Diagnostic Imaging Online
November 10, 2003
Digital subtraction plus digital mammography equals improved diagnosis
Researchers have applied an old technique to a new imaging technology to create a possibly more powerful way to diagnose breast cancer.
The old technique is contrast-enhanced digital subtraction angiography, a method first proposed 20 years ago to fluoroscopically diagnose breast cancer. That strategy never gained acceptance, but now the combination of DSM and full-field digital mammography may prove clinically useful.
Dr. John M. Lewin, a professor of radiology, and colleagues at the University of Colorado Health Sciences Center performed DSM in 26 patients who had either mammographic or clinical findings necessitating biopsy. The patients received both low- and high-energy exposures on a full-field digital scanner during one breast compression in the mediolateral oblique projection. After compression, the researchers administered iodinated contrast, compressed the breast again, and repeated the exposures.
During image processing, they created dual-energy images highlighting the iodine by using weighted subtraction of the logarithm of the low-energy image from the high-energy image.
The technique highlighted invasive cancers in 13 of the subjects. Lewin and colleagues reported that 11 of the 13 tumors exhibited strong enhancement, one showed moderate enhancement, and the final one demonstrated weak enhancement. Ductal carcinoma in situ showed weak enhancement in one patient, while 12 patients had benign tissue. Two of the subjects with benign tissue showed diffuse enhancement, and weakly focal enhancement was seen in two other patients.
The study was published in the October 2003 issue of Radiology.
Lewin cautioned that the study was small, with only one cancer that was both nonpalpable and mammographically occult. He was unsure how the technique would perform for totally occult cancers.
“My hope is for a high-risk screening study, not so much to prove that you can use it for high-risk screening, but to see if it can detect otherwise occult cancers and to see what the true false-positive rate is in young women with active breast tissue,” he said.
For more information from the Diagnostic Imaging online archives:
Full-field digital mammography stands up to clinical comparison
Dual-energy contrast protocol offers new tool to detect breast cancer
-- By Merlina Trevino
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