MicroCT Aiding Diagnostics for Breast Cancer – A Preliminary Study
A very interesting study published in the Journal of BMC Cancer by a collaboration of universities and hospitals in Belgium has used microCT to acquire 3D reconstructions of microcalcifications in breast tissue. Using the Bruker Skyscan in-vivo 1076 scanner, researchers scanned 11 breast biopsies ranging from women aged 46 to 78 years whose 2D mammograms revealed indications of calcification. Sizes of the biopsy were approximately 3mm diameter by 23mm length. The biopsy samples were immersed in a tube containing formalin and scanned in the 1076 at a pixel size of 35 microns and an energy of 60kV. Short scan times of 24 minutes were obtaining by selecting a rotation step of 0.5 degrees over 180 degree scan with an exposure time of 1800ms per step.
The 11 samples were then reconstructed with NRecon and then analyzed using CTAn. The analysis process involved segmenting the microcalcification from the soft tissue background and then performing 3D morphometric analysis, including volume, surface, thickness, and structural model index (SMI).
The results showed that almost half of patients (5 of 11) had ductal breast carcinoma (in-situ). The use of the microCT determined statistical size differences in the microcalcifications between patients with malignant or benign findings. Specifically, benign calcifications had a larger size than their malignant counterparts. This has a strong clinical implication because mammography is typically done with a projection radiography technique, meaning a 2D image of a 3D object. Based on the larger size, clinicians could have a greater confidence in interpreting a larger sized calcification as benign versus malignant. Mammographs also typically underestimate the number of calcifications because of their 2D nature, though according to the authors, there have been no significant correlations between malignancy and number of calcification in literature.
Despite its small scope, this study by Willekens et al. has laid out some very promising groundwork for a larger clinical study in the future which could assess more layers of information of calcifications such as their characterization level as benign or malignant. It would also be interesting to see this work continued on an ex-vivo MicroCT system which allows for considerably higher resolution.
To read the full publication, find it here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3893600/