Susceptibility-Weighted MRI in the Evaluation of Gynecologic DiseasesSusceptibility-Weighted MRI in the Evaluation of Gynecologic Diseases

Introduction: Owing to the advanced development of MRI science, it causes obvious great changes of many diseases that affect the female genital system and affect their fertility. Hemorrhagic gynecological diseases especially endometriosis affect young females and cause cyclic pain, in addition to infertility. So early detection is essential for proper treatment. Susceptibility-weighted (SWI) as one of the most recent newly created MRI sequences is highly sensitive to detect products of hemorrhage within different gynecologic disorders with 94.7% sensitivity being more meticulous than conventional MRI sequences as T1 and T2. Aim of the Work: A comparison between T1 and T2 as conventional MRI sequences with susceptibility-weighted images (SWI) in many gynecologic disorders by the detection of the presence of internal products of hemorrhage at any stage. Subjects and Methods: 48 consecutive patients from Benha University clinics (age range, 17 60 years; mean age, 35.67 years). The patients included in the study were presenting with pelvic pain, irregular menses, Dyspareunia, and swelling. All with suspicious diagnosis of ovarian and extra-ovarian lesions. 38 patients out of the 48 patients were known to contain hemorrhagic disorder; all the patients underwent MRI routine pelvis protocol adding SWI sequence. Results: There was a greatly significant difference between SWI and conventional MRI sequences T1and T2 with sensitivity 94.7%, 57.9% and 33.3% respectively. Conclusion: SWI is a promising tool in the evaluation of hemorrhagic foci within different gynecological disorders. The great ability of detecting hemosiderin foci increases the value of SWI over conventional MRI or US.


Introduction
Hemorrhagic gynecological diseases especially endometriosis is of most common causes of infertility that affect young females manifesting primarily as a cyclic pain as well as dysmenorrhea, so its early diagnosis sometimes becomes a challenge and is essential for proper treatment.
MRI can differentiate fine details about the composition of soft-tissue masses using differences in MR relaxation criteria seen in various types of tissue. This detail is precious in determining the characters of soft-tissue masses [1].
One of the newly created MRI functional sequences is SWI that is greatly able to detect compounds that distort the local magnetic field producing signal void.
This property enables SWI to detect hemosiderin, deoxyhemoglobin, calcium, etc. So, it is the sequence that can detect even minimal hemorrhagic foci. Due to the successful use in imaging of CNS disorders, recently used in imaging the pelvis as well [2]. Different bleeding stages produce different products like methemoglobin in subacute blood products, as well as deoxyhemoglobin and hemosiderin in acute and chronic blood products respectively, all cause local magnetic field inhomogeneity in Susceptibility Weighted Image and so detected as signal drop [3].
SWI is highly sensitive for detecting products of hemorrhage within various gynecologic pathologies and helpful for the differential diagnosis such as: Gynecological disorders associated with bleeding pathology like: hemorrhagic ovarian cysts, ovarian cancers endometriosis, hemorrhagic uterine pathologies (cancers, adenomyosis with hemorrhagic foci, leiomyomas with red degeneration, with hemorrhagic necrosis, and Placental polyp with hemorrhagic foci) are now detected more easily without the need to do extra sequences like T1-fat sat owing to the great sensitivity and specificity [3].
One of the most common challenging causes of infertility is endometriosis while its early detection helps in nearly complete and proper treatment of infertility, its late diagnosis affecting young females by repeated cyclic hemorrhage and rupture leading to adhesions leading to difficulty treated infertility. Here, we can appreciate how much the great value of SWI in early detection and proper treatment of endometriosis [4].
SWI help in diagnosing atypical cases. Because typical MRI appearance include: hyperintense T1WI cysts and/or hypointense T2WI cyst (shading). However, solid endometriomas do not meet these criteria (seen as solid masses not cysts), and it could be difficult to differentiate from other ovarian cystic masses.
SWI detect it as homogenous signal void lesions [4].
Extra-ovarian endometriosis such as broad ligament, pelvic wall, caesarian section scar, urinary bladder, abdominal wall, endometriosis. etc. Could be confused with metastasis/other tumors due to their multiplicity when detected by the conventional MRI sequences (T1, T2). However, SWI can easily detect them as foci of signal voids or homogenous signal drop due to hemosiderin deposition without any confusion [2]. Open Journal of Medical Imaging SWI is highly comparative to conventional MRI sequences showing great and significant difference in sensitivity for detecting bleeding products as SWI can detect even minimal amount of bleeding products in any stage which not the same in conventional MRI sequences [3].
Differentiating focal adenomyosis from physiologic contraction become easy task by SWI which shows adenomyosis with punctate signal voids of hemosiderin deposition scattered within adenomyosis, this not the case in contraction. [4].
Red degeneration is a hemorrhagic infarction of uterine fibroid seen during pregnancy, or with use of oral hormonal contraceptive pills that considered most sever complication. The paramagnetic methemoglobin within thrombosed veins seen as hyperintense rim on T1WI. In the other hand SWI can detect this rim at early phase as signal void due to the blooming effect of deoxyhemoglobin which cannot be done by T1WI [5]. We include patients with Hemorrhagic ovarian cysts, Endometriosis, ovarian cancers, cancer cervix, extraovarian endometriotic implants (peritoneal. scar, anterior abdominal wall), Hemorrhagic Uterine pathologies (Adenomyosis with hemorrhagic foci, and Leiomyomas with red degeneration and hemorrhagic necrosis). All patients enrolled in the study, have normal renal function tests (Table 2).

Subjects and Methods
We exclude patients with ferromagnetic or electronically operated active devices like automatic cardioverter defibrillators, cardiac pacemakers, cochlear implants and Patients with high renal function tests.
Examinations were performed regardless of the stage of the menstrual cycle with no bowel preparation or intraluminal opacification of bowel or vagina will be used.
Images was acquired on a 1.5T MR scanner equipped with an 8-channel pelvic coil. Standard pelvic MRI protocol including three projections: axial, sagittal, and coronal T2-and T1-pulse sequences before and after fat-suppression and gadolinium IV contrast.
The additional time for SWI sequence is approximately 3 min. SWI sequences consisting of magnitude and phase images will be obtained in axial planes.
All images were reviewed on PACS (picturing archiving and communication system) workkstation and lesions were evaluated regarding their location, signal intensity on T1W and T2W images, and presence of signal void on SWI. The lesion signal intensity will be considered hypointense or hyperintense compared to the signal intensity of adjacent pelvic muscles.         Table 3: Distribution of gynecologic diseases according to their T1, T2, SWI and known cases with hemorrhage shows positive T1 signal intensity (50%), T2 signal intensity (33.3%), SWI (75%) by MRI and Known cases with hemorrhage (79.1%). Figure 3: Shows highly statistically significant agreement between SWI and known cases with hemorrhage among studied group. Figure 4: Diagnostic performance of known cases with hemorrhage in reference to T1 signal intensity by MRI, Sensitivity 57.9%, specificity 80.0%, positive predictive value 91.6%, negative predictive value 33.3% and accuracy 62.5%. Figure 5: Diagnostic performance of known cases with hemorrhage in reference to SWI, sensitivity 94.7%, specificity 100.0%, positive predictive value 100.0%, negative predictive value 83.3% and accuracy = 95.8%.

Case Presentations
Case 1, Figure 6 & Figure 7: a 26-year-old female patient complaining of pelvic pain. Ultrasound showed bilateral ovarian cysts for MRI assessment, and the final diagnosis was bilateral endometriomas.
Case 2, Figure 8 & Figure 9: a 50-year-old female patient with of pelvic pain and mass sensation, ultrasound examination shows bilateral ovarian cysts, and the final diagnosis was bilateral endometriomas. Case 3, Figure 10 & Figure 11: a 53-year-old female patient with recurrent vaginal bleeding, and the final diagnosis was cancer cervix with scattered foci of microbleeds.

Discussion
SWI is superior to conventional MRI sequences T1, T2 weighted images as SWI is greatly sensitive for showing blood products and venous vasculature being complementary to conventional sequences. Good pathologic correlations were found for blood products as predicted by SWI [6].
The current study was done to highlight the diagnostic value of SWI in various gynecological diseases that contain hemorrhagic products in comparison to conventional sequences (T1 and T2 WIs).
48 patients of (17 -60 y.o) age groups were tested with ovarian and ex-

Conclusion
SWI is an excellent MRI sequence showing great sensitivity and accuracy in the evaluation of different pathologies related to the gynecologic diseases that contain hemorrhagic products. SWI is superior to conventional MRI in assessing hemosiderin deposition which makes it of more value than conventional MRI or Ultrasonography.

Ethics Statement
The study was approved by the Ethics Board of Benha University.