Image Quality and Dose Comparison of Single-Energy CT (SECT) and Dual-Energy CT (DECT)

Abstract

CT and its comprehensive usage have become one of the most indispensable components in medical field especially in the diagnosis of several diseases. SECT and DECT have developed CT diagnostic potentials in several means. In this review article we have discussed the basic principles of single-energy and dual-energy computed tomography and their important physical differences which can cause better diagnostic evaluation. Moreover, different organs diagnostic evaluations through single-energy and dual-energy computed tomography have been discussed. Conventional or single-energy CT (SECT) uses a single polychromatic X-ray beam (ranging from 70 to 140 kVp with a standard of 120 kVp) emitted from a single source and received by a single detector. The concept of dual-energy computed tomography (DECT) is almost as old as the CT technology itself; DECT initially required substantially higher radiation doses (nearly two times higher than those employed in single-energy CT) and presented problems associated with spatial misregistration of the two different kV image datasets between the two separate acquisitions. The basic principles of single-energy and dual-energy computed tomography and their important physical differences can cause better diagnostic evaluation. Moreover, different organs diagnostic evaluations through single-energy and dual-energy computed tomography have been discussed. According to diverse data and statistics it is controversial to definitely indicate the accurate comparison of image quality and dose amount.

Figure 1

CTDIvol and DLP comparison. The comparison of CTDIvol and DLP factor between patients with the mean age 58 ± 17 years through DECT and SECT in head and neck. All numbers are mean ± SD mGy [32].

Figure 2

Axial contrast-enhanced images of neck. DE WA images; (a) SE image (b). Both in 120 kv [32].

Figure 3

Measurement of CTDIv. CTDIv measurement through head of a 10-year-old patient in both SECT and DECT [33].

Figure 4

Liver metastasis from gastric carcinoma. SECT scan. (a) CTDIvol = 10.00. (b) DECT scan obtained 57 days after (a) for both mean kv is 90 [34].

Figure 5

CNR, SNR, and CTDIv. Comparison of CNR, SNR, and CTDIv (mSv) in both SECT and DECT in liver [34].

Figure 6

CNR, SNR, and CTDIv. Comparison of CNR, SNR, and CTDIv (mSv) in both SECT and DECT in abdomen [36].

Figure 7

DECT and SECT of abdomen. Abdominal 120 kV second generation. (a) Effective dose adjusted for standard 40 cm acquisition length was 6.5 mSv. Images from a second-generation dual-energy CT (DECT) study in a 58-year-old male with a BMI of 26.5 kg/m² demonstrating extensive ascites (arrows). (b) Adjusted effective dose was 7.0 mSv [36].

Figure 8

Measurement of CTDIv. CTDIv measurement through abdomen of a 10-year-old patient in both SECT and DECT [33].

Figure 9

SECT and virtual noncontrast comparison. Single-energy image series before administration of intravenous contrast media. (a) A virtual noncontrast series from the dual-energy contrast-enhanced images. (b) kv used in this examination is 120 [43].

Figure 10

Comparison of image quality between SECT urinary and DECT VNC. It is clear that image quality in DECT virtual noncontrast is greater than SECT urinary [43].

Figure 11

Image quality of DECT and SECT through beam hardening artifact volume. Image quality comparison of surgical group who are undergoing intracranial aneurysm repair with the factor of beam hardening artifact volume and its scale is ml [44].

Figure 12

Comparison of DLP in SECT and DECT. Radiation dose comparison of surgical group who are undergoing intracranial aneurysm repair with the factor of DLP and its scale is mGy [44].

Figure 13

DE-CTA and SE-CTA. Axial and coronal DE-CTA (a) and SE-CTA (b) kv is 100/Sn140 and mAs is 111 [44].

Figure 14

Cardiac magnetic resonance imaging (cMRI) and dual-energy computed tomography (DECT) imaging of myocardial infarction. Iodine color map reconstructed from a DECT image demonstrates good agreement when compared with delayed enhancement cMRI of a subject with prior myocardial infarction of the lateral wall. Similar to cMRI, DECT offers the potential to assess myocardial infarction as well as myocardial salvage through the use of pre- and postcontrast techniques [45].