I am sorry to hear of your symptoms. The best test to look at the cauda equina is an MRI of the lumbar spine. However, it sounds as if the doctor you saw was arranging to investigate your for pain rather than your urinary symptoms. If this is the case and clinically he feels the pain is from your hip then this may be the reason why the hip MRI has been ordered. If you have not already had the scan it may be worth clarifying the exact test that has been requested - it may be that they have arranged to look at both regions using one scan time if this is felt to be clinically appropriate. However, a standard protocol would not optimally image both regions. I would advise discussing your symptoms and concerns with the referring doctor in order that the correct test(s) can be performed as promptly as possible. It may also be worth clarifying whether contrast will be used, but this decision will rest with the radiologist rather than the referring doctor and may not even be decided until the day of the investigation when initial images are reviewed.
Thank you Dr. Beattie. This response has been extremely useful. I will now clarify with my consultant regarding why he has ordered the test and that I would like the cause of my urinary problems to be evaluated as well as my hip pain. Also on the day of the test I will check again with the radiologist. The appointment leter said 'hip MRI + c' so I assumed the '+c' meant plus contrast? I have read on other parts of this forum that it is always better to use contrast as more information is available. But I don't know whether I can directly ask for it or if it is entirely the decision of the radiologist. I do have a history of a number of tests which were not done in great detail, I feel wasting NHS time and resources as well as my time, and am keen now that when an expensive test is ordered it is done thoroughly so it does not have to be repeated in the future. But I don't know how much of a voice I have. Few doctors will listen to patients suggesting to them how to do their jobs, and it has been frustrating for me in the past when I know the wrong test was being done and consequently unhelpful results obtained. I don't want this to happen this time. A pelvic MRI is something I have desired for many years given my symptoms. I want them to get it right as for me this could be the most important test of all I have had to date. With such high expectations maybe I am setting myself up for disappointment, but the least I can do is take your advice and ensure I get my concerns through to my consultant and the radiologist. It is all I can do as a patient. I cannot order the form of the test myself, unless I go private. Behind all this angst is gratitude that I am getting this for free on the NHS, there is no way I can pay for private, and because of my pre-existing complex conditions and medical history, no insurance company will take me on. The expression 'beggars can't be choosers' sadly springs to mind. I know you are in Scotland, whereas I am English, but I asked for your input as you know better the system here, unless it is very different in Scotland. Thank you again.