18FDG-PET is sensitive tool for detection of extracranial tuberculous foci in central nervous system tuberculosis - Preliminary observations from a tertiary care center in northern India.

PURPOSE: To study the role of 18FDG- PET (Flourodeoxyglucose positron emission tomography) in a) determining the extent of cranial and extra-cranial disease and b) diagnosis as well as prognosis of CNS TB (central nervous system tuberculosis) including TBM (tuberculous meningitis). PATIENTS AND METHODS: This prospective observational study (n = 70) was carried out at a tertiary care institute in Northern India from 1.1.2017 to 30.6.2018. Diagnosis of TBM was made according to modified Ahuja's criteria. All patients were evaluated in detail and treated as per standard guidelines. All patients underwent 18FDG-PET scanning of brain and whole body at baseline. RESULTS: Mean age was 35.2 ±â€¯14.8 years. There were 37 men. Majority of patients (n = 47; 67.1%) were below 40 years of age. 43 (61.4%) patients were in stage II TBM. The mean duration of illness was 77 ±â€¯101.9 days. Majority of patients presented with fever (94.3%), headache (90%) and vomiting (84.3%). MRI was abnormal at baseline in 67 (95.7%) of patients, most common abnormalities being meningeal enhancement (68.6%) and tuberculomas (57.1%). PET was abnormal in 66 (95.7%) of patients. All these patients had either lung lesions (n = 62, 88.6%) or lymphadenopathy (n = 61; 87.1%). 18FDG-PET revealed evidence of brain lesions in 52 (74.3%) patients. It revealed vertebral involvement in 19 (27.1%) and genitourinary lesions in 9 (12.9%) patients. PET evidence of lymphadenopathy correlated significantly (p = .04) with good outcome in CNS TB. Conclusion 18FDG-PET does seem to have a promising role in initial evaluation of patients with CNS TB.