- 期刊
降低經導管微創主動脈瓣植入術的術前電腦斷層檢查對比劑使用劑量之成效評估
To Evaluate Image Quality Using Reduced Contrast Media (CM) Volume in Pre-TAVI CT Assessment
摘要
在2002年發表的「經導管主動脈瓣膜植入術」(transcatheter aortic valve implantation, TAVI)使用生物合成瓣膜，較少侵入性不需鋸開胸骨而且較少的恢復期與減少病患住院天數，為主動脈狹窄病人的治療帶來新希望。經導管主動脈瓣膜植入術電腦斷層檢查評估過去常需要高達120 ml以上的對比劑（contrast media, CM），以利充盈整個大動脈與周 邊相關的血管。然而，術前電腦斷層所需的對比劑可能會影響TAVI患者原本就不佳的腎功能而增加其腎功能對比劑引發腎病變之（contrast-induced nephropathy, CIN）風險。本研究的主要目的在於降低電腦斷層中對比劑的使用量，並評估此一方式對影像品質的影響。材料與方法:收集12位TAVI術前病患的影像資料，所使用的電腦斷層攝影機為第二代雙源CT掃描儀(Definition Flash; Siemens Healthcare, Forchheim, Germany)。每位病患皆接受心電圖後門控技術螺旋式CT血管攝影掃描心臟，並使用高螺距掃描(FLASH模式)從頸總動脈(c3)到大腿動脈的近端進行掃描。所有病患皆接受對比劑(Ultravist® (iopromide)) (370 mg Iodine per ml)，以兩段式注射模式進行對比劑注射，其注射體積及速率分別為注射模式：體積= 50ml; 流速= 5ml / s 及體積= 35ml;流速= 3.5ml / s，最後用生理 鹽水沖洗100ml，流速= 4ml / s，研究結果：主動脈根部的平均衰減值和CNR（HU±SD） 分別為(447.75±6.1 HU)和(10±4.2)。平均有效輻射劑量在心電圖後門控技術螺旋式CT血管攝影在心臟為13.79±7.34 mSv；高螺距掃描從頸總動脈(c3)到大腿動脈的近端為 4.25±1.81 mSv。結論：使用Flash模式可以顯著減少對比劑體積，也可降低有效輻射劑量，同時保持足夠的圖像品質，以評估主動脈根部和週邊血管導管置入部位。
並列摘要
In 2002, a new technique was developed that made it possible to implant another type of bioprosthesis using catheterization (transcatheter aortic valve implantation [TAVI]). This procedure is less invasive because it facilitates access to the heart without requiring surgical opening of the sternum and furthermore, causes shorter recovery times and hospital stay. The patients may be benefit from the new treatment. TAVI protocols - as described in the literature - usually entail the injection of large contrast media (CM) volumes up to 120 ml to ensure optimal filling of the aortic root as well as the peripheral arteries. However, the required CM may pose a risk for TAVI candidates who are frequently suffering from impaired renal function and considered to be at increased risk of contrast-induced nephropathy (CIN).Purpose: To evaluate image quality by using reduced CM volume in pre-TAVI CT. Methods: To collect the image data of the twelve patients s referred for pre-TAVI examination were evaluated with using the 2nd generation dual source CT scanner (Definition Flash; Siemens Healthcare, Forchheim, Germany). Patients received a combined scanning protocol: retrospective electrocardiography (ECG)-gated helical CTA of the heart immediately followed by a high-pitch spiral (FLASH mode) CTA from common carotid arteries (C3) to femoral arteries. Contrast infusion protocol was separated by two steps as follows: The first step: CM(Ultravist® (iopromide)) (370 mg Iodine per ml ): volume=50 ml, flow rate=5 ml/s for CTA of heart; The second step: CM(Ultravist® (iopromide)) (370 mg Iodine per ml ): volume=35 ml, flow rate=3.5 ml/s for the CTA of aorta and major branches followed by a saline flush of 100 ml with flow rate=4ml/s. Results: As a result of the evaluation from the 12 patients regarding the diagnostic image quality for TAVI measurements, as following: The mean attenuation values of the aortic roots and CNR (HU ± SD) (9) were: (447.75 ± 6.1 HU) and (10 ± 4.2), respectively. The mean effective dose after electrocardiographic gating technique spiral CT angiography was 13.79 ± 7.34 mSv in the heart; the high pitch scan from the common carotid artery (c3) to the proximal end of the thigh artery was 4.25 ± 1.81 mSv. Conclusion: Using the Flash mode can significantly reduce the CM volume and the effective radiation dose while maintaining adequate image quality to assess the aortic root and peripheral vascular catheter placement.