ch. 26 interventional radiology

IR has __ than conventional fluoroscopy

faster image acquisition

postprocessing of IR enhances

image contrast

matrix size of IR

1024 × 1024 (1000 line system)

spatial resolution determined by

image matrix and size of image receptor (limited by pixels)

under couch tube operates in

radiographic mode

tube current is __ vs __ of image intensified fluoro

hundreds of mA

<5 mA

digital fluoroscopy uses __ technology

pulse progressive

image acquisition rates of

1-10 per second

__ instead II, times can be varied to reduce patient dose

flat panel

time for x-ray tube to be switched on and reach selected levels of kVp and mA

interrogation time

time for x-ray tube to be switched off

extinction time

fraction of time the tube is energized, reduces patient dose

duty cycle

digital fluoro uses __ generators with interrogation and extinction time of less than __

high frequency

1 ms

sensitive component of CCD

layer of crystalline silicon

when silicon illuminates

electric charge is generated pixel by pixel

CCD is mounted on the output phosphor of the __ and coupled with

II

fiberoptics or lens systems

when CCD is directly coupled to II, CCD signal is sampled drives

ABC system

CCD advantages high

spatial resolution

SNR

DQE

CCD advantages no

lag/blooming

spatial distortion

maintenance

__ response on CCD

linear

flat panel image receptor made of

Made of cesium iodide (CsI)/amorphous silicion (a-Si) pixels

advantages of flat panel image receptor

distortion free images

constant image quality

Reads in progressive mode (not interlaced) to proper sharper image with less flicker (sweeps occurs continuously from top to bottom)

video system

Easier to view and manipulate and provide better images

flat panel image display

IR procedures began in

1930s with angiography

opacification of vessels through injection of contrast media

angiography

imaging procedures

angiography

aortography

arteriography

cardiac catherization

myelography

venography

interventional procedures

stent placement

embolization

intravascular stent

thrombolysis

balloon angioplasty

astherectomy

important factors of digital subtraction angiography

image matrix size, system dynamic range, image
acquisition rate

output signal of digital subtraction is transmitted to __ which digitizes it

analog to digital converter

subtraction techniques provide better

contrast resolution

used most frequently, image obtained at one
time is subtracted from an image obtained during the intervening period

temporal subtraction

uses two different beams to correspond to k shell energies

energy subtraction

combine temporal and energy subtraction

hybrid subtraction

initial x-ray pulsed image is made and stored in primary memory, shown on monitor

mask mode

mask is followed by series of images with

contrast (on second monitor)

mask image overlaid to

“erase” parts you don’t want to see

progressive masks and frames that follow each mask

Time-interval difference (TID)

patient moves between the mask and another image, so
the mask doesn’t overlay exactly

registration artifacts

shift the mask to help it overlay when registration artifacts occur

reregistration

roadmapping 1st step

mask is acquired and stored

roadmapping 2nd step

contrast is injected and subtraction images acquired

roadmapping 3rd step

last image inverted and overlaid allow visualization

has inner stylet that is removed once the artery is accessed.

seldinger needle

__ fed into bore of needle then needle is removed

guidewire

__ fed over guide wire

catheter or sheath

most common site for arterial access

femoral artery

allow radiologist to position catheter

guidewire

guidewires made of __ with various types of tips

stainless steel

guide wire may be coated with __ to glide more easily

hydrophilic material

commonly used because it deflects off artherosclerotic plaque
and reduces damage to artery

J-tip

diameter of catheter described in

French (Fr)

examples of catheters

H1 (headhunter)

Fisher

C2 or cobra

Pigtail

After catheter is placed, a __ checks placement before connecting to the power injector

small test injection

__ contrast media to view vessels

radiopaque (nonionic)

Nonionic has low concentration of ions (low osmolality), so

physiologic issues and chance of adverse reaction is reduced

After procedure is done and catheter(sheath) is removed, must

hold pressure on site to stop bleeding

patient must remain immobile for several hours to

prevent bleeding and observe site

most common complication of arteriography

bleeding at puncture site

serious adverse reaction of arteriography

blood clot formation

injury to vessel

IR suite must be big enough to accommodate

equipment and entire team

procedure room should have finishes appropriate for a

sterile environment

control room should have __

and __ with filtered incoming air

viewing area

positive air pressure

personnel in IR procedures

2 or more rad techs

radiology nurse

radiologist

rad techs may take __ registries

cardiovascular (CI) or vascular interventional (VI) ARRT

IR room have a mounted

c-arm

x-ray tube has

small target angle

large anode disc

cathode designed for magnification

small focal spot of no greater than __ is required to see small vessels

0.3 mm

__ images made with DR are lower patient dose per frame than a spot film camera

static