achenbach
TRANSCRIPT
Fast CT Angiography on a Fast Track to Your
Practice: Promises and Limitations
S. AchenbachDepartment of Radiology, Massachusetts General Hospital
Department of Cardiology, University of Erlangen
Coronary artery imaging:
- small diameters (~1-4 mm)
- complex anatomy
- rapid motion
CT Techniques
- High spatial resolution
- Good contrast
- Problem: temporal resolution
Electron Beam Tomography (EBT)
50 - 100 ms image acquisition time1.5 mm - 3.0 mm slice thickness
Electron Beam Tomography (EBT)
CT coronary imaging feasible
Limitations: 1.5 -3.0 mm slice thickness
X-ray power
„e-Speed“: 1.5 mm slice thickness
50 ms temporal resolution
Multislice spiral CT with retrospective ECG gating- Tube rotation: 420-500 ms- Data acquisition in 4-16 slices simultaneously
- Partial scan reconstruction using ~ 210-250 ms
4 slice CT: ~1.3 mm slices 16 slice CT: ~0.75 mm slices
MSCT 4 Slice
EBT
MSCT 16 slice
MSCT 16 slice
MSCT 16 slice
MSCT 16 slice
MSCT 16 slice
n Sens. Spec. n.e.
Schmermund JACC 1998 28 82% 88% 12%Reddy Radiology 1998 23 88% 79% 8%Achenbach N Engl J Med 1998 125 92% 94% 25%Ropers Z Kardiol 2000 118 90% 82% 24%Achenbach Heart 2000 36 92% 91% 20%
Nieman Lancet 2001 31 81% 97% 27%Achenbach Circulation 2001 64 91% 84% 32% Knez Am J Cardiol 2001 42 78% 98% 6%Kopp Eur Heart J 2002 102 86% 96% 16%Becker JCAT 2003 28 78% 71% 11%Nieman Heart 2002 53 82% 93% 30%
Nieman Circulation 2002 59 95% 86% 7%Ropers Circulation 2003 77 93% 92% 12%
MSCT:
Heart Rate < 60/min desirable:
oral ß-blockade to all patients
EBT/MSCT:
Coronary calcium
LIMITATIONS:Contrast, radiationSinus rhythmUnevaluable arteriesAccuracy = 100%
Diagnostic tool with high negative predictive value (~95%) if image quality is sufficient
CT to replace cardiac cath?
„A man with a hammer sees a lot of things that need to be hammered.“
(A radiologist/cardiologist with a spiral CT ...)
Clinical Indications for MSCT?
... Not for screening
... Not in patients with typical symptoms
... Possibly in patients with relatively low likelihood of signficant stenosis (atypical symptoms, equivocal stress test ...)
> 20% „rule out“ coronary angiograms
100 patients prior to valve surgery: All 36 patients with stenoses identified by EBT. 54 patients: stenoses ruled out.
Anomalous coronary arteries
Bypass Grafts:
EBT 4-slice MSCT 16 slice MSCT
Nieman et al, Circulation 2002
STENT?
Detection of Plaque
4- slice MSCT
Schröder et al. JACC 2001
Detection of Plaque
16-slice MSCT
Detection of Plaque
Potential role in risk assessment?
- Accuracy / Quantification?
- Reproducibility?
- Progression over time?
- Prognostic value?
„Fast CT Coronary Angiography“:- Technical issues
Heart rate, technology, protocols
- „Coronary Angiography“
Potential role to rule out stenoses
- „Plaque imaging“?
(Potential role for risk stratification)