Shabbir Hashimbhai Ezuddin MD, Presenter: Nothing to Disclose

Franco Giovanni Policaro MD, Abstract Co-Author: Nothing to Disclose

Donald Topping Weed MD, Abstract Co-Author: Nothing to Disclose

Mike F Georgiou PhD, Abstract Co-Author: Nothing to Disclose

George N Sfakianakis MD, Abstract Co-Author: Nothing to Disclose

Aldo Nicola Serafini MD, Abstract Co-Author: Nothing to Disclose

Tracey Jerona Lightbourn, Abstract Co-Author: Nothing to Disclose

Marie S Chery, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

Somatostatin receptors are found in high density in the cells of neuroendocrine organs and in some non-endocrine cells. The 24/4 hour ratios can help differentiate paragangliomas from other non-paragangliomas. Also it is valuable in the post treatment evaluation for residual tumor or recurrence in patients with equivocal CT/MRI imaging.

The study included 15 consecutive patients, 14 females and 1 male, ages 23-75 years (mean 45) between 2002 - 2003. Only biopsy proven cases were included. All patients had whole body planar imaging and SPECT acquisition of the head and neck at both 4 and 24 hours post administration of 6 mCi of 111In Octreotide. All SPECT images were acquired using a medium energy collimator using 64x64x16 matrix, 40 sec per stop for 64 stops. Region of interest (ROI) were placed around the tumor in multiple (3-5) transaxial SPECT slices and the maximum counts per pixel (MCP) was recorded. The ratio of 24/4 hour maximum counts corrected for the decay was then calculated. Images were interpreted separately by two board certified Nuclear Medicine physicians and Radiologists.

This review included 15 somatostatin avid masses in the head & neck region of which 11 were paragangliomas, 2 schwannomas and 2 branchial cleft cysts. Evaluation included 11 pre-treatment and 4 post-treatment cases. In pre-treatment evaluation, 4/11 cases were non-paragangliomas with equivocal CT/MRI scans and 24/4 hour ratio was between 0.16 - 0.6, 7/11 were paragangliomas, 5 had a ratio between 0.9 - 5.66 with 2/5 equivocal CT scans and 2 patients had glomus typanicum (GT) which showed characteristic CT findings and their ratios were 0.4. In post treatment evaluation, 4/4 patients the ratios ranged between 0.28 to 1.03 and 2/4 had equivocal CT/MRI findings.

In pre-treatment evaluation of the head and neck, 24/4 hour ratios were invaluable in identifying non-paragangliomas from paragangliomas. GT paragangliomas have characteristic CT findings therefore even a low ratio should be considered diagnostic. In the post-treatment category, where CT/MRI findings are not specific, the ratios are variable, hence any uptake should be considered as indicative of residual tumor or recurrence.

M.F.G.,A.N.S.: CO-INVESTIGATOR FOR MALLINCKRODT SPONSERED INSTITUTIONAL CLINICAL TRIAL(Protocol No 0050-02-763) F.G.P.: CO-INVESTIGATOR FOR MALLINCKRODT SPONSERED INSTITUTIONAL CLINICAL TRIAL(Protocol No 0050-02-763)S.H.E.: PRINCIPAL INVESTIGATOR FOR MALLINCKRODT SPONSERED INSTITUTIONAL CLINICAL TRIAL(Protocol No 0050-02-763)

Ezuddin, S, Policaro, F, Weed, D, Georgiou, M, Sfakianakis, G, Serafini, A, Lightbourn, T, Chery, M, et al, , Ratio of Quantitative Analysis of Four and Twenty Four Hour Indium111-labeled Octreotide SPECT Images Can Have a Significant Impact in the Initial Diagnosis and Post-Therapy Managemetn of Paragangliomas of Head and Neck.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4407634.html