1. Radionuclide Imaging of Infection/inflamation
MUDr.Kateřina Táboská

2. Based on physiochemical processes in tissues
Accumulation in the lesion due to the locally changed physiological condition:
increased blood flow
enhanced vascular permeability
influx of white blood cells

3. AGENTS
Labeled Leukocytes
67Gallium –citrate
18FDG
99mTc MDP

4. Labeled Leukocytes Uptake of labeled leukocytes is dependent on
Intact chemotaxis
The number and types of cells labeled
total white count – 2x109/l , neutrophils
3) The cellular component of a particular inflammatory response : neutrophil – mediated inflammatory processes - bacterial infections

5. Labeled leukocytes In vitro: 111In – oxine
99mTc- HMPAO (hexamethylpropyleneamine oxime)
60ml of whole blood is withdrawn
Separation the WBC
Incubation with the radiolabel
Reinjection into the patient

6. Labeled leukocytes 2) In vivo:
99mTc murine monoclonal antibody against leukocyte cell membrane antigen
(Scintimun granulocyte)
Disadvantage: production of HAMA (human antimurine antibody)
alergic reaction
before repeated examination - titer

7. 99mTc- HMPAO WBC Indication: acute inflammatory conditions
Inflammatory bowel disease
infection of vascular or orthopedic prostheses

8. 111In WBC
111In, T1/2 67h, 174, 247 keV,
Indication: indolent conditions
Chronic infections
kidney infections

9. 99mTc- HMPAO WBC
111In WBC
Normal biodistrubion: liver, spleen, bone marrow, ( HMPAO genitourinary and gastrointestinal tracts )

10. 67Gallium –citrate Several factors govern uptake:
67Ga , T ½ 78 h, γ rays (93,184, 296, 338 keV)
Iron analog
Several factors govern uptake:
1) Bind to transferrin in the plasma
Increased blood flow and increased vascular membrane permeability result in increased delivery and accumulation in inflammatory foci
2) Bind to lactoferrin, which is present in high concetration in inflammatory foci
3) Bind to leukocytes
4) Direct uptake by bacteria - siderophore

11. 67Gallium –citrate Imaging: 18-72 h
Normal biodistribution: bone, bone marrow, liver, spleen, genitourinary and gastrointestinal tracts

12. 67Gallium –citrate Indication: Vertebral osteomyelitis
Immunocompromised patients
Opportunistic respiratory tract infections

13. 18FDG PET 18F, T ½ 110min, cyclotron produced glucose consumption
inflammatory cells have an increased expresion of glucose transporters when they are activated.
Cytokines and growth factors increase the affinity of glucose transporters for FDG.
Imaging:
1 h
Normal biodistrubion: , brain, liver, spleen, bone marrow

14. 18FDG PET
Indication:
fever of undetermined origin
vasculitis

15. IMAGING INDICATIONS Fever of Undetermined origin
At least 3-wk duration, several episodes of fever exceeding 38,3ºC and no diagnosis after an appropriate evaluation
% infection
% neoplasms
collagen vascular disease, granulomatous disease, cerebrovascular accidents

16. Fever of Undetermined origin
Duration of illness:
labeled leukocyte imaging is more sensitive early
High negative predictive value for labeled leukocyte imaging, negative study excludes focal infection as the source of FUO.
18FDG, 67Ga citrate later + imaging of tumor

17. Fever of Undetermined origin
18FDG
NHL
sarkoidosis

18. Opportunistic Infection
Do not incite a neutrophilic response
Affect lungs
67Ga citrate

19. Opportunistic Infection
67Ga citrate
diffuse uptake
Pneumocystis carinii pneumonia

20. Postoperative Infection
CT cannot always distinguish abscess from other fluid colection, tumor or normal postoperative changes
Labeled WBC
Labeled WBC accumulation through the left abdomen into the thigh – multiple abscesses were drained

21. Osteomyelitis 3F bone scintigraphy
3F bone scintigraphy + 67 Ga citrate
3F + WBC
WBC + bone marow imaging with sulfur colloid

22. Osteomyelitis
3-phase bone scintigraphy: 99mTc MDP
Bones not affected by underlying conditions
high specificity
Fractures, orthopedic hardware, neuropathic join - low specificity

23. 3-phase bone scintigraphy + 67Ga citrate
Osteomyelitis:
3-phase bone scintigraphy + 67Ga citrate
Improved the specificity: distribution is spatially congruent but the relative intensity of uptake of 67Ga citrate is greater than that of the bone agent
spinal OM : when MRI cannot be performed or is not diagnostic
99mTc MDP 67GA

24. Osteomyelitis:
Labeled leukocytes do not accumulate at sites of increased bone mineral turnover in the absence of infection
But inability to distinguish LL uptake from uptake in bone marrow
Labeled leukocyte + bone marrow imaging with 99m Tc –sulfur colloid

25. Labeled leukocyte + bone marrow imaging with 99m Tc –sulfur colloid
Both accumulate in the bone marow, only leukocytes accumulate in infection.
Painful prosthesis – infection, aseptic loosening
WBC bone marrow