Gynecologic Sonography: Uterus, Ovaries, and Adnexa
Uterus and endometrium
Measure the uterus in sagittal and transverse planes and describe version, flexion, and contour. Endometrial thickness is the maximal anteroposterior double-layer measurement in a true sagittal plane. In reproductive-age patients values vary with phase, from thin in the early follicular phase to 8–15 mm in the late secretory phase. In postmenopausal bleeding, a thickness of 4 mm or less is generally reassuring, while a thicker, heterogeneous endometrium with irregular margins raises concern for carcinoma, particularly with tamoxifen use. Differentiate fibroids (well-defined, hypoechoic, shadowing, peripheral flow) from adenomyosis (globular uterus, asymmetric myometrial thickening, small myometrial cysts, fan-shaped shadowing, question-mark sign). Polyps appear as echogenic intracavitary masses, sometimes with a feeding stalk vessel.
Ovaries and adnexa
A simple cyst is anechoic, thin-walled, and shows posterior acoustic enhancement; it may be followed rather than aspirated. A hemorrhagic cyst shows a reticular, lacy internal network without internal flow. An endometrioma shows homogeneous low-level echoes - ground glass. A mature teratoma shows an echogenic Rokitansky nodule with acoustic shadowing and fat. Torsion produces an enlarged ovary with peripherally displaced follicles and may show a whirlpool sign; arterial flow can persist, so normal Doppler does not exclude torsion. Hydrosalpinx appears as a folded tubular structure with incomplete septa; a tubo-ovarian abscess is a complex mass with debris.
Rule of thumb
Use internal vascularity, not echogenicity alone: reticular hemorrhagic cysts and ground-glass endometriomas are avascular internally, while a solid nodule with internal flow is not.