Effect of Gd‐DTPA‐BMA on blood and myocardial T₁ at 1.5T and 3T in humans

Abstract

Purpose: To compare T 1 values of blood and myocardium at 1.5T and 3T before and after administration of Gd-DTPA-BMA in normal volunteers, and to evaluate the distribution of contrast media between myocardium and blood during steady state. Materials and Methods:Ten normal subjects were imaged with either 0.1 mmol/kg (N ϭ 5) or 0.2 mmol/kg (N ϭ 5) of Gd-DTPA-BMA contrast agent at 1.5T and 3T. T 1 measurements of blood and myocardium were performed prior to contrast injection and every five minutes for 35 minutes following contrast injection at both field strengths. Measurements of biodistribution were calculated from the ratio of ⌬R 1 (⌬R 1myo /⌬R 1blood ).Results: Precontrast blood T 1 values (mean Ϯ SD, N ϭ 10) did not significantly differ between 1.5T and 3T (1.58 Ϯ .13 sec, and 1.66 Ϯ .06 sec, respectively; P Ͼ 0.05), but myocardium T 1 values were significantly different (1.07 Ϯ .03 sec and 1.22 Ϯ .07 sec, respectively; P Ͻ 0.05). The field-dependent difference in myocardium T 1 postinjection (T 1 @3T -T 1 @1.5T) decreased by approximately 72% relative to precontrast T 1 values, while the field-dependent difference of blood T 1 decreased only 30% postcontrast. Measurements of ⌬R 1myo /⌬R 1blood were constant for 35 minutes postcontrast, but changed between 1.5T and 3T (0.46 Ϯ .06 vs. 0.54 Ϯ .06, P Ͻ 0.10).Conclusion: T 1 is significantly longer for myocardium (but not blood) at 3T compared to 1.5T. The differences in T 1 due to field strength are reduced following contrast administration, which may be attributed to changes in ⌬R 1myo /⌬R 1blood with field strength.

Functional cardiac MR imaging with true fast imaging with steady-state free precession before and after intravenous injection of contrast medium: comparison of image quality and accuracy

“…We measured a strong and significant decrease in the T1 values of the myocardium and the blood after injection of contrast medium. These changes were in line with those detected by other observers [20]. Changes in T1 after injection of contrast medium cause a small but significant increase in signal intensity on true-FISP images.…”

Hyperpolarized Water as an MR Imaging Contrast Agent: Feasibility of in Vivo Imaging in a Rat Model

“…In figures 1-3, images are shown both directly from the spectrometer software (grayscale, spin-density images) and after a custom processing method that combines images with and without DNP to obtain phase information (combined color and grayscale, processed images). For the subcutaneous injection (Fig 1) the hyperpolarized water was observed traveling along the inlet tube and exiting through the incision, and because hyperpolarized water decays in approximately 5 seconds (based on the longevity of enhanced signal in comparable studies [24] and the T1 of blood [29]), we can conclude that water left the subcutaneous area within this time. The intraperitoneal images (Fig 2) show the injected water spreading…”

High resolution myocardial magnetic resonance stress perfusion imaging at 3 T using a 1 M contrast agent

“…Imaging techniques with strong T1-weighting which rely on the application of gadolinium-based contrast agents take particular advantage from an increase of field strength due to the prolongation of the longitudinal relaxation time at 3 T [12,13]. The result is a markedly improved contrast between unenhanced and contrast-enhanced tissue.…”

“…Working at 3 T offers the option to increase SNR and CNR because . c No signs of myocardial infarction (segments [13][14][15][16] gradient echo techniques using parallel imaging benefit most from high field MR imaging. The application of a more concentrated contrast agent allows a more compact bolus profile of the first pass, which also results in an increase of peak signal intensity and upslope of the signal intensity versus time curve [18].…”

“…Strongly T1-weighted sequence techniques relying on the application of paramagnetic contrast media particularly benefit from increased signal intensity at higher field strength [12,13]. Consequently, cardiac MR imaging including morphology, perfusion, and viability, takes advantage of 3-T high field conditions [14][15][16].…”