Features of non-traumatic spinal cord infarction on MRI: Changes over time

Bo Ra Kim, Kyung Seok Park, Hyo Jin Kim, Jun Yup Kim, Bo Ram Kim, Eugene Lee, Joon Woo Lee

Abstract
Spinal cord infarction (SCI) is difficult to diagnosis using MRI findings. We aimed to suggest the optimal timing of MRI studies for diagnosing SCI.

Introduction
Spinal cord infarction (SCI) is a rare entity in comparison with cerebral infarction, accounting for only 1%–2% of all strokes [1–5]. Due to its rarity and nonspecific clinical manifestations, the diagnosis of SCI is challenging and more difficult in patients without risk factors such as prior aortic surgery [6,7]. Although treatment protocols for SCI are not well-established, early diagnosis and management are important to detect and correct the underlying causes, such as aortic dissection, as well as to prevent catastrophic neurological sequelae [6–10]. However, the diagnosis of SCI is challenging and depends on the identification of characteristic clinical features and compatible MRI findings and exclusion of alternative diagnoses.

Materials & Methods
This retrospective study was conducted in accordance with the tenets of the Declaration of Helsinki after obtaining approval from the institutional review board of Seoul National University Bundang Hospital (No.: B-2002-597-105). The requirement for informed consent was waived. To identify the study group, we performed searches using the diagnostic code for spinal cord infarction in our institutional electronic medical record system among cases recorded between January 2015 and August 2019. The neurologist (with 20 years of experience) subsequently reviewed the medical records of the patients to verify the diagnosis of SCI. Inclusion criteria were a final diagnosis of SCI with appropriate clinical (clear timeline and specificity of deficits, exclusion of alternative diagnoses, and/or the presence of causative events such as prior aortic surgery) and imaging data (MRI findings consistent with SCI and/or ruling out alterative diagnoses).

Results
For the study group, a total of 64 patients were identified from our institutional electronic medical record system. Of these, 30 patients were excluded on the basis of the following criteria: (a) clinical manifestations not consistent with SCI, such as trauma history and subacute or chronic symptoms (n = 16); (b) symptom onset not described in the medical records (n = 6); (c) spine MRI data not available (n = 5); and (d) alternative diagnosis confirmed on clinical evaluations, including cerebrospinal fluid (CSF) studies (n = 3; a 68-year-old man with spinal dural arteriovenous fistula, a 36-year-old woman with neuromyelitis optica, and an 8-year-old boy with acute transverse myelitis).

Discussion
Subgroup A included more cases of T2-weighted imaging (T2WI)-negative spinal cord infarction (SCIs) than T2WI-positive SCIs. The rates of T2WI-positivity increased with time; however, the confidence score of 5 (certainly yes) for diagnosing SCI on T2WI was the most common in subgroup D (4/27, 14.8%), in which assessments were performed between 24 and 72 hours after symptom onset. Among the 12 SCI patients in Table 4, two presented with T2WI-positivity on the follow-up MRI scan between 24 and 72 hours. In three of the 12 patients, the confidence scores decreased on follow-up MRI scans and were the highest between 24 and 72 hours. Therefore, SCI may present with equivocal findings on initial MRI scans, especially within 6 h after symptom onset. In these cases, follow-up MRI is recommended between 24 and 72 h, and the addition of a diffusion-weighted sequence is not necessary.

Conclusion
In cases with clinical suspicion of SCI showing negative or equivocal MRI findings within less than 6 h after symptom onset, follow-up MRI studies are helpful, especially when they are conducted between 24 and 72 h.

Citation: Kim BR, Park KS, Kim HJ, Kim JY, Kim BR, Lee E, et al. (2022) Features of non-traumatic spinal cord infarction on MRI: Changes over time. PLoS ONE 17(9): e0274821. https://doi.org/10.1371/journal.pone.0274821

Editor: Fabrizio Gelain, University of Milan-Bicocca, ITALY

Received: January 20, 2022; Accepted: September 2, 2022; Published: September 22, 2022

Copyright: © 2022 Kim et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: All relevant data are within the Supporting Information files.

Competing interests: The authors have declared that no competing interests exist.