Threshold for enhancement in treated hepatocellular carcinoma on MDCT: Effect on necrosis quantification

Atilla Arslanoglu, Hamid Chalian, Faezeh Sodagari, Adeel R. Seyal, Höseyin Görkan Töre, Riad Salem, Vahid Yaghmai*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

OBJECTIVE. The objective of our study was to determine whether the conventionally used enhancement threshold of 10 HU for assessing tumor viability in treated hepatocellular carcinoma (HCC) lesions is valid. MATERIALS AND METHODS. To distinguish pseudoenhancement from enhancement in a tumor, we used an in vivo model: The attenuation of 54 hepatic cysts during the unenhanced and portal venous phases of MDCT, similar to what may be observed in HCC with central necrosis, was used to determine the threshold for pseudoenhancement. To validate this model, we compared the attenuation value of liver parenchyma in this cohort with that of 22 HCCs during the late arterial phase of enhancement. We tested the effect of this pseudoenhancement on quantifying necrosis in HCC compared with the conventionally used threshold of 10 HU. RESULTS. Values of enhancing HCC tissue on arterial phase MDCT (mean, 121.3 HU) were comparable with normal liver parenchyma on venous phase MDCT (117.3 HU) (p = 0.27). The threshold of 17.1 HU was the best threshold for the detection of pseudoenhancement in cysts (99% accuracy, 100% sensitivity, and 98% specificity). When this threshold was used instead of the conventional threshold of 10 HU, the mean necrosis proportion of treated HCC increased from 34.0% to 42.6% and the mean viable tumor proportion decreased from 66.0% to 57.4%. The quantification of viable HCC tissue based on 10 HU and the quantification of viable HCC tissue based on 17.1 HU were found to be significantly different (p < 0.0001). CONCLUSION. The threshold of 17.1 HU may be the appropriate cutoff for nonenhancement in a necrotic HCC. Use of this threshold may potentially affect how response to therapy is quantified and categorized.

Original languageEnglish (US)
Pages (from-to)536-543
Number of pages8
JournalAmerican Journal of Roentgenology
Volume206
Issue number3
DOIs
StatePublished - Mar 2016

Keywords

  • CT
  • Hepatocellular carcinoma
  • Modified Response Evaluation Criteria in Solid Tumors (mRECIST)
  • Necrosis
  • Viable

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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