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Ordering Radiological Exams

Ordering Radiological Exams. Alex Rybkin MD Assistant Clinical Professor of Radiology SFGH/UCSF Nancy Omahen RN MSN NP Referral Coordinator, Radiology SFGH. How to order? What to order?. (Assumed: imaging is clinically indicated). Motivation.

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Ordering Radiological Exams

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  1. Ordering Radiological Exams Alex Rybkin MD Assistant Clinical Professor of Radiology SFGH/UCSF Nancy Omahen RN MSN NP Referral Coordinator, Radiology SFGH

  2. How to order?What to order? (Assumed: imaging is clinically indicated)

  3. Motivation • “I never give accurate history to Radiologists: it biases them and makes me trust them less.”

  4. “Blinded” Radiologist False Negative Rate 37% For PCP Pneumonia!

  5. Radiology Studies Prevalence (Pre-test prob) PPV, NPV (Post-test prob) Sensitivity: x Specificity: y

  6. PCP Pneumonia Hx: Hypoxia in an AIDS patient with CD4 = 57 Result: PCP Pna Hx: SOB Result: ???

  7. Sens & Spec vary!(And it’s a good thing) • Clinical situation • Experience • Ability/Training • Adaptation to technique • Techs • Hardware • Display methods

  8. Why Radiologist is not a tool, but a CONSULTANT • Results not binary • Multiple signs and findings • How to combine prevalence info with complex results • Most important: Radiologist has a brain

  9. Don’t Blind Your Radiologist • Think Radiologist as a consultant • Invest time and effort • Help us help you • Summarize signs/symptoms/history • Tell us what you want to know • ICD9 (so we can bill)

  10. Do we need clinical info? • 2 schools of thought: • Radiologists: We need it, but we are not going to get it • Non-radiologists: They don’t REALLY need it REALITY: Not getting enough specific information

  11. Status Quo • Chest study: “CP”, “SOB” • Abdominal study: “Abdom Pain” • Brain study: “HA”, “Weakness” Useless

  12. Example of CT e-referral sent by PCP(sent the same information for abd/pelvis CT request) • Diagnostic Question: R/O malignancy • History: Constitutional Symptoms Useless

  13. Status Quo • Scrotal Ultrasound: “R/o Hernia” Misleading

  14. Why “Rule Outs” are EVIL • Take us down the wrong path

  15. “R/o Uterine Fibroids vs Enlarged Prostate” Crohn’s disease with “creeping fat” producing a subtle mass

  16. Why “Rule Outs” are EVIL • Take us down the wrong path • Make us second-guess you

  17. R/o Appendicitis

  18. Why “Rule Outs” are EVIL • Take us down the wrong path • Make us second-guess you • Make Radiologists waffle (cannot prove a negative) • Really bad NPV • Limitations of technique (search) • “The hardest thing to find is the one that’s not there”

  19. Why “Rule Outs” are EVIL They will be rejected by billing & WE DO NOT GET PAID!! Diagnosis with: • R/O diagnosis • MVA • GSW

  20. Broken lines of communication • Lack of understanding by Providers of what Radiologists need • Roadblocks to info access • Hybrid written/digital ordering • Lack of unified repository of information • Lack of continuity of care Need collaboration within the system!

  21. “But how do I choose the right study?”

  22. Heuristic vs Perscriptive Approach • “Heuristics are rules of thumb, educated guesses, intuitive judgements, or simply common sense” -- Wikipedia • “Heuristics stand for strategies using readily accessible, though loosely applicable, information to control problem solving” – Perl, J et al

  23. Heuristic #1 • If you don’t know how to proceed, don’t guess, ask a Radiologist. • You can also call the Radiology Nurse Practitioner- x4407

  24. On the Menu: Plain Films Fluoroscopy Ultrasound CT (Computerized Tomography) MRI (Magnetic Resonance Imaging) Nuclear Medicine/PET CT Angiography

  25. ACR Appropriateness Criteria • acsearch.acr.org

  26. Choosing a study • Comparative studies • Consensus • Usefulness • Do no harm • Availability • Expense • patient • system

  27. Heuristic #2 • Use step-wise approach • Start with inexpensive, less risky studies • Escalate to more advanced studies as needed • No shotgun please!

  28. Imaging Costs (facility fee) • CXR 1 view $199 • Ultrasound abdominal $627 • CT abdomen with contrast $2279 • MRI brain with and w/o gad $7875

  29. Plain Films • Economical • Readily available • Quick • Informative • Good place to start

  30. Chest X-Ray • First-line study of the chest • Varieties: AP, PA & lateral, decubs • PA & lateral: best quality • AP: standby for immobile patients, portable studies • Decubs: eval pleural effusion

  31. Heuristic #3 • Radiological investigation of a Chest problem should always start with a CXR

  32. KUB & Abd series • KUB: supine abdominal film • Evaluation for obstruction • Abnormal calcifications (kidney stones) • Abd series: KUB, upright chest, +/- decubs • Obstruction • Calcifications • Pneumoperitoneum • Further eval: CT

  33. Heuristic #4 • Unless looking for obstruction, don’t bother with KUB

  34. Extremity Films • Good for broken bones, lesions • Very limited Soft Tissue info: effusions, sq emphysema, foreign bodies • For better definition of bone: CT • For better definition of soft tiss: MRI • For foreign bodies: CT or US

  35. Heuristic #5 • Plain films are more valuable than MRI for bone problems! (Known limitations: osteomyelitis, stress fractures, etc)

  36. General CT considerations • Quick • Available • Relatively Affordable • Problems: • Radiation (children, pregnancy) • Patient Size limit 450 lb • Patient Motion • Pt with ESRD

  37. Radiation Exposure • Up to 2% of cancer estimated due to CT. • Brenner et al, NEJM 2007

  38. Heuristic #6 • As Low As Reasonably Attainable (ALARA) • US or MRI in children and pregnant women

  39. CT IV Contrast • Benefits: • Better contrast in soft tissues • Better delineation of tissue types • Better sensitivity for tumors/abscesses • Risks • Kidney damage (eGFR < 60) • Allergic reactions • Fluid overload

  40. IV Contrast (cont) • Need eGFR/Cr within 30 days • eGFR < 15 NO CONTRAST • eGFR bet 15 and 60 • Consent • Hydration • Bicarb (Visipaque, N-AC(mucomyst) not effective)

  41. Allergic Reactions • Hx of life-threatening reactions is an absolute contraindication for contrast • Important to know if pt has had prior reaction to intravenous contrast- screen pt for allergies! • True allergy- anaphylactic (Type I reactions) or mild (delayed Type 4). • For mild reactions: premedicate • Call CT for protocol x8069

  42. Head CT • Trauma • Neurosurgical/Neurological Emergencies • For detailed exam: MRI • Contrast: • to better characterize abnormalities seen on noncon • Suspected tumor, abscess etc • HIV

  43. Spine CT • Trauma • Acute Abnormalities • Chronic Abnormalities: MRI • Spine compression: MRI • CT myelogram when MRI not possible

  44. Chest CT • Routine Chest CT: noncon, 2.5 mm cuts, no skips • Good for masses, nodules, effusions • Give contrast for better imaging of mediastinum, pleura • High Res CT (HRCT): noncon, 1mm cuts, 1-2 cm skips • Interstitial lung disease, airways disease • Expiratory images, prone images • PE Protocol CT: with contrast, 1.25 mm cuts, no skips, bases and apices excluded • PE, vascular abnormalities

  45. Abdominal CT • Routine Abd/Pelvis • Most abdominal indications • Oral, +/- Rectal and IV contrast • Renal Stone protocol • noncon, thin cuts • Specialized organ protocols: • talk to you friendly Radiologist

  46. Heuristic #7 • For most abdominal problems requiring imaging, CT is most bang for the buck

  47. Liver studies • Liver Protocol CT: 3 phases • Arterial, Portal, Delayed • Alternative-- US: • less radiation, less sensitivity • useless in proven cirrhosis • Alternative MRI: • better specificity, less availability

  48. Abdom CT: Enteric Contrast • Not absorbed • Minimal risks • Neutral vs Positive contrast • Neutral (hypertonic): better bowel wall definition • Positive: better for perforation, abscess

  49. MSK CT • Exquisite definition of fractures • Usually for preop planning • For most problems rely on plain films and MRI (bone vs soft tissue problems)

  50. Ultrasound • Fast, Cheap, NO RADIATION • Limitations: • Operator dependent • US does not go through bone, air • Labor intensive • Small field of view • Typical indications: RUQ pain, Ob/Gyn imaging, Thyroid, Vascular imaging

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