L2 - A -1.pdf

Course Instructor Dr.Ali Hayder ALI IMAGING MODALITIES AND MEDICAL APPLICATIONS  Lecture 2 Topics:  Medical applications.  Imaging modalities.  Imaging Modalities OF Diagnostic Radiology  Imaging Modalities used in d...

Course Instructor Dr.Ali Hayder ALI IMAGING MODALITIES AND MEDICAL APPLICATIONS  Lecture 2 Topics:  Medical applications.  Imaging modalities.  Imaging Modalities OF Diagnostic Radiology  Imaging Modalities used in diagnostic radiology  Plain x-rays  CT scan  MRI Which of  Nuclear imaging/PET these  Ultrasound modalities  Mammography use ionizing  Angiography radiation?  Fluoroscopy  A/Plain films or Conventional Radiography  Also called “plain films” or “standard films”  Image formed using broad beam ionizing radiation  The image formed is related to the subjects density  May involve the use of contrast agents  Iodinated  Barium  Air Plain abdomen x.ray Diagram of image formation by x.ray Indications for requesting x.ray  CHEST X.RAY: Radiographic examination of the lungs is performed for a wide variety of medical conditions, including primary lung disease and pulmonary effects of diseases in other organ systems. Such effects produce significant changes in the appearance of the lung parenchyma and may vary over time depending on the nature and extent of the disease. ABDOMEN AND PELVIS CAVITY  Obstruction of the bowel;  Perforation;  Renal pathology;  Acute abdomen (with no clear clinical diagnosis);  Foreign body localization);  Toxic megacolon;  Aortic aneurysm;  Prior to the introduction of a contrast medium, e.g. intravenous urography (IVU) to demonstrate the presence of radioopaque renal or gallstones and to assess the adequacy of bowel preparation;  To detect calcification or abnormal gas collections, e.g. abscess;  Alimentary studies using barium preparations. MUSCULOSKLETAL DISEASES:  Fractures and dislocations.  Serious injury or foreign bodies.  Pathology e.g. rheumatoid arthritis.  Trauma or pathology. Contrast agent studies Conventional Radiograph Limitations: 1. Superimposition. 2. Inability to distinguish soft tissue (poor contrast). 3. Radiography is qualitative rather than quantetive. These limitations lead to need for better modality, which is………… B/ COMPUTED TOMOGRAPHY  CT= Computed Tomography  Image formed using a rotating thin beam(s) of ionizing radiation  Image “slices” reconstructed by computation  The image formed is related to the subjects density  Image display on computer or multiple films  New technology is multislice helical scanner Axial CT Brain  A patient head scan performed on the first clinical CT scanner. [Figure supplied by ImPACT (www.impactscan.org), St George’s Hospital NHS Trust, London, and reprinted with permission.] Comparison of CT head images acquired on (a) one of the first CT scanners and (b) the GE LightSpeed VCT 2005. Coronal view Imaging Planes  Think of large sheets of glass cutting through the body in various ways  Horizontal/transverse  Vertical/longitudinal  Coronal  Sagittal  Oblique  Axial  Why CT required?  Limitations of Plain radiographs  ?  ?  ?  The main advantages of CT over conventional radiography  The elimination of superimposed structures.  The ability to differentiate small differences in density of anatomic structures and abnormalities, and  The superior quality of the images CT ADVANTAGES  CT Scanner  X-Ray modality used to the body in cross section  Used to determine  extent of trauma  location and type of tumors  status of blood vessels  pre surgical planning