Puncture accuracy of an optical tracked robotic aiming device-a phantom study.

OBJECTIVES: To evaluate the targeting accuracy of stereotactic punctures based on a hybrid robotic device in combination with optical tracking-a phantom study. METHODS: CT data sets of a gelatin-filled plexiglass phantom with 1-, 3-, and 5-mm slice thickness were acquired. An optical navigation device served for planning of a total of 150 needle trajectories. All punctures were carried out semi-automatically with help of the trackable iSYS-1 robotic device. Conically shaped targets inside the phantom were punctured using Kirschner wires. Up to 8 K-wires were positioned sequentially based on the same planning CT and placement accuracy was assessed by taking control CTs and measuring the Euclidean (ED) and normal distances (NDs) between the wire and the entry and target point. RESULTS: Using the StealthStation S7, the accomplished mean ND at the target for the 1-mm, 3-mm, and 5-mm slice thickness was 0.89 mm (SD ± 0.42), 0.93 mm (SD ± 0.45), and 0.73 mm (SD ± 0.50), respectively. The corresponding mean ED was 1.61 mm (SD ± 0.36), 2.04 mm (SD ± 0.59), and 1.76 mm (SD ± 0.45). The mean duration of the total procedure was 27.9 min, including image acquisition, trajectory planning, registration, placement of 8 wires, and the control-CT. CONCLUSIONS: The optically tracked iSYS-1 robot allows for precise punctures in a phantom. The StealthStation S7 provided acceptable results and may be helpful for interventions in difficult anatomical regions and for those requiring complex multi-angle trajectories. In combination with our optical navigation tool, the trackable robot unit allows to cover a large treatment field and the compact design facilitates placement of needle-like instruments. KEY POINTS: • The use of a robotic targeting device in combination with optical tracking (hybrid system) allows for accurate placement of needle-like instruments without repeated control imaging. • The compact robotic positioning unit in combination with a camera for optical tracking facilitates sequential placement of multiple K-wires in a large treatment volume.

Stereotactic radiofrequency ablation as a valid first-line treatment option for hepatocellular adenomas.

OBJECTIVES: This study aimed to assess the safety and efficacy of stereotactic radiofrequency ablation (SRFA) in patients with hepatocellular adenomas (HCA). METHODS: Retrospective analyses of all patients referred for SRFA treatment at our institution between January 2010 and October 2020 revealed 14 patients (10 women; mean age 34.4 [range, 17-73 years]) with 38 HCAs treated through 18 ablation sessions. Ablations were considered successful if a safety margin >5 mm was achieved. Demographic, interventional, and outcome data were collected and analyzed. Primary and secondary technical efficacy rates were assessed based on follow-up images consisting of contrast-enhanced CT or MR scans. RESULTS: The mean tumor size was 22 mm (range, 7-75 mm). Overall, 37/38 (97.4%) tumors were successfully ablated at the initial SRFA (primary efficacy rate of 97.4%). The median follow-up duration was 49.6 months. No deaths or adenoma-related complications (hemorrhage or malignant transformation) were observed. Disease-free survival rates at 1, 3, and 5 years from the date of the first SRFA were 100%, 85.8%, and 85.8%, respectively. Two patients developed new distant tumors retreated with consecutive re-ablation. No major complications occurred during any of the 18 ablation sessions. CONCLUSIONS: Percutaneous thermal ablation is efficient in the treatment of HCAs and may thus be considered a valid first-line treatment option. In addition, SRFA allows for an effective, minimally invasive treatment of large and multiple hepatic tumors within one session.

Technical efficacy and local recurrence after stereotactic radiofrequency ablation of 2653 liver tumors: a 15-year single-center experience with evaluation of prognostic factors.

PURPOSE: To assess the technical outcome and local tumor control of multi-probe stereotactic radiofrequency ablation (SRFA) in a large series of patients. Furthermore, to determine factors accounting for adverse outcomes. MATERIAL AND METHODS: Between 2003 and 2018, 865 patients were treated by SRFA for 2653 primary and metastatic liver tumors with a median tumor size of 2.0 cm (0.5 - 19 cm). Primary technical efficacy (PTE) and local recurrence (LR) were evaluated, and possible predictors for adverse events analyzed using uni- and multi-variable binary logistic regression. RESULTS: Overall, 2553 of 2653 tumors were successfully ablated at initial SRFA resulting in a PTE rate of 96.2%. Predictors of lower PTE rates were age > 70 years, tumor size > 5 cm, number of probes, location close to liver capsule/organs and segment II. LR occurred in 220 of 2653 tumors (8.3%) with the following predictors: age, tumor type/size, conglomerates, segments I/IVa/IVb, number of probes and location close to major vessels/bile duct. Multivariable analysis revealed tumor size > 5 cm (odds ratio [OR] 3.153), age > 70 years (OR 1.559), and location in segment II (OR 1.772) as independent prognostic factors for PTE, whereas tumor location close to major vessels (OR 1.653) and in segment IVb (OR 2.656) were identified as independent prognostic factors of LR. CONCLUSIONS: Stereotactic RFA is an attractive option in the management of primary or metastatic liver tumors with good local tumor control, even in large tumors. The presented prognostic factors for adverse local oncological outcome might help to stratify unfavorable tumors for ablation.

Stereotactic radiofrequency ablation of tumors at the hepatic venous confluence.

BACKGROUND: Radiofrequency ablation (RFA) is subject to "heat-sink" effects, particularly for treatment of tumors adjacent to major vessels. METHODS: In this retrospective study, 104 patients with 137 tumors (40 HCC, 10 ICC and 54 metastatic liver tumors) close to (≤1 cm from) the hepatic venous confluence underwent stereotactic RFA (SRFA) between June 2003 and June 2018. Median tumor size was 3.7 cm (1.4-8.5) for HCC, 6.4 cm (0.5-11) for ICC and 3.8 cm (0.5-13) for metastases. Endpoints comprised safety, local tumor control, overall and disease-free survival. RESULTS: The overall major complication rate was 16.0% (20/125 ablations), where 8 (40%) were successfully treated by the interventional radiologist in the same anesthetic session and did not prolong hospital stay. 134/137 (97.8%) tumors were successfully ablated at initial SRFA. Local recurrence (LR) developed in 19/137 tumors (13.9%). The median and overall survival (OS) rates at 1-, 3-, and 5- years from the date of the first SRFA were 51.5 months, 73.5%, 67.0%, and 49.7% for HCC, 14.6 months, 60.0%, 32.0% and 32.0% for ICC and 38.1 months, 91.4%, 56.5% and 27.9% for metastatic disease, respectively. CONCLUSION: SRFA represents a viable alternative to hepatic resection for challenging tumors at the hepatic venous confluence.

Volumetric assessment of the periablational safety margin after thermal ablation of colorectal liver metastases.

OBJECTIVES: To retrospectively assess the periablational 3D safety margin in patients with colorectal liver metastases (CRLM) referred for stereotactic radiofrequency ablation (RFA) and to evaluate its influence on local treatment success. METHODS: Forty-five patients (31 males; mean age 64.5 [range 31-87 years]) with 76 CRLM were treated with stereotactic RFA and retrospectively analyzed. Image fusion of pre- and post-interventional contrast-enhanced CT scans using a non-rigid registration software enabled a retrospective assessment of the percentage of predetermined periablational 3D safety margin and CRLM successfully ablated. Periablational safety zones (1-10 mm) and percentage of periablational zone ablated were calculated, analyzed, and compared with subsequent tumor growth to determine an optimal safety margin predictive of local treatment success. RESULTS: Mean overall follow-up was 36.1 ± 18.5 months. Nine of 76 CRLMs (11.8%) developed local tumor progression (LTP) with mean time to LTP of 18.3 ± 11.9 months. Overall 1-, 2-, and 3-year cumulative LTP-free survival rates were 98.7%, 90.6%, and 88.6%, respectively. The periablational safety margin assessment proved to be the only independent predictor (p < 0.001) of LTP for all calculated safety margins. The smallest safety margin 100% ablated displaying no LTP was 3 mm, and at least 90% of a 6-mm circumscribed 3D safety margin was required to achieve complete ablation. CONCLUSIONS: Volumetric assessment of the periablational safety margin can be used as an intraprocedural tool to evaluate local treatment success in patients with CRLM referred to stereotactic RFA. Ablations achieving 100% 3D safety margin of 3 mm and at least 90% 3D safety margin of 6 mm can predict treatment success. KEY POINTS: • Volumetric assessment of the periablational safety margin can be used as an intraprocedural tool to evaluate local treatment success following thermal ablation of colorectal liver metastases. • Ablations with 100% 3D periablational safety margin of 3 mm and ablations with at least 90% 3D safety margin of 6 mm can be considered indications of treatment success. • Image fusion of pre- and post-interventional CT scans with the software used in this study is feasible and could represent a useful tool in daily clinical practice.

Frequency and risk factors for major complications after stereotactic radiofrequency ablation of liver tumors in 1235 ablation sessions: a 15-year experience.

OBJECTIVES: To assess the frequency of major complications after multi-probe stereotactic radiofrequency ablation (SRFA) in a large cohort of patients over 15 years and to elucidate risk factors for adverse events. MATERIALS AND METHODS: A retrospective study was carried out between July 2003 and December 2018. Seven hundred ninety-three consecutive patients (median 65.0 years (0.3-88), 241 women and 552 men, were treated in 1235 SRFA sessions for 2475 primary and metastatic liver tumors with a median tumor size of 3.0 cm (0.5-18 cm). The frequency of major complications was evaluated according to SIR guidelines and putative predictors of adverse events analyzed using simple and multivariable logistic regression. RESULTS: Thirty-day mortality after SRFA was 0.5% (6/1235) with an overall major complication rate of 7.4% (91/1235). The major complication rate decreased from 11.5% (36/314) (before January 2011) to 6.0% (55/921) (p = 0.001). 50.5% (46/91) of major complications were successfully treated in the same anesthetic session by angiographic coiling for hemorrhage and chest tube insertion for pneumothorax. History of bile duct surgery/intervention, number of coaxial needles, and location of tumors in segment IVa or VIII were independent prognostic factors for major complications following multivariable logistic regression analysis. Simple logistic regression revealed the number of tumors, tumor size, location close to the diaphragm, tumor conglomerate, and segment VII as other significant predictors. CONCLUSION: SRFA of liver tumors is safe and can extend the treatment spectrum of conventional RFA. Adaptations over time combined with increasing experience resulted in a significant decrease in complications. KEY POINTS: • In 1235 ablation sessions in 793 patients over 15 years, we found a mortality rate of 0.5% (6/1235) and an overall major complication rate of 7.4%, which fell from 11.5 (36/314) to 6.0% (55/921, p = 0.001) after January 2011, likely due to procedural adaptations. • History of bile duct surgery/intervention (p = 0.013, OR = 3.290), number of coaxial needles (p = 0.026, OR = 1.052), and location of tumors in segment IVa (p = 0.016, OR = 1.989) or VIII (p = 0.038, OR = 1.635) were found to be independent prognostic factors. • Simple logistic regression revealed that number of tumors, tumor size, location close to the diaphragm, tumor conglomerates, and segment VII were other significant predictors of major complications.

Stereotactic Radiofrequency Ablation of Hepatocellular Carcinoma: a Histopathological Study in Explanted Livers.

This retrospective study was performed to evaluate the efficacy of three-dimensional (3D)-navigated multiprobe radiofrequency ablation (RFA) with intraprocedural image fusion for treatment of hepatocellular carcinoma (HCC) by histopathological examination. From 2009 to 2018, 97 patients (84 men, 13 women; median age, 60 years; range, 1-71) were transplanted after bridging therapy of 195 HCCs by stereotactic RFA (SRFA). The median interval between the first SRFA and transplantation was 6.8 months (range, 0-71). The rate of residual vital tissue (RVT) could be assessed in 188 of 195 lesions in 96 of 97 patients by histological examination of the explanted livers using hematoxylin and eosin (H&E) and Tdt-mediated UTP nick-end labeling (TUNEL) stains. Histopathological results were compared with the findings of the last computed tomography (CT) imaging before liver transplantation (LT). Median number and size of treated tumors were 1 (range, 1-8) and 2.5 cm (range, 1-8). Complete radiological response was achieved in 186 of 188 nodules (98.9%) and 94 of 96 patients (97.9%) and complete pathological response in the explanted liver specimen in 183 of 188 nodules (97.3%) and 91 of 96 patients (94.8%), respectively. In lesions ≥3 cm, complete tumor cell death was achieved in 50 of 52 nodules (96.2%). Residual tumor did not correlate with tumor size (P = 0.5). Conclusion: Multiprobe SRFA with intraprocedural image fusion represents an efficient, minimally invasive therapy for HCC, even with tumor sizes larger than 3 cm, and without the need of a combination with additional treatments. The results seem to justify the additional efforts related to the stereotactic approach.

Feasibility, safety, and long-term efficacy of stereotactic radiofrequency ablation for tumors adjacent to the diaphragm in the hepatic dome: a case-control study.

OBJECTIVES: Achievement of adequate treatment margins may be challenging when the target is either difficult to visualize, awkward to access, or situated adjacent to vulnerable structures. Treatment of tumors located close to the diaphragm in the hepatic dome is challenging for percutaneous radiofrequency (RF) ablation for these reasons. The purpose was to assess the feasibility, safety, and clinical outcome of multi-probe stereotactic RF ablation (SRFA) of liver tumors in the subdiaphragmatic area. METHODS: Between 2006 and 2018, 177 patients (82 HCCs, 6 ICCs, and 89 metastatic tumors) underwent SRFA of 238 tumors abutting the diaphragm in the hepatic dome. For comparison, 177 patients were randomly selected from our database by the R package "MatchIt" for propensity score matching to compare treatment safety and efficacy in this retrospective, single-center study. RESULTS: Median treated tumor size was 2.2 cm (range 0.5 to 10 cm). SRFA was primarily successful for 232/238 (97.5%) tumors. Five tumors were successfully retreated, resulting in a secondary technical efficacy rate of 99.6%. Local tumor recurrence developed in 21 of 238 tumors (8.8%). The major ablation complication rate was 10.7% (22 of 204). Twelve (55%) of 22 major complications could be successfully treated by the interventional radiologist in the same anesthesia session. There was no significant difference in adverse events or disease control rates between the subdiaphragmatic tumors and matched controls. CONCLUSIONS: SRFA is a safe and feasible option in the management of difficult-to-treat tumors abutting the diaphragm in the hepatic dome, with similar safety profile compared with matched controls. KEY POINTS: • RFA was primarily successful for 232/238 (97.5%) subdiaphragmatic dome tumors. Local tumor recurrence developed in 21 of 238 tumors (8.8%). • The major complication rate directly related to ablation of the hepatic dome tumors was 10.7% (22 of 204). 12/22 (55%) of major complications could be successfully treated in the same anesthesia session. • There was no significant difference in adverse events or disease control rates between the subdiaphragmatic tumors and matched controls.

Minimal ablative margin (MAM) assessment with image fusion: an independent predictor for local tumor progression in hepatocellular carcinoma after stereotactic radiofrequency ablation.

OBJECTIVES: To assess the minimal ablative margin (MAM) by image fusion of intraprocedural pre- and post-ablation contrast-enhanced CT images and to evaluate if it can predict local tumor progression (LTP) independently. Furthermore, to determine a MAM with which a stereotactic radiofrequency ablation (SRFA) can be determined successful and therefore used as an intraprocedural tool to evaluate treatment success. METHODS: A total of 110 patients (20 women, 90 men; mean age 63.7 ± 10.2) with 176 hepatocellular carcinomas were assessed by retrospective analysis of prospectively collected data. The MAM was determined through image fusion of intraprocedural pre- and post-ablation images using commercially available rigid imaging registration software. LTP was assessed in contrast-enhanced CTs or MR scans at 3-6-month intervals. RESULTS: The MAM was the only significant independent predictor of LTP (p = 0.036). For each millimeter increase of the MAM, a 30% reduction of the relative risk for LTP was found (OR = 0.7, 95% CI 0.5-0.98, p = 0.036). No LTP was detected in lesions with a MAM > 5 mm. The overall LTP rate was 9 of 110 (8.2%) on a patient level and 10 of 173 (5.7%) on a lesion level. The median MAM was 3.4 (1.7-6.9) mm. The mean overall follow-up period was 26.0 ± 10.3 months. CONCLUSIONS: An immediate assessment of the minimal ablative margin (MAM) can be used as an intraprocedural tool to evaluate the treatment success in patients treated with stereotactic RFA. A MAM > 5 mm has to be achieved to consider an ablation as successful. KEY POINTS: • An intraoperatively measured minimal ablative margin (MAM) > 5 mm correlates with complete remission. • MAM is the only significant independent predictor of LTP (OR = 0.7, 95% CI 0.5-0.98, p = 0.036) after stereotactic RFA of hepatocellular carcinoma. • Image fusion using commercially available rigid imaging registration software is possible, even though considerably complex. Therefore, improved (semi-)automatic fusion software is highly desirable.

Simultaneous Stereotactic Radiofrequency Ablation of Multiple (≥ 4) Liver Tumors: Feasibility, Safety, and Efficacy.

PURPOSE: To assess feasibility, safety, and clinical outcome of simultaneous stereotactic radiofrequency (RF) ablation of multiple (≥ 4) primary and metastatic liver tumors. MATERIALS AND METHODS: This retrospective observational study included 92 patients (29 women, 62 men), 35 with ≥ 4 hepatocellular carcinomas (HCCs) and 57 with ≥ 4 metastatic liver tumors at initial stereotactic RF ablation between 2005 and 2018. The median size of 178 HCCs and 371 metastases was 2.2 cm (range, 1.0-8.5 cm) and 3.0 cm (range, 0.5-13 cm), respectively. At initial stereotactic RF ablation, 17 (48.6%) patients with HCC and 19 (33.3%) with metastases had 4 liver tumors, 11 (31.4%) and 19 (33.3%) had 5 tumors, and 7 (20%) and 19 (33.3%) had ≥ 6 tumors. RESULTS: Major complications occurred in 2 of 35 ablations (5.4%) in patients with HCCs and in 7 of 63 (10%) with metastases. The primary technical efficacy rate (ie, successful initial ablation) was 100% (178/178) in HCCs and 98.8% (363/371) in metastases. Local recurrence was observed in 4 of 178 (2.2%) HCCs and in 17 of 371 (4.6%) metastases. Overall survival (OS) rates at 1, 3, and 5 years from the date of the first stereotactic RF ablation were 88.0%, 54.0%, and 30.4% for patients with HCCs with a median OS of 38.2 months and 86.1%, 53.1%, and 37.3% for patients with metastases with a median OS of 37.4 months. CONCLUSIONS: Stereotactic RF ablation is a feasible, safe, and efficacious option in simultaneous management of multiple primary and metastatic liver tumors.

Thermal ablation of CT 'invisible' liver tumors using MRI fusion: a case control study.

Purpose: To evaluate whether 'invisible' liver tumors on CT can be treated by stereotactic radiofrequency ablation (SRFA) using fusion of pre-ablation MRI.Methods: In this retrospective case-control study, 60 patients (14 with Hepatocellular carcinoma (HCC) and 46 with metastatic liver tumors) with CT 'invisible' lesions underwent SRFA using MRI-fusion between June 2005 and June 2018 ('fusion group'). For comparison, 60 patients who underwent SRFA without image fusion were selected using nearest neighbor propensity score matching ('control group'). Endpoints consisted of local tumor control, safety, overall and disease-free survival.Results: Major complications occurred in 6/69 ablations (8.7%) in the fusion group and in 6/89 ablations (6.7%) in the control group (p = 0.434). Primary technical efficacy rate (i.e., successful initial ablation) was 96.6% (28/29) for HCC and 97.9% (166/170) for metastatic disease in the fusion group and 100% (33/33) and 93.3% (184/194) in the control group, respectively (p = 0.468 and 0.064). Local recurrence (LR) was observed in 1/29 (3.5%) HCCs and in 6/170 metastases (4.0%) in the fusion group and 1/33 (3.0%) and 21/196 (10.7%) in the control group, respectively. The LR rate of metastasis in the control group was significantly higher (p = 0.007), although differences in OS and DFS did not reach statistical significance.Conclusions: Image fusion using pre-procedural MRI allows for ablation of CT-'invisible' liver tumors that are otherwise untreatable. Moreover, local oncological control was higher in metastatic liver tumors versus matched controls which suggests it could be useful tool for all stereotactic radiofrequency ablation procedures.

Can accurate evaluation of the treatment success after radiofrequency ablation of liver tumors be achieved by visual inspection alone? Results of a blinded assessment with 38 interventional oncologists.

OBJECTIVES: To assess the difficulties in the immediate judgment of treatment success after radiofrequency ablation (RFA) of liver tumors by visual inspection alone and to evaluate whether radiologist's expertise affects the resultant judgment. METHODS: Peri-interventional CT-scans of nine patients with nine hepatocellular carcinomas with known outcomes after RFA were presented to 38 participants from 14 different countries. In a total of 342 reads, all interventional oncologists assessed the pre- and immediate post-interventional CT-scans through conventional side-by-side juxtapositioning of images and judged whether complete ablation (i.e., technical success and technique efficacy) was achieved. Results were compared regarding expertise in percutaneous tumor ablation (>50 interventions performed). An 'overcall' was defined as insufficient ablation that was misjudged as sufficient, and an 'undercall' as an erroneous assessment of complete ablation. RESULTS: Overall 3.97 ± 1.27 out of 9 (44.1%) cases per radiologist were misjudged. The mean number of overcalls and undercalls per radiologist were 0.74 ± 0.50 out of 2 (37.0%), and 3.24 ± 1.28 out of 7 (46.3%), respectively. 18/38 (47.4%) participants had considerable experience in percutaneous tumor ablation, with such expertise having no significant influence on the results (overall: p = 0.70; overcalls: p = 0.87; undercalls: p = 0.75). CONCLUSIONS: Conventional side-by-side evaluation of treatment success after RFA of liver tumors by the juxtaposition of pre- and post-interventional CT-scans is very difficult for experienced radiologists. The implementation of advanced processing techniques such as rigid/non-rigid image fusion with the assessment of the periablational margin is thus likely needed in order to decrease errors and objectively evaluate technical success and predict technique efficacy of liver RFA.

Stereotactic radiofrequency ablation of a variety of liver masses in children.

BACKGROUND AND AIMS: Surgical resection is currently the cornerstone of liver tumor treatment in children. In adults radiofrequency ablation (RFA) is an established minimally invasive treatment option for small focal liver tumors. Multiprobe stereotactic RFA (SRFA) with intraoperative image fusion to confirm ablation margins allows treatment for large lesions. We describe our experience with SRFA in children with liver masses. METHODS: SRFA was performed in 10 patients with a median age of 14 years (range 0.5-17.0 years) suffering from liver adenoma (n = 3), hepatocellular carcinoma (n = 1), hepatoblastoma (n = 2), myofibroblastic tumor (n = 1), hepatic metastases of extrahepatic tumors (n = 2) and infiltrative hepatic cysts associated with alveolar echinococcosis (n = 1). Overall, 15 lesions with a mean lesion size of 2.6 cm (range 0.7-9.5 cm) were treated in 11 sessions. RESULTS: The technical success rate was 100%, as was the survival rate. No transient adverse effects higher than grade II (Clavien and Dindo) were encountered after interventions. The median hospital stay was 5 d (range 2-33 d). In two patients who subsequently underwent transplant hepatectomy complete ablation was histologically confirmed. Follow-up imaging studies (median 55 months, range 18-129 months) revealed no local or distant recurrence of disease in any patient. CONCLUSIONS: SRFA is an effective minimal-invasive treatment option in pediatric patients with liver tumors of different etiologies.

Stereotactic radiofrequency ablation of primary liver tumors in the caudate lobe.

BACKGROUND: The encasement of the caudate lobe by a vascular ring of large vessels may apart from the technical difficulties in needle placement increase the probability of local recurrence after thermal ablation due to cooling effects. This single-center retrospective study evaluates the results after multiprobe stereotactic radiofrequency ablation (SRFA) of hepatocellular carcinoma (HCC) in the caudate lobe. METHODS: Twenty patients underwent 24 multiple-probe SRFA sessions for the treatment of 24 HCCs in the caudate lobe. Eight of twenty patients had initially solitary tumors, the remaining 12 patients suffered from multifocal disease. RESULTS: The median tumor size was 1.5 cm (range: 1-8 cm). After a mean follow-up of 21 months one local recurrence in the caudate lobe was observed resulting in a local recurrence rate of 4.2% (1/24). The overall survival rates at 1, 3, and 5 years from the date of the first SRFA were 95%, 59%, and 44%, respectively, with a median overall survival of 51.3 months. The disease-free survival after SRFA was 48%, 24% and 24%, at 1, 3 and 5 years, respectively. One patient suffering from Child C liver cirrhosis died due to septic shock 26 days after SRFA and one postinterventional complication required minimal invasive interventional treatment. CONCLUSION: Multiprobe SRFA for HCC in the caudate lobe appears to be safe and feasible. The overall outcome is at least comparable to that of surgical resection, with low perioperative mortality and only minimal morbidity.

Locoregional ablative treatment of melanoma metastases.

Standard treatment of melanoma has been evolving rapidly over the last decade, with novel treatment approaches improving therapeutic outcome not only in early-stage disease but also in advanced stage metastatic patients. Despite the improvement of systemic therapy outcomes, the current treatment guidelines reflect the fact that locoregional treatment approaches can be beneficial in patients suffering from oligometastatic disease. Minimally invasive ablation techniques have been established as a therapeutic cornerstone in the management of liver tumors, representing a local curative, relatively low-risk procedure. Depending on the size and location of metastatic disease, and on the applied ablation and guidance technique, ablative treatment approaches are effective to treat metastases in solid organs such as the liver or lungs, effectively covering the entire tumor with the ablation zone including a safety margin (A0 ablation in analogy to R0 resection). However, only retrospective data and case reports on locoregional treatment of melanoma metastases are available up to now, and prospective evaluation of this therapeutic approach is warranted to evaluate the beneficial role in the treatment of metastatic melanoma patients.

Stereotactic radiofrequency ablation of subcardiac hepatocellular carcinoma: a case-control study.

Purpose: The purpose of this study is to evaluate the safety and efficacy of stereotactic radiofrequency ablation (SRFA) for the treatment of subcardiac hepatocellular carcinoma (HCC). Material and methods: From 2003 to 2018, 79 consecutive patients underwent 104 multi-probe SRFA sessions for the treatment of 114 subcardiac HCC with a median size of 2.5 cm (0.5-9.5 cm). The results were compared with a randomly selected control group of 79 patients with 242 HCC with a median size of 2.0 cm (0.5-12 cm) following SRFA in other (non-subcardiac) locations with propensity score matching. Results: The 95.6% of the tumors were successfully treated by the first ablation session (primary technical efficacy rate) and 99.1% after the second session (secondary technical efficacy rate). Local tumor recurrence developed in 8 nodules (7.0%). Major complication and perioperative mortality rates were 7.7% (8/104) and 1% (1/104), respectively. The overall survival (OS) rates from the date of the first SRFA with single subcardiac HCCs were 92%, 77% and 65% at 1, 3 and 5 years, respectively, with a median OS of 90.6 months. The disease-free survival (DFS) after SRFA was 75, 34 and 34%, at 1, 3 and 5 years, respectively, with a median DFS of 19.1 months. There was no statistically significant difference with the control group in terms of local tumor control, safety, OS and DFS. Conclusion: SRFA of subcardiac tumors is as safe and efficacious as when treating tumors remote from the heart.

Stereotactic Radiofrequency Ablation for Breast Cancer Liver Metastases.

PURPOSE: To evaluate outcomes in patients with liver metastases from breast cancer treated with stereotactic radiofrequency (RF) ablation. MATERIALS AND METHODS: A retrospective analysis of 29 stereotactic RF ablation treatment sessions in 26 consecutive patients with 64 biopsy-proven breast cancer liver metastases (BCLMs) was conducted. Patients were included only if systemic treatment failed and all visible BCLMs were treatable. RESULTS: Primary and secondary technical success rates were 96.9% (62 of 64) and 100%, respectively. There were no perioperative mortalities. Local recurrence was identified in 5 tumors (7.8%), with no significant differences among tumor sizes (P = .662): < 3 cm (9.3%), 3-5 cm (0%), and > 5 cm (8.3%). Median estimated overall survival (OS) from first stereotactic ablation treatment was 29.3 months ± 8.9 (95% confidence interval [CI], 11.9-46.8 mo; mean, 28.7 mo) after a median follow-up of 23.1 months (mean, 31.3 mo; range, 0.1-100.8 mo). No significant differences in OS (P = .223) were observed among tumor volumes < 50 cm3 (median, 84.9 mo ± 53.1; mean, 58.4 mo), 50-100 cm3 (median, 37.8 mo ± 5.7; mean, 36.3 mo), and > 100 cm3 (median, 17.1 mo ± 3.5; mean, 21.8 mo). Numbers of metastases did not affect estimated OS, with a median OS of 32.7 months ± 10.4 (mean, 35.8 mo) for single lesions vs 17.7 months ± 3.2 (mean, 25.9 mo) for 2/3 lesions and a mean of 68.4 months ± 17.23 for > 3 lesions (P = .113). CONCLUSIONS: Multiple-electrode stereotactic RF ablation proved to be a safe minimally invasive alternative to surgical liver resection in selected patients with BCLMs.

Systemic Hypotension Following Intravenous Administration of Nonionic Contrast Medium During Computed Tomography: Iopromide Versus Iodixanol.

BACKGROUND: In light of the increasing number of radiologic interventions performed under general anesthesia, the effects of contrast media (CM) on circulation and organ perfusion are of paramount importance. The objectives of this study were to systematically quantify effects on blood pressure, heart rate, and kidney function following intravenous administration of nonionic CM with normal and low osmolality. METHODS: In this controlled, double-blinded phase IV clinical trial, 40 consecutive patients were randomly assigned to receive repeated measures of either low-osmolar iopromide or iso-osmolar iodixanol. Normal saline solution (NSS) served as control. Blood pressure and heart rate were measured continuously from 1 minute before until 3 minutes after administration of CM and NSS. Urine output was recorded hourly. RESULTS: Administration of iopromide resulted in systemic hypotension lasting up to 300 seconds (105 ± 61 seconds) with the lowest mean arterial pressure of 39 mm Hg (56.7 ± 12.2 mm Hg). Iopromide caused a systolic/diastolic decrease of 31/26 mm Hg (P < .001), significant increase in heart rate (P = .042), and significant diuresis with a 2-fold higher per-hour urine output (P = .010). Administration of iodixanol and NSS had no significant influence on blood pressure (P > .640). CONCLUSIONS: Administration of low-osmolar iopromide was followed by a significant transient decrease in blood pressure and a rise in heart rate. Anesthetists and radiologists should be aware of these effects in patients in whom short episodes of disturbed tissue microcirculation may pose a clinical risk.

Effect of ultra-low doses, ASIR and MBIR on density and noise levels of MDCT images of dental implant sites.

OBJECTIVES: Differences in noise and density values in MDCT images obtained using ultra-low doses with FBP, ASIR, and MBIR may possibly affect implant site density analysis. The aim of this study was to compare density and noise measurements recorded from dental implant sites using ultra-low doses combined with FBP, ASIR, and MBIR. METHODS: Cadavers were scanned using a standard protocol and four low-dose protocols. Scans were reconstructed using FBP, ASIR-50, ASIR-100, and MBIR, and either a bone or standard reconstruction kernel. Density (mean Hounsfield units [HUs]) of alveolar bone and noise levels (mean standard deviation of HUs) was recorded from all datasets and measurements were compared by paired t tests and two-way ANOVA with repeated measures. RESULTS: Significant differences in density and noise were found between the reference dose/FBP protocol and almost all test combinations. Maximum mean differences in HU were 178.35 (bone kernel) and 273.74 (standard kernel), and in noise, were 243.73 (bone kernel) and 153.88 (standard kernel). CONCLUSIONS: Decreasing radiation dose increased density and noise regardless of reconstruction technique and kernel. The effect of reconstruction technique on density and noise depends on the reconstruction kernel used. KEY POINTS: • Ultra-low-dose MDCT protocols allowed more than 90 % reductions in dose. • Decreasing the dose generally increased density and noise. • Effect of IRT on density and noise varies with reconstruction kernel. • Accuracy of low-dose protocols for interpretation of bony anatomy not known. • Effect of low doses on accuracy of computer-aided design models unknown.