1. FDG PET CT : "metabolic biopsy " revisited
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!
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Dr. C P Wong
Clinical PET Center, Hospital Authority
Nuclear Medicine Unit
Queen Elizabeth Hospital
Hong Kong
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9/11/2013
1

2. Eur J Nucl Med (2001, Sep) 28:1336–1340

3. 63 patients underwent FDG-PET scans for lung lesions!
!
either after unsuccessful biopsy or, in lesser number of cases,!
when an attempt at biopsy was considered too dangerous!
!
follow-up by histology or clinical progress to death or minimum of 18 months!
!
Visual analysis --- positive / negative predictive values - 90% and 100%,
respectively!
!
Quantitative (SUV2.5) analysis ---- positive / negative predictive values -!
90% and 85%, respectively

4. Eur J Nucl Med (2002 April) 29:542–546

5. FDG-PET scanning was performed in 50 patients!
!
most underwent unsuccessful biopsy of lesion outside the lung!
!
fewer with no attempt at biopsy as considered too dangerous!
!
follow-up by histology or clinical progress to death or minimum of 12 months !
!
visual and quantitative analysis was performed!
!
visual analysis --- positive / negative predictive values - 89% and 100%
respectively!
!
quantitative (SUV2.5) -- positive / negative predictive - 93% and 86%,
respectively!

6. !
“ FDG PET, with unique ability to differentiate benign
from malignant disease, may provide a “metabolic biopsy”
as an alternative to tissue biopsy and separate those
requiring further investigation from those who do not”

7. Metabolic Biopsy : implication in 2013

8. M1
Benign
M3
Malignant
M2
SUVmax. 2.5
M4

9. Illustrated Cases

10. M/77
!
Poorly differentiated adenoCa stomach
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Total gastrectomy in 1996
!
Had LUQ abdominal mass in 2010
!
CEA : 98
!
Contrast CT : splenic mass and
sacral lytic bone metastasis
!
!
8/2010

11. SUVmax. 11.2

12. SUVmax. 2.5

13. PET CT
Markedly hypermetabolic splenic mass suggesting malignancy.
!
Faintly hypermetabolic sacral lytic lesion. Owing to significant
different FDG uptake patterns, not suggesting secondary from
poorly differentiated Ca stomach and also different entity from
splenic mass.
!

14. Splenectomy : metastasis from Ca stomach
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Sacral lesion biopsy : chordoma

17. Diffuse large B cell lymphoma
F/80
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Back pain
!
MRI : sacral tumor
!
Private PET CT :
solitary malignant looking tumour
in sacral body with invasion into
the sacral canal and presacral
space.
!
Chordoma has to be considered.
!
Possibility of a metastatic lesion is
less likely since this is a solitary
lesion and no primary site of
malignant tumour is demonstrated.
!
Differential diagnosis also includes
Giant Cell Tumour.

19. SUVmax. 5.8
Clin Nucl Med 2008;33: 906–908

20. Chordoma :
!
•
rare malignant bone tumor (local erosion but low metastatic
potential)
!
•
arises from notochord remnants of neuraxis and vertebral
bodies
!
•
more common in males
!
•
rare in patients aged 40 years
!
•
most commonest sites : sacrum and skull base
!
!

21. M/ 77
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presented with fever incidental
finding of RML lung mass.
!
blood culture : Klebsiella and
Streptococcus anginosus. Completed
a course of antibiotics.
!
CT post antibiotics : 4.2cm RML
lung mass.
!
Biopsy : squamous cell carcinoma.
!
PET CT for staging.

26. PET CT :
Hypermetabolic right middle lobe CA lung. !
!
FDG avid RUL lung mass, suggesting intra-pulmonary metastasis.!
!
4.5cm non hypermetabolic left frontal lobe cerebral mass with mild
midline shift to right by the mass effect. No significant perilesional
edema seen. The FDG uptake pattern favors primary brain tumor.
Suggest MRI correlation.!
!
Hypermetabolic enlarged soft tissue mass medial to the left parotid
gland. This can be a Warthin 's tumor or ? secondary from Ca lung.
Suggest pathological correlation.

27. MRI :

28. Parotid gland pathology :

29. M/ 64
!
RUL squamous cell Ca lung
!
CT contrast before PET CT :
!
• 6.5cm RUL lung mass, likely malignant
neoplasm
!
• Lobulated mass at left renal sinus,
worrisome for neoplasm (in particular
renal metastasis in current context)
!
• Several sclerotic lesions at vertebrae, bone
secondaries cannot be excluded

30. PET CT for workup

37. PET CT :
!
Hypermetabolic necrotic Ca lung
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Non FDG avid left renal mass, not suggesting secondary
!
Hypermetabolic left parotid gland nodule, likely Warthin’s tumor
Non FDG avid sclerotic bone lesions, likely benign

38. Pathology
FNAC left parotid gland nodule confirmed Warthin ‘s tumor

39. M/73
!
Metastatic adenoCa lung, failed
chemotherapy
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Palliative RT to mediastinum

41. Pericardial fluid
cytology :
metastatic
adenoCa

42. F/ 78!
!
abdominal distension and on off
vaginal spotting x 1 year!
!
mild right sided abdominal pain!
!
P/E : pelvis mass ~ 10cm!
!
USG: large heterogenous pelvic
mass 16cm, right hydronephrosis !
!
CEA : 21.6; CA125 : normal!
!
No histological proof so far

45. PET CT :
Large multi septated cystic mass at pelvic cavity, which is not
associated with obvious FDG uptakes. These can be a tumor
mass arising from adnexa such as mucinous cystadenoma /
cystadenocarcinoma of ovary in current context of raised!
CEA.!
!
Non FDG avid cystic nodule at lower anterior midline
abdominal wall, this can be a Sister Mary Joseph's nodule
can be accessed for pathological correlation. !
!

46. Pathology (TAHBSO + debulking)

47. F/ 48, Mucinous Breast Cancer

48. M/54
!
Known CA lung and RUL lobectomy
!
Metastatic bilateral SCF and mediastinal
lymph nodes, treated with chemoRT
!
Then found raised CEA ~1yr. later
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56. Left cerebellar mass resected
!
Pathology : metastatic Ca of lung primary

57. Factors affecting FDG tumoral uptakes in PET CT
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•
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Histology subtypes
Histology grading
Differentiation / dedifferentiation, e.g. Thyroid Ca
Size
Non cellular components, e.g. necrosis, mucinous, fluid
space

58. “ Metabolic Biopsy “ has its strength and weakness…...

59. Clinical PET CT reporting
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• Pathology subtypes
• Treatment (chemotherapy, radiation therapy
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others)
Biochemical markers : tumor markers, LDH,
WBC, Serum protein
electrophoresis…...
Co-morbidity
FDG uptakes
Size
Morphology
Artifacts

60. Georges-Pierre Seurat

61. Thank you