Keywords:
Contrast agent-intravenous, MR, Pelvis, Genital / Reproductive system female, Cancer
Authors:
T. Fukunaga, S. Fujii, C. Inoue, S. Kaneda, T. Kaminou, T. Ogawa; Yonago/JP
DOI:
10.1594/ecr2013/C-1735
Results
Study population
In 86 endometrial lesions,
68 were type I endometrial carcinomas (well differentiated: grade 1 (n=52); moderately differentiated: grade 2 (n=16)) and 18 were type II endometrial carcinomas (poorly differentiated: grade 3 (n=10); papillary serous adenocarcinoma (n=4) ; clear-cell adenocarcinoma (n=4)).
Clinical and pathologic characteristics of the 86 patients in the study population are presented in Table 1.
Semi-quantitative analysis
Interclass correlation coefficients (ICCs) were 0.93(SImax) / 0.95(SI0) / 0.93(SI(piriformis)) .
All the ROI measurements indicated excellent correlation.
There was no significant difference in the all enhancement parameters except for SImax between 1.5-T and 3-T MR (P>0.5).
Each enhancement parameters for type II carcinomas were higher than for type I carcinomas (Table 2).
There was a significant difference in SIrel (P< 0.0001),
WIR (P<0.0001) and SImax/SI (piriformis) ratios (P<0.0001) between the two groups.
Whereas no significant difference in SImax was noted between the two groups (P> 0.05).
Threshold criteria for type II tumor
Further analysis was carried out to establish optimal threshold criteria for the prediction of type II carcinomas using the parameters with significant differences between two groups. There was some overlap in the enhancement characteristics between two groups using the semi-quantitative parameters (Fig.
2a–c). ROC analysis indicated that a cut-off WIR ≥ 43.7 as predictive of type II carcinomas produced optimal diagnostic performance providing a sensitivity of 78%,
specificity of 75%,
accuracy of 75%, positive predictive value (PPV) of 45% and negative predictive value (NPV) of 93% (Fig.3). In corporating piriformis muscle enhancement as an internal reference,
and therefore probably a more valuable measure when applied across different MR systems and manufacturers,
regarding SImax/SI(piriformis) ratio,
a threshold value ≧ 1.54 divided the two groups was giving 67% for sensitivity,
81% for specificity,
77% for accuracy,
48% for PPV,
90% for NPV.
Using relative enhancement data,
a cutoff value of SIrel 59% produced a sensitivity of 94%,
specificity of 60%,
PPV of 39%,
NPV of 95% and an accuracy of 67%.