Preclinical assessment of a mathematical model for ablation zone prediction in thyroid laser ablation.

To develop and validate a 3D simulation model to calculate laser ablation (LA) zone size and estimate the volume of treated tissue for thyroid applications, a model was developed, taking into account dynamic optical and thermal properties of tissue change. For validation, ten Yorkshire swines were equally divided into two cohorts and underwent thyroid LA at 3 W/1,400 J and 3 W/1,800 J respectively with a 1064-nm multi-source laser (Echolaser X4 with Orblaze™ technology; ElEn SpA, Calenzano, Italy). The dataset was analyzed employing key statistical measures such as mean and standard deviation (SD). Model simulation data were compared with animal gross histology. Experimental data for longitudinal length, width (transverse length), ablation volume and sphericity were 11.0 mm, 10.0 mm, 0.6 mL and 0.91, respectively at 1,400 J and 14.6 mm, 12.4 mm, 1.12 mL and 0.83, respectively at 1,800 J. Gross histology data showed excellent reproducibility of the ablation zone among same laser settings; for both 1,400 J and 1,800 J, the SD of the in vivo parameters was ≤ 0.7 mm, except for width at 1,800 J, for which the SD was 1.1 mm. Simulated data for longitudinal length, width, ablation volume and sphericity were 11.6 mm, 10.0 mm, 0.62 mL and 0.88, respectively at 1,400 J and 14.2 mm, 12.0 mm, 1.06 mL and 0.84, respectively at 1,800 J. Experimental data for ablation volume, sphericity coefficient, and longitudinal and transverse lengths of thermal damaged area showed good agreement with the simulation data. Simulation datasets were successfully incorporated into proprietary planning software (Echolaser Smart Interface, Elesta SpA, Calenzano, Italy) to provide guidance for LA of papillary thyroid microcarcinomas. Our mathematical model showed good predictability of coagulative necrosis when compared with data from in vivo animal experiments.

Iliocaval and iliofemoral venous stenting for obstruction secondary to tumor compression.

BACKGROUND: Cancer patients with pelviabdominal masses can suffer from lower extremity symptoms due to venous compression. The effectiveness of venous stenting has been established in extrinsic venous compression in benign conditions like May-Thurner syndrome. In this retrospective study we evaluate the efficacy and safety of caval, iliocaval and iliofemoral venous stenting for cases of extrinsic venous compression caused by malignant masses in cancer patients. METHODS: IRB-approved retrospective review of patients who underwent iliofemoral venography with venoplasty and stenting between January 2018 and February 2022 was performed. Patients with extrinsic venous compression caused by malignant masses were included. Data on patient demographics, pre-procedure symptoms, procedural technique, stent characteristics, outcomes and follow-up were collected. Descriptive statistics were used to assess technical success, clinical success, primary stent patency and adverse events of the procedure. RESULTS: Thirty-seven patients (19 males, 18 females) who underwent 45 procedures were included. Deep venous thrombosis (DVT) was present in 21 (57%) patients. Twenty-nine patients (78%, 95% CI 62-90%) reported clinical improvement of the presenting symptoms. The median overall survival after the procedure was 4.7 months (95% CI 3.58-5.99). Eight (22%) patients were alive at last follow up with median follow up of 10.33 months (Range 2-25 months). Twenty-six patients had patent stents on their last follow up imaging (70%, 95% CI 61%-91%). Two patients had a small access site hematoma which resolved spontaneously. Two patients developed moderate, and 1 patient developed severe adverse events related to post procedure therapeutic anticoagulation. CONCLUSION: Venous stenting is a safe procedure and should be considered as part of the palliative care for patients with debilitating lower extremity symptoms related to iliocaval and iliofemoral venous compression.

Iliocaval and Iliofemoral Venous Stenting for Obstruction Secondary to Tumor Compression: Single Center Experience.

Background: Cancer patients with pelviabdominal masses can suffer from lower extremity symptoms due to venous compression. The effectiveness of venous stenting has been established in extrinsic venous compression in benign conditions like May-Thurner syndrome. In this retrospective study we evaluate the efficacy and safety of caval, iliocaval and iliofemoral venous stenting for cases of extrinsic venous compression caused by malignant masses in cancer patients. Methods: IRB-approved retrospective review of patients who underwent iliofemoral venography with venoplasty and stenting between January 2018 and February 2022 was performed. Patients with extrinsic venous compression caused by malignant masses were included. Data on patient demographics, pre-procedure symptoms, procedural technique, stent characteristics, outcomes and follow-up were collected. Descriptive statistics were used to assess technical success, clinical success, primary stent patency and adverse events of the procedure. Results: Thirty-seven patients (19 males, 18 females) who underwent 45 procedures were included. Deep venous thrombosis (DVT) was present in 21 (57%) patients. Twenty-nine patients (78%, 95% CI 62-90%) reported clinical improvement of the presenting symptoms. The median overall survival after the procedure was 4.7 months (95% CI 3.58-5.99). Eight (22%) patients were alive at last follow up with median follow up of 10.33 months (Range 2-25 months). Twenty-six patients had patent stents on their last follow up imaging (70%, 95% CI 61%-91%). Two patients had a small access site hematoma which resolved spontaneously. Two patients developed moderate, and 1 patient developed severe adverse events related to post procedure therapeutic anticoagulation. Conclusion: Venous stenting is a safe procedure and should be considered as part of the palliative care for patients with debilitating lower extremity symptoms related to iliocaval and iliofemoral venous compression.

A comparison of lymphatic embolization and sclerotherapy in the management of iatrogenic abdominopelvic lymphoceles following oncological surgery.

PURPOSE: To compare the safety and efficacy of sclerotherapy and lymphatic embolization (LE) in the treatment of symptomatic iatrogenic lymphoceles following the placement of a percutaneous drainage catheter. METHODS: This is a retrospective study of 46 patients who underwent sclerotherapy (17 patients) or LE (29 patients) for the management of symptomatic iatrogenic lymphoceles following percutaneous drain placement between January 2017 and December 2021. The demographic characteristics, time between surgery and lymphatic intervention, clinical presentation, number of procedures, drain output pre- and post-intervention, time from intervention to drain removal, and adverse events were collected and compared for both groups. The clinical success rate, defined as the successful removal of the drain after one procedure, was calculated. Adverse events were reported according to the Society of Interventional Radiology classification. A statistical analysis was conducted using SPSS, and the P value for statistical significance was set at 0.05. The Mann-Whitney U test was used to compare differences in the scale variables, and Fisher's exact test was used to compare the categorical and ordinal variables between both groups. RESULTS: A total of 46 patients with 49 lymphoceles met the inclusion criteria of the study. Of these patients, 17 patients (19 lymphoceles) underwent sclerotherapy, and 29 patients (30 lymphoceles) underwent LE as their initial procedures. The clinical success after one procedure was significantly higher (83% vs. 47%, P = 0.011), and the median time between the first intervention and drain removal was significantly shorter in the LE group (median duration of 6 vs. 13 days, P = 0.018) compared with the sclerotherapy group. No statistically significant difference in adverse events was noted between both groups (0.26 vs. 0.10, P = 0.11). CONCLUSION: This study found that LE had a higher clinical success rate after the first procedure and a shorter time to drain removal compared with sclerotherapy. There was no difference in the rate of adverse events between both groups. Although LE is a safe and promising technique, a prospective study is needed to further compare the efficacy of both treatment modalities.

Percutaneous ablation of low-risk papillary thyroid cancer.

Abstract: Minimalistic management options such as active surveillance and thyroid lobectomy are increasingly being accepted as reasonable management options for properly selected patients with low-risk papillary thyroid cancer. Leveraging technologies developed for the treatment of benign thyroid nodules, ultrasound-guided percutaneous thermal ablation is now being evaluated as a potential additional minimalistic management option for small, intrathyroidal, low-risk papillary thyroid cancer. Published retrospective data on more than 5000 low-risk papillary thyroid cancer patients treated with thermal ablation indicate that with appropriate training and proper patient selection, these technologies can be safely and effectively applied to papillary microcarcinomas. When compared to immediate surgery, thermal ablation appears to have lower complication rates with similar short-term rates of recurrence. Proper patient selection is facilitated by the use of a clinical framework which integrates imaging characteristics, patient characteristics, and medical team characteristics to classify a patient as ideal, appropriate, or inappropriate for minimalistic management options (active surveillance, thyroid lobectomy, or thermal ablation). While retrospective in nature and lacking randomized prospective clinical trial data, currently available data do support the proposition that thermal ablation technologies reliably destroy papillary thyroid microcarcinoma lesions and are associated with clinically acceptable oncologic outcomes when done by experienced teams in properly selected patients.

Genomic heterogeneity as a barrier to precision oncology in urothelial cancer.

Precision oncology relies on the accurate molecular characterization of individual patients with cancer at the time of treatment initiation. However, tumor molecular profiles are not static, and cancers continually evolve because of ongoing mutagenesis and clonal selection. Here, we performed genomic analyses of primary tumors, metastases, and plasma collected from individual patients to define the concordance of actionable genomic alterations and to identify drivers of metastatic disease progression. We observed a high degree of discordance of actionable genomic alterations, with 23% discordant between primary and metastatic disease sites. Among chromatin-modifying genes, ARID1A mutations, when discordant, were exclusive to the metastatic tumor samples. Our findings indicate that the high degree of lesion-to-lesion genomic heterogeneity may be a barrier to precision oncology approaches for bladder cancer and that circulating tumor DNA profiling may be preferred to tumor sequencing for a subset of patients.

Percutaneous Image-Guided Biopsy for a Comprehensive Hybridization Capture-Based Next-Generation Sequencing in Primary Lung Cancer: Safety, Efficacy, and Predictors of Outcome.

Introduction: To evaluate factors associated with successful comprehensive genomic sequencing of image-guided percutaneous needle biopsies in patients with lung cancer using a broad hybrid capture-based next-generation sequencing assay (CHCA). Methods: We conducted a single-institution retrospective review of image-guided percutaneous transthoracic needle biopsies from January 2018 to December 2019. Samples with confirmed diagnosis of primary lung cancer and for which CHCA had been attempted were identified. Pathologic, clinical data and results of the CHCA were reviewed. Covariates associated with CHCA success were tested for using Fisher's exact test or Wilcoxon ranked sum test. Logistic regression was used to identify factors independently associated with likelihood of CHCA success. Results: CHCA was requested for 479 samples and was successful for 433 (91%), with a median coverage depth of 659X. Factors independently associated with lower likelihood of CHCA success included small tumor size (OR = 0.26 [95% confidence interval (CI): 0.11-0.62, p = 0.002]), intraoperative inadequacy on cytologic assessment (OR = 0.18 [95% CI: 0.06-0.63, p = 0.005]), small caliber needles (≥20-gauge) (OR = 0.22 [95% CI: 0.10-0.45, p < 0.001]), and presence of lung parenchymal abnormalities (OR = 0.12 [95% CI: 0.05-0.25, p < 0.001]). Pneumothorax requiring chest tube insertion occurred in 6% of the procedures. No grade IV complications or procedure-related deaths were reported. Conclusions: Percutaneous image-guided transthoracic needle biopsy is safe and has 91% success rate for CHCA in primary lung cancer. Intraoperative inadequacy, small caliber needle, presence of parenchymal abnormalities, and small tumor size (≤1 cm) are independently associated with likelihood of failure.

Augmented fluoroscopy guided transbronchial pulmonary microwave ablation using a steerable sheath.

Background: Transbronchial microwave ablation (MWA) is a promising novel therapy. Despite advances in bronchoscopy and virtual navigation, real time image guidance of probe delivery is lacking, and distal maneuverability is limited. Cone-beam computed tomography (CBCT) based augmented fluoroscopy guidance using steerable sheaths may help overcome these shortcomings. The aim of this study was to evaluate feasibility and accuracy of augmented fluoroscopy guided transbronchial MWA with a steerable sheath and without a bronchoscope. Methods: In this prospective study, procedures were performed under general anesthesia. Extra-bronchial lung synthetic targets were placed percutaneously. Target and airways extracted from CBCT, with planned bronchial parking point close to the target were overlaid on live fluoroscopy. Endobronchial navigation was solely performed under augmented fluoroscopy guidance. A 6.5 Fr steerable sheath was parked in the bronchus per plan, and a flexible MWA probe was inserted coaxially then advanced through the bronchus wall towards the target. Final in-target position was confirmed by CBCT. Only one ablation of 100 W-5 min was performed per target. Animals were euthanized and pathology analysis of the lungs was performed. Results: Eighteen targets with a median largest diameter of 9 mm (interquartile range, 7-11 mm) were ablated in 9 pigs. Median needle-target center distance was 2 mm (interquartile range, 0-4 mm), and was higher for lower/middle than for upper lobes [0 mm (interquartile range, 0-4 mm) vs. 4 mm (interquartile range, 3-8 mm), P=0.04]. No severe complications or pneumothorax occurred. Two cases of rib fractures in the ablation zone resolved after medical treatment. Median longest axis of the ablation zone on post-ablation computed tomography was 38 mm (interquartile range, 30-40 mm). Histology showed coagulation necrosis of ablated tissue. Conclusions: Transbronchial MWA under augmented fluoroscopy guidance using a steerable sheath is feasible and accurate.

Accuracy of a CBCT-based virtual injection software for vessel detection during hepatic arterial embolization.

PURPOSE: To assess the accuracy, sensitivity, positive predictive value (PPV) and interobserver agreement of a virtual injection (VI) software that simulates selective arterial injection from nonselective cone-beam CT (CBCT) arteriography. METHODS: From March 2019 to May 2020, 20 consecutive patients in whom a nonselective injected CBCT and a selective CT angiography (CTA) were completed in the same procedure, were retrospectively included. The position of the microcatheter tip used for selective CTA injection was identified. The VI was simulated from the exact same point on the nonselective CBCT and the two volumes were merged. VI was compared to the real injection on the selective CTA. Three interventional radiologists evaluated the accuracy using a 6-point scale (Perfect; Good; Fair; Incorrect Origin; False Negative; Non existing). Sensitivity, PPV, and Fleiss' kappa were calculated. Numerical variables were presented as means ± standard deviations. RESULTS: Twenty procedures and 195 vessel segments were analyzed. Most vessels were 4th order (57/195; 29%) and 5th order (96/195; 49%). VI was classified as perfect to good in 96.8% ± 1.4 of 1st-3rd order arteries and in 83.4% ± 0.4 of 4th-5th order arteries. Interobserver agreement was substantial (Fleiss' kappa = 0.79; 95% confidence interval = 0.73-0.84, P < 0.01). False negatives were reported with a mean of 9.4% ± 0.3. Average sensitivity was 90.6% ± 0.3 and average PPV was 92.7% ± 0.02. Fourteen false positives were noted. CONCLUSION: CBCT-based VI software accurately simulated distal injections in the liver with high sensitivity and a substantial interobserver agreement.

Percutaneous liver venous deprivation: outcomes in heavily pretreated metastatic colorectal cancer patients.

BACKGROUND: To evaluate liver venous deprivation (LVD) outcomes in patients with colorectal liver metastasis (CRLM) heavily pretreated with systemic and hepatic arterial infusion pump (HAIP) chemotherapies that had an anticipated insufficient future liver remnant (FLR) hypertrophy after portal vein embolization (PVE). METHODS: PVE was performed with liquid embolics using a transsplenic or ipsilateral transhepatic approach. Simultaneously and via a trans-jugular approach, the right hepatic vein was embolized with vascular plugs. Liver volumetry was assessed on computed tomography before and 3-6 weeks after LVD. RESULTS: Twelve consecutive CRLM patients that underwent LVD before right hepatectomy or trisectionectomy were included, all previously treated with systemic chemotherapy for a mean of 11.9 months. Six patients had additional HAIP. After embolization, FLR ratio increased from 28.7% ± 5.9 to 42.2% ± 9.0 (P < 0.01). Mean kinetic growth rate (KGR) was 3.56%/week ± 2.3, with a degree of hypertrophy (DH) of 13.8% ± 7.1. In the HAIP subgroup, mean KGR and DH were respectively 3.58%/week ± 2.8 and 14.3% ± 8.7. No severe complications occurred. Ten patients reached surgery after 39 days ± 7.5. CONCLUSION: In heavily pretreated patients, LVD safely stimulated a rapid and effective FLR hypertrophy, with a resultant high rate of resection.

Ablation Zone Involution of Liver Tumors Is Faster in Patients Treated with Irreversible Electroporation Than Microwave Ablation.

Background and Objectives: To compare ablation zone involution following microwave ablation (MWA) or irreversible electroporation (IRE) of liver tumors. Materials and Methods: MWA or IRE performed for colorectal cancer liver metastasis (CRLM) or hepatocellular carcinoma (HCC) during January 2011 to December 2015 were analyzed. Patients with a tumoral response on 1-year follow-up computed tomography (CT) were included. Generalized estimating equations were used to evaluate the differences between the two modalities on ablation zone involution observed on CT at 6 (M6) and 12 months (M12), and on laboratory values (total bilirubin, alanine transaminase, aspartate transaminase, alkaline phosphatase, albumin, and platelets count). The likelihood ratio test was used to assess whether the association between ablation modalities and these outcomes differed over time. Results: Seventeen (17/44, 39%) women and 27 (27/44, 61%) men were included, with 25 HCC (25/44, 57%) and 19 CRLM (19/44, 43%) patients. IRE was used in 9 (9/19, 47%) CRLM and 5 (5/25, 20%) HCC patients, respectively. All other patients had MWA. Ablation zone size and involution between IRE and MWA differed significantly over time (interaction p < 0.01), with a mean of 241.04 vs. 771.08 mm2 (ratio 0.313; 95% CI, 0.165-0.592; p < 0.01) at M6 and 60.47 vs. 589.43 mm2 (ratio 0.103; 95% CI, 0.029-0.365; p < 0.01) at M12. Changes in liver enzymes did not differ significantly between IRE and MWA at both timepoints. Conclusions: Liver tumors treated with IRE underwent faster involution when compared to tumors treated with MWA, but liver enzymes levels were comparable.

Percutaneous Lymphatic Embolization as Primary Management of Pelvic and Retroperitoneal Iatrogenic Lymphoceles.

PURPOSE: To evaluate the efficacy of lymphatic embolization (LE) in decreasing catheter output and dwell time in iatrogenic lymphoceles after percutaneous catheter drainage. MATERIALS AND METHODS: Retrospective review of patients who underwent intranodal lymphangiography (INL) with or without LE for management of iatrogenic lymphoceles between January 2017 and November 2020 was performed. Twenty consecutive patients (16 men and 4 women; median age, 60.5 years) underwent a total of 22 INLs and 18 LEs for 15 pelvic and 5 retroperitoneal lymphoceles. Lymphatic leaks were identified in 19/22 (86.4%) of the INLs. Three patients underwent INL only because a leak was not identified or was identified into an asymptomatic lymphocele. One patient underwent repeat INL and LE after persistent high catheter output, and 1 patient underwent repeat INL with LE after the initial INL did not identify a leak. Catheter output was assessed until catheter removal, and changes in output before and after the procedure were reported. The patients were followed up for 2-30 months, and procedural complications were reported. RESULTS: The median catheter output before the procedure was 210 mL/day (50-1,200 mL/day), which decreased to a median of 20 mL/day (0-520 mL/day) 3 days after the procedure, with a median output decrease of 160 mL (0-900 mL). The median time between INL with LE and catheter removal was 6 days, with no recurrence requiring redrainage. Four patients experienced minor complications of low-grade fever (n = 2) and lower limb edema (n = 2). CONCLUSIONS: Lymphangiogram and LE are safe and effective methods for the management of lymphoceles.

Ultrasound-Guided Percutaneous Laser Ablation of the Thyroid Gland in a Swine Model: Comparison of Ablation Parameters and Ablation Zone Dimensions.

BACKGROUND: To compare laser ablation (LA) zone dimensions at two predetermined energy parameters to cover a theoretical 10 mm zone + 2 mm margin in a thyroid swine model. METHODS: Approval of the Institutional Animal Care and Use Committee was obtained. After hydrodissection, an ultrasound-guided LA (Elesta Echolaser X4 with Orblaze technology, 1064 nm) was performed in the periphery of the thyroid in 10 swine. Two cohorts were established to ablate a region of 10mm diameter with 2mm margin based on manufacturer's ex vivo data (n= 5 at 3W/1400J and n= 5 at 3W/1800J). The ablation zone was measured on contrast-enhanced computed tomography (CT) and compared to the pathological specimen. Euthanasia was performed 48 hours following ablation. RESULTS: All ablations in the 3W/1800J group achieved a diameter of 12 mm ± 1 mm in three dimensions. In the 3W/1400J group, 1 ablation reached 12 mm ± 1 mm in 2 dimensions and 4 ablations reached this size in one dimension. Maximum diameter was higher in the 3W/1800J compared to the 3W/1400J group, both on histology (1.46 cm ± 0.05 vs. 1.1 cm ± 0.0, p< 0.01) and CT (1.52 cm ± 0.04 vs. 1.18 cm ± 0.04, p< 0.01). Similar results were obtained regarding volumes, both on histology (1.12 mL ± 0.13 vs. 0.57 mL ± 0.06, p< 0.01) and CT (1.24 mL ± 0.13 vs. 0.59 mL ± 0.07, p< 0.01). Histology showed coagulation necrosis and correlated well with CT measurements. CONCLUSION: Optimal parameters to obtain a LA zone of 10 mm with 2 mm margin utilizing a single needle are 3W/1800J.

Diagnostic Value of Extracellular Volume Quantification and Myocardial Perfusion Analysis at CT in Cardiac Amyloidosis.

Background CT can provide information regarding myocardial perfusion and expansion of the extracellular space, which is relevant to patients with cardiac amyloidosis (CA). Purpose To evaluate the role of CT in the diagnosis and prognosis of CA. Materials and Methods In this prospective study (Commission National de l'Informatique et des Libertés registration no. 1431858), participants with CA, participants with nonamyloid cardiac hypertrophy (NACH), and participants without hypertrophy were included between April 2017 and December 2018. The confirmed diagnosis of CA was determined according to established criteria (ie, proven with positive bone scintigraphy or endomyocardial biopsy). All participants were imaged with dynamic CT perfusion imaging at whole-heart cardiac CT. Extracellular volume measured at CT and myocardial perfusion parameters calculated on CT perfusion maps were compared among different participant groups. Differences between continuous data were tested using the unpaired t test, Mann-Whitney rank-sum test, or the Kruskal-Wallis test. Results A total of 84 participants with CA, 43 participants with NACH, and 33 participants without hypertrophy were included. Participants with CA exhibited a higher value of extracellular volume measured at CT (mean, 54.7% ± 9.7 [standard deviation]) than participants with NACH (mean, 34.6% ± 9.1; P < .001) and participants without hypertrophy (mean, 35.9% ± 9.9; P = .001). Mean myocardial blood volume and mean myocardial blood flow were lower in participants with CA (mean myocardial blood volume: 4.05 mL/100 g of myocardium ± 0.80; mean myocardial blood flow: 73.2 mL/100 g of myocardium per minute ± 25.7) compared to participants with NACH (mean myocardial blood volume: 5.38 mL/100 g of myocardium ± 1.20, P < .001; mean myocardial blood flow: 89.6 mL/100 g of myocardium per minute ± 31.3, P = .007) and participants without hypertrophy (mean myocardial blood volume: 5.68 mL/100 g of myocardium ± 1.05; mean myocardial blood flow: 106.3 mL/100 g of myocardium per minute ± 29.8; P < .001 for both). Extracellular volume measured at CT (hazard ratio >0.56 vs ≤0.56 = 4.2 [95% CI: 1.4, 11.8]), mean slope (hazard ratio ≤3.0 sec-1 vs >3.0 sec-1 = 0.2 [95% CI: 0.1, 0.8]), and time to peak (hazard ratio >20 seconds vs ≤20 seconds = 11.6 [95% CI: 1.3, 101.6]) were predictive of mortality in participants with CA. Conclusion Participants with cardiac amyloidosis exhibited an increase in extracellular volume at CT and abnormal CT perfusion parameters. Extracellular volume and several perfusion parameters were predictive of mortality. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Zimmerman in this issue.

Retrospective Use of Breathing Motion Compensation Technology (MCT) Enhances Vessel Detection Software Performance.

PURPOSE: Cone beam CT (CBCT) with planning software is used in intra-arterial liver-directed therapies. Software accuracy relies on high CBCT image quality, which can be impaired by breathing motion. We assessed the impact of a specific MCT on software performance for procedure planning and navigation. MATERIALS AND METHODS: Institutional Review Board (IRB)-approved retrospective evaluation of liver-directed therapies from July 2015 to April 2018 was performed. CBCTs with at least one well-defined tumor and noticeable breathing motion were included. Each CBCT was reconstructed with and without breathing MCT (Motion Freeze, GE Healthcare). Automatic tumor-supplying vessel detection was performed on up to 4 tumors in each CBCT reconstruction (Liver ASSIST V.I., GE Healthcare). Vessel detection sensitivity and positive predictive value (PPV) were measured with and without MCT using Digital Subtracted Angiography (DSA) as reference. Preprocedural contrast-enhanced CT was also utilized in some cases to rule out the possibility of extrahepatic supplying vessels. RESULTS: MCT was applied retrospectively to 18 CBCTs with a total of 30 tumors. At least one supplying vessel was detected for 28/30 (93%) tumors with MCT versus 20/30 (66%) without. On the subgroup of 10 CBCTs (22 tumors, 76 feeders) in which the automatic vessel detection initially worked in both reconstructions, the average sensitivity and PPV increased from 63% (48/76) and 57% (48/84) before MCT to 83% (63/76) and 79% (63/80) after (p = 0.002 and p < 0.001). CONCLUSION: Breathing MCT improves planning software performance in CBCT impaired by breathing motion.

Relationship of radiation dose to efficacy of radioembolization of liver metastasis from breast cancer.

PURPOSE: To determine the relationship of tumoral and nontumoral radiation dose to response and toxicity after transarterial radioembolization (TARE) of breast cancer liver metastasis. METHODS: This retrospective study evaluated all patients with breast cancer liver metastases treated with TARE (2/2011-6/2019). Extent of disease was measured as unilobar or bilobar on baseline PET/CT prior to TARE. Response was assessed for targeted regions with modified PERCIST criteria on first follow-up PET/CT. Tumoral and nontumoral liver dosimetry was evaluated by performing volumetric segmentation on post-TARE Bremsstrahlung SPECT/CT. ≥Grade 3 hepatotoxicity was defined as ≥grade 3 bilirubin/AST/ALT elevation or ascites requiring intervention. Fisher's exact tests, Wilcoxon rank sum tests, and Kaplan-Meier survival analysis were performed. RESULTS: Among 64 women, 60 patients had pre- and post-TARE PET/CT, of whom 46/60 (77 %) achieved objective response (OR). Responders received higher tumoral dose with a median (interquartile range) of 167 (96-217) vs. 54 (45-62) Gy (p < 0.001). ≥Grade 3 hepatotoxicity occurred in 8/64 (12.5 %) and was associated with higher pre-treatment bilirubin levels of 0.9 (0.9-1.1) vs. 0.5 (0.4-0.7) mg/dL (p = 0.013). Median overall survival (OS) was 11 (95 % CI 10-19) months. Bilobar disease (Hazard Ratio [HR]: 2.77, 95 % CI 1.11-6.89, p = 0.028) and elevated pre-TARE AST (HR 1.02, 95 % CI 1.01-1.03, p < 0.001) were independently associated with shorter survival. ≥Grade 3 hepatotoxicity was associated with reduced survival (p < 0.001). OR was associated with longer OS of 17 months, compared with 10 months (p = 0.027). CONCLUSION: In TARE for breast cancer liver metastasis, higher tumoral radiation dose (>79.5 Gy) was associated with OR, which was associated with longer survival. Pre-existing liver dysfunction was associated with hepatotoxicity, which was associated with decreased survival.

Predictors of Progression-Free Survival and Local Tumor Control after Percutaneous Thermal Ablation of Oligometastatic Breast Cancer: Retrospective Study.

PURPOSE: To describe ablation of bone, liver, lung, and soft tissue tumors from oligometastatic breast cancer and to define predictors of local progression and progression-free survival (PFS). MATERIALS AND METHODS: A total of 33 women (mean age 52 ± 12 years old; range, 28-69 years), underwent 46 thermal ablations of liver (n = 35), lung (n = 7), and bone/soft tissue (n = 4) metastases. Mean tumor diameter was 18 ± 15 mm (range, 6-50 mm). Ablations were performed to eradicate all evident sites of disease (n = 24) or to control growing sites in the setting of other stable or responding sites of disease (n = 22). Patient characteristics, ablation margins, imaging responses, and cases of PFS were assessed. Follow-up imaging was performed using contrast-enhanced computed tomography (CT), magnetic resonance (MR) imaging, or positron-emission tomography/ CT. RESULTS: Median PFS was 10 months (95% confidence interval [CI], 6.2 -14.5 months), and time to local progression was 11 months (95% CI, 5-16 months). Eight patients (24%) maintained no evidence of disease during a median follow-up period of 39 months. Ablation margin ≥5 mm was associated with no local tumor progression. Longer PFS was noted in estrogen receptor-positive patients (12 vs 4 months; P = .037) and younger patients (12 vs 4 months; P = .039) treated to eradicate all sites of disease (13 vs 5 months; P = .05). Eighteen patients (55%) developed new metastases during study follow-up. CONCLUSIONS: Thermal ablation of oligometastatic pulmonary, hepatic, bone, and soft tissue tumors can eliminate local tumor progression if margins are ≥5 mm. Longer PFS was observed in patients who were estrogen receptor-positive and patients who were younger and in whom all sites of disease were eradicated.

PET/CT Imaging Characteristics After Radioembolization of Hepatic Metastasis from Breast Cancer.

PURPOSE: To define positron emission tomography/computed tomography (PET/CT) imaging characteristics during follow-up of patients with metastatic breast cancer (MBC) treated with yttrium-90 (Y90) radioembolization (RE). MATERIALS AND METHODS: From January 2011 to October 2017, 30 MBC patients underwent 38 Y90 glass or resin RE treatments. Pre-RE PET/CT was performed on average 51 days before RE. There were 68 PET/CTs performed after treatment. Response was assessed using modified PERCIST criteria focusing on the hepatic territory treated with RE, normalizing SUVpeak to the mean SUV of liver uninvolved by tumor. An objective response (OR) was defined as a decrease in SUVpeak by at least 30%. RESULTS: Of the 68 post-RE scans, 6 were performed at 0-30 days, 15 at 31-60 days, 9 at 61-90 days, 13 at 91-120 days, 14 scans at 121-180 days, and 11 scans at > 180 days after RE. Of the 30 patients, 25 (83%) achieved OR on at least one follow-up. Median survival was 15 months after the first RE administration. Highest response rates occurred at 30-90 days, with over 75% of cases demonstrating OR at that time. After 180 days, OR was seen in only 25%. There was a median TTP of 169 days among responders. CONCLUSION: In MBC, follow-up PET/CT after RE demonstrates optimal response rates at 30-90 days, with progression noted after 180 days. These results help to guide the timing of imaging and also to inform patients of expected outcomes after RE.

Percutaneous image-guided ablation: From techniques to treatments.

Image-guided ablation is performed by percutaneously introducing ablation probes to deliver energy into a tumor to destroy it in a controlled and localized fashion. Ablation modalities can be broadly classified as thermal or non-thermal based on the mechanism of tumor destruction and are performed using different types of image guidance for planning, delivering and follow-up of the treatment. Ablation is performed in a minimally invasive fashion, providing greater residual organ preservation with minimal morbidity to the patient. Image-guided ablation is being used in the clinic for the treatment of primary and metastatic tumors, and this article reviews state of the art for the treatment of malignancies in the liver, lung, kidney and musculoskeletal tissue.