by
Sean Ruck, Contributing Editor | August 07, 2014
From the July 2014 issue of HealthCare Business News magazine
Cutting down on false negatives and false positives
In order to better understand why 3-D mammo is getting so much support, it’s necessary to understand the technology. Harvard’s Kopans offered a simple explanation. “Conventional 2-Dimensional mammography is like a book with clear pages. You can hold the book up to the light and see all the words, but they are superimposed and hard to read,” he said. “Normal breast tissue superimposes on cancers and can hide them. Superimposed normal breast tissue can also fool the radiologist into thinking that there is a cancer when there is none. DBT allows the radiologist to see each individual page free from what is in front and what is behind. This allows us to find more cancers, and to reduce the recall rate from screening.”
“Diagnostic accuracy seems to be increasing based on the information we’re seeing from early trials,” says ECRI’s Inamdar.
At the University of Colorado, where they went from one to all four of their units being 3-D, Hardesty shares similar views about the false negatives and positives. The technology pulls off a rare feat — while most technology updates either reduce false negatives or false positives, DBT goes a step further. “The main improvement for us is the ability to see false positives and increase actual detection,” Hardesty says.
Challenges still ahead
In addition to the heftier price tag, 3-D delivers some challenges for staff. “There’s definitely a learning curve,” says Hardesty. “However, my learning curve was less with tomo than it was with digital. We’re very comfortable with the appearance of mammo at this point. The larger issue is that we’re not looking at two images, we’re looking at hundreds. This means the reading time is on average about one and a half times longer,” she says.
Those additional images translate to a need for additional storage.
“Each of these exams is four-and-a-half gigabytes,” says Inamdar. “If you do 20 patients a day, in 10 days you have one terabyte of data to store. Cost can rise rapidly for a large mammography practice,” he says.
But hospitals and imaging centers may soon have a little more money to help pay for that storage. “The American Medical Association panel; accepted the application for CPT codes for tomo in May — three category one codes for diagnosis and treatment for tomo,” says Hologic’s Culley. “The coding will be published in November and the CPT codes and rates will be published in January of 2015.”
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