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PubMedDate not supplied

A low-cost system for digital image processing of moving images in real time: application to X-ray fluoroscopy.

A low-cost image processing system and two real-time digital image processing algorithms using parallel processing have been developed to provide automatic equalization of moving images at video frequencies. The algorithms differ in the processing time required and the characteristics of the final image. The system takes an entire image from the video sequence, digitizes it, automatically calculates its histogram and the lowest and highest useful grey levels, equalizes the histogram, and finally converts it to the analogue image. Methods were applied to X-ray fluoroscopy (angiography) images, which are usually saturated or of uniform intensity (low contrast), leading to information loss. An application of these methods is in interventional radiography, which requires images in real time.

Algorithms↗
PubMed2005

Visualization of femorotibial contact in total knee arthroplasty using X-ray fluoroscopy.

The purpose of this study was to build a visualization technique of the femorotibial contact in fixed-bearing total knee arthroplasty (TKA) using X-ray fluoroscopy, and to apply this technique to a TKA patient during dynamic motion. In vivo kinametcis of the metallic knee implant was determined using a 2D/3D registration technique, which uses computer assisted design (CAD) model of the implant to estimate the 3D pose of radiopaque metallic femoral and tibial components from a single-plane fluoroscopic image. In fixed-bearing TKA, a 3D pose of radiolucent tibial polyethylene insert can be determined from the estimated pose of the tibial component. To visualize femorotibial contact, the proximity between surfaces of femoral component and tibial insert was calculated, and mapped onto the insert surface model. For the clinical application, dynamic states of contact on the tibial insert were observed including axial rotation and unilateral loading during knee flexion, and post-cam contact of posterior stabilized TKA. The present technique provided us new information and enabled us to better understand the relationship between in vivo knee kinematics and articular shape of the implant.

Arthroplasty, Replacement, Knee↗
PubMed2006

Three-dimensional kinematics and kinetics of total knee arthroplasty during level walking using single plane video-fluoroscopy and force plates: a pilot study.

The goal of the study was to simultaneously obtain accurate kinematic and kinetic data from a total knee arthroplasty (TKA) during level walking, by coupling force plate data with the kinematics of TKA measured by a movable video-fluoroscopic system. Kinematic and kinetic information of a TKA is crucial for the improvement of implant designs and for the increased longevity of the implant components. Instrumented gait analysis, with skin mounted marker tracking and force plates, is a well-established method for the acquisition of kinematic and kinetic data of TKA in vivo and for non-invasive estimation of joint function. However, resultant moments at the knee joint are inaccurate with this method, due to skin movement artifacts. Video-fluoroscopy reduces these inaccuracies by means of the direct tracking of the implant components with X-ray. However this measuring technique carries disadvantages: it provides only kinematic data, and the image intensifier covers a limited field of view. This paper presents a newly developed measuring technique, which enables a more accurate resultant moments calculation for level walking than could be achieved by conventional instrumented gait analysis.

Arthroplasty, Replacement, Knee↗
PubMed2005

Transnasal endoscopy vs. fluoroscopy for the placement of nasoenteric feeding tubes in critically ill patients.

BACKGROUND: Placement of a nasoenteric feeding tube (NET) beyond the pylorus in critically ill patients is desirable. Bedside methods are unreliable, and fluoroscopic methods require transport and/or radiation exposure. Traditional endoscopic methods require sedation and oronasal transfer techniques. Transnasal techniques of NET placement by using recently developed ultrathin endoscopes have been described. The object of this prospective study was to compare the efficacy of NET placement by using ultrathin transnasal endoscopy vs. fluoroscopic placement. METHODS: This is a prospective randomized study of endoscopic vs. fluoroscopic NET placement. The settings of the study were intensive care units at academic medical center. The study included 100 consecutive patients who required NET placement. They received endoscopic NET placement at the bedside with a 5.1-mm, ultrathin endoscope by using a transnasal over-the-wire technique vs. fluoroscopic NET placement by using standard techniques. The procedure success was defined as postpyloric (beyond the duodenal bulb) NET placement, jejunal placement success, and procedure time. RESULTS: Tube placement success was not significantly different between endoscopic and fluoroscopic methods (90% with both methods; p = 1.00). The endoscopic procedure duration (12.8 +/- 6.4 minutes) was significantly shorter than fluoroscopic procedure duration (19.3 +/- 12.0 minutes) (p < 0.001). Procedure duration decreased significantly (from 17.3 +/- 6.2 minutes to 8.0 minutes +/- 4.2 minutes, p = 0.04), and jejunal placement increased significantly (from 60% to 100%, p = 0.04) from the first to the last 10 endoscopic procedures. CONCLUSIONS: NET placement success with an ultrathin transnasal endoscope is equivalent to fluoroscopic placement with faster procedure times. More distal placement and procedure times improve with increasing experience with the endoscopic technique. Endoscopic NET placement can be performed at the bedside without the need for oronasal transfer, additional sedation, or fluoroscopy.

Adolescent↗
PubMed1998

Technical report: The introduction of a new synchronized oesophageal manometry and digital video-fluoroscopy (fluoromanometry) system into the radiology suite.

Following the development of a new fluoromanometry system enabling synchronous oesophageal manometry and barium swallow video-fluoroscopy, both the equipment and examination method have been successfully introduced into the radiology suite. The application of the system which uses a PC with video capture and a portable manometry recorder is described together with details of its implementation and the examination technique used.

Barium↗
PubMed2000

The role of fluoroscopy in avoiding rotational deformity of treated femoral shaft fractures: an anatomical and clinical study.

In the first part of the study we examined the accuracy of femoral anteversion (AV) determined by fluoroscopy, simulating a method used in closed intramedullary femoral nailing. Twenty cadaveric femora were used. The condyles and posterior trochanteric area were resting on a horizontal table. The proximal femur was imaged using a C-arm image intensifier with horizontal X-ray beam at an angle of 30, 45, or 60 degrees to the long axis of the femoral shaft. To evaluate the reliability of the measurements, the real AV angle was determined by radiography. A small difference (mean 2 degrees ) was found between the real AV angle and the angle between the horizontal plane and the central head-neck axis (NH angle) as displayed by the image intensifier. In a separate clinical study, the NH angle was assessed and used as a guide to intraoperative rotational reduction in ten patients with femoral shaft fracture using the aforementioned method. Follow-up examinations of the AV angle showed that rotational deformities of clinical significance were avoided.

Aged↗
PubMed1981

Diagnosis and percutaneous drainage of a perinephric abscess by ultrasound and fluoroscopy.

We describe 3 patients with perinephric abscesses in whom the perinephric fluid collections were identified by ultrasonic examination. In 2 cases thin needle aspiration of these collections using sonographic guidance provided the preoperative diagnosis. Percutaneous tube drainage under ultrasound and fluoroscopy was used successfully in 1 patient whose medical condition precluded surgical drainage. We recommend that percutaneous drainage be considered in severely ill patients with perinephric abscesses.

Abscess↗
PubMed1999

Use of digital ciné-fluoroscopy and catheter-directed techniques to improve and simplify standard vascular procedures.

Digital ciné-fluoroscopy and catheter-directed treatments have become indispensable tools in the armamentarium of surgeons performing vascular procedures. These new technologies not only improve and simplify the performance of standard vascular operations but also allow surgeons to perform a wide range of interventions previously unavailable in the operating room.

Angiography↗
PubMed2001

Use of digital subtraction fluoroscopy to diagnose radiolucent aspirated foreign bodies in infants and children.

OBJECTIVES: Most tracheobronchial foreign bodies in children are radiolucent, and accurate diagnosis of such foreign bodies is not always easy. This can result in delay of diagnosis or misdiagnosis of foreign body aspiration. We report the usefulness and pitfalls of use of digital subtraction fluoroscopy (DSF) to diagnose radiolucent aspirated foreign bodies in infants. METHODS: From 1991 through 1999, DSF was conducted for a total of 19 patients (ranged from 11 months to 4 years and 7 months in age (mean 1.8+/-0.9 years)) who were suspected to have radiolucent aspirated foreign bodies. Since DSF revealed abnormal findings in a trachea or main bronchus in 18 cases, inspection was performed for foreign body bronchofiberscopically. In the one remaining case, no abnormality was recognized on DSF, but since the symptoms at the time of onset strongly suggested aspirated foreign body, bronchofiberscopy was also performed. RESULTS: Foreign body was verified bronchoscopically in 13 of 19 cases, and all 13 (100%) had abnormal findings on DSF, including obstruction of the trachea in two, obstruction of the bronchial lumen in nine, and indistinct visualization of the bronchial lumen in two. Bronchial stenosis was verified bronchoscopically in five of the remaining six cases, including mucus plug in three, granuloma in one and mucosal edema in one case. All five patients (100%) had abnormal findings on DSF, including obstruction of the bronchial lumen in four and indistinct visualization of the bronchial lumen in one. In the one remaining patient with normal findings of DSF, no foreign body or pathological bronchial changes were noted. CONCLUSIONS: DSF was very sensitive in the diagnosis of foreign body aspiration and stenotic changes in the bronchial lumen. However, its diagnostic specificity for aspirated foreign body itself was not high (17%). Therefore, when abnormalities are found on DSF, we recommend to perform flexible bronchofiberscopy initially under general anesthesia via a tracheal tube. When a foreign body is verified, rigid ventilation bronchoscopy is successively performed to retrieve the foreign body.

Bronchi↗
PubMed2001

The feasibility and safety of fluoroscopy-guided percutaneous intramyocardial gene injection in porcine heart.

BACKGROUND: Catheter-based transendocardial gene injection would be useful for the delivery of genes into the heart. We examined the feasibility and safety of percutaneous intramyocardial gene injections with fluoroscopic guidance alone. METHODS: We performed the procedure through an 8F arterial sheath inserted into the left carotid artery. In protocol 1, a mixture of India ink and normal saline was injected through a needle injection catheter in six pigs. We monitored blood pressure and ECG continuously during the procedure. Echocardiography, left ventriculography, and coronary angiography were performed. All pigs were sacrificed 2 days later and hearts were harvested. In protocol 2, a mixture of India ink and plasmid encoding CAT gene was injected in the same manner in eight pigs. Myocardial tissue was obtained 7 days after the procedure to assess gene expression. In protocol 3, four pigs were intentionally needle-perforated in the ventricular wall and were observed for 7 days. RESULTS: In protocol 1, there was no significant hemodynamic changes or serious arrhythmias during the procedure. Echocardiography and angiography revealed no evidence indicating pericardial effusion or wall motion abnormalities. Harvested hearts revealed one intramyocardial hematoma in a total of 36 injection sites. In protocol 2, the gene expression could be identified in 39 sites out of 48 injections after 7 days. In protocol 3, no animal showed signs indicating cardiac tamponade during the observation period. CONCLUSIONS: Our data suggest that fluoroscopy-guided percutaneous intramyocardial gene injection is a feasible and safe procedure, with no indication of associated significant hemodynamic changes, arrhythmias, or mortality.

Administration, Cutaneous↗
PubMed1998

Subacute radiation dermatitis from fluoroscopy during coronary artery stenting: evidence for cytotoxic lymphocyte mediated apoptosis.

A patient with fluoroscopy-induced subacute radiation dermatitis is described. Her biopsy specimen showed vacuolar change and necrotic keratinocytes with lymphocytes in direct apposition, or "satellitosis". Lymphocytes in the dermis and infiltrating the epidermis were predominantly CD8+ and a number of the lymphocytes stained for TIA-1, a cytotoxic granule protein in T-cells and natural killer cells, that appears to be involved in the induction of apoptosis. Our findings suggest cytotoxic lymphocyte mediated apoptosis is involved in the pathogenesis of subacute radiation dermatitis.

Acute Disease↗
PubMed2005

[Complications of fluoroscopy-, ultrasound-, and CT-guided percutaneous interventional procedures].

The purpose of this article is to describe potential complications following the most common image-guided (fluoroscopy, ultrasound or CT) percutaneous interventional procedures, both diagnostic and therapeutic, thoraco-abdominal and musculoskeletal, as well as to review risk factors and the best practice recommendations. Prior to any interventional procedure, it is necessary to ascertain the absence of any abnormality in coagulation, to secure enough time to explain the procedure to the patient, and to adhere to strict sterile technique. Indeed, infections and hemorrhagic complications are the principal causes of mortality and morbidity for all procedures. Following lung biopsy, CT scan detects an immediate pneumothorax in 30% of patients. Major complications following percutaneous liver biopsy occur within 3 to 6 hours. Following a percutaneous drainage, complications occur in less than 10% of cases. Following a radiofrequency thermal ablation of malignant tumors, the mortality rate is low (0,5 to 1,4%), infection and hemorrhage are the most frequent complications. While rare, septic arthritis is the main complication that can follow musculoskeletal procedures and is a cause of medical malpractice lawsuits brought by patients.

Fluoroscopy↗
PubMedDate not supplied

Computed tomography fluoroscopy: techniques and applications.

Computed tomography fluoroscopy (CTF) was first introduced into clinical practice in Japan in 1993 and in the United States in 1995, yet it has been used predominantly at large academic hospitals. Early literature on CTF is composed primarily of abstracts that detail anecdotal experiences and that have been presented at major meetings. Scientific papers evaluating CTF in clinical practice have been introduced in scientific journals only recently. This article reviews the literature for CTF with specific emphasis on clinical techniques, applications, and results. It is the goal of the author to provide the reader with a basic working knowledge of how to perform CTF-guided procedures and how to integrate CTF into clinical practice.

Dose-Response Relationship, Radiation↗
PubMed2000

Real time CT-fluoroscopy: diagnostic and therapeutic applications.

The synergetic progression of CT technology and computer hardware has made ultrafast acquisition and image reconstruction possible. This has lead to the availability of CT interactive diagnosis and therapeutic procedures. Making use of our own material (337 intervention procedures during the last 17 months), we have compared our techniques and results to the recent literature data. One of the advantages of the biopsy technique is an improved sensitivity for neoplastic lesions, most certainly in cases of intrapulmonary lesions, surrounded by aerated tissue (now 94% compared to 87% in our previous study). A second advantage is the safety of the technique (only one major complication in our series). Fluid collection drainages, and more complex interventions like local injection of drugs, radio-frequency ablation, wire hook placement and ethanol injection were performed without complication. Yet another interesting feature is the shortening of the procedure time (reduced in average to an 'in-room' time of less than 30 min), which has definite economical implications. Furthermore it increases the patient's comfort and safety, and extends the scope of outpatient procedures (80% outpatient procedures in our material). On the other side the radiation exposure can be raised as an issue, especially when we consider the operator's hands. However, the described technique and the use of dedicated tools can alleviate the problem. As a conclusion, real time CT fluoroscopy has given a new input and broadens the scope of clinical indications of CT-guided diagnostic and therapeutic procedures.

Adolescent↗
PubMedDate not supplied

Evaluation of the patellofemoral joint with kinematic MR fluoroscopy.

OBJECTIVE: The aim of this study was to evaluate the diagnostic effectiveness of kinematic magnetic resonance fluoroscopy (KMRF) on patients with patellofemoral incongruency. MATERIALA AND METHODS: 17 patients (20 knees) and 10 healthy volunteers (20 knees), all men (mean age 29.4 years, S.D. 9, range 16-50), were included to our study. Only male subjects were studied because of potential biomechanical differences between sexes. KMRF was used to perform kinematic MR imaging of patellar alignment and tracking in 10 healthy subjects and 17 patients with a provisional clinical diagnosis of abnormal patellofemoral joints. The patellofemoral joints were examined with the knee in different angles of active flexion. At each knee position, real time kinematic and axial MRF image was used to focus on the sagittal plane, followed by an axial image focused through the middle of the patella. Three angles were measured: patellar tilt angle (PTA), sulcus angle (SA) and congruence angle (CA). RESULTS: Five patterns of malalignment were identified and studied. Two patellofemoral joints were normal, 10 had lateralization of the patella, 2 had patellar tilt, 2 had lateralization and patellar tilt (i.e. excessive lateral pressure syndrome) and 4 had medialization of the patella. CONCLUSION: KMRF is an effective method in evaluating patellofemoral incongruency. Short time duration of investigation, ability to get nearly real time images, suitable temporal contrast resolution and investigation from very different angles of knee are important advantages of the method.

Adolescent↗
PubMed2001

[Influence of tandem optics and television tube of modern digital fluoroscopy equipment on image quality].

The influence of the tandem optics and the TV-tube to the image quality of 1k- and 2k-radiographs of a modern fluoroscopy equipment should be assessed on the basis of objective parameters and clinical requirements. Radiographs of different phantoms with 1k- and 2k-image matrix, different illumination point corrections (IPC) and signal gray levels were taken, examined and evaluated, in order to determine the objective image parameters and the clinical relevancy of these parameters. On the one hand, the digital images data could be used directly for evaluation; on the other hand, the radiographs could be visually evaluated by experienced radiologists within the framework of a blind study. The IPC is controlled by the aperture of the iris diaphragm and the insertion of a neutral gray filter in the tandem optics. The larger the aperture of the iris diaphragm (at constant image receiver dose) the higher were gradation, signal to noise ratio (SNR) and image homogeneity. Furthermore, the larger the aperture, the lower was the square wave response function (SWRF). The insertion of a gray filter in the tandem optics decreases gradation, SNR and homogeneity, and improves the SWRF.

Fluoroscopy↗