Kontrastmittelfreie 1,5 T-Magnetresonanzangiographie in der Lungenarterienembolie-Diagnostik: Klinische Evaluation der radialen quiescent-interval slice-selective (QISS)-MRA im Vergleich zur kartesischen balanced steady-state free precession-MRA und zur kontrastmittelverstärkten Computertomographie

Free-breathing noncontrast-enhanced (non-CE) magnetic resonance angiography (MRA) techniques are of considerable interest for the diagnosis of acute pulmonary embolism (APE), due to the possibility for repeated examinations, avoidance of side effects from iodine-based contrast agents, and the absence of ionizing radiation exposure as compared to CE-computed tomographic angiography (CTA). To analyze the clinical performance of free-breathing and electrocardiogram (ECG)-gated radial quiescent-interval slice-selective (QISS)-MRA compared to CE-CTA and to Cartesian balanced steady-state free precession (bSSFP)-MRA. Assessment: Thirty patients with confirmed APE and 30 healthy volunteers. SNR and CNR were computed to compare the pulmonary imaging quality between MRA methods. The pulmonary arterial tree was divided into 25 branches and an ordinal scoring system was used to assess the image quality of each pulmonary branch. The clinical performance of the two MRA techniques in accurately assessing APE was evaluated with respect to CE-CTA as the clinical reference standard. Results: Thrombus-mimicking artifacts appeared more frequently in lobar and peripheral arteries of patients with Cartesian bSSFP than with radial QISS-MRA. The relative increases in SNR and of CNR provided by radial QISS-MRA with respect to Cartesian bSSFP-MRA were 30–35%. The image quality of pulmonary arterial branches was considered good to excellent in 77.2% of patients with radial QISS-MRA and in 43.2% with Cartesian bSSFP-MRA. The clinical performance of radial QISS-MRA was higher than Cartesian bSSFP-MRA for grading embolism, with a total sensitivity of 86.0% vs. 80.6% and a specificity of 93.3% vs. 84.0%, respectively. Radial QISS-MRA is a reliable and safe non-CE angiographic technique with promising clinical potential compared to Cartesian bSSFP-MRA and as an alternative technique to CE-CTA for the diagnosis of APE