Diagnostic Radiology The basics : Diagnostic Radiology The basics Dr Muhammad Ishfaq
Dr Tamar Saeed
surgical C, Khyber teaching
hospital, Peshawar. Pakistan
2009 Radiological Modalities : Radiological Modalities X-Ray Projection (plain Radiography)
Nuclear medicine X-Rays/Plain Radiography : X-Rays/Plain Radiography Wilhelm Conrad Röntgen
(27 March 1845 – 10 February 1923)
German physicist, who, on 8 November 1895, produced and detected electromagnetic radiation in a wavelength range today known as x-rays or Röntgen rays, an achievement that earned him the first Nobel Prize in Physics in 1901. Types of Plain Radiography : Types of Plain Radiography A .Film-Screen Radiography
X-Rays passes through body and strikes a cassette containing fluorescent phosphorus.
The area with high radiation will appear
The area with less radiation will appear
B .Computed Radiography (CR)
The x-rays passing through the patient strike a sensitized plate which is then read and digitized into a computer image by a separate machine
C. Digital radiography
The x-rays strike a plate of x-ray sensors producing a digital computer image directly Fluoroscopy : Fluoroscopy Special applications of X-ray imaging, in which a fluorescent screen or image intensifier tube is connected to a closed-circuit television system.
This allows real-time imaging of structures in motion or augmented with a radio contrast agent.
Radio contrast agents ,To delineate anatomy and functioning of the blood vessels, the genitourinary system or the gastrointestinal tract.
Barium (as BaSO4) for evaluation of the GI tract.
Air, can be used as a contrast agent for the gastrointestinal system
Carbon dioxide, can be used as a contrast agent in the venous system; CT scan : CT scan These are x rays
Greek ‘tomos’ means slice & ‘graphein’ writing
n 1900 an Italian
gives the idea
First commercially available in 1972 in UK CT SCAN : CT SCAN .CT imaging uses X-rays in conjunction with computing algorithms to image the body. In CT, an X-ray generating tube opposite an X-ray detector (or detectors) in a ring shaped apparatus rotate around a patient producing a computer generated cross-sectional image (tomogram).
Acquired in the axial plane, while coronal and sagittal images can be rendered by computer reconstruction.
Radio contrast agent
Intravenous contrast can allow 3D reconstructions of arteries and veins Ultrasound : Ultrasound In physics the term "ultrasound" applies to all acoustic energy with a frequency above human hearing (20,000 hertz or 20 kilohertz).
Typical diagnostic sonographic scanners operate in the frequency range of 2 to 18 megahertz, hundreds of times greater than the limit of human hearing ULTRASOUND : ULTRASOUND Uses ultrasound (high-frequency sound waves) to visualize soft tissue structures in the body in real time
Highly dependent on the skill of the person (ultrasonographer)
THERAPEUTIC USE Modes of sonography : Modes of sonography A-mode:
A single transducer scans a line through the body with the echoes plotted on screen as a function of depth. Therapeutic ultrasound aimed at a specific tumor or calculus is also A-mode, to allow for pinpoint accurate focus of the destructive wave energy.
In B-mode ultrasound, a linear array of transducers simultaneously scans a plane through the body that can be viewed as a two-dimensional image on screen.
M stands for motion. In m-mode a rapid sequence of B-mode scans whose images follow each other in sequence on screen enables doctors to see and measure range of motion, as the organ boundaries that produce reflections move relative to the probe.
This mode makes use of the Doppler effect in measuring and visualizing blood flo MRI : MRI Magnetic resonance imaging (MRI), or nuclear magnetic resonance imaging (NMRI), is primarily a medical imaging technique most commonly used in radiology to visualize the structure and function of the body.
It provides detailed images of the body in any plane.
MRI provides much greater contrast between the different soft tissues of the body than computed tomography (CT) does, making it especially useful in neurological (brain), musculoskeletal, cardiovascular, and oncological (cancer) imaging. Unlike CT,
It uses no ionizing radiation, but uses a powerful magnetic field to align the nuclear magnetization of (usually) hydrogen atoms in water in the body MRI : MRI MRI scans give the best soft tissue contrast of all the imaging modalities
MRI has become an essential tool in musculoskeletal radiology and neuropathology NUCLEAR MEDICINE : NUCLEAR MEDICINE Nuclear medicine
imaging involves the administration into the patient of radio pharmaceuticals consisting of substances with affinity for certain body tissues labeled with radioactive trace.
The most commonly used tracers are Technetium-99m, Iodine-123, Iodine-131, Gallium-67 and Thallium-201.
The heart, lungs, thyroid, liver, gallbladder, and bones are commonly evaluated for particular conditions using these techniques.
Anatomical detail is limited in these studies, nuclear medicine is useful in displaying physiological function.
With computer processing, the information can be displayed as axial, coronal and sagittal images (SPECT images)
In PET scanning, a radioactive biologically-active substance, most often Fluorine-18 Fluorodeoxyglucose, is injected into a patient and the radiation emitted by the patient is detected to produce multi-planar images of the body. Pre investigation preparations : Pre investigation preparations Contraindications : Contraindications Radiological hazards : Radiological hazards Radiological hazards : Radiological hazards : Extravasations
(1)Dehydration (& cell death)of surrounding tissues and (2)Compartment syndrome- Treatment:
i. RICE (Rest, Ice-pack, Compress, Elevate extremety
ii. Watch for compartment syndrome, especially if large volum Contrast induced nephrotoxicity
Defined as a 25% increase in serum creatinine - Prevention: - i. Any high risk factors: Pre-hydrate patient
- iii. Space out contrast studies 72h apart, if possible (e.g. cancer staging) - iv. Consider non-contrast CT or alternate studies (e.g. US, MRI) - Paradoxically,
patients whose kidneys have already failed and are on dialysis can ignore all the above. Acute Hazards and management Acute hazards and management : Acute hazards and management (4) Metformin-induced lactic acidosis - Metformin: Stop on the day, and 2 days after the scan. - Once again, do this proactively, if you think patient might be going for a contrast-CT soon! (Just don’t forget to convert to insulin/another OHGA, and to re-start it later!) (5) Breast feeding - Can scan as per normal, but no breast feeding x 24h after the scan
Management as for other drugs.
prednisolone Thank you : Thank you