Diffusion-Weighted MRI Becoming Major Tool to Diagnose Patients with Transient Ischemic Attacks

With the development of brain imaging, including cranial computed tomography (CCT), and particularly diffusion-weighted imaging-magnetic resonance imaging (DWI-MRI), the diagnosis of transient ischemic attacks (TIAs) has changed from time-based definition to a tissue-based one. DWI-MRI became an essential tool in the TIA workup.

Several studies have shown that TIA patients had cerebral infarctions that can be identified by CCT, even though the CCT was performed days to weeks after the TIA. It has been found that 3%–48% of patients with clinical TIA symptoms had acute cerebral infarctions that can be visualized by CCT. Moreover, the DWI-MRI measurements have shown that up to 67% of patients with TIA demonstrate relevant cerebral infarction.

The development of brain imaging and its use in the routine diagnostic workup of patients with TIA has therefore changed the investigators outlook of TIAs. Particularly, the definition of TIA has shifted from a clinically time-based term to tissue-related one in the clinical daily routine.

The risk of stroke after TIA in patients with evidence of acute infarction ranged between 3 to 18-fold higher than TIA patients without acute infarction detected by MRI. Therefore, TIA should be handled as an emergency event and patients suffering from TIA should be immediately treated to evaluate the etiology and to receive the secondary prophylaxis to prevent a stroke. The impact of the immediate evaluation of TIA patients on stroke prevention after TIA has been shown in earlier studies. Conversely, there are no uniform international guidelines and recommendations for TIA diagnosis and treatment, particularly in diagnostic and therapeutic procedures.

The DWI-MRI provides not only the evidence to differentiate between TIA and acute ischemic stroke; furthermore, it predicts TIA patients who are at higher risk of disabling stroke, which can be prevented by an immediate evaluation and treatment of TIA, according to Dr. Mohamed Al-Khaled from the University of Lübeck (Germany).

The brain imaging in patients with transient neurologic symptoms can help to answer the question that whether patients with TIA who have an acute infarction should be classified as acute ischemic stroke. Furthermore, it has been established that TIA patients who showed acute infarction by DWI-MRI or CCT are at a higher risk to suffer from an incapacitating stroke.

These findings were published in the June/July 2014 issue of the journal Neural Regeneration Research (2014; vol. 9, no. 3).

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University of Lübeck