M7 L1- Digital subtraction

a 10 bit ADC will convert the analog signal into values between …

0-1023

what is digital subtraction angiography

computerized xray technique which the vasucular anatomy is visualized

what is the significance of DSA

used to detect blood clots, tumours, and other blockages of BV and ducts

What materials are needs in DSA

• contrast

• catheter

• guide wire

how is DSA done

• patient is laid down with electrodes to the chest for heart monitoring

• xray of the area is taken before contrast

• local anesthetic

• computer subtracts structures in the first picture when compared to the second picture, this leaves the BV

FDSA

fusion digital subtraction angiography

what is 3D FDSA

xray technique which combines 3D reconstruction of the BV

DRA

digital rotational angiography

when do we use 3D DRA

to visualize smaller anneurysms

what is interventional radiologists

uses imaging techniques for purposes of percutaneous, diagnostic, and therapeautic procedures

what is the significane of interventional radiologists

cancer treatment

needle biopsy

diagnostic test for breast and lung cancer

common IVR procedure

coronary angioplasty, opens blocked and narrowed vessels to place a balloon

materials needed for interventional radiography

stent, catheter, gastronomy tubes, blood clot filters, injecton of clot lysing agents

mask or scout image

taken before contrast is injected and it is what is subtracted in the image

2 types of temporal subtraction

mask mode and time interval difference mode

mask mode

before injection image and after is taken, compared, and then subtracted to only see vessels

time interval difference mode

each subtracted image is made form a different mask. there is a constant image acquisition rate. less motion artifcacts and less contrast. usually used in cardiac iamging to see shape of the heart

remasking

used when patient is moved, low contrast, to eliminate motion artifact or gas

re-registration of the mask other term

pixel shifting

what is pixel shifting

image is moved either horizontally or vertically to alighn two different images

when is pixel shifting used

motion artifact or unwanted informationn

when is roadmapping used

in DSA and is to demonstrate moving a catheter using iodinnated vessels as a map

what is land marking

using the orihinal mask on the subtracted image to provide anatomical landmarks