Characterization of cardiac masses with T1 mapping
Journal of Cardiovascular Magnetic Resonance volume 17, Article number: Q32 (2015)
We hypothesize that T1 mapping contributes to the characterization of cardiac masses based on the spectrum of T1 relaxation times in tissue consisting of fat, calcium, melanin, blood and simple fluid. Given the well-established T1 lowering properties of melanin, T1mapping may assist in the evaluation of cardiac masses in patients with melanoma. Differentiating common cardiac tumors, such as myxomas, from thrombi with T1 mapping would also provide clinical utility, particularly in patients with a contraindication to gadolinium.
We analyzed all CMR studies between January 2011 and April 2014 referred to our center for mass evaluation in patients with known metastatic melanoma, known or suspected thrombus, myxoma, lipoma, simple cyst and mitral annular calcification who underwent a modified look locker inversion recovery (MOLLI) T1 mapping sequence at 1.5T. We excluded 3 cases due to small mass size and poor differentiation of the mass from surrounding tissue. In the final analysis, we included 35 CMR examinations from 30 individual patients. More than one T1 measurement was performed in patients with multiple masses or for individual masses with T1 inhomogeneity. A total of 46 measurements were performed and averaged according to mass type. Melanomas were further subtyped as melanin-rich (T1 < 1000 ms) or melanin-poor (T1 >1000 ms).
Fat-based masses, melanin-rich melanomas and mitral annular calcification showed relatively short T1 times (Table and Figure). Conversely, thrombi and myxomas showed intermediate and relatively long T1 times, respectively, and the simple pericardial cyst showed the longest T1 time (Table and Figure).
T1 mapping of masses may assist in tissue characterization, particularly in melanin-rich melanomas, myxomas and thrombi.
This work was funded by the Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, USA.
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Saba, S.G., Bandettini, P.W., Shanbhag, S.M. et al. Characterization of cardiac masses with T1 mapping. J Cardiovasc Magn Reson 17 (Suppl 1), Q32 (2015). https://doi.org/10.1186/1532-429X-17-S1-Q32