Institutional review board approved this study and informed consent was waived.
Inclusion criteria
- Fibrosis grade was confirmed pathologically using surgical resected specimen.
- The interval between MRI and operation was within 3 months.
Exclusion criteria
- More than 10 nodules in single patient.
- After preoperative portal vein embolization or transarterial chemo-embolizaion.
- Difficult to evaluate ADC or pathological liver fibrosis grade.
- Nodules at lateral segment (got strong influence from heart rate )
Patients
(patients)
104 patients with 115 area were evaluated.
Age: mean 66.4; Men: Female= 72: 32
(Contrast media)
Gd-EOB-DTPA 94 patients, Gd-DTPA 5 patients, SPIO 3 patients
Plain MRI 3 patients
(Underlying liver disease)
HBV:10,HCV:5
(Reason for operation)
Hepatocellular carcinoma:39 nodules
Cholangiocellular carcinoma: 3 nodules
Metastatic liver carcinoma : 79 nodules
⇒(primary : colon 51 nodules,
pancreas 2 nodules,
esophagus 2 nodules,
neuroendocrine tumor 2 nodules,
leiomyosarcoma 1 nodule,
mucinous adenocarcinoma 1 nodule,
GIST 1 nodule,
unknown 1 nodule)
Gallbladder carcinoma and polyp: 5 nodules
Others: 6 nodules
⇒(combined hepatocellular and cholangiocarcinoma,
inflammatory pseudo tumor,
hamartoma,
angiolipoma)
MRI protocol
1.5 T MRI system (Avanto; Siemens,
Erlangen,
German)
Maximum gradient strength: 45 mT/m,
32 channels coil
(DWI sequence)
TR/TE : 1500 / 66 msec,
Averages 6,
FOV 40cm,
Matrix 128×128,
Band width 2604 Hz,
Parallel Imaging Factor (GRAPPA) 2, slice thickness 5mm,
b factor; 100,
800 s/mm2,
Chemical shift selective fat suppression,
Acquisition time 3:22,
respiratory trigger method
(Gd-EOB-DTPA-enhanced MRI) (hepatobiliary phase)
TR/TE : 3.96/1.79 msec,
Averages 1,
FOV 40cm,
Matrix 320×70%,
Band width 460 Hz,
Parallel Imaging Factor (GRAPPA) 2,
slice thickness 2mm,Chemical shift selective fat suppression,
Acquisition time 19sec,
under breath-holding
Image processing
ADC value was obtained on ADC map.
1st ROI⇒Set at a distance of 5-10 mm from the tumor where fibrosis was assessed pathologically.
2nd ROI⇒Set on different segment in liver.
Liver-muscle ratio (LMR) was obtained at hepatobiliary phase in Gd-EOB-DTPA-enhanced MRI
3rd ROI⇒same location of 1st ROI
4th ROI⇒set on erector spinae
Liver-muscle ratio= 3rd ROI/4th ROI
Pathological evaluation
Two radiologists and one pathologist reviewed and discussed the MRI and the resected specimen,
and decided the point to evaluate fibrosis.
And fibrosis grade was evaluated at the distance of 5-10 mm to the tumor where was around the 1st and 3rd ROI set on MRI.
We used New Inuyama Classification to classify the fibrosis grade.
Statistic analysis
Correlation between F0-4 and ADC value
⇒Spearman's rank correlation coefficient
Difference of ADC value among F0-4
⇒Friedman test and Kruskal-Wallis test
Difference of ADC value between F0-2 and F3-4
⇒Mann-Whitney U test
Correlation coefficient = r
| r |≦0.15 : very weak correlation
0.15<| r |≦0.25 : weak correlation
0.25<| r |≦0.40 : moderate correlation
P <0.05 : significant difference