Assessment of Contrast-enhanced 3D Ultrafast Pulmonary MR Angiography Using Test Injection: Comparison betweenSingle Dose and Double Dose

ABSTRACT

PURPOSE: Contrast-enhanced 3-D ultrafast MR angiography is a widely accepted MR imaging technique for theevaluation of the carotid artery, aorta, renal artery, mesenteric artery and portal venous system. To esti-mateitsclinical usefulness, single -and double- dose contrast-enhanced 3-D ultrafast pulmonary MR angiography wasassessed after a timing examination was performed. MATERIALS AND METHODS: Twenty volunteers underwentgadolinium-enhanced ultrafast pulmonary MR angiog-raphy( 3-D FISP, TR[msec]/TE[msec]=5.0/2.0, with 25 degrees flipangle). In ten volunteers(single-dose injection group) pulmonary MR angiography was performed after theadminstration of 0.1 mmol/kg(single dose injec-tion group), while the other ten(double-dose injection group) eachreceived, prior to angiography, 0.2 m m o l / kg. In all cases, a timing examination was performed during axialturbo-FLASH imaging(TR/TE/TI=8.5/4.0/100, 1 0 degree flip angle) after injection of the same dose as that used forsubsequent contrast-enhanced pulmonary MR angiography. In both groups, overall image quality, pulmonary arteryvisibility and contrast-to-noise ratio of the pulmonary artery were assessed on the basis of images obtained.RESULTS: With regard to overall image quality, there was no significant statistical difference between the twogroups (P>0.05), and in both, depiction of the central and lobar pulmonary artery was excellent. As regardsdepiction of the segmental artery, the average grading of the single dose injection group was 2.83 +/- 0.32, that ofthe double dose injection group was 2.85 +/-0.3, with no statistical significance(P>0.05). With respect tocon-trast-to-noise ratio of the central, lobar, and segmental arteries, the best results were obtained by thedouble dose injection group(P<0.05). CONCLUSION: Although the contrast-to-noise ratio in the double-dose injectiongroup was better than that in the single-dose group, differences in overall image quality and pulmoanry arterydepiction were not statistically significant. Thus, single-dose, contrast-enhanced 3-D ultrafast pulmonary MRangiography can provide useful images in clinical trials.