Potential role of strain elastography for detection of the extent of large-scar endometriosis.

OBJECTIVES: The purpose of this study was to evaluate the clinical value of strain elastography for detection of the lesion extent of large-scar endometriosis and compare it to conventional sonography and magnetic resonance imaging (MRI). METHODS: Eight patients suspected of having large-scar endometriosis underwent transabdominal sonography, strain elastography, and MRI. The mass was located and assessed for its size, imaging appearance, and, especially, widest boundary and vertical extent. After wide surgical excision and pathologic diagnosis, lesions in the central area shown on conventional sonography and the extended area shown on strain elastography underwent immunohistochemical examination. RESULTS: Nodules were always deep in the subcutaneous plane, in contact with the fascia or muscle. Horizontally, the mean lesion size shown on conventional sonography was mainly consistent with the size on MRI in all cases, but it was obviously smaller on sonography than on strain elastography in 7 cases. Vertically, the lesion depth was mainly consistent with the depth on MRI in 7 cases, but it was more infiltrative on strain elastography in 6 cases. The vertical and horizontal infiltration scales of the postoperative specimens were consistent with strain elastography in all cases. All 8 patients showed strong collagen type I expression in the central area of the lesions; 6 patients showed strong collagen type I expression and the other 2 showed moderate expression in the extended area. CONCLUSIONS: Strain elastography can elevate the diagnostic accuracy of large-scar endometriosis, the extent of which may be evaluated insufficiently by transabdominal sonography and MRI.