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Radionuclide imaging in patients with fever
Otto Lang MDDept Nucl Med
3rd School of MedicineCharles University
Prague
materials for medical students
Fever
• Non-specific reaction of the body (T>38oC)
• Most frequent cause inflammation (tumors)
• Inflammation – Infective and non-infective
• Usually fever with other signs of imflammation
• Clinical picture very important
• Other laboratory tests including imaging methods (NM, sono, CT, MRI) are essential
Fever • Probable etiology should be taken into account
– Fever in patient post surgery
– Fever in patient with renal failure
– Fever in patient with HIV positivity
– Fever in patient with septicaemia
– Fever of unknown origin• Fever for 3 weeks with unknown origin despite 1 week intensive hospital
evaluation
– Fever in children
– Fever in soft tissue inflammation
– Fever in bone infection
– Fever in patient with abdominal sepsis
– Fever in patient with different tumors
Fever • Radiopharmaceuticals
– organ specific – show damage of appropriate organ (defect of functioning tissue)
• Tc-99m diphosphonates – bone scan
• Tc-99m DMSA - kidneys
– organ non-specific – accumulates directly in inflammed tissue (little bit tumors, wounds, hematomas)
• Ga-67 citrate – infective, non-infective, tumors
• labeled leukocytes – pyogenic infection
• Tc-99m IgG – non-infective
• F-18 FDG
Ga-67 - properties• Used in a form of citrate• Binds to plasmatic proteins, excretion by
kidneys (24 h) and then intestinal mucosa• Degree of accumulation correlates with
process activity• Basic principles of accumulation:
– Complexes with plasma transferrin– Binds to intracellular lactoferrin inside leukocytes– Can binds directly to some parts of bacteria
• Patient preparation:– Laxatives - fast elimination from the bowel
Ga-67 - procedure
• Injection of 150-180 MBq – high energy, long half-life, high absorbed
dose, worse spatial resolution (image qual)
• Acquisition 4-6 h p.i., then from 24 h to 3-4 days
• Collimator for medium energy
• Whole-body study, spot view (larger frame matrix), SPECT
Ga-67 – clinical significance
• High sensitivity (90%) but low specificity –
used as a locating agent – it locates site of damage so other more specific methods can be used
• More suitable for chronic inflammation
• Not very good for abdominal inflammation evaluation due to physiological excretion via intestinal mucosa
Ga-67 – clinical indications
• Specific inflammation (sarcoidosis, tuberculosis)
• Imunocompromised patients (lung inf)
• Thoracic inflammation (fibrosis, vasculitis)
• Non-infective inflam – process activity (kollagenosis)
• Fever of unknown origin– wide spectrum of possible causes
• Osteomyelitis
• Abdominal and retroperitoneal inflamation (pyelonefritis, absces)
Labeled leucocytesproperties
• Basic pinciples of accumulation– positive chemotaxis (no injury during
labeling process)– also healing wounds and tumors
• Labeling process– in vitro - separation, laboured– in vivo - monoclonal antibodies
• Patient preparation– fasted (blood processing)
Labeled leucocytes procedure
• Labeling – 60 ml venous blood (kids min. 12 ml) – separation, washing up, labeling – cca 1.5 h– Labeling with Tc-99m HMPAO (300 – 500 MBq)
or In-111 oxin (20-40 MBq)
• Data acquisition – 30 min, 4-6, 24 (48 In) h post injection– Whole-body study, spot view (larger frame
matrix), SPECT
Labeled leucocytes clinical indication
• Unspecific bowel disease (Crohn, UC)
• Diabetic foot syndroma
• Musculosceletal infection
• Fever of unknown origin (within 2-3 w)
• Imunocompromised patients
• Joint prosthesis infection
• Acute arthritis
• Vascular prosthesis infection
Tc-99m IgG
• Non-specific polyclonal
• Labeled with In-111 or Tc-99m.
• Accumulates predominantly within interstitial space
• Physiological accumulation – blood-pool, liver, spleen, kindeys, bone marrow and nasal mucosa
• Main indication
– Revmatic (non-infective) inflamation
F-18 FDG• Metabolic analog of glucose
– enter cells but no metabolism – accumulates according to degree of metabolic turnover
• Imaging by PET
• Metabolically active processes (inflam, tumors) - more glucose than other tissue
• Mainly used as a locating agent (like Ga-67) and mark of activity
• PET – much better spatial resolution (better image quality)
New ways
• Imaging of bacteria– labeled chemotherapeuticals (chinolony)
• dependent on antibiotics therapy
• Chemotactic peptides– interleukin 2 – non-infective inflammation
(autoimmune)
• Combined methods– Streptavidin (tissue senzibilization) and then
labeled biotin
Ga-67 citrate
physiological distribution
male and female
Ga-67 - sarkoidosis
Ga-67 – sarkoidosispanda-sign
Ga-67 – sarkoidosispanda and delta sign
Ga-67 – lung fibrosis
Ga-67 - tuberculosis
Ga-67 - urosepticaemia
Ga-67 – thyroiditiscomparison with Tc-99m pertechnetate
Labeled leucocytes
physiological distribution
Labeled leucocytes ulcerative colitis
Labeled leucocytes ulcerative colitis or Crohn´s disease?
Labeled leucocytes ulcerative colitis
Labeled leucocytes infection of hip prosthesis
Diabetic foot syndroma
Patient JU 1961, X-ray chron. OM
Patient JU 1961, bone scan posit.
Patient JU 1961, leu scan negative
F-18 FDGphysiological distribution
FUO
Fever of unknown origin(all methods failed)PET revealed:- aortitis/vasculitisAs a bonus:- Breast cancer(vasculitis as a paraneoplastic sign)
Vascular prosthesis infection PET FDG
Joint prosthesis infectionPET FDG