A study carried out by researchers from Brigham and Women’s Hospital and Massachusetts General Hospital (MGH) came to the conclusion that diffusion-tensor MR tractography could be used as an imaging biomarker for evaluating the efficacy of prostate cancer treatment. The results were presented at the American Roentgen Ray Society (ARRS) meeting in Toronto.
The study included two groups of 11 patients. All 22 of them had proven prostate carcinoma (elevated prostate antigens and biopsy). The first group was treated with androgen deprivation, radiation therapy or a combination of both methods, while the second group received no treatment and served as the control. The scientists discovered that using quantitative measurements with MR tractography they were able to see higher tract densities in the first group which is an indicator of prostate shrinking and lessening of fibrosis.
Using available software, Diffusion Toolkit and TrackVis (МGH), researchers were able to generate 3D fiber tracts from the diffusionweighted images. They chose 3D regions of interest (ROIs) over cancerous areas and healthy parenchyma in both groups. The values for number of tracts and density were recorded and later shown as a standardized measure of the number of tracts in the ROI.
The results showed a significant difference between the two groups. Group 1’s average tract density in the tumorous region was 2.25 and 3.34 in normal parenchyma. The control group’s numbers were 1.64 and 2.74, respectively.
"Diffusion tensor MR tractography may function as a novel quantitative tool and marker of treatment response," said study coauthor Jennifer W. Uyeda, MD, Brigham and Women's Hospital. "For example, absence of rise in tract density after therapy and persistent or wider gradient can signify poor response."
This new method for evaluating treatment response has shown a significant difference in tract density between study and control group. Improving methods for identifying efficacy of treatment is necessary and inevitable, because choosing treatment based solely on subjective opinion is incorrect. MR tractography gives healthcare professionals the tools to see how each individual is responding, an invaluable resource of information.