In addition to visualizing normal tissue, imaging
studies of the uterine cavity can also show
the presence of reactive, inflammatory, benign
and malignant neoplastic tissue. Structural abnormalities
of the uterus are an important cause
of infertility, recurrent pregnancy loss and poor
reproductive outcomes (
Recently, three-dimensional extended imaging (3DXI), which is a powerful computed processing technique similar to CT and MRI has provided the ability to obtain sequential sections of acquired volume scans in A, B and C planes. Image thickness in the series can be manipulated by fractions of a millimeter to a few millimeters and the interval of slices varies in the accordance with the area of interest and is dependent upon the volume size. The pictures can be obtained in the form of a contiguous series of thin slices [multi-slice (MS) view] or strong multi-resolution images. Here, we briefly discuss the technique of saline infusion sonography, followed by a review of the 3DXI sonohysterographic characteristics of intrauterine lesions such as polyps, leiomyomas, hyperplasia, and intra-cavitary adhesions.
The examination is typically scheduled in the early follicular phase of the menstrual cycle, immediately after cessation of menstrual flow and before day ten. The endometrium is relatively thin during the early proliferative phase of the cycle, which facilitates imaging interpretation. In the late luteal phase of the cycle, thickened endometrium or focal irregularities in the endometrial outline may be mistaken for endometrial hyperplasia or small polyps.
Prophylactic antibiotics are not administered unless there is a history of chronic pelvic inflammation. The majority of patients can tolerate the procedure and anesthesia or analgesia is not usually required for catheter insertion. In cases that experience some cramping, a nonsteroidal anti-inflammatory medication such as ibuprofen (400 mg) is prescribed 30 minutes prior to the examination.
A preliminary transvaginal sonography is recommended to investigate the uterus and adenexes for any abnormal findings. The procedure must be performed under strict conditions since saline, after it passes the genital tract, may introduce infection into the peritoneal cavity.
A suitable sized speculum is inserted into the vagina and the cervix is cleaned with antiseptic solution. A Foley 6-Fr pediatric bladder drainage catheter (Supa Co., Tehran, Iran) is introduced into the cervical canal and a balloon at the catheter tip is placed in the lower uterine segment or cervical canal and inflated with 1 mL of sterile saline solution. The speculum is removed and a covered vaginal probe is inserted. Under sonographic guidance, sterile normal saline solution (5-10 mL) is slowly introduced into the cavity. Three-dimensional ultrasound volume scanning is then performed using a high-resolution three-dimensional ultrasound machine (5-8 MH probe, Accuvix XQ, Medison, Korea). When optimal distention of the endometrial cavity is achieved, a three-dimensional volume sweep of the sagittal and transverse planes of the uterus are performed. Scanned volumes are evaluated in multi-planar three-dimension and MS view mode with a slice interval of 0.5-0.6 mm.
Since the distended balloon may obscure pathology it is deflated immediately before the end of the procedure, after which the catheter is slowly withdrawn while adding more fluid to ensure adequate visualization of the lower uterine segment and cervical canal. Offline analyses of uterine morphology and the endometrial cavity are performed in a reconstructed coronal plane. Uterine structure, particularly the contour of the uterine fundus and any focal or diffuse endometrial or subendometrial abnormalities are analyzed in each patient. Congenital uterine anomalies, if present, are classified according to the American Fertility Society Classification.
Endometrial polyps that appear as a solitary or
multiple, diffuse or focal, sessile or pedunculated
thickening of the endometrium are the most common
anomalies visualized on sonohysterography.
An endometrial polyp may occur either alone,
in the setting of endometrial hyperplasia or less
commonly, carcinoma (
3D-MS- View of endometrial outline in the transverse plane shows a localized lesion (2×3, slice interval 0.6 mm). A. Optimal image of the lesion is obtained by scrolling the parallel planes of volume. B. a/b ratio <1 indicating " pedunculated" lesion. C. Coronal reconstructed view confirmed the pedunculated polyp. D. a/b ratio≥1 indicating " sessile" lesion. " a" is the maximum diameter of the base of the lesion at the level of the endometrium and " b" is the maximum transverse diameter of the lesion.
Leiomyomas are the most common benign
pelvic tumors of the female genital tract, occurring
in 20-25% of reproductive-age women
At sonohysterography, submucosal myomas
can be classified into three grades according to
the following double criteria (
3D-MS-SHG shows a submucousal myoma in longitudinal section of the uterus. A. Completely intracavitary fibroid, pedunculated, without intramural extension, angle ≤20˚. B. Protrusion index (>50% and angle≤90˚) suggestive of Type I submucous myoma. C. Protrusion index (<50% and angle>90˚) suggestive of Type II submucous myoma. (a) The intramural component of the myoma and, (b) the myoma component protruding into the cavity. The protrusion index is calculated by [(b/a+b) ×100].
Endometrial hyperplasia is a proliferative disorder of
the endometrium that usually results from unopposed
estrogenic stimulation, which causes post-menopausal
bleeding in 4-8% of cases (
A-C. The sonohysterogram shows focal and asymmetric thickening of endometrium measuring 10 mm , presenting with smooth and spiky (cauliflower) surface. Three-dimensional rendering demonstrates better visualization. This patient had excessive bleeding. Histopathology following dilatation and curettage confirmed endometrial hyperplasia.
Endometrial hyperplasia may be suspected sonographically.
The principal findings are a thickness of
>15 mm or >8 mm after menopause and the presence
of a non-homogenous echo pattern with microcystic
changes. On sonohysterography, endometrial hyperplasia
and carcinoma generally appear as an irregular,
thickened, heterogeneous endometrium, which is
often diffusely distributed (
Uterine synechiae or adhesions that are clinically
present with infertility, recurrent abortion, and
reduced menstrual flow may be minor and affect
a small area of the uterine wall or extensive with
diffuse involvement and obliteration of a large part
of the uterine cavity. Synechiae are categorized as
mild, moderate, or severe, according to whether
adhesions involve one-fourth, one-half, or over
three-fourths of the uterine cavity. On an ultrasound
of a patient with Asherman’s syndrome, the
adhesions usually appear as endometrial irregularities
or hyperechoic bridges within the endometrial
cavity. Three-dimensional ultrasound demonstrates
a significant reduction of the endometrial
cavity volume in all reformatted sections. With
sonohysterography, adhesions are usually seen as
echogenic (similar to the myometrium), mobile
and thin or thick strands of tissue that cross the
endometrial cavity, attaching to both uterine walls
Strands of tissue cross the endometrial cavity; suggestive of endometrial synechiae. A. Sagital and coronal view of mild synechiae. Coronal section shows adhesions involve one-fourth of the uterine cavity (arrows). B. Moderate synechiae; Coronal section demonstrates adhesion involves about one-half of uterine cavity. C. Severe synechiae, Coronal section represents adhesion involves about three-fourths of uterine cavity.
Although hysteroscopy is the gold standard in the detection of intrauterine pathologies, particularly in patients with infertility, three-dimensional MS sonohysterography (3D-MS-SHG) offers a good overall agreement with diagnostic hysteroscopy over conventional three-dimensional multi-planar views. Uterine volume sampling, simultaneous analysis of three orthogonal planes and rendering of images allow better estimation of shape, size, location and protruding degree of endometrial lesions. 3D-MS-SHG, as a less invasive and more cost effective alternative to diagnostic hysteroscopy, is a reliable, accurate method that should be considered for precise pre-operative assessment.