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Optimization of single injection liver arterial phase gadolinium enhanced MRI using bolus track real‐time imaging
Author(s) -
Sharma Puneet,
Kalb Bobby,
Kitajima Hiroumi D.,
Salman Khalil N.,
Burrow Bobbie,
Ray Gaye L.,
Martin Diego R.
Publication year - 2011
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.22200
Subject(s) - bolus (digestion) , medicine , perfusion , gadolinium , reproducibility , nuclear medicine , aorta , magnetic resonance imaging , radiology , cardiology , materials science , mathematics , statistics , metallurgy
Purpose: To measure contrast agent enhancement kinetics in the liver and to further evaluate and develop an optimized gadolinium enhanced MRI using a single injection real‐time bolus‐tracking method for reproducible imaging of the transient arterial‐phase. Materials and Methods: A total of 18 subjects with hypervascular liver lesions were imaged with four dimensional (4D) perfusion scans to measure time‐to‐peak (TTP) delays of arterial (aorta‐celiac axis), liver parenchyma, liver lesion, portal, and hepatic veins. Time delays were calculated from the TTP‐aorta signal, and then related to the gradient echo (GRE) k‐space acquisition design, to determine optimized timing for real‐time bolus‐track triggering methodology. As another measure of significance, 200 clinical patients were imaged with 3D‐GRE using either a fixed time‐interval or by individualized arterial bolus real‐time triggering. Bolus TTP‐aorta was calculated and arterial‐phase acquisitions were compared for accuracy and reproducibility using specific vascular enhancement indicators. Results: The mean bolus transit‐time to peak‐lesion contrast was 8.1 ± 2.7 seconds following arterial detection, compared to 32.1 ± 5.4 seconds from contrast injection, representing a 62.1% reduction in the time‐variability among subjects ( N = 18). The real‐time bolus‐triggered technique more consistently captured the targeted arterial phase (94%), compared to the fixed timing technique (73%), representing an expected improvement of timing accuracy in 28% of patients ( P = 0.0001389). Conclusion: Our results show detailed timing window analysis required for optimized arterial real‐time bolus‐triggering acquisition of transient arterial phase features of liver lesions, with optimized arterial triggering expected to improve reproducibility in a significant number of patients. J. Magn. Reson. Imaging 2011;33:110–118. © 2010 Wiley‐Liss, Inc.