The study below looks at the utility of emergency MRI to diagnose MS relapses and confirms that it is worthwhile, i.e. 87.5% of MSers with exacerbations, or relapses, had active scans. They also mention that pseudo-exacerbations occurred in 18 patients, with almost all having inactive scans.
I worry that neurology, like so many other areas of medicine, is increasingly becoming dependent on technology rather than clinical skills. Please note that our current definition of a relapse does not require an MRI to confirm the diagnosis of a relapse. In someone with established MS who presents with a relapse do you need an MRI? In the majority of cases you don’t. The question you need to ask yourself is how is the result of the MRI going to change your practice? Will it change your decision to use steroids or not? Will it change your diagnosis from a relapse to a pseudorelapse? If the answer to the latter question is yes then you need to ask what the sensitivity and specificity of MRI in this situation is. I am not aware of any studies that have been done to address this question. These issues raise the question of what is a relapse and what is a pseudorelapse?
I think I know what causes pseudorelapes, but I have difficulty defining it as a clinical entity. Are they all relaspes that don’t fulfil our current definition of a relapse? Now that we are doing annual Gd-enhanced MRI studies on all of our patients on DMTs, t oo many patients with transient, or intermittent, symptoms have evidence of active disease on MRI in the last 12 months. I therefore think that we shouldn’t dismiss transient symptoms as being insignificant and that our current definition of what is a relapse is far too restrictive. At present we define a relapse as ‘the appearance of new symptoms, or the return of old symptoms, for a period of 24 hours or more – in the absence of a change in core body temperature or infection’. This definition does not allow us to make a diagnosis of a relapse in patients presenting with new symptoms, that are not associated with focal neurological signs for example, cognitive issues, fatigue, sleep disorders (e.g. narcolepsy), Lhermitte’s sign, flexor spasms, trigeminal neuralgia, etc. In trial protocols the definition of what is a relapse is even more restrictive and typically require patients to move on the EDSS and/or one of the functional systems (FS) (one FS by at least 2 points or two FS by at 1 point). This is why when you read the results of trials we often discuss protocol and non-protocol defined relapses; the former fulfils a strict definition based on metrics and the second is based on the call of the assessing neurologist. Who do you believe? I think we need to reassess our definition of what is a relapse and seriously think about how we define pseudo-relapses in MS.
Pakpoor et al. Emergency Department MRI Scanning of Patients with Multiple Sclerosis: Worthwhile or Wasteful? AMJNR Published online before print October 6, 2016, doi: 10.3174/ajnr.A4953
BACKGROUND AND PURPOSE: The increasing use of the emergency department MR imaging scanner at our institution raises questions about its added value to certain patient groups. We hypothesized that the use of emergency department MR imaging for identifying active demyelination in MS patients presenting with new neurologic symptoms would be of low yield.
MATERIALS AND METHODS: Electronic medical records were reviewed for patients with MS who had emergency department MR imaging scans for a suspected MS exacerbation between March 1, 2014, and March 1, 2016. Details surrounding patient disposition, imaging, diagnosis, and management were determined.
RESULTS: Of 115 patients in our study, 48 (41.7%) were ultimately diagnosed with an MS exacerbation. Nearly all patients with MS exacerbations (87.5%, 42/48) had active demyelination on their emergency department MR imaging, identified on 30.6% (33/108) of brain MRIs and 20.4% (19/93) of spinal MRIs. The presence of active demyelination at MRI was significantly associated with the ultimate diagnosis of an MS exacerbation (P < .001). MR imaging activity isolated to the spinal cord (ie, not found on concurrent brain MR imaging) was present in only 9 of 93 (9.7%) cases. Pseudoexacerbations accounted for 18 of the alternative diagnoses.
CONCLUSIONS: Emergency department MR imaging is a worthwhile endeavor from a diagnostic standpoint for MS exacerbations despite not being part of the diagnostic criteria. This finding has corresponding downstream impact on management decisions to admit and/or administer intravenous steroids. However, we raise the question of whether clinicians over-rely on emergency department imaging for making exacerbation diagnoses. Additionally, spinal MR imaging is of questionable value as an addition to brain MR imaging due to a low yield of isolated spinal disease.