Brain extraction for fixed tissue banking: a technical report.
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The authors' code
R · 208 lines · 8 KB · MIT
- # Load required libraries
- library(ggplot2)
- library(readr)
- library(dplyr)
- library(tidyr)
- cbPalette <- c("#999999", "#E69F00", "#56B4E9", "#009E73", "#F0E442", "#0072B2", "#D55E00", "#CC79A7")
- # Load data
- df <- read_tsv("Brain Extraction Data and Stats - Raw Data Updated Anonymized.tsv")
- # Clean up column names
- names(df)[names(df) == "Case ID"] <- "Case_ID"
- names(df)[names(df) == "Perfusion?"] <- "Perfusion"
- names(df)[names(df) == "PMI (hours)"] <- "PMI_hours"
- names(df)[names(df) == "Soft Tissue Removal Time (minutes)"] <- "Soft_Tissue_Time"
- names(df)[names(df) == "Craniectomy Time (minutes)"] <- "Craniectomy_Time"
- names(df)[names(df) == "Dura Removal Time (minutes)"] <- "Dura_Time"
- names(df)[names(df) == "Brain Isolation Time (minutes)"] <- "Brain_Isolation_Time"
- names(df)[names(df) == "Total Removal Time (minutes)"] <- "Total_Time"
- names(df)[names(df) == "Traction Injury Count"] <- "Traction_Injuries"
- names(df)[names(df) == "Laceration Count"] <- "Lacerations"
- names(df)[names(df) == "Total Injuries"] <- "Total_Injuries"
- names(df)[names(df) == "Injury Level"] <- "Injury_Level"
- names(df)[names(df) == "PMI Length"] <- "PMI_Length"
- # Check it loaded correctly
- head(df)
- names(df)
- # ===== FIGURE Procedure Time Distribution =====
- # Reshape the data
- timing_long <- df %>%
- select(Case_ID, Soft_Tissue_Time, Craniectomy_Time, Dura_Time, Brain_Isolation_Time) %>%
- pivot_longer(cols = c(Soft_Tissue_Time, Craniectomy_Time, Dura_Time, Brain_Isolation_Time),
- names_to = "Step",
- values_to = "Time") %>%
- mutate(Step = case_when(
- Step == "Soft_Tissue_Time" ~ "Soft Tissue",
- Step == "Craniectomy_Time" ~ "Craniectomy",
- Step == "Dura_Time" ~ "Dura Removal",
- Step == "Brain_Isolation_Time" ~ "Brain Isolation"
- )) %>%
- mutate(Step = factor(Step, levels = c("Soft Tissue", "Craniectomy", "Dura Removal", "Brain Isolation"))) %>%
- filter(Time <= 75)
- # Create the plot
- ggplot(timing_long, aes(x = Step, y = Time, fill = Step, color = Step)) +
- geom_violin(alpha = 0.7) +
- geom_jitter(width = 0.2, alpha = 0.5) +
- stat_summary(fun = mean, geom = "crossbar", width = 0.5, color = "#FF7F7F", linewidth = 0.3) +
- labs(
- title = "Time Distribution by Procedure Step",
- x = "Procedure Step",
- y = "Time (minutes)"
- ) +
- scale_fill_manual(values = cbPalette[1:4]) +
- scale_color_manual(values = cbPalette[1:4]) +
- theme_bw() +
- theme(
- plot.title = element_text(face = "bold", hjust = 0.5),
- axis.text.x = element_text(angle = 45, hjust = 1, size = 10),
- axis.text.y = element_text(size = 11),
- legend.position = "none"
- )
- ggplot(df, aes(x = PMI_hours, y = Total_Time)) +
- geom_point(alpha = 0.6, size = 2, color = "darkblue") +
- geom_smooth(method = "lm", se = TRUE, color = "#FF7F7F", linewidth = 1) +
- labs(
- x = "Post-Mortem Interval (Hours)",
- y = "Total Removal Time (Minutes)"
- ) +
- scale_x_log10() + # This creates the log scale
- theme_bw()
- ## Learning curve analysis
- # Filter out Tech 4 (who had significant experience), keep techs with 10+ cases, and create sequential case numbers
- df_sequential <- df %>%
- filter(Tech != "Tech 4") %>%
- group_by(Tech) %>%
- filter(n() >= 10) %>%
- arrange(Tech, Case_ID) %>%
- mutate(Case_Number = row_number()) %>%
- ungroup() %>%
- # Assign anonymous tech numbers
- mutate(Tech_Number = paste0("Tech ", as.numeric(factor(Tech, levels = unique(Tech)))))
- # Plot learning curves - cleaner version with facets
- ggplot(df_sequential, aes(x = Case_Number, y = Total_Time)) +
- geom_point(alpha = 0.5, size = 1.5) +
- geom_smooth(method = "loess", se = TRUE, color = "#0072B2", fill = "#0072B2", alpha = 0.2) +
- facet_wrap(~Tech_Number, scales = "free_x") +
- labs(
- x = "Sequential Case Number",
- y = "Total Removal Time (minutes)"
- ) +
- scale_x_continuous(limits = c(0, NA), expand = expansion(mult = c(0, 0.05))) +
- theme_minimal() +
- theme(
- panel.spacing = unit(1.5, "lines"),
- strip.text = element_text(face = "bold")
- )
- # Sample size
- cat("Total cases: n =", nrow(df), "\n\n")
- # Craniectomy Time
- cat("CRANIECTOMY TIME:\n")
- cat(" Mean:", round(mean(df$Craniectomy_Time), 1), "minutes\n")
- cat(" SD:", round(sd(df$Craniectomy_Time), 1), "minutes\n")
- cat(" Range:", min(df$Craniectomy_Time), "-", max(df$Craniectomy_Time), "minutes\n")
- # Soft Tissue Removal Time
- cat("SOFT TISSUE REMOVAL TIME:\n")
- cat(" Mean:", round(mean(df$Soft_Tissue_Time), 1), "minutes\n")
- cat(" SD:", round(sd(df$Soft_Tissue_Time), 1), "minutes\n")
- cat(" Range:", min(df$Soft_Tissue_Time), "-", max(df$Soft_Tissue_Time), "minutes\n\n")
- # Dura Removal Time
- cat("DURA REMOVAL TIME:\n")
- cat(" Mean:", round(mean(df$Dura_Time), 1), "minutes\n")
- cat(" SD:", round(sd(df$Dura_Time), 1), "minutes\n")
- cat(" Range:", min(df$Dura_Time), "-", max(df$Dura_Time), "minutes\n\n")
- # Brain Isolation Time
- cat("BRAIN ISOLATION TIME:\n")
- cat(" Mean:", round(mean(df$Brain_Isolation_Time), 1), "minutes\n")
- cat(" SD:", round(sd(df$Brain_Isolation_Time), 1), "minutes\n")
- cat(" Range:", min(df$Brain_Isolation_Time), "-", max(df$Brain_Isolation_Time), "minutes\n\n")
- # Total Procedure Time
- cat("TOTAL PROCEDURE TIME:\n")
- cat(" Mean:", round(mean(df$Total_Time), 1), "minutes\n")
- cat(" SD:", round(sd(df$Total_Time), 1), "minutes\n")
- cat(" Range:", min(df$Total_Time), "-", max(df$Total_Time), "minutes\n\n")
- # PMI statistics
- cat("PMI STATISTICS:\n")
- cat(" Mean:", round(mean(df$PMI_hours), 1), "hours\n")
- cat(" Median:", round(median(df$PMI_hours), 1), "hours\n")
- cat(" Range:", round(min(df$PMI_hours), 1), "-", round(max(df$PMI_hours), 1), "hours\n\n")
- cor.test(df$Total_Time, df$PMI_hours, method = "spearman")
- cat("=== TISSUE DAMAGE STATISTICS ===\n\n")
- # Lacerations
- cat("LACERATIONS:\n")
- cat(" Mean:", round(mean(df$Lacerations), 2), "\n")
- cat(" SD:", round(sd(df$Lacerations), 2), "\n")
- cat(" Range:", min(df$Lacerations), "-", max(df$Lacerations), "\n")
- cat(" Cases with 1+:", sum(df$Lacerations > 0),
- "(", round(100*sum(df$Lacerations > 0)/nrow(df), 1), "%)\n")
- # Traction Injuries
- cat("TRACTION INJURIES:\n")
- cat(" Mean:", round(mean(df$Traction_Injuries), 2), "\n")
- cat(" SD:", round(sd(df$Traction_Injuries), 2), "\n")
- cat(" Range:", min(df$Traction_Injuries), "-", max(df$Traction_Injuries), "\n")
- cat(" Cases with 1+:", sum(df$Traction_Injuries >= 1),
- "(", round(100*sum(df$Traction_Injuries >= 1)/nrow(df), 1), "%)\n")
- # ===== TECHNICIAN SUMMARY TABLE =====
- cat("=== TECHNICIAN COMPARISON: TIME AND LACERATIONS ===\n\n")
- tech_summary <- df %>%
- group_by(Tech) %>%
- summarise(
- N_Cases = n(),
- Time_Mean = mean(Total_Time),
- Time_Median = median(Total_Time),
- Time_SD = sd(Total_Time),
- Lac_Mean = mean(Lacerations),
- Lac_Total = sum(Lacerations),
- Trac_Mean = mean(Traction_Injuries),
- TotInj_Mean = mean(Total_Injuries),
- PMI_Median = median(PMI_hours)
- ) %>%
- arrange(desc(N_Cases))
- print(tech_summary, n = Inf)
- # ===== STATISTICAL TESTS =====
- cat("\n\n=== STATISTICAL TESTS ===\n\n")
- # Filter to technicians with >= 5 cases
- techs_5plus <- tech_summary %>% filter(N_Cases >= 5) %>% pull(Tech)
- df_filtered <- df %>% filter(Tech %in% techs_5plus)
- # Kruskal-Wallis test for lacerations across technicians
- kw_lac <- kruskal.test(Lacerations ~ Tech, data = df_filtered)
- cat("Kruskal-Wallis test for lacerations across technicians (n>=5):\n")
- cat(sprintf(" H = %.2f, p = %.4f\n", kw_lac$statistic, kw_lac$p.value))
- # Kruskal-Wallis test for total time across technicians
- kw_time <- kruskal.test(Total_Time ~ Tech, data = df_filtered)
- cat("\nKruskal-Wallis test for total time across technicians (n>=5):\n")
- cat(sprintf(" H = %.2f, p = %.4f\n", kw_time$statistic, kw_time$p.value))
- # ===== TECH 4 =====
- tech4 <- df %>% filter(Tech == "Tech 4")
- cat(sprintf("Tech 4 (n=%d):\n", nrow(tech4)))
- cat(sprintf(" Time: mean=%.1f, median=%.1f\n", mean(tech4$Total_Time), median(tech4$Total_Time)))
- cat(sprintf(" Lacerations: mean=%.2f, total=%d\n", mean(tech4$Lacerations), sum(tech4$Lacerations)))
figures_code.R at commit 937e25d, under MIT · at the source
Overview
- Apex Neuroscience, Salem, Oregon, USA
- Friedman Brain Institute, Departments of Pathology, Neuroscience, and Artificial Intelligence & Human Health, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Neuropathology Brain Bank & Research Core and Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, New York, USA
Abstract
Brain banking enables the study of human neural tissue and is essential for research on disease, physiology, and neuroanatomy. An essential step for whole brain studies is the extraction of the brain from the skull. Yet detailed technical descriptions of brain removal are rare, perhaps contributing to the artifactual tissue disruption sometimes observed as a result of the procedure. Here, we describe a method for whole brain extraction that could be implemented in the context of a whole-body donation, focused on the use case of fixed tissue banking. The method involves a sequential craniectomy that uses both circumferential and midline sagittal cuts, followed by a posterior approach to cutting the dura. We report the application of this protocol across n = 105 human whole-body donors. We document the time required for each procedural step and the frequency of craniectomy artifacts and skull edge artifacts at the brain surface. When the brain tissue is particularly soft, we also describe the potential use of in situ immersion fixation to increase tissue stiffness before removal, finding however that this also slows the diffusion of chemicals into the interior of the brain. Our experience suggests that the effectiveness of brain extraction can be improved via procedural optimizations. Technicians can become comfortable with the method after approximately 5–10 cases. We anticipate that improving brain extraction quality may support downstream work in the development of diagnostics and treatments for neurological and psychiatric disease.
Reproduced under the paper's license (CC BY), from the paper cited above.
Repository
Its files are read in the Code ↔ Paper reader above.
andymckenzie/Brain_extraction
937e25d1c7fe9618be2d342d1994bae33bbf8eef, 2 March 2026Availability: 1 check, the latest on 28 September 2026: the link answers
- 28 September 2026: the link answers
2 files
- figures_code.R, R, 208 lines
- LICENSE, License, 21 lines
The paper's code and data availability statement is in the Data section.
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Data
Datasets cited
- zenodo.org/
communities/ , at zenodo.org; found in “Data availability”brainextraction
Data availability
Whole slide image data can be accessed in a public repository on Zenodo, available here: https://
Reproduced under the paper's license (CC BY), from the paper cited above.
Versions
The history of this record: each version stored by the harvester or made by a correction of its authors or of the maintainers of its code, and what changed in its facts. The texts of the paper (its abstract, its availability statements) are not part of it; versions that changed only those are not listed.
Version 1, 28 September 2026: the first record
Recorded: type, language, journal, volume, pages, dates, 12 authors, 5 keywords, 32 references.
Cite
This paper
Wolf, M., Beck, A., Paredes, L., Darcy, S., Parra, A., Taylor, G. A., Garrood, M., Thorn, E. L., Sanctis, C. D., Crary, J. F., Farrell, K., & McKenzie, A. T. (2026). Brain extraction for fixed tissue banking: a technical report. Free neuropathology, 7, 11. https://
BibTeX
@article{wolf2026brain,
author = {Wolf, Mads and Beck, Autumn and Paredes, Laura and Darcy, Sarah and Parra, Alexander and Taylor, Gabriel A. and Garrood, Macy and Thorn, Emma L. and Sanctis, Claudia De and Crary, John F. and Farrell, Kurt and McKenzie, Andrew T.},
title = {{Brain extraction for fixed tissue banking: a technical report}},
journal = {Free neuropathology},
year = {2026},
month = may,
volume = {7},
pages = {11},
publisher = {Free Neuropathology General Assembly},
issn = {2699-4445},
doi = {10.17879/
url = {https://
pmid = {42222515},
pmcid = {PMC13217454}
}
RIS
TY - JOUR
AU - Wolf, Mads
AU - Beck, Autumn
AU - Paredes, Laura
AU - Darcy, Sarah
AU - Parra, Alexander
AU - Taylor, Gabriel A.
AU - Garrood, Macy
AU - Thorn, Emma L.
AU - Sanctis, Claudia De
AU - Crary, John F.
AU - Farrell, Kurt
AU - McKenzie, Andrew T.
TI - Brain extraction for fixed tissue banking: a technical report
T2 - Free neuropathology
J2 - Free Neuropathol
PY - 2026
DA - 2026/
VL - 7
SP - 11
SN - 2699-4445
PB - Free Neuropathology General Assembly
DO - 10.17879/
UR - https://
LA - en
ER -
CSL-JSON
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"author": [
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"family": "Wolf",
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