European Journal of Radiology 70 (2009) 579–588 MDCT angiography for detection of pulmonary emboli: Comparison between equi-iodine doses of iomeprol 400 mgI/mL and iodixanol 320 mgI/mL Herbert Langenberger a,∗ , Klaus Friedrich a , Christina Plank a , Wolfgang Matzek a , Florian Wolf a , Maria Luigia Storto b , Cornelia Schaefer-Prokop c , Christian Herold a a Department of Radiology, Vienna General Hospital, Medical University, Waehringer Guertel 18-20, A-1090 Vienna, Austria b Department of Radiology, University of Chieti, Chieti, Italy c Amsterdam Medish Centrum, University of Amsterdam, Amsterdam, Netherlands Received 24 October 2007; received in revised form 8 January 2008; accepted 14 January 2008 Abstract Objectives: To compare iomeprol 400 and iodixanol 320 in pulmonary artery MDCTA in subjects with suspected pulmonary embolism. Methods: Eighty randomized subjects received equi-iodine intravenous doses (48 g) of iomeprol 400 (n = 40) or iodixanol 320 (n = 40), via power injector at 4mL/s. Four-row (35 subjects) and 64-row (45 subjects) scanners were used. Lumen attenuation was determined on-site and by two off-site blinded readers in the main, lobar, segmental and subsegmental pulmonary arteries. Statistical comparison between groups was performed for demographics and lumen attenuation. Results: There were no between-group differences (p > 0.05) in demographics. Pulmonary artery attenuation was significantly (p ≤ 0.03) higher with iomeprol 400 for all readers. Attenuation quality was excellent in more patients after iomeprol 400 than after iodixanol-320 (80% vs. 62.5%; 82.5% vs. 77.5%; off-site readers 1 and 2, respectively). No safety concerns were noted. Conclusion: The greater iodine delivery rate achievable with iomeprol 400 compared to iodixanol-320 at equi-iodine dose and injection rate permits consistently greater attenuation at all levels of the pulmonary arterial tree. © 2008 Published by Elsevier Ireland Ltd. Keywords: Computed tomography (CT), angiography; Computed tomography (CT), contrast enhancement; Contrast media, comparative studies; Pulmonary arteries, CT; Embolism, pulmonary 1. Introduction Multi-slice computed tomography (MSCT) is now the tech- nique of choice for detection of suspected pulmonary emboli (PE) [1–12]. The possibility to perform MSCT angiography of the entire pulmonary arterial vasculature within a single short breath-hold, and to obtain high spatial resolution with visualiza- tion down to the fifth- and sixth-order pulmonary arteries, results in excellent sensitivity and specificity for the detection of PE [2]. The technique is considered sufficiently robust and reproducible to have served as the reference standard in a study to determine ∗ Corresponding author. Tel.: +43 1 40400 5827; fax: +43 1 4953828. E-mail address: Herbert.langenberger@meduniwien.ac.at (H. Langenberger). the diagnostic accuracy of MR imaging for the diagnosis of PE [13]. To date, many studies have utilized contrast agents (CA) with iodine concentrations ranging between 300 [3–6] and 350 mgI/mL [9,10]. Typically, 100–120mL of CA are injected at flow rates of 3–5 mL/s, resulting in total iodine doses of 35–36 g and iodine delivery rates ranging between 0.9 and 1.75 gI/s [3–6,9,10]. Recent studies by Schoellnast et al. [11,12] have compared a CA with standard iodine concentra- tion (300 mgI/mL) delivered at 1.2 gI/s with a CA containing high iodine concentration (400 mgI/mL) delivered at 1.6 gI/s (equal total iodine dose of 36 g) for MSCT angiography of the pulmonary arteries, and found that pulmonary arterial enhance- ment and visualization of subsegmental pulmonary arteries is improved with higher iodine delivery rate. Similar findings have been reported by Setty et al. [14] for a comparison of CA 0720-048X/$ – see front matter © 2008 Published by Elsevier Ireland Ltd. doi:10.1016/j.ejrad.2008.01.058