Special Procedures Assignment P2

What is a guidewire?

• tool used to safely introduce and accurately position catheters in vessels

• stainless steel wire with winner core tapering into soft, flexible tip

• hydrophilic coating to reduce friction

What is an introducer sheath?

short catheter used when multiple catheter exchanges are anticipated during a procedure

What are (automatic) injectors and what components does a typical device consist of?

devices used to safely deliver a preset amount of contrast, and large bolus injections, safely into a vessel

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consists of:

• control panel

• syringe

• warming device

• pressure mechanism

Describe high level control fluoroscopy (HLCF)

• operating mode on special fluoro equipment

• substantially higher entrance rad’n levels than in routine practices

• used where visualization of fine catheters, or structures not easily seen, is crucial

What are ways to limit dose to PTs?

• max distance between PT and tube, min distance between PT and IR

• limit use of mag mode

• use last image hold

• collimate

• use pulsed fluoro and low frame rate

What are ways to limit dose to operators and staff?

• keep hands out of primary beam

• wear proper protective equipment (aprons, gloves, goggles)

• follow best practices with tube/IR placement

  • horizontal = stand on IR side

  • vertical = tube under table

What is digital subtraction?

software used to remove overlying structures (bone, tissues) so displayed image only shows vessels of interest that contain contrast media

• image taken without contrast

• contrast is injected

• algorithm removes structures from original image

• only contrast filled structures remain in displayed image

What is misregistration?

artifact that occurs when a PT moves during serial image acquisition

What is re-registration / pixel shifting?

post-processing technique used to realign current image(s) with original mask image

• used to correct slight movement

What is remasking?

post-processing technique where a new mask image is taken to be used for digital subtraction

• used to correct significant movement/misalignment from original mask

What is road mapping?

special application of DSA; uses DSA image as a mask to better navigate guidewire/catheter placement

• mask image taken and stored

• contrast injected

• first set of subtraction images acquired

• subsequent images are then taken using the subtracted images as the new mask, resulting in highlighted vessels and visualization of a guidewire/catheter

What is the Seldinger technique? (in general, not the steps)

widely used percutaneous (through the skin) vascular access technique

• minimizes bleeding

• removes surgical risk associated with previous methods

What are the 4 most common puncture sites?

• femoral

• axillary

• brachial

• radial

What are the steps of the Seldinger technique?

1. Artery punctured with a needle

2. Beveled compound needle with an inner cannula pierces the artery

3. Needle withdrawn slowly until there is blood flow

4. Inner cannula is removed and flexible guidewire is inserted

5. Needle is removed over the wire, and pressure is used to fix the wire and reduce hemorrhage

6. Catheter slipped over the guidewire into the artery

7. Guidewire is removed leaving only the catheter in the artery

What is a PTA?

percutaneous transluminal angioplasty

• angiographic procedure used to dilate stenosed vessels

What are the diagnostic uses for a nephrostomy tube?

• Assess renal function

• urine culture

• brush biopsy

• determine cause of urinary tract dilation

• nephroscopy

• failed attempts at retrograde pyelography

What are the therapeutic uses for a nephrostomy tube?

• Ureteral obstruction secondary to stones or other obstructive pathologies

• chemolysis

• abscess drainage

What level is an IVC placed?

Below renal arteries around L1-L2

What are some purposes of transcatheter embolization?

• stop blood flow to site of pathology

• reduce blood flow to highly vascular tumor before surgery

• stop active bleeding

• deliver chemotherapeutic agents

What is thrombolysis?

procedure used to dissolve clot/thrombus

• catheter inserted into vessel

• thrombolytic agents injected through catheter

What is radiofrequency ablation?

• minimally invasive procedure to destroy tumor

• needle electrode skewers tumor

• radiofrequency is passed through electrode multiple times

• friction > heat > destruction of tissues

• dead tumor gradually replaced by scar tissue

What is a vertebroplasty?

• percutaneous fluoro guided procedure

• acrylic cement inserted into vertebral body

• used to reduce pain from compression fractures

What is a kyphoplasty?

similar to vertebroplasty

• first balloon is inserted into vertebral body and inflated to reduce compression

• acrylic cement is then injected to stabilize vertebra

During aspiration, what action is taken if aspirated fluid is purulent?

drainage continues

During aspiration, what action is taken if aspirated fluid is sterile?

fluid is withdrawn and needle is removed, procedure is finished

What is administered before a drainage procedure (PBD), and when is this administered?

antibiotics should be administered 1 hour prior to a drainage procedure

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PTs may have infected bile/fluid; antibiotics are given to prevent possible spread of infection

How many samples are taken during a biopsy?

At least 4 to include center and peripheral areas