NORMAL ANATOMY The primary indications for pelvic sonography are the evaluation of pelvic masses, pelvic pa in, and abnormal bleeding. Views of the pelvis are obtained transabdominally through a full urinary bladder and transvaginally with an empty bladder. These two methods complementeachotherand allow for complete evaluation of the pelvic organs(Table 28-1). Longitudinal and transverse views of the uterus, cervix, cul -de-sac, and adnexa are obta ined. Measurements of the uterus, ovaries, and any pathologic findings should be documented in three dimensions. The anteroposterior diameter of the en dometrium should be measured o a longitudinal view of the uterus. This measurement includes both layers of the endometrium( Fig. 28-1). Views of the kidneys are obtained to exdude hydronephrosis. Color Doppler is helpful in the evaluation of pelvic masses, especially in distinguishing between cysts and vessels, in documenting the solid nature of a lesion, andin the evaluation of ovariantorsion [28.11[28.21[28.31 Figure -28-1 Normal postmenarchal uterus. The uterine body (u)is la rger than the cervix(c)The endometrium(arrows) is the region of relatively bright central linear echoes. v, vagina Uterus Normal Uterus Normal uterine size va nes with age. Because of maternal hormone stimulation, the neonatal uterus is relatively large, with the body being larger than the cervix. The size rapidly decreases so that in early chi ld hood the uterus has a tubular shape with the uterine body being smaller than the cervix (1)( Fig. 28-2A and Fig. 28-2B) As the child approaches menarche, the uterine body again increases in size. In the postmenarchal period the body is typically twice the size of the cervix. he dimensions c of childbearing age is 8 x 4 x4 cm. The multiparous uterus is larger than the nul fiparous uterus by up to 1 am in each dimension Transabdominal view of the uterus in a 4-year-old girl. The cervix is larger than the body of the uterus. OSTMEN Figure-28-2b Transvaginal viewof the uterus in a postmenopa usal woman. The endometrium is a thin inear hyperechoic band (calipers). The patient also has prominent araate vessels(curved arrows The myometrium should be homogeneous with smooth ma gins. The arcuate vessels are in the periphery of the uterus and can be seen as a segmented hypoechoic band in the outer third of the myometrium(see Fig. 28-2A and Fig. 28-2B) The body of the uterus is separated from the cervix by the isthmus at the level of the intemal os. The uterus assumes a van ety of different positions descr bed in relation to the angle of the cervix to the vaginal (version )and the angle of body of the uterus at the isthmus(flexion). The most common position is anteverted Whenthe uterus is retroverted orretroflexed, it is difficultto evaluate transabdominallyand should be scanned with the vaginal probe( Fig. 28-3Aand Fig 28-3B) [284
NORMAL ANATOMY The primary indications for pelvic sonography are the evaluation of pelvic masses, pelvic pain, and abnormal bleeding. Views of the pelvis are obtained transabdominally through a full urinary bladder and transvaginally with an empty bladder. These two methods complement each other and allow for complete evaluation of the pelvic organs (Table 28-1) . Longitudinal and transverse views of the uterus, cervix, cul -de-sac, and adnexa are obtained. Measurements of the uterus, ovaries, and any pathologic findings should be documented in three dimensions. The anteroposterior diameter of the en dometrium should be measured on a longitudinal view of the uterus. This measurement includes both layers of the endometrium (Fig. 28-1) . Views of the kidneys are obtained to exclude hydronephrosis. Color Doppler is helpful in the evaluation of pelvic masses, especially in distinguishing between cysts an d vessels, in documenting the solid nature of a lesion, and in the evaluation of ovarian torsion. [28.1 ] [28.2 ] [28.3 ] Figure - 28-1. Normal postmenarchal uterus. The uterine body (u) is larger than the cervix (c) The endometrium (arrows) is the region of relatively bright central linear echoes. v, vagina. Uterus Normal Uterus Normal uterine size varies with age. Because of maternal hormone stimulation, the neonatal uterus is relatively large, with the body being larger than the cervix. The size rapidly decreases so that in early childhood the uterus has a tubular shape with the uterine body being smaller than the cervix (1) (Fig. 28-2A and Fig. 28-2B) . As the child approaches menarche, the uterine body again increases in size. In the postmenarchal period, the body is typically twice the size of the cervix. The dimensions of the normal uterus in women of childbearing age is 8 x 4 x 4 cm. The multiparous uterus is larger than the nulliparous uterus by up to 1 cm in each dimension. Figure - 28-2a. Transabdominal view of the uterus in a 4-year-old girl. The cervix is larger than the body of the uterus. Figure - 28-2b. Transvaginal view of the uterus in a postmenopausal woman. The endometrium is a thin linear hyperechoic band (calipers). The patient also has prominent arcuate vessels (curved arrows). The myometrium should be homogeneous with smooth margins. The arcuate vessels are in the periphery of the uterus and can be seen as a segmented hypoechoic band in the outer third of the myometrium (see Fig. 28-2A and Fig. 28-2B) . The body of the uterus is separated from the cervix by the isthmus at the level of the internal os. The uterus assumes a vari ety of different positions described in relation to the angle of the cervix to the vaginal (version) and the angle of body of the uterus at the isthmus (flexion). The most common position is anteverted. When the uterus is retroverted or retroflexed, it is difficult to evaluate transabdominally and should be scanned with the vaginal probe (Fig. 28-3A and Fig. 28-3B ) . [28.4 ]
Retroflexed uterus in a woman with intermenstrual bleeding. Transabdominal examination shows a retroflexed ute rus, but is difficult to evaluate the fundus and the endometrium. CLMP Figure-28-3b. Transvaginal examination shows a thickened endometrium that measures 18 mm(calipers)witha focal area of increased echogen icity (arrows)which was a polyp Transvaginal examination is necessary to completely evaluate the uterus in patients with retroverted or retroflexed uterus and to evaluate the endometrium in women with abnomal bleed ing. TH eous in echotexture with a hypoechoic central canal. Nabothian cysts are commonly seen in the cervixof older women. These cysts measure less than 2 cm and are usually anechoic, but occasionally conta in debris. They are probably caused by prior inflammation. uplication Anomalies Duplication anoma lies of the uterus occur in 0. 5% of women because of incomplete fusion of the mul lerian ducts(Table 28-2). In these cases, transa bdominal scanning is valuable in identifying the degree of separation of the uterine horns and defining the extemal uterine contour. Endovaginal scanning during the secretory phase(when the endometrium is most prominent )is helpful in defining two separate endometrial stripes. In subtle cases, magnetic resonance imaging often is helpful in delineating the type of duplication anomaly. Duplication a nomal ies usually are asymptomatic Conditions associated with these anomal ies indude the following: an increased incidence of spontaneous bortionand pregnancy complications( 2) an obstructed duplicated hom that presents as a pelvic mass; and renal anomalies, especially unilateralrena agenesis(3)(Fig. 28-4A and Fig. 28-4B) Figure-28-4a Bicomuate uterus. Transabdominal transverse vew of the uterus demonstrates two homs that are widely separated. Only one cervix was seen on vaginal scanning
Figure - 28-3a. Retroflexed uterus in a woman with intermenstrual bleeding. Transabdominal examination shows a retroflexed uterus, but is difficult to evaluate the fundus and the endometrium. Figure - 28-3b. Transvaginal examination shows a thickened endometrium that measures 18 mm (calipers) with a focal area of increased echogenicity (arrows) which was a polyp. Transvaginal examination is necessary to completely evaluate the uterus in patients with retroverted or retroflexed uterus and to evaluate the endometrium in women with abnormal bleeding. The cervix is homogeneous in echotexture with a hypoechoic central canal. Nabothian cysts are commonly seen in the cervix of older women. These cysts measure less than 2 cm and are usually anechoic, but occasionally contain debris. They are probably caused by prior inflammation. Duplication Anomalies Duplication anomalies of the uterus occur in 0.5% of women because of incomplete fusion of the müllerian ducts (Table 28-2 ) . In these cases, transabdominal scanning is valuable in identifying the degree of separation of the uterine horns and defining the external uterine contour. Endovaginal scanning during the secretory phase (when the endometrium is most prominent) is helpful in defining two separate endometrial stripes. In subtle cases, magnetic resonance imaging often is helpful in delineating the type of duplication anomaly. Duplication anomalies usually are asymptomatic. Conditions associated with these anomalies include the following: an increased incidence of spontaneous abortion and pregnancy complications (2) ; an obstructed duplicated horn that presents as a pelvic mass; and renal anomalies, especially unilateral renal agenesis (3) (Fig. 28-4A and Fig. 28-4B) . Figure - 28-4a. Bicornuate uterus. Transabdominal transverse view of the uterus demonstrates two horns that are widely separated. Only one cervix was seen on vaginal scanning
42e Figure -28-4b (B)View of the right renal fossa demonstrates an absent right kidney. 签 endometrium The endometrium is visualized as a hyperechoic band in the centerof the uterus. The total thickness of the endometrium re presents the anterior a nd posterior opposed layers. Endovaginal scanning is required to optimally visualize the endometrium. [28.5 ] When endometrial fluid is present, this should not be included in the endometrial thickness measurement. The hypoechoic la yer around the endometrium represents an inner compact layer of myometrium and should not be included in endometrial thickness measurements (4) Normal endometrial thickness and appea rance varies with the phase of the menstrual cycle (5)( Fig. 28-5A, Fig. 28-5B and Table 28-3). During the menstrual hase, hypoechoic mate rial can be seen centrally, which represents blood and tissue. In the proliferative phase the endometrium has the appea rance ofthree lines ith an echogenic central line surrounded by a more hypoechoic layer, with a peripheral hyperechoic layer. In the late secretory phase, the endometrium is at its greatestthickness, with homogeneously increased echogenicity and increased through transmission (6) ure-28-5a Normal endometrium. "Triple line"e ndometriumin midcycle Secretory phase endometrium that is thick and echogenicwith postenor acoustic enhancement Fallopian Tub The normal fallopiantube is difficult to distinguish from surrounding vessels and ligaments. It usually is not visualized unless abnormal or surrounded by fluid Ovarian Size Ovaries in girls younger than 2 years of age are typically less than 1 mL in volume, although in neonates they can be slightly larger. Recent literature also
Figure - 28-4b. (B) View of the right renal fossa demonstrates an absent right kidney. Endometrium The endometrium is visualized as a hyperechoic band in the center of the uterus. The total thickness of the endometrium represents the anterior a nd posterior opposed layers. Endovaginal scanning is required to optimally visualize the endometrium. [28.5 ] When endometrial fluid is present, this should not be included in the endometrial thickness measurement. The hypoechoic layer around the endometrium represents an inner compact layer of myometrium and should not be included in endometrial thickness measurements. (4) Normal endometrial thickness and appearance varies with the phase of the menstrual cycle (5) ( Fig. 28-5A , Fig. 28-5B , and Table 28-3 ). During the menstrual phase, hypoechoic material can be seen centrally, which represents blood and tissue. In the proliferative phase, the endometrium has the appearance of three lines with an echogenic central line surrounded by a more hypoechoic layer, with a peripheral hyperechoic layer. In the late secretory phase, the endometrium is at its greatest thickness, with homogeneously increased echogenicity and increased through transmission. (6) Figure - 28-5a. Normal endometrium. "Triple line" endometrium in midcycle. Figure - 28-5b Secretory phase endometrium that is thick and echogenic with posterior acoustic enhancement. Fallopian Tube The normal fallopian tube is difficult to distinguish from surrounding vessels and ligaments. It usually is not visualized unless abnormal or surrounded by fluid. Ovaries Ovarian Size Ovaries in girls younger than 2 years of age are typically less than 1 mL in volume, although in neonates they can be slightly larger. Recent literature also
documents in these young girls the pres cysts, which usually are less than 5 mm(with the exception of neonates, where they may be larger than 1 am). (7-9) The ovaries increase in size in prepubertal girls with follicles up to 1 cm in size. After menarche the ovaries are ovoid in shape and generally measure 3 x 2 x 1 to 2 am(Fig. 28-6). Follides typically are present. a study of ova rian size in women ofmenstrual age reveals a mean ovarian vol ume of 10 ml(10)(Table 28-4) lists the size and appearance of ovaries with respect to patientage [28.2 1 Figure -28-6 Normal ovary with multiple small follide Ovarian Cysts In the prolife rative phase ofthe menstrual cycle, multi ple small foldes are visualized, usually 1 am in diameter or less. A dominant foll icle develops in the mid cyo which measures up to 2 cm in diameter. After ovulation, the corpus luteumcyst develops [28.6] This frequently contains hemorrhage and hasa complex appearance (Table 28-5)descri bes the appearance ofovary follicles with respect to phase of the menstrual cycle. (Table 28-6)lists the various appearances of varian cystsare common in all age groups, but especially in women of menstrual age. Anechoic b enign cysts are completely anechoic with enhanced through transmission. They have a thin wall no septations, and no solid elements. Because dominant fol lices and luteal cysts frequendy are up to 3 cm in size. benign-appearing lesions in this size range require no follow-up Hemorrhagic cysts have a more complex appearance(see Table 28-6)with internal septation and retractile dot(Fig. 28-7).[28.7 However, if a cyst is small (less than 3 cm)and has the dassic appearance of a hemorrhagic cyst, it can be treated as a benign cyst and therefore does not requ ire follow-up Figure -28-7 Hemorrhagic cyst. Transva ginal view of the right ovary demonstrates a cyst with multiple internal echoes and strands of internalechoes. This is the classicappearance of a hemorhagiccyst. If a lesion has a questionable appearance or is larger than 3 am, serial scans are helpful since hemorrhagic cysts undergo rapid change of intemal cha racteristics A follow-up sonogram in 6 weeks(when the patient is at a different phase of the menstrual cycle)typically demonstrates resolution of the cyst For la rge lesions. ormonal therapy frequently is used to suppressfollicular activity and the development of new cysts(Table 28-7) Free fluid A small amount of fluid is present in the cul-de-sac of asymptomatic women throughout the menstrual cycle. The largest quantity of normal free fuid occurs after the mature fol licle ruptures in the midcyde, (11)but fluid also is seen during menstruation and can be visualized throughout the cycle from serosal transudate from the ovary or other peritoneal organs (12) Complex fluid(with debris or septations)is a and results from hemorhage, infection, or neoplasm SONOGRAPHIC PITFALLS Extrauterine Solid Pelvic Masses A variety of nonovarian tumors and other a bnomalities can masque rade as solid ovarian masses (Table 28-8). The most of these is the pedunculated fibroid(Fig. 28-8A and Fig. 28-8B). This diag nosis is made sonographic lly when the ovaries are seen separate fom the otherwise suspicious -a ppeanng mass A stalk can be present connecting the pedunculated fibroid to the uterus. Magnetic resonance imaging is helpful in difficult cases. Nongynecologic cond itions that
documents in these young girls the presence of cysts, which usually are less than 5 mm (with the exception of neonates, where they may be larger than 1 cm). (7-9) The ovaries increase in size in prepubertal girls with follicles up to 1 cm in size. After menarche, the ovaries are ovoid in shape and generally measure 3 x 2 x 1 to 2 cm (Fig. 28-6 ). Follicles typically are present. A study of ovarian size in women of menstrual age reveals a mean ovarian volume of 10 ml. (10) (Table 28-4 ) lists the size and appearance of ovaries with respect to patient age. [28.2 ] Figure - 28-6. Normal ovary with multiple small follicles. Ovarian Cysts In the proliferative phase of the menstrual cycle, multiple small follicles are visualized, usually 1 cm in diameter or less. A dominant follicle develops in the midcycle, which measures up to 2 cm in diameter. After ovulation, the corpus luteum cyst develops. [28.6] This frequently contains hemorrhage and has a complex appearance. (Table 28-5 ) describes the appearance of ovary follicles with respect to phase of the menstrual cycle. (Table 28-6 ) lists the various appearances of hemorrhagic cysts. Ovarian cysts are common in all age groups, but especially in women of menstrual age. Anechoic benign cysts are completely anechoic with enhanced through transmission. They have a thin wall, no septations, and no solid elements. Because dominant follicles and luteal cysts frequently are up to 3 cm in size, benign-appearing lesions in this size range require no follow-up. Hemorrhagic cysts have a more complex appearance (see Table 28-6 ) with internal septations and retractile clot (Fig. 28-7 ) . [28.7 ] However, if a cyst is small (less than 3 cm) and has the classic appearance of a hemorrhagic cyst, it can be treated as a benign cyst and therefore does not require follow-up. Figure - 28-7. Hemorrhagic cyst. Transvaginal view of the right ovary demonstrates a cyst with multiple internal echoes and strands of internal echoes. This is the classic appearance of a hemorrhagic cyst. If a lesion has a questionable appearance or is larger than 3 cm, serial scans are helpful since hemorrhagic cysts undergo rapid change of internal characteristics. A follow-up sonogram in 6 weeks (when the patient is at a different phase of the menstrual cycle) typically demonstrates resolution of the cyst. For large lesions, hormonal therapy frequently is used to suppress follicular activity and the development of new cysts (Table 28-7 ) . Free Fluid A small amount of fluid is present in the cul-de-sac of asymptomatic women throughout the menstrual cycle. The largest quantity of normal free fluid occurs after the mature follicle ruptures in the midcycle, (11) but fluid also is seen during menstruation and can be visualized throughout the cycle from serosal transudate from the ovary or other peritoneal organs. (12) Complex fluid (with debris or septations) is abnormal and results from hemorrhage, infection, or neoplasm SONOGRAPHIC PITFALLS Extrauterine Solid Pelvic Masses A variety of nonovarian tumors and other abnormalities can masquerade as solid ovarian masses (Table 28-8 ) . The most common of these is the pedunculated fibroid (Fig. 28-8A and Fig. 28-8B ) . This diagnosis is made sonographically when the ovaries are seen separate from the otherwise suspicious-appearing mass. A stalk can be present connecting the pedunculated fibroid to the uterus. Magnetic resonance imaging is helpful in difficult cases. Nongynecologic conditions that
may mimic solid ovarian masses include pelvic kidney (Fig. 28-9A), diverticulitis(see Fig. 28-9B), rectosigmoid cardinoma, vascular masses, pelviclymph nodes an inflamed appendix, and pelvichematomas. Pedunculated fibroid Transabdominal view of the pelvis demonstrates a mass(M)adjacentto the uterus Transvaginal examinationdemonstrates a tissue plane between the uterusand the mass. Mimics of solid adnexal masses. Pelvic kidney Transvaginal view of the uterus (U) with a mass(K)seen behind the uterus with a tissue plane between the two. Echogenic fat (arrows )can be seen in the center of this pelvic kidney. Diverticulitis. Transvaginal view in the left pelvis shows a hypoechoicmass arising from sigmoid colon in this patient with diverticulitis. Extrauterine Cystic Pelvic Masses
may mimic solid ovarian masses include pelvic kidney (Fig. 28-9A ), diverticulitis (see Fig. 28-9B ) , rectosigmoid carcinoma, vascular masses, pelvic lymph nodes, an inflamed appendix, and pelvic hematomas. Figure - 28-8a. Pedunculated fibroid. Transabdominal view of the pelvis demonstrates a mass (M) adjacent to the uterus (U). Figure - 28-8b. Transvaginal examination demonstrates a tissue plane between the uterus and the mass. Figure - 28-9a. Mimics of solid adnexal masses. Pelvic kidney. Transvaginal view of the uterus (U) with a mass (K) seen behind the uterus with a tissue plane between the two. Echogenic fat (arrows) can be seen in the center of this pelvic kidney. Figure - 28-9b. Diverticulitis. Transvaginal view in the left pelvis shows a hypoechoic mass arising from sigmoid colon in this patient with diverticulitis. Extrauterine Cystic Pelvic Masses