Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2015 Aug;5(4):524-33.
doi: 10.3978/j.issn.2223-4292.2015.04.04.

Use of 100 kV versus 120 kV in computed tomography pulmonary angiography in the detection of pulmonary embolism: effect on radiation dose and image quality

Maninderpal Kaur Gill  1 , Anushya Vijayananthan  1 , Gnana Kumar  1 , Kasthoori Jayarani  1 , Kwan-Hoong Ng  1 , Zhonghua Sun  1
Affiliations

Use of 100 kV versus 120 kV in computed tomography pulmonary angiography in the detection of pulmonary embolism: effect on radiation dose and image quality

Maninderpal Kaur Gill et al. Quant Imaging Med Surg. 2015 Aug.

Abstract

Objective: To determine the effective radiation dose and image quality resulting from 100 versus 120 kilovoltage (kV) protocols among patients referred for computed tomography pulmonary angiography (CTPA).

Methods: Sixty-six patients with clinical suspicion of pulmonary embolism (PE) were prospectively enrolled. Two CTPA protocols (group A: n=33, 100 kV/115 mAs; group B: n=33, 120 kV/90 mAs) were compared. Two experienced radiologists assessed image quality in terms of diagnostic performance and effect of artefacts. Image quality parameters [CT attenuation, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR)] and effective radiation dose between the two protocols were compared.

Results: The contrast enhancement in central and peripheral pulmonary arteries was significantly higher in group A than in group B (P<0.001) with the identical SNR (P=0.26), whereas the CNR was significantly higher in group A than in group B (P<0.001). The effective radiation dose for the 100 and 120 kV scans was 3.2 and 6.8 mSv, respectively.

Conclusions: Reducing the tube voltage from 120 to 100 kV in CTPA allows a significant reduction of radiation dose without significant loss of diagnostic image quality.

Keywords: Computed tomography pulmonary angiography (CTPA); image quality; pulmonary embolism (PE); radiation dose.

PubMed Disclaimer

Conflict of interest statement

Conflicts of Interest: The authors have no conflicts of interest to declare.

Figures

Figure 1
Figure 1
Phantom images demonstrating image quality in the standard protocol (120 kV/90 mAs) (A) and the low dose protocol (100 kV/115 mAs) (B). This is no significant difference in the spatial (i) and contrast resolution (ii) between these two protocols. kV, kilovoltage.
Figure 2
Figure 2
CTPA in mediastinal window setting (WW 400; WL 100) compares vascular enhancement at the level of main pulmonary artery (A) showing enhancement of 310.8 HU which is close to the average in 120 kV group and (B) showing a much higher enhancement of 513.5 HU that was noted in the 100 kV protocol. Circles indicate the region of interest of 1.0 cm2 (±0.5) that was used to measure the average CT number at the main pulmonary artery. CTPA, computed tomography pulmonary angiography; WW, window width; WL, window level; HU, Hounsfield unit; kV, kilovoltage.
Figure 3
Figure 3
CTPA at the level of the main pulmonary artery in two patients with pulmonary embolism compares image quality at the central and peripheral pulmonary arteries in (A) the low dose 100 kV protocol and (B) in the standard dose 120 kV protocol. Note the emboli in the segmental arteries of the lower lobes (arrows). CTPA, computed tomography pulmonary angiography; kV, kilovoltage.
Figure 4
Figure 4
Differences in the subjective assessment of image quality are demonstrated by consensus between the two protocols. The only significant difference (P value of <0.001) is seen for PAE while there is no significant difference of subjective image quality at the lung, mediastinum, and liver between the two protocols. MPA, main pulmonary artery; PAE, pulmonary artery enhancement; MA, motion artefacts.
Figure 5
Figure 5
CTPA in pulmonary artery window (WW 1,600; WL 700) in a 58-year-old male with history of sudden onset shortness of breath demonstrates filling defects at the segmental (arrows) pulmonary arteries in the 100 kV protocol in both axial (A) and coronal (B) views. CTPA, computed tomography pulmonary angiography; WW, window width; WL, window level; kV, kilovoltage.
Figure 6
Figure 6
CTPA in pulmonary artery window (WW 1,600; WL 700) in a 42-year-old male with history of cough and breathlessness shows filling defects at the segmental (arrows) pulmonary arteries in the 120 kV protocol in both axial (A) and coronal (B) views. CTPA, computed tomography pulmonary angiography; WW, window width; WL, window level; kV, kilovoltage.
See this image and copyright information in PMC

References

    1. Wittram C, Maher MM, Yoo AJ, Kalra MK, Shepard JA, McLoud TC. CT angiography of pulmonary embolism: diagnostic criteria and causes of misdiagnosis. Radiographics 2004;24:1219-38. - PubMed
    1. Remy-Jardin M, Pistolesi M, Goodman LR, Gefter WB, Gottschalk A, Mayo JR, Sostman HD. Management of suspected acute pulmonary embolism in the era of CT angiography: a statement from the Fleischner Society. Radiology 2007;245:315-29. - PubMed
    1. Perrier A, Roy PM, Sanchez O, Le Gal G, Meyer G, Gourdier AL, Furber A, Revel MP, Howarth N, Davido A, Bounameaux H. Multidetector-row computed tomography in suspected pulmonary embolism. N Engl J Med 2005;352:1760-8. - PubMed
    1. Righini M, Le Gal G, Aujesky D, Roy PM, Sanchez O, Verschuren F, Rutschmann O, Nonent M, Cornuz J, Thys F, Le Manach CP, Revel MP, Poletti PA, Meyer G, Mottier D, Perneger T, Bounameaux H, Perrier A. Diagnosis of pulmonary embolism by multidetector CT alone or combined with venous ultrasonography of the leg: a randomised non-inferiority trial. Lancet 2008;371:1343-52. - PubMed
    1. Stein PD, Fowler SE, Goodman LR, Gottschalk A, Hales CA, Hull RD, Leeper KV, Jr, Quinn DA, Sos TA, Sostman HD, Tapson VF, Wakefield TW, Weg JG, Woodard PK, PIOPED II Investigators. Multidetector computed tomography for acute pulmonary embolism. N Engl J Med 2006;354:2317-27. - PubMed