Medical Fundamentals of Angiography

This e.learning will provide information so that the technologist will have a better understanding of the anatomy and physiology of the circulatory system. The material will also review the different types of angiography, the workflow and acquisition types for each.<

By the end of this course, you will be able to: Understand the definition and indications for angiography Identify disorders of vascular structures Describe the circulatory system and major blood vessels Explain contrast media, digital subtraction and angiography workflow Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer bibendum sem in est interdum consectetur. Morbi sodales congue neque, quis consequat eros iaculis sed. Nunc luctus volutpat eros, ullamcorper commodo magna suscipit ac. Vestibulum vel arcu metus, nec egestas elit. Pellentesque commodo tellus arcu. Vivamus adipiscing consequat dignissim. Nam placerat tortor eget sem mattis rhoncus. Nulla pellentesque lectus eget lorem commodo interdum. Phasellus in ligula id eros aliquet vehicula. Duis auctor sollicitudin lectus id dignissim. Morbi ac tempor arcu. Vivamus placerat neque eu ipsum fermentum sollicitudin. Etiam in consequat ligula. Cras eu nisl ligula, vel tristique magna. Nulla facilisi. Morbi vel pellentesque mauris. Nam non dolor ipsum, ac gravida justo. Donec mi urna, ultrices et auctor nec, varius a nunc. Display of blood vessels Arteries Veins  Performed with digital radiography techniques Contrast agent is infused into the blood vessels so that they become visible To display: Vascular changes Constructions (stenoses) Blockages (occlusions) Disorders of the vascular wall Arteriosclerosis The course of vessels Anomalies (congenital, acquired) Congenital malformation of the superior vena cava and other veins Compression of the superior vena cava caused by a tumor Vascular supply of expanding processes (tumors) Vascular anomalies / vascular neoplasms Aneurysms AV shunts (AV malformations) Angiomas Traumatic lesions Ruptures Sources of hemorrhaging General Angiography Cardiac Angiography Neuro Angiography The study of: Head and neck regions (cerebral, cervical) Torso (abdominal region) Arms and legs (peripheral region) Pulmonary arteries The study of: Heart Coronary vessels Pulmonary arteries The study of: All cerebral vessels The basics of anatomy and physiology will now be discussed. Universal transport system of the human body Transports the following substances in a "system of tubes" Respiratory gases Nutrient media and catabolic products Hormones Protective cells and antitoxins Fluids Heat     Heart The pump or motor Arteries Vessels which carry blood away from the heart Veins Vessels which carry blood back to the heart Capillaries Hairline vessels interconnecting the veins and arteries Muscular sack not subject to voluntary control Pumps blood into the blood vessels Transports blood into the: Lungs (pulmonary circulation) Body (systemic circuation) Comprised of four chambers Left and right atria Left and right ventricles Performs approximately 65-75 contractions per minute in its normal resting state     Blood is transported via the upper and lower vena cava to the right atrium of the heart To the right ventricle of the heart via the tricuspid valve Through the pulmonary arteries into the pulmonary capillaries to exchange carbon dioxide (CO2) and oxygen (O2) To the left atrium via the pulmonary veins To the left ventricle via the mitral valve Throught the aortic valve into the aortic arch and on to the aorta Blood is distributed in the cirulatory system as follows: Approximately 12% in pulmonary circulation Approximately 15% in the arteries Approximately 59% in the veins Approximately 5% in the capillaries Approximately 9% in the heart Blood flows at a speed of: Up to 50 cm/s in the arteries Approximately 0.3 cm/s in the capillaries Up to 20 cm/s in the veins Characterized by strong vascular walls Must withstand high pressures Have a thick, elastic muscular layer Substantially thinner vascular walls Weaker muscular layer Larger inner diameter Withstand lower pressures Larger veins have valves to prevent reverse blood flow Consist of a thin membrane which enables metabolic exchange with tissues and organs of the body Average diameter of only 8 thousandths of a millimeter (0.008 mm) Play a decisive role in regulating the temperature of the body If body temperature rises, skin's blood supply increases to "cool off" the blood at the surface of the body. (e.g., response to inflammation)     Main artery of the body which branches off into the following arteries Coronary vessels - supplying the heart Supraaortal vessels - supplying the cervical and cranial regions of the arms Thoracic vessels - supplying the chest cavity Abdominal vessels - supplying the abdominal cavity Distal peripheral vessels - supplying the pelvis and the legs A substance which attenuates x-rays either more or less than normal tissue does Normal contrast media (positive contrast) containing iodine Gaseous contrast media (negative contrast) carbon dioxide can be used under certain conditions   Blood is not visible in an x-ray image Dynamic blood flow processes can be displayed without injecting contrast medium (CM) only in magnetic resonance imaging (MRI) scans. Recent bleeding, (e.g. cerebral hemorrhaging), is readily detectible in computed tomography (CT) scans, however normal blood flow is not visible Iodine Has a high atomic number and high density Causes a stronger attenuation (absorption) of x-rays than blood Discharged through the kidneys Carbon Dioxide Has very low density Attenuates the x-rays only slightly Is a "natural" substance for the body Ionic Contrast Media Dissociates into charged particles in blood Non-ionic Contrast media Dissociates into neutral particles in blood Fewer allergic reactions More expensive Cannot be administered with standard injectors Subjects the patient to pain (bed of nails) Yields poor image contrast Can be used only in the lower region of the body (abdomen, pelvis, legs) where risk of embolism is lower Discharged (exhaled) via the lungs Fluoro images Iodine contrast is displayed in black Regular x-ray films Iodine contrast is displayed in white DSA and DA images Iodine contrast is normally displayed in black Usually selectable at the modality Carbon Dioxide contrast, because it is a negative contrast Displayed in white in Fluoro, DSA and DA images Displayed in black in regular x-ray films Local anesthesia Small skin incision via scalpel Puncture Insertion of guide wire Insertion of a catheter Injection of contrast media x-ray exposure series Skin puncture until blood flow is obtained through needle Threading of a guide-wire into the vessel Removal of needle Tracking of arterial sheath and its internal dilator Removal of guide-wire and dilator Groin - transfemoral (femoral artery or femoral vein) Elbow - transbrachial (brachial artery or brachial vein) Armpit - transaxillary (axillary artery) Direct punctures Abdominal aorta - translumbar Carotid artery  Overview Catheters - several sideholes (e.g., 6) and an endhole Selective Catheters - usually only one or two sideholes Digital acquisition (DR)Native Series Single Digital Cine Acquisition Digital Cine Mode (DCM) Digital Subtraction Acquisition Digital Subtraction Angiography (DSA) Native imaging Displays not only the desired vascular structures, but also the bones, ribs, and organs to the extent that they attenuate x-rays Subtraction images Only the vessels are displayed The procedure is based on photographic subtraction, first described in 1934 by the Dutch radiologist Dr. Ziedses des Plantes X-ray film exposure without contrast media Inverse copy of exposure without contrast media - mask (precontrast) image X-ray film exposure with contrast media - filled (CM-filled) image The mask and filled images are exactly superimposed A copy of the two superimposed films is then prepared - subtraction image Digital exposures are taken Contrast media is injected with a time delay so that at least one of the exposures contains no contrast media The images are immediately subtracted by the processor The subtraction scene is displayed on a TV monitor (on-line) in real time     Mask Image minus Fill Image equals Subtracted Image     Survey radiography Injection through a main artery, (e.g. the aorta or vena cava) All vessels branching off from this vessel are displayed; vessel overlapping is possible Selective display Direct injection through the vessel of interest Only the branches which come off of this vessel are displayed; vessel overlapping is thus largely prevented Advantages Lower amount of contrast media required Minimal overlapping of vessels Display of even the finest vascular structures High detail recognition Disadvantages Increased preparation necessary Immobilization of patient Immobilization of part   1-2 days prior to examination Take a sample of the patient's blood to determine the coagulation factors and kidney function Ask the patient if he/she has any allergies Instruct the patient and explain reactions ot contrast media Obtain the patient's consent At the day of examination Warm up the contrast media to body temperature   Instruct the patient not to move and position the patient comfortably Make sure no anatomical movements occur, i.e.: no respiratory movements no swallowing movements medicinal reduction of intestinal movements in the abdominal region during DSA Check the correct adjustments: patient-to-I.I. distance exposure format collimation and absorption correction   To ensure the best image quality: Administer injection at the correct time (depending on type and location of injection) Use a sufficient concentration and amount of contrast media (depending on type and location of injection) Use optimized exposure programs Guide the patient with breathing and swallowing commands   Designation and Labeling You should now be able to: Understand the definition and indications for angiography Identify disorders of vascular structures Describe the circulatory system and major blood vessels Explain contrast media, digital subtraction and angiography workflow

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