Department of Clinical Radiology, University Hospitals Grosshadern, Ludwig-Maximilians University, Grosshadern Campus, Marchioninistr 15, 81377 Munich, Germany.
J Vasc Interv Radiol. 2010 Mar;21(3):315-21. doi: 10.1016/j.jvir.2009.10.040. Epub 2010 Jan 22.
To compare true and "virtual" noncontrast images derived from dual-energy CT examinations in patients after endovascular repair of aortic aneurysms.
Seventy dual-energy CT examinations were performed on a dual-source CT scanner with a single-energy noncontrast scan and a dual-energy acquisition in venous phase. True and virtual noncontrast images were compared regarding image quality, calcifications in true noncontrast images, subtraction of calcification in virtual noncontrast images, and acceptance levels by two radiologists. Presence of endoleaks was assessed on venous-phase images and on virtual or true noncontrast images. In addition, the acceptance of color-coded images, in which iodine information is colored, was assessed. Possible dose reduction of a single-phase dual-energy examination protocol was compared with a standard biphasic examination protocol.
Twenty-four endoleaks were detected and correctly classified with both approaches. Mean image quality was rated good for virtual noncontrast images (1.97 +/- 0.99) and excellent for true noncontrast images (1.16 +/- 0.37; P< .0001). Ninety-four percent of virtual noncontrast images were rated as diagnostic, and 80% of all true noncontrast images showed calcifications within the aneurysm. Subtraction of calcification in virtual noncontrast images was classified as none (30%), minimal (40%), moderate (24%), or severe (6%). Eighty-three percent of color-coded images were rated as fully diagnostic, 11% were accepted with restrictions, and 6% were nondiagnostic. Possible dose reduction of a single-phase dual-energy protocol, compared with a standard biphasic protocol, was 44%.
Dual-energy CT makes a reliable detection of endoleaks feasible in a single acquisition. This provides a potential dose reduction for patients who have to undergo lifelong follow-up examinations after endovascular aneurysm repair.
比较血管内修复主动脉瘤后患者的双能 CT 检查的真实和“虚拟”非增强图像。
在双源 CT 扫描仪上进行了 70 次双能 CT 检查，采用单次能非增强扫描和静脉期双能采集。两名放射科医生比较了真实非增强图像的图像质量、真实非增强图像中的钙化、虚拟非增强图像中的钙化减影以及接受程度。评估静脉期图像以及虚拟或真实非增强图像上的内漏。此外，还评估了碘信息彩色编码的彩色编码图像的接受程度。比较了单期双能检查方案和标准双期检查方案的可能剂量减少。
两种方法均正确检测到 24 例内漏并进行分类。虚拟非增强图像的平均图像质量评分为良好（1.97±0.99），真实非增强图像评分为优秀（1.16±0.37；P<0.0001）。94%的虚拟非增强图像被评为诊断性，80%的所有真实非增强图像显示动脉瘤内有钙化。虚拟非增强图像中的钙化减影分为无（30%）、轻微（40%）、中度（24%）或严重（6%）。83%的彩色编码图像被评为完全诊断性，11%有条件接受，6%不可诊断。与标准双期方案相比，单期双能方案的可能剂量减少了 44%。
双能 CT 可在单次采集时可靠地检测到内漏。这为血管内修复主动脉瘤后需要进行终身随访检查的患者提供了潜在的剂量减少。
