#wetreadanswer

Answer: Ischemic Bowel 

Fluid filled ?dilated bowel loops? YES

So they all look the same? No

Right abdominal loops (red) = thickened w/o enhancement vs those in the left abdomen (blue) which = early obstruction or ileus. 

 Surgery=necrotic bowel!   

Small Bowel Ischemia 

  -life threatening EMERGENCY!! 

- +wall thickening +/- dilation 

-absent enhancement (use other bowel for comparison) 

-bowel wall hyperdensity can be due to intramural hemorrhage (can  on non-con!) so I look at the mucosa 

-pneumatosis = infarction ( for PV gas!)

-CTA helpful to look for arterial etiology (majority) 

-Also venous occlusion, systemic hypoTN (shock bowel), trauma, obstruction (ie closed-loop). 

 -Don't forget this on non-con exams! UGLY segment of bowel +  lactate =  CALL SURGERY!! 

Answer: Unilateral Facet Dislocation 

Normal L & R superior articular facets overlap/aligned to the C6-C7 where 1 is shifted anterior(red dash) 

 -Ant & post vertebral lines (green) ?ok 

-Spinolaminar line (orange)=broken

 -Poseriort spinous line (purple) = gap

Perched facet = subluxed joint with tip of inferior facet resting on tip of super facet of lower body 

Dislocated/jumped/locked facet = complete dislocation with inferior tip ANTERIOR to superior facet of lower body (thus "locked") 

 Get the CT and ALWAYS look for the fracture!

Unilateral jumped facets can be tough on X-ray as the vert body doesn't have to displace much (vert lines ok). 

ALWAYS look at spinolaminar & posterior spinous lines! 

 Facets = "shingles on a roof" 

 Any abrupt change/rotation should be concerning!

For completeness, here is a bilateral facet dislocation. 

ALL spinal lines disrupted. No rotation. Both inferior facets jumped and locked anterior to the superior facets of the lower body. 

 - MRI=diffuse ligamentous injury

- neurologically devastating

Answer: Bochdalek Hernia 

 Large round opacity right lung base. 

On frontal does NOT obscure anterior diaphragm or R heart border - ie posterior/RLL 

On lateral DOES "obscure" entire posterior R diaphragm

-congenital defect in posterior diaphragm attachment 

- Can be either side (classic =L side in symptomatic infantslung hypoplasia, but R m/c in adults?) 

- typically only fat but ~25% can contain abd organs 

 Hint: Bochdalek = Back

Answer: Psuedosubarachnoid hemorrhage secondary to hypoxicischemic brain injury

In these 2 images we see hyperdensity (increased attenuation) along the basilar cisterns. While this is a common appearance of subarachnoid hemorrhage secondary to Circle of Willis Aneurysm rupture, we need to look at the entire image and the entire exam!

How about the basilar cisterns? - They are effaced

How about the grey-white junction?  - It is gone.   In fact, Normally grey matter is slightly hyperdense compared to the white matter, but here we have the peripheral grey matter actually lower in density than the central white matter (aka the reversal sign)

How about the central grey matter structures?  Similarly, the caudate nuclei, basal ganglia and even thalami are all low in density - which again is not normal

How about the normal sulcal pattern of the cerebrum?  - It’s gone. In fact can you even find a sulcus? (and the patient isn’t 15 years old)

This is an example of global anoxic injury aka hypoxic-ischemic encephalopathy. Global anoxia leads to neuron injury. Since grey matter is more metabolic than white matter, it is effected earlier and more severely. Anoxia/Ischemic -> neuron injury -> edema -> decreasing grey matter density.

So what about that increased density all throughout the basilar cisterns, sylvian fissure, falx and tentorium?  While it may look like blood, it’s actually artifact - ie pseudosubarachnoid hemorrhage. 

Because of the cerebral edema, particularly the grey matter edema, the parenchymal density decreases. This combined with outflow venous dilation and thrombosis secondary to the increasing intracranial pressure, yields the appearance of increased density particularly throughout the basilar cisterns.