Just how effective is an MRI at detecting a transient ischemic attack or TIA?

Well, when compared to a CT scan, an MRI “is more sensitive when evaluating someone for a TIA or stroke,” says Rob Lapporte, MD, board certified in emergency medicine and chief medical officer of Physician 360, a telemedicine service.

But neither the MRI nor CT scan can show that a transient ischemic attack occurred, continues Dr. Lapporte.

However, an MRI “can be helpful in a TIA workup in two ways,” he says.

“One, if the MRI shows evidence of an infarct [tissue death from blocked blood supply] or hemorrhage, then it rules out a TIA.  This patient would now be diagnosed with a stroke.

“Two, if the MRI does not show any evidence of acute infarct or hemorrhage and the symptoms are consistent with a TIA, the diagnosis can be made.”

A transient ischemic attack, due to its temporary nature, will not result in tissue death. The clot that transiently blocks blood supply dissolves before an infarct can happen.

A hemorrhage results from a hemorrhagic type of stroke, and a TIA is not related to this kind of stroke.

A TIA is sometimes called a mini-stroke, and it is the transient or temporary version of an ischemic stroke. Ischemia refers to insufficient supply of blood.

Though an MRI is more sensitive than a CT scan at revealing signs that a TIA probably occurred (due to ruling out signs of a stroke or brain bleed, in combination with evaluating symptom descriptors from the patient), Dr. Lapporte points out that the MRI “is more time consuming and labor intensive.”

Conclusion

“There is no test for TIA,” states a report in Practical Neurology (2014 Feb; 14(1): 23–31). The report adds that “the gold standard remains assessment as soon as possible by a clinical expert.”

Dr. Lapportedr. lapporte has been practicing evidence-based clinical medicine in emergency rooms and urgent care centers for almost 20 years.
Source: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3913122/