How to measure breast cancer tumoral size at MR imaging?
OBJECTIVE
To compare the accuracy of different MR sequences to measure tumor size.


METHODS
Eighty-six women (mean age: 53 years (30-78)) who underwent preoperative MRI for breast cancer were included. Maximal diameters of the index tumor (IT) and of the whole extent of the tumor (WET) were measured on T2-weighted (T2W) sequences, on dynamic contrast-enhanced (DCE) T1-weighted (T1W) sequences and on Maximal Intensity Projection (MIP) reconstructions. Agreements with pathological size were evaluated using concordance correlation coefficient (k).


RESULTS
Median pathological size of IT was 20mm (13-25 mm, interquartile range). Median pathological size of the WET was 29 mm (16-50mm, interquartile range). Measurement of IT showed a good concordance with pathological size, with best results using T2W (k = 0.690) compared to MIP (k = 0.667), early-subtracted DCE frame (k = 0.630) and early-native DCE frame (k = 0.588). IT was visible on T2W in 83.7% and accurately measured within 5mm in 69.9%. Measurement of WET was superior using early-subtracted DCE frame (k = 0.642) compared to late-native frame (k = 0.635), early-native frame (k = 0.631), late-subtracted frame (k = 0.620) and MIP (k = 0.565). However, even using early-subtracted frame, WET was accurately measured within 5mm only 39.3%.


CONCLUSIONS
If visible, IT size is best measured on T2W with a good accuracy (69%) whereas WET is best estimated on early-subtracted DCE frame. However, when adjacent additional sites exist around IT, suspected surrounding disease components need to be proved by pathological analysis.
Department of Radiology, Hôpital Tenon, Assistance Publique Hôpitaux de Paris, Institut Universitaire de Cancérologie (IUC) Pierre et Marie Curie, Cancer Est, Paris, France. Electronic address: isabelle.thomassin@tnn.aphp.fr.
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I
Thomassin-Naggara
Pascale
P
Siles
I
I
Trop
J
J
Chopier
E
E
Darai
M
M
Bazot
S
S
Uzan
D000328:Adult; D000368:Aged; D000465:Algorithms; D001943:Breast Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique; D047368:Tumor Burden
Breast carcinoma; MRI; Size