Comparison of Dual- and Single-Source Dual-Energy CT for Diagnosis of Acute Pulmonary Artery Embolism

Abstract

Purpose Comparison of dual-source dual-energy CT (DS-DECT) and split-filter dual-energy CT (SF-DECT) regarding image quality and radiation dose in patients with suspected pulmonary embolism.

Materials and Methods We retrospectively analyzed pulmonary dual-energy CT angiography (CTPA) scans performed on two different CT scanners in 135 patients with suspected pulmonary embolism (PE). Scan parameters for DS-DECT were 90/Sn150 kV (n = 68 patients), and Au/Sn120 kV for SF-DECT (n = 67 patients). The iodine delivery rate was 1400 mg/s in the DS-DECT group vs. 1750 mg/s in the SF-DECT group. Color-coded iodine distribution maps were generated for both protocols. Objective (CT attenuation of pulmonary trunk [HU], signal-to-noise ratio [SNR], contrast-to-noise ratio [CNR]) and subjective image quality parameters (two readers [R], five-point Likert scale), as well as radiation dose parameters (effective radiation dose, size-specific dose estimations [SSDE]) were compared.

Results All CTPA scans in both groups were of diagnostic image quality. Subjective CTPA image quality was rated as good or excellent in 80.9 %/82.4 % (R1 / R2) of DS-DECT scans, and in 77.6 %/76.1 % of SF-DECT scans. For both readers, the image quality of split-filter iodine distribution maps was significantly lower (p < 0.05) with good or excellent ratings in only 43.3 %/46.3 % (R1 / R2) vs. 83.8 %/88.2 % for maps from DS-DECT. The HU values of the pulmonary trunk did not differ between the two techniques (p = n. s.), while both the SNR and CNR were significantly higher in the split-filter group (p < 0.001; p = 0.003). Both effective radiation dose (2.70 ± 1.32 mSv vs. 2.89 ± 0.94 mSv) and SSDE (4.71 ± 1.63 mGy vs. 5.84 ± 1.11 mGy) were significantly higher in the split-filter group (p < 0.05).

Conclusion The split-filter allows for dual-energy imaging of suspected pulmonary embolism but is associated with lower iodine distribution map quality and higher radiation dose.

Key points: 

• The split-filter allows for dual-energy data acquisition from single-source single-layer CT scanners.

• Compared to the assessed dual-source dual-energy system, split-filter dual-energy imaging of a suspected pulmonary embolism is associated with lower iodine distribution map quality and higher radiation dose.

• Both the split-filter and the dual-source scanner provide diagnostic image quality in CTPA.

Citation Format

• Petritsch B, Pannenbecker P, Weng AM et al. Comparison of Dual- and Single-Source Dual-Energy CT for Diagnosis of Acute Pulmonary Artery Embolism. Fortschr Röntgenstr 2021; 193: 427 – 436

Zusammenfassung

Ziel Vergleich von Dual-Source-Dual-Energy-CT (DS-DECT) und Split-Filter-Dual-Energy-CT (SF-DECT) hinsichtlich objektiver und subjektiver Bildqualitätsparameter und Dosisexposition bei Patienten mit Verdacht auf eine Lungenarterienembolie (LAE).

Material und Methoden Es wurden 135 Patienten, welche bei Verdacht auf eine LAE eine pulmonale Dual-Energy-CT-Angiografie (CTPA) erhielten, in die retrospektive Studie eingeschlossen. Die Scan-Parameter waren 90/Sn150 kV beim DS-DECT- (n = 68 Patienten) und Au/Sn120 kV beim SF-DECT-System (n = 67 Patienten). Die Jod-Injektionsrate betrug 1400 mg/s in der DS-DECT-Gruppe vs. 1750 mg/s in der SF-DECT. Farbkodierte Jod-Distributionskarten wurden für beide Protokolle berechnet. Es wurden die objektive (CT-Abschwächung im Truncus pulmonalis (HU), Signal-Rausch-Verhältnis (SNR), Kontrast-Rausch-Verhältnis (CNR)) und subjektive Bildqualität (2 Auswerter (R), 5-Punkte-Likert-Skala) sowie Dosisparameter (effektive Dosis, größenspezifische Dosiseinschätzungen (SSDE)) erhoben und verglichen.

Ergebnisse In beiden Gruppen waren alle CTPAs von diagnostischer Qualität. Die subjektive Bildqualität der CTPA wurde in 80,9/82,4 % (R1 / R2) der DS-DECT und in 77,6 %/76,1 % der SF-DECT als gut oder exzellent bewertet. Die Qualität der Jod-Distributionskarten der DS-DECT wurde in 83,8/88,2 % als gut oder exzellent bewertet. Beide Auswerter bewerteten die Qualität der Jod-Distributionskarten der SF-DECT signifikant niedriger (p < 0,05), wobei nur in 43,3/46,3 % (R1 / R2) eine gute oder exzellente Qualität vorlag. Die HU-Werte im Truncus pulmonalis waren zwischen beiden Gruppen ähnlich (p = n. s.), während SNR und CNR in der Split-Filter-Gruppe signifikant höher waren (p < 0,001; p = 0,003). Sowohl die effektive Dosis (2,70 ± 1,32 mSv vs. 2,89 ± 0,94 mSv) als auch die SSDE (4,71 ± 1,63 mGy vs. 5,84 ± 1,11 mGy) waren in der Split-Filter-Gruppe signifikant höher (p < 0,05).

Schlussfolgerung Bei Verdacht auf eine Lungenembolie ermöglicht der Split-Filter eine Dual-Energy-Untersuchung an Single-Source-CT-Scannern, ist aber mit einer schlechteren Qualität der Jod-Distributionskarten und einer höheren Dosisexposition vergesellschaftet.

Kernaussagen: 

• Der Split-Filter ermöglicht eine Dual-Energy-Datenakquisition an Single-Source-Single-Layer-CT-Scannern.

• Verglichen mit dem untersuchten Dual-Source-Dual-Energy-System ist die pulmonale Split-Filter-Dual-Energy-CT mit einer schlechteren Qualität der Jod-Distributionskarten und einer höheren Dosisexposition vergesellschaftet.

• Sowohl der Split-Filter als auch der Dual-Source-Scanner ermöglichen eine CTPA in diagnostischer Bildqualität.

Key words

CT-angiography - dual-energy - pulmonary embolism - image quality - radiation dose

• References

• 1 Tapson VF. Acute pulmonary embolism. N Engl J Med 2008; 358: 1037-1052
• 2 Remy-Jardin M, Pistolesi M, Goodman LR. et al. Management of suspected acute pulmonary embolism in the era of CT angiography: a statement from the Fleischner Society. Radiology 2007; 245: 315-329
• 3 Konstantinides SV, Torbicki A, Agnelli G. et al. 2014 ESC guidelines on the diagnosis and management of acute pulmonary embolism. Eur Heart J 2014; 35: 3033-3069, 3069a–3069k
• 4 Stein PD, Fowler SE, Goodman LR. et al. Multidetector Computed Tomography for Acute Pulmonary Embolism (PIOPEDII). N Engl J Med 2006; 354: 2317-2327
• 5 Weidman EK, Plodkowski AJ, Halpenny DF. et al. Dual-Energy CT Angiography for Detection of Pulmonary Emboli: Incremental Benefit of Iodine Maps. Radiology 2018; 289: 546-553
• 6 Ota M, Nakamura M, Yamada N. et al. Prognostic significance of early diagnosis in acute pulmonary thromboembolism with circulatory failure. Hear Vessel 2002; 17: 7-11
• 7 McCollough CH, Leng S, Yu L. et al. Dual- and Multi-Energy CT: Principles, Technical Approaches, and Clinical Applications. Radiology 2015; 276: 637-653
• 8 Johnson TRC. Dual-energy CT: general principles. Am J Roentgenol 2012; 199: 3-8
• 9 Petritsch B, Kosmala A, Gassenmaier T. et al. Diagnosis of Pulmonary Artery Embolism: Comparison of Single-Source CT and 3^rd Generation Dual-Source CT using a Dual-Energy Protocol Regarding Image Quality and Radiation Dose. Rofo 2017; 189: 527-536
• 10 Pontana F, Faivre JB, Remy-Jardin M. et al. Lung Perfusion with Dual-energy Multidetector-row CT (MDCT). Feasibility for the Evaluation of Acute Pulmonary Embolism in 117 Consecutive Patients. Acad Radiol 2008; 15: 1494-1504
• 11 Fink C, Johnson TR, Michaely HJ. et al. Dual-energy CT angiography of the lung in patients with suspected pulmonary embolism: initial results. Rofo 2008; 180: 879-883
• 12 Bauer RW, Kerl JM, Weber E. et al. Lung perfusion analysis with dual energy CT in patients with suspected pulmonary embolism--influence of window settings on the diagnosis of underlying pathologies of perfusion defects. Eur J Radiol 2011; 80: 476-482
• 13 Thieme SF, Graute V, Nikolaou K. et al. Dual Energy CT lung perfusion imaging--correlation with SPECT/CT. Eur J Radiol 2012; 81: 360-365
• 14 Apfaltrer P, Sudarski S, Schneider D. et al. Value of monoenergetic low-kV dual energy CT datasets for improved image quality of CT pulmonary angiography. Eur J Radiol 2014; 83: 322-328
• 15 Siegel MJ, Kaza RK, Bolus DN. et al. White Paper of the Society of Computed Body Tomography and Magnetic Resonance on Dual-Energy CT, Part 1. J Comput Assist Tomogr 2016; 40: 841-845
• 16 Rutt B, Fenster A. Split-filter computed tomography: a simple technique for dual energy scanning. J Comput Assist Tomogr 1980; 4: 501-509
• 17 Euler A, Parakh A, Falkowski AL. et al. Initial Results of a Single-Source Dual-Energy Computed Tomography Technique Using a Split-Filter: Assessment of Image Quality, Radiation Dose, and Accuracy of Dual-Energy Applications in an In Vitro and In Vivo Study. Invest Radiol 2016; 51: 491-498
• 18 Almeida IP, Schyns LEJR, Öllers MC. et al. Dual-energy CT quantitative imaging: a comparison study between twin-beam and dual-source CT scanners. Med Phys 2017; 44: 171-179
• 19 Boone JM, Strauss KJ, Cody DD. et al Size-Specific Dose Estimates In Pediatric and Adult Body CT Examinations: Report No. 204. Am. Assoc. Phys. Medcine, Coll. Park 2011; ISBN: 978-1-936366-08-8
• 20 Sullivan GM, Artino AR. Analyzing and Interpreting Data From Likert-Type Scales. J Grad Med Educ 2013; 5: 541-542
• 21 Euler A, Obmann MM, Szucs-Farkas Z. et al. Comparison of image quality and radiation dose between split-filter dual-energy images and single-energy images in single-source abdominal CT. Eur Radiol 2018; 28: 3405-3412
• 22 May MS, Wiesmueller M, Heiss R. et al. Comparison of dual- and single-source dual-energy CT in head and neck imaging. Eur Radiol 2018; 29: 4207-4214
• 23 Kaemmerer N, Brand M, Hammon M. et al. Dual-Energy Computed Tomography Angiography of the Head and Neck With Single-Source Computed Tomography: A New Technical (Split Filter) Approach for Bone Removal. Invest Radiol 2016; 51: 618-623
• 24 Große Hokamp N, Maintz D, Shapira N. et al. Technical background of a novel detector-based approach to dual-energy computed tomography. Diagn Interv Radiol 2020; 26: 68-71
• 25 Siegel MJ, Kaza RK, Bolus DN. et al. White Paper of the Society of Computed Body Tomography and Magnetic Resonance on Dual-Energy CT, Part 1: Technology and Terminology. J Comput Assist Tomogr 2016; 40: 841-845
• 26 Schoepf UJ, Goldhaber SZ, Costello P. Spiral computed tomography for acute pulmonary embolism. Circulation 2004; 109: 2160-2167
• 27 Bauer RW, Schell B, Beeres M. et al. High-pitch dual-source computed tomography pulmonary angiography in freely breathing patients. J Thorac Imaging 2012; 27: 376-381
• 28 Schenzle JC, Sommer WH, Neumaier K. et al. Dual energy CT of the chest: how about the dose?. Invest Radiol 2010; 45: 347-353
• 29 Bauer RW, Kramer S, Renker M. et al. Dose and image quality at CT pulmonary angiography-comparison of first and second generation dual-energy CT and 64-slice CT. Eur Radiol 2011; 21: 2139-2147
• 30 Yu L, Primak AN, Liu X. et al. Image quality optimization and evaluation of linearly mixed images in dual-source, dual-energy CT. Med Phys 2009; 36: 1019-1024
• 31 Sauter AP, Shapira N, Kopp FK. et al. CTPA with a conventional CT at 100 kVp vs’. a spectral-detector CT at 120 kVp: Comparison of radiation exposure, diagnostic performance and image quality. Eur J Radiol Open 2020; 7: 100234
• 32 Tabari A, Gee MS, Singh R. et al. Reducing Radiation Dose and Contrast Medium Volume With Application of Dual-Energy CT in Children and Young Adults. Am J Roentgenol 2020; 214: 1199-1205
• 33 Thieme SF, Becker CR, Hacker M. et al. Dual energy CT for the assessment of lung perfusion – correlation to scintigraphy. Eur J Radiol 2008; 68: 369-374
• 34 Okada M, Kunihiro Y, Nakashima Y. et al. Added value of lung perfused blood volume images using dual-energy CT for assessment of acute pulmonary embolism. Eur J Radiol 2015; 84: 172-177
• 35 Sueyoshi E, Tsutsui S, Hayashida T. et al. Quantification of lung perfusion blood volume (lung PBV) by dual-energy CT in patients with and without pulmonary embolism: preliminary results. Eur J Radiol 2011; 80: e505-e509