Relationship of Image Quality to Decision Accuracy for ARVCD in MRI

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Relationship of Image Quality to Decision
Accuracy for ARVC/D in MRI

• Elizabeth Krupinski, PhD
• Theron Ovitt, MD
• University of Arizona

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ARVC/D

• Arrhythmogenic right ventricular cardiomyopathy /
  dysplasia
• RV muscle replaced by fatty /or fibrous tissue
• Progressive ? arrhythmic death

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ARVC/D

• Most common ? 15 40
• Premature ventricular beats
• Ventricular tachycardia left bundle branch block
  morphology
• Sudden cardiac death uncommon but may be 1st sign
• Familial 30 50 cases

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Use of MRI

• Differential diagnosis - RV outflow tract
  tachycardia (RVOT)
• Characterizes fat in free wall by ? signal
  intensity
• Shows contraction abnormalities of RV

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Rationale

• Acquisition protocols vary
• Image quality not studied
• Artifacts not studied
• Reader performance not studied

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Cases

• 45 static MRI films
• ARVC/D registry UofA
• 7 met Task Force criteria
• 31 suspected clinical signs
• 7 imaged other reasons

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Readers

• 12 experienced cardiac MRI radiologists
• 1 cardiologist expertise in MRI
• 13 different institutions US, Canada, Europe

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Reading Protocol

• Cases ? randomly 4 groups
• Mailed independently
• 1 month between mailings
• Pre-formatted response sheet
• 6 clinical questions
• 3 image quality questions

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Image Quality
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Motion Artifacts
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Other Artifacts
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IQ Motion Artifacts

• Inverse relationship
• No ? mild good ? excellent
• Moderate ? severe fair ? poor
• X2 159.413, df 9, p lt 0.0001

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IQ Other Artifacts

• Inverse relationship
• No ? mild good ? excellent
• Moderate ? severe fair ? poor
• X2 135.82, df 9, p lt 0.0001

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ARVC/D Decisions
X2 6.756, df 2, p 0.034
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Decisions x IQ
X2 11.74 df 9 p 0.2281
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Reader Agreement

• 1/45 (2) complete agree
• No ARVD
• All agree absent
• Kappa 0.052
• Very low
• Poor discriminability

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Other Indicators

• If present gt ? ARVC/D present
• Fat in myocardium
• Enlarged RV chamber size
• RV configuration abnormal

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Other Indicators

• No relationship with ARVC/D present
• LV chamber size
• Myocardium fat location
• Anterior wall
• RV OT
• RV apex

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Conclusions

• Inter-observer variability high
• ARVC/D absent gt present
• Task Force Suspected
• Certain signs ? probability ARVC/D reported
  present but inconsistent

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Conclusions

• No established imaging protocol
• Reduces IQ
• Optimal views?
• Motion other artifacts
• Different MRI equipment
• Lack cine for wall motion abnormalities