interventional radiology Flashcards
- vascular recanalization techniques
used to restore blood flow
vascular recanalization :
- restore bf because of ats, thrombosis, embolus
- embolize vessel: in treatment of AVM, aneurysms, fistulas.
indications:
- limb ischemia, subclavian steal syndrome, renal artery stenosis, DVT, May turner syndrome.
o Introduction:
- Interventional radiology is a subspecialty of radiology in which minimally invasive procedure are performed using image guidance
- Common imaging modalities include fluoroscopy, CT, US, MRI
o Angiography:
- Is a medical imaging technique used to visualize the inside or lumen of blood vessels - Interest in arteries, veins and the heart chambers
- Done by injecting a radio-opaque contrast agent into the blood vessels and imaging using X ray based techniques such as fluoroscopy
- The film or image of the blood vessel is called angiograph/angiogram
- uses iodinated contrast, gadolinium, CO2 gas
- used with CTA and MRA (diagnostic purposes)
o Angioplasty or PTA:
- Technique of mechanically widening a narrowed or obstructed blood vessel - Balloon catheter on a guide wire is passed into vessels and inflated to a fixed size using pressure (6-20 atmospheres)
- the balloon crushes the fatty deposits, so opening up the blood vessel to improve flow - The balloon is then collapsed and withdrawn
- May include placement of stents (balloon expandable or self-expandable)
- Done by seldinger technique (puncture with a sharp, hollow needle 🡪 guidewire through the lumen of needle 🡪 needle withdrawn 🡪 sheath passed over the guidewire into cavity 🡪 withdrawn of guidewire
o Thrombolysis:
- Treatment aimed at dissolving blood clots with pharmaceuptical (TPA) or mechanical means - E.g pulmonary emboli, DVT, thrombosed hemodialysis accesses
o Thrombectomy:
- Either balloon ebolectomy as previously described
- Aspiration thrombectomy (removal of thrombus by suction)
- Surgical thrombectomy (incision into a vessel)
- endovascular treatment of arterial aneurysms - pseudo-aneurysms - AV fistulas
Aortic aneurism:
- Cause: arteriosclerotic 85% (thoracic), diccecting 15% (thoracic), inflammatory 1% (thoracic) - Info: arteriosclerotic usually distally to the aortic arch, fusiform or saccular, calcified often, older, hypertension
- Info: Post-traumatic aneurysms: typically occur in the aortic arch on the side of the lesser curvature and are caused by an abrupt shearing effect (whiplash injury)
- Indication: requires treatment when it exceeds a diameter of 5 cm
- Treatment is performed with stent grafts (EVAR – endovascular aneurysmal repair) - Stent grafts are metal grid meshes coated with a solid material, used to neutralize aneurysms (aortoiliac), hemorrhage, or AV fistulas!
- To use it, it is important to visualize and measure the aneurysm as well as the diamters of the aorta and the pelvis
- Stent grafts must have the exact required dimensions in order to be properly fixed and manipulated
- Stent grafts have a continuous coat and cannot be inserted through renal arteries because this would lead to obstruction
- 🡪 thus, proximal landing zone is a crucial factor
- Criteria: diameter of the aorta at level of the renal arteries, length of the proximal landing zone, diameter and course of vessel in the pelvis
o Pseudoaneurysm:
- Caused by traumatic arterial bleeding
- Etiology: needle puncture, biopsy, knife stab
- Blood that flows out is covered and compressed by parts of the adventitia and surrounding body tissue
o Stent assisted coiling:
- For wide necked aneurysms stent can be placed to hold coil mass inside the aneurysm o AV fistula:
- abnormal connection between artery and vein (directly)
- Diminished blood supply to tissue because of capillary bypass
- Usually occur in legs, but can appear everywhere
- Often surgically created in people with severe kidney disease
- treatment: ultrasound-guided compression (ultrasound probe is used to compress fistula and block blood flow to the damaged blood vessel), this is for leg fistula
- treatment: catheter embolization: x-ray imaging to guide catheter and a small coil or stent Is placed at site of fistula
- treatment: surgery
- Endovascular embolization techniques
The goal: occlude hypervascular tumor/ fistulas
o Non-surgical, minimally-invasive procedure perfomed by an interventional radiologist and interventional neuroradiologist
- Usually fluoro guidance
- Permanent or temporary agents
- Examples: bronchial, splenic, pelvic, post trauma
- Need to spare as much normal parenchyma as possible
- It involved the selective occlusion of blood vessels by purposely introducing emboli
- Indication: wide variety of condition affecting different organs:
1. Cerebral aneurysm
2. AVMs (arterial, venous, lymphatic)
3. Gastrointestinal bleeding (also renal, hepatic, pulm, pelvic)
4. Epistaxis
5. Primary post-partum hemorrhage
o Procedure in growths:
- Used to slow or stop blood supply, thus reducing size of the tumor
- Liver lesions (HCC) by partial infarction or transcatheter arterial chemoembolization - Kidney lesions
- Uterine fibroids
o Other:
- Portal vein
o Embolic agents
- Alcohol (sclerosing agent)
- Glue (injectable fluid agent)
- Metallic coils (especially for brain aneurysms)
- Embospheres
- Gelfoam (absorbable agent) - sometimes used in acute stage in trauma
- embozene: precisely calibrated microscpheres made for greater embolization control
- Vena cava filters
o Introduction:
- Is an endovascular device which is typically placed in the infrarenal inferior vena cava (IVC) - To prevent pulmonary embolism in selected patients
- Performed under fluoroscopic guidance
o Procedure:
- puncture of internal jugular / femoral vein (US guided)
- guidewire placed in IVC
- obtain venogram : admn contrast through catheter in lower IVC / distal common iIiac v
- dilate venous assess
- vena cava filter is deployed in (typically infrarenal IVC )
- get another venogram to make sure placement of filter is correct
- remove delivery system and secure hemostasis (by manual compression)
o Indication:
- Contraindication to anticoagulation, e.g active GI bleed or recent neurosurgery
- PE despite anticoagulation
- Poor patient compliance with anticoagulation treatment
- Large iliocaval or floating IVC thrombus
- Temporary vena cava filter is typically placed for a short duration (weeks to months) - In certain patients they are left in situ indefinitely, these devices may be called permanent filters
o Contraindications
- Circumstances when a vena cava filter cannot be placed are rare
- Complete vena cava thrombosis
- Vena cava is too small or too large to safely admit a filter
- Septic thromboembolism
- IVC filters are indicated in only a small proportion of patients who have venous thromboembolism
- In these situations, retrievable filters are recommended
- Anticoagulation should be initiated after filter placement as soon as it is safe to do so and the filter should be removed shortly thereafter
- TIPS (transjugular intrahepatic portosystemic shunt )
watch a youtube video of the procedure , i cant picture it
Introduction:
- Transjugular intrahepatic portosystemic shunt (TIPS)
- Direct communication is formed between hepatic vein and a branch of portal vein - This allows some proportion of portal flow to bypass the liver
- Ultrasound-guided vascular access gained via right internal jugular vein
- 🡪 with a vascular sheath inserted into the right atrium for initial pressure measurement - 🡪 angiographic catheter advanced into a hepatic vein, and hepatic venography is performed
- 🡪 Curved TIPS puncture needle advanced into hepatic vein
- 🡪 Portal venogram is performed with contrast injected through the TIPS puncture needle
to confirm portal vein cannulation
- 🡪 Balloon catheter used to dilate liver parenchyma 🡪 stent deployed over vascular sheath
o Indication:
- Treatment for complications of portal hypertension
- Typically in patients with decompensated liver cirrhosis
- Accepted indications for TIPS include the following:
1. Uncontrolled variceal hemorrhage from esophageal, gastric and intestinal varices
2. Refractory acites
3. Hepatic pleural effusion
4. Bridge to transplantation and retransplatation (controversial)
5. Budd-chiari syndrome (controversial)
6. Hepatorenal syndrome (controversial)
7. Veno-occlusive disease (controversial)
o Contraindications:
- Severe and progressive liver failure
- Severe encephalopathy
- Polycystic liver disease
- Severe right-heart failure
- Portal and hepatic vein thrombosis (relative)
- Pulmonary hypertension (relative)
- Hepatopulmonary syndrome (relative)
- Active infection (relative)
- Tumor within the expected path of the shunt
o Complications:
- Hemorrhage in peritoneum
- Hepatic infaction
- Gallbladder puncture
- Sepsis secondary to infection
- Percutaneous biopsy
o Introduction:
- Definition: Taking a tissue sample from area of interest for pathological examination from a percutaneous approach
- US, CT or Fluoroscopy
- Random sampling or sampling of a mass
- Lung, mediastinum, pleura, chest wall, nodes
- Liver adrenal gland, pancreas, kidneys, lymph nodes
o CT guided thoracic biopsy (radiopedia): - Usually performed for the diagnosis of suspicious lung, pleura or mediastinal lesions - Indications: Pulmonary lesion inaccessible to bronchoscopy, mediastinal mass, pleura mass Contraindications: - Poor respiratory function or reserve - Uncooperative patient - Lack of safe access - Uncorrectable bleeding diathesis Complication - Pneumothorax (most common) - Hemoptysis - Parenchymal hemorrhage - Air embolism
o Ultrasound guided breast biopsy (radiopedia)
- Widely used technique for an accurate histopathological assessment of suspected breast pathology
- Fast, safe and economical procedure
Indication:
- Suspicious abnormality
- An abnormality highly suggestive of malignancy
Contraindications:
- Aspirin or anticoagulant use are not ABSOLUTE contraindication
Complications:
- Bleeding
- Local haematoma
- Non diagnostic sample
- percutaneous aspiration and drainage
o Introduction abscess:
- US, CT or fluoroscopy guided
- Aspiration or drainage tube placement
- Usually for infection
- Pleura, lung
- Hepatic (intra/sub), pericolic gutters, perisplenic, peri/intrapancreatic, pouch of douglas, psoas, abdominal wall
- Abscesses amenable to intervention are drained with special drainage sets under US or CT guidance
- Care of the drain and regular controls are important to ensure constant flow - Type of abscesses includes: intraperitoneal, retroperitoneal, thoracic, soft tissue o Introduction PTCD (percutaneous transhepatic cholangiodrainage):
- The indications include benign stenosis, malignant stenosing tumors with secondary cholestasis
- A congested bile duct is separated by means of percutaneous puncture, and a guidewire is introduced into the duodenum/jejunum through the stenosis
- The stenosis is then dilated and a stent inserted
o CT guided percutaneous drainage: (radiopedia)
- Minimally invasive treatment of collections, potentially anywhere
- Less commonly used than US
- Gains access to deeper or more posterior parts of the body
- Better visualized as certain areas than US
o Ultrasound guided percutaneous drainage: (radiopedia)
- Minimally invasive treatment of collections
- No radiation and does not require as wide a range of staff as with CT
- Deeper targets may not be well-visualized
- Indication:
1. Complicated diverticular abscess
2. Crohns disease related abscess
3. Abscess from appendicitis
4. Renal, splenic, hepatic abscess
5. Post-surgical fluid collection
- Contraindications: bleeding diathesis
- Radiofrequency ablation
o Introduction:
- Is a medical procedure in which tumor or other dysfunctional tissue is ablated using heat generated from medium frequency alternating current
- RFA procedures are performed under image guidance (x-ray screening, CT, ultrasound) o Indications:
- Tumors in lung, liver, kidney and bone
- Tumors in other areas also, but less commonly
- Once diagnosis of tumor is confirmed 🡪 RFA needle probe placed inside tumor - Radiofrequency waves passing through the probe increase temperature within tumor tissue and results in destruction of the tumor
- RFA can be used with small tumors
- RFA can be used for primary or MTS tumors
- Treatment of HCC, pancreatic cancer and bile duct cancer, colorectal cancer - Important in care of benign bone tumors, most notably osteoid osteoma
- RFA is also increasingly used in the palliative treatment of painful metastatic bone disease - Varicose veins
- Alternative to the traditional stripping operation
- Radiofrequency catheter inserted into abnormal vein and the vessel treated with radio energy 🡪 closure of the involved vein
- Used to treat great saphenous vein, the small saphenous vein and the perforator veins
- Bile duct interventions
o Introduction of cholangiography and biliary drainage:
- Fluoro, US
- Cholangiogram – inject transhepatically into biliary tree and intervene with plastic or metal stents, stone removal, plasty, etc.
- Drains/stents can be internal, internal-external or external
- Interventions tend to be painful so need good anesthesia
- Often useful when GI cannot delineate lesion retrograde
o Introduction PTCD (percutaneous transhepatic cholangiodrainage):
- The indications include benign stenosis, malignant stenosing tumors with secondary cholestasis
- A congested bile duct is separated by means of percutaneous puncture, and a guidewire is introduced into the duodenum/jejunum through the stenosis
o PTBD (percutaneous transhepatic biliary drainage):
- Indications are benign stenosis, but usually malignant stenosing tumors with sec. cholestasis
- A congested bile duct is probed by percutaneous puncture, and a guidewire is introduced into the duodenum/jejunum through the stenosis
- The stenosis is then dilated and a stent Is inserted
o Percutaneous cholecystostomy:
- Image-guided placement of drainage catheter into gallbladder lumen
- Minimally invasive procedure
Indications:
1. Risk of acute calculous or cholecystitis
2. Unexplained sepsis in critically ill patients
3. Access to or drain of biliary tree following failed ERCP and PTC
o ERCP (endoscopic retrograde cholangiopancreatography):
- Using both endoscopy and fluoroscopy for examine and intervention of biliary tree and pancreatic ducts
- Passing endoscope to the descending duodenum and cannulating the ampulla of Vater - Inject contrast to biliary tree
- Requires MRCP or CT intravenous cholangiogram
- Pneumobilia is common post-ERCP
- Used for biopsy, and visualization of bile ducts, removal of stones
- GIT interventions
o Esophageal stent:
- Treatment option in patients with esophageal strictures
- Placed using the guidance of fluoroscopy (x-ray) and endoscopy
- Most commonly used for symptomatic relief in those with dysphagia secondary to malignancy
- The stent is typically covered in nature and inserted endoscopically or fluoroscopically - The distal esophagus is the most common site
- Most stents inserted are self-expandable
Procedure:
- Ultraflex stent, wall stent, Z stent
Complication:
- Pain, bleeding, stent slippage/migration, Tumor overgrowth, esophageal perforation (rare) o Intussusception reduction:
- Procedure performed in pediatric patients who have an ileocolic intussusception - Assessment with ultrasound prior to the reduction allows risk assessment Several ways that reduction can be achieved radiologically:
1. Air-reduction:
- Catheter inserted into the rectum of child under fluoroscopic guidance 🡪 air instilled into large bowel
- Pressures in the region of 60-100 mmHg 🡪 reduce the intussusception back to ileocolic valve
2. Water-reduction:
- Catheter inserted into the rectum of child under fluoroscopic guidance 🡪 Water instilled into the large bowel
3. Physical reduction under US guidance
Risk:
- Perforation, but without reduction an operation is required, so risk worth taking - Rectum most likely to perforate (important to monitor diameter of rectum during procedure)
o Gastrostomy tubes: (practical interventional radio)
- Fluoro guidance facilitating direct percutaneous placement of G tube into the stomach - Indicated for pts with difficulty swallowing often due to neurological or ENT causes - G tubes can also be placed by surgery but IR is less invasive
- Gi can also place G tubes except when the esophagus is blocked by a mass
- Interventional radiology in gynaecology
o Uterine artery embolization:
- Interventional technique to occlude the arterial supply to uterus
- Been practiced for more than 20 years
Indication:
- For controlling hemorrhage (PPH) following delivery/abortion
- Persistant puerperal hemorrhage (PPH) secondary to atonic uterus, uterine tear at time of c-section, bleeding post hysterectomy, placenta accreta
- Ectopic or cervical pregnancy, gestational trophoblastic disease or carcinoma cervix - Intramural fibroids (menorrhagia, bladder outlet obstruction and hydronephrosis) - Adenomyosis
Contraindications:
- Severe anaphylactic reaction to contrast media
- Uncorrectable coagulopathy
- Severe renal insufficiency
- Pregnancy
- Active pelvis infection
- Connective tissue disease
o Procedure:
- With x-ray fluoroscopy guidance
- Pelvic ultrasound and MRI pre-procedural
- Use of catheter inserted to uterine artery
- If not available, can puncture common femoral artery for contralateral access to uterine arteries
o Embolic agents:
- PVA, embospheres, gel foam, cois, glue
Complications:
- Uterine artery rupture
- Post-embolisation syndrome
o Pelvic congestion syndrome:
- Condition resulting from retrograde flow through incompetent valves in ovarian veins - It is one of commonly missed and potentially treatable cause of chronic abdominal or pelvic pain
- Considered female equivalent to a testicular varicocele
Epidemiology:
- More common in multiparous, premenopaused women
- Women with chronic pelvic pain over 6 months
Symptoms:
- Pelvic pain (dull and aching)
- Tight or vulvar varices
Etiology:
- Venous obstruction: retroaortic left renal vein
- Compression of left renal vein by superior meseteric artery (nutcracker phenomenon lol), or right iliac vein compression
- Incompetent valves in ovarian vein
Diagnosis:
- Multiple dilated, parauterine veins with a width > 4mm or an ovarian vein diameter greater than 5-6 mm
- Ultrasound
- CT (contrast CT shows dilated pelvis and ovarian veins)
- MR venography (may show dilated veins)
Treatment: (ovarian vein embolization):
- Interventional technique
- contraindicated in allergic reactions to contrast media, coagulopathy, renal insufficiency - Venous access through internal jugular route or femoral venous route
- 🡪 Vascular sheath in selected vein
- breast and chest diseases - interventional techniques
o Breast:
Fine needle aspiration biopsy: (FNAC)
- Safe, fast and easy approach (inexpensive)
- Thin hollow needle + negative pressure made by syringe attached to the needle - USG guidance
- Aspirated cells are placed on a glass cover slip and immersed in
- High rate of insufficient samples (disadvantage)
- Inability to differentiate between invasive and non-invasive cancers (disadvangage) - minimal-invasive tissue sampling for pathologist
- ultrasound as a targeting instrument (also CT, MRI or fluoroscopy)
Core-cut biopsy:
- Currently the most commonly used technique (most accurate diagnosis)
- Targeted sampling of tissue for histo exam
- USG/stereotactic (x-ray) guidance
- Standard is to obtain 6 samples (needle inserted 6 times)
- Larger thick needle with hollow middle, small cut is made
- Comlications: bleeding, infection, PNO in deeply-located lesions
- Type of ultrasound guided percutaneous breast biopsy
- Wide used for accurate histopathological assessment of suspected breast pathology - Fast, safe and economical procedure
Vacum mamotomy:
- Stereotactic breast biopsy performed as diagnostic procedure when mammography shows irregularities with micro calcification, parenchymal distortions
- Under MR guidance, eventually USG
- Through small cut in the skin a special biopsy needle is inserted into breast using vacuum powered instrument, several tissue samples taken!
- The vacuum draws tissue into the centre of the needle and a rotating cutting device takes the samples
- Series of x-rays taken from 2 different angles to locate area of abnormality o Chest:
- Aspiration, drainage, biopsy (pleura, lungs)
- Lungs – embolization, RFA
