How to Perform: Ductograms

By Shanmukha Srinivas, MD and Nooshin Najmi, MD

Breast ductography, also known as galactograms, are specialized imaging studies used to evaluate the ducts of the breast for pathological conditions such as papillomas, ductal carcinoma in situ (DCIS), or other ductal abnormalities. Ductography is currently less used in breast imaging and if mammography and sonography are unable to detect the underlying causes of pathological nipple discharge, contrast enhanced MRI is the next step, however breast MRI has some limitations such as low specificity, cost, and patient factors such as claustrophobia. Therefore, ductography still plays an essential role in the setting of pathologic nipple discharge with unremarkable conventional breast imaging. This guide provides a comprehensive overview of the procedure, including preparation, execution, and post-procedure care.

Step 1: Pre-Procedure

1. Patient Preparation
   • Indication: Confirm that the ductogram is indicated based on clinical findings, such as pathologic spontaneous nipple discharge. Patients with spontaneous nipple discharge which is unilateral and single-pore are appropriate candidates. Suspicious appearing discharge is serosanguineous, sanguineous, or clear. Ductography is used for diagnosis of the underlying condition, extent of disease, and will be a guidance for surgical excision.
   • Patient History: Obtain a detailed patient history and ensure there is no contraindications for the procedure (severe allergic reaction to iodinated contrast materials, a previous nipple surgery that would distort the underlying ducts, nipple retraction, which makes cannulation impossible, and mastitis or breast abscess)
   • Consent: Discuss the risks, benefits, and alternatives of the procedure with the patient. Obtain informed consent.
   • Preparation: Have the patient change into a gown and position them comfortably on the imaging table. To relax the periareolar sphincter muscle, a warm towel can be used on the center of the breast for 10–15 min. 
2. Procedure Room Setup
   • Ensure that all necessary equipment, including the mammography unit, contrast material, small 30-gauge straight blunt-tip cannula, high-intensity lamp, magnifying lens and sterile supplies, are ready.

Step 2: Pre-Procedure Imaging

• Scout Images: Take initial mammographic images including a craniocaudal, mediolateral and subareolar magnification view to assess for calcifications or masses. 

Step 3: Ductography Procedure

1. Positioning: Place the patient in the appropriate position for the ductogram, typically oblique supine position with the raised ipsilateral arm and the hand resting comfortably behind the patient’s head.
2. Identifying the orifice: Clean the nipple and areola, sterilize and then drape. Apply periareolar pressure to elicit discharge and identify which duct to cannulate. 
3. Ductal Cannulation
   • Local Anesthesia: Administer local anesthesia to the area around the nipple, if necessary, to minimize patient discomfort.
   • Cannulation: Using a sterile technique, insert a fine catheter (straight cannula or right-angled tip) into the duct of interest. The catheter is usually inserted through the nipple orifice. The catheter is then connected to extension tubing and a 1-3 mL syringe filled with full-strength iothalamate or iopamidol (both water-soluble).
4. Contrast Injection: Inject a small amount of contrast material into the duct through the catheter (0.2–0.3 mL). Stop injection if patient reports pain or radiologist feels resistance. Fix the catheter to the skin to prevent contrast leakage. 
5.  Imaging: Obtain mammographic images (Magnification views in lateral and craniocaudal views) of the duct system immediately after contrast injection to visualize the ductal anatomy and any potential abnormalities.
6. Image Evaluation
   • Review Images: Examine the images for the presence of filling defects, ductal irregularities, or other abnormal findings.
   • Additional Views: Obtain additional images such as rolled craniocaudal magnification views or mediolateral oblique view if needed to better characterize the findings or to visualize multiple ducts when there is overlap.

Step 4: Post-Procedure

1. Catheter Removal 
   • Carefully remove the catheter and ensure that there is no significant bleeding or discharge from the nipple.
2. Post-Procedure Care
   • Provide the patient with verbal and written instructions regarding any post-procedure care. Advise them to monitor for any unusual symptoms such as persistent discharge or pain.
   • Schedule follow-up imaging or evaluations if necessary based on the findings.

Step 5: Documentation and Follow-Up

1. Document the findings 
   • Complete a detailed report summarizing the procedure, the findings, and any recommendations for further management or follow-up. Follow-up pathology results.
2. Patient Instructions
   • Discuss the findings with the patient, providing clear explanations of the next steps or additional tests required based on the ductogram results.

Troubleshooting

1. Cannulating difficulties - Stabilize the nipple between thumb and forefinger while attempting cannulation. The nipple can also be angulated or rotated to provide more favorable obliquities for cannulation. Warm and moist washcloths can facilitate nipple relaxation and easier elicitation of discharge, which facilitates cannulation. 
2. Extravasation - The patient will often experience focal pain or burning. Remove the cannula, provide mild analgesia, and reschedule procedure in 7-14 days. 
3. Artifacts - remove air bubbles from cannula, syringe, and extension tubing. Implants, nipple reconstructive discs, silicone or saline implants, and silicone injections can all obscure ductographic findings.  

Case: 

42-year-old female with a history of spontaneous, clear right nipple discharge.

Figure 1. Example of a ductogram image showing contrast filling the ductal system with an intraductal lesion visible as a filling defect. The discharging duct in the central region of the nipple was cannulated with a right angled tip cannula and 0.15 cc of water soluble Conray contrast was injected. Magnified CC and ML views of the right subareolar region demonstrates opacification of the ductal system at 6 o'clock. There is mild dilatation of the immediate subareolar duct and sinus with abrupt termination of the duct approximately 18 mm deep to the nipple related to a small intraductal filling defect. The ducts beyond this filling defect are not opacified.

Figure 2. Example of a post ductogram subareolar breast ultrasound image demonstrating dilated duct with a small isoechoic avascular intraductal mass measuring 3 x 2 x 3 mm. The patient underwent surgical excision of this region which demonstrated benign intraductal papilloma.

References:

1. Slawson SH, Johnson BA. "Ductography: How to and What if?" Radiographics. 2001 Jan-Feb;21(1):133-50. doi: 10.1148/radiographics.21.1.g01ja15133. PMID: 11158649.
2. Alikhassi A, Curpen B. "Breast ductography: to do or not to do? A pictorial essay. Insights Imaging. 2023 Nov 23;14(1):201. doi: 10.1186/s13244-023-01547-x. PMID: 37995065; PMCID: PMC10667172.