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Interventional Radiology
Interventional Radiology - โ ANS *Diagnose disease (while providing diagnostic information through angiographic procedures *Intervene in or interfere with, the course of a disease process or other medical condition, providing a therapeutic outcome through interventional radiologic procedures Angiography - โ ANS Radiologic examination of vascular structures within the body after introduction of iodinated contrast medium or gas Angiographic procedures are categorized as either visceral or peripheral and can be further classified into the following major procedures - โ ANS Arteriography Venography Angiocardiography Lymphography Arteriography - โ ANS imaging of the arteries Venography - โ ANS imaging of the veins Angiocardiography - โ ANS imaging of the heart and associated structures Indications of Angiography - โ ANS *Primarily used to identify the anatomy or pathologic process of blood vessels.
*Most angiographic exams are performed to investigate anatomic variances but others are used to evaluate the motion of the part Arteriograms - โ ANS Performed to assess the severity of a stenosis or occlusion in a vessel caused by atherosclerosis Cerebral angiography - โ ANS Performed to detect and verify the existence and exact position of an intracranial vascular lesion such as an aneurysm Vascular exams - โ ANS Evaluate the suspected tumors by opacifying the organ of concern The interventional component of radiologic procedures - โ ANS A specialized radiologist uses needles, catheters, and special medical devices to produce an improvement in the patient's status or condition Provide therapeutic treatment for a disease process by: - โ ANS *Treating vascular disease (Stroke, intracranial hemorrhage) *Reducing blood flow to a highly vascular structure and tumor before surgery *Stop active bleeding at a specific site *Delivering a chemotherapeutic agent *Providing alternatives for patients who are not candidates for surgery *Providing shorter recover times because of safer, less invasive procedures *Providing shorter hospital stays *Utilizing techniques that are minimally invasive and lower-risk compared with traditional surgical procedures *Providing a less expensive alternative than traditional medical and surgical procedures Basic Principles of Interventional Radiology -
โ ANS *Usually a water-soluble, nonionic iodinated, and radiopaque compound that is injected through the catheter for visualization of vessels *Nonionic contrast media have replaced ionic compounds because of their low osmolality and reduced risk of allergic reactions and physiologic problems Patient Preparation and Monitoring - โ ANS *Patient is examined and a history is obtained *Assess for allergies and other conditions *Proper procedure and access route determined *Once the patient is considered a good candidate for the angiographic procedure, orders are written for intravenous hydration and a diet of clear liquids *Access site is prepped for needle, wire, and catheter insertion During the angiographic procedure, the patient is monitored - โ ANS Electrocardiography Blood pressure measurements are taken Pulse oximetry- oxygen saturation Contraindications of Angiography - โ ANS Contrast media allergy Impaired renal function Blood-clotting disorders or taking anticoagulant medication Unstable cardiopulmonary / neurologic status Risks of Angiography include: - โ ANS Bleeding at the puncture site (Most common risk) Thrombus formation Embolus formation Dissection of a vessel
Infection of a puncture site Contrast reaction Catheter or guidewire Thrombus formation - โ ANS A blood clot may form in a vessel and disrupt the flow to distal parts Embolus formation - โ ANS A piece of plaque may be dislodged from a vessel wall by the catheter which results in a stroke Dissection of a vessel - โ ANS Catheter may tear the intima of a vessel Infection of a puncture site - โ ANS Caused by contamination of the sterile field Contrast reaction - โ ANS May be mild, moderate, or severe Catheter or guidewire - โ ANS Penetrating injury may occur Common Angiographic Procedures - โ ANS Cerebral angiography Thoracic Angiography Angiocardiography Abdominal Angiography Peripheral Angiography Lymphography Cerebral angiography -
โ ANS *Performed to identify the anatomic and physiologic condition of the heart *Involves the introduction of specialized catheters into the heart and surrounding vasculature for the purpose of diagnostic evaluation and therapy intervention Abdominal Angiography - โ ANS *Demonstrates the contour and integrity of abdominal vasculature *Allows the visualization of abdominal vessels and possible obstructions or vessel tears Peripheral Angiography - โ ANS Radiologic examination of the peripheral vasculature after the injection of contrast media Arteriograms - โ ANS Injection by a catheter into an artery of an extremity Vascular Interventional Procedures: - โ ANS Embolizations Percutaneous Transluminal Angioplasty and Stent Placement Stent-Graft Placement Inferior Vena Cava Filter Insertion of Venous Access Devices Transjugular Intrahepatic Portosystemic Shunt Thrombolysis Infusion Therapy Extraction of Vascular Foreign Bodies Embolizations - โ ANS Uses an angiographic approach to create an embolus in a vessel, thus restricting blood flow
Percutaneous Transluminal Angioplasty and Stent Placement - โ ANS Uses an angiographic approach and specialized catheters to dilate a stenosed vessel Stent-Graft Placement - โ ANS Uses a combination of interventional stents and surgical grafts to treat aortic aneurysms and traumatic vascular injuries Inferior Vena Cava Filter - โ ANS Uses an angiographic technique to place a filter in the inferior vena cava to treat pulmonary emboli Insertion of Venous Access Devices - โ ANS Placement of venous access catheters to administer chemotherapy or large amounts of antibiotics for frequent blood tests and parenteral nutrition Thrombolysis - โ ANS Procedure that uses a dissolving agent injected through catheter into the region of the thrombus or clot, whereby the clot is lysed (disintegrated) Infusion Therapy - โ ANS Uses a range of agents such as vasoconstrictors, vasodilators, chemotherapeutic drugs, and radioactive materials to treat disease Extraction of Vascular Foreign Bodies - โ ANS Procedure that removes foreign bodies such as (calculi, fragments of vascular catheters or guide wires, pacemaker electrodes, and shunts) through the use of loop snares, basket catheters, or endoscopic grasping forceps. Nonvascular Interventional Procedures: - โ ANS Percutaneous Vertebroplasty and Kyphoplasty Enteric Stenting Nephrostomy Percutaneous Biliary Drainage (PBD)
*The biopsy is useful in providing information about the stage and extent of the disease, diagnosing infection, and confirming whether a tumor recurrence occurred Percutaneous Gastrostomy - โ ANS Performed for: Extended feeding (greater than 4 weeks) of patients unable to eat Gastric decompression Dilation of upper GI tract when the oral approach fails Interventional Radiology Equipment - โ ANS Digital Image Acquisition Generator X-ray Tube Image Intensifier (analog or digital) Image processor Contrast medium injection devices Angiographic tables Physiologic monitoring equipment Digital Image Acquisition - โ ANS Involves using computers in conjunction with specialized imaging equipment to produce quality diagnostic digital images. Generator - โ ANS *Typically a multiphase format offering 12 pulses per second that offers high performance capabilities *Allows for high mA stations and low kVp settings that improve the visibility of contrast medium against surrounding soft tissue structures
*Allows for shorter exposure times, which reduce radiation exposure to the patient X-ray Tube - โ ANS *Differ slightly from traditional imaging x-ray tubes because their ability to withstand high amounts of heat due to the extended periods of fluoroscopy and rapid sequences of exposures made over a short period of time. *Constructed with larger diameter anode disks combined with a larger target angle or focal spot size to accommodate for the increased heat production Analog image intensifiers - โ ANS *Require the use of charge-coupled devices (CCD) and an analog-to- digital converter to produce a digital image *CCD replaces the television camera in the vascular imaging system Digital image intensifiers - โ ANS *Acquire images digitally so no special conversion equipment is required *Composed of silicon pixel detectors that are known as flat panels or digital detectors Image processor - โ ANS *Image-processing hardware and a computer --The hardware controls the speed of the imaging equipment and allows the images to be viewed in real-time. --Computer controls various components of the imaging system including the generator, x-ray tube, image-processing hardware, and archiving storage device Contrast medium injection devices - โ ANS Allows for the safe delivery bolus injections of preset amounts of contrast, necessary for angiography Contrast medium injection devices
Digital Angiography - โ ANS *"Spot filming" replaced traditional spot-film devices *Involves the production of one image and is generally used when only a few images are needed for a procedure Digital Subtraction Angiography (DSA) - โ ANS *A highly sophisticated computer "subtracts" or removes bone and soft tissue structures so that the resultant image demonstrates only the vessels of interest containing contrast media *Subtracted image appears as a reversed image and may demonstrate diagnostic information not apparent on a conventional non-subtracted image *Normally used when imaging vessels in the head, chest, and extremities Digital Cineradiography - โ ANS *Involves taking numerous exposures (frames) in a second of time *Used primarily for cardiac catheterization which requires exposure rates of 15, 30, or 60 frames per second *Able to demonstrate events that are normally too fast or cannot be seen by general fluoroscopy
