ECR 2019 / C-0358
FDG-avid nasty surprise: PET-CT detection of unsuspected M1 disease and its mimics in Scottish lung cancer patients
Keywords:
Metastases, Education and training, Cancer, Molecular imaging, Education, PET-CT, CT, Oncology, Hybrid Imaging
Authors:
L. Hartley, S. HAN; GLASGOW/UK
DOI:
10.26044/ecr2019/C-0358
Results
- 74% of cases were biopsy-proven NSCLC,
15% SCLC and 11% unknown.
49% of patients had prior CT chest and abdomen,
31% CT chest,
abdomen and pelvis and 20% CT chest. PET-CT was performed mean 26 days following the initial CT.
- 8% (197/2631) patients had FDG-avid distant metastases (F51: M49%; mean age 68 years).
Of these patients,
66% (130/197) had unsuspected M1 disease not identified on their initial CT at single (70%) or multi-sites (30%).
- A striking 81% of PET-positive bone metastases were undetected on previous CT; 73% of these bone lesions were CT-occult,
17% outwith FOV and 10% progressive disease.
M1 DISEASE SUBTYPE |
INCIDENCE OF FDG-AVID METASTASES ON PET-CT |
% OF THESE METASTASES UNDETECTED ON PRIOR CT |
BONE |
64% (126/197) |
81% |
ADRENALS |
29% (58/197) |
34% |
LIVER |
16% (31/197) |
67% |
LUNG |
9% (17/197) |
29% |
SOFT TISSUE |
7% (13/197) |
85% |
DISTANT NODES |
6% (11/197) |
64% |
PERITONEAL |
5% (9/197) |
22% |
PANCREATIC |
4% (7/197) |
71% |
BRAIN |
4% (7/197) |
100% (no neuroimaging) |
- 41 FDG-avid false positive lesions were identified following further imaging or biopsy to confirm or refute isolated distant metastases: 41% adrenal (9 x normal MRI,
6 x adenoma,
1 x pheochromocytoma),
24% bone (5 x normal MRI,
2 x haemangioma,
1 x red marrow focus,
1 x insufficiency fracture),
and 22% liver (6 x normal MRI,
2 x normal ultrasound,
1 x granuloma).
Additional metastatic mimics included pigmented villonodular synovitis,
gallbladder adenomyomatosis and mesenteric panniculitis.