There are numerous reasons why a radiologist may elect to ask for additional views or ultrasounds after reading your mammogram. They are viewing a three-dimensional object in two dimensions. Overlapping tissue can create densities on the mammogram that appear as a mass or area termed “architectural distortion.”
The main reasons a patient may be called back are for areas of architectural distortion, masses or grouped microcalcifications, which are tiny spots of calcium in the breast.
Mammograms are categorized into groups termed BI-RADS, or Breast Imaging Reporting and Data System. BI-RADS 1 is negative; BI-RADS 2 is benign; BI-RADS 3 is probably benign; BI-RADS 4 is suspicious; BI-RADS 5 is highly suspicious and BI-RADS 0 is incomplete, requiring additional imaging including additional views, with or without spot compression, spot magnification views – typically for microcalcifications – and ultrasound. The focus here is on the BI-RADS 0.
Architectural Distortion: This is a very common occurrence but a potential sign for a true lesion. Additional views with slightly different projections and particularly spot compression views are utilized for evaluation of this abnormality. The spot compression views spread the overlapping tissue and remove the summation artifact if there is no true lesion. If a persistent abnormality is seen, an ultrasound is commonly requested to exclude an underlying lesion in the breast. The majority of the time, there is no lesion, and routine follow-up may be performed.
Masses: Doctors typically ask for spot compression views and ultrasound on any new mass or enlarging mass from prior mammograms. The spot compression views give an idea of the borders of the lesion with smooth borders typically indicating benign lesions such as cysts and benign fibroadenomas (non-cancerous tumors), whereas irregular borders are more worrisome and may indicate a more aggressive lesion. Ultrasound is then performed after the spot compression views for evaluation of the consistency of the lesion, primarily cystic or solid.
In addition, the vascularity of the lesion can be assessed with the color Doppler with the more vascular lesions typically being more aggressive. Cysts do not contain internal vascularity. Cysts typically do not require any further follow-up unless they are painful or they may be aspirated under ultrasound guidance. The vast majority of solid lesions are benign fibroadenomas, but an ultrasound guided biopsy may be necessary for confirmation of the pathology. Short-term ultrasound follow-up may also be performed.
Microcalcifications: The vast majority of microcalcifications are benign and typically either secretory or dermal (within the skin). Vascular calcifications in the arteries of the breasts may also present as microcalcifications. Spot magnification views are performed to determine the number and shape of the microcalcifications. Rounded, well-defined calcifications are almost always benign and compromise the vast majority of our findings. Irregular sharp or serpiginous microcalcifications – particularly if they are numerous and tightly grouped – generally require a biopsy, which may be performed with stereotactic technique and local anesthesia or may be performed with open technique with needle localization for the surgeon, who then completely removes the microcalcifications for pathologic evaluation. Stereotactic technique is much simpler and is used the vast majority of the time for these calcifications.
Over 95 percent of the BI-RADS 0 mammograms turn out to be benign. Having said this, it is crucial not to ignore the recommendations of returning to the radiology department for additional views or ultrasounds, as early detection and treatment of the worst case scenario – breast cancer – results in cure.