Effectiveness of Semi-Quantitative Multiphase Dynamic Contrast-Enhanced MRI at 3 Tesla as a Predictor of Malignancy in Adnexal Masses
M. Effectiveness of Semi-Quantitative Multiphase Dynamic Contrast-Enhanced MRI at 3 Tesla as a Predictor of Malignancy in Adnexal Masses,
Iran J Radiol.
Online ahead of Print
; 11(30th Iranian Congress of Radiology):e21333.
Ovarian cancer is the second commonest gynecological malignancy, the fifth commonest cancer affecting women in the developed world, and the leading indication for gynecologicaloncological surgery. There is a wide range of management options for ovarian cancers from conservative to radical surgery; conservative laparoscopic surgery in young women wishing to preserve their childbearing potential (borderline epithelial tumors) is the preferred method. The current investigation tool for management of ovarian masses consist of a TVS as the screening tool and determining the RMI using US score, menopausal state and CA 125 levels. MRI with Gd is the next preferred method, while it keeps indeterminate masses which are managed intra-operatively using macroscopic and histological frozen section analysis of vegetations or solid tumor components. Several studies have emphasized the diagnostic performance of new imaging modalities such as dynamic contrast enhanced MRI (DCE-MRI) as well as their DWI and MRS findings in the determination of adnexal masses.
The aim of this study was to determine diagnostic accuracy of semi-quantitative factors resulted from dynamic curves of enhancement of adnexal masses at 3 tesla MRI and to determine threshold criteria of malignancy or benignity using them.
Patients and Methods:
Forty-nine adnexal masses in 40 patients hospitalized in onco-gynecologic ward of Valiasr hospital with surgical plan from 2011 to 2012, were investigated with multiphasic dynamic contrast enhanced MRI using 3 tesla MRI. After choosing ROI, semi-quantitative factors of enhancement were drawn from the enhancement curve through home-made MATLAB software. Using histological result of resected adnexal mass as the gold standard, masses were categorized into benign versus malignant group. Myometrium and psoas muscle enhancement patterns were also analyzed as the internal reference.
The maximum actual enhancement (SI max), maximum relative enhancement (SI rel) and Wash out rate (WOR) did not show any significant difference in the two groups while the amount of Wash in rate (WIR), Area under curve in 60 s (AUC60), SI peak tumor, SI tumor in 30 s also SI max (tumor)/SI max (psoas), WIR (tumor)/WIR (psoas), SI max (tumor)/SI max (myometrium) and WIR (tumor)/WIR (myometrium) ratios were significantly higher in malignant group in comparison with benign ones (P value less than 0.05). Using area under the ROC curve (AUROC) malignancy and benignity threshold were determined for each of semi-quantitative factors; WIR value of more than 2.45 could be indicative of a malignant adnexal mass (specificity and PPV of 100%) while WIR value of less than 0.38 could be predictive of a benign one (sensitivity and NPV of 100%). Similar to WIR, the SI max (tumor)/SI max (psoas) more than 3.25, SI max (tumor)/SI max (myometrium) more than 2.8 and WIR (tumor)/ WIR (psoas) more than 22.5 were more accompanied by malignant adnexal masses while SI max (tumor)/ SI max (psoas) less than 0.99, SI max (tumor)/ SI max (myometrium) less than 0.61 and WIR (tumor)/ WIR (psoas) less than 0.91 were more suggestive of a benign adnexal mass.
This study showed that DCE sequences are more effective than simple CE sequences for qualitative assessment of enhancement, and based on this evidence, we assume DCE-MRI should be incorporated into our institutions standard practice to be used routinely during qualitative evaluation of images.
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