Well, here is my view. Ideally, people want to get an MRI so that they know what is going on. But in the case where this is going to be very costly, and there are already some obvious symptoms, and a person is not going to be opting for surgical treatment regardless, for whatever reasons, I would make it clear to a neurologist that you cannot manage the cost of an MRI but that you would like to have a clinical exam done and have their opinion and then to start trialing some of the possible medications to see if those help.To be honest, all evidence indicates that 70% of all cavaliers would MRI with a syrinx by the time they are 6 or 7 years old. and almost every single cavalier is going to MRI with CM. That means for a given set of symptoms, for most dogs the conclusion is going to be that they have CM/SM, and they are going to be treated accordingly. For many different types of possible illnesses, vets will try medications to see if they help before doing invasive tests, and so I feel quite strongly that in the case of an MRI, which can cost people 1000 or 2000 pounds, euro, or dollars, for most dogs showing symptoms that are generally tied to this condition, it makes more sense to simply trial them on medications to see what works. This is of course after a vet has done everything else to eliminate other possibilities–allergies, disc disease, etc.None of the medications used to treat SM are particularly risky, and certainly there are not going to be significant side effects, if any effects at all, for most of them used for short-term trial periods. Some of the symptoms are just so typical that most of us that have affected dogs reach a point where we could probably say with a pretty high degree of accuracy whether some other dog, scratching or behaving in a particular way, has SM. When other possibilities have already been eliminated, I honestly do not understand sometimes why people are pushed to do a costly MRI unless they either want to have a confirmed diagnosis and understand the extent of existing damage, or they want an MRI to consider the option of surgery.Or to put it another way–I have MRI'd all of my dogs, some of them twice, for the purposes of both diagnosis and research. I have worked with a neurologist and with my veterinarian to treat those that have SM. I have not considered surgery for any of the 3 that have SM, for a variety of reasons. If that were to change, then those dogs would go for a full MRI. 2 of my dogs that have SM did not have this confirmed by MRI for a couple of years, until I took them to the UK to have all of them done for research (mainly to get a 2nd MRI on my 2 related Cavaliers, one of which has SM and one of which is clear for reseacrhers, and also to have an MRI done on my lovely, late Lucy, whom the researchers expected would be a clear older dog at 9 given the dogs in her pedigree–and she was–thus making her very helpful for the genetic work the researchers are doing). So out of 3 with SM, one got an MRI confirmation when he was only just over a year old, and he was then treated by medications from that point onwards with a confirmed diagnosis–and he is now 8.5. The 2 others, I was quite sure from symptoms and from response to medications, that they had SM and it turned out to be the case. But they were successfully helped by medications long before they had an MRI confirmation.I do think dog owners should politely hold firm if they do not feel they can afford an MRI And would not seek the option of surgery–ask for a clinical exam and ask trial medications if the neurologist feels, on the basis of the clinical exam, that the dog is likely to have SM. there are obvious downsides to this: it may be that an MRI will reveal the dog really has very little time or chance of much of a life unless surgery is performed, and without an MRI, the owner will not know and choices may become more limited down the road. So there are many things to weigh in the balance, and many considerations, but I personally feel not every dog needs to have an MRI in order to be effectively treated (especially older dogs–say, over 4-5– that are showing symptoms, especially if they are not really severe).