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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

Plots of in vivo versus ex vivo average T2 values over ROIs from 11 mice.(a) lymph nodes, (b) in situ cancers, and (c) invasive cancers. The gray line is the linear fit through the points. The linear relationship between in vivo and ex vivo T2s, the correlation coefficient (r) and p value are given on the plot.
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pone.0129212.g006: Plots of in vivo versus ex vivo average T2 values over ROIs from 11 mice.(a) lymph nodes, (b) in situ cancers, and (c) invasive cancers. The gray line is the linear fit through the points. The linear relationship between in vivo and ex vivo T2s, the correlation coefficient (r) and p value are given on the plot.

Mentions: T2 values were calculated in mammary gland ROIs from 11 of the mice (131 different ROIs, 4 mice died before measurements could be completed, Table 1). Fig 6 shows the plots of in vivo vs. ex vivo T2 values, averaged over ROIs from lymph nodes, in situ cancers, and invasive cancers. There is a strong positive correlation (r = 0.89, p < 0.0001) between in vivo and ex vivo T2s for invasive cancers, and a moderate but statistically significant positive correlation (r = 0.79, p < 0.0001) between in vivo and ex vivo T2s for in situ cancers. There is no correlation (r = 0.37, p = 0.11) between in vivo and ex vivo T2s for lymph nodes. Paired t-test showed that the in vivo T2 values were significantly higher (p < 0.001) than ex vivo values for in situ cancers, but significantly lower for lymph nodes (p < 0.001). The average in vivo T2 for invasive cancers was about the same as ex vivo T2 (p > 0.05) (Table 3). One-way ANOVA and Tukey's HSD showed that the in vivo T2 values for lymph nodes were significantly lower (p < 0.001) than in vivo T2 values for in situ cancers and invasive cancers. However, ex vivo T2 values were not significantly different between lymph nodes, in situ cancers, and invasive cancers.


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)

Plots of in vivo versus ex vivo average T2 values over ROIs from 11 mice.(a) lymph nodes, (b) in situ cancers, and (c) invasive cancers. The gray line is the linear fit through the points. The linear relationship between in vivo and ex vivo T2s, the correlation coefficient (r) and p value are given on the plot.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0129212.g006: Plots of in vivo versus ex vivo average T2 values over ROIs from 11 mice.(a) lymph nodes, (b) in situ cancers, and (c) invasive cancers. The gray line is the linear fit through the points. The linear relationship between in vivo and ex vivo T2s, the correlation coefficient (r) and p value are given on the plot.
Mentions: T2 values were calculated in mammary gland ROIs from 11 of the mice (131 different ROIs, 4 mice died before measurements could be completed, Table 1). Fig 6 shows the plots of in vivo vs. ex vivo T2 values, averaged over ROIs from lymph nodes, in situ cancers, and invasive cancers. There is a strong positive correlation (r = 0.89, p < 0.0001) between in vivo and ex vivo T2s for invasive cancers, and a moderate but statistically significant positive correlation (r = 0.79, p < 0.0001) between in vivo and ex vivo T2s for in situ cancers. There is no correlation (r = 0.37, p = 0.11) between in vivo and ex vivo T2s for lymph nodes. Paired t-test showed that the in vivo T2 values were significantly higher (p < 0.001) than ex vivo values for in situ cancers, but significantly lower for lymph nodes (p < 0.001). The average in vivo T2 for invasive cancers was about the same as ex vivo T2 (p > 0.05) (Table 3). One-way ANOVA and Tukey's HSD showed that the in vivo T2 values for lymph nodes were significantly lower (p < 0.001) than in vivo T2 values for in situ cancers and invasive cancers. However, ex vivo T2 values were not significantly different between lymph nodes, in situ cancers, and invasive cancers.

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