Siegel C L, Cohan R H, Korobkin M, Alpern M B, Courneya D L, Leder R A
Department of Radiology, University of Michigan Medical Center, Ann Arbor 48109-0030.
AJR Am J Roentgenol. 1994 Nov;163(5):1123-9. doi: 10.2214/ajr.163.5.7976888.
We evaluated a variety of internal architectural features in ruptured and nonruptured abdominal aortic aneurysms to determine whether any features are associated more frequently with ruptured abdominal aortic aneurysms. These features may be useful in identifying subtle ruptures when no obvious retroperitoneal hematoma is present and may be helpful in predicting unstable aneurysms at risk for rupture.
The CT scans of 52 patients with ruptured abdominal aortic aneurysms were reviewed and compared with those of 56 patients with asymptomatic nonruptured aneurysms exceeding 4.5 cm in diameter. All aneurysms were evaluated for size, rim calcification, thrombus amount, thrombus calcification, and lumen irregularity. In addition, four different thrombus patterns were identified and evaluated, including homogeneous, diffusely heterogeneous, periluminal halo, and crescent patterns. Statistical comparisons were adjusted for differences in size between the two groups.
Age, gender, and aneurysm length were not statistically different between the two groups. A larger diameter was found in the ruptured aneurysm group: 7.4 (anteroposterior) x 7.9 (transverse) cm versus 5.9 x 6.1 cm (p = .00001). More thrombus surrounded the nonruptured aneurysms (p = .014). Thrombus calcification was seen in 25% (14/56) of the control group and in 13% (7/52) of the rupture group (p = .01). Two thrombus patterns, homogeneous and periluminal halo, were encountered with similar frequencies in both groups. The diffusely heterogeneous pattern was seen more in the control group. A crescent of increased attenuation was encountered only in patients with ruptured aneurysms, at an incidence of 21% (11/52) (p = .0005). Thick and thin wall calcifications were seen in both groups, but a focal discontinuity in circumferential calcification was seen only in association with ruptured aneurysms, at an incidence of 8% (4/52) (p = .008). There was no significant difference in the number of patients whose patent lumen was irregular.
In our series, detection of a high-attenuation crescent or focal gap of otherwise circumferential wall calcification is associated with aneurysm rupture. The homogeneous, diffusely heterogeneous, and periluminal halo patterns are not specifically associated with aortic rupture. There were no significant differences in the amount of wall calcification or frequency of lumenal irregularity between patients with ruptured and those with nonruptured aneurysms.
我们评估了破裂和未破裂腹主动脉瘤的多种内部结构特征，以确定是否有任何特征更频繁地与破裂的腹主动脉瘤相关。当没有明显的腹膜后血肿时，这些特征可能有助于识别细微的破裂，并且可能有助于预测有破裂风险的不稳定动脉瘤。
回顾了52例破裂腹主动脉瘤患者的CT扫描结果，并与56例直径超过4.5 cm的无症状未破裂动脉瘤患者的CT扫描结果进行比较。对所有动脉瘤的大小、边缘钙化、血栓量、血栓钙化和管腔不规则性进行评估。此外，识别并评估了四种不同的血栓模式，包括均匀型、弥漫不均质型、管腔周围晕型和新月型。对两组之间大小差异进行了统计学调整比较。
两组之间的年龄、性别和动脉瘤长度无统计学差异。破裂动脉瘤组的直径更大：7.4（前后径）×7.9（横径）cm，而未破裂组为5.9×6.1 cm（p = .00001）。未破裂动脉瘤周围的血栓更多（p = .014）。对照组25%（14/56）的患者有血栓钙化，破裂组为13%（7/52）（p = .01）。均匀型和管腔周围晕型这两种血栓模式在两组中出现的频率相似。弥漫不均质型在对照组中更常见。仅在破裂动脉瘤患者中发现了衰减增加的新月形，发生率为21%（11/52）（p = .0005）。两组均可见厚壁和薄壁钙化，但仅在破裂动脉瘤中发现环形钙化的局灶性中断，发生率为8%（4/52）（p = .008）。有管腔不规则的患者数量无显著差异。
在我们的系列研究中，检测到高衰减新月形或环形壁钙化的局灶性间隙与动脉瘤破裂相关。均匀型、弥漫不均质型和管腔周围晕型与主动脉破裂无特异性关联。破裂和未破裂动脉瘤患者之间的壁钙化量或管腔不规则频率无显著差异。
