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Image Quality in Cardiac Angiography

Image Quality in Cardiac Angiography. L 8.1. Educational Objectives. How can image quality of cardiac angiographic images be assessed? How useful can the quality criteria be?. Interventional cardiology in Europe 1992-1999. +112%. +204%. +75%. Rotter, EHJ 2003. 1994 1996 1999.

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Image Quality in Cardiac Angiography

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  1. Image Quality in Cardiac Angiography L 8.1

  2. Educational Objectives • How can image quality of cardiac angiographic images be assessed? • How useful can the quality criteria be? Lecture 8.1: Image quality in cardiac angiography

  3. Interventional cardiology in Europe 1992-1999 +112% +204% +75% Rotter, EHJ 2003 Lecture 8.1: Image quality in cardiac angiography

  4. 1994 1996 1999 PCI in some European Countries(1994-1999) per million 1200 2081 239 763 825 1443 242 484 267 858 800 818 Ger Fra UK Ita Nl Spa EHJ 2001, 2003 Lecture 8.1: Image quality in cardiac angiography

  5. Quality of cardiac images • background • cardiac cine-angiographic images should allow the cardiologist to evaluate the anatomic (and sometimes functional) details which are relevant for clinical decision making • variables • technical performance of the imaging system • patient cooperation • angiographic technique Lecture 8.1: Image quality in cardiac angiography

  6. the interventional cardiologist and quality… quality it’s me !! Lecture 8.1: Image quality in cardiac angiography

  7. Quality in invasive cardiology and scientific societies Scientific societies implemented guidelines to guarantee adequate level of quality and performance of invasive cardiology • training of operators • quantitative standards to maintain the expertise in coronary angiography or angioplasty • quality-assurance programme Pepine, J Am Coll Cardiol 1995;25:14–6 Miller, Can J Cardiol 1996;12:470–2 Cowley, Cathet Cardiovasc Diagn 1993;30:1–4 Heupler, Cathet Cardiovasc Diagn 1993;30:191–200 Scanlon, J Am Coll Cardiol 1999;33:1756–824 Lecture 8.1: Image quality in cardiac angiography

  8. Quality of cardiac images and scientific societies the specific problem of achieving and maintaining high-quality standards in angiographic imaging • responsibility of cardiac catheterization laboratory directors • involves periodic cine-angiograms review • lesion quantification (QCA, calipers) • precise criteria have never been stated for coronary procedures Lecture 8.1: Image quality in cardiac angiography

  9. do we need a method for image quality assessment in the routine practice of diagnostic (and interventional) cardiology ? Lecture 8.1: Image quality in cardiac angiography

  10. Types of technical deficiencies in 308 cineangiograms(Leape, Am Heart J 2000;139:106-13) N % Lecture 8.1: Image quality in cardiac angiography

  11. Percentage of inadequate studies by different hospitals (Leape, Am Heart J 2000;139:106-13) In 12/29 hosp. 50% of studies had deficencies 6 of these are teching hosp. Lecture 8.1: Image quality in cardiac angiography

  12. + 288% + 41% + 113% mean fluoroscopy time, frame number and dose-area product (DAP) in some European centers during coronary angiography Neofotistou, ER 2003 Lecture 8.1: Image quality in cardiac angiography

  13. DIMOND 3 data mean number of series projections’ distribution focus-detector mean distances Lecture 8.1: Image quality in cardiac angiography

  14. quality evaluation of angiographic imagesobjective methods based on measurement of some physical parameters • system transfer factor K • spatial resolution (MTF, modulation transfer function) • detective quantum efficiency (DQE) • noise they are rather complex and rarely applied to daily practice Lecture 8.1: Image quality in cardiac angiography

  15. quality evaluation of angiographic imagessubjective methods • test objects or phantoms • they are able to simulate the same radiation conditions as the part of the body • they describe behaviour of radiology equipment in specific operating condition • evaluation of clinical images • allow evaluation of the overall performance including patient’s collaboration and technique Lecture 8.1: Image quality in cardiac angiography

  16. test objects Lecture 8.1: Image quality in cardiac angiography

  17. quality evaluation of angiographic images clinical images produced in different conditions • binary classification • pre-defined feature identification, normal vs. abnormal (this is typically used with test objects ) • correct answer must be known • borderline visibility • progressive judgement in terms of quality • variable level quality (clarity of thoracic calcification, arrange images in order of preference) • strength of agreement by different observers gives indications on superiority Lecture 8.1: Image quality in cardiac angiography

  18. “lossy” compression 1:1 1:50 1:80 Lecture 8.1: Image quality in cardiac angiography

  19. Lecture 8.1: Image quality in cardiac angiography

  20. improper filtering proper filtering Lecture 8.1: Image quality in cardiac angiography

  21. quality evaluation of angiographic imageslimitations • set of reference images difficult to obtain • use limited settings where perceptibility of abnormal feature is under experimenter’s control • quality measurement is only relative • clinical adequacy not evaluated Lecture 8.1: Image quality in cardiac angiography

  22. quality evaluation of angiographic imagesmethod of quality criteria • quality of images is assessed in comparison to pre-specified criteria to comply with • effective and relevant in clinical practice • radiographic images (Maccia, Radiat Protect Dosim 1995; Vañò, Br J Radiol 1995, Radiat Prot Dosim 1998; Perlmutter, Radiat Prot Dosim 1998) • CT scan (Calzado, Radiat Prot Dosim 1998) Lecture 8.1: Image quality in cardiac angiography

  23. development of Quality Criteria 1995-1996: GISE Società Italiana di Cardiologia Invasiva and AIFMAssociazione Italiana di Fisica Biomedica 1996–2003: European Concerted Action DIMOND Cardiology Group(Digital Imaging: Measures for Optimizing Radiological INformation Content and Dose) contracts FI 4P-0042DG12-WSMN, FIGM-CT-2000-00061-DIMOND http://www.dimond3.org/ Lecture 8.1: Image quality in cardiac angiography

  24. Diagnostic requirementsadapted from EUR 16260 EN Image criteria In most cases specify important anatomical structures that should be visible on an image to aid accurate diagnosis. Some of these criteria depend fundamentally on correct positioning and cooperation of the patient or good angiographic technique, whereas others reflect technical performance of the imaging system Important image details Provide quantitative information on the minimum sizes at which important anatomical details should become visible on the image. Some of these anatomical details may be pathological and therefore may not be present (ex. mitral insufficiency) Lecture 8.1: Image quality in cardiac angiography

  25. Objectives • to set guidelines and give methods for the evaluation of image quality in • Left Ventriculography • Left Coronary Angiography • Right Coronary Angiography • Angiography of Venous Graft or Arterial Free Graft • Angiography of Left Mammary Artery ‘In Situ’ Model • European guidelines on quality criteria for diagnostic radiographic images (EUR 16260 EN) where the diagnostic requirementsandimage criteria are settled Lecture 8.1: Image quality in cardiac angiography

  26. What was not intended • to repeat what has already been included in the manuals of Coronary Angiography, but to give some guidelines about how an angiogram should appear provided that good equipment and a correct angiographic technique are used Warnings • under no circumstances should an image which fulfils all clinical requirements but does not meet all image criteria ever be rejected* *EUR 16260 EN Lecture 8.1: Image quality in cardiac angiography

  27. definition of terms • Clinical criteriaare defined as important anatomical features that should be visible; the level of visualisation is as follows • visualization:characteristic features are detectable, but details are not fully reproduced (features just visible) • reproduction:details of anatomical structures are visible, but not necessarily clearly defined (details emerging) • visually sharp reproduction:anatomical details are clearly defined (details clear) • Technical criteria • help to asses the technical quality of the procedure • features not necessarily impair the clinical information content (panning, arms position, etc.) • Aspects of an optimised angiographic technique • set of technical information • aimed to an optimised radiological technique • not mandatory Lecture 8.1: Image quality in cardiac angiography

  28. visualization:characteristic features are detectable, but details are not fully reproduced (features just visible) Lecture 8.1: Image quality in cardiac angiography

  29. reproduction: details of anatomical structures are visible, but not necessarily clearly defined (details emerging) Lecture 8.1: Image quality in cardiac angiography

  30. visually sharp reproduction:anatomical details are clearly defined (details clear) Lecture 8.1: Image quality in cardiac angiography

  31. clinical criteria for RCA projections based on operator’s choice 1) Visually sharp reproduction of the origin, proximal, mid (especially the crux region) and distal portion in at least two orthogonal views, with minimal foreshortening and overlap 2) Visually sharp reproduction of side branches  1.5 mm in at least two orthogonal views, with minimal foreshortening and overlap. The origin should be seen in at least one projection 3) Visually sharp reproduction of lesions in vessels  1.5 mm in at least two orthogonal views, with minimal foreshortening and overlap 4) Visualization of collateral circulation when present Lecture 8.1: Image quality in cardiac angiography

  32. technical criteria 1) Simultaneous and full opacification of the vessel lumen at least until the first flow-limiting lesion (in general ~ 90-95% by visual estimation) 2) Performed at full inspiration if necessary to avoid diaphragm superimposition or to change anatomic relationship (in apnoea in any case) 3) Arms should be raised clear of the angiographic field 4) Panning should be limited. If necessary, pan in steps rather than continuously, or make subsequent cine runs to record remote structures 5) When clinical criteria 1-4 have been fulfilled, avoid extra projections (mainly LAO semi-axial) Lecture 8.1: Image quality in cardiac angiography

  33. aspects of an optimised angiographic technique 1)Use of the wedge filter on bright peripheral areas 2)2-3 sequences (except for difficult anatomic details) 3)12.5-15 frames/s (25-30 only if heart rate exceeds 90-100 bpm or in paediatric patients) 4)60 images per sequence at average (12.5-15 fr/s) except if collaterals have to be imaged or in case of slow flow Lecture 8.1: Image quality in cardiac angiography

  34. questions on DIMOND Quality Criteria • Are these criteria, derived from a model studied for static radiological imaging, suitable for the more complex cine-angiogram examinations ? • Based on these criteria, is it possible to evaluate and quantify quality in an objective way ? Lecture 8.1: Image quality in cardiac angiography

  35. problems related to subjective evaluation of images …… Lecture 8.1: Image quality in cardiac angiography

  36. problems related to subjective evaluation of images …… Lecture 8.1: Image quality in cardiac angiography

  37. the method of image quality evaluation based on DIMOND Quality Criteria Lecture 8.1: Image quality in cardiac angiography

  38. the method of image quality evaluation based on DIMOND Quality Criteria Lecture 8.1: Image quality in cardiac angiography

  39. the method of image quality evaluation based on DIMOND Quality Criteria Lecture 8.1: Image quality in cardiac angiography

  40. example of quality score calculation (QS) for RCA Lecture 8.1: Image quality in cardiac angiography

  41.               Lecture 8.1: Image quality in cardiac angiography 

  42. example of QS calculation for RCA          sum of scores = 91(actual score) maximum theoretical score = 96 QS = actual score/theoretical score % = 65/88x100 = 94%       Lecture 8.1: Image quality in cardiac angiography 

  43. total score (mean and std dev.)15 angio, 65 readings, 3 european centers within pts variability = 0.08 Lin’s coeff = .76 (CI .67-.84) % AJC, 1999 (abs) Lecture 8.1: Image quality in cardiac angiography

  44. total score (mean and std dev.)30 angio, 160 readings, 6 european centers % Lecture 8.1: Image quality in cardiac angiography

  45. total scores compared to subjective opinion “good” and “acceptable” two cases lacking Lecture 8.1: Image quality in cardiac angiography

  46. what is ? • good I get all the information needed to treat the patient and I like this examination • acceptable I get all the information needed to treat the patientbutI don’t like very much this examination • unacceptable I don’t get all the information needed to treat the patientandI don’t like this examination at all Lecture 8.1: Image quality in cardiac angiography

  47. Remarks • the method based on Quality Criteria applies to cardiac angiography • reproducibility is good • measure of clinical acceptability seems improved in comparison to subjective opinion • the method “forces” to a systematic and standardized analysis of the images • specific training not requested (but it may improve agreement) Lecture 8.1: Image quality in cardiac angiography

  48. Quality Criteriapublished papers Criteri di Qualità dell’Immagine Cineangiografica (documento preliminare). Emodinamica 1997; 10 (suppl.): 9-11 Quality criteria of imaging in diagnostic and interventional cardiology. TCT-196: Am J Cardiol, 1999:84(6A):73P-74P A method based on DIMOND Quality Criteria to evaluate imaging in diagnostic and interventional cardiology. Radiat Prot Dosim 2001;94:167-172 Quality Criteria for cardiac images in diagnostic and interventional cardiology. Br J Radiol 2001; 74:852-855 Lecture 8.1: Image quality in cardiac angiography

  49. closing remarks • image quality is not warranted in coronary angiography • a great variability is found in common practice among different operators and radiological exposure varies considerably • image quality assessment plays a pivotal role in the optimisation of angiographic procedures • optimisation implies a continuous process of research and audit which should involve • Scientific Societies • single operators • cooperation of all professionals in the Cath. Lab. Lecture 8.1: Image quality in cardiac angiography

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