Objective:

To evaluate the quantitative characteristics of T1 values of left and right lobes obtained by two kinds of T1 mapping methods (free-breathing Look-locker sequence and breath-holding B1-corrected VFA sequence)

and to evaluate their variability.

Methods:

Seventy patients with liver disease were enrolled in Affiliated Cancer Hospital of Zhengzhou University Henan Cancer Hospital (both free-breathing Look-locker sequences and breath-holding B1-corrected VFA sequence scans). Four patients were excluded because of the inability to cooperate with the breath. The final 66 patients were included in the study. The T1 values of the Look-locker sequence and breath-hold B1-corrected VFA sequence in the left and right lobes of the liver were measured in 66 patients

and the differences in T1 values obtained from the two imaging methods were compared. The coefficient of variation (CV) of T1 values was compared to evaluate the reliability of these two sequences. Bland-Altman method was used to compare the measurement results between physician 1 and physician 2.

Results:

The correlation coefficients of the T1 value in left lobe was 0.961 in Look-locker and 0.884 in B1-corrected VFA respectively

and it in right lobe was 0.962 and 0.828

respectively (

P

0.001). It is no significant difference between cirrhosis and non-cirrhosis in Look-locker and B1-corrected VFA of left and right lobe of liver (

P

0.05). Compared the T1 values ［(803.3980.59)10

-3

s

(777.5384.97)10

-3

s］ obtained from the Look-locker sequencein the left and right lobes of the liver with the T1 values obtained from the B1-corrected VFA sequence ［(869.77116.67) 10

-3

s

(852.08125.03)10

-3

s］. The difference was not statistically significant (

P

0.05;

t

=1.794

0.840). There was a statistically significant difference between the two sequences in the T1 values obtained from the left and r

ight lobes of the liver (

P

0.05

t

=14.63

15.48). The coefficient of variation of the left and right lobe of liver in Look-locker (0.100

0.109) was significantly lower than in B1-corrected VFA T1 mapping (0.134

0.147). The Bland-Altman scatter plot shows that the distribution of f values determined by the Look-locker sequence is relatively more concentrated.

Conclusion:

The T1 values obtained by using the Look-locker sequence and the B1-corrected VFA sequence for normal liver tissues are different. The change in the T1 value does not indicate liver cirrhosis. The consistency of the T1 value measured by the Look-locker sequence is assessed to be small. The image quality is more stable

and the clinical practical value is higher..