Search results for "frequency [modulation]"
showing 10 items of 569 documents
Primary spinal Burkitt’s lymphoma: Case report and literature review
2021
Background:Burkitt’s lymphoma is a non-Hodgkin B-cell lymphoma, occurring mostly in Equatorial Africa. According to the WHO, classification is three different variants: sporadic, endemic, and immunodeficient-associated. Here, we present a patient with “sporadic” primary epidural Burkitt’s lymphoma resulting in chronic low back pain (LBP).Case Description:A 63-year-old female presented with a 2-month history of LBP and the left lower extremity sciatica. The thoracolumbar MRI showed a L5 irregular, osteolytic epidural lesion that was hypointense on T1-weighted images, hyperintense on STIR studies, and inhomogeneously enhanced with contrast. Additional hypointense lesions were also seen at the…
Healon5 viscoadaptive formulation: Comparison to Healon and Healon GV
2001
Abstract Purpose To compare the rheological characteristics of a viscoadaptive viscoelastic formulation with those of 2 standard ophthalmic viscosurgical devices (OVDs). Setting Department of Ophthalmology, Johannes Gutenberg-University, and Max Planck-Institute for Polymer Research, Mainz, Germany. Methods An independent comparative study of 3 OVDs of sodium hyaluronate (Healon®, Healon GV®, and Healon®5) was performed using the Advanced Rheometric Expansion System to analyze rheologic behavior (eg, dynamic frequency dependence of the complex viscosity) as well as rheological parameters (eg, viscosity at zero shear rate, pseudoplasticity, relaxation time, elastic and viscous modulus). Resu…
The changing scenario of hepatocellular carcinoma in Italy: an update
2021
Background and aims: Epidemiology of hepatocellular carcinoma (HCC) is changing in most areas of the world. This study aimed at updating the changing scenario of aetiology, clinical presentation, management and prognosis of HCC in Italy during the last 15 years. Methods: Retrospective analysis of the Italian Liver Cancer (ITA.LI.CA) database included 6034 HCC patients managed in 23 centres from 2004 to 2018. Patients were divided into three groups according to the date of cancer diagnosis (2004-2008, 2009-2013 and 2014-2018). Results: The main results were: (i) a progressive patient ageing; (ii) a progressive increase of non-viral cases and, particularly, of ‘metabolic’ and ‘metabolic + alc…
Ultrasound-guided ablation for hepatocellular carcinoma: time for a reappraisal?
2015
Ultrasound-guided techniques play a key role in the clinical management of hepatocellular carcinoma. Among these, percutaneous ethanol injection (PEI) was the first technique to be proposed for the treatment of nodular-type hepatocellular carcinoma: the role of PEI was first discussed during the European Association for the Study of the Liver conference held in Barcelona in 2000, 15 years ago. Since then, other techniques have been introduced and radiofrequency ablation now represents the most widely used percutaneous technique. PEI and radiofrequency ablation are widely used in clinical practice. However, only scant progresses in the application of these techniques have been performed over…
Imaging appearance of treated hepatocellular carcinoma
2013
Surgical resection and imaging guided treatments play a crucial role in the management of hepatocellular carcinoma (HCC). Although the primary end point of treatment of HCC is survival, radiological response could be a surrogate end point of survival, and has a key role in HCC decision-making process. However, radiological assessment of HCC treatment efficacy is often controversial. There are few doubts on the evaluation of surgical resection; in fact, all known tumor sites should be removed. However, an unenhancing partial linear peripheral halo, in most cases, surrounding a fluid collection reducing in size during follow-up is demonstrated in successfully resected tumor with bipolar radio…
Needle track seeding following percutaneous procedures for hepatocellular carcinoma.
2009
Neoplastic seeding may arise after diagnostic or therapeutic percutaneous procedures for hepatocellular carcinoma. The true incidence of seeding with hepatocellular carcinoma is difficult to assess precisely, but a significant risk of seeding exists and is greater when performing diagnostic biopsy as compared to therapeutic percutaneous procedures [radiofrequency ablation, radiofrequency ablation (RFA); percutaneous ethanol injection, Percutaneous ethanol injection (PEI)]. Whenever liver transplantation is feasible, diagnostic needle biopsies should be avoided, but RFA and PEI are often needed as “bridge” treatments. The role of adjuvant treatments in reducing the incidence of seeding follo…
Reconstruction of vertebral body after radiofrequency ablation and augmentation in dorsolumbar metastatic vertebral fracture: Analysis of clinical an…
2017
Background: Painful spinal metastases usually occur in malignant neoplastic disease. Treatment for bone metastases has been largely conservative, and it includes the use of high doses of analgesics, radiotherapy, chemotherapy, hormone therapy, and bisphosphonates; however, results are sometimes transient and ineffective. In the presence of neurological involvement a surgical strategy should be considered. Recently, percutaneous procedures such as radiofrequency ablation, vertebroplasty, and kyphoplasty have been introduced as palliative techniques to treat painful vertebral metastases [3, 11, 25]. Methods: In our study we combined the use of radiofrequency ablation with vertebroplasty in th…
Failure mode and effects analysis of skin electronic brachytherapy using Esteya® unit
2016
Purpose: Esteya® (Nucletron, an Elekta company, Elekta AB, Stockholm, Sweden) is an electronic brachytherapy device used for skin cancer lesion treatment. In order to establish an adequate level of quality of treatment, a risk analysis of the Esteya treatment process has been done, following the methodology proposed by the TG-100 guidelines of the American Association of Physicists in Medicine (AAPM). Material and methods: A multidisciplinary team familiar with the treatment process was formed. This team developed a process map (PM) outlining the stages, through which a patient passed when subjected to the Esteya treatment. They identified potential failure modes (FM) and each individual FM…
Modifications in Ventricular Fibrillation and Capture Capacity Induced by a Linear Radiofrequency Lesion
2012
[EN] Introduction and objectives: An analysis was made of the effects of a radiofrequency-induced linear lesion during ventricular fibrillation and the capacity to capture myocardium through high-frequency pacing. Methods: Using multiple epicardial electrodes, ventricular fibrillation was recorded in 22 isolated perfused rabbit hearts, analyzing the activation maps upon applying trains of stimuli at 3 different frequencies close to that of the arrhythmia: a) at baseline; b) after radio-frequency ablation to induce a lesion of the left ventricular free wall (length=10 [1] mm), and c) after lengthening the lesion (length=23 [2] mm). Results: Following lesion induction, the regularity of the r…