3-D Doppler May Unmask Malignant Breast Lesions
ANN ARBOR, Mich., Oct. 21 (MedPage Today) -- Noninvasive distinctions between malignant and benign breast lesions emerged more clearly when evaluated by 3-D Doppler ultrasound, investigators here concluded.
In a group of women with suspicious breast lesions, 3-D power Doppler assessment of lesion vascularity had a 100% sensitivity and 86% specificity, Gerald L. LeCarpentier, Ph.D., of the University of Michigan, and colleagues reported in the November issue of Radiology.
If the results are borne out in larger studies, the imaging technique has the potential to spare some women from biopsies.
"Using speed-weighted 3-D power Doppler ultrasound, higher flow velocities in the malignant tumor-feeding vessels may be detected, whereas vessels with slower flow velocities in surrounding benign masses may be excluded," said Dr. LeCarpentier.
Despite extensive investigation, debate has surrounded Doppler's ability to reflect microvasculature and differentiate between malignant and benign breast lesions, the authors said.
Authorities generally agree that Doppler measures reflect overall vascularity, they continued. Additionally, some studies have suggested that flow velocities correlate with tumor size and that parameters such as vessel count and flow velocity can be used to identify malignant lesions.
However, previous studies generally have used two-dimensional rather than three-dimensional images to assess vascular morphology, density, and velocity distributions. Previously, Dr. LeCarpentier and colleagues found that speed-weighted pixel density derived from 3D Doppler images had accuracy similar to that of grayscale evaluation for distinguishing malignant from benign breast lesions.
More recently, the investigators found that evaluation of breast lesions with a handheld 3-D technique that incorporated multiple indices (including speed-weighted pixel density and gray scale) provided superior discrimination. They continued that investigation in the current study.
Speed-weighted 3-D Doppler flow measurement was combined with patient age and ultrasound gray scale information in the evaluation of 78 patients scheduled for breast biopsy for diagnosis of palpable or nonpalpable lesions. The study population included 38 patients from earlier research and an additional 40 patients for confirmation.
For each patient, a series of color Doppler images was acquired and reconstructed into a 3-D volume that encompassed the suspicious mass. By combining data from all 78 cases (46 benign and 32 malignant), the authors found that the area under the receiver operating characteristic curve (Az) confirmed previous research showing that speed-weighted pixel density performed best as a diagnostic index (P=0.01).
In the initial 38 patients and in the 40-patient confirmatory evaluation, the three-variable index of speed-weighted pixel density, age, and grayscale performed significantly better than any single variable (Az=0.97).
Setting the three-variable index to its maximum value resulted in a sensitivity of 100% and specificity of 86% in the 40-patient evaluation. The authors found that the performance was similar in both the 38-patient learning set and the test set.
"The enhanced diagnostic performance of three-dimensional Doppler-based multivariable indexes over grayscale [ultrasound] evaluation alone may eventually lead to the elimination of some biopsies," the authors concluded.
The authors noted that a limitation of the study was that the use of only one reader to draw the areas of interest may have introduced a bias.
The authors reported no disclosures.
Primary source: Radiology Source reference: LeCarpentier GL, et al "Suspicious breast lesions: assessment of 3D Doppler US indexes for classification in a test population and fourfold cross-validation scheme" Radiology 2008; 249: 463-470.
What breastcancer.org says about this article…
3-D Doppler May Unmask Malignant Breast Lesions
The small study reviewed here found that a type of three-dimensional (3-D) ultrasound picture of the breast can help doctors decide if a breast mass is cancer or not. The 3-D ultrasound method is called speed-weighted 3-D power Doppler and it shows blood flow in and around a breast tumor.
If a mass is found in your breast, your doctor usually will recommend a biopsy to figure out whether the mass is cancer or a non-cancerous abnormality. In some cases, the biopsy is done before any surgery is planned. In other cases, the biopsy is done during surgery and results are used to guide the type and extent of the surgery. If doctors had a very reliable non-surgical way to determine if a mass were cancer or not, some biopsies could be avoided.
In this study, 78 women who had a breast mass were scheduled to have a biopsy to figure out if the mass were cancer. Before any biopsies were done, each woman had a speed-weighted 3-D power Doppler of the breast area. The researchers decided if a mass were cancer based on how fast blood was flowing through the blood vessels in the mass. Breast masses with the fastest blood flow were classified as cancer. Masses with slower blood flow were classified as benign (non-cancerous). Then the researchers compared their classification of the masses based on speed-weighted 3-D power Doppler to classification of the masses based on the biopsy.
The results:
Thirty-two breast masses were cancer. All 32 masses that were classified as cancer based on biopsy also were classified as cancer based on the speed-weighted 3-D power Doppler results. So in this small study, speed-weighted 3-D power Doppler was perfect at identifying cancer when it was present.
Forty-six breast masses were benign. Of these 46 masses, 86% that were classified as benign based on biopsy also were classified as benign based on speed-weighted 3-D power Doppler. Speed-weighted 3-D power Doppler suggested that 14% of the masses were cancer but biopsy proved that that the masses weren't cancer. So speed-weighted 3-D power Doppler was very good but not perfect at identifying masses that weren't cancer.
Because speed-weighted 3-D power Doppler didn't misclassify any cancers, some day it may allow doctors to avoid biopsies or surgery in some women. Still, this is a small, early study and more research is needed before doctors can know for sure that speed-weighted 3-D power Doppler is completely reliable.
Stay tuned to Breastcancer.org for the latest research findings on new, better ways to prevent, diagnose, and treat breast cancer.
