Patients: A review of pathology and radiology records identified 29 patients with a diagnosis of IMC.
Each patient had undergone MRI examination at our facility during the period from June 2004 to June 2014. There were 19 men and 10 women,
with a mean age of 64 years (range 40-80 years).
No patient had a history of exposure to clonorchiasis or Thorotrast (thorium oxide).
Four patients had a history of liver cirrhosis (2 alcohol related; 2 cryptogenic).
No treatment for malignancy had been administered at the time of the MR imaging.
The diagnosis of IMC was established by means of histologic analysis (27 patients with surgical resection or percutaneous biopsy) or by the combination of typical MRI findings (rim enhancement on arterial phase with progressive filling on late phases) and laboratory studies (elevation of CA19.9).
Four patients did not undergo the 10-15-minutes phases and were excluded in some statistical analyses.
MR Technique: All examinations were performed with a 1.5-T superconducting unit.
All MR images were obtained in the axial plane with a field of view of 380 x 380 mm,
adjusted for each patient.
T1-weighted gradient-echo images (in- and out-phase) and breath-hold T2-weighted single-shot fast spin-echo images were obtained in all patients,
as well as T1- and T2-weighted fat-suppressed sequences.
We escluded DWI because we had it since 2010.
Dynamic MRI was done in all 29 patients using fat suppressed gradient-echo or 3D LAVA sequences,
as was the hepatobiliary phase at 2 hours.
After a set of unenhanced MRI images was obtained,
a bolus of 0.1 mmoL/Kg of Gd-BOPTA (Gadobenate Dimeglumine) was injected at a rate of 2 ml/sec,
followed by a 20 ml flush of normal saline using a power injector.
The scan delays for multiphasic dynamic imaging were 30,
40,
60,
180 and/or 300 seconds after contrast medium injection.
In one case (n.15),
we did not obtain portal and 3-5-minute late phases because of the patient’s discomfort after contrast medium injection.
In all patients but 4,
ulterior delayed phases of 10 and/or 15 minutes were obtained,
and in all patients the HBP phase was obtained 2-3 hours after the administration of contrast medium.
All MRI images were obtained in the axial plane with a phased array multicoil for the body centered over the liver.
Section thickness was 4-6 mm,
with a 2-3 mm intersection gap.
Image Interpretation: The MR images were retrospectively evaluated on a PACS console by two abdominal radiologists with experience in liver imaging (>10 years).
Individual reviews were done,
and discrepancies were resolved by consensus. In patients showing intrahepatic metastases,
the largest lesion was chosen for analysis.
The radiologists focused on the following features: size,
number,
location (right or left lobe),
shape (round-oval or irregular),
capsule,
T1 and T2 signal (comparable to adjacent liver parenchyma),
dynamic enhancement pattern and hepatospecific delayed pattern.
transient hepatic intensity difference (THID),
hepatic atrophy,
capsular retraction,
vascular infiltration,
biliary dilatation,
metastatic nodes,
and ascites were also evaluated.
The dynamic pattern of the lesions was described on a 5-point scale [0= only peripheral enhancement,
1= peripheral enhancement with associated dishomogeneous global enhancement,
2= progressive centripetal incomplete filling,
3= progressive dishomogeneous (no centripetal) incomplete filling,
and 4= complete or nearly complete enhancement].
In the 10-15-minute late phase,
we also evaluated signal intensity and homogeneity of the lesions,
and eventual presence of a hypointense peripheral rim.
A particular emphasis was placed on the hepatobiliary late phase pattern,
and the following features were evaluated: signal of lesions (cloud= persistent enhancement with a cloud-like signal intensity inside the lesion; defect= hypointensity due to wash-out of the lesion),
peripheral rim (No= absent,
Yes= present),
signal of the rim (Iso= isointensity,
Hypo= hypointensity,
Hyper= hyperintensity; c= continuous,
d= discontinuous).