Safety and Efficacy of Retrograde Pyeloperfusion for Ureteral Protection during Renal Tumor Cryoablation

PurposeTo determine safety and efficacy of retrograde pyeloperfusion for ureteral protection during cryoablation of adjacent renal tumors.Materials and MethodsRetrospective review of 155 patients treated with renal cryoablation, including adjunctive retrograde pyeloperfusion, from 2005 to 2019 was performed. Ice contacted the ureter in 67 of the 155 patients who represented the study cohort. Median patient age was 68 years old (interquartile range [61, 74]), 52 patients (78%) were male, and 37 tumors (55%) were clear cell histology. Mean tumor size was 3.4 ± 1.3 cm, and 42 tumors (63%) were located at the lower pole. Treatment-related complication and oncologic outcomes were recorded based on a review of post-procedural images and chart review.ResultsTechnical success of cryoablation was attained in 67 cases (100%), and technical success of pyeloperfusion was attained in 66 cases (99%). A total of 13 patients (19.4%) experienced SIR major C or D complications related to the procedure, including hemorrhage (n = 4), urine leak (n = 3), transient urinary obstruction (n = 2), pulmonary embolism (n = 1), hypertensive urgency (n = 1), acute respiratory failure (n = 1), and ureteropelvic junction (UPJ) stricture (n = 1). No complications were attributable to pyeloperfusion. Three of 45 patients with biopsy-proven renal cell carcinoma experienced local recurrence resulting in local recurrence-free survival of 92% (95% confidence interval, 81.5%–100%) 3 years after ablation.ConclusionsRetrograde pyeloperfusion of the renal collecting system is a relatively safe and efficacious option for ureteral protection during renal tumor cryoablation. This adjunctive procedure should be considered for patients in whom cryoablation of a renal mass could potentially involve the ureter.     

Stereotactic Body Radiotherapy for Stage I Renal Cell Carcinoma: National Treatment Trends and Outcomes Compared to Partial Nephrectomy and Thermal Ablation

PurposeTo assess use of stereotactic body radiotherapy (SBRT) for stage I renal cell carcinoma (RCC) and compare outcomes with thermal ablation and partial nephrectomy (PN).Materials and MethodsThe 2004–2015 National Cancer Database was investigated for histopathologically proven stage I RCC treated with PN, cryoablation, radiofrequency (RF) or microwave (MW) ablation, or SBRT. Patients were propensity score–matched to account for potential confounders, including patient age, sex, race, comorbidities, tumor size, histology, grade, tumor sequence, administration of systemic therapy, treatment in academic vs nonacademic centers, treatment location, and year of diagnosis. Overall survival (OS) was evaluated with Kaplan-Meier plots, log-rank tests, and Cox proportional hazards models.ResultsA total of 91,965 patients were identified (SBRT, n = 174; PN, n = 82,913; cryoablation, n = 5,446; RF/MW ablation, n = 3,432). Stage I patients who received SBRT tended to be older women with few comorbidities treated at nonacademic centers in New England states. After propensity score matching, a cohort of 636 patients was obtained with well-balanced confounders between treatment groups. In the matched cohort, OS after SBRT was inferior to OS after PN and thermal ablation (PN vs SBRT, hazard ratio [HR] = 0.29, 95% confidence interval [CI] 0.19–0.46, P < .001; cryoablation vs SBRT, HR = 0.40, 95% CI 0.26–0.60, P < .001; RF/MW ablation vs SBRT, HR = 0.46, 95% CI 0.31–0.67, P < .001). Compared with PN, neither cryoablation nor RF/MW ablation showed significant difference in OS (cryoablation vs PN, HR = 1.35, 95% CI 0.80–2.28, P = .258; RF/MW ablation vs PN, HR = 0.64, 95% CI 0.95–2.55, P = .079).ConclusionsCurrent SBRT protocols show lower OS compared with thermal ablation and PN, whereas thermal ablation and PN demonstrate comparable outcomes.     

Percutaneous MR Imaging-Guided Laser Ablation and Cryoablation for the Treatment of Pediatric and Adult Symptomatic Peripheral Soft Tissue Vascular Anomalies

PurposeTo evaluate the safety and effectiveness of percutaneous magnetic resonance (MR) imaging-guided laser ablation and cryoablation for the treatment of symptomatic soft tissue vascular anomalies (VAs) of the trunk and extremities.Materials and MethodsAn institutional review board-approved retrospective review was undertaken of all pediatric and adult patients who underwent MR imaging-guided and monitored laser ablation and/or cryoablation for the treatment of symptomatic peripheral soft tissue VA. Preablation and postablation MR imaging was independently reviewed. Pain scores on the visual analog scale (0 to 10) and self-reported subjective symptomatic improvement were assessed. Change in VA size and pain scores were compared using a paired t test.ResultsThirty patients (24 females; age, 10–75 years) with 34 VAs were treated for moderate to severe pain (n = 27) or swelling/mass effect (n = 3) with 60 total ablation sessions. The baseline maximum VA diameter was 9.5 cm ± 8.6. At baseline, all VAs (100%) demonstrated variable T2-weighted signal hyperintensity and enhancement. The baseline pain score was 6.4 ± 1.6. Clinical follow-up was available for 23 patients. At a mean follow-up time of 12.2 months ± 10.1, 19 of 20 (95%) patients treated for pain and 2 of 3 (67%) patients treated for swelling/mass effect reported partial or complete symptomatic relief. There was a significant decrease in the postablation pain scores (−5.7 ± 1.0, P < .001) and maximum VA size (−2.3 cm ± 2.7, P = .004), with >50% reduction in VA T2 signal (59%) and enhancement (73%). Nine of 30 (30%) patients experienced minor complications.ConclusionsMR imaging-guided and monitored percutaneous laser ablation and cryoablation appear to be safe and effective for the treatment of symptomatic peripheral soft tissue VAs.     

Dual-Applicator MR Imaging–Guided Microwave Ablation with Real-Time MR Thermometry: Phantom and Porcine Tissue Model Experiments

PurposeTo investigate the effect of simultaneous use of dual applicators on the image quality of real-time magnetic resonance (MR) thermometry and to characterize the dual-applicator treatment zone pattern during MR imaging–guided microwave ablation (MWA).Materials and MethodsMWA experiments were performed on a 1.5-T MR scanner with 2 commercial microwave systems (902–928 MHz). Phantom experiments were first performed to evaluate the effect of dual-applicator MWA on the image quality of MR. Then, porcine tissue model experiments were conducted with real-time MR thermometry using either a single applicator or dual applicators inserted 2.6, 3.6, and 4.6 cm apart. Fiberoptic thermal probes were used to measure the temperature changes at the tissue surface.ResultsSimultaneous use of dual applicators resulted in a decrease in the relative signal-to-noise ratio (SNR) in the MR thermometry images to 55% ± 2.9% when compared with that of a single applicator (86.2% ± 2.0%). Despite the lower SNR, the temperature and ablation zone maps were of adequate quality to allow visualization of the ablation zone(s). The extents of increase in the temperature at the tissue surface using dual applicators (19.7 °C ± 2.6 °C) and a single applicator (18.2 °C ± 3.3 °C) were not significantly different (P = .40). Treatment zones were significantly larger (P < .05) in dual-applicator ablations (29.4 ± 0.4, 39.9 ± 0.6, and 42.6 ± 0.9 cm² with 2.6-, 3.6-, and 4.6-cm spacing, respectively) at the end of the ablation procedure than in the single-applicator MWA (18.6 ± 0.9 cm²).ConclusionsMR imaging–guided dual-applicator MWA produced larger ablation zones while allowing adequate real-time MR thermometry image quality for monitoring the evolution of the treatment zone.     

Juxtametallic Bipolar Bone Radiofrequency Ablation: Thermal Monitoring in an Ex-Vivo Model with Specimen MRI and Histopathologic Correlation

PurposeTo measure the ablation zone temperature and nontarget tissue temperature during radiofrequency (RF) ablation in bone containing metal instrumentation versus no metal instrumentation (control group).Materials and MethodsEx vivo experiments were performed on 15 swine vertebrae (control, n = 5; titanium screw, n = 5; stainless steel screw, n = 5). Screws and RF ablation probe were inserted identically under fluoroscopy. During RF ablation (3 W, 5 minutes), temperature was measured 10 mm from RF ablation centerpoint and in muscle contacting the screw. Magnetic resonance (MR) imaging, gross pathologic, and histopathologic analyses were performed on 1 specimen from each group.ResultsAblation zone temperatures at 2.5 and 5 minutes increased by 12.2 °C ± 2.6 °C and 21.5 °C ± 2.1 °C (control); 11.0 °C ± 4.1 °C and 20.0 °C ± 2.9 °C (juxta-titanium screw), and 10.0 °C ± 3.4 °C and 17.2 °C ± 3.5 °C (juxta–stainless steel) screw; differences among groups did not reach significance by analysis of variance (P = .87). Mixed-effects linear regression revealed a statistically significant increase in temperature over time in all 3 groups (4.2 °C/min ± 0.4 °C/min, P < .001). Compared with the control, there was no significant difference in the temperature change over time for titanium (?0.3 °C/min ± 0.5 °C/min, P = .53) or steel groups (?0.4 °C/min ± 0.5 °C/min, P = .38). The mean screw temperature at the final time point did not show a statistically significant change compared with baseline in either the titanium group (?1.2 °C ± 2.3 °C, P = .50) or steel group (2.6 °C ± 2.9 °C, P = .11). MR imaging and pathologic analyses revealed homogeneous ablation without sparing of the peri-hardware zones.ConclusionsAdjacent metallic instrumentation did not affect the rate of or absolute increase in temperature in the ablation zone, did not create peri–metallic ablation inhomogeneities, and did not result in significant nontarget heating of muscle tissue in contact with the metal instrumentation.     

Percutaneous CT-Guided Cryoablation of the Celiac Plexus: A Retrospective Cohort Comparison with Ethanol

PurposeTo retrospectively analyze and compare the incidence of diarrhea in patients who underwent cryoablation of the celiac plexus for intractable abdominal pain versus ethanol therapy over a 5-year period.Materials and MethodsFrom June 2014 to August 2019, 83 patients were identified who underwent neurolysis of the celiac plexus for management of intractable abdominal pain by using either cryoablation (n = 39 [59% female; age range, 36–79 years old [average, 60 ± 11 years old]) or alcohol (n = 44 [48% female; age range, 29–76 years old [average, 60 ± 12 years old]). Pain scores and reports of procedure-related complications or side effects, with special attention to diarrhea and/or other gastrointestinal symptoms, were collected from follow-up visits at 1 week, 1 month, and 3 months post-intervention and were compared between groups.ResultsThe mean time of follow-up was 17.7 days. Four patients who underwent cryoablation developed gastrointestinal symptoms consisting of 2 cases of nausea and vomiting and 2 cases of diarrhea (5.1%). Twelve patients who underwent ethanol ablation developed gastrointestinal symptoms, including 1 case of nausea, 3 cases of vomiting, and 9 cases of diarrhea (20.5%). There was a significantly higher incidence of both diarrhea (chi-squared likelihood ratio, P = .03) and overall gastrointestinal symptoms (chi-squared likelihood ratio, P = .04) in the ethanol group than in the cryoablation group.ConclusionsCryoablation of the celiac plexus may provide a new treatment option for intractable abdominal pain, and it appears to have a lower incidence of diarrhea and fewer gastrointestinal side effects than ablation using ethanol.     

Radiofrequency Ablation,Cryoablation, and Microwave Ablation for T1a Renal Cell Carcinoma: A Comparative Evaluation of Therapeutic and Renal Function Outcomes

PurposeTo compare the therapeutic and renal function outcomes of radiofrequency (RF) ablation, cryoablation, and microwave (MW) ablation for treatment of T1a renal cell carcinoma (RCC).Materials and MethodsA retrospective assessment of 297 patients (mean age 72 years range 24–90 years) with biopsy-proven RCC treated with image-guided percutaneous thermal ablation was performed between October 2006 and December 2016. Mean tumor size was 2.4 cm; mean radius, exophytic/endophytic properties, nearness of tumor to collecting system or sinus, anterior/posterior, hilar tumor touching the main renal artery or vein, and location relative to polar lines; Preoperative Aspects and Dimensions Used for an Anatomical; and c-centrality scores were 6.0, 7.0, and 2.8, respectively. Assessments of adverse events, treatment efficacy, and therapeutic outcomes were performed among RF ablation, cryoablation, and MW ablation. The 2-year disease-free, metastatic-free, and cancer-specific survival rates were tabulated. Estimated glomerular filtration rate was used to assess for treatment related changes in renal function.ResultsA total of 297 T1aN0M0 biopsy-proven RCCs measuring 1.2–3.9 cm were treated with computed tomography–guided RF ablation (n = 244, 82%), cryoablation (n = 26, 9%), and MW ablation (n = 27, 9%). There were no significant differences in patient demographics among the 3 groups (P = .09). Technical success rates were similar among the 3 treatments (P = .33). Primary efficacy at 1 month postablation was more likely to be achieved with RF ablation and MW ablation than with cryoablation. At 2 years’ follow-up, there was no local recurrence, metastatic progression, or RCC-related death observed in the 3 groups. There was no significant change in estimated glomerular filtration rate among the 3 ablation groups compared with baseline at 2-year follow-up (P = .71).ConclusionRF ablation, cryoablation, and MW ablation are equivalent at 2 years for treatment of T1a RCC for therapeutic outcome, stability of renal function, and low adverse event rate.     

4D Flow MR Imaging to Improve Microwave Ablation Prediction Models: A Feasibility Study in an In Vivo Porcine Liver

PurposeTo characterize the effect of hepatic vessel flow using 4-dimensional (4D) flow magnetic resonance (MR) imaging and correlate their effect on microwave ablation volumes in an in vivo non-cirrhotic porcine liver model.Materials and MethodsMicrowave ablation antennas were placed under ultrasound guidance in each liver lobe of swine (n = 3 in each animal) for a total of 9 ablations. Pre- and post-ablation 4D flow MR imaging was acquired to quantify flow changes in the hepatic vasculature. Flow measurements, along with encompassed vessel size and vessel-antenna spacing, were then correlated with final ablation volume from segmented MR images.ResultsThe linear regression model demonstrated that the preablation measurement of encompassed hepatic vein size (β = –0.80 ± 0.25, 95% confidence interval [CI] –1.15 to –0.22; P = .02) was significantly correlated to final ablation zone volume. The addition of hepatic vein flow rate found via 4D flow MRI (β = –0.83 ± 0.65, 95% CI –2.50 to 0.84; P = .26), and distance from antenna to hepatic vein (β = 0.26 ± 0.26, 95% CI –0.40 to 0.92; P = .36) improved the model accuracy but not significantly so (multivariate adjusted R² = 0.70 vs univariate (vessel size) adjusted R² = 0.63, P = .24).ConclusionsHepatic vein size in an encompassed ablation zone was found to be significantly correlated with final ablation zone volume. Although the univariate 4D flow MR imaging-acquired measurements alone were not found to be statistically significant, its addition to hepatic vein size improved the accuracy of the ablation volume regression model. Pre-ablation 4D flow MR imaging of the liver may assist in prospectively optimizing thermal ablation treatment.     

Directional Microwave Ablation: Experimental Evaluation of a 2.45-GHz Applicator in Ex Vivo and In Vivo Liver

PurposeTo experimentally characterize a microwave (MW) ablation applicator designed to produce directional ablation zones.Materials and MethodsUsing a 14-gauge, 2.45-GHz side-firing MW ablation applicator, 36 ex vivo bovine liver ablations were performed. Ablations were performed at 60 W, 80 W, and 100 W for 3, 5, and 10 minutes (n = 4 per combination). Ablation zone forward and backward depth and width were measured and directivity was calculated as the ratio of forward to backward depth. Thirteen in vivo ablations were performed in 2 domestic swine with the applicator either inserted into the liver (80 W, 5 min, n = 3; 100 W, 5 min, n = 3; 100 W, 10 min, n = 2) or placed on the surface of the liver with a nontarget tissue placed on the back side of the applicator (80 W, 5 min, n = 5). The animals were immediately euthanized after the procedure; the livers were harvested and sectioned perpendicular to the axis of the applicator. In vivo ablation zones were measured following viability staining and assessed on histopathology.ResultsMean ex vivo ablation forward depth was 8.3–15.5 mm. No backward heating was observed at 60 W, 3–5 minutes; directivity was 4.7–11.0 for the other power and time combinations. In vivo ablation forward depth was 10.3–11.5 mm, and directivity was 11.5–16.1. No visible or microscopic thermal damage to nontarget tissues in direct contact with the back side of the applicator was observed.ConclusionsThe side-firing MW ablation applicator can create directional ablation zones in ex vivo and in vivo tissues.     

Experimental High-Frequency Irreversible Electroporation Using a Single-Needle Delivery Approach for Nonthermal Pancreatic Ablation In Vivo

PurposeTo investigate the feasibility of single-needle high-frequency irreversible electroporation (SN-HFIRE) to create reproducible tissue ablations in an in vivo pancreatic swine model.Materials and MethodsSN-HFIRE was performed in swine pancreas in vivo in the absence of intraoperative paralytics or cardiac synchronization using 3 different voltage waveforms (1-5-1, 2-5-2, and 5-5-5 [on-off-on times (μs)], n = 6/setting) with a total energized time of 100 μs per burst. At necropsy, ablation size/shape was determined. Immunohistochemistry was performed to quantify apoptosis using an anticleaved caspase-3 antibody. A numerical model was developed to determine lethal thresholds for each waveform in pancreas.ResultsMean tissue ablation time was 5.0 ± 0.2 minutes, and no cardiac abnormalities or muscle twitch was detected. Mean ablation area significantly increased with increasing pulse width (41.0 ± 5.1 mm² [range 32–66 mm²] vs 44 ± 2.1 mm² [range 38–56 mm²] vs 85.0 ± 7.0 mm² [range 63–155 mm²]; 1-5-1, 2-5-2, 5-5-5, respectively; p < 0.0002 5-5-5 vs 1-5-1 and 2-5-2). The majority of the ablation zone did not stain positive for cleaved caspase-3 (6.1 ± 2.8% [range 1.8–9.1%], 8.8 ± 1.3% [range 5.5–14.0%], and 11.0 ± 1.4% [range 7.1–14.2%] cleaved caspase-3 positive 1-5-1, 2-5-2, 5-5-5, respectively), with significantly more positive staining at the 5-5-5 pulse setting compared with 1-5-1 (p < 0.03). Numerical modeling determined a lethal threshold of 1114 ± 123 V/cm (1-5-1 waveform), 1039 ± 103 V/cm (2-5-2 waveform), and 693 ± 81 V/cm (5-5-5 waveform).ConclusionsSN-HFIRE induces rapid, predictable ablations in pancreatic tissue in vivo without the need for intraoperative paralytics or cardiac synchronization.     

Adjuvant Thermal Accelerant Gel Use Increases Microwave Ablation Zone Temperature in Porcine Liver as Measured by MR Thermometry

PurposeTo determine the effects of a thermal accelerant gel on temperature parameters during microwave liver ablation.Materials and MethodsSixteen consecutive liver ablations were performed in 5 domestic swine under general anesthesia with (n = 8) and without (n = 8) administration of thermal accelerant gel. Ablation zone temperature was assessed by real-time MR thermometry, measured as maximum temperature (T_max) and the volume of tissue ≥ 60°C (V₆₀). Tissue heating rate, ablation zone shape, and thermal energy deposition using the temperature degree-minutes at 43°C (TDM43) index were also measured. Differences between groups were analyzed using generalized mixed modeling with significance set at P = .05.ResultsMean peak ablation zone temperature was significantly greater with thermal accelerant use (mean T_max, thermal accelerant: 120.0°C, 95% confidence interval [CI] 113.0°C–126.9°C; mean T_max, control: 80.3°C, 95% CI 72.7°C–88.0°C; P < .001), and a significantly larger volume of liver tissue achieved or exceeded 60°C when thermal accelerant was administered (mean V₆₀, thermal accelerant: 22.2 cm³; mean V₆₀, control: 15.9 cm³; P < .001). Significantly greater thermal energy deposition was observed during ablations performed with accelerant (mean TDM43, thermal accelerant: 198.4 min, 95% CI 170.7–230.6 min; mean TDM43, control: 82.8 min, 95% CI 80.5–85.1 min; P < .0001). The rate of tissue heating was significantly greater with thermal accelerant use (thermal accelerant: 5.8 min ± 0.4; control: 10.0 min; P < .001), and accelerant gel ablations demonstrated a more spherical temperature distribution (P = .002).ConclusionsThermal accelerant use is associated with higher microwave ablation zone temperatures, greater thermal energy deposition, and faster and more spherical tissue heating compared with control ablations.     

Robotically-Assisted Sonic Therapy for Renal Ablation in a Live Porcine Model: Initial Preclinical Results

PurposeTo demonstrate the feasibility of Robotically Assisted Sonic Therapy (RAST)—a noninvasive and nonthermal focused ultrasound therapy based on histotripsy—for renal ablation in a live porcine model.Materials and MethodsRAST ablations (n = 11) were performed in 7 female swine: 3 evaluated at 1 week (acute) and 4 evaluated at 4 weeks (chronic). Treatment groups were acute bilateral (3 swine, 6 ablations with immediate computed tomography [CT] and sacrifice); chronic single kidney (3 swine, 3 ablations; CT at day 0, week 1, and week 4 after treatment, followed by sacrifice); and chronic bilateral (1 swine, 2 ablations). Treatments were performed using a prototype system (VortxRx; HistoSonics, Inc) and targeted a 2.5-cm-diameter sphere in the lower pole of each kidney, intentionally including the central collecting system.ResultsMean treatment time was 26.4 minutes. Ablations had a mean diameter of 2.4 ± 0.3 cm, volume of 8.5 ± 2.4 cm³_, and sphericity index of 1.00. Median ablation volume decreased by 96.1% over 4 weeks. Histology demonstrated complete lysis with residual blood products inside the ablation zone. Temporary collecting system obstruction by thrombus was observed in 4/11 kidneys (2 acute and 2 chronic) and resolved by 1 week. There were no urinary leaks, main vessel thromboses, or adjacent organ injuries on imaging or necropsy.ConclusionsIn this normal porcine model, renal RAST demonstrated complete histologic destruction of the target renal tissue while sparing the urothelium.     

High-Frequency Irreversible Electroporation for Treatment of Primary Liver Cancer: A Proof-of-Principle Study in Canine Hepatocellular Carcinoma

PurposeTo determine the safety and feasibility of percutaneous high-frequency irreversible electroporation (HFIRE) for primary liver cancer and evaluate the HFIRE-induced local immune response.Materials and MethodsHFIRE therapy was delivered percutaneously in 3 canine patients with resectable hepatocellular carcinoma (HCC) in the absence of intraoperative paralytic agents or cardiac synchronization. Pre- and post-HFIRE biopsy samples were processed with histopathology and immunohistochemistry for CD3, CD4, CD8, and CD79a. Blood was collected on days 0, 2, and 4 for complete blood count and chemistry. Numeric models were developed to determine the treatment-specific lethal thresholds for malignant canine liver tissue and healthy porcine liver tissue.ResultsHFIRE resulted in predictable ablation volumes as assessed by posttreatment CT. No detectable cardiac interference and minimal muscle contraction occurred during HFIRE. No clinically significant adverse events occurred secondary to HFIRE. Microscopically, a well-defined ablation zone surrounded by a reactive zone was evident in the majority of samples. This zone was composed primarily of maturing collagen interspersed with CD3⁺/CD4⁻/CD8⁻ lymphocytes in a proinflammatory microenvironment. The average ablation volumes for the canine HCC patients and the healthy porcine tissue were 3.89 cm³ ± 0.74 and 1.56 cm³ ± 0.16, respectively (P = .03), and the respective average lethal thresholds were 710 V/cm ± 28.2 and 957 V/cm ± 24.4 V/cm (P = .0004).ConclusionsHFIRE can safely and effectively be delivered percutaneously, results in a predictable ablation volume, and is associated with lymphocytic tumor infiltration. This is the first step toward the use of HFIRE for treatment of unresectable liver tumors.     

Partial Splenic Artery Embolization in 35 Cancer Patients: Results of a Single Institution Retrospective Study

PurposeTo evaluate the safety and efficacy of partial splenic embolization (PSE) in cancer patients with different etiologies of splenomegaly/hypersplenism.Materials and MethodsThe medical records of 35 cancer patients who underwent 39 PSE procedures were analyzed. The splenomegaly/hypersplenism was due to chemotherapy (n = 17), portal hypertension (n = 10), or hematologic malignancy (n = 8). After the first 11 PSEs, celiac plexus neurolysis, corticosteroids, and non-steroid anti-inflammatory drugs (NSAIDs) were included in the post-procedural management.ResultsPSE led to 59 ± 16% (mean ± standard deviation) splenic infarcts. The infarct volume per 1 mL 300–500 μm tris-acryl gelatin microspheres was not significantly different between the chemotherapy-induced group (264 ± 89 cm³) and the portal hypertension group (285 ± 139 cm³) but was significantly higher in the hematology group (582 ± 345 cm³). Platelet count increased from 65.7 ± 19.7 k/μl to a peak platelet count of 221 ± 83 k/μl at 2 weeks after PSE. Patients with a follow-up period of more than 1 year had the most recent platelet count of 174 ± 113 k/μl. Platelet count increase was significantly higher in the chemotherapy-induced group than the portal hypertension group. Adding celiac plexus neurolysis, corticosteroids, and NSAIDs to the post-procedural management resulted in a decreased rate of major complications from 73% to 46% and a decrease in the rate of moderate or severe pain from 92% to 20%.ConclusionsPSE improved platelet counts in cancer patients despite different etiologies of splenomegaly. The addition of celiac plexus neurolysis, corticosteroids, and NSAIDS to the post-PSE treatment protocol reduced complications. Data from this study could help to predict the amount of 300–500 μm tris-acryl gelatin microspheres required to achieve a planned infarct size.     

Percutaneous Cryoablation: Safety and Efficacy for Pain Palliation of Metastases to Pleura and Chest Wall

PurposeTo assess safety and efficacy of percutaneous cryoablation for pain palliation of metastases to pleura and chest wall.Materials and MethodsThis retrospective single-center cohort study included 22 patients (27% female, mean age 63 y ± 11.4) who underwent 25 cryoablation procedures for pain palliation of 39 symptomatic metastases measuring 5.1 cm ± 1.9 (range, 2.0–8.0 cm) in pleura and chest wall between June 2012 and December 2017. Pain intensity was assessed using a numerical scale (0–10 points). Statistical tests t test, χ², and Wilcoxon signed rank were performed.ResultsPatients were followed for a median of 4.1 months (interquartile range [IQR], 2.3–10.1; range, 0.1–36.7 mo) before death or loss to follow-up. Following cryoablation, pain intensity decreased significantly by a median of 4.5 points (IQR, 2.8–6; range, 0–10 points; P = .0002 points, Wilcoxon signed rank). Pain relief of at least 3 points was documented following 18 of 20 procedures. Pain relief occurred within a median of 1 day following cryoablation (IQR, 1–2; range, 1–4 d) and lasted for a median of 5 weeks (IQR, 3–17; range, 1–34 wk). Systemic opioid requirements decreased in 11 of 22 patients (50%) by an average of 56% ± 34. Difference in morphine milligram equivalents was not significant (P = .73, Wilcoxon signed rank). No procedure-related complications occurred despite previous radiation of 7 tumors. Of 25 procedures, 22 (88%) were performed on an outpatient basis.ConclusionsPercutaneous cryoablation for metastases to pleura and chest wall can safely provide significant pain relief within days following a single session.     

Thermal Ablation,Embolization, and Selective Internal Radiation Therapy Combined with Checkpoint Inhibitor Cancer Immunotherapy: Safety Analysis

PurposeTo describe interventional oncology therapies combined with immune checkpoint inhibitor (ICI) therapy targeting the programmed death 1 pathway in patients with different neoplasms.Materials and MethodsThis was a retrospective cohort study of patients who underwent tumor-directed thermal ablation, embolization, or selective internal radiation therapy (SIRT) between January 1, 2011, and May 1, 2019, and received anti–programmed death 1/PD-L1 agents ≤ 90 days before or ≤ 30 days after the interventional procedure. Immune-related adverse events (irAEs) and procedural complications ≤ 90 days after the procedure were graded according to the Common Terminology Criteria for Adverse Events version 5.0. The study included 65 eligible patients (49% female; age 63 years ± 11.1). The most common tumors were metastatic melanoma (n = 28) and non–small cell lung cancer (NSCLC) (n = 12). Patients underwent 78 procedures (12 patients underwent > 1 procedure), most frequently SIRT (35.9%) and cryoablation (28.2%). The most common target organs were liver (46.2%), bone (24.4%), and lung (9.0%). Most patients received ICI monotherapy with pembrolizumab (n = 30), nivolumab (n = 22), and atezolizumab (n = 6); 7 patients received ipilimumab and nivolumab.ResultsSeven (10.8%) patients experienced an irAE (71.4% grade 1–2), mostly affecting the skin. Median time to irAE was 33 days (interquartile range, 19–38 days). Five irAEs occurred in patients with melanoma, and no irAEs occurred in patients with NSCLC. Management required corticosteroids (n = 3) and immunotherapy discontinuation (n = 1); all irAEs resolved to grade ≤ 1. There were 4 intraprocedural and 32 postprocedural complications (77.8% grade < 3). No grade 5 irAEs and/or procedural complications occurred.ConclusionsNo unmanageable or unanticipated toxicities occurred within 90 days after interventional oncology therapies combined with ICIs.     

Image-Guided Ablation of Recurrent or Unresectable Intrahepatic Cholangiocarcinoma

PurposeTo assess the safety and effectiveness of image-guided ablation of recurrent or unresectable intrahepatic cholangiocarcinoma (ICC).Materials and MethodsIn this retrospective study, 25 patients (14 women; age, 36–84 years) underwent 37 image-guided liver tumor ablation procedures to treat 47 ICCs (May 2004 to January 2022). At initial diagnosis, 20 patients had Stage 1 or 2 disease and 5 had Stage 3 or 4 disease. Before ablation, 19 (76.0%) of the 25 patients had progressed through prior treatments, including resection (n = 11), chemotherapy (n = 11), transarterial embolization (n = 3), or radiotherapy (n = 1); 6 (24.0%) of the 25 patients were treatment naïve. Ablation modality selection was based on patient and tumor characteristics and operator preference. Primary outcomes included local progression–free survival (LPFS) and overall survival (OS) after ablation. Statistical analysis included Kaplan-Meier (KM) survival analyses and Cox proportional hazards models.ResultsThe mean ablated tumor size was 2.0 cm ± 1.2 (range, 0.5–5.0 cm). The 1-, 2-, and 5-year LPFS rates were 84.0% (95% CI, 72.9–96.8), 73.0% (95% CI, 59.0–90.4), and 59.5% (95% CI, 41.6–85.1), respectively. The 1-, 2-, and 5-year secondary LPFS rates were 89.5% (95% CI, 80.2–99.9), 81.9% (95% CI, 69.4–96.6), and 75.6% (95% CI, 60.2–94.9). The 1-, 2-, and 5-year LPFS rates for tumors ≤2 cm in size were all 95.8% (95% CI, 88.2–100.0). The 1-, 2-, and 5-year OS rates were 78.5% (95% CI, 63.5–97.2), 68.4% (95% CI, 51.3–91.1), and 43.5% (95% CI, 23.5–80.5). Larger tumor size was associated with decreased time to local progression (hazard ratio, 1.93; P = .012).ConclusionsPercutaneous ablation provided favorable intermediate to long-term disease control for patients with recurrent or inoperable cholangiocarcinoma.     

Percutaneous MR Imaging–Guided Laser Ablation for the Treatment of Symptomatic Cervicofacial Vascular Malformations

PurposeTo evaluate the safety and effectiveness of percutaneous magnetic resonance (MR) imaging–guided laser ablation for the treatment of symptomatic soft tissue vascular malformations (VMs) in the face and neck.Materials and MethodsAn institutional review board–approved retrospective review was undertaken of all consecutive patients who underwent MR imaging–guided and monitored laser ablation for treatment of symptomatic, cervicofacial soft tissue VM. Preablation and postablation MR imaging findings were independently reviewed. Preablation and postablation VM sizes were documented. Preablation T2 signal characteristics and enhancement patterns as well as postablation change in both signal and enhancement were semiquantitatively assessed. Changes in VM size were compared using a paired t test.ResultsThirteen patients (women, 9; age, 14.5–69.5 years) with 13 VMs were treated for moderate-to-severe pain (n = 4), swelling/mass effect (n = 8), or predominantly cosmesis (n = 1) with 22 total ablation sessions. The baseline maximum VM diameter was 5.7 cm ± 4.2. At baseline, all VMs (100%) demonstrated variable T2-weighted signal hyperintensity and enhancement. For painful VM, the baseline pain score was 8 ± 1. Clinical follow-up was available for 10 patients. Of patients with available follow-up, 3 (100%) treated for moderate-to-severe pain and 7 (100%) treated for swelling/mass effect reported subjective complete or partial symptomatic relief. The patient treated predominantly for cosmetic reasons was lost to follow-up. Two patients (15.4%) experienced minor adverse events by the Society of Interventional Radiology standards. There were no major adverse events.ConclusionsMR imaging–guided and monitored percutaneous laser ablation is safe and effective for the treatment of symptomatic, cervicofacial VMs.     

Gallbladder Cryoablation for Chronic Cholecystitis in High-Risk Surgical Patients: 1-Year Clinical Experience with Imaging Follow-up

PurposeTo assess the short-term safety and efficacy of gallbladder cryoablation in high-risk patients.Materials and MethodsA single-center, retrospective review of clinical and imaging follow-up from patients who were referred for gallbladder cryoablation between August 2018 and July 2019 was performed. All patients had serious pre-procedural comorbidities and were unacceptable surgical candidates (mean age, 52.5 years; mean American Society of Anesthesiologists score, 3.67). Primary efficacy measures included technical success, absence of symptoms after cholecystostomy tube removal, and imaging evidence of cystic duct obstruction and gallbladder involution. The primary safety measure was the absence of Society of Interventional Radiology moderate or greater adverse events.ResultsTechnical success was 86%, with 1 of 7 patients unable to undergo cryoablation because of adhesions preventing hydrodissection of the colon away from the gallbladder. Mean duration of clinical follow-up after discharge was 278 days (range, 59–498 days). Abdominal pain was absent in all patients after ablation. Cholecystostomy tubes were removed immediately after ablation (n = 5) or on post-procedure day 11 (n = 1). Computed tomography or magnetic resonance imaging was obtained at 1–3 months (n = 6), 4–6 months (n = 4), and 6–12 months (n = 5) after the procedure and demonstrated gallbladder involution in 5 of 6 patients. One patient had asymptomatic distention of the gallbladder on follow-up imaging. Hepatobiliary iminodiacetic acid scans were completed in 5 of 6 patients 1 month after ablation and demonstrated cystic duct occlusion in all 5 patients. One moderate adverse event (infection) and 1 life-threatening adverse event (hemorrhage) occurred.ConclusionsGallbladder cryoablation might be a viable treatment option for high-risk patients with gallbladder disease and warrants further investigation.     

MR Imaging‒Guided Intervention: Evaluation of MR Conditional Biopsy and Ablation Needle Tip Artifacts at 3T Using a Balanced Fast Field Echo Sequence

PurposeTo systematically investigate artifacts produced by biopsy and ablation needles imaged at various trajectories with respect to the static magnetic field (B0).Materials and MethodsAn acrylic phantom was scanned using a rapid balanced fast field echo sequence with 3.0-T magnetic resonance imaging. A 15-gauge microwave needle, a 17-gauge cryoneedle, and an 18-gauge coaxial biopsy needle were imaged in sagittal and axial planes, in 7 different orientations to B0 (0°, 15°, 30°, 45°, 60°, 75°, and 90°). For 4 angles (15°, 30°, 60°, and 75°), images were acquired with the slice orientation aligned to the needle angulation, resulting in the frequency encoding direction being parallel to the needle’s long axis for the sagittal slice and perpendicular to the needle angulation for the axial acquisition. The artifact length at the needle tip and maximum artifact width were recorded.ResultsNo significant difference was noted in mean artifact length for the cryoneedle (13 mm; 95% confidence interval [CI], 7–19) and coaxial biopsy needle (8 mm; 95% CI, 5–10; P = .08). The mean artifact length was significantly smaller for the microwave ablation needle (1 mm; 95% CI, 0–2; P < .05). The mean artifact width was highest for the coaxial needle (17 mm; 95% CI, 14–19) and significantly higher than the cryoneedle (12 mm; 95% CI, 10–15; P = .024) and microwave ablation needle (8 mm; 95% CI, 6–10; P < .01). The needle tip artifact was significantly smaller when the slice orientation was aligned to the needle angulation for the coaxial and cryoablation needles (P < .01).ConclusionsNeedle tip artifact length and width increase with increasing angulation to the static field. At large angles (>15°), the needle tip position can be predicted better from images acquired when the slice orientation is aligned to the needle’s angulation.