A comparative study assessing the efficacy and safety of radiofrequency ablation versus surgical treatment for osteoid osteoma: retrospective analysis in a single institution.

OBJECTIVE: We aim to evaluate the efficacy of CT-guided percutaneous radiofrequency ablation (RFA) and surgical treatment in osteoid osteoma (OO) treated at the Medical University of Graz. MATERIALS AND METHODS: In a single-institution study, we analysed data from January 2005 to January 2021 of patients with histological/radiological diagnosis of OO. CT and MRI scans were reviewed for typical findings. Means (with SD) and medians (with IQR) were reported for normally and non-normally distributed variables. Differences between groups were assessed using chi-squared tests and t-tests. RESULTS: One hundred nineteen patients (mean age: 21.6 ± 10.9 years; 63.9% males) with confirmed OO were retrospectively evaluated. 73 and 43 patients underwent RFA and surgery, respectively. In three cases, RFA combined with surgery was performed. Pre-intervention, 103 patients (88.8%) had undergone CT, and 101 had an MRI (87.1%). The nidus was confirmed in 82.5% of cases with CTs (85/103) and 63.4% with MRIs (64/101). The majority of nidi were located cortically (n = 96; 82.8%), most frequently in the femur (38 patients, 33.3%) with a median size of 8.0 mm (IQR: 5.0-12.0 mm). Median symptom duration before treatment was 6.0 (IQR: 4.0-13.0) months. The complication rate was 12.1% (14/116; 15.1% RFA vs. 7.0% surgery; p = 0.196). In total, 11.2% of patients had persistent symptoms after one week with clinical success rates of RFA and surgery, 86.3% and 90.7% (p = 0.647), respectively. CONCLUSION: Compared to surgical treatment, CT-guided percutaneous RFA is a safe, minimally invasive, reliable, and efficient treatment option for OO. CRITICAL RELEVANCE STATEMENT: This article critically assesses the diagnosis and treatment of osteoid osteoma, emphasising accurate imaging, and detailing a non-invasive option for effective management. KEY POINTS: • This study analyses 116 cases of OO at one institution, focusing on symptom persistence, recurrence in short-term follow-up, and complications in two study groups. • Surgery showed higher, though not statistically significant, success despite comparable symptom persistence; CT displayed typical OO features more than MRI, regardless of the intramedullary, cortical and subperiosteal location as well as the site of the affected bone. • CT-guided RFA is an effective therapeutic alternative for OO compared to surgical intervention. In case of atypical OO appearance, RFA is not the first-line treatment.

Non-colorectal liver metastases: A review of interventional and surgical treatment modalities.

Liver metastases (LM) occur in up to 90% either simultaneously with the diagnosis of the primary tumor or at a later time-point. While resection of colorectal LM and resection or transplantation of neuroendocrine LM is part of a standard therapy with a 5-year patient survival of up to 80%, resection of non-colorectal and non-neuroendocrine LM is still discussed controversially. The reason for it is the significantly lower survival benefit of all different tumor entities depending on the biological aggressiveness of the tumor. Randomized controlled trials are lacking. However, reviews of case series with ≥100 liver resections are available. They show a 5-year patient survival of up to 42% compared to only <5% in patients without treatment. Risk factors for poor survival include the type of primary tumor, a short interval between resection of the primary tumor and liver resection, extrahepatic manifestation of the tumor, number and size of the LM, and extent of liver resection. Overall, it has recently been shown that a good patient selection, the technical advances in surgical therapy and the use of a risk score to predict the prognosis lead to a significantly better outcome so that it is no longer justified not to offer liver resection to patients with non-colorectal, non- endocrine LM. Since modern therapy of LM is multimodal, the optimal therapeutic approach is decided individually by a multidisciplinary team consisting of visceral surgeons, oncologists, interventional radiologists and radiologists as part of a tumor board.

The Use of a Commercially Available Endovascular Filter Catheter (Capturex®) for Thoracic Endovascular Aortic Repair (TEVAR) in a Patient with a Coral Reef Aorta.

Due to the risk of mobilizing plaque fragments, transfemoral TEVAR is a potentially dangerous procedure in patients with a coral reef aorta. We describe a practical method for transfemoral TEVAR in a patient with a degenerative thoracic aneurysm and a coral reef aorta. After placing a filter catheter in the abdominal aorta via a contralateral percutaneous femoral access, a working channel through the distal thoracic aorta was created with a balloon-expandable stent graft in the coral reef segment. Thereafter, transfemoral TEVAR could be performed successfully, without any complications. The additional use of a percutaneously placed filter catheter potentially allows reduction of peripheral embolism and hence may prevent patients from more invasive treatment.

Influence of safety glasses, body height and magnification on the occupational eye lens dose during pelvic vascular interventions: a phantom study.

OBJECTIVE: By simulating a fluoroscopic-guided vascular intervention, two differently designed radiation safety glasses were compared. The impacts of changing viewing directions and body heights on the eye lens dose were evaluated. Additionally, the effect of variable magnification levels on the arising scattered radiation was determined. METHODS: A phantom head, replacing the operator's head, was positioned at different heights and rotated in steps of 20° in the horizontal plane. Thermoluminescent dosimeters (TLD), placed in the left orbit of the phantom, detected eye lens doses under protected and completely exposed conditions. In a second step, radiation dose values with increasing magnification levels were detected by RaySafe i3 dosimeters. RESULTS: Changing eye levels and head rotations resulted in a wide range of dose reduction factors (DRF) from 1.1 to 8.5. Increasing the vertical distance between the scattering body and the protective eyewear, DRFs markedly decreased for both glasses. Significant differences between protection glasses were observed. Increasing magnification with consecutively decreasing FOV size variably reduced the dose exposure to the eye lens between 47 and 83%, respectively. CONCLUSION: The safety glasses in the study effectively reduced the dose exposure to the eye lens. However, the extent of the protective effect was significant depending on eye levels and head rotations. This may lead to a false sense of safety for the medical staff. In addition, the application of magnification reduced the quantity of scattering dose significantly. To ensure safe working in the Cath-lab, additional use of protective equipment and the differences in design of protective eyewear should be considered. KEY POINTS: • Eye lens dose changes with physical size of the interventionist and viewing direction. • The use of magnification during fluoroscopic-guided interventions reduces scattered radiation.

RFA Guardian: Comprehensive Simulation of Radiofrequency Ablation Treatment of Liver Tumors.

The RFA Guardian is a comprehensive application for high-performance patient-specific simulation of radiofrequency ablation of liver tumors. We address a wide range of usage scenarios. These include pre-interventional planning, sampling of the parameter space for uncertainty estimation, treatment evaluation and, in the worst case, failure analysis. The RFA Guardian is the first of its kind that exhibits sufficient performance for simulating treatment outcomes during the intervention. We achieve this by combining a large number of high-performance image processing, biomechanical simulation and visualization techniques into a generalized technical workflow. Further, we wrap the feature set into a single, integrated application, which exploits all available resources of standard consumer hardware, including massively parallel computing on graphics processing units. This allows us to predict or reproduce treatment outcomes on a single personal computer with high computational performance and high accuracy. The resulting low demand for infrastructure enables easy and cost-efficient integration into the clinical routine. We present a number of evaluation cases from the clinical practice where users performed the whole technical workflow from patient-specific modeling to final validation and highlight the opportunities arising from our fast, accurate prediction techniques.

Computed Tomography Perfusion Following Transarterial Chemoembolization of Hepatocellular Carcinoma: A Feasibility Study in the Early Period.

OBJECTIVES: The aim of this study was to assess the feasibility of computed tomography (CT) perfusion in early follow-up after transarterial chemoembolization (TACE) of hepatocellular carcinoma (HCC). METHODS: Fifteen patients with a total of 16 HCC who were referred to our institution for TACE were included in the study. Computed tomography perfusion was performed within 1 to 3 days before and 4 to 7 days after TACE. Multiphase contrast-enhanced CT was performed 35 (SD, 20) days after TACE. Hepatic arterial blood flow and portal venous blood flow, as well as the perfusion index (PI), were calculated for each HCC using the dual input maximum slope method. Visual grading of the PI and visual grading of the amount of deposition of embolic material within the HCC were performed using a 6-step scale. Differences in perfusion before and after TACE and correlation of perfusion before TACE with the amount of embolization material depositions 1 week and 1 month after TACE were tested. RESULTS: No statistically significant correlation was found between pre-TACE perfusion parameters and the amount of embolization material deposition in the post-TACE studies. There was no statistically significant difference between pre- and post-TACE arterial blood flow and portal venous blood flow, whereas PI was significantly lower after TACE. Congruently, visual grading of PI was statistically significantly lower after TACE. There was no statistically significant difference in quantitative pre-TACE and post-TACE PI between tumors, which showed hypervascularization in the multiphase follow-up CT and tumors that did not show hypervascularization. However, tumors that showed hypervascularization in the multiphase follow-up CT had significantly higher visual grading of PI after TACE than tumors that did not show hypervascularization. CONCLUSIONS: Our findings indicate that visual interpretation of the PI of HCC derived from dual-input maximum slope CT perfusion may be an early predictor of response to TACE.

Immunohistochemical and radiological characterization of wound healing in porcine liver after radiofrequency ablation.

BACKGROUND: Radiofrequency ablation (RFA) is a minimal invasive therapeutic option for patients with hepatocellular carcinoma or liver metastases. We investigated RFA-induced cellular changes in the liver of pigs. MATERIAL AND METHODS: Healthy pigs (n=18) were sacrificed between day 0 and 3 months after RFA. The wound healing process was evaluated by computed tomography (CT), chromotrope anilinblue (CAB) staining of large-scale and standard tissue sections. Immunohistochemistry (IHC) for heat shock protein 70, Caspase-3, Ki67, Reelin, Vinculin, Vimentin and α-SMA was perfomed. RESULTS: One day after RFA, CAB staining showed cell damage and massive hyperaemia. All IHC markers were predominantly expressed at the outer borders of the lesion, except Reelin, which was mainly detected in untreated liver regions. By staining for Hsp70, the heat stress during RFA was monitored, which was most distinct 1-2 days after RFA. CT revealed decreased lesion size after one week. Development of a Vimentin and α-SMA positive fibrotic capsule was observed. CONCLUSION: In the early phase signs of cell damage, apoptosis and proliferation are dominant. Reduced expression of Reelin suggests a minor role of hepatic stellate cells in the RFA zone. After one week myofibroblasts become prominent and contribute to the development of the fibrotic capsule. This elucidates the pathophysiology of RFA and could contribute to the future optimization of RFA procedures.

Is Embolization an Effective Treatment for Recurrent Hemorrhage After Hip or Knee Arthroplasty?

BACKGROUND: Spontaneous recurrent hemorrhage after arthroplasty of the hip or knee is a rare condition. In patients who do not have coagulopathy, the likeliest etiology for hemarthrosis is hypertrophic vascular synovium. Treatments include arthroscopic or open synovectomy, or angiography with embolization; however, because the condition is rare, seldom reported, and debilitating, small case series characterizing the efficacy of any approach are important to allow a collective experience with this condition to emerge. QUESTIONS/PURPOSES: We attempted to (1) determine whether angiography with embolization can prevent recurrent hemarthrosis after hip or knee arthroplasty in a small series of patients with or without coagulopathy, and (2) evaluate complications associated with this intervention. METHODS: Between 2005 and 2014, seven patients presented with spontaneous, recurrent hemarthroses. One patient had polycythemia vera and factor XIII deficiency as underlying illnesses. All patients were treated with selective transarterial embolization, and all had followup at a minimum of 12 months (range, 12-102 months; median, 74 months). Other treatments during this time included hematoma removals and flap operations in one patient, and indications for transarterial embolization included recurrent hemarthrosis. The patients included six men and one woman with a median age of 72 years (range, 61-78 years). Five patients underwent one or more reoperations before transarterial embolization. A diagnostic workup for coagulopathy was performed in all patients; one patient was identified to have polycythemia ruba vera and factor XIII deficiency, however the patient still was treated with transarterial embolization because it was perceived to be the least invasive of available options. No other patients had a diagnosis of coagulopathy. Angiography showed hypervascularity in all patients and a contrast agent showed extravasation in two. Selective transarterial embolization of branches of the internal iliac artery, common femoral artery, deep femoral artery, or the popliteal artery was performed with polyvinyl alcohol particles, microspheres, and/or coils. Patients were followed clinically during 12 to 102 months (median, 74 months) to determine whether the hemorrhages recurred. RESULTS: Technical success was achieved in all patients. No procedure-related complications were reported. On followup, recurrent hemorrhage was reported in one patient who had a diagnosis of coagulopathy before the procedure. He underwent three reinterventions and five reoperations. Three months after initial embolization, a flap procedure was performed. CONCLUSIONS: In a small series of patients with a minimum followup of 1 year, we found selective transarterial embolization to be effective in patients without underlying coagulopathy in preventing recurrences of spontaneous recurrent hematoma or hemarthrosis of the hip and the knee. This condition is rare, therefore comparative trials are unlikely to be done. Because transarterial embolization is relatively low risk and generally well tolerated, we consider it to be a reasonable approach for consideration with other options such as arthroscopic or open synovectomy and revision arthroplasty. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Effect of hyperthermia on liver cell lines: important findings for thermal therapy in hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma is the fifth most common malignant tumour, with a high mortality rate. This study aimed to investigate the effect of hyperthermia on HepG2 and LX-1 cell lines to gain more information on thermal treatment of liver tumours. MATERIALS AND METHODS: The cell lines HepG2, LX-1 and their co-cultures were heated from 55°C to 85°C for different time spans. After heat exposure, metabolic activity was measured immediately, and after 24 h and 48 h using the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) (MTS) test to assess how many cells had survived heating. RESULTS: Our results show highly significant differences between the temperature tolerance of HepG2 and LX-1 cells. Alone, HepG2 cells are most sensitive to heat-induced cell death, their sensitivity decreased with rising percentages of LX-1 cells in the co-culture. CONCLUSION: Our results suggest that the outcome of thermal cancer therapy is dependent on the temperature and the grade of fibrosis in the treated livers.

Ibandronate prevents bone loss and reduces vertebral fracture risk in male cardiac transplant patients: a randomized double-blind, placebo-controlled trial.

Bone loss and fractures are common complications after cardiac transplantation (CTP). The aim of this study was to investigate whether intravenous ibandronate is an effective preventive option. Thirty-five male cardiac transplant recipients received either ibandronate (IBN) 2 mg intravenously every 3 mo or matching placebo (CTR) in addition to 500 mg calcium carbonate and 400 IE vitamin D(3). Sera were collected at CTP and every 3 mo thereafter. At baseline and 6 and 12 mo, standardized spinal X-rays and BMD measurements were taken. Bone biopsies were taken at CTP and after 6 mo from six patients. In the IBN group, 13% of the patients sustained a new morphometric vertebral fracture compared with 53% in the CTR group (absolute risk reduction [ARR], 40%; relative risk reduction [RRR], 75%; p = 0.04). BMD remained unchanged with IBN treatment but in the CTR group decreased at the lumbar spine by 25% and at the femoral neck by 23% (both p < 0.0001) over the 1-yr period. Serum bone resorption markers carboxy-terminal telopeptide region of type I collagen (sCTX) and TRACP 5b were significantly increased in the CTR group and decreased in the IBN group at all time points compared with baseline. In contrast, both osteocalcin and bone-specific alkaline phosphatase levels showed, after a similar decrease over the first 3 mo in both groups, a marked rise in the CTR subjects and steadily declining levels in the IBN patients throughout the remainder of the study period. Three paired biopsies were available from each group. Despite the small sample size, a difference in the relative change of eroded surface (68% in the CTR versus -23% in the IBN group, p < 0.05) could be shown. Intravenous IBN reduced fractures, preserved bone mass, and prevented uncoupling of bone formation and resorption after CTP. The favorable effects on bone turnover were also supported by histomorphometric findings.