A contrast-free MRI breast imaging technique combined with sophisticated data analysis could reliably differentiate malignant and benign breast lesions and reduce the number of unnecessary breast biopsies, according to a study from the German Cancer Research Center (Radiology 10.1148/radiol.2017170273).
Breast MRI is used to screen women at high risk of breast cancer and as an adjunct to mammography to clarify findings suspicious for cancer. The examination currently uses intravenously injected gadolinium-based contrast agents, which carry significant health risks for some patients.
Diffusion kurtosis imaging is an alternative approach that eliminates the need for contrast agents in some cases. The technique, which uses diffusion-weighted imaging (DWI) measurements derived from MRI, provides a picture of breast tissue on a microstructural level.
“Diffusion kurtosis imaging has been introduced in DWI to provide important information on tissue structures at a microscopic level,” said lead author Sebastian Bickelhaupt. “Since malignant lesions disrupt the tissue structures at this level, diffusion kurtosis might serve as a relevant marker of changes.”
Bickelhaupt, co-lead author Paul Jaeger and colleagues evaluated a retrospective analysis of data collected from 222 women at two independent study sites. The women had suspicious mammography findings that were classified as BI-RADS 4 (a suspicious abnormality) or BI-RADS 5 (highly suspicious of malignancy) lesions. All women underwent DWI, followed by biopsy.
The researchers developed a software algorithm for lesion characterization, and extracted imaging features using a kurtosis-based radiomics model. Radiomics analysis in an independent test set of 127 women reduced false-positive findings by 70%, while detecting 60 of 61 malignant lesions.
“The model might help to lower the number of BI-RADS 4 lesions suspected of being cancer on the basis of screening mammography while retaining a high sensitivity similar to the sensitivity reported for biopsies themselves,” Jaeger said.
Should the results hold in larger trials, the model has other potential clinical advantages. The algorithm makes the assessment reader-independent, ensuring that its accuracy is maintained across different imaging facilities. Bickelhaupt emphasized that the new approach is not intended to replace current contrast-enhanced breast MRI protocols in general, but to expand the spectrum of options available for answering specific clinical questions.