Why dicom image displayed are inverse colour and lossy for output.

Why read dicom file but inverse . i' m try to stretch and Adjust but export file are lossy . (Tif)

origImg = dicomread(uigetfile('~/matlab/*.*', 'Select Dicom File'));

J=imadjust(origImg,stretchlim(origImg),[0 1]);

CExpo = adapthisteq(J,'Distribution','exponential','Alpha',3);

imwrite(CExpo,'finish.tif','Resolution',100);

Resoure and compare file : https://www.mediafire.com/?2xcwpt4khw3qh06

Thankyou for Help .