State-of-the-art Cardiac CT of the coronary arteries


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Presentation given at Arab Health congress on Jan. 29th 2013, with information about (dual source) Cardiac CT of the coronary arteries with technical & practical information and some clinical use cases

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State-of-the-art Cardiac CT of the coronary arteries

  1. 1. Cardiac CTE. R. RanschaertRadiologist Arab Health Congress, Jan 28-31, 2013
  2. 2. Introduction Technical aspects Scanning procedure Indications for c-CTA Clinical cases  64 slice  dual source CT Copyright E. R. Ranschaert
  3. 3. Coronary CTA Main purpose: morphology  Detection and analysis of coronary artery disease  Depict anatomy of coronary vasculature Possible to obtain functional information in same scan  contractility of myocardium  valve morphology and function  “viability” of myocardium (perfusion-CT) Copyright E. R. Ranschaert
  4. 4. Technicalaspects
  5. 5. Multislice CT - MDCT Evolution of Cardiac CT is strongly linked to technical improvements in CT- scanners Preferably 64-slice scanner or more Our current machine: dual source CT 2x64 slice (Somatom Definition Flash) Other vendors: 256-slice or higher Copyright E. R. Ranschaert
  6. 6. Volume coverage – helical scan  Time to cover heart decreases with larger detector arrays, shorter tube rotation times and faster table movement 4 x 1 mm slice 16 x 1mm slices 64 x 0.5 mm slices 4 mm 16 mm 32 mm ~48 sec ~12 sec ~6 sec Copyright E. R. Ranschaert 0.5 s rotation, 0.33 pitchCourtesy of Sue Edyvean, ImPACT –
  7. 7. “Old” generation scanners 16-slice 64-sliceImages used with permission of James Carr, MD Copyright E. R. Ranschaert
  8. 8. Newer generation scannersComplete coverage High pitch Toshiba Acquilion Siemens Definition FlashSeq 256-slice, spiral 64-slice 2x 64 slice single rotation fast pitch, no gaps Copyright E. R. Ranschaert Courtesy of Sue Edyvean, ImPACT –
  9. 9. Multi-sector scanning Min. 2 sectors needed per imageGraphics used with permission of Sue Edyvean, ImPACT – Copyright E. R. Ranschaert
  10. 10. Multi-sector scanning GE Philips Siemens Siemens Toshiba 1 tube 2 tubes# sectors 1,2,4 up to 5 1 or 2 1 or 2 up to 5Graphics used with permission of Sue Edyvean, ImPACT – Copyright E. R. Ranschaert
  11. 11. Dual source CT (0,285 s rotation for entire heart)Graphics used with permission of Sue Edyvean, ImPACT – Copyright E. R. Ranschaert
  12. 12. FLASH-CTVolume-rendered MPR - normal LAD Copyright E. R. Ranschaert
  13. 13. Scanningprocedure
  14. 14. Patient Preparation General CT-preparation:  Renal function, hydration, stop Metformin if GFR<60, premedication for iodine allergy Specific cardiac-CT preparation:  Information sheet specifically for cardiac CT  Beta-blockers: P.O. (in advance)  Other premedication if needed Copyright E. R. Ranschaert
  15. 15. Day of scanning 3-4 h in advance: no meal, no coffee, no tea 2h in advance 25-100 mg metoprolol P.O. (selective β1 receptor blocker) Fine tuning HR with IV injection, 5-20 mg extra Selection of scan protocol depending on bpm variability For Flash: ≤65 bpm and regular HR needed Copyright E. R. Ranschaert
  16. 16. ECG monitoring on scan ECG monitoring is used to “freeze” cardiac motion Images made during phase of least cardiac motion Phase is given as % of R-R interval Courtesy of Sue Edyvean, ImPACT – Copyright E. R. Ranschaert
  17. 17. Scanning Breath hold on ¾ of full inspiration (prevents Valsalva manoeuvre) Breathing instructions are practiced with patient before scanning Nitroglycerine spray immediately before scanning 1 puff Contrast (high iodine concentration) is injected at 5-6 ml/sec Copyright E. R. Ranschaert
  18. 18. Stable HR needed Motion needs to be repeatable – regular heart rate  reduce potential for mis-registration  applies for both axial and helical iiiii iiiii iiiii ECG Copyright E. R. Ranschaert
  19. 19. MisregistrationStairstep artefacts Copyright E. R. Ranschaert
  20. 20. Calcium scoring First calcium score is determined low dose non-enhanced triggered scan Semi-automated calculation of score Decision to make c-CTA based upon score and age  Score 0 >60j: no cCTA  >600: no cCTA Copyright E. R. Ranschaert
  21. 21. Selection CTA scan protocol 3 acquisition modes with ECG synchronisation 1. Retrospective gating 2. Prospective triggering = sequential/axial = “adaptive sequence” (Siemens) 3. FLASH = prospective triggering spiral scan with very high pitch Copyright E. R. Ranschaert
  22. 22. 1. Retrospective gating  Spiral scan technique  Small overlapping pitch ≅ 0,2  Heart scanned in all phases  Breath hold = 7-12 sec  Retrospective selection of best phase for reconstruction/reviewing  Functional information  10-12 mSvCourtesy of Sue Edyvean, ImPACT – Copyright E. R. Ranschaert
  23. 23. Cardiac CT – ECG phases  Optimal phase for reconstruction for CTA  diastole @ ~ 70 % Optimal reconstruction phase R R 70% R-R Eg. 50 60 70 80Courtesy of Sue Edyvean, ImPACT –R. Ranschaert Copyright E.
  24. 24. 2. Prospective triggering  ACS: Adaptive Cardio Sequence  Sequential technique  ECG-signal is used to trigger scanning (R-wave)  “Padding” opens scan pulse (30-80% RR)  With “padding” more phases are available for review (steps of 1 – 20%)  Dose reduction up to 87% compared with retrospective scanning (2,5 - 3 mSv)  Usable in patients with slightly irregular heart beatCourtesy of Siemens: Thomas Flohr, Cardiac CT Acquisition modes Copyright E. R. Ranschaert
  25. 25. Triggering  R wave recognised - scan triggered Radiation on (and attenuation data acquired)Courtesy of Sue Edyvean, ImPACT – Copyright E. R. Ranschaert
  26. 26. Management of extrasystoles Selection Low / Medium / High protocol depends on HR (60-85 bpm) ACS makes analysis of ECG, ectopic heart beats are detected Start of scan is prospectively based upon last 3 cycles Scan is omitted & delayed when extrasystole is detected before scan Scan is repeated when extrasystole occurs during or shortly after scan Flex padding uses extended acquisition window: gives more flexibility to find optimal reconstruction phase Copyright E. R. Ranschaert
  27. 27. Copyright E. R. Ranschaert Padding „padding‟ for CTA Radiation on(and attenuationdata acquired) 480° rotation
  28. 28. Copyright E. R. Ranschaert Padding „padding‟ for CTA Radiation on(and attenuationdata acquired) 70 Required data for image recon.
  29. 29. Copyright E. R. Ranschaert Padding  Axial scanning with „padding‟  More flexibility with reconstructed phase position „padding‟ for CTA Radiation on(and attenuationdata acquired). 60 Required data for image recon.
  30. 30. Copyright E. R. Ranschaert Padding  Axial scanning with „padding‟  More flexibility with reconstructed phase position „padding‟ for CTA Radiation on(and attenuationdata acquired). Required data for image recon.
  31. 31. 3. Flash – single beat, high pitch • 2 Sectors of data acquired simultaneously in ¼ rotation = 75 ms • Whole heart in 3¼ rotations = 0,28 sec • No misregistration, no stair-step artefacts: 1 shot!Copyright E. R. Ranschaert Courtesy Siemens
  32. 32. Which protocol to use?  RETROSPECTIVE:  Only with patients that are not suited for prospective scanning due to arythmia, high HR or both  If functional imaging is needed (LVA)  PROSPECTIVE:  Stable and low HR  Slight arythmia  With ACS: 65-85 bpm  Low – medium – high protocol  Also LVA possible with adaptive sequence (padding)  Use Flash whenever possible!SCCT guidelines on radiation dose and dose-optimization strategies in cardiovascular CT,Halliburton SS et al., J Cardiovasc Computed Tomogr (2011)5, 198-224 Copyright E. R. Ranschaert
  33. 33. Indications
  34. 34. Indications for c-CTA Calcium scoring  Risk stratification  Decisive before CTA examination Coronary CTA  Anatomy of coronary vessels (CAG difficult)  CAD (low to intermediate risk)  Stent viability  Anatomy and patency of grafts after CABG Functional analysis Copyright E. R. Ranschaert
  35. 35. Calcium scoring “Gatekeeper” for further cardiac examination if pre-test probability is low and EST is not possible Added value in risk stratification (re- stratification of medium risk) With men and female >60y score = 0 is very reassuring (high NPV) Copyright E. R. Ranschaert
  36. 36. Assessment of stenoses Visual assessment Significant (obstructing) is > 50% Non-significant or non- obstructive < 50% Resolution vs. CAG: 20% margin is taken Non-obstructing stenosis Significant stenosis into account Copyright E. R. Ranschaert
  37. 37. Limitations of cCTAIrregular HRobesitystents < 3 mmCalcium and stents: “blooming” artefacts lower specificity of cCTA Copyright E. R. Ranschaert
  38. 38. Copyright E. R. Ranschaert Blooming Artefact  Blooming artefact – calcium/stent obscures vessel  Improvement with better spatial resolution Improved spatial resolution and display (recon alg., fov) 49 Courtesy of Sue Edyvean, ImPACT –
  39. 39. Copyright E. R. Ranschaert Diagnostic accuracy of cCTA  CAG is gold standard cCTA  Ideally patients with stable HR + stable AP complaints Sens 96-99% or atypical chest pain  Very useful to exclude Spec 88-91% significant CAD: high NPV NPV >90% Low to intermediate risk patiënts
  40. 40. Anatomy Left main stemRCA AM PDA Cx Diag branch LAD Copyright E. R. Ranschaert
  41. 41. Functional assessment Copyright E. R. Ranschaert
  42. 42. Clinical cases64-slice
  43. 43. Case 1 F, 43y Atypical precordial complaints EST-test negative Copyright E. R. Ranschaert
  44. 44. Case 2 F, 68y Chest pain Pain after exercise stress testing, ECG normal Copyright E. R. Ranschaert
  45. 45. cCTA: extensive CAD with short occlusion RCAAdvise to perform CAG Copyright E. R. Ranschaert
  46. 46. Copyright E. R. Ranschaert
  47. 47. Copyright E. R. Ranschaert
  48. 48. Case 3 M, 33y SEH left thoracic pain irradiation to left arm CAG: no significant stenoses demonstrated, “catheter spasm” In history probably limited myocardial infarction cCTA performed 3m later Copyright E. R. Ranschaert
  49. 49. yright E. R. Ranschaert Non-stenosing non-calcified plaque in prox. circumflex artery
  50. 50. Case 4 M, 43j Chest pain, arm pain while painting during 30 min Normal EST, ECG normal cCTA Copyright E. R. Ranschaert
  51. 51. Case 4 Chronically occluded RCA ectatic coronary system Copyright E. R. Ranschaert
  52. 52. RCA Reinjection via left systemCopyright E. R. Ranschaert
  53. 53. Non-calcified plaque“ectatic” LAD Copyright E. R. Ranschaert
  54. 54. Case 5  Woman, 1967  Atypical precordial pain PA Ao  Cycling test negative  Low risk PA RCA AoCopyright E. R. Ranschaert
  55. 55. Anomalous RCA  Anomalous RCA arising from left sinus of valsalva AA PA  Most common pathway for ectopic RCA RCA  Associated with sudden cardiac death in 30% of pts  Dilatation of Ao duringRCA PA excercise comprises RCA, may lead to AMI inter-arterial course of RCA Ao Copyright E. R. Ranschaert
  56. 56. Ao RCA PACopyright E. R. Ranschaert
  57. 57. Anatomic variant  Left CA main branch: origin posterior on AA  from non-coronary sinus of Valsalva  Retro-aortic course  Usually no clinical relevance LA D CxCopyright E. R. Ranschaert
  58. 58. Case studiesdual-source
  59. 59. Case 2 flash Male, 56 y Chest pain (AP-complaints) ECG doubtful Hypertension High cholesterol Copyright E. R. Ranschaert
  60. 60. Copyright E. R. Ranschaert
  61. 61. Case 3Copyright E. R. Ranschaert
  62. 62. Ostial aneurysm RCA Copyright E. R. Ranschaert
  63. 63. Post CABG 64-slice scan 3 venous grafts Occluded Patency grafts? Only graft to RCA open Open Copyright E. R. Ranschaert
  64. 64. Origin of LAD graft not Start scan high visualised enough! Cx graft Copyright E. R. Ranschaert
  65. 65. Post-CABG Male, 81y CAG was performed:  Graft from AO to LAD could not be visualised  prox. occlusion? Copyright E. R. Ranschaert
  66. 66. Cx graft: patent RCA graft: occluded proximally Copyright E. R. Ranschaert
  67. 67. Case 4 78y-old female patient Previous CABG Unstable AP Dialysis patient CAG unsuccessful: LIMA not visualised Dual source CT, retrospective scanning Copyright E. R. Ranschaert
  68. 68. FindingsLIMA 3D LIMA 2D Copyright E. R. Ranschaert
  69. 69. Findings case 4LIMA – LAD anastomosis Distal LAD Stenosis Copyright E. R. Ranschaert
  70. 70. Case 5 History Calcium scoring Female, 1963 Referred by GP for atypical chest pain, dyspnea with effort Bicycle ergometry: not conclusive ECG mild abnormalities Copyright E. R. Ranschaert
  71. 71. Case 6 cCTA Flash mode MIPCopyright E. R. Ranschaert
  72. 72. Case 6LAD LADCopyright E. R. Ranschaert
  73. 73. Case 6 – stent evaluation Pre-stenting Post-stenting Copyright E. R. Ranschaert
  74. 74. Case 6: stent evaluation Stent LAD Diagonal branch Copyright E. R. Ranschaert
  75. 75. Case 7 Female, 51 y Dyspnoea with effort, fatigue, no chest pain FA: father sudden death at 55y, probably AMI ECG normal Copyright E. R. Ranschaert
  76. 76. Case 7 RCA Non-calcified stenosis 70%Copyright E. R. Ranschaert
  77. 77. The End Thank you!