Quantitative Susceptibility Mapping for Staging Acute Cerebral Hemorrhages: Comparing the Conventional and Multiecho Complex Total Field Inversion magnetic resonance imaging MR Methods

Abstract

Background: The perceived acuity of intracerebral hemorrhage (ICH) impacts the management of patients, both within emergent and outpatient/urgent settings. Morphology enabled dipole inversion (MEDI) quantitative susceptibility imaging (QSM) has improved characterization of ICH acuity, despite outstanding limitations in distinguishing blood products.

Purpose/hypothesis: Using improved susceptibility quantification, novel postprocessing QSM method from multiecho complex total field inversion (mcTFI) may better discriminate between acute and subacute ICH, compared to MEDI.

Study type: Retrospective cohort study.

Subjects: A total of 121 subjects enrolled following positive computerized tomography (CT) findings for ICH. Subjects were grouped based on time between admission and MR imaging: hyperacute (<24 hours), acute (1-3 days), early subacute (3-7 days), and late subacute (7-18 days).

Field strength/sequence: A multiecho gradient echo sequence at 3.0 T was paired with clinical noncontrast CT imaging.

Assessment: A quantitative index (CT_index ) was derived based on relative intensities of blood on noncontrast CT. All images were co-registered, from which QSM parameters within the ICH area were assessed across groups, as well as the correlation with CT_index .

Statistical tests: Group differences were assessed using ANOVAs. Linear regressions between the CT_index , MEDI, and mcTFI measurements were used to assess their relationships. Statistical significance was set at P < 0.05.

Results: A total of 21 hyperacute, 72 acute, 21 early subacute, and 7 late-subacute patients were included in this analysis. Significant changes in blood susceptibility were found over time for the MEDI and mcTFI, although mcTFI better differentiated the hyperacute/acute from subacute stages. CT_index values within the ICH were more strongly correlated with mcTFI QSM (r = 0.727) than MEDI (r = 0.412) QSM.

Data conclusion: McTFI susceptibility estimation demonstrated better correlation with ICH acuity as suggested by CT, providing an improved method to assess acuity of intracranial blood products in clinical settings to identify cases that may require acute intervention.

Level of evidence: 4 TECHNICAL EFFICACY STAGE: 2.

Keywords: computed tomography; hemorrhagic staging; intracranial bleeds; quantitative susceptibility mapping; total field inversion.