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Correlation of In Vivo and Ex Vivo ADC and T2 of In Situ and Invasive Murine Mammary Cancers.

Fan X, Macleod K, Mustafi D, Conzen SD, Markiewicz E, Zamora M, Vosicky J, Mueller J, Karczmar GS - PLoS ONE (2015)

Bottom Line: Regions of interest were manually traced on T2W images defining features that could be identified on in vivo and ex vivo images.Although motion, fixation, and temperature differences affect ADC and T2, these results show a reliable relationship between ADC and T2 in vivo and ex vivo.As a result ex vivo images can provide valuable information with clinical and research applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, The University of Chicago, 5841 S. Maryland Avenue, Chicago, IL, 60637, United States of America.

ABSTRACT
Ex vivo MRI may aid in the evaluation of surgical specimens, and provide valuable information regarding the micro-anatomy of mammary/breast cancer. The use of ex vivo MRI to study mouse mammary cancer would be enhanced if there is a strong correlation between parameters derived from in vivo and ex vivo scans. Here, we report the correlation between apparent diffusion coefficient (ADC) and T2 values measured in vivo and ex vivo in mouse mammary glands with in situ cancers (mammary intraepithelial neoplasia (MIN)) and invasive cancers (those which spread outside the ducts into surrounding tissue). MRI experiments were performed on the Polyoma middle T oncoprotein breast cancer mouse model (n = 15) in a 9.4T scanner. For in vivo experiments, T2-weighted (T2W) images were acquired to identify abnormal regions, then ADC and T2 values were measured for nine selected slices. For ex vivo experiments, a midline incision was made along the spine, and then skin, glands, and tumors were gently peeled from the body. Tissue was fixed in formalin, placed around a mouse-sized sponge, and sutured together mimicking the geometry of the gland when attached to the mouse. The same pulse sequences used for in vivo experiments were repeated for ex vivo scans at room temperature. Regions of interest were manually traced on T2W images defining features that could be identified on in vivo and ex vivo images. The results demonstrate a strong positive correlations between in vivo and ex vivo invasive cancers for ADC (r = 0.89, p <0.0001) and T2 (r = 0.89, p <0.0001) values; and weak to moderate positive correlations between in vivo and ex vivo in situ cancers for ADC (r = 0.61, p <0.0001) and T2 (r = 0.79, p <0.0001) values. The average ex vivo ADC value was about 54% of the in vivo value; and the average ex vivo T2 was similar to the in vivo value for cancers. Although motion, fixation, and temperature differences affect ADC and T2, these results show a reliable relationship between ADC and T2 in vivo and ex vivo. As a result ex vivo images can provide valuable information with clinical and research applications.

No MeSH data available.


Related in: MedlinePlus

T2W in vivo image (left panel) matched with the corresponding ex vivo image (right panel) showing a mouse mammary gland from head to tail (top to bottom)–near the neck, heart, liver, below the kidney, and near the legs, respectively.Matching features (all invasive cancers) in the in vivo and ex vivo images, identified by visual inspection, were circled with the same color. The displayed image FOV is 25.6 × 25.6 mm.
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pone.0129212.g002: T2W in vivo image (left panel) matched with the corresponding ex vivo image (right panel) showing a mouse mammary gland from head to tail (top to bottom)–near the neck, heart, liver, below the kidney, and near the legs, respectively.Matching features (all invasive cancers) in the in vivo and ex vivo images, identified by visual inspection, were circled with the same color. The displayed image FOV is 25.6 × 25.6 mm.

Mentions: Immediately after the in vivo MRI experiments, the mouse skin and glands were carefully removed from the body. Fig 1 shows an example of the excised skin after fixation and ready for ex vivo imaging. During the fixing process, the skin shrinks or stretches slightly compared to in vivo skin. The mouse skin was then sutured together around a mouse-sized sponge for ex vivo MRI. Fig 2 compares in vivo (left panel) and ex vivo (right panel) T2W images from a single mouse, three slices from the top glands and two slices from bottom glands. Gross features, all invasive cancers, indicated by circles of the same color, are well matched, despite the change in ex vivo lesion shape and size. Because the features selected for analysis are sparse, the corresponding features on in vivo and ex vivo images can be identified unambiguously.


Correlation of In Vivo and Ex Vivo ADC and T2 of In Situ and Invasive Murine Mammary Cancers.

Fan X, Macleod K, Mustafi D, Conzen SD, Markiewicz E, Zamora M, Vosicky J, Mueller J, Karczmar GS - PLoS ONE (2015)

T2W in vivo image (left panel) matched with the corresponding ex vivo image (right panel) showing a mouse mammary gland from head to tail (top to bottom)–near the neck, heart, liver, below the kidney, and near the legs, respectively.Matching features (all invasive cancers) in the in vivo and ex vivo images, identified by visual inspection, were circled with the same color. The displayed image FOV is 25.6 × 25.6 mm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4514815&req=5

pone.0129212.g002: T2W in vivo image (left panel) matched with the corresponding ex vivo image (right panel) showing a mouse mammary gland from head to tail (top to bottom)–near the neck, heart, liver, below the kidney, and near the legs, respectively.Matching features (all invasive cancers) in the in vivo and ex vivo images, identified by visual inspection, were circled with the same color. The displayed image FOV is 25.6 × 25.6 mm.
Mentions: Immediately after the in vivo MRI experiments, the mouse skin and glands were carefully removed from the body. Fig 1 shows an example of the excised skin after fixation and ready for ex vivo imaging. During the fixing process, the skin shrinks or stretches slightly compared to in vivo skin. The mouse skin was then sutured together around a mouse-sized sponge for ex vivo MRI. Fig 2 compares in vivo (left panel) and ex vivo (right panel) T2W images from a single mouse, three slices from the top glands and two slices from bottom glands. Gross features, all invasive cancers, indicated by circles of the same color, are well matched, despite the change in ex vivo lesion shape and size. Because the features selected for analysis are sparse, the corresponding features on in vivo and ex vivo images can be identified unambiguously.

Bottom Line: Regions of interest were manually traced on T2W images defining features that could be identified on in vivo and ex vivo images.Although motion, fixation, and temperature differences affect ADC and T2, these results show a reliable relationship between ADC and T2 in vivo and ex vivo.As a result ex vivo images can provide valuable information with clinical and research applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, The University of Chicago, 5841 S. Maryland Avenue, Chicago, IL, 60637, United States of America.

ABSTRACT
Ex vivo MRI may aid in the evaluation of surgical specimens, and provide valuable information regarding the micro-anatomy of mammary/breast cancer. The use of ex vivo MRI to study mouse mammary cancer would be enhanced if there is a strong correlation between parameters derived from in vivo and ex vivo scans. Here, we report the correlation between apparent diffusion coefficient (ADC) and T2 values measured in vivo and ex vivo in mouse mammary glands with in situ cancers (mammary intraepithelial neoplasia (MIN)) and invasive cancers (those which spread outside the ducts into surrounding tissue). MRI experiments were performed on the Polyoma middle T oncoprotein breast cancer mouse model (n = 15) in a 9.4T scanner. For in vivo experiments, T2-weighted (T2W) images were acquired to identify abnormal regions, then ADC and T2 values were measured for nine selected slices. For ex vivo experiments, a midline incision was made along the spine, and then skin, glands, and tumors were gently peeled from the body. Tissue was fixed in formalin, placed around a mouse-sized sponge, and sutured together mimicking the geometry of the gland when attached to the mouse. The same pulse sequences used for in vivo experiments were repeated for ex vivo scans at room temperature. Regions of interest were manually traced on T2W images defining features that could be identified on in vivo and ex vivo images. The results demonstrate a strong positive correlations between in vivo and ex vivo invasive cancers for ADC (r = 0.89, p <0.0001) and T2 (r = 0.89, p <0.0001) values; and weak to moderate positive correlations between in vivo and ex vivo in situ cancers for ADC (r = 0.61, p <0.0001) and T2 (r = 0.79, p <0.0001) values. The average ex vivo ADC value was about 54% of the in vivo value; and the average ex vivo T2 was similar to the in vivo value for cancers. Although motion, fixation, and temperature differences affect ADC and T2, these results show a reliable relationship between ADC and T2 in vivo and ex vivo. As a result ex vivo images can provide valuable information with clinical and research applications.

No MeSH data available.


Related in: MedlinePlus