Why a dog waits three weeks for an MRI
Ask a general practitioner how long it takes to get a dog through an MRI and you will usually get a shrug and a range. Three weeks is a reasonable middle. What that number hides is that almost none of it is scanning time.
Where the three weeks actually go
The scan itself takes twenty to forty-five minutes. Everything else is queueing, and the queue has structure.
Day 0 — presentation. A dog comes in non-weight-bearing, or with a neurological deficit, or with a soft-tissue swelling that does not resolve. You examine, you radiograph, and radiographs answer a different question than the one you are asking. You start empirical treatment, because doing nothing for three weeks is not an option.
Days 1–3 — the referral decision. This is the step that quietly determines everything downstream, and it is not a clinical decision. It is a conversation about money. A canine MRI commonly runs a client somewhere between $2,300 and $5,000 once anaesthesia and interpretation are included. A meaningful proportion of clients say no at this point, and that case leaves the pathway entirely — not to a different diagnostic route, but to indefinite empirical management.
Days 3–18 — the wait. If the client says yes, you are now in someone else’s calendar. Referral MRI slots are scarce because the machines are scarce, and the machines are scarce because each one requires a shielded suite, a cryogen contract and a capital outlay between $150,000 and well over $1,000,000. Scarcity is not an accident of scheduling; it is a direct consequence of what the hardware costs to own.
Day 18 — the referral visit. The patient travels. For a large-breed dog in pain, or an elderly cat, the journey is not neutral.
Day 21 — the study. The patient is anaesthetised, because MRI requires stillness and you cannot ask a dog to hold its breath. General anaesthesia in dogs carries an anaesthetic-related mortality of roughly one in two thousand; in cats, roughly one in nine hundred, measured across more than a million anaesthetic episodes. Those are small numbers and they are not zero, and every clinician weighing a diagnostic MRI in a fourteen-year-old patient is weighing them.
The part nobody counts
The three weeks are visible. The cases that never enter the pathway are not.
When a client declines a referral MRI, the practice records a declined referral. What actually happened is that a diagnosis did not get made, and a patient was treated on a best guess instead. There is no line in the practice management system for that, and no way to audit how often the guess was wrong.
This is the number we would most like to know, and the one we cannot find published anywhere: what proportion of soft-tissue and neurological presentations in general practice would be imaged if imaging were available in the building at a fraction of the cost?
What would have to change
Nothing about the referral pathway is irrational. Each step is a sensible response to the constraints of the equipment. Which means the pathway only changes if the equipment changes — specifically, if a scanner stops requiring a shielded room, a cryogen supply, a dedicated operator and a general anaesthetic.
That is what we are building, and we are not going to pretend it is finished. A low-field system does not resolve what a 1.5T system resolves; that is physics, not marketing. The question we are trying to answer with veterinary clinicians is a narrower one: is a study that can happen today, in your own building, in a single anaesthetic episode, worth having for the cases that currently get no imaging at all?
If you have a view — particularly a sceptical one — we would like to hear it.