Lin Wilson, Jeffrey R Brooke, Trinh Angela, Olcott Eric W
1 Department of Radiology, Stanford University School of Medicine, 300 Pasteur Dr, H1307, Stanford, CA 94305-5105.
2 Department of Radiology (114), Veterans Affairs Palo Alto Health Care System, Palo Alto, CA.
AJR Am J Roentgenol. 2017 Sep;209(3):W128-W138. doi: 10.2214/AJR.17.18059.
The purpose of this study is to identify the anatomic locations of appendixes on CT when graded compression sonography fails to visualize the appendix.
The study included 197 patients with suspected appendicitis whose appendixes were not visualized on graded compression sonography performed with typically used transducers of at least 10 MHz, who underwent CT within 48 hours following graded compression sonography, and who had available either pathologic examination following surgery or 6-week follow-up if surgery was not performed. Appendixes were retrospectively localized using four transverse quadrants (including the posteromedial quadrant) centered on the ileocecal valve and projected vertically, the craniocaudal level relative to the iliac crests, and the depth of the appendix as measured from the surface of the skin. Data were assessed using the Fisher exact test, t test, multinomial test, binomial distribution, ANOVA, and linear regression.
Appendixes were most frequently located in the posteromedial quadrant (123 of 197 patients [62.4%]; 95% CI, 55.3-69.2%) at a statistically significantly greater frequency than that expected by chance (p < 0.00001). Appendixes were located above the iliac crests in 19.8% of patients (39/197; 95% CI, 14.5-26.1%) and at depths exceeding the penetration of typical transducers of at least 10 MHz in 19.3% of patients (38/197; 95% CI, 14.0-25.5%). All appendixes (95% CI, 98.1-100.0%) were located within the range of 6-MHz transducers.
Appendixes that are not visualized on graded compression sonography are most frequently located in the posteromedial quadrant and are often located above the iliac crests or at depths too great for visualization with typically used transducers of at least 10 MHz. Accordingly, when the appendix is not visualized on graded compression sonography, targeted scanning of the posteromedial quadrant and the region above the iliac crests, and scanning with 6-MHz transducers, may enable visualization of the appendix and are recommended additions to scanning protocols.
本研究的目的是确定在分级加压超声未能显示阑尾时，阑尾在CT上的解剖位置。
本研究纳入了197例疑似阑尾炎患者，这些患者使用至少10MHz的常用探头进行分级加压超声检查时未显示阑尾，在分级加压超声检查后48小时内接受了CT检查，并且术后有病理检查结果或（若未进行手术）有6周的随访结果。阑尾通过以回盲瓣为中心的四个横向象限（包括后内侧象限）进行回顾性定位，并垂直投影，确定相对于髂嵴的头尾水平，以及从皮肤表面测量的阑尾深度。使用Fisher精确检验、t检验、多项检验、二项分布、方差分析和线性回归对数据进行评估。
阑尾最常位于后内侧象限（197例患者中的123例[62.4%]；95%CI，55.3 - 69.2%），其出现频率在统计学上显著高于随机预期（p < 0.00001）。19.8%的患者（39/197；95%CI，14.5 - 26.1%）阑尾位于髂嵴上方，19.3%的患者（38/197；95%CI，14.0 - 25.5%）阑尾深度超过至少为10MHz的典型探头的穿透深度。所有阑尾（95%CI，98.1 - 100.0%）均位于6MHz探头的探测范围内。
分级加压超声未显示的阑尾最常位于后内侧象限，且常位于髂嵴上方或深度过大以至于至少10MHz的常用探头无法显示。因此，当分级加压超声未显示阑尾时，对后内侧象限和髂嵴上方区域进行靶向扫描，以及使用6MHz探头进行扫描，可能有助于显示阑尾，建议将其添加到扫描方案中。
