RadEd

Zachary T Lowery
  • 5.0 (1)
  • EDUCATION

This is a podcast about all things radiology designed for medical students, residents, attending radiologists, and anyone else interested! The goal of this podcast is to educate people on and explore the field of radiology. Topics covered include: diagnostic imaging modalities, important radiology concepts/findings, current research topics in the field, technologies and procedures of the field, social and ethical challenges, radiology as a career, interviews with radiologists, and much more!

Episodes

  1. 08/02/2022

    Deep Dive: Nuclear Medicine

    Basic concept: using radioactive (element that remits radiation as it decays) substances coupled with biologically active chemicals to visualize structures (some organs love certain substances- like thyroid and iodine) Important physics concepts to know:Isotope = element on the periodic table with different # of neutrons but same atomic # Radioisotopes: technetium-99m, iodine-131 How nuclear medicine actually works: patient is made radioactive, they emit gamma rays, a gamma camera has a detector made of crystal that scintillates in response, computer creates an image, multiple types of scans that utilize this principles Types of scans:Positron emission tomography (PET) = uses radioisotope that produces positively charged electrons (positrons) that are attached to pharmaceuticals (glucose analog fluorodeoxyglucose [FDG] for example) to image based on metabolic activity Single photon emission computed tomography (SPECT) = uses gamma camera to take 2D pictures circling around the patient to create a 3D projection Bone scans:Screening for metastatic disease, diagnosing early fractures Tracer = Technetium-99m (Tc99m) methylene diphosphonate (MDP)Deposits best where there is bone turnoverMetastases, superscan, triple-phase Ventilation/perfusion (V/Q) scans:Used to diagnose pulmonary embolism when patients cannot undergo CT angiography Tracer = Tc99m macroaggregated albumin (MAA)Pulmonary embolism = segmental mismatch with normal ventilation but abnormal perfusion scans; probability can be categorized into normal, low, intermediate, high Cardiac scans:Heart cells with decreased perfusion or viability will take up less tracerUsually perform a resting and stress (adenosine, treadmill) scanDecreased uptake on stress that corrects on rest suggests ischemia rather than infarct (reversible vs irreversible) GI bleed scans:Couple Tech-99m to RBCs and scan abdomenBleeds show up as increased uptake of radiotracer in bowel lumen that increases in amount and moves through the bowel over time Thyroid scintigraphy:Used to assess nodules, Grave’s disease, cancerHyperyhyroid patients will show increased uptake if there is truly an increased amount of thyroid hormone being actively produced Performed using radioactive iodine or T99m pertechnetate which both go to the thyroid 95% of hot nodules are benign, cold nodules are more concerning for malignancy Biliary scans:Hepatobiliary iminodiacetic acid (HIDA) scan = couples Tc99m to iminodiacetic acid to assess the hepatobiliary systemOften used to diagnose acute cholecystitis (very sensitive and specific) or biliary leaks after surgery Lack of filling of the gallbladder (photopenic area) suggests obstruction of cystic duct and can diagnose acute cholecystitis Can scan the abdomen to see if tracer is outside of biliary system to suggest leak References: Herring's Learning Radiology, Nuclear Medicine: The Requisites, Radiopaedia, Mandell's CORE Radiology

    22 min

  2. 07/05/2022

    Chest X-Ray: Lung Anatomy

    Understanding normal anatomy is key before being able to understand what is abnormal Anatomy reviewVisceral pleura hugs the lungs (forms fissures), parietal pleura lines chest wallLobes of the lung: right lung has upper, middle, and lower lobes, left lung has upper and lower lobesFissures: right lung has horizontal/minor fissure and oblique major fissure, left lung has one huge oblique major fissure  Invisible or fine white lines, if thickened may represent excess fluid from a process such as congestive heart failureTrachea -> carina -> main bronchus -> lobar (secondary) bronchi -> segmental (tertiary) bronchi -> subsegmental bronchi -> bronchioles -> secondary lobules (centrilobular artery and bronchus) -> respiratory bronchioles -> alveoli Cannot usually see bronchi on chest x-rayConduction zone = trachea, bronchi, bronchioles, terminal bronchiolesRespiratory zone = respiratory bronchioles, alveolar ducts, alveoli Lung parenchyma = alveoli, ducts, and respiratory bronchiolesType 1 pneumocytes do gas exchange, type 2 pneumocytes produce surfactant, alveolar macrophages ingest and process debrisHemidiaphragms: left is obscured by heart, on lateral radiograph can follow the right hemi all the way acrossLeft main pulmonary artery arches over the left main bronchus The right pulmonary artery will be anterior and inferior to the bronchus/left pulmonary artery on lateral radiographEach pulmonary artery may appear as slightly opaque compared to the lumen of the bronchus Pulmonary vessel markings taper peripherally and will show up as white lines thicker at the base of the lung Lungs have supply from pulmonary arteries and bronchial arteries (from aorta)Pulmonary veins drain into left atriumInnervation: parasympathetic from vagus, sympathetic from thoracic ganglia Lymph drainage goes to hilum Physiology: parasympathetic causes vasoconstriction, bronchoconstriction, gland secretion, sympathetic does opposite and opens things up  Lateral radiograph is important to view areas of the lung that may not be obviously abnormal on frontal view Normal features of lateral radiograph:Space behind the sternum (lack of could point to mediastinal masses)Absence of a major shadow from the hila (presence could point to sarcoidosis)Consistent height of vertebraeSharp posterior (requires less fluid to visualize) costophrenic angles (blunted/opacity filled could point to pleural effusion)Continuous right hemidiaphragm (and slightly higher) As with all studies/indications, when looking at an image, do not forget to look at all of the structures in field of view; even if you are reading a chest x-ray to rule out pneumonia/pneumothorax, remember to view all of the other structures, such as the thoracic vertebrae! References: Herring's Learning Radiology, Radiopaedia, Mandell's CORE Radiology

    8 min

  3. 06/28/2022

    Chest X-Ray: Basics

    Indications: broad (respiratory or cardiac disease, tube positioning, trauma)  Characteristics of a good chest x-ray (PIER): Projection (AP, PA, lateral, lateral decubitus): heart will appear bigger on AP,  but not by much, AP is better for intubated/sick patients, two views is KEYInspiration and ribs: do you see at least 8-9 posterior ribs (if too little inspiration, things can crowd and mimic abnormalities)Exposure: can you see the spine through the heart (too much penetration makes things dark, too little makes things bright and fuzzy)Rotation and clavicles: what is the relationship between the clavicles and thoracic spinous processes (patient rotated to their right will have their left clavicle appear closer to the spinous process)Angle of patient: should be perpendicular, but x-ray beams may be angled upward (apical lordotic), which can make anterior structures look more superior (clavicles above first rib) ApproachStart every time with verifying patient information and imaging quality (PIER)/information Then execute your systematic approach for consistency Common approach is the tubes + ABCDEFGHI approachFirst looks at tubes, lines, drainsA = airway, B= bones, C = cardiac, D = diaphragm, E = effusions/extra-thoracic tissues, F = fields, fissures, foreign bodies, G = great vessels, gastric bubble, H = hilum and mediastinum, I = impressionA/airway = follow the trachea down, is it midlineB/bones = follow outline of bones to look for fracturesC/cardiac = heart should be around or less than 50% diameter of chestD/diaphragm = right hemi is slightly higher due to liver, are they flattenedE/effusions and extra-thoracic tissues = check costophrenic angles, lateral films, look for swelling, subcutaneous airF/fields, fissures, and foreign bodies = check lung fields for opacities, masses, pneumothorax, vessel markings, look at major and minor fissures, assess any foreign bodies (wires)G/great vessels and gastric bubble = follow path of aorta, pulmonary arteries and veins, gastric bubble under left hemidiaphragmH/hilum and mediastinum = look for prominence (sarcoid), lymphadenopathy, masses, check for mediastinal widening (thymus can be normal in kids)I/impression = overall conclusion or what is going on considering your findings  References: Herring's Learning Radiology, Radiopaedia, Mandell's CORE Radiology

    11 min

  4. 06/25/2022

    Imaging Modalities

    If this episode doesn't fascinate you, I don't know what will!! RadiographsIonizing radiation hits a photosensitive film to produce an imageDigital radiography: photosensitive plate processed by electronic reader to be stored digitallyPACS system: picture archiving, communications, and storage systemPlain films = X-ray = radiograph = without contrast materialAdvantages: availability, less expensiveDisadvantages: limited detail, uses radiation (caution in pregnancy)Uses: chest x-ray, abdomen x-ray, bone visualization DensitiesAir is black (absorbs the least), bone is white (calcium), metal appears whitest, fat and soft tissues appear in between as gray  CT scannersUses x-ray machine that rotates around patient to create different planes and produce a large series of 2D images slicesImportant to understand positioning of patient from image (you're look up from the bottom of their feet, with patient's right on the left of the screen)Hounsfield units: -1000 to +1000, water is zero, air is -1000, bone is +400-600, fat is -40 to -100, soft tissues is 20-100Windowing: range of densities to most optimally view certain structuresAdvantages: greater detailDisadvantages: more radiation, more expensive Uses: non-contrast head CT for stroke, traumas, 3D reformats  UltrasoundUses high frequency sound waves emitted from a probeAdvantages: less expensive, availability, no ionizing radiationDisadvantages: operator dependent, low resolution Uses: great for pregnancy, gallstones, breast masses, thyroid nodulesDoppler flow: red towards probe, blue away from probe MRIUses magnetic fields and radio waves to affect hydrogen items Advantages: great resolution, no radiationDisadvantages: expensive, time-consuming, special precautions (pacemakers)Uses: brain imaging (MS), soft tissues like muscles, tendons, ligaments, herniated discs, spinal cord pathologies  FluoroscopyUses ionizing radiation in real-time Can give barium to a patient which will show up blackUses: esophagrams, voiding cystourethrograms, interventional radiology (angiography)Advantages: mobile, procedure guidance, dynamicDisadvantages: higher dose of radiation Nuclear medicineUses radioactive substances (elements that emit radiation as they decay) and couples them with drugs that will accumulate in certain tissuesDifferent types of scans: positron emission tomography (PET) scans use radioactive glucose (fluorodeoxyglucose, FDG), single photon emission computed tomography (SPECT) uses a gamma camera to acquire images from many angles to create a 3D mapDifferent organs use different substances; the brain loves glucose and the thyroid loves iodine Uses: cancer imaging, assessing for metastasesLess radiation than CT scans, but must use caution with radiation exposure via shielding and appropriate timing  References: Herring's Learning Radiology, Radiopaedia, Mandell's CORE Radiology

    14 min

  5. 06/15/2022

    Introduction

    Welcome to the RadEd podcast! In this episode: purpose, vision, goals for the podcast Disclaimer

    2 min
  • 5 Episodes

About

This is a podcast about all things radiology designed for medical students, residents, attending radiologists, and anyone else interested! The goal of this podcast is to educate people on and explore the field of radiology. Topics covered include: diagnostic imaging modalities, important radiology concepts/findings, current research topics in the field, technologies and procedures of the field, social and ethical challenges, radiology as a career, interviews with radiologists, and much more!

Information

  • Creator
    Zachary T Lowery
  • Years Active
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  • Episodes
    5
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    © 2022 RadEd
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