Significant Factor Indicates Need for CTHA in Addition to Dynamic CT

Dynamic CT studies are a typical part of the preoperative evaluation of the hypervascularity of hepatocellular carcinoma (HCC), but certain patients may benefit from the addition of computed tomography during hepatic arteriography (CTHA). Researchers reported their findings in Cardiovascular and Interventional Radiology.

Although CTHA is more sensitive than other types of imaging for identifying hypervascular HCC, reports in the literature, as well as concerns about cost and invasiveness, have led to a recommendation that CTHA only be performed under specific circumstances.

To better understand proper indications for CTHA, researchers conducted a retrospective study in 45 patients with 60 pathologically confirmed HCCs who underwent both dynamic CT (dCT) and CTHA. The patients were categorized into 2 groups, which were based on the number of hypervascular HCCs identified on dCT and CTHA studies.

Patients in group A had the same number of HCCs detected through dCT and through CTHA, suggesting that the addition of CTHA was not necessary. Among patients in group B, there were fewer HCCs detected by dCT than on CTHA, which meant that CTHA had been helpful.

Next, the researchers evaluated factors in the 2 groups to determine which ones might be indicative of a need for CTHA. Patient characteristics, the serum alpha-fetoprotein level, and the tumor-liver contrast (TLC) of the main tumor on dCT scans of both groups were compared, and univariate logistic regression analysis was performed.

Only one factor—tumor-liver contrast (TLC)—was found to be a significant indicator of the need for CTHA. The optimal cutoff value for the TLC of the main tumor on dCT images was 15.9 Hounsfield units. The sensitivity for the benefit of CTHA was 85%, and the specificity was 92%.

“In conclusion, the TLC of the main tumor on preoperative dCT images was a significant factor alerting to the benefit of additive CTHA studies, suggesting that in patients with a TLC value of the main tumor on preoperative dCT images below 15.9 HU, the evaluation on additive CTHA scans is beneficial to establish the accurate number of hypervascular HCCs and for the selection of appropriate treatment strategies,” the study’s authors wrote.

Reference

Fuji T, Nakamura Y, Fukumoto W, et al. Clinical indication for computed tomography during hepatic arteriography (CTHA) in addition to dynamic CT studies to identify hypervascularity of hepatocellular carcinoma. Cardiovasc Intervent Radiol. 2017 Nov 3. doi: 10.1007/s00270-017-1832-9. [Epub ahead of print]