Angio-Computed Tomograph-Guided Immediate Lipiodol Computed Tomograph for Diagnosis of Small Hepatocellular Carcinoma Lesions during Transarterial Chemoembolization

Abstract

Background: The diagnosis and treatment of small hepatocellular carcinoma (HCC) play a vital role in the prognosis of patients with HCC. The purpose of our study was to evaluate angio-computed tomography (angio-CT)-guided immediate lipiodol CT (a CT scan performed immediately after transarterial chemoembolization [TACE]) in the diagnosis of potential HCCs ≤1 cm in diameter.

Methods: This study retrospectively analyzed 31 patients diagnosed with HCCs after routine imaging (contrast-enhanced CT or magnetic resonance imaging) or pathologic examinations with undefined or undetermined tumor lesions (diameter ≤1 cm) from February 2016 to September 2016. After TACE guided by digital subtraction angiography of the angio-CT system, potential HCC lesions with a diameter ≤1 cm were diagnosed by immediate lipiodol CT. The number of well-demarcated lesions was recorded to calculate the true positive rate. The correlation between the number of small HCCs detected by immediate lipiodol CT and the size of HCC lesions (diameter >1 cm) diagnosed preoperatively was analyzed 1 month after TACE. A paired t-test was used to analyze differences in liver function. Pearson analysis was used to analyze correlation. Chi-square test was used to compare the rates.

Results: Fifty-eight lesions were detected on preoperative routine imaging examinations in 31 patients including 15 lesions with a diameter ≤1 cm. Ninety-one lesions were detected on immediate lipiodol CT, of which 48 had a diameter ≤1 cm. After 1 month, CT showed that 45 lesions had lipiodol deposition and three lesions had lipiodol clearance. Correlation analysis showed that the number of small HCCs detected by lipiodol CT was positively correlated with the size of HCC lesions diagnosed by conventional imaging examination (R² = 0.54, P < 0.05).

Conclusion: Immediate lipiodol CT may be a useful tool in the diagnosis of potential HCC lesions with a diameter of ≤1 cm.

Keywords: Chemoembolization; Diagnostic Imaging; Hepatocellular Carcinoma; Lipiodol Computed Tomograph; Liver Neoplasms; Therapeutic.

Figure 1

The small HCC lesion was detected by immediate lipiodol CT in a 72-year-old female patient with HCC who received TACE in angio-CT. (a and b) Preoperative enhanced CT showed a homogeneous enhancement in the right lobe of the liver and caudate lobe enlargement (white arrows); (c) immediate lipiodol CT showed lipiodol deposition in the right lobe of the liver, which was consistent with the results of preoperative enhanced CT (black thick arrow: TACE treatment area), and the caudate lobe of the liver had obvious lipiodol deposition (black thin arrow); (d) immediate lipiodol CT imaging identified another small HCC lesion in the right lobe of the liver (black arrow). HCC: Hepatocellular carcinoma; CT: Computed tomograph; TACE: Transarterial chemoembolization.

Figure 2

The small HCC lesion was detected by immediate lipiodol CT in a 42-year-old male patient with HCC who received TACE in angio-CT. (a) Preoperative MRI enhanced scan showed an obvious enhancement in the arterial phase of the left and right lobe of the liver (white arrow); (b) intraoperative DSA showed a mass shadow (black thick arrow) at the location consistent with the preoperative MRI examination; (c) immediate lipiodol CT showed an area of lipiodol deposition consistent with preoperative MRI examination (black thin arrow); (d) immediate lipiodol CT imaging identified another small HCC lesion (black thin arrow) but not by preoperative MRI and intraoperative DSA. HCC: Hepatocellular carcinoma; CT: Computed tomograph; TACE: Transarterial chemoembolization; MRI: Magnetic resonance imaging; DSA: Digital subtraction angiography.

Figure 3

The false-positive lesions identified by immediate lipiodol CT after TACE in a 53-year-old male patient with HCC. (a and b) Preoperative MRI and intraoperative DSA revealed a tumor in the liver (black arrows); (c and d) immediate lipiodol CT showed an area of lipiodol deposition (black arrow) consistent with pre-operative MRI examination and intra-operative DSA. In addition, immediate lipiodol CT showed two small lesions (red arrows) which were not detected by pre-operative MRI examination and intraoperative DSA; (e) after 1 month, CT scan revealed that iodized oil was not cleared from one lesion (black arrow) diagnosed by pre-operative MRI and intra-operative DSA and another one lesion detected by immediate lipiodol CT (true positive, red arrow); (f) CT scan revealed that iodized oil was cleared in another one lesion detected by immediate lipiodol CT after 1 month (false positive, red triangle). CT: Computed tomograph; TACE: Transarterial chemoembolization; HCC: Hepatocellular carcinoma; MRI: Magnetic resonance imaging; DSA: Digital subtraction angiography.

Figure 4

The true-positive lesions identified by immediate lipiodol CT after TACE in a 57-year-old male patient with HCC. (a-c) Preoperative MRI revealed two HCCs in the liver (black arrows); (d-f) Immediate lipiodol CT showed the two areas of lipiodol deposition (black arrows) consistent with the preoperative MRI. Immediate lipiodol CT identified four small lesions (red arrows) which were not detected by preoperative MRI; (g-i) after 1 month, CT scan revealed that diffuse lipiodol in the liver has cleared, and iodized oil was not cleared from the two lesions (black arrows) diagnosed by preoperative MRI and the four lesions detected by immediate lipiodol CT (true positive, red triangles). CT: Computed tomograph; TACE: Transarterial chemoembolization; HCC: Hepatocellular carcinoma; MRI: Magnetic resonance imaging.

Figure 5

Pearson's correlation analysis for the relationship between the number of small HCC lesions (diameter ≤1 cm) detected by lipiodol CT and the size of HCCs diagnosed by conventional imaging examinations in 31 patients (R² = 0.54, P < 0.05). HCC: Hepatocellular carcinoma; CT: Computed tomograph.