LightSpeed VCT XT

LightSpeed VCt XT evaluation system

Coronary CTA Exam in less than 1 second of X-ray exposure and at 1.1 mSv

JL. Sablayrolles, J. Feignoux, JM. Treutenaere, MD, Centre Cardiologique du Nord, Saint-Denis, France

Case study

Patient history


Figure 1: Heart in Volume Rendering.

Figure 1: Heart in Volume Rendering.

A Coronary CTA exam (Figures 1 & 2) was requested in order to evaluate the coronary arteries of a 48 year-old man (1.5 m, 46 kg, BMI = 20.4) with risk factors (high cholesterol, family history and smoking), and atypical angina.


Technique

The exam was performed on the LightSpeed VCT XT® evaluation system and the Snapshot Pulse™ feature.
Scan parameters were optimized considering the morphology, the age of the patient and the indication of the exam. The dose delivered during the examination was 1.1mSv*. The total exposure time was 0.7sec with a scan time of 5 seconds.


Scan parameters:

  • 64-slice detector
  • Slice thickness: 0.625 mm
  • Rotation time: 0.35 second
  • 550 mA, 100 kVp
  • Coverage: 104 mm
  • Heart rate: 59 bpm
  • Total X-Ray exposure time : 0.7 second


Injection protocol:

Three phase injection using a dual head injector

  • 80 ml of iodine contrast @ 5 cc/sec
  • 30 ml of contrast media @ 2cc/sec
    + 30 ml of isotonic solution @ 2cc/sec
  • 20 ml of saline flush @ 2.5 cc/sec
  • Iodine concentration: 300 mg/ml


Dose:

  • DLP : 66 mGy.cm
  • Dose: 1.1 mSv*


Result

Coronary assessment


Figure 2-1: Coronary tree in Angiographic view and Volume Rendering.

Figure 2: Coronary tree in Angiographic view and Volume Rendering.


Figure 2-2

Figure 2-2


Figure 2-3

Figure 2-3


On the left side, the Left Main Trunk (LMT) is short but of normal aspect.
The Left Anterior Descending (LAD) artery demonstrates a long and moderate stenosis of non-calcified plaque in segment I (Figures 3, 4 & 5) estimated at 40%. A small calcification without any stenosis is seen distal to the previous one. The rest of the LAD and its diagonal branches are of normal aspect.


Figure 3: Curved view of the LAD.

Figure 3: Curved view of the LAD.


Figure 4: Curved view of the LAD.

Figure 4: Curved view of the LAD.


Figure 5: X-section view of the LAD, segment I, demonstrating the soft plaque.

Figure 5: X-section view of the LAD, segment I, demonstrating the soft plaque.


Figure 6: Curved views of the LMB.

Figure 6: Curved views of the LMB.

The Left Circumflex (LCx) artery is restricted to a Left Marginal Branch (LMB) that is normal (Figure 6).


The Right Coronary Artery (RCA), the Postero Lateral Branch (PLB) and the Posterior Descending Artery (PDA) are also normal without significant stenosis (not shown).


Conclusion

The coronary CT exam revealed a moderate stenosis of non-calcified plaque spread along the LAD segment I in a 48-year-old patient with risk factors and atypical angina.

For this patient, the GE exclusive Snapshot Pulse™ feature was used and the scan parameters were optimized in order to perform a low radiation dose examination. With this new scanning technology, the diagnosis was achieved with an excellent image quality at only 1.1 mSv*. Total X-Ray exposure time was only 0.7 second.



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