Primary Exploration Of Ovarian Endometriosis Cyst Diagnosis Value On SWI

Objective To explore the characteristic of the ovarian endometriosis cyst on the susceptibility weighted imaging (SWI), assess the value of differential diagnosis between ovarian endometriosis cyst and other ovarian cystic lesions on SWI.Methods Retrospectively analyzed30ovarian cystic lesions which were proved by pathology during the period from May to November in2012, including12ovarian endometriosis cysts (a total of16lesions) and18other ovarian cystic lesions. All patients underwent MRI and SWI examinations. The images were assessed. Observed contents included:single and double side of the lesion, single or multiple, shape and size; signal characteristic of cyst, presence of layers; smooth or coarse of the cyst wall, thickness and signal characteristic of the cyst wall; the characteristic of septum; clear or fuzzy with the adjacent tissue. On Siemens Leonard workstation, functool software package of the corrected phase image was used to measure the corrected phase value. According to MRI characteristic,16ovarian endometriosis cysts were divided into three groups. Compared the corrected phase value of three groups with different signal, multiple means comparison analysis of variance was applied to explore the statistical significance. Compared corrected phase value between ovarian endometriosis cysts and other ovarian cystic lesions. Two independent sample approximate t test was applied to explore the statistical significance. Compared the number of cases which were diagnosed correctly between MRI and SWI combined with MRI, Fisher probabilities method in2×2table data was applied to explore the statistical significance. P<0.05is significant. All the statistical analysis was finished by SPSS16.0. Results MRI performance of ovarian endometriosis cysts:①The signal of cyst:7lesions that had high signal intensity on T1WI, low signal intensity on T2WI;3lesions that had high signal intensity both on T1WI and T2WI;5lesions that had low signal intensity on T1WI, high signal intensity on T2WI; Layer was visible in1lesion.②Cystic wall and edge:1cyst was ruptured, its cystic wall was thick and not whole; the cystic walls of other15lesions were thin and smooth.③Septum:There was septum in2lesions; there was not septum in14lesions. The corrected phase value of three groups of ovarian endometriosis cysts were7.39±3.16,8.90±3.56,6.84±3.35. No statistical significance was observed between three groups (P>0.05). The corrected phase value of endometriosis cyst was7.625±3.073, the value of other ovarian cystic lesions was11.08±6.547, a significant difference between two groups was observed (P=0.023). SWI images showed punctuate and curved linear signal voids along cyst wall in16ovarian endometriosis cysts, signal void was not observed in other cystic lesions. The corrected diagnosed lesions of SWI combined with MRI were16, the corrected diagnosed lesions of MRI were11, a significant difference between two diagnose methods was observed (P=0.043).Conclusions (1) Punctuate and curved linear signal voids along cyst wall were visualized on SWI in ovarian endometriosis cyst, because of hemosiderin deposition, it was a feature of ovarian endometriosis cyst.(2) The corrected phase value had reference value for the diagnosis of ovarian endometriosis cyst.(3) SWI combined with MRI could improve the diagnosis rate of ovarian endometriosis cyst. SWI was useful supplement to conventional MRI imaging.