Clinical feasibility of two-step streptavidin/111In-biotin scintigraphy in patients with suspected vertebral osteomyelitis.
OBJECTIVE
Streptavidin accumulates at sites of inflammation and infection as a result of increased capillary permeability. In addition to being utilised by bacteria for their own growth, biotin forms a stable, high-affinity non-covalent complex with avidin. The objective of this investigation was to determine the diagnostic performance of two-step streptavidin/111In-biotin imaging for evaluating patients with suspected vertebral osteomyelitis.


METHODS
We evaluated 55 consecutive patients with suspected vertebral osteomyelitis (34 women and 21 men aged 27-86 years), within 2 weeks after the onset of clinical symptoms. Thirty-two of the patients underwent magnetic resonance imaging (MRI) and 24, computed tomography (CT). DTPA-conjugated biotin was radiolabelled by incubating 500 microg of DTPA-biotin with 111 MBq of 111In-chloride. Two-step scintigraphy was performed by first infusing 3 mg streptavidin intravenously, followed 4 h later by 111In-biotin. Imaging was begun 60 min later.


RESULTS
Streptavidin/111In-biotin scintigraphy was positive in 32/34 patients with spinal infection (94.12% sensitivity). The study was negative in 19/21 patients without infection (95.24% specificity). The corresponding results for MRI and CT were 54.17% and 35.29% (sensitivity), and 75% and 57.14% (specificity), respectively. All statistical parameters of diagnostic performance (Youden's J index, kappa measure of agreement with correct classification, accuracy, sensitivity, specificity, positive likelihood and negative likelihood) were clearly better for streptavidin/111In-biotin scintigraphy than for either MRI or CT.


CONCLUSIONS
Streptavidin/111In-biotin scintigraphy is highly sensitive and specific for detecting vertebral osteomyelitis in the first 2 weeks after the onset of clinical symptoms, and is potentially very useful for guiding clinical decisions on instituting appropriate therapy.
Lazzeri
Elena
E
Regional Center of Nuclear Medicine, University of Pisa Medical School, Pisa, Italy.
Pauwels
Ernest K J
EK
Erba
Paola A
PA
Volterrani
Duccio
D
Manca
Mario
M
Bodei
Lisa
L
Trippi
Donatella
D
Bottoni
Antonio
A
Cristofani
Renza
R
Consoli
Vincenzo
V
Palestro
Christopher J
CJ
Mariani
Giuliano
G
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001710:Biotin / Q000031:analogs & derivatives*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010019:Osteomyelitis / Q000175:diagnosis / Q000000981:diagnostic imaging*; D004369:Pentetic Acid / Q000031:analogs & derivatives*; D011877:Radionuclide Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013131:Spine / Q000000981:diagnostic imaging*; D013166:Spondylitis / Q000175:diagnosis / Q000000981:diagnostic imaging*
C400052:DTPA-bis-biotin; D001710:Biotin; D004369:Pentetic Acid