Predicting the Onset of Ischemic Stroke With Fast High‐Resolution 3D MR Spectroscopic Imaging

Abstract

Background Neurometabolite concentrations provide a direct index of infarction progression in stroke. However, their relationship with stroke onset time remains unclear. Purpose To assess the temporal dynamics of N‐acetylaspartate (NAA), creatine, choline, and lactate and estimate their value in predicting early (<6 hours) vs. late (6–24 hours) hyperacute stroke groups. Study Type Cross‐sectional cohort. Population A total of 73 ischemic stroke patients scanned at 1.8–302.5 hours after symptom onset, including 25 patients with follow‐up scans. Field Strength/Sequence A 3 T/magnetization‐prepared rapid acquisition gradient echo sequence for anatomical imaging, diffusion‐weighted imaging and fluid‐attenuated inversion recovery imaging for lesion delineation, and 3D MR spectroscopic imaging (MRSI) for neurometabolic mapping. Assessment Patients were divided into hyperacute (0–24 hours), acute (24 hours to 1 week), and subacute (1–2 weeks) groups, and into early (<6 hours) and late (6–24 hours) hyperacute groups. Bayesian logistic regression was used to compare classification performance between early and late hyperacute groups by using different combinations of neurometabolites as inputs. Statistical Tests Linear mixed effects modeling was applied for group‐wise comparisons between NAA, creatine, choline, and lactate. Pearson's correlation analysis was used for neurometabolites vs. time. P < 0.05 was considered statistically significant. Results Lesional NAA and creatine were significantly lower in subacute than in acute stroke. The main effects of time were shown on NAA (F = 14.321) and creatine (F = 12.261). NAA was significantly lower in late than early hyperacute patients, and was inversely related to time from symptom onset across both groups (r = −0.440). The decrease of NAA and increase of lactate were correlated with lesion volume (NAA: r = −0.472; lactate: r = 0.366) in hyperacute stroke. Discrimination was improved by combining NAA, creatine, and choline signals (area under the curve [AUC] = 0.90). Data Conclusion High‐resolution 3D MRSI effectively assessed the neurometabolite changes and discriminated early and late hyperacute stroke lesions. Evidence Level 1. Technical Efficacy Stage 2.

Incidental diagnosis of an acute cerebrovascular event on 99mTc- HMDP bone scintigraphy performed due to suspicion of amyloidosis

“…Se han determinado varias etapas, cada una con diferentes manifestaciones imagenológicas: hiperaguda temprana (0 a 6 horas), hiperaguda tardía (6 a 24 horas), aguda (24 horas a 1 semana), subaguda (1 a 2 semanas), crónica (más de 2 semanas) (5).…”

Accelerated 3D metabolite T1 mapping of the brain using variable‐flip‐angle SPICE

“…In data processing, SPICE leverages a union‐of‐subspaces model to address the problems of water and lipid removal and metabolite reconstruction from sparse and noisy data. With these advances, SPICE can provide 3D metabolite mapping in several clinical applications, including stroke, 23–25 tumor, 26 Alzheimer's disease, 27 and epilepsy 28 . However, the current SPICE method lacks metabolite T 1 mapping capability; thus, the resulting metabolite signals carry strong T 1 ‐weighting effects due to short‐TR (160 ms) acquisition.…”

Editorial for “Predicting the Onset of Ischemic Stroke With Fast High‐Resolution 3D MR Spectroscopic Imaging”

“…8 In this issue of JMRI, Lin et al applied 3D magnetic spectroscopic imaging (MRSI) capturing temporal metabolic changes as a marker to predict the onset time of stroke, which is crucial to identify thrombolytic treatment window. 9 Qualitatively, an experienced neuroradiologist can assess the age of a stroke, but in most instances, the decision to administer tPA is on bedside family members or patients, which is often not accurate. Using SPICE (SPectroscopic Imaging by exploiting spatiospectral Correlation) protocol, the author overcomes several in vivo MRS limitations such as long acquisition time, limited brain coverage, larger voxel size, and partial volume effect.…”

“…In this issue of JMRI , Lin et al applied 3D magnetic spectroscopic imaging (MRSI) capturing temporal metabolic changes as a marker to predict the onset time of stroke, which is crucial to identify thrombolytic treatment window 9 . Qualitatively, an experienced neuroradiologist can assess the age of a stroke, but in most instances, the decision to administer tPA is on bedside family members or patients, which is often not accurate.…”