Early prediction of 1-year tumor response of hepatocellular carcinoma with lipiodol deposition pattern through post-embolization cone-beam computed tomography during conventional transarterial chemoembolization

Creation of a Prediction Model of Local Tumor Recurrence After a Successful Conventional Transcatheter Arterial Chemoembolization Using Cone-Beam Computed Tomography Based-Radiomics

PURPOSE

To create and evaluate prediction models of local tumor recurrence after successful conventional transcatheter arterial chemoembolization (c-TACE) via radiomics analysis of lipiodol deposition using cone-beam computed tomography (CBCT) images obtained at the completion of TACE.

MATERIALS AND METHODS

A total of 103 hepatocellular carcinoma nodules in 71 patients, who achieved a complete response (CR) based on the modified Response Evaluation Criteria in Solid Tumors 1 month after TACE, were categorized into two groups: prolonged CR and recurrence groups. Three types of areas were segmented on CBCT: whole segment (WS), tumor segment (TS), and peritumor segment (PS). From each segment, 105 radiomic features were extracted. The nodules were randomly divided into training and test datasets at a ratio of 7:3. Following feature reduction for each segment, three models (clinical, radiomics, and clinical-radiomics models) were developed to predict recurrence based on logistic regression.

RESULTS

The clinical-radiomics model of WS showed the best performance, with the area under the curve values of 0.853 (95% confidence interval: 0.765-0.941) in training and 0.752 (0.580-0.924) in test dataset. In the analysis of radiomic feature importance of all models, among all radiomic features, glcm_MaximumProbability, shape_MeshVolume and shape_MajorAxisLength had negative coefficients. In contrast, shape_SurfaceVolumeRatio, shape_Elongation, glszm_SizeZoneNonUniformityNormalized, and gldm_GrayLevelNonUniformity had positive coefficients.

CONCLUSION

In this study, a machine-learning model based on cone-beam CT images obtained at the completion of c-TACE was able to predict local tumor recurrence after successful c-TACE. Nonuniform lipiodol deposition and irregular shapes may increase the likelihood of recurrence.

Assessment of abdominal organ dose and image quality in varying arc trajectory interventional C-arm cone beam CT

PURPOSE

The aim of this study was to investigate the effect of varying arc exposure trajectory on radiation dose to radiosensitive organs and to assess image quality in abdominal C-arm cone beam computed tomography (CBCT) interventional procedures using a latest generation system.

METHODS

An anthropomorphic phantom that simulates the average adult individual was used. Individual-specific Monte Carlo (MC) simulation dosimetry was performed to estimate organ doses (OD) in abdominal C-arm CBCT. Seven examination protocols prescribed by the system for vascular and soft tissue CBCT, were simulated. These protocols are differentiated in the range of the arc exposure trajectory and the level of radiation dose delivered to the patient. OD was estimated for liver, adrenals, kidneys, pancreas, stomach, gall bladder, spleen, bone and skin. Image noise, signal to noise ratio (SNR), contrast to noise ratio (CNR) and in-plane spatial resolution were assessed using CT-specific image quality assessment phantoms.

RESULTS

OD was found to depend on the range of arc trajectory and was higher for posterior located organs. In vascular protocols OD ranged from 4.75 mGy for skin to 0.60 mGy for bone. Image noise was higher in vascular protocols than in soft tissue ones. SNR and CNR were significantly modified among different soft tissue protocols (P < 0.05). In-plane spatial resolution was found 0.80 lp/mm in vascular as opposed to 0.41 lp/mm in soft tissue protocols.

CONCLUSIONS

The current results may be used to estimate OD for different examination protocols and enable operators choose the appropriate acquisition protocol on the preprogrammed interventional task.

Redefining Tumor Burden in Patients with Intermediate-Stage Hepatocellular Carcinoma: The Seven-Eleven Criteria

BACKGROUND AND AIMS

For patients with intermediate-stage hepatocellular carcinoma (HCC), the definition of high tumor burden remains controversial. This study aimed to compare the prognostic value of different criteria of tumor burden in patients with intermediate-stage HCC undergoing transarterial chemoembolization (TACE).

METHODS

From 2007 to 2019, 632 treatment-naive patients with intermediate-stage HCC undergoing TACE were retrospectively enrolled. We compared different criteria of tumor burden in discriminating radiologic response and survival, including up-to-7, up-to-11, 5-7, 7 lesions criteria, and newly proposed 7-11 criteria.

RESULTS

The proportions of patients classified as high tumor burden were varied by different criteria. Among the 5 criteria, 7-11 criteria have the best performance to discriminate complete response (CR) and overall survival (OS) after TACE. In patients with low, intermediate, and high tumor burden classified by 7-11 criteria, the CR rate was 21, 12, and 2.5%, respectively (p < 0.001), and the median OS was 33.1, 22.3, and 11.9 months, respectively (p < 0.001). By multivariate analysis, 7-11 criteria were significantly associated with CR (intermediate vs. high burden, odds ratio = 4.617, p = 0.002; low vs. high burden, odds ratio = 8.675, p < 0.001) and OS (intermediate vs. high burden, hazard ratio = 0.650, p < 0.001; low vs. high burden, hazard ratio = 0.520, p < 0.001). Seven to 11 criteria also had the lowest corrected Akaike information criteria, highest homogeneity value, and highest area under the receiver operating characteristic curve in predicting 1-, 2-, and 3-year mortality among all criteria.

CONCLUSION

Conventional definitions of tumor burden were not optimal for patients with intermediate HCC. The new 7-11 criteria had the best discriminative power in predicting radiologic response and survival in patients with intermediate-stage HCC undergoing TACE.