The homogeneously hypoechoic normal myometrium can be traversed by vessels that appear as anechoic areas. Corpus (39) and cervix (40) do not differ in echogenicity. Premenopausal, the height (H) of the endometrium (78) should be thinner than 15 mm, and postmenopausal thinner than 8 mm, unless the patient is on hormone replacement therapy. To avoid spuriously high measurement introduced by sectional obliquity, the endometrial height should only be measured on the longitudinal uterine section.
An intrauterine device (IUD) (92)
can be easily recognized by its total reflection with posterior shadowing (45) and should be within the fundic region of the uterine cavity. The distance of the IUD (d) from the upper end of the endometrium should be less than 5 mm and from the pole of the fundus (D) less than 20 mm (Fig. 59.4). An increase in these distances (Fig. 59.5) suggests an IUD that is dislocated toward the cervix (40) and provides inadequate contraception.
The normal uterus is demarcated by an echogenic serosa and exhibits a homogeneously hypoechoic myometrium (39). The most common benign uterine tumors, the fibroids (myomas), arise from the smooth musculature and are usually located in the corpus of the uterus. For planning the surgical enucleation of fibroids, it is relevant to distinguish intra-/transmural (Fig. 60.1) and submucosal (Fig. 60.2) fibroids from subserosal fibroids on the surface of the uterus (Fig. 60.3) (54). The submucosal location close to the uterine cavity can easily mistaken for endometrial polyps (65). Fibroids usually have a homogeneous or a concentrically lamellated echo pattern with distinct demarcation and a smooth surface, but can contain calcifications with corresponding acoustic shadowing or a central necrosis. The size of fibroids should always be measured and controlled by serial examinations to discover the rare sarcomatous transformation by revealing any rapid growth. Only in early pregnancy can a sudden increase in size be attributed to a benign lesion.
In menopause, hormone replacement therapy with estrogen can lead to estrogen producing ovarian tumors, or persistent follicles can induce endometrial hyperplasia (Fig. 60.4), which can eventually transform adenocarcinoma (54) if the high estrogen levels are maintained (Fig. 60.6). Malignant criteria include conspicuous endometrial thickness exceeding 15 or 8 mm (premenopausal and postmenopausal, respectively), a heterogeneous echogenicity, and an irregular outline (Fig. 60.6). A hypoechoic collection of blood ) in the uterine cavity (hema-tometra, Fig. 60.5) can be caused both by postinflammatory adhesions at the cervical os, for instance after conization, and by a cervix tumor.
The ovaries (91) are visualized on craniolaterally oriented sagittal sections and are frequently in the immediate vicinity of the iliac vessels (23) as seen in Figure 61.1. To measure the volume of the ovaries, a transverse section has to be added. The three diameters multiplied by 0.5 approximate the ovarian volume: in the adult female these volumes are between
5.5 and 10.0 cm3 for each ovary, with a mean value of just less than 8 cm3. The ovarian volume does not change during pregnancy, but decreases steadily by about 3.5 to 2.5 cm3 postmenopausal^, relating to the length of time after the menopause.
Was this article helpful?