 CNS tuberculosis, which is probably the second most common infection in our country following 60 circumstances. So let's look at how tuberculosis plays out, the pathophysiology, typical versus atypical imaging findings, sick will and complications of CNS tuberculosis, and natural course of HILD and MDR TB. So like they say for tuberculosis anywhere else in the body, TB can affect anything and everything in this skull. It can be parenchymal, it can be pachymeninjel, it can be leptomeninjel, it can be intraventicular, subdural, extradural, and even it can involve the skull vault. The commonest of course is tubercular meningitis. It happens because of spread of bacillus by the process of bacillemia, typically coming from pulmonary tuberculosis. A small subpile or subappendable focus of infection gets lodged in the subcortical or periventricular white matter, and it is similar to Gon's focus in the chest and it's called as Reach's focus. As it grows if untreated, it ruptures and spreads along the subarginal spaces and CSF and causes leptomeninjitis. Typically in the early stage tubercular leptomeninjitis can look like any other meningitis. You'll have minimal hydrocephalus, extensive enhancement along the cerebral convexities and also along the basal systems. As it progresses or as it gets treated it gets localized to basal systems and typically you get thick exudates along the basal systems like in this child. It can also go and get lodged in ventricles and then can cause ventriculitis. This child had tuberculomas, basal meningitis and also ventriculitis and there's a giant tuberculoma here. Compared to meningitis, focal tuberculoma is less common and again it is secondary to an intractive focus somewhere else in the body, typically lungs. It may or may not be associated with meningitis. A typical tuberculoma is dark on T2 because it contains caseous material, it's slightly bright on T1 again because of caseous material being present and it can show thick ring enhancement like this or it can show tiny nodular enhancement like this. Some of them can be based against meninges. On spectroscopy you get a tall lipid peak with little bit of lactate and other metabolites get suppressed because this peak is very very tall. If you want to differentiate it from a cystic tumor like metastasis or glioblastoma, on spectro you just get lipid peak in tuberculoma and in cystic tumor you will get choline and may be a smaller lipid peak with destruction of NA. Most of the tuberculomas are hyperperfused on ASL and perfusion imaging. In post-hectal stage they can show little bit of hyperperfusion and the periphery. There are several other manifestations of CNS tuberculosis which you should be aware of. There is an entity called a giant tuberculoma, by definition these tuberculomas are more than 2.5 centimeters in diameter. As I said they are slightly bright on T1, dark on T2. Many times they show onion peel like appearance, ring within ring, show thick ring enhancement, don't show restricted diffusion, they are hyperperfused and show tall lipid peak. In children like you get miller tuberculosis in lung, you can get what is called as disseminated tuberculomas in the brain. They can be few hundred in number, they are rare, they are smaller in size compared to the standard tuberculomas. They can be bright on T2, many of them are hypo, they show round or nodial enhancement and respond very well to conventional AKT. Sometimes they can calcify and simulate starry night appearance of 60 circuses. So this is a 14 year old child had miller tuberculosis, got obtended, came into PSU and has at least 50-55 tuberculomas all over the place. The clincher here is leptomanager enhancement along right silver fissure. Bad untreated basal meningitis can have cerebritis as presentation because of involvement of the adjoining brain parenchyma by ischemia or infection itself and clinically they present like encephalitis or cerebritis, otherwise the looks are similar. In chronic stages some of the untreated or MDRXD at tuberculosis can cause vasculitis and then present with Moyamoya like phenomenon on MRNG.