radiology.pdf

01 Introduction for Diagnostic Radiology Dr. Hosny A. Ghany  Aim of the course  Provide knowledge about the different diagnostic imaging modalities  Idea about the physical background of each diagnostic modality  The clinical applications of each modality...

01 Introduction for Diagnostic Radiology Dr. Hosny A. Ghany  Aim of the course  Provide knowledge about the different diagnostic imaging modalities  Idea about the physical background of each diagnostic modality  The clinical applications of each modality  The advantages and dis-advantage s of each modality  Other parts of the course  Idea about interpretations and application of imaging at different body systems  Example:  chest x-ray  Neuro-imaging  GIT imaging  Musclo-skletal imaging  Imaging modalities: 1- X-rays 2- Ultra sonography. 3- Computed tomography. 4- MRI. 5- Isotope scan. 6- PET CT 1- X-Rays    This picture of Roentgen wife’s hand, reportedly exposed on 22 December 1895  Basic X Ray Principles ‫ل‬ ‫ سبحان هللا ا عظيم‬، ‫سبحان هللا و بحمده‬ Investigations edited by COMT 1  Electromagnetic radiation spectrum  Which of the above examples of electromagnetic radiation has the shortest wavelength?  Cosmic rays  Which of the above has the lowest frequency?  Radio Waves  X Ray Tube  Modern x-ray device Investigations edited by COMT 2  How images obtained in plain radiography first was a cassette put under the patient in table with film inside its x ray machine turned on for imaging then film put in a processor to get images  In the era of digital imaging Special cassette put under the patient with sensor inside it X- ray turned on Electronic image well be available Changing from analog imaging to digital imaging  CR imaging (computed radiography)  A cassette based image storage system  Photo-sensitive material used within the cassette  Special reader used to clarify the images which sent to confuter  CR reader DR imaging  Direct digital imaging incorporates computer technology in image capture, display enhancement and storage of radiographic images  Advantages of DR imaging  Superior gray scale resolution  Reduce exposure to radiation  Increased speed of image viewing  Enhancement of diagnostic images  Effective education tool  DR Chest Imaging CR DR imaging plate Detector processed in a digital Reader Signal sent to computer Directly digital Viewed on a monitor seen immediately on computer Investigations edited by COMT 3   Indications for plain abdomen  Supine view  For urinary tract to detect stones  Abdominal calcifications  Abdominal gas pattern  Erect abdomen view  Suspected intestinal obstruction … for air fluid levels  Air under diaphragm Air fluid levels Air under diaphragm Intestinal obstruction Perforated viscus Plain X-ray KUB Air under diaphragm best seen at erect chest Image intensifier Investigations edited by COMT 4   Indications  For direct real time visualization  Used for radiological procedures like in:  Barium studies  Urological studies like ascending urethrogram and descending nephrostomy  Angiography of different organs  The most important indication for interventional radiology 2- Ultra Sound  Introduction  Use sound waves  High frequency than audible sound (20-20000 Hrz)  Variable velocity according to the medium  Characters of sound waves  Sound waves are:  Mechanical waves  Pressure waves  Longitudinal waves Sound is a pressure wave that propagates in gases, liquids or solids. The speed of sound depends on the density of the material. First use to measure distance Investigations edited by COMT 5  20 Hz 20 KHz Infrasound Acoustic Ultrasound Ultrasound waves need media to transmit through, Ultrasound is generated using transducers. so fluid is ideal but air cause Reflection from the interfaces complete reflex ion Transmission through the medium Ultrasound images are formed using reflected ultrasonic waves.  How to create a sonography image:?  Producing ultrasound waves Using a transducer (probe)  Receiving echoes Using the same transducer (probe)  Processing the echoes and forming the Image Using a computer  Advantages: US probes 1- Easy, non-invasive 2- Available 3- High soft tissue contrast.  Disadvantages: 1- Operator dependent. 2- Air reflection. 3- Difficult with obesity Investigations edited by COMT 6   Indications for US examination  First choice in abdominal examinations  Liver diseases including cirrhosis and tumors  Renal disease including stones/ back-pressure changes / inflammations and tumors  Spleen  Pelvic organs uterus and ovaries in female  Prostate in male  GB bladder and biliary disease: like GB stones/ biliary obstructions  Abdominal emergencies  Peritonitis  Internal hemorrhage  Abdominal LNs  Cysts anywhere are better detected by US  US in obstetrics has no alternative as it's the safest examination early pregnancy  Early pregnancy detect viability  Follow up of pregnancy baby movements / EDD presentation …..  Detection of ectopic pregnancy  Abortions  US less sensitive in diagnosis  Retroperitoneal structures due to overlapping abdominal gas Pancreatic region / can be seen in thin patients and well prepared Ureters except small parts near the kidney and near to the UB  Bowel difficult to visualized by US as gases contents result in complete reflexing of the sound waves / these include the stomach/ small and large bowel  Superficial US indications needs linear superficial probe  Examination of the thyroid glands: can differentiate solid nodules from cysts / also enlarged cervical LNs  Examination of the breast in females differentiate solid form cystic swellings  Examination of the testis: for testicular lesions and hydroceles  Musculo- skeletal indications: for any muscle hematomas or swellings N.B. Abdominal ultrasound must be the first and initial imaging study done at any abdominal condition ; before shifting to other investigation Normal Renal US Investigations edited by COMT 7  Renal pathology US Liver and GB Pregnancy DOPPLER U/S  Examination for blood vessels depending on flowing blood characteristics Investigations edited by COMT 8  Types of Doppler examinations  Continuous wave Doppler  Spectral Doppler or Duplex  Power Doppler 3- C.T.  Introduction  Means: Computed Tomography  Initially called CAT (computed axial tomography) as all examination in axial plane only  Now CT image the 3 planes (axial coronal and sagittal)  History  Nobel man... Godfrey Hounsfield with an early version of the CT scanner, then called the EMI Scanner. Investigations edited by COMT 9 Tomography Tomos = slice; Graphein = to write Definition - imaging of an object by analyzing its slices. History 1971 - first commercial CT (Sir Godfrey Hounsfield). 1974 - first 3rd generation CT. 1979 - Nobel price (Cormack & Hounsfield). 1989 - single-row CT. 1994 - double-row spiral CT. 2001 - 16-row spiral CT.  Introduction Continue..  In conventional X-ray imaging, the entire thickness of the body is projected on a film: structures overlap and are difficult to distinguish). One of the problems is the loss of information about depth.  Computed tomography (CT) is a method of acquiring and reconstructing the image of a thin cross section on the basis of measurements of attenuation. In comparison with conventional radiographs, CT images are free of superimposing tissues and are capable of much higher contrast due to elimination of scatter.  What is CT?  CT is a Medical imaging device which generates Cross sectional images used to aid in diagnosis of various diseases.  A CT Scanner is…  CT: Computerized Tomography  CAT: Computerized Axial Tomography  Spiral CT.  Multi-Slice CT or Multi-Detector.  CT Volume.  Slice / Cut  The cross sectional portion of the body which is scanned for the production of CT image is called a slice.  The slice has width and therefore volume.  The width is determined by the width of the x-ray beam. Investigations edited by COMT 10  Computed Tomography Components  Gantry.  X-Ray Tube.  Detector.  Table.  CT (Computed Tomography) Gantry – Patient Table- Computer System- Image Display  MDCT Multi-detector (Multi-slice) Investigations edited by COMT 11  Idea Multi-detector Single detector Idea Helical scan Single Multi  Modern MDCT start from dowel To 4-16-64 -128 slices And now reach 256 slice Scan time sub second Tissue thickness sub milltemeter Investigations edited by COMT 12  CLINICAL APPLICATION OF MDCT  MDCT of the Abdomen  MDCT of the Cardiovascular System  MDCT of the chest  MDCT of Musculoskeletal system  MDCT of Head and Neck  MDCT of the Abdomen  MDCT of Liver and Biliary System  Renal MDCT  MDCT Angiography of the Abdomen  MDCT Colonography  MDCT of the Small Bowel  MDCT of the Pancreas  MDCT of Abdominal Trauma  Principles of Contrast media  Types of contrast: Oral and IV  Can CT abdomen done without contrast NO except in: Renal CT for calculi, intestinal obstruction ??  Oral preparation is important for bowel opacifications (so we can conclude about the wall  Post processing CT images  In all CXT examinations CT machine takes axial cuts  As we mentioned axial cuts represents slice of the tissues so in early CT machine s only axial cuts were available and so anatomical interpretations was difficult  With new advanced in CT machine especially in computers  There was availability f re -arrangements of axial slices into different planes  Image reconstruction  Anatomical  Coronal views  Sagittal views  Window ( images with different densities )  Like : lung and medistianl window in chest CT  Abdominal window in abdomen  Vascular MIP Investigations edited by COMT 13 CT Lung (pulmonary and mediastinal window) Sagittal and coronal CT Abdomen coronal sagittal Investigations edited by COMT 14  MDCT (Multi Detector Tomography) CT urography MDCT of the Urinary Tract CT urography 3 D image  CT angiography techniques  Before the advances in CT examination of the vessels anywhere doe by direct canlulation of the required vessel or by catheter and then inject contrast  Advances in CT especially in rapid time of examination ; enable to inject contrast material IV and then visualize the vessel wanted to examine by rapid series of CT images  Lastly reconstruction of CT images into anatomical view of the vessles Investigations edited by COMT 15  Cerebral angiography coronal MIP Sagittal 3 D with bone removal Carotid and cerebral angio  Lower limb angiography  In examination of lower limb vessels we need IV contrast injection by automatic injector  Timing of the contrast injection and beginning of examination  Rapid examination to follow contrast in vessels  Examination done in axial cuts then reconstruction mad e by machine computer MDCT Vascular Investigations edited by COMT 16  Different image reconstruction in lower limb angiography MIP coronal VR VR /bone MDCT Spine Sagittal reconstruction lumbar Axial Cuts lumbar  Preparation  Renal Function  Fasting Investigations edited by COMT 17  4- MRI Magnetic Resonance Imaging  Use high magnetic field Magnet 1 Tesla and more  No ionizing radiation  Shift of nuclei within the magnetic field  Image display Types of magnets Closed magnet Open magnet  Advantages of MR over CT  High soft tissue resolution so it gives better details in : * brain imaging between cortical sulci and deep white matter / early ischmic infarct  small brain lesions can be seen  in MSK imaging: can show ligaments of the knee ( ACL and PCL) / around shoulder ( supra-spinatous )_ and ankle  in abdominal an d pelvic imaging in detection and staging of tumors  Neuro imaging : Early vascular stroke / good differentiating between gray and white matter / evaluation of brain tumors  Early detection of lesions like MS  Muskulo-skleteal imaging : back pain Good in ligament tears Like ACL  Joint diseases  Newly indications include all body parts : abdominal / pelvic … as problem solving procedure  Who should not do MR  Patient with cardiac pacemakers  Metallic Clips : carotid / aortic  Cochlear implants  Patient with calustorphopia  Metallic material within patient clothes Investigations edited by COMT 18  MRI ( Magnetic resonance imaging) multi-planner coronal – axial Sagittal MRI Brian  MR sequences of the brain  Routine sequences  T1 best in detection of heamorrhage  T2 best in detection of edema of different types  FLAIR : Best for brain edema  Diffusion : ( DWI) used in suspected early ischmic infaction ( give positive results within 4 hours of the attack  Post contrast study ( especial type of contrast for MR used ( Gadolinium) used in : suspected brain tumor / MS for activity Ischemic infarction Investigations edited by COMT 19  MR of the spine  MR is best in diagnosis of disc lesions allover the spine  MR is best in diagnosis of cord lesions and intra-spinal lesions  MR important in diagnosis of bone marrow lesions like metastases  In trauma : CT is best in fractures but MR needed for evidence of cord compression and collections Axial and sagittal lumbar spine Normal sagittal cervical Cervical trauma if there is hazards from MR  No radiation Hazards.  precautions in presence of metallic stents and orthopedic screws Investigations edited by COMT 20  Gamma Camera  Isotope scanning of the body  Use : isotope material with especial labeled for each organ  Machine : gamma camera : especial machine to detect gamma rays arising fro the isotope material  Diagnosis depends on activity of the lesions Examples  1 Bone scanning : to detect bone metastases in cases of cancer use technechium  2- thyroid scanning : for assessment of thyroid nodule activity use : radio- activ e iodine  3- cardiac scanning : to detect myocardial viability oin cases of suspected mycoardial infarction Use thalium PET CT  Machine combined CT and isotope detector  PET Means positron emission tomography  CT computed tomography  Gives wide range of examinations The patient imaged twice : with isotope and then with CT in the same gantry then fusion of the images done computerized  Most important indications in oncology patient : for 1-detection of metastases in all tissues: 2- assessment of response in malignant t lesions after treatment Investigations edited by COMT 21  PET CT in neck mass Interventional radiology  Therapeutic procedure thorough radiology  Examples  Image guided biopsy  Embolization : injection of sclerotic material through specific vessels to occlude this vessels as in : post operative bleeding / presence of vascular lesions like AVM  Drainage procedure : 1localized abdominal collections or abscess  2 Treatment of liver abscess or lung empyema in specific cases  3-Biliary drainage as inoperable malignant jaundice to relive the symptoms or temporary before surgery to improve general condition  renal obstruction PCN ( percutaneous nephrostomy)  Treatment of cerebral strock to recanalize occluded vessel  Treatment of cerebral aneurysms  Radio frequency ablation : in hepatic - renal tumors or benign bony lesions Investigations edited by COMT 22  Patient Privacy And Medicolegality In Radiology  Patient’s Privacy  Patient Consent  Patient care Before imaging examination  Patient care During the course of the imaging  The ALARA principle  Clinical information's and correlation  Imaging in continuous advance  Know indication and contraindication for each procedure Patient privacy and medicolegality in radiology 1. Patient Consent: Before conducting any invasive procedure you should ensure your patient has given valid consent including warning the patient of relevant rare but serious side-effects, as well as common side-effects. Patient’s Privacy  Restricting physical access to authorized personnel only.  Computers must be password-protected and logged out when not in use so that patient information is not visible to people passing by.  Passwords should never be shared and should be changed regularly. Patient care Before imaging examination:  Purpose Patients should receive an explanation as to why the imaging is necessary.  Transparency The known limitations of examinations should be explained to the patient The ALARA principle  For patient safety no need for un-necessary patient exposure ( like repeated X-ray examinations without definite clinical need )  ALARA means As Low As reasonable Achievable ……. Radiation dose for the patient and works Clinical information's and correlation  It is very important to give the radiologist short history about the patient  The main aim of examination  If there is previous examinations done and the results  A good choice of the radiological procedure depends upon what we need to know Leave the radiologist tailored the optimal technique  Leave the radiologist tailored the optimal technique  Choice the best for patient diagnosis  Window of images  Contrast material or not  Further techneques Investigations edited by COMT 23  Know the indications and contra-indications of different techniques  You can discuss with the radiologist the best investigation of the patient in problematic cases  So we can avoid un-necessary techniques  We must know that radiology is costy for the hospital and patient  so we must choice the best and easier way for diagnosis Investigations edited by COMT 24