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The growing detection of papillary thyroid microcarcinomas (PTMCs) is paralleled by an increase in surgical procedures. Due to the frequent indolent nature, cost, and risk of surgery, active surveillance (AS) and ultrasound-guided minimally invasive treatments (MITs) are in suitable cases of incidental PTMC proposed as alternatives to thyroidectomy. Surgery and radioiodine are the established treatments for relapsing cervical differentiated thyroid carcinoma (DTC) metastases. But radioiodine refractoriness, risk of surgical complications, adverse influence on quality of life, or declining repeat surgery have led to AS and MIT being considered as alternatives for slow-growing DTC nodal metastases. Also, for distant radioiodine-refractory metastases not amenable to surgery, MIT is proposed as part of a multimodality therapeutic approach. The European Thyroid Association and the Cardiovascular and Interventional Radiological Society of Europe commissioned these guidelines for the appropriate use of MIT. Based on a systematic PubMed search, an evidence-based approach was applied, and both knowledge and practical experience of the panelists were incorporated to develop the manuscript and the specific recommendations. We recommend that when weighing between surgery, radioiodine, AS, or MIT for DTC, a multidisciplinary team including members with expertise in interventional radiology assess the demographic, clinical, histological, and imaging characteristics for appropriate selection of patients eligible for MIT. Consider TA in low-risk PTMC patients who are at surgical risk, have short life expectancy, relevant comorbidities, or are unwilling to undergo surgery or AS. As laser ablation, radiofrequency ablation, and microwave ablation are similarly safe and effective thermal ablation (TA) techniques, the choice should be based on the specific competences and resources of the centers. Use of ethanol ablation and high-intensity focused ultrasound is not recommended for PTMC treatment. Consider MIT as an alternative to surgical neck dissection in patients with radioiodine refractory cervical recurrences who are at surgical risk or decline further surgery. Factors that favor MIT are previous neck dissection, presence of surgical complications, small size metastases, and <4 involved latero-cervical lymph nodes. Consider TA among treatment options in patients with unresectable oligometastatic or oligoprogressive distant metastases to achieve local tumor control or pain palliation. Consider TA, in combination with bone consolidation and external beam radiation therapy, as a treatment option for painful bone metastases not amenable to other established treatments., Competing Interests: G.M.: consultancy from Elesta SrL, speaking fee from GE, Advisory Board for Boston Scientific. All other authors declare they have no conflicts of interest to declare., (Copyright © 2021 by S. Karger AG, Basel.)

Purpose: The purpose of this study was to retrospectively assess the safety profile of percutaneous image-guided screw fixation (PIGSF) for insufficiency, impending or pathological fractures., Materials and Methods: From July 2012 to April 2020, all consecutive patients who underwent PIGSF were retrospectively included in the study. Patient characteristics, fracture type, procedural data and complications were analyzed. Complications were divided into per-procedural, early (<24hours) and delayed (>24hours) and classified into minor (grade 1-2) and major complications (grade 3-5) according to Common Terminology Criteria for Adverse Events (CTCAE) v5.0., Results: A total of 110 fractures (40 insufficiency [36%], 53 pathological [48.5%] and 17 impending [15.5%] fractures) in 94 patients (48 women, 46 men; mean age, 62.7±12.7 [SD] years; age range: 32-88 years) were treated with PIGSF during 95 procedures. Twenty-four-hours follow-up was available for all patients, and>24-hours follow-up was available for 79 (79/110; 71.8%) fractures in 69 (69/94; 73.4%) patients. Per-procedural complications occurred in 3/110 fractures (2.7%, all minor). Early complications were reported in 4/110 fractures (3.6%, 1 major and 3 minor) and delayed ones in 14/79 fractures (17.7%, 5 major and 9 minor). The most frequent major delayed complication was infection (3/79; 3.8%)., Conclusion: The rate of per-procedural and early (within 24hours) complications following PIGSF is extremely low with most complications being minor, with major complications being delayed ones (>24hours)., (Copyright © 2021 Société française de radiologie. Published by Elsevier Masson SAS. All rights reserved.)

Purpose: To assess efficacy and safety of percutaneous cryoablation (CA) for advanced and refractory extra-abdominal desmoid tumors., Materials and Methods: This retrospective study reviewed 30 consecutive patients with symptomatic desmoid tumors evolving after "wait and watch" periods, and despite medical treatment, treated by CA between 2007 and 2019. Progression free survival (PFS), objective response rate, pain reduction (decreased of visual analogic scale pain (VAS)[Formula: see text] 3 or disappearance of pain), total volume lesion (TVL) and complications were documented. Kaplan Meier method was used to outline PFS. Paired sample t test was used to compare volume of tumors before treatment and at 1 and 3 year., Results: With a median follow-up of 18.5 months (range 6-93 months, interquartile range (IQR): 12-55), the PFS was 85.1% at 1 year and 77.3% at 3 years. Objective response was obtained for 80% of patients with a complete response for 43% patients. Pain reduction was obtained for 96.7% (95% confidence interval (95% CI): 90.3, 100) of patients. Median volume of desmoid tumor before treatment was 124.1cm 3 (range 2-1727cm 3 , IQR: 54-338cm 3 ). Median change of TLV after ablation was 66.6% (95% CI: 37.2, 72.3; p = 0.002) at 1 year and 76.4% (95% CI: 59.1, 89.8; p = 0.002) at 3 year. Adverse events rate was 36.6%, the most common was edema and temporary increase of pain in the days following CA. Four patients experienced a major complication (13.3%): 2 skin necrosis, 1 infection and 1 brachial plexopathy., Conclusion: CA is an effective treatment for advanced and refractory extra-abdominal desmoid tumor, that induces durable responses.

Purpose: To retrospectively report on safety, pain relief and local tumor control achieved with percutaneous ablation of sacral bone metastases., Materials and Methods: From February 2009 to June 2020, 23 consecutive patients (12 women and 11 men; mean age, 60±8 [SD] years; median, 60; range: 48-80 years) with 23 sacral metastases underwent radiofrequency (RFA) or cryo-ablation (CA), with palliative or curative intent at our institution. Patients' demographics and data pertaining to treated metastases, procedure-related variables, safety, and clinical evolution following ablation were collected and analyzed. Pain was assessed with numerical pain rating scale (NPRS)., Results: Sixteen (70%) patients were treated with palliative and 7 (30%) with curative intent. Mean tumor diameter was 38±19 (SD) mm (median, 36; range: 11-76). External radiation therapy had been performed on five metastases (5/23; 22%) prior to ablation. RFA was used in 9 (39%) metastases and CA in the remaining 14 (61%). Thermo-protective measures and adjuvant bone consolidation were used whilst treating 20 (87%) and 8 (35%) metastases, respectively. Five (22%) minor complications were recorded. At mean 31±21 (SD) (median, 32; range: 2-70) months follow-up mean NPRS was 2±2 (SD) (median, 1; range: 0-6) vs. 5±1 (median, 5; range: 4-8; P<0.001) at the baseline. Three metastases out of 7 (43%) undergoing curative ablation showed local progression at mean 4±4 (SD) (median, 2; range: 1-8) months follow-up., Conclusion: Percutaneous ablation of sacral metastases is safe and results in significant long-lasting pain relief. Local tumor control seems sub-optimal; however, further investigations are needed to confirm these findings due to paucity of data., (Copyright © 2021 Société française de radiologie. Published by Elsevier Masson SAS. All rights reserved.)

Purpose: To present the technique of combined temperature monitoring and hydrodissection of the anterior epidural space during thermal ablation in the thoracic spine., Materials and Methods: Data from 8 patients were retrieved retrospectively with thoracic spinal metastases located near the posterior wall of the vertebral body. Thermal ablation was performed with temperature monitoring and hydrodissection of the anterior epidural space., Results: Technical success, defined as a fulfilled ablation protocol without changes of the temperature of the epidural space below 10°/above 45° that could not be controlled by active hydrodissection, was 100%. The mean time to deploy the thermosensor was 19.5 ± 4.8 min (range 13-35). There was one post-operative transient intercostal neuralgia. No spinal cord or nerve root injuries arose. Two local recurrences occurred at a mean follow-up of 20 ± 9 months., Conclusion: Transosseous temperature monitoring of the anterior epidural space in the thoracic spine is a feasible technique and seems safe.

Aim: To systematically review microwave ablation (MWA) protocols, safety, and clinical efficacy for treating bone tumors., Materials and Methods: A systematic literature search was conducted using PubMed, the Cochrane Library, EMBASE, and Web of Science database. Data concerning patient demographics, tumor characteristics, procedure, complications, and clinical outcomes were extracted and analyzed., Results: Seven non-comparative studies (6 retrospective, 1 prospective) were included accounting for 249 patients and 306 tumors (244/306 [79.7%] metastases; 25/306 [8.2%] myelomas, and 37/306 [12.1%] osteoid osteomas [OO]). In malignant tumors, MWA power was 30-70 W (except in one spinal tumors series where a mean power of 13.3 W was used) with pooled mean ablation time of 308.3 s. With OO, MWA power was 30-60 W with mean ablation time of 90-102 s. Protective measures were very sporadically used in 5 studies. Additional osteoplasty was performed in 199/269 (74.0%) malignant tumors. Clinically significant complications were noted in 10/249 (4.0%) patients. For malignant tumors, estimated pain reduction on the numerical rating scale was 5.3/10 (95% confidence intervals [95%CI] 4.6-6.1) at 1 month; and 5.3/10 (95% CI 4.3-6.3) at the last recorded follow-up (range 20-24 weeks in 4/5 studies). For OO, at 1-month follow-up, effective pain relief was noted in 92.3-100% of patients., Conclusion: MWA is effective in achieving pain relief at short- (1 month) and mid-term (4-6 months) for painful OO and malignant bone tumors, respectively. Although MWA seems safe, further prospective studies are warranted to further assess this aspect, and to standardize MWA protocols., Key Points: • Large heterogeneity exists across literature about ablation protocols used with microwave ablation applied for the treatment of benign and malignant bone tumors. • Although microwave ablation of bone tumors appears safe, further studies are needed to assess this aspect, as current literature does not allow definitive conclusions. • Nevertheless, microwave ablation is effective in achieving pain relief at short- (1 month) and mid-term (4-6 months) for painful osteoid osteomas and malignant bone tumors, respectively.

Purpose: To describe the technique of percutaneous image-guided anterior screw fixation of the odontoid process in five patients using hydrodissection of the jugulo-carotid and pre-vertebral spaces., Methods and Materials: Between 03/2018 and 03/2020, five patients from two university hospitals underwent a percutaneous image-guided anterior screw fixation of the odontoid process for one pathological fracture, two impending fractures and two traumatic fractures of the dens. Technical success was defined as a satisfactory positioning of the screw in the odontoid. Detailed data with the number and type of needles required, the time to perform hydrodissection, the volume of fluid used, the time for bone access, the size and lengths of the screws used, technical success, complications, clinical outcomes and follow-up were retrospectively assessed., Results: Technical success was achieved in 100% (5/5 cases), with a mean volume of hydrodissection of 218 ± 8.4 mL (range 210-230). Mean total procedure time was 112 ± 34 min (range 70-160). The lengths of the screws ranged from 30 mm to 55 mm. Additional cementoplasty was performed in the three malignant cases. VAS scores dropped on a 10-point scale from mean 5.8 ± 2.2 pre-procedure to 0.8 ± 0.4 after the procedure. No major complication occurred., Conclusion: Percutaneous image-guided anterior screw fixation of the odontoid process using hydrodissection of the jugulo-carotid and pre-vertebral spaces is technically feasible and seems safe.

Objectives: Magnetic resonance imaging guidance has been sporadically reported for renal tumor cryoablation (CA); therefore, clinical experience with this modality is still limited.The aim of this study is to retrospectively analyze our 10-year experience with renal tumor CA performed on a 1.5 T magnetic resonance imaging unit with the intent of reporting procedural safety and oncologic outcomes., Materials and Methods: We included 143 patients (102 men; 41 women; median age, 73 years; range, 34-91 years) with 149 tumors (median size, 2.6 cm; range, 0.6-6.0 cm), treated between 2009 and 2019. Patient, tumor, procedure, and follow-up data were collected and analyzed. The Kaplan-Meier method was used to estimate local recurrence-free (LRFS), metastasis-free (MFS), disease-free (DFS), cancer-specific, and overall (OS) survival. Univariate and multivariate models were used to identify factors associated with complications, LRFS, MFS, DFS, and OS., Results: The overall complication rate was 10.7% (16/149 tumors), with 1 major (1/149 [0.7%]; 95% confidence interval, 0.0%-3.7%) hemorrhagic complication. Other minor complications (15/149 [10.1%]; 95% confidence interval, 0.6%-16.1%) did not include any cases of injury to nearby organs. There were no factors associated with complications.Five-year estimates of LRFS (primary/secondary), MFS, DFS, cancer-specific survival, and OS were 82.8%/91.5%, 91.1%, 75.1%, 98.2%, and 89.6%, respectively. Increasing tumor size (hazard radio [HR], 1.8; P = 0.02) and intraparenchymal tumor location (HR, 5.6; P < 0.01) were associated with lower LRFS; increasing patient's age (HR, 0.5; P = 0.01), high tumor grade (HR, 23.3; P < 0.01) and non-clear-cell/nonpapillary histology (HR, 20.1; P < 0.01) with metastatic disease; and high tumor grade (HR, 3.2; P = 0.04) with lower DFS., Conclusion: Magnetic resonance imaging-guided CA of renal tumors is associated with acceptable morbidity and high survival estimates at 5-year follow-up. Given the absence of complications resulting from injuries to nearby organs, further studies are required to evaluate whether the potential reduced incidence of these adverse events justifies large-scale implementation of this interventional modality., Competing Interests: Conflicts of interest and source of funding: Drs Gangi and Garnon are advisors to BTG., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: To report the rate of fragmentation of the cement plug following percutaneous cementoplasty with polymethylmethacrylate (PMMA) in the bony pelvis (i.e., pelvic bones or sacrum)., Materials and Methods: Post-interventional and follow-up CT scans of 56 patients (36 men; mean age of 68.4 ± 15.4) with a total of 98 percutaneous cementoplasty procedures were analyzed. Indications for treatment included painful malignant tumors (42.9%; 42/98) and insufficiency fractures (57,1%; 56/98). Fragmentation of PMMA was recorded for each cement plug., Results: Mean interval between the procedure and the last available CT scan was 29.3 ± 18.8 months. There was no significant difference between the length of follow-up of malignant lesions (27.6 ± 15.1 months) and insufficiency fractures (29 ± 20.5 months) (p = 0.69). Fragmentation was diagnosed following 2/98 (2%) procedures, both in the malignant lesions group. The time intervals between the procedure and the first visualization of cement fragmentation were 6 for the first and 24 months for the second patient., Conclusion: Fragmentation of the PMMA plug following percutaneous cementoplasty in the bony pelvis is a rare finding at midterm follow-up. It was only observed in cementoplasty performed in malignant lesions and seems to be more a consequence of local mechanical stresses than as a result of porosity.

Objective: To report our experience of percutaneous image-guided cryoablation of renal tumors located within 10 mm of the pyeloureteric junction (PUJ) and/or ureter, with hydrodissection as a stand-alone thermoprotective technique., Materials and Methods: All patients who were offered combined hydrodissection and cryoablation of the PUJ/ureter to treat stage-1 renal cell carcinoma were retrospectively reviewed. Data regarding patients, lesions, and outcomes were collected., Results: Twenty tumors in 20 patients (13 males:7 females) with a mean age of 74.4 ± 7.5 were included. Mean tumor size was 27.6 ± 6.4 mm. Nearby vulnerable structure(s) were identified as the ureter in 5/20 cases, the PUJ in 8/20 cases and both the PUJ and the ureter in the remaining 7/20 cases (35%) cases. Mean minimal distance between the tumor and the vulnerable organ(s) was 4.8 ± 2.6 mm (range 0-10). A mean of 1.7 ± 0.6 spinal needles were used per intervention with a mean time to complete hydrodissection of 18.6 ± 13.4 min. Primary and secondary technical efficacy rates were 90% and 95%, respectively. Mean follow-up was 23.1 ± 9.2 months. There were no immediate or delayed complications, in particular no urothelial strictures. Two tumor recurrences occurred during follow-up, with a time to disease progression of 13 and 31 months, respectively., Conclusion: hydrodissection of the PUJ/ureter to prevent thermal injury during cryoablation is an effective technique and does not seem to compromise the efficacy of ablation at short or mid-term follow-up.

Objectives: Percutaneous vertebroplasty (PV) of the cervical spine has been traditionally performed with a trans-oral or antero-lateral approach. The posterior trans-pedicular approach (PTPA) has been sporadically reported. Therefore, the aim of this study is to retrospectively assess the technical feasibility, safety, and clinical outcomes of cervical PV performed with a PTPA., Methods: All consecutive patients undergoing PV in cervical levels with PTPA (under general anesthesia and computed tomography [CT] guidance) from January 2008 to November 2019 were identified. The following data were collected: patients' demographics; indication for PV; vertebral level features; procedure-related variables; and clinical outcomes including complications and pain relief., Results: Thirty-two patients (18 females, 14 males; mean age 61.1 ± 13.2 years, range 36-88) were included accounting for 36 vertebrae. Three vertebrae (3/36, 8%) were referred due to an underlying traumatic fracture, the remaining (33/36, 92%) due to a painful lytic tumor. Technical success was 97% (35/36 levels). Mean time required to deploy the trocar was 23 ± 11 min (range 7-60). Extra-vertebral asymptomatic cement leakage was observed in 3/35 (9%) vertebral levels. One patient (1/32, 3%) developed an acute cardiogenic pulmonary edema requiring admission in the intensive care unit; another patient (1/32, 3%) developed localized infection to the skin entry site, which was managed conservatively. At 1-month follow-up, the mean pain in the study population was 1.0 ± 1.1 (range 0-4/10) vs 6.2 ± 1.4 (range 4-9/10) at baseline (p < 0.05)., Conclusions: Cervical PV performed via a CT-guided PTPA is technically feasible, safe, and results in effective pain relief., Key Points: • Percutaneous vertebroplasty (PV) is a well-established technique for the treatment of benign and malignant compression fractures. • Common PV approaches used for cervical vertebrae include the trans-oral, antero-lateral, lateral, and sporadically the posterior trans-pedicular approach. • Retrospective analysis of our 11-year experience with the posterior trans-pedicular approach used for cervical vertebrae proved that such approach was safe and effective.

Objectives: To retrospectively evaluate diagnostic accuracy and complications of magnetic resonance imaging (MRI)-guided biopsy of radiologically indeterminate solid renal masses (RM)., Methods: Electronic records of all consecutive patients undergoing MRI-guided biopsy of solid RM (using free-breathing T2-BLADE and BEAT-IRTTT sequences) between April 2014 and October 2018 were reviewed; 101 patients (69 men, 32 women; median age 68 years; range 32-76) were included. Patient and RM characteristics, procedural details/complications, pathologic diagnosis, and clinical management were recorded. Diagnostic accuracy was calculated on an intention-to-diagnose basis. Diagnostic yield was also evaluated. Multi-variable analysis was performed for variables with p < .20, including patient age/sex; RM size/location/contact with vascular pedicle, RENAL score, number and total length of biopsy samples, and biopsy tract embolization, to determine factors associated with diagnostic samples, diagnostic accuracy, and complications., Results: Median RM size was 2.4 cm (range 1-8.4 cm). There were 86 (85%; 95%CI 77-91%) diagnostic and 15 (15%; 95%CI 9-23%) non-diagnostic samples; 6/15 (40%) non-diagnostic biopsies were repeated with 50% malignancy rate. Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were 96% (95%CI 89-99%), 100% (95%CI 77-100%), 100% (95%CI 95-100%), 82% (95%CI 57-96%), and 97% (95%CI 90-99%), respectively. Primary and secondary diagnostic yields were 85% (95%CI 77-91%) and 91% (95%CI 84-96%), respectively. Seven (7%; 95%CI 1-10%) complications were observed. No tested variables were associated with diagnostic samples, diagnostic accuracy, or complications., Conclusions: MRI-guided biopsy of solid RM is associated with high diagnostic accuracy and low complication rate. The technique might be helpful for inaccessible tumors., Key Points: • MRI-guided biopsy of radiologically indeterminate solid renal masses (RM) appears safe, with a low rate of minor self-limiting hemorrhagic complications. • Diagnostic accuracy and primary/secondary diagnostic yield are high and appear similar to reported estimates for US- and CT-guided RM biopsy. • MRI guidance may be particularly useful for RM with poor conspicuity on US and CT, for relatively inaccessible tumors (e.g., tumors requiring double-oblique steep-angled approaches), and for young patients or those with renal failure.

Purpose: To retrospectively analyze our interventional radiology outpatient clinics (IROC) for referral patterns, impact on interventional practice, and patient satisfaction., Materials and Methods: Consultations performed between 2011 and 2019 were extracted. The two consecutive years with the highest number of consultations (n 2018  = 1426; n 2019  = 1595) were compared for unattended consultations (i.e., scheduled consultations with patients not showing-up); initial/follow-up consultations; hospital clinician/general practitioner referrals; initial consultations with radiologists not recommending interventions; procedural conversion rate (PCR; i.e., No. initial consultations resulting in interventions over the total number of initial consultations performed for the same clinical indication). A survey was conducted in 159 patients to determine their satisfaction., Results: Consultations increased from 2011 to 2019 by 130%. In 2018-2019, the number of unattended consultations was stable (7.0% vs 6.6%; P = .68). The referrals were for back pain (42.2%), interventional oncology (40.5%), and arteriovenous malformations (9.0%). For back pain, in 2019, there were fewer consultations with radiologists not recommending interventions and increased PCR compared to 2018 (11.9% vs. 17.7%; 88.1% vs. 82.3%; respectively; P = .01). For interventional oncology, follow-up consultations and general practitioner referrals increased in 2019 compared to 2018 (43.0% vs 35.3%; P = .01; 24.4% vs. 12.7%; P < .01; respectively). No other changes were noted. Cumulative 2018-2019 PCR was ≥ 85.4%. 99.2% responders highly appreciated their IROC experience. Quality of secretarial and medical services were the main aspects evaluated to rate the experience with IROC., Conclusion: IROC results in high PCR. Recent changes in referral/impact on IR practice were noted with patients referred for back pain and interventional oncology., Level of Evidence Iv: Level 4, Case Series.

Purpose: To investigate the safety and clinical efficacy of bipolar radiofrequency ablation (b-RFA) with increased (>70°C) target temperature for the treatment of spine metastases with the intent of achieving pain relief or local tumor control., Materials and Methods: Thirty-one patients with a total of 37 metastases who were treated with b-RFA with increased temperature and vertebroplasty from January 2016 to May 2019 were retrospectively included. There were 20 women and 11 men with a mean age of 62.4±10.5 (SD) years (range: 40-78years). Patients and metastases characteristics, procedure details and clinical outcomes were analyzed., Results: Metastases were predominantly located in lumbar (22/37; 59.5%) or thoracic spine (13/37; 35.1%). Mean target temperature was 88.4±3.5 (SD) °C (range: 70-90°C). Technical success was 100% (37/37 metastases). One (1/37; 2.7%) major complication unrelated to b-RFA was reported. One (1/37; 2.7%) metastasis was lost to follow-up. Favorable outcome was noted in patients receiving b-RFA for pain management (16/20 metastases; 80%; mean follow-up, 3.4±2.9 [SD] months) or with oligometastatic/oligoprogressive disease (6/6 metastases; 100%; mean follow-up, 5.0±4.6 [SD] months). In patients receiving b-RFA to prevent complications, favorable outcome was noted in 6/10 metastases (60%; mean follow-up, 3.8±4.8 [SD] months)., Conclusions: B-RFA with increased target temperature has an excellent safety profile and results in high rates of pain relief and local metastasis control in patients with oligometastatic/oligoprogressive disease. Suboptimal results are achieved in patients receiving b-RFA to prevent complications related to the growth of the index tumor., (Copyright © 2020. Published by Elsevier Masson SAS.)

Aim: To report the technique of percutaneous double oblique anterior access to the acetabulum and evaluate its feasibility and safety., Materials and Methods: Pelvic computed tomography (CT) examinations of 60 patients (30 men and 30 women; mean age 62.6±13.2 years) were retrieved randomly from the picture archiving and communication system (PACS). A virtual intraosseous trajectory was defined on both sides on the axial CT images with the entry point marked 1 cm above the anterosuperior iliac spine and the endpoint defined just above the level of the ischial spine at the midpoint of the posterior acetabulum. Patient age, sagittal oblique angulation, axial oblique angulation, length of intraosseous trajectory, distance from the hip joint, thickness of the iliac bone cortex, and intervening structure(s) between the skin and the bone entry points were recorded., Results: The mean sagittal and axial oblique angulations were 34.2±4.5° and 31.5±6.7°, respectively, and mean length of the intraosseous trajectory was 11.8±0.9 cm. The axial oblique angle and length of the intraosseous trajectory were significantly lower in the female than the male population (p<0.05). None of the virtual trajectories traversed the hip joint. In 112/120 trajectories (93.3%), there were no cortical breaches in the iliac bones. In eight trajectories in four patients, the virtual trajectory crossed either the medial iliac cortex (4/120; 3.3%) or the medial iliac cortex and the iliacus muscle (4/120; 3.3%)., Conclusion: The anterosuperior iliac and ischial spines can be used safely and reliably as landmarks to perform the double oblique anterior approach., (Copyright © 2020 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

Percutaneous image-guided oncologic interventions have rapidly evolved over the last two decades as an independent strategy or used within a first-, second-, or even third-line strategy in the treatment of musculoskeletal (MSK) tumors. Abundant mostly nonrandomized publications have described the safety, efficacy, and reproducibility of implementing percutaneous therapies both with curative and palliative intent. In this article, we continue to share our experience in bone and MSK soft tissue interventions focusing on stabilization and combined ablation and stabilization. We propose a pathway and explore future directions of image-guided interventional oncology related to skeletal disease. We reflect on the advantages and limitations of each technique and offer guidance and pearls to improve outcomes. Representing patterns from our practices, we demonstrate the role of collaborative working within a multidisciplinary team, ideally within a dedicated tumor treatment center, to deliver patient-specific therapy plans that are value based and favored by patients when given the choice., Competing Interests: None declared., (Thieme. All rights reserved.)

Objectives: To assess awareness and knowledge of Interventional Radiology (IR) in a large population of medical students in 2019., Methods: An anonymous survey was distributed electronically to 9546 medical students from first to sixth year at three European medical schools. The survey contained 14 questions, including two general questions on diagnostic radiology (DR) and artificial intelligence (AI), and 11 on IR. Responses were analyzed for all students and compared between preclinical (PCs) (first to third year) and clinical phase (Cs) (fourth to sixth year) of medical school. Of 9546 students, 1459 students (15.3%) answered the survey., Results: On DR questions, 34.8% answered that AI is a threat for radiologists (PCs: 246/725 (33.9%); Cs: 248/734 (36%)) and 91.1% thought that radiology has a future (PCs: 668/725 (92.1%); Cs: 657/734 (89.5%)). On IR questions, 80.8% (1179/1459) students had already heard of IR; 75.7% (1104/1459) stated that their knowledge of IR wasn't as good as the other specialties and 80% would like more lectures on IR. Finally, 24.2% (353/1459) indicated an interest in a career in IR with a majority of women in preclinical phase, but this trend reverses in clinical phase., Conclusions: Development of new technology supporting advances in artificial intelligence will likely continue to change the landscape of radiology; however, medical students remain confident in the need for specialty-trained human physicians in the future of radiology as a clinical practice. A large majority of medical students would like more information about IR in their medical curriculum; almost a quarter of students would be interested in a career in IR.

Management of musculoskeletal (MSK) tumours has traditionally been delivered by surgeons and medical oncologists. However, in recent years, image-guided interventional oncology (IO) has significantly impacted the clinical management of MSK tumours. With the rapid evolution of relevant technologies and the expanding range of clinical indications, it is likely that the impact of IO will significantly grow and further evolve in the near future.In this narrative review, we describe well-established and new interventional technologies that are currently integrating into the IO armamentarium available to radiologists to treat MSK tumours and illustrate new emerging IO indications for treatment.

The osseous pelvis is a frequent site of metastases. Alteration of bone integrity may lead to pain but also to functional disability and pathological fractures. Percutaneous image-guided minimally invasive procedures, such as cementoplasty and screw fixation, have emerged as a viable option to provide bone reinforcement and fracture fixation, as stand-alone or combined techniques. Understanding the biomechanics of the osseous pelvis is paramount to tailor the treatment to the clinical situation. The purpose of the present review is to present the biomechanics of the osseous pelvis and discuss its implication for the choice of the optimal consolidative treatment.

In the last few decades, thermal ablation (TA) techniques have been increasingly applied to treat small localised renal cell carcinomas. Despite this trend, there is still an underuse of TA compared to surgery and a substantial lack of high-quality evidence derived from large, prospective, randomised controlled trials comparing the long-term oncologic outcomes of TA and surgery. Therefore, in this narrative review, we assess published guidelines and recent literature concerning the diagnosis and management of kidney-confined renal cell carcinoma to understand whether percutaneous image-guided TA is ready to be proposed as a first-line treatment.

Objectives: To report managing renal tumors in patients at greater risk of repeated interventions (genetic predisposition, multifocal tumors) with thermoablative treatments (AT). A known significant challenge in these patients is the balance between nephron preservation and oncologic outcome., Material and Methods: This retrospective, single-center study was based on data from patients treated with one or more AT for hereditary or multifocal renal tumors between 2007 and 2017. All medical records were systematically reviewed, and 10 patients meeting inclusion criteria were selected. Six patients had confirmed von Hippel-Lindau disease, 1 Bird-Hogg-Dubé syndrome, 1 chromosome 3 translocation, and 2 had a presumed genetic predisposition., Results: Median age at cancer diagnosis was 39.5 years (±8.9). Fifty-seven tumors, including 41 de novo tumors that appeared during follow-up, were treated with 32 AT sessions (cryotherapy or radiofrequency) with an average tumor size of 13.5 mm (±9) and a median RENAL score of 6 [5; 7]. One patient underwent concomitant partial nephrectomy for a 55 mm lesion which was close to the bowel. Treatment was unsuccessful in 2 cases, subsequently managed successfully by retreatment with AT. Median delay of appearance of de novo tumor after the first AT was 18 months [6 ; 24]. One patient had metastatic progression. Overall and cancer specific survival was 90% and 100%, respectively, with a mean follow-up of 7.5 years (±4.9). The mean decrease in Chronic Kidney Disease - Epidemiological Collaboration equation-estimated glomerular filtration rate at the end of follow-up was 5.5 ml/min/1.73 m 2 (±24)., Conclusion: This study suggests that AT allows to meet the oncological objectives whilst preserving renal function in patients with renal cancer at greater risk of repeated treatments., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: To report the technique of hydrodissection of the sub-diaphragmatic bare area of the liver, in order to protect the diaphragm/heart during percutaneous thermal ablation (PTA) of sub-cardiac hepatic tumours., Materials and Methods: Between January 2016 and December 2018, five patients (four female, one male; mean age 56.2 years) with five sub-cardiac liver tumours (two hepatocellular carcinoma, three metastases; mean size 39 mm) abutting the bare area (segments II/IVA) with expected ablation zones ≤ 5 mm from the myocardium were treated with PTA and adjunctive hydrodissection. Time to perform hydrodissection, distance between superior hepatic and diaphragmatic/pericardial surfaces before and after hydrodissection, ablation efficacy, complications, and local tumour progression (LTP) at last imaging follow-up were recorded., Results: Technical feasibility was 100%, with mean hydrodissection-volume of 126 ml (range 80-200 ml) and median hydrodissection-time of 9 min (range 8-45 min). Liver-diaphragmatic and liver-pericardial distance increased, respectively, from 2.4 mm (range 0-8 mm) to 10.8 mm (range 6-19 mm) and from 4 mm (range 1-10 mm) to 12.6 mm (range 8-20 mm) post-hydrodissection. All procedures were performed at full-power with complete tumour ablation and without complications (including peri-procedural haemodynamic/electrocardiographic disturbances, pericardial effusion and diaphragmatic hernia) or evidence of LTP at mean 12.2-month (range 1-26 month) follow-up., Conclusion: Hydrodissection of the sub-diaphragmatic bare area of the liver is technically feasible and may potentially optimize safety PTA of sub-cardiac hepatic tumours.

Aim: To assess the clinical success rate of percutaneous radiofrequency and laser ablation of osteoid osteomas in older adults., Materials and Methods: Percutaneous radiofrequency or laser ablation was performed in 43 patients (35 years and older) with osteoid osteoma to achieve definitive cure in this retrospective study. The clinical success rate was defined as complete pain relief determined by numeric rating scale (NRS) scores (pre-procedural and post-procedural at 1-week, 6-week, and 2-year intervals). Tumour characteristics, technical success, procedural details, biopsy results, and complications were documented., Results: Forty-four osteoid osteomas were ablated in 43 patients, and all procedures were technically successful. The clinical success rates were 95.2% (41/43), 93% (40/43), and 93.2% (41/44) at 1-week, 6-week, and 2-year post-procedural intervals. The acute complication rate was 2.3% (1/44; meningeal perforation following epidural anaesthesia). No delayed complication was documented., Conclusion: Osteoid osteomas are not unique to the paediatric and young population, and safe and effective definitive treatment of these benign tumours in older adults can be achieved by percutaneous radiofrequency and laser ablation with excellent patient outcomes., (Copyright © 2020 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

Purpose: To report the retro-sternal space hydrodissection technique used to displace the heart and the pericardium posteriorly for thermoprotection ahead of sternal cryoablation (CA)., Methods and Materials: Between May 2015 and March 2020, hydrodissection of the retro-sternal space was performed in 5 consecutive patients (5 female; mean age 55.2 ± 9.3 years, range 41-65) who underwent percutaneous image-guided cryoablation of the sternum. The number of needles required, the implemented approach, volume of injectate to achieve hydrodissection, hydrodissection procedure time, distance between the lesion and the pericardium before and after hydrodissection, distance between the ice-ball and the pericardium, technical success and complications were retrospectively assessed., Results: Technical success, defined as the completion of a full dual freeze protocol without contact between the ice-ball and the pericardium, was achieved in all cases (5/5, 100%). One to two needles were used to perform hydrodissection via a perpendicular (3/5) or an anterior oblique approach (2/5) and a mean hydrodissection procedure time of 10.4 ± 2.6 min (range 8-14). Minimum distance between the lesion and the pericardium increased from mean 5.8 ± 3.8 mm (range 0-10) before hydrodissection to a mean 22.2 ± 5.8 mm (range 18-32) after, with a mean distance between the final ice-ball and the pericardium of 11.6 ± 8.7 mm (range 7-27). A mean of 198 ± 79.8 mL (range 90-290) of iodinated contrast was injected. There were no immediate, short- or medium-term complication noted., Conclusion: Hydrodissection of the retro-sternal space is a feasible technique for sternal cryoablation in order to protect the pericardium from freezing for sternal cryoablation.

Background Percutaneous radiofrequency ablation (RFA) is effective in the management of bone tumors. However, knowledge of the complication rate and risk factors for complications of RFA is lacking. Purpose To report the complication rate and risk factors of bone tumor RFA. Materials and Methods This retrospective study reviewed complications in consecutive patients who underwent RFA of primary or metastatic bone tumors from January 2008 to April 2018. Complications were categorized into major (grade 3 or 4, severe or life-threatening) or minor (grade 1 or 2, mild or moderate) according to Common Terminology Criteria for Adverse Events. Univariable and multivariable regression analyses were performed to identify variables associated with complications of RFA. Results A total of 169 patients (median age, 63 years; interquartile range, 55-73 years; 85 men) with 217 tumors were evaluated. The total complication rate was 30.0% (65 of 217; 95% confidence interval [CI]: 23.8%, 36.0%). The major complication rate was 2.3% (five of 217; 95% CI: 0.8%, 5.3%), with secondary fracture being the most frequent event (1.8% [four of 217]). The minor complication rate was 27.7% (60 of 217; 95% CI: 21.7%, 33.6%), with immediate postoperative pain being the most frequent event (18.0% [39 of 217]). Risk factors for all complications included tumor size greater than 3 cm (adjusted odds ratio [AOR], 2.4 [95% CI: 1.2, 4.5]; P = .03) and previous radiation therapy (AOR, 3.8 [95% CI: 2.0, 7.4]; P = .02). The only risk factor for minor complications was previous radiation therapy (AOR, 2.2 [95% CI: 1.0, 4.7]; P = .04). Conclusion Bone tumor radiofrequency ablation is safe, with a low rate of major complications mainly consistent with secondary fractures. Risk factors for complications are tumor size greater than 3 cm and previous radiation therapy. © RSNA, 2020 Online supplemental material is available for this article.

Purpose: To assess technical feasibility, accuracy, safety and patient radiation exposure of a novel navigational tool integrating augmented reality (AR) and artificial intelligence (AI), during percutaneous vertebroplasty of patients with vertebral compression fractures (VCFs)., Material and Methods: This prospective parallel randomised open trial compared the trans-pedicular access phase of percutaneous vertebroplasty across two groups of 10 patients, electronically randomised, with symptomatic single-level VCFs. Trocar insertion was performed using AR/AI-guidance with motion compensation in Group A, and standard fluoroscopy in Group B. The primary endpoint was technical feasibility in Group A. Secondary outcomes included the comparison of Groups A and B in terms of accuracy of trocar placement (distance between planned/actual trajectory on sagittal/coronal fluoroscopic images); complications; time for trocar deployment; and radiation dose/fluoroscopy time., Results: Technical feasibility in Group A was 100%. Accuracy in Group A was 1.68 ± 0.25 mm (skin entry point), and 1.02 ± 0.26 mm (trocar tip) in the sagittal plane, and 1.88 ± 0.28 mm (skin entry point) and 0.86 ± 0.17 mm (trocar tip) in the coronal plane, without any significant difference compared to Group B (p > 0.05). No complications were observed in the entire population. Time for trocar deployment was significantly longer in Group A (642 ± 210 s) than in Group B (336 ± 60 s; p = 0.001). Dose-area product and fluoroscopy time were significantly lower in Group A (182.6 ± 106.7 mGy cm 2 and 5.2 ± 2.6 s) than in Group B (367.8 ± 184.7 mGy cm 2 and 10.4 ± 4.1 s; p = 0.025 and 0.005), respectively., Conclusion: AR/AI-guided percutaneous vertebroplasty appears feasible, accurate and safe, and facilitates lower patient radiation exposure compared to standard fluoroscopic guidance. These slides can be retrieved under Electronic Supplementary Material.

Purpose: To retrospectively assess the technical feasibility, safety and clinical efficacy of percutaneous MR-guided cryoablation of low-flow vascular malformations (LFVM)., Materials and Methods: Between July 2013 and May 2019, 9 consecutive patients (5 male; 4 female; mean age 39.4 ± 15.3 years, range 15-68) underwent MR-guided cryoablation of LFVM. Patients were treated due to pain in all cases. Procedural data, complications and clinical results were analyzed., Results: Technical success defined as complete coverage of the LFVM by the iceball without involvement of nearby non-target thermal-sensitive structures was achieved in 9/9 (100%) cases. Mean procedure time was 122 ± 20 min (range 90-150); 2-6 cryoprobes (mean 3.7 ± 1.2) and 2-4 freezing cycles (mean freezing time 19.8 ± 11.8 min; range 4-40) were applied. No complications were noted. Mean time from the first treatment to the last follow-up was 548 days (range 30-1776). Persistent/recurring pain was noted in 3/9 cases (33%) 30, 133 and 639 days after cryoablation, respectively, and was related in all cases to MR-confirmed local residual/recurring disease. A second cryoablation treatment was performed in these 3 cases with complete pain control at the last available follow-up (153, 25, 91 days, respectively). In the whole population, at mean 161 days (range 25-413) after the last treatment, on the numerical pain rate scale, pain significantly dropped from mean 6.4 ± 2.1 (range 3-9/10) before CA to mean 0.3 ± 0.9 (range 0-3/10) after (p = 0.009)., Conclusions: Percutaneous MR-guided cryoablation is technically feasible, safe and effective for the treatment of symptomatic LFVM., Level of Evidence: Level 3b, retrospective cohort study.

Several interventional treatments have recently been integrated into the therapeutic armamentarium available for the treatment of bone tumors. In some scenarios (e.g., osteoid osteoma), interventional treatments represent the sole and definitive applied treatment. Due to the absence of widely shared protocols and the complex multivariate scenarios underlying the clinical presentation of the remaining bone tumors including metastases, therapeutic strategies derived from a multidisciplinary tumor board are essential to provide effective treatments tailored to each patient. In the present review, we present the multidisciplinary therapeutic strategies commonly adopted for the most frequent bone tumors., Competing Interests: None declared., (Thieme. All rights reserved.)

Purpose: To ascertain the performance of a new blunt-tip needle (HydroGuard ® ), which allows injection of fluids during needle advancement in order to safely approach, displace and insulate nearby critical structures during thermal ablation (TA)., Materials and Methods: This study included 27 consecutive patients treated by TA [cryoablation (CA), radiofrequency (RFA), and microwave MWA)] between April 2018 and January 2019. During TA, hydro- or gas dissection was performed with HydroGuard ® needle to displace and protect critical structures close to the tumor (< 10 mm). Technical and clinical success, distance between critical structure and tumor before and after hydro/gas dissection and complications were recorded., Results: Eighteen patients were treated by CA (66.7%), 7 by MWA (25.9%) and 2 by RFA (7.4%). Majority of patients were treated with a curative intent (24/27; 88.8%). Adjacent critical structures include vessels (n = 3), nerves (n = 10), ureter/renal pelvis (n = 3), bowel/rectum (n = 10), stomach: (n = 3), diaphragm (n = 2), and pleura (n = 1). Technical success was 100%. Clinical success was 88% (24/27). Median minimum distance to adjacent critical structures before hydro/gas dissection was 1 mm (range 0-9 mm; IQR: 0-3 mm) versus 10.5 mm (range 4-47 mm; IQR: 9.7-18 mm) after displacement. Of the 27 patients treated, four developed complications (14.8%; 95% CI: 1.4-28.2): 1 major (3.7%; 95% CI: 0-10.8) and 3 minors (11.1%; 95% CI: 0-23). Only one minor complication was related to inadequate hydro-dissection, resulting in close proximity of the critical structure to the ablation zone., Conclusion: HydroGuard ® is a safe and effective needle when used to approach, displace and insulate nearby critical structures during TA.

Percutaneous thermal ablation has proven to be safe and effective in the management of patients with spinal tumors. Such treatment is currently proposed following the decision of a multidisciplinary tumor board to patients with small painful benign tumors such as osteoid osteoma or osteoblastoma, as well as carefully selected patients presenting with spinal metastases. In both scenarios, in order to provide a clinically effective procedure, ablation is often tailored to the specific patients' clinical needs and features of the target tumor. In this review, we present the most common clinical contexts in which spine ablation may be proposed. We scrutinize technical aspects and challenges that may be encountered during the procedure, as well as offering insight on follow-up and expected outcomes., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: The aim of this retrospective study is to represent our experience in percutaneous MRI-guided prostate procedures (biopsy and cryotherapy), and to discuss the improvement achieved in standardization of these procedures leading to a gain in feasibility and reproducibility of the technique used by urologists while handling MRI-environment., Methods: From 2009 to 2018, 62 patients required MRI-guided prostate procedures in our institute. Throughout 9 years of experience, we have achieved an improvement of the technique used to protect the rectum and the urethra which increased accuracy and reproducibility. Procedures were performed by both urologists and radiologists under MRI guidance (Magnetom-Espree and Magnetom-Aera; Siemens, Erlangen, Germany) in a dedicated hybrid-room., Results: Utilization of a patient stand and an acrylic needle-guided template created by Noras Company allowed standardization of the technique used and thus allowed an increase in accuracy. In order to protect the rectum, we inject patient's own blood into the Denonvillier's fascia which helps to dissect away the prostate from the rectum. In addition, the use of a thermocouple assistance probe placed in the urethral sphincter enabled urethral temperature monitoring during the entire procedure. The aim of temperature monitoring is to protect the urethra from possible thermal injuries., Conclusions: Improvements achieved in our technique used in MRI guided prostate procedures may allow wide spread use of this technique in both radiological and urological fields and opens opportunities in the development of focal therapy of the prostate using MRI-guidance., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at http://dx.doi.org/10.21037/tcr.2020.03.44). The authors have no conflicts of interest to declare., (2020 Translational Cancer Research. All rights reserved.)

Purpose: To study the interobserver agreement for the analysis of lesion filling following cementoplasty of an acetabular osteolytic lesion, and investigate how subjective analysis compares to volumetric analysis., Materials and Methods: A total of 21 acetabular osteolysis were retrospectively analysed on pre- and immediate post-cementoplasty CT-scans by two senior interventional radiologists and one resident using a 4 grade scale to quantify lesion filling (F subjective ): F ≤ 25%, 25% < F ≤ 50%, 50% < F ≤ 75% or F > 75%. Volumetric analysis (F volumetric ) was performed with the delineation of the osteolysis and the cement using regions of interest. The interobserver agreement for F subjective was evaluated using the Fleiss' Kappa test for the 4 grade scale and for a simplified 2 grades scale (F ≤ 50% and F > 50%). The performance of F subjective versus F volumetric (considered as the gold standard) was then evaluated for each reader using the calculation of accuracy and error to reference for the 4 grades scale and accuracy, sensitivity, specificity, positive predictive value and negative predictive value for the 2 grade scale., Results: Interobserver agreement was considered as very low (< 0.2) for the 4 grade scale analysis and as low (> 0.2 and < 0.4) for the 2 grade scales analysis with kappa factors of 0.196 and 0.36 respectively. Compared to volumetric analysis, the overall accuracy of the 4- and 2- grade scales were 36.5% and 60% respectively., Conclusion: Subjective evaluation of cement filling of an acetabular osteolytic lesion is associated with poor interobserver agreement and overestimation of the percentage compared to volumetric analysis.

Aim: To investigate the shape and the volume of ablation zones obtained with microwave ablation (MWA) performed with multiple antennas in liver tumours., Materials and Methods: Tumour volume, number of antennas, size (long diameter (Dl), along the antenna axis; short diameter (Ds), perpendicular to the antenna axis; vertical diameter (Dv), vertical to both Dl and Ds) and shape (roundness index (RI); 1 corresponds to a sphere) of the ablation zone, ablation volume, and complications were evaluated., Results: Mean Dl, Ds, and Dv were 4.7 ± 1.4 cm, 3.9 ± 1.4 cm, and 3.8 ± 1.0 cm, respectively. Mean RIs (Ds/Dl, Dv/Dl, and Dv/Ds) were 0.83 ± 0.13, 0.83 ± 0.17, and 1.02 ± 0.23, respectively, without any difference between the mean RI obtained with the double (0.84 ± 0.01) and that with the triple-antenna (0.93 ± 0.13) approach (p = 0.25). Mean ablation volume was 41 ± 32 cm 3 (vs. mean tumour volume 13 ± 10 cm 3 ; range 1-40; p < 0.001). No complications were noted., Conclusions: Simultaneous multi-antenna MWA of liver tumours results in large nearly spherical ablation zones., Key Points: • Simultaneous multi-antenna microwave ablation of liver tumours results in nearly spherical ablation zones. • The multi-antenna approach generates oversized ablation volumes compared with the target tumour volume. • The multi-antenna approach is safe.

Objective: To determine the pejorative predictive factors on oncologic outcomes of percutaneous MR-guided whole gland prostate cancer cryoablation (CA)., Methods: Medical records of patients treated from 2009 to 2012, to assess medium-term oncologic outcomes, were reviewed. Prostate biopsies were performed in local recurrence suspicion (biochemical failure, MR follow-up failure)., Results: Among 18 patients, mean age of 72.6 (61-78), 2 (11 %) and 7 (38.9 %) biological and reported biopsy-proven local recurrence respectively with our initial technic of CA. Mean follow-up and recurrence were 56.3 (±21.7) and 20.7 (±13.9) months respectively. A previous treatment of prostate cancer (P=0.5), pre-treatment PSA (P=0.2), pre-treatment Gleason/ISUP score (P=0.4), nadir PSA post-CA (P=0.22) were not associated with recurrence. Bilateral positive cores appears as a pejorative predictive factor (P=0.04). However mean pre-treatment positive cores percentage, 25 (±16.5) in responding patients versus 40.7 (±25.2) in case of recurrence, and maximum percentage of cancer extent in each positive core, 10.6 (±9.3) in responding patients versus 18.7 (±16.5) in case of recurrence, seemed associated with local recurrence after prostate CA but our analysis wasn't able to find a difference (P=0.09 and P=0.3 respectively) due to a lack of power., Conclusion: Bilateral positive cores appears as a pejorative predictive factor. In our experience, important tumor volume seem to be a pejorative predictive factor for oncologic outcomes after PCA whereas treatment, PSA, Gleason/ISUP score, nadir PSA are not., Level of Evidence: 4., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

Objectives: To retrospectively compare the safety profile of percutaneous image-guided radiofrequency ablation (RFA) and cryoablation (CA) of bone metastases (BM) with and without a propensity score analysis., Methods: Between January 2008 and April 2018, 274 consecutive patients (mean age 61.6 ± 12.1 years) with BM were treated at our Institution with RFA (53 patients; 66 BM) or CA (221 patients; 301 BM) and included in this study. Complications were assessed according to the type of ablation modality before and after applying a 1:1 propensity score method taking into account patient's demographics, BM features, procedural details and follow-up findings., Results: In the whole 9 BM (2.5%) reported major complications without significant difference between RFA (1/66; 1.5%) and CA (8/301; 2.7%; p  = 1); 40 BM (10.9%) showed minor complications, which were more common with RFA (22/66; 33.3%) than with CA (18/301; 6.0%, p <.001) mainly due to post-procedural pain occurring more frequently with RFA than CA (20/66; 30.3% vs. 7/301; 2.3%, p <.001). Following 1:1 matching, similar results were obtained, since there were similar rates of major complications with RFA and CA (1/66 [1.5%] and 0/66 [0.0%], respectively; p  = 1); and higher rates of minor complications with RFA compared to CA [33.3% (22/66) vs. 2/66 (3%); p <.001] due to preponderant postprocedural pain (90.9% [20/22] minor complications with RFA)., Conclusions: Similar low rates of major complications are expected with RFA and CA of BM. In the post-operative period, RFA appears more painful than CA, thus warranting for adoption of dedicated analgesic protocols for patients undergoing RFA.

Purpose: To test in vivo in an animal model the inherent atraumatic characteristics of the spring loaded blunt tip of a coaxial needle (Gangi-SoftGuard®, Apriomed, Sweden) against a conventional sharp stylet coaxial needle., Material and Methods: The study was conducted on a 40kg male swine that was its own control for a vascular trauma model. The procedure consisted of voluntary attempts to transfix and traverse the artery/aorta under continuous real-time angiogram. Test and control needles were positioned in the region of the intercostal, superior mesenteric and femoral/deep femoral arteries, and in the aorta. Computed tomography (CT) angiogram was performed post trauma to check for bleeding in the form of extravasation of contrast material. One attempt was performed per site and needle, except for the intercostal artery where a second attempt was done with the test needle, resulting in a total of 4 and 5 tests for the control and test needles, respectively., Results: With the spring loaded blunt tip, no vascular trauma or bleeding was noted in the intercostal, superior mesenteric and femoral arteries, nor in the aorta. Vascular spasm that recovered with time was noted during the second attempt to transfix the same intercostal artery. There were consistent vascular traumas and bleedings with the control needle in all three tested arteries and the aorta, confirmed on angiogram as well as CT angiogram., Conclusion: The atraumatic feature offered by the spring loaded blunt tip prevented vascular trauma during the 5 attempts made to transfix the artery/aorta in a swine., (Copyright © 2019 Société française de radiologie. Published by Elsevier Masson SAS. All rights reserved.)

Purpose: To perform a systematic review of technical details and clinical outcomes of percutaneous extra-spinal cementoplasty in patients with malignant lesions., Materials and Methods: PUBMED, MEDLINE, MEDLINE in-process, EMBASE and the Cochrane databases were searched between January 1990 and February 2019 using the keywords «percutaneous cementoplasty», «percutaneous osteoplasty» and «extra-spinal cementoplasty». Inclusion criteria were: retrospective/prospective cohort with more than 4 patients, published in English language, reporting the use of percutaneous injection of cement inside an extra-spinal bone malignant tumour using a dedicated bone trocar, as a stand-alone procedure or in combination with another percutaneous intervention, in order to provide pain palliation and/or bone consolidation., Results: Thirty articles involving 652 patients with a total of 761 lesions were reviewed. Mean size of lesion was 45mm (range of mean size among publications: 29-73mm); 489 lesions were located in the pelvis, 262 in the long bones of the limbs and 10 in other locations. Cementoplasty was reported as a stand-alone procedure for 60.1% of lesions, and combined with thermal ablation for 26.2% of lesions, implant devices for 12.3% of lesions, and balloon kyphoplasty for 1.4% of lesions. The mean volume of injected cement was 8.8mL (range of mean volume among publications: 2.7-32.2mL). The preoperative visual analogic scores ranged between 3.2 and 9.5. Postoperative scores at last available follow-up ranged from 0.4 to 5.6. Thirteen papers reported a reduction of the visual analogic scores of 5 points or more. Nerve injury was the most frequent symptomatic leakage (0.6%)., Conclusion: Percutaneous extra-spinal cementopasty is predominantly performed as a stand-alone procedure and for lesions in the bony pelvis. It appears to be an effective tool to manage pain associated with malignant bone tumours. There is however a lack of standardization of the technique among the different publications., (Copyright © 2019 Société française de radiologie. Published by Elsevier Masson SAS. All rights reserved.)

Introduction: To evaluate the effectiveness of percutaneous image-guided vertebral body stenting (VBS) at restoring vertebral height in acute, stable, traumatic thoracolumbar fractures in a young, non-osteoporotic population., Materials and Methods: A single-centre retrospective review of all traumatic non-osteoporotic fractures treated with VBS between 2010 and 2017 was performed. Inclusion criteria included patients with recent (< 10 days), symptomatic and stable thoracolumbar compression fractures. Patients with low-energy fractures, osteoporosis and age > 60/50 years (male/female) were excluded. Primary outcomes included: correction of vertebral height, correction of kyphosis angle and Beck Index on reconstructed pre- and post-procedural CBCT images. Secondary outcomes included intra-procedural stent recoil, complications, cement leakage and factors predicting height restoration., Results: Thirty-nine patients (26 men, 13 women; mean age 33.6 years, range 15-57 years) underwent VBS 5 days post-trauma on average (range 1-10), for stable compression fractures located between T5 and L5. Mean vertebral height gain, vertebral kyphosis angle correction and Beck index improvement were 3.8 mm (95% CI 3.36-4.50; P(> 3 mm) = 99.9%), 4.3° (95% CI 3.50-5.20; P(> 3°) = 99.9%) and 0.07 [95% CI 0.053-0.11], respectively (all statistically significant). Technical success was 92%, with 3 "major" stent recoils resulting in loss of vertebral height correction. No symptomatic complications were observed. No predictive factors for procedural success were identified., Conclusion: VBS can significantly restore vertebral height in young patients with traumatic vertebral compression fractures.

Imaging-guided interventional procedures have become increasingly popular in the treatment of several pathologic conditions in the musculoskeletal system. Besides oncological treatments, musculoskeletal procedures can be performed to treat different degenerative or inflammatory conditions. This paper is aimed to review clinical indications and technical aspects of these kinds of procedures. In particular, we revise the general aspects common to most procedures and the different imaging-guided interventions which can be performed around joints, soft tissues, and spine.

Objective: To investigate the safety profile of percutaneous cryoablation of renal tumours < 7 cm, utilising data extracted from an international multicentre registry., Materials and Methods: A retrospective review of all immediate and delayed complications from a multicentre database was performed and was categorised according to the Clavien-Dindo classification. Statistical analysis was performed for both overall complications (all Clavien-Dindo) and major complications (Clavien-Dindo 3 to 5). The following criteria were identified as potential predictive factors for complications: centre number, modality of image guidance, tumour size (≤ 4 cm vs. > 4 cm), number of tumours treated in the same session (1 vs. > 1) and tumour histology., Results: A total of 713 renal tumours underwent ablation in 647 individual sessions. In 596 of the cases, one tumour was treated; in the remaining 51 cases, several tumours were treated per session. Mean lesion size was 2.8 cm. Fifty-four complications (Clavien-Dindo 1 to 5) occurred as a result of the 647 procedures, corresponding to an overall complication rate of 8.3%. The most frequent complication was bleeding (3.2%), with 9 cases (1.4%) requiring subsequent treatment. The rate of major complication was 3.4%. The only statistically significant prognostic factor for a major complication was a tumour size > 4 cm., Conclusion: Percutaneous renal cryoablation is associated with a low rate of complications. Tumours measuring more than 4 cm are associated with a higher risk of major complications., Key Points: • Percutaneous kidney cryoablation has a low rate of complications. • Bleeding is the most frequent complication. • A tumour size superior to 4 cm is a predictive factor of major complication.

OBJECTIVE. The aim of this observational study was to assess safety and clinical outcomes of percutaneous image-guided cryoablation (CA) to treat osteoblastomas (OBs) at various osseous sites. MATERIALS AND METHODS. A retrospective search was performed to identify patients presenting with painful OBs who underwent CA at the University Hospitals of Strasbourg between March 2007 and December 2018. Ten patients (seven men, three women; median age, 21 years old) were identified and included. Medical records were reviewed to assess complications and clinical outcomes. RESULTS. Median OB diameter was 16.5 mm (range, 16-28 mm). OBs were located in the spine ( n = 7), calcaneus ( n = 1), fibula ( n = 1), and third metacarpal bone ( n = 1). In 90% of cases ( n = 9), one or more critical structures were within 1 cm of the OB (median distance, 5 mm; range, 2-8 mm), thus requiring extensive protective measures. Technical success was achieved in all cases. Two (20%) immediate neural complications were noted. One major complication was consistent with a permanent sensory deficit of the arm. One minor complication was consistent with a transient right Horner syndrome, which completely resolved after 48 hours with high-dose steroids. Median clinical follow-up was 12 months. Primary clinical success was 100% and 78% at 1 and 12 months of follow-up, respectively, with two patients presenting with recurring pain. CONCLUSION. Percutaneous image-guided CA represents an effective therapeutic option for patients affected by painful OBs; the safety profile of the procedure is acceptable as long as comprehensive protective measures are deployed in light of the frequent close proximity of critical structures.