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“What Test is Best” Choosing Radiology Exams in Emergency Settings

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Presentation on theme: "“What Test is Best” Choosing Radiology Exams in Emergency Settings"— Presentation transcript:

1 “What Test is Best” Choosing Radiology Exams in Emergency Settings
Dr. C. Freeman PGY-4 Dr. A. Olivier

2 Objectives To provide a guide to selecting the appropriate imaging studies in common emergency settings Please note: the goal of this talk is NOT to review how to read radiological exams.

3 Modalities Plain Films Ultrasound
Based on differential attenuation of X-rays by different tissues Ultrasound Uses sound waves Real time Very accessible No radiation

4 CT Computer reconstruction of 2 dimensional X-ray data
reconstructions in any plane Accessible, fast

5 WHAT IS A “SPIRAL CT”?????? Helical movement (patient and gantry move at the same time) Almost all modern CT’s are helical Exceptions: Head CT, High Resolution CT of the chest

6 Soft tissue differentiation (e.g. Soft tissue tumors)
MRI Soft tissue differentiation (e.g. Soft tissue tumors) many other specialized indications (e.g. acute stroke) limited accessibility, expensive Expanding role in many clinical situations

7 CHEST “the patient who is short of breath”
Common Causes… CHF, atelectasis, pneumonia, pneumothorax, pulmonary embolus start with a Chest X Ray

8 Atelectasis Left diaphragm silhouetted Left diaphragm now seen

9 Complete Collapse

10 Inspiration-expiration may increase sensitivity
Pneumothorax Inspiration-expiration may increase sensitivity

11 Pneumothorax

12 Tension pneumothorax ***EMERGENCY
place needle in 2nd intercostal space (mid clavicular line)

13 Pneumonia Air bronchograms Silhouette sign

14 Pneumonia: Air Bronchogram

15 Congestive Heart Failure

16 Pulmonary Emboli CXR V/Q Scan CT Pulmonary Angiogram
non specific, non sensitive V/Q Scan useful if high probability or low probability CT Pulmonary Angiogram

17 CXR: HAMPTON’S HUMP Chest X-ray not useful to rule in or rule out PE
BUT may help to find other cause of SOB (e.g. CHF)

High probability: Treat (anticoagulate) Low probability: unlikely to have PE Intermediate Probability: ??? CT Angiogram


20 Aortic Dissection CT Trans-esophageal echo

21 CT Reconstruction: Aortic Dissection

22 GI/GU Again, begin with a plain film
Remember utility of upright and decubitus films for identifying free air and air fluid levels Often move on to another exam depending on plain film findings

23 Free Air ^^^ ^ Upright Chest X-Ray is the most sensitive test for free air

24 Free Air: Decubitus View

25 FREE AIR we see both sides of the bowel wall “Riegler’s sign”

26 Plain Films CT IVP (ultrasound sometimes useful…e.g. if pregnant)
Renal Colic Plain Films CT IVP (ultrasound sometimes useful…e.g. if pregnant)

27 Ureteric calculus note how well a calcified stone is seen on plain films.

28 IVP Shows function and obstruction HOWEVER…largely replaced by CT
“Left flank pain” IVP Shows function and obstruction HOWEVER…largely replaced by CT

29 Renal Colic: CT Now Preferred Modality

30 RLQ Pain, Fever, WBC ……? Appendicitis
Plain film of limited utility may see appendicolith Ultrasound No radiation In females, can also see adnexa Especially good in thin patients CT If overweight

31 ..? Appendicitis RLQ PAIN appendicolith

32 Appendicitis: CT

33 “distended abdomen with obstipation and peritoneal signs”
Bowel Obstruction start with a plain film supine and upright views lateral decubitus if upright not possible

34 Small Bowel Obstruction
Multiple air-fluid levels distended bowel loops note the value of upright (or decubitus) view

35 Large Bowel Obstruction: Contrast Enema
Confirms the site of abrupt narrowing at the splenic flexure (large arrow)

36 Bowel Obstruction…after the plain film
Depends on the clinical scenario May monitor patient May go directly to the Operating Room May proceed to CT helps to define location and cause of obstruction

37 Pancreatitis Clinical/Biochemical Diagnosis
Ultrasound to identify cause (i.e. biliary stones) CT is used to identify and follow complications ***NOT TO DIAGNOSE Will MISS diagnosis in 30% of cases

38 Scrotal Pain History and Physical first
May proceed directly to the OR Ultrasound is the modality of choice Can identify status of blood supply

39 Testicular Ultrasound

40 RUQ Pain Ultrasound is the modality of choice
CT can miss acute cholecystitis or cholelithiasis

41 Ultrasound: Cholelithiasis

42 Neuroradiological Emergencies
Start with a CT **Except cord compression May ultimately need an MRI

43 Clinical Settings Seizures Trauma Headache Stroke

44 Seizures: CT---Neoplasm

45 Seizure: MRI---Neoplasm

46 CT: Stroke Some advanced CT techniques …”CT Perfusion” helpful
In the USA, many centers MRI is the initial exam Some specialized MRI Techniques can identify brain at risk (“penumbra”) vs. dead brain

47 CT Intra - Cranial Bleeds Subarachnoid Hemorrhage Subdural Hemorrhage
Epidural Hemorrhage

48 CT: Subarachnoid Hemorrhage

49 Epidural Hematoma

50 Subdural Hematoma

51 SPINE Emergencies

52 C-Spine Trauma Plain films: CT MRI
If minor trauma, plain films including flexion and extension views can suffice CT For significant injury From skull base to T1 Sagital and coronal reconstructions MRI Unexplained neurologic deficit Unconscious for prolonged period of time

53 Normal C-Spine with CT Axial Sagital Coronal

54 Hangman’s # Axial Sagital

55 C5-6 dislocation Axial Sagital

56 MR Angiogram C5-6 dislocation with Left Vertebral Artery dissection

57 Suspected Spine Infection
Plain films may be diagnostic Do not demonstrate compression of thecal sac MRI is optimal CT can be adequate Fluoroscopic or CT guided aspiration/biopsy We follow these cases with MRI

58 Discitis Discitis, Sagital Coronal Axial

59 Discitis, osteomyelitis prevertebral & epidural phlegmon

60 Cord Compression: MRI Metastatic Melanoma

61 Spine Emergencies: Summary
MRI is generally the best exam for the spine CT is excellent in many indications Plain films have a limited role MRI access is quite limited, so we compromise and do a lot more CT

62 MSK

63 Fractures Remember that acute fractures may not be seen on plain films for up to days. Bone scan is more sensitive

64 Plain Film: Ankle Fracture

65 Sacral Fracture: CT

66 ? Septic Joint Plain film may be suggestive MUST aspirate joint
This is a medical emergency

67 Necrotizing Fasciitis
Ultimately a clinical diagnosis Plain Films Gas in the soft tissues MRI For surgical planning CT may give a false negative (not sufficient to rule out diagnosis)

68 Summary Almost always start with the plain film
There are some exceptions Neurological Emergencies If you are unsure as to what test is appropriate…talk to the Radiologist

69 Thank you!! Dr. C. Freeman Dr. A. Olivier

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