Agreement Among Radiographs, Fluoroscopy and Bronchoscopy in Documentation of Airway Collapse in Dogs.

BackgroundAirway collapse is a common finding in dogs with chronic cough, yet the diagnosis can be difficult to confirm without specialty equipment.HypothesisBronchoscopic documentation of tracheobronchial collapse will show better agreement with fluoroscopic imaging than with standard radiography.AnimalsForty-two dogs prospectively evaluated for chronic cough.MethodsIn this prospective study, three-view thoracic radiographs were obtained followed by fluoroscopy during tidal respiration and fluoroscopy during induction of cough. Digital images were assessed for the presence or absence of collapse at the trachea and each lobar bronchus. Bronchoscopy was performed under general anesthesia for identification of tracheobronchial collapse at each lung segment. Agreement of imaging tests with bronchoscopy was evaluated along with sensitivity and specificity of imaging modalities as compared to bronchoscopy.ResultsAirway collapse was identified in 41/42 dogs via 1 or more testing modalities. Percent agreement between pairs of tests varied between 49 and 87% with poor-moderate agreement at most bronchial sites. Sensitivity for the detection of bronchoscopically identified collapse was highest for radiography at the trachea, left lobar bronchi, and the right middle bronchus, although specificity was relatively low. Detection of airway collapse was increased when fluoroscopy was performed after induction of cough compared to during tidal respiration.ConclusionsRadiography and fluoroscopy are complementary imaging techniques useful in the documentation of bronchial collapse in dogs. Confirming the presence or absence of tracheal or bronchial collapse can require multiple imaging modalities as well as bronchoscopy

Local DRLs and automated risk estimation in paediatric interventional cardiology

Introduction : Cardiac catheterization procedures result in high radiation doses and often multiple procedures are necessary for congenital heart disease patients. However, diagnostic reference levels (DRL) remain scarce. Our first goal was finding the optimal DRL parameter and determining appropriate DRLs. The second goal was to calculate organ doses (OD), effective doses (ED) and lifetime attributable risks (LAR) per procedure and to provide conversion factors based on dose area product (DAP). Materials and methods : DRLs are calculated for each procedure type, as the 75th percentile of the cumulative value per procedure from the corresponding parameter. All irradiation events in the DICOM Structured Reports were automatically processed and simulated using PCXMC, resulting in OD, ED and LAR. Using a Kruskal Wallis H test and subsequent pairwise comparisons, differences in median values of the DRL parameter between procedure types were assessed. Results : Linear regression showed a strong correlation and narrow confidence interval between DAP and product of body weight and fluoroscopy time (BWxFT), even when all procedures (diagnostic and interventional) are combined. Only 15% of the pairwise comparisons were statistically significant for DAP normalized to BWxFT (DAP(BWxFT)). The latter pairs contained less frequent procedure types with significant outliers. For DAP normalized to BW (DAP(BW)), 38% of the pairwise comparisons showed statistically significant differences. Conversion factors from DAP(BW) to OD and ED were reported for various weight groups, due to the higher correlation between DAP(BW) and both OD and ED than between DAP and both OD and ED. Conclusions : The P75 of DAP(BWxFT) for all procedures combined serves as an appropriate DRL value. This facilitates local DRL determination in smaller paediatric centres, which often have insufficient data to produce appropriate DRLs for different procedure types. Conversion factors are more reliable starting from DAP(BW) instead of DAP and should be used according to the appropriate BW group

Novel X-ray imaging technology enables significant patient dose reduction in interventional cardiology while maintaining diagnostic image quality

Objectives: The purpose of this study was to quantify the reduction in patient radiation dose during coronary angiography (CA) by a new X-ray technology, and to assess its impact on diagnostic image quality. Background: Recently, a novel X-ray imaging technology has become available for interventional cardiology, using advanced image processing and an optimized acquisition chain for radiation dose reduction. Methods: 70 adult patients were randomly assigned to a reference X-ray system or the novel X-ray system. Patient demographics were registered and exposure parameters were recorded for each radiation event. Clinical image quality was assessed for both patient groups. Results: With the same angiographic technique and a comparable patient population, the new imaging technology was associated with a 75% reduction in total kerma-area product (KAP) value (decrease from 47 Gycm(2) to 12 Gycm(2), P<0.001). Clinical image quality showed an equivalent detail and contrast for both imaging systems. On the other hand, the subjective appreciation of noise was more apparent in images of the new image processing system, acquired at lower doses, compared to the reference system. However, the higher noise content did not affect the overall image quality score, which was adequate for diagnosis in both systems. Conclusions: For the first time, we present a new X-ray imaging technology, combining advanced noise reduction algorithms and an optimized acquisition chain, which reduces patient radiation dose in CA drastically (75%), while maintaining diagnostic image quality. Use of this technology may further improve the radiation safety of cardiac angiography and interventions

Comparative ergonomic workflow and user experience analysis of MRI versus fluoroscopy-guided vascular interventions:an iliac angioplasty exemplar case study

Purpose A methodological framework is introduced to assess and compare a conventional fluoroscopy protocol for peripheral angioplasty with a new magnetic resonant imaging (MRI)-guided protocol. Different scenarios were considered during interventions on a perfused arterial phantom with regard to time-based and cognitive task analysis, user experience and ergonomics. Methods Three clinicians with different expertise performed a total of 43 simulated common iliac angioplasties (9 fluoroscopic, 34 MRI-guided) in two blocks of sessions. Six different configurations for MRI guidance were tested in the first block. Four of them were evaluated in the second block and compared to the fluoroscopy protocol. Relevant stages’ durations were collected, and interventions were audio-visually recorded from different perspectives. A cued retrospective protocol analysis (CRPA) was undertaken, including personal interviews. In addition, ergonomic constraints in the MRI suite were evaluated. Results Significant differences were found when comparing the performance between MRI configurations versus fluoroscopy. Two configurations [with times of 8.56 (0.64) and 9.48 (1.13) min] led to reduce procedure time for MRI guidance, comparable to fluoroscopy [8.49 (0.75) min]. The CRPA pointed out the main influential factors for clinical procedure performance. The ergonomic analysis quantified musculoskeletal risks for interventional radiologists when utilising MRI. Several alternatives were suggested to prevent potential low-back injuries. Conclusions This work presents a step towards the implementation of efficient operational protocols for MRI-guided procedures based on an integral and multidisciplinary framework, applicable to the assessment of current vascular protocols. The use of first-user perspective raises the possibility of establishing new forms of clinical training and education

A new mini-navigation tool allows accurate component placement during anterior total hip arthroplasty.

Introduction: Computer-assisted navigation systems have been explored in total hip arthroplasty (THA) to improve component positioning. While these systems traditionally rely on anterior pelvic plane registration, variances in soft tissue thickness overlying anatomical landmarks can lead to registration error, and the supine coronal plane has instead been proposed. The purpose of this study was to evaluate the accuracy of a novel navigation tool, using registration of the anterior pelvic plane or supine coronal plane during simulated anterior THA. Methods: Measurements regarding the acetabular component position, and changes in leg length and offset were recorded. Benchtop phantoms and target measurement values commonly seen in surgery were used for analysis. Measurements for anteversion and inclination, and changes in leg length and offset were recorded by the navigation tool and compared with the known target value of the simulation. Pearson\u27s Results: The device accurately measured cup position and leg length measurements to within 1° and 1 mm of the known target values, respectively. Across all simulations, there was a strong, positive relationship between values obtained by the device and the known target values ( Conclusion: The preliminary findings of this study suggest that the novel navigation tool tested is a potentially viable tool to improve the accuracy of component placement during THA using the anterior approach

The role of the GI radiographer: A UK perspective

Context: Since the 1990s radiographers in the United Kingdom have expanded their role in gastrointestinal (GI) radiology, first by performing double-contrast barium enema (DCBE) examinations independently and later by interpreting and reporting the results of these exams. Objective: This article will trace the evolution of GI radiographers in the United Kingdom, evaluate their success and explore how the U.K. experience could apply to American radiologist assistants. Methods: The authors surveyed the professional literature to determine the historical context in which GI radiographers emerged and assess how their performance on DCBE exams compares with radiologists’ performance. Results: DCBE exams performed by GI radiographers have been shown to be efficient, cost effective and safe. In addition, GI radiographers have helped reduce waiting and turnaround times for DCBE exams. Summary: The success of GI radiographers in the United Kingdom offers assurance that radiologist assistants can benefit American patients, radiologists and radiologic technologists

Heparin and air filters reduce embolic events caused by intra-arterial cerebral angiography - A prospective, randomized trial

Background-Intra-arterial cerebral angiography is associated with a low risk for neurological complications, but clinically silent ischemic events after angiography have been seen in a substantial number of patients.Methods and Results-In a prospective study, diffusion-weighted magnetic resonance imaging (DW-MRI) before and after intra-arterial cerebral angiography and transcranial Doppler sonography during angiography were used to evaluate the frequency of cerebral embolism. One hundred fifty diagnostic cerebral angiographies were randomized into 50 procedures, each using conventional angiographic technique, or systemic heparin treatment throughout the procedure, or air filters between the catheter and both the contrast medium syringe and the catheter flushing. There was no neurological complication during or after angiography. Overall, DW-MRI revealed 26 new ischemic lesions in 17 patients (11%). In the control group, 11 patients showed a total of 18 lesions. In the heparin group, 3 patients showed a total of 4 lesions. In the air filter group, 3 patients exhibited a total of 4 lesions. The reduced incidence of ischemic events in the heparin and air filter groups compared with the control group was significantly different (P=0.002). Transcranial Doppler sonography demonstrated a large number of microembolic signals that was significantly lower in the air filter group compared with the heparin and control groups (P=0.01), which did not differ from each other.Conclusions-Air filters and heparin both reduce the incidence of silent ischemic events detected by DW-MRI after intra-arterial cerebral angiography and can potentially lower clinically overt ischemic complications. This may apply to any intra-arterial angiographic procedure

Stereotactic guidance for navigated percutaneous sacroiliac joint fusion.

Arthrodesis of the sacroiliac joint (SIJ) for surgical treatment of SIJ dysfunction has regained interest among spine specialists. Current techniques described in the literature most often utilize intraoperative fluoroscopy to aid in implant placement; however, image guidance for SIJ fusion may allow for minimally invasive percutaneous instrumentation with more precise implant placement. In the following cases, we performed percutaneous stereotactic navigated sacroiliac instrumentation using O-arm® multidimensional surgical imaging with StealthStation® navigation (Medtronic, Inc. Minneapolis, MN). Patients were positioned prone and an image-guidance reference frame was placed contralateral to the surgical site. O-arm® integrated with StealthStation® allowed immediate auto-registration. The skin incision was planned with an image-guidance probe. An image-guided awl, drill and tap were utilized to choose a starting point and trajectory. Threaded titanium cage(s) packed with autograft and/or allograft were then placed. O-arm® image-guidance allowed for implant placement in the SIJ with a small skin incision. However, we could not track the cage depth position with our current system, and in one patient, the SIJ cage had to be revised secondary to the anterior breach of sacrum

2D-3D registration of CT vertebra volume to fluoroscopy projection: A calibration model assessment (doi:10.1155/2010/806094)

This study extends a previous research concerning intervertebral motion registration by means of 2D dynamic fluoroscopy to obtain a more comprehensive 3D description of vertebral kinematics. The problem of estimating the 3D rigid pose of a CT volume of a vertebra from its 2D X-ray fluoroscopy projection is addressed. 2D-3D registration is obtained maximising a measure of similarity between Digitally Reconstructed Radiographs (obtained from the CT volume) and real fluoroscopic projection. X-ray energy correction was performed. To assess the method a calibration model was realised a sheep dry vertebra was rigidly fixed to a frame of reference including metallic markers. Accurate measurement of 3D orientation was obtained via single-camera calibration of the markers and held as true 3D vertebra position; then, vertebra 3D pose was estimated and results compared. Error analysis revealed accuracy of the order of 0.1 degree for the rotation angles of about 1?mm for displacements parallel to the fluoroscopic plane, and of order of 10?mm for the orthogonal displacement.<br/