CC BY 4.0 · World J Nucl Med 2023; 22(02): 152-170
DOI: 10.1055/s-0043-1769948
Presentation Abstracts

Can FDG PET/CT Be Used to Optimize the Treatment of Patients with Pulmonary Tuberculosis?

Aisha Ismaila
1   Department of Nuclear Medicine, University of Pretoria, Steve Biko Academic Hospital and Nuclear Medicine Research Infrastructure (NuMeRI), South Africa
,
Ismaheel Lawal
1   Department of Nuclear Medicine, University of Pretoria, Steve Biko Academic Hospital and Nuclear Medicine Research Infrastructure (NuMeRI), South Africa
2   Department of Radiology and Imaging Sciences, Emory University, Atlanta, Georgia, United States
,
Kgomotso Mokoala
1   Department of Nuclear Medicine, University of Pretoria, Steve Biko Academic Hospital and Nuclear Medicine Research Infrastructure (NuMeRI), South Africa
,
Chris Hikuam
3   South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease and Division of Immunology, Department of Pathology, University of Cape Town, South Africa
,
Matsonso Mathebula
4   Department of Medical Microbiology and MeCRU, Sefako Makgatho University of Medical Science, Pretoria, South Africa
,
Ingrid Moagi
4   Department of Medical Microbiology and MeCRU, Sefako Makgatho University of Medical Science, Pretoria, South Africa
,
Mike Sathekge
1   Department of Nuclear Medicine, University of Pretoria, Steve Biko Academic Hospital and Nuclear Medicine Research Infrastructure (NuMeRI), South Africa
› Author Affiliations
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    Introduction: The treatment of pulmonary tuberculosis is long due to the slow-growing nature of Mycobacterium tuberculosis (MTb). At the end of a standard course of antituberculous treatment (ATT), some patients still harbor slow-growing MTb (sgMTb) in their lesions, which are responsible for relapse. These sgMTb are nonculturable and are difficult to detect. We investigate the utility of end-of-treatment [18F]F-FDG PET/CT to differentiate patients with sterilizing cure versus those with sgMTb who are at risk for relapse.

    Methods: We prospectively recruited patients who had a standard course of ATT. All patients underwent [18F]F-FDG PET/CT within 2 weeks of completing ATT. We determined the presence of residual metabolic activity (RMA), which is FDG uptake in the lungs above mediastinal background activity on the [18F]F-FDG PET/CT. Patients were classified as having RMA or complete metabolic response (CMR) to ATT. All patients were subsequently followed up after completing [18F]F-FDG PET/CT imaging for relapse. Confirmatory bacteriologic testing was performed in patients with clinical suspicion of relapse. In those who relapsed, a repeat FDG PET/CT imaging was subsequently performed.

    Results: We studied 75 patients including 50 HIV-infected individuals with a mean age of 36.09 ± 10.49. The median CD4 count among HIV-infected patients was 255 cells/mm3 (IQR: 147– 448). HIV viral load was 12,497 copies/mL (IQR: 158–3,8841). HIV-infected patients had lower hemoglobin levels (13.07 ± 1.78 g/dL vs. 14.24 ± 2.07, p = 0.021) and higher C-reactive protein levels (5.70 vs. 1.20, p = 0.001) compared with HIV-uninfected patients. All other baseline clinical and demographic characteristics were not significantly different between the groups. Forty-one patients had RMA and its incidence was not significantly different between HIV-infected and uninfected patients (p = 0.101). Thirty-four patients demonstrated complete metabolic response (CMR) to ATT. No tuberculosis relapse was demonstrated in those with CMR. In the RMA group, three patients (7.3%) relapsed on follow-up. Relapse was confirmed bacteriologically in all the three patients. Repeat [18F]F-FDG PET/CT imaging at the time of clinical relapse demonstrated the persistence of RMA in the same lung regions in all three patients.

    Conclusion: FDG PET/CT imaging demonstrates a high prevalence of RMA among patients treated with a standard course of ATT for PTB, with a similar incidence between HIV-infected and uninfected patients. CMR on posttreatment [18F]F-FDG PET/CT is consistent with sterilizing a cure for pulmonary tuberculosis. Patients with RMA on posttreatment [18F]F-FDG PET/CT are at risk for tuberculosis relapse. These results show the potential of [18F]F-FDG PET/CT for use as a noninvasive biomarker for drug development and in investigating shorter ATT regimens.


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    No conflict of interest has been declared by the author(s).

    Publication History

    Article published online:
    25 May 2023

    © 2023. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/)

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