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Updated: Feb 23, 2026
Analysis of 18FDG PET/CT Imaging as a Tool for Studying Mycobacterium tuberculosis Infection and Treatment in Non-human Primates
Published on: September 5, 2017
A comparison of 18F-FDG PET/MR with PET/CT in pulmonary tuberculosis
Benjamin A Thomas1, James S Molton, Francesca Leek
1aAgency for Science Technology and Research, National University of Singapore Clinical Imaging Research Centre bDepartment of Medicine, Yong Loo Lin School of Medicine, National University of Singapore cUniversity Medicine Cluster, National University Health System, Singapore dInstitute of Nuclear Medicine, University College London, London, UK.
Purpose:
PET/computed tomography (CT) has been shown to detect lesions in patients with pulmonary tuberculosis (PTB) and may be useful for assessing PTB disease in clinical research studies. However, radiation dose is of concern for clinical research in individuals with an underlying curable disease. This study aimed to determine whether PET/MR is equivalent to PET/CT in PTB.
Materials And Methods:
Ten patients with microbiologically confirmed PTB were recruited. Patients received 129.0±4.1 MBq of fluorine-18-fluorodeoxyglucose. Five of the 10 patients underwent a PET/MR scan, followed by PET/CT. The remaining five were first imaged on the PET/CT, followed by the PET/MRI. PET acquisition began at 66.7±14.4 min (mean±SD) after injection when performing PET/MR first (PET/CT: 117.2±5.6 min) and 92.4±7.6 min when patients were imaged on PET/MR second (PET/CT: 61.1±3.9 min). PET data were reconstructed iteratively with Ordinary-Poisson Ordered-Subset Expectation-Maximization and reconstruction parameters were matched across the two scanners. A visual lesion detection task and a standardized uptake value (SUV) analysis were carried out. The CT Hounsfield unit values of PTB lesions were also compared with MR-based attenuation correction mu-map tissue classes.
Results:
A total of 108 PTB lesions were detected on PET/MR and 112 on PET/CT. SUV analysis was carried out on 50 of these lesions that were observed with both modalities. Mean standardized uptake value (SUVmean) and maximum standardized uptake value (SUVmax) were significantly lower on PET/MR (SUVmean: 2.6±1.4; SUVmax: 4.3±2.5) than PET/CT (SUVmean: 3.5±1.5; SUVmax: 5.3±2.4).
Conclusion:
PET/MR visual performance was shown to be comparable to PET/CT in terms of the number of PTB lesions detected. SUVs were significantly lower on PET/MR. Dixon-based attenuation correction underestimates the linear attenuation coefficient of PTB lesions, resulting in lower SUVs compared with PET/CT. However, the use of PET/MR to measure the response of lung lesions to assess response to treatment in research studies is unlikely to be affected by these differences in quantification.
Insights
Positron emission tomography/magnetic resonance (PET/MR) imaging detects a comparable number of pulmonary tuberculosis (PTB) lesions as PET/computed tomography (CT). While standardized uptake values (SUVs) are lower with PET/MR, this difference is unlikely to impact research assessments of treatment response.
Area of Science:
- Nuclear Medicine
- Radiology
- Infectious Disease Research
Background:
- Positron emission tomography/computed tomography (PET/CT) is used to detect lesions in pulmonary tuberculosis (PTB).
- Concerns regarding radiation dose in clinical research for curable diseases like PTB exist.
- PET/MR imaging offers a potential alternative with reduced radiation exposure.
Purpose of the Study:
- To determine the equivalence of PET/MR imaging compared to PET/CT for detecting PTB lesions.
- To evaluate the quantitative differences in standardized uptake values (SUVs) between PET/MR and PET/CT in PTB patients.
Main Methods:
- Ten patients with confirmed PTB underwent both PET/MR and PET/CT imaging after receiving fluorine-18-fluorodeoxyglucose.
- Imaging sequences were performed in a crossover design (PET/MR then PET/CT, or vice versa).
- Lesion detection rates and standardized uptake values (SUVs) were compared between modalities; CT Hounsfield units were correlated with MR-based attenuation correction.
Main Results:
- A total of 108 PTB lesions were detected by PET/MR and 112 by PET/CT.
- Mean and maximum SUVs were significantly lower on PET/MR compared to PET/CT.
- Dixon-based attenuation correction in PET/MR underestimated the linear attenuation coefficient of PTB lesions.
Conclusions:
- PET/MR demonstrates comparable visual performance to PET/CT in detecting PTB lesions.
- Lower SUVs on PET/MR are attributed to attenuation correction methods but are unlikely to affect research assessments of treatment response.
- PET/MR is a viable alternative to PET/CT for PTB research, offering reduced radiation exposure.
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