Ultrasound-Guided Interventional Techniques

Question 1

What locations of organs and masses are ultrasound being used to perform a variety of invasive procedures?

Answer 1

-neck, chest, abdomen, retroperitoneum, musculoskeletal, pelvis, and to drain various fluid and abscess collections

Question 2

What procedures can ultrasound be used to do?

Answer 2

• 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

Question 3

What are the advantages of ultrasound guidance?

Answer 3

• 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

Question 4

What are the disadvantages of ultrasound guidance?

Answer 4

• 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

Question 5

What are indications of biopsy?

Answer 5

• 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

Question 6

What are contraindications of ultrasound guidance?

Answer 6

• only a few since it’s minimally invasive

- uncorrectable bleeding disorder, lack of safe needle path, or uncooperative patient

Question 7

What lab tests are needed for ultrasound guidance?

Answer 7

-bleeding times but blood or urine tests are typically not requested before US guided procedure

Question 8

What are the types of US guided procedures?

Answer 8

• FNA: Fine Needle Aspiration

- Core Biopsy

Question 9

What is a FNA?

Answer 9

-FNA, or cytologic aspiration, uses thin-gauge needles to obtain cells from within mass

Question 10

What type of needles are used for FNA?

Answer 10

-performed using 20- to 25- gauge needle with cutting tip (Franseen, Chiba, Spinal needle)

Question 11

What is a core biopsy?

Answer 11

-uses an automated, spring-loaded device called a biopsy gun to obtain core of tissue for histologic analysis

Question 12

What are the two methods for performing US-guided procedures?

Answer 12

• Free hand technique

- Use of needle guides

Question 13

What is the free hand technique?

Answer 13

• 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

Question 14

*What is the free hand technique typically used for?

Answer 14

-*to drain ascites, pleural fluid, and superficial lesions

Question 15

What do some physicians prefer using free hand technique for?

Answer 15

-thyroid biopsies, native renal biopsies, and renal transplant biopsies

Question 16

What is the needle guide technique?

Answer 16

• 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

Question 17

What are the benefits of using needle guide?

Answer 17

• faster placement of needle

- ability to keep needle going through anesthetized area when multiple passes required

Question 18

What are biopsy complications?

Answer 18

• usually minor and include post-procedural pain or discomfort, vasovagal reactions, and hematomas
• serious complications are rare

Question 19

What are rare serious complications from biopsy?

Answer 19

-bleeding, hemorrhage, pneumothorax, pancreatitis, biliary leakage, peritonitis, infection, possibly death

Question 20

What is the sonographer’s role in interventional procedures?

Answer 20

• 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

Question 21

How to find tip of the needle?

Answer 21

-should appear as echogenic dot on image

Question 22

What factors does visualizing the needle tip depend on?

Answer 22

• type of needle
• gauge of needle
• transducer frequency
• focal zone
• echogenicity of mass

Question 23

What can be done to help see the needle?

Answer 23

• 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