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Purpose To determine safety and efficacy of retrograde pyeloperfusion for ureteral protection during cryoablation of adjacent renal tumors. Materials and Methods Retrospective 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. Results Technical 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. Conclusions Retrograde 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.

Purpose To evaluate the use of dual-energy computed tomography (CT) virtual noncalcium imaging (VNCa) to visualize ice ball growth during skeletal cryoablation procedures in the spine and bony pelvis. Materials and Methods Cryoablation was performed in the spine and bony pelvis of swine and human cadavers at 5 and 6 locations, respectively. CT scans were acquired every 2 minutes using a dual-source dual-energy scanner. Artifacts were suppressed using iterative metal artifact reduction, and ablation zones in the bones and surrounding tissue were visualized using multiplanar VNCa and mixed kV imaging. For each probe location and time point, ice detectability was determined and the volume of the ice was measured. Results At each location, ice was visualized within the bone before reaching critical neural and intraabdominal structures. Within bone, the ice ball could not be visualized on mixed kV images, but was seen using VNCa images before reaching the adjacent soft tissue in 7/11 (64%) scenarios. Volume of the smallest ice ball seen in VNCa images was 18% of the final volume after cryoablation compared with 42% for mixed kV (P = .014). Conclusions This application of dual-energy CT and VNCa imaging to cryoablation monitoring permits earlier ice visualization within the vertebral column and pelvic bones in near real time. Because these scanners and imaging techniques increase in availability in interventional suites, cryoablation of tumors along the spine and pelvic bone potentially could be performed with greater confidence.

Purpose To retrospectively evaluate effectiveness and safety of percutaneous CT-guided rib biopsy. Materials and Methods CT-guided core rib biopsies were performed in 249 consecutive patients between January 2002 and June 2016. Mean patient age was 64.8 years ± 13.8. Additional patient demographics, rib lesion characteristics, and procedural techniques were reviewed. Diagnostic yield was assessed, and complications were classified using SIR criteria. Results Mean maximal diameter of 249 rib lesions was 2.7 cm ± 1.8, and 107 (43%) rib lesions had an associated extraosseous soft tissue component. Of rib lesions, 172 (69%) were lytic, 75 (30%) were sclerotic, and 2 (1%) were identifiable only with positron emission tomography/CT correlation. Specimens from 241 (96.8%) biopsies were adequate for pathologic diagnosis, whereas 8 (3.2%) were nondiagnostic. Of diagnostic biopsies, 168 (69.7%) were positive for malignancy; 73 (30.3%) revealed benign etiologies. There was a significant difference in diagnostic biopsy rate depending on size of the rib lesion (mean 2.8 cm ± 1.8 for diagnostic biopsies vs mean 1.3 cm ± 0.5 for nondiagnostic biopsies; P = .007). Of rib lesions, 170 (99%) lytic lesions and 69 (92%) sclerotic lesions yielded diagnostic biopsies; diagnostic biopsy rate was significantly higher for lytic lesions than sclerotic lesions (P = .01). There were 14 (5.6%) minor complications and no major complications. Conclusions Percutaneous CT-guided core rib biopsy resulted in high diagnostic yield and low complications. Diagnostic biopsy rates were higher with larger lesion size and lytic rib lesions.

Purpose To determine if the use of heat-based track ablation with new-generation cryoprobes is associated with decreased renal cryoablation bleeding complications. Materials and Methods Eighty-nine patients who underwent percutaneous cryoablation for treatment of a solitary renal mass with the use of cryoprobes with track ablation (CwTA) from October 29, 2015, to May 18, 2017, were compared with a propensity score–matched control group of 178 patients who underwent treatment with the use of cryoprobes without track ablation (Cw/oTA) from January 5, 2012, to October 28, 2015. Bleeding complications were assessed with the use of the Clavien-Dindo classification system and compared between the matched patient groups by means of conditional logistic regression, both univariately and in a multivariate model to adjust for imbalanced covariates. Change in patient hemoglobin was evaluated as a secondary measure of periprocedural bleeding. Results Seven of the 89 patients (7.9%) who underwent percutaneous renal cryoablation with the use of CwTA developed major (grade ≥3) bleeding complications, versus 13 of the 178 patients (7.3%) treated with the use of Cw/oTA. Conditional logistic regression analysis adjusted for potential confounders showed that major, minor, and overall bleeding complications were not associated with the type of cryoprobes used for treatment ( P values .727, .370, and .733, respectively). There was also no significant difference in postprocedural change in hemoglobin for patients treated with the use of CwTA compared with Cw/oTA ( P = .909). Furthermore, total duration of track ablation in patients with bleeding complications (mean 169 seconds, SD 68, range 60–240) was not significantly different than in patients without bleeding complications (mean 171 seconds, SD 86, range 30–360; P = .940). Conclusions The use of cryoprobes with heat-based track ablation did not decrease the incidence of bleeding complications after renal cryoablation compared with procedures performed without track ablation.

Purpose To assess feasibility, safety, and oncologic outcomes of cryoablation in treatment of renal cell carcinoma (RCC) with extension into adjacent renal sinus vein. Materials and Methods Review of an internally maintained renal ablation registry identified 7 patients (4 men and 3 women; median age 62 y; age range, 45–91 y) who underwent percutaneous cryoablation of RCC with imaging consistent with extension of tumor into an immediately adjacent renal sinus vein. Four of 7 (57%) patients had recurrent tumors following prior partial nephrectomy. Three of 7 patients (43%) had solitary kidneys. Results Median tumor size was 4.3 cm (range, 1.9–5.0 cm). Biopsy showed RCC in 6 of 7 patients. Technical success was achieved in 6 of 7 tumors (86%) There was a single Clavien grade 3 major complication. Median hospital stay was 1 night (range, 1–3 nights). Follow-up imaging performed in the 6 successfully treated patients at median 11 months (range, 2–101 months) showed no local tumor progression. In 2 patients with solitary kidneys, estimated glomerular filtration rate declined from 63 mL/min/1.73 m 2 to 45 mL/min/1.73 m 2 and 67 mL/min/1.73 m 2 to 40 mL/min/1.73 m 2 at 101 months and 12 months following treatment, respectively. Estimated glomerular filtration rate remained > 60 mL/min/1.73 m 2 in the remaining patients. Conclusions In this small select group of patients, percutaneous cryoablation afforded a safe and, based on early outcomes, effective means of providing local control of locally invasive RCC. Percutaneous cryoablation may obviate the need for nephrectomy in similar patients.

Musculoskeletal interventions are increasingly used with palliative and curative intent in the multidisciplinary treatment of oncology patients with bone and soft-tissue tumors. There is an unmet need for high-quality evidence to guide broader application and adoption of minimally invasive interventional technologies to treat these patients. Therefore, the Society of Interventional Radiology Foundation and the Society of Interventional Oncology collaborated to convene a research consensus panel to prioritize a research agenda addressing the gaps in the current evidence. This article summarizes the panel’s proceedings and recommendations for future basic science and clinical investigation to chart the course for interventional oncology within the musculoskeletal system. Key questions that emerged addressed the effectiveness of ablation within specific patient populations, the effect of combination of ablation with radiotherapy and/or immunotherapy, and the potential of standardization of techniques, including modeling and monitoring, to improve the consistency and predictability of treatment outcomes.

Purpose To evaluate success and complication rates of percutaneous ultrasound-guided thrombin injection of nongroin pseudoaneurysms (PSAs). Materials and Methods Retrospective review of a prospectively maintained institutional database yielded 39 cases of arterial PSAs occurring at nongroin sites that were treated with percutaneous ultrasound-guided thrombin injection between 2000 and 2016 (average patient age 69.2 y ± 14.0). Of PSAs, 74.4% (29/39) arose in the upper extremities, and 92.3% (36/39) were iatrogenic. The brachial artery was the most commonly affected vessel (51.3% [20/39]), and arterial access was the most common cause (56.4% [22/39]). Average overall PSA size was 2.4 cm (range, 0.5–7.2 cm); average amount of thrombin injected was 320 IU (range, 50–2,000 IU). Technical success was defined as absence of flow within the PSA immediately after thrombin injection. Treatment success was defined as sustained thrombosis on follow-up imaging obtained at 1–3 days after treatment. Results Technical and treatment success rates of thrombin injections were 100% (39/39) and 84.8% (28/33), respectively. Longer term follow-up imaging (average 71 d; range, 12–201 d) was available for 7 of the treatment successes with 100% (7/7) showing sustained thrombosis. Comparing treatment successes and failures, there was no significant difference in average PSA size (2.3 cm vs 2.0 cm, P = .51) or average amount of thrombin injected (360 IU vs 180 IU, P = .14). There were no complications. Conclusions Ultrasound-guided thrombin injection is a safe, efficacious treatment option for PSAs arising in nongroin locations.

Purpose To perform a national analysis of the safety and cost of percutaneous image-guided lung malignancy ablation. Materials and Methods Using the National (Nationwide) Inpatient Sample, we evaluated complications, need for further intervention, in-hospital mortality, length of hospitalization, and hospital charges for patients undergoing inpatient percutaneous image-guided lung ablation in the United States during the period 2007–2011. Additionally, an analysis of the relationship between specific patient factors, procedural complications, and mortality was performed. Results The study group consisted of 3,344 patients, including 2,072 (61.9%) patients treated for primary lung carcinomas and 1,277 (38.1%) patients treated for pulmonary metastatic disease. In-hospital mortality occurred after 43 (1.3%) ablation procedures. A Charlson comorbidity index score ≥ 4 was associated with higher mortality (odds ratio [OR], 2.84; 95% confidence interval [CI], 1.16–6.91). Pneumothorax was the most common complication (38.4%), followed by pneumonia (5.7%) and effusion (4.0%). Neither pneumothorax nor chest tube insertion was associated with higher in-hospital mortality rates (pneumothorax, OR, 1.10; 95% CI, 0.59–2.04, and chest tube insertion, OR, 1.45; 95% CI, 0.78–2.68). Surgical reintervention via thoracoscopy or thoracotomy occurred in 31 cases (0.9%). Median length of hospitalization was 1 day (interquartile range, 1–3 d), and median hospital charges were $22,320 (interquartile range, $13,705–$43,026). Conclusions Percutaneous image-guided lung ablation of primary and metastatic disease has an acceptable safety profile, and surgical reintervention is rarely required. The most frequent complications of percutaneous lung ablation were not associated with increased in-hospital mortality.

Purpose To determine safety and effectiveness of cryoablation of sternal metastases for pain palliation and local tumor control. Materials and Methods A tumor ablation database was retrospectively reviewed for sternal cryoablation procedures performed between January 2005 and June 2013, which yielded 15 procedures to treat 12 sternal metastases in 12 patients (five men). Median patient age was 57 years (range, 38–80 y). Metastases arose from five primary sites (breast, lung, kidney, ampulla, and thyroid), and median tumor size was 3.8 cm (range, 2.2–7.5 cm). Seven patients (58%) underwent cryoablation for pain palliation, and five (42%) underwent cryoablation for local tumor control of oligometastatic disease. Clinical outcomes (including complications, local tumor control, and pain response) were evaluated retrospectively. Results Mean pain scores decreased from 7.0 ± 1.9 (median, 7; range, 4–10) at baseline to 1.8 ± 1.2 (median, 1.5; range, 0–4) following cryoablation ( P = .00049). Two patients had durable pain palliation, and four had greater than 1 month of pain relief, with a median duration of 5.7 months (range, 1.5–14.7 mo). Two patients in whom recurrent pain developed underwent repeat cryoablation, with durable pain relief. Allowing for a single repeat treatment, local tumor control was achieved in four of five patients (80%) treated for this indication, with median follow-up of 8.4 months (range, 2.6–13.6 mo). In one patient (8%), an infectious complication developed that was successfully treated with antibiotics on an outpatient basis. Conclusions Cryoablation is a safe and potentially effective treatment for patients with painful sternal metastases and can achieve local tumor control in select patients.

Purpose To describe the use of intraprocedural motor evoked potential (MEP) monitoring to minimize risk of neural injury during percutaneous cryoablation of perineural musculoskeletal tumors. Materials and Methods A single-institution retrospective review of cryoablation procedures performed to treat perineural musculoskeletal tumors with the use of MEP monitoring between May 2011 and March 2013 yielded 59 procedures to treat 64 tumors in 52 patients (26 male). Median age was 61 years (range, 4–82 y). Tumors were located in the spine (n = 27), sacrum (n = 3), retroperitoneum (n = 4), pelvis (n = 22), and extremities (n = 8), and 21 different tumor histologies were represented. Median tumor size was 4.0 cm (range, 0.8–15.0 cm). Total intravenous general anesthesia, computed tomographic guidance, and transcranial MEP monitoring were employed. Patient demographics, tumor characteristics, MEP findings, and clinical outcomes were assessed. Results Nineteen of 59 procedures (32%) resulted in decreases in intraprocedural MEPs, including 15 (25%) with transient decreases and four (7%) with persistent decreases. Two of the four patients with persistent MEP decreases (50%) had motor deficits following ablation. No functional motor deficit developed in a patient with transient MEP decreases or no MEP change. The risk of major motor injury with persistent MEP changes was significantly increased versus transient or no MEP change ( P = .0045; relative risk, 69.8; 95% confidence interval, 5.9 to > 100). MEP decreases were 100% sensitive and 70% specific for the detection of motor deficits. Conclusions Persistent MEP decreases correlate with postprocedural sustained motor deficits. Intraprocedural MEP monitoring helps predict neural injury and may improve patient safety during cryoablation of perineural musculoskeletal tumors.

Image-guided percutaneous ablation of bone metastases is an effective, minimally invasive alternative to conventional therapies in the palliation of pain from metastatic disease. Ablative technologies applied in the treatment of skeletal metastases include radiofrequency ablation, cryoablation, microwave ablation, laser ablation, ethanol ablation, and, most recently, focused ultrasound. These ablative methods may be performed in combination with percutaneous cementoplasty to provide support and stabilization for metastases in weight-bearing bones at risk for pathologic fracture.

Purpose: This study measured the F-18 FDG and C-11 Choline activity on PET/CT scans before and after percutaneous ablation of bone tumors comparing these values to local tumor recurrence and pain/functional status in the ablated region. Materials: Using our institutional tumor ablation database, patients with PET/CT scans acquired before and after bone tumor ablation procedures performed between January 1, 2002 and September 1, 2015 were identified. F-18 FDG and C-11 Choline PET/CTs were evaluated for preand post-ablation maximum SUV with readers blinded to clinical information except for the location of the targeted bone metastasis. For SUV determination, a region of interest (ROI) incorporating the lesion was manually placed by the radiologist. The SUVmax was subtracted from blood pool (right atria), and a ratio comparing SUVmax before and after ablation (SUVmax post-ablation/SUVmax pre-ablation) was calculated. Clinical information, including patient demographics, pain level and function, and oncologic outcome, was obtained from the electronic medical record. Local tumor recurrence was defined as any growth on CT, MRI, or by tissue sample. Results: This study identified 96 patients with a mean age of 58.3 years (SD 15.4 years, range 26-83) at time of bone ablation with a PET positive bone lesion prior to ablation and at least one PET/CT post ablation. Eight-one of the patients were followed with F-18 FDG PET and 15 with C-11 Choline PET. Patients with no evidence of local tumor recurrence and overall better functionality/decreased pain had a lower SUVmax ratio, mean 0.37±0.0.780, relative to patients who had evidence of local recurrence and worsening pain, mean 2.04± 1.68 (p o0.04). There was no correlation between SUV and interval between ablation procedure and post-ablation PET/CT (mean 516.5 days, range 15-2081) with an R value of 0.0179. Conclusions: Patients with no evidence of locally recurrent disease and decreased pain had significantly lower SUVmax ratios than with evidence of recurrence independent of duration of follow up. This suggests that any increase in PET radiotracer uptake within the ablation bed is concerning for recurrence regardless of the imaging time interval post ablation.