Chest X-ray: Lung Pathology IV

Okay, here is the last article in the Chest X-ray series for now. We will do a quick and very brief job at covering pulmonary vasculature. As a note, this lecture is largely anecdotal, meaning this is based upon personal experience and makes sense to me but was not learned directly from any single textbook but a mash up of multiple books, mentors, and my own observations.

Let’s talk about fluid overload in the lungs. This stuff is really cool and relates mostly to Stark’s Law (not Tony a.k.a Iron Man). The law incorporates hydrostatic pressure and oncotic pressure. Hydrostatic pressure is caused when fluid exerts pressure on the walls of the lumen of a vessel. This pressure wants to push fluid from within the vessel through the walls causing leakage. The higher the pressure the more leakage you will likely have. Oncotic pressure refers to pressure exerted on fluid to balance out an osmotic gradient (i.e. more stuff in one compartment than the other). The more stuff you have in one compartment the more water wants to “dilute” the substance driving water to the side with the most amount of stuff. There are proteins in your blood that want to drive fluid into the lumen of the vessel to balance out the protein in the blood. So, in general, hydrostatic pressure pushes fluid out of your vessels and oncotic pressure counterbalances drawing fluid into the vessel. These forces will reach an equilibrium. Basically too high of pressure in the blood vessels (hypertension) and too low of oncotic pressure (malnutrition) can cause fluid to leave the blood vessels.

cropped-pa-chest-e1533275854954.png
Normal chest x-ray

Well that was kind of boring. Let’s get to the images. If fluid leaks out of the pulmonary vessels, it can be visualized on chest X-ray. Personally, I like to break the phenomenon down into three discrete and identifiable entities that I feel have a correlative physiologic process. These processes will often occur along a continuum if not corrected. I describe these process in my X-ray reports as pulmonary vascular congestion, pulmonary interstitial edema, and pulmonary alveolar edema.

 

PULMONARY VASCULAR CONGESTION

Here the hilar vessels lose their nice circumscribed margins, which become hazy and ill-defined. This is often a minor finding and can be over called in chest X-rays with low lung volumes or portable technique. I like to look at the vessels to the right of the carina. Here when looking down the barrel of the vessel/en face, the vessels look circular and can be pretty much outlined with a pencil line, like above. But when engorged they become less distinct and fuzzy, like below.

CXR - PVC
Pulmonary vascular congestion

PULMONARY INTERSTITIAL EDEMA

Here, the findings should not be a diagnostic dilemma. The hydrostatic forces exceed the oncotic forces and fluid is pushed outside the cells and backs up into the space between cells called the interstitium. When this happens the intercellular markings are increased and can form these lace-like opacities or thin lines at the periphery of the lung called Kerley B lines (yeah, let me know if there is anything stupid left to put my name on). Additionally, the lungs have a gradient with more blood vessels near your feet than head. When pulmonary blood pressure goes up, the vessels at the top of the lungs eventually become engorged with fluid, called cephalization of the pulmonary vasculature.

CXR - pulm int edema labeled
Pulmonary interstitial edema

PULMONARY ALVEOLAR EDEMA

This is when things are getting dire. Fluid has now filled up the interstitium and are backing up back into the air cells. This eliminates the possibility for air exchange and patients are pretty much drowning in their own fluids. When this happens the fluid fills the airspaces and patchy opacities may be present at the bases, with or without pleural effusions.

CXR - pulm alv edema with effusion
Pulmonary alveolar edema with bilateral effusions

So that’s it. A brief tour of pulmonary fluid overload. I’m going to try and break into vlogging and see how it goes. So…. stay tuned for FLUORO!!!

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I am an American Board of Radiology certified Diagnostic Radiologist with a certificate of additional qualification in Neuroradiology. I absolutely love my job. I have learned a tremendous amount about the human body, including its’ expected complications given our extraordinary complexity, and get to use that knowledge to help people. I personally have experienced emotional devastation and loss, which has made me compassionate and empathetic. I really care about people, and I hope I can use this site to help you. I graduated medical school in 2004 from New York Medical College. My wife and I had our first son in NY where we bought our 900 sf two bedroom one bath starter home. I stayed at Westchester Medical Center for radiology residency, where we had our second son. I obtained a neuroradiology fellowship position at Yale New Haven Medical Center commuting about an hour and a half each way for a year while we had our third boy. Upon graduation I was fortunate to return to Westchester Medical Center to work in Neuroradiology, Body Imaging, and Women’s Imaging departments, a rarity in academic medicine. Almost a decade later and I am living in a larger home in Reno working in a private practice community based outpatient radiology group which contracts with a rural hospital in Elko, Nevada. My wife and I now have four boys and gave up on the girl. We also have a male Bernese mountain Dog named Helmut and female Newfoundland named Lucy. Despite all its hardships and tremendous struggles, I have an absolutely amazing life, which is a gift I cherish. It’s down to my philosophy. I am a firm believer in teamwork. So much comes down to communication. When healthcare providers talk to each other one-on-one, the patient care is always improved, every time! We might not find an answer to your problem, but our collective knowledge sure can help improve your chances. At Yale the best conference I ever regularly attended was a head and neck tumor board. The head and neck surgeon (otolaryngologist = ENT) presented the patient’s clinical history, the radiologist showed the images, the oncologist discussed the tumor and chemotherapy options, and the patient came to the conference and we all did a physical exam looking into their mouth to directly visualize a tumor. It was incredible! Patients came from far and wide to see this highly trained, world-renowned, humble, Japanese, gentleman surgeon. It was also an epiphany. I found that when I see the patient, talk to them, listen to their story, examine them and discuss the patient with my colleagues, the patient felt better and I had a lot of fun. It’s weird but reminds me of seeing a comedy where it is always funnier in a packed theater with everyone laughing. Knowledge and compassion are both infectious and contagious. My greatest days are helping patients deal with some of their most difficult days, and I am good at it.

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