Introduction to Radiology PDF

Dr Joshua Lauder, Consultant Radiologist Learning objectives  What is radiology?  Why do I have to know about it?  Radiology modalities  Xray  CT  Nuclear medicine  Ultrasound  MRI  Post DICOM What is radiology? ‘Using technology to see living anatomy’...

Dr Joshua Lauder, Consultant Radiologist Learning objectives  What is radiology?  Why do I have to know about it?  Radiology modalities  Xray  CT  Nuclear medicine  Ultrasound  MRI  Post DICOM What is radiology? ‘Using technology to see living anatomy’  Diagnostic Interventional Why do I need to know radiology? Why do I need to know radiology? 2021-22 43.3 million imaging tests  21 million Xrays,  10 million Ultrasounds  6.6 million CT Scans  3.7 million MRI Scans  Radiology modalities Xray Ultrasound CT MRI Nuclear medicine Xrays Xray Ionizing radiation?  Xray Advantages Disadvantages Quick Ionizing radiation Available Poor soft tissue detail Good bone detail 2D representation of 3D structures Good lung detail Sir Godfrey Houndsfield 1919 - 2004 CT Concepts 1. Anatomical planes 2. Orientation 3. Density (Hounsfield units) 4. Windowing 5. Contrast 1. Anatomical planes 2. Orientation 2. Orientation 1+2 Anatomical plane orientation 3. Density 3. Density (Hounsfield Units) 3. Density Fat -80 Air -1000 Contrast +300 Bone Muscle +500 +50 4. Windowing 4. Windowing  4. Windowing Soft tissue window Lung window Bone window 5. Contrast 5. Contrast  CT Advantages Disadvantages Still quick 3D view Ionizing radiation +++ Can see vascular Can’t see spinal cord structures (with contrast) Less detail in the brain Poor tendon/ligament detail Nuclear medicine Xray Nuclear medicine Nuclear medicine Nuclear medicine  V/Q  Bone  PET  Nuclear medicine Advantages Disadvantages Provides functional information, depending on pharmacokinetics of the radioactive isotope Ionizing radiation ++ Poor anatomical detail Radiation Dose 2.2 mSv one year background 7 mSv in Cornwall  Radiation Dose (2.2 mSv one year background) Chest X-ray 0.04 mSv (1 week) CT Chest, abdomen and pelvis 8 mSv (4 years) Fatal cancer risk* maybe 1 in 20,000 per mSv Ultrasound Ultrasound 0.001 0.0001 1 000 000 10 000 000 Ultrasound starts at 2MHz How ultrasound works  Piezoelectric effect How ultrasound works How ultrasound works How ultrasound works Echogenicity Reflected Transmitted Inbetween Echogenicity Reflected Transmitted Inbetween Echogenicity Reflected Transmitted Inbetween Echogenicity Reflected Transmitted Inbetween Echogenicity Anechoic Hypoechoic Isoechoic Hyperechoic Echogenicity  Which renal lesion is a tumour? Ultrasound attenuation High frequency Low frequency Ultrasound guided procedures  Ultrasound Advantages Disadvantages Quick Available No radiation Operator dependent Repeatable Excellent soft tissue Can’t see through bone resolution Can see blood flow Can’t see through air MRI  Magnetic resonance imaging  NMR – nuclear magnetic resonance No ionizing radiation Magnets Radiowaves MRI CT Xray CT MRI Neuro imaging Musculoskeletal imaging  MRI Advantages Disadvantages Excellent soft tissue Slow - artefacts detail Contraindications Fluid sensitive (can see oedema) Claustrophobic Bony detail not as good as No ionizing radiation xray or CT  Radiology modalities Xray Ultrasound CT MRI Nuclear medicine  https://www.postdicom.com/en/share?Share=8d2 4db1f-76b0-41fb-994a-08aac59bcac0&Lang=0 Password - anatomy