Susumu Tachinaga BSC, RT, Presenter: Nothing to Disclose

Ikuo Kawashita, Abstract Co-Author: Nothing to Disclose

Yasuhiko Okura PhD, Abstract Co-Author: Nothing to Disclose

Yuji Akiyama, Abstract Co-Author: Nothing to Disclose

Takashi Furukawa RT, Abstract Co-Author: Nothing to Disclose

Takayuki Ishida PhD, Abstract Co-Author: Nothing to Disclose

To develop an automated computerized method for detection and volume measurement of followed-up metastatic brain tumors in contrast enhanced 3D T1-weighted MR images.

Image database, consisting of 15 MR volume images of 6 individuals, included 88 metastatic brain tumors diagnosed as the metastatic brain tumors. The MR images with a 512 × 512 matrix in-plane and 1.5 - 2 mm slice thickness were obtained before and after radiotherapy and chemotherapeutic treatment for the metastatic brain tumors. The MR images were converted to the volume data with an isotropic resolution of 0.94 mm by use of a tri-linear interpolation. For the registration of current and previous MR image data sets, we applied the affine transformation to the current images. Then, tumor search area of previous image was determined by using brain segmentation technique with Otsu’s thresholding and Euclidean distance transformation. To enhance brain tumors in the extracted search area, a 3D cross-correlation with a 3D Gaussian template of 1 - 4 sigma was used. In addition, we eliminated false positives by using a feature analysis to determine metastatic brain tumors. The tumors before and after treatment homologized in coordinate system, and evaluated the difference of the tumors volume before and after treatment.

Our method was tested with a dataset 15 MR volume images including metastatic brain tumor. As the result, the sensitivity of final candidates was 97.4 % with 6.2 false positives per case. The matching rate of detected tumors was 100 % and achieved to evaluate the difference of the tumors volume before and after treatment.

The automated detection rate of metastatic brain tumors from contrast enhanced 3D T1-weighted MR images was 97.4 % of tumors, and this method allowed us to match and identify tumors before and after treatment.

Our method is useful to support following-up procedure of the metastatic brain tumors.

Tachinaga, S, Kawashita, I, Okura, Y, Akiyama, Y, Furukawa, T, Ishida, T, Development of Computer-aided Follow-up System for Metastatic Brain Tumors in Contrast-enhanced 3D MR Images.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9010173.html