Longitudinal, Quantitative, Multimodal MRI Evaluation of Patients With Intracerebral Hemorrhage Over the First Year.

Muhammad E Haque,Octavio D Arevalo,Sean I Savitz,Xiurong Zhao,Maria A Parekh,Reshmi Gupta,Seth B Boren,Jaraslow Aronowski,Sarah George

doi:10.3389/fneur.2021.764718

Abstract

In most patients with intracerebral hemorrhage (ICH), the hematoma and perihematomal area decrease over the subsequent months but patients continue to exhibit neurological impairments. In this serial imaging study, we characterized microstructural and neurophysiological changes in the ICH-affected brain tissues and collected the National Institute of Health Stroke Scale (NIHSS) and modified Rankin Score (mRS), two clinical stroke scale scores. Twelve ICH patients were serially imaged on a 3T MRI at 1, 3, and 12 months (M) after injury. The hematoma and perihematomal volume masks were created and segmented using FLAIR imaging at 1 month which were applied to compute the susceptibilities (χ), fractional anisotropy (FA), mean diffusivity (MD), and cerebral blood flow (CBF) in the same tissues over time and in the matching contralesional tissues. At 3 M, there was a significant (p < 0.001) reduction in hematoma and perihematomal volumes. At 1 M, the χ, FA, and CBF were decreased in the perihematomal tissues as compared to the contralateral side, whereas MD increased. In the hematomal tissues, the χ increased whereas FA, MD, and CBF decreased as compared to the contralesional area at 1 M. Temporally, CBF in the hematoma and perihematomal tissues remained significantly (p < 0.05) lower compared with the contralesional areas whereas MD in the hematoma and χ in the perihematomal area increased. The NIHSS and mRS significantly correlated with hematoma and perihematomal volume but not with microstructural integrity. Our serial imaging studies provide new information on the long-term changes within the brain after ICH and our findings may have clinical significance that warrants future studies.

Highlights

Intracerebral hemorrhage (ICH) accounts for about 10–15% of all strokes and is associated with high mortality [1, 2]
Hematoma and perihematomal volumes are a strong prognostic tool for patients with acute ICH; we have a poor understanding of the long-term changes in the brain after the initial injury
The red blood cell lysis changes the heme iron oxidation state resulting in oxyhemoglobin changing to deoxyhemoglobin, which further converts to methemoglobin, which leads to hemosiderin

Summary

Introduction

Intracerebral hemorrhage (ICH) accounts for about 10–15% of all strokes and is associated with high mortality [1, 2]. In the acute phase of ICH, hematoma and perihematomal volume is routinely monitored using computed tomography (CT) in the hospitalized setting but the long-term effects on tissue physiology such as cerebral blood flow (CBF) and microstructural integrity have received little attention [15, 16]. Recent advancements in non-invasive quantitative magnetic resonance imaging enable us to serially probe the integrity and physiological status of the hematomal and perihematomal tissues over the long term. In this pilot study, we aimed to longitudinally monitor changes in the iron concentration, microstructural integrity, and cerebral perfusion within the perihematomal and hematomal tissues using quantitative susceptibility mapping (QSM), diffusion tensor imaging (DTI), and arterial spin labeling (ASL), respectively. Our study provides detailed findings on the dynamic changes in a number of novel endpoints as an initial approach to understanding and characterizing the long-term evolution of ICH within the first year after injury

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