The role of ultrasound

Ovarian Cyst Miracle

Ovarian Cyst Miracle System By Carol Foster

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Ultrasound is an extension of the clinical examination in gynaecology; it is unlikely that a woman with a normal pelvic examination and negative ultrasound has a significant gynaecological abnormality. Ultrasound should only be used when there is a clinical question to be answered. Incidental findings such as ovarian cysts are not uncommon in asymptomatic women and if ultrasound findings are taken in isolation they can be misleading.

Investigation of pelvic mass

Ultrasound is of paramount importance in evaluating a suspected pelvis mass. It is particularly useful when the mass is notwell defined or when pelvic examination is limited by discomfort or patient habitus. The assessment of a pelvic mass is a good demonstration that neither the TA or TV route of examination should be used at the exclusion of the other; rather the two techniques are complimentary. The TA route allows for assessment of large tumours (beyond the range of the vaginal probe), evaluation of their relationship to other organs and assesses the presence of ascites. More detailed morphological assessment of a mass is better with transvaginal scan (TVS).

ENLARGED UTERUS

The commonest pathology seen on scanning the non-pregnant uterus is the presence of uterine fibroids. The vast majority lie within the myometrium, though some can be pedunculated or lie within the broad ligament.

Ultrasound Hypoechoic Myometrium
Fig. 36.1 Longitudinal section of a uterus, with a large posterior wall subserosal fibroid, with characteristic shadowing.
Ultrasound Hypoechoic Myometrium
Fig. 36.2 Transverse section of a uterus showing bilateral intramural fibroids.

• Intramural - Within the myometrium without distorting the endometrial cavity or serosal surface.

• Submucous - Distort the endometrial cavity.

• Subserous - Distort the serosal surface. Ultrasound helps define the number and size of fibroids and also their situation within the myometrium. In the majority of patients with fibroids there are multiple tumours. Ultrasound features of fibroids are that they are well circumscribed lesions that appear hypoechoic compared to the surrounding myometrium. They may contain foci of calcification with characteristic shadowing (Figs 36.1 and 36.2).

If a fibroid is pedunculated it is sometimes difficult to differentiate from a solid ovarian tumour. The demonstration of two normal ovaries or the use of Doppler to demonstrate that the blood supply originates from the uterus would identify the lesion as uterine in origin.

Ultrasound diagnosis of fibroids and their location helps to determine the relationship to presenting symptomatology, what treatment modalities are suitable and also for monitoring treatment in cases where gonadotrophin-releasing hormone (GnRH) analogues are used to shrink fibroids.

Leiomyosarcomas are the malignant counterpart of benign fibroids, and ultrasound can not reliably be used to determine sarcomatous change, although a change within the vascular pattern may be detected using Doppler.

OVARIAN CYSTS

The primary value of ultrasound in the management of ovarian cysts is to differentiate between a physiological cyst and a pathological cyst, and how likely it is that any pathological tumour is malignant. Several studies have concluded that ultrasound is the best imaging technique for the assessment of ovarian cysts. The following information should be gained from an ultrasound examination of an ovarian tumour.

• The side of the lesion unilateral or bilateral.

• The size - three dimensions if possible.

• Consistency - cystic or solid (size and regularity of solid components).

• Internal structures - unilocular, multilocular, complex. Nature of septa thin/thick.

• Internal wall - smooth, irregular presence of papillary projections, (solid projections into the cyst cavity from the cyst wall >3 mm in height).

• Echogenicity - in comparison to myometrium.

It is suggested that certain ultrasound features can be used to predict histological diagnosis [1]. Dermoid cysts are a good example and they are easily recognized on ultrasound owing to their fat and hair content. The most characteristic feature is the presence of a 'white ball' in the corner of the cyst (Fig. 36.3); this corresponds to hair and sebum. Hair that is free within the cyst shows as long echoic lines. There is often significant shadowing making it difficult to assess accurately the size of the cyst.

Endometriomas tend to be unilocular and have an echogenic ground glass appearance. Experienced gynaecological ultrasonographers can reliably differentiate benign from malignant cysts and are probably better at predicting malignancy than mathematical models [2]. Ultrasonic signs of malignancy include multilocular or multiple cysts, thick or irregular septa or cyst walls, papillary projections and the presence of solid components. [3]

Dermoid Cyst Benign Ultrasound
Fig. 36.3 A dermoid cyst showing characteristic appearance of hair and sebum as a "white ball".
Dermoid Cyst Malignant Ultrasound
Fig. 36.4 A mucinous cystadenocarcinoma showing multiple locules.

The more complex a tumour, that is, the more septa and solid components it contains, the higher the risk of malignancy. Granberg et al. 1989 [4] found the frequency of malignancy in unilocular cysts to be 0.3% while in multilocular solid cysts it was 73% (Figs 36.4 and 36.5). Colour flow Doppler has been shown to be a useful adjunct in assessing the possibility of malignancy in ovarian tumours. The Doppler criteria for diagnosing malignancy are not clearly defined; however, malignant tumours will generally have lower blood flow impedance and higher blood flow velocity. This is due to the paucity of smooth muscle in the walls of blood vessels and the presence of arterio-venous shunting.

Sonographic findings can be used in conjunction with menopausal status/age and serum CA125 levels to give

Ovarian Cyst
Fig. 36.5 The same cyst showing separate measuring 4.2 mm.
Normal Ovarian Ultrasound Images
Fig. 36.7 Ovarian cysts showing the differing appearances of a haemorrhage. Figure 7 shows organised dot mimicking a solid component.
Ovarian Cyst
Fig. 36.6 A simple bilocular cyst, which is sonorlucent with normal surrounding ovarian tissue.

score on the risk of malignancy index (RMI); this can be used as a triage for suspected ovarian cancers.

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