Quantitative Corticospinal Tract Assessment in Acute Intracerebral Hemorrhage

Abstract

Intracerebral hemorrhage (ICH) prognostication during the acute phase is often subjective among physicians and often affects treatment decisions. The present study explores objective imaging parameters using quantitative corticospinal tract (CST) fiber reconstruction during the acute phase of ICH and correlates these parameters with functional outcome and patient recovery. We prospectively enrolled nonsurgical spontaneous supratentorial ICH patients and obtained an MRI scan on day 5 ± 1. Q-space diffeomorphic reconstruction was performed using DSI Studio, and quantitative anisotropy (QA) was calculated. The CST was reconstructed based on QA. The dichotomized modified Rankin Scale score on day 90 (favorable outcome = 0-2) and Barthel Index (favorable recovery = 100 on day 90 or improvement between discharge and day 90 > 60%) were assessed. Thirty-three patients, median age 72 years (interquartile range (IQR) 64-83), 21 female (64%), 21 (64%) with lobar hemorrhage, median ICH volume on admission 15.0 (IQR 7.0-27.4) mL, were included. Sixteen patients (48%) had a favorable outcome and 24 (73%) had a favorable recovery. The mean number of ipsilesional reconstructed CST fiber pathways was higher in patients with favorable outcomes (153 (standard deviation (SD) 103) vs. 60 (SD 39), p = 0.003) and predicted outcome after adjustment (Exp(B) = 1.016 (95% CI = 1.002-1.030)). QA in the ipsilesional posterior limb of the internal capsule showed a trend towards an association with favorable outcome (Exp(B) = 1.194 (95% CI = 0.991-1.439 (adjusted))). The total (ipsilesional + contralesional) number of reconstructed fiber pathways was associated with favorable recovery (Exp(B) = 1.025 (95% CI = 1.003-1.047 (adjusted))). Quantitative tractography parameters assessed in the acute phase of ICH may represent a promising predictor of long-term outcome and recovery. This might facilitate prognostic evaluation and organization of rehabilitation.

Keywords: All rehabilitation; DWI; Intracerebral hemorrhage; MRI; Outcome research.

Fig. 1

Tractography and reconstructed fiber pathways including an axial slice of the orientation density function (ODF). a, b Region of interest (ROI)/seeding region: green: posterior limb of internal capsule (PLIC), dark blue: cerebral peduncle (= ROI), red: corticospinal tract (= seeding region); region of avoidance: yellow: cerebellum. a Lateral view; b anterior-posterior view. c, d Reconstructed fiber pathways (corticospinal tract). c Anterior-posterior view including the seeding, the ROI, and the PLIC region on the right side; d lateral view

Fig. 2

Flowchart of included and excluded patients. MRI, magnetic resonance imaging

Fig. 3

Tract-based spatial statistics (TBSS). Decreased fractional anisotropy (FA) of the corticospinal tract (CST) of the affected hemisphere (left side (L); data sets of patients with right hemisphere hemorrhage have been flipped right-left). Red: CST-mask (JHU White Matter Tractography Atlas). Blue: clusters of voxels with decreased FA (p = 0.22, corrected). a Coronal view. b Axial view. Data superimposed on the MNI152 T1-brain mask for anatomical orientation

Fig. 4

Receiver operating characteristic curves for prediction of outcome and recovery. a Association of number of ipsilesional reconstructed fiber pathways (black line) and mean quantitative anisotropy (QA) of the ipsilesional posterior limb of the internal capsule (PLIC, dotted gray line) with favorable outcome. Receiver operating characteristic curves for the prediction of favorable day 90 outcome (mRS score 0–2). Gray line = reference line. Ipsilesional fiber number: AUC = 0.779 (95% CI = 0.597–0.962). Mean QA ipsilesional PLIC: AUC = 0.746 (95% CI = 0.574–0.919). b Association of number of total (ipsilesional + contralesional, gray dotted line) and ipsilesional (black line) reconstructed fiber pathways with favorable recovery (BI improvement between discharge and day 90 > 60% or day 90 BI = 100). Ipsilesional pathway number: AUC = 0.715 (95% CI = 0.537–0.893). Complete pathway number: AUC = 0.87 (95% CI = 0.744–0.997).