POTD: Eye Stuff (Trauma Tuesday!)

Adam Ranginwala · October 6, 2020 · Ophthalmology, Trauma

Seidel's sign: Fluorescein stained vitreous flowing from the site of globe perforation. Should protect the globe from any external pressure with eye shield, elevate head of bed 30 degrees, analgesia, control hypertension, and prevent vomiting. Emergent Optho consult.

Teardrop pupil: Usually indicated globe rupture/ FB. See management for Seidel's sign above.

Corneal foreign body with rust ring: remove foreign body, urgent follow up for rust ring removal which should be done after 24 hours from initial injury- this is because reepithelialization makes removal easier.

Exophthalmos: if in setting of trauma with increased intraocular pressure suspect retrobulbar hematoma. Obtain STAT CT scan, perform STAT lateral canthotomy and emergent optho consult.

Hyphema: Blood in the anterior chamber of the eye. Elevate head of bed, control intraocular pressure. Patients on anticoagulation or antiplatelet agents should be admitted for reversal and observation. Consult ophthalmology depending on size of hyphema and rebleed risk.

Stay well,

TR Adam

POTD: How to measure Hounsfield Units?

Adam Ranginwala · September 25, 2020 · Radiology, Trauma

Today we will show you how to actually measure HU on our radiology software, Medview/ PACS.

First open the CT and find the slice where you would like to measure the HU of a particular area. In the first image below, we see some free fluid around the liver which we would like to know whether it is blood or ascites.

Follow the steps in the images below and your HU measurement is on the second line. In this case, the free fluid in this patient's abdomen had a HU of 19.5 which is consistent with ascites.

Stay well,

TR Adam

Right click on the image to open the following menu bar

Go to "Annotation Tools" on the menu bar and find and click on "ROI- Rectangle:"

Now create a small box (drag your mouse) over the area you would like the measure the HU. Make sure not to overlap over another area of the slice or it will distort your measurement. You may want to magnify the area you would like to measure

POTD: Free Fluid in the Belly (Trauma Tuesday!)

Adam Ranginwala · September 23, 2020 · Radiology, Trauma

This POTD was inspired by a morning report I was present for in Shock Trauma. The case was a 40ish male involved in an MVA. Patient was "shan scanned" for blunt traumatic mechanism. Surgeons saw a ton of free fluid on the scan and took patient directly to the OR. No intra abdominal injuries nor hemoperitoneum were found in the OR. It was later discovered, the patient had a drinking history w/ a cirrhotic liver and the free fluid initially assumed to be blood was actually acetic fluid.

PODT: Free Fluid in the Belly

So you have a trauma patient with a history of alcoholic cirrhosis. Your FAST is positive but your are unsure whether the free fluid you are seeing is blood from the trauma or the patient's chronic ascites.

You Pan-CT the patient and again all you see is free fluid, unable to tell if what you're seeing is blood or ascites. Your vitals, labs may help guide you. You can also potentially do a diagnosis parenthesis if there is a big enough fluid pocket but this is a very invasive procedure.

What you should do, is look at the Hounsfield Units (HU)!

HU are built into most imaging software and can be used to measure the radiodensity of the material on CT to help distinguish various structures.

Uncoagulated blood typically measures 30 to 45 HU

Clotted blood measures higher at 60 to 100 HU

Ascites/ Plasma measures around 0 to 20HU

So there you have it. You can use HU while looking at your CT images to help you determine whether your trauma patient is bleeding into their belly or what your seeing is more chronic.

TR Adam