Breast ductography

Breast ductography (a.k.a. galactography) is an imaging technique which is used to evaluate lesions causing nipple discharge. It helps in precisely locating the mass within breast tissue and gives useful information for surgical approach and planning.

Technique

A blunt-tipped sialogram needle (30-gauge) is used for performing the ductogram. The abnormal duct is identified and cannulated. Approximately 1-2 mL of contrast is injected. A standard two-view mammography (or craniocaudal and mediolateral projections) are obtained.

Indications

There is significant confusion about the indications of ductography. The primary indication is to evaluate a single duct which has a discharge. In cases where there are multiple discharging ducts or bilateral discharge, ductography is not indicated because the aetiology is systemic or physiological.

Procedure

The procedure takes patience and perseverance to perform successfully. It is generally not a painful procedure although patients are understandably apprehensive. The duct is identified by having the patient express the discharge. Under aseptic technique, the radiologist uses light and magnifier to perform the procedure. The contrast material injected into the duct can be mixed with methylene blue for preoperative assessment and localisation to aid the surgeon to locate the offending duct. In practice, when having difficulty visualising the duct opening, a single drop of contrast from the catheter can be used as a small drop magnifier on the skin. The duct opening should not be traumatised in the process of catheterisation.

Surgery

The majority of lesions found in ducts are intraductal papillomas. The practice holds that these lesions should be excised to exclude a malignant lesion. If the duct lesion is large enough, an ultrasound-guided percutaneous biopsy can make the diagnosis of a papilloma quite successfully. The duct is excised after it is filled with dye.

Radiographic assessment

Most of the intraductal abnormalities on mammography are identified as forms of filling defects. These can occur from both true pathological and artifactual (e.g. air bubble) causes. Other abnormal patterns include:

• fusiform or tubular dilatation of ducts: occurs with mammary duct ectasia

• abrupt ductal cut off: can occur with an obstructive distal lesion

Complications

• duct perforation: may lead to extravasation of contrast into the breast parenchyma

• pain or a burning sensation

• infection: galactography should not be performed when there is a purulent breast discharge

See also

• MR ductography