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PubMed1994

Observing radiation safety practices in GI nursing.

During the past 2 years, the staff in the Endoscopy Department at Georgetown University Hospital noticed an increase in the number of procedures being performed in the x-ray department. The nursing staff were becoming concerned with the amount of x-ray exposure they were receiving. The purpose of this article is to describe the process in which the nursing staff are equally rotated through radiology based on a daily log of fluoroscopy exposure for each nurse. At the completion of each x-ray procedure, the nurses chart the amount of x-ray and fluoroscopy exposure. Each nurse wears a total body film badge while a second badge is worn at the collar. Monthly dosimetry reports are made available for each nurse to review. After 1 year of monitoring by this method, it was found that fluoroscopy exposure was evenly distributed to each nurse.

Academic Medical Centers↗
PubMed1988

Complete hemidiaphragmatic paralysis in a patient with multiple sclerosis.

We present a case history of a patient with definite multiple sclerosis who developed an abrupt onset of unilateral diaphragmatic paralysis, minor increase in lower extremity spasticity and complaint of marked neck stiffness. Her vital capacity during this episode was 600 mL and she was in impending respiratory failure. The diaphragmatic paralysis was demonstrated by radiographic plain films and fluoroscopy. Phrenic nerve stimulation was performed during fluoroscopy and the evoked motor response from the diaphragm recorded. There was a normal amplitude diaphragmatic twitch observed with an evoked motor response latency of 1 ms and amplitude of 300 microV. After high dose intravenous steroids, her neck stiffness and spasticity improved, her vital capacity improved to 1500 mL and her diaphragm regained its normal position and movement confirmed by followup radiographic plain films and fluoroscopy. We postulate the presence of a demyelinating plaque in the brainstem fibers descending to the phrenic nucleus as the etiology of the diaphragmatic paralysis. We are unaware of any other case reports of unilateral "upper motor neuron" phrenic nerve paralysis secondary to multiple sclerosis.

Adult↗
PubMed1996

Percutaneous transpedicular biopsy of vertebral body lesions.

STUDY DESIGN: This prospective study evaluates the use of transpedicular biopsy in obtaining diagnostic tissue from vertebral body lesions. OBJECTIVE: To report the authors' experience of all (N = 32) percutaneous transpedicular biopsies performed between 1990-1994. SUMMARY OF BACKGROUND DATA: Previous articles have discussed the value of open biopsy of the vertebral body using a Craig needle. A large series of closed percutaneous transpedicular biopsies have not been reported. METHODS: The authors evaluated 32 patients (26 outpatients, six inpatients) who underwent transpedicular biopsy for T1-L4 lesions of the vertebral bodies. None of the tumors had an extraosseous component. Biopsy specimens were obtained from 25 lesions using C-arm fluoroscopy; seven were guided by computed tomography. All biopsies were performed with a 14- to 17-gauge bone biopsy needle. RESULTS: The needle passed through the pedicle into the site of disease in all patients, as confirmed by C-arm fluoroscopy or computed tomography. There were 22 malignancies; four isolated compression fractures, two at T6, one at T7, one at T8; four cases of infection or inflammation; and one case each of Paget's disease and myelofibrosis. Two patients required a second biopsy because the tissue sample was suspicious for lymphoma but not diagnostic. All 26 outpatients were discharged after a 2-hour observation period. There were no complications. CONCLUSION: Transpedicular biopsy of deep vertebral body lesions using a bone biopsy needle under computed tomography or fluoroscopy guidance can be performed safely and efficaciously as an outpatient procedure.

Adult↗
PubMedDate not supplied

Computer-assisted cannulated screw fixation for slipped capital femoral epiphysis.

In slipped capital femoral epiphysis (SCFE), cannulated screw fixation is a standard procedure. The aim of this study was to investigate the feasibility of a fluoroscopy-supported navigation system for screw fixation in SCFE. Using a fluoroscopy-enhanced navigation system, a cannulated screw fixation was performed in seven hips of four patients. The navigation system showed a high feasibility in instrument visualization and implant placing. The mean x-ray time was 6.2 seconds. Initial experiences are very promising and show advantages of the fluoroscopy-supported navigation. Considerably reduced x-ray exposure for patients and surgeons is possible. In the future, further efforts will be necessary to develop navigation-specific instruments to enhance the precision of screw positioning.

Adolescent↗
PubMed1990

Cath-Finder Catheter Tracking System: a new device for positioning of central venous catheters. Early experience from implantation of brachial portal systems.

To simplify the implantation procedure of a new brachially implantable venous access system (P.A.S. Port. Pharmacia Deltec Inc., St. Paul, MN, USA), the Cath-Finder Catheter Tracking System (Pharmacia Deltec) was evaluated. The Cath-Finder senses the catheter tip position by utilizing a preconnected sensor wire (guidewire) within a catheter to detect an electromagnetic signal transmitted through the body tissue from a locator wand positioned over an appropriate external landmark. The aim of the study was to evaluate the accuracy of the Cath-Finder (compared to fluoroscopy) in determining the catheter tip position peroperatively during implantation of P.A.S. Port systems in patients with malignant diseases. The accuracy of the Cath-Finder in assessing the position of the catheter tip was registered in 16 implantation procedures. The tip positions determined with the Cath-Finder (when projected on the skin) correlated well to fluoroscopy (within 1 cm in eleven patients, 2-3 cm in four patients, and 4 cm in one patient). By using the right 3rd rib parasternally as an external landmark for the locator wand, the Cath-Finder Catheter Tracking System appears to be an alternative to fluoroscopy peroperatively for accurate placement of central venous catheters in the superior vena cava. However, a postoperative confirmatory x-ray control is recommended until further experience of the system is available.

Adolescent↗
PubMed1981

The use of the balloon-tipped floating catheter in temporary transvenous cardiac pacing.

The effectiveness and safety of balloon-tipped, flow guided, electrodes for ventricular pacing as opposed to the fluoroscopy-guided semi-rigid bipolar electrodes have never been compared in a controlled study. A prospective study was therefore undertaken to compare both techniques in semi-elective and emergency procedures. Flow guided electrodes were inserted in 67 patients (group A) and semi-rigid electrodes in 44 patients (group B). The results of group A were judged to be superior to those of group B in four aspects: a) shorter time (6'45" vs. 13'30", p less than 0.0005); b) lower incidence of catheter displacement (13.4 vs. 32.0 percent, p less than 0.05); c) longer interval of time between implantation and catheter displacement (4.4 vs. 1.9 days, p less than 0.0005); d) lower incidence of serious ventricular arrhythmias during insertion (1.5 vs. 20.4 percent, p less than 0.005). Threshold at insertion was not significantly different (0.6 +/- 0.3 vs 0.7 +/- 0.2 milliampere). The superiority of flow-guided electrodes over fluoroscopy-guided electrodes persisted in the comparison of semielective insertions in groups A and B. We conclude that the flow-guided insertion technique is safer, more expeditious and more stable than the fluoroscopy-guided technique in semi-elective as well as in emergency insertions.

Adolescent↗
PubMed1993

Single physician approach to radiofrequency catheter ablation in patients with supraventricular tachycardia.

The minimal requirements for safe and effective performance of catheter ablation using radiofrequency current are still unclear. To determine the feasibility and safety of single physician approach to catheter ablation of supraventricular tachycardia substrate using radiofrequency energy, the results of the ablation procedure in 52 consecutive patients were evaluated. The procedures were performed during 1 year by the same physician and nurse. Twenty-one patients had selective atrioventricular (AV) nodal pathway ablation and 31 patients had accessory AV pathway ablation. Forty-eight patients (89%) had the diagnostic and the ablative procedure during the same electrophysiological test. In the 21 patients with AV nodal reentrant tachycardia, all had successful selective ablation of the fast (13) or the slow (8) pathways. Eight patients had recurrence of the clinical tachycardia and had a successful reablation. No patient developed complete AV block or other significant complications. The mean fluoroscopy time during the procedure was 16.0 +/- 8.6 minutes. In the eight patients with Wolff-Parkinson-White syndrome, all concealed accessory pathways were successfully ablated with a mean fluoroscopy time of 30.0 +/- 27.9 minutes. Two patients had recurrence of the conduction through the accessory pathway and had a successful reablation. Eighteen of 19 patients with a single overt accessory pathway had successful ablation, with a fluoroscopy time of 22.7 +/- 20.6 minutes. Three patients had an early recurrence of the conduction through the accessory pathway, reablation was successful in two of them. Ten accessory pathways were ablated in four patients with multiple pathways during nine procedures. Only two patients developed minor peripheral vascular complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2004

Radiofrequency ablation of atrial flutter: a randomized controlled study of two anatomic approaches.

Atrial flutter often results from a macroreentrant circuit that uses anatomic structures within the right atrium as its borders. RF ablation at the site of an obligatory isthmus can eliminate the atrial flutter circuit. The aim of this study was to compare two approaches to atrial flutter ablation: the septal (septal aspect of the tricuspid valve annulus to coronary sinus ostium and Eustachian ridge) approach versus the posterior (inferior vena cava to tricuspid valve annulus) approach. Twenty patients were randomized to either the "septal" or "posterior" approach. Entrainment mapping and/or confirmation of bidirectional isthmus conduction at baseline were performed in those patients in atrial flutter and normal sinus rhythm, respectively. RF ablation was performed with standard catheters and techniques. Crossover was permitted after two lines of RF lesions. Endpoints included acute success rates and fluoroscopy times. There was no statistically significant difference in the success rate between the two approaches using intention-to-treat analysis. Fluoroscopy times in the septal versus posterior approaches were 58.4 +/- 30.3 versus 70.8 +/- 31.1 minutes, respectively (P = 0.7). There was more frequent crossover in patients assigned to the septal approach and the one major complication, atrioventricular block, also occurred using this approach. There was no statistically significant difference in the success rate or fluoroscopy times between the septal and posterior approaches to atrial flutter ablation. However, given the risk of atrioventricular block with the septal approach, the posterior approach should be the preferred initial choice.

Atrial Flutter↗
PubMed2001

Esophageal pH monitoring: are you sure that the electrode is properly placed?

OBJECTIVE: A crucial methodological aspect of ambulatory 24-h esophageal pH monitoring is electrode placement. Lower esophageal sphincter (LES) location is recommended for standard electrode positioning. The aim of the present study was to evaluate prospectively whether LES manometric location and intragastric pH acid confirmation suffice to guarantee that the pH electrode is properly placed. METHODS: We evaluated data from 402 consecutive patients undergoing esophageal pH monitoring. LES location was determined by manometry, and the pH electrode was introduced until a pH recording <3 was obtained. Subsequently, it was positioned 5 cm above the proximal LES border. Thereafter, adequate catheter placement and absence of bends or loops were checked by fluoroscopy. Patients with bent or rolled catheters were instructed to have breakfast immediately, and catheter placement was checked again by fluoroscopy. RESULTS: When checked by fluoroscopy, the catheter was properly placed in 383 patients (95.3%). In the other 19 (4.7%), it was not located in the distal part of the esophagus owing to bending or rolling: 14 in the esophagus and five in the pharynx. After breakfast, 14 of the 19 malpositioned catheters were properly positioned whereas five remained bent or rolled. Those bent in the esophagus were more prone to unbending (12 of 14) than those bent or rolled in the pharynx (two of five). CONCLUSIONS: After LES location by manometry and demonstration of acid pH during the pH step-up technique, the pH electrode was properly placed in more than 95% of cases. Nevertheless, it cannot be completely guaranteed that the pH catheter will not bend or roll, and the pH electrode will not be malpositioned. Eating immediately after electrode placement resolves this problem in the majority (75%) of cases. Therefore, we recommend that patients undergoing esophageal pH-metric studies be instructed to eat as soon as possible after electrode placement to minimize these possible pitfalls.

Adolescent↗
PubMed1995

Multiple brushings with immediate Riu's stain via flexible fibreoptic bronchoscopy without fluoroscopic guidance in the diagnosis of peripheral pulmonary tumours.

BACKGROUND: Accurate diagnosis of peripheral pulmonary lesions usually relies on fluoroscopic guided procedures. As fluoroscopy is not routinely available in many respiratory units, an approach not using fluoroscopy but with a high diagnostic yield is highly desirable. METHODS: Immediate cytological examination of multiple brushings using Riu's stain, a modified Wright's stain, was performed in 38 patients with peripheral pulmonary lesions not visible at bronchoscopy. The results were compared with the final diagnoses determined by histological examination or subsequent Papanicolaou staining of cytological specimens and clinical course. RESULTS: Of the 38 patients 29 were subsequently confirmed to have a malignant tumour. Our method provided a diagnosis of malignancy in 86% of these lesions. The accuracy (91%) and sensitivity (88%) were higher for lesions > 3 cm in diameter than for those of diameter < or = 3 cm (87% and 83%). There were no false positive results. The 29 lesions correctly diagnosed as malignant by Riu's stain required significantly fewer brushings (mean (SD) 3 (2)) than the nine benign lesions (5 (4)). CONCLUSIONS: This technique provides a high diagnostic yield, avoids the need for fluoroscopy, and is probably safer than percutaneous biopsy.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed2003

Magnetic resonance--guided cardiac catheterization in a swine model of atrial septal defect.

BACKGROUND: Radiation exposure during cardiac catheterization, limited image planes, and poor soft tissue definition are disadvantages of x-ray fluoroscopy that could be overcome with the use of MRI. This study evaluates the feasibility of real-time MRI (MR fluoroscopy) to guide left and right heart catheterization. METHODS AND RESULTS: Anesthetized pigs (n=7) with defects of the atrial septum were catheterized using venous and arterial access. A prototype active tracking catheter was used to obtain blood pressures and samples from cardiac chambers and great vessels using antegrade, transseptal, and retrograde approaches. MR fluoroscopy was used for catheter steering. Velocity-encoded cine MRI was used to measure pulmonary and aortic blood flow to calculate vascular resistances. Image planes used during catheter manipulation used rapid sequencing to planes directed by the operator to include the tip of the catheter and the chamber to be entered. All areas of interest were effectively entered, and samples were obtained. In the presence of an acute atrial septal defect, a Qp/Qs ratio of 1.3+/-0.2 was measured, and no significant differences in pressure between inferior vena cava, right atrium, and left atrium were found. Pulmonary and aortic flow were 4.9+/-0.6 and 3.7+/-0.4 L/min, and pulmonary and systemic vascular resistance were 312+/-134 and 2006+/-336 dyne x s x cm(-5). CONCLUSIONS: Left and right heart catheterization using MR guidance is feasible. The combination of hemodynamic catheterization data with anatomic and functional MRI may significantly improve the evaluation of patients with congenital heart disease while avoiding radiation exposure.

Animals↗
PubMed1997

Monitoring considerations for port-access cardiac surgery.

BACKGROUND: A method for monitoring patients was evaluated in a clinical trial of minimally invasive port-access cardiac surgery with closed chest endovascular cardiopulmonary bypass. METHODS AND RESULTS: Cardiopulmonary bypass was conducted in 25 patients through femoral cannulas. An endovascular pulmonary artery vent was placed in the main pulmonary artery through a jugular vein. For mitral valve surgery, a catheter was placed in the coronary sinus for delivery of cardioplegia. A balloon catheter ("endoaortic clamp," EAC) used for occlusion of the ascending aorta, delivery of cardioplegia, aortic root venting, and pressure measurement was inserted through a femoral artery and initially positioned by use of fluoroscopy and transesophageal echocardiography (TEE). Potential migration of the EAC was monitored by (1) TEE of the ascending aorta, (2) pulsed-wave Doppler of the right carotid artery, (3) balloon pressure, (4) comparison of aortic root pressure and right radial artery pressure, and (5) fluoroscopy. TEE, fluoroscopy, and pressure measurement were effective in monitoring catheter insertion and position. With inadequate balloon inflation, migration of the EAC toward the aortic valve could be detected with TEE. During administration of cardioplegia, TEE showed movement of the balloon away from the aortic valve, and migration into the aortic arch was detectable with loss of carotid Doppler flow. Stability of EAC position was demonstrated with appropriate balloon volume. Cardioplegic solution was visualized in the aortic root, and aortic root pressure changed appropriately during administration of cardioplegia. Venous cannula position was optimized with TEE and endopulmonary vent flow measurement. CONCLUSIONS: An effective method has been developed for monitoring patients and the catheter system during port-access cardiac surgery.

Cardiopulmonary Bypass↗
PubMed2004

Intramedullary screw fixation of the fifth metatarsal: an anatomic study and improved technique.

Intramedullary screw fixation has been found to be a reliable treatment for certain fractures of the fifth metatarsal. Techniques for this treatment have been described relying largely on intraoperative fluoroscopy. Ten human cadaver specimens had their fifth metatarsals osteotomized and underwent retrograde intramedullary pin placement. Anatomic landmarks and the location of the sural nerve in relation to this starting point were measured. The trajectory of a pin reducing the osteotomy was analyzed. Using the resultant starting point and guide pin trajectory, intramedullary screw placement was performed reliably without the aid of fluoroscopy. This study demonstrates that intramedullary screw fixation of proximal fifth metatarsal fractures may be performed with the use of anatomic landmarks, which decreases the amount of intraoperative fluoroscopy needed.

Bone Screws↗
PubMedDate not supplied

Accuracy of implanted port placement with the use of the electromagnetic CathTrack catheter locator system.

PURPOSE: To test whether an electromagnetic guidance system such as CathTrack would allow long-term central venous access devices to be reliably placed at a decreased cost and without radiation exposure to patients and staff. The following study was undertaken to verify accuracy of the CathTrack system for catheter placement and to develop guidelines for its use. METHODS: Twenty-nine consecutive patients were prospectively enrolled in the study and taken to the operating room for implantation of a permanent central venous access port. By protocol, the CathTrack system was used to guide initial catheter positioning using the center of the third intercostal space along the right sternal border as the desired external target. Fluoroscopy was then used to visualize tip position and relocate the catheter tip to the exact position desired by the surgeon. RESULTS: Catheter placement using the CathTrack system was successfully accomplished in 27 out of 29 patients. In two instances CathTrack was abandoned and fluoroscopy utilized because of difficulty in threading the initial guidewire into the superior vena cava. CONCLUSION: The CathTrack electromagnetic locator system can be used to reliably position catheters for the establishment of long-term central venous access. Decreased cost and elimination of radiation exposure are distinct advantages of this system over fluoroscopy.

Journal Article↗
PubMed2002

The first 150 endovascular AAA repairs at a single institution: how steep is the learning curve?

PURPOSE: To determine whether increasing experience with endovascular abdominal aortic aneurysm (AAA) repair in a single institution will result in improved outcome. METHODS: A retrospective review was undertaken of 150 consecutive cases of endovascular AAA repairs performed using the AneuRx device between October 1996 and April 2000 in a university-based medical center. The population was divided into early and late groups of 75 patients each. Endpoints included technical success; complications; early (< or =30-day) morbidity, mortality and rupture; endoleak at discharge and at 1 month; early secondary intervention; proximal neck and iliac tortuosity; extender cuff placement; femoral reconstructions beyond primary repair; total fluoroscopy time; and contrast load. RESULTS: Baseline patient and aneurysm characteristics were similar between the 2 groups. Technical success was 98.7%; 2 cases were converted intraprocedurally owing to difficult iliac access (early group) and a severely angulated proximal neck (late group). There was a tendency toward more frequent use of intraoperative proximal extender cuffs in the early group (12% versus 4% in the late group, p=0.13). Femoral reconstructions were more frequent in the early group (36% versus 19%, p<0.025). While total contrast volume was similar (111 +/- 56 versus 105 +/- 45 mL, p=NS), total fluoroscopy time was significantly reduced (p<0.05) between the early and late groups. CONCLUSION: With attention to detail and careful patient selection, successful endovascular AAA repair can be achieved with very few conversions and low perioperative mortality even during the center's early experience. Evidence indicates, however, that a learning curve definitely exists, as shown by fewer access site problems, more accurate device deployments, and decreased fluoroscopy times as proficiency is attained.

Aged↗
PubMed1996

Effective doses for coronary angiography.

A detailed study of dose data has been made for 100 coronary angiography examinations performed on a digital X-ray unit. Dose-area product (DAP) data have been analysed in terms of fluoroscopy and radiography for different projections. Projections patterns were similar for all cardiologists studied and the contribution to DAP from fluoroscopy was 32%. Data for 10 patients, selected because the percentage contributions to DAP from fluoroscopy and radiography were similar to the mean for the group, were used to derive conversion factors from DAP to effective dose. The mean DAP was 14 Gy cm2 and the effective dose 3.1 mSv. Conversion factors, based on the same protocol, were derived for a range of tube potentials and filtrations for use in estimation of effective doses with other units.

Coronary Angiography↗
PubMed2000

Skin sparing in interventional radiology: the effect of copper filtration.

Complex and lengthy interventional radiological techniques have resulted in a number of patients developing skin reactions in recent years. To safeguard against these side effects, we have investigated the degree to which entrance skin dose can be reduced by inserting 0.18 mm and 0.35 mm copper filtration in the incident beam. The potential reduction was measured on a 22 cm water phantom for each of eight models of a fluoroscopy unit. Using the catheter laboratory fluoroscopy unit on which radiofrequency ablations are routinely performed, we assessed the relative effectiveness of adding filtration and increasing the kV:mA ratio. Image quality was subjectively assessed for diagnostic and therapeutic acceptability in two groups of 10 patients undergoing radiofrequency ablations, pacemaker insertions or electrophysiology studies. One of the groups was screened with 0.35 mm copper filtration in place and the other group acted as the control. Maximum patient skin dose proved difficult to measure directly because of the unpredictable dose pattern. This pattern was studied in four patients using a film method in conjunction with thermoluminescent dosemeters. Copper filtration 0.35 mm thick inserted in the beams of the eight fluoroscopy units produced a mean reduction in entrance dose to the phantom of 58% with a mean increase in tube loading of 29%. At 100 kV the increased loading on the X-ray tube was equivalent to increasing the anteroposterior separation of the patient by 2 cm. Measurements on the catheter laboratory unit showed that the tube voltage would need to be raised above the normal diagnostic range to obtain an equivalent entrance dose reduction without the filter. The blackening of films under the patients showed complex patterns, but the estimated skin doses were consistent with those predicted by the phantom experiments. All six cardiologists considered there to be insignificant detriment to image quality in the procedures investigated.

Copper↗
PubMed2003

Ultrasound-guided transbronchial needle aspiration: an experience in 242 patients.

STUDY OBJECTIVES: Conventional transbronchial needle aspiration (TBNA) is a valuable procedure but remains underutilized. Recently, imaging guidance such as CT fluoroscopy has created considerable interest. As CT fluoroscopy is cumbersome and exposes patients and staff to radiation, we have examined the feasibility of endobronchial ultrasound (EBUS) in providing imaging support for TBNA. DESIGN: Prospective consecutive patient enrollment. SETTING: University-related tertiary referral centers for pulmonary diseases. RESULTS: From January 1999 to January 2000, 242 consecutive patients were entered into this prospective study (82 women and 160 men; mean age, 60.0 years). Indications for TBNA were diagnosis of enlarged lymph nodes and cancer staging. The average lymph node size was 1.7 cm (SD, 0.47; range, 0.8 to 4.3 cm). Target lymph nodes were visualized with EBUS, followed by TBNA in standard fashion. All targets could be visualized with EBUS. In 207 patients, the lymph nodes were successfully sampled (86%). This was independent of lymph node size and location. A firm diagnosis or cancer stage could be obtained in 172 patients (72%). There were no complications associated with the use of EBUS. CONCLUSION: EBUS is simply performed and if used for TBNA guidance affords an excellent yield independent of lymph node location. Randomized trials comparing standard TBNA and imaging-guided TBNA by CT fluoroscopy and EBUS are indicated.

Adult↗