SOMATOM Sessions - Siemens Healthcare

Clinical Results Cardio-Vascular
Case 4
Pre-operative Exclusion of Coronary
Artery Stenosis With Less Than 1 mSv Dose
By Sebastian Leschka, MD* and Andreas Blaha**
* Institute of Diagnostic Radiology, University Hospital Zurich, Zurich, Switzerland
**
Business Unit CT, Siemens Healthcare, Forchheim, Germany
HISTORY
A 71-year-old male patient with a history
of cerebral infarction caused by a highgrade
stenosis of the left internal carotid
artery and lysis therapy was now referred
to the radiology department to
rule out coronary artery disease.
In addition to the coronary CT Angiography
(CTA) examination a non-enhanced
calcium-scoring scan (CaSc)
was performed.
The CTA was acquired with a fast pitch
spiral technique (Flash Spiral Cardio)
while a mean heart rate of 56 bpm was
present.
DIAGNOSIS
Threshold = 130 HU (102.7 mg/cm 3 CaHA)
In total, ten calcified lesions could be
detected in the CaSc. Diffuse distribution
of calcified deposits was observed in
the right coronary artery (RCA), the left
artery descending (LAD) and the left circumflex
coronary artery (CX). The total
Agatston score was 130.
CTA unveiled a normal coronary artery
anatomy, right dominant coronary supply
type with regular sized lumen of the
coronary arteries. RCA and LAD showed
no hemodynamic relevant lesions. CX
coronary artery unveiled a stenosis
smaller than 50% in its proximal segment.
A deep myocardial bridging of the
LAD could also be depicted.
38 SOMATOM Sessions · May 2010 · www.siemens.com/healthcare-magazine
COMMENTS
In combination with the CaSc (0.35 mSv)
and the CTA (0.8 mSv), an effective
dose* of 1.1 mSv was applied to the
patient to detect coronary artery disease.
The entire acquisition time of the CTA
was 280 ms; calcium scoring was
acquired in 120 ms.
The Flash Spiral cardio method quickly
and reliably combines low radiation
dose values with the accurate display of
the coronary arteries in all segments.
Artery Numbers of Calcium Score (2) Volume [mm 3 ] (3) Equiv. Mass
Lesions (1) [mg CaHA] (4)
LM 0 0.0 0.00 0.0
LAD 2 27.5 29.3 4.89
CX 3 48.3 50.5 8.57
RCA 5 53.6 66.2 10.81
Total 10 129.5 146.0 24.27
(1) Lesion is volume based, (2) Equivalent Agatston score, (3) Isotropic interpolated volume, (4) Calibration Factor: 0.790
*Effective Dose was calculated using the published conversion factor for an adult chest of 0.014 mSv (mGy cm) -1 [1].
[1] McCollough CH et al. Strategies for Reducing Radiation Dose in CT, Radiol. Clin. N. Am. 47: (2009) 27-40.