Clinical application of susceptibility-weighted MR sequences in the female pelvis
Mayumi Takeuchi1, Kenji Matsuzaki1,2, and Masafumi Harada1

1Department of Radiology, University of Tokushima, Tokushima, Japan, 2Department of Radiological Technology, Tokushima Bunri University, Sanuki, Japan


Susceptibility-weighted (SW) magnetic resonance (MR) sequences have exquisite sensitivity to the blood products within various gynecologic pathologies, and may provide helpful information for the differential diagnosis. In this exhibit we demonstrate the role of SW sequences in diagnosing various pathologies in the female pelvis such as hemorrhagic cysts (endometrioma vs non-endometriotic cyst), extra-ovarian endometriosis and adenomyosis, gestation-associated lesions (ectopic pregnancy and retained products of conception), red degeneration of uterine leiomyoma, high-grade malignancy such as uterine sarcomas with hemorrhagic necrosis, and ovarian torsion.


Susceptibility-weighted (SW) magnetic resonance (MR) sequences such as SWI (Susceptibility-Weighted Imaging) and SWAN (T2 Star-Weighted ANgiography) visualize the magnetic susceptibility effects generated by local inhomogeneity of the magnetic field as signal voids (1-4). SW sequences are more sensitive to the susceptibility difference between tissues than conventional T2*WI and have been used in imaging of central nervous system for evaluating the hemorrhage and small vessels (1-4). Recently clinical applications of SW sequences in body imaging were also reported (5-9). Fat-saturated T1WI is sensitive for subacute hemorrhage, however, it can only detect methemoglobin as high intensity due to paramagnetic effect. SW sequences have exquisite sensitivity to the blood products such as hemosiderin and deoxyhemoglobin, and may contribute to the diagnosis of various gynecologic pathologies with fresh, chronic or obsolete hemorrhage. The purpose of this exhibit is to demonstrate the role of SW sequences in diagnosing various pathologies in the female pelvis.

Outline of Content

Punctate or curved linear signal voids along the cyst wall on SW sequences due to hemosiderin deposition as a result of repeated hemorrhages are characteristic for ovarian endometrioma, and useful sign for differentiating from non-endometriotic hemorrhagic cyst (5) (Fig. 1). The presence of signal voids due to hemosiderin deposition in extra-ovarian endometriosis (i.e. urinary bladder, bowels, abdominal wall and peritoneal implants), and in adenomyosis is also diagnostic (6-8) (Fig. 2). SW sequences are sensitive to a small amount of hemorrhagic contents, and can differentiate mucinous cysts from hemorrhagic cysts both exhibiting high signal intensity on T1WI. SW sequences can also demonstrate fresh hemorrhage, and is helpful for detecting ectopic pregnancy with hemorrhage, and retained products of conception (RPOC) with hemorrhagic foci. Red degeneration of uterine leiomyoma is hemorrhagic infarction due to venous obstruction associated with pregnancy, and characteristic high intensity rim on T1WI corresponding to strongly paramagnetic methemoglobin within obstructed veins may appear at subacute phase of red degeneration. At acute phase high intensity rim on T1WI does not appear yet, however, low intensity rim on SW sequences corresponding to deoxyhemoglobin within obstructed veins may be helpful for the early diagnosis (Fig. 3). Hemorrhagic necrosis is often observed in high-grade malignancy with coagulative necrosis due to the breakdown of tumor vasculature, and demonstrating hemorrhagic necrosis within uterine myometrial mass on SW sequences may be suggestive for uterine sarcomas because intra-tumoral hemorrhage is rare in benign leiomyomas. However, both hemorrhage and calcification may appear as signal voids on SW sequences. Benign leiomyomas may often contain calcifications, which should be differentiated from intra-tumoral hemorrhage in sarcomas. Phase image of SW sequences can distinguish between paramagnetic iron in hemorrhage and diamagnetic calcium deposits in tissue (Fig. 4). Venous thrombus within the twisted vascular pedicle of ovarian torsion may appear as peripherally situated signal voids on SW sequences. This finding may be feasible for the diagnosis of ovarian torsion, particularly for the lesions with subacute or chronic course in which clinical diagnosis of torsion is difficult (9) (Fig. 5).


SW sequences, which can be easily added to the routine MR examination protocol, are sensitive for the presence of hemorrhage within various gynecologic pathologies and may provide helpful information for the differential diagnosis.


No acknowledgement found.


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Fig. 1: Endometrioma vs Non-endometriotic cyst:

Both endometrioma and non-endometriotic cyst (mucinous cystic tumor) appeared as solitary, high signal intensity mass on T1- and T2WI. On SWI curved linear signal voids along the cyst wall due to hemosiderin deposition suggested endometrioma. No signal void was observed within the wall of non-endometriotic cyst.

Fig. 2: Extra-ovarian Endometriosis:

Extra-ovarian endometriosis appearing as solid masses in the abdominal wall and in the bladder wall. Low signal intensity areas on SWI were more prominent than high signal intensity areas on fsT1WI.

Fig. 3: Red degeneration of uterine leiomyoma:

On T1WI characteristic high signal intensity rim of uterine leiomyoma with red degeneration was observed at subacute phase, and not at acute phase. On SWI low signal intensity rim was observed at both subacute and acute phases.

Fig. 4: Intra-tumoral hemorrhage in uterine sarcoma:

Intra-tumoral hemorrhagic foci were observed as low intensity areas on SWAN, whereas high signal intensity area was not obvious on T1WI. On the phase image hemorrhagic foci appeared as high signal intensity areas, which were distinguishable from low intensity calcifications.

Fig. 5: Venous thrombus within twisted vascular pedicle of ovarian torsion:

Venous thrombus within the twisted vascular pedicles showed tumor-like high signal intensity on T2WI and on DWI, however, prominent signal voids on SWI/SWAN suggested the presence of blood products as venous thrombus.

Proc. Intl. Soc. Mag. Reson. Med. 24 (2016)