Safety and Efficacy of Percutaneous Morton Neuroma Cryoneurolysis Under Ultrasound Guidance.

PURPOSE: To assess the technical success, safety and early efficacy of Morton neuroma (MN) cryoneurolysis. MATERIALS AND METHODS: Retrospective review of 54 consecutive patients with MN treated with cryoneurolysis after failure of conservative treatment, from September 2022 to June 2023. Outcomes measurements included technical success (defined a successful ultrasound-guided placement of the cryoprobe), procedural safety according to Cirse classification and change in 6 months post-procedure by pain numeric rating scale (pNRS). RESULTS: A total of 59 MN were treated during 55 procedures. Mean procedure duration was 47 min, all patients were discharged 2 h after the intervention. Technical success was 98.1%. No Cirse grade 3, 4 or 5 complication was reported. Three grade 2 complication occurred, including two chilblain-type lesions and one bone insufficiency fracture. At 6 months post-procedure, pNRS score was significantly decreased (2.7 ± 2.2 vs 7.1 ± 1.1) (p < 0.0001), with a mean score decrease of 4.1points. Thirty-two patients (60.4%) reported a complete pain relief, 15 (28.3%) a partial pain relief and 6 (11.3%) no pain relief, or increased pain. CONCLUSION: Cryoneurolysis seems to be safe for the treatment of Morton neuroma. Six-month pain relief is promising and needs to be confirmed at long term.

Thermal ablation of ultrasound and non-contrast computed tomography invisible primary and secondary liver tumors: targeting by selective intra-arterial lipiodol injection.

PURPOSE: To evaluate the technical feasibility and outcomes of thermal ablation following selective intra-arterial lipiodol injection (SIALI) for targeting primary and secondary liver tumors invisible on ultrasound (US) and non-contrast computed tomography (CT). METHODS: This retrospective study included 18 patients with 20 tumors (67% male, mean age 60.8 ± 12.1 years). The 20 tumors included 15 liver metastases and 5 hepatocellular carcinomas. All patients underwent single-session SIALI and subsequent CT-guided thermal ablation. The primary outcome was a technical success, defined as visualization of the tumor after SIALI and successful thermal ablation. Secondary outcomes were local recurrence rate and procedure-related complications. RESULTS: The median tumor size was 1.5 (1-2.5) cm. In addition, SIALI was performed with a median volume of 3 (1-10) mL of lipiodol resulting in intra-tumoral iodized oil accumulation in 19 tumors and negative imprint with iodized oil accumulation of the surrounding liver parenchyma in 1 tumor. The technical success rate was 100%. No local occurrence was observed at a mean follow-up time of 3 ± 2.5 years. CONCLUSION: SIALI to tag liver tumors not visible with US and non-contrast CT before percutaneous ablation is highly feasible and has a high success rate for the treatment of both primary and secondary liver tumors.

Coil Embolization of Variant Hepatic Arteries During Percutaneous Arterial Port Catheter Placement for Intraarterial Chemotherapy: Analysis of Intrahepatic Perfusion Redistribution and Treatment Efficacy.

PURPOSE: The purpose of this study was to analyze the intrahepatic perfusion redistribution after embolization of hepatic arterial variants during percutaneous arterial port catheter placement as well as to investigate the treatment efficacy of intraarterial chemotherapy in perfusion redistribution-dependent compared to redistribution-independent liver areas. MATERIALS AND METHODS: This retrospective study included 62 patients (67.7% males, mean age of 56 ± 12 years). A replaced left hepatic artery was encountered in 36/62 (58.1%), a replaced right hepatic artery in 19/62 (30.6%) and a replaced left and right hepatic artery in 7/62 of patients (11.3%), respectively. Subjective perfusion analysis was performed on digital subtracted angiography and computed tomography (CT)/cone-beam computed tomography (CBCT) images evaluating the visibility of the main, segmental and subsegmental branches of the embolized variant hepatic artery, re-perfused from intrahepatic arterial anastomoses. For objective perfusion analysis ROI measurements on CT/CBCT images were taken in the redistribution-dependent and redistribution-independent liver lobe. Response analysis according to RECIST 1.1 was separately calculated for the redistribution-dependent and redistribution-independent liver lobe. RESULTS: Intrahepatic reperfusion of the embolized variant hepatic artery was observed immediately after embolization with visualization of the subsegmental branches in 95.2% of patients. ROI measurements on CT/CBCT images (right lobe mean 76 ± 30.2 HU, left lobe mean 74.4 ± 30.5, p-value 0.88) did not show any differences. Treatment response after intraarterial chemotherapy did not differ between the redistribution-dependent and redistribution-independent liver lobes. CONCLUSION: Embolization of hepatic arterial variants during percutaneous arterial port catheter placement results in effective intrahepatic perfusion redistribution and does not compromise treatment efficacy of intraarterial chemotherapy in the redistribution-dependent liver lobe.

Single-session transarterial chemoembolization combined with percutaneous thermal ablation in liver metastases 3 cm or larger.

PURPOSE: The purpose of this study was to evaluate the safety and efficacy of transarterial chemoembolization (TACE) combined with percutaneous thermal ablation in patients with liver metastases 3 cm in diameter or larger. MATERIALS AND METHODS: This retrospective study included 39 patients with a total of 46 liver metastases treated. There were 14 men and 25 women, with a mean age of 55 ± 13.3 (SD) (age range: 28-77 years). All patients were treated with a combination of TACE and thermal ablation in a single session. Primary outcome was local tumor progression. Secondary outcomes were procedure related complications and systemic disease progression. RESULTS: Mean tumor size was 3.6 ± 0.6 (SD) cm (range: 3-5 cm). Conventional TACE was performed in 32 liver metastases (32/46; 70%) and drug-eluting beads-TACE in 14 liver metastases (14/46; 30%) followed by radiofrequency ablation in 34 (34/46; 74%), microwave ablation in 11 (11/46; 24%) and cryoablation in one (1/46; 2%) metastasis. Four grade 2 (4/39; 10%) complications were observed. After a mean follow up of 31.9 ± 26.1 (SD) months (range: 2-113 months) overall local tumor progression rate was 15% (7/46). Local tumor progression rate at 12 months was 13% (6/46). Overall systemic disease progression was seen in 29 patients (29/39; 74%) with a systemic disease progression rate at 12 months of 59% (23/39). CONCLUSION: Treatment of large liver metastases with TACE and thermal ablation in a single session is safe and achieves high local control rate.

Percutaneous Fixation of Impending Fracture of the Hip.

According to the literature, prophylactic consolidation of proximal femur lytic metastasis the is recommended when the Mirels' score is above 8. Osteoplasty (cementoplasty of proximal femur) alone provides inadequate consolidation. Various mini-invasive technics, augmented osteoplasties, have been proposed for better long-term consolidation. The aim of this review is to detail the augmented osteoplasty techniques described in the literature and to report their safeties and efficacies to prevent pathological fracture of the proximal femur. A PubMed research found 8 studies that evaluated augmented osteoplasty of the proximal femur in cancer patients. All devices demonstrate adequate safety and low rate of secondary pathological fractures.

Thermal Ablation Combined with Selective Transarterial Embolization of Centrally Located Renal Cell Carcinomas Measuring 3 cm or Larger.

PURPOSE: The purpose of this study was to evaluate the long-term outcomes of patients with centrally located renal cell carcinomas (RCC) measuring 3 cm or larger, treated by a standardized transarterial embolization protocol associated with percutaneous ablation. MATERIALS AND METHODS: This retrospective study included 11 patients (73% male, mean age 73.4 ± 6.5 years) with RCC and contraindications for surgery. All patients underwent a single session combining transarterial embolization with iodized oil and subsequent thermal percutaneous ablation. Primary and secondary local tumor control were analyzed, defined as absence of any contrast enhancing nodular lesion in the treated area after a single or percutaneous re-treatment session, respectively. RESULTS: Mean tumor size was 3.5 ± 0.3 cm (range 3-4 cm) with a mean R.E.N.A.L. nephrometry score ((R)adius; (E)xophytic, endophytic properties; (N)earness to the collecting system; (A)nterior, posterior; (L)ocation relative to the polar line) of 8 ± 0.9 (range 7-9). Nearness to the collecting system was 4-7 mm in two patients (18%) and ≤ 4 mm in nine patients (82%). After a mean follow-up of 5.2 ± 2.5 years primary and secondary local tumor control rate were 82% and 100%, respectively. No change in serum creatinine levels and glomerular filtration rate was observed compared to pre-treatment values. CONCLUSION: A combined treatment of selective transarterial embolization and percutaneous ablation of large centrally located RCC (> 3 cm) is safe, feasible and can achieve excellent oncological long-term results. Larger prospective studies are needed.

Prostate Artery Embolization: Challenges, Tips, Tricks, and Perspectives.

Prostatic artery embolization (PAE) consists of blocking the arteries supplying the prostate to treat benign prostate hypertrophia (BPH). Its effectiveness on both urinary symptoms and flowmetric parameters has now been amply demonstrated by around a hundred studies, including several randomized trials. The main advantage of this procedure is the very low rate of urinary and sexual sequelae, including ejaculatory, with an excellent tolerance profile. The arterial anatomy is a key element for the realization of PAE. Its knowledge makes it possible to anticipate obstacles and prevent potential complications related to nontarget embolization. Nontarget embolization can occur with a small intraprostatic shunt or reflux and has no consequences except some local inflammation symptoms that resolve in a couple of days. Nevertheless, some situations with large arterial shunts arising from the prostatic artery must be recognized (accessory rectal, bladder, or pudendal branches), and must imperatively be protected before embolization, at the risk of exposing oneself to otherwise ischemic complications that are more severe, such as bladder necrosis and skin or mucosal necrosis. This article offers a step-by-step review of the various anatomical and technical key points to ensure technical and clinical success, while avoiding the occurrence of adverse events.

Using prostate contrast retention (PCR) as the procedural endpoint in prostatic artery embolization for benign prostatic hyperplasia.

OBJECTIVES: The failure rate following prostate artery embolization (PAE) is around 20%, which may in part result from inadequate embolization. Prostate contrast retention (PCR) adequacy on immediate post-embolization cone-beam CT may provide better assessment of embolization completeness than arterial contrast stasis seen on fluoroscopy alone. The aim of this study was to evaluate outcomes of PAE using PCR adequacy as the procedural endpoint. METHODS: A retrospective cohort study of all PAE cases using this technique at a single large volume center was conducted. Following initial embolization of the main prostatic arteries, if PCR was inadequate, additional embolization was performed. Technical success (adequate PCR) was defined as > 75% global prostate gland contrast staining. Clinical success was determined in accordance to CIRSE standards of practice. RESULTS: One hundred sixty-five patients (mean age 68 ± 8.4 years) underwent PAE from June 2017 to March 2019. Technical and clinical success rates were 98.8% and 96.4% respectively. Clinical success rate was significantly higher in patients with adequate PCR. International Prostate Symptom Scores (IPSS) and Quality of Life (QoL) scores significantly improved at 1-, 3-, 6-, and 12-month follow-up when compared to baseline. Prostate volume (PV) and post-voiding residual bladder volume were significantly reduced at 3, 6, and 12 months in comparison to baseline. Mild (Clavien-Dindo grade I/II) and moderate (grade III) complication rates were 12.1% and 3.6% respectively. CONCLUSIONS: By using PCR adequacy as a guide to determine the procedure endpoint for PAE, it may be possible to achieve more complete embolization and thus higher clinical success rates. KEY POINTS: • By using PCR adequacy as a guide to determine the procedure endpoint for PAE, it may be possible to achieve more complete embolization and thus higher clinical success rates.

Image-guided Percutaneous Fixation with Internal Cemented Screws of Impending Femoral Neck Pathologic Fractures in Patients with Metastatic Cancer: Safety, Efficacy, and Durability.

Background Prophylactic image-guided procedures performed by interventional radiologists for impending pathologic fractures are becoming more pertinent, as patients with metastatic cancer have extended overall survival because of advanced therapies. Purpose To evaluate the efficacy, safety, and palliative durability of collimated-beam CT-guided percutaneous fixation with internal cemented screws (FICS) for impending pathologic fractures of the femoral neck. Materials and Methods This single-institute retrospective study examined all patients with metastatic cancer treated between February 2010 and October 2019 with collimated-beam CT-guided percutaneous FICS procedures for preventive consolidation of impending femoral neck pathologic fractures. The short-term palliative efficacy was assessed through comparison of visual analog scale (VAS) scores before and 1 month after FICS. A review of cross-section imaging and clinic reports identified any procedural complications. Long-term consolidation efficacy was defined as the absence of any screw dislodgement or development of a pathologic fracture at completion of the study. The Wilcoxon test was used for the mean comparison of paired nonparametric variables. Results Sixty-one consecutive patients (mean age, 59 years ± 11 [standard deviation]; 35 women) underwent preventive FICS for consolidation of impending pathologic femoral neck fracture with a mean follow-up of 533 days ± 689. Two patients died of cancer within the first month. Complications were limited to three self-resolving hematomas. The mean VAS score decreased 1 month after FICS from 4.2 ± 3.2 to 1.8 ± 2.0 (P < .001). The long-term consolidation efficacy was 92% (54 of 59 patients), with three of 59 patients (5%) subsequently developing fractures despite FICS and an additional two of 59 patients (3%) with durable FICS undergoing definitive total hip arthroplasty surgery because of local tumor progression. Conclusion Percutaneous fixation with internal cemented screws as performed by the interventional radiologist is a safe nonsurgical treatment that provides an effective palliative result and durable prevention for impending pathologic fractures of the femoral neck. © RSNA, 2020 Online supplemental material is available for this article.

Safety and Efficacy of Multilevel Thoracolumbar Vertebroplasty in the Simultaneous Treatment of Six or More Pathologic Compression Fractures.

PURPOSE: To assess the safety and efficacy of multilevel thoracolumbar vertebroplasty in the simultaneous treatment of ≥ 6 painful pathologic compression fractures. MATERIALS AND METHODS: Retrospective review was conducted of 50 consecutive patients treated with vertebroplasty for ≥ 6 pathologic compression fractures in a single session for pain palliation at a tertiary single cancer center from 2015 to 2019. Outcomes measured included procedural safety according to Common Terminology Criteria for Adverse Events (CTCAE), change in 4-week postprocedure back pain by numeric rating scale (NRS), comparison of daily opioid medication consumption, and development of skeletal-related events. RESULTS: A total of 397 pathologic compression fractures were treated during 50 sessions (mean, 7.9 per patient ± 1.5). Mean procedure duration was 162 minutes ± 35, mean postoperative hospitalization duration was 1.6 days ± 0.9, and mean follow-up duration was 401 days ± 297. Seven complications were recorded, including 1 case of symptomatic polymethyl methacrylate pulmonary embolism. No major complications (CTCAE grade 4/5) were reported. NRS pain score was significantly decreased (5.0 ± 1.8 vs 1.7 ± 1.4; P < .0001), with a mean score decrease of 3.3 points (66%). Opioid agent use decreased significantly (76 mg/24 h ± 42 vs 45 mg/24 h ± 37; P = .0003), with a mean decrease of 30 mg/24 h (39%). Skeletal-related events occurred in 7 patients (14%). CONCLUSIONS: Multilevel vertebroplasty for ≥ 6 pathologic compression fractures is safe and provides significant palliative benefit when performed simultaneously.

Lung microwave ablation - an in vivo swine tumor model experiment to evaluate ablation zones.

PURPOSE: To evaluate microwave ablation (MWA) algorithms, comparing pulsed and continuous mode in an in vivo lung tumor mimic model. MATERIALS AND METHODS: A total of 43 lung tumor-mimic models of 1, 2 or 3 cm were created in 11 pigs through an intra-pulmonary injection of contrast-enriched minced muscle. Tumors were ablated under fluoroscopic and 3D-CBCT-guidance using a single microwave antenna. Continuous (CM) and pulsed mode (PM) were used. According to tumor size, 3 different algorithms for both continuous and pulsed mode were used. The ablation zones were measured using post-procedural 3D-CBCT and on pathologic specimens. RESULTS: Two radiologists measured the ablation zones on CBCT and they significantly correlated with macroscopic and microscopic pathological findings: r = 0.75 and 0.74 respectively (p < 0.0001) (inter-observer correlation r = 0.9). For 1, 2 and 3 cm tumors mimics lesions (TMLs), mean maximal and transverse ablation diameters were 3.6 [Formula: see text] 0.3 × 2.2 [Formula: see text] 0.3 cm; 4.1 [Formula: see text] 0.5 × 2.6 [Formula: see text] 0.3 cm and 4.8 [Formula: see text] 0.3 × 3.2 [Formula: see text] 0.3 cm respectively using CM; And, 3.0 [Formula: see text] 0.2 × 2.1 [Formula: see text] 0.2 cm; 4.0 [Formula: see text] 0.4 × 2.7 [Formula: see text] 0.4 cm and 4.6 [Formula: see text] 0.4 × 3.2 [Formula: see text] 0.4 cm respectively for PM, without any significant difference except for 1 cm TMLs treated by PM ablation which were significantly smaller (p = 0.009) The sphericity index was 1.6, 1.6, 1.5 and 1.4, 1.5, 1.4 at 1, 2 and 3 cm for CM and PM respectively, p = 0.07, 0.14 and 0.13 for 1, 2 and 3 cm tumors mimics. CONCLUSION: Microwave ablation for 1-3 cm lung tumors were successfully realized but with a moderate reproducibility rate, using either CM or PM. Immediate post ablation CBCT can accurately evaluate ablation zones.

Multi-Level Vertebroplasty for 6 or More Painful Osteoporotic Vertebral Body Compression Fractures Performed in the Same Procedural Setting: A Safety and Efficacy Report in Cancer Patients.

PURPOSE: To assess safety and efficacy of multi-level vertebroplasty, when treating 6 or more levels in the same procedural setting for the management of osteoporotic vertebral compression fractures (oVCF) in cancer patients. MATERIALS AND METHODS: Single institution retrospective review from 2015 to 2019 of patients treated for multi-level oVCF in a single session procedural setting by vertebroplasty of 6 or more levels. Procedure outcomes collected included procedural complications, pre- and 4 week post-procedure pain score by numeric rating scale, opioid usage, and vertebral height changes. RESULTS: In total, 197 vertebral levels were treated in 24 procedures (mean 8.2 ± 1.8 levels). Mean procedure duration was 167 + / - 41 min, and mean postoperative hospitalization duration was 2.1 + / - 1.9 days. Four grade I or II complications occurred according to CIRSE classification. Two patients had a symptomatic pulmonary cement embolism; although there was no statistical difference between pre- and postoperative mean blood saturation (95.9 + / - 1.7% and 94.8 + / - 2.0%, respectively, p = 0.066). Pain score significantly improved after treatment (6.5 ± 1.3 vs 3.2 + / - 1.4, p < 0.0001) with a mean decrease of 3.3 (51%). Post-procedure daily opioid use also significantly improved (mean 35.8 + / - 36.8 mg/24 h vs 18.5 + / - 27.8 mg/24 h, p = 0.0089), with a mean decrease of 17.3 mg/24 h (48%). Refracture was found in 2 of 105 levels treated (1.9%), and no difference was found in thoraco-lumbar height and angulation. Five patients experienced new painful fractures at a non-treated level. CONCLUSION: Multi-level vertebroplasty for 6 or more levels is a safe and effective treatment for the management of multi-level oVCF in cancer patients.

Multicenter Study of Metastatic Lung Tumors Targeted by Interventional Cryoablation Evaluation (SOLSTICE).

OBJECTIVE: To assess the safety and local recurrence-free survival in patients after cryoablation for treatment of pulmonary metastases. METHODS: This multicenter, prospective, single-arm, phase 2 study included 128 patients with 224 lung metastases treated with percutaneous cryoablation, with 12 and 24 months of follow-up. The patients were enrolled on the basis of the outlined key inclusion criteria, which include one to six metastases from extrapulmonary cancers with a maximal diameter of 3.5 cm. Time to progression of the index tumor(s), metastatic disease, and overall survival rates were estimated using the Kaplan-Meier method. Complications were captured for 30 days after the procedure, and changes in performance status and quality of life were also evaluated. RESULTS: Median size of metastases was 1.0 plus or minus 0.6 cm (0.2-4.5) with a median number of tumors of 1.0 plus or minus 1.2 cm (one to six). Local recurrence-free response (local tumor efficacy) of the treated tumor was 172 of 202 (85.1%) at 12 months and 139 of 180 (77.2%) at 24 months after the initial treatment. After a second cryoablation treatment for recurrent tumor, secondary local recurrence-free response (local tumor efficacy) was 184 of 202 (91.1%) at 12 months and 152 of 180 (84.4%) at 24 months. Kaplan-Meier estimates of 12- and 24-month overall survival rates were 97.6% (95% confidence interval: 92.6-99.2) and 86.6% (95% confidence interval: 78.7-91.7), respectively. Rate of pneumothorax that required pleural catheter placement was 26% (44/169). There were eight grade 3 complication events in 169 procedures (4.7%) and one (0.6%) grade 4 event. CONCLUSION: Percutaneous cryoablation is a safe and effective treatment for pulmonary metastases.

CT guidance assisted by electromagnetic navigation system for percutaneous fixation by internal cemented screws (FICS).

PURPOSE: To evaluate electromagnetic navigation system (ENS) for percutaneous fixation by internal cemented screw (FICS) under CT guidance. BACKGROUND: FICS is a recently developed modality that consists in inserting screws, under imaging guidance, into bone through a minimal skin incision. FICS recently showed good efficacy for the palliation or prevention of pathologic fractures of the pelvic ring and femoral neck. MATERIALS AND METHODS: In this single-center retrospective study, we reviewed all consecutive cancer patients treated with percutaneous FICS under ENS-assisted CT guidance for the prevention or palliation of pelvic or femoral neck fractures. The primary endpoint was technical success. Secondary endpoints were screw placement accuracy (defined by proximal deviation p, distal deviation d, and angle deviation θ), radiation dose exposure, number of CT acquisitions, duration of procedures, and complications. RESULTS: Mean duration of FICS procedures was 111 ± 51 min. Mean post-procedure hospitalization length was 2.1 days. Technical success was achieved in 48 cases (96%) with a total of 76 screws inserted. Mean distance p, mean distance d, and mean angle θ were respectively 8.0 ± 4.5 mm, 7.5 ± 4.4 mm, and 5.4 ± 2°. Angle θ accuracy was higher for screws with a craniocaudal angulation of less than 20° (4.4° vs 6.4°, p = 0.02). The mean number of CT acquisitions during procedures was 6.4 ± 3.0. The mean dose length product was 1524 ± 953 mGy cm and the mean dose area product was 12 ± 8 Gy cm2. Five complications occurred in 4 patients. CONCLUSION: CT guidance assisted by ENS is an effective approach for percutaneous FICS. KEY POINTS: • ENS-assisted CT enables screw insertion in the pelvic ring and femoral neck, with a wide range of trajectories, even when a significant craniocaudal angulation is required. • ENS-assisted CT can be used as an alternative to CBCT guidance for percutaneous fixation by internal cemented screw. • ENS-assisted CT provides high technical success rate with excellent placement accuracy.

Percutaneous Fixation by Internal Cemented Screws of the Sternum.

PURPOSE: To evaluate the feasibility, efficacy and safety of sternal percutaneous fixation by internal cemented screw (FICS) using fluoroscopy and/or CT needle guidance. MATERIALS AND METHODS: This retrospective single-center study analyzed 9 consecutive cancer patients managed with percutaneous FICS for sternal fracture fixation or osteolytic metastasis consolidation, from May 2014 to February 2019. Eastern Cooperative Oncology Group performance status, Numeric Pain Rating Scale (NPRS) and opioid use were studied preoperatively and postoperatively. Sternal images at last follow-up appointment were also collected. RESULTS: Among the 9 patients, 7 had a sternal fracture with 5 being displaced. The technical feasibility was 100%. Both NPRS score significantly decreased from 5.6/10 ± 2.8 to 1.1/10 ± 1.6, and analgesic consumption was significantly improved (p = 0.03) after intervention. No post-procedural complications requiring surgical correction or screw displacement occurred after a mean imaging follow-up that exceeded 1 year (mean follow-up duration, 401.8 days ± 305.8). CONCLUSION: Image-guided sternal percutaneous FICS is feasible and safe. It reduces pain and analgesic consumption related to pathologic fracture of the sternum.

Image-guided lung metastasis ablation: a literature review.

Purpose: To review the available options of percutaneous ablation of lung metastasis. Methods: General indications, prognostic factors, and image guidance of percutaneous lung ablations were reviewed. Specificities, technical aspects, advantages and limitations of each technic were highlighted. Complications and follow up where also reviewed. Results: Image-guided, percutaneous ablation is of interest for patients with a limit number (<3-5) small metastases (<2-3 cm). Other predictive factors have been reported such as the disease-free interval, the primary tumor, or the proximity with large vessels or bronchus. Radiofrequency ablation (RFA) is the most reported technic, with local control rate >90% for small tumors, and a very low complication rate. Microwave (MWA) and cryoablation are alternative technics developed in the last 15 years to overcome RFA limitations, with encouraging results. Larger ablations zones and less heat sink effect have been described with MWA. On the other hand, cryoablation allows painless treatments under conscious sedation and/or local anesthesia, high accessibility of difficult locations and promising results on prospective multicenter series. Although irreversible electroporation (IRE) could be used for lesions close to main blood vessels as it is not limited by the heat sink effect and does not have significant effects on connective tissue, allowing to treat lesions near to vital organs, preliminary results for lung metastasis are disappointing. Conclusion: Percutaneous ablation of lung metastases, whatever technic is used, is feasible, with high local control rate, and acceptable complication rate. Although indications seem clear enough, validation through controlled trials is mandatory.

Early detection with MRI of incomplete treatment of spine metastases after percutaneous cryoablation.

OBJECTIVES: To evaluate post-ablation MRI for the detection of incompletely treated spinal osseous metastases (SOM) after cryoablation and to propose a post-ablation imaging classification. METHODS: After IRB consent, all patients treated with cryoablation of SOM between 2011 and 2017 having at least 1-year minimum follow-up and a spine MRI within 4 months after cryoablation were retrospectively included. A classification of MRI images into four types was set up. The primary endpoint of our study was to assess the diagnostic performance of the post-ablation MRI. The secondary endpoints were the 1-year complete treatment rate (CTR) and complications. RESULTS: Fifty-four SOMs in 39 patients were evaluated. Post-ablation MRI was performed with a median delay of 25 days after cryoablation. Images were evaluated by two independent readers according to the pre-established image classification. Sensitivity and specificity for the detection of residual tumor were 77.3% (95%CI = 62.2-88.5) and 85.9% (95%CI = 75.0-93.4), respectively. Types I, II, III, and IV of the classification were associated with a 1-year complete treatment in 100%, 83.3%, 35.7%, and 10% of cases, respectively. The 1-year CTR was 59.3% for all 54 metastases, and 95.8% for metastases measuring less than 25 mm and at least 2 mm or more away from the spinal canal. Two grade 3 and two grade 2 adverse events according to the CTCAE were reported. CONCLUSIONS: MRI after cryoablation is useful for the evaluation of the ablation efficacy. The classification of post-cryoablation MRI provides reliable clues for the prediction of complete treatment at 1 year. KEY POINTS: • MRI performed 25 days after cryoablation is useful to evaluate the efficacy. • The proposed classification provides a reliable clue for complete cryoablation. • Percutaneous cryoablation of spinal metastases is highly effective for lesions less than 25 mm in diameter and of at least 2 mm away from the spinal canal.