PULMONARY MR-ANGIOGRAPHY AT 1.0 T - EARLY RESULTS WITH K-SPACE SEGMENTED AND POST-CONTRAST TURBOFLASH 2-DIMENSIONAL TIME-OF-FLIGHT SEQUENCES

Purpose: To evaluate the combined performance of two time-of-flight me thods in imaging the pulmonary arteries. Materials and methods: This s tudy was prospectively conducted in 28 patients suspected for pulmonar y embolism (PE). Sixteen patients were free of pulmonary vascular dise ase, and 12 had pulmonary vascular disease as demonstrated by pulmonar y angiography. To reduce artifacts caused by cardiac and respiratory m otion, MR images were acquired in all subjects using bi-dimensional (2 D), gradient-recalled echo (GRE), breath-hold techniques. Sagittal thi n (6-mm) sections obtained with ECG gating, k-space segmentation and i ncremented flip-angles (TONE), and coronal thick (15-mm) sections obta ined after a unique injection of Gadolinium chelate were used. Results : High quality images were obtained in all 16 (100%) subjects free of pulmonary disease with both techniques, and in 10 and 12 (87% and 100% ) patients suspected for pulmonary artery disease with sagittal and co ronal Gd-enhanced MRA, respectively, In patients free of pulmonary dis ease, TONE images exhibited distal pulmonary arteries with 2.1 subsegm ental divisions on average, whereas Gd-enhanced TurboFLASH images were the most accurate to identify proximal pulmonary arteries within the mediastinum, even if only 0.8 subsegmental divisions were seen on aver age. A correct diagnosis of pulmonary embolism was obtained in all cas es but one, with use of both MRA techniques, with an overall accuracy of 86%. Conclusion: The association of segmented sagittal GRE images a nd coronal first-pass Gd-enhanced GRE images can provide information u pon normal and diseased pulmonary arteries within the mediastinum unti l subsegmental pulmonary branches, even in patients with short-breathi ng. Further studies of patients with various pulmonary artery diseases will confirm whether this technique makes pulmonary MRA feasible in c linical routine situations.