Imaging assessment FDG-avid lymphomas. Is Diagnostic CT a necessary adjunct to PET-CT?

Sami, M., Joshi, K., Raman, V., Burkill, G., Miles, K. A. and Dizdarevic, S. (2010) Imaging assessment FDG-avid lymphomas. Is Diagnostic CT a necessary adjunct to PET-CT? In: Annual Congress of the EANM, 2010, Vienna, Austria.

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Aim: Despite recent local introduction of evidence‐based guidelines recommending PET‐CT (low dose unenhanced CT) for staging and assessment of treatment response of predictably FDG‐avid lymphoma sub‐types, in our institution diagnostic CT with intravenous contrast enhancement is still often used in addition to PET‐CT at the same time in the course of disease. This study evaluates whether diagnostic CT yields additional diagnostic information for lymphoma patients when performed at same time as PET‐CT. Materials & Methods: We carried out a retrospective review of all lymphoma patients referred to our centre for PET‐CT imaging over a six month period (February 2008 ‐ July 2008). We determined whether these patients had undergone diagnostic CT at the same time. PET‐CT images were classified into ‘staging’ scans and ‘post-treatment’ scans and PET‐CT reports were compared with those of diagnostic CT to determine whether there were any differences in diagnostic yield between the two scans. Results: For the 98 PET‐CT examinations identified, diagnostic CT had been carried out at the same time in 47 (48%). 22 of these examination pairs (PET‐CT vs. diagnostic CT) were for staging, whilst 25 were post‐treatment. For staging, there was no difference in diagnostic yield in 10/22 (45%), other than one (5%) incidental finding on PET‐CT (uterine fibroids). PET‐CT upstaged diagnostic CT in 10/22 (45%) cases and increased confidence in reporting splenic disease on 1/22 occasion (5%). Diagnostic CT upstaged PET‐CT on no single occasion. Post‐treatment, there was no difference in diagnostic yield in14/25 cases (56%) other than 3 (12%) incidental findings on CT (initial SVC compression, uterine fibroids and interstitial fibrosis). In 4/25 (16%) cases PET revealed evidence of active lymphoma missed by CT whereas; in a further 3/25 (12%) cases PET confirmed no active disease in diagnostic CT residual masses. In one case (4%) of peripheral T‐cell Non Hodgkin’s Lymphoma, diagnostic CT demonstrated a possible new non‐FDG avid intra‐thoracic site of disease which was also seen on the CT component of the PET‐CT. No incidental finding (8%) was considered likely to impact on lymphoma management. Conclusion: Our results support the view that FDG‐PET‐CT obviates the need for additional diagnostic CT in FDG‐avid lymphoma. Diagnostic CT may have a remaining role in assessment of lymphoma sub‐types that are not predictably FDG avid.

Item Type: Conference or Workshop Item (Paper)
Additional Information: Conference: 23rd Annual Congress of the European-Association-of-Nuclear-Medicine (EANM) Location: Vienna, AUSTRIA Date: OCT 09-13, 2010 Sponsor(s): European Assoc Nuclear Med
Keywords: Radiology, Nuclear Medicine & Medical Imaging
Schools and Departments: Brighton and Sussex Medical School > Clinical and Experimental Medicine
Subjects: R Medicine > R Medicine (General) > R895 Medical physics. Medical radiology. Nuclear medicine
Depositing User: Patricia Butler
Date Deposited: 13 Mar 2012 11:26
Last Modified: 05 Oct 2017 18:26
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