Use of Contrast Media During CT-guided Thermal Ablation of Colorectal Liver Metastasis for Procedure Planning is Associated with Improved Immediate Outcomes

PURPOSE

The aim of this study was to analyze the impact of using intra-procedural pre-ablation contrast-enhanced CT prior to percutaneous thermal ablation (pre-ablation CECT) of colorectal liver metastases (CLM) on local outcomes.

MATERIALS AND METHODS

This retrospective analysis of a prospectively collected liver ablation registry included 144 consecutive patients (median age 57 years IQR [49, 65], 60% men) who underwent 173 CT-guided ablation sessions for 250 CLM between October 2015 and March 2020. In addition to oncologic outcomes, technical success was retrospectively evaluated using a biomechanical deformable image registration software for 3D-minimal ablative margin (3D-MAM) quantification. Bayesian regression was used to estimate effects of pre-ablation CECT on residual unablated tumor, 3D-MAM, and local tumor progression-free survival (LTPFS).

RESULTS

Pre-ablation CECT was acquired in 71/173 (41%) sessions. Residual unablated tumor was present in one (0.9%) versus nine tumors (6.6%) ablated with versus without using pre-ablation CECT, respectively (p = 0.024). Pre-ablation CECT use decreased the odds of residual disease on first follow-up by 78% (CI95% [5, 86]) and incomplete ablation (3D-MAM ≤ 0 mm) by 58% (CI95% [13, 122]). The odds ratio for residual unablated tumor for larger CLM was lower when pre-ablation CECT was used (odds ratio 1.0 with pre-ablation CECT vs. 2.52 without). Pre-ablation CECT use was not associated with improvements on LTPFS.

CONCLUSIONS

Pre-ablation CECT is associated with improved immediate outcomes by significantly reducing the incidence of residual unablated tumor and by mitigating the risk of incomplete ablation for larger CLM. We recommend performing baseline intra-procedural pre-ablation CECT as a standard imaging protocol.

LEVEL OF EVIDENCE

Level 3 (retrospective cohort study).

The tumor ghost on MRI after microwave ablation for hepatocellular carcinoma: A new modality to assess the ablative margin

PURPOSE

The ablated tumor ghost can be visually distinguished on MR images after ablation. This retrospective study aimed to assess the performance of tumor ghost on post-ablation contrast-enhanced MRI with excellular contrast agent gadolinium-DTPA in evaluating the ablative margin of hepatocellular carcinoma (HCC) after microwave ablation (MWA).

METHOD

315 HCC lesions less than 5 cm in 287 patients completely treated by MWA were enrolled in the study. The tumor ghost was characterized as a lower signal intensity area than the surrounding tissues of the ablation zone on T1WI imaging. The ablation margin (AM) status was classified into AM0 (＞5mm) and AM1 (＜5mm) according to the minimum distance between the tumor ghost and ablated zone. Inter-observer agreement between two radiologists on the AM assessment was analyzed using the Cohen κ coefficient. Multivariate analysis using Cox proportional hazard model was performed to investigate independent risk factors for LTP.

RESULTS

175 and 140 tumors were evaluated as AM0 and AM1 through tumor ghost. The inter-observer agreement level between two radiologists for assessment of AM was good (κ coefficient = 0.752, 95 % confidence interval: 0.679-0.825, p < 0.001). The mediate follow-up period was 32.2 months (range 3.0-60.8 months). The incidence of LTP in the AM0 lesions and AM1 lesions was 6.3 % (11/175) and 20.0 % (28/140), respectively. AM status was identified as an independent prognostic factor for LTP (HR 3.057, 95 % CI, 1.445-6.470, p = 0.003).

CONCLUSIONS

The assessment of the AM by tumor ghost on post-ablation MRI is an accurate and efficiently method for evaluating the completeness of microwave ablation for hepatocellular carcinoma.

Feasibility and Efficacy of Fusion Imaging Systems for Immediate Post Ablation Assessment of Liver Neoplasms: Protocol for a Rapid Systematic Review

Introduction:

Percutaneous thermal ablation is widely adopted as a curative treatment approach for unresectable liver neoplasms. Accurate immediate assessment of therapeutic response post-ablation is critical to achieve favourable outcomes. The conventional technique of side-by-side comparison of pre- and post-ablation scans is challenging and hence there is a need for improved methods, which will accurately evaluate the immediate post-therapeutic response.

Objectives and Significance:

This review summarizes the findings of studies investigating the feasibility and efficacy of the fusion imaging systems in the immediate post-operative assessment of the therapeutic response to thermal ablation in liver neoplasms. The findings could potentially empower the clinicians with updated knowledge of the state-of-the-art in the assessment of treatment response for unresectable liver neoplasms.

Methods and Analysis:

A rapid review will be performed on publicly available major electronic databases to identify articles reporting the feasibility and efficacy of the fusion imaging systems in the immediate assessment of the therapeutic response to thermal ablation in liver neoplasms. The risk of bias and quality of articles will be assessed using the Cochrane risk of bias tool 2.0 and Newcastle Ottawa tool.

Ethics and Dissemination:

Being a review, we do not anticipate the need for any approval from the Institutional Review Board. The outcomes of this study will be published in a peer-reviewed journal.

Highlights

Evaluation of the therapeutic response in liver neoplasms immediately post-ablation is critical to achieve favourable patient outcomes. We will examine the feasibility and technical efficacy of different fusion imaging systems in assessing the immediate treatment response post-ablation. The findings are expected to guide the clinicians with updated knowledge on the state-of-the-art when assessing the immediate treatment response for unresectable liver neoplasms.

Assessment of safety margin after microwave ablation of stage I NSCLC with three-dimensional reconstruction technique using CT imaging

Objective

To assess the ablative margin of microwave ablation (MWA) for stage I non-small cell lung cancer (NSCLC) using a three-dimensional (3D) reconstruction technique.

Materials and methods

We retrospectively analyzed 36 patients with stage I NSCLC lesions undergoing MWA and analyzed the relationship between minimal ablative margin and the local tumor progression (LTP) interval, the distant metastasis interval and disease-free survival (DFS). The minimal ablative margin was measured using the fusion of 3D computed tomography reconstruction technique.

Results

Univariate and multivariate analyses indicated that tumor size (hazard ratio [HR] = 1.91, P < 0.01; HR = 2.41, P = 0.01) and minimal ablative margin (HR = 0.13, P < 0.01; HR = 0.11, P < 0.01) were independent prognostic factors for the LTP interval. Tumor size (HR = 1.96, P < 0.01; HR = 2.35, P < 0.01) and minimal ablative margin (HR = 0.17, P < 0.01; HR = 0.13, P < 0.01) were independent prognostic factors for DFS by univariate and multivariate analyses. In the group with a minimal ablative margin < 5 mm, the 1-year and 2-year local progression-free rates were 35.7% and 15.9%, respectively. The 1-year and 2-year distant metastasis-free rates were 75.6% and 75.6%, respectively; the 1-year and 2-year disease-free survival rates were 16.7% and 11.1%, respectively. In the group with a minimal ablative margin ≥ 5 mm, the 1-year and 2-year local progression-free rates were 88.9% and 69.4%, respectively. The 1-year and 2-year distant metastasis-free rates were 94.4% and 86.6%, respectively; the 1-year and 2-year disease-free survival rates were 88.9% and 63.7%, respectively. The feasibility of 3D quantitative analysis of the ablative margins after MWA for NSCLC has been validated.

Conclusions

The minimal ablative margin is an independent factor of NSCLC relapse after MWA, and the fusion of 3D reconstruction technique can feasibly assess the minimal ablative margin.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12880-021-00626-z.

Combination therapy by transarterial injection of miriplatin-iodized oil suspension with radiofrequency ablation (RFA) versus microwave ablation (MWA) for small hepatocellular carcinoma: a comparison of therapeutic efficacy

PURPOSE

To compare the technical efficacy and complications of the transarterial injection of a miriplatin-iodized oil suspension combined with radiofrequency ablation (RFA) or microwave ablation (MWA) in the treatment of small hepatocellular carcinomas (HCCs).

MATERIALS AND METHODS

This retrospective study included 123 HCCs in 101 patients treated with the transarterial injection of a miriplatin-iodized oil suspension and RFA (MPT-RFA) (maximum diameter: 1.5 [Formula: see text] 0.5 cm, range: 0.6-3.0 cm) and 68 HCCs in 49 patients treated with the transarterial injection of a miriplatin-iodized oil suspension and MWA (MPT-MWA) (maximum diameter: 1.6 [Formula: see text] 0.7 cm, range: 0.5-3.0 cm). Technical success was defined as the achievement of an ablative margin of at least 5 mm for each tumor. Technical success, complications, and local tumor progression were compared between the two groups.

RESULTS

The initial technical success rate was significantly higher with MPT-MWA (94.1%) than with MPT-RFA (76.4%; P = 0.003). The number of treatment sessions per nodule was significantly lower with MPT-MWA (1.1) than with MPT-RFA (1.3) (P = 0.004). The major complication rates were similar with MPT-RFA (5.8%) and MPT-MWA (2.7%) (P = 0.391). The one-year local tumor progression rate was similar between MPT-RFA (0%) and MPT-MWA (0%) (P = 0.73).

CONCLUSION

MPT-MWA may have improved therapeutic efficiency in the treatment of small HCCs.

Preablation three-dimensional ultrasonography can predict therapeutic effect and local tumor progression after radiofrequency ablation for hepatocellular carcinoma

PURPOSE

To assess the agreement between ablative margin (AM) predicted by preablation three-dimensional ultrasonography (3D-US) and AM measured on postablation computed tomography (CT)/magnetic resonance (MR) images.

METHODS

Sixty patients with 73 hepatocellular carcinoma nodules were enrolled. 3D-US data were collected immediately after puncture by the electrode before ablation. The maximum distance from the electrode to the edge of the tumor in the plane perpendicular to the electrode (C-plane) was defined as "a" and the diameter of the ablation zone as "b". We classified predicted AM into "0.5b - a" ≥0 mm as AM(+) or <0 mm as AM(-), and "0.5b - a" ≥3 mm or <3 mm.

RESULTS

Forty-eight nodules (66 %) were visualized in the C-plane. There was an agreement between the predicted and measured AMs for 39 (81 %) of the 48 nodules. Local tumor progression was observed in 3 (7%) of 43 nodules with predicted AM(+) and in 2 (40 %) of 5 nodules with predicted AM(-) but was not observed in any of 21 nodules with predicted AM ≥ 3 mm. The local tumor progression rate was significantly lower for nodules with predicted AM(+) compared with predicted AM(-)(p = 0.03), and for nodules with predicted AM ≥ 3 mm compared with predicted AM < 3 mm (p = 0.04). Local progression was detected in 2 (4.7 %) of 42 nodules with a sufficient AM (≥0 mm) on postablation CT/MR images and in 5 (83.3 %) of 6 nodules with an insufficient AM (<0 mm); the difference in progression rate was significant (p = 0.0008).

CONCLUSION

3D-US allows prediction of the AM before radiofrequency ablation.

Feasibility of CT-CT fusion imaging for evaluation of the cryoablation margins in visible hepatocellular carcinoma on unenhanced CT images: Initial experience

Objective

To demonstrate the feasibility of CT-CT fusion imaging for assessment of the cryoablation margins in visible hepatocellular carcinoma (HCC) on unenhanced CT images.

Methods

This retrospective study analyzed 14 patients with 14 HCC lesions treated with CT-guided cryoablation. Nine lesions in nine patients who developed local tumor progression (LTP) during the follow-up period of at least 8 months were reviewed. The unenhanced CT data were used to retrospectively create fusion images of the intraoperative CT images on a workstation. The minimal ablative margin (MAM) was assessed on the fusion images. The concordance between the site of LTP and the MAM area was also assessed.

Results

Eight of the nine lesions with LTP were in the subcapsular region of the liver. Seven of the nine cases were treated by cryoablation combined with transcatheter arterial chemoembolization. The median time required to fuse the images for the nine lesions was 5:17 min (range, 5:04–7:37 min). The site of LTP relative to the HCC lesion was craniocaudal in nine, dorsoventral in six, and lateral in seven lesions. In all lesions, the site of LTP was congruent with the MAM area.

Conclusions

CT-CT fusion imaging enables a real-time intraoperative treatment evaluation for HCC lesions visible on unenhanced CT images. Fused imaging evaluation has proved to be an accurate and useful tool for assessment of the cryoablation margins.

Imaging evaluation of ablative margin and index tumor immediately after radiofrequency ablation for hepatocellular carcinoma: comparison between multidetector-row CT and MR imaging

PURPOSE

To prospectively compare multidetector-row CT (MDCT) and MR imaging (MRI) in the assessment of the ablative margin (AM) and index tumor immediately after radiofrequency (RF) ablation for hepatocellular carcinoma (HCC) and assess whether non-contrast MRI with limited sequences (T1- and T2-weighted imaging only) was superior to a conventional MDCT protocol.

METHODS

A total of 33 consecutive patients with 42 HCCs were included in this study. Both MDCT and MR images were independently reviewed by two radiologists regarding the ability to visually discriminate between the AM and index tumor, and the AM status within ablation zones. The AM status was classified as AM-plus (AM completely surrounding the tumor), AM-zero (AM was partly discontinuous, without protrusion of the tumor), and AM-minus (AM was partly discontinuous, with protrusion of the tumor). During the follow-up period, the cumulative local tumor progression rates were analyzed using the Kaplan-Meier method and Cox proportional hazards model. To determine the added value of contrast-enhanced MR images, both reviewers separately evaluated the two sets (unenhanced and enhanced) of MR images.

RESULTS

Visual discrimination between the AM and index tumor was possible in four (9.5%) and 34 (81%) of the 42 ablation zones using MDCT and MRI, respectively (p < 0.001). Thirty-eight and four cases were classified as AM-plus and AM-zero on MDCT images, respectively, whereas the ablation zones were categorized as AM-plus (n = 32), AM-zero (n = 9), and AM-minus (n = 1) when examining the MR images. The cumulative incidence of local tumor progression was significantly lower in cases with AM-plus on MRI (p = 0.007). Contrast-enhanced MRI had no added value for the assessment of the AM and index tumor.

CONCLUSION

MRI was superior to MDCT for the differential assessment of the AM and index tumor immediately after RF ablation for HCC. Non-contrast MRI was also superior to the conventional MDCT protocol.

Rate of local tumor progression following radiofrequency ablation of pathologically early hepatocellular carcinoma

AIM

To evaluate whether pathologically early hepatocellular carcinoma (HCC) exhibited local tumor progression after radiofrequency ablation (RFA) less often than typical HCC.

METHODS

Fifty pathologically early HCCs [tumor diameter (mm): mean, 15.8; range, 10-23; follow-up days after RFA: median, 1213; range, 216-2137] and 187 typical HCCs [tumor diameter (mm): mean, 15.6; range, 6-30; follow-up days after RFA: median, 1116; range, 190-2328] were enrolled in this retrospective study. The presence of stromal invasion (namely, tumor cell invasion into the intratumoral portal tracts) was considered to be the most important pathologic finding for the diagnosis of early HCCs. Typical HCC was defined as the presence of a hyper-vascular lesion accompanied by delayed washout using contrast-enhanced computed tomography or contrast-enhanced magnetic resonance imaging. Follow-up examinations were performed at 3-mo intervals to monitor for signs of local tumor progression. The local tumor progression rates of pathologically early HCCs and typical HCCs were then determined using the Kaplan-Meier method.

RESULTS

During the follow-up period for the 50 pathologically early HCCs, 49 (98%) of the nodules did not exhibit local tumor progression. However, 1 nodule (2%) was associated with a local tumor progression found 636 d after RFA. For the 187 typical HCCs, 46 (24.6%) of the nodules exhibited local recurrence after RFA. The follow-up period until the local tumor progression of typical HCC was a median of 605 d, ranging from 181 to 1741 d. Among the cases with typical HCCs, local tumor progression had occurred in 7.0% (7/187), 16.0% (30/187), 21.9% (41/187) and 24.6% (46/187) of the cases at 1, 2, 3 and 4 years, respectively. Pathologically early HCC was statistically associated with a lower rate of local tumor progression, compared with typical HCC, when evaluated using a log-rank test (P = 0.002).

CONCLUSION

The rate of local tumor progression for pathologically early HCCs after RFA was significantly lower than that for typical HCCs.

Improvement of ablative margins by the intraoperative use of CEUS-CT/MR image fusion in hepatocellular carcinoma

BACKGROUND

To assess whether intraoperative use of contrast-enhanced ultrasound (CEUS)-CT/MR image fusion can accurately evaluate ablative margin (AM) and guide supplementary ablation to improve AM after hepatocellular carcinoma (HCC) ablation.

METHODS

Ninety-eight patients with 126 HCCs designated to undergo thermal ablation treatment were enrolled in this prospective study. CEUS-CT/MR image fusion was performed intraoperatively to evaluate whether 5-mm AM was covered by the ablative area. If possible, supplementary ablation was applied at the site of inadequate AM. The CEUS image quality, the time used for CEUS-CT/MR image fusion and the success rate of image fusion were recorded. Local tumor progression (LTP) was observed during follow-up. Clinical factors including AM were examined to identify risk factors for LTP.

RESULTS

The success rate of image fusion was 96.2% (126/131), and the duration required for image fusion was 4.9 ± 2.0 (3-13) min. The CEUS image quality was good in 36.1% (53/147) and medium in 63.9% (94/147) of the cases. By supplementary ablation, 21.8% (12/55) of lesions with inadequate AMs became adequate AMs. During follow-up, there were 5 LTPs in lesions with inadequate AMs and 1 LTP in lesions with adequate AMs. Multivariate analysis showed that AM was the only independent risk factor for LTP (hazard ratio, 9.167; 95% confidence interval, 1.070-78.571; p = 0.043).

CONCLUSION

CEUS-CT/MR image fusion is feasible for intraoperative use and can serve as an accurate method to evaluate AMs and guide supplementary ablation to lower inadequate AMs.

Clinical usefulness of the ablative margin assessed by magnetic resonance imaging with Gd-EOB-DTPA for radiofrequency ablation of hepatocellular carcinoma

BACKGROUND & AIMS

The aim of this study was to investigate the feasibility of ablative margin (AM) grading by magnetic resonance imaging (MRI) with Gd-EOB-DTPA administered prior to radiofrequency ablation (RFA), and to identify factors for achieving a sufficient AM and predictors for local tumor progression.

METHODS

A total of 124 hepatocellular carcinomas (HCCs) were treated by RFA after Gd-EOB-DTPA administration. MRI and enhanced CT were performed within seven hours and one month after RFA. The AM assessment was categorized using three grades: AM (+), low-intensity area with continuous high-intensity rim; AM zero, low-intensity area with discontinuous high-intensity rim; and AM (-), low-intensity area extends beyond the high-intensity rim. Patients were followed and local tumor progression was observed.

RESULTS

AM (+), AM zero, AM (-), and indeterminate were found in 34, 33, 26, and 31 nodules, respectively. The overall agreement rate between MRI and enhanced CT for the diagnosis of AM was 56.8%. The κ coefficient was 0.326 (p<0.001), indicating moderate agreement. Multivariate logistic regression analysis showed that a significant factor for the achievement of AM (+) on MRI was no contiguous vessels. The cumulative local tumor progression rates (0% at 1, 2, and 3 years) in 33 AM (+) nodules were significantly lower than those (3.6%, 11.5%, and 18.3% at 1, 2, and 3 years respectively) in 32 AM zero nodules. A multivariate Cox proportional hazards model identified tumor size as an independent predictor for local tumor progression.

CONCLUSION

Gd-EOB-DTPA-MRI enabled an early assessment of RFA effectiveness in the majority ofHCC nodules. Local tumor progression was not detected in AM (+) nodules during the follow-up.

Ultrasound-Guided Percutaneous Radiofrequency Ablation of Liver Tumors: How We Do It Safely and Completely

Ultrasound-guided percutaneous radiofrequency (RF) ablation has become one of the most promising local cancer therapies for both resectable and nonresectable hepatic tumors. Although RF ablation is a safe and effective technique for the treatment of liver tumors, the outcome of treatment can be closely related to the location and shape of the tumors. There may be difficulties with RF ablation of tumors that are adjacent to large vessels or extrahepatic heat-vulnerable organs and tumors in the caudate lobe, possibly resulting in major complications or treatment failure. Thus, a number of strategies have been developed to overcome these challenges, which include artificial ascites, needle track ablation, fusion imaging guidance, parallel targeting, bypass targeting, etc. Operators need to use the right strategy in the right situation to avoid the possibility of complications and incomplete thermal tissue destruction; with the right strategy, RF ablation can be performed successfully, even for hepatic tumors in high-risk locations. This article offers technical strategies that can be used to effectively perform RF ablation as well as to minimize possible complications related to the procedure with representative cases and schematic illustrations.

Assessment of radiofrequency ablation margin by MRI-MRI image fusion in hepatocellular carcinoma

AIM

To investigate the feasibility and clinical value of magnetic resonance imaging (MRI)-MRI image fusion in assessing the ablative margin (AM) for hepatocellular carcinoma (HCC).

METHODS

A newly developed ultrasound workstation for MRI-MRI image fusion was used to evaluate the AM of 62 tumors in 52 HCC patients after radiofrequency ablation (RFA). The lesions were divided into two groups: group A, in which the tumor was completely ablated and 5 mm AM was achieved (n = 32); and group B, in which the tumor was completely ablated but 5 mm AM was not achieved (n = 29). To detect local tumor progression (LTP), all patients were followed every two months by contrast-enhanced ultrasound, contrast-enhanced MRI or computed tomography (CT) in the first year after RFA. Then, the follow-up interval was prolonged to every three months after the first year.

RESULTS

Of the 62 tumors, MRI-MRI image fusion was successful in 61 (98.4%); the remaining case had significant deformation of the liver and massive ascites after RFA. The time required for creating image fusion and AM evaluation was 15.5 ± 5.5 min (range: 8-22 min) and 9.6 ± 3.2 min (range: 6-14 min), respectively. The follow-up period ranged from 1-23 mo (14.2 ± 5.4 mo). In group A, no LTP was detected in 32 lesions, whereas in group B, LTP was detected in 4 of 29 tumors, which occurred at 2, 7, 9, and 15 mo after RFA. The frequency of LTP in group B (13.8%; 4/29) was significantly higher than that in group A (0/32, P = 0.046). All of the LTPs occurred in the area in which the 5 mm AM was not achieved.

CONCLUSION

The MRI-MRI image fusion using an ultrasound workstation is feasible and useful for evaluating the AM after RFA for HCC.

Radiofrequency ablation of hepatocellular carcinoma sized > 3 and ≤ 5 cm: Is ablative margin of more than 1 cm justified?

AIM: To investigate whether an ablative margin (AM) > 1.0 cm might reduce chance of recurrence for patients with hepatocellular carcinoma (HCC) tumors 3.1 to 5.0 cm in size, compared with an AM of 0.5-1.0 cm.

METHODS: From October 2005 to December 2012, 936 consecutive patients with HCC who received radiofrequency ablation were screened. Of these, 281 patients, each with a single primary HCC tumor of 3.1 to 5.0 cm in size on its greatest diameter, were included in the study. Based on the AM width, we categorized patients into the 0.5-1.0 cm group and the > 1.0 cm group. Local tumor progression (LTP)-free survival, intrahepatic distant recurrence (IDR)-free survival and overall survival (OS) rates were obtained using the Kaplan-Meier method.

RESULTS: The 1-, 2-, 3-, 4-, and 5-year LTP-free survival rates and IDR-free survival rates were significantly higher in the > 1.0 cm group compared with the 0.5-1.0 cm group (97.5%, 86.3%, 73.6%, 49.5% and 26.4% vs 91.3%, 78.4%, 49.5%, 27.8%, and 12.8%; 95.1%, 90.3%, 77.0%, 61.0% and 48.3% vs 95.2%, 85.9%, 62.6%, 47.2% and 28.5%; P < 0.05). The 1-, 2-, 3-, 4-, and 5-year OS rates were 98.6%, 91.5%, 69.2%, 56.0% and 42.2%, respectively, in the 0.5-1.0 cm group and 100%, 98.9%, 90.1%, 68.7% and 57.4%, respectively, in the > 1.0 cm group (P = 0.010). There were no significant differences in complication rates between the two groups. Both univariate and multivariate analyses identified AM as an independent prognostic factor linked to LTP, IDR, and OS.

CONCLUSION: For HCC tumors > 3.0 cm and ≤ 5.0 cm, AM > 1.0 cm could reduce chances of recurrence compared with AM of 0.5-1.0 cm, emphasizing the need for a more defensive strategy using AMs > 1.0 cm for ablating HCC tumors of 3.1 to 5.0 cm.