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Massera RT, Dehairs M, Verhoeven H, Bosmans H, Marshall N. A comprehensive assessment of a prototype high ratio antiscatter grid in interventional cardiology using experimental measurements and Monte Carlo simulations. Phys Med Biol 2024; 69:135015. [PMID: 38862002 DOI: 10.1088/1361-6560/ad56f3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 06/11/2024] [Indexed: 06/13/2024]
Abstract
Objective. To assess the performance of a new antiscatter grid design in interventional cardiology for image quality improvement and dose reduction using experimental measurements and Monte Carlo (MC) simulation.Approach.Experimental measurements were performed on an angiography system, using a multi-layered tissue simulating composite phantom made from of poly(methyl methacrylate), aluminium and expanded polystyrene (2/0.2/0.7 cm). The total phantom thickness ranged from 20.3 cm to 40.6 cm. Four conditions were compared; (A) 105 cm source-image receptor distance (SID) without grid, (Bi) 105 cm SID with grid ratio (r) and strip density (N) (r15N80), (Bii) 120 cm SID without grid, and (Biii) 120 cm SID with high ratio grid (r29N80). The system efficiency (η), defined by the signal-to-noise ratio, was compared from theBconditions against caseA. These conditions were also simulated with MC techniques, allowing additional phantom compositions to be explored. Weighted image quality improvement factor (ηw(u)) was studied experimentally at a specific spatial frequency due to the SID change. Images were simulated with an anthropomorphic chest phantom for the different conditions, and the system efficiency was compared for the different anatomical regions.Main results.Good agreement was found between theηandηw(u) methods using both measured and simulated data, with average relative differences between 2%-11%. CaseBiiiprovided higherηvalues compared toA, andBifor thicknesses larger than 20.3 cm. In addition, caseBiiialso provided higherηvalues for high attenuating areas in the anthropomorphic phantom, such as behind the spine.Significance.The new antiscatter grid design provided higher system efficiency compared to the standard grid for the parameters explored in this work.
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Affiliation(s)
- Rodrigo T Massera
- Medical Imaging Research Centre, Medical Physics and Quality Assessment, KU Leuven, 3000 Leuven, Belgium
| | - Michiel Dehairs
- Medical Imaging Research Centre, Medical Physics and Quality Assessment, KU Leuven, 3000 Leuven, Belgium
- Department of Medical Physics, Institute Jules Bordet Instituut, Rue Meylemeersch 90, Bruxelles 1070, Belgium
| | - Hannelore Verhoeven
- Competentiecentrum medische stralingsfysica, UZ Gasthuisberg, Herestraat 49, 3000 Leuven, Belgium
| | - Hilde Bosmans
- Medical Imaging Research Centre, Medical Physics and Quality Assessment, KU Leuven, 3000 Leuven, Belgium
- Competentiecentrum medische stralingsfysica, UZ Gasthuisberg, Herestraat 49, 3000 Leuven, Belgium
| | - Nicholas Marshall
- Medical Imaging Research Centre, Medical Physics and Quality Assessment, KU Leuven, 3000 Leuven, Belgium
- Competentiecentrum medische stralingsfysica, UZ Gasthuisberg, Herestraat 49, 3000 Leuven, Belgium
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Werncke T, Becker LS, Maschke SK, Hinrichs JB, Meine TCH, Dewald CLA, Brüsch I, Rumpel R, Wacker FK, Meyer BC. Image Quality and Radiation Exposure in Abdominal Angiography: A Head-to-Head Comparison of Conventional Detector-Dose-Driven Versus Contrast-to-Noise Ratio-Driven Exposure Control at Various Source-to-Image Receptor Distances and Collimations in a Pilot Phantom and Animal Study. Invest Radiol 2024:00004424-990000000-00205. [PMID: 38529924 DOI: 10.1097/rli.0000000000001079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/27/2024]
Abstract
OBJECTIVES This phantom and animal pilot study aimed to compare image quality and radiation exposure between detector-dose-driven exposure control (DEC) and contrast-to-noise ratio (CNR)-driven exposure control (CEC) as functions of source-to-image receptor distance (SID) and collimation. MATERIALS AND METHODS First, an iron foil simulated a guide wire in a stack of polymethyl methacrylate and aluminum plates representing patient thicknesses of 15, 25, and 35 cm. Fluoroscopic images were acquired using 5 SIDs ranging from 100 to 130 cm and 2 collimations (full field of view, collimated field of view: 6 × 6 cm). The iron foil CNRs were calculated, and radiation doses in terms of air kerma rate were obtained and assessed using a multivariate regression. Second, 5 angiographic scenarios were created in 2 anesthetized pigs. Fluoroscopic images were acquired at 2 SIDs (110 and 130 cm) and both collimations. Two blinded experienced readers compared image quality to the reference image using full field of view at an SID of 110 cm. Air kerma rate was obtained and compared using t tests. RESULTS Using DEC, both CNR and air kerma rate increased significantly at longer SID and collimation below the air kerma rate limit. When using CEC, CNR was significantly less dependent of SID, collimation, and patient thickness. Air kerma rate decreased at longer SID and tighter collimation. After reaching the air kerma rate limit, CEC behaved similarly to DEC. In the animal study using DEC, image quality and air kerma rate increased with longer SID and collimation (P < 0.005). Using CEC, image quality was not significantly different than using longer SID or tighter collimation. Air kerma rate was not significantly different at longer SID but lower using collimation (P = 0.012). CONCLUSIONS CEC maintains the image quality with varying SID and collimation stricter than DEC, does not increase the air kerma rate at longer SID and reduces it with tighter collimation. After reaching the air kerma rate limit, CEC and DEC perform similarly.
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Affiliation(s)
- Thomas Werncke
- From the Department of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany (T.W., L.S., S.K.M., T.C.M., C.L.A., F.K.W., B.C.M.); Department of Diagnostic and Interventional Radiology and Neuroradiology, St. Bernward Hospital, Hildesheim, Germany (J.B.H.); and Institute for Laboratory Animal Science and Central Animal Facility, Hannover Medical School, Hannover, Germany (I.B., R.R.)
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Anthony G, Liang Y, Zhao X. Performance evaluation of two interventional fluoroscope suites for cardiovascular imaging. J Appl Clin Med Phys 2022; 23:e13741. [PMID: 35950644 DOI: 10.1002/acm2.13741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 06/28/2022] [Accepted: 07/02/2022] [Indexed: 11/09/2022] Open
Abstract
Interventional cardiology involves catheter-based treatment of heart disease, generally through fluoroscopically guided interventional procedures. Patients can be subject to considerable radiation dose due to prolonged fluoroscopy time and radiographic exposure, and therefore efforts to minimize patient dose should always be undertaken. Developing standardized, effective quality control programs for these systems is a difficult task owing to cross-vendor differences and automated control of imaging protocols. Furthermore, analyses of radiation dose should be performed in the context of its associated effects on image quality. The aim of the study is to investigate radiation dose and image quality in two fluoroscopic systems used for interventional cardiology procedures. Image quality was assessed in terms of spatial resolution and modulation transfer function, signal-to-noise and contrast-to-noise ratios, and spatial-temporal resolution of fluoroscopy and cineradiography images with phantoms simulating various patient thicknesses under routine cardiology protocols. The entrance air kerma (or air kerma rate) was measured and used to estimate entrance surface dose (or dose rate) in the phantoms.
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Affiliation(s)
- Gregory Anthony
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, Indiana, USA.,Krannert Cardiovascular Research Center, Indiana University School of Medicine/IU Health Cardiovascular Institute, Indianapolis, Indiana, USA
| | - Yun Liang
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Xuandong Zhao
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, Indiana, USA
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Werncke T, Meine TC, Hinrichs JB, Maschke SK, Becker LS, Brüsch I, Rumpel R, Wacker FK, Meyer BC. Tantalum-specific contrast-to-noise ratio or conventional detector dose-driven exposure control in angiography: radiation dose and image quality evaluation in a porcine model. Eur Radiol Exp 2022; 6:24. [PMID: 35578057 PMCID: PMC9110612 DOI: 10.1186/s41747-022-00275-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 04/12/2022] [Indexed: 11/10/2022] Open
Abstract
Background The aim of this animal study was to compare the fluoroscopic image quality (IQ) and radiation dose between a tantalum (Ta)-specific contrast-to-noise ratio-driven exposure control (Ta-CEC) and a detector dose-driven exposure control (DEC) in abdominal angiography. Methods Nine angiography scenarios were created in seven anaesthetised pigs using Ta-based embolisation material during percutaneous liver and kidney intervention. Fluoroscopic images were acquired using three DEC protocols with different dose levels and Ta-CEC protocols with different IQ levels, sampled in small steps. Polymethyl-methacrylate and aluminium plates were used to simulate attenuation of three water equivalent thicknesses (WET). Three blinded readers evaluated the IQ of DEC and dose equivalent Ta images and selected the Ta-IQ equivalent image corresponding to the DEC image. Results Interobserver agreement for the IQ assessment was 0.43 for DEC, 0.56 for Ta-CEC and for the assessment of incident air kerma at the interventional reference point (Ka,r) for the Ta-IQ equivalent image 0.73. The average IQ of the dose equivalent Ta images was superior compared to the DEC images (p < 0.001) and also for every WET (26, 31, or 36 cm) and dose level (p ≤ 0.022). The average Ka,r for the Ta-IQ equivalent images was 59 ± 16% (mean ± standard deviation) lower compared to the DEC images (p < 0.001). Conclusions Compared to DEC, Ta-CEC significantly improved the fluoroscopic depiction of Ta, while maintaining the Ka,r. Alternatively, the Ka,r can be significantly reduced by using Ta-CEC instead of DEC, while maintaining equivalent IQ.
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Lin PJP, Goode AR, Corwin FD. Review and investigation of automatic brightness/dose rate control logic of fluoroscopic imaging systems in cardiovascular interventional angiography. Radiol Phys Technol 2022; 15:6-24. [PMID: 35050444 DOI: 10.1007/s12194-022-00649-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 01/10/2022] [Accepted: 01/11/2022] [Indexed: 11/25/2022]
Abstract
In this article, we review automatic brightness control (ABC) for fluoroscopy imaging systems. Starting from the simple manual control, the discussion is extended to the kV-primary ABC system, and then to the most recent contrast-to-noise ratio optimized (CNR Optimized) automatic dose rate control system (ADRC). The nature of this review article is trifold. First, it describes the ABC/ADRC and associated circuits governing the operation of the fluoroscopy imaging chain. Second, we show the characteristics of a control logic from a radiation physics point of view. Third, we introduce the most recent activities in the evaluation of CNR-optimized fluoroscopy systems and the phantom design that would be compatible with the design concept of the ADRC. Because of these three subject items in the discussion process, this article is also educational in nature written for medical physicists and radiological technologists who might be less familiar with the design concept of fluoroscopy operation, specifically on the ABC and ADRC. We insert a few related matters associated with fluoroscopy automatic control circuits where they seem applicable and appropriate to enhance the understanding of fluoroscopy operation logic.
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Affiliation(s)
- Pei-Jan Paul Lin
- Department of Radiology, Virginia Commonwealth University, PO Box: 980615, Richmond, VA, 23298, USA.
| | - Allen R Goode
- Department of Radiology & Medical Imaging, University of Virginia Health, PO Box 800170, Charlottesville, VA, 22908, USA
| | - Frank D Corwin
- Department of Radiology, Virginia Commonwealth University, PO Box: 980615, Richmond, VA, 23298, USA
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Monnin P, Viry A, Damet J, Nowak M, Vitzthum V, Racine D. A novel method to assess the spatiotemporal image quality in fluoroscopy. Phys Med Biol 2021; 66. [PMID: 34808602 DOI: 10.1088/1361-6560/ac3c15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 11/22/2021] [Indexed: 11/11/2022]
Abstract
Objectives. The planar formulation of the noise equivalent quanta (NEQ) and detective quantum efficiency (DQE) used to assess the image quality of projection images does not deal with the influence of temporal resolution on signal blurring and image noise. These metrics require correction factors based on temporal resolution when used for dynamic imaging systems such as fluoroscopy. Additionally, the standard NEQ and detector DQE are determined on pre-processed images in scatter-free conditions for effective energies produced by additional aluminium or copper filters that are not representative of clinical fluoroscopic procedures. In this work, we developed a method to measure 'frame NEQ' and 'frame system DQE' which include the temporal frequency bandwidth and consider the anti-scatter grid, the detector and the image processing procedures for beam qualities with scatter fractions representative of clinical use.Approach. We used a solid water phantom to simulate a patient and a thin copper disc to measure the spatial resolution. The copper disc, set in uniform rectilinear motion in the image plane, assessed the temporal resolution. These new metrics were tested on two fluoroscopy systems, a C-arm and a floor-mounted cardiology, for multiple parameters: phantom thicknesses from 5 to 20 cm, frame rates from 3 to 30 fps, spatial and temporal image processing of different weights.Main results.The frame NEQ correctly described the image quality for different scatter conditions, temporal resolutions and image processing techniques. The frame system DQE varied between 0.38 and 0.65 within the different beam and scatter conditions, and correctly mitigated the influence of spatial and temporal image processing.Significance.This study introduces and validates an unbiased formulation of in-plane NEQ and system DQE to assess the spatiotemporal image quality of fluoroscopy systems.
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Affiliation(s)
- P Monnin
- Institute of radiation physics (IRA), Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Rue du Grand-Pré 1, 1007 Lausanne, Switzerland
| | - A Viry
- Institute of radiation physics (IRA), Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Rue du Grand-Pré 1, 1007 Lausanne, Switzerland
| | - J Damet
- Institute of radiation physics (IRA), Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Rue du Grand-Pré 1, 1007 Lausanne, Switzerland.,University of Otago, Christchurch, New Zealand
| | - M Nowak
- Institute of radiation physics (IRA), Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Rue du Grand-Pré 1, 1007 Lausanne, Switzerland
| | - V Vitzthum
- Institute of radiation physics (IRA), Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Rue du Grand-Pré 1, 1007 Lausanne, Switzerland
| | - D Racine
- Institute of radiation physics (IRA), Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Rue du Grand-Pré 1, 1007 Lausanne, Switzerland
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A single phantom, a single statistical method for low-contrast detectability assessment. Phys Med 2021; 91:28-42. [PMID: 34710789 DOI: 10.1016/j.ejmp.2021.10.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 10/01/2021] [Accepted: 10/05/2021] [Indexed: 11/22/2022] Open
Abstract
PURPOSE The assessment of low-contrast-details is a part of the quality control (QC) program in digital radiology. It generally consists of evaluating the threshold contrast (Cth) detectability details for different-sized inserts, appropriately located in dedicated QC test tools. This work aims to propose a simplified method, based on a statistical model approach for threshold contrast estimation, suitable for different modalities in digital radiology. METHODS A home-madelow-contrast phantom, made of a central aluminium insert with a step-wedge, was assembled and tested. The reliability and robustness of the method were investigated for Mammography, Digital Radiography, Fluoroscopy and Angiography. Imageswere analysed using our dedicated software developed on Matlab®. TheCth is expressed in the same unit (mmAl) for all studied modalities. RESULTS This method allows the collection of Cthinformation from different modalities and equipment by different vendors, and it could be used to define typical values. Results are summarized in detail. For 0.5 diameter detail, Cthresults are in the range of: 0.018-0.023 mmAl for 2D mammography and 0.26-0.34 mmAl DR images. For angiographic images, for 2.5 mm diameter detail, the Cths median values are 0.55, 0.4, 0.06, 0.12 mmAl for low dose fluoroscopy, coronary fluorography, cerebral and abdominal DSA, respectively. CONCLUSIONS The statistical method proposed in this study gives a simple approach for Low-Contrast-Details assessment, and the typical values proposed can be implemented in a QA program for digital radiology modalities.
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Werncke T, Kemling M, Tashenov S, Hinrichs JB, Meine TC, Maschke SK, Kyriakou Y, Wacker FK, Meyer BC. Comparison of a contrast-to-noise ratio-driven exposure control and a regular detector dose-driven exposure control in abdominal imaging in a clinical angiography system. Med Phys 2021; 48:7641-7656. [PMID: 34651705 DOI: 10.1002/mp.15288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 05/28/2021] [Accepted: 09/20/2021] [Indexed: 11/05/2022] Open
Abstract
PURPOSE The first purpose of this phantom study was to verify whether a contrast-to-noise ratio (CNR)-driven exposure control (CEC) can maintain target CNR in angiography more precisely compared to a conventional detector dose-driven exposure control (DEC). The second purpose was to estimate the difference between incident air kerma produced by CEC and DEC when both exposure controls reach the same CNR. METHODS A standardized 3D-printed phantom with an iron foil and a cavity, filled with iodinated contrast material, was developed to measure CNR using different image acquisition settings. This phantom was placed into a stack of polymethylmethacrylate and aluminum plates, simulating a patient equivalent thickness (PET) of 2.5-40 cm. Images were acquired using fluoroscopy and digital radiography modes with CEC using one image quality level and four image quality gradients and DEC having three different detector dose levels. The spatial frequency weighted CNR and incident air kerma were determined. The differences in incident air kerma between DEC and CEC were estimated. RESULTS When using DEC, CNR decreased continuously with increasing attenuation, while CEC within physical limits maintained a predefined CNR level. Furthermore, CEC could be parameterized to deliver the CNR as a predefined function of PET. To provide a given CNR level, CEC used equal or lower air kerma than DEC. The mean estimated incident air kerma of CEC compared to DEC was between 3% (PET 20 cm) and 40% (PET 27.5 cm) lower in fluoroscopy and between 1% (PET 20 cm) and 55% (PET 2.5 cm) lower in digital radiography while maintaining CNR. CONCLUSION Within physical and legislative limits, the CEC allows for a flexible adjustment of the CNR as a function of PET. Thus, the CEC enables task-dependent examination protocols with predefined image quality in order to easier achieve the as low as reasonably achievable principle. CEC required equal or lower incident air kerma than DEC to provide similar CNR, which allows for a substantial reduction of skin radiation dose in these situations.
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Affiliation(s)
- Thomas Werncke
- Department of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Marius Kemling
- Department of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Stanislav Tashenov
- Advanced Therapies, Cancer Therapy, Define, Siemens Healthcare GmbH, Forchheim, Germany
| | - Jan B Hinrichs
- Department of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Timo C Meine
- Department of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Sabine K Maschke
- Department of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Yiannis Kyriakou
- Customer Services, Education, Education Architecture & Design, Siemens Healthcare GmbH, Forchheim, Germany
| | - Frank K Wacker
- Department of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Bernhard C Meyer
- Department of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
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Buytaert D, Taeymans Y, De Wolf D, Bacher K. Evaluation of a no-reference image quality metric for projection X-ray imaging using a 3D printed patient-specific phantom. Phys Med 2021; 89:29-40. [PMID: 34343764 DOI: 10.1016/j.ejmp.2021.07.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 07/06/2021] [Accepted: 07/13/2021] [Indexed: 11/19/2022] Open
Abstract
PURPOSE Feasability of a no-reference image quality metric was assessed on patient-like images using a patient-specific phantom simulating a frame of a coronary angiogram. METHODS One background and one contrast-filled frame of a coronary angiogram, acquired using a clinical imaging protocol, were selected from a Philips Integris Allura FD (Philips Healthcare, Best, The Netherlands). The background frame's pixels were extruded to a thickness proportional to their grey value. One phantom was 3D printed using composite 80% bronze filament (max. thickness of 5.1 mm), the other was a custom PMMA cast (max thickness of 8.5 cm). A vessel mold was created from the contrast-filled frame and injected with a solution of 320 mg I/ml contrast fluid (75%), water and gelatin. Still X-ray frames of the vessel mold + background phantom + 16 cm PMMA were acquired at manually selected different exposure settings using a Philips Azurion (Philips Healthcare, Best, The Netherlands) in User Quality Control Mode and were exported as RAW images. The signal-difference-to-noise-ratio-squared (SDNR2) and a spatial-domain-equivalent of the noise equivalent quanta (NEQSDE) were calculated. The Spearman's correlation of the latter parameters with a no-reference perceptual image quality metric (NIQE) was investigated. RESULTS The bronze phantom showed better resemblance to the original patient frame selected from a coronary angiogram of an actual patient, with better contrast and less blur than the PMMA phantom. Both phantoms were imaged using a comparable imaging protocol to the one used to acquire the original frame. The bronze phantom was hence used together with the vessel mold for image quality measurements on the 165 still phantom frames. A strong correlation was noted between NEQSDE and NIQE (SROCC = -0.99, p < 0.0005) and between SDNR2 and NIQE (SROCC = -0.97, p < 0.0005). CONCLUSION Using a cost-effective and easy to realize patient-specific phantom we were able to generate patient-like X-ray frames. NIQE as a no-reference image quality model has the potential to predict physical image quality from patient images.
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Affiliation(s)
- Dimitri Buytaert
- Department of Human Structure and Repair, Ghent University, Ghent, Belgium.
| | - Yves Taeymans
- Heart Center, Ghent University Hospital, Ghent, Belgium.
| | - Daniël De Wolf
- Department of Paediatric Cardiology, Ghent University Hospital, Ghent, Belgium.
| | - Klaus Bacher
- Department of Human Structure and Repair, Ghent University, Ghent, Belgium.
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Werncke T, Kemling M, Tashenov S, Hinrichs JB, Meine TC, Maschke SK, Kyriakou Y, Wacker FK, Meyer BC. Impact of a contrast-to-noise ratio driven and material specific exposure control on image quality and radiation exposure in angiography. Phys Med Biol 2021; 66:065020. [PMID: 33709957 DOI: 10.1088/1361-6560/abe83a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Conventional detector-dose driven exposure controls (DEC) do not consider the contrasting material of interest in angiography. Considering the latter when choosing the acquisition parameters should allow for optimization of x-ray quality and consecutively lead to a substantial reduction of radiation exposure. Therefore, the impact of a material-specific, contrast-to-noise ratio (CNR) driven exposure control (CEC) compared to DEC on radiation exposure was investigated. A 3D-printed phantom containing iron, tantalum, and platinum foils and cavities, filled with iodine, barium, and gas (carbon dioxide), was developed to measure the CNR. This phantom was placed within a stack of polymethylmethacrylate and aluminum plates simulating a patient equivalent thickness (PET) of 2.5-40 cm. Fluoroscopy and digital radiography (DR) were conducted applying either CEC or three, regular DEC protocols with parameter settings used in abdominal interventions. CEC protocols where chosen to achieve material-specific CNR values similar to those of DEC. Incident air kerma at the reference point(Ka,r), using either CEC or DEC, was assessed and possible Ka,r reduction for similar CNR was estimated. We show that CEC provided similar CNR as DEC at the same or lower Ka,r. When imaging barium, iron, and iodine Ka,r was substantially reduced below a PET of 20 cm and between 25 cm and 30 cm for fluoroscopy and Dr When imaging platinum and tantalum using fluoroscopy and DR and gas using DR, the Ka,r reduction was substantially higher. We estimate the Ka,r reduction for these materials between 15% and 84% for fluoroscopy and DR between 15% and 93% depending on the PET. The results of this study demonstrate a high potential for skin dose reduction in abdominal radiology when using a material-specific CEC compared to DEC. This effect is substantial in imaging materials with higher energy K-edges, which is beneficial, for example, in long-lasting embolization procedures with tantalum-based embolization material in young patients with arterio-venous malformations.
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Affiliation(s)
- Thomas Werncke
- Department of Diagnostic and Interventional Radiology, Hannover Medical School, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany
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Attanasio P, Huemer M, Kaehler N, Keller T, Schreiber T, Niehues R, Katsani-Potempa D, Klein RM, Landmesser U, Deisenhofer I, Tutdibi O, Bourier F. Safe procedures despite ultra low radiation doses during catheter ablations of atrial and ventricular arrhythmias-A multicenter experience. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2021; 44:807-813. [PMID: 33665850 DOI: 10.1111/pace.14205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 01/05/2021] [Accepted: 02/07/2021] [Indexed: 11/27/2022]
Abstract
INTRODUCTION Despite the development of non-fluoroscopic catheter visualization options, fluoroscopy is still used in most ablation procedures. The aim of this multicenter study was to evaluate the safety and efficacy of a new ultra-low dose radiation protocol for EP procedures in a large number of patients. METHODS AND RESULTS A total of 3462 consecutive patients (male 1926 (55.6%), age 64.4 ± 14.0 years, BMI 26.65 ± 4.70) undergoing radiofrequency ablation (left atrial (n = 2316 [66.9%], right atrial (n = 675 [19.5%], or ventricular (n = 471 [13.6%]) in three German centers were included in the analysis. Procedures were performed using a new ultra-low dose protocol operating at 8nGy for fluoroscopy and 36nGy for cine-loops. Additionally a very low framerate (2-3FPS) was used. Using the new protocol very low Air kerma-area product (KAP) values were achieved for left atrial ablations (104.25 ± 84.22 μGym2 ), right atrial ablations (70.98 ± 94.79 μGym2 ) and ablations for ventricular tachycardias or PVCs (78.62 ± 66.59 μGym2 ). Acute procedural success was achieved in 3289/3388 (97.1%) while the rate of major complications was very low compared to previously published studies not using low dose settings (n = 20, 0.6%). CONCLUSION The ultra-low dose, low framerate protocol leads to very low radiation doses for all EP procedures while neither procedural time, fluoroscopy time nor success or complication rates were compromised. When compared to current real-world Air KAP data the new ultra-low dose fluoroscopy protocol reduces radiation exposure by more than 90%.
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Affiliation(s)
- Philipp Attanasio
- Department of Cardiology, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
| | - Martin Huemer
- Department of Cardiology, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
| | - Nora Kaehler
- Department of Cardiology, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
| | - Theresa Keller
- Institute for Biometry and Clinical Epidemiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Tobias Schreiber
- Department of Cardiology, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
| | - Reinhard Niehues
- Augusta Krankenhaus Düsseldorf, Department of Cardiology, Academic Teaching Hospital of the University Faculty of Health, Düsseldorf, Germany
| | - Dimitra Katsani-Potempa
- Augusta Krankenhaus Düsseldorf, Department of Cardiology, Academic Teaching Hospital of the University Faculty of Health, Düsseldorf, Germany
| | - Rolf Michael Klein
- Augusta Krankenhaus Düsseldorf, Department of Cardiology, Academic Teaching Hospital of the University Faculty of Health, Düsseldorf, Germany.,Department of Cardiology, University Hospital Witten/Herdecke, Witten, Germany
| | - Ulf Landmesser
- Department of Cardiology, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
| | - Isabel Deisenhofer
- Department of Electrophysiology, German Heart Center Munich, Munich, Germany
| | - Osman Tutdibi
- Augusta Krankenhaus Düsseldorf, Department of Cardiology, Academic Teaching Hospital of the University Faculty of Health, Düsseldorf, Germany
| | - Felix Bourier
- Department of Electrophysiology, German Heart Center Munich, Munich, Germany
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Devi M, Singh S, Tiwari S. CT Image Reconstruction using NLMfuzzyCD Regularization Method. Curr Med Imaging 2021; 17:1103-1113. [PMID: 33438549 DOI: 10.2174/1573405617999210112195819] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 10/02/2020] [Accepted: 10/07/2020] [Indexed: 11/22/2022]
Abstract
Aims and scope: Computed Tomography (CT) is one of the most efficient clinical diagnostic tools. The main goal of CT is to reproduce an acceptable reconstructed image of an object (either anatomical or functional behaviour) with the help of a limited set of its projections at different angles. BACKGROUND To achieve this goal, one of the most commonly iterative reconstruction algorithm called Maximum Likelihood Expectation Maximization (MLEM) is used. OBJECTIVE Although the conventional Maximum Likelihood (ML) algorithm can achieve quality images in CT. However, it still suffers from the optimal smoothing as the number of iterations increase. METHODS For solving this problem, in this paper present a novel statistical image reconstruction algorithm for CT, which utilizes a nonlocal means fuzzy complex diffusion as a regularization term for noise reduction and edge preservation. RESULTS The proposed model was evaluated on four test cases phantoms. CONCLUSION Qualitative and quantitative analyses indicate that the proposed technique has higher efficiency for computed tomography. The proposed method yields significant improvements when compare with the state-of-the-art techniques.
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Affiliation(s)
- Manju Devi
- Deenbandhu Chhotu Ram University of Science and Technology, Murthal, Haryana,. India
| | - Sukhdip Singh
- Deenbandhu Chhotu Ram University of Science and Technology, Murthal, Haryana,. India
| | - Shailendra Tiwari
- Thapar Institute of Engineering and Technology (TIET), Patiala, Punjab,. India
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Dehairs M, Bosmans H, Leghissa M, Marshall NW. X-ray image quality and system exposure parameters for a hybrid Angio-MR system. Phys Med Biol 2020; 65:245025. [PMID: 32512547 DOI: 10.1088/1361-6560/ab9a83] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This study investigates the exposure parameters and required x-ray tube output when performing neurological procedures on a hybrid Angio-MR concept system proposed by Siemens Healthineers. The x-ray part of this system uses a longer source to detector distance than conventional (C-arm) systems and will have a fixed amount of filtration. Additionally, as the x-ray source is situated inside a magnetic field, the focal spot size and shape may be slightly distorted. In order to compare the Angio-MR system to a typical C-arm system, the exposure parameters of 60 thrombectomy procedures, performed in our hospital over the course of one year, were investigated in detail and a set of median values was determined. An analytical simulation platform was then developed to calculate the required tube voltage, tube current and pulse length to reach similar spatial frequency dependent signal difference to noise ratio (SDNR(u)) values as a conventional C-arm angiography system. These simulations were performed for a variety of focal spot sizes for the Angio-MR system. Results show that a standard current x-ray tube has sufficient power to reach similar SDNR(u) values as obtained in a conventional system if the focal spot size between both systems is comparable.
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Affiliation(s)
- M Dehairs
- UZ Gasthuisberg, Department of Radiology, Herestraat 49, 3000, Leuven, Belgium. Author to whom any correspondence should be addressed
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Dehairs M, Bosmans H, Marshall NW. A study of the impact of x-ray tube performance on angiography system imaging efficiency. ACTA ACUST UNITED AC 2020; 65:225028. [DOI: 10.1088/1361-6560/abbb7a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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15
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Yurt A, Haliloğlu RÇ, Özsoykal İ, Şişman G, Ada E. Baş-Boyun BT Anjiyografi’de Otomatik Tüp Akımı Modülasyon Sisteminin Hasta Dozu ve Görüntü Kalitesi Üzerine Etkisi. DICLE MEDICAL JOURNAL 2019. [DOI: 10.5798/dicletip.661208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Eichenlaub M, Astheimer K, Minners J, Blum T, Restle C, Maring C, Schweitzer S, Thiel U, Neumann FJ, Arentz T, Lehrmann H. Evaluation of a new ultralow-dose radiation protocol for electrophysiological device implantation: A near-zero fluoroscopy approach for device implantation. Heart Rhythm 2019; 17:90-97. [PMID: 31494091 DOI: 10.1016/j.hrthm.2019.07.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Indexed: 11/25/2022]
Abstract
BACKGROUND Radiation is one of the main hazards of electrophysiological device implantation, and insertion of cardiac resynchronization therapy (CRT) devices in particular is associated with high radiation doses. OBJECTIVE The purpose of this study was to evaluate the impact of a new ultralow-dose radiation protocol on radiation doses, success rate, and safety of electrophysiological device implantations. METHODS In 2018, we established a new ultralow-dose radiation protocol (reduced pulse width, increased thickness of minimum copper filters, reduced detector entrance dose, reduced pulse rate, optimized image postprocessing settings) for de novo device implantation at our hospital. A total of 1173 patients (11% single-chamber devices, 69% dual-chamber devices, 20% CRT devices) were analyzed. Five hundred twelve patients (44%) in the ultralow-dose group were compared to 661 patients (66%) treated during 2017 with a conventional low-dose protocol. RESULTS With the ultralow-dose radiation protocol, effective doses could be reduced by 59% (median 0.25 [interquartile range: 0.11-0.63] vs median 0.10 [interquartile range: 0.03-0.28] mSv; P <.0001) per procedure without a significant change in procedure time (P = .5). This dose reduction could be achieved without decreasing procedure success (P = 1) or increasing complication rate (P = .8). Male gender, higher body mass index, increased procedure and fluoroscopy times, and use of the conventional radiation protocol were independent predictors of higher radiation doses in multivariate regression analysis. CONCLUSION By establishing a new ultralow-dose radiation protocol, we could significantly decrease radiation exposure, reaching the lowest radiation doses for electrophysiological device implantation reported to date.
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Affiliation(s)
- Martin Eichenlaub
- Division of Cardiology and Angiology II, University Heart Center Freiburg-Bad Krozingen, Bad Krozingen, Germany.
| | - Klaus Astheimer
- Division of Cardiology and Angiology II, University Heart Center Freiburg-Bad Krozingen, Bad Krozingen, Germany
| | - Jan Minners
- Division of Cardiology and Angiology II, University Heart Center Freiburg-Bad Krozingen, Bad Krozingen, Germany
| | - Thomas Blum
- Division of Cardiology and Angiology II, University Heart Center Freiburg-Bad Krozingen, Bad Krozingen, Germany
| | - Christian Restle
- Division of Cardiology and Angiology II, University Heart Center Freiburg-Bad Krozingen, Bad Krozingen, Germany
| | - Christian Maring
- Division of Cardiology and Angiology II, University Heart Center Freiburg-Bad Krozingen, Bad Krozingen, Germany
| | - Saskia Schweitzer
- Division of Cardiology and Angiology II, University Heart Center Freiburg-Bad Krozingen, Bad Krozingen, Germany
| | - Ulrike Thiel
- Division of Cardiology and Angiology II, University Heart Center Freiburg-Bad Krozingen, Bad Krozingen, Germany
| | - Franz-Josef Neumann
- Division of Cardiology and Angiology II, University Heart Center Freiburg-Bad Krozingen, Bad Krozingen, Germany
| | - Thomas Arentz
- Division of Cardiology and Angiology II, University Heart Center Freiburg-Bad Krozingen, Bad Krozingen, Germany
| | - Heiko Lehrmann
- Division of Cardiology and Angiology II, University Heart Center Freiburg-Bad Krozingen, Bad Krozingen, Germany
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Dehairs M, Bosmans H, Marshall NW. Implementation of a spatio-temporal figure of merit for new automatic dose rate control regimes in dynamic x-ray imaging. ACTA ACUST UNITED AC 2019; 64:045001. [DOI: 10.1088/1361-6560/aafd5c] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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18
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Performance of sparse-view CT reconstruction with multi-directional gradient operators. PLoS One 2019; 14:e0209674. [PMID: 30615635 PMCID: PMC6322781 DOI: 10.1371/journal.pone.0209674] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 12/09/2018] [Indexed: 01/21/2023] Open
Abstract
To further reduce the noise and artifacts in the reconstructed image of sparse-view CT, we have modified the traditional total variation (TV) methods, which only calculate the gradient variations in x and y directions, and have proposed 8- and 26-directional (the multi-directional) gradient operators for TV calculation to improve the quality of reconstructed images. Different from traditional TV methods, the proposed 8- and 26-directional gradient operators additionally consider the diagonal directions in TV calculation. The proposed method preserves more information from original tomographic data in the step of gradient transform to obtain better reconstruction image qualities. Our algorithms were tested using two-dimensional Shepp–Logan phantom and three-dimensional clinical CT images. Results were evaluated using the root-mean-square error (RMSE), peak signal-to-noise ratio (PSNR), and universal quality index (UQI). All the experiment results show that the sparse-view CT images reconstructed using the proposed 8- and 26-directional gradient operators are superior to those reconstructed by traditional TV methods. Qualitative and quantitative analyses indicate that the more number of directions that the gradient operator has, the better images can be reconstructed. The 8- and 26-directional gradient operators we proposed have better capability to reduce noise and artifacts than traditional TV methods, and they are applicable to be applied to and combined with existing CT reconstruction algorithms derived from CS theory to produce better image quality in sparse-view reconstruction.
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Plank F, Stowasser B, Till D, Schgör W, Dichtl W, Hintringer F, Weiss G, Stühlinger M. Reduction of fluoroscopy dose for cardiac electrophysiology procedures: A feasibility and safety study. Eur J Radiol 2019; 110:105-111. [DOI: 10.1016/j.ejrad.2018.11.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 09/14/2018] [Accepted: 11/19/2018] [Indexed: 10/27/2022]
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20
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Sánchez RM, Vañó E, García LE, Fernández JM. Reducing the risk of skin injuries in cardiac catheterization procedures: Optimization proposal for obese patients. Phys Med 2018; 53:94-102. [PMID: 30241760 DOI: 10.1016/j.ejmp.2018.08.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 08/10/2018] [Accepted: 08/12/2018] [Indexed: 11/30/2022] Open
Abstract
PURPOSE During interventional cardiology procedures, high doses of X-ray may be delivered to patients. This is especially critical in cases of obese patients and/or high obliquity projections. High dose rates can then be produced in patients' skin as well as insufficient image quality due to regulatory limitations in the X-ray tube output working in the fluoroscopy mode. In this paper, an optimization action is proposed to reduce patient entrance dose rate and preserve image quality in cases of thick patients. METHODS The action is based on the evaluation of dose rate to the patient and image quality in a new fluoroscopy protocol with less frame rate (7.5 vs. 15 frames/s) and higher spectral shape filter (0.4 vs. 0.1 mm Cu). The new protocol is tested in an angiography room using a PMMA phantom and a test object. RESULTS The new fluoroscopy protocol (7.5 fr/s and 0.4 mm Cu) reduces entrance surface air kerma in 70%-10% (depending on PMMA thickness), preserving the incident air kerma per frame at the image detector. While at lower PMMA thickness, the MTF measured with bar pattern is better for the default protocol; at PMMA thickness between 32 and 37 cm, the optimized protocol produces better image quality indicators. CONCLUSIONS This work demonstrates that in the case of high thicknesses of PMMA (32-37 cm), increasing spectral beam filter and reducing frame rate may help improve image quality and maintain entrance surface air kerma so as to fulfil the regulatory requirements.
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Affiliation(s)
- Roberto M Sánchez
- Medical Physics Service, Hospital Clínico San Carlos and IdISSC, 28040 Madrid, Spain; Radiology Department, Medicine Faculty, Universidad Complutense de Madrid, 28040 Madrid, Spain.
| | - Eliseo Vañó
- Radiology Department, Medicine Faculty, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | | | - José Miguel Fernández
- Medical Physics Service, Hospital Clínico San Carlos and IdISSC, 28040 Madrid, Spain
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Hsieh CJ, Huang TK, Hsieh TH, Chen GH, Shih KL, Chen ZY, Chen JC, Chu WC. Compressed sensing based CT reconstruction algorithm combined with modified Canny edge detection. Phys Med Biol 2018; 63:155011. [PMID: 29938686 DOI: 10.1088/1361-6560/aacece] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Given that the computed tomography (CT) reconstruction algorithm based on compressed sensing (CS) results in blurred edges, we propose a modified Canny operator that assists the CS algorithm to accurately capture an object's edge, to preserve and further enhance the contrasts in the reconstructed image, thereby improving image quality. We modified two procedures of the traditional Canny operator, namely non-maximum suppression and edge tracking by hysteresis according to the characteristics of low-dose CT reconstruction, and proposed two major modifications: double-response edge detection and directional edge tracking. The newly modified Canny operator was combined with the CS reconstruction algorithm to become an edge-enhanced CS (EECS). Both a 2D Shepp-Logan phantom and a 3D dental phantom were used to conduct reconstruction testing. Root-mean-square error, peak signal-to-noise ratio, and universal quality index were employed to verify the reconstruction results. Qualitative and quantitative results of EECS reconstruction showed its superiority over conventional CS or CS combined with different edge detection techniques, such as Laplacian, Prewitt, Sobel operators, etc. The experiments verified that the proposed modified Canny operator is able to effectively detect the edge location of an object during low-dose reconstruction, enabling EECS to reconstruct images with better quality than those produced by other algorithms.
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Affiliation(s)
- Chia-Jui Hsieh
- Department of Biomedical Engineering, National Yang-Ming University, 155 Linong Street, Sec. 2, Beitou, Taipei 11221, Taiwan, People's Republic of China. Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, 155 Linong Street, Sec. 2, Beitou, Taipei 11221, Taiwan, People's Republic of China
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