Keywords:
Abdomen, MR-Diffusion/Perfusion, MR, Diagnostic procedure, Imaging sequences, Cirrhosis, Liver
Authors:
R. Girometti, D. Bagatto, G. Esposito, L. Cereser, M. Bazzocchi, C. Zuiani; Udine/IT
DOI:
10.1594/ecr2011/C-1430
Results
Consistency of measurements
Despite the presence of outliers,
no significant difference was observed by comparing liver ADC (Tab.
2) and perfusion fraction f (Tab.
3) of the plane 1 vs.
that of the plane 2,
both in controls and cirrhotics (p>0.01;unpaired t-test).
These results were obtained regardless of the motion-probing gradient direction that has been applied.
It is arguable that the methodology of ADC measurement and the use of ultra-high field strength provided consistent results throughout the liver in our model.
ADC and within controls and cirrhotic patients
Along each gradient direction,
liver ADC significantly decreased by increasing the maximum b-value from 400 to 800 sec/mm2 (p<0.01;paired t-test),
both in controls and cirrhotic patients (Tab.
4-5). (Note that the set with b=800 sec/mm2 was assumed to represent the true Diffusion D.) Exceptions occurred in cirrhotic patients,
along the y direction,
both at planes 1 and 2,
with a nearly statistical significant difference (p=0.0288 and 0.0111,
respectively).
However,
ADC decrease was larger in controls than in cirrhotics,
showing a mean of 0.57 (at the plane 1) and 0.54 (at the plane 2) x 10-3 mm2/sec vs.
0.17 (at the plane 1) and 0.26 (at the plane 2) x 10-3 mm2/sec (Tab.
4-5).
Diagnosis of cirrhosis and volume fraction f
As expected,
liver ADC was found lower in cirrhotic patients as compared to controls,
regardless of the maximum b-value,
gradient direction and plane of measurement (Tab.
6).
The difference in ADC was significant in all cases (p<0.01; unpaired t-test),
except along the x (p=0.0139) and y (p=0.0174) directions at the plane 1,
by using the maximum b = 800 sec/mm2.
Also the perfusion fraction f was found lower in cirrhotic patients as compared to controls,
regardless of the gradient direction and plane of measurement (Tab.
7).
The difference was statistically significant (p<0.01; unpaired t-test),
except along the x direction (p=0.0106) at the plane 1 x and z directions at the plane 2 (p=0.0553 and 0.0235,
respectively).