Clinical utility of 99mTc-labeled ubiquicidin 29-41 antimicrobial peptide for the scintigraphic detection of mediastinitis after cardiac surgery.
BACKGROUND
Previous studies demonstrated that (99m)Tc-labeled-ubiquicidin 29-41 ((99m)Tc-UBI 29-41) imaging is an accurate method for detection of bacterial infections. This study was conducted to evaluate the clinical use of (99m)Tc-UBI 29-41 for detection of mediastinitis after cardiac surgery.


METHODS
Thirteen patients with suspected mediastinitis after cardiac surgery were included. Qualitative and semiquantitative analyses of (99m)Tc-UBI 29-41 images were performed. Mediastinitis was confirmed by bacterial culture.


RESULTS
Qualitative analysis correctly identified the infection in 5/6 patients with mediastinitis. For observer 1, there were five true-positive results, six true-negative results, one false-positive result and one false-negative result (sensitivity: 83%, specificity: 85%, positive predictive value: 83%, negative predictive value: 85%, and overall diagnostic accuracy: 84%). For observer 2, there were five true-positive results, five true-negative results, two false-positive results and one false-negative result (sensitivity: 83%, specificity: 71%, positive predictive value: 71%, negative predictive value: 83%, and overall diagnostic accuracy: 76%). Agreement between observers was 0.847 (SE=0.145, p=0.002). Semiquantitative analysis showed a higher mediastinum uptake of the (99m)Tc-UBI 29-41 in patients with mediastinitis than that derived from patients without mediastinitis. Mean uptake of (99m)Tc-UBI 29-41 was 60.4+/-10.3 counts/pixel and 47.4+/-5.5 counts/pixel, respectively (p=0.01). At the threshold value of > or =57 counts/pixel using ROC analysis, the sensitivity, specificity, positive predictive value, negative predictive value and overall diagnostic accuracy for detecting patients with mediastinitis were 83, 100, 100, 87, and 92%, respectively (p=0.02; 95% CI: 0.65-1.10%).


CONCLUSIONS
(99m)Tc-UBI 29-41 imaging yielded fast and promising first results for patients with suspected mediastinitis after cardiac surgery and, as such, deserves further investigation.
Vallejo
Enrique
E
Instituto Nacional de Cardiologia Ignacio Chavez, Mexico, D.F., Mexico.
Martinez
Irma
I
Tejero
Alberto
A
Hernandez
Salvador
S
Jimenez
Luis
L
Bialostozky
David
D
Sanchez
Gustavo
G
Ilarraza
Hermes
H
Ferro-Flores
Guillermina
G
D000328:Adult; D000368:Aged; D000890:Anti-Infective Agents / Q000737:chemistry; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry; D005260:Female; D006801:Humans; D008297:Male; D008480:Mediastinitis / Q000175:diagnosis / Q000209:etiology; D008875:Middle Aged; D015609:Organotechnetium Compounds / Q000737:chemistry; D010446:Peptide Fragments / Q000737:chemistry; D011183:Postoperative Complications; D013903:Thoracic Surgery
D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; D015609:Organotechnetium Compounds; D010446:Peptide Fragments; C485080:technetium 99m ubiquicidin(29-41)