Ursula Reiter, Presenter: Nothing to Disclose

Gert Reiter, Abstract Co-Author: Employee, Siemens AG

Katrin Dorr MD, Abstract Co-Author: Nothing to Disclose

Andreas Greiser PhD, Abstract Co-Author: Employee, Siemens AG

Ralph Maderthaner MD, Abstract Co-Author: Nothing to Disclose

Michael Herbert Fuchsjaeger MD, Abstract Co-Author: Nothing to Disclose

To evaluate regional differences between systolic and diastolic myocardial longitudinal relaxation time (T1), and to investigate variances of myocardial T1 values associated with T1 time of blood to derive relations between blood normalized systolic and diastolic myocardial T1 times in healthy subjects.

In the current prospective study, approved by the local ethical review board, 40 healthy subjects (20 female, 20 male; age range 20-35 years) underwent ECG-gated 1.5 T magnetic resonance imaging. A modified Look-Locker inversion recovery (MOLLI) sequence was used to acquire basal, mid-ventricular and apical short-axis myocardial T1 maps in systole and diastole. Regional myocardial T1 times were evaluated in 16 AHA-segments, blood T1 values were derived from blood pool in the center of the left ventricular cavity. Linear regression slopes between myocardial and blood T1 values were employed to normalize measured myocardial T1 values to the mean blood T1 time of the study population. Means of T1 values were compared by t-test, considering p < 0.05 as significant.

Mean myocardial T1 times (984 ± 28 ms in diastole, 959 ± 21 ms in systole) as well as all segmental T1 values in diastole and systole differed significantly (p<0.001 for all comparisons). Blood T1 times correlated well with segmental myocardial T1 values (R2 = 0.53 for diastole, R2 = 0.52 for systole): After blood normalization variances of segmental and mean myocardial T1 times decreased (to 17 ms in diastole and 13 ms in systole in case of mean myocardial T1 times) and significant differences in segmental and mean myocardial T1 times with gender completely disappeared. Blood normalized diastolic and systolic myocardial T1 values strongly correlated with each other on segmental (r = 0.72) as well as mean myocardial (r = 0.89) level.

In normal myocardium, diastolic and systolic myocardial T1 times significantly differ but strongly correlate with each other. Besides elimination of gender differences in myocardial T1 values, blood normalization reduces variability of myocardial T1 times.

Blood normalization allows improving the definition of threshold values to distinguish normal from pathologically affected myocardium in diastole and systole.

Reiter, U, Reiter, G, Dorr, K, Greiser, A, Maderthaner, R, Fuchsjaeger, M, Normal Diastolic and Systolic Myocardial T1 Times at 1.5 T: Correlations and Blood Normalization.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13021740.html