Reproducibility of two different methods for performing mean gray value evaluation of cyst content in endometriomas using VOCAL

Objective To compare two different methods (manual sampling of the entire cyst and semi-automated spherical sampling from the central part of the cyst) for calculating the mean gray value (MGV) from the cystic content in endometriomas using virtual organ computer-aided analysis (VOCAL).

Forty-one volumes from histologically confirmed endometriomas were retrieved from our database and the volumes were analyzed to compare the MGVs obtained via the two modalities. In addition, to evaluate the reproducibility in a sample of 20 volumes, two different observers calculated the MGV from cyst content using VOCAL software. For each method, each examiner analyzed the volumes twice, 3 weeks apart, for assessment of intra-observer agreement. First, manual sampling of the internal contour of all the cysts was performed, and 1 week later semi-automated 2-cm sphere sampling from the central part of the cyst was carried out. In addition, the observers recorded the time spent performing each analysis. Inter- and intra-observer reproducibility was evaluated for each method using intra-class correlation coefficients (ICC).

There was no difference in the mean MGV between manual sampling (22.211 ± 7.541) and the semi-automated modality of sampling (23.840 ± 8.621, p = 0.439). The correlation between manual and semi-automated sampling measurement was high (r = 0.92). According to the ICCs, there was no significant difference in interobserver reliability between manual sampling (0.931; 95 % CI, 0.824–0.973) and the semi-automated modality of sampling (0.924; 95 % CI, 0.809–0.970). Intra-observer reproducibility for both examiners was good (ICC > 0.94). Semi-automated measurements were obtained faster than those obtained by manual evaluation (p = 0.0001 for observer 1 and p = 0.083 for observer 2).

Both methods seem to be reliable, but the semi-automated method using the sphere should be preferred because it is a less time-consuming procedure. Similar content being viewed by others

Farquhar C. Endometriosis. BMJ. 2007;334:249–53. Mais V, Guerriero S, Ajossa S, et al. The efficiency of transvaginal ultrasonography in the diagnosis of endometrioma. Fertil Steril. 1993;60:776–80. Moore J, Copley S, Morris J, et al. Systematic review of the accuracy of ultrasound in the diagnosis of endometriosis. Ultrasound Obstet Gynecol. 2002;20:630–4. Raine-Fenning N, Jayaprakasan K, Deb S. Three-dimensional ultrasonographic characteristics of endometriomata. Ultrasound Obstet Gynecol. 2008;31:718–24. Alcázar JL. Three-dimensional ultrasound in gynecology: current status and future perspectives. Curr Womens Health Rev. 2005;1:1–14. Alcázar JL, León M, Galván R, et al. Assessment of cyst content using mean gray value for discriminating endometrioma from other unilocular cysts in premenopausal women. Ultrasound Obstet Gynecol. 2010;35:228–32. Alcázar JL, Prka M. Evaluation of two different methods for vascular sampling by three-dimensional power Doppler angiography in solid and cystic-solid adnexal masses. Ultrasound Obstet Gynecol. 2009;33:349–54. Kudla MJ, Alcázar JL. Does sphere volume affect the performance of three-dimensional power Doppler virtual vascular sampling for predicting malignancy in vascularized solid or cystic-solid adnexal masses? Ultrasound Obstet Gynecol. 2010;35:602–8. Giudice LC. Clinical practice. Endometriosis. N Engl J Med. 2010;362:2389–98. Valentin L. Characterising acute gynaecological pathology with ultrasound: an overview and case examples. Best Pract Res Clin Obstet Gynaecol. 2009;23:577–93. Kudla MJ, Alcázar JL. Spatiotemporal image correlation with spherical sampling and high-definition flow: new 4-dimensional method for assessment of tissue vascularization changes during the cardiac cycle: reproducibility analysis. J Ultrasound Med. 2012;31:73–80. Asch E, Levine D. Variations in appearance of endometriomas. J Ultrasound Med. 2007;26:993–1002. Tekesin I, Anderer G, Hellmeyer L, et al. Assessment of fetal lung development by quantitative ultrasonic tissue characterization: a methodical study. Prenat Diagn. 2004;24:671–6. Heliopoulos J, Vadikolias K, Mitsias P, et al. A three-dimensional ultrasonographic quantitative analysis of non-ulcerated carotid plaque morphology in symptomatic and asymptomatic carotid stenosis. Atherosclerosis. 2008;198:129–35. Saba L, Argiolas GM, Siotto P, et al. Carotid artery plaque characterization using CT multienergy imaging. AJNR Am J Neuroradiol. 2013;34:855–9. Saba L, Piga M, Raz E, et al. Carotid artery plaque classification: does contrast enhancement play a significant role? AJNR Am J Neuroradiol. 2012;33:1814–7. Boris P, Bundgaard F, Olsen A. The CT (Hounsfield unit) number of brain tissue in healthy infants. A new reliable method for detection of possible degenerative disease. Childs Nerv Syst. 1987;3:175–7. Saba L, Guerriero S, Sulcis R, et al. Mature and immature ovarian teratomas: CT, US and MR imaging characteristics. Eur J Radiol. 2009;72:454–63. Guerriero S, Pilloni M, Alcazar JL, et al. Tissue characterization using mean gray value analysis in deep infiltrating endometriosis. Ultrasound Obstet Gynecol. 2013;41:459–64. Huang CY, Wang HI, Wang PH, et al. Mean grey value is lower in endometriomas: differentiating a hypoechogenic adnexal cyst by 3-dimensional power Doppler ultrasound––a preliminary study. J Chin Med Assoc. 2011;7:75–80. Conflict of interest This study was supported in part by Regione Autonoma della Sardegna (project code CPR-24750). Human rights statements and informed consent All procedures followed were in accordance with the ethical standards of the responsible Committee on Human Experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2008. Informed consent was obtained from all patients for being included in the study. Author information Authors and Affiliations Corresponding author About this article Cite this article Guerriero, S., Alcazar, J.L., Pilloni, M. et al. Reproducibility of two different methods for performing mean gray value evaluation of cyst content in endometriomas using VOCAL. J Med Ultrasonics 41, 325–332 (2014). https://doi.org/10.1007/s10396-013-0514-8 Received: Accepted: Published: Issue date: DOI: https://doi.org/10.1007/s10396-013-0514-8