Gd‐enhanced MR images of substrates other than water

Terreno, Enzo; Botta, Maurizio; Dastrù, Walter; Aime, Silvio

doi:10.1002/cmmi.94

Cited by 14 publications

(12 citation statements)

References 18 publications

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“…As Gd 3+ and other lanthanides prefer eight to nine coordinate structures (17), chelation with EDTA occupies only six of these coordination sites, increasing the likelihood of inner‐sphere relaxation effects and therefore the measured relaxivity. As has been shown with Gd‐DO3A, heptadentate contrast agents with an inner‐sphere relaxation mechanism can greatly enhance the relaxation rate of carbon nuclei (18, 19). Furthermore, charge of the chelate plays a role in relaxivity, as increasing negative charge will increase the distance of closest approach between the two anionic species, also leading to a lower relaxivity (20, 21).…”

Section: Discussionmentioning

confidence: 85%

Gemcitabine‐based doublets versus single‐agent therapy for elderly patients with advanced nonsmall cell lung cancer

Russo

Rizzo

Fulfaro

et al. 2009

Cancer

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BACKGROUND:Although platinum‐based combinations are considered the best option of care for patients with advanced nonsmall cell lung cancer (NSCLC), single‐agent therapy is the preferred treatment for older patients. Since the late 1990s, various combinations of third‐generation agents (gemcitabine [G], vinorelbine, docetaxel, and paclitaxel) have been tested, yielding contradictory results. The authors of this report performed a literature‐based meta‐analysis to assess the efficacy and tolerability of G‐based doublets compared with single‐agent chemotherapy for elderly patients with NSCLC.METHODS:Data from all published, randomized, phase 3 trials that compared a G‐based doublet with a third‐generation single agent in elderly patients were collected from electronic databases (Medline and the Cochrane Central Register of Controlled Trials), relevant reference lists, and abstract books. Pooled odds ratios (ORs) were calculated for the 1‐year survival rate, the overall response rate (ORR), and grade 3 and 4 toxicities.RESULTS:Four eligible trials (1436 patients) were selected from 442 studies that initially were identified. A significant difference in ORR favoring G‐based doublets over single agents was observed (OR, 0.65; 95% confidence interval [95% CI], 0.51‐0.82 [P < .001]), whereas the trend toward an improved 1‐year survival rate was not significant (OR, 0.78; 95% CI, 0.57‐1.06 [P = .169]). Grade 3 and 4 toxicities did not differ significantly except for thrombocytopenia (OR, 1.76; 95% CI, 1.12‐2.76 [P = .014]).CONCLUSIONS:G‐based doublets appeared to be effective and feasible compared with single agents in the treatment of elderly patients with advanced NSCLC who were not suitable for full‐dose, platinum‐based chemotherapy. Further prospective, elderly specific, phase 3 trials will be necessary. Cancer 2009. © 2009 American Cancer Society.

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Section: Discussionmentioning

confidence: 85%

Gemcitabine‐based doublets versus single‐agent therapy for elderly patients with advanced nonsmall cell lung cancer

Russo

Rizzo

Fulfaro

et al. 2009

Cancer

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“…This has largely concentrated on enhancing the relaxivity of protons in water, the dominant mechanism being due to direct inner-sphere coordination. However outer-sphere mechanisms are also known to play an important role and Gd-based contrast agents have been shown to enhance the relaxation of substrates other than water (7), and for a range of other nuclei such as 13 C, 31 P, 19 F and 6 Li (8,9). It has been suggested that contrast agents might be combined with hyperpolarization techniques to modulate the lifetime of the hyperpolarized signal (9).…”

Section: Introductionmentioning

confidence: 98%

Modulating the relaxivity of hyperpolarized substrates with gadolinium contrast agents

Gabellieri

Leach

Eykyn

2009

Contrast Media & Molecular

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Gadolinium contrast agents are known to affect the outer-sphere relaxivities of nuclei other than protons. We have investigated the heteronuclear relaxivities of four commercial gadolinium contrast agents (Magnevist, Omniscan, Dotarem and Gadovist) on the relaxation of (13)C in glycine, (13)C in pyruvate and (15)N in choline with long relaxation times. Marked differences in the relaxivities were found between different contrast agents and are attributed to electrostatic effects. This methodology may find applications in the field of hyperpolarized magnetic resonance and by way of example we show that injection of a bolus of contrast agent into an aqueous solution containing hyperpolarized (15)N labeled tetramethylammonium or (13)C labeled pyruvate leads to a predictable shortening of the lifetime of the hyperpolarized signal.

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“…Applications of these contrast agents range from the detection of multiple sclerosis [9] to the visualization of brain tumors [10] and tracking of individual cells in vivo [11]. However, the effect of contrast agents on the relaxation rate of X nuclei is less well known; in fact, we are only aware of a few studies [4,12] none of which reported relaxivity as such.…”

Section: Introductionmentioning

confidence: 99%

Relaxivity of Gd-based contrast agents on X nuclei with long intrinsic relaxation times in aqueous solutions

Heeswijk¹,

Laus²,

Morgenthaler³

et al. 2007

Magnetic Resonance Imaging

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The relaxivity of commercially available gadolinium (Gd)-based contrast agents was studied for X-nuclei resonances with long intrinsic relaxation times ranging from 6 s to several hundred seconds. Omniscan in pure 13 C formic acid had a relaxivity of 2.9 mM À1 s À1, whereas its relaxivity on glutamate C1 and C5 in aqueous solution was~0.5 mM À1 s À1 . Both relaxivities allow the preparation of solutions with a predetermined short T 1 and suggest that in vitro substantial sensitivity gains in their measurement can be achieved. 6 Li has a long intrinsic relaxation time, on the order of several minutes, which was strongly affected by the contrast agents. Relaxivity ranged from~0.1 mM À1 s À1 for Omniscan to 0.3 for Magnevist, whereas the relaxivity of Gd-DOTP was at 11 mM À1 s À1 , which is two orders of magnitude higher. Overall, these experiments suggest that the presence of 0.1-to 10-AM contrast agents should be detectable, provided sufficient sensitivity is available, such as that afforded by hyperpolarization, recently introduced to in vivo imaging. D

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Gd‐enhanced MR images of substrates other than water

Cited by 14 publications

References 18 publications

Gemcitabine‐based doublets versus single‐agent therapy for elderly patients with advanced nonsmall cell lung cancer

Gemcitabine‐based doublets versus single‐agent therapy for elderly patients with advanced nonsmall cell lung cancer

Modulating the relaxivity of hyperpolarized substrates with gadolinium contrast agents

Relaxivity of Gd-based contrast agents on X nuclei with long intrinsic relaxation times in aqueous solutions

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