Evidence map›Paper›PMID 25862260›Full record

ArticleNeuroImage2015

Validated automatic brain extraction of head CT images.

John Muschelli, Natalie L Ullman, W Andrew Mould, Paul Vespa, Daniel F Hanley, Ciprian M Crainiceanu

Open access · greenAbstract read
In one paragraph

Article in NeuroImage, 2015. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 44 papers.

0numbers the graph read from it
0cells of the map it votes in
44citing papers in PubMed
2.4field-weighted citation impact, top 7% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

44 citing papers in PubMed, 94 citations in OpenAlex.

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  14. Lesion-preserving unpaired image-to-image translation between MRI and CT from ischemic stroke patients.International journal of computer assisted radiology and surgery · 2023
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  18. [EJNMMI research · 2022
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4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

6 authors at 2 institutions in 1 country.

John MuschelliDepartment of Biostatistics, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA. Electronic address: jmusche1@jhu.edu.
Natalie L UllmanDepartment of Neurology, Division of Brain Injury Outcomes, Johns Hopkins Medical Institutions, Baltimore, MD, USA. Electronic address: nullman1@jhmi.edu.
W Andrew MouldDepartment of Neurology, Division of Brain Injury Outcomes, Johns Hopkins Medical Institutions, Baltimore, MD, USA. Electronic address: wmould1@jhmi.edu.
Paul VespaDepartment of Neurosurgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA. Electronic address: PVespa@mednet.ucla.edu.
Daniel F HanleyDepartment of Neurology, Division of Brain Injury Outcomes, Johns Hopkins Medical Institutions, Baltimore, MD, USA. Electronic address: dhanley@jhmi.edu.
Ciprian M CrainiceanuDepartment of Biostatistics, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA. Electronic address: ccrainic@jhsph.edu.
Johns Hopkins University · USUniversity of California, Los Angeles · US

Funding

MISTIE III_ Lead Grant_ Cluster Application for the Clinical Coordinating CenterU01NS080824 · NINDS · JOHNS HOPKINS UNIVERSITY · PI HANLEY, DANIEL F · 2013 to 2017
$23.2M
Clot Lysis: Evaluating Accelerated Resolution of IVH Phase III (CLEAR III)U01NS062851 · NINDS · JOHNS HOPKINS UNIVERSITY · PI HANLEY, DANIEL F · 2009 to 2013
$21.6M
EPIDEMIOLOGY AND BIOSTATISTICS OF AGINGT32AG000247 · NIA · JOHNS HOPKINS UNIVERSITY · PI Karen J. Bandeen-Roche · 1996 to 2026
$13.2M
ICH Removal: Minimally Invasive Surgery + rt-PAR01NS046309 · NINDS · JOHNS HOPKINS UNIVERSITY · PI HANLEY, DANIEL F · 2005 to 2011
$9.1M
Statistical Methods for Multilevel Multivariate Functional StudiesR01NS060910 · NINDS · JOHNS HOPKINS UNIVERSITY · PI Ciprian M Crainiceanu · 2009 to 2026
$8.3M
Statistical methods for large n and p problemsR01EB012547 · NIBIB · JOHNS HOPKINS UNIVERSITY · PI CAFFO, BRIAN SCOTT · 2010 to 2016
$2.1M
Statistical Methods for Mapping Human Brain DevelopmentR01MH095836 · NIMH · NEW YORK UNIVERSITY SCHOOL OF MEDICINE · PI REISS, PHILIP T · 2012 to 2016
$2.1M
Statistical methods for large and complex databases of ultra-high-dimensionalR01NS085211 · NINDS · UNIVERSITY OF PENNSYLVANIA · PI SHINOHARA, RUSSELL TAKESHI · 2013 to 2017
$1.8M
Statistical methods for biosignals with varying domainsR01HL123407 · NHLBI · JOHNS HOPKINS UNIVERSITY · PI CRAINICEANU, CIPRIAN M · 2014 to 2017
$1.6M
CLEAR IVH Phase III Planning GrantR34NS056638 · NINDS · JOHNS HOPKINS UNIVERSITY · PI HANLEY, DANIEL F · 2008 to 2008
$164k
NHLBI NIH HHS R01 HL123407NIA NIH HHS T32 AG000247NIA NIH HHS T32AG000247NIBIB NIH HHS R01 EB012547NIMH NIH HHS R01 MH095836NIMH NIH HHS R01MH095836NINDS NIH HHS R01 NS046309NINDS NIH HHS R01NS046309NINDS NIH HHS R01 NS060910NINDS NIH HHS R01NS060910NINDS NIH HHS R01 NS085211NINDS NIH HHS R01NS085211NINDS NIH HHS R34 NS056638NINDS NIH HHS U01 NS062851NINDS NIH HHS U01NS062851NINDS NIH HHS U01 NS080824NINDS NIH HHS U01NS080824
6 · The paper itself

Abstract

backgroundX-ray computed tomography (CT) imaging of the brain is commonly used in diagnostic settings. Although CT scans are primarily used in clinical practice, they are increasingly used in research. A fundamental processing step in brain imaging research is brain extraction - the process of separating the brain tissue from all other tissues. Methods for brain extraction have either been 1) validated but not fully automated, or 2) fully automated and informally proposed, but never formally validated.

aimTo systematically analyze and validate the performance of FSL's brain extraction tool (BET) on head CT images of patients with intracranial hemorrhage. This was done by comparing the manual gold standard with the results of several versions of automatic brain extraction and by estimating the reliability of automated segmentation of longitudinal scans. The effects of the choice of BET parameters and data smoothing is studied and reported.

methodsAll images were thresholded using a 0-100 Hounsfield unit (HU) range. In one variant of the pipeline, data were smoothed using a 3-dimensional Gaussian kernel (σ=1mm(3)) and re-thresholded to 0-100HU; in the other, data were not smoothed. BET was applied using 1 of 3 fractional intensity (FI) thresholds: 0.01, 0.1, or 0.35 and any holes in the brain mask were filled. For validation against a manual segmentation, 36 images from patients with intracranial hemorrhage were selected from 19 different centers from the MISTIE (Minimally Invasive Surgery plus recombinant-tissue plasminogen activator for Intracerebral Evacuation) stroke trial. Intracranial masks of the brain were manually created by one expert CT reader. The resulting brain tissue masks were quantitatively compared to the manual segmentations using sensitivity, specificity, accuracy, and the Dice Similarity Index (DSI). Brain extraction performance across smoothing and FI thresholds was compared using the Wilcoxon signed-rank test. The intracranial volume (ICV) of each scan was estimated by multiplying the number of voxels in the brain mask by the dimensions of each voxel for that scan. From this, we calculated the ICV ratio comparing manual and automated segmentation: ICVautomated/ICVmanual. To estimate the performance in a large number of scans, brain masks were generated from the 6 BET pipelines for 1095 longitudinal scans from 129 patients. Failure rates were estimated from visual inspection. ICV of each scan was estimated and an intraclass correlation (ICC) was estimated using a one-way ANOVA.

resultsSmoothing images improves brain extraction results using BET for all measures except specificity (all p<0.01, uncorrected), irrespective of the FI threshold. Using an FI of 0.01 or 0.1 performed better than 0.35. Thus, all reported results refer only to smoothed data using an FI of 0.01 or 0.1. Using an FI of 0.01 had a higher median sensitivity (0.9901) than an FI of 0.1 (0.9884, median difference: 0.0014, p<0.001), accuracy (0.9971 vs. 0.9971; median difference: 0.0001, p<0.001), and DSI (0.9895 vs. 0.9894; median difference: 0.0004, p<0.001) and lower specificity (0.9981 vs. 0.9982; median difference: -0.0001, p<0.001). These measures are all very high indicating that a range of FI values may produce visually indistinguishable brain extractions. Using smoothed data and an FI of 0.01, the mean (SD) ICV ratio was 1.002 (0.008); the mean being close to 1 indicates the ICV estimates are similar for automated and manual segmentation. In the 1095 longitudinal scans, this pipeline had a low failure rate (5.2%) and the ICC estimate was high (0.929, 95% CI: 0.91, 0.945) for successfully extracted brains.

conclusionBET performs well at brain extraction on thresholded, 1mm(3) smoothed CT images with an FI of 0.01 or 0.1. Smoothing before applying BET is an important step not previously discussed in the literature. Analysis code is provided.

Indexed as

BrainFemaleHeadHumansImage Processing, Computer-AssistedIntracranial HemorrhagesMaleMiddle AgedPattern Recognition, AutomatedReproducibility of ResultsTomography, X-Ray ComputedBrain extractionCTSkull strippingValidation

Identifiers

PMID25862260
PMCPMC4446187
OpenAlexW2036200541

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.