 Now, what pattern is this? This is a different pattern. You have septal thickening and some plural rim of maybe 2-millimetre sparing, more of ground glass. So, intra-lobular septal thickening, no honey combing, no traction bronchitis. What do you think this is? NSIP. NSIP, perfect. Non-specific interstitial pneumonia. And this was positive Anka. So, now we know this is NSIP and this was positive. So, some kind of a connective tissue disorder and the pattern in that connective tissue disorder just finding it NSIP like. So, what is NSIP? 80% have ground glass opacities, lack of honey combing. We just discussed there was no honey combing, there is no traction bronchitis and a differential diagnosis of NSIP because NSIP alone can be just, the histopathology can be NSIP only or it can be NSIP pattern. So, NSIP pattern can be seen in mixed collageal muscular disorder. What I told you, a good HRCT, is this a good HRCT? No, because there is a lot of non-compliance when it came to breath hold because this patient has dyspnea. So, a lot of haziness is seen even there is no sharpness to the findings that you are seeing of the ground glass opacities. When you report, if you don't get honey combing but you are getting sub-fluorous pairing of ground glass opacities and you get a little type of bronchiolitis or bronchiolactasia with ground glass but no honey combing then you can safely call this fibro-otic pattern of NSIP. So, you have a cellular pattern, the first case that I showed you was a cellular NSIP. Like this is a cellular but you can have some amount of dilated bronchiol. This could be a fibro-otic NSIP. So, you have two types. Now, another case, multiple nodules seen in bilateral lung. Now, these nodules are of ground glass density. Is there honey combing? No. Is there ground glass a little bit? Is there traction bronchitis? No. Is there interstitial septal thickening? No. So, what is your diagnosis? Do you think it is a subacute HV? Yes, hypersensitivity pneumonitis. Now, not many a times you image a acute HV. Most of the time you image subacute HV which you saw. These are centilometer nodules scattered in bilateral lobes and most of them are more in the upper lobes but they are also similar lobes and you have a positive history. So, you need history. Here you don't need the pathologist because you are not going to do a lung biopsy but you need for bar, bronchoscopy with lavage. You need the pathologist. That is why it is a multidisciplinary. And chronic HV as I told you goes into fibrosis and the findings are similar to what you get in UIP pattern. The only thing in HV that you should remember is look if there are any areas of mosaic attenuation. You have a UIP pattern and you have black areas that is black and white. That means there is some amount of air trapping. Usually air trapping and UIP pattern points towards chronic HV. safely you can say that. I am not talking about this as I told you you need the pathologist for this. So, there is no escape of the three doctors that you need. So, multiple cases and this is increasing because of pigeon exposure in rainy season because of fungus in the small rooms that people are saying. So, all these are exposure towards allergens. So, these if you can appreciate these are small ground glass density nodules scattered in bilateral lung without any traction bronchial cases or honey coping. At least there are no lymph nodes. So, this is most likely suggestive of subacute HV but you need of course your pathologist or the microbiologist for serology. Now, this is what I meant. If in a case where they are going to go to Crawl City you see something like this black area that means there are areas of air trapping which is commonly seen with HV and this is the time where you need to do extreme treatment. So, that if this is attenuated that means that it is exaggeration of the black area or exaggeration of mosaic pattern that means there is air trapping. Again, so a full quality HV more upper lobe. So, this is more ground glass and multiple nodules. It is a difficult diagnosis to call it as a subacute HV but the clinicians will definitely help or you can give a positive challenge test. If you know the patient is staying near a area where the pigeons are fed or there is dampness can take out the patient from that surrounding that is what the clinician is going to do. If you raise a possibility of a subacute HV this is what the clinician is going to do. Now, chronic HV as I told you is similar to this. What is this? UIV pattern. Now, again another pattern what you have here you want to call it MSIP right but this is not MSIP. So, these are multiple consolidation of nodes with septic thickness and rahulacic and this is in a correct setting. You should think when you have consolidations which are peripheral, not particularly in a particular lobe, more triangular, subclueral, think of cryptogenic organising pneumonia initially called as bronchiolitis optic trans organising pneumonia. Again, peripheral, whatever I have said is going to come you can have mediasodial lymph adenopathy again here. You can have brutal effusion like in this case there can be some amount of fever but dry cough in a given clinical setting, triangular base multiple consolidations with septal thickening again a consolidation. So, multiple consolidation not defined to one lobe. Think of card.