Radiology #3: Phone a Friend

The Patient

You are busy on the ward when one of the medical officers messages you asking for advice regarding a chest x-ray. He sends you a photo of a portable film taken in Resus, which can be seen below:

The Pictures

What do you think?

click to reveal the answer

Following an "ABCDE" approach, the main findings are as follows:

A - Airway - it's difficult to see because of the superimposed moiré pattern that happens when you take a photo of a screen, but there doesn't seem to be any gross deviation of the trachea to one side or the other. A "moiré pattern" is a type of interference that occurs when the pattern of the screen (which is a grid of pixels) interacts with the pattern of the camera's sensor (also a grid of pixels). The overlapping grids creates a new wavy set a of zebra stripes that wasn't part of the original image. 

B - Breathing - there is a veiling opacity of the right hemithorax, which along with the blunting of the right costophrenic angle suggests a haemothorax. There is some additional airspace opacification in the right lower zone that looks like pulmonary contusion or collapse. On the left, you could be suspicious that there's a retained pneumothorax, as there's what appears to be a pleural line about 2cm from the chest wall at the level of the hilum, with no visible lung markings beyond it. There's also a relative radiolucency of the left hemithorax, but this can be due to the contrast that naturally occurs against the veiling of the contralateral side. Photos taken with your phone will tend to exaggerate this, as phones automatically adjust the brightness and contrast of a photo to highlight the details within it - in this case highlighting the features of the left chest.

C - Circulation - there's no obvious abnormality of the cardiomediastinal contour.

D - Diaphragm and deformities - as mentioned above, there's that rounded meniscus of radioopaque blood that's blunting the right costophrenic angle. The full extent of the left hemidiaphragm isn't visible, but there's no obvious subdiaphragmatic free air.

E - Everything else - there's a displaced fracture of the right 8th rib posteriorly, and a significant volume of subcutaneous emphysema in the right chest wall. Two intercostal catheters can be seen; the right is poorly positioned, with its tip abutting the mediastinum, and the left has has been directed very basally with its tip in the medial part of the costodiaphragmatic recess. Both are well secured - you can tell this because of the "cinched" appearance they get when the Soweto knot is nice and snug.

In addition to being a busy x-ray with lots of interesting findings, the main take home point here is to be careful when reading imaging that's been photographed. Glare and screen reflections, moiré patterns, and the exposure adjustments that your phone automatically makes can all obscure important findings.

At Bara our access to PACS is limited and we still rely on physical plain films, which must be developed and printed and looked at on a lightbox. However, if these are bedside x-rays and not those taken in the main radiology department (which is the case for most Resus patients), typically radiographers will not to print them out for us. This means we often rely on photos taken of the portable x-ray machine's screen.

How many abnormalities did you find on this chest x-ray? If you found anything we missed, let us know by using the contact form on our homepage.

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Thanks to Dr Nick Chapman for submitting this case.