Abstract:
RATIONALE AND OBJECTIVES:To test noninvasive inductive heating of implanted vascular stents as an alternative approach for reduction or prevention of neointimal hyperplasia. METHODS:Calorimetric pretests were performed to get an orientation on the different parameters of influence for inductive heating of stents. The field strength was set to a maximum of 90 kA/m within a frequency range from 80 kHz to 320 kHz. The electromagnetic field was emitted by a custom-made water-cooled copper winding antenna. A flow model for stent heating was set up to assess the increase in temperature of an expanded 316L stainless steel stent with typical coronary stent dimensions of 3.5 mm diameter and 14.5 mm in length, and in a second setup with 4.5 mm diameter and 13 mm in length, respectively. The stent was located in a bioartificial artery, simulated by a fibrinogen matrix with a defined number of vital cells. The system was exposed to a pulsating perfusion and to an electromagnetic field of 200 kHz over a period of 20 minutes and in a second setup to an electromagnetic field of 300 kHz and increasing intensity up to maximum power-output. Afterward, the artificial vessel was sliced and examined by fluorescence microscopy to evaluate the number and location of damaged cells. RESULTS:The calorimetric tests show an exponential correlation of energy uptake in the stent with an increase in frequency and a constant generator output. At a frequency of 80 kHz, the power uptake accounts for 0.1 W (250 kHz 1.0 W; 320 kHz 1.9 W, respectively). The flow tests confirmed feasibility to elevate the stent temperature from 37 degrees C body temperature to 44 degrees C at 200 kHz within 55 seconds. The temperature increase of the fluid passing the heated vessel region was only marginal (maximum of 0.5 degrees C). Cell necrosis after 20 minutes of treatment was not observed. In a second set-up with 4.5 mm stent diameter, a frequency of 300 kHz and with maximum power output, the stent temperature was increased to 80 degrees C and there was extensive necrosis area around the stent. Treatment time and stent temperature were optimized in further tests. CONCLUSION:Selective noninvasive energy transfer to coronary stainless steel stents by inductive heating is possible within a wide range of power. By thermal conduction, vital cells close to the stent struts can be affected. The frequency of 200 kHz turned out to be favorable. There is still room for further optimization of energy dosage with regard to material and stent design, to induce controlled cell death. The method has potential to serve as an alternative approach for prevention of instent restenosis.
journal_name
Invest Radioljournal_title
Investigative radiologyauthors
Floren MG,Günther RW,Schmitz-Rode Tdoi
10.1097/01.rli.0000117881.42422.72keywords:
subject
Has Abstractpub_date
2004-05-01 00:00:00pages
264-70issue
5eissn
0020-9996issn
1536-0210pii
00004424-200405000-00004journal_volume
39pub_type
杂志文章abstract:RATIONALE AND OBJECTIVES:The authors compare the magnetic resonance (MR) phase contrast flow velocity measurements in varying concentric stenoses with invasive measurements obtained with a Doppler guidewire. METHODS:Flow velocity measurements were obtained using a calibrated 0.018 inch 12 MHz Doppler guidewire and a 1...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-199808000-00001
更新日期:1998-08-01 00:00:00
abstract::Radiation dose in computed tomography (CT) has become a hot topic due to an upward trend in the number of CT procedures worldwide and the relatively high doses associated with these procedures. The main aim of this review article is to provide an overview of the most frequently used metrics for CT radiation dose chara...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0000000000000727
更新日期:2021-01-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:The authors evaluate the use of magnetic resonance (MR) to image pulmonary perfusion in healthy controls and to detect pulmonary defects in patients with unilateral lung transplantation, using dynamic images after contrast administration. METHODS:Five patients with right lung transplantation a...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-199706000-00006
更新日期:1997-06-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:The authors differentiate breast lesions on sonography by measurements in two compression states that are perpendicular to each other. METHODS:Diameters of 100 breast lesions were measured preoperatively under lateromedial and craniocaudal compression with a new sonographic method. This method...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-199607000-00003
更新日期:1996-07-01 00:00:00
abstract::We evaluated the density distribution (anterior-posterior) of the right lung in 19 acutely anesthetized supine dogs using computed transmission tomography (CTT). Eleven dogs served as controls, and eight received 0.12 cc/kg of intravenously administered oleic acid. The latter were sequentially imaged over 1 hour. Nine...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:
更新日期:1984-05-01 00:00:00
abstract::French physicians must obtain their patient's consent before carrying out an action that interferes with the patient's corporal integrity. The doctor must use simple, approximate, intelligent, and honest words that help the patient to reach the indispensable decision. Proof of lack of consent lies with the patient. Th...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-198809001-00006
更新日期:1988-09-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:To evaluate different vein graft-coated stent systems in the endovascular treatment of experimental arteriovenous fistulae (AVF) in a canine model. METHODS:Bilateral carotid-to-external jugular vein AVF were created. Two balloon-expandable tantalum stents (Strecker stent), two self-expanding n...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-199901000-00004
更新日期:1999-01-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:The authors studied the incidence and distribution of orthopedic injuries sustained in Operation Desert Shield and Desert Storm by evaluating whether existing diagnostic imaging modalities were sufficient to diagnose the types of musculoskeletal injuries incurred. The authors also sought to det...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-199703000-00006
更新日期:1997-03-01 00:00:00
abstract::The absorbed levels of ethanol or tetracycline, used as gallbladder sclerosing agents, were measured in the systemic blood circulation of 16 rabbits. The maximal systemic level of ethanol was 46 mg/dl and of tetracycline was 4.6 micrograms/ml after 30 minutes of gallbladder exposure. Comparable serum levels would be c...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-198605000-00005
更新日期:1986-05-01 00:00:00
abstract:OBJECTIVES:The objectives of this study were to test the feasibility of an investigational dual-channel next-generation endorectal coil (NG-ERC) in vivo, to quantitatively assess signal-to-noise ratio (SNR), and to get an impression of image quality compared with the current clinically available single-loop endorectal ...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0b013e3182a56678
更新日期:2014-01-01 00:00:00
abstract::The retropsoas recess, a previously undescribed normal anatomic variant, is reported. In most individuals, the space posterior to the belly of the psoas muscle contains fat within the posterior pararenal space. However, a retrospective review of 250 consecutive CT examinations of the abdomen revealed 11 cases (4.4%) i...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-198707000-00004
更新日期:1987-07-01 00:00:00
abstract::Gelatin encapsulated nitrogen microbubbles were effective ultrasonic contrast agents in in vitro phantom and in vivo rabbit V2 carcinoma studies. Intra-arterial injection of 80-micrometer gelatin encapsulated nitrogen microbubbles appeared to improve tumor visualization by rim enhancement, which persisted for several ...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-198005000-00013
更新日期:1980-05-01 00:00:00
abstract::In vivo and in vitro studies have shown that areas of myocardial infarctions can be delineated on CT scans after intravenous administration of iodinated contrast material to dogs with experimental myocardial infarctions. Within the first minute after intravenous administration of contrast material (initial myocardial ...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-198011001-00039
更新日期:1980-11-01 00:00:00
abstract::The magnitude and time course of contrast enhancement in spontaneous canine brain tumors was determined for two contrast agents: meglumine iothalamate and sodium meglumine ioxaglate. Tumor enhancement during contrast infusion and at 5, 10, 15, 30 and 45 minutes was measured using quantitative computed tomography. Bloo...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-198411001-00007
更新日期:1984-11-01 00:00:00
abstract::Using simple surgical techniques, experimental carotid aneurysms are created which simulate some types of human berry aneurysms, both in hemodynamic and radiographic behavior. End to side anastomoses of an external jugular vein graft to the common carotid artery can be carried out by radiologic personnel with no forma...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-197703000-00009
更新日期:1977-03-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:Diabetic patients frequently suffer contrast media-induced nephropathy. Hyperglycemia in diabetes mellitus causes gradual deterioration of glomerular mesangial cells (MCs) in the kidney. In this study, the authors investigated the response of rat MCs cultured in high-glucose medium to diatrizoa...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-200107000-00001
更新日期:2001-07-01 00:00:00
abstract:OBJECTIVES:The aim of this study was to investigate blood pressure dependency of ultrasound time-harmonic elastography (THE) for quantification of aortic stiffness. MATERIALS AND METHODS:Thoracoabdominal aortas were surgically removed from 9 healthy domestic pigs and prepared for elastographic experiments. All vessels...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0000000000000618
更新日期:2020-03-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:Gd-DTPA is a well-characterized, safe contrast agent frequently used in magnetic resonance imaging (MRI) of the central nervous system. The purpose of this double-blind, comparative MRI study of brain, spine, trunk, and limbs was to evaluate the safety and efficacy of Gd-DOTA versus Gd-DTPA in ...
journal_title:Investigative radiology
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1097/00004424-199502000-00002
更新日期:1995-02-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:The vascular opacification characteristics of a new nonionic, dimeric contrast agent, iodixanol, have been compared with a nonionic, monomeric agent, iohexol, using ultrafast computed tomography (UFCT). METHODS:In 10 experiments with mongrel dogs, the contrast agents were alternately injected ...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-199212000-00011
更新日期:1992-12-01 00:00:00
abstract:OBJECTIVES:The objective of this study was to evaluate the use of dielectric pads for improving high spatial resolution imaging of the inner ear at 7 T. MATERIALS AND METHODS:Two sets of dielectric pads were designed using electromagnetic simulations and implemented using a deuterated suspension of barium titanate. Th...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0000000000000026
更新日期:2014-05-01 00:00:00
abstract:OBJECTIVES:Pancreatic ductal adenocarcinoma (PDAC) is a very aggressive tumor with a very low 5-year survival rate of 8%. The aims of this study are to determine reference values and physiologic confounders in healthy pancreas and to assess the diagnostic accuracy of ultrasound time-harmonic elastography (THE) in the d...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0000000000000638
更新日期:2020-05-01 00:00:00
abstract::The effects of an intravenously administered nitroxyl spin label (PCA) on the magnetic resonance imaging (MRI) appearance and relaxation times of acute canine myocardial infarctions were studied. Twenty-four hours after ligation of the left anterior descending coronary artery (LAD), animals were either sacrificed imme...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:
更新日期:1985-09-01 00:00:00
abstract:PURPOSE:The aim of this study was to compare qualitative and quantitative image quality and geometric distortion of 4 magnetic resonance diffusion-weighted imaging (DWI) sequences of the prostate using comparable imaging parameters and similar acquisition times. METHODS AND MATERIALS:Axial T2-weighted turbo spin echo ...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0000000000000429
更新日期:2018-04-01 00:00:00
abstract:OBJECTIVE:The aim of this study was to optimize computed tomography (CT) surveillance of skeletal metastases in patients with breast cancer through the use of osseous subtraction maps between baseline and follow-up examinations created by a novel software algorithm. The new postprocessing algorithm segments the origina...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0000000000000343
更新日期:2017-02-01 00:00:00
abstract:UNLABELLED:Szapiro D, Ghaye B, Willems V, et al. Evaluation of CT time-density curves of lower-limb veins. Invest Radiol 2001;36:164-169. RATIONALE AND OBJECTIVES:To evaluate time-density curves of the lower-limb veins for optimization of CT venography. METHODS:Fifty patients referred for chest CT were randomized int...
journal_title:Investigative radiology
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1097/00004424-200103000-00005
更新日期:2001-03-01 00:00:00
abstract:OBJECTIVE:Dynamic ventilation (3)He-MRI is a new method to assess pulmonary gas inflow. As differing airway diameters throughout the ventilatory cycle can influence gas inflow this study intends to investigate the influence of volume and timing of a He gas bolus with respect to the beginning of the tidal volume on insp...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0b013e3181690111
更新日期:2008-06-01 00:00:00
abstract:PURPOSE:The aim of this study was to develop a method to delineate the lethally frozen-tissue region (temperature less than -40°C) arising from interventional cryoablation procedures using a short tau inversion-recovery ultrashort echo-time (STIR-UTE) magnetic resonance (MR) imaging sequence. This method could serve as...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0000000000000642
更新日期:2020-05-01 00:00:00
abstract:OBJECTIVE:This study aims for targeted biopsy validation of magnetic resonance fingerprinting (MRF) and diffusion mapping for characterizing peripheral zone (PZ) prostate cancer and noncancers. MATERIALS AND METHODS:One hundred four PZ lesions in 85 patients who underwent magnetic resonance imaging were retrospectivel...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0000000000000569
更新日期:2019-08-01 00:00:00
abstract:OBJECTIVE:The objective of this study was to determine the gadolinium (Gd) concentration remaining in human bone tissue after administration of standard clinical doses of 2 Gd-based contrast agents: ProHance and Omniscan. MATERIALS AND METHODS:After administration of 0.1 mmol/kg of Gd chelate to patients undergoing hi...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/01.rli.0000186569.32408.95
更新日期:2006-03-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:The capability of an indirect computed tomographic lymphography (CT-LG) using a nonionic monometric contrast medium iopamidol for visualizing breast lymphatic pathways was preliminarily tested. MATERIALS AND METHODS:In 10 female dogs, a total of 0.5 and 1 mL of undiluted iopamidol was injected...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-200302000-00002
更新日期:2003-02-01 00:00:00