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Journal ArticleDOI

Evaluation of coronary angiographic projections to balance the clinical yield with the radiation risk

18 Apr 2012-British Journal of Radiology (British Institute of Radiology)-Vol. 85, Iss: 1017
TL;DR: In this paper, an algorithm was developed to combine published data detailing the quality of information derived for the major coronary artery segments through the use of a common set of views in angiography with data relating to the dose-area product and scatter radiation associated with these views.
Abstract: Objective: Radiation safety principles dictate that imaging procedures should minimise the radiation risks involved, without compromising diagnostic performance. This study aims to define a core set of views that maximises clinical information yield for minimum radiation risk. Angiographers would supplement these views as clinically indicated. Methods: An algorithm was developed to combine published data detailing the quality of information derived for the major coronary artery segments through the use of a common set of views in angiography with data relating to the dose–area product and scatter radiation associated with these views. Results: The optimum view set for the left coronary system comprised four views: left anterior oblique (LAO) with cranial (Cr) tilt, shallow right anterior oblique (AP-RAO) with caudal (Ca) tilt, RAO with Ca tilt and AP-RAO with Cr tilt. For the right coronary system three views were identified: LAO with Cr tilt, RAO and AP-RAO with Cr tilt. An alternative left coronary view set including a left lateral achieved minimally superior efficiency (,5%), but with an ,8% higher radiation dose to the patient and 40% higher cardiologist dose. Conclusion: This algorithm identifies a core set of angiographic views that optimises the information yield and minimises radiation risk. This basic data set would be supplemented by additional clinically determined views selected by the angiographer for each case. The decision to use additional views for diagnostic angiography and interventions would be assisted by referencing a table of relative radiation doses for the views being considered.

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Citations
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Journal ArticleDOI
TL;DR: The purpose of this study was to quantify the reduction in patient radiation dose during coronary angiography by a new X‐ray technology, and to assess its impact on diagnostic image quality.
Abstract: 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 Gycm2 to 12 Gycm2, 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. © 2015 Wiley Periodicals, Inc.

39 citations

Journal ArticleDOI
TL;DR: An acousto-optical optical fiber sensor for tracking catheter position during interventional magnetic resonance imaging (MRI) to overcome RF induced heating of active markers and it has been successfully used to detect the position of a tacking coil in phantom in an imaging experiment.
Abstract: Objective: The objective of this paper is to introduce an acousto-optic optical fiber sensor for tracking catheter position during interventional magnetic resonance imaging (MRI) to overcome RF induced heating of active markers. Methods: The sensor uses a miniature coil coupled to a piezoelectric transducer, which is in turn mechanically connected to an optical fiber. The piezoelectric transducer converts the RF signal to acoustic waves in the optical fiber over a region including a fiber Bragg grating (FBG). The elastic waves in the fiber modulates the FBG geometry and hence the reflected light in the optical fiber. Since the coil is much smaller than the RF wavelength and the signal is transmitted on the dielectric optical fiber, the sensor effectively reduces RF induced heating risk. Proof of concept prototypes of the sensor are implemented using commercially available piezoelectric transducers and optical fibers with FBGs. The prototypes are characterized in a 1.5 T MRI system in comparison with an active tracking marker. Results: Acousto-optical sensor shows linear response with flip angle and it can be used to detect signals from multiple coils for potential orientation detection. It has been successfully used to detect the position of a tacking coil in phantom in an imaging experiment. Conclusion: Acousto-optical sensing is demonstrated for tracking catheters during interventional MRI. Real-time operation of the sensor requires sensitivity improvements like using a narrow band FBG. Significance: Acousto-optics provides a compact solution to sense RF signals in MRI with dielectric transmission lines.

11 citations

Journal ArticleDOI
TL;DR: Though a similar amount of patient radiation exposure in each projection was observed among TFA and TRA groups; LAO cranial and LAO caudal projections were associated with a significantly higher operator radiation Exposure in the TRA group.
Abstract: OBJECTIVE We aimed to compare the operator and patient radiation exposure in standard projections during elective diagnostic coronary angiography procedures via transradial (TRA) versus transfemoral (TFA) approaches. METHODS In this analytical cross-sectional study, a total of 202 consecutive patients who were candidates for diagnostic coronary angiography were randomized to undergo the procedure via TFA or TRA approaches (101 in each group). Patients with abnormal Allen test and history of coronary artery bypass surgery, valvular heart disease, and unsuccessful coronary angiography were excluded from the study. A single operator performed all of the procedures using a single angiography system. Patient and operator radiation exposure were measured using diamentor and an electronic personal dosimeter, respectively. Each procedure comprised a standardized sequence of projections including four standard views for the left coronary system and two standard views for the right coronary system. RESULTS Left anterior oblique (LAO) caudal (50°/30°) and right anterior oblique RAO (30°) projections were associated with the highest and lowest patient radiation exposure, respectively. The operator received a significantly higher radiation exposure in the TRA approach for LAO cranial (for both left and right coronary systems) and LAO caudal (for left coronary system) projections during coronary angiography compared with the TFA approach. CONCLUSION Though a similar amount of patient radiation exposure in each projection was observed among TFA and TRA groups; LAO cranial and LAO caudal projections were associated with a significantly higher operator radiation exposure in the TRA group. These findings need to be considered when choosing the optimal arterial approach for patients scheduled for coronary angiography.

7 citations

Journal ArticleDOI
TL;DR: It is suggested that a process relying on elements of comparative effectiveness and the use of standardized BRC may ensure consistent examination of differences among alternatives by way of making explicit implicit trade-offs that otherwise enter the decision-making space and detract from consistency and transparency.

6 citations

Journal ArticleDOI
TL;DR: Specific angiographic projections expose patients to significantly higher radiation and they should be avoided and replaced by less irradiating projections whenever possible.
Abstract: Introduction: We aimed to determine angiography projections with lower Dose Area Product (DAP) rate by measuring the mean DAP and fluoroscopy times in coronary angiography (CAG) and percutaneous coronary intervention (PCI) and calculating DAP rate in different projections. Methods: DAP and fluoroscopy times were measured in all employed projections in real-time in 75 patients who underwent CAG or PCI by a single cardiologist in Madani Cardiovascular University Hospital (45 in CAG group and 30 in PCI group). DAP rate was calculated in both groups and in all projections. The projections with highest and lowest DAP rate were determined. Results: Mean DAP was 436.73±315.85 dGy×cm2 in CAG group and 643.26±359.58 dGy×cm2 in PCI group. The projection 40° LAO/0° had the highest DAP rate in CAG group (28.98 dGy×cm2/ sec) and it was highest in 20° RAO/30° CR in PCI group (29.83 dGy×cm2/sec). The latter projection was also the most employed projection in PCI group. Conclusion: The amount of radiation dose in this study is in consistent with the previous reports. Specific angiographic projections expose patients to significantly higher radiation and they should be avoided and replaced by less irradiating projections whenever possible.

6 citations

References
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Journal ArticleDOI
TL;DR: Radiation exposure metrics for common cardiac angiography imaging procedures have been documented and linked to procedure complexity, which has implications for performance monitoring when comparing radiation usage between users, facilities, times and technologies.
Abstract: Background Although it is important for a patient's radiation related risks to be considered when recommending a cardiac imaging procedure, few clinicians appreciate the level of exposure involved This paper provides a comprehensive set of radiation exposure metrics for common angiography procedures highlighting links to factors that influence radiation dose Methods Radiation use metrics and various clinical findings for diagnostic procedures and number of lesions treated, vessels treated and stents deployed for interventional cases were analysed Results Data relating to 1088 coronary angiography (CA), 256 angioplasty and 167 CA/angioplasty procedures were examined The median effective dose (E) (mSv) for these procedures (including inter-quartile range) were, respectively, 33 (21–51), 75 (45–141) and 116 (69–161) For CA, E varied with the number of vessels (p Conclusion Radiation exposure metrics for common cardiac angiography imaging procedures have been documented and linked to procedure complexity This has implications for performance monitoring when comparing radiation usage between users, facilities, times and technologies

20 citations

Journal ArticleDOI
TL;DR: The study affirmed that using a reduced cine frame rate, low dose pulsed fluoroscopy, added copper filtration and a conscious effort to reduce screening time can significantly reduce patient dose.
Abstract: Background: Coronary angiography is a commonly performed diagnostic procedure with life saving benefits for the patient. However, because of its potential to deliver a high radiation dose, caution is warranted. Aim: The purpose of this study was to determine the effective dose to an average patient from coronary angiography, to estimate the associated radiation risk in terms of fatal malignancy, and to examine ways effective dose may be reduced. Method: The dose-area product data from 210 examinations was used to determine the effective dose to the average patient by means of a commercially available software programme. Subsequently, the effective dose was used to estimate radiation risk based on the population averaged probability coefficients given in ICRP 60 and contrasted against age-related risk coefficients from the NRPB. The components of effective dose and radiation risk were examined to identify the organs most at risk. Results: The average effective dose was found to be 3.4±1.3 mSv. The risk of fatal malignancy was estimated as 170 per million cases, or around one in 6000. The average lung dose was 14.7 mSv, with the risk of fatal lung cancer estimated as 125 per million cases or one in 8000. Conclusions: The average effective dose in this study was less than half that of most other studies. The lung was identified as the critical organ and the estimated risk of fatal cancer amounted to an increase of 0.017% above the normal incidence for the general population. The study affirmed that using a reduced cine frame rate, low dose pulsed fluoroscopy, added copper filtration and a conscious effort to reduce screening time can significantly reduce patient dose.

17 citations

Journal ArticleDOI
TL;DR: This work represents one of the largest and most detailed published studies of patient radiation dose during cardiac procedures, and should assist in meeting the IR(ME)R regulations requirement for establishment of diagnostic reference levels, and in enabling dose optimization of individual exposures.
Abstract: Patient radiation doses delivered during invasive fluoroscopic cardiology procedures at the University Hospital of North Staffordshire during a 3 year period from November 1999 to August 2002, and comprising 6189 patient records, have been analysed. Cases have been stratified using classification codes from the Office of Population Census and Surveys (OPCS-4 codes), allowing representative doses to be assessed for 34 distinct types of cardiac radiological procedure. In addition, local guidance levels have been derived for the eight most common procedures. This work represents one of the largest and most detailed published studies of patient radiation dose during cardiac procedures, and should assist in meeting the IR(ME)R regulations requirement for establishment of diagnostic reference levels, and in enabling dose optimization of individual exposures.

13 citations

Journal Article
TL;DR: The physiopathogenesis of CIN is reviewed, as well as the clinical manifestations and preventive measures currently available, in patients undergoing cardiac catheterization and high-risk subgroups.
Abstract: Contrast-medium induced nephropathy (CIN) in patients undergoing cardiac catheterization has an extremely variable incidence, which is very elevated in high-risk subgroups. Despite its benign course in most cases, it is associated with a longer hospital stay, and elevated in-hospital and late mortality rates. This paper reviews the physiopathogenesis of CIN, as well as the clinical manifestations and preventive measures currently available.

10 citations