 Now what is the role of high-resolution CT scan? You have patient who has dyspnea, who has dry cough, X-ray just looks normal. So this patient is symptomatic. Then whether you do HRCT because you want to see whether there is ILD or there is an ILD. Now is there an ILD? Characterize the ILD. Find out whether it is reversible or irreversible. If it is confusing then you have to tell how to do hypoxia. Whether it is trans-brompial or open lung biopsy. And last but not the least to follow up the treatment especially if NSIP. Steroid given and it is resolving or if it is IPF it is drastically increasing because the survival rate is very poor in an IPF. Without knowing the history a chronic history HP and an IPF and a chronic sarcoid will all look the same. You have to also if possible get a previous CT if possible if the patient has. Now let's start. All of you know that interstitial pneumonia is 7 types where they start it. Though they are pneumonia they are not infected. This was the initial 7 types that recently they were described into DIP, AIP, NSIP, RP-ILD, Cryptogenic Organizing Pneumonia, LIP plus there is UIP in it. What has happened is now they are separated into smoking related and non-smoking related. So RP-ILD is a smoking related. Now again I am saying interstitial pulmonary fibrosis we do tend to give this diagnosis but this is pathology or dystopathological diagnosis. What we are describing is a UIP pattern. Now when it comes to IPF, UIP is IPF but UIP pattern is not IPF. Got it? Now what I am describing here is there in your books is IPF. Commoner in males more than usually 50 or more than that. Progressive dyspnea and pulmonary hypertension. You have to remember how does it look? So what about the patterns are there? They are usually basal that is lower lobes, sub plural predominant. So there is an apipope basal. Consistent finding of septal thickening, honey combing, traction bronchiectasis and bronchielectasis. Ground class opacity is less common. It is commoner with NSIP. But again I told you when you know this is the case of IPF that is it has all the signs of irreversibility and it or she gets some ground class opacity. That means there is a exact reservation and there is an acute alveolitis in a chronic case. So this is inter and intra-lobular septal thickening. As of now there is subtle bronchiectasis, bronchielectasia. What happens is as the bronchiectasis go peripheral they converge, the walls converge. You have no business of seeing such big bronchiectasis in the peripheral. So this is traction bronchiectasis. As of now there is no honey combing for patient but there is no ground class also. Now say patient the basal segments is showing honey combing. The moment you get honey combing that means this is irreversible. In cases of IPF there are certain things that you should keep in mind. Lymph nodes can occur, fuses can rupture forming either a small loculated pneumothoracist or even the mediastinal honey combing can rupture and form a small pockets of pneumo-mediastinal. There are certain IPFs which within 2 months can really deteriorate. So few pointers you have to keep in mind. So you have to look if there is additional esophageal dilatation in this case. Then your IPF diagnosis is wrong. Your UIP pattern diagnosis should come not UIP, UIP pattern. Then you can say that this UIP pattern is related to maybe sclerolerma because the esophagus is dilated. Now this is a full blown chronic irreversible UIP pattern but male patient more than 50 years. So safely can call it IPF provided you also have a little clinical backup. You have bilateral basal honey combing. You have honey combing between architectural distortion mainly in the lower lobes. So this is a typical chronic stage of IPF. Now let's go to this case. What do you have here? Is this honey combing? Yes. Is this apico basal radial? Yes. Because there is more in the bases than in the apices. There is traction rocket bases. There are these cysts formation but there are no three layers. But here there are three layers. So again this is architectural distortion in bilateral lower lobes to a lesser extent in the upper lobes. But when it comes to UIP there are these probable, typical or non-consistent in UIP. So this is a very important newer thing that has come and lot of chess decision know about it. And they will ask you is this probable, is it typical or non-consistent. Let's go on to the case. What do you have here? You have apices, honey combing, internavular septal thickening and there is loss of architecture especially in upper lobes. So what will you call this as? Is there basal environment? Not much. So this is a UIP pattern or typical pattern. See this? This is a corner image showing you bilateral honey combing in upper lobes. There are changes in the lower lobes but much less. So this is an or typical UIP pattern. Again showing you the lateral fill of right and left lump. So any guesses? This is an or typical UIP pattern. So you do not call this IPF. You call it UIP, or typical. Why? Or typical? Because it's not involving the bases. So this was a stage 4 sad point.