Assessment of tumor necrosis of hepatocellular carcinoma after chemoembolization: diffusion-weighted and contrast-enhanced MRI with histopathologic correlation of the explanted liver.
OBJECTIVE
The purpose of this study was to compare, with histopathologic examination of the liver explant as the reference standard, diffusion-weighted MRI with contrast-enhanced subtraction MRI in the assessment of necrosis of hepatocellular carcinoma (HCC) after trans arterial chemoembolization (TACE).


METHODS
The cases of 21 patients with HCC who underwent MRI after TACE were evaluated. Two independent observers calculated the apparent diffusion coefficient (ADC) of HCC and measured percentage tumor necrosis on subtraction images. The ADCs of necrotic and viable tumor tissues were compared. ADC and percentage necrosis on subtraction images were correlated with percentage necrosis found at pathologic examination. Receiver operating characteristics analysis was performed on the diagnosis of complete tumor necrosis.


RESULTS
Twenty-eight HCCs (mean diameter, 2.3 cm) were evaluated. There were significant differences between the ADC of viable tissue and that of necrotic tumor tissue (1.33 +/- 0.41 vs 2.04 +/- 0.38 x 10(-3) mm(2)/s, p < 0.0001). There was significant moderate correlation between ADC and the pathologic finding of percentage necrosis (r = 0.64, p < 0.001) and significant strong correlation between subtraction image and pathologic percentage necrosis (r = 0.89-0.91, depending on the phase; p < 0.001). In the diagnosis of complete tumor necrosis, ADC had an area under the curve, sensitivity, and specificity of 0.85, 75%, and 87.5% compared with 0.82-0.89, 100%, and 58.3-79.1% for subtraction imaging (p > 0.5 between ADC and subtraction imaging).


CONCLUSIONS
Compared with diffusion-weighted imaging, contrast-enhanced MRI with subtraction technique had more significant correlation with the histopathologic findings in the evaluation of necrosis of HCC after TACE. There was no difference, however, between the two methods in diagnosis of complete tumor necrosis.
Mannelli
Lorenzo
L
Department of Radiology, MRI, New York University Medical Center, New York, NY 10016, USA.
Kim
Sooah
S
Hajdu
Cristina H
CH
Babb
James S
JS
Clark
Timothy W I
TW
Taouli
Bachir
B
D000180:Acrylic Resins / Q000008:administration & dosage*; D000903:Antibiotics, Antineoplastic / Q000008:administration & dosage; D001706:Biopsy; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy* / Q000473:pathology*; D016461:Chemoembolization, Therapeutic / Q000379:methods*; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D004317:Doxorubicin / Q000008:administration & dosage*; D005780:Gelatin / Q000008:administration & dosage*; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000473:pathology*; D011379:Prognosis; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D016896:Treatment Outcome
D000180:Acrylic Resins; D000903:Antibiotics, Antineoplastic; D003287:Contrast Media; C496735:trisacryl gelatin microspheres; D004317:Doxorubicin; D005780:Gelatin