Department of Surgery, Maastricht University Medical Center, Maastricht, The Netherlands; Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands.
Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands.
Eur J Vasc Endovasc Surg. 2014 Dec;48(6):676-84. doi: 10.1016/j.ejvs.2014.04.025. Epub 2014 Jun 14.
A layer of intraluminal thrombus is commonly observed in abdominal aortic aneurysms (AAAs). The purpose of this study was to investigate whether AAAs with high thrombus signal intensity (SI) at T1-weighted (T1w) magnetic resonance imaging (MRI) exhibit a faster aneurysm growth rate.
This was a prospective follow-up study. Patients with a small AAA underwent MRI examinations at 6 month intervals. Aneurysm thrombus and psoas muscle SI at the point of maximal diameter on T1w images were measured and expressed as a ratio (thrombus SI/muscle SI). Based on these measurements, patients were categorized into three groups: AAA with relative thrombus SI above (group A) and below (group B) the mean relative thrombus SI of 1.20. Patients with AAA without thrombus constituted group C. Eight patients were scanned twice within 2 weeks to investigate scan-rescan reproducibility. Aneurysm growth rates were expressed as the change in maximal cross sectional area (cm(2)).
A total of 35 patients (m/f: 26/9; age 72 ± 7 years; AAA maximal diameter 4.9 ± 0.5 cm) were included. Mean aneurysm growth rate for patients in group A (n = 11, 1.87 cm(2)/0.5 year) was two-fold higher than group B (n = 17, 0.78 cm(2)/0.5 year, p = .005) and eight-fold higher than group C (n = 7, 0.23 cm(2)/0.5 years, p = .004) at 6 months' follow-up. At 12 months' follow-up, the mean aneurysm growth rate remained significantly higher in group A (n = 7, 3.03 cm(2)/year) than groups B (n = 10, 1.63 cm(2)/year, p = .03) and C (n = 7, 0.73 cm(2)/year, p = .004). The reproducibility for thrombus SI measurements was found to be high with a coefficient of variation of 6.2%. Aneurysm maximal cross-sectional area at baseline was not significantly different for the three groups.
Abdominal aortic aneurysms with high thrombus SI on T1w MR images are associated with higher aneurysm growth rates.
腹主动脉瘤（AAA）中常可见到管腔内血栓。本研究的目的是探讨 T1 加权（T1w）磁共振成像（MRI）中血栓信号强度（SI）较高的 AAA 是否具有更快的瘤体生长速度。
这是一项前瞻性随访研究。小 AAA 患者每隔 6 个月接受 MRI 检查。在 T1w 图像的最大直径处测量瘤体血栓和腰大肌的 SI，并表示为比值（血栓 SI/肌肉 SI）。根据这些测量结果，患者分为三组：血栓 SI 相对值高于（组 A）和低于（组 B）1.20 的平均相对血栓 SI。无血栓的 AAA 患者为组 C。8 例患者在 2 周内接受了两次扫描，以研究扫描间的可重复性。瘤体生长率用最大横截面积的变化（cm2）表示。
共纳入 35 例患者（男/女：26/9；年龄 72±7 岁；AAA 最大直径 4.9±0.5cm）。组 A（n=11）的平均瘤体生长率为 1.87cm2/0.5 年，高于组 B（n=17，0.78cm2/0.5 年，p=0.005）和组 C（n=7，0.23cm2/0.5 年，p=0.004），随访 6 个月时差异有统计学意义。随访 12 个月时，组 A（n=7，3.03cm2/年）的平均瘤体生长率仍显著高于组 B（n=10，1.63cm2/年，p=0.03）和组 C（n=7，0.73cm2/年，p=0.004）。血栓 SI 测量的重复性较好，变异系数为 6.2%。三组患者的基线 AAA 最大横截面积无显著差异。
T1w MRI 上血栓 SI 较高的腹主动脉瘤与更高的瘤体生长速度相关。
