Abbreviated Breast MRI for Screening
Kuhl CK, Schrading S, et. al.
Introduction
- MRI associated with high direct and indirect costs
- conventional protocols time consuming to acquire and read
- limited access to screening MRI
Introduction
- Propose abbreviated MRI protocol
- early postcontrast period only
- MIP for fast overview of imaging volume
- Reduce time and cost associated with screening breast MRI
- Increase access
Methods - design
- Prospective, 2009 - 2010
- Hypothesized abbreviated protocol (AP) associated with reduced diagnostic accuracy
- May be worth it for increased speed/decreased cost
Methods - protocol
- T1 pre
- T1 post (1st acquisition)
- T1 subtracted
- MIP
- T1 post (2nd acquisition)
- T1 post (3rd acquisition)
- T1 post (4th acquisition)
- T1 post (5th acquisition)
- Coronal T1
- Axial T2
Methods - inclusion
- Women referred for screening MRI on clinical grounds
- 24% Dense breast tissue
- 26% Family history
- 50% Personal history (screening contralateral breast)
Methods - interpretation
- Two readers, 18 and 6 years experience
- Images read immediately
- 1st with AP
- MIPs read first, recorded presence of abnormal enhancement
- then rest of AP, given BI-RADS category
- then with FDP (full diagnostic protocol)
- 1st with AP
- Time to establish diagnosis recorded
Results - participants
- 443 women (163 underwent 2 annual screening rounds)
- 606 MRIs
- 82% of exams in women with mildly or moderately increased risk
- All were asymptomatic and had negative or benign mammogram at time of MRI
- 427 of 606 had negative or benign US
Results - cancer yield
- 11 cancers diagnosed (incidence = 2.5%)
- 4 DCIS
- 7 invasive
- All had (false) negative or benign mammograms
- 10 of 11 had (false) negative or benign US, 11th had negative targeted US at site of MRI detected cancer
- 8 high-risk lesions
- 3 papillomas
- 2 LCIS
- 2 ADH
- 1 radial scar
Results - timing
- Acquisition time
- AP: 3 m, 4 s
- FDP: 17 m, 4 s
- Reading time
- MIP: 2.8 s
- AP: 28 s
Results - diagnostic accuracy
p=0.317
Discussion
- Cancer yield and diagnostic accuracy equivalent between abbreviated and full protocols
- Substantially reduced time of acquisition and reading
- NPV of MIPs alone 99.8%
- Sens/spec of AP identical to FDP
Discussion
- FDP mainly needed for lesion characterization
- 38% of BI-RADS 3 lesions diagnosed on FAST images downgraded to BI-RADS 2 after reading full protocol
- Will decreased costs of AP justify increase in BI-RADS 3 diagnoses?
Discussion - limitations
- High volume MRI readers, perhaps not transferrable to community practice
Editorial - Elizabeth Morris
- MRI superior to mammography and US
- Likelihood of finding cancer at biopsy < 10% if performed on basis of US findings, 30% if on basis of MRI findings
- MRI geared to detect more biologically relevant cancers (neovascularity, inflammation)
Editorial
- Currently, MRI limited to high risk populations
- Limited access
- expensive
- time-consuming
Editorial
- FAST MRI could reduce barriers to MRI screening
- MRI screening should be offered to all eligible patients
- MRI should be next additional screening modality, not US
Abbreviated Breast MRI for Screening Kuhl CK, Schrading S, et. al.
Abbreviated Breast MRI for Screening
By Jason Hostetter
Abbreviated Breast MRI for Screening
- 313
