+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Assessment of diffuse myocardial fibrosis in rats using small-animal Look-Locker inversion recovery T1 mapping



Assessment of diffuse myocardial fibrosis in rats using small-animal Look-Locker inversion recovery T1 mapping



Circulation. Cardiovascular Imaging 4(6): 636-640



The concentration of gadopentetate dimeglumine in myocardium and blood can be assessed from T1 measurements and can be used to calculate the extracellular volume (ECV) of the myocardium. We hypothesized that diffuse myocardial fibrosis in a small-animal model could be quantitatively assessed by measuring myocardial ECV using small-animal Look-Locker inversion recovery T1 mapping. Sprague-Dawley rats (n=10) were subjected to continuous angiotensin-2 (AT2) infusion for 2 weeks via a subcutaneously implanted minipump system. Magnetic resonance imaging (MRI) was performed both before and after AT2 infusion. The MRI protocol included multislice cine imaging and before-and-after contrast small-animal Look-Locker inversion recovery T1 mapping and late gadolinium enhancement imaging. Myocardial ECV was calculated from hematocrit and T1 values of blood and myocardium. During the course of AT2 infusion, the mean±SD systolic blood pressure increased from 122±10.9 to 152±27.5 mm Hg (P=0.003). Normalized heart weight was significantly higher in AT2-treated animals than in control littermates (P=0.033). Cine MRI documented concentric left ventricular hypertrophy. Postcontrast myocardial T1 times were shortened after treatment (median [interquartile range], 712 [63] versus 820 [131] ms; P=0.002). Myocardial ECV increased from 17.2% (4.3%) before to 23.0% (6.2%) after AT2 treatment (P=0.031), which was accompanied by perivascular fibrosis and microscarring on myocardial histological analysis. There was a moderate level of correlation between ECV and collagen volume fraction, as assessed by histological analysis (r=0.69, P=0.013). In a small-animal model of left ventricular hypertrophy, contrast-enhanced T1 mapping can be used to detect diffuse myocardial fibrosis by quantification of myocardial ECV.

Please choose payment method:






(PDF emailed within 0-6 h: $19.90)

Accession: 036259676

Download citation: RISBibTeXText

PMID: 21917782

DOI: 10.1161/circimaging.111.966796


Related references

Assessment of cardiac function and myocardial morphology using small animal Look-Locker inversion recovery (SALLI) MRI in rats. Journal of Visualized Experiments 2013(77):, 2013

Small animal Look-Locker inversion recovery (SALLI) for simultaneous generation of cardiac T1 maps and cine and inversion recovery-prepared images at high heart rates: initial experience. Radiology 261(1): 258-265, 2011

Histological Validation of measurement of diffuse interstitial myocardial fibrosis by myocardial extravascular volume fraction from Modified Look-Locker imaging (MOLLI) T1 mapping at 3 T. Journal of Cardiovascular Magnetic Resonance 17: 48, 2015

Shortened Modified Look-Locker Inversion recovery (ShMOLLI) for clinical myocardial T1-mapping at 1.5 and 3 T within a 9 heartbeat breathhold. Journal of Cardiovascular Magnetic Resonance 12: 69, 2010

Accuracy, precision, and reproducibility of myocardial T1 mapping: A comparison of four T1 estimation algorithms for modified look-locker inversion recovery (MOLLI). Magnetic Resonance in Medicine 78(5): 1746-1756, 2017

Modified look-locker inversion recovery T1 mapping indices: assessment of accuracy and reproducibility between magnetic resonance scanners. Journal of Cardiovascular Magnetic Resonance 15: 64, 2013

Quantitative assessment of hepatic function: modified look-locker inversion recovery (MOLLI) sequence for T1 mapping on Gd-EOB-DTPA-enhanced liver MR imaging. European Radiology 26(6): 1775-1782, 2016

Inversion group (IG) fitting: A new T1 mapping method for modified look-locker inversion recovery (MOLLI) that allows arbitrary inversion groupings and rest periods (including no rest period). Magnetic Resonance in Medicine 75(6): 2332-2340, 2016

Modified Look-Locker inversion recovery (MOLLI) for high-resolution T1 mapping of the heart. Magnetic Resonance in Medicine 52(1): 141-146, 2004

Consideration of slice profiles in inversion recovery Look-Locker relaxation parameter mapping. Magnetic Resonance Imaging 32(8): 1021-1030, 2014

Selection of magnetization catalyzation and readout methods for modified Look-Locker inversion recovery: a T1 mapping primer. Magnetic Resonance Imaging 33(4): 363-373, 2015

Automated brain tissue segmentation based on fractional signal mapping from inversion recovery Look-Locker acquisition. Neuroimage 52(4): 1347-1354, 2010

Endogenous assessment of diffuse myocardial fibrosis in patients with T 1ρ -mapping. Journal of Magnetic Resonance Imaging 45(1): 132-138, 2017

Fast T1 mapping determined using incomplete inversion recovery look-locker 3D balanced SSFP acquisition and a simple two-parameter model fit. Journal of Magnetic Resonance Imaging 35(6): 1437-1444, 2012

Optimization and validation of a fully-integrated pulse sequence for modified look-locker inversion-recovery (MOLLI) T1 mapping of the heart. Journal of Magnetic Resonance Imaging 26(4): 1081-1086, 2007