Related Experiment Video

Updated: Jun 8, 2026

A Metadata Extraction Approach for Clinical Case Reports to Enable Advanced Understanding of Biomedical Concepts
07:50

A Metadata Extraction Approach for Clinical Case Reports to Enable Advanced Understanding of Biomedical Concepts

Published on: September 20, 2018

16.2K

Analysis of Stroke Detection during the COVID-19 Pandemic Using Natural Language Processing of Radiology Reports

M D Li1, M Lang2, F Deng2

  • 1From the Departments of Radiology (M.D.L., M.L., F.D., K.C., K.B., S.R., W.A.M., J.K.-C.) mdli@mgh.harvard.edu.

AJNR. American Journal of Neuroradiology
|December 18, 2020
PubMed

Insights

The COVID-19 pandemic saw a 24% decrease in detected acute ischemic strokes via neuroimaging. However, a higher percentage of stroke-ordered imaging studies were positive, indicating a shift in stroke detection during the pandemic.

Area of Science:

  • Neurology
  • Radiology
  • Data Science

Background:

  • The COVID-19 pandemic has impacted healthcare, including neuroimaging volumes.
  • Quantifying changes in acute or subacute ischemic strokes during the pandemic is crucial.

Purpose of the Study:

  • To quantify the change in acute or subacute ischemic strokes detected by CT or MR imaging during the COVID-19 pandemic.
  • To utilize natural language processing (NLP) of radiology reports for this quantification.

Main Methods:

  • Retrospective analysis of 32,555 brain CT and MRI radiology reports from 2017-2020.
  • Development and validation of a random forest NLP classifier to detect acute or subacute ischemic stroke in free-text reports.
  • Evaluation of classifier performance using cross-validation and an external dataset.

Main Results:

  • An estimated 24% decrease in acute or subacute ischemic strokes detected via neuroimaging from March-April 2020 compared to 2017-2019 averages.
  • A significant increase in the proportion of stroke-ordered neuroimaging studies that detected acute or subacute ischemic strokes (16% to 21%, P=.01) in 2020.
  • NLP classifier achieved high accuracy (0.97) and F1 score (0.74) in cross-validation but performed worse on external data.

Conclusions:

  • Neuroimaging-detected acute or subacute ischemic stroke cases decreased during the COVID-19 pandemic.
  • A higher proportion of stroke-ordered studies were positive, suggesting a potential change in stroke diagnosis patterns.
  • NLP offers a valuable tool for tracking stroke numbers in epidemiologic studies, emphasizing the need for local classifier training.
Abstract

More Related Videos

Lung CT Segmentation to Identify Consolidations and Ground Glass Areas for Quantitative Assesment of SARS-CoV Pneumonia08:05

Lung CT Segmentation to Identify Consolidations and Ground Glass Areas for Quantitative Assesment of SARS-CoV Pneumonia

Published on: December 19, 2020

14.5K
Author Spotlight: Integrated Photoacoustic, Ultrasound, and Angiographic Tomography (PAUSAT) for NonInvasive Whole-Brain Imaging of Ischemic Stroke06:45

Author Spotlight: Integrated Photoacoustic, Ultrasound, and Angiographic Tomography (PAUSAT) for NonInvasive Whole-Brain Imaging of Ischemic Stroke

Published on: June 2, 2023

2.0K

Related Concept Videos

Stroke: Introduction and Types01:29

Stroke: Introduction and Types

A stroke is an acute neurological event caused by the sudden disruption of cerebral blood flow, leading to rapid loss of neuronal function. Neurons depend on continuous oxygen and glucose supply, so even brief interruptions can cause irreversible injury within minutes. Strokes are classified into ischemic and hemorrhagic types.Ischemic StrokeIschemic strokes are most common and occur due to arterial occlusion, depriving brain tissue of oxygen and nutrients. This leads to energy failure, ionic...
Ischemic Stroke l: Introduction01:15

Ischemic Stroke l: Introduction

Ischemic stroke is an acute cerebrovascular condition in which blood flow to a brain region is suddenly interrupted, leading to tissue infarction. Neurons depend on continuous oxygen and glucose supply, so even brief reductions in perfusion cause energy failure, ionic imbalance, and irreversible injury. Ischemic strokes are classified into thrombotic and embolic types based on their underlying mechanisms.Thrombotic MechanismsThrombotic stroke develops when a clot forms within a cerebral artery.
Hemorrhagic Stroke l: Introduction01:17

Hemorrhagic Stroke l: Introduction

A hemorrhagic stroke is an acute neurological event that occurs when a weakened cerebral blood vessel ruptures, allowing blood to accumulate within or around the brain. The sudden release of blood forms a focal hematoma that increases intracranial pressure, displaces neural tissue, and can obstruct cerebrospinal fluid pathways. These effects may be compounded by intraventricular extension of the hemorrhage, cerebral edema, or compression of adjacent structures, all of which contribute to...