Detection of myocardial infarction in the mini‐pig using NMR imaging

Checkley, D.; Loveday, Bernard E.; Waterton, John C.; Zhu, Xiaoping; Isherwood, I.

doi:10.1002/mrm.1910050302

Cited by 22 publications

(5 citation statements)

References 22 publications

(6 reference statements)

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“…Myocardium is, however, usually not well delineated with sequences using long echo-times (1 1). Furthermore, T2 was not prolonged in early infarctions in mini-pigs and rabbits, suggesting species differences, which may be due to variations in collateral blood supply (3,7).…”

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confidence: 91%

Mr Imaging of Acute Myocardial Infarction in Pigs Using Gd-DTPA-Labeled Dextran

Wikström¹,

Martinussen²,

Wikström³

et al. 1992

Acta Radiol

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Myocardial infarctions were induced in 12 pigs. In 6 pigs, dextran-(Gd-DTPA)15 (~0 . 1 mmol Gdlkg b.w.) was injected i.v. 4 to 4.5 hours after coronary artery occlusion. ECG gated MR images were obtained repeatedly before (n =4) and after (n=6) contrast medium injection. Relaxation times in blood samples were measured repeatedly. The animals were sacrificed 2 hours after contrast medium administration. The hearts were excised, reexamined in the MR equipment and stained with triphenyltetrazolium chloride (TTC) in order to define areas of infarction. The remaining 6 pigs were sacrificed 6 hours after occlusion without administration of contrast medium. These hearts were only imaged ex vivo. In vivo, the infarctions could not be identified with or without dextran-(Gd-DTPA),,. Ex vivo, without contrast medium, the infarctions had an increased signal intensity, most pronounced in the T2-weighted images. Dextran-(Gd-DTPA),, caused a prolonged, pronounced shortening of TI and T2 in blood samples. The infarct demarcation improved in the TI-weighted images after injection of dextran-(Gd-DTPA),,, due to a moderate enhancement in normal myocardium and a stronger enhancement at the periphery of the infarctions, while the central parts of the infarctions were only weakly enhanced.

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mentioning

confidence: 91%

Mr Imaging of Acute Myocardial Infarction in Pigs Using Gd-DTPA-Labeled Dextran

Wikström¹,

Martinussen²,

Wikström³

et al. 1992

Acta Radiol

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“…Infarcted regions can be identified by local wall thinning, increased flow signal in the ventricular cavity, and increased signal intensity in the infarcted area [1][2][3][4][5]. In particular, T1 and T2 relaxation times are prolonged in the edematous infarct zone [7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 98%

“…Magnetic Resonance Imaging (MRI) of the heart offers the potential to noninvasively detect, localize and quantitate acutely infarcted myocardial areas [1][2][3][4][5][6][7][8][9][10][11]. Infarcted regions can be identified by local wall thinning, increased flow signal in the ventricular cavity, and increased signal intensity in the infarcted area [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Improved detection of acute myocardial infarction by magnetic resonance imaging using Gadolinium-DTPA

et al. 1989

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To assess the value of the paramagnetic contrast agent Gadolinium (Gd)-DTPA in Magnetic Resonance Imaging (MRI) of acute myocardial infarction (AMI), we studied 20 patients with a first AMI by ECG-gated MRI before and after intravenous administration of 0.15 mmol/kg Gd-DTPA. The MRI studies were performed after a mean of 98 hours (range 15-241) after the acute onset of AMI. Spin-echo measurements (TE 30 msec) were made using a Philips Gyroscan (0.5 Tesla). After performing the baseline MRI scans, the MRI procedure was repeated every 10 minutes for up to 40 minutes following injection of Gd-DTPA. In 18 (90%) patients contrast enhancement in the infarcted myocardial areas was observed after Gd-DTPA. In these patients intensity versus region curves, derived from 9 to 11 adjacent myocardial regions of interest, showed increased signal intensities in the infarcted areas after administration of Gd-DTPA. The precontrast signal intensity ratio between infarcted and normal myocardium was 1.14 +/- 0.15 (mean +/- SD); the postcontrast ratios at 10 minutes were 1.41 +/- 0.21 (P less than 0.05), at 20 minutes 1.61 +/- 0.19 (P less than 0.01), at 30 minutes 1.43 +/- 0.20 (P less than 0.05), and at 40 minutes 1.33 +/- 0.20 (P = NS). It is concluded that MRI using the contrast agent Gd-DTPA significantly improves the visualization and detection of infarcted myocardial areas in patients with AMI and that optimal contrast enhancement is obtained 20 minutes after administration of Gd-DTPA.

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“…It is therefore, mandatory to model these relaxation time changes due to CA interactions in order to quantify the CA concentration. In this study, a standard relaxometry technique for T 1 mapping [8] was implemented acquiring gradient-echo images with variable flip angles (VFA) with short TR. The VFA-based T 1 mapping was validated on a phantom with solutions of known T 1 values and provided T 1 value estimation with high accuracy and high spatial and temporal resolution.…”

Section: Introductionmentioning

confidence: 99%

Pharmacokinetic analysis and drug delivery efficiency of the focused ultrasound-induced blood-brain barrier opening in non-human primates

Samiotaki

Karakatsani

Buch

et al. 2017

Magnetic Resonance Imaging

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Purpose Focused Ultrasound (FUS) in conjunction with systemically administered microbubbles has been shown to open the Blood-Brain Barrier (BBB) locally, non-invasively and reversibly in rodents and non-human primates (NHP), suggesting the immense potential of this technique. The objective of this study entailed the investigation of the physiologic changes in the brain following the FUS-induced BBB opening and their relationship with the underlying anatomy. Materials and Methods Pharmacokinetic analysis was implemented in NHP’s that received FUS at various acoustic pressures. Relaxivity mapping enabled the robust quantitative detection of the BBB opening as well as gray and white matter segmentation. Drug delivery efficiency was measured for pre-clinical validation of the technique. Results Based on our results, the opening volume and the amount of the gadolinium delivered were found mostly contained in the grey matter, while FUS-induced permeability and drug concentration varied depending upon the underlying brain inhomogeneity, and increased with the acoustic pressure. Conclusions Overall, apart from the in vivo protocols for BBB analysis developed here, this study also suggests the important role that FUS can have in efficient drug delivery via localized and transient BBB opening.

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Detection of myocardial infarction in the mini‐pig using NMR imaging

Cited by 22 publications

References 22 publications

Mr Imaging of Acute Myocardial Infarction in Pigs Using Gd-DTPA-Labeled Dextran

Mr Imaging of Acute Myocardial Infarction in Pigs Using Gd-DTPA-Labeled Dextran

Improved detection of acute myocardial infarction by magnetic resonance imaging using Gadolinium-DTPA

Pharmacokinetic analysis and drug delivery efficiency of the focused ultrasound-induced blood-brain barrier opening in non-human primates

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