Usefulness of adding SPECT/CT to 99mTc-hexamethylpropylene amine oxime (HMPAO)-labeled leukocyte imaging for diagnosing prosthetic joint infections.

Abstract

OBJECTIVE:

This study evaluated the usefulness of adding single-photon emission computed tomography (SPECT)/computed tomography (CT) (SPECT/CT) to technetium Tc 99m (Tc) hexamethylpropylene amine oxime (HMPAO)-labeled leukocyte imaging for diagnosing infections in hip or knee joint prostheses.

METHODS:

The Tc-HMPAO-labeled leukocyte scans of 164 patients (71 with hip prostheses and 93 with knee prostheses) with clinically suspected prosthetic infections were reviewed retrospectively. Planar images were taken 4 to 6 and 21 to 26 hours after injecting the labeled leukocytes and SPECT/CT images were obtained 4 to 6 hours after the injection. The final diagnosis of infection was based on pathologic findings (n = 70), bacteriological data (n = 61), or clinical follow-up (n = 33).

RESULTS:

Of the 164 patients, 89 patients had a diagnosis of prosthetic joint infections. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy of the planar images alone were 82.0%, 88.0%, 89.0%, 80.5%, and 84.8%, respectively. When the planar images were combined with SPECT, the sensitivity, specificity, PPV, NPV, and diagnostic accuracy were 91.0%, 88.0%, 90.0%, 89.2%, and 89.6%, respectively. When the planar images were combined with SPECT/CT, these values increased further to 93.3%, 93.3%, 94.3%, 92.1%, and 93.3%, respectively. Adding CT to SPECT resulted in a greater increase in sensitivity and specificity for hip prosthesis infections than for knee prosthesis infections. SPECT/CT mainly contributed by precisely localizing the anatomical site of the active inflammatory lesion and by delineating the extent of the lesion after diagnosis with SPECT.

CONCLUSIONS:

Single-photon emission computed tomography/CT combined with Tc-HMPAO-labeled leukocyte imaging was useful for diagnosing prosthesis infections, particularly in hip prosthesis infections, as it improved diagnostic accuracy and provided anatomical localization data.

• Authors: Hye Ok Kim, Sae Jung Na, Seung Jun Oh, Bong Sung Jung, Soo-Ho Lee, Jae Suk Chang, Seong-Il Bin, Jin-Sook Ryu
• Journal: Journal of computer assisted tomography (J Comput Assist Tomogr) 2014 Mar-Apr Vol. 38 Issue 2 Pg. 313-9 ISSN: 1532-3145 [Electronic] United States
• PMID: 24625603 (Publication Type: Journal Article)

Chemical References

• Technetium Tc 99m Exametazime

Topics

• Adolescent
• Adult
• Aged
• Aged, 80 and over
• Female
• Hip Prosthesis
• Humans
• Knee Prosthesis
• Leukocytes (diagnostic imaging)
• Male
• Middle Aged
• Multimodal Imaging
• Predictive Value of Tests
• Prosthesis-Related Infections (diagnostic imaging)
• Retrospective Studies
• Sensitivity and Specificity
• Technetium Tc 99m Exametazime
• Tomography, Emission-Computed, Single-Photon
• Tomography, X-Ray Computed