging after intratympanic administration of gadolinium.

PubMed

Tuñón Gómez, M; Lobo Duro, D R; Brea Álvarez, B; García-Berrocal, J R

To detect and graduate endolymphatic hydrops or endolymphatic space dilations in patients with suspected Meniere's disease or immune-mediated inner ear disease by magnetic resonance imaging. A prospective study was performed including all the patients with clinical suspicion of Meniere's disease or immune-mediated inner ear disease treated at the Otolaryngology department during a one year period. In all cases, magnetic resonance imaging (MRI) was performed in a 3T scanner. IR sequence was performed after 24 to 28h prior intratimpanic injection of gadolinium on both ears. Two neurorradiologist graduated endolymphatic space volume as agreed on normal, moderate and significant in the obtained images. The presence of hydrops was documented by MRI in six patients with definite or probable Meniere's disease. In two of the four cases without vertigo hydrops was not demonstrated. In the other two cases with a high clinical suspicion of immune-mediated disease but with negative autoimmune tests hydrops was proved. There was only disagreement on cochlear hydrops presence on two patients. The detection of endolymphatic hydrops in patients with definite or probable Meniere's disease served to confirm the final diagnosis. Moreover, hydrops was detected in patients with suspected immune-mediated inner ear disease, which could have an impact on the diagnosis and treatment of these patients. Therefore, we suggest that this test could be included for the diagnosis of these inner ear diseases. Copyright © 2016 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

Gadolinium Deposition in Human Brain Tissues after Contrast-enhanced MR Imaging in Adult Patients without Intracranial Abnormalities.

PubMed

McDonald, Robert J; McDonald, Jennifer S; Kallmes, David F; Jentoft, Mark E; Paolini, Michael A; Murray, David L; Williamson, Eric E; Eckel, Laurence J

2017-11-01

Purpose To determine whether gadolinium deposits in neural tissues of patients with intracranial abnormalities following intravenous gadolinium-based contrast agent (GBCA) exposure might be related to blood-brain barrier integrity by studying adult patients with normal brain pathologic characteristics. Materials and Methods After obtaining antemortem consent and institutional review board approval, the authors compared postmortem neuronal tissue samples from five patients who had undergone four to 18 gadolinium-enhanced magnetic resonance (MR) examinations between 2005 and 2014 (contrast group) with samples from 10 gadolinium-naive patients who had undergone at least one MR examination during their lifetime (control group). All patients in the contrast group had received gadodiamide. Neuronal tissues from the dentate nuclei, pons, globus pallidus, and thalamus were harvested and analyzed with inductively coupled plasma mass spectrometry (ICP-MS), transmission electron microscopy with energy-dispersive x-ray spectroscopy, and light microscopy to quantify, localize, and assess the effects of gadolinium deposition. Results Tissues from the four neuroanatomic regions of gadodiamide-exposed patients contained 0.1-19.4 μg of gadolinium per gram of tissue in a statistically significant dose-dependent relationship (globus pallidus: ρ = 0.90, P = .04). In contradistinction, patients in the control group had undetectable levels of gadolinium with ICP-MS. All patients had normal brain pathologic characteristics at autopsy. Three patients in the contrast group had borderline renal function (estimated glomerular filtration rate <45 mL/min/1.73 m 2 ) and hepatobiliary dysfunction at MR examination. Gadolinium deposition in the contrast group was localized to the capillary endothelium and neuronal interstitium and, in two cases, within the nucleus of the cell. Conclusion Gadolinium deposition in neural tissues after GBCA administration occurs in the absence of intracranial

Gated-SPECT myocardial perfusion imaging as a complementary technique to magnetic resonance imaging in chronic myocardial infarction patients.

PubMed

Cuberas-Borrós, Gemma; Pineda, Victor; Aguadé-Bruix, Santiago; Romero-Farina, Guillermo; Pizzi, M Nazarena; de León, Gustavo; Castell-Conesa, Joan; García-Dorado, David; Candell-Riera, Jaume

2013-09-01

The aim of this study was to compare magnetic resonance and gated-SPECT myocardial perfusion imaging in patients with chronic myocardial infarction. Magnetic resonance imaging and gated-SPECT were performed in 104 patients (mean age, 61 [12] years; 87.5% male) with a previous infarction. Left ventricular volumes and ejection fraction and classic late gadolinium enhancement viability criteria (<75% transmurality) were correlated with those of gated-SPECT (uptake >50%) in the 17 segments of the left ventricle. Motion, thickening, and ischemia on SPECT were analyzed in segments showing nonviable tissue or equivocal enhancement features (50%-75% transmurality). A good correlation was observed between the 2 techniques for volumes, ejection fraction (P<.05), and estimated necrotic mass (P<.01). In total, 82 of 264 segments (31%) with >75% enhancement had >50% single SPECT uptake. Of the 106 equivocal segments on magnetic resonance imaging, 68 (64%) had >50% uptake, 41 (38.7%) had normal motion, 46 (43.4%) had normal thickening, and 17 (16%) had ischemic criteria on SPECT. A third of nonviable segments on magnetic resonance imaging showed >50% uptake on SPECT. Gated-SPECT can be useful in the analysis of motion, thickening, and ischemic criteria in segments with questionable viability on magnetic resonance imaging. Copyright © 2013 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

Structural and magnetic phase transitions in gadolinium under high pressures and low temperatures

DOE PAGES

Samudrala, Gopi K.; Tsoi, Georgiy M.; Weir, Samuel T.; ...

2014-11-07

High pressure structural transition studies have been carried out on rare earth metal gadolinium in a diamond anvil cell at room temperature to 169 GPa. Gadolinium has been compressed to 38% of its initial volume at this pressure. With increasing pressure, a crystal structure sequence of hcp → Smtype→ dhcp → fcc → dfcc → monoclinic has been observed in our studies on gadolinium. The measured equation of state of gadolinium is presented to 169 GPa at ambient temperature. Magnetic ordering temperature of gadolinium has been studied using designer diamond anvils to a pressure of 25 GP and a temperaturemore » of 10 K. The magnetic ordering temperature has been determined from the four-point electrical resistivity measurements carried out on gadolinium. Furthermore, our experiments show that the magnetic transition temperature decreases with increasing pressure to 19 GPa and then increases when gadolinium is subjected to higher pressures.« less

Structural and magnetic phase transitions in gadolinium under high pressures and low temperatures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Samudrala, Gopi K.; Tsoi, Georgiy M.; Weir, Samuel T.

High pressure structural transition studies have been carried out on rare earth metal gadolinium in a diamond anvil cell at room temperature to 169 GPa. Gadolinium has been compressed to 38% of its initial volume at this pressure. With increasing pressure, a crystal structure sequence of hcp → Smtype→ dhcp → fcc → dfcc → monoclinic has been observed in our studies on gadolinium. The measured equation of state of gadolinium is presented to 169 GPa at ambient temperature. Magnetic ordering temperature of gadolinium has been studied using designer diamond anvils to a pressure of 25 GP and a temperaturemore » of 10 K. The magnetic ordering temperature has been determined from the four-point electrical resistivity measurements carried out on gadolinium. Furthermore, our experiments show that the magnetic transition temperature decreases with increasing pressure to 19 GPa and then increases when gadolinium is subjected to higher pressures.« less

Structural and magnetic phase transitions in gadolinium under high pressures and low temperatures

NASA Astrophysics Data System (ADS)

Samudrala, Gopi K.; Tsoi, Georgiy M.; Weir, Samuel T.; Vohra, Yogesh K.

2014-10-01

High pressure structural transition studies have been carried out on rare earth metal gadolinium in a diamond anvil cell at room temperature to 169 GPa. Gadolinium has been compressed to 38% of its initial volume at this pressure. With increasing pressure, a crystal structure sequence of hcp → Sm-type → dhcp → fcc → dfcc → monoclinic has been observed in our studies on gadolinium. The measured equation of state of gadolinium is presented to 169 GPa at ambient temperature. Magnetic ordering temperature of gadolinium has been studied using designer diamond anvils to a pressure of 25 GPa and a temperature of 10 K. The magnetic ordering temperature has been determined from the four-point electrical resistivity measurements carried out on gadolinium. Our experiments show that the magnetic transition temperature decreases with increasing pressure to 19 GPa and then increases when gadolinium is subjected to higher pressures.

Comparison of MRI properties between derivatized DTPA and DOTA gadolinium-dendrimer conjugates.

PubMed

Nwe, K; Bernardo, M; Regino, C A S; Williams, M; Brechbiel, M W

2010-08-15

In this report we directly compare the in vivo and in vitro MRI properties of gadolinium-dendrimer conjugates of derivatized acyclic diethylenetriamine-N,N',N',N'',N''-pentaacetic acid (1B4M-DTPA) and macrocyclic 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (C-DOTA). The metal-ligand chelates were pre-formed in alcohol prior to conjugation to the generation 4 PAMAM dendrimer (G4D), and the dendrimer-based agents were purified by Sephadex(R) G-25 column. The analysis and SE-HPLC data indicated chelate to dendrimer ratios of 30:1 and 28:1, respectively. Molar relaxivity measured at pH 7.4, 22 degrees C, and 3T are comparable (29.5 vs 26.9 mM(-1)s(-1)), and both conjugates are equally viable as MRI contrast agents based on the images obtained. The macrocyclic agent however exhibits a faster rate of clearance in vivo (t(1/2)=16 vs 29 min). Our conclusion is that the macrocyclic-based agent is the more suitable agent for in vivo use for these reasons combined with kinetic inertness associated with the Gd(III) DOTA complex stability properties. Published by Elsevier Ltd.

Magnetic resonance imaging in the pre-operative evaluation of obstructive epiphora: true-FISP and VIBE vs gadolinium.

PubMed

Somma, Francesco; d'Agostino, Vincenzo; Tortora, Fabio; Serra, Nicola; Sorrentino, Gerardo; Piscitelli, Valeria; Somma, Andrea; Gamerra, Mario

2017-02-01

To assess unenhanced magnetic resonance imaging (MRI) in the preoperative evaluation of obstructive epiphora in patients undergoing dacryocystorhinostomy (DCR) and in particular, to evaluate the efficacy of this technique in the detection of the exact level of obstruction occurring in the naso-lachrymal duct (NLD). The correct identification and characterization of the NLD and its obstructions lead to a more effective surgery, preventing recurrent dacryocystitis after the surgical treatment. From January 2009 to December 2014, 127 obstructive epiphoras were diagnosed and treated in 127 patients (35 M, 92 F; mean age 60.7 ± 7.48 years, range 42-75 years) with endoscopic DCR, in a IRB-approved protocol. To precisely define the morphology of the NLD and the site of obstruction, some of these patients (67/127) underwent unenhanced 1.5-T MR with TrueFISP and VIBE sequences, while the remaining (60/127) underwent Gadolinium-enhanced 1.5-T MR. Afterwards, surgery checked the real site of obstruction in both groups of patients (enhanced and unenhanced MR), with surgical outcomes matched with previous MR reports. In all cases, unenhanced MRI was able to detect the exact site of obstruction along the NLD, allowing a correct planning of surgical endoscopic procedures. On the contrary, enhanced MRI wrongly diagnosed six patients with proximal stenosis (6/60, 10.0%) as intermediate NLD obstruction. Unenhanced MRI was found to be more accurate than enhanced MRI with a statistical significant difference (p value = 0.0256) and obviously cheaper and easier to perform. All imaging reports were verified with surgery. The correct identification of the level of obstruction allowed successful surgery in around 73% (93/127) of patients, who had no recurrence during 6-month follow-up. In patients with epiphora, unenhanced MR showed to be highly reliable and even more effective than enhanced MR in the preoperative characterization of NLD stenosis, with no need of performing complex

Cardiovascular Magnetic Resonance Imaging of Myocardial Infarction, Viability, and Cardiomyopathies

PubMed Central

West, Amy M.; Kramer, Christopher M.

2010-01-01

Cardiovascular magnetic resonance provides the opportunity for a truly comprehensive evaluation of patients with a history of MI, with regards to characterizing the extent of disease, impact on LV function and degree of viable myocardium. The use of contrast-enhanced CMR for first-pass perfusion and late gadolinium enhancement is a powerful technique for delineating areas of myocardial ischemia and infarction. Using a combination of T2-weighted and contrast-enhanced CMR images, information about the acuity of an infarct can be obtained. There is an extensive amount of literature using contrast-enhanced CMR to predict myocardial functional recovery with revascularization in patients with ischemic cardiomyopathies. In addition, CMR imaging in patients with cardiomyopathies can distinguish between ischemic and non-ischemic etiologies, with the ability to further characterize the underlying pathology for non-ischemic cardiomyopathies. PMID:20197150

A novel contrast agent with rare earth-doped up-conversion luminescence and Gd-DTPA magnetic resonance properties

NASA Astrophysics Data System (ADS)

Lu, Qing; Wei, Daixu; Cheng, Jiejun; Xu, Jianrong; Zhu, Jun

2012-08-01

The magnetic-luminescent multifunctional nanoparticles based on Gd-DTPA and NaYF4:Yb, Er were successfully synthesized by the conjugation of activated DTPA and silica-coated/surface-aminolated NaYF4:Yb, Er nanoparticles through EDC/NHS coupling chemistry. The as-prepared products were characterized by powder X-ray diffraction, transmission electron microscopy, dynamic light scattering, energy dispersive X-ray analysis, and fourier transform infrared spectrometry. The room-temperature upconversion luminescent spectra and T1-weighted maps of the obtained nanoparticles were carried out by 980 nm NIR light excitation and a 3T MR imaging scanner, respectively. The results indicated that the as-synthesized multifunctional nanoparticles with small size, highly solubility in water, and both high MR relaxivities and upconversion luminescence may have potential usage for MR imaging in future.

[Imaging and quantitative measurement of brain extracellular space using MRI Gd-DTPA tracer method].

PubMed

He, Qing-yuan; Han, Hong-bin; Xu, Fang-jing-wei; Yan, Jun-hao; Zeng, Jin-jin; Li, Xiao-gang; Fu, Yu; Peng, Yun; Chen, He; Hou, Chao; Xu, Xiao-juan

2010-04-18

To observe the diffusion of Gd-DTPA in brain extracellular space (ECS) by magnetic resonance imaging(MRI) and investigate the feasibility of ECS measurement by using MRI tracer method in vivo. 2 microL Gd-DTPA was introduced into ECS by caudate nucleus according to stereotaxic atlas in 8 Sprague Dawley(SD) rats (male, 280-320 g). The MRI scans were performed at 1 h, 3 h, 6 h, 9 h and 12 h respectively after administration. MRI appearances of Gd-DTPA diffusion and distribution was observed and compared. The MRI signal enhancement was measured at each time point. The neuroethology assessment was performed after MRI scanning at 12 h. The injection was accurate at the center of the caudate nucleus in 6 rats, while, at the capsula externa in other 2 rats. Gd-DTPA diffused isotropically after it was introduced into caudate nucleus, which spread into lateral cortex at 3 h. The MRI signal enhancement distributed mainly in the middle cerebral artery territory. A significant difference was found between the signal enhancement ratio at 1 h and that at 3 h in the original point of caudate nucleus (t=95.63, P<0.01), and the signal enhancement attenuated following the exponential power function y=1.7886x(-0.1776) (R2=0.94). In 2 rats with the injection point at capsula externa, Gd-DTPA diffused anisotropically along the fiber track of white matter during 1 h to 3 h, and spread into the lateral cortex at 6 h. The diffusion and clearance of Gd-DTPA in brain ECS could be monitored and measured quantitatively in vivo by MRI tracer method.

Utility of late gadolinium enhancement in pediatric cardiac MRI.

PubMed

Etesami, Maryam; Gilkeson, Robert C; Rajiah, Prabhakar

2016-07-01

Late gadolinium enhancement (LGE) cardiac magnetic resonance (MR) imaging sequence is increasingly used in the evaluation of pediatric cardiovascular disorders, and although LGE might be a normal feature at the sites of previous surgeries, it is pathologically seen as a result of extracellular space expansion, either from acute cell damage or chronic scarring or fibrosis. LGE is broadly divided into ischemic and non-ischemic patterns. LGE caused by myocardial infarction occurs in a vascular distribution and always involves the subendocardial portion, progressively involving the outer regions in a waveform pattern. Non-ischemic cardiomyopathies can have a mid-myocardial (either linear or patchy), subepicardial or diffuse subendocardial distribution. Idiopathic dilated cardiomyopathy can have a linear mid-myocardial pattern, while hypertrophic cardiomyopathy can have fine, patchy enhancement in hypertrophied and non-hypertrophied segments as well as right ventricular insertion points. Myocarditis and sarcoidosis have a mid-myocardial or subepicardial pattern of LGE. Fabry disease typically affects the basal inferolateral segment while Danon disease typically spares the septum. Pericarditis is characterized by diffuse or focal pericardial thickening and enhancement. Thrombus, the most common non-neoplastic cardiac mass, is characterized by absence of enhancement in all sequences, while neoplastic masses show at least some contrast enhancement, depending on the pathology. Regardless of the etiology, presence of LGE is associated with a poor prognosis. In this review, we describe the technical modifications required for performing LGE cardiac MR sequence in children, review and illustrate the patterns of LGE in children, and discuss their clinical significance.

Idiopathic and diabetic skeletal muscle necrosis: evaluation by magnetic resonance imaging.

PubMed

Kattapuram, Taj M; Suri, Rajeev; Rosol, Michael S; Rosenberg, Andrew E; Kattapuram, Susan V

2005-04-01

Idiopathic and diabetic-associated muscle necrosis are similar, uncommon clinical entities requiring conservative management and minimal intervention to avoid complications and prolonged hospitalization. An early noninvasive diagnosis is therefore essential. We evaluated the magnetic resonance imaging (MRI) characteristics of muscle necrosis in 14 patients, in eight of whom the diagnoses were confirmed histologically. Two experienced musculoskeletal radiologists performed retrospective evaluations of the MRI studies of 14 patients with the diagnoses of skeletal muscle infarction. In 10 cases gadolinium-enhanced (T1-weighted fat-suppressed) sequences were available along with T1-weighted, T2-weighted images and STIR sequences, while in four cases contrast-enhanced images were not available. Eight patients had underlying diabetes and in six patients the cause of the myonecrosis was considered idiopathic. T1-weighted images demonstrated isointense swelling of the involved muscle, with mildly displaced fascial planes. There was effacement of the fat signal intensity within the muscle. Fat-suppressed T2-weighted images showed diffuse heterogeneous high signal intensity in the muscles suggestive of edema. Perifascial fluid collection was seen in eight cases. Subcutaneous edema was present in seven patients. Following intravenous gadolinium administration, MRI demonstrated a focal area of heterogeneously enhancing mass with peripheral enhancement. Within this focal lesion, linear dark areas were seen with serpentine enhancing streaks separating them in eight cases. In two cases, a central relatively nonenhancing mass with irregular margins and peripheral enhancement was noted. The peripheral enhancement involved a significant part of the muscle. No focal fluid collection was noted. We believe that the constellation of imaging findings on T1- and T2-weighted images and post-gadolinium sequences is highly suggestive of muscle necrosis. We consider certain specific findings

Use of cardiovascular magnetic resonance in the evaluation of a giant right atrial appendage aneurysm: a case report and review of the literature.

PubMed

Sivakumaran, Lojan; Sayegh, Karl; Mehanna, Emile; Sanchez, Frank W; Fields, Jonathan; Cury, Ricardo

2017-12-04

Right atrial appendage aneurysms are rare entities that may have significant clinical consequences. When co-existing with atrial fibrillation, patients are at risk of developing pulmonary or paradoxical systemic emboli. An elderly patient presented to medical attention with symptoms of acute diverticulitis. On abdominal computed tomography, a massively enlarged right atrial appendage aneurysm was discovered incidentally. The aneurysm caused marked compression of the right ventricle and contained an area of hypoenhancement concerning for an intraluminal thrombus. Gadolinium-enhanced cardiovascular magnetic resonance was performed and first-pass perfusion images demonstrated that the area of hypoenhancement was in fact poorly mixing blood. The patient was therefore managed medically. Right atrial appendage aneurysms are infrequently encountered cardiac abnormalities. In the literature, surgery has been offered to patients who are young, symptomatic, or have evidence of thrombotic disease, although whether this practice pattern is associated with superior clinical outcomes is unclear. In the present case, gadolinium-enhanced cardiovascular magnetic resonance imaging was used to exclude the presence of intraluminal thrombus in an elderly patient, which helped orient the patient's treating team towards medical-rather than surgical-therapy.

Magnetic Resonance Imaging of a Liver Hydatid Cyst Invading the Portal Vein and Causing Portal Cavernomatosis.

PubMed

Herek, Duygu; Sungurtekin, Ugur

2015-01-01

Hepatic hydatid cysts rarely invade portal veins causing portal cavernomatosis as a secondary complication. We report the case of a patient with direct invasion of the right portal vein by hydatid cysts causing portal cavernomatosis diagnosed via magnetic resonance imaging (MRI). The presented case highlights the useful application of MRI with T2-weighted images and gadolinium-enhanced T1-weighted images in the diagnosis of hepatic hydatid lesions presenting with a rare complication of portal cavernomatosis.

Effect of Cu2+ substitution on the structural, magnetic and electrical properties of gadolinium orthoferrite

NASA Astrophysics Data System (ADS)

Sai Vandana, C.; Hemalatha Rudramadevi, B.

2018-04-01

The pure and copper (Cu) substituted Gadolinium orthoferrites, GdFeO3, GdCu0.1Fe0.9O3, GdCu0.2Fe0.8O3 and GdCu0.3Fe0.7O3 were synthesized by conventional solid state method. The structural, morphological, dielectric, magnetic and impedance properties of Cu substituted Gadolinium orthoferrites have been investigated. The crystallographic phase as well as the substitution of Cu2+ ions in the lattice of GdFeO3 is confirmed from the x-ray diffraction patterns. The Fourier transform infrared spectra exhibit two prominent fundamental absorption peaks at ∼417 cm‑1 and 545 cm‑1. These bands are related to inherent stretching vibrations of metals at octahedral and tetrahedral sites respectively. The coercivity (Hc) and saturation magnetization (Ms) of the synthesized samples at different temperatures were determined from the hysteresis plots. Higher coercive values, 598 Oe and 600 Oe were achieved in GdCu0.1Fe0.9O3 ferrites compared to 527 Oe and 360 Oe in pure GdFeO3 at room temperature (300 K) and low temperature (20 k) respectively. Dielectric dispersion has been observed for gadolinium ferrite samples with Maxwell–Wagner type interfacial polarization. The decrease of dielectric constant and dielectric loss tangent with an increase in frequency was observed. The conduction due to charge hopping between localized states was confirmed from AC conductivity measurements. The composition dependent cationic distributions estimated from XRD, magnetic and electrical studies are in good agreement with each other. The achieved results indicate that the substitution of Cu in gadolinium orthoferrite strongly influences the crystal structure, magnetic and electrical properties thereby making them suitable as multiple state memory devices, transducers, electronic field controlled ferromagnetic resonance devices and spintronic devices.

Fast magnetic resonance fingerprinting for dynamic contrast-enhanced studies in mice.

PubMed

Gu, Yuning; Wang, Charlie Y; Anderson, Christian E; Liu, Yuchi; Hu, He; Johansen, Mette L; Ma, Dan; Jiang, Yun; Ramos-Estebanez, Ciro; Brady-Kalnay, Susann; Griswold, Mark A; Flask, Chris A; Yu, Xin

2018-05-09

The goal of this study was to develop a fast MR fingerprinting (MRF) method for simultaneous T 1 and T 2 mapping in DCE-MRI studies in mice. The MRF sequences based on balanced SSFP and fast imaging with steady-state precession were implemented and evaluated on a 7T preclinical scanner. The readout used a zeroth-moment-compensated variable-density spiral trajectory that fully sampled the entire k-space and the inner 10 × 10 k-space with 48 and 4 interleaves, respectively. In vitro and in vivo studies of mouse brain were performed to evaluate the accuracy of MRF measurements with both fully sampled and undersampled data. The application of MRF to dynamic T 1 and T 2 mapping in DCE-MRI studies were demonstrated in a mouse model of heterotopic glioblastoma using gadolinium-based and dysprosium-based contrast agents. The T 1 and T 2 measurements in phantom showed strong agreement between the MRF and the conventional methods. The MRF with spiral encoding allowed up to 8-fold undersampling without loss of measurement accuracy. This enabled simultaneous T 1 and T 2 mapping with 2-minute temporal resolution in DCE-MRI studies. Magnetic resonance fingerprinting provides the opportunity for dynamic quantification of contrast agent distribution in preclinical tumor models on high-field MRI scanners. © 2018 International Society for Magnetic Resonance in Medicine.

Comparison of MRI properties between derivatized DTPA and DOTA gadolinium-dendrimer conjugates

PubMed Central

Nwe, K.; Bernardo, M; Regino, C. A. S.; Williams, M; Brechbiel, M. W.

2010-01-01

In this report we directly compare the in vivo and in vitro MRI properties of gadolinium-dendrimer conjugates of derivatized acyclic diethylenetriamine-N,N’,N’,N’’, N’’-pentaacetic acid (1B4M-DTPA) and macrocyclic 1,4,7,10-tetraazacyclododecane-N,N’,N’’,N’’’-tetraacetic acid (C-DOTA). The metal-ligand chelates were pre-formed in alcohol prior to conjugation to the generation 4 PAMAM dendrimer (G4D), and the dendrimer-based agents were purified by Sephadex® G-25 column. The analysis and SE-HPLC data indicated chelate to dendrimer ratios of 30:1 and 28:1 respectively. Molar relaxivity measured at pH 7.4, 22°C, and 3T are comparable (29.5 vs. 26.9 mM−1s−1), and both conjugates are equally viable as MRI contrast agents based on the images obtained. The macrocyclic agent however exhibits a faster rate of clearance in vivo (t1/2 = 16 vs. 29 min.). Our conclusion is that the macrocyclic-based agent is the more suitable agent for in vivo use for these reasons combined with kinetic inertness associated with the Gd(III) DOTA complex stability properties. PMID:20663676

Multifunctional nanoplatform for enhanced photodynamic cancer therapy and magnetic resonance imaging.

PubMed

Hao, Yongwei; Zhang, Bingxiang; Zheng, Cuixia; Niu, Mengya; Guo, Haochen; Zhang, Hongling; Chang, Junbiao; Zhang, Zhenzhong; Wang, Lei; Zhang, Yun

2017-03-01

Co-delivery of photosensitizers and synergistic agents by one single nanoplatform is interesting for enhancing photodynamic therapy (PDT) of cancer. Here, a multifunctional nanoplatform for enhanced photodynamic therapy and magnetic resonance imaging of cancer was constructed. The poly (lactide-co-glycolide) (PLGA) nanoparticles (NPs) loaded with hematoporphyrin monomethyl ether (HMME) were coated with multifunctional manganese dioxide (MnO 2 ) shells, which were designed as PLGA/HMME@MnO 2 NPs. Once the NPs were effectively taken up by tumor cells, the intracellular H 2 O 2 was catalysed by the MnO 2 shells to generate O 2 . Meanwhile, the higher glutathione (GSH) promoted the degradation of MnO 2 into Mn 2+ ions with the ability of magnetic resonance (MR) imaging. After the degradation of outer layer, the release of photosensitizer was promoted. Under irradiation, the released HMME produced cytotoxic reactive oxygen species (ROS) to damage the tumor cells when the O 2 was generated in the hypoxic tumor site. Furthermore, the decreased GSH level further inhibited the consumption of the produced ROS, which greatly enhanced the PDT efficacy. Therefore, this study suggested that this multifunctional system has the potential for enhanced photodynamic therapy and magnetic resonance imaging. Copyright © 2016 Elsevier B.V. All rights reserved.

Non-Hypervascular Hypointense Hepatic Nodules during the Hepatobiliary Phase of Gadolinium-Ethoxybenzyl-Diethylenetriamine Pentaacetic Acid-Enhanced MRI as a Risk Factor of Intrahepatic Distant Recurrence after Radiofrequency Ablation of Hepatocellular Carcinoma.

PubMed

Iwamoto, Takayuki; Imai, Yasuharu; Igura, Takumi; Kogita, Sachiyo; Sawai, Yoshiyuki; Fukuda, Kazuto; Yamaguchi, Yoshitaka; Matsumoto, Yasushi; Nakahara, Masanori; Morimoto, Osakuni; Ohashi, Hiroshi; Fujita, Norihiko; Kudo, Masatoshi; Takehara, Tetsuo

2017-01-01

Non-hypervascular hypointense hepatic nodules during the hepatobiliary phase of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI have been reported to be associated with intrahepatic distant recurrence (IDR) after hepatectomy or radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC). IDR is categorized into hypervascular transformation of non-hypervascular hypointense hepatic nodules and new intrahepatic recurrence. The aim of this study was to evaluate the relationship between non-hypervascular hypointense hepatic nodules on Gd-EOB-DTPA-enhanced MRI and IDR after RFA, focusing on new intrahepatic recurrence. Ninety-one consecutive patients with 115 HCCs undergoing pretreatment Gd-EOB-DTPA-enhanced MRI and RFA for treatment of HCC were enrolled. Of the 91 patients who underwent RFA for HCC, 24 had non-hypervascular hypointense hepatic nodules on pretreatment Gd-EOB-DTPA-enhanced MRI. Recurrences were observed in 15 and 19 patients with and without non-hypervascular hypointense hepatic nodules, respectively. Of the 15 recurrences in patients with non-hypervascular hypointense hepatic nodules, 10 patients had new intrahepatic recurrences. The cumulative incidence of new intrahepatic recurrence was significantly higher in patients with non-hypervascular hypointense hepatic nodules than in those without non-hypervascular hypointense hepatic nodules (p < 0.0001). Multivariate analysis revealed that the presence of non-hypervascular hypointense hepatic nodules and Child-Pugh score were independent risk factors for new intrahepatic recurrence. Non-hypervascular hypointense hepatic nodules during the hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI were a useful predictive factor for IDR, particularly for new intrahepatic recurrence, after RFA. © 2017 S. Karger AG, Basel.

Use of gadolinium-based magnetic resonance imaging contrast agents and awareness of brain gadolinium deposition among pediatric providers in North America.

PubMed

Mithal, Leena B; Patel, Payal S; Mithal, Divakar; Palac, Hannah L; Rozenfeld, Michael N

2017-05-01

Numerous recent articles have reported brain gadolinium deposition when using linear but not macrocyclic gadolinium-based contrast agents (GBCAs). To determine the current landscape of gadolinium use among pediatric institutions and the knowledge base of radiologists and referring providers with regard to GBCAs and brain gadolinium deposition. We e-mailed voluntary closed surveys to 5,390 physicians in various pediatric professional societies between January 2016 and March 2016. We used chi-square and Fisher exact tests to compare response distributions among specialties. We found that 80% of surveyed pediatric hospitals use macrocyclic contrast agents. In the last year, 58% switched their agent, most commonly to gadoterate meglumine, with the most common reason being brain gadolinium deposition. Furthermore, surveys indicated that 23% of hospitals are considering switching, and, of these, 83% would switch to gadoterate meglumine; the most common reasons were brain gadolinium deposition and safety. Radiologists were more aware of brain gadolinium deposition than non-radiologist physicians (87% vs. 26%; P<0.0001). Radiologists and referring providers expressed similar levels of concern (95% and 89%). Twelve percent of radiologists and 2% of referring providers reported patients asking about brain gadolinium deposition. Radiologists were significantly more comfortable addressing patient inquiries than referring pediatric physicians (48% vs. 6%; P<0.0001). The number of MRIs requested by referring pediatric physicians correlated with their knowledge of brain gadolinium deposition, contrast agent used by their hospital, and comfort discussing brain gadolinium deposition with patients (P<0.0001). Since the discovery of brain gadolinium deposition, many pediatric hospitals have switched to or plan to switch to a more stable macrocyclic MR contrast agent, most commonly gadoterate meglumine. Despite this, there is need for substantial further education of radiologists and

In Vivo Imaging of Immuno-Spin Trapped Radicals With Molecular Magnetic Resonance Imaging in a Diabetic Mouse Model

PubMed Central

Towner, Rheal A.; Smith, Nataliya; Saunders, Debra; Henderson, Michael; Downum, Kristen; Lupu, Florea; Silasi-Mansat, Robert; Ramirez, Dario C.; Gomez-Mejiba, Sandra E.; Bonini, Marcelo G.; Ehrenshaft, Marilyn; Mason, Ronald P.

2012-01-01

Oxidative stress plays a major role in diabetes. In vivo levels of membrane-bound radicals (MBRs) in a streptozotocin-induced diabetic mouse model were uniquely detected by combining molecular magnetic resonance imaging (mMRI) and immunotrapping techniques. An anti-DMPO (5,5-dimethyl-1-pyrroline N-oxide) antibody (Ab) covalently bound to an albumin (BSA)-Gd (gadolinium)-DTPA (diethylene triamine penta acetic acid)-biotin MRI contrast agent (anti-DMPO probe), and mMRI, were used to detect in vivo levels of DMPO-MBR adducts in kidneys, livers, and lungs of diabetic mice, after DMPO administration. Magnetic resonance signal intensities, which increase in the presence of a Gd-based molecular probe, were significantly higher within the livers, kidneys, and lungs of diabetic animals administered the anti-DMPO probe compared with controls. Fluorescence images validated the location of the anti-DMPO probe in excised tissues via conjugation of streptavidin-Cy3, which targeted the probe biotin moiety, and immunohistochemistry was used to validate the presence of DMPO adducts in diabetic mouse livers. This is the first report of noninvasively imaging in vivo levels of MBRs within any disease model. This method can be specifically applied toward diabetes models for in vivo assessment of free radical levels, providing an avenue to more fully understand the role of free radicals in diabetes. PMID:22698922

Increase in left liver lobe function after preoperative right portal vein embolisation assessed with gadolinium-EOB-DTPA MRI.

PubMed

Geisel, Dominik; Lüdemann, Lutz; Keuchel, Thomas; Malinowski, Maciej; Seehofer, Daniel; Stockmann, Martin; Hamm, Bernd; Gebauer, Bernhard; Denecke, Timm

2013-09-01

To prospectively evaluate the early development of regional liver function after right portal vein embolisation (PVE) with Gd-EOB-DTPA-enhanced MRI in patients scheduled for extended right hemihepatectomy. Ten patients who received a PVE before an extended hemihepatectomy were examined before and 14 days after PVE using Gd-EOB-DTPA-enhanced MRI of the liver. In these sequences representative region of interest measurements were performed in the embolised right (RLL) and the non-embolised left liver lobe (LLL). The volume as well as hepatic uptake index (HUI) was calculated independently for each lobe. Relative enhancement 14 days after PVE decreased in the RLL and increased significantly in the LLL (P < 0.05). Average hepatic uptake index (HUI) for RLL was significantly lower 14 days after PVE than before PVE (P < 0.05) and significantly higher for LLL (P < 0.05). A significant shift of contrast uptake from the right to the left liver lobe can be depicted as early as 14 days after right PVE by using Gd-EOB-DTPA-enhanced MRI, which could reflect the redirected portal venous blood flow and the rapid utilisation of a hepatic functional reserve. • Preoperative portal vein embolisation (PVE) is widely performed before right-sided hepatic resection. • PVE increases intravenous contrast medium uptake in the left lobe of liver. • The hepatic uptake index for the left liver lobe increases rapidly after PVE. • Left liver lobe function increase may be visualised by Gd-EOB-DTPA-enhanced MRI.

Biologically-compatible gadolinium(at)(carbon nanostructures) as advanced contrast agents for magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Sitharaman, Balaji

2005-11-01

Paramagnetic gadolinium-based carbon nanostructures are introduced as a new paradigm in high-performance magnetic resonance imaging (MRI) contrast agent (CA) design. Two Gd C60-based nanomaterials, Gd C60 [C(COOH)2]10 and Gd C60(OH)x are shown to have MRI efficacies (relaxivities) 5 to 20 times larger than any current Gd3+-based CA in clinical use. The first detailed and systematic physicochemical characterization was performed on these materials using the same experimental techniques usually applied to traditional Gd 3+-based CAs. Water-proton relaxivities were measured for the first time on these materials, as a function of magnetic field (5 x 10-4--9.4 T) to elucidate the different interaction mechanisms and dynamic processes influencing the relaxation behavior. These studies attribute the observed enhanced relaxivities completely to the "outer sphere" proton relaxation mechanism. These "outer sphere" relaxation effects are the largest reported for any Gd3+-based agent without inner-sphere water molecules. The proton relaxivities displayed a remarkable pH-dependency, increasing dramatically with decreasing pH (pH: 3--12). The increase in relaxivity resulted mainly from aggregation and subsequent three-order-of-magnitude increase in tauR, the rotational correlation time. Water-soluble fullerene materials (such as the neuroprotective fullerene drug, C3) readily cross cell membranes, suggesting an application for these gadofullerenes as the first intracellular, as well as pH-responsive MRI CAs. Studies performed at 60 MHz in the presence of phosphate-buffered saline (PBS, mice serum pH: 7.4) to mimic physiological conditions demonstrated that the aggregates can be disrupted by addition of salts, leading to a decrease in relaxivity. Biological fluids present a high salt concentration and should strongly modify the behavior of any fullerenes/metallofullerene-based drug in vivo. Gd C60[C(COOH)2]10 also showed enhanced relaxivity (23% increase) in the presence of the

Performance of magnetic resonance imaging in the evaluation of first-time and reoperative primary hyperparathyroidism.

PubMed

Kluijfhout, Wouter P; Venkatesh, Shriya; Beninato, Toni; Vriens, Menno R; Duh, Quan-Yang; Wilson, David M; Hope, Thomas A; Suh, Insoo

2016-09-01

Preoperative imaging in patients with primary hyperparathyroidism and a previous parathyroid operation is essential; however, performance of conventional imaging is poor in this subgroup. Magnetic resonance imaging appears to be a good alternative, though overall evidence remains scarce. We retrospectively investigated the performance of magnetic resonance imaging in patients with and without a previous parathyroid operation, with a separate comparison for dynamic gadolinium-enhanced magnetic resonance imaging. All patients undergoing magnetic resonance imaging prior to parathyroidectomy for primary hyperparathyroidism (first time or recurrent) between January 2000 and August 2015 at a high-volume, tertiary care, referral center for endocrine operations were included. We compared the sensitivity and positive predictive value of magnetic resonance imaging with conventional ultrasound and sestamibi on a per-lesion level. A total of 3,450 patients underwent parathyroidectomy, of which 84 patients with recurrent (n = 10) or persistent (n = 74) disease and 41 patients with a primary operation were included. Magnetic resonance imaging had a sensitivity and positive predictive value of 79.9% and 84.7%, respectively, and performance was good in both patients with and without a previous parathyroid operation. Adding magnetic resonance imaging to the combination of ultrasound and sestamibi resulted in a significant increase in sensitivity from 75.2% to 91.5%. Dynamic magnetic resonance imaging produced excellent results in the reoperative group, with sensitivity and a positive predictive value of 90.1%. Technologic advances have enabled faster and more accurate magnetic resonance imaging protocols, making magnetic resonance imaging an excellent alternative modality without associated ionizing radiation. Our study shows that the sensitivity of multimodality imaging for parathyroid adenomas improved significantly with the use of conventional and dynamic magnetic resonance

Magnetic Resonance Imaging of a Liver Hydatid Cyst Invading the Portal Vein and Causing Portal Cavernomatosis

PubMed Central

Herek, Duygu; Sungurtekin, Ugur

2015-01-01

Background Hepatic hydatid cysts rarely invade portal veins causing portal cavernomatosis as a secondary complication. Case Report We report the case of a patient with direct invasion of the right portal vein by hydatid cysts causing portal cavernomatosis diagnosed via magnetic resonance imaging (MRI). Conclusion The presented case highlights the useful application of MRI with T2-weighted images and gadolinium-enhanced T1-weighted images in the diagnosis of hepatic hydatid lesions presenting with a rare complication of portal cavernomatosis. PMID:26730239

Usefulness of the advanced neuroimaging protocol based on plain and gadolinium-enhanced constructive interference in steady state images for gamma knife radiosurgery and planning microsurgical procedures for skull base tumors.

PubMed

Hayashi, Motohiro; Chernov, Mikhail F; Tamura, Noriko; Yomo, Shoji; Tamura, Manabu; Horiba, Ayako; Izawa, Masahiro; Muragaki, Yoshihiro; Iseki, Hiroshi; Okada, Yoshikazu; Ivanov, Pavel; Régis, Jean; Takakura, Kintomo

2013-01-01

Gamma Knife radiosurgery (GKS) is currently performed with 0.1 mm preciseness, which can be designated microradiosurgery. It requires advanced methods for visualizing the target, which can be effectively attained by a neuroimaging protocol based on plain and gadolinium-enhanced constructive interference in steady state (CISS) images. Since 2003, the following thin-sliced images are routinely obtained before GKS of skull base lesions in our practice: axial CISS, gadolinium-enhanced axial CISS, gadolinium-enhanced axial modified time-of-flight (TOF), and axial computed tomography (CT). Fusion of "bone window" CT and magnetic resonance imaging (MRI), and detailed three-dimensional (3D) delineation of the anatomical structures are performed with the Leksell GammaPlan (Elekta Instruments AB). Recently, a similar technique has been also applied to evaluate neuroanatomy before open microsurgical procedures. Plain CISS images permit clear visualization of the cranial nerves in the subarachnoid space. Gadolinium-enhanced CISS images make the tumor "lucid" but do not affect the signal intensity of the cranial nerves, so they can be clearly delineated in the vicinity to the lesion. Gadolinium-enhanced TOF images are useful for 3D evaluation of the interrelations between the neoplasm and adjacent vessels. Fusion of "bone window" CT and MRI scans permits simultaneous assessment of both soft tissue and bone structures and allows 3D estimation and correction of MRI distortion artifacts. Detailed understanding of the neuroanatomy based on application of the advanced neuroimaging protocol permits performance of highly conformal and selective radiosurgical treatment. It also allows precise planning of the microsurgical procedures for skull base tumors.

Self-Gated Late Gadolinium Enhancement at 7T to Image Rats with Reperfused Acute Myocardial Infarction.

PubMed

Wang, Lei; Chen, Yushu; Zhang, Bing; Chen, Wei; Wang, Chunhua; Song, Li; Xu, Ziqian; Zheng, Jie; Gao, Fabao

2018-01-01

A failed electrocardiography (ECG)-trigger often leads to a long acquisition time (TA) and deterioration in image quality. The purpose of this study was to evaluate and optimize the technique of self-gated (SG) cardiovascular magnetic resonance (CMR) for cardiac late gadolinium enhancement (LGE) imaging of rats with myocardial infarction/reperfusion. Cardiovascular magnetic resonance images of 10 rats were obtained using SG-LGE or ECG with respiration double-gating (ECG-RESP-gating) method at 7T to compare differences in image interference and TA between the two methods. A variety of flip angles (FA: 10°-80°) and the number of repetitions (NR: 40, 80, 150, and 300) were investigated to determine optimal scan parameters of SG-LGE technique based on image quality score and contrast-to-noise ratio (CNR). Self-gated late gadolinium enhancement allowed successful scan in 10 (100%) rats. However, only 4 (40%) rats were successfully scanned with the ECG-RESP-gating method. TAs with SG-LGE varied depending on NR used (TA: 41, 82, 154, and 307 seconds, corresponding to NR of 40, 80, 150, and 300, respectively). For the ECG-RESP-gating method, the average TA was 220 seconds. For SG-LGE images, CNR (42.5 ± 5.5, 43.5 ± 7.5, 54 ± 9, 59.5 ± 8.5, 56 ± 13, 54 ± 8, and 41 ± 9) and image quality score (1.85 ± 0.75, 2.20 ± 0.83, 2.85 ± 0.37, 3.85 ± 0.52, 2.8 ± 0.51, 2.45 ± 0.76, and 1.95 ± 0.60) were achieved with different FAs (10°, 15°, 20°, 25°, 30°, 35°, and 40°, respectively). Optimal FAs of 20°-30° and NR of 80 were recommended. Self-gated technique can improve image quality of LGE without irregular ECG or respiration gating. Therefore, SG-LGE can be used an alternative method of ECG-RESP-gating.

Structural, optical and magnetic properties of gadolinium sesquioxide nanobars synthesized via thermal decomposition of gadolinium oxalate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manigandan, R.; Giribabu, K.; Suresh, R.

2013-10-15

Graphical abstract: - Highlights: • The cubic Gd{sub 2}O{sub 3} nanobars are synthesized by decomposition of C{sub 6}H{sub 20}Gd{sub 2}O{sub 22}. • The nanoparticles are rectangular bar shape with high porous surface. • The combination of magnetic and optical properties within a single particle. • The Gd{sub 2}O{sub 3} nanobars have tailorable nanostructure, wide bandgap and are paramagnetic. - Abstract: Gadolinium oxide nanobars were obtained by thermal decomposition of gadolinium oxalate, which was synthesized by the chemical precipitation method along with glycerol. The functional group analysis and formation of gadolinium oxide from gadolinium oxalate were characterized by the Fourier transformmore » infrared spectroscopy and thermo gravimetric analyzer. The crystal structure, average crystallite size, and lattice parameter were analyzed by X-ray diffraction technique. Moreover, Raman shifts, elemental composition and morphology of the gadolinium oxide was widely investigated by the laser Raman microscope, X-ray photoelectron spectroscopy, FE-SEM-EDAX and HR-TEM, respectively. Furthermore, the optical properties like band gap, absorbance measurement of the gadolinium oxide were extensively examined. In addition, the paramagnetic property of gadolinium oxide nanobars was explored by the vibrating sample magnetometer.« less

Normal spinal bone marrow in adults: dynamic gadolinium-enhanced MR imaging.

PubMed

Montazel, Jean-Luc; Divine, Marine; Lepage, Eric; Kobeiter, Hicham; Breil, Stephane; Rahmouni, Alain

2003-12-01

To determine the patterns of dynamic enhancement of normal spinal bone marrow in adults at gadolinium-enhanced magnetic resonance (MR) imaging and the changes that occur with aging. Dynamic contrast material-enhanced MR imaging of the thoracolumbar spine was performed in 71 patients. The maximum percentage of enhancement (Emax), enhancement slope, and enhancement washout were determined from bone marrow enhancement time curves (ETCs). The bone marrow signal intensity on T1-weighted spin-echo MR images was qualitatively classified into three grade categories. Quantitative ETC values were correlated with patient age and bone marrow fat content grade. Statistical analysis included mean t test comparison, analysis of variance, and regression analysis of the correlations between age and quantitative MR parameters. Emax, slope, and washout varied widely among the patients. Emax values were obtained within 1 minute after contrast material injection and ranged from 0% to 430%. Emax values were significantly higher in patients younger than 40 years than in those aged 40 years or older (P <.001). These values decreased with increasing age in a logarithmic relationship (r = 0.71). Emax values decreased as fat content increased, but some overlap among the fat content grades was noted. Analysis of variance revealed that Emax was significantly related to age (younger than 40 years vs 40 years or older) (P <.001) and fat content grade (P <.001) but not significantly related to sex. Dynamic contrast-enhanced MR imaging patterns of normal spinal bone marrow are dependent mainly on patient age and fat content.

Wideband late gadolinium enhanced magnetic resonance imaging for imaging myocardial scar without image artefacts induced by implantable cardioverter-defibrillator: a feasibility study at 3 T

PubMed Central

Ranjan, Ravi; McGann, Christopher J.; Jeong, Eun-Kee; Hong, KyungPyo; Kholmovski, Eugene G.; Blauer, Josh; Wilson, Brent D.; Marrouche, Nassir F.; Kim, Daniel

2015-01-01

Aim Late gadolinium enhanced (LGE) magnetic resonance imaging (MRI) is a useful tool for facilitating ventricular tachycardia (VT) ablation. Unfortunately, most VT ablation candidates often have prophylactic implantable cardioverter-defibrillator (ICD) and do not undergo cardiac MRI largely due to image artefacts generated by ICD. A prior study has reported success of ‘wideband’ LGE MRI for imaging myocardial scar without image artefacts induced by ICD at 1.5T. The purpose of this study was to widen the availability of wideband LGE MRI to 3T, since it has the potential to achieve higher spatial resolution than 1.5T. Methods and results We compared the performance of standard and wideband LGE MRI pulse sequences in phantoms and canines with myocardial lesions created by radiofrequency ablation. Standard LGE MRI produced image artefacts induced by ICD and 49% accuracy in detecting 97 myocardial scars examined in this study, whereas wideband LGE MRI produced artefact-free images and 94% accuracy in detecting scars. The mean image quality score (1 = nondiagnostic, 2 = poor, 3 = adequate, 4 = good, 5 = excellent) was significantly (P < 0.001) higher for wideband (3.7 ± 0.8) than for standard LGE MRI (2.1 ± 0.7). The mean artefact level score (1 = minimal, 2 = mild, 3 = moderate, 4 = severe, 5 = nondiagnostic) was significantly (P < 0.001) lower for wideband (2.1 ± 0.8) than for standard LGE MRI (4.0 ± 0.6). Wideband LGE MRI agreed better with gross pathology than standard LGE MRI. Conclusion This study demonstrates the feasibility of wideband LGE MRI for suppression of image artefacts induced by ICD at 3T. PMID:25336666

Usefulness of the dynamic gadolinium-enhanced magnetic resonance imaging with simultaneous acquisition of coronal and sagittal planes for detection of pituitary microadenomas.

PubMed

Lee, Han Bee; Kim, Sung Tae; Kim, Hyung-Jin; Kim, Keon Ha; Jeon, Pyoung; Byun, Hong Sik; Choi, Jin Wook

2012-03-01

Does dynamic gadolinium-enhanced imaging with simultaneous acquisition of coronal and sagittal planes improve diagnostic accuracy of pituitary microadenomas compared with coronal images alone? Fifty-six patients underwent 3-T sella MRI including dynamic simultaneous acquisition of coronal and sagittal planes after gadolinium injection. According to conspicuity, lesions were divided into four scores (0, no; 1, possible; 2, probable; 3, definite delayed enhancing lesion). Additional information on supplementary sagittal images compared with coronal ones was evaluated with a 4-point score (0, no; 1, possible; 2, probable; 3, definite additional information). Accuracy of tumour detection was calculated. Average scores for lesion detection of a combination of two planes, coronal, and sagittal images were 2.59, 2.32, and 2.18. 6/10 lesions negative on coronal images were detected on sagittal ones. Accuracy of a combination of two planes, of coronal and of sagittal images was 92.86%, 82.14% and 75%. Six patients had probable or definite additional information on supplementary sagittal images compared with coronal ones alone (10.71%). Dynamic MRI with combined coronal and sagittal planes was more accurate for detection of pituitary microadenomas than routinely used coronal images. Simultaneous dynamic enhanced acquisition can make study time fast and costs low. We present a new dynamic MRI technique for evaluating pituitary microadenomas • This technique provides simultaneous acquisition of contrast enhanced coronal and sagittal images. • This technique makes the diagnosis more accurate and reduces the examination time. • Such MR imaging only requires one single bolus of contrast agent.

Myocardial Tissue Characterization by Magnetic Resonance Imaging

PubMed Central

Ferreira, Vanessa M.; Piechnik, Stefan K.; Robson, Matthew D.; Neubauer, Stefan

2014-01-01

Cardiac magnetic resonance (CMR) imaging is a well-established noninvasive imaging modality in clinical cardiology. Its unsurpassed accuracy in defining cardiac morphology and function and its ability to provide tissue characterization make it well suited for the study of patients with cardiac diseases. Late gadolinium enhancement was a major advancement in the development of tissue characterization techniques, allowing the unique ability of CMR to differentiate ischemic heart disease from nonischemic cardiomyopathies. Using T2-weighted techniques, areas of edema and inflammation can be identified in the myocardium. A new generation of myocardial mapping techniques are emerging, enabling direct quantitative assessment of myocardial tissue properties in absolute terms. This review will summarize recent developments involving T1-mapping and T2-mapping techniques and focus on the clinical applications and future potential of these evolving CMR methodologies. PMID:24576837

State-of-the-art magnetic resonance imaging of pancreatic cancer.

PubMed

Schima, Wolfgang; Ba-Ssalamah, Ahmed; Goetzinger, Peter; Scharitzer, Martina; Koelblinger, Claus

2007-12-01

Technical advances of magnetic resonance imaging (MRI), including ultrahigh-field magnetic resonance at 3.0 T, parallel imaging techniques, and multichannel receive coils of the abdomen, have promoted MRI of the pancreas. For adenocarcinoma, which is the most common malignant pancreatic tumor, helical CT has been most often used for detection and staging, but it has limitations in the detection of small cancers 2 cm in diameter or less (sensitivity, 63%). Moreover, it is not very accurate in determining nonresectability, because small liver metastases, peritoneal carcinomatosis, and subtle signs of vascular infiltration may be missed. At ultrahigh field at 3.0 T, gadolinium-enhanced MRI using volume-interpolated 3-dimensional gradient-recalled echo pulse sequences with near-isotropic voxels are very useful for detection of subtle abnormalities. Mangafodipir-enhanced MRI reveals a very high tumor-pancreas contrast, which helps to diagnose small cancers. Contrast-enhanced MRI is a problem-solving tool in case of equivocal CT: it helps to differentiate between cancer and focal pancreatitis. Neuroendocrine carcinoma may present with a spectrum of appearances at MRI, but the primary tumor and liver metastases are hypervascular in approximately 70%. In this article, pancreas imaging protocols for 1.5 and 3.0 T are explained. We present the imaging features of pancreatic cancer and the important questions in staging, which should be addressed by the radiologist.

Serum Neutrophil Gelatinase-Associated Lipocalin and Urinary Kidney Injury Molecule-1 as Potential Biomarkers of Subclinical Nephrotoxicity After Gadolinium-Based and Iodinated-Based Contrast Media Exposure in Pediatric Patients with Normal Kidney Function

PubMed Central

Spasojević-Dimitrijeva, Brankica; Kotur-Stevuljević, Jelena; Đukić, Milan; Paripović, Dušan; Miloševski-Lomić, Gordana; Spasojević-Kalimanovska, Vesna; Pavićević, Polina; Mitrović, Jadranka; Kostić, Mirjana

2017-01-01

Background New renal biomarkers such as neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) show promise in early diagnosis of contrast media induced acute kidney injury (CI-AKI). The purpose of our study was to compare the subclinical nephrotoxicity (a condition without changes in standard renal biomarkers) of gadolinium-based contrast media (Gd-DTPA, gadopentetate dimeglumine) and iodinated-based contrast media (iopromide) in pediatric patients with normal kidney function. Material/Methods The first group (n=58) of patients included in the study were undergoing angiography with iopromide, and the second group (n=65) were undergoing magnetic resonance (MR) angiography/urography with Gd-DTPA administration. The concentrations of NGAL and KIM-1 were measured four times in the urine (pre-contrast, then at four hours, 24 hours, and 48 hours after contrast administration), and serum NGAL was measured at 0 (baseline), 24 hours, and 48 hours after contrast exposure. Results After 24 hours, serum NGAL increase of ≥25% was noticed in 32.6% of the patients in the iopromide group and in 25.45% of the patients in the gadolinium group, with significantly higher average percent of this increase in first group (62.23% vs. 36.44%, p=0.002). In the Gd-DTPA group, we observed a statistically significant increase in urinary KIM-1 24 hours after the procedure. Normalized urinary KIM-1, 24 hours after contrast exposure, was a better predictive factor for CI-AKI than other biomarkers (AUC 0.757, cut off 214 pg/mg, sensitivity 83.3%, specificity 54.2%, p=0.035). Conclusions In children with normal renal function, exposure to iodinated-based and gadolinium-based media might lead to subclinical nephrotoxicity, which could be detected using serum NGAL and urinary KIM-1. PMID:28874655

Enhancing Raman signals through electromagnetic hot zones induced by magnetic dipole resonance of metal-free nanoparticles

NASA Astrophysics Data System (ADS)

Tseng, Yi-Chuan; Lee, Yang-Chun; Chang, Sih-Wei; Lin, Tzu-Yao; Ma, Dai-Liang; Lin, Bo-Cheng; Chen, Hsuen-Li

2017-11-01

In this study, we found that the large area of electromagnetic field hot zone induced through magnetic dipole resonance of metal-free structures can greatly enhance Raman scattering signals. The magnetic resonant nanocavities, based on high-refractive-index silicon nanoparticles (SiNPs), were designed to resonate at the wavelength of the excitation laser of the Raman system. The well-dispersed SiNPs that were not closely packed displayed significant magnetic dipole resonance and gave a Raman enhancement per unit volume of 59 347. The hot zones of intense electric field were generated not only within the nonmetallic NPs but also around them, even within the underlying substrate. We observed experimentally that gallium nitride (GaN) and silicon carbide (SiC) surfaces presenting very few SiNPs (coverage: <0.3%) could display significantly enhanced (>50%) Raman signals. In contrast, the Raman signals of the underlying substrates were not enhanced by gold nanoparticles (AuNPs), even though these NPs displayed a localized surface plasmon resonance (LSPR) phenomenon. A comparison of the areas of the electric field hot zones (E 2 > 10) generated by SiNPs undergoing magnetic dipole resonance with the electric field hot spots (E 2 > 10) generated by AuNPs undergoing LSPR revealed that the former was approximately 70 times that of the latter. More noteworthily, the electromagnetic field hot zone generated from the SiNP is able to extend into the surrounding and underlying media. Relative to metallic NPs undergoing LSPR, these nonmetallic NPs displaying magnetic dipole resonance were more effective at enhancing the Raman scattering signals from analytes that were underlying, or even far away from, them. This application of magnetic dipole resonance in metal-free structures appears to have great potential for use in developing next-generation techniques for Raman enhancement.

Safety assessment of nanoparamagnetic contrast agents with different coatings for molecular MRI

NASA Astrophysics Data System (ADS)

Azizian, Gholamreza; Riyahi-Alam, Nader; Haghgoo, Soheila; Saffari, Mojtaba; Zohdiaghdam, Reza; Gorji, Ensieh

2013-04-01

Despite the wide application of gadolinium as a contrast agent for magnetic resonance imaging (MRI), there is a serious lack of information on its toxicity. Gadolinium and gadolinium oxide (Gd-oxide) are used as contrast agents for magnetic resonance imaging (MRI). There are methods for reducing toxicity of these materials, such as core nanoparticles coating or conjugating. Therefore, for toxicity evaluation, we compared the viability of commercial contrast agents in MRI (Gd-DTPA) and three nanoparticles with the same core Gd2O3 and small particulate gadolinium oxide or SPGO (< 40 nm) but different coatings of diethyleneglycol (DEG) as Gd2O3-DEG and methoxy polyethylene glycol-silane (mPEG-silane: 550 and 2000 Dalton) as SPGO-mPEG-silane550 and SPGO-mPEG-silane2000, respectively, in the SK-MEL3 cell line, by light microscopy, MTT assay using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide, and the LDH assay detecting lactate dehydrogenase activity. The viability values were not statistically different between the three nanoparticles and Gd-DTPA. The MTT and LDH assay results showed that Gd2O3-DEG nanoparticles were more toxic than Gd-DTPA and other nanoparticles. Also, SPGO-mPEG-silane2000 was more biocompatible than other nanoparticles. The obtained results did not show any significant increase in cytotoxicity of the nanoparticles and Gd-DTPA, neither dose-dependent nor time-dependent. Therefore, DEG and PEG, due to their considerable properties and irregular sizes (different molecular weights), were selected as the useful surface covering materials of nanomagnetic particles that could reveal noticeable relaxivity and biocompatibility characteristics.

Platinum(II)-gadolinium(III) complexes as potential single-molecular theranostic agents for cancer treatment.

PubMed

Zhu, Zhenzhu; Wang, Xiaoyong; Li, Tuanjie; Aime, Silvio; Sadler, Peter J; Guo, Zijian

2014-11-24

Theranostic agents are emerging multifunctional molecules capable of simultaneous therapy and diagnosis of diseases. We found that platinum(II)-gadolinium(III) complexes with the formula [{Pt(NH3)2Cl}2GdL](NO3)2 possess such properties. The Gd center is stable in solution and the cytoplasm, whereas the Pt centers undergo ligand substitution in cancer cells. The Pt units interact with DNA and significantly promote the cellular uptake of Gd complexes. The cytotoxicity of the Pt-Gd complexes is comparable to that of cisplatin at high concentrations (≥0.1 mM), and their proton relaxivity is higher than that of the commercial magnetic resonance imaging (MRI) contrast agent Gd-DTPA. T1-weighted MRI on B6 mice demonstrated that these complexes can reveal the accumulation of platinum drugs in vivo. Their cytotoxicity and imaging capabilities make the Pt-Gd complexes promising theranostic agents for cancer treatment. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gadolinium-enhanced MR images of the growing piglet skeleton: ionic versus nonionic contrast agent.

PubMed

Menezes, Nina M; Olear, Elizabeth A; Li, Xiaoming; Connolly, Susan A; Zurakowski, David; Foley, Mary; Shapiro, Frederic; Jaramillo, Diego

2006-05-01

To determine whether there are differences in the distribution of ionic and nonionic gadolinium-based contrast agents by evaluating contrast enhancement of the physis, epiphyseal cartilage, secondary ossification center, and metaphysis in the knees of normal piglets. Following approval from the Subcommittee on Research Animal Care, knees of 12 3-week-old piglets were imaged at 3-T magnetic resonance (MR) imaging after intravenous injection of gadoteridol (nonionic contrast agent; n = 6) or gadopentetate dimeglumine (ionic contrast agent; n = 6). Early enhancement evaluation with gradient-echo MR imaging was quantified and compared (Student t test) by means of enhancement ratios. Distribution of contrast material was assessed and compared (Student t test) by means of T1 measurements obtained before and at three 15-minute intervals after contrast agent administration. The relative visibility of the physis, epiphyseal cartilage, secondary ossification center, and metaphysis was qualitatively assessed by two observers and compared (Wilcoxon signed rank test). Differences in matrix content and cellularity that might explain the imaging findings were studied at histologic evaluation. Enhancement ratios were significantly higher for gadoteridol than for gadopentetate dimeglumine in the physis, epiphyseal cartilage, and secondary ossification center (P < .05). After contrast agent administration, T1 values decreased sharply for both agents-but more so for gadoteridol. Additionally, there was less variability in T1 values across structures with this contrast agent. Gadoteridol resulted in greater visibility of the physis, while gadopentetate dimeglumine resulted in greater contrast between the physis and metaphysis (P < .05). The results suggest different roles for the two gadolinium-based contrast agents: The nonionic contrast medium is better suited for evaluating perfusion and anatomic definition in the immature skeleton, while the ionic contrast medium is better for

Reticular Appearance on Gadolinium-enhanced T1- and Diffusion-weighted MRI, and Low Apparent Diffusion Coefficient Values in Microcystic Meningioma Cysts.

PubMed

Terada, Yukinori; Toda, Hiroki; Okumura, Ryosuke; Ikeda, Naokado; Yuba, Yoshiaki; Katayama, Toshiro; Iwasaki, Koichi

2018-03-01

Microcystic meningioma, a rare meningioma subtype, can present diagnostic difficulty. We aimed to investigate the historadiological properties of microcystic meningioma using conventional magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) analysis. We retrospectively analyzed conventional MRI and DWI results of six microcystic meningioma cases by examining their appearance and determining their apparent diffusion coefficient (ADC) values. The ADC values of the intratumoral components were normalized with ADC values of the cerebrospinal fluid in the lateral ventricle (ADC ratios). As cystic formations are frequently associated with microcystic meningiomas, their MRI characteristics were compared with the imaging data from 11 cystic meningiomas of non-microcystic subtypes. We found that cysts in microcystic meningioma tended to have a reticular appearance on DWI, as they did on gadolinium-enhanced T1-weighted imaging. Additionally, these reticular cysts had significantly lower ADC ratios than microcystic non-reticular and non-microcystic cysts. These DWI characteristics likely reflect the histological properties of microcystic meningioma. A reticular appearance on gadolinium-enhanced T1-weighted MRI and DWI, and cyst formation with relatively low ADC values can be diagnostic markers of microcystic meningiomas.

A simple and inexpensive system for controlling body temperature in small animal experiments using MRI and the effect of body temperature on the hepatic kinetics of Gd-EOB-DTPA.

PubMed

Murase, Kenya; Assanai, Purapan; Takata, Hiroshige; Saito, Shigeyoshi; Nishiura, Motoko

2013-12-01

The purpose of this study was to develop a simple and inexpensive system for controlling body temperature in small animal experiments using magnetic resonance imaging (MRI) and to investigate the effect of body temperature on the kinetic behavior of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) in the liver. In our temperature-control system, body temperature was controlled using a feedback-regulated heated or cooled air flow generated by two Futon dryers. The switches of the two Futon dryers were controlled using a digital temperature controller, in which the rectal temperature of a mouse measured by an optical fiber thermometer was used as the input. In experimental studies, male ICR mice aged 8weeks old were used and allocated into 5 groups (39-, 36-, 33-, 30-, and 27-degree groups, n=10), in which the body temperature was maintained at 39 °C, 36 °C, 33 °C, 30 °C, and 27 °C, respectively, using our system. The dynamic contrast-enhanced MRI (DCE-MRI) data were acquired with an MRI system for animal experiments equipped with a 1.5-Tesla permanent magnet, for approximately 43min, after the injection of Gd-EOB-DTPA into the tail vein. After correction of the image shift due to the temperature-dependent drift of the Larmor frequency using the gradient-based image registration method with robust estimation of displacement parameters, the kinetic behavior of Gd-EOB-DTPA was analyzed using an empirical mathematical model. With the use of this approach, the upper limit of the relative enhancement (A), the rates of contrast uptake (α) and washout (β), the parameter related to the slope of early uptake (q), the area under the curve (AUC), the maximum relative enhancement (REmax), the time to REmax (Tmax), and the elimination half-life of the contrast agent (T1/2) were calculated. The body temperature of mice could be controlled well by use of our system. Although there were no significant differences in α, AUC, and q among groups, there

Layered gadolinium hydroxides for low-temperature magnetic cooling.

PubMed

Abellán, Gonzalo; Espallargas, Guillermo Mínguez; Lorusso, Giulia; Evangelisti, Marco; Coronado, Eugenio

2015-09-28

Layered gadolinium hydroxides have revealed to be excellent candidates for cryogenic magnetic refrigeration. These materials behave as pure 2D magnetic systems with a Heisenberg-Ising critical crossover, induced by dipolar interactions. This 2D character and the possibility offered by these materials to be delaminated open the possibility of rapid heat dissipation upon substrate deposition.

Biodegradable human serum albumin nanoparticles as contrast agents for the detection of hepatocellular carcinoma by magnetic resonance imaging.

PubMed

Watcharin, Waralee; Schmithals, Christian; Pleli, Thomas; Köberle, Verena; Korkusuz, Hüdayi; Huebner, Frank; Zeuzem, Stefan; Korf, Hans W; Vogl, Thomas J; Rittmeyer, Claudia; Terfort, Andreas; Piiper, Albrecht; Gelperina, Svetlana; Kreuter, Jörg

2014-05-01

Tumor visualization by magnetic resonance imaging (MRI) and nanoparticle-based contrast agents may improve the imaging of solid tumors such as hepatocellular carcinoma (HCC). In particular, human serum albumin (HSA) nanoparticles appear to be a suitable carrier due to their safety and feasibility of functionalization. In the present study HSA nanoparticles were conjugated with gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) using carbodiimide chemistry. The nanoparticles had a uniform spherical shape and a diameter of 235±19nm. For better optical visualization in vitro and in vivo, the HSA-Gd nanoparticles were additionally labeled with rhodamine 123. As shown by confocal microscopy and flow cytometry analysis, the fluorescent nanoparticles were readily taken up by Huh-7 hepatocellular carcinoma cells. After 24h incubation in blood serum, less than 5% of the Gd(III) was released from the particles, which suggests that this nanoparticulate system may be stable in vivo and, therefore, may serve as potentially safe T1 MRI contrast agent for MRI of hepatocellular carcinoma. Copyright © 2013 Elsevier B.V. All rights reserved.

Geometrically confined ultrasmall gadolinium oxide nanoparticles boost the T1 contrast ability

NASA Astrophysics Data System (ADS)

Ni, Kaiyuan; Zhao, Zhenghuan; Zhang, Zongjun; Zhou, Zijian; Yang, Li; Wang, Lirong; Ai, Hua; Gao, Jinhao

2016-02-01

High-performance magnetic resonance imaging (MRI) contrast agents and novel contrast enhancement strategies are urgently needed for sensitive and accurate diagnosis. Here we report a strategy to construct a new T1 contrast agent based on the Solomon-Bloembergen-Morgan (SBM) theory. We loaded the ultrasmall gadolinium oxide nanoparticles into worm-like interior channels of mesoporous silica nanospheres (Gd2O3@MSN nanocomposites). This unique structure endows the nanocomposites with geometrical confinement, high molecular tumbling time, and a large coordinated number of water molecules, which results in a significant enhancement of the T1 contrast with longitudinal proton relaxivity (r1) as high as 45.08 mM-1 s-1. Such a high r1 value of Gd2O3@MSN, compared to those of ultrasmall Gd2O3 nanoparticles and gadolinium-based clinical contrast agents, is mainly attributed to the strong geometrical confinement effect. This strategy provides new guidance for developing various high-performance T1 contrast agents for sensitive imaging and disease diagnosis.High-performance magnetic resonance imaging (MRI) contrast agents and novel contrast enhancement strategies are urgently needed for sensitive and accurate diagnosis. Here we report a strategy to construct a new T1 contrast agent based on the Solomon-Bloembergen-Morgan (SBM) theory. We loaded the ultrasmall gadolinium oxide nanoparticles into worm-like interior channels of mesoporous silica nanospheres (Gd2O3@MSN nanocomposites). This unique structure endows the nanocomposites with geometrical confinement, high molecular tumbling time, and a large coordinated number of water molecules, which results in a significant enhancement of the T1 contrast with longitudinal proton relaxivity (r1) as high as 45.08 mM-1 s-1. Such a high r1 value of Gd2O3@MSN, compared to those of ultrasmall Gd2O3 nanoparticles and gadolinium-based clinical contrast agents, is mainly attributed to the strong geometrical confinement effect. This strategy

Novel cardiac magnetic resonance biomarkers: native T1 and extracellular volume myocardial mapping.

PubMed

Cannaò, Paola Maria; Altabella, Luisa; Petrini, Marcello; Alì, Marco; Secchi, Francesco; Sardanelli, Francesco

2016-04-28

Cardiac magnetic resonance (CMR) is a non-invasive diagnostic tool playing a key role in the assessment of cardiac morphology and function as well as in tissue characterization. Late gadolinium enhancement is a fundamental CMR technique for detecting focal or regional abnormalities such as scar tissue, replacement fibrosis, or inflammation using qualitative, semi-quantitative, or quantitative methods, but not allowing for evaluating the whole myocardium in the presence of diffuse disease. The novel T1 mapping approach permits a quantitative assessment of the entire myocardium providing a voxel-by-voxel map of native T1 relaxation time, obtained before the intravenous administration of gadolinium-based contrast material. Combining T1 data obtained before and after contrast injection, it is also possible to calculate the voxel-by-voxel extracellular volume (ECV), resulting in another myocardial parametric map. This article describes technical challenges and clinical perspectives of these two novel CMR biomarkers: myocardial native T1 and ECV mapping.

Enhanced photoelectric detection of NV magnetic resonances in diamond under dual-beam excitation

NASA Astrophysics Data System (ADS)

Bourgeois, E.; Londero, E.; Buczak, K.; Hruby, J.; Gulka, M.; Balasubramaniam, Y.; Wachter, G.; Stursa, J.; Dobes, K.; Aumayr, F.; Trupke, M.; Gali, A.; Nesladek, M.

2017-01-01

The core issue for the implementation of NV center qubit technology is a sensitive readout of the NV spin state. We present here a detailed theoretical and experimental study of NV center photoionization processes, used as a basis for the design of a dual-beam photoelectric method for the detection of NV magnetic resonances (PDMR). This scheme, based on NV one-photon ionization, is significantly more efficient than the previously reported single-beam excitation scheme. We demonstrate this technique on small ensembles of ˜10 shallow NVs implanted in electronic grade diamond (a relevant material for quantum technology), on which we achieve a cw magnetic resonance contrast of 9%—three times enhanced compared to previous work. The dual-beam PDMR scheme allows independent control of the photoionization rate and spin magnetic resonance contrast. Under a similar excitation, we obtain a significantly higher photocurrent, and thus an improved signal-to-noise ratio, compared to single-beam PDMR. Finally, this scheme is predicted to enhance magnetic resonance contrast in the case of samples with a high proportion of substitutional nitrogen defects, and could therefore enable the photoelectric readout of single NV spins.

Gadolinium-Functionalized Peptide Amphiphile Micelles for Multimodal Imaging of Atherosclerotic Lesions

PubMed Central

2016-01-01

The leading causes of morbidity and mortality globally are cardiovascular diseases, and nanomedicine can provide many improvements including disease-specific targeting, early detection, and local delivery of diagnostic agents. To this end, we designed fibrin-binding, peptide amphiphile micelles (PAMs), achieved by incorporating the targeting peptide cysteine-arginine-glutamic acid-lysine-alanine (CREKA), with two types of amphiphilic molecules containing the gadoliniuim (Gd) chelator diethylenetriaminepentaacetic acid (DTPA), DTPA-bis(stearylamide)(Gd), and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[(poly(ethylene glycol) (PEG))-2000]-DTPA(Gd) (DSPE-PEG2000-DTPA(Gd)). The material characteristics of the resulting nanoparticle diagnostic probes, clot-binding properties in vitro, and contrast enhancement and safety for dual, optical imaging–magnetic resonance imaging (MRI) were evaluated in the atherosclerotic mouse model. Transmission electron micrographs showed a homogenous population of spherical micelles for formulations containing DSPE-PEG2000-DTPA(Gd), whereas both spherical and cylindrical micelles were formed upon mixing DTPA-BSA(Gd) and CREKA amphiphiles. Clot-binding assays confirmed DSPE-PEG2000-DTPA(Gd)-based CREKA micelles targeted clots over 8-fold higher than nontargeting (NT) counterpart micelles, whereas no difference was found between CREKA and NT, DTPA-BSA(Gd) micelles. However, in vivo MRI and optical imaging studies of the aortas and hearts showed fibrin specificity was conferred by the peptide ligand without much difference between the nanoparticle formulations or shapes. Biodistribution studies confirmed that all micelles were cleared through both the reticuloendothelial system and renal clearance, and histology showed no signs of necrosis. In summary, these studies demonstrate the successful synthesis, and the molecular imaging capabilities of two types of CREKA-Gd PAMs for atherosclerosis. Moreover, we demonstrate the differences in

Photoexcited Graphene Metasurfaces: Significantly Enhanced and Tunable Magnetic Resonances

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fan, Yuancheng; Shen, Nian -Hai; Zhang, Fuli

Artificially constructed metamaterials or metasurfaces with tailored resonant elements provide a revolutionary platform for controlling light at the subwavelength scale. Switchable or frequency-agile meta-devices are highly desirable in achieving more flexible functionalities and have been explored extensively by incorporating various materials, which respond to external stimuli. Graphene, a two-dimensional material showing extraordinary physical properties, has been found very promising for tunable meta-devices. However, the high intrinsic loss of graphene severely obstructs us from achieving high-quality resonance in various graphene metamaterials and metasurfaces, and the loss compensation can be considered as a straightforward strategy to take further advantages of enhanced light–graphenemore » interactions. Here, we demonstrate that the photoexcited graphene, in which the quasi-Fermi energy of graphene changes corresponding to optical pumping, can boost the originally extremely weak magnetic resonance in a graphene split-ring metasurface, showing remarkable modulations in the transmission. In conclusion, our work pioneers the possibilities of optically pumped graphene metasurfaces for significant enhancement of resonances and feasible modulations.« less

Photoexcited Graphene Metasurfaces: Significantly Enhanced and Tunable Magnetic Resonances

DOE PAGES

Fan, Yuancheng; Shen, Nian -Hai; Zhang, Fuli; ...

2018-02-27

Artificially constructed metamaterials or metasurfaces with tailored resonant elements provide a revolutionary platform for controlling light at the subwavelength scale. Switchable or frequency-agile meta-devices are highly desirable in achieving more flexible functionalities and have been explored extensively by incorporating various materials, which respond to external stimuli. Graphene, a two-dimensional material showing extraordinary physical properties, has been found very promising for tunable meta-devices. However, the high intrinsic loss of graphene severely obstructs us from achieving high-quality resonance in various graphene metamaterials and metasurfaces, and the loss compensation can be considered as a straightforward strategy to take further advantages of enhanced light–graphenemore » interactions. Here, we demonstrate that the photoexcited graphene, in which the quasi-Fermi energy of graphene changes corresponding to optical pumping, can boost the originally extremely weak magnetic resonance in a graphene split-ring metasurface, showing remarkable modulations in the transmission. In conclusion, our work pioneers the possibilities of optically pumped graphene metasurfaces for significant enhancement of resonances and feasible modulations.« less

Convection-enhanced drug delivery of interleukin-4 Pseudomonas exotoxin (PRX321): increased distribution and magnetic resonance monitoring.

PubMed

Mardor, Y; Last, D; Daniels, D; Shneor, R; Maier, S E; Nass, D; Ram, Z

2009-08-01

Convection-enhanced drug delivery (CED) enables achieving a drug concentration within brain tissue and brain tumors that is orders of magnitude higher than by systemic administration. Previous phase I/II clinical trials using intratumoral convection of interleukin-4 Pseudomonas exotoxin (PRX321) have demonstrated an acceptable safety and toxicity profile with promising signs of therapeutic activity. The present study was designed to assess the distribution efficiency and toxicity of this PRX321 using magnetic resonance imaging (MRI) and to test whether reformulation with increased viscosity could enhance drug distribution. Convection of low- [0.02% human serum albumin (HSA)] and high-viscosity (3% HSA) infusates mixed with gadolinium-diethylenetriamine pentaacetic acid and PRX321 were compared with low- and high-viscosity infusates without the drug, in normal rat brains. MRI was used for assessment of drug distribution and detection of early and late toxicity. Representative brain samples were subjected to histological examination. Distribution volumes calculated from the magnetic resonance images showed that the average distribution of 0.02% HSA was larger than that of 0.02% HSA with PRX321 by a factor of 1.98 (p < 0.02). CED of 3.0% HSA, with or without PRX321, tripled the volume of distribution compared with 0.02% HSA with PRX321 (p < 0.015). No drug-related toxicity was detected. These results suggest that the impeded convection of the PRX321 infusate used in previous clinical trials can be reversed by increasing infusate viscosity and lead to tripling of the volume of distribution. This effect was not associated with any detectable toxicity. A similar capability to reverse impeded convection was also demonstrated in a CED model using acetic acid. These results will be implemented in an upcoming phase IIb PRX321 CED trial with a high-viscosity infusate.

IMAGING DIAGNOSIS-MAGNETIC RESONANCE IMAGING FEATURES OF CRANIOMANDIBULAR OSTEOPATHY IN AN AIREDALE TERRIER.

PubMed

Matiasovic, Matej; Caine, Abby; Scarpante, Elena; Cherubini, Giunio Bruto

2016-05-01

An Airedale Terrier was presented for evaluation of depression and reluctance to be touched on the head. Magnetic resonance (MR) imaging of the head was performed. The images revealed bone lesions affecting the calvarium at the level of the coronal suture and left mandibular ramus, with focal cortical destruction, expansion, and reactive new bone formation. Skull lesions were hypointense on T1-weighted sequences, hyperintense on T2-weighted sequences, and showed an intense and homogeneous enhancement after gadolinium administration. Reactive new bone formation and periosteal proliferation were confirmed histopathologically. The clinical signs, imaging findings, and histopathological examination were consistent with craniomandibular osteopathy. © 2015 American College of Veterinary Radiology.

Polydisulfide Manganese(II) Complexes as Non-Gadolinium Biodegradable Macromolecular MRI Contrast Agents

PubMed Central

Ye, Zhen; Jeong, Eun-Kee; Wu, Xueming; Tan, Mingqian; Yin, Shouyu; Lu, Zheng-Rong

2011-01-01

Purpose To develop safe and effective manganese(II) based biodegradable macromolecular MRI contrast agents. Materials and Methods In this study, we synthesized and characterized two polydisulfide manganese(II) complexes, Mn-DTPA cystamine copolymers and Mn-EDTA cystamine copolymers, as new biodegradable macromolecular MRI contrast agents. The contrast enhancement of the two manganese based contrast agents were evaluated in mice bearing MDA-MB-231 human breast carcinoma xenografts, in comparison with MnCl2. Results The T1 and T2 relaxivities were 4.74 and 10.38 mM−1s−1 per manganese at 3T for Mn-DTPA cystamine copolymers (Mn=30.50 kDa) and 6.41 and 9.72 mM−1s−1 for Mn-EDTA cystamine copolymers (Mn= 61.80 kDa). Both polydisulfide Mn(II) complexes showed significant liver, myocardium and tumor enhancement. Conclusion The manganese based polydisulfide contrast agents have a potential to be developed as alternative non-gadolinium contrast agents for MR cancer and myocardium imaging. PMID:22031457

Detecting liver fibrosis with Gd-EOB-DTPA-enhanced MRI: A confirmatory study.

PubMed

Verloh, Niklas; Utpatel, Kirsten; Haimerl, Michael; Zeman, Florian; Beyer, Lukas; Fellner, Claudia; Brennfleck, Frank; Dahlke, Marc H; Stroszczynski, Christian; Evert, Matthias; Wiggermann, Philipp

2018-04-18

Strong correlations between the grade of fibrosis and cirrhosis, classified using the Ishak scoring system, and the uptake characteristics of Gd-EOB-DTPA with the relative enhancement (RE) of the liver parenchyma have been reported. To confirm the results of a retrospective analysis, patients undergoing liver surgery were prospectively examined with Gd-EOB-DTPA-enhanced liver 3 Tesla MRI to determine the degree of liver fibrosis. Correlations between the grade of fibrosis and cirrhosis, classified using the Ishak scoring system, and RE were investigated and compared with those derived from an initial retrospective study. After validating the cut-off values in the retrospective study (Ishak ≥ 1, RE-cut-off 0.90; Ishak ≥ 2, RE-cut-off 0.79; Ishak ≥ 4, RE-cut-off 0.60; and Ishak = 6, RE-cut-off 0.47), we showed that Gd-EOB-DTPA has a high sensitivity (≥86%) and a high positive predictive value (≥86%). These results support the use of Gd-EOB-DTPA-enhanced liver MRI as a non-invasive method for determining the degree of liver fibrosis and cirrhosis.

Biocompatible Polyhydroxyethylaspartamide-based Micelles with Gadolinium for MRI Contrast Agents

PubMed Central

2010-01-01

Biocompatible poly-[N-(2-hydroxyethyl)-d,l-aspartamide]-methoxypoly(ethyleneglycol)-hexadecylamine (PHEA-mPEG-C16) conjugated with 1,4,7,10-tetraazacyclododecan-1,4,7,10-tetraacetic acid-gadolinium (DOTA-Gd) via ethylenediamine (ED) was synthesized as a magnetic resonance imaging (MRI) contrast agent. Amphiphilic PHEA-mPEG-C16-ED-DOTA-Gd forms micelle in aqueous solution. All the synthesized materials were characterized by proton nuclear magnetic resonance (1H NMR). Micelle size and shape were examined by dynamic light scattering (DLS) and atomic force microscopy (AFM). Micelles with PHEA-mPEG-C16-ED-DOTA-Gd showed higher relaxivities than the commercially available gadolinium contrast agent. Moreover, the signal intensity of a rabbit liver was effectively increased after intravenous injection of PHEA-mPEG-C16-ED-DOTA-Gd. PMID:21170410

Biocompatible Polyhydroxyethylaspartamide-based Micelles with Gadolinium for MRI Contrast Agents

NASA Astrophysics Data System (ADS)

Jeong, Sang Young; Kim, Hyo Jeong; Kwak, Byung-Kook; Lee, Ha-Young; Seong, Hasoo; Shin, Byung Cheol; Yuk, Soon Hong; Hwang, Sung-Joo; Cho, Sun Hang

2010-12-01

Biocompatible poly-[ N-(2-hydroxyethyl)- d, l-aspartamide]-methoxypoly(ethyleneglycol)-hexadecylamine (PHEA-mPEG-C16) conjugated with 1,4,7,10-tetraazacyclododecan-1,4,7,10-tetraacetic acid-gadolinium (DOTA-Gd) via ethylenediamine (ED) was synthesized as a magnetic resonance imaging (MRI) contrast agent. Amphiphilic PHEA-mPEG-C16-ED-DOTA-Gd forms micelle in aqueous solution. All the synthesized materials were characterized by proton nuclear magnetic resonance (1H NMR). Micelle size and shape were examined by dynamic light scattering (DLS) and atomic force microscopy (AFM). Micelles with PHEA-mPEG-C16-ED-DOTA-Gd showed higher relaxivities than the commercially available gadolinium contrast agent. Moreover, the signal intensity of a rabbit liver was effectively increased after intravenous injection of PHEA-mPEG-C16-ED-DOTA-Gd.

The Utility of Cardiac Magnetic Resonance Imaging in the Diagnosis of Cardiac Sarcoidosis.

PubMed

Stanton, Kelly M; Ganigara, Madhusudan; Corte, Peter; Celermajer, David S; McGuire, Mark A; Torzillo, Paul J; Corte, Tamera J; Puranik, Rajesh

2017-11-01

Autopsy reports suggest that cardiac sarcoidosis occurs in 20 to 25% of patients with pulmonary sarcoidosis, yet the clinical ante-mortem diagnosis is made in only 5% of cases. Current diagnostic algorithms are complex and lack sensitivity. Cardiac Magnetic Resonance imaging (CMR) provides an opportunity to detect myocardial involvement in sarcoidosis. The aim of this study is to determine the prevalence and clinical significance of late gadolinium enhancement (LGE) on CMR in patients with sarcoidosis. Consecutive patients with biopsy-proven sarcoidosis undergoing CMR were retrospectively evaluated for cardiac sarcoidosis. Medical records were correlated with CMR. Forty-six patients were evaluated. Late gadolinium enhancement was present in 22%, indicating myocardial involvement, and 70% had corresponding hyper-intense T2 signal indicating active inflammation. Late gadolinium enhancement was 18%+/-9.7% of overall left ventricular (LV) mass and most commonly located in the basal to mid septum. There was no association between LGE and cardiovascular symptoms or pulmonary stage. Eighty per cent of patients with LGE did not fulfill conventional diagnostic criteria for cardiac sarcoidosis. However, LGE was associated with clinically significant arrhythmia (p<0.01) and a lower LVEF (p=0.04). Using CMR, we identified a higher prevalence of cardiac sarcoidosis than previously reported clinical studies, a prevalence which is more consistent with autopsy data. The presence of LGE was highly correlated with clinically significant arrhythmias and lower LVEF. Copyright © 2017 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). All rights reserved.

Is 3-Tesla Gd-EOB-DTPA-Enhanced MRI with Diffusion-Weighted Imaging Superior to 64-Slice Contrast-Enhanced CT for the Diagnosis of Hepatocellular Carcinoma?

PubMed Central

Maiwald, Bettina; Lobsien, Donald; Kahn, Thomas; Stumpp, Patrick

2014-01-01

Objectives To compare 64-slice contrast-enhanced computed tomography (CT) with 3-Tesla magnetic resonance imaging (MRI) using Gd-EOB-DTPA for the diagnosis of hepatocellular carcinoma (HCC) and evaluate the utility of diffusion-weighted imaging (DWI) in this setting. Methods 3-phase-liver-CT was performed in fifty patients (42 male, 8 female) with suspected or proven HCC. The patients were subjected to a 3-Tesla-MRI-examination with Gd-EOB-DTPA and diffusion weighted imaging (DWI) at b-values of 0, 50 and 400 s/mm2. The apparent diffusion coefficient (ADC)-value was determined for each lesion detected in DWI. The histopathological report after resection or biopsy of a lesion served as the gold standard, and a surrogate of follow-up or complementary imaging techniques in combination with clinical and paraclinical parameters was used in unresected lesions. Diagnostic accuracy, sensitivity, specificity, and positive and negative predictive values were evaluated for each technique. Results MRI detected slightly more lesions that were considered suspicious for HCC per patient compared to CT (2.7 versus 2.3, respectively). ADC-measurements in HCC showed notably heterogeneous values with a median of 1.2±0.5×10−3 mm2/s (range from 0.07±0.1 to 3.0±0.1×10−3 mm2/s). MRI showed similar diagnostic accuracy, sensitivity, and positive and negative predictive values compared to CT (AUC 0.837, sensitivity 92%, PPV 80% and NPV 90% for MRI vs. AUC 0.798, sensitivity 85%, PPV 79% and NPV 82% for CT; not significant). Specificity was 75% for both techniques. Conclusions Our study did not show a statistically significant difference in detection in detection of HCC between MRI and CT. Gd-EOB-DTPA-enhanced MRI tended to detect more lesions per patient compared to contrast-enhanced CT; therefore, we would recommend this modality as the first-choice imaging method for the detection of HCC and therapeutic decisions. However, contrast-enhanced CT was not inferior in our study, so

Microwave-induced thermoacoustic computed tomography with a clinical contrast agent of NMG2[Gd(DTPA)

NASA Astrophysics Data System (ADS)

Qin, Huan; Yang, Sihua; Xing, Da

2012-01-01

NMG2[Gd(DTPA)], a clinical contrast agent, was investigated for microwave-induced thermoacoustic computed tomography (CT). Due to ionic conduction and magnetic dipole rotation in the presence of microwave field, microwave energy absorbed by NMG2[Gd(DTPA)] would be transformed to thermoacoustic signals based on the thermoelastic effect. The experimental results demonstrated that NMG2[Gd(DTPA)] at a concentration of 10 mM provided effective enhancement compared with water. The enhancement of NMG2[Gd(DTPA)] for thermoacoustic CT was further demonstrated in invivo tumor-bearing mouse. The theory and experimental results indicate that the clinically available NMG2[Gd(DTPA)] will promote the medical applications of thermoacoustic CT.

Semi-automated scar detection in delayed enhanced cardiac magnetic resonance images

NASA Astrophysics Data System (ADS)

Morisi, Rita; Donini, Bruno; Lanconelli, Nico; Rosengarden, James; Morgan, John; Harden, Stephen; Curzen, Nick

2015-06-01

Late enhancement cardiac magnetic resonance images (MRI) has the ability to precisely delineate myocardial scars. We present a semi-automated method for detecting scars in cardiac MRI. This model has the potential to improve routine clinical practice since quantification is not currently offered due to time constraints. A first segmentation step was developed for extracting the target regions for potential scar and determining pre-candidate objects. Pattern recognition methods are then applied to the segmented images in order to detect the position of the myocardial scar. The database of late gadolinium enhancement (LE) cardiac MR images consists of 111 blocks of images acquired from 63 patients at the University Hospital Southampton NHS Foundation Trust (UK). At least one scar was present for each patient, and all the scars were manually annotated by an expert. A group of images (around one third of the entire set) was used for training the system which was subsequently tested on all the remaining images. Four different classifiers were trained (Support Vector Machine (SVM), k-nearest neighbor (KNN), Bayesian and feed-forward neural network) and their performance was evaluated by using Free response Receiver Operating Characteristic (FROC) analysis. Feature selection was implemented for analyzing the importance of the various features. The segmentation method proposed allowed the region affected by the scar to be extracted correctly in 96% of the blocks of images. The SVM was shown to be the best classifier for our task, and our system reached an overall sensitivity of 80% with less than 7 false positives per patient. The method we present provides an effective tool for detection of scars on cardiac MRI. This may be of value in clinical practice by permitting routine reporting of scar quantification.

The magnetic, relaxometric, and optical properties of gadolinium-catalyzed single walled carbon nanotubes

NASA Astrophysics Data System (ADS)

Sitharaman, Balaji; Jacobson, Barry D.; Wadghiri, Youssef Z.; Bryant, Henry; Frank, Joseph

2013-04-01

We report the magnetic behavior, relaxometry, phantom magnetic resonance imaging (MRI), and near-infrared (NIR) photoluminescence spectroscopy of gadolinium (Gd) catalyzed single-walled carbon nanotubes (Gd-SWCNTs). Gd-SWCNTs are paramagnetic with an effective magnetic moment of 7.29 μB. Gd-SWCNT solutions show high r1 and r2 relaxivities at very low (0.01 MHz) to clinically relevant (61 MHz) magnetic fields (r1 ≥ 130 mM-1 s-1, r2 ≥ 160 mM-1 s-1). Analysis of nuclear magnetic resonance dispersion profiles using Solomon, Bloembergen, and Morgan equations suggests that multiple structural and dynamic parameters such as rotational correlation time τR, rate of water exchange τM, and the number of fast-exchanging water molecules within the inner sphere q may be responsible for the increase in r1 and r2 relaxivity. The T1 weighted MRI signal intensity (gradient echo sequence; repetition time (TR) = 66 ms, echo time (TE) = 3 ms, flop angle = 108°) of Gd-SWCNT phantom solution is 14 times greater than the Gd-based clinical MRI contrast agent Magnevist. Additionally, these nanotubes exhibit near infrared fluorescence with distinct E11 transitions of several semiconducting SWCNTs. Taken together, these results demonstrate that Gd-SWCNTs have potential as a novel, highly efficacious, multimodal MRI-NIR optical imaging contrast agent.

Cardiovascular magnetic resonance physics for clinicians: part II

PubMed Central

2012-01-01

This is the second of two reviews that is intended to cover the essential aspects of cardiovascular magnetic resonance (CMR) physics in a way that is understandable and relevant to clinicians using CMR in their daily practice. Starting with the basic pulse sequences and contrast mechanisms described in part I, it briefly discusses further approaches to accelerate image acquisition. It then continues by showing in detail how the contrast behaviour of black blood fast spin echo and bright blood cine gradient echo techniques can be modified by adding rf preparation pulses to derive a number of more specialised pulse sequences. The simplest examples described include T2-weighted oedema imaging, fat suppression and myocardial tagging cine pulse sequences. Two further important derivatives of the gradient echo pulse sequence, obtained by adding preparation pulses, are used in combination with the administration of a gadolinium-based contrast agent for myocardial perfusion imaging and the assessment of myocardial tissue viability using a late gadolinium enhancement (LGE) technique. These two imaging techniques are discussed in more detail, outlining the basic principles of each pulse sequence, the practical steps required to achieve the best results in a clinical setting and, in the case of perfusion, explaining some of the factors that influence current approaches to perfusion image analysis. The key principles of contrast-enhanced magnetic resonance angiography (CE-MRA) are also explained in detail, especially focusing on timing of the acquisition following contrast agent bolus administration, and current approaches to achieving time resolved MRA. Alternative MRA techniques that do not require the use of an endogenous contrast agent are summarised, and the specialised pulse sequence used to image the coronary arteries, using respiratory navigator gating, is described in detail. The article concludes by explaining the principle behind phase contrast imaging techniques

Nephrogenic systemic fibrosis (NSF): a late adverse reaction to some of the gadolinium based contrast agents

PubMed Central

Marckmann, Peter; Logager, Vibeke B.

2007-01-01

Abstract Until recently it was believed that extracellular gadolinium based contrast agents were safe for both the kidneys and all other organs within the dose range up to 0.3 mmol/kg body weight. However, in 2006, it was demonstrated that some gadolinium based contrast agents may trigger the development of nephrogenic systemic fibrosis, a generalised fibrotic disorder, in renal failure patients. Accordingly, the use of gadodiamide and gadopentate dimeglumine for renal failure patients was banned in Europe in spring 2007. The same two compounds should only be used cautiously in patients with moderate renal dysfunction. The current paper reviews the situation (July 2007) regarding gadolinium based contrast agent and the severe delayed reaction to some of these agents. The fear of nephrogenic systemic fibrosis should not lead to a denial of a well indicated enhanced magnetic resonance imaging examination. PMID:17905680

Impact of Impaired Renal Function on Gadolinium Retention After Administration of Gadolinium-Based Contrast Agents in a Mouse Model.

PubMed

Kartamihardja, A Adhipatria P; Nakajima, Takahito; Kameo, Satomi; Koyama, Hiroshi; Tsushima, Yoshito

2016-10-01

The aim of this study was to investigate the impact of impaired renal function on gadolinium (Gd) retention in various organs after Gd-based contrast agent injection. After local animal care and review committee approval, 23 normal mice and 26 with renal failure were divided into 4 treatment groups (Gd-DTPA-BMA, 5 mmol/kg; Gd-DOTA, 5 mmol/kg; GdCl3, 0.02 mmol/kg; and saline, 250 μL). Each agent was intravenously administered on weekdays for 4 weeks. Samples were collected on days 3 (short-term) and 45 (long-term) after the last injection. Gadolinium concentrations were quantified by inductively coupled plasma-mass spectrometry. Three mice with renal failure and 2 normal mice in the GdCl3 group and 1 mouse with renal failure in the Gd-DTPA-BMA group died. In the Gd-DTPA-BMA group, impaired renal function increased short-term Gd retention in the liver, bone, spleen, skin, and kidney (P < 0.01) but did not affect long-term Gd retention. Gd-DTPA-BMA showed higher Gd retention than Gd-DOTA. Although Gd retention in the Gd-DOTA group was generally low, impaired renal function increased only long-term hepatic Gd retention. Hepatic and splenic Gd retentions were significantly higher than other organs' Gd retention in the GdCl3 group (P < 0.01). Renal function did not affect brain Gd retention, regardless of the Gd compound used. The tendency of Gd retention varied according to the agent, regardless of renal function. Although renal impairment increased short-term Gd retention after Gd-DTPA-BMA administration, long-term Gd retention for Gd-based contrast agents was almost unaffected by renal function, suggesting that the chemical structures of retained Gd may not be consistent and some Gd is slowly eliminated after initially being retained.

Effect of Renal Function on Gadolinium-Related Signal Increases on Unenhanced T1-Weighted Brain Magnetic Resonance Imaging.

PubMed

Cao, Yan; Zhang, Yang; Shih, George; Zhang, Yan; Bohmart, Andrew; Hecht, Elizabeth M; Prince, Martin R

2016-11-01

patients receiving linear GBCA have greater dentate nucleus signal increases on unenhanced T1-weighted images, suggesting that renal function may affect the rate of gadolinium accumulation in the brain after linear GBCA-enhanced magnetic resonance imaging.

Pulsed Magnetic Resonance to Signal-Enhance Metabolites within Seconds by utilizing para-Hydrogen.

PubMed

Korchak, Sergey; Yang, Shengjun; Mamone, Salvatore; Glöggler, Stefan

2018-05-01

Diseases such as Alzheimer's and cancer have been linked to metabolic dysfunctions, and further understanding of metabolic pathways raises hope to develop cures for such diseases. To broaden the knowledge of metabolisms in vitro and in vivo, methods are desirable for direct probing of metabolic function. Here, we are introducing a pulsed nuclear magnetic resonance (NMR) approach to generate hyperpolarized metabolites within seconds, which act as metabolism probes. Hyperpolarization represents a magnetic resonance technique to enhance signals by over 10 000-fold. We accomplished an efficient metabolite hyperpolarization by developing an isotopic labeling strategy for generating precursors containing a favorable nuclear spin system to add para -hydrogen and convert its two-spin longitudinal order into enhanced metabolite signals. The transfer is performed by an invented NMR experiment and 20 000-fold signal enhancements are achieved. Our technique provides a fast way of generating hyperpolarized metabolites by using para -hydrogen directly in a high magnetic field without the need for field cycling.

Magnetic resonance imaging of mass transport and structure inside a phototrophic biofilm.

PubMed

Ramanan, Baheerathan; Holmes, William M; Sloan, William T; Phoenix, Vernon R

2013-05-01

The aim of this study was to utilize magnetic resonance imaging (MRI) to image structural heterogeneity and mass transport inside a biofilm which was too thick for photon based imaging. MRI was used to map water diffusion and image the transport of the paramagnetically tagged macromolecule, Gd-DTPA, inside a 2.5 mm thick cyanobacterial biofilm. The structural heterogeneity of the biofilm was imaged at resolutions down to 22 × 22 μm, enabling the impact of biofilm architecture on the mass transport of both water and Gd-DTPA to be investigated. Higher density areas of the biofilm correlated with areas exhibiting lower relative water diffusion coefficients and slower transport of Gd-DTPA, highlighting the impact of biofilm structure on mass transport phenomena. This approach has potential for shedding light on heterogeneous mass transport of a range of molecular mass molecules in biofilms.

Tunable Magnetic Resonance in Microwave Spintronics Devices

NASA Technical Reports Server (NTRS)

Chen, Yunpeng; Fan, Xin; Xie, Yunsong; Zhou, Yang; Wang, Tao; Wilson, Jeffrey D.; Simons, Rainee N.; Chui, Sui-Tat; Xiao, John Q.

2015-01-01

Magnetic resonance is one of the key properties of magnetic materials for the application of microwave spintronics devices. The conventional method for tuning magnetic resonance is to use an electromagnet, which provides very limited tuning range. Hence, the quest for enhancing the magnetic resonance tuning range without using an electromagnet has attracted tremendous attention. In this paper, we exploit the huge exchange coupling field between magnetic interlayers, which is on the order of 4000 Oe and also the high frequency modes of coupled oscillators to enhance the tuning range. Furthermore, we demonstrate a new scheme to control the magnetic resonance frequency. Moreover, we report a shift in the magnetic resonance frequency as high as 20 GHz in CoFe based tunable microwave spintronics devices, which is 10X higher than conventional methods.

Tunable Magnetic Resonance in Microwave Spintronics Devices

NASA Technical Reports Server (NTRS)

Chen, Yunpeng; Fan, Xin; Xie, Yungsong; Zhou, Yang; Wang, Tao; Wilson, Jeffrey D.; Simons, Rainee N.; Chui, Sui-Tat; Xiao, John Q.

2015-01-01

Magnetic resonance is one of the key properties of magnetic materials for the application of microwave spintronics devices. The conventional method for tuning magnetic resonance is to use an electromagnet, which provides very limited tuning range. Hence, the quest for enhancing the magnetic resonance tuning range without using an electromagnet has attracted tremendous attention. In this paper, we exploit the huge exchange coupling field between magnetic interlayers, which is on the order of 4000 Oe and also the high frequency modes of coupled oscillators to enhance the tuning range. Furthermore, we demonstrate a new scheme to control the magnetic resonance frequency. Moreover, we report a shift in the magnetic resonance frequency as high as 20 GHz in CoFe-based tunable microwave spintronics devices, which is 10X higher than conventional methods.

A simple polyol-free synthesis route to Gd2O3 nanoparticles for MRI applications: an experimental and theoretical study

NASA Astrophysics Data System (ADS)

Ahrén, Maria; Selegård, Linnéa; Söderlind, Fredrik; Linares, Mathieu; Kauczor, Joanna; Norman, Patrick; Käll, Per-Olov; Uvdal, Kajsa

2012-08-01

Chelated gadolinium ions, e.g., Gd-DTPA, are today used clinically as contrast agents for magnetic resonance imaging (MRI). An attractive alternative contrast agent is composed of gadolinium oxide nanoparticles as they have shown to provide enhanced contrast and, in principle, more straightforward molecular capping possibilities. In this study, we report a new, simple, and polyol-free way of synthesizing 4-5-nm-sized Gd2O3 nanoparticles at room temperature, with high stability and water solubility. The nanoparticles induce high-proton relaxivity compared to Gd-DTPA showing r 1 and r 2 values almost as high as those for free Gd3+ ions in water. The Gd2O3 nanoparticles are capped with acetate and carbonate groups, as shown with infrared spectroscopy, near-edge X-ray absorption spectroscopy, X-ray photoelectron spectroscopy and combined thermogravimetric and mass spectroscopy analysis. Interpretation of infrared spectroscopy data is corroborated by extensive quantum chemical calculations. This nanomaterial is easily prepared and has promising properties to function as a core in a future contrast agent for MRI.

Cartilage imaging in children: current indications, magnetic resonance imaging techniques, and imaging findings.

PubMed

Ho-Fung, Victor M; Jaramillo, Diego

2013-07-01

Evaluation of hyaline cartilage in pediatric patients requires in-depth understanding of normal physiologic changes in the developing skeleton. Magnetic resonance (MR) imaging is a powerful tool for morphologic and functional imaging of the cartilage. In this review article, current imaging indications for cartilage evaluation pertinent to the pediatric population are described. In particular, novel surgical techniques for cartilage repair and MR classification of cartilage injuries are summarized. The authors also provide a review of the normal anatomy and a concise description of the advances in quantitative cartilage imaging (ie, T2 mapping, delayed gadolinium-enhanced MR imaging of cartilage, and T1rho). Copyright © 2013 Elsevier Inc. All rights reserved.

Active extravasation of gadolinium-based contrast agent into the subdural space following lumbar puncture.

PubMed

Kothari, Pranay D; Hanser, Evelyn M; Wang, Harrison; Farid, Nikdokht

2016-01-01

A 38year-old male presented with cauda equina syndrome following multiple lumbar puncture attempts. Lumbar spine magnetic resonance imaging (MRI) showed a subdural hematoma and an area of apparent contrast enhancement in the spinal canal on sagittal post-contrast images. Axial post-contrast images obtained seven minutes later demonstrated an increase in size and change in shape of the region of apparent contrast enhancement, indicating active extravasation of the contrast agent. This is the first reported case of active extravasation of gadolinium-based contrast agent in the spine. Copyright © 2016 Elsevier Inc. All rights reserved.

Presence of Late Gadolinium Enhancement by Cardiac Magnetic Resonance Among Patients With Suspected Cardiac Sarcoidosis Is Associated With Adverse Cardiovascular Prognosis: A Systematic Review and Meta-Analysis.

PubMed

Hulten, Edward; Agarwal, Vikram; Cahill, Michael; Cole, Geoff; Vita, Tomas; Parrish, Scott; Bittencourt, Marcio Sommer; Murthy, Venkatesh L; Kwong, Raymond; Di Carli, Marcelo F; Blankstein, Ron

2016-09-01

Individuals with cardiac sarcoidosis have an increased risk of ventricular arrhythmia and death. Several small cohort studies have evaluated the ability of late gadolinium enhancement (LGE) by cardiac magnetic resonance imaging (MRI) to predict adverse cardiovascular events. However, studies have yielded inconsistent results, and some analyses were underpowered. Therefore, we sought to systematically review and perform meta-analysis of the prognostic value of cardiac MRI for patients with known or suspected cardiac sarcoidosis. We systematically searched for cohort studies of patients with known sarcoidosis with suspected cardiac involvement who underwent cardiac MRI with LGE with at least 12 months of either prospective or retrospective follow-up data regarding post-MRI adverse cardiovascular outcomes. We identified 7 studies of 694 subjects (mean age 53; 42% men).One hundred and ninety-nine patients (29%) were LGE positive. All-cause mortality occurred in 19 LGE-positive versus 17 LGE-negative subjects (annualized incidence, 3.1% versus 0.6%). The pooled relative risk was 3.38 (95% confidence interval, 1.07-10.7; P=0.04). Cardiovascular mortality occurred in 10 LGE-positive versus 2 LGE-negative subjects (annualized incidence, 1.9% versus 0.3%; relative risk 10.7 [95% confidence interval, 1.34-86.3]; P=0.03). Ventricular arrhythmia occurred in 41 LGE-positive versus 0 LGE-negative subjects (annualized incidence, 5.9% versus 0%; relative risk 19.5 [95% confidence interval, 2.68-143]; P=0.003). A combined end point of death or ventricular arrhythmia occurred in 64 LGE-positive versus 18 LGE-negative subjects (annualized incidence, 8.8% versus 0.6%; relative risk 6.20 [95% confidence interval, 2.47-15.6]; P<0.001). There was no significant heterogeneity for any outcomes. LGE is associated with future cardiovascular death and ventricular arrhythmia among patients referred to MRI for known or suspected cardiac sarcoidosis. © 2016 American Heart Association, Inc.

New Clathrin-Based Nanoplatforms for Magnetic Resonance Imaging

PubMed Central

Vitaliano, Gordana D.; Vitaliano, Franco; Rios, Jose D.; Renshaw, Perry F.; Teicher, Martin H.

2012-01-01

Background Magnetic Resonance Imaging (MRI) has high spatial resolution, but low sensitivity for visualization of molecular targets in the central nervous system (CNS). Our goal was to develop a new MRI method with the potential for non-invasive molecular brain imaging. We herein introduce new bio-nanotechnology approaches for designing CNS contrast media based on the ubiquitous clathrin cell protein. Methodology/Principal Findings The first approach utilizes three-legged clathrin triskelia modified to carry 81 gadolinium chelates. The second approach uses clathrin cages self-assembled from triskelia and designed to carry 432 gadolinium chelates. Clathrin triskelia and cages were characterized by size, structure, protein concentration, and chelate and gadolinium contents. Relaxivity was evaluated at 0.47 T. A series of studies were conducted to ascertain whether fluorescent-tagged clathrin nanoplatforms could cross the blood brain barriers (BBB) unaided following intranasal, intravenous, and intraperitoneal routes of administration. Clathrin nanoparticles can be constituted as triskelia (18.5 nm in size), and as cages assembled from them (55 nm). The mean chelate: clathrin heavy chain molar ratio was 27.04±4.8: 1 for triskelia, and 4.2±1.04: 1 for cages. Triskelia had ionic relaxivity of 16 mM−1s−1, and molecular relaxivity of 1,166 mM−1s−1, while cages had ionic relaxivity of 81 mM−1s−1 and molecular relaxivity of 31,512 mM−1s−1. Thus, cages exhibited 20 times higher ionic relaxivity and 8,000-fold greater molecular relaxivity than gadopentetate dimeglumine. Clathrin nanoplatforms modified with fluorescent tags were able to cross or bypass the BBB without enhancements following intravenous, intraperitoneal and intranasal administration in rats. Conclusions/Significance Use of clathrin triskelia and cages as carriers of CNS contrast media represents a new approach. This new biocompatible protein-based nanotechnology demonstrated suitable

Enhanced ferromagnetic resonance linewidth of the free layer in perpendicular magnetic tunnel junctions

NASA Astrophysics Data System (ADS)

Gopman, D. B.; Dennis, C. L.; McMichael, R. D.; Hao, X.; Wang, Z.; Wang, X.; Gan, H.; Zhou, Y.; Zhang, J.; Huai, Y.

2017-05-01

We report the frequency dependence of the ferromagnetic resonance linewidth of the free layer in magnetic tunnel junctions with all perpendicular-to-the-plane magnetized layers. While the magnetic-field-swept linewidth nominally shows a linear growth with frequency in agreement with Gilbert damping, an additional frequency-dependent linewidth broadening occurs that shows a strong asymmetry between the absorption spectra for increasing and decreasing external magnetic field. Inhomogeneous magnetic fields produced during reversal of the reference and pinned layer complex is demonstrated to be at the origin of the symmetry breaking and the linewidth enhancement. Consequentially, this linewidth enhancement provides indirect information on the magnetic coercivity of the reference and pinned layers. These results have important implications for the characterization of perpendicular magnetized magnetic random access memory bit cells.

Diagnostic and prognostic value of cardiovascular magnetic resonance in non-ischaemic cardiomyopathies

PubMed Central

2012-01-01

Cardiovascular Magnetic Resonance (CMR) is recognised as a valuable clinical tool which in a single scan setting can assess ventricular volumes and function, myocardial fibrosis, iron loading, flow quantification, tissue characterisation and myocardial perfusion imaging. The advent of CMR using extrinsic and intrinsic contrast-enhanced protocols for tissue characterisation have dramatically changed the non-invasive work-up of patients with suspected or known cardiomyopathy. Although the technique initially focused on the in vivo identification of myocardial necrosis through the late gadolinium enhancement (LGE) technique, recent work highlighted the ability of CMR to provide more detailed in vivo tissue characterisation to help establish a differential diagnosis of the underlying aetiology, to exclude an ischaemic substrate and to provide important prognostic markers. The potential application of CMR in the clinical approach of a patient with suspected non-ischaemic cardiomyopathy is discussed in this review. PMID:22857649

Multimodal targeted high relaxivity thermosensitive liposome for in vivo imaging

NASA Astrophysics Data System (ADS)

Kuijten, Maayke M. P.; Hannah Degeling, M.; Chen, John W.; Wojtkiewicz, Gregory; Waterman, Peter; Weissleder, Ralph; Azzi, Jamil; Nicolay, Klaas; Tannous, Bakhos A.

2015-11-01

Liposomes are spherical, self-closed structures formed by lipid bilayers that can encapsulate drugs and/or imaging agents in their hydrophilic core or within their membrane moiety, making them suitable delivery vehicles. We have synthesized a new liposome containing gadolinium-DOTA lipid bilayer, as a targeting multimodal molecular imaging agent for magnetic resonance and optical imaging. We showed that this liposome has a much higher molar relaxivities r1 and r2 compared to a more conventional liposome containing gadolinium-DTPA-BSA lipid. By incorporating both gadolinium and rhodamine in the lipid bilayer as well as biotin on its surface, we used this agent for multimodal imaging and targeting of tumors through the strong biotin-streptavidin interaction. Since this new liposome is thermosensitive, it can be used for ultrasound-mediated drug delivery at specific sites, such as tumors, and can be guided by magnetic resonance imaging.

Relative blood volume measurements by magnetic resonance imaging facilitate detection of testicular torsion.

PubMed

Cheng, H C; Khan, M A; Bogdanov, A; Kwong, K; Weissleder, R

1997-12-01

The authors determine the utility of relative blood volume measurements (rBV) using a blood pool marker for magnetic resonance imaging (MRI) in detection of early testicular torsion. Testicular torsion was induced in rats by counterclockwise 720 degrees rotation and fixation of the testis in the scrotum. MPEG-PL-DTPA-Gd enhanced MRI (30 mumol Gd/kg bolus injection) was performed 1 hour after torsion at 1.5 T using fat-suppressed three-dimensional fast spoiled gradient-recalled sequence for relative blood volume measurement and three-dimensional time-of-flight sequence for MR angiography (MRA). The rBV of the torqued testes was significantly lower (13.3% +/- 13.5%) than that of testes with sham operation (97.7% +/- 5.3%; P < 0.05). Rats with testicular torsion showed larger regions of ischemia than did animals with sham operation (63.4% +/- 13.0% versus 4.0% +/- 2.8% of all pixels in testis; P < 0.01). The MRA of testicular torsion showed engorgement of the distal testicular vein as a sign of venous compression or total disappearance of the testicular vein, indicating arterial insufficiency. The authors conclude that MPEG-PL-DTPA-Gd can be used to obtain functional (rBV), morphologic (tunica enhancement), and angiographic (venous engorgement, arterial compromise) findings that should improve the diagnosis of testicular torsion in the acute setting.