Imaging Pearls ❯ Dual Energy ❯ Thoracic Applications
|
-- OR -- |
|
- “A thoracic vascular imaging protocol was achievable using lower kilovoltage (80 vs. 100 kVp), lower contrast volume (75 vs. 100 mL), and a slower delivery (3 mL/s vs. 4 mL/s), and still resulted in better vascular attenuation,comparable CNR, and reduced radiation exposure.Inherent to this advantage are cost savings in relation to the utilization of contrast media, but also the potential reduction of contrast dose shown and, hence, contrast induced nephropathy in patients with existing renal impairment.”
Dual-energy Computed Tomography Imaging of the Aorta
Vlahos I, Godoy MCB, Naidich DP
J Thorac Imaging 2010;25:289–300 - “Virtual noncontrast images are slightly noisier in their appearance with regard to noncontrast images, as they are susceptible to noise in the constituent 80- and 140-kVp
images from which they are derived. However, the images are diagnostic, as their intended purpose is to identify preexisting high-attenuation structures or areas.”
Dual-energy Computed Tomography Imaging of the Aorta
Vlahos I, Godoy MCB, Naidich DP
J Thorac Imaging 2010;25:289–300 - “Image reconstruction at a lower monochromatic energy level (50keV) allows for a 50% reduction in iodine load at CT pulmonary angiography (CTPA) while maintaining signal intensity and diagnostic image quality.”
Reduced Iodine Load at CT Pulmonary Angiography with
Dual-Energy Monochromatic Imaging: Comparison with StandardCT Pulmonary Angiography—A Prospective Randomized Trial
Yuan R et al.
Radiology 2012;262:290-297 - “In summary, we conclude projection based dual-energy monochromatic imaging enables significant reduction in iodine load CTPA while maintaining
compatible SNR, CNR, and effective radiation dose.”
Reduced Iodine Load at CT Pulmonary Angiography with
Dual-Energy Monochromatic Imaging: Comparison with StandardCT Pulmonary Angiography—A Prospective Randomized Trial
Yuan R et al.
Radiology 2012;262:290-297
- “ Dual-energy CT can offer a “one-stop” assessment of anatomy and perfusion in CTEPH. The additional information provided by dual-energy CT could have a future role in helping guide patient selection for thromboendarterectomy surgery.”
Dual-Energy CT Angiography for Assessment of regional Pulmonary Perfusion in Patients with Chronic Thromboembolic Pulmonary Hypertension
Hoey ETD et al.
AJR 2011; 196:524-532 - “ A strong correlation existed between dual energy CT derived perfusion and mosaic attenuation pattern when both lobar and whole lung scores were assessed.”
Dual-Energy CT Angiography for Assessment of regional Pulmonary Perfusion in Patients with Chronic Thromboembolic Pulmonary Hypertension
Hoey ETD et al.
AJR 2011; 196:524-532 - Dual Energy Technology
- Dual source CT: 2 x-ray tubes run at different kVps so data is perfectly aligned
- Single source CT: rapid kVp switching is needed to get the two series aligned
- Imaging at Lower kVp (80 or 100 kvp vs 120 or 140 kVp): The Bad News
- Increase in image noise
- MPR and 3D quality made be limited
- Imaging at Lower kVp (80 or 100 kvp vs 120 or 140 kVp): The Good News
- Iodinated contrast shows an approximately 80% increase in CT attenuation at 80 kVp compared with 140 kVp
- Lower radiation dose
- Less IV contrast needed for select examinations
- Reduction in artifacts like pseudoenhancement
- What is Dual Energy CT?
"Material decomposition at dual energy CT can differentiate renal stones by their composition, quantify tissue iron stores, improve the detection of pathologic hyperenhancement, and reduce contrast material and radiation dose compared with conventional CT."
Dual-Energy and Low-kVp CT in the Abdomen
Yeh BM et al.
AJR 2009; 193:47-54 - What is Dual Energy CT?
"Low peak tube voltage (kVp) settings provide high conspicuity of contrast materials at CT but may result in high image noise, particularly in larger patients."
Dual-Energy and Low-kVp CT in the Abdomen
Yeh BM et al.
AJR 2009; 193:47-54 - What is Dual Energy CT?
The use of dual energy in a CT scan is to help create a new technique for data acquisition and display in order to optimize data extraction from complex datasets. Goals include data display, analysis and post processing.