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Easily Missed Findings in Emergency Radiology

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Title: Easily Missed Findings in Emergency Radiology


1
Easily Missed Findings in Emergency Radiology
Case-based session 1 Brain
Diego B Nunez Jr. MD. MPH.
Clinical Professor and Chairman
Department of Radiology-Hospital of St. Raphael
Yale University School of Medicine
2
OBJECTIVES
  • Illustrate frequent diagnostic errors when
    interpreting emergent brain imaging using common
    clinical scenarios Learning from
    mistakes
  • Review the diagnostic clues and risk management
    pointers that can minimize perception and
    interpretation errors and their consequences

3
Errors in Radiology
  • Perceptual errors
    False negative
    interpretation or misses (finding not seen)
  • Cognitive/interpretation errors
    Failure to
    recognize the ramifications or significance of a
    finding. Usually the result of poor
    judgment, incomplete knowledge or technical
    factors

4
Which of the following representsthe most common
type of error when interpreting emergent brain CTs
  • The finding is missed
  • Overeading/misinterpresting a
    finding as abnormal
  • The finding is identified but passed as
    normal or insignificant
  • The finding is identified but attributed to
    the wrong disease

5
Perceptual errors are most common
Errors in Radiology
Berlin Hendrix, AJR 170863
Errors on Head CT typically result from
subtle perceptual misses rather than from
faulty interpretation of a finding once it is
recognized
6
This patient had a 24 hour follow up CT that
revealed an obvious infarct. Where will it be?
  • Left cerebellum
  • Pons
  • Left frontal
  • Right parietal

7
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8
10/31/08
Missed MCA clot
Left frontal opercular infarct
11/1/08
9
Post Traumatic (Neck hyperextension) Right
Internal Carotid Dissection and MCA Infarct
10
Why do we miss pertinent findings?
  • Incomplete clinical information
  • Subtle, inconspicuous finding
  • Coexisting findings/lesions
  • Unexpected or unusual presentation of disease

Factors related to the interpreter !
A. Satisfaction of search error (multiple
abnormalities) B. Inadequate search error (no
systematic approach) C. Errors of analysis
(lack of knowledge)
Errors of omission and communication
11
Indication Trauma
12
Convexity midline fracture, epidural hematoma
and unsuspected right frontal contusion
13
Indication CVA
Infarct in opposite side than suspected. CVA is
not enough
14
Why do we miss pertinent findings?
  • Incomplete clinical information
  • Subtle, inconspicuous finding
  • Coexisting findings/lesions
  • Unexpected or unusual presentation of disease

Factors related to the interpreter !
A. Satisfaction of search error (multiple
abnormalities) B. Inadequate search error (no
systematic approach) C. Errors of analysis
(lack of knowledge)
Errors of omission and communication
15
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16
28 y.o. patient with severe craniofacial trauma
Acutely expanding epidural hematoma
17
isodense subdural hematoma
18
28 y.o. front passenger involved in major
collision. Depressed sensorium.
Glasgow score 6.
Hemodynamically stable
19
48 y.o. woman with increasing headaches for 2
days
20
Intracranial hypotension syndrome
  • Orthostatic headaches and neck pain, nausea and
    vomiting. Diverse origin
  • Most cases related to CSF leak (dural
    violation)

Thick dura without leptomeningeal enhancement
Downward displacement of the brain and
enlarged pituitary gland
Subdural fluid collections
21
Why do we miss pertinent findings?
  • Incomplete clinical information
  • Subtle, inconspicuous finding
  • Coexisting findings/lesions
  • Unexpected or unusual presentation of disease

Factors related to the interpreter !
A. Satisfaction of search error (multiple
abnormalities) B. Inadequate search error (no
systematic approach) C. Errors of analysis
(lack of knowledge)
Errors of omission and communication
22
64 y.o with left sided weakness
  • Suprasellar Meningioma
  • Right Pontine Infarct

23
57 y.o. ED patient with right sided weakness
24
3. Coexisting lesions Meningioma infarct
25
3. Coexisting lesions as a cause of perceptual
error
26
72 y.o. female found unconscious
27
Satisfaction of search errors
We stop the search after detecting the obvious
finding! The obvious captures attention and
decreases vigilance for more subtle abnormalities
  • Use automatic check lists
  • Systematic approach to image interpretation

28
Why do we miss pertinent findings?
  • Incomplete clinical information
  • Subtle, inconspicuous finding
  • Coexisting findings/lesions
  • Unexpected or unusual presentation of disease

Factors related to the interpreter !
A. Satisfaction of search error (multiple
abnormalities) B. Inadequate search error (no
systematic approach) C. Errors of analysis
(lack of knowledge)
Errors of omission and communication
29
4. Unexpected presentation of disease
Inadequate Search Error
  • Areas not often included in the search
    pattern in the emergency/on-call setting
  • Lack of checklist approach
  • Emphasize in resident education

30
Unexpected presentation of disease
Rotation/Posterior fossa artifact
31
Cognitive/interpretation errors
  • Failure to recognize the ramifications or
    significance of a finding.

32
The most commonly unrecognized lesion in emergent
neuroimaging is
  • 1. Facial fractures
  • 2. Subdural hematoma
  • 3. Cervical spine fracture
  • 4. Missed or undercalled stroke

33
The most commonly unrecognized lesion in emergent
neuroimaging is
  • 1. Unrecognized hemorrhage 15
  • 2. Missed or undercalled stroke 22
  • 3. Cervical (spine/airway) lesion 14
  • 4. Missed facial fracture 11

Branstetter et al Articles from RSNA 2005
34
Only one of these patients has an infarct
1
2
3
5
4
4
35
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36
Early CT signs of ischemia
Dense MCA
Insular ribbon
Hypodense Basal ganglia
37
65 y.o. male patient with Rt. arm weakness and
facial droop with mild impairment of language
expression
Detection facilitated by soft-copy visual review
at a PACS workstation with variable non-standard
window and center level settings
38
Why do we miss pertinent findings?
  • Incomplete clinical information
  • Subtle, inconspicuous finding
  • Coexisting findings/lesions
  • Unexpected or unusual presentation of disease

Factors related to the interpreter !
A. Satisfaction of search error (multiple
abnormalities) B. Inadequate search error (no
systematic approach) C. Errors of analysis
(lack of knowledge)
Errors of omission and communication
39
1
  • Necrotizing encephalitis in adults
  • Acute confusion, seizures, fever, coma
  • Speech impairment (temporal lobe)
  • Typical distribution temporal lobes, insula,
    orbitofrontal region and cingulate gyrus
  • 75 mortality if untreated. Early Dx.

Patient 1 Herpes Simplex Encephalitis (Type 1)
40
Brain abscesses
Patient 3 35 y.o. female with Crohns disease
who presents to the ED with 3 days history of
headaches and right sided weakness
41
Patient 4- 66 y.o patient with right hemiparesis
DX. Glioblastoma
42
Patient 5 MT Lung Ca initially dx. as infarct
43
THE FALSE POSITIVES
44
Meningioma mimicking epidural hematoma in
trauma patient
45
4 different ED patients- Only 1 has a significant
finding
3
1
2
3
4
46
1
Motion and positioning artifacts
2
False dense MCA sign
47
Patient 3 False Subarachnoid hemorrhage
3
  • Beam hardening non-uniform x ray beam
  • attenuation through uneven skull thickeness

48
4
49
4
Patient 4 Venous sinus thrombosis
50
23 y.o female patient brought to the ED after
seizures and rapid onset of aphasia
Superior Sinus Thrombosis Venous Hemorrhagic
Infarct
51
CT Delta sign
MR Delta Sign
High density triangle
  • Acute dehydration
  • Hypercoagulable states
  • Chemotherapy
  • Infection (sinus, meninges)
  • Pregnancy
  • Trauma

52
Other Frequently Missed Diagnoses in Emergent
Neuroimaging
  • Subarachnoid hemorrhage
  • Incidental aneurysms
  • Suprasellar mass/Skull base lesions

53
Other Frequently Missed Diagnoses in Emergent
Neuroimaging
48 y.o. female patient presents with acute onset
headache
54
Subarachnoid hemorrhage
Can be subtle
55
MVA. Minor head trauma?
Right frontal subarachnoid hemorrhage
56
Errors in Emergent Neuroimaging
  • Review of diseases
    Acute ischemia, SAH, small/isodense extraaxial
    collections, DAI
  • Specific locations
    Posterior fossa, skull base, interhemispheric
    fissure, and interpeduncular cistern
  • Common false
    motion, rotation, beam hardening artifacts, dense
    MCA

57
Avoiding errors Risk imaging pointers
  • Pay proper attention to clinical information!
  • Look at the images before reading prior reports
  • Be willing to take a second look, particularly
    when requested by a concerned clinician
  • Systematic approach to image interpretation Be
    aware of alternate presentation of disease and
    recognize the anatomic sites where lesion
    perception may be difficult, i.e. posterior fossa
    and skull base.

58
Avoiding errors Risk imaging pointers
  • Remember ! The diagnostic possibilities in
    emergent brain CT are relatively limited and we
    typically miss subtle findings
  • Significant on-call errors made by residents can
    be minimized by focusing our teaching on the
    perceptual manifestations of Neuroradiology
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