1. Petra Lewis MD Professor of Radiology and OBGYN Geisel School of Medicine at Dartmouth

2. Learning objectives  Understand the meaning of the silhouette and sign signs  Understand how these concepts can be applied in the diagnosis and localization of pneumonias  See how viral pneumonias differ in appearance  Describe how pleural effusions appear on chest radiographs on different views  Understand how the appearance of effusions varies in empyema and hydropneumothorax  Understand the factors affecting the risks of medical radiation and how they can be reduced.  Calculate the risks to a real patient from his medical radiation exposure during a single clinical episode

3. What questions/difficulties did you have arising from the case

4. Pneumonias

5. Silhouette sign

9. RLL pneumonia

21. Pleural effusions

22. Pleural Effusions  How much fluid do you need to see on A PA CXR? A lat CXR? A supine CXR? A CT scan?  How else can you visualize pleural fluid?  Characteristics of fluid vs consolidation?

23. Small effusions

25. Decubitus views

28. Supine pleural effusions

34. Radiation Risk

35. Radiation risk  What factors affect how much risk patients are at from medical radiation?

36. Relative risks of exams AXR Barium enema Bone scan CT abdomen/pelvis CT head CT pulmonary angio CXR (PA ) CXR (PA and lat) Low dose CT chest Lumbar spine Mammogram Myocardial perf PET FDG scan UGI Wrist radiograph

37. Radiation Equivalents Average background = 3mSv StudyPeriod natural radiation Wrist radiograph 0.1 d CXR (PA ) 2 d CXR (PA and lat) 12 d Mammogram 2 m AXR 3 m Lumbar spine 6 m Low dose CT chest 7 m CT head 8 m UGI 1.7 y Bone scan 2.0 y Barium enema 2.7 y Myocardial perfusion 3.1 y CT abdomen/pelvis 4.7 y PET FDG scan 4.7 y CT pulmonary angio 5.0 y Metter et al. 2008, 248, 254-263.

38. Case study HT abdominal CT 27 year old with complicated pancreatitis

40. HT Radiology Studies 12/7/06-2/6/07 CXR28 KUB11 CT chest1 CT head1 CT abdo-pelvis19 Fluoro1 minute

41. What is his increased risk of dying of a malignancy due to his radiation exposure during this hospital stay?

42. How much radiation did HT receive? Scan#Exposure/scan mSv Total CXR280.02 KUB111 CT chest18 CT head12 CT A/P1910 Fluoro1 minute0.1 /min TOTAL

43. So our patient received an estimated dose of ? mSv

44. Cancer induction rates  8% fatal cancers per Sv (1000 mSv) = % fatal cancers risk for HT  Fractionation reduces risk by 50% = % fatal cancers risk for HT  Younger patient (<40) doubles risk (much higher for young children) = % fatal cancers risk for HT

45. Cancer induction rates  Lifetime risk of fatal cancer 24% males, 20% females = /24 x 100% increased risk of dying of a cancer from his hospital exposure =  Note – his risk of developing any type of cancer is about twice this (fatal and non- fatal)

46. How can we reduce risk?

47. Appendix

48. Learning Objectives from CORE 1  Review CXR anatomy including the location of the lobes of the lung and their relationship to fissures  Be introduced to the American College of Radiology (ACR) appropriateness criteria for imaging  Learn the indications for chest imaging in patients presenting with upper respiratory tract infection symptoms.  Learn the radiographic presentations of typical alveolar pneumonias in different lobes of the lung.  Understand the concepts of “silhouette sign” and “spine sign” and how they can be used to localize abnormalities on chest radiographs.  Understand the term “air bronchograms” and the significance of this sign.  Learn how some tumors can appear similar on imaging to pneumonia.  Be introduced to the typical radiographic appearance of PCP pneumonia, and other opportunistic and atypical pneumonias and how they differ radiographically from typical bacterial and lobar pneumonias  Understand the meaning and appearance of “ground glass” opacities on chest radiographs and CT scans.  Understand the use and limitations of portable radiographs in the ICU.  Learn the imaging features of ARDS  Acquire a basic understanding of patient radiation doses from common examinations and how we can try to limit them.  Learn the common imaging features of various types of pleural effusion including simple, hydropneumothorax, empyema and loculated pleural fluid collections (“pseudotumors”).  Understand how pleural fluid appears differently on erect and supine radiographs.  Learn when image guidance can help in the drainage of pleural fluid.