الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Ovarian cancer has been a leading malignancy endangering women’s health with high rate of worldwide prevalence. It is well known as the silent killer as it is mostly presented late with vague nonspecific symptoms. Optimum management depends upon accurate preoperative characterization and staging of the ovarian mass. Imaging modalities have advanced greatly in order to improve the characterization of female pelvic masses.
More recently functional methods as MR dynamic contrast enhanced imaging and MR diffusion have been tested to improve the diagnostic confidence by increasing sensitivity, specificity and accuracy of MRI.
The aim of our study was to demonstrate the role of MRI diffusion and dynamic contrast enhanced MRI in preoperative characterization of ovarian tumors.
This study was a prospective study. The study population comprised 50 consecutive women who were suspected to have ovarian neoplastic mass. Patients were collected between January 2018 and December 2018. Age ranged from 12 to 70 years with mean +/_ SD of the age (39 +/_ 15.9)., They underwent MRI imaging after meeting the inclusion criteria that based on the clinical history and gray scale transabdominal and or tran-vaginal sonography findings. All patients signed a written informed consent before MRI examination.
All patients included in this study had previous trans-abdominal or trans-vaginal real time ultrasonography with diagnosis of (complex ovarian lesions, cystic lesion with solid vegetation or thick septa or soft tissue component, solid ovarian lesions or suspicious adnexal lesions).Patients with simple cystic ovarian lesions, ovarian lesions with pure fatty component, impaired renal functions or general contraindications to MRI as the presence of any paramagnetic substances such as pacemakers, metallic clips or claustrophobic patients were excluded from the study.
Diffusion weighted imaging was acquired in the axial plane prior to administration of contrast medium by using a single shot echo-planar imaging sequence with b values (0, 800, 1000).
MRI dynamic contrast enhanced sequence is recently referred as Permeability MRI as it shows that factors related to tumor biological processes and neoangiogenesis are determinants in the contrast uptake dynamics in ovarian tumors. In this study, we performed rapid DCE imaging using GRE T1WI FAT SAT with temporal resolution of 14 sec for each phase. We performed 30 consecutive phases, each phase was 14 seconds with the whole sequence lasting for 7 minutes. The imaged stack should include part of the soft tissue inside the ovarian mass (i.e., solid portion, papillary projection, or thickened irregular septa) and the adjacent external myometrium in the optimal plane.
All patients underwent operative management. The results of MRI were correlated with the histopathological findings. Three patients were excluded from the study after proved to be non-tumorous conditions. The results of the remaining 47 cases were analyzed.
Among our patients 37/47 cases (78.7%) showed diffusion restriction and 10/47 cases (21.3%) showed facilitated diffusion. The cut off value of ADC value below which malignancy is expected is less than 1x10-3 mm2/sec. There was statistical significance between ADC value and pathological diagnosis.
Regarding semi-quantitative analysis in dynamic contrast enhanced MRI, measurements were evaluated and correlated to the final histopathological results. There was statistical significance between SI max, WIR & WOR and pathological diagnosis with higher sensitivity specificity and accuracy in relation to WOR. There was no statistical significant difference between MRE% and pathological diagnosis.
Regarding the time signal intensity curves; we found that type 1 Curve was 100% specific for benign tumors while type 2 and 3 curves carry malignant probability with accuracy 95%, sensitivity 88% and specificity 92%. NPV 100%
ROC curve analysis was used for prediction of malignancy depending on conventional based diagnosis, DWI based diagnosis, dynamic contrast enhancement-based diagnosis and combined conventional MRI with DWI and dynamic contrast enhancement-based diagnosis.
There was statistical significant difference between the three methods of diagnosis and the pathological diagnosis. However; the AUC, sensitivity, specificity and accuracy were higher on DWI and dynamic contrast enhancement- based diagnosis than those on conventional based diagnosis.
Conclusion
In conclusion, addition of DWI and DCE MR sequences to conventional MRI has markedly improved the diagnostic accuracy. DCE MRI provides additional information for tumor vascularity.