K. Takayasu et al., CT DIAGNOSIS OF EARLY HEPATOCELLULAR-CARCINOMA - SENSITIVITY, FINDINGS, AND CT-PATHOLOGICAL CORRELATION, American journal of roentgenology, 164(4), 1995, pp. 885-890
OBJECTIVE. The purpose of this study was to determine the sensitivity
of CT in detecting early hepatocellular carcinoma and to evaluate its
CT appearance. An early hepatocellular carcinoma is a nodular lesion w
ith no fibrous capsule composed of well-differentiated tumor histologi
cally. It differs from a small hepatocellular carcinoma, which is an o
vert tumor that is moderately to poorly differentiated and had a fibro
us capsule. Size is not a criterion for distinguishing between early a
nd small hepatocellular carcinomas. MATERIALS AND METHODS. Thirty-one
patients with 39 histopathologically proved early hepatocellular carci
nomas (mean diameter, 1.7 cm) found by sonography, MR imaging, and/or
intraoperative sonography were included in a retrospective study, We r
eviewed unenhanced CT scans of the entire liver in 30 patients (37 les
ions) and early and late (35 sec and 5 min after the beginning of inje
ction of contrast material) contrast-enhanced CT scans of the entire l
iver in all 31 patients (table incremental CT in 21; helical CT in 10;
39 lesions), Eighteen histologically proved small hepatocellular carc
inomas (less than or equal to 3 cm; mean diameter, 2.3 cm), present in
the same patients, served for comparison, Histopathologically, nine p
atients had chronic hepatitis, and 22 had cirrhosis. RESULTS. The over
all sensitivity of CT in detecting early hepatocellular carcinoma was
56%, These tumors were usually isodense with respect to surrounding li
ver on unenhanced, early enhanced, and late enhanced CT scans (iso-iso
-iso). This pattern was seen in 17(46%) of 37 lesions; thus, these 17
histologically proved early hepatocellular carcinomas were not detecte
d with CT, An iso-iso-low density pattern was recognized in eight (22%
), a low-low-law pattern in seven (19%), and several different pattern
s in five (13%) of the 37 lesions, Only two (5%) of 39 early hepatocel
lular carcinomas had a high-density appearance on early enhanced CT sc
ans, In comparison, the most common pattern of small overt hepatocellu
lar carcinomas on CT scans was low-high-low, seen in 17 lesions (94%)
detected with CT, When the density of lesions on unenhanced CT scans w
as compared with the histopathologic appearance of the masses, low-den
sity lesions showed mild to moderate fatty change and isodense lesions
showed no or minimal fatty change (p = .006). CONCLUSION. The sensiti
vity of CT in detecting early hepatocellular carcinoma is poor (56%),
However, the diagnosis of early hepatocellular carcinoma should be con
sidered if CT scans show a small lesion with an iso-low or low-low den
sity enhancement pattern on early and late contrast-enhanced CT scans,
respectively, in patients with chronic liver disease.