Evaluation of the HARM for the Detection of a Cerebral Ischemia in TIA/TNA Patients

The research project investigates the incidence of the hyperintense acute reperfusion marker (HARM) in patients with transient ischemic attack (TIA) or transient neurological attack (TNA). Initially, HARM was described after acute ischemic stroke and is caused by a blood-brain barrier disorder after recanalization of an acute vessel occlusion and consecutive reperfusion. These result in a contrast agent extravasation into the subarachnoid space, which can be easily detected on fluid attenuated inversion recovery (FLAIR) images.

TIA is defined as a transient focal neurological deficit with a probably cerebrovascular cause. In contrast, TNA is defined as a transient non-focal neurological deficit with multiple causes, including cerebrovascular. The clinical diagnosis of TIA is often flawed and the delineation of TIA and TNA can be difficult. MRI is the most important diagnostic method for the detection or exclusion of cerebral ischemia in patients with TIA/TNA in daily clinical practice. However, on diffusion-weighted imaging (DWI) approximately two-thirds of TIA cases and only one-fifth of TNA cases demonstrate acute cerebral ischemia. Supplementary perfusion-weighted imaging (PWI) scans can only slightly increase this percentage. The well-known HARM could prove to be complementary to DWI and PWI and close or at least reduce the existing gap. In the case of TNA in particular, this could be of clinical relevance in order to avoid mistreatment or even dismissal without further clarification after supposedly inconspicuous imaging.

Therefore, the aim of this study is to record the incidence of HARM in a statistically significant number of cases of patients with TIA and TNA and to investigate relationships with symptom duration and anatomical localization. In addition, the dynamics of contrast enhancement in the subarachnoid space in TIA and TNA cases with HARM will be analyzed in detail.