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Nuclear Cardiology Guidelines

Nuclear Cardiology Guidelines. Benchmark to compare local practice against. UK Guidelines. British Nuclear Cardiology Society British Nuclear medicine Society British Cardiac Society http://www.bnms.org.uk Draft - Rev 3 2002 21 pages. USA (1) - SNM. Society of Nuclear Medicine

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Nuclear Cardiology Guidelines

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  1. Nuclear Cardiology Guidelines Benchmark to compare local practice against

  2. UK Guidelines • British Nuclear Cardiology Society • British Nuclear medicine Society • British Cardiac Society • http://www.bnms.org.uk • Draft - Rev 3 2002 • 21 pages

  3. USA (1) - SNM • Society of Nuclear Medicine • Version 2.0 • 1999 • http://www.snm.org • 14 pages

  4. USA (2) - ASNC • American Society of Nuclear Cardiology • Two part guidelines (1998-2000) • http://www.asnc.org • 84 close-typed pages

  5. Techniques Covered  = Covered in detail  = Mentioned

  6. MPI – SPECT: Aspects Covered

  7. Doses (MBq) Boost for obese pt?   FDA max

  8. Stress Methods • Methods • Exercise (treadmill or bike) • Pharmacological • Adenosine • Dipyridamole • Dobutamine • Contraindications • Stop conditions

  9. Acquisition • LEHR parallel hole collimator • Circular or non-circular orbit • 20% symmetric energy window • 64 x 64 or 128 x 128 (optional) • Zoom can be used • Take care heart always in view (BNCS) • Pixel size • around 6mm (BNCS) 6.4±0.2 mm (ASNC) • cf Picker 4.9mm (64*64,1.8mag) • imaging time 20-30 min • Continuous or S&S with 32/64 stops

  10. Processing: stages and options

  11. Motion Correction • All guidelines state that patient motion should be assessed • SNM gives acceptable limits: ±1 pixel in axial direction in a 64x64 study • Repeat acquisition or optionally use software methods for minor motion

  12. Filtering - ASNC • Not prescriptive • Discusses filter types • “Conventional” • Butterworth/Hamming/Hanning • “Restorative” / “Contrast Enhancement” • Wiener/Metz • For gated, recommend “0.55 or 0.45 Nyquist frequency cutoff” for Butterworth • Iterative reconstruction an option if available

  13. Filtering - BNCS “Filtered back projection using Butterworth and Hanning filters is the most common method of reconstruction. Cut-off frequencies of 0.5 and 0.75 respectively are normally chosen, and these should be the same for each patient and should not be altered to compensate for low-count images in order to maintain consistency of appearance. Iterative reconstruction is preferred if attenuation correction has been performed and it can also be used without attenuation correction.”

  14. Attenuation Correction (Transmission sources) • Attenuation correction methods “in rapid development”..“difficult to provide ‘cookbook’ guidelines” (ASNC) • “The effectiveness of these techniques in routine clinical practice is currently uncertain. They should currently be used only in experienced centres and preferably as part of a formal evaluation of their value” (BNCS)”

  15. Reformatting & Display • SA / HLA / VLA slices • Stress and rest with frames aligned or interactive manipulation • Report from computer display (not hardcopy) • A “continuous” colour scale (BNCS) • NO guidance on combining adjacent slices

  16. Normalisation of frames • Each set of tomograms should be displayed using a window maximum that corresponds to the maximum within the myocardium in each set. Displays that set the maximum of the window to the maximum of each tomogram and those that use the same maximum for stress and rest images should not be used. (BNCS) • “Preferred” ..”frame normalization” ..normalized to the brightest pixel in each frame. That method provides optimal image quality of each slice. Drawback..gradations in activity between slices in a series may be lost. (ASNC)

  17. Quantification • ASNC guidelines detail semi-quantitative segmental “scoring” systems • Full quantification (QGS etc) • Mentioned briefly in ASNC and BNCS • Always as a supplement to visual analysis • May have benefits for inexperienced observers and for serial comparison of studies

  18. Report Contents • Patient Details • Indications • Stress • agent / dose / protocol / response /ECG changes • Study Quality • Findings • Ventricular dilatation, Lung Uptake • Perfusion defects (severity/extent/“reversibility”) • Conclusion • Prognosis / recommendations

  19. Sources of error • Submaximal stress • Inadequate dose for BMI • Acquisition • Poor positioning/orbit, Wrong energy window • Patient motion, Attenuation artefacts • Reconstruction and processing • Inappropriate filter / reconstruction technique • Wrong alignment • Image display • Inappropriate colour scale or windowing • Comparison of inappropriate frames/slices

  20. Conclusion • Lots of useful information • Not a complete “cookbook” - still lots of scope for differences that may affect final result, especially in processing and display • Local audit may have value

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