In this study the accuracy of MRI was similar to CT in describing findings related to culture-positive patients [12]. Inferential data regarding the value of MRI can also be derived from its role in cystic fibrosis and the observation in other settings that MRI correlates well with CT for parenchymal findings including bronchiectasis, cavitation, and tree- in-bud nodules [13]. Although MRI is technically feasible and described in the literature, MRI has not been specifically evaluated as a primary imaging modality for patients with suspected or proven TB. Nuclear scintigraphy Several nuclear radiopharmaceuticals have been employed for the purpose of evaluating possible TB, particularly for differentiating active from inactive tuberculomas and distinguishing tuberculomas from neoplasms. In small studies, Tc-99m methoxyisobutylisonitrile has shown higher activity over background in active tuberculomas compared with inactive tuberculomas [14,15]. Similarly, metabolic activity measured by fluorine-18-2-fluoro-2- deoxy-D-glucose positron emission tomography (FDG-PET) is higher in active tuberculomas. Dual-time-point FDG-PET imaging (1 and 2 hours postinjection) can also help differentiate active tuberculomas from neoplasms, owing to the longer retention of FDG in benign lesions [16]. Gallium 67 has been used to follow patients for disease activity and correlates with the number of organisms on sputum smears [17]. Evidence for the use of nuclear imaging to diagnose active TB is limited to either small single-site studies or several small studies, and the impact on clinical practice and patient care at this time is minimal. Discussion of the Imaging Modalities by Variant Variant 1: Suspect active tuberculosis. The initial suspicion of active TB should be made based on clinical symptoms and demographics.
Imaging of Possible Tuberculosis. In this study the accuracy of MRI was similar to CT in describing findings related to culture-positive patients [12]. Inferential data regarding the value of MRI can also be derived from its role in cystic fibrosis and the observation in other settings that MRI correlates well with CT for parenchymal findings including bronchiectasis, cavitation, and tree- in-bud nodules [13]. Although MRI is technically feasible and described in the literature, MRI has not been specifically evaluated as a primary imaging modality for patients with suspected or proven TB. Nuclear scintigraphy Several nuclear radiopharmaceuticals have been employed for the purpose of evaluating possible TB, particularly for differentiating active from inactive tuberculomas and distinguishing tuberculomas from neoplasms. In small studies, Tc-99m methoxyisobutylisonitrile has shown higher activity over background in active tuberculomas compared with inactive tuberculomas [14,15]. Similarly, metabolic activity measured by fluorine-18-2-fluoro-2- deoxy-D-glucose positron emission tomography (FDG-PET) is higher in active tuberculomas. Dual-time-point FDG-PET imaging (1 and 2 hours postinjection) can also help differentiate active tuberculomas from neoplasms, owing to the longer retention of FDG in benign lesions [16]. Gallium 67 has been used to follow patients for disease activity and correlates with the number of organisms on sputum smears [17]. Evidence for the use of nuclear imaging to diagnose active TB is limited to either small single-site studies or several small studies, and the impact on clinical practice and patient care at this time is minimal. Discussion of the Imaging Modalities by Variant Variant 1: Suspect active tuberculosis. The initial suspicion of active TB should be made based on clinical symptoms and demographics.