Sonographic guided procedures and treatment

Liver Bx, Renal Bx, Thyroid Bx, Thora, Para, FNA requires …

A skin puncture

PT and international normalized ratio (INR) should be assessed prior to________ and assess clotting ability

Any invasive procedure

Normal INR

0.8-1.1

Normal INR for pt on blood thinners

2-3

Hypertension and insulin should ______ be taken before a procedure

Not

Informed consent

Lists procedure and potential associated risks and complications

Must be signed prior to the procedure and after physician answers questions

Role of sonographer during procedures

Describe procedure to pt and warm them of noise of Bx device

Instruct pt on different positions and breathing

Confirm the pt can cooperate

Obtain signed consent

Time out

Pull up priors

Select proper transducer

Perform preliminary scan and locate path

Optimize image and take images during procedure

#1 advantage of sonography guided Bx

Real time vis or needle passing through area of interest

Disadvantages of US guided Bx

Isoechoic lesions

Sound attenuation

Unable to eval GI or bones

Contraindications of sonographic guided procedures

Known allergy to injectate

Lack of equipment or skills

Unsafe Bx route

Uncooperative pt

Unmanageable coagulopathy

Complications of US guided procedures

Hemorrhage, pain, vasovagal response, hematoma, swelling, peritonitis, biloma, urinoma, pneumothorax, infection, death, needle track seeding

Most common major complication of Bx of a solid abdominal organ

Hemorrhage

FNA

Small needle used with a syringe to draw out cells or fluid from a superficial mass

Much less risk than core Bx, samples evaluated by cytology

Fine needle capillary technique

Needle is moves in and out of tissue to obtain cells

Aspirates a smaller, but more concentrated sample of cells than FNA

Core Bx

Uses automated device with hollow core needle

Removes a core sample of tissue within the hollow needle

Evaluated by histology

Needle guide helps maintain a constant path for needle but limits choice of Bx path/needle angle

Requires assessment of PT and INR levels prior to procedure

Percutaneous aspiration/Drainage

Uses a fine needle for serous fluid

Renal, liver and ovarian cyst drainage usually performed for symptom relief due to side

Catheter can be left in for many weeks to drain abscess but requires saline irrigation 3-4 xday

Artifacts seen posterior to a Bx needle

Reverberation or posterior shadowing

Paracentesis

Aspiration of fluid from the peritoneal cavity

Performed for diagnostic and therapeutic reasons

Eval abdomen for largest pocket

US guidance to indert needle

Pt in semi erect position

Liters for therapeutic Paracentesis

6L

Thoracentesis

Removal of fluid from the pleural space in the thoracic cavity

Performed for diagnostic or therapeutic reasons

Chest X-ray done before and after

Keep pt in same position in pre-procedure images and during procedure

Semi-erect leaning over a table

No absolute contraindications

Hypotension and pulmonary edema can occur if _____ liters of fluid are removed in one day in a thoracentesis

1.5

Liver Bx

Performed due to abnormal labs, staging of parenchymal diseases and/or mass evaluation

Done with FNA or core needle Bx

Pt should be NPO

Right lobe Bx’s use an intercostal approach with the pt in the left oblique position

Liver Bx is most commonly performed to evaluate

Liver disease/damage

Percutaneous Ethanol Injection (liver)

US guidance is used for the injection

Absolute ethanol commonly used to treat hepatocellular carcinoma or liver mets from colon cancer in pts where liver resection is not an option

Can be helpful in controlling the tumors until the pt can have liver transplant

Ethanol is injected into tumor(s) to cause necrosis and fibrosis of the tumors

Acetic acid is another type of injectable used for liver tumor treatment

Radiofrequency ablation of liver tumors

Performed percutaneously or intraoperatively

Induces thermal injury tissue using electromagnetic energy with a frequency <900kHz

An electrode is placed into the lesion and a high-frequency alternating current is delivered

The current causes ionic agitation and frictional hear, leading to protein denaturation and necrosis of tumor cells

Works well for hepatocellular carcinoma and mets

Renal Bx indications

Hematuria, proteinuria, nephritic syndrome, acute renal failure, renal allograft

rejection

Renal Bx is most commonly performed to

Eval parenchymal disease; less commonly for mass characterization

Most common site for renal Bx

Lower pole

Renal Bx

Pt placed in prone position with pillow under abdomen for great vessel puncture

Transplant kidneys are Bx in supine position

Gross hematuria is abnormal finding after renal Bx but microscopic hematuria is seen in nearly all pts after renal Bx

Any cystic structure should be evaluated with color to r/o pseudoaneurysm

Most common reason for adrenal Bx

Confirm metastatic disease in a pt with known primary and an adrenal mass

Adrenal Bx

Right adrenal is easier to vis and Bx b/c liver acts as window

If pheochromocytoma is being Biopsied, the pt may need to take alpha-adrenergic blockers to prevent hypertensive crisis

Prostate Bx

Performed to confirm malignancy

Indications include elevated PSA levels and abnormal digital or manual rectal exam

Most commonly performed with pt in LLD position

Left side of the gland poses an increased risk for puncture of urethra

Thyroid Bx

Uses FNA or FNC

Not recommended for nodules less than 10mm

Recommended for nodules with microcalcs >10mm; >15mm and solid; >20mm cystic or complex

Color Doppler used to eval gland for vessels

Pt is supine with neck extended

Percutaneous Ethanol Injection (thyroid)

Injection of ethanol into thyroid cysts, benign thyroid nodules, enlarged parathyroid glands, cervical nodoal mets

Causes tissue necrosis/fibrosis, vessel thrombosis and infection

4-8 sessions for thyroid nodules/cysts

More effective for smaller nodules

Parathyroid adenomas, also require multiple injections that are repeated daily or every other day

Pseudoaneurysm treatment

Pocket of blood contained in tissues outside an artery that has been puncutred

Commonly associated with interventional cardiology procedures

Sonography guided compression

Least invasive treatment for pseudoaneurysm but not effective if larger than 3-4cm

Also may cause intolerable discomfort for pt due to continuous compression

Compression is performed in 10 intervals of one minute each

Color Doppler eval of flow within the pseudo is performed after each compression interval

Percutaneous thrombin injection

Success rate 97%

Low-dose thrombin injection into body of the pseudoaneurysm to cause clotting to occur and occlude the stalk/neck

Migration of the thrombin downstream is a potential complication

Not recommended in patients with larger diameter pseudoaneurysms >5cm and wide necks >1cm

Central venous catheter placement

Used when peripheral IV access is not an option, or when large volumes of fluid or medications are required

Commonly referred to as peripherally inserted central catheters or PICC lines

3 primary sites for catheter insertion: IJV, subclavian, femoral veins

Preprocedural scan is performed to assess vascular anatomy for variants and r/o abnormalities

Needle is placed at 45 degree angle

US is used to monitor insertion to confirm the insertion into correct vessel

Parallel linear echogenicity

Interoperative ultrasound

Surgical procedures that require a sterile field

Transducers should be soaked with alcohol 30min prior

Ethylene oxide gas can also be used to sterilize probe

Acoustic gel inside sheath but not outside

What should be stopped 7 days prior to an invasive procedure

Blood thinners, Ibuprofen, NSAIDs

The national patient safety standards recommend a time out period prior to the start of an invasive procedure. How will you comply with this recommendation during a renal Bx

Record a blank image that says time out after consent form is signed and then another image at the start of the procedure

What will help the radiologist select the correct biopsy needle size/length for the Bx of a mass in the posterior right liver?

Measuring the depth of the mass within the liver

What is an absolute contraindication

A condition that makes a procedure absolutely inadvisable

______________ refers to when a tissue sample is removed, tumoral cells can be released into the blood or lymphatic system causing the formation satellite tumors and/or mets

Needle track seeding

What described an ultrasound guided invasive procedure

Sterile gloves must be used to put the sterile sheath on the probe

If the sonographer is scanning during the procedure, they must be wearing sterile gloves and gown

A sonographer who is not sterile must be making machine adjustments

Preferred location for catheter insertion for a para

Left paracolic gutter

Where is the preferred location for catheter insertion for a thora

Lower than ninth rib

Percutaneous ethanol injection and radiofrequency ablation are commonly used to treat tumors formed by:

HCC

Why is the lower pole of the left kidney the most common site of parenchymal biopsy

Because there is the least risk of great vessel puncture

Guidelines for compression therapy for pseudoaneurysm

Compress the pseudo with a 10 one-minute intervals and apply color Doppler after each interval

Normal USA of a longitudinal view of an IV catheter is:

Parallel linear echogenicities