Krishnamoorthy Thamburaj MD, Presenter: Nothing to Disclose

Arvind Choudhary MBBS, Abstract Co-Author: Stockholder, General Electric Company Stockholder, Pfizer Inc

To assess the ADC values of different regions of pediatric brain tumors and establish an ADC threshold for diagnosis.

A retrospective analysis of 26 cases of pediatric brain tumors were analysed for ADC values. All the cases have undergone conventional MR imaging with echoplanar diffusion sequence performed in axial plane. In all cases the histopathological examination was established after surgery. The slice for ADC measurement was selected based on consensus after excluding cystic areas, necrosis, hemorrhage and calcification. Totally 6 ADC measurements were obtained from a tumor using circular region of interests. The first measurement included the entire tumor in a single ROI. Subsequently the tumor was divided into 4 quadrants and ADC was obtained from each quadrant as well as from the center of the tumor. The size of the ROI for measuring quadrants and center of the tumor was kept constant for all cases.

There were 14 males and 12 females. The lowest ADC value for astrocytoma was 1.006 x 10-3 mm2/S and the highest 1.806 x 10-3 mm2/S. The lowest for ependymoma 0.961 x 10-3 mm2/S and highest was 1.372 x 10-3 mm2/S. The lowest for medulloblastoma was 0.535 x 10-3 mm2/S and the highest was 1.032 x 10-3 mm2/S. We could not establish a cut off for astrocytomas as they were showing wide variation.

A cut off value of less than 0.9 x 10-3 mm2/S will be helpful to diagnose medulloblastomas. A cut off value of more than 0.9 x 10-3 mm2/S and less than 1.3 x 10-3 mm2/S will be helpful to diagnose ependymomas. Sampling more tumor areas and averaging them is more likely to be helpful to distinguish ependymomas and medualloblastomas. We need study on large number of patient population to confirm our findings and to see whether we could establish a cut off value for astrocytomas, CPP, epidermoid and meningioma and other pediatric brain tumors.

To help in the diagnosis and management of brain tumor in children using ADC values.  

Thamburaj, K, Choudhary, A, ADC Threshold in Pediatric Brain Tumors: Can We Have a Cut Off Value?.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6021379.html