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R8218/ShoulderCase/Acromion.m
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Acromion.m
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classdef Acromion < handle
%ACROMION Properties and methods associted to the acromion.
% Detailed explanation goes here
properties
AI % Acromion Inddex (doi:10.2106/JBJS.D.03042)
CSA % Critital Shoulder Angle (doi:10.1302/0301-620X.95B7.31028)
PSA % Posterior Slope Angle (10.1016/S1058-2746(05)80036-9)
PSL % Length of segment beteeen AA and AC
AAA % Angulus Angle Angle (Angle between AA-origin and PA axis)
AAL % Length of segment between origine and AA
AAx % PA (x) position of AA
AAy % IS (y) position of AA
AAz % ML (z) position of AA
ACx % PA (x) position of AC
ACy % IS (y) position of AC
ACz % ML (z) position of AC
comment
end
properties (Hidden = true)
SCase
scapula
end
methods (Access = ?Scapula) % Only Scapula is allowed to construct a Acromion
function obj = Acromion(SCase)
%ACROMION Construct an instance of this class
% Instance of the acromion objet set all properties to zero;
obj.AI = [];
obj.CSA = [];
obj.PSA = [];
obj.PSL = [];
obj.AAA = [];
obj.AAL = [];
obj.AAx = [];
obj.AAy = [];
obj.AAz = [];
obj.ACx = [];
obj.ACy = [];
obj.ACz = [];
obj.comment = '';
obj.SCase = SCase;
obj.scapula = [];
end
end
methods
function outputArg = morphology(obj)
%MORPHOLOGY Performs morphology analysis of the acromion.
% It caluculates acromion index (AI), critical shoulder angle
% (CSA), and posterior slope (PS). The glenoid and scapula
% surface are re-oriented (rotated and translated) in the
% scapular coordinate system. For AI nd CSA, glenoid and
% scapula points are projected in the scapular plane, which is
% [1 0 0] after the re-orientation.
% TODO:
% Might be removed anatomy for concistency
SCase = obj.SCase;
%% Get local coordinate system from parent scapula
origin = obj.scapula.coordSys.origin;
xAxis = obj.scapula.coordSys.PA;
yAxis = obj.scapula.coordSys.IS;
zAxis = obj.scapula.coordSys.ML;
% Rotation matrix to align to scapula coordinate system
R = [xAxis' yAxis', zAxis'];
%% Scapula, glenoid, and scapula landmarks in scapula coordinate system
% Scapula surface alignment is done in next section, for the
% caulation of AI, because of mix between auto, manual and no
% segmentation. This should be corrected when there will be two
% scapula object per shoulder (manual and auto).
% Glenoid surface in scapular coordinate system
glenSurf = (obj.scapula.glenoid.surface.points - origin) * R;
% Glenoid center in scapular coordinate system
glenCenter = (obj.scapula.glenoid.center - origin) * R;
% Scapula landmarks in scapular coordinate system
AC = (obj.scapula.acromioClavicular - origin) * R; % Acromio-clavicular landmark
AA = (obj.scapula.angulusAcromialis - origin) * R; % Angulus acromialis landmark
obj.ACx = AC(1);
obj.ACy = AC(2);
obj.ACz = AC(3);
obj.AAx = AA(1);
obj.AAy = AA(2);
obj.AAz = AA(3);
%% Acromion Index (AI)
% Adapted by AT (2018-07-18) from Valerie Mafroy Camine (2017)
% AI = GA/GH, where:
% GA: GlenoAcromial distance in scapula plane = distance from
% AL to glenoid principal axis
% GH: GlenoHumeral distance = 2*HHRadius, humeral head diameter (radius*2)
% AL: most lateral point of the acromion
% Get all required data, aligned in scapular plane, and
% project in scapular plane.
ScapPlaneNormal = [1 0 0]; % Normal of the scapular plane in the scapular coordinate system
PlaneMean = [0 0 0]; % Origin of scapular system in scapular coordinate system
% Project glenoid surface in scapular plane
glenSurf = project2Plane(glenSurf,ScapPlaneNormal,PlaneMean,size(glenSurf,1));
% Project glenoid center in scapular plane
glenCenter = project2Plane(glenCenter,ScapPlaneNormal,PlaneMean,size(glenCenter,1));
% If scapula is segmented, get AL from most lateral part of the
% scapula, otherwise use acromio-clavicular landmark
% Get segmentation propertiy from parent scapula
segmentedScapula = obj.scapula.segmentation;
segmentedScapula = strcmp(segmentedScapula,'A') || strcmp(segmentedScapula,'M');
if segmentedScapula == 1
% Rotate scapula surface to align the scapular plane with
% the YZ plane, and then take the max Z (lateral) point
% Transform scapula surface to scapula coordinate system
scapSurf = obj.scapula.surface.points;
scapSurf = (scapSurf - origin) * R;
scapSurf = project2Plane(scapSurf,ScapPlaneNormal,PlaneMean,size(scapSurf,1));
% Take the most lateral point of the scapula, assuming that
% this point is the most lateral point of the acromion
[~,ALpositionInScapula] = max(scapSurf(:,3));
AL = scapSurf(ALpositionInScapula,:);
else
% No scapula points, we approximate AL with the acromioClavicular
% landmark, in the scapula coordinate system
AL = AC; % Acroomio-clavicalar scapula landmark
AL = project2Plane(AL,ScapPlaneNormal,PlaneMean,size(AL,1));
end
% Find glenoid principal axis with most superior and most inferior projected
% glenoid points
% AT: This method is not ideal. PCA would be better. It is also
% used below by the CSA
glenPrinAxis = [...
glenSurf(glenSurf(:,2) == min(glenSurf(:,2)),:) ;...
glenSurf(glenSurf(:,2) == max(glenSurf(:,2)),:)...
];
% Compute GA (distance from AL to glenoid principal axis)
% Most inferior point of the scapula surface
IG = glenPrinAxis(1, :);
% Most superior point of the scapula surface
SG = glenPrinAxis(2, :);
GA = norm(cross(SG - IG, AL - IG))/norm(SG - IG);
% GH (Humeral head diameter)
% get humeral head radius from associated humerus
GH = 2 * SCase.shoulder.humerus.radius;
% Acromion index
if ~isempty(GH)
obj.AI = GA/GH;
end
%% Critical Shoulder Angle (CSA)
% Adapted by AT (2018-07-18) from Bharath Narayanan (2018)
% [radCSA, degCSA] = computeCSA(GlenoidPtsinScapulaPlane, ALinScapulaPlane);
% Vectors connecting IG to SG, and IG to AL
IGSG = SG - IG;
IGAL = AL - IG;
CSA = vrrotvec(IGSG,IGAL);
CSA = CSA(4);
CSA = rad2deg(CSA);
obj.CSA = CSA;
%% Posterior Slope Angle and length (PSA & PSL)
% By AT (2018-08-10)
% Project AA & AC in PA-IS plane
AAxy = [AA(1:2) 0]; % Juste take x and y component
ACxy = [AC(1:2) 0]; % Juste take x and y component
PSv = ACxy - AAxy; % Posterior slope vector
ISv = [1 0 0]; % IS axis
PSA = vrrotvec(PSv, ISv);
PSA = PSA(4);
PSA = rad2deg(PSA);
PSL = norm(PSv);
obj.PSA = PSA;
obj.PSL = PSL;
%% Acromial Angle Angle and length (AAA & AAL)
% By AT (2018-09-13)
% Vector between scapular origin and AA in the plane PA-IS
AAv = [AA(1:2) 0];
% Angle between AAvect and PA axis
PAv = [1 0 0]; % PS axis
AAA = vrrotvec(AAv, PAv);
AAA = AAA(4);
AAA = rad2deg(AAA);
AAA = 180 - AAA;
AAL = norm(AAv);
obj.AAA = AAA;
obj.AAL = AAL;
%% We might save an image of AI, CSA, PS
outputArg = 1;
end
end
end
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