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CT ANGIOGRAPHY

CT ANGIOGRAPHY. Dr Mohamed El Safwany, MD. Intended learning outcome. The student should learn at the end of this lecture CT IMAGE OF THE BLOOD VESSEL OPACIFIED BY CONTRAST. CT IMAGE OF THE BLOOD VESSELS OPACIFIED BY CONTRAST. REQUIREMENTS FOR CTA. PATIENT PREPARATION ACQUSITION PARAMETERS

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CT ANGIOGRAPHY

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  1. CT ANGIOGRAPHY Dr Mohamed El Safwany, MD

  2. Intended learning outcome The student should learn at the end of this lecture CT IMAGE OF THE BLOOD VESSEL OPACIFIED BY CONTRAST.

  3. CT IMAGE OF THE BLOOD VESSELS OPACIFIED BY CONTRAST

  4. REQUIREMENTS FOR CTA • PATIENT PREPARATION • ACQUSITION PARAMETERS • CONTRAST MEDIUM ADMINISTRATION • POSTPROCESSING TECHNIQUES

  5. PATIENT PREP.

  6. INFORMED CONSENT

  7. PATIENT PREP. • CREAT.- 0.6 –1.2 mg/dl • IODINE ALLERGY- STEROID THERAPY • HYPERVENTILATION BEFORE EXAM FOR BETTER BREATHOLD

  8. UTILIZED

  9. GAUGE SUITABLE FOR CTA 18 OR 20

  10. CONTRAST ADMINISTERED WITH POWER INJECTOR

  11. ACQUSITION PARAMETERS

  12. PARAMETERS • USUALLY ROUTINE CT PRECEDES A CTA EXAM. THE ROUTINE EXAM IS USED AS A REFERENCE SCAN HELPING TO DETERMING THE SCANNING RANGE IN CTA.

  13. SLICE THICKNESS SPATIAL RESOLUTION SLICE THICKNESS

  14. CEREBRAL CTA ABDOMINAL CTA THORACIC CTA 1MM (LOWER mA) 3MM 3MM SLICE THICKNESS

  15. PITCH SPATIAL RESOLUTION SPIRAL PITCH

  16. SPIRAL PITCH • UP TO 2

  17. kVp, mA, TIME • SIMILAR TO NON- CTA EXAM OF THE SAME BODY PART

  18. RECONSTRUCTION INTERVAL • 50% OF OVERLAP

  19. CONTRAST ADMINISTRATION

  20. POWER INJECTOR

  21. POWER INJECTOR PARAMETERS VOLUME OF CONTRAST-ml RATE ml/sec TIME OF INJECTION – sec SCAN DELAY TIME - sec

  22. CONTRAST WARMER WHY???

  23. RATE OF INJECTION 3-5 ml/sec

  24. ORAL CONTRAST???? WATER NEGATIVE CONTRAST

  25. AUTOMATED CONTRAST ADMINISTRATION SYSTEMS • SMARTPREP • CARE • SURESTART

  26. CONTRAST ADMINISTRATION AND SCANNING METHODS • BOLUS TRACKING • BOLUS TIMING • MANUAL PRESET TIME

  27. CARE BOLUS

  28. SMART PREP

  29. Bolus tracking- PE

  30. PE?

  31. Tracking slice

  32. Bolus tracking- Carotids and Circle of Willis

  33. Circle of Willis

  34. Circle of Willis?! 40 SEC

  35. Renal arteries 25-30 sec.

  36. ABDOMINAL AND FEMORAL RUNOFF

  37. CERBRAL CTA CAROTID CTA CHEST CTA (PE) 15 SEC 12 SEC 10-20 SEC MANUAL DELAYS

  38. CARDIAC CT

  39. TWO TECHNIQUES TO REDUCE MOTION ARTIFACTS IN CARDIAC CT • PROSPECTIVE TRIGGERING • RETROSPECTIVE GATING

  40. Prospectively ECG-Triggered Sequential ScanningCardiac CT applications require the synchronization of data acquisition to the cardiac cycle, i.e. to the movement of the heart. For sequential imaging, a prospective trigger is derived from the ECG-trace to initiate the CT-scan with a certain delay time after the R-wave. Usually, the delay is defined such that the scans are acquired during the diastolic phase of the heart

  41. Retrospectively ECG-Gated Spiral ScanningFor "retrospectively ECG-gated spiral scanning" a continuous spiral scan is acquired with the ECG-signal recorded simultaneously. The acquired scan data is selected for image reconstruction with respect to a pre-defined cardiac phase. Similar to ECG-triggered sequential scanning a certain R-wave delay time defines the start point of data that is used for image reconstruction. ECG-gated spiral scanning has several advantages over ECG-triggered sequential scanning. The continuous acquisition allows for reconstruction of overlapping slices. Due to the retrospective analysis of the ECG, the technique is less sensitive to arrhythmia.

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