MRI accurately identifies early murine mammary cancers and reliably differentiates between in situ and invasive cancer: correlation of MRI with histology. (7th July 2015)

• Record Type: Journal Article
• Authors: Mustafi, Devkumar; Zamora, Marta; Fan, Xiaobing; Markiewicz, Erica; Mueller, Jeffrey; Conzen, Suzanne D.; Karczmar, Gregory S.
• Is Part Of: NMR in biomedicine. Volume 28:Number 9(2015:Sep.)
• Page Start: 1078
• Page End: 1086
• Publication Date: 2015-07-07
• Subjects: Nuclear magnetic resonance -- Periodicals; Magnetic Resonance Spectroscopy -- Periodicals; 574
• DOI: 10.1002/nbm.3348
• Languages: English
• ISSNs: 0952-3480

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>MRI methods that accurately identify various stages of mouse mammary cancer could provide new knowledge that may have a direct impact on the management of breast cancer in patients. This research investigates whether we can accurately follow the progression from <italic>in situ</italic> to invasive cancer by the evaluation of <italic>in vivo</italic> and <italic>ex vivo</italic> MRI, and in comparison with histology as the gold standard for the diagnosis and staging of cancer. Six C3(1)SV40Tag virgin female mice, aged 12–16 weeks, were studied. At this age, these mice develop <italic>in situ</italic> cancer that resembles human ductal carcinoma <italic>in situ</italic> (DCIS). Fast spin‐echo images of inguinal mammary glands were acquired at 9.4 T. After <italic>in vivo</italic> MRI, mice were sacrificed; inguinal mammary glands were excised and fixed in formalin for <italic>ex vivo</italic> MRI. Three‐dimensional, volume‐rendered, <italic>in vivo</italic> and <italic>ex vivo</italic> MR images were then correlated with histology. High‐resolution <italic>ex vivo</italic> scans facilitated the comparison of <italic>in vivo</italic> scans with histology. The sizes of mammary cancers classified as <italic>in situ</italic> on the basis of histology ranged from 150 to 400 µm in largest diameter, and the average signal intensity relative to muscle was 1.40 ± 0.18 on <italic>T</italic><sub>2</sub>‐weighted images. Cancers classified as invasive on the basis of histology were >400 µm in largest diameter, and the average intensity relative to muscle on <italic>T</italic><sub>2</sub>‐weighted images was 2.34 ± 0.26. Using a cut‐off of 400 µm in largest diameter to distinguish between <italic>in situ</italic> and invasive cancers, a <italic>T</italic><sub>2</sub>‐weighted signal intensity of at least 1.4 times that of muscle for <italic>in situ</italic> cancer, and at least 2.3 times that of muscle for invasive cancer, 96% of <italic>in situ</italic> and 100% of invasive cancers were correctly identified on <italic>in vivo</italic> MRI, using histology as the gold standard. Precise MRI–histology correlation demonstrates that MRI reliably detects early <italic>in situ</italic> cancer and differentiates <italic>in situ</italic> from invasive cancers in the SV40Tag mouse model of human breast cancer. Copyright © 2015 John Wiley & Sons, Ltd.</p> </abstract>