DOI: 10.5061/dryad.dncjsxm55
title: Comparison of planar digital radiography and helical standing computed tomography for assessment of condylar stress fracture risk in Thoroughbred racehorses

description: Background: Catastrophic injury has a low incidence but leads to the death
 of many Thoroughbred racehorses. Objectives: To determine sensitivity,
 specificity, and reliability for condylar stress fracture risk assessment
 from fetlock digital radiographs (DR) and standing computed tomography
 (sCT). Study design: Controlled ex vivo experiment. Methods: A blinded set
 of thoracic limb fetlock DR and sCT images were prepared from 31
 Thoroughbreds. Four observers evaluated the condyles and parasagittal
 grooves (PSG) of the third metacarpal bone for the extent of dense bone
 and lucency/fissure and assigned a risk assessment grade for condylar
 stress fracture. Sensitivity and specificity for detection of subchondral
 structural changes in the condyles and PSG and for risk assessment for
 condylar stress fracture were determined by comparison with a reference.
 Agreement between observers and the reference assessment and reliability
 between observers were determined. Intra-observer repeatability was also
 assessed. Results: Sensitivity for detection of structural change was
 lower than specificity for both imaging methods and all observers. For
 horses with normal risk, observer assessment often agreed with the
 reference. Sensitivity for risk assessment was lower than specificity for
 all observers. For horses with a high risk of injury, observers generally
 underestimated risk. Diagnostic sensitivity of risk assessment was
 improved with sCT imaging, particularly for horses with elevated risk of
 injury. Assessment repeatability and reliability was better with sCT than
 DR. Main limitations: The ex vivo study design influenced DR image sets.
 Conclusions: Risk assessment through screening with diagnostic imaging is
 a promising approach to improve injury prevention in racing Thoroughbreds.
 Knowledge of sensitivity and specificity of fetlock lesion detection
 provides the critical guidance needed to improve screening programs for
 racehorses. We found improved detection of MC3 subchondral structural
 change and risk assessment for condylar stress fracture with sCT ex vivo.
description: Distal limb specimens were collected from catastrophically
 injured racing Thoroughbreds that were humanely euthanatized for reasons
 unrelated to this study and stored at -20C. Thoracic limb fetlock digital
 radiographs and standing computed tomography image sets were generated and
 blinded. Sensitivity and specificity for detection of structural changes
 in subchondral bone of the distal end of the third metacarpal bone as well
 as risk assessment for imminent injury from condylar stress fracture were
 estimated by four blinded observers. Reliability of estimations was also
 assessed.
description: DICOM file sets can be evaluated using any standard DICOM viewer
 software.
description: # Comparison of planar digital radiography and helical standing computed
 tomography for assessment of condylar stress fracture risk in Thoroughbred
 racehorses These files contain folders with blinded DICOM digital
 radiography image sets and DICOM standing computed tomography image sets
 from 31 racing Thoroughbreds. These image sets were used for blinded
 evaluation of structural changes in subchondral bone of the distal end of
 the third metacarpal bone and for risk assessment for imminent condylar
 stress fracture injury. These files enable any user of the data set to
 provide or undertake training in reading fetlock digital radiograph (DR)
 and standing computed tomography (sCT) image sets from Thoroughbred
 racehorses to improve clinical skills in detecting subchondral structural
 changes in the fetlock and predicting imminent risk of condylar stress
 fracture. ## Description of the data and file structure -DR (digital
 radiography) image sets, sCT (standing computed tomography) image sets,
 and post-digestion joint surface images are put in separate folders, with
 different patient numbers. The key for the blinded image sets is provided
 in the spreadsheet named "key_for_blinded_DR_and_CT.xlsx" in the
 root folder. -Each folder contains 35 DICOM folders for the 35 limbs in
 the study that 5 of them are the repeats. -Screenshot localizer images are
 also provided for each image set indicating the lateral aspect of the
 fetlock. -Grading form can be found in the root folder in the spreadsheet
 named "Image_review_forms.xlsx". There are 3 sheets in this form
 for assessment of DR, sCT, and postmortem images. Severity of increased
 subchondral bone density and focal lucency/fissure for lateral and medial
 condyles and parasagittal grooves are graded in the DR and sCT sheets.
 Subchondral plate thickness and focal lucency parasagittal area for
 lateral and medial parasagittal grooves are graded in the sCT sheet.
 Severity of bone lesion for lateral and medial condyles and parasagittal
 grooves are graded in the postmortem sheet. Overall risk assessment is
 graded in all 3 sheets. Detailed grading instructions/notes are provided
 in all 3 sheets. ## Sharing/Access information These data sets were used
 in the following published scientific study.
 ##
 Code/Software DICOM file sets can be accessed by any standard medical
 DICOM viewer software.