Hospital-Based Prospective Registration of Acute Transient Ischemic Attack and Noncerebrovascular Events in Korea

Motor impairments in transient ischemic attack increase the odds of a positive diffusion-weighted imaging: A meta-analysis

BACKGROUND

Unilateral motor impairment is a key symptom used in the diagnosis of transient ischemic attack (TIA). Diffusion-weighted imaging (DWI) is a promising diagnostic tool for detecting ischemic lesions. While both motor impairments and DWI abnormalities are linked to the diagnosis of TIA, the association between these prognostic factors is not well understood.

OBJECTIVE

To examine the association between unilateral motor impairments and the odds of a positive DWI in TIA. Further, to determine whether the time between symptom onset and neuroimaging (delay to scan) influences the odds of a positive DWI.

METHODS

We used PRISMA guidelines to conduct a systematic search from 1989 to 2018. We included studies that reported number of individuals with/without unilateral motor symptoms and a positive/negative DWI.

RESULTS

Twenty-four studies from North America, Australia, Asia, and Europe were submitted to a meta-analysis. A pooled odds ratio of 1.80 (95% CI, 1.45-2.24, p = 0.00; I2 = 57.38) suggested that the odds of a positive DWI are greater in TIA individuals who experience motor symptoms as compared with those who experience no motor symptoms. Further, increasing the time delay to scan from the symptom onset (>2 days) did not influence the odds of a positive DWI as compared with an earlier scan (≤2 days).

CONCLUSIONS

The current meta-analysis provides cumulative evidence from 6710 individuals with TIA that the presence of motor symptoms increases the odds of a positive DWI by two-folds. These findings transform the clinical perception into evidence-based knowledge that motor impairments elevate the risk for brain tissue damage. Unilateral motor impairments in a cerebrovascular event should increase a physician's suspicion of detecting brain infarctions. These findings may influence the clinical management of TIA by generating faster response to motor impairments in TIA and accelerating referral to specialized stroke clinic.

Usefulness of hyperintense acute reperfusion marker sign in patients with transient neurologic symptom

It aimed to investigate the incidence and final diagnosis of hyperintense acute reperfusion marker (HARM) signs in patients initially suspected of having a transient ischemic attack (TIA).In retrospective manner, a series of consecutive series of patients who arrived at the emergency department and was initially assessed as TIA within 12 hours of symptom onset between July 2015 and December 2016 were enrolled. Conventional magnetic resonance imaging protocol including diffusion-weighted imaging (DWI) and pre- and post-contrast fluid attenuation inversion recovery imaging (FLAIR) was conducted to evaluate the ischemic lesion and prognosis. Through the review of medical records and imaging studies, their final diagnosis and its association with HARM signs on post-contrast FLAIR were investigated.A total of 174 subjects were enrolled (mean age, 64.0 ± 12.9 years old; male, 54.6%; DWI lesion, 17.8%). HARM signs were observed in 18 (10%) patients, and their final diagnoses were classified as true TIA (n = 11, 61%), seizure (2, 11%), posterior reversible encephalopathy (2, 11%), reversible cerebral vascular constriction (1, 6%) and unclassified encephalopathy (2, 11%). The co-occurrence of HARM and DWI lesions were observed in 7 subjects which were 6 subjects of true TIA (ischemic stroke) and 1 subject with RCVS related ischemic stroke.The observation of HARM sign would be helpful to confirm the ischemic insult and distinguish the other disease.

Role of Perfusion-Weighted Imaging in a Diffusion-Weighted-Imaging-Negative Transient Ischemic Attack

BACKGROUND AND PURPOSE

The absence of acute ischemic lesions in diffusion-weighted imaging (DWI) in transient ischemic attack (TIA) patients makes it difficult to diagnose the true vascular etiologies. Among patients with DWI-negative TIA, we investigated whether the presence of a perfusion-weighted imaging (PWI) abnormality implied a true vascular event by identifying new acute ischemic lesions in follow-up magnetic resonance imaging (MRI) in areas corresponding to the initial PWI abnormality.

METHODS

The included patients underwent DWI and PWI within 72 hours of TIA and also follow-up DWI at 3 days after the initial MRI. These patients had visited the emergency room between July 2009 and May 2015. Patients who demonstrated initial DWI lesions were excluded. The initial PWI abnormalities in the corresponding vascular territory were visually classified into three patterns: no abnormality, focal abnormality, and territorial abnormality.

RESULTS

No DWI lesions were evident in initial MRI in 345 of the 443 TIA patients. Follow-up DWI was applied to 87 of these 345 DWI-negative TIA patients. Initial PWI abnormalities were significantly associated with follow-up DWI abnormalities: 8 of 43 patients with no PWI abnormalities (18.6%) had new ischemic lesions, whereas 13 of 16 patients with focal perfusion abnormalities (81.2%) had new ischemic lesions in the areas of initial PWI abnormalities [odds ratio (OR)=15.1, 95% confidence interval (CI)=3.6-62.9], and 14 of 28 patients with territorial perfusion abnormalities (50%) had new lesions (OR=3.7, 95% CI=1.2-11.5).

CONCLUSIONS

PWI is useful in defining whether or not the transient neurological symptoms in DWI-negative TIA are true vascular events, and will help to improve the understanding of the pathomechanism of TIA.