All Title Author
Keywords Abstract

PLOS ONE  2014 

Quantitative Measurement of Elasticity of the Appendix Using Shear Wave Elastography in Patients with Suspected Acute Appendicitis

DOI: 10.1371/journal.pone.0101292

Full-Text   Cite this paper   Add to My Lib

Abstract:

Introduction Shear wave elastography (SWE) has not been studied for diagnosing appendicitis. We postulated that an inflamed appendix would become stiffer than a normal appendix. We evaluated the elastic modulus values (EMV) by SWE in healthy volunteers, patients without appendicitis, and patients with appendicitis. We also evaluated diagnostic ability of SWE for differentiating an inflamed from a normal appendix in patients with suspected appendicitis. Materials and Methods Forty-one patients with clinically suspected acute appendicitis and 11 healthy volunteers were prospectively enrolled. Gray-scale ultrasonography (US), SWE and multi-slice computed tomography (CT) were performed. The EMV was measured in the anterior, medial, and posterior appendiceal wall using SWE, and the highest value (kPa) was recorded. Results Patients were classified into appendicitis (n = 30) and no appendicitis groups (n = 11). One case of a negative appendectomy was detected. The median EMV was significantly higher in the appendicitis group (25.0 kPa) compared to that in the no appendicitis group (10.4 kPa) or in the healthy controls (8.3 kPa) (p<0.001). Among SWE and other US and CT features, CT was superior to any conventional gray-scale US feature or SWE. Either the CT diameter criterion or combined three CT features predicted true positive in 30 and true negative in 11 cases and yielded 100% sensitivity and 100% specificity. An EMV of 12.5 kPa for the stiffest region of the appendix predicted true positive in 28, true negative in 11, and false negative in two cases. The EMV (≥12.5 kPa) yielded 93% sensitivity and 100% specificity. Conclusion Our results suggest that EMV by SWE helps distinguish an inflamed from a normal appendix. Given that SWE has high specificity, quantitative measurement of the elasticity of the appendix may provide complementary information, in addition to morphologic features on gray-scale US, in the diagnosis of appendicitis.

References

[1]  Balthazar EJ, Rofsky NM, Zucker R (1998) Appendicitis: the impact of computed tomography imaging on negative appendectomy and perforation rates. Am J Gastroenterol 93: 768–771. doi: 10.1111/j.1572-0241.1998.222_a.x
[2]  Rao PM, Rhea JT, Rattner DW, Venus LG, Novelline RA (1999) Introduction of appendiceal CT: impact on negative appendectomy and appendiceal perforation rates. Ann Surg 229: 344–349. doi: 10.1097/00000658-199903000-00007
[3]  Brandt MM, Wahl WL (2003) Liberal use of CT scanning helps to diagnose appendicitis in adults. Am Surg 69: 727–731 discussion 731–722.
[4]  Rettenbacher T, Hollerweger A, Macheiner P, Rettenbacher L, Frass R, et al. (2000) Presence or absence of gas in the appendix: additional criteria to rule out or confirm acute appendicitis–evaluation with US. Radiology 214: 183–187. doi: 10.1148/radiology.214.1.r00ja20183
[5]  van Randen A, Bipat S, Zwinderman AH, Ubbink DT, Stoker J, et al. (2008) Acute appendicitis: meta-analysis of diagnostic performance of CT and graded compression US related to prevalence of disease. Radiology 249: 97–106. doi: 10.1148/radiol.2483071652
[6]  Orth RC, Guillerman RP, Zhang W, Masand P, Bisset GS III (2014) Prospective Comparison of MR Imaging and US for the Diagnosis of Pediatric Appendicitis. Radiology: 132206.
[7]  Aspelund G, Fingeret A, Gross E, Kessler D, Keung C, et al. (2014) Ultrasonography/MRI Versus CT for Diagnosing Appendicitis. Pediatrics 133: 586–593. doi: 10.1542/peds.2013-2128
[8]  Leeuwenburgh MM, Wiarda BM, Wiezer MJ, Vrouenraets BC, Gratama JW, et al. (2013) Comparison of imaging strategies with conditional contrast-enhanced CT and unenhanced MR imaging in patients suspected of having appendicitis: a multicenter diagnostic performance study. Radiology 268: 135–143. doi: 10.1148/radiol.13121753
[9]  Tanter M, Bercoff J, Athanasiou A, Deffieux T, Gennisson JL, et al. (2008) Quantitative assessment of breast lesion viscoelasticity: initial clinical results using supersonic shear imaging. Ultrasound Med Biol 34: 1373–1386. doi: 10.1016/j.ultrasmedbio.2008.02.002
[10]  Carneiro-Pla D (2013) Ultrasound elastography in the evaluation of thyroid nodules for thyroid cancer. Curr Opin Oncol 25: 1–5. doi: 10.1097/cco.0b013e32835a87c8
[11]  Itoh A, Ueno E, Tohno E, Kamma H, Takahashi H, et al. (2006) Breast disease: clinical application of US elastography for diagnosis. Radiology 239: 341–350. doi: 10.1148/radiol.2391041676
[12]  Asteria C, Giovanardi A, Pizzocaro A, Cozzaglio L, Morabito A, et al. (2008) US-elastography in the differential diagnosis of benign and malignant thyroid nodules. Thyroid 18: 523–531. doi: 10.1089/thy.2007.0323
[13]  Nightingale K (2011) Acoustic Radiation Force Impulse (ARFI) Imaging: a Review. Curr Med Imaging Rev 7: 328–339. doi: 10.2174/157340511798038657
[14]  Szczepanek-Parulska E, Wolinski K, Stangierski A, Gurgul E, Biczysko M, et al. (2013) Comparison of diagnostic value of conventional ultrasonography and shear wave elastography in the prediction of thyroid lesions malignancy. PLoS One 8: e81532. doi: 10.1371/journal.pone.0081532
[15]  Kalan M, Talbot D, Cunliffe WJ, Rich AJ (1994) Evaluation of the modified Alvarado score in the diagnosis of acute appendicitis: a prospective study. Ann R Coll Surg Engl 76: 418–419.
[16]  Cha SW, Jeong WK, Kim Y, Kim MY, Kim J, et al. (2014) Nondiseased liver stiffness measured by shear wave elastography: a pilot study. J Ultrasound Med 33: 53–60. doi: 10.7863/ultra.33.1.53
[17]  Machin D, Campbell M, Fayers P, Pinol A (1997) Sample Size Tables for Clinical Studies. Malden, MA: Blackwell Science.
[18]  Zar JH (1984) Biostatistical Analysis. Englewood Cliffs, New Jersey: Prentice-Hall.
[19]  Sarvazyan AP, Rudenko OV, Swanson SD, Fowlkes JB, Emelianov SY (1998) Shear wave elasticity imaging: a new ultrasonic technology of medical diagnostics. Ultrasound Med Biol 24: 1419–1435. doi: 10.1016/s0301-5629(98)00110-0
[20]  Flum DR, Morris A, Koepsell T, Dellinger EP (2001) Has misdiagnosis of appendicitis decreased over time? A population-based analysis. Jama 286: 1748–1753. doi: 10.1001/jama.286.14.1748
[21]  Goldin AB, Khanna P, Thapa M, McBroom JA, Garrison MM, et al. (2011) Revised ultrasound criteria for appendicitis in children improve diagnostic accuracy. Pediatr Radiol 41: 993–999. doi: 10.1007/s00247-011-2018-2
[22]  Yoon JH, Jung HK, Lee JT, Ko KH (2013) Shear-wave elastography in the diagnosis of solid breast masses: what leads to false-negative or false-positive results? Eur Radiol 23: 2432–2440. doi: 10.1007/s00330-013-2854-6

Full-Text

comments powered by Disqus

Contact Us

service@oalib.com

QQ:3279437679

微信:OALib Journal