1. Primary Care Radiology Family Medicine Clerkship 2008-2009 Robin Schroeder, MD

2. Goals Students will Recognize the radiologist as a specialist consultant Develop an understanding of the basic modalities used in the evaluation of primary care patients

3. Objectives Students will be able to: Provide appropriate information to the radiologist when ordering a test Choose the initial best test for several common presenting complaints Describe the tests to the patient Integrate radiation exposure and cost when formulating the diagnostic plan

5. The Radiologist is your Consultant Call if you don’t know what test to order Provide specific patient history on the prescription or referral form What are you looking for or specifically trying to rule out? What is the next step when the test is normal, but the problem still exists?

6. Not all are created equal… Machines, scanners differ Tech quality varies Radiologist expertise varies

7. Modality Overview Plain radiography (plain x-ray) Computed tomography (CT or CAT scan) Ultrasonography (US) Magnetic Resonance Imaging (MRI) Nuclear Medicine Dual-Energy X-ray Absorpitometry (DEXA scan) Mammogram

8. Plain radiography (x-ray) X-ray beam, some is absorbed by patient, some exits and strikes a fluorescent screen Two-dimensional Air, fat, muscle/blood, bone (blackest to whitest)

11. Computed Tomography (CT) Rotating fan of x-rays beams Measures transmission through patient at thousands of points Presented as series of slices 10-100 times more radiation than plain film Good for bone detail, calcifications Can use contrast-IV or GI

12. CT and contrast Oral contrast creates distinction between organs such as the bowel and other structures since the contrast fills the bowel IV contrast allows the differentiation between blood vessels and other structures such as lymph nodes Also enhances lesions (tumors, etc)

14. right

15. Ultrasonography High-frequency sound waves are used to make images Send high-frequency sound into the pt. and assess the strength and time of returning echoes No ionizing radiation White echoes on black background-result of differences in density between tissues

20. Magnetic Resonance Imaging magnetic field applied to the body Some Hydrogen nuclei (i.e., protons) align with the strong magnetic field Radiofrequency pulses are applied and disturb the nuclei (they go out of alignment)

21. MRI Protons snap back producing a detectable rotating magnetic field that the computer reads Different tissues of the body (e.g., fat, muscle) realign at different speeds, so the different structures of the body can be revealed.

22. MRI Better contrast resolution than CT (differentiate between similar tissues) Good for soft tissues, marrow, ligaments, marrow edema No ionizing radiation

23. MRI T1-weighted images: fat is white or bright signal, water is dark T2-weighted images: fat is darker than on T1 and fluids, such as CSF, are brighter Bone is not as well seen on MRI

25. T1 weighted sagittal

26. T2 weighted axial

27. Nuclear Medicine Pt. receives radioactive material (short-lived) Attach radionuclide (technetium 99) to specific carrier compound (localize in specific organ) Concentration of radioactivity in a chosen organ, tissue of pathologic process Scintillation imager (or positron emission tomography-PET scanner) creates image of distribution of radioactive material (take images over time) Obtain an image of physiologic function

31. Mammography Screening mammogram: 2 views, craniocaudal and medial lateral oblique Diagnostic mammogram: performed when there are symptoms or to f/u a screening mammo Digital mammography: film camera vs. digital camera, more versatile, better for denser breasts (usually younger women)

34. DEXA scan (gold standard) Indications: estrogen deficient, on steroids, metabolic diseases, assess response to osteoporosis drug therapy, FH, low BMI, smoker… T score: compares BMD to young, nl. pt. 0=avg risk, -1=2xrisk, -2 is worse, etc. Z score: compares BMD to age matched nl. Bone Mineral Density (BMD)

37. Sample Charges X-ray foot$300 MRI foot$1,800 MRI lumbar spine$3,000 Pelvic and transvaginal$1,400 ultrasound DEXA scan$450 Screening mammo$300 Diagnostic mammo$380

38. Case # 1 45 y.o. woman presents with 3 week history of right foot pain when walking What else do you want to know? Do you order a test?

39. Stress/Insufficiency Fractures Clinical setting is highly suggestive Stress: new athletic activity or repetitive activ. Insuff: osteoporosis, radiated bone, etc. Radiography specific, but not sensitive Negative initially 60-82% of the time Bone scan MRI

43. T1

44. Case # 2 48 y.o. woman with long history of ankylosing spondylitis presents with several months of left-sided low back pain that she attributed to the AS. Now she has severe pain in her whole left leg What do you want to know? Do you order a test?

45. Low Back Pain One of the most common problems in the US Usually self-limited: improves with conservative treatment Does not warrant any imaging studies for 4- 6 weeks

46. LBP-consider MRI Radiculopathy-not responding to conservative treatment History of cancer Unexplained fever or weight loss Prolonged use of corticosteroids, osteoporosis Focal neurologic deficit is progressive or disabling

47. LBP-consider x-ray Recent significant trauma Osteoporosis Age over 70 Tenderness to palpation over vertebrae

49. Table 1. Diagnostic Work-up for Initial Evaluation of Low Back Pain Possible cause Key features on history or physical examinationImaging*Additional studies* Ankylosing spondylitis Morning stiffness; improvement with exercise; alternating buttock pain; awakening because of back pain during the second part of the night; younger age Anteroposterior pelvis plain radiography ESR and/or CRP, HLA-B27 CancerHistory of cancer with new onset of low back pain MRI ESR Unexplained weight loss; failure to improve after one month; age older than 50 years Lumbosacral plain radiography ESR Multiple risk factors present Plain radiography or MRI ESR

50. Cauda equina syndrome Urinary retention; motor deficits at multiple levels; fecal incontinence; saddle anesthesia MRINone Herniated discBack pain with leg pain in an L4, L5, or S1 nerve root distribution; positive straight-leg- raise test or crossed straight-leg-raise test None Symptoms present longer than one month MRIConsider EMG/NCV Severe or progressive neurologic deficits Progressive motor weakness MRIConsider EMG/NCV Spinal stenosisRadiating leg pain; older age; pseudoclaudication is a weak predictor None Symptoms present longer than one month MRIConsider EMG/NCV

51. Vertebral compression fracture History of osteoporosis; use of corticosteroids; older age Lumbosacral plain radiography None Vertebral infectionFever; intravenous drug use; recent infection MRIESR and/or CRP CRP = C-reactive protein; EMG = electromyography; ESR = erythrocyte sedimentation rate; HLA = human leukocyte antigen; MRI = magnetic resonance imaging; NCV = nerve conduction velocity. *-Level of evidence for diagnostic evaluation is variable. Adapted with permission from Chou R, et al. Diagnosis and treatment of low back pain: a joint clinical practice guideline from the American College of Physicians and the American Pain Society [published correction appears in Ann Intern Med. 2008;148(3):247-248]. Ann Intern Med. 2007;147(7):481.

52. Case # 3 21 y. o. female college student with history of “functional” ovarian cysts presents with two month history of pelvic pain What else do you want to know? Do you order a test?

53. Additional Information Sexual history Fever Pregnancy test Re-scan? Follow-up

55. Case #4 40 y.o. female with a history of increasing indigestion over the past year with burping, occasional rt. upper quadrant pain and frequent nausea after eating What else do you want to know? Do you order a test?

58. Next test hepatobiliary iminodiacetic acid (HIDA) – cholescintigraphy Radioactive tracer collected in gallbladder CCK administered to cause contraction of the gallbladder, ejection fraction measured Under 40% considered abnormal

59. Case # 5 25 y.o. male medical student with increasing headaches since starting medical school. He thought the headaches were from stress, but it has been three months and now he is waking up with the headache and has some nausea. What else do you want to know? Do you order a test?

60. CT, MRI with or without contrast?! CT would be better to see a bleed or if you were looking for an abnormality of the bone MRI is better for soft tissue (like the brain and possible tumor) IV contrast allows better visualization of neoplasms because the uptake of the contrast is different from surrounding tissue

61. astrocytoma