Conventional X-ray Fluoroscopy Research Articles

Comparing Low-to-Zero Fluoroscopic Navigation Systems for AVNRT Catheter Ablation: A Network Meta-Analysis.

Low-to-zero fluoroscopic navigation systems lower radiation exposure which improves health outcomes. Conventional x-ray fluoroscopy (CF) has long been the standard to guide to catheter location for cardiac ablation. With advancements in technology, alternative safety navigation systems have been developed. Three primary modalities commonly utilized are three-dimensional electroanatomic mapping (3D-EAM), magnetic navigation system (MNS), and intracardiac echocardiography (ICE), all of which can reduce radiation exposure during the procedure. We aim to compare the efficacy and safety among ICE, EAM, MNS, and CF in ablation of atrioventricular nodal reentrant tachycardia (AVNRT). This is a meta-analysis consisting of observational studies and randomized controlled trials, which evaluated the performance of navigation systems of catheter ablation in AVNRT patients. Primary endpoint was to access the AVNRT recurrence after the procedure during follow-up periods. Secondary endpoints were technical success, fluoroscopic time, fluoroscopic dose area product, radiofrequency ablation time, and adverse events. Random-effect model was applied for pooled estimated effects of included studies. A total of 21 studies (21 CF, 2 ICE, 9 EAM, 11 MNS) including 1716 patients who underwent catheter ablation for AVNRT treatment were analyzed. Of these, 16 were observational studies and 5 were randomized controlled trials. Point estimation of AVNRT recurrence showed ICE exhibited a pooled odds ratio (ORs) of 1.06 (95% confidence interval [CI]: 0.064-17.322), MNS with ORs of 0.51 (95% CI: 0.214-1.219], and EAM with ORs of 0.394 (95% CI: 0.119-1.305) when compared to CF. EAM had significant higher technical success with ORs of 2.781 (95% CI: 1.317-5.872) when compared to CF. Regarding fluoroscopy time, EAM showed the lowest time with mean differences (MD) of -10.348 min (95% CI: -13.385 to -7.3101) and P-score of 0.998. It was followed by MNS with MD of -3.712 min (95% CI: -7.128 to -0.295) and P-score of 0.586, ICE with MD of -1.150 min (95% CI: -6.963 to 4.662) with a P-score of 0.294 compared to CF, which has a P-score of 0.122. There were insignificant adverse events across the procedures. AVNRT ablation navigated by low-to-zero fluoroscopic navigation systems achieves higher efficacy and comparable safety to conventional fluoroscopywhile also reducing risk of radiation exposure time.

Single-shot quantitative x-ray imaging using a primary modulator and dual-layer detector.

Conventional x-ray imaging and fluoroscopy have limitations in quantitation due to several challenges, including scatter, beam hardening, and overlapping tissues. Dual-energy (DE) imaging, with its capability to quantify area density of specific materials, is well-suited to address such limitations, but only if the dual-energy projections are acquired with perfect spatial and temporal alignment and corrected for scatter. In this work, we propose single-shot quantitative imaging (SSQI) by combining the use of a primary modulator (PM) and dual-layer (DL) detector, which enables motion-free DE imaging with scatter correction in a single exposure. The key components of our SSQI setup include a PM and DL detector, where the former enables scatter correction for the latter while the latter enables beam hardening correction for the former. The SSQI algorithm allows simultaneous recovery of two material-specific images and two scatter images using four sub-measurements from the PM encoding. The concept was first demonstrated using simulation of chest x-ray imaging for a COVID patient. For validation, we set up SSQI geometry on our tabletop system and imaged acrylic and copper slabs with known thicknesses (acrylic: 0-22.5cm; copper: 0-0.9mm), estimated scatter with our SSQI algorithm, and compared the material decomposition (MD) for different combinations of the two materials with ground truth. Second, we imaged an anthropomorphic chest phantom containing contrast in the coronary arteries and compared the MD with and without SSQI. Lastly, to evaluate SSQI in dynamic applications, we constructed a flow phantom that enabled dynamic imaging of iodine contrast. Our simulation study demonstrated that SSQI led to accurate scatter correction and MD, particularly for smaller focal blur and finer PM pitch. In the validation study, we found that the root mean squared error (RMSE) of SSQI estimation was 0.13cm for acrylic and 0.04mm for copper. For the anthropomorphic phantom, direct MD resulted in incorrect interpretation of contrast and soft tissue, while SSQI successfully distinguished them quantitatively, reducing RMSE in material-specific images by 38%-92%. For the flow phantom, SSQI was able to perform accurate dynamic quantitative imaging, separating contrast from the background. We demonstrated the potential of SSQI for robust quantitative x-ray imaging. The integration of SSQI is straightforward with the addition of a PM and upgrade to a DL detector, which may enable its widespread adoption, including in techniques such as radiography and dynamic imaging (i.e., real-time image guidance and cone-beam CT).

Radiological equipment and accessories as sources of nosocomial infection

Background: Nosocomial infections have become a major challenge in health institutions, as they affect the quality of health care delivered. The radiology department is one of the mainstays of modern medicine. It is therefore, necessary to assess its contamination by nosocomial organisms.Aim: The study aims at identifying the nosocomial bacteria associated with imaging equipment and accessories in Aminu Kano Teaching Hospital, Kano, Nigeria.Methods: The study design was prospective and cross-sectional in nature, and was conducted between Oct 2014 to Jan 2015 using disproportionate stratified random sampling method. Four different conventional x-ray units, fluoroscopy, computed tomography, angiography and ultrasound units were selected. Swabs were collected from the surfaces of the selected parts of the equipment and accessories after working hours in each unit. The swabs were taken to the microbiology laboratory for culturing and identification using standard laboratory procedure. A total of 200 cultured samples were used in the study. The collected data was analyzed using SPSS version 16.0 software.Results: Bacteria were isolated in 43.5 % (n = 87) of all the swab samples with ultrasound transducer as major culture. Specific bacteria isolated were: Staphylococcus aureus (n = 65; 74.7 %), Pseudomonas aeruginosa (n = 14; 16.1 %), Bacillus spp (n = 6; 6.9 %), Klebsiella spp (n = 1; 1.1 %) and Proteus spp (n = 1; 1.1 %). Methylated spirit was the most effective chemical disinfectant. Conclusion: Radiology equipment and accessories in Aminu Kano Teaching Hospital are not entirely free of bacteria. Meticulous attention to disinfection will safeguard staff and other patients from nosocomial infections.

233Conventional fluoroscopy guided vs zero-fluoroscopy catheter ablation of supraventricular tachycardias

Abstract Funding Acknowledgements None Introduction Conventionally, catheter movement and placement during catheter ablation (CA) is guided by X-ray fluoroscopy. In recent years, an ‘as low as reasonably possible’ principle was established to minimize the ionizing radiation dose received by the patient and the operator. Zero-fluoroscopy approach is at the extreme end of the spectrum of this principle. With exclusion of X-ray fluoroscopy, three-dimensional electroanatomical mapping system and intracardiac echocardiography are used for catheter guidance during ablation procedures. Purpose The aim of our study was to assess and compare procedural parameters and clinical outcomes of conventional X-ray fluoroscopy guided and zero-fluoroscopy CA for treatment of supraventricular tachycardias. Methods Retrospective analysis included CA procedure between April 2014 and May 2019. Five hundred and thirteen (513) patients were selected for analysis; they had confirmed diagnosis of atrioventricular nodal reentry tachycardia (AVNRT) or atrioventricular reentry tachycardia (AVRT). Patients were divided into two groups based on the use of fluoroscopy (conventional approach group - CG; zero-fluoroscopy group - ZF). Procedural data and clinical outcomes were analyzed. Two groups were compared using chi-squared test or Mann-Whithney U test when appropriate. Results There were 249 patients (44.2% males) in CG group, and 260 patients (47.5% males) in ZF group. ZF group included 113 (43.5%) pediatric patients. The groups differed in mean age (53.4 ± 16.4 years vs 30.0 ± 19.8 years (CG vs ZF), p < 0.001), postprocedural use of antiarrhythmic agents or beta blockers (55.3% vs 17.0% (CG vs ZF), p < 0.001) and type of arrhythmia (72.3% vs 60.6% AVNRT (CG vs ZF), p = 0.003). In CG group, all procedures were performed using radiofrequency (RF) energy, whereas in ZF group, cryoablation was used in 18.3% of procedures at the discretion of the operator. Mean procedural duration was longer in CG group (100.1 ± 48.8 vs 90.4 ± 83.0 minutes, p < 0.001). The mean fluroscopy time was 13.6 ± 9.3 minutes and mean dose area product was 554.1 ± 713.6 mGycm2 in the CG group. Acute success rate was higher in CG group (95.7 vs 90.7%, p = 0.027). However, the arrhythmia-free survival rate after 13.8 ± 11.0 months of follow-up was lower in the CG group (90.9 vs 96.5%, p = 0.009). Mean number of procedures per patient was 1.04 in the CG group and 1.14 in the ZF group (p < 0.001). There were no severe complications. Conclusions Zero-fluoroscopy CA of supraventricular tachycardias is associated with lower procedural success rate, but higher long-term arrhythmia-free survival rate when compared to conventional fluoroscopy guided procedures. It is possible, that these differences are stemming from somewhat different patient populations in both groups.

Clinical research of X-ray plain film assessment of recurrence after interventional treatment of intracranial aneurysms

Objective To investigate the clinical application value of using conventional X-ray fluoroscopy follow-up after interventional treatment of intracranial aneurysms. Methods From August 2013 to June 2015, all patients with intracranial aneurysm treated with interventional therapy and followed up with digital subtraction angiography (DSA) at the Department of Neurosurgery, Wuhan General Hospital of Guangzhou Military Command were analyzed retrospectively. The patients were asked to have both immediately after procedure and reexamination operation position angiograms (all patients took conventional0°/CRAN 30°andLAO 90°/0°angiograms). A total of 86 patients with 102 aneurysms met the demands. The shadowgraphs of the microcoils were collected: the immediately after procedureoperating position, reexaminationoperation position,0°/CRAN 30°, andLAO 90°/0°shadowgraphs. The coil shape documented with the corresponding projection angle were compared in the immediately after procedure and follow-up shadowgraphs and determined whether the coil shape changed or not. Whether the aneurysms recurrence or not were identified according to the DSA result of the same case. Kappa test was used to analyze the consistency. Results In 102 aneurysms using microcoil embolization, 90 coils did not have any change. DSA examination revealed no relapse. Under X-ray fluoroscopy, the coil shape did not have any change in 3 cases, but DSA revealed aneurysm recurrence. Under X-ray fluoroscopy, the coil shape changed in 9 cases, and DSA did not reveal recurrence. Using Kappa test, both methods were highly consistent (K=0.76, P<0.05). Conclusions Observing microcoil shape with X-ray fluoroscopy can well predict whether aneurysms recurrence or not. It has better clinical application value in the follow-up after intracranial aneurysm intervention. Key words: Radiography; Intracranial aneurysm; Embolism; Follow-up studies

O-018 Magnetically Assisted Remote-controlled Endovascular Catheter for Interventional MRI: In Vitro Navigation at 1.5 T versus X-ray Fluoroscopy

PurposeTo advance the field of endovascular interventional MRI, which could allow real-time assessment of brain tissue viability during acute ischemic stroke interventions, we have developed a prototype MRI compatible magnetically...

Magnetically Assisted Remote-controlled Endovascular Catheter for Interventional MR Imaging: In Vitro Navigation at 1.5 T versus X-ray Fluoroscopy

To compare in vitro navigation of a magnetically assisted remote-controlled (MARC) catheter under real-time magnetic resonance (MR) imaging with manual navigation under MR imaging and standard x-ray guidance in endovascular catheterization procedures in an abdominal aortic phantom. The 2-mm-diameter custom clinical-grade microcatheter prototype with a solenoid coil at the distal tip was deflected with a foot pedal actuator used to deliver 300 mA of positive or negative current. Investigators navigated the catheter into branch vessels in a custom cryogel abdominal aortic phantom. This was repeated under MR imaging guidance without magnetic assistance and under conventional x-ray fluoroscopy. MR experiments were performed at 1.5 T by using a balanced steady-state free precession sequence. The mean procedure times and percentage success data were determined and analyzed with a linear mixed-effects regression analysis. The catheter was clearly visible under real-time MR imaging. One hundred ninety-two (80%) of 240 turns were successfully completed with magnetically assisted guidance versus 144 (60%) of 240 turns with nonassisted guidance (P < .001) and 119 (74%) of 160 turns with standard x-ray guidance (P = .028). Overall mean procedure time was shorter with magnetically assisted than with nonassisted guidance under MR imaging (37 seconds ± 6 [standard error of the mean] vs 55 seconds ± 3, P < .001), and time was comparable between magnetically assisted and standard x-ray guidance (37 seconds ± 6 vs 44 seconds ± 3, P = .045). When stratified by angle of branch vessel, magnetic assistance was faster than nonassisted MR guidance at turns of 45°, 60°, and 75°. In this study, a MARC catheter for endovascular navigation under real-time MR imaging guidance was developed and tested. For catheterization of branch vessels arising at large angles, magnetically assisted catheterization was faster than manual catheterization under MR imaging guidance and was comparable to standard x-ray guidance.

Angiographic C-arm CT visualization of the Woven EndoBridge Cerebral Aneurysm Embolization Device (WEB): First Experience in an Animal Aneurysm Model

Improvements in the imaging capabilities of angiographic C-arm computed tomography (CT) using flat detector angiographic (FD-CT) systems now provide a means for the in vivo visualization of devices used for the treatment of intracranial aneurysms. One such device, the WEB embolization device, is made of a braided mesh of nitinol wires, the size of which are near to the limits of visualization using conventional x-ray fluoroscopy. Our hypothesis was that the imaging of these implants C-arm CT would provide useful information regarding their positioning and deployment. In five New Zealand white rabbits elastase induced aneurysms were created and subsequently treated using a WEB. Imaging was performed using digital subtraction angiography (DSA), X-ray imaging and two different Angiographic C-arm CT protocols. The images were evaluated by two neuroradiologists using an evaluation scale. The mesh of the WEB was barely visible on the DSA or x-ray fluoroscopy images. Volume rendering technique (VRT) reconstruction and multiplanar reconstruction (MPR) of images done using the C-arm CT protocols clearly delineated the shape and structure of the device. Contrast-enhanced MPR and VRT reconstructions allowed assessment of the status of blood flow in the aneurysms. Beam hardening artifacts caused by platinum markers on the WEB were present. In vivo C-arm CT imaging of the WEB is feasible and allows precise determination of the position and deployment status of the device. On contrast-enhanced images the occlusion status of aneurysms and the positioning of the WEB in relationship to the parent artery can be evaluated. C-arm-CT may serve as a minimal-invasive follow-up imaging modality.

Calibration‐free device sizing using an inverse geometry x‐ray system

Quantitative coronary angiography (QCA) can be used to support device size selection for cardiovascular interventions. The accuracy of QCA measurements using conventional x-ray fluoroscopy depends on proper calibration using a reference object and avoiding vessel foreshortening. The authors have developed a novel interventional device sizing method using the inverse geometry scanning-beam digital x-ray (SBDX) fluoroscopy system. The proposed method can measure the diameter and length of vessel segments without imaging a reference object and when vessels appear foreshortened. SBDX creates multiple tomosynthetic x-ray images corresponding to planes through the patient volume. The structures that lie in the plane are in focus and the features above and below the plane are blurred. Three-dimensional localization of the vessel edges was performed by examining the degree of blurring at each image plane. A 3D vessel centerline was created and used to determine vessel magnification and angulation relative to the image planes. Diameter measurements were performed using a model-based method and length measurements were calculated from the 3D centerline. Phantom validation was performed by measuring the diameter and length of vessel segments with nominal diameters ranging from 0.5 to 2.8 mm and nominal lengths of 42 mm. The phantoms were imaged at a range of positions between the source and the detector (+/- 16 cm relative to isocenter) and with a range of foreshortening angles (0 degrees-75 degrees). Changes in vessel phantom position created magnifications ranging from 87% to 118% relative to isocenter magnification. Average diameter errors were less than 0.15 mm. Average length measurements were within 1% (0.3 mm) of the true length. No trends were observed between measurement accuracy and magnification. Changes in vessel phantom orientation resulted in decreased apparent length down to 28% of the original nonforeshortened length. Average diameter errors were less than 0.25 mm across all vessel angulations; errors were less than 0.1 mm for smaller diameter vessels and low to moderate vessel angles. Diameter errors increased with true diameter and vessel angle relative to the image plane. Average length measurement errors were also within 1% (0.3 mm) for each angulation. Tomosynthetic imaging with SBDX can accurately measure dimensions of vessels in various magnifications and angulations without calibration. This method may be more accurate and convenient than conventional QCA techniques.

Abstract 5283: Perfluorocarbon Microcapsules for X-ray Visualization of Mesenchymal Stem Cell Delivery and Engraftment

Mesenchymal stem cell (MSC) transplantation offers an alternative strategy for therapeutic angiogenesis for the management of ischemic cardiovascular disease. However, the poor survival of transplanted cells and lack of sustained engraftment severely limits therapeutic efficacy. We propose a novel cell microencapsulation method utilizing perfluoro-octyl-bromide (PFOB) impregnated alginate-poly-L-lysine-alginate microcapsules (PFOB Caps) that enable noninvasive cell delivery and tracking using conventional clinical X-ray fluoroscopy. Microen-capsulation of rabbit MSCs (1x10 6 cells/ml) combined with PFOB-loaded alginate was performed with an electrostatic droplet generator. Control capsules lacked PFOB. MSC viability post-encapsulation was determined using a microfluorometric assay. X-ray fluoroscopy was performed during direct intramuscular/intramyocardial injection of 2300 capsules/injection in a rabbit peripheral arterial disease (PAD) model (n=2) and a swine reperfused myocardial infarction (MI) model (n=3). Fluoroscopy and angiographic computed tomography (DynaCT) were performed to assess the ability to monitor microcapsule delivery and tracking with X-ray. As compared to control capsules, PFOB Caps showed similar swelling, when subjected to 55 mM sodium citrate incubation (mean diameter increased 5.4% for PFOB vs. 4.5% for control, P=NS), and mechanical strength (broken capsules from osmotic pressure tests: 2/591 for PFOB and 2/603 for control). The PFOB Caps showed a small viability decrease immediately after encapsulation (90±3%) with no significant further viability loss up to 4 weeks in vitro (79±5%). In both PAD and MI animals, successful injection of PFOB Caps could be demonstrated with DynaCT but not with real-time fluoroscopic images. Control capsules were never detected. CT tracking of PFOB Caps was possible up to 5 weeks post-injection. PFOB microcapsules provide an ideal microenvironment for maintaining MSC viability in vitro . In addition, PFOB proves to be a non-toxic, radiopaque agent suitable for cell tracking using conventional fluoroscopy in vivo . PFOB microencapsulation of MSCs may be a novel approach for X-ray tracking therapeutic angiogenesis.

Image-Guided Injection Therapy in the Lumbar Spine

Degenerative changes in the lumbar spine can cause back pain with or without radiation into the lower limb. The most common sufferers are middle-aged persons between the ages of 30 and 50, but the number of patients under age 30 is steadily rising. The affected persons typically have pain that can be treated initially with physical therapy and medications. When these measures no longer suffice, injection therapy can provide additional help. Published guidelines now recommend periradicular injection therapy for radicular lumbar syndromes. This low-risk, minimally invasive form of treatment should always be preferred over a surgical procedure unless major weakness is present (7, 14–16). Computerized tomography (CT) or conventional X-ray fluoroscopy is often used to provide imaging guidance for the placement of the injecting needle into the lumbar spine. Both of these techniques result in the delivery of a certain amount of ionizing radiation to the patient. The lumbar spine and the abdominal and pelvic organs lie unprotected in the path of the X-ray beam generated by the CT scanner or fluoroscope. Health care is an important area where measures should be taken to protect against radiation injury, because, on average, about 50% of an individual’s annual dose of ionizing radiation is derived from medical procedures (1, 2). The potentially problematic use of ionizing radiation in medicine is currently under discussion in a number of countries, not only in Germany (3, 11, 12), particularly in light of the increasing use of computerized tomography (17). The purpose of this article is to raise awareness of the problem of ionizing radiation in image-guided injection therapy.

Sonographische Ortung von Harnleitersteinen für die extrakorporelle Stoßwellenlithotripsie

Using the new Dornier lithotriptor MPL 9000* (multi-purpose lithotriptor) 381 treatments of urinary stones were performed from July 1988 to December 1989, 107 (28%) of them for ureteral calculi. Sonography enables stone localisation even in many cases where positioning by conventional x-ray fluoroscopy would not be possible. In 20 cases of upper ureteral stones, localization had to be performed partly by indirect measures, i.e. at the end of the dilated ureter. In 10 ureteral stones of the middle third sonographic positioning and complete disintegration was achieved. Treatment was without anaesthesia and was performed in a comfortable supine position. Therapy of 77 ureteral calculi in the caudal part--without anaesthesia--has proved extremely successful. Since it is less invasive than other measures (e.g. uretero-renoscopy or loop extraction), it is now the method of choice for the treatment of stones in the middle and lower third of the ureter.

Abstract No. 201: X-Ray Fused with Magnetic Resonance (XMR) for Accessing the Portal Vein

We evaluated the use of real-time X-ray imaging fused with MRI (XFM) to guide interventions targeting the portal vein. This technique uses MRI-derived data to provide roadmaps during conventional X-ray fluoroscopy.

Ultrasonography System Aided by Fuzzy Logic for Identifying Implant Position in Bone

We describe a new ultrasonography system, which can identify an implant position in bone. Although conventional X-ray fluoroscopy can visualize implants, it has the serious disadvantage of X-ray exposure. Therefore, we developed a system for orthopedic surgery that involves no X-ray exposure. Barriers to the development of the system were overcome using an ultrasonic instrument and fuzzy logic techniques. We located distal transverse screw holes in an intramedullary nail during surgery for femur fracture. The screw hole positions are identified by calculating two fuzzy degrees of intensity and the variance. Results allow this system to identify the screw hole positions within an error of 1.43 mm, an error ratio adequate for clinical surgical practice.

Technology preview: X‐ray fused with magnetic resonance during invasive cardiovascular procedures

We have developed and validated a system for real-time X-ray fused with magnetic resonance imaging, MRI (XFM), to guide catheter procedures with high spatial precision. Our implementation overlays roadmaps-MRI-derived soft-tissue features of interest-onto conventional X-ray fluoroscopy. We report our initial clinical experience applying XFM, using external fiducial markers, electrocardiogram (ECG)- gating, and automated real-time correction for gantry and table movement. This prospective case series for technical development was approved by the NHLBI Institutional Review Board and included 19 subjects. Multimodality external fiducial markers were affixed to patients' skin before MRI, which included contrast-enhanced, 3D T1-weighted, or breath-held and ECG-gated 2D steady state free precession imaging at 1.5T. MRI-derived roadmaps were manually segmented while patients were transferred to a calibrated X-ray fluoroscopy system. Image spaces were registered using the fiducial markers and thereafter permitted unrestricted gantry rotation, table panning, and magnification changes. Static and ECG-gated MRI data were transformed from 3D to 2D to correspond with gantry and table position and combined with live X-ray images. Clinical procedures included graft coronary arteriography, right ventricular free-wall biopsy, and iliac and femoral artery recanalization and stenting. MRI roadmaps improved operator confidence, and in the biopsy cases, outperformed the best available alternative imaging modality. Registration errors were increased when external fiducial markers were affixed to more mobile skin positions, such as over the abdomen. XFM using external fiducial markers is feasible during X-ray guided catheter treatments. Multimodality image fusion may prove a useful adjunct to invasive cardiovascular procedures.

Is Magnetic Resonance Image Guidance the Key to Opening Chronic Total Occlusions?

Through progressive plaque growth or fibrotic organization of occlusive thrombus, atherosclerosis may result in chronic total occlusion (CTO) of a major arterial conduit. If CTO develops slowly, collateral pathways may supply sufficient perfusion to retain tissue viability despite occlusion of the major inflow conduit. However, such collateral-mediated perfusion rarely matches that provided by an open main conduit, particularly during the peak demand of regional muscular activity. Although strategies to limit regional oxygen demand (eg, β-blockers for the treatment of angina pectoris) or to enhance collateral function (eg, a walking program for superficial femoral occlusion, experimental angiogenesis) may be of some benefit, these approaches generally offer less complete return of normal physiology and relief of ischemic symptoms than does direct revascularization of the occluded vessel. With surgical bypass, the nature of the occlusion (its length, duration, tortuosity, calcification) is less important than the presence of a suitable distal anastomotic target. On the other hand, with catheter-based techniques, success depends heavily on these lesion characteristics. In fact, crossing such occluded segments with a guidewire remains the dominant barrier to catheter-based treatments of occluded arterial segments. Once the guidewire has been passed successfully into the distal true lumen, the process of dilating and stenting the segment is usually straightforward and durable, at least with the use of drug-eluting stents in coronary CTOs.1,2 Article p 1101 Devices designed to cross CTOs should have 3 key features: an ability to distinguish a true luminal path from one created within (dissection) or through (perforation) the vessel wall of the occluded segment, an ability to change direction (steer) to correct deviations from the desired path through the occlusion, and an ability to penetrate the frequently fibrotic and focally calcific substance of the occlusion through the use of either mechanical stiffness or an alternative energy modality (laser, …

Magnetic Resonance Imaging–Guided Balloon Angioplasty of Coarctation of the Aorta

MRI guidance of percutaneous transluminal balloon angioplasty (PTA) of aortic coarctation (CoA) would be desirable for continuous visualization of anatomy and to eliminate x-ray exposure. The aim of this study was (1) to determine the suitability of MRI-controlled PTA using the iron oxide-based contrast medium Resovist (ferucarbotran) for catheter visualization and (2) to subsequently apply this technique in a pilot study with patients with CoA. The MRI contrast-to-noise ratio and artifact behavior of Resovist-treated balloon catheters was optimized in in vitro and animal experiments (pigs). In 5 patients, anatomy of the CoA was evaluated before and after intervention with high-resolution respiratory-navigated 3D MRI and multiphase cine MRI. Position monitoring of Resovist-treated catheters was realized with interactive real-time MRI. Aortic pressures were continuously recorded. Conventional catheterization was performed before and after MRI to confirm interventional success. During MRI, catheters filled with 25 micromol of iron particles per milliliter of Resovist produced good signal contrast between catheters and their background anatomy but no image distortion due to susceptibility artifacts. All MRI procedures were performed successfully in the patient study. There was excellent agreement between the diameters of CoA and pressure gradients as measured during MRI and conventional catheterization. In 4 patients, PTA resulted in substantial widening of the CoA and a decrease in pressure gradients. In 1 patient, PTA was ineffective. The MRI method described represents a potential alternative to conventional x-ray fluoroscopy for catheter-based treatment of patients with CoA.

MR Imaging– versus Conventional X-ray Fluoroscopy–guided Renal Angioplasty in Swine: Prospective Randomized Comparison

To test the hypothesis that the technical success rates, complication rates, and procedural times for magnetic resonance (MR) imaging-guided percutaneous transluminal angioplasty (PTA) and conventional (x-ray) fluoroscopy-guided PTA for treatment of renal artery stenosis are similar. The study was animal care and use committee approved. After surgically inducing bilateral renal artery stenosis in 11 swine, the authors performed baseline digital subtraction angiography. They transferred each animal to a 1.5-T MR imaging unit and randomly decided which artery would be treated with MR-guided PTA. With MR imaging guidance, angioplastic devices were tracked by using active and passive techniques. Vascular depiction was achieved by using catheter-directed MR angiography. Stenotic vessels were dilated by using 5-6-mm-diameter balloon catheters. PTA was then performed in the contralateral artery by using conventional fluoroscopy-guided techniques. With the intention to treat, the authors compared the technical success (residual stenosis < 50%) rates, complication rates, and procedural times for each guidance method. They compared technical successes and complications by using the McNemar test and procedural times by using a paired t test, with P < .05 indicating a significant difference. The authors successfully dilated nine (82%) of 11 renal arteries with MR guidance and all 11 arteries (100%) with conventional fluoroscopic guidance. The difference was not significant (P = .5). Complications occurred in three (27%) arteries with MR guidance and in one (9%) artery with fluoroscopic guidance, with no significant differences (P = .5). The mean MR-guided PTA procedural time was 46 minutes longer than the fluoroscopy-guided PTA procedural time; this difference was significant (P = .01). In a small cohort of swine, the authors did not observe a significant difference between MR imaging- and conventional fluoroscopy-guided renal artery PTA in terms of success and complication rates. However, no evidence of similarity between the techniques should be assumed. Procedural times differed significantly.

Intrabody three-dimensional position sensor for an ultrasound endoscope.

To avoid or reduce the X-ray exposure in endoscopic examinations and therapy, as an alternative to the conventional two-dimensional X-ray fluoroscopy we are developing an intrabody navigation system that can directly measure and visualize the three-dimensional (3-D) position of the tip and the trace of an ultrasound endoscope. The proposed system can identify the 3-D location and direction of the endoscope probe inserted into the body to furnish endoscopic images. A marker transducer(s) placed on the surface of the body transmits ultrasound pulses, which are visualized as a marker synchronized to the scanning of the endoscope. The position (direction and distance of the marker transducer(s) outside the body relative to the scanning probe inside the body) of the marker is detected and measured in the scanned image of the ultrasound endoscope. Further, an optical localizer locates the marker transducer(s) with six degrees of freedom. Thus, the proposed method performs inside-body 3-D localization by utilizing the inherent image reconstruction function of the ultrasound endoscope, and is able to be used with currently available commercial ultrasound image scanners. The system may be envisaged as a kind of global positioning system for intrabody navigation.

Techniques of renal angioplasty.

HomeRadiologyVol. 161, No. 3 Next Techniques of renal angioplasty.C J Tegtmeyer, T A SosC J Tegtmeyer, T A SosC J TegtmeyerT A SosPublished Online:Dec 1 1986https://doi.org/10.1148/radiology.161.3.2947260MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In Article HistoryPublished in print: 1986 FiguresReferencesRelatedDetailsCited ByAssessment of the Vessel Lumen Diameter and Degree of Stenosis in the Superficial Femoral Artery before Intervention: Comparison of Different AlgorithmsJournal of Vascular and Interventional Radiology, Vol. 20, No. 2CardioVascular and Interventional Radiology, Vol. 32, No. 1Gefässchirurgie, Vol. 14, No. 3Nephrology, Vol. 4, No. 1-2Vascular and Endovascular Surgery, Vol. 41, No. 6MR Imaging– versus Conventional X-ray Fluoroscopy–guided Renal Angioplasty in Swine: Prospective Randomized Comparison1Reed A. Omary, , James A. Gehl, , Brian E. Schirf, , Jordin D. Green, , Biao Lu, , F. Scott Pereles, , Jie Huang, , Andrew C. Larson, , and Debiao Li, 1 February 2006 | Radiology, Vol. 238, No. 2EJVES Extra, Vol. 12, No. 4Quand, comment et pourquoi réaliser une exploration des artères rénales ?Journal de Radiologie, Vol. 85, No. 6Current Treatment Options in Cardiovascular Medicine, Vol. 5, No. 2Journal of Vascular and Interventional Radiology, Vol. 14, No. 11Journal of Hypertension, Vol. 19, No. 8American Journal of Roentgenology, Vol. 177, No. 6Clinical Cardiology, Vol. 23, No. 6Journal of Vascular and Interventional Radiology, Vol. 11, No. 3Journal of Vascular and Interventional Radiology, Vol. 11, No. 3Catheterization and Cardiovascular Interventions, Vol. 47, No. 2The Lancet, Vol. 353, No. 9149International Journal of Cardiology, Vol. 66Journal of Vascular and Interventional Radiology, Vol. 9, No. 1Sao Paulo Medical Journal, Vol. 116, No. 1Kidney International, Vol. 53, No. 6CardioVascular and Interventional Radiology, Vol. 20, No. 3New England Journal of Medicine, Vol. 336, No. 7Pediatrics, Vol. 99, No. 1Catheterization and Cardiovascular Diagnosis, Vol. 37, No. 3Journal of Vascular and Interventional Radiology, Vol. 7, No. 4Mayo Clinic Proceedings, Vol. 70, No. 11Urologic Clinics of North America, Vol. 21, No. 2Journal of Vascular and Interventional Radiology, Vol. 5, No. 2Journal of Vascular and Interventional Radiology, Vol. 5, No. 6Cardiovascular and Interventional Radiology, Vol. 16, No. 3American Heart Journal, Vol. 125, No. 5Journal of Vascular and Interventional Radiology, Vol. 4, No. 4Acta Radiologica, Vol. 34, No. 2Acta Radiologica, Vol. 34, No. 5Heart and Vessels, Vol. 7, No. S1Angiology, Vol. 42, No. 1Cardiovascular and Interventional Radiology, Vol. 13, No. 1Cardiovascular and Interventional Radiology, Vol. 13, No. 2Clinical Radiology, Vol. 42, No. 5World Journal of Urology, Vol. 7, No. 2Seminars in Nuclear Medicine, Vol. 19, No. 2Acta Radiologica, Vol. 30, No. 2CardioVascular and Interventional Radiology, Vol. 11, No. 2Current Problems in Diagnostic Radiology, Vol. 16, No. 2Recommended Articles RSNA Education Exhibits RSNA Case Collection Vol. 161, No. 3 Metrics Altmetric Score PDF download