MR angiography of internal carotid arteries: Breath-hold Gd-enhanced 3D fast imaging with steady-state precession versus unenhanced 2D and 3D time-of-flight techniques

Purpose: The purpose of this work was to compare Gd-enhanced breath-hold fa st imaging with steady-state precession (Gd-FISP) with unenhanced time-of-f light (TOF) sequences in evaluating internal carotid arteries (ICAs). Method: Thirty patients underwent three unenhanced TOF sequences [2D travel ing saturation (Travelsat); 3D tilted optimized nonsaturated excitation (TO NE); TOF 3D Multislab] and two breath-hold 3D Gd-FISP sequences with automa ted intravenous contrast agent injection (axial and coronal). ICAs were cla ssified as normal (no stenosis); with mild (<30%), moderate (30-70%), or se vere stenosis; or occluded (100%). Digital subtraction angiography (DSA) wi th aortic arch injection was used as a reference technique. Results: DSA revealed 20 normal ICAs; 11 mild, 9 moderate, and 14 severe st enoses; and 2 occlusions. DSA and all MR angiography (MRA) sequences diagno sed the occlusion of four common carotid arteries. The TOF 2D overestimated 10 stenoses, TOF 3D TONE 9, and TOF 3D Multislab 5; Gd-FISP 3D overestimat ed only 2 of them, reaching the highest sensitivity and specificity for sev ere stenoses. Significant differences were found between the overestimation of Gd-FISP and each of the three unenhanced sequences (0.0020 < p < 0.0313 , Wilcoxon and McNemar tests). Severe artifacts were observed with TOF tech niques only. Conclusion: Gd-FISP is an interesting, largely artifact-free improvement fo r MRA of ICAs.