Radio-frequency Technique Research Articles

EHIT after thermoablation

SummaryAim: After 10 years of experience, we evaluated the incidence and management of endothermal heat-induced-thrombosis (EHIT), i.e. saphenous vein thrombosis following endothermic treatment of saphenous vein re-flux.Methods: From 2006 to 2016 data were retrospectively collected on 840 patients undergoing saphenous vein treatment by laser and radiofrequency technique. All patients were treated with tumescent local anaesthesia in an ambulatory setting to promote early mobilization. Class II compression stockings and heparin were recommended for 5 days post-operatively.Results: EHIT was observed in 15 patients from a total of 992 saphenous veins which were evaluated (1,5 %). 14 patients treated by EVLA had EHIT 1, one patient by RFA had EHIT 2, complicated by pulmonary embolism. All EHIT patients were treated by low weight molecular heparin. 980 nm laser and bare-tip fibres had been used in EVLA-EHIT patients. EHIT was not observed in patients treated by 1470 nm laser and radial fibres.Conclusions: Latest generation technology, the ambulatory setting and local anaesthesia probably contributed to the low incidence of EHIT reported. Further studies are necessary for a better acquaintance of these complications and to facilitate the development of specific guidelines.

Radiofrequency ablation of varicose veins

SummaryBackground: In the search of alternative techniques to high ligation and stripping (HL/S) in the treatment of varicose veins, catheter-ablation methods have been implemented since 1998. Besides endovenous laser techniques (ELT) radiofrequency ablation (RFA) is a successful device in treating insufficiency of the Great (GSV) and Small saphenous vein (SSV). Methods: This review article sums up publications on Closure Plus™, ClosureFAST™, RFITT® (Celon Method), and EVRF®. It discusses the actually favorized treatment protocols and study results. Results of meta-analysis are presented, too.Results: The Closure Plus™ catheter was the first radiofrequency technique to be licensed in Europe in 1998. Trials and meta-analyzes show occlusion rates of 81–89 % after 5 years. The consecutive technique was the ClosureFAST™ (CLF) catheter that was introduced in 2007 and offered more standardization in treatment. Published data show occlusion rates of 98 % after 5 years and low profile on complications. Also in 2007 a bipolar radiofrequency technique called RFITT was presented. Due to lack of standards in treatment protocol it could not get accepted as well as CLF despite of good treatment results (92–98 % occlusion rates after 12 months) and low complications. A new RFA device called EVRF® shows weak evidence so far.Conclusion: Radiofrequency ablation of varicose veins has become a well-established treatment alternative to HL/S mostly represented by CLF.

MEMS-Based Flexible Force Sensor for Tri-Axial Catheter Contact Force Measurement.

Atrial fibrillation (AFib) is a significant healthcare problem caused by the uneven and rapid discharge of electrical signals from pulmonary veins (PVs). The technique of radiofrequency (RF) ablation can block these abnormal electrical signals by ablating myocardial sleeves inside PVs. Catheter contact force measurement during RF ablation can reduce the rate of AFib recurrence, since it helps to determine effective contact of the catheter with the tissue, thereby resulting in effective power delivery for ablation. This paper presents the development of a three-dimensional (3D) force sensor to provide the real-time measurement of tri-axial catheter contact force. The 3D force sensor consists of a plastic cubic bead and five flexible force sensors. Each flexible force sensor was made of a PEDOT:PSS strain gauge and a PDMS bump on a flexible PDMS substrate. Calibration results show that the fabricated sensor has a linear response in the force range required for RF ablation. To evaluate its working performance, the fabricated sensor was pressed against gelatin tissue by a micromanipulator and also integrated on a catheter tip to test it within deionized water flow. Both experiments simulated the ventricular environment and proved the validity of applying the 3D force sensor in RF ablation.

Ablación de fibrilación auricular: primera serie colombiana de crioablación con balón

IntroductionPulmonary vein isolation using balloon cryoablation is a innovative technique for managing atrial fibrillation with a high efficacy rate. Its recent introduction and approval by the Colombian National Institute for Medicine and Food Surveillance in our field offers an alternative to the traditional point-by-point radiofrequency isolation. MethodsStarting May 2014, all patients who underwent pulmonary vein isolation with cryoablation were registered prospectively in a form that had been previously designed specifically for this purpose. ResultsBetween May 2014 and August 2015, 31 balloon cryoablations were performed in 31 patients (23 men, 74%) with an average age of 59±11.4 years (range from 34 to 72 years). The most frequent indication was paroxysmal atrial fibrillation (23 patients, 74%), with 4 cases of persistent atrial fibrillation (13%) in the presence of a structurally normal heart. The procedure lasted a total of 152.6±46.1minutes with a fluoroscopy time of 51±16minutes, observing a decrease in the time as the learning curve progressed. Three of the 31 patients (9.7%) developed diaphragmatic paralysis, two of whom recovered motility during the procedure and the other patient recovered motility after one month. ConclusionsCryoablation is a fast and reproducible technique for pulmonary vein isolation in a high complexity electrophysiology service. With a short learning curve, it is a valuable alternative to point-by-point radiofrequency isolation, in a group with previous experience in pulmonary vein isolation by means of the traditional radiofrequency technique. Minor complications rate was similar to what was reported in literature and no major complications were developed in this initial group.

A New Radiofrequency Ablation Procedure to Treat Sacroiliac Joint Pain

Background: Low back pain may arise from disorders of the sacroiliac joint in up to 30% of patients. Radiofrequency ablation (RFA) of the nerves innervating the sacroiliac joint has been shown to be a safe and efficacious strategy. Objectives: We aimed to develop a new RFA technique to relieve low back pain secondary to sacroiliac joint disorders. Study Design: Methodology development with validation through prospective observational non-randomized trial (PONRT). Setting: Academic multidisciplinary health care system, Ohio, USA. Methods: We devised a guide-block to facilitate accurate placement of multiple electrodes to simultaneously ablate the L5 dorsal ramus and lateral branches of the S1, S2, and S3 dorsal rami. This was achieved by bipolar radiofrequency ablation (b-RFA) to create a strip lesion from the lateral border of the base of the sacral superior articular process (L5-S1 facet joint) to the lateral border of the S3 sacral foramen. We applied this technique in 31 consecutive patients and compared the operating time, x-ray exposure time and dose, and clinical outcomes with patients (n = 62) who have been treated with the cooled radiofrequency technique. Patients’ level of pain relief was reported as < 50%, 50 – 80%, and > 80% pain relief at one, 3, 6, and 12 months after the procedure. The relationship between RFA technique and duration of pain relief was evaluated using interval-censored multivariable Cox regression. Results: The new technique allowed reduction of operating time by more than 50%, x-ray exposure time and dose by more than 80%, and cost by more than $1,000 per case. The percent of patients who achieved > 50% pain reduction was significantly higher in the b-RFA group at 3, 6, and 12 months follow-up, compared to the cooled radiofrequency group. No complications were observed in either group. Limitations: Although the major confounding factors were taken into account in the analysis, use of historical controls does not balance observed and unobserved potential confounding variables between groups so that the reported results are potentially confounded. Conclusion: Compared to the cooled radiofrequency ablation (c-RFA) technique, the new b-RFA technique reduced operating time by more than 50%, decreased x-ray exposure by more than 80%, and cut the cost by more than $1000 per case. The new method was associated with significantly improved clinical outcomes despite the limitations of the study design. Thus this new technique appeared to be safe, efficacious, and cost-effective. Key words: Sacroiliac joint pain, sacroiliac joint, low back pain, radiofrequency ablation (RFA), bipolar radiofrequency ablation (b-RFA), cooled radiofrequency ablation (c-RFA), cost-effectiveness

Pulse-Dose Radiofrequency in Athletic Pubalgia: Preliminary Results.

Chronic pubalgia affects around 10% of athletes. To determine the role of pulse-dose radiofrequency (PDRF) in athletes with chronic pubalgia and investigate the causes with imaging. Prospective nonrandomized single-group study. PDRF was performed on 32 patients with a chronic pain that had been refractory to conservative therapies during the last 3 mo. The genital branches of the genitofemoral, ilioinguinal, and iliohypogastric nerves and the obturator nerve were the goals of treatment. A 10-cm, 20-gauge cannula was inserted with a percutaneous access on the upper and lower edges of the iliopubic branch. After the spindle was removed, a radiofrequency needle with a 10-mm "active tip" was inserted. The radiofrequency technique was performed with 1200 pulses at 45 V and 20-ms duration, followed by a 480-ms silent phase. The follow-up with a clinical examination was performed at 1, 3, 6, and 9 mo after the procedure. During the follow-up visits, the patients were asked to rate their pain on a 0-10 VAS scale. All of the enrolled patients completed the study. Mean VAS score before the treatment was 8.4 ± 0.6. Twenty-four patients had a reduction of pain VAS scores more than 50% during all follow-up visits and started training and physiotherapy in the days after the radiofrequency procedure. Six patients, each treated 2 times, had a reduction more than 50% of VAS scores and could start training and physiotherapy only after the 2nd procedure. One patient had no pain relief with 2 treatments. Pain intensity decreased up to 9 mo in 31 patients (mean VAS scores 3.4 ± 0.5 at 6 mo and 3.8 ± 0.9 at 9 mo). No complications were observed. PDRF is an effective and safe technique in management of chronic pubalgia in athletes.

Design, Implementation, and Fundamental Limits of Image and RF Based Wireless Capsule Endoscopy Hybrid Localization

Precise localization of Wireless Capsule Endoscopy (WCE) inside the curly, long, and compact small intestine remains a challenging problem facing researchers for more than a decade. Conventional Radio Frequency (RF) localization techniques, commonly used in outdoor and indoor area, have demonstrated a few centimeters accuracy when applying to the inside of human body. In this paper, using 3D Posterior Cramer-Rao Lower Bound (PCRLB) as a framework for performance evaluation, we demonstrated that millimetric accuracy can be achieved using hybrid RF and image processing localization technique. This level of accuracy enables precise simultaneous localization and mapping of the WCE movement path inside the small intestine. Using the PCRLB framework, we provided in-depth analysis on hybrid localization performance regarding the effects of WCE movement estimation, the effects of system bandwidth as well as the effects of on-body sensor numbers and placements.

Successful use pulsed radiofrequency spinal ganglions in patient with chronic stump pain. Case report

About 50-85% of patients suffer from stump and phantom pain after amputations. These chronic pain conditions are often debilitating and result in disability, sleep and psychosocial disorders, impairment of day-work and the substantial decline in the quality of life. In some patients pharmaceutical therapy may fail to bring satisfactory pain relief or follows severe adverse events. Operations such as rhizotomy, cordotomy and stump revision are often unsuccessful in treating post-amputation chronic pain. The solitary case reports about the using of minimally invasive technique of pulsed radiofrequency (PRF) for treatment of chronic stump and phantom pain have been published only. Our current clinical observation is about successful using of the PRF spinal ganglions in patient with chronic pharmaceutical-resistant post-amputation stump pain.

TREATMENT OF LUMBAR HERNIAS BY ENDOSCOPIC NUCLEOPLASTY WITH RADIOFREQUENCY

ABSTRACT Objective: To evaluate the postoperative outcomes of minimally invasive technique for treating lumbar disc herniation in patients undergoing percutaneous endoscopic nucleoplasty with radiofrequency in the center of minimally invasive procedures Veracruz (CEMIVER) of the HRAEV.. Methods: A descriptive, comparative, ambispective and longitudinal study. The clinical records of patients who underwent herniated disc surgery were reviewed from March 2010 to March 2015. Inclusion criteria were individuals of both sexes, aged 18-65 years, with disc herniation diagnosis by MRI, evocative discography (pain) and clinical evaluation. The variables were analyzed by VAS, Oswestry disability index for functional assessment and Macnab criteria for modified retrospective cross clinical classification. Results: 161 patients were included, 81 female and 80 male, aged between 18 and 65 years with severe (83.8%) and moderate (16.2%) disability according to the Oswestry disability index; the total of excellent results was 83.8%, 9.5% were good, 4.8% were median and 1.9% were poor results, according to the Macnab criteria; the average time of surgery was 84 minutes per procedure, and the postoperative average bleeding was 65 ml. Of the total, 87.4% of the patients were on an outpatient basis and 7.6% had a short hospital stay.. Conclusion: It was found that percutaneous endoscopic nucleoplasty with radiofrequency technique is a procedure that offers great benefits for patients with lumbar disc herniation, including performing it under local anesthesia, with clear visualization of the surgical field, minimal pain, little bleeding, shorter operative time, does not cause instability of anatomical structures and has minimal rate of complications.

Incisionless transcranial MR-guided focused ultrasound in essential tremor: cerebellothalamic tractotomy

BackgroundAlready in the late 1960s and early 1970s, targeting of the “posterior subthalamic area (PSA)” was explored by different functional neurosurgical groups applying the radiofrequency (RF) technique to treat patients suffering from essential tremor (ET). Recent advances in magnetic resonance (MR)-guided focused ultrasound (MRgFUS) technology offer the possibility to perform thermocoagulation of the cerebellothalamic fiber tract in the PSA without brain penetration, allowing a strong reduction of the procedure-related risks and increased accuracy. We describe here the first results of the MRgFUS cerebellothalamic tractotomy (CTT).MethodsTwenty-one consecutive patients suffering from chronic (mean disease duration 29.9 years), therapy-resistant ET were treated with MRgFUS CTT. Three patients received bilateral treatment with a 1-year interval. Primary relief assessment indicators were the Essential Tremor Rating Scale (Fahn, Tolosa, and Marin) (ETRS) taken at follow-up (3 months to 2 years) with accent on the hand function subscores (HF16 for treated hand and HF32 for both hands) and handwriting. The evolution of seven patients with HF32 above 28 points over 32 (group 1) differentiated itself from the others’ (group 2) and was analyzed separately. Global tremor relief estimations were provided by the patients. Lesion reconstruction and measurement of targeting accuracy were done on 2-day post-treatment MR pictures for each CTT lesion.ResultsThe mean ETRS score for all patients was 57.6 ± 13.2 at baseline and 25.8 ± 17.6 at 1 year (n = 10). The HF16 score reduction was 92 % in group 2 at 3 months and stayed stable at 1 year (90 %). Group 1 showed only an improvement of 41 % at 3 months and 40 % at 1 year. Nevertheless, two patients of group 1 treated bilaterally had an HF16 score reduction of 75 and 88 % for the dominant hand at 1 year after the second side. The mean patient estimation of global tremor relief after CTT was 92 % at 2 days and 77 % at 1-year follow-up.ConclusionsCTT with MRgFUS was shown to be an effective and safe approach for patients with therapy-refractory essential tremor, combining neurological function sparing with precise targeting and the possibility to treat patients bilaterally.

Ex-vivo investigation on the potential of 1470 nm diode laser light for enucleation of uterine leiomyoma

Abstract Background and objective: Patients suffering from uterine leiomyoma are often treated by hysterectomy or organ preserving myoma enucleation using electrosurgical, ultrasonic or radio-frequency techniques. Considerable thermal tissue damage leads to the development of scar formation which in the long term may result in complications during pregnancy. Therefore alternative techniques are required. Materials and methods: After ethical approval, human uteri myomatosus were used to investigate the interaction of 1470 nm diode laser light (Medilas D MultiBeam; Dornier MedTech Laser GmbH, Weßling, Germany) during surgical procedures (laser mode, continuous wave; laser power, 5–30 W; fiber core diameter, 600 μm; cutting velocity, 3 mm/s). Macroscopic and microscopic evaluation was performed to improve understanding of tissue ablation and coagulation processes. Additionally laser-assisted ex-vivo myoma enucleation procedures were performed to assess handling and applicability. Descriptive and correlation statistics were used for evaluation. Results: The macroscopic visible coagulation rim was calculated to be at a maximum of ~550 μm in lateral direction (superficial width), and ~300 μm in axial plane (sagittal depth). Microscopic examination of hematoxylin and eosin stained sagittal tissue slices showed a largest ablation depth of 279.1±186.8 μm and a maximum irreversibly damaged remaining tissue depth of 628.7±354.3 μm when a laser power of 30 W was applied. The ratio of the remaining tissue and ablation depth indicates that increased applied laser power results in a faster ablation than coagulation into the depth. Hands-on ex-vivo myoma enucleation at power levels of 20–25 W showed an ideal preparation situation with the potential for sufficient surface coagulation when the fiber-tissue distance is adjusted to 5–10 mm. Conclusion: Sufficient and effective ablation and coagulation of uterus myomatosus tissue and the ex-vivo myoma enucleation showed the potential of the 1470 nm diode laser as an innovative surgical tool for myoma enucleation. Based upon this study it should be clinically validated whether this procedure could become an alternative application in endoscopic surgery in gynecology.

Apneea în somn la copil – tratament chirurgical

Obstructive sleep apnea is characterized by recurrent episodes of partial or complete obstruction of upper respiratory airways which appear during sleep and lead to the decrease of oxygen saturation and numerous awakenings. The symptomatology in pediatric obstructive sleep apnea is very different from the adult type in many aspects. The gold standard examination for diagnosis and evaluation of severity is polysomnography. The authors present their experience in the surgical tratament of children with obstructive sleep apnea. It is outlined a group of patient enrolled during a period of 5 years (2010-2014) who had their tonsils reduced through coblation and radiofrequency techniques.

Magnetic Resonance-Based Wireless Power Transmission through Concrete Structures

As civil infrastructures continue to deteriorate, the demand for structural health monitoring (SHM) has increased. Despite its outstanding capability for damage identification, many conventional SHM techniques are restricted to huge structures because of their wired system for data and power transmission. Although wireless data transmission using radio-frequency techniques has emerged vis-a-vis wireless sensors in SHM, the power supply issue is still unsolved. Normal batteries cannot support civil infrastructure for no longer than a few decades. In this study, we develop a magnetic resonance-based wireless power transmission system, and its performance is validated in three different mediums: air, unreinforced concrete, and reinforced concrete. The effect of concrete and steel rebars is analyzed.

ARFTG May 2015

Discusses the Automatic Radio Frequency Techniques Group (ARFTG), a technical organization interested in all aspects of RF and microwave test and measurement. ARFTG was originally set up in 1972 to help end-users get the most from the latest generation of test and measurement equipment.

PP-119 Treatment of Atrial Fibrillation with Pulmonary Vein Isolation: A Single Center Experience

The American Journal of Cardiology MARCH 26e29, 2015 11 IN AND C Acute procedural success rate ( 3 PV isolation) was 97.2 % with radiofrequency technique (82.2% paroxysmal AF, 18.8% persistan AF). Major complications were observed in one of patients which treated with radiofrequency technique (cardiac perforation). PVI with radiofrequency, mean procedural and fluoroscopy times were 124.2 25.2 (110-210) min and 15.3 6.3 (14-23) min. Additionally, 4 of patients which treated with radiofrequency technique mitral isthmus and roof ablation line were performed together with PVI. At the time of followup, 93.28% of patients were free from AF recurrence. Conclusion: The efficacy and safety of radiofrequency and cryoballoon AF ablation technique was shown due to the acceptable success and low complication rates in either paroxysmal or permanent AF patients. A number of the complications early in the experience of PVI isolation have been addressed, especially with radiofrequency PVI, but further experience is required to increase the efficacy and safety of these techniques.

TÉCNICA DE LIGADURA SUBFASCIAL MINI-INVASIVA DE VENAS PERFORANTES DE LAS PIERNAS

Treatment of incompetent perforator leg veins by minimally invasive subfascial ligation Perforator vein incompetence is a specific form of lower extremitiy venous insufficiency characterized by localized hyperpigmentation, venous ulceration or recurrence of varicose veins. Surgical treatment ranges from the extensive conventional open subfascial ligation to percutaneous radiofrequency or laser techniques with unknown late outcome. A minimally invasive technique of subfascial ligation through small incisions described by Queral, with acceptable results, has been successfully used and improved in recent years by our group. Details of the technique and pre-operative managment are described.

Evaluation of early alterations of common carotid artery structure and function in patients with hypertriglyceridemia using ultrasound radio-frequency analyzing technique

Objective To evaluate the clinical value of early alterations of carotid arterial intima-media thickness (IMT) and elastic function in patients with hypertriglyceridemia (HTG) using ultrasound radio-frequency technique.Methods 48 patients (triglyceride value ≥ 1.8 mmol/L) were chosen as HTG group.Quantitative intimamedia thickness (QIMT) and quantitative arterial stiffness (QAS) techniques were used to observe the alterations of carotid arterial IMT and elastic index,including diameter of carotid artery (D),distensibility coefficient (DC),compliance coefficient (CC),elasticity coefficient (α),elasticity coefficient (β) and pulse wave velocity (PWV).50 healthy subjects were recruited in control group.Differences of the above-mentioned parameters were analyzed,as well as the elastic index connections between the two groups.Results IMT,α,β,and PWV index of bilateral carotid arteries in HTG group was higher than that of the control group,while the DC and CC index was lower,and the differences was statistically significant (P＜0.05).Within the groups there were differences between the elastic indexes of bilateral carotid arteries.In control group and the HTG group:CCL＞CCR,αL＞αR,βL＞βR,PWVL＞PWVR.CC was negatively correlated to α,β and PWV (P＜0.05).Meanwhile,there was positive correlation among α,β and PWV (P＜0.05).The differences of D between two groups had no statistical significance (P＞0.05).Conclusions The abnormity of arterial occurs earlier than the morphological change,while the ultrasound radio-frequency technique can provide information of earlier alteration of common carotid arteries structure and elastic function in patients with HTG,which is a significant method of testing early alteration of carotid elastic in patients with HTG. Key words: Ultrasound; Hypertriglyceridemia; Carotid arteries; Early stage

Research on Detection of Distribution and Collision of Wireless Sensor Nodes Based on Radio-Frequency Technique

many factors need to be considered in layout and distribution of wireless sensor nodes; in addition to the general features of common monitoring sensors, such as economic factors, environmental factors, detection accuracy factor, etc, some particular features should be fully considered, such as intensity, large-scale rapid layout, early warning and monitoring of critical structural components and important areas, as well as its redundancy. Basing on the Modal Energy Method, the paper proposes an optimal sensor layout algorithm available in improvement of modal strain energy method, and such the method is simple and quick, with certain practical value.

Egg Quality Prediction Using Dielectric and Visual Properties Based on Artificial Neural Network

Recently, rapid and nondestructive technologies have been developed in the qualification of food products. This research aimed to design and develop an egg qualifying system based on dielectric technology in the range of radio frequency (40 kHz to 20 MHz), machine vision, and artificial neural network (ANN) techniques. Haugh unit, yolk index, yolk/albumen ratio, and yolk weight were studied as quality factors of egg. The designed electronic device was calibrated and evaluated for prediction of the mentioned parameters. The coefficient of determination (R 2) values in the validation of the ANN were 0.998, 0.998, 0.998, and 0.994 for the Haugh unit, yolk index, yolk/albumen, and yolk weight, respectively. In evaluation mode, the mean absolute percent errors (MAPEs) obtained were 5.41, 6.84, 8.79, and 4.24 % for the Haugh unit, yolk index, yolk/albumen, and yolk weight, respectively. Results of the evaluation showed the designed device can be confidently used in the prediction of egg quality indices.

Therapeutic Effects of Radiofrequency and Intranasal Corticosteroid on Rhinomanometry in Patients With Inferior Turbinate Hypertrophy

Background: Inferior turbinate hypertrophy (ITH) is one of the common causes of nasal obstruction. In some case with ITH due to allergic rhinitis medical therapy can be useful and in cases with refractory ITH surgical techniques may be helpful. Although there is no excellence [or superiority] among these surgical methods, radiofrequency (RF) has recently become popular. Objectives: This study compared the therapeutic effects of intranasal corticosteroid and RF in patients with ITH due to allergic rhinitis. Patients and Methods: In this randomized clinical trial, patients with ITH due to allergic rhinitis, referred to Baqiyatallah University of Medical Sciences Allergy Clinic, were randomly assigned to RF and intranasal corticosteroid spray groups (fluticasone 125 µg). Patients were evaluated by the symptoms severity, which were measured by visual analogue scale (0-10 score) and rhinomanometry, four times (before the intervention and the 1st, 3rd and 6th month after the intervention). Data were analyzed by SPSS version 21. Results: Sixty patients with ITH due to allergic rhinitis were evaluated, among which 26 were male and 34 were female. The mean age was 35.5 ± 8.86 years old and the mean body mass index (BMI) was 22.97 ± 3.12 kg/m2. There was no significant difference in demographic data among the groups. All the patients showed significant improvements in symptoms severities and rhinomanometry at all the after intervention visits. The best results were obtained in the 6th month of follow-up. The mean nasal obstruction severity and rhinomanometry results were significantly higher in the RF group at all the after intervention visits (P < 0.05). Conclusions: According to the results, we suggest using RF technique for patients with ITH due to allergic rhinitis, which is an outpatient procedure with local anesthesia; long-term effects of these two therapeutic methods (corticosteroid an RF) could be evaluated in future studies.