1. BASIC CONCEPTS IN DIAGNOSTIC IMAGING Dr Mohamed El Safwany, MD.

2. Intended learning outcome The student should learn at the end of this lecture Basic concepts in radiological Imaging.

3. Outline Introduction X-Rays Fluoroscopy CT MR Innovative Modalities

4. Modalities Available in Radiology Plain Film / X-Ray/Mammography Fluoroscopy Ultrasound CT MRI Nuclear Medicine/Molecular Imaging Angiography/Interventional

6. X-Rays Discovered in 1895 and still used today Most widely performed imaging exam X Rays are emitted and detected in cassette Cassette can generate either a film or a digital image Films are kept ‘on file’ or in a digital archive

7. Most Useful Applications for Plain X-Rays Chest Musculoskeletal Abdomen: limited usefulness

8. Fluoroscopy Utilizes X-Rays Real-time imaging Utilizes image intensifier Involves use of contrast agents

9. Main Uses of Fluoroscopy Gastrointestinal Imaging Genitourinary Imaging Angiography Other –Intraoperative –Foreign body removal –Musculoskeletal

10. Gastrointestional Fluoroscopy Esophogram/Barium Swallow Modified Barium Swallow/Dysphgiagram Upper GI Small Bowel Series Enteroclysis Contrast Enema Defecography

11. Single Contrast vs Double Contrast Single Contrast –Generally uses just thin Barium –Distends lumen with high density material –Easier for patient/less mucosal detail Double Contrast/Air Contrast –Thick barium coats lumen –Effervescent tablets ingested to distend lumen with air –Produces ‘see-through’ images with greater mucosal detail –Greater sensitivity for small lesions, polyps, ulcers

12. Single Contrast Barium Enema Double Contrast Barium Enema Single Contrast vs Double Contrast

13. Contrast Materials for GI Exams Barium Sulfate –Thick: used in double contrast studies –Thin: used in single and double contrast exams –Paste: mod Ba swallow and defogography Gastrograffin –Full stregnth: rarely used –Dilute

14. Gastrograffin Swallow Study Barrium Swallow Study Barium vs Gastrograffin

15. Barium Sulfate Most widely used Better images than gastrograffin ‘Chalky taste’ Peritonitis may develop if perforation If delayed transit, may form concretions in colon

16. Gastrograffin Water soluble Foul Taste Poor mucosal coating –Basically used for R/O obstruction Won’t cause peritonitis if perforation May cause severe chemical pneumonitis if aspirated Osmotic pressure draws fluid into bowel lumen –Progressive distention in small bowel obstruction –‘Therapeutic’ enema in constipation

17. Patient Factors in GI Fluoroscopy Ability to ingest contrast –In order to get high quality images, a relatively large volume of contrast needs to be ingested fairly quickly Mobility –Multiple positions required for GI exams, particularly double contrast exams. –Limited mobility = less diagnostic images Weight –Tables have weight limits –Requires maximal radiographic technique and exposure is often suboptimal

18. Esophogram or Barium Swallow Evaluates pharynx and esophagus Limited evaluation of stomach Double or Single Contrast Mucosal contour and Motility

19. Modified Barium Swallow AKA Dysphagiagram and at Carle “cookie swallow” Performed with Speech Pathologist Barium administered in various bolus consistencies ranging from liquid to solid Evaluates swallowing mechanism Evaluates for aspiration Performed on videotape

20. Modified Barium Swallow

21. Upper GI Exam Evaluates esophagus, stomach and duodenum Double or Single Contrast Can be combined with small bowel series Largely replaced by endoscopy and cross- sectional imaging Fairly insensitive

22. Small Bowel Series Patient drinks 2 cups of thin Ba Overhead films obtained at routine intervals The Ba column is followed through until it reaches the colon Transit time, mucosal contour, bowel loop distribution are evaluated. Insensitive for small masses

23. Small Bowel Series

24. Small Bowel Enteroclysis “Double Contrast Small Bowel Series NGT placed at duodenal-jejunal junction Ba injected followed by methylcellulose See-through appearance to small bowel Greater sensitivity for small masses and mucosal lesions Patient discomfort related to NGT and diarrhea

25. Contrast Enemas Barium or Gastrograffin Double contrast or single contrast Generally less sensitive than endoscopy Requires bowel prep to assess for mucosal lesions Requires some element of patient cooperation

26. Single Contrast Barium Enema Double Contrast Barium Enema Contrast Enemas

27. Defecogram Barium paste is inserted into rectum Patient is asked to defecate under fluoroscopy Ano-rectal and pelvic floor dynamics can be assessed Rectocele, intussusception, pelvic floor relaxation, stress incontinence

28. Genitourinary Fluoroscopy Cystogram Voiding cystourethrogram Retrograde urethrogram Hysterosalpingogram

29. Cystogram Usually in adult patients Looking for tear or intraluminal mass Catheter placed and bladder filled with contrast to capacity: usually 300-500 ml. Spot films obtained when full Post void film: usually overhead

30. Cystogram with Intraperitoneal Rupture Cystogram

31. Voiding Cystourethrogram VCUG Usually in children with history of UTI Searching for vesicoureteral reflux In males, evaluate for urethral abnormalities: posterior urethral valves Same as cystogram except when full patient voids under fluoro with spot films

32. Retrograde Urethrogram RUG Male patients Pelvic Trauma Post-infectious: STD- looking for stricture Different techniques Meatus occluded and contrast injected into urethra under fluoro

33. Retrograde Urethrogram RUG

34. Hysterosalpingogram Used to evaluate endometrial canal and fallopian tubes Infertility and uterine anomalies Dye injected into cervical os under fluoro Injection continued with goal to opacify the fallopian tubes and spill contrast into peritoneum

35. Musculoskeletal Fluoroscopy Fracture/Dislocation reduction Hardware placement in the OR Flexion/Extension views of c-spine Arthrography –May be performed in conjunction with MRI or CT

36. Techniques Relevant to MSK Radiology Radiography (routine and specialized views) CT MRI US Densitometry Interventional procedures (arthrography, percutaneous biopsy/vertebroplasty)

37. MRI—Sagittal Knee T1 Weighted MSK Radiology Vertebroplasty

38. Computed Tomography (CT) Cross Sectional imaging modality Mobile X-ray tube that rotates around a pt Slices of X-ray transmission data reconstructed to generate image Data displayed in multiple window settings (lungs parenchyma, bone, etc.) Density measurements/Hounsfield Units analyze chemical component of tissue HU: -150-0 = fat, 0 = water, 0-20 = serous fluid, 45-75 = blood, 100-1000 = bone/calcium

39. CT Contrast Agents Intravenous contrast---iodinated Differentiate blood vessels vs. vascular internal organs Enteric contrast---barium Differentiate bowel vs. intra-abdominal fluid/masses Rectal contrast Retrograde urinary bladder contrast

40. CT Applications Neuro-imaging -Acute head trauma, acute intracranial hemorrhage -Low sensitivity for early ischemic stroke, intracranial metastatic disease, white matter degenerative disease Head and Neck imaging -Soft tissue of neck, paranasal sinuses, temporal bone imaging, orbital wall imaging

41. CT Applications Body Imaging -Chest, Abdomen, Pelvis (with enteric and IV contrast) Pulmonary nodules, Renal Calculi (without contrast) Acute appendicitis (with enteric and IV contrast) Specialized protocols: -Liver masses, pancreatic tissue, renal masses, adrenal masses

42. CT Applications Acute Abdomen -decrease rate of false laparotomy procedures Trauma Spine Imaging (cervical, thoracic, lumbar) Other osseous structures (pelvis, extremities) Vascular Imaging -CT angiography--- i.e. coronary arteries

43. CT Axial, with oral contrast in stomach

44. CTPETPET/CT

45. CTA (CT Angiography) CT Cardiac Imaging The Power of CT

46. Magnetic Resonance Imaging (MRI) Multi-planar scanning Without ionizing radiation Images generated using powerful magnets and pulsed radio waves passing through the body Data from Pt’s body used to generate image Field strength of magnets 0.3-3.0 Tesla

47. MR Contrast Agents Intravenous contrast---Gadolinium chelate- based contrast agents Gadolinium is a paramagnetic lanthanide that is toxic as a free metal Contrast to evaluate BBB, intracranial edema and hemorrhage Novel agents being developed as tagged Monoclonal antibodies for Molecular Imaging

48. MR Applications Neuro-imaging -Excellent tool due to high soft tissue contrast resolution -Abundant water content of CNS allows for imaging soft intracranial tissue Head and Neck imaging -Multi-planar capability allows for monitoring extent of disease -Differentiating subtle soft tissue boundaries of head and neck

49. MRI Axial, T2-Weighted

51. MR Applications Body Imaging -Thorax: mediastinal, hilar, chest wall abnormalities Limited lung imaging due to artifacts New advances in breast imaging Potentials for cardiac MRI with coronary MR angiography

53. MRI Breast Imaging

54. MR Applications MSK Imaging - High sensitivity for neoplastic, inflammatory, and traumatic conditions of bone and soft tissue - T1-weighted---fluid collections and abnormalities in fatty marrow - T2-weighted---lesions in both marrow and soft tissue

55. MRI Sagittal, T1-Weighted

56. Innovative Modalities Constantly evolving face of radiology New contrast agents for CT and MR Molecular Imaging - Imaging molecular events---enzymatic activity, receptor binding, cellular events Interventional Radiology and Interventional Neuroradiology

57. Text Book David Sutton’s Radiology Clark’s Radiographic positioning and techniques

58. Assignment Two students will be selected for assignment.

59. Question Describe importance of Hysterosalpingeogram?

60. Thank You 60