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. 2017 Sep-Oct;18(5):860-866.
doi: 10.3348/kjr.2017.18.5.860. Epub 2017 Jul 17.

Combined Electrocardiography- and Respiratory-Triggered CT of the Lung to Reduce Respiratory Misregistration Artifacts between Imaging Slabs in Free-Breathing Children: Initial Experience

Hyun Woo Goo  1 , Thomas Allmendinger  2
Affiliations

Combined Electrocardiography- and Respiratory-Triggered CT of the Lung to Reduce Respiratory Misregistration Artifacts between Imaging Slabs in Free-Breathing Children: Initial Experience

Hyun Woo Goo et al. Korean J Radiol. 2017 Sep-Oct.

Abstract

Objective: Cardiac and respiratory motion artifacts degrade the image quality of lung CT in free-breathing children. The aim of this study was to evaluate the effect of combined electrocardiography (ECG) and respiratory triggering on respiratory misregistration artifacts on lung CT in free-breathing children.

Materials and methods: In total, 15 children (median age 19 months, range 6 months-8 years; 7 boys), who underwent free-breathing ECG-triggered lung CT with and without respiratory-triggering were included. A pressure-sensing belt of a respiratory gating system was used to obtain the respiratory signal. The degree of respiratory misregistration artifacts between imaging slabs was graded on a 4-point scale (1, excellent image quality) on coronal and sagittal images and compared between ECG-triggered lung CT studies with and without respiratory triggering. A p value < 0.05 was considered significant.

Results: Lung CT with combined ECG and respiratory triggering showed significantly less respiratory misregistration artifacts than lung CT with ECG triggering only (1.1 ± 0.4 vs. 2.2 ± 1.0, p = 0.003).

Conclusion: Additional respiratory-triggering reduces respiratory misregistration artifacts on ECG-triggered lung CT in free-breathing children.

Keywords: Children; ECG triggering; Lung CT; Motion artifacts; Respiratory triggering.

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Conflict of interest statement

Conflict of Interest: Thomas Allmendinger is a Siemens Healthcare employee.

Figures

Fig. 1
Fig. 1. Schematic drawing of combined ECG and respiratory triggering.
From ECG leads, R wave (dot) is detected and end-systolic phase (arrows) is determined by trigger delay. Pressure-sensing belt is placed in upper abdomen to continuously monitor respiratory signal; in this case, respiratory triggering (dot) is produced at inspiration peak. When they occur concurrently, these two triggering signals can be passed through gate box to CT system. Combined ECG and respiratory triggering at R wave on ECG (dot) is displayed on CT console. From combined ECG and respiratory triggering, end-systolic sequential scanning is acquired every three R waves in this case. ECG = electrocardiography
Fig. 2
Fig. 2. Measurement of respiratory misregistration artifacts between imaging slabs on sagittal formatted lung CT image.
Respiration misregistration occurred at three levels and degree of misregistration was measured in length (brackets) at six locations. Among them, maximal length (Max, orange yellow bracket) was used for semi-quantitative grading (grade 1, < 2 mm; grade 2, 2–5 mm; grade 3, 5–10 mm; and grade 4, > 10 mm).
Fig. 3
Fig. 3. 5-year-old boy with Langerhans cell histiocytosis.
A, B. Free-breathing coronal (A) and sagittal (B) ECG-triggered lung CT images acquired at end-systole show grade 4 respiratory misregistration artifacts. C, D. Respiratory misregistration artifacts grade was grade 1 on free-breathing coronal (C) and sagittal (D) lung CT images with combined ECG and respiratory triggering at end-systole and inspiration peak.
Fig. 4
Fig. 4. 2-year-old girl with multifocal congenital pulmonary airway malformation.
Free-breathing axial (A), coronal (B), and sagittal (C) lung CT images with combined ECG and respiratory triggering at end-systole and expiration peak demonstrate excellent normal anatomic and pathologic details without any motion artifacts.
See this image and copyright information in PMC

References

    1. Montaudon M, Berger P, Blachère H, De Boucaud L, Latrabe V, Laurent F. Thin-section CT of the lung: influence of 0.5-s gantry rotation and ECG triggering on image quality. Eur Radiol. 2001;11:1681–1687. - PubMed
    1. Ha HI, Goo HW, Seo JB, Song JW, Lee JS. Effects of high-resolution CT of the lung using partial versus full reconstruction on motion artifacts and image noise. AJR Am J Roentgenol. 2006;187:618–622. - PubMed
    1. Schoepf UJ, Becker CR, Bruening RD, Helmberger T, Staebler A, Leimeister P, et al. Electrocardiographically gated thin-section CT of the lung. Radiology. 1999;212:649–654. - PubMed
    1. Nishiura M, Johkoh T, Yamamoto S, Honda O, Kozuka T, Koyama M, et al. Electrocardiography-triggered high-resolution CT for reducing cardiac motion artifact: evaluation of the extent of ground-glass attenuation in patients with idiopathic pulmonary fibrosis. Radiat Med. 2007;25:523–528. - PubMed
    1. Kalender WA, Rienmüller R, Seissler W, Behr J, Welke M, Fichte H. Measurement of pulmonary parenchymal attenuation: use of spirometric gating with quantitative CT. Radiology. 1990;175:265–268. - PubMed