Physiological Variations of FDG
Distribution and Pitfalls of
Interpretation of PET-CT
Dominique Delbeke, MD, PhD
Vanderbilt University Medical Center
Nashville, Tennessee
VUMC PET conference August 2009
Outline
FDG distribution
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Neck: glandular, lymphoid, muscular
Muscular system
GI
GU
GYN
Therapy-related changes
Inflammatory processes
PET technical artifacts
PET/CT technical artifacts
SNM PET/CT guidelines
„ Preparation of the patient
„ Reporting
Normal Distribution of FDG
Brain: high uptake in the gray matter
Myocardium: variable uptake
Lungs: low uptake
Mediastinum: low uptake
Liver: low uptake
GI tract: variable activity (esophagus,
stomach, colon)
Urinary tract: excretes FDG
Muscular system: low uptake at rest
Cook GJR, et al: Semin Nucl Med 1996;26:308-314
Physiological Variations of FDG Distribution
Neck:
„ Glandular tissue
„ Lymphoid tissue
„ Muscles
„ Brown fat
Laryngeal muscles:
vocalis and crico-arytenoid
Parotid glands
Oculomotor muscles
Oculomotor muscles
nasopharynx
Parotid glands
Tonsils
Sublingual gland
and myelohyoid
muscles
Submandibular
glands
Laryngeal
muscles
Patient with lymphoma in remission 6 months earlier
Uptake in
masseter muscles
due to chewing
Initial staging lung cancer
Uptake in R masseter and pterygoid
67 year-old female with medullary thyroid ca and rising calcitonin
Left vocal cord paralysis
16 year old female with lymphoma s/p therapy
Brown fat
Physiological Variations of FDG Distribution
FDG uptake in both
the thyroid gland
and laryngeal
muscles
Hashimoto Thyroiditis
From: Delbeke D et al (eds): “Practical FDG Imaging: A teaching File” Springer-Verlag 2002.
Physiological Variations of FDG Distribution
Muscular system:
„ Under tension or after exercise (e.g. chewing, talking,
swallowing, eye movement, hyperventilating, walking..)
„ Insulin endogenous or exogenous
Exercise
Endogenous insulin
51 year-old male with relapse Hodgkin’s lymphoma S/P chemotherapy
36 year-old man s/p lung transplant for hypersensitivity
pneumonitis, now lung nodules
other patient with lung cancer
Respiratory
insufficiency
28 year-old male with Hodgkin’s lymphoma and suspected recurrence
Nausea and vomiting
Weight lifting
22 year-old female with DLBCL s/p completion of therapy
Honeymoon effect
Physiological Variations of FDG Distribution: GI
GI tract:
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Lymphoid tissue
Smooth muscle activity
Stools
Metformin
Inflammatory disease…
Crohn’s disease
Lung cancer and colitis
From: Delbeke D et al (eds): “Practical FDG Imaging: A teaching File” Springer-Verlag 2002.
67 year-old female presents for initial staging of laryngeal cancer
Metformin
Gontier E et al. Eur J Nucl Med Mol Imaging 2008;35(1):95-99
Physiological Variations of FDG Distribution: GI
45-year-old man who
completed chemo and
radiation therapy for
SCC of the larynx
presents with
dysphagia
Esophagitis
65year-old female with
NSCLC referred for initial
staging
1) RUL NSCLC
2) Hepatic
metastases
3) Hiatal hernia
From: Delbeke D et al (eds): “Practical FDG Imaging: A teaching File” Springer-Verlag 2002.
Physiological Variations of FDG Distribution: GU
Patient evaluated for suspected
recurrent colorectal cancer
Right pelvic kidney
Renal transplant
55-year-old male s/p resection abdominal sarcoma 8 months
ago, presenting with suspicion of recurrence on CT
abdominal recurrent sarcoma and horseshoe kidney
Physiological Variation of FDG Distribution: GU/GYN
36 year old female with a 1 cm SPN
Horseshoe kidney and fibroids
Physiological Variation of FDG Distribution: GYN
33 year-old female just diagnosed with breast cancer
Uterus in a menstruating female
17 year-old female with HD in the neck and chest s/p completion of therapy
Ovaries benign
Lerman H et al. J Nucl Med 2004;45:266-271.
Physiological Variations of FDG Distribution: GYN
Dense breast
Lactating breasts
Vranjesevic D wet al. J Nucl Med 2003;44(8):1238-1242
Monitoring Response to Therapy with FDG PET:
Timing in Relation to Surgical Therapy
Surgery:
„ ~ 2 months for surgical site
„ Anytime for staging elsewhere.
58 year old man s/p mediastinoscopy
1 week earlier demonstrating NSCLC
62 year-old male s/p resection of recurrent lymphoma of
the small bowel 2 weeks earlier.
Diagnosis: postoperative changes
45 year-old female with anaplastic lymphoma S/P therapy
evaluated for bone marrow transplant
July 05
Bone marrow biopsy L iliac crest
Monitoring Response to Therapy with FDG PET:
Timing in Relation to Radiation Therapy
„ More than 6 months after completion of radiation:
Š FDG uptake indicates tumor recurrence
„ Early after radiation (within 2 months…up to…..):
Š FDG uptake matching the radiation port due to
inflammatory changes
„ Recommendations:
Š Wait as long as possible after radiation before performing
FDG PET
Š Comparison to baseline PET is helpful
Š Knowledge of radiation ports is helpful.
48 year-old man with HD diagnosed in 2003
48 year old man with lymphoma
diagnosed 1 year earlier and
treated with XRT to left axilla. He
recurred 2 months earlier and
was treated with chemotherapy.
57 year old male diagnosed with esophageal cancer in
July and treated with chemoradiation completed two
weeks before his follow-up PET scan
July 29
Oct 19
61 year-old female with T-cell lymphoma of left breast and mediastinum
s/p chemo and radiation
Radiation esophagitis
33 year-old male with DLBCL s/p chemo and radiation therapy to mediastinum
2 year earlier and referred for restaging
Radiation pneumonitis
81-year-old male with large
cell carcinoma treated with
radiation therapy
Radiation pneumonitis
From: Delbeke D et al (eds): “Practical FDG Imaging: A teaching File” Springer-Verlag 2002.
Monitoring Response to Therapy with FDG PET:
Timing in Relation to Chemotherapy
Physiological uptake in response to therapy
„ For 2-4 weeks: Bone marrow and spleen due to regenerating
bone marrow (hyperplasia)
Š Worse if bone marrow stimulating factors have been
administered with chemotherapy (e.g. G-CSF, neupogen)
„ Possible transient cellular stunning
„ Possible inflammatory response: metabolic flare
Recommendation:
„ At least 2 weeks after last chemotherapy or just before next
cycle
„ 2-months after completion of therapy
1 day post G-CSF
A 42-year-old
female who
underwent a left
mastectomy for
breast carcinoma
followed by
chemotherapy
presented with
rising tumor
2 weeks later
markers
Diagnosis: Severe bone
marrow uptake related to
administration of G-CSF the
day before
Thymic hyperplasia
Benign Diseases that Can Mimick Malignancy
Granulomatous lesions: e.g. tuberculosis, fungi,
sarcoidosis….
Other inflammatory processes
Hyperplasia/dysplasia
42-year-old male after completion of therapy for SCC of the
oropharynx
Sarcoidosis
From: Delbeke D et al (eds): “Practical FDG Imaging: A teaching File” Springer-Verlag 2002.
55 year old female with recurrent melanoma
1) Recurrent
melanoma in left
axilla
2) Vaccine injection
in right axilla and
bilateral groins
76 year-old male with pulmonary nodule
Pericarditis
76 year-old male with pulmonary nodule
Recent laminectomy
72-year-old female with weight
loss, fatigue, fevers and chills and
a lesion in the caudate lobe of
the liver on CT
Diagnosis: Surgery: Acute
gangrenous and hemorrhagic
cholecystitis with abscess
formation extending in the right
colon
Suspicion of Klatskin
Acute pancreatitis
43 year old s/p thyroidectomy for papillary thyroid cancer
presenting with borderline elevation of Tg, has Tg Ab and a
negative I-131 scan at time of previous recurrence.
Bx: granulomatous disease
Nocardia abscess
A 80 year-old male with a history of amyloidosis presented
for evaluation of SPN
Amyloidosis
64-year-old
male with
recurrent
left neck
lymphoma
post-stem
cell
transplant
From Vitola JV and Delbeke D. Nuclear Cardiology & Correlative Imaging, Springer-Verlag, 2004
60 year old male with NSCLC 2 years earlier presenting with
SVC syndrome
Thrombus in SVC
68-year-old male with mantle cell lymphoma with multiple LN in
the neck and abdomen
Diagnosis:
1) False – low grade lymphoma
2) Fem-Fem graft
PET Technical Artifacts
Malfunctioning detector
Injection site
Indwelling catheter
Sentinel lymph node visualization
57-year-old male with a history of lung cancer believed to
be in remission and referred for follow-up
Diagnosis: Malfunctioning detector
34-year-old female presents with persistent lympadenopathy in the
porta hepatis after completion of therapy for lymphoma
Diagnosis: FDG injection in port and visualization of indwelling catheter
From: Delbeke D et al (eds): “Practical FDG Imaging: A teaching File” Springer-Verlag 2002.
A 65-year-old male with a history of prostate cancer was
referred for evaluation of a pulmonary nodule.
Arterial injection
60 year old male with multiple
relapse of lymphoma, now new
1 cm mediastinal LN
Dose infiltration and FDG
uptake in sentinel LN
Artifacts on CT-attenuated PET images
Inaccurate co-registration due to: Random motion
„ less likely with short transmission scan
Artifacts on CT-attenuated PET images
Inaccurate co-registration due to: Respiratory motion
Š Inaccurate localization of lesion in the region of diaphragm
(dome of liver versus lung bases) in 2% of patients
Š Curvilinear cold artifacts along diaphragm
65 year-old with lung
cancer s/p XRT to
mediastinum 1 week
earlier
Radiation esophagitis
Goerres GW et al. Radiology 2003;226:906-910.
Osman MM et al. Eur J Nucl Med 2003;30:603-606.
Osman MM et al. J Nucl Med 2003;44:240-243.
Artifacts on CT-attenuated PET images
Hot spots due to over-correction related to:
„ IV contrast
„ Focal accumulation of oral contrast
„ Metallic implants (dental, hardware…)
Overestimation of SUV values by up to 10% compared to Ge68 based attenuation correction.
Antoch G et al.J Nucl Med 2002;43:1339-1342. No correction
Cohade C et al. J Nucl Med 2003;44:412-416.
Goerres GW et al. Eur J Nucl Med Molec Imag 2002;29:367-370.
Nakamoto Y et al. J Nucl Med 2002;43:1137-1143.
Antoch G et al. J Nucl Med 2004: 45 (Suppl): 56S.
standard
Thank you!
Brazil 2004