APT Weighted MRI as an Effective Imaging Protocol to Predict Clinical Outcome After Acute Ischemic Stroke

Damn it all, stop with this prediction crapola. Survivors want 100% recovery, they need rehab protocols, NOT THIS SHIT.  GET THERE! A great stroke association president would ream these researchers out for not following the stroke strategy that leads to 100% recovery.  Just because we have NO strategy is no reason to do these useless prediction ones.

APT Weighted MRI as an Effective Imaging Protocol to Predict Clinical Outcome After Acute Ischemic Stroke

Guisen Lin¹, Caiyu Zhuang¹, Zhiwei Shen¹, Gang Xiao², Yanzi Chen¹, Yuanyu Shen¹, Xiaodan Zong¹ and Renhua Wu^1,3*

• ¹Department of Medical Imaging, The Second Affiliated Hospital, Medical College of Shantou University, Shantou, China
• ²Department of Mathematics and Statistics, Hanshan Normal University, Chaozhou, China
• ³Provincial Key Laboratory of Medical Molecular Imaging, Shantou, China

To explore the capability of the amide-proton-transfer weighted (APTW) magnetic resonance imaging (MRI) in the evaluation of clinical neurological deficit at the time of hospitalization and assessment of long-term daily functional outcome for patients with acute ischemic stroke (AIS). We recruited 55 AIS patients with brain MRI acquired within 24–48 h of symptom onset and followed up with their 90-day modified Rankin Scale (mRS) score. APT weighted MRI was performed for all the study subjects to measure APTW signal quantitatively in the acute ischemic area (APTW_ipsi) and the contralateral side (APTW_cont). Change of the APT signal between the acute ischemic region and the contralateral side (ΔAPTW) was calculated. Maximum APTW signal (APTW_max) and minimal APTW signal (APTW_min) were also acquired to demonstrate APTW signals heterogeneity (APTW_max−min). In addition, all the patients were divided into 2 groups according to their 90-day mRS score (good prognosis group with mRS score <2 and poor prognosis group with mRS score ≥2). In the meantime, ΔAPTW of these groups was compared. We found that ΔAPTW was in good correlation with National Institutes of Health Stroke Scale (NIHSS) score (R² = 0.578, p < 0.001) and 90-day mRS score (R² = 0.55, p < 0.001). There was significant difference of ΔAPTW between patients with good prognosis and patients with poor prognosis. Plus, APTW_max−min was significantly different between two groups. These results suggested that APT weighted MRI could be used as an effective tool to assess the stroke severity and prognosis for patients with AIS, with APTW signal heterogeneity as a possible biomarker.

Introduction

As a promising contrast mechanism, chemical exchange saturation transfer (CEST) has become an important tool in the field of molecular imaging (1). Recently, APTW MRI, one form of CEST technology, has been increasingly applied in capturing tissue acidosis as a research tool based on its capability to detect pH and mobile proteins content (2). APTW MRI has been used to assess the severity of tissue acidification in hyperacute and acute stroke (3, 4). For all these pre-clinical researches, the induced stroke studies were carried out under highly controlled environment and the animals were scanned during early stage of stroke within hours. Under this circumstance, the APTW imaging was called pH-weighted imaging since pH was the major factor to affect the APTW signal intensity, accounting for more than 90% (5). Clinical assessment using APTW imaging is considered promising given its ability to characterize pH of the stroke area within hours from the symptom onset. The enthusiasm of applying the APTW imaging to patients with none hyperacute stroke (within hours from symptom onset) might be decreased given the fact that many factors can affect the APTW signal (5). However, a considerable proportion of patients with stroke have delay in presentation to the hospital (6, 7). Applying of APTW imaging might be clinically useful given the large number of patients with relatively delayed presentation to the hospital. In this study, we would like to testify the capability of APTW MRI as a tool to assess stroke severity as well as to predict clinical outcome of patient of acute ischemic stroke (AIS) with symptom onset between 24 and 48 h by measuring the change of APTW signal intensity.