Application Of T1 Mapping And T2 Mapping Sequence In Diagnosis Of Breast Cancer

Objective: The value of T1 and T2 values in the diagnosis of breast cancer was discussed by T1 mapping and T2 mapping sequence.Methods: Forty-six patients with breast tumors underwent conventional breast plain scan and dynamic contrast-enhanced magnetic resonance examination.T1 mapping and T2 mapping sequences were added before enhancement,and T1 mapping sequences were added 5 minutes after enhancement.In the study related to T1 mapping sequence,3 patients were excluded without meeting the requirements,and 7 patients were excluded from the study related to T2 mapping sequence.Finally,43 patients and 39 patients were included.Tumor size,ADC value,T1 value before enhancement(T1pre),T2 value,and T1 value after enhancement(T1post)were measured.The difference of T1 value before and after enhancement(ΔT1= T1pre-T1post)and the change rate of T1 value before and after enhancement(Δ T1%= Δ T1 /T1 pre ×100%)were calculated.T1 pre,T2 value and T1 post of the contralateral normal breast glands were measured,and Δ T1 and Δ T1% of the normal glands were calculated.The independent sample t test or Mann-Whitney u test was used to analyze whether the differences of T1 pre,T1post,ΔT1,ΔT1% and T2 value among the groups were statistically significant.The ROC curve was drawn for the groups with statistically significant differences,and Youden index was calculated to obtain the optimal threshold for differential diagnosis.Spearman correlation analysis was used to evaluate the correlation between T1 pre,T1post,ΔT1,ΔT1%,T2 value and tumor size,ADC value and expression level of Ki-67 in breast cancer group.Results: 1.The T1 post of benign tumor was lower than that of normal gland,and ΔT1 and ΔT1% were higher than that of normal gland,and the differences were statistically significant(P<0.05).The AUC of T1 post,Δ T1 and Δ T1% for differentiating normal gland from benign tumor were 0.164(95% : 0.000-0.381),0.841(95% : 0.690-0.992)and 0.877(95% : 0.710-1.000);When ΔT1=1025.57 ms,the sensitivity and specificity of differentiating normal glands from benign tumors were 80%and 81.8%,respectively.When ΔT1%=59.22%,the sensitivity and specificity of differentiating normal glands from benign tumors were 80% and 95.5%.The difference of T1 pre between normal glands and benign tumors was not statistically significant.2.The T1 post of breast cancer was lower than that of normal glands,and ΔT1 andΔT1% were higher than that of normal glands,and the differences were statistically significant(P<0.05),and the AUC of T1 post,ΔT1 and ΔT1% for differentiating normal glands from breast cancer were 0.040(95% : 0.000-0.081),0.874(95% : 0.792-0.957)and 0.950(95% : 0.890-1.000),respectively.When ΔT1=685.115 ms,the sensitivity and specificity of differentiating normal glands from breast cancer were 100%and 72.7%.When ΔT1%=53.78%,the sensitivity and specificity of differentiating normal glands from breast cancer were 97.4% and 93.2%.The difference of T1 pre between normal glands and breast cancer was not statistically significant.3.There were no significant differences in T1 pre,T1post,ΔT1,ΔT1% between benign tumor and breast cancer,partial invasive cancer and invasive cancer,ER+ breast cancer and ER-breast cancer,PR+ breast cancer and PR-breast cancer,HER-2 + breast cancer and HER-2-breast cancer,axillary lymph node metastatic breast cancer and axillary lymph node non-metastatic breast cancer.4.There was no correlation between T1 pre,T1post,ΔT1,ΔT1% and tumor size,ADC value and expression level of Ki-67.5.The T2 value of breast cancer was greater than that of normal glands,the difference was statistically significant(P<0.05),and the AUC of T2 value for differentiating normal glands from breast cancer was 0.775.When T2 value =91.225 ms,the specificity and sensitivity for differentiating normal glands from breast cancer were 77.8% and77.1%.6.There was no statistically significant difference in T2 value between normal glands and benign tumors,benign tumors and breast cancer,some invasive cancers and invasive cancers,ER+ breast cancer and ER-breast cancer,PR+ breast cancer and PRbreast cancer,HER-2 + breast cancer and HER-2-breast cancer,axillary lymph node metastatic breast cancer and axillary lymph node non-metastatic breast cancer.7.There was a moderate negative correlation between T2 value and tumor size and ADC value in breast cancer(P<0.05,r=-0.351、P<0.05,r=-0.348).There was no correlation between T2 value and expression level of Ki-67 in invasive breast cancer.Conclusion:1.The quantitative determination of T1 and T2 values by T1 mapping and T2 mapping sequence can be used to distinguish normal glands and benign tumors,normal glands from breast cancer,among all the indicators related to T1 value,ΔT1%in the two groups of differential diagnosis has the best efficacy.2.The T2 value of breast cancer is correlated with tumor size and ADC value,which may be used as a quantifiable imaging index to reflect the prognosis of breast cancer.