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INTERVENTIONAL RADIOLOGY & ANGIOGRAPHY. DR. Walid Asaad , MBBS, MD, DABR,CAQ Diagnostic &Interventional Radiology King Abdulaziz University Hospital. INTERVENTIONAL RADIOLOGY
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INTERVENTIONAL RADIOLOGY & ANGIOGRAPHY DR. WalidAsaad, MBBS, MD, DABR,CAQ Diagnostic &Interventional Radiology King Abdulaziz University Hospital
INTERVENTIONAL RADIOLOGY • A subspecialty which provides minimally invasive techniques with the help of imaging modalities to diagnose or treat a condition. • Minimally invasive • Local anesthesia • Early recovery
8 out of 10 procedures use skin incisions smaller than 5 mm. • 9 out of 10 procedures use only local anaesthetic, sometimes with sedation. • Up to 8 out of 10 patients go home the same day
INTERVENTIONAL RADIOLOGY • Stent placement • Embolization • Thrombolysis • Balloon angioplasty • Atherectomy • Electrophysiology
Percutaneous biopsy • Abscess drainage • Percutaneous nephrostomy • Percutaneous Biliary drainage • Radiofrequency ablation
ANGIOGRAPHY • The radiologic examination of vessels after the introduction of a contrast medium.
HISTORY • The first angiogram was performed only months after Roentgen's discovery of X rays. • Which was when? • Two physicians injected mercury salts into an amputated hand and created an image of the arteries
Interventional radiologic procedures began in 1930s with angiography. • In early 1960s Mason Jones pioneered transbrachial selective coronary angiography. • Later in 1960s transfemoral angiography was developed.
BASIC PRINCIPLES • Arterial access • In 1953 Seldinger described a method for catheterization of vessels. • A percutaneous technique for arterial and venous access. • Femoral artery is most commonly used.
SELDINGER TECHNIQUE • Seldinger needle. • 18gauge single use,sterile needle. • 2 parts-- a solid inner needle(stylet) & an outer thin wall needle for smooth passage. • a hub---good instrument balance • winged handle---good control.
Site cleaned, area draped, local anesthetic given. • The seldinger needle is introduced into the artery. • When pulsating blood returns, the stylet is removed.
A guide wire is inserted through the needle. • With guide wire in vessel, needle is removed. • Catheter is threaded onto the guide wire. • Under fluoro, the catheter is then advanced and the guide wire is removed.
GUIDEWIRES • Guide the catheter. • Allow safe introduction of catheter into the vessel. • Made of stainless steel. • Usually about 145cm long • An inner core wire that is tapered at the end to a soft flexible tip.
Covered by a coating—teflon, heparin and recently hydrophilic polymers(glide wires) are used. • Coating reduces friction, gives strength to GW. • Tips at the end of GW • Straight • J- tipped—prevents subintimal dissection of artery.
CATHETERS • Many shapes and sizes. • diameter is given in French(Fr)—3Fr=1mm. • Straight- end hole only—smaller vessels/minimal contrast. • Pigtail- circular tip with multiple side holes —larger vessels/ more contrast.
H1 or Head hunter tip– used for femoral approach to brachiocephalic vessels. • Simmons catheter is highly curved --- for sharply angled vessels--cerebral and visceral angiography. • C2 or Cobra catheter has angled tip joined to a gentle curve—celiac, renal & mesenteric arteries.
Judkins catheters Right(lesser curve) & left(greater curve) for right & left coronary arteries. • Amplatz catheters Right & left coronary arteries
Contrast Media • Initially ionic iodine compounds were used. • Now non ionic contrast media in practice—low adverse reactions and low physiologic problems.
INDICATIONS • Diagnosis & presence of ischemic heart disease. • After revascularization procedures • Congenital heart lesions & anomalies of great vessels. • Valve disease, myocardial disease & ventricular function.
Atheroma • Aneurysms • Arteriovenous malformations • Arterial ischemia • Trauma
Patient preparation • Explain procedure & risk to the patient. • History & physical examination. • Lab tests. • Consent • Pre procedure I/V fluids. • Medication to relieve anxiety.
Monitoring during and after procedure • ECG, Automatic BP measurement & pulse oximetry. • Life saving drugs and equipments. • Immobile for minimum 4hrs after. • Vital signs monitored. • Puncture site inspected.
Contra-indications • Contrast allergy • Impaired renal function • Blood- clotting disorders • Anti coagulant medication • Unstable cardio pulmonary/ neurological status
Risks • Bleeding at puncture site • Thrombus formation • Embolus formation –plaque dislodged from vessel wall by catheter • Dissection of vessel • Puncture site infection ( contaminated sterile field) • Contrast reaction
INTERVENTIONAL RADIOLOGY SUITE • Specifically designed to accommodate the quantity of equipment needed & the large number of people involved in the procedure.
Interventional radiology suite • Procedure Room • Room size- 400-600 square feet • Easily cleaned (floors, wall, etc.) • Outlets needed for O2, suction. • At least three means of access. • Control Room • 100-150 square feet • Easy access and communication to procedure room • Operating console with Computers, monitors .
EQUIPMENTS • The X-ray apparatus for interventional radiology is more massive,flexible,expensive & advanced. • More heat load and serial images.
X RAY TUBE • Two ceiling track-mounted X-ray tubes alongwith an image intensified fluoroscope mounted on C or an L arm. • A large diameter massive anode disc(15cm diameter, 5cm thick) to accommodate heat load. • Cathodes designed for magnification & serial radiography.
A large focal spot of 1mm for heat load. • A small focal spot( no more than 0.3mm) is necessary for spatial resolution of small vessel magnification.
Power rating of 80kW—for rapid sequence serial radiography. • Anode heat capacity of 1 MHU—to accommodate heat load.
Generators • High frequency and high voltage generators • Three phase,12 pulse power.
Patient couch • Stationary couch with a floating,tilting or rotating table top. • Controls for couch positioning are located on side of table and also on a floor switch. • May also have a computer controlled stepping capability.
Image receptor • 2 different types. • Cinefluorographic camera—now obsolete. • Nowadays Digital image receptors are used with a television camera pickup tube or a charge-coupled device(CCD).