  Purpose: To develop and validate a multi-parametric SAturation-recovery
single-SHot Acquisition (mSASHA) cardiac T1 and T2 mapping technique with high
accuracy and precision in a single breath-hold.
  Methods: The mSASHA acquisition consists of 9 images in an 11 heartbeat
breath-hold -- the first without preparation, 6 images with saturation recovery
preparation, and 2 images with both saturation recovery and T2-preparation. T1
and T2 values were calculated using a 3-parameter model. mSASHA was validated
in simulations and phantoms on a Siemens 3T Prisma scanner with comparison to a
joint T1-T2 technique with a 4-parameter model. mSASHA values were compared to
reference MOLLI, SASHA and T2p-bSSFP sequences in 10 healthy volunteers.
  Results: mSASHA had high accuracy compared to reference spin-echo
measurements, with an average of -0.7+/-0.4% T1 error and -1.3+/-1.3% T2 error.
mSASHA coefficient of variation (CoV) in phantoms for T1 was lower than MOLLI
(0.7+/-0.1% vs 0.9+/-0.2%, p<0.01) and similar to reference T2p-bSSFP for T2
(1.4+/-0.6% vs 1.5+/-0.5%, p>0.05). In simulations, 3-parameter mSASHA fitting
had higher precision than 4-parameter joint T1-T2 fitting for both T1 and T2.
In-vivo myocardial mSASHA T1 was similar to conventional SASHA (1523+/-18 ms vs
1520+/-18 ms, p>0.05) with similar CoV to both MOLLI and SASHA (3.3+/-0.6% vs
3.1+/-0.6% and 3.3+/-0.5% respectively, p>0.05 for both). Myocardial mSASHA T2
values were 37.1+/-1.1 ms with similar precision to T2p-bSSFP (6.7+/-1.7% vs
6.0+/-1.6%, p>0.05).
  Conclusion: mSASHA provides high accuracy cardiac T1 and T2 quantification in
a single breath-hold, with similar precision to reference MOLLI and linear
T2p-bSSFP reference techniques.
