Medical Imaging and Radiotherapy Journal (MIRTJ) 39 (Suppl. 1) 7 Medical Imaging and Radiotherapy Journal (MIRTJ) 39 (Suppl. 1) PREDNOSTI IN SLABOSTI DVOSPEKTRALNE CTA PLJUČNIH ARTERIJ V PRIMERJAVI Z ENOSPEKTRALNO CTA PLJUČNIH ARTERIJ ADVANTAGES AND DISADVANTAGES OF DUAL-ENERGY PULMONARY CTA COMPARED TO SINGLE ENERGY PULMONARY CTA Aleš Kaučič 1, Hana Žitnik 2 1 Univerzitetni klinični center Ljubljana, Klinični inštitut za radiologijo, Zaloška cesta 7, 1000 Ljubljana, Slovenija / University medical centre Ljubljana, Institute of Radiology, Zaloška cesta 7, 1000 Ljubljana, Slovenia 2 Univerzitetna Klinika za pljučne bolezni in alergijo Golnik, Oddelek za diagnostično in intervencijsko radiologijo, Golnik 36, 4204 Golnik, Slovenija / University Clinic Golnik, The Department of Diagnostic and Interventional Radiology, Golnik 36, 4204 Golnik, Slovenia. Korespondenca / Corresponding author: ales.kaucic@gmail.com Prejeto/Recived: 11. 1. 2022 Sprejeto/Accepted: 3. 3. 2022 IZVLEČEK Uvod in namen: Primerjali smo razliko v dozi (CTDIvol in DLP) med dvospektralno (DE) CTA pljučnih arterij in klasično enospektralno (SE) CTA pljučnih arterij in razliko med atenuacijskimi vrednostmi v pljučnih arterijah. Na praktičnih primerih smo izpostavili razlike v tehnični izvedbi ter opisali prednosti in slabosti dvospektralnega slikanja. Metode: Retrospektivno smo primerjali 90 preiskav, narejenih na napravi Dual Source CT Siemens Somatom Drive; ena skupina SE CTA z avtomatsko izbiro kV (Care kV) in druga skupina DE CTA z nastavitvijo 80/Sn140 kV in 100/Sn140 kV pri pacientih z višjim ITM. Pri vseh DE CTA smo s programom syngo.via naredili monoenergijske rekonstrukcije. Radiolog je pri vseh preiskavah v pljučnih arterijah izmeril atenuacijske vrednosti in preiskave ocenil kot diagnostične ali ne- diagnostične s kriterijem minimalno 250 HU v pljučnem deblu. S programom IBM SPSS Statistics v.25 smo naredili Shapiro- Wilkov test normalnosti in t-test neodvisnih vzorcev; rezultati kažejo normalno porazdelitev vseh vzorcev. Rezultati: Med vzorcema ni bilo statistično pomembne razlike v ITM (p = 0,056). Povprečna vrednost CTDIvol pri SE CTA je bila 4,2 mGy, pri DE CTA 5,8 mGy. Povprečna vrednost DLP pri SE CTA je bila 130,6 mGy.cm, pri DE CTA 182,6 mGy.cm. Vrednosti so nižje od priporočenih DRL vrednosti (13 mGy za CTDIvol in 440 mGy.cm za DLP). Opazili smo statistično pomembno razliko v CTDIvol (p < 0,001) in DLP vrednosti (p < 0,001) s povprečno 38,1 % povišanjem CTDIvol in 39,8 % povišanjem DLP pri DE CTA glede na povprečje SE CTA. V skupini SE CTA so bile 3 preiskave ocenjene kot ne-diagnostične, v skupini DE CTA so bile vse preiskave ocenjene kot diagnostične. Povprečne HU vrednosti v pljučnem deblu so bile pri SE CTA 547,8 HU, pri DE CTA 519,5 HU, pri monoenergijskih rekonstrukcijah 1553,9 HU. Med SE CTA in DE CTA ni bilo statistično pomembne razlike v HU vrednosti (p = 0,564). Statistično pomembna razlika v HU vrednostih je bila med SE CTA in monoenergijskih rekonstrukcijah (p < 0,001) in med DE CTA in monoenergijskih rekonstrukcijah (p < 0,001). Razprava in zaključek: Ugotovili smo, da je pri DE CTA v povprečju doza višja kot pri SE CTA. Pri vseh DE CTA preiskavah smo pri monoenergijskih rekonstrukcijah opazili občutno povišanje HU vrednosti in izboljšan prikaz pljučnih arterij. Glavna pomanjkljivost DE CTA je v našem primeru lastnost DSCT naprave. Zaradi manjšega slikovnega polja kakovostna DE CTA ni izvedljiva pri pacientih z visokim ITM. DE CTA je kljub višji dozi dobra alternativa klasični SE CTA, ker ponuja izdelavo novih vrst rekonstrukcij z občutnim izboljšanjem prikaza pljučnih arterij, rekonstrukcij za izboljšan prikaz pljučnega intersticija in rekonstrukcij za prikaz perfuzije pljuč. Hkrati je z možnostjo ustvarjanja monoenergijskih rekonstrukcij DE CTA pljučnih arterij možno izvesti z nižjo količino jodnega kontrastnega sredstva. Ključne besede: dvospektralni CT, pljučna embolija, angiografi ja 8 Medical Imaging and Radiotherapy Journal (MIRTJ) 39 (Suppl. 1) Medical Imaging and Radiotherapy Journal (MIRTJ) 39 (Suppl. 1) ABSTRACT Introduction and purpose: We compared the diff erence in dose (CTDIvol and DLP) between dual-energy (DE) Pulmonary CTA and single-energy (SE) pulmonary CTA, and the diff erence in attenuation values measured in the pulmonary truncus. Methods: In a retrospective study we compared 90 examinations performed on the same dual source CT scanner Siemens Somatom Drive; one group SE pulmonary CTA with automated kV adjustment (Care kV), the second group DE pulmonary CTA with 80/Sn140 kV and 100/Sn140 kV settings for patients with higher BMI. With syngo.via software we reconstructed monoenergetic images in all DE CTA examinations. A radiologist measured HU values in the pulmonary truncus in all examinations and assessed whether the examination is diagnostic with a minimal cut off value of 250 HU. We performed a Shapiro-Wilk test to test for normality and independent samples t-tests with the IBM SPSS Statistics v.25 programme. Results: There was no statistically signifi cant diff erence in BMI between both groups (p=0.056). The average measured CTDIvol values were 4.2 mGy for SE CTA and 5.8 mGy for DE CTA. The average DLP values were 130.6 mGy.cm for SE CTA and 182.6 mGy.cm for DE CTA. All values were below the published DRLs recommendation (13 mGy for CTDIvol and 440 mGy.cm for DLP respectively). There was a statistically signifi cant diff erence in CTDIvol (p < 0.001) and DLP (p < 0.001) values with an average 38.1% increase in CTDIvol and a 39.8% increase in DLP values for DE CTA compared to average values for SE CTA. In the SE CTA group 3 examinations were assessed as non-diagnostic, in the DE CTA group all examinations were assessed as diagnostic. The average HU values measured in the pulmonary truncus were 547.8 HU for SE CTA, 519.5 HU for DE CTA and 1553.9 HU for monoenergetic images. There was no statistically signifi cant diff erence in HU values between SE CTA and DE CTA (p=0.564). There was a statistically signifi cant diff erence in HU values between SE CTA an monoenergetic images (p < 0.001), and between DE CTA and monoenergetic images (p < 0.001). Conclusion: We concluded that DE CTA is accompanied with an increased dose penalty, compared to SE CTA. Monoenergetic images assessed from the DE CTA examinations showed greatly increased HU values and improved pulmonary artery depiction. Despite higher dose values, DE CTA is a good alternative to SE CTA owing to high HU values in monoenergetic images, which enhances pulmonary artery depiction and reduces the chance of a non-diagnostic examination. Keywords: dual energy computed tomography, pulmonary embolism, angiography LITERATURA / REFERENCES Albrecht M, Bickford M, Nance J et al. (2017). State-of-the- Art Pulmonary CT Angiography for Acute Pulmonary Embolism. American Journal of Roentgenology 208: 495- 504. doi: 10.2214/AJR.16.17202 Apfaltrer P, Sudarski S, Schneider D et al. (2014). Value of monoenergetic low-kV dual energy CT datasets for improved image quality of CT pulmonary angiography. European Journal of Radiology. Volume 83: 322-328. Chen T, Xiao H (2019). 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