Ultrasound-Guided Interventional Techniques Flashcards
What locations of organs and masses are ultrasound being used to perform a variety of invasive procedures?
-neck, chest, abdomen, retroperitoneum, musculoskeletal, pelvis, and to drain various fluid and abscess collections
What procedures can ultrasound be used to do?
- biopsy malignant or benign masses
- biopsy organs for parenchymal disease or transplant rejection
- drain fluid collections
- drain or obtain samples of abscesses
- assist in placement of drainage tubes or catheters
- assist in placement of catheters in vessels
- mark spots for fluid taps to be performed w/o direct sonographic guidance
What are the advantages of ultrasound guidance?
- continuous real-time visualization of biopsy needle
- allows adjustment of needle as needed during procedure
- allows different patient positions and approaches
- patient may be turned into decubitus or oblique position to allow safe access to mass
- subcostal approaches allow use of steep angles
What are the disadvantages of ultrasound guidance?
- not all masses can be visualized
- mass may be isoechoic to normal tissue
- look for indirect signs of the presence of a mass (displaced vessels, capsule bulges, tumor vessels)
- other limitations may include sonographer inexperience
What are indications of biopsy?
- to confirm malignancy in mass and determine whether mass is primary tumor or metastatic
- to differentiate a malignancy from inflammatory or infectious disease
- to differentiate recurrent tumor from scarring
- to characterize a benign mass
What are contraindications of ultrasound guidance?
- only a few since it’s minimally invasive
- uncorrectable bleeding disorder, lack of safe needle path, or uncooperative patient
What lab tests are needed for ultrasound guidance?
-bleeding times but blood or urine tests are typically not requested before US guided procedure
What are the types of US guided procedures?
- FNA: Fine Needle Aspiration
- Core Biopsy
What is a FNA?
-FNA, or cytologic aspiration, uses thin-gauge needles to obtain cells from within mass
What type of needles are used for FNA?
-performed using 20- to 25- gauge needle with cutting tip (Franseen, Chiba, Spinal needle)
What is a core biopsy?
-uses an automated, spring-loaded device called a biopsy gun to obtain core of tissue for histologic analysis
What are the two methods for performing US-guided procedures?
- Free hand technique
- Use of needle guides
What is the free hand technique?
- performed w/o use of needle guide
- transducer placed in sterile cover
- radiologist will hold transducer in one hand and the needle in other hand
- care taken to align needle w/ transducer and sound beam
- technique allows more flexibility in choosing needle path
- more technically challenging, especially on deep lesions
*What is the free hand technique typically used for?
-*to drain ascites, pleural fluid, and superficial lesions
What do some physicians prefer using free hand technique for?
-thyroid biopsies, native renal biopsies, and renal transplant biopsies
What is the needle guide technique?
- involves using needle guide
- attached to transducer
- predicted needle path displayed on screen as single line or as two parallel lines
- mass lined up along path
- some transducers offer choice of angles
- this gives some flexibility around vessels or other structures
What are the benefits of using needle guide?
- faster placement of needle
- ability to keep needle going through anesthetized area when multiple passes required
What are biopsy complications?
- usually minor and include post-procedural pain or discomfort, vasovagal reactions, and hematomas
- serious complications are rare
What are rare serious complications from biopsy?
-bleeding, hemorrhage, pneumothorax, pancreatitis, biliary leakage, peritonitis, infection, possibly death
What is the sonographer’s role in interventional procedures?
- locate pathology
- determine various approaches
- offer recommendation for best and safest needle path
- use scanning skills to optimize image
- use doppler to ensure no vessels in needle path
- place patient in variety of positions
- may need to discuss and determine solutions to problems like needle deviation
- can also gently remind physician that patient is holding his or her breath
- can be second set of hand as needed to adjust imaging controls
How to find tip of the needle?
-should appear as echogenic dot on image
What factors does visualizing the needle tip depend on?
- type of needle
- gauge of needle
- transducer frequency
- focal zone
- echogenicity of mass
What can be done to help see the needle?
- move needle up and down or jiggle stylet
- scan and angle transducer in superior and inferior motion
- use harmonics or compound imaging
- remove needle and start again
