A Toolbox of Bone Consolidation for the Interventional Radiologist.

Bone consolidation is increasingly used in the treatment of both benign and malignant bone conditions. Percutaneous vertebroplasty, for example, has been shown to be useful in vertebral compression fractures in the VAPOUR trial which showed its superiority to placebo for pain reduction in the treatment of acute vertebral compressive fractures. Further tools have since been developed, such as kyphoplasty, spinal implants, and even developments in bone cements itself in attempt to improve outcome, such as chemotherapy-loaded cement or cement replacements such as radio-opaque silicon polymer. More importantly, bone fixation and its combination with cement have been increasingly performed to improve outcome. Interventional radiologists must first know the tools available, before they can best plan for their patients. This review article will focus on the tool box available for the modern interventional radiologist.

Long-Term Prognosis of Patients With Coronary Microvascular Disease Using Stress Perfusion Cardiac Magnetic Resonance.

OBJECTIVES: This study investigated the prognosis of coronary microvascular disease (CMD) as determined by stress perfusion cardiac magnetic resonance (CMR) in patients with ischemic symptoms but without significant coronary artery disease (CAD). BACKGROUND: Patients with CMD have poorer prognosis with various cardiac diseases. The myocardial perfusion reserve index (MPRI) derived from noninvasive stress perfusion CMR has been established to diagnose microvascular angina with a threshold MPRI <1.4. The prognosis of CMD as determined by MPRI is unknown. METHODS: Chest pain patients without epicardial CAD or myocardial disease from January 2009 to December 2017 were retrospectively included from 3 imaging centers in Hong Kong (HK). Stress perfusion CMR examinations were performed using either adenosine or adenosine triphosphate. Adequate stress was assessed by achieving splenic switch-off sign. Measurement of MPRI was performed in all stress perfusion CMR scans. Patients were followed for major adverse cardiovascular events defined as all-cause death, acute coronary syndrome (ACS), epicardial CAD development, heart failure hospitalization and non-fatal stroke. RESULTS: A total of 218 patients were studied (mean age 59 ± 12 years; 49.5% male) and the average MPRI of that cohort was 1.56 ± 0.33. Females and a history of hyperlipidemia were predictors of lower MPRI. Major adverse cardiovascular events (MACE) occurred in 15.6% of patients during a median follow-up of 5.5 years (interquartile range: 4.6 to 6.8 years). The optimal cutoff value of MPRI in predicting MACE was found with a threshold MPRI ≤1.47. Patients with MPRI ≤1.47 had three-fold increased risk of MACE compared with those with MPRI >1.47 (hazard ratio [HR]: 3.14; 95% confidence interval [CI]: 1.58 to 6.25; p = 0.001). Multivariate Cox regression after adjusting for age and hypertension demonstrated that MPRI was an independent predictor of MACE (HR: 0.10; 95% CI: 0.03 to 0.34; p < 0.001). CONCLUSIONS: Stress perfusion CMR-derived MPRI is an independent imaging marker that predicts MACE in patients with ischemic symptom and no overt CAD over the medium term.

Performance of a New Blunt-Tip Needle for the Displacement of Critical Structure in Thermal Ablation.

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.

Type B Interrupted Aortic Arch with a Patent Ductus Arteriosus in an Adult Presenting with Secondary Polycythaemia.

Interrupted aortic arch (IAA) is an extremely rare congenital cyanotic heart disease characterized by complete disruption between the ascending and descending aorta. A patent ductus arteriosus (PDA) or other collateral pathways provide blood flow to the distal descending aorta. Mortality is extremely high at early infancy, particularly after closure of the ductus arteriosus. Survival and presentation in adulthood are extremely rare. Here, we illustrate a rare case of type B IAA in an adult who presented with secondary polycythaemia. The blood supply to the descending aorta and beyond was almost solely via a PDA. This case demonstrates the value of multimodality imaging, including CT and MRI, for diagnosis and treatment planning in these patients. LEARNING POINTS: The presence of secondary polycythaemia, as a result of chronic hypoxia, should prompt a search for underlying cyanotic heart disease even in previously undiagnosed adults.Most previous case reports of IAA in adults feature type A; type B IAA in an adult is far less frequently described.MRI has incremental value compared to CT in intracardiac assessment (aortic valve assessment, RV and LV functional assessment, flow measurement) for these patients; in addition, it provides an excellent depiction of the vascular anatomy of the aorta and great vessels.

Complications of Percutaneous Bone Tumor Cryoablation: A 10-year Experience.

Background Percutaneous cryoablation has been shown to be effective in the management of painful bone tumors. However, knowledge of the complication rate and risk factors for complication is currently lacking. Purpose To report the complication rate and associated risk factors for bone tumor cryoablation. Materials and Methods This retrospective study reviewed complications in 239 consecutive patients (131 men and 108 women; median age, 64 years; age range, 6-86 years) who underwent cryoablation of 320 primary or metastatic bone tumors between January 2008 and November 2017. Common Terminology Criteria for Adverse Events was used to categorize complications as major (grade 3-4) or minor (grade 1-2). Multivariable analysis was performed for variables with P values less than .20, including age, tumor location, adjacent critical structures, number of cryoprobes, and Eastern Cooperative Oncology Group performance status (ECOG-PS). Results Among the 320 tumors, the total complication rate was 9.1% (29 of 320; 95% confidence interval [CI]: 6%, 12.2%). The major complication rate was 2.5% (eight of 320; 95% CI: 0.8%, 4.2%), with secondary fracture the most frequent complication (1.2% [four of 320]; mean delay, 71 days); cryoablation site infection, tumor seeding, bleeding, and severe hypotension were each observed in 0.3% (one of 320) of procedures. Minor complications included postprocedural pain (2.2% [seven of 320]), peripheral neuropathy (0.9% [three of 320]), and temporary paresthesia (0.9% [three of 320]). For all complications, associated risk factors included ECOG-PS greater than 2 (odds ratio [OR], 3.1 [95% CI: 3, 7.6]; P = .01), long-bone cryoablation (OR, 17.8 [95% CI: 2.3, 136.3]; P = .01), and use of more than three cryoprobes (OR, 2.5 [95% CI: 1.0, 6.0]; P = .04); for major complications, associated risk factors included age greater than 70 years (OR, 7.1 [95% CI: 1.6, 31.7]; P = .01) and use of more than three cryoprobes (OR, 23.6 [95% CI: 2.8, 199.0]; P = .01). Conclusion Bone tumor cryoablation is safe, with a 2.5% rate of major complications, most commonly secondary fracture (1.2%). Major complications are associated with age greater than 70 years and use of more than three cryoprobes. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Jennings in this issue.

Robotically Assisted CBCT-Guided Needle Insertions: Preliminary Results in a Phantom Model.

AIM: To compare robotic-assisted needle insertions performed under CBCT guidance to standard manual needle insertions. MATERIALS AND METHODS: A homemade robotic prototype was used by two operators to perform robotic and manual needle insertions on a custom-made phantom. Both the operators had no experience with the prototype before starting the trial. The primary endpoint was accuracy (i.e., the minimal distance between the needle tip and the center of the target) between robotic and manual insertions. Secondary endpoints included total procedure time and operators' radiation exposure. The Wilcoxon test was used. A p value less than 0.05 was considered statistically significant. RESULTS: Thirty-three (17 manual, 16 robotic) needle insertions were performed. Mean accuracy for robotic insertion was 2.3 ± 0.9 mm (median 2.1; range 0.8-4.2) versus 2.3 ± 1 mm (median 2.1; range 0.7-4.4) for manual insertion (p = 0.84). Mean procedure time was 683 ± 57 s (median 670; range 611-849) for the robotic group versus 552 ± 40 s (median 548; range 486-621) for the manual group (p = 0.0002). Mean radiation exposure was 3.25 times less for the robotic insertion on comparison to manual insertion for the operator 1 (0.4 vs 1.3 µGy); and 4.15 times less for the operator 2 (1.9 vs 7.9 µGy). CONCLUSION: The tested robotic prototype showed accuracy comparable to that achieved with manual punctures coupled to a significant reduction of operators' radiation exposure. Further, in vivo studies are necessary to confirm the efficiency of the system.

Percutaneous image-guided ablation of bone metastases: local tumor control in oligometastatic patients.

INTRODUCTION: Percutaneous image-guided cryo- (CA) and radiofrequency- (RFA) ablations have been widely used in the treatment of painful bone metastases (BM). However, paucity of data is available for the performance of these treatments when used with a curative intent. The aim of this study is to investigate the local progression free-survival (LPFS) after radical percutaneous image-guided ablation of BM in oligometastatic patients, and to identify predictive factors associated with local tumor progression. MATERIALS AND METHODS: This is a retrospective review of all patients who underwent percutaneous image-guided CA or RFA of BM with a radical intent between 2007 and 2018. RESULTS: Forty-six patients with a total of forty-nine BM underwent percutaneous image-guided CA (N = 37; 75,5%) or RFA (N = 12; 24,5%). Primary malignancies included thyroid (N = 11, 22.5%), breast (N = 21; 42.9%), lung (N = 8; 16.3%) and other (N = 9; 18,3%) cancers. Additional consolidation was performed after ablation in 20.4% cases (N = 10). Mean follow-up was 34.1 ± 22 months. Local progression at the treated site was observed in 28.5% cases (N = 14); 1- and 2-year LPFS was 76.8% and 71.7%, respectively. Size of BM (>2 cm) predicted local tumor progression (p = .002). CONCLUSIONS: Percutaneous image-guided locoregional therapies used in the radical treatment of BM in oligometastatic patients demonstrate significant rates of LPFS providing the size of BM ≤2 cm.