Comparison of multislice breath-hold and 3D respiratory triggeredT1ρ imaging of liver in healthy volunteers and liver cirrhosis patients in 3.0 T MRI

Volumetric multicomponent T1ρ relaxation mapping of the human liver under free breathing at 3T

PURPOSE

To develop a 3D sequence for T_1ρ relaxation mapping using radial volumetric encoding (3D-T_1ρ -RAVE) and to evaluate the multi relaxation components in the liver of healthy controls and chronic liver disease (CLD) patients.

METHODS

Fat saturation and T_1ρ preparation modules were followed by a train of gradient-echo acquisitions and T₁ restoration delay. The series of T_1ρ -weighted images were fitted using mono-exponential, bi-exponential, and stretched-exponential models. The repeatability and reproducibility of the proposed technique were evaluated on National Institute of Standards and Technology phantom by calculating the coefficient of variation between test-retest scans on the same scanner and between two different 3T scanners, respectively. Mann-Whitney U-test was performed to assess differences in T_1ρ components among patients (n = 3) and a control group (n = 10).

RESULTS

The phantom study showed an error of 8.9% and 11.5% in mono T₂ relaxation time measurement relative to the reference on 2 different scanners. The coefficient of variation for test-retest scans performed on the same scanner was 5.7% and 2.4% for scans performed on 2 scanners. The comparison between healthy controls and CLD patients showed a significant difference (P < .05) in mono relaxation time (P = .002), stretched-exponential relaxation parameter (P = .04). The Akaike information criteria C criterion showed 2.53 ± 0.9% (2.3 ± 0.3% for CLD) of the voxels are bi-exponential while in 65.3 ± 5.8% (81.2 ± 0.06% for CLD) of the liver voxels, the stretched-exponential model was preferred.

CONCLUSION

The 3D-T_1ρ -RAVE sequence allows volumetric, multicomponent T_1ρ assessment of the liver during free breathing and can distinguish between healthy volunteers and CLD patients.

Combined morphological and functional liver MRI using spin-lattice relaxation in the rotating frame (T1ρ) in conjunction with Gadoxetic Acid-enhanced MRI

Noninvasive early detection of liver cirrhosis and fibrosis is essential for management and therapy. The aim was to investigated whether a combination of the functional parameter relative enhancement (RE) on Gadoxetic Acid magnetic resonance imaging (Gd-EOB-DTPA-enhanced MRI) and the fibrosis parameter T1ρ distinguishes cirrhosis and healthy liver. We analyzed patients with Gd-EOB-DTPA-enhanced MRI and T1ρ mapping. Signal intensity was measured before and after contrast; RE was calculated. T1ρ was measured with circular regions of interest (T1ρ-cROI). A quotient of RE and T1ρ-cROI was calculated: the fibrosis function quotient (FFQ). Cirrhosis was evaluated based on morphology and secondary changes. 213 datasets were included. The difference between cirrhotic and noncirrhotic liver was 51.11 ms vs. 47.56 ms for T1ρ-cROI (p < 0.001), 0.59 vs. 0.70 for RE (p < 0.001), and 89.53 vs. 70.83 for FFQ (p < 0.001). T1ρ-cROI correlated with RE, r = −0.14 (p < 0.05). RE had an AUC of 0.73. The largest AUC had the FFQ with 0.79. The best cutoff value was 48.34 ms for T1ρ-cROI, 0.70 for RE and 78.59 ms for FFQ. In conclusion T1ρ and RE can distinguish between cirrhotic and noncirrhotic liver. The FFQ, which is the combination of the two, improves diagnostic performance.

Breath-hold black-blood T1rho mapping improves liver T1rho quantification in healthy volunteers

Background Recent researches suggest that T1rho may be a non-invasive and quantitative technique for detecting and grading liver fibrosis. Purpose To compare a multi-breath-hold bright-blood fast gradient echo (GRE) imaging and a single breath-hold single-shot fast spin echo (FSE) imaging with black-blood effect for liver parenchyma T1rho measurement and to study liver physiological T1rho value in healthy volunteers. Material and Methods The institutional Ethics Committee approved this study. 28 healthy participants (18 men, 10 women; age = 29.6 ± 5.1 years) underwent GRE liver T1rho imaging, and 20 healthy participants (10 men, 10 women; age = 36.9 ± 10.3 years) underwent novel black-blood FSE liver T1rho imaging, both at 3T with spin-lock frequency of 500 Hz. The FSE technique allows simultaneous acquisition of four spin lock times (TSLs; 1 ms, 10 ms, 30 ms, 50msec) in 10 s. Results For FSE technique the intra-scan repeatability intraclass correlation coefficient (ICC) was 0.98; while the inter-scan reproducibility ICC was 0.82 which is better than GRE technique's 0.76. Liver T1rho value in women tended to have a higher value than T1rho values in men (FSE: 42.28 ± 4.06 ms for women and 39.13 ± 2.12 ms for men; GRE: 44.44 ± 1.62 ms for women and 42.36 ± 2.00 ms for men) and FSE technique showed liver T1rho value decreased slightly as age increased. Conclusion Single breath-hold black-blood FSE sequence has better scan-rescan reproducibility than multi-breath-hold bright-blood GRE sequence. Gender and age dependence of liver T1rho in healthy participants is observed, with young women tending to have a higher T1rho measurement.

Age- and Gender-Associated Liver Physiological T1rho Dynamics Demonstrated with a Clinically Applicable Single-Breathhold Acquisition

To understand women's and men's physiological ranges of liver T1rho relaxation time measured with a single breathhold black blood sequence, this healthy volunteer study was conducted in 62 women (mean age, 38.9 y; range, 18-75 y) and 34 men (mean age, 44.7 y; range, 24-80 y). Approval from the institutional ethics committee was obtained. Magnetic resonance imaging was performed with a 3.0T scanner with six spin-lock times of 0, 10, 20, 25, 35, and 50 ms and a single breathhold of 12 s per slice acquisition. Six slices were acquired for each examination. The results demonstrated that the female liver T1rho value ranged between 35.07 and 51.97 ms and showed an age-dependent decrease, with younger women having a higher measurement. The male liver T1rho value ranged between 34.94 and 43.39 ms, with no evidential age dependence. Postmenopausal women had similar liver T1rho values as men. For women, there was a trend that the liver T1rho value could be 4% to 5% lower during the menstrual phase than during the nonmenstrual phase. For both women and men, no evidential association was seen between body mass index and liver T1rho.

Quantitative assessment of liver function with whole-liver T1rho mapping at 3.0T

OBJECTIVES

To assess the segmental liver function in healthy subjects and liver cirrhosis (LC) patients with different Child-Pugh grades using whole-liver T1rho mapping at 3.0T.

METHODS

Thirty-three healthy volunteers and 33 patients with clinically diagnosed LC were examined using a three-dimensional (3D) whole-liver coverage T1rho mapping. T1rho maps were calculated from five respiratory-triggered sequences with different spin-lock durations (0, 10, 20, 40, and 60ms). The patients were classified into group A with Child-Pugh A cirrhosis and group B with Child-Pugh B or C cirrhosis. The hepatic T1rho values in different segments of the healthy volunteers and LC patients were compared, and receiver operating characteristic curves (ROC) were plotted to determine the performance of T1rho.

RESULTS

The median T1rho value of the patients (Child-Pugh class A: 47.07ms; Child-Pugh classes B and C: 51.09ms) was significantly higher than that of the healthy volunteers (39.37ms, P<0.001). No remarkable variations among different hepatic segments in LC patients with various Child-Pugh grades were found (P>0.05). The T1rho values of the liver parenchyma were significantly correlated with albumin (r=-0.590, P<0.001) and prothrombin time (r=0.601, P<0.001). The T1rho values in patients increased with an increase in the Child-Pugh classification (r=0.574, P<0.001).

CONCLUSIONS

The whole-liver coverage T1rho sequence at 3.0T was feasible for the assessment of segmental liver function. T1rho relaxation might be a potential biomarker for the estimation of liver function in LC patients.