I was texting with a vet school classmate last night, and mentioned that we take radiographs of some of our necropsy cases. You take post-mortem rads? She was clearly surprised. After thinking it over, I realized that it does sound odd to a GP vet that we would do that.
There are three types of necropsy cases for which radiographs can be quite helpful. The first type is gunshot suspects--we want to see if there are any metal fragments in the body and where they might be. The second type is abuse suspects--we want to look for, and document, any bone fractures. Animal rescue groups and municipal shelters and animal control usually submit these two kinds of cases, but I've had vets submit gunshot cases directly. In one memorable case, I discovered what looked like projectile entry wounds on a dog when I was examining it before starting the necropsy. But the submission form didn't mention a thing about gunshots! So I called the vet, and she admitted that she had not seen the animal herself. The neighbors had taken the dog to the vet, but it unfortunately died on the way, and the vet clinic passed the dog directly on to the lab without a thorough examination. Using the radiographs that I made, I was able to find a lead pellet lodged in the descending aorta that was the cause of the animal's death. The third type of case is a more generic legal case in which radiographs are another diagnostic tool. Racehorses sometimes fall into this category. They are usually insured to the gills, and we are asked by owners or the racetrack vet to perform a complete necropsy, even though, for example, the fractured cannon bone in a front leg is the obvious problem.
Our veterinary diagnostic lab does not have any radiographic equipment. So we rely on the generosity of the State Crime Lab which is literally next door to us. We all get gold stars for the inter-agency cooperation, but I try not to abuse the privilege. They are a busy lab. The State Crime Lab handles cases of humans who died under suspicious circumstances. Which means they have dead people there. Lots of dead people.
When I need rads for a necropsy case, I text one of the techs at the Crime Lab and set up an appointment. For small animals, we get rads before starting the necropsy. One of my techs and I will load our case, double bagged, into the back of a vet lab truck and drive next door. We back up to the dock of the Crime Lab and unload our case onto one of their gurneys. A human-sized gurney. We then follow the Crime Lab techs into a large, walk-through cooler where they store their cases. Dead people, each one enclosed in a body bag. It's super fucking creepy, and after the shock of my first trip through, I keep my eyes forward and try not to glance around. I've seen that cooler room stacked with literally dozens of bodies. Super. Fucking. Creepy. One of my techs refuses to even go to the Crime Lab, and I don't blame him for a second.
We keep our cases bagged at all times out of respect for our Crime Lab
colleagues. They don't want to see what is in our bags any more than we
want to see what is in theirs.
Their xray room is just beyond the cooler room. They have a very nice rig, all digital, quite similar to what I've seen in vet clinics, except that the table is human-sized. I bring a flash drive with me.
Taking clear, diagnostic radiographs of humans and animals is both a science and an art. There is a balance between resolution, energy of the beamed particles, and radiation damage to the patient and techs. But since neither lab is dealing with living patients, there is a lot less fiddling and more just blasting some xrays and taking a look at the result on the monitor. We don't use radiographs to FIX a problem, we use them to FIND a problem.
Horses represent a unique situation since the Crime Lab doesn't have a hoist, or any facility that could deal with such a large animal. We usually remove the part of the horse that we are interested in, most often the leg. But I did have a case in which the racetrack vet insisted that we do a more thorough examination of the caudal (neck) vertebrae. Without going into a lot of detail, my techs and I removed the neck, all seven caudal vertebrae plus the first two thoracic vertebrae, and bagged that up to carry to the Crime Lab. The rads revealed an old, poorly healed fracture in C7 and a new fracture in C2 that happened when the horse fell over as it was dying. It died from something called EIPH, exercise-induced pulmonary hemorrhage, a progressive, chronic disease. In this case, all of the horse's lungs filled up with blood very rapidly. That's a lot of lung, and a lot of blood. But that C2 fracture wasn't compatible with life either. Once we got back to the necropsy floor, we used the radiographs to precisely section the neck and photograph the fractures directly. Very interesting case that was greatly enhanced by post-mortem rads.
Working up a necropsy case requires an array of qualitative and quantitative diagnostic tools--gross examination (sight, touch, smell), bacterial culture, PCR tests, radiographs, even blood tests. The art comes in navigating the messy matrix of making a good differential list, obtaining the right samples, and selecting the right diagnostics for each case. Sure, anybody can run all the tests on every case, but what's the purpose of that? It is far more challenging, and satisfying, to find the most elegant path through the matrix.
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