EXPERIMENTAL EVALUATION OF CONTRAST-ENHAN CED HIGH-RESOLUTION MR-ANGIOGRAPHY IN THE RABBIT GD-DTPA VERSUS GD-DTPA POLYLYSINE

Purpose: To evaluate the qualitative and quantitative efficacy of Gd-D TPA and Gd-DTPA polylysine for contrast-enhanced high resolution MRA ( CMRA) of the abdominal vessels. Materials and methods: In ten anesthes ized rabbits (average weight 4.3 kg) MR angiography was performed usin g a 1.5 T MR unit (Magnetom SP 63; Siemens Erlangen) and a CP head coi l. Arterial MRA (FISP 3D TONE, TR/TE=33/8, Flip 20 degrees) and venous MRA (FLASH 2D, TRITE = 37/10, Flip 60 degrees) was performed before a nd after administration of the paramagnetic contrast agents (n=5) or G d-DTPA (n = 5) at a dosage of 0.1 mmol/kg. In all studies the single s ections and the MIP reconstructions were evaluated quantitatively by m easuring and calculating signal intensity, percentage enhancement, sig nal-to-noise and contrast-to-noise ratios. All studies were assessed q ualitatively for visualization and distinction of the arterial and ven ous vessel system by three independent observers before and after the administration of contrast agent. Results: Gd-DTPA-enhanced arterial F ISP 3D tone led to a percentage enhancement of 30% for the kidneys, 12 % for the superior mesenteric artery, 18% for the deep circumfluent il iac artery, and 7% for the internal iliac artery. In FLASH 2D sequence s Gd-DTPA led to a good CIN only for venous abdominal vessels like the left renal vein (2.59) and internal iliac vein (1.66); the percentage enhancement of these structures was between 16 and 21%. Qualitative c omparison also showed no significant improvement after injection of Gd -DTPA. Tn FISP 3D TONE sequences Gd-DTPA polylysine led to a strong pe rcentage enhancement of right and left kidney (21 and 40%) and deep ci rcumfluent iliac artery (17%). Qualitative evaluation showed improved delineation and contrast of low-diameter vessels, while the soft tissu e was only slightly enhanced and did not impair vessel visualization. Conclusion: CMRA using Gd-DTPA and Gd-DTPA polylysine significantly im proved the delineation of abdominal vessels, with Gd-DTPA polylysine b eing supprior.