Parul Mohan MBBS, MD, Presenter: Nothing to Disclose

Harsh Mahajan MD, MBBS, Abstract Co-Author: Nothing to Disclose

Ravi Kashyap MD, Abstract Co-Author: Nothing to Disclose

This prospective study was undertaken to perform a comparative analysis of Tc-99mGHA ,Tc-99m MIBI, MRI and MRS to correctly monitor therapy response in patients presenting with CNS tumors

This study was undertaken in a group of 57 post-op cases of brain tumors. Brain SPECTwas acquired at 30 minutes and 2 hours, using a Dual headed SPECTafter injecting 20 mCi Tc-99m GHA and 20 mCi Tc-99m MIBI intravenously on two separate sittings. MR examination was performed on a 1.5 tesla MR system. The analysis of SPECT and MR data was performed by independent double-blinded observers.

Data Interpretation was done by reconstructing the views for quantitative evaluation and calculating functional index ratio (tumor uptake/background uptake ratio. MIBI index was correlated with tumour recurrence as proved by histology and/or rapid, fatal evolution of these cases. A value of 3.0  was considered significant for active mitotic pathology. A similar ratio was calculated with GHA as GHA index, which was significant at a value of 4.5. Image quality suffered in Tc-99m MIBI scans due to secretion of Tc-99m MIBI by the choroids plexus. Good correlation of Brain SPECT was found with both MRI and MRS.Tc-99m GHA gave a sensitivity of 97.5%, specificity of 81.2% and an accuracy of 92.9%. Tc-99m MIBI gave a sensitivity of 95.1%, specificity of 87.5% and an accuracy of 92.9%. MRI gave a sensitivity of 92.6%, specificity of 75%, and an accuracy of 87.7%. MRS gave a sensitivity of 95.1%, specificity of 75% and an accuracy of 89.4%.

This comparative analysis showed that MRS improves in image interpretation of MRI, however it requires a dedicated team and an appropriate imaging system. Tc-99m MIBI and Tc-99m GHA are useful in differentiating radionecrosis and recurrence of brain tumor. Tc-99m GHA is found to be as useful as Tc-99m MIBI. Therefore depending on the availability and expertise developed, any two modalities could be used for decision making.

Brain SPECT using GHA, which is cheaper and more cost-effective than MIBI, can be used to differentiate viable tumor from radionecrosis in post-operated cases of cerebral gliomas.

Mohan, P, Mahajan, H, Kashyap, R, Comparative Analysis of Brain SPECT Using Tc-99m GHA and Tc-99m MIBI with MRI and MRS in Cerebral Gliomas.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14045415.html