Contrast-Enhanced Carotid Magnetic Resonance Angioraphy: Comparison of Single-Dose and Double-Dose of Gadolinium Using the Randomly Segmented Central k-Space Ordering Technique

　　　　　背景：本研究目的主要在評估使用中央k空間分隔隨機排序技術在頸部動脈磁振血管造影時，單倍劑量的造影劑是否足夠，進而取代傳統使用的雙倍劑量。 方法：我們針對44名病患(平均年齡61.3±9.1歲)，隨機分為二組，分別使用單一劑量和雙倍劑量來進行頸部動脈磁振血管造影，使用的影像重組方式為新發展出的中央k空間分隔隨機排序技術。在所有得到的影像我們均取七個特定的部位，測量比較其訊噪比。並且由兩位作者在不知道其影像所使用的劑量之下針對九個區段的動脈呈現的品質以及靜脈回流的程度各別以1到5分作評分。 結果：針對七個特定的部位中，測得的訊噪比只有在頭臂動脈是雙倍劑量較高，而兩組影像在其餘六個部位的比較上均沒有統計上明顯的差異。而在九段血管的表現以及靜脈回流的程度的比較上，兩組亦沒有統計上的差異(p>0.05)。 結論：使用中央k空間分隔隨機排序技術應在頸部動脈磁振血管造影時，可將造影劑劑量減少成單倍劑量。而仍然能夠保有和傳統使用雙倍劑量時一樣的影像品質。
　　　　　Background: The aim of this study was to evaluate whether the single dose of gadolinium is sufficient for contrast-enhanced magnetic resonance angiography (MRA) of carotid arteries with the use of newly developed randomly segmented central k-space ordering technique called contrast-enhanced timing-robust angiography (CENTRA). Methods: A total of 44patients underwent carotid MRA in a 1.5T MR scanner using a fluoroscopically monitored, manually triggered, CENTRA pulse sequence. Patients were randomly assigned into groups according to the dose of contrast medium (gadolinium chelate) administered: group 1 referred to those who received double doses (0.2 mmol/kg) and group 2 received single doses (0.1 mmol/kg). The contrast-to-noise (CNR) ratios of the seven regions of interest were calculated. The delineation of nine vascular regions and the degree of venous overlay wee evaluated by two blinded readers on a five point scale. Results: For quantitative evaluation, the CNRs at the brachiocephalic artery were greater in patients in group 1 than that in group (p=0.015), while the differences did not differ between the two groups for the remaining regions of interest (p>0.05). for qualitative evaluation, there were no significant differences between the two groups in delineation of nine vascular regions and venous overlaying (p>0.05). Conclusion: With the use of the CENTRA technique, carotid MRA may be performed using a single dose of gadolinium and the image quality is comparable to that of the standard double dose proteocol.