How can I add a column to a table / add a variable to a table?

Hi there, I want to add columns to a table which seems to be impossible by default. I created a workaround to do this but I wonder if there is a more straightforward way to do this? Thanks very much for your help!

Here's the code:

clear all, clc;

% the point of this script is to analyze region properties of a 
% binary image and write them to a file. However, more columns
% should be added before. 

% read coins sample and analyze region properties
imageName = 'coins.png';
I = im2bw(imread(imageName));
Cstruct = bwconncomp(I,8);
LC = labelmatrix(Cstruct);
ObjectInfo = regionprops(Cstruct, {'Area','Centroid'});

% Problem:
% it is not possible to add another variable to ObjInfo
% like ObjInfo.newCol = 1:length(ObjectInfo)

% create Table from Results
ObjTable = struct2table(ObjectInfo);

% I want to add columns to the table.
% But adding columns to a table is not possible.
% this is a dirty workaround

  ObjTable.rowID = cellstr(num2str(ObjTable.Area));
  ObjTable.sampleID = ObjTable.rowID;
  ObjTable.imgID = ObjTable.rowID; 
     a = ObjTable.rowID;
     b = ObjTable.sampleID;
     c = ObjTable.imgID;
     for m=1:numel(a) 
        a(m) = {m};
        b(m) = cellstr(imageName);
        c(m) = cellstr(imageName);
     end
     ObjTable.rowID = a;
     ObjTable.sampleID = b;
     ObjTable.imgID = c;
     clear a b c m;         
     % done

ObjTable