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Pitfalls in breast MRI : How to deal between
Sensitivity and Specifcity ?
P. Taourel, E. Pages
Breast MRI : a weak specificity • Studies comparing MRI and MG
– Staging of brast cancer : Spe = 70% close to Spe of MG
– High risk women : Spe = 90 % • Why this feeling of low specificity
– enhancement ≠ cancer – Lack of experience – Difficulty of biopsy
C Kuhl Radiology 2007
Breast MRI : is it perfectly sensitive ? • The sensitivity of an exam depends of the gold standard > 95 % in most of the studies ≈ 75 % in screening studies = 85 % in the stidy with gold standard = pathologic analysis of mastectomy • MRI Sensitivity > Sensitivity of other imaging modalities
Causes of avoidable F+
• Artefacts • Normal structures • Benign tumors
Causes of avoidable F+
• Artefacts • Normal structures • Benign tumors
Backround enhancement
• Bilateral and symmetric
• Hormonal and therapeutic context
• Age of the patient • The backround
enhancement must be graded
Genetic risks, BRCA 1
40 years old
Genetic risks
40 years old
Right mass : fibroadenoma
ovariectomy
To analyze / classification BIRADS
• Mass – 3D – Cancer, FA, papilloma, fat necrosis, sclerosing
adenosis, lymph node, some atypical form of benign lesions
– Key features for Benign: • Smooth outline • Regular form • Homogeneous enhancement (value if big) • Hyper T2 • Fat content • Weak enhancement and no wash-out
2009 2010
Value of hyper T2 if homogeneous
Rim must be analyzed according to the content and the regular pattern
To analyze / BIRADS classification
• Non mass enhancement – Neither mass nor focus – Benign mass, young patient, inflammation,
DCIS, ILC – Key features for enhancement :
• Bilateral and symmetric • Cysts ++ • Negative findings
To analyze / classification BIRADS
• Focus – < 5 mm – Very low rate of malignancy – Key features for benign (no F.U = BIRADS 2)
• Multiple • No wash-out • Clinical context
F -
• Lack of enhancement • Not seen
– Backround enhancement, artefact – small – Tricky area
• Misinterpretation • Mismanagement
Causes of False negative
• Retrospective review of 60 pairs of breast cancer
• 47% of « errors » – 10% = misdiagnosis – 25% = misinterpretation – 12% = mismanagement
Pages Radiology 2012
Lack of enhancement
• DCIS • Small invasive cancer • Some pathologic pattern:
– Inflammatory cancer – Invasive lobular carcinoma
F -
• Lack of enhancement • Not seen
– Backround enhancement, artefact – small – Tricky area
• Misinterpretation • Mismanagement
Oct 2004 Mai 2005
1an plus tard
F -
• Lack of enhancement • Not seen
– Backround enhancement, artefact – small – Tricky area
• Misinterpretation • Mismanagement
2007
2008
Benign morphology’’ : oval form, smooth outlines, non enhanced septas
Forme ronde Phénotype triple-négatif
RE-
RP-
HER2 -
Benign/malignant association
1 year later
2003
2005
2006
Be careful with kinetic, particularly in menopausal patients
Temps (min)
1
2
3
2
Plateau
Lavage
Progressive
ROI > 3 pixels Région la plus suspecte
OR not to have malignant curve in menopausal patients : 2.94 : initial rise 2.38 : washout I Millet Radiology dec 2013 -
F -
• Lack of enhancement • Not seen
– Backround enhancement, artefact – small – Tricky area
• Misinterpretation • Mismanagement
• Retrocystic enhancement
Importance du clip
How to avoid F+ and F- ?
1. To recognize the pseudo-enhancement 2. To negative normal structure : bilateral foci,
punctuate enhancement, lymph nodes 3. 6 month FU 4. Interpretation according to clinical context and
personal status - focus/BIRADS - enhancement/menopausal status
5. Be careful with stability (morphology +++) 6. Be careful with autosatisfaction : FU of benign
results in biopsy performed on 2d look US
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