Neuroimaging of tuberculosis- modalities, imaging protocols and radiomics: a review

Abstract

Background and Objective: A large number of review and research articles exists in literature which describe the radiological appearance of various manifestations of nervous system tuberculosis, however there is paucity of text which describes the application of each and every imaging modality in the workup of the entire spectrum of this pathology. The intent of this article is to review the existing literature on the role of different radiological modalities in the stepwise work up of CNS TB. The article focuses on the role of plain radiograph, fluoroscopy, computed tomography, magnetic resonance imaging along with its advanced sequences and nuclear medicine in imaging of the many faces of tuberculosis in CNS. The article also aims to review the existing literature on the role of MR based textural analysis (Radiomics) as a problem-solving tool in various nervous system pathologies. Methods: We searched PubMed central databases for articles published in English from January 1 2000 to February 28 2021 along with references from the relevant articles. The search terms included “imaging in central nervous system tuberculosis” “Radiomics in tuberculosis “, “Radomics in central nervous system ”. In total 95 articles including case reports, case series, original articles and review articles were included in this review. Results: Conventional imaging modalities including radiograph and fluoroscopy are becoming extinct in work up of tuberculosis in the nervous system itself, however a plain radiograph still holds a key position in screening the chest for presence of subclinical respiratory tract infection in patients presenting with brain tuberculosis. In addition, it is a sensitive tool as baseline investigation in workup of spinal tuberculosis (T.B). Fluoroscopy is a useful tool in image guided procedures for collection of samples for histopathology and CSF analysis. Cross sectional imaging modalities including computed tomography and magnetic resonance imaging have revolutionized imaging of central nervous system pathologies in particular tuberculosis. Computed tomography acts as a screening tool to identify the presence of intracranial tuberculosis and recognize its complications. In addition it is an important tool to determine the extent of spinal T.B. Magnetic Resonance Imaging (MRI) along with its advanced sequences including spectroscopy, Magnetization transfer T1 sequence (MT T1), perfusion imaging, and magnetic resonance angiography (MRA) and magnetic resonance venography (MRV) is an ideal imaging method to work up CNS TB. It can identify numerous manifestations of tuberculosis in the brain, work up its associated complication, and explain the extent of neurological symptoms. Moreover, it has the capability to differentiate TB from other nervous system infections. Furthermore, it can differentiate neoplastic and inflammatory brain disorders from CNS TB. Radiomics, particularly the textural features based on MR imaging is the future of neuroimaging. Its role is getting established in the work up of several intracranial pathologies including brain tumors and neurodegenerative disorders. Certainly, it has significant potential in the imaging work up of CNS tuberculosis, which is underexplored and therefore requires the central attention of upcoming researchers focusing on this topic.  Conclusion: Cross sectional imaging is the mainstay of imaging workup. Nuclear imaging is becoming an essential adjuvant to determine the burden of the disease. Role of radiomics is evolving in intracranial pathologies and certainly needs the central attention of future researches to establish its role in CNS TB imaging.