MR-Guided Transurethral Ultrasound Ablation (TULSA)-An Emerging Minimally Invasive Treatment Option for Localised Prostate Cancer.

The optimal treatment strategy for men with localised prostatic cancer of low and intermediate risk is an actively evolving field. It is important to strike a balance between maximal oncological control and minimal treatment-related complications, which helps preserve the patients' quality of life. MR-guided transurethral ultrasound ablation (TULSA) has emerged as a minimally invasive treatment option for this group of patients. This article aims to provide of a background on TULSA technology, a step-by-step procedural guide of MR-guided TULSA and to summarise the current evidence of TULSA in management of localised prostatic cancer, as well as other potential indications.

Focal Myositis of the Sternocleidomastoid Muscle: A Rare and Uncommon Cause of Cervical Mass.

We report on a 70-year-old male patient admitted to the internal medicine department for evaluation of a right cervical mass. He had been treated with antibiotics as an outpatient by his primary care doctor. Upon admission the patient was asymptomatic, but within a few hours his cervical mass enlarged; this enlargement was confined to the right sternocleidomastoid muscle. Complete blood investigations including serology and autoimmunity were negative. The neck scan and MRI were in favour of myositis. No other lesions were found either in the nasal fibre-optic exam or in the thoracic-abdominal-pelvic scan. The biopsy of the muscle showed a lymphoplasmacytic inflammatory infiltrate of the perimysium. The diagnosis of focal myositis was made. The patient clinically improved during hospitalisation with complete resolution of symptoms without any specific intervention. LEARNING POINTS: A thorough clinical examination is essential in the evaluation and characterisation of cervical masses.The diagnostic approach must be rigorous in order not to ignore potentially serious diseases.A high level of clinical suspicion is needed in the diagnosis of focal myositis.

MRI- Versus CT-Guided Renal Tumor Cryoablation: Is There a Difference?

PURPOSE: To compare procedure-related variables, safety, renal function, and oncologic outcomes in patients undergoing percutaneous cryoablation (CA) of renal tumors with MRI- or CT-guidance. MATERIALS AND METHODS: Patient, tumour, procedure, and follow-up data were collected and analysed. MRI and CT groups were matched using a coarsened exact approach according to patient's gender and age, tumour grade, size and location. P < 0.05 was considered statistically significant. RESULTS: Two-hundred fifty-three patients (266 tumors) were retrospectively selected. Following the coarsened exact matching 46 patients (46 tumors) in the MRI group and 42 patients (42 tumors) in the CT group were matched. There were no significant baseline differences between the two populations except for the duration of follow-up (P = 0.002) and renal function (P = 0.002). On average MRI-guided CA lasted 21 min longer than CT-guided ones (P = 0.005). Following CA, complication rates (6.5% for MRI vs 14.3% for CT; P = 0.30) and GFR decline (mean - 13.1 ± 15.8%; range - 64.5-15.0 for MRI; mean - 8.1 ± 14.8%; range - 52.5-20.4; for CT; P = 0.13) were similar in both groups. The 5-year local progression-free, cancer-specific and overall survivals in the MRI and CT groups were 94.0% (95% CI 86.3%-100.0%) and 90.8% (95% CI 81.3%-100.0%; P = 0.55), 100.0% (95% CI 100.0%-100.0%) and 100.0% (95% CI 100.0%-100.0%; P = 1), and 83.7% (95% CI 64.0%-100.0%) and 76.2% (95% CI 62.0%-93.6%; P = 0.41), respectively. CONCLUSIONS: Apart from increased procedural times associated with MRI-guided CA of renal tumors compared to CT-guidance, both modalities demonstrate similar safety, GFR decline and oncologic outcomes.

Role of MRI at 1- and 3-Month Follow-up in Predicting the Likelihood of Tumor Recurrence Following Percutaneous Cryoablation of Renal Tumors.

PURPOSE: To evaluate whether ablation volume difference relatively to tumoral volume, minimal distance between ablation area and necrotic tumor, or apparent diffusion coefficient (ADC) within the ablation area, measured on 1- and 3-month follow-up MRI following cryoablation of renal tumors, are associated with tumor recurrence. MATERIALS AND METHODS: 136 renal tumors were retrospectively identified. Patients, tumor characteristics and follow-up MRI (1-, 3-, 6-month, and thereafter annually) were collected. Uni- and multivariate analyses were performed to assess the association between the investigated parameters and tumor recurrence. RESULTS: Over the follow-up period (27.7 ± 21.9 months), 13 recurrences were identified at 20.5 ± 19.4 months. At 1- and 3-month, the mean volume difference between the ablation zone and the tumor volume were + 577.5 ± 511.3% vs + 251.4 ± 209.8% (p = 0.003), and + 268.8 ± 291.1% vs + 103.8 ± 94.6% (p = 0.023) in patients without and with tumor recurrence, respectively. At 1- and 3-month, the minimum distance between the necrotic tumor and the edge of the ablation area was 3.4 ± 2.5 vs 1.8 ± 1.9 mm (p = 0.019), and 2.4 ± 2.3 vs 1.4 ± 1.8 mm (p = 0.13) in patients without and with tumor recurrence, respectively. Analysis of ADC values was not associated with tumor recurrence. After performing the multivariate analysis, only volume difference of the ablation area compared to tumor volume was associated with absence of tumor recurrence at 1- (OR = 14.1; p = 0.001) and 3-month (OR = 8.2; p = 0.01). CONCLUSIONS: Evaluation of volume difference between the ablation area and tumor volume on early (≤ 3 months) MRI follow-up identifies patients at risk of tumor recurrence.

Bone Consolidation: A Practical Guide for the Interventional Radiologist.

In recent years, interventional radiologists have been increasingly involved in the management of bone fractures resulting from benign (osteoporosis and trauma), as well as malignant (tumor-related impending or pathologic fractures) conditions. Interventional techniques used to fix fractures include image-guided osteoplasty, screw-mediated osteosynthesis, or combinations of both. In the present narrative review, we highlight the most common clinical scenarios that may benefit from such interventional techniques with specific focus on spine, pelvic ring, and long bones.

Percutaneous image-guided cryoablation with temporary balloon occlusion of the renal artery for the treatment of central renal tumors.

PURPOSE: The purpose of this study was to report the technical feasibility and outcomes of percutaneous image-guided cryoablation with temporary balloon occlusion of the renal artery for the treatment of central renal tumors. MATERIALS AND METHODS: All consecutive patients with central renal tumors treated with cryoablation and temporary renal artery occlusion from January 2017 to October 2021 were retrospectively included. Patient demographics, tumor's characteristics, procedural data, technical success, primary and secondary clinical efficacy, complications (according to Cardiovascular and Interventional Radiology Society of Europe [CIRSE] classification) and follow-up were investigated. RESULTS: A total of 14 patients (8 men, 6 women; mean age 72.4 years ± 21.4 [SD] years; age range: 42-93 years) with 14 central renal tumors (median size, 32 mm; IQR: 23.5, 39.5 mm; range: 13-50 mm) were treated with percutaneous image-guided cryoablation and temporary balloon occlusion of the renal artery. Technical success was 13/14 (93%), with 1/14 (7%) failure of vascular access. A median of 4 cryoprobes (IQR: 3, 4.75) were inserted and protective hydrodissection was performed in 11/14 (79%) patients. Median time to perform cryoprobes insertion, hydrodissection and vascular access was 26.5 min (IQR: 18, 35 min), 10 min (IQR: 10, 17 min) and 30 min (IQR: 20, 45 min) respectively. Median duration of the whole intervention was 150 min (IQR: 129, 180 min; range: 100-270 min). Median hospital stay was 2.5 days (IQR: 2, 4 days; range: 2-14 days). Major complications occurred in 3/14 (21%) patients. Primary efficacy rate was 93% (13/14 patients). Median oncological follow-up was 25 months (IQR: 11, 33 months; range: 6-39 months). One patient experienced renal tumor recurrence at 14-months of follow-up, which was successfully treated with repeat cryoablation. CONCLUSION: Percutaneous image-guided cryoablation of renal tumors with temporary balloon occlusion of the renal artery is technically feasible, with a high technical success rate and paths the way for percutaneous treatment of central renal tumors.

Safety and Oncologic Outcomes of Percutaneous Cryoablation of Renal Cell Carcinoma Recurrences in the Ipsilateral Kidney Following Partial Nephrectomy.

PURPOSE: To retrospectively investigate the safety and oncological outcomes of cryoablation performed on residual/recurring renal cell carcinoma (RCC) in the ipsilateral kidney following partial nephrectomy (PN). MATERIALS AND METHODS: Data dealing with patients', RCC, procedure (including the length of the hospital stay), and follow-up (technical efficacy [TE], local tumor progression-free survival [LTPFS], disease-free survival [DFS], metastasis-free survival [MFS], cancer-specific survival (CSS), and overall survival [OS]) were retrospectively collected and analyzed. RESULTS: Between January 2008 and November 2020, 21 consecutive patients (17 [81%] men; 4 [19%] women; median age 68 years; range 43-82) underwent cryoablation due to residual/recurring RCC in the PN site (15 patients) or de-novo RCC (6 patients) in the ipsilateral kidney. Median tumor size was 2.2 cm (mean 2.3 cm; range 0.8-4; interquartile range [IQR] 1.9-3). There were two (2/21; 10%) minor self-limiting hemorrhagic complications, both occurring in the group of patients with RCC in the PN site. Median hospital stay was 2 days (mean 2.1; range 1-5; IQR 2-2). TE was 100% (21/21 patients), and 10-year estimates of LTPFS, MFS and DFS were 74.1% (95% confidence intervals [CI] 56.8-96.7%), 36.4% (95% CI 14.2-93.8%), and 43.5% (95% CI 21.9-86.4%), respectively. CSS and OS were 100% at the last available follow-up (median 56 months; mean 67.4; range: 12-147; IQR:34-95). CONCLUSION: Cryoablation in patients with residual/recurring RCC following PN is safe and results in high 10-year estimates of LTPFS.

Percutaneous osteoplasty in long bones: Current status and assessment of outcomes.

Osteoplasty is a minimally invasive imaging-guided intervention providing mechanical stabilization, bone consolidation and pain relief in oncologic patients presenting with non-osteoblastic bone metastases or with insufficiency fractures. The intervention relies on the injection of an acrylic substance (ie, polymethylmethacrylate; PMMA) into the target bone. PMMA is very resistant to axial compressive loads but much less to bending, torsional and shearing stresses. Accordingly, from a biomechanical standpoint osteoplasty is adapted for the palliative treatment of small painful lytic bone defects located in the epiphyseal region of long bones in patients with clear surgical contraindications; or for increasing the anchoring of the osteosynthesis material into the target bone. Although pain relief is rapid and effective following osteoplasty, secondary fractures have been reported in up to 8-9% of long bone tumors undergoing such intervention; and following such event, fixation with endomedullary osteosynthetic material (eg, nailing) is not practicable any more. Accordingly, careful patients' selection is critical and should happen with a multidisciplinary approach.

Sporadic Desmoid Tumours: Systematic Review with Reflection on the Role of Cryoablation.

Desmoid tumours (DT) are rare locally infiltrative soft-tissue tumours which do not metastasise. DT arise sporadically or are associated with familial syndromes, with different clinical and genetic patterns. In recent years there has been an increasing therapeutic role of cryoablation for the treatment of sporadic DT. Therefore, in this present review, we: (a) summarize all the main epidemiological, clinical, and therapeutic aspects of sporadic DT that are relevant to an interventional radiologists' practice; (b) present the results of a systematic review that has been conducted with the intent of highlighting the main clinical outcomes available thus far with cryoablation; and (c) discuss the current and future potential applications of cryoablation in this field. Five studies were included in the systematic review accounting for 146 patients. Only 18.5% patients received cryoablation as a first-line treatment. Overall, the volume of the DT undergoing cryoablation was very large (mean total DT volume of 237 cm3). Major complications were noted for 13.3-30% patients and following 2.4-6.7% interventional sessions. The rates of complete tumour response ranged between 0 and 43.3%. 1- and 3-year local progression-free survival rates were 85.1-85.8%, and 77.3-82.9%, respectively. Complete pain relief was reported in 40-66.7% symptomatic patients. In conclusion, cryoablation is currently proposed as a therapeutic strategy to very large DT, which is recognized to be associated with an increased procedure-related morbidity and reduced rates of complete tumour response. Proposing cryoablation as the first-line treatment may improve these clinical outcomes.

Safety and Efficacy of Percutaneous Cryoablation of Extraspinal Thyroid Cancer Bone Metastases with Curative Intent: Single-Center Experience with a Median Follow-up of More than 5 Years.

PURPOSE: To determine the oncologic outcomes and safety profile of image-guided percutaneous cryoablation (PCA) for extraspinal thyroid cancer bone metastases with curative intent. MATERIALS AND METHODS: Between January 2010 and January 2020, 16 consecutive patients (8 men, 8 women; mean age, 61 years ± 19; range, 30-84 years) with 18 bone metastases (median bone tumor size, 19 mm; interquartile range [IQR], 12-29 mm; range, 7-58 mm) underwent PCA of oligometastatic extraspinal bone metastases. Thirteen (81%) patients were radioiodine therapy resistant. Two patients underwent 2 bone tumor ablations in a single session. Procedural data, oncologic outcomes, follow-up (with magnetic resonance imaging and positron emission tomography-computed tomography), and adverse events were retrospectively investigated. Local tumor progression-free survival, disease-free survival, and overall survival were estimated using the Kaplan-Meier method. RESULTS: A median of 2 cryoprobes (IQR, 1.25-3 cryoprobes; range, 1-7 cryoprobes) were used, with 2 freezing cycles; the median length of freezing was 20 minutes (IQR, 17-20 minutes; range, 10-20 minutes). The technical success was 100% (18/18), and the primary technical efficacy was 94.4% (17/18). The median follow-up was 68 months (IQR, 38-93 months). During follow-up, 3 of 17 (17.6%) tumors demonstrated local progression at 7, 13, and 27 months. Consequently, the 1-, 2-, 3-, 4-, and 5-year local tumor progression-free survivals were 93.3%, 84.6%, 76.9%, 75%, and 72.7%, respectively. Two of 16 (12.5%) patients died during follow-up at 43 and 88 months. The major adverse event rate was 5.5% (1/18) with 1 postablative acromion fracture. CONCLUSIONS: PCA for extraspinal thyroid cancer bone metastases demonstrated high local tumor control rates with a safe profile at long-term follow-up.

Percutaneous image-guided cryoablation of spinal metastases: over 10-year experience in two academic centers.

OBJECTIVES: To report on safety and clinical effectiveness of cryoablation for the treatment of spinal metastases (SM) in patients needing pain palliation or local tumor control (LTC). METHODS: All consecutive patients with SM who underwent cryoablation from May 2008 to September 2020 in two academic centers were retrospectively identified and included in the present analysis. Patient characteristics, goal of treatment (curative/palliative), SM characteristics, procedural details, and clinical outcomes (pain relief; local tumor control [LTC]) were analyzed. RESULTS: There were 74 patients (35 women; median age 61 years) accounting for 105 SM. Additional cementoplasty was used for 76 SM (76/105; 72.4%). There were 9 complications (out of 105 SM [8.5%]; 2 major and 7 minor) in 8 patients. Among the 64 (64/74; 86.5%) patients with painful SM, the mean Numerical Pain Rating Scale dropped from 6.8 ± 2.2 (range, 0-10) at the baseline to 4.1 ± 2.4 (range, 0-9; p < 0.0001) at 24 h, 2.5 ± 2.6 (range, 0-9; p < 0.0001) at 1 month, and 2.4 ± 2.5 (range, 0-9; p < 0.0001) at the last available follow-up (mean 14.7 ± 19.6 months; median 6). Thirty-four patients (34/64; 53.1%) were completely pain-free at the last follow-up. At mean 25.9 ± 21.2 months (median 16.5) of follow-up, LTC was achieved in 23/28 (82.1%) SM in 21 patients undergoing cryoablation with curative intent. CONCLUSION: Cryoablation of SM, often performed in combination with vertebral augmentation, is safe, achieves fast and sustained pain relief, and provides high rates of LTC at mean 2-year follow-up. KEY POINTS: •Cryoablation of spinal metastases is safe. •Cryoablation of spinal metastases allows rapid and sustained pain relief. •The mean 2-year rate of local tumor control after cryoablation of spinal metastases is 82.1%.

Freezing Nodal Disease: Local Control Following Percutaneous Image-Guided Cryoablation of Locoregional and Distant Lymph Node Oligometastases: A 10-Year, Single-Center Experience.

PURPOSE: To retrospectively assess the technical feasibility, safety, and oncologic outcomes of percutaneous image-guided cryoablation (PCA) of locoregional and distant lymph node metastases (LNMs). METHODS: All consecutive patients undergoing PCA of LNMs between February 2009 and December 2019 were identified using a retrospective database search. Every patient was followed up at 1, 3, 6, and 12 months after treatment using contrast-enhanced magnetic resonance imaging and at approximately 3-6-month intervals using computed tomography or positron emission tomography-computed tomography. The Kaplan-Meier method was used to calculate local tumor progression-free survival, disease-free survival, and overall survival. Locoregional and distant groups were compared using the Fisher test. Technical success, technique efficacy, complications, and oncologic outcomes were analyzed. RESULTS: Fifty-six metachronous oligometastatic LNMs (median size, 15 mm [interquartile range, 13-15 mm; range, 9-36 mm]) were treated in 37 sessions in 29 patients and defined as locoregional (26/37 sessions) or distant (11/37 sessions). Seventeen patients had undergone prior surgery or radiotherapy. Six patients underwent 8 retreatments for locoregional progression. An additional visceral oligometastasis was treated in 4 of the 11 distant LNM PCA sessions. The technical success and primary technique efficacy rates were 100%. The complication rate was 5.4% (2 transient nerve palsies). At a median follow-up of 23 months, there were 2 instances of local tumor progression (5.6%); the 1-, 2-, and 3-year local tumor progression-free survival was 100%, 94.3%, and 94.3%, respectively. Thirteen (45%) patients demonstrated no disease progression. The 1-, 2-, and 3-year overall survival was 96.2%, 90.5%, and 70%, respectively. The patients were free from systemic oncologic therapy following 20 (54%) sessions, with a mean treatment break of 19.1 months. CONCLUSIONS: The PCA of lymph node oligometastases is feasible and safe, and offers promising local tumor control at midterm follow-up.

Safety and oncologic efficacy of percutaneous MRI-guided cryoablation of intraparenchymal renal cancers.

PURPOSE: The purpose of this study was to evaluate the safety and oncologic efficacy of percutaneous magnetic resonance imaging (MRI)-guided cryoablation of intraparenchymal renal cancer. MATERIALS AND METHODS: Between February 2009 and August 2019, 31 consecutives patients with 31 entirely intraparenchymal biopsy-proven renal cancers were treated with cryoablation under MRI-guidance in our institution, and were retrospectively included. There were 20 men and 11 women with a mean age of 68.5±12.5 (SD) (range: 40-91years). Patient, tumor- and procedure-related, and follow-up data were retrospectively collected and analyzed. Local recurrence free (LRFS), metastasis free (MFS), disease free (DFS), cancer specific (CSS), and overall survivals (OS) were calculated. RESULTS: Primary and secondary technical efficacy rates were 94% and 100%, respectively. Median follow-up was 27months. Seven (7/31; 23%) minor complications were noted in 7 patients. Patients showed a significant decline of the estimated glomerular filtration rate (eGFR) between baseline and nadir (mean basal eGFR 65.9±22.4 [SD] mL/min/1.73m2vs. mean nadir eGFR 52.8±26.0 [SD] mL/min/1.73m2; P<0.001), but only two showed a clinically significant renal function decline. Three-year estimates of primary and secondary LRFS, MFS, and DFS were 64% (95% confidence interval [CI]: 47-87%), 89% (95% CI: 78-99%), 83% (95% CI: 77-98%), and 45% (95% CI: 28-73%), respectively. No patients died due to renal cancer evolution (three-year CSS of 100%; 95% CI: 100-100%). One patient died 52months after the percutaneous treatment due to cryoablation-unrelated causes (three-year OS of 100%; 95% CI: 100-100%). CONCLUSION: MRI-guided percutaneous cryoablation for intraparenchymal renal cancer offers good oncologic outcomes with acceptable complication rates and renal function worsening.

Vertebral augmentation reduces the 12-month mortality and morbidity in patients with osteoporotic vertebral compression fractures.

OBJECTIVES: To investigate the 12-month all-cause mortality and morbidity in patients with osteoporotic vertebral compression fractures (OVCFs) undergoing vertebroplasty/balloon kyphoplasty (VP/BKP) versus non-surgical management (NSM). METHODS: Following a Medline and EMBASE search for English language articles published from 2010 to 2019, 19 studies reporting on mortality and morbidity after VP/BKP in patients with OVCFs were selected. The 12-month timeline was set due to the largest amount of data availability at such time interval. Estimates for each study were reported as odds ratios (OR) along with 95% confidence intervals (CI) and p values. Fixed or random-effects meta-analyses were performed. All tests were based on a two-sided significance level of 0.05. RESULTS: Pooled OR across 5 studies favored VP/BKP over NSM in terms of 12-month all-cause mortality (OR: 0.81 [95% CI: 0.46-1.42]; p = .46). Pooled OR across 11 studies favored VP/BKP over NSM in terms of 12-month all-cause morbidity (OR: 0.64 [95% CI: 0.31-1.30]; p = .25). Sub-analysis of data dealing with 12-month infective morbidity from any origin confirmed the benefit of VP/BKP over NSM (OR: 0.23 [95% CI, 0.02-2.54]; p = .23). CONCLUSION: Compared to NSM, VP/BKP reduces the 12-month risk of all-cause mortality and morbidity by 19% and 36%, respectively. Moreover, VP/BKP reduces by 77% the 12-month risk of infection from any origin. KEY POINTS: • Compared to non-surgical management, vertebral augmentation reduces the 12-month risk of all-cause mortality by 19% and all-cause morbidity by 36%. • Vertebral augmentation reduces the 12-month risk of infection morbidity from any origin by 77%.

Radiomics in the evaluation of lung nodules: Intrapatient concordance between full-dose and ultra-low-dose chest computed tomography.

PURPOSE: The purpose of this study was to retrospectively evaluate the quantitative and qualitative intrapatient concordance of pulmonary nodule risk assessment by commercially available radiomics software between full-dose (FD) chest-CT and ultra-low-dose (ULD) chest CT. MATERIALS AND METHODS: Between July 2013 and September 2015, 68 patients (52 men and16 women; mean age, 65.5±10.6 [SD] years; range: 35-87 years) with lung nodules≥5mm and<30mm who underwent the same day FD chest CT (helical acquisition; 120kV; automated tube current modulation) and ULD chest CT (helical acquisition; 135kV; 10mA fixed) were retrospectively included. Each nodule on each acquisition was assessed by a commercial radiomics software providing a similarity malignancy index (mSI), classifying it as "benign-like" (mSI<0.1); "malignant-like" (mSI>0.9) or "undetermined" (0.1≤mSI≤0.9). Intrapatient qualitative agreement was evaluated with weighted Cohen-Kappa test and quantitative agreement with intraclass correlation coefficient (ICC). RESULTS: Ninety-nine lung nodules with a mean size of 9.14±4.3 (SD) mm (range: 5-25mm) in 68 patients (mean 1.46 nodule per patient; range: 1-5) were assessed; mean mSI was 0.429±0.331 (SD) (range: 0.001-1) with FD chest CT (22/99 [22%] "benign-like", 67/99 [68%] "undetermined" and 10/99 [10%] "malignant-like") and mean mSI was 0.487±0.344 (SD) (range: 0.002-1) with ULD chest CT (20/99 [20%] "benign-like", 59/99 [60%] "undetermined" and 20/99 [20%] "malignant-like"). Qualitative and quantitative agreement of FD chest CT with ULD chest CT were "good" with Kappa value of 0.60 (95% CI: 0.46-0.74) and ICC of 0.82 (95% CI: 0.73-0.87), respectively. CONCLUSION: A good agreement in malignancy similarity index can be obtained between ULD chest CT and FD chest CT using radiomics software. However, further studies must be done with more case material to confirm our results and elucidate the diagnostic capabilities of radiomics software using ULD chest CT for lung nodule characterization by comparison with FD chest CT.

Percutaneous Image-Guided Anterior Screw Fixation of the Odontoid Process.

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.

Hydrodissection of the Retro-Sternal Space to Protect the Pericardium During Sternal Cryoablation.

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.

Percutaneous MR-Guided Cryoablation of Low-Flow Vascular Malformation: Technical Feasibility, Safety and Clinical Efficacy.

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.