MR imaging of hepatocellular carcinoma: relationship between lesion size and imaging findings, including signal intensity and dynamic enhancement patterns.
OBJECTIVE
To assess the relationship between lesion size and MR imaging findings of pathologically-proven hepatocellular carcinoma (HCC).


METHODS
In a retrospective, single-center study, 37 consecutive patients were identified between 1999 and 2005 that underwent preoperative MRI and surgical resection of HCC. A total of 47 lesions (mean size = 6.85 cm, range = 1-25 cm) were assessed for signal intensity (SI), enhancement patterns, and secondary morphologic features. Interobserver rating, percentage enhancement, and contrast-to-noise-ratio (CNR) were determined. Lesions were assessed for combinations of typical MRI features. Regression analysis was used to assess relations between MRI findings and tumor size.


RESULTS
On fat-suppressed T2-weighted (T2w) fast-spin-echo, smaller lesions had lower SI compared to larger lesions (P < 0.05). In the arterial phase, smaller lesions showed significantly higher percentage enhancement compared to larger lesions (P < 0.05). In the delayed phase, smaller lesions showed less pronounced washout (P < 0.05). Heterogeneity of the lesions, including fatty infiltration, internal nodules, or mosaic pattern, was observed significantly more frequently in larger lesions (P < 0.001). The classic combination of high T2w signal, strong arterial enhancement, and delayed phase washout was present in 23 of 44 lesions (52%).


CONCLUSIONS
Smaller HCC often showed lower SI on T2w, more intense arterial enhancement, and less pronounced delayed washout compared to larger HCC.
van den Bos
Indra C
IC
Department of Radiology, University Medical Center Rotterdam, Rotterdam, The Netherlands. vandenbos.ic@gmail.com
Hussain
Shahid M
SM
Dwarkasing
Roy S
RS
Hop
Wim C J
WC
Zondervan
Pieter E
PE
de Man
Robert A
RA
IJzermans
Jan N M
JN
Walker
Craig W
CW
Krestin
Gabriel P
GP
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D006528:Carcinoma, Hepatocellular / Q000473:pathology* / Q000601:surgery; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008113:Liver Neoplasms / Q000473:pathology* / Q000601:surgery; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care; D012044:Regression Analysis; D012189:Retrospective Studies
D003287:Contrast Media; D019786:Gadolinium DTPA