[Music] this is the 8th video in this series on interpreting chest x-rays and the topic is focal lung disease today's learning objectives are to be able to identify localize and describe focal opacities particularly pneumonia and to know the varied appearances of pulmonary nodules and cavitations and their differential diagnosis I'll start by discussing lobar anatomy and radiographic zones in the chest in order for us to accurately describe location of a focal lesion some of this was originally covered in the second video on normal chest x-ray anatomy but to very quickly review the horizontal fissure of the right lung is typically the only fissure that may be visible on the PA view being roughly horizontal at the level of the hilum it's generally not visible on the lateral view the oblique fissures are located here but because they run at oblique angles to the x-ray beams in both the PA and lateral views they are usually not visible in either the right upper lobe is located here and the right middle lobe most notably making a wedge shape as seen from the side and the right lower lobe which not only comprises the most inferior portion of the lung but most of the posterior surface as well frequently extending up as high as the aortic arch and then the left upper lobe which anatomically would probably be better described as the left anterior lobe and the left lower lobe which would be better described as the left posterior lobe while it's very helpful to identify the location of focal lesions by the specific lobe in which they have appeared to be located clinicians frequently interpret aap films without the benefit of a lateral as you may imagine it is often not possible to identify the exact lobe when only given one view therefore when only given the front to back view whether it's a P or P a one can describe location based on lung zones there are four anything at the level of the clavicle or above is in the apical zone the upper zone extends from the clavicle down to the superior aspect of the hilum mid zone includes anything at the level of the hilum and the last the lower zone is anything below the hilum be aware that these lungs owns do not correlate with the lung zones numbered one two and three that are discussed within the context of pulmonary physiology mechanical ventilation and PA catheter placements these zones are a completely different concept so let me now talk about some focal opacities the first thing to discuss is the distinction between the confusing terms opacity infiltrate and consolidation there are no formal definitions for these terms and they are often used interchangeably and in nonspecific ways in the most common usage at least in the US the term consolidation is reserved for a relatively large dense homogenous opacification frequently involving an entire lobe some radiologists recommend against using the term infiltrate altogether as it strongly biases other clinicians to assume the etiology is an infection if the term infiltrate is used it is helpful to qualitatively describe it as alveolar interstitial nodular or cavitary when identifying and localizing and opacity there are two helpful radiographic signs the first is called the silhouette sign which there is a loss of the normally visible border of an intra thoracic structure caused by an adjacent pulmonary density for example a density in the right upper lobe can obscure the border of the ascending aorta a right middle lobe opacity can obscure the right heart border the right lower lobe obscures the right diaphragm left upper lobe can obscure either the aortic knob and/or the left heart border which is specifically bordered by the portion of the left upper lobe called a lingula and a left lower lobe opacity can obscure the left diaphragm and/or the descending aorta take a look at this example which normal border is obscured by a density and therefore where is that density located in this case it's the left heart border that's obscured and therefore the opacity is located in the lingula another helpful radiographic sign is often called the spine sign this refers to the presence of an abnormal increase in a pacification overlying the spine while moving superior to inferior on the lateral view suggestive of lower lobe opacities for example consider these two lateral films on the normal film on the left as one moves superior to inferior along the spine there is a progressive increase in lucency such as the vertebral body just above the diaphragm is the darkest in the film on the right there's an increase in the pacification as one reaches the inferior most to vertebral bodies just above the diaphragm suggestive of a lower lobe opacity it is not possible to tell from the lateral film alone whether the surpass ''tis in the right lower or left the lower lobe what are some of the ideologies of focal opacities obviously there are infections that is pneumonia which can be bacterial viral fungal or micro bacterial there are malignancies which can be primary lung cancer metastatic disease or lymphoma and other ideologies include pulmonary infarction pulmonary hemorrhage vasculitis and eosinophils pneumonia let me focus on infectious pneumonia for a few minutes as this is by far the most common etiology of focal opacities there are several distinctive radiographic patterns of pneumonia for example the best well-known and easiest to identify is lobar pneumonia this is characterized by homogenous consolidation air Branko grams and sharp borders which correspond to fissures the classic concept of organism of this subtype is streptococcus pneumoniae also known as pneumococcus contrasting with lobar pneumonia is segmental pneumonia more frequently referred to as bronchopneumonia bronchopneumonia consists of patchy opacification and vague borders it is frequently bilateral and air Branca Graham's are relatively uncommon classic positive organisms include staph aureus and Pseudomonas Klebsiella and H flu are commonly associated with both types then there is interstitial pneumonia in which the pacification has reticular pattern lacking air Branca Graham's interstitial pneumonia often develops into airspace disease mimicking the appearance of bronchopneumonia typical organisms to cause interstitial pneumonia are micro plasma viruses and Pneumocystis round pneumonia has an interesting spherical shape which is easily mistaken for a tumor or other lung mass it is much more common in children than adults and is caused by H flu and streptococcus finally cavity pneumonia which we'll come back to later in the video may or may not have air fluid levels and is classically seen in TB and snap aureus so let's apply some of this information to understand and interpret some x-rays of pneumonia what do you see here There is obviously a pacification in the right mid and lower lung zones there are peers to be a silhouette sign and such that the right heart border is obscured suggesting that your pacification is located in the right middle lobe we can also easily see the sharp demarcation between the opacity and normal lung tissue this border corresponds to the horizontal and right oblique fissures there's an air Bronco gram right here and notice that the right costophrenic sulcus is clear suggesting that the right lower lobe is not affected by the pathologic process so how would you summarize this chest x-ray this is a right middle lobe lobar pneumonia most likely result of streptococcus pneumonia but also possibly Klebsiella or homoplasy influenza how about this x-ray there's a silhouette sign in which the left diaphragm is obscured on the lateral film there is a pacification of the lower thoracic vertebrae also known as the spine sign and therefore this is a left lower lobe lobar pneumonia in this example we see your pacification in both lower lung zones you pacification czar not as sharply defined as in the last two films and there are no obvious air Bronco grams this is bronchopneumonia here are two examples of the unusual round pneumonia it's easy to appreciate why they can be mistaken for a lung mass they can't be distinguished radio graphically from these but rather on the clinical history and the fact that the round ammonium will resolve over days to weeks let's move on to discuss pulmonary nodules the entity of a solitary pulmonary nodule is defined as he well circumscribed generally round density smaller than 3 centimeters in diameter if it's larger than 3 centimeters it's referred to as a lung mass the differential diagnosis and general approach is largely the same although nodules are one of the most important findings which radiologists look for when evaluating an x-ray majority of there may be missed on initial review a comparison to prior x-rays is critical when evaluating for them the differential diagnosis for a solitary nodule is very long it includes various forms of cancer the most common of which is primary lung adenocarcinoma most cases of metastatic cancer present as multiple pulmonary nodules infectious and inflammatory causes include granulomas which are typically very small well demarcated and calcified there are consequences of prior infections such as histoplasmosis coccidioidomycosis and tuberculosis granulomas are generally believed to be responsible for the majority of benign nodules which I've never personally understood since the infections which are classically described as leading to them are themselves relatively uncommon in this country as we just saw with round ammonia these can present with an identical appearance and there are some congenital ideologies such as an arterial venous malformation and a bronchogenic cyst an important aspect of successfully identifying a pulmonary nodule is using the correct amount of contrast consider these two films they are identical with the exception of increased contrast in the film on the right side I think most people will concur that the nodule is slightly easier to see when the contrast is turned up a bit and consider this example where is the nodule here although it's approximately the same size and round shape as the film on the right its central location near the hilum makes it much more difficult to spot when patients present with multiple pulmonary nodules the differential diagnosis changes quite a bit one should still worry about cancer however there are now a number of other infectious ideologies to consider these include fungal pneumonia micro bacterial pneumonia nocardia septic emboli parasites specifically a kind of caucus Paragon de myiasis and schistosomiasis rheumatoid arthritis and vasculitis finally one miscellaneous cause of multiple pulmonary nodules is amyloidosis here are just a couple of examples of patients presenting with multiple pulmonary nodules here is metastatic disease in this case this is from endometrial cancer and invasive Aspergillus and here are some rarer causes amyloidosis on the left and a kind of caucus on the right in the right film that specific morphology of the nodules in which they are unusually large very circular and have overlapping appearances are sometimes called cannonball nodules most pulmonary emboli result in no apparent changes on chest x-ray rarely a large PE can result in one of several eponymous findings first is the unfortunately named Hamptons hump this is a wedge or dome-shaped plural based epatha T due to lung infarction this opacity may take months to resolve and frequently leaves scarring in that region sometimes Hamptons hump can be a little bit more subtle then there is Westermarck sign which is focal Oleg emia which is a fancy way of saying focal reduction in the appearance of lung markings this is due to both lack of blood flow distal to an embolus as well as redistribution of blood to other adjacent areas can you spot the Westermarck sign in this film lastly is flash nurse sign which is a prominent central pulmonary artery caused by distension of the vessel as a consequence of a large PE in this case we can see both flash nurse sign as well as Westermarck sign more peripheral to it the final topic in this video is cavitation there are many ideologies of a cavitating lung lesion pneumonia most commonly staph Pseudomonas or Klebsiella in this case the patient has a necrotizing right lower lobe pneumonia due to aspiration long abscess which is sort of a special and extreme case of cavity pneumonia tuberculosis one of the most common causes of lung cavitation worldwide pulmonary metastasis of which squamous cell carcinoma is the most common to do this here is an x-ray of an IV drug abuser with HIV who had septic pulmonary emboli presumably from right-sided endocarditis about 5% of pulmonary infarct scabbit 8 here's an 86 year old woman who actually presented with failure to thrive and amazingly had no acute pulmonary symptoms a CT angiogram here showed a large central PE granulomatosis with polyangiitis formerly known as Wegener's granulomatosis cavitary masses in this condition can be either thin or thick walled can be very variable in size and somewhat uniquely they can wax and wane over time rheumatoid nodules in the lungs can cavitate and finally a new mana seal should be considered particularly when the nodule or mass is thin-walled and occurs in the aftermath of an acute pneumonia patients at this stage can be surprisingly asymptomatic and amount of seals usually resolve over time provided that appropriate antibiotic treatment for the pneumonia was provided when cavitary like process make sense to also mention here and that as an aspergillum a-- aspergillomarasmine pre-existing lung cavities that become colonized with Aspergillus like the mana seals these can be surprisingly asymptomatic but may also be associated with a chronic cough these are also known as fungus balls so that concludes this video the next one will cover both unelect assists as well as lines tubes devices and prior surgeries [Music] you