Diffusion Magnetic Resonance Imaging in Differentiation of Ovarian Cystic Lesions

Background: MRI can specifically diagnose some certain pathologic types by providing accurate information on fat, collagen and hemorrhage. Diffusion-weighted magnetic resonance imaging, an emerging non-invasive MRI technique, is of the capability to evaluate the extent of microscopic diffusion which might exist in biologic tissues. Evidence has shown that DWI-MRI and ADC were beneficial in differentiating malignant from benign ovarian lesions and may be helpful to predict suboptimal cytoreduction in ovarian cancer. The aim of this study to assess the role of magnetic resonance imaging with diffusion weighted images in the assessment and differentiation of ovarian cystic lesions.

Methods: This prospective study was conducted on 30 female patients who are proved by ultrasound to have ovarian cystic lesions. Selected patients were given butylscopolamine bromide (20mg) administered IV or intramuscularly at the beginning of the examination. Imaging is performed with the patient in the supine position with an empty urinary bladder. A distended urinary bladder is not recommended because it increases phase ghost artifacts and can compress the uterus.

Results: As regards diagnosis according to Ultrasound examination, revealed that ovarian cancer and simple cyst were the most frequent (26.7% and 20% respectively), followed by Tubo-ovarian hydrosalpinx and Hemorrhagic cyst (10%) each. Ovarian serous cyst adenoma constituted (6.7%), while pyosalpinx, PCO, hydrosalpinx, and endometrial cyst constitutes (3.3%) each.

As regards diagnosis according to MRI examination, Simple cyst and ovarian cancer were the most frequent (13.3%) each, followed by Tubo-ovarian hydrosalpinx and Hemorrhagic cyst (10%) each. Krekenberg tumor, Ovarian dermoid, and Ovarian serous cyst adenoma constituted 6.7% each. As regards the ADC value was significantly lower in the malignant lesions (0.7*103) than benign ones (0.9*103). As regards histopathologic confirmation, 23 cases of the studied women, Ovarian cancer (17.4%), Tubo-ovarian hydrosalpinx (13.0%), and Hemorrhagic cyst (13.0%) were the most common diagnosis. Ovarian dermoid, Krekenberg tumor, and Ovarian serous cyst adenoma constituted 8.7% each. Other less frequent diagnosis included Endometeriotic cyst, Hydrosalpnix, Mucinous cystadenoma, Ovarian serous cyst adenocarcinoma, Ovarian dysgerminoma and Terato-dermoid (4.3%) each. The mean ADC value was significantly lower in the malignant lesions than benign ones. At a cut off ≤0.7, ADC showed a significant good diagnostic value of malignant lesions with sensitivity, Specificity, and an accuracy.

Conclusions: DWI to conventional MRI is an important tool. It improves the specificity of MRI and thus increasing radiologist’s confidence in image interpretation which will finally reflect on patients’outcome and prognosis. Cost effective technique (no additional cost to MRI examination), was easily added to MR study protocols.