Endometrial cysts of the ovary: MR imaging

Comparison of Benign, Borderline, and Malignant Ovarian Seromucinous Neoplasms on MR Imaging

PURPOSE

This study aimed to compare MRI findings among benign, borderline, and malignant ovarian seromucinous neoplasms.

METHODS

We retrospectively analyzed MRI data from 24 patients with ovarian seromucinous neoplasms-seven benign, thirteen borderline, and six malignant. The parameters evaluated included age, tumour size, morphology, number, height, apparent diffusion coefficient (ADC) values, T2 ratios, time-intensity curve (TIC) descriptors, and TIC patterns of the mural nodules. Additionally, we examined the T2 and T1 ratios of the cyst contents, tumour markers, and the presence of endometriosis. We used statistical tests, including the Kruskal-Wallis and Fisher-Freeman-Halton exact tests, to compare these parameters among the three aforementioned groups.

RESULTS

The cases showed papillary architecture with internal branching in 57% of benign, 92% of borderline, and 17% of malignant cases. Three or fewer mural nodules were seen in 57% of benign, 8% of borderline, and 17% of malignant cases. Compared to benign and borderline tumours, mural nodules of malignant neoplasms had significantly increased height (P = 0.015 and 0.011, respectively), lower means ADC values (P = 0.003 and 0.035, respectively). The mural nodules in malignant cases also demonstrated significantly lower T2 ratios than those in the benign cases (P = 0.045). Most neoplasms displayed an intermediate-risk TIC pattern, including 80% benign, 83% borderline, and 60% malignant neoplasms, and no significant differences were observed.

CONCLUSION

Most benign and borderline tumours exhibited a papillary architecture with an internal branching pattern, whereas this feature was less common in malignant neoplasms. Additionally, benign tumours had fewer mural nodules compared to borderline tumours. Malignant neoplasms were characterized by mural nodules with increased height and lower ADC values than those in benign and borderline tumours. Interestingly, all three groups predominantly exhibited an intermediate-risk TIC pattern, emphasizing the complexity of diagnosing seromucinous neoplasms using MRI.

T1 relaxation: Chemo-physical fundamentals of magnetic resonance imaging and clinical applications

A knowledge of the complex phenomena that regulate T1 signal on Magnetic Resonance Imaging is essential in clinical practice for a more effective characterization of pathological processes. The authors review the physical basis of T1 Relaxation Time and the fundamental aspects of physics and chemistry that can influence this parameter. The main substances (water, fat, macromolecules, methemoglobin, melanin, Gadolinium, calcium) that influence T1 and the different MRI acquisition techniques that can be applied to enhance their presence in diagnostic images are then evaluated. An extensive case illustration of the different phenomena and techniques in the areas of CNS, abdomino-pelvic, and osteoarticular pathology is also proposed. CRITICAL RELEVANCE STATEMENT: T1 relaxation time is strongly influenced by numerous factors related to tissue characteristics and the presence in the context of the lesions of some specific substances. An examination of these phenomena with extensive MRI exemplification is reported. KEY POINTS: The purpose of the paper is to illustrate the chemical-physical basis of T1 Relaxation Time. MRI methods in accordance with the various clinical indications are listed. Several examples of clinical application in abdominopelvic and CNS pathology are reported.

Endometriosis, a common but enigmatic disease with many faces: current concept of pathophysiology, and diagnostic strategy

Endometriosis is a benign, common, but controversial disease due to its enigmatic etiopathogenesis and biological behavior. Recent studies suggest multiple genetic, and environmental factors may affect its onset and development. Genomic analysis revealed the presence of cancer-associated gene mutations, which may reflect the neoplastic aspect of endometriosis. The management has changed dramatically with the development of fertility-preserving, minimally invasive therapies. Diagnostic strategies based on these recent basic and clinical findings are reviewed. With a focus on the presentation of clinical cases, we discuss the imaging manifestations of endometriomas, deep endometriosis, less common site and rare site endometriosis, various complications, endometriosis-associated tumor-like lesions, and malignant transformation, with pathophysiologic conditions.

Differentiation of Endometriomas from Ovarian Hemorrhagic Cysts at Magnetic Resonance: The Role of Texture Analysis

Background and Objectives: To assess ovarian cysts with texture analysis (TA) in magnetic resonance (MRI) images for establishing a differentiation criterion for endometriomas and functional hemorrhagic cysts (HCs) that could potentially outperform their classic MRI diagnostic features. Materials and Methods: Forty-three patients with known ovarian cysts who underwent MRI were retrospectively included (endometriomas, n = 29; HCs, n = 14). TA was performed using dedicated software based on T2-weighted images, by incorporating the whole lesions in a three-dimensional region of interest. The most discriminative texture features were highlighted by three selection methods (Fisher, probability of classification error and average correlation coefficients, and mutual information). The absolute values of these parameters were compared through univariate, multivariate, and receiver operating characteristic analyses. The ability of the two classic diagnostic signs ("T2 shading" and "T2 dark spots") to diagnose endometriomas was assessed by quantifying their sensitivity (Se) and specificity (Sp), following their conventional assessment on T1-and T2-weighted images by two radiologists. Results: The diagnostic power of the one texture parameter that was an independent predictor of endometriomas (entropy, 75% Se and 100% Sp) and of the predictive model composed of all parameters that showed statistically significant results at the univariate analysis (100% Se, 100% Sp) outperformed the ones shown by the classic MRI endometrioma features ("T2 shading", 75.86% Se and 35.71% Sp; "T2 dark spots", 55.17% Se and 64.29% Sp). Conclusion: Whole-lesion MRI TA has the potential to offer a superior discrimination criterion between endometriomas and HCs compared to the classic evaluation of the two lesions' MRI signal behaviors.

Deep infiltrating endometriosis: Can magnetic resonance imaging anticipate the need for colorectal surgeon intervention?

OBJECTIVE

To identify magnetic resonance imaging (MRI) features associated with colorectal surgical bowel resection for treatment of deep infiltrating endometriosis (DIE).

MATERIALS AND METHODS

122 preoperative pelvic MRIs in women with laparoscopically-proven DIE and subsequent surgery (2006-2015) were identified, and retrospective cohort analysis performed. MRIs were reviewed independently by two radiologists blinded to surgical/histopathological outcomes. Associations between MRI characteristics of middle/posterior compartment endometriosis and surgical outcomes were investigated to identify MRI features associated with colorectal surgical bowel resection.

RESULTS

MRI features associated with colorectal surgical intervention were: presence of an MRI bowel lesion (sensitivity 95.3%, specificity 63.3%, ROC-AUC 0.79); MRI bowel lesions ≥20 mm in length (sensitivity 91%, specificity 77%, ROC-AUC 0.84); MRI bowel lesions invading the muscularis or submucosa/mucosa layers (sensitivity 95.3%, specificity 63.3%, ROC-AUC 0.90).

CONCLUSION

This study identifies MRI features that have potential diagnostic utility in identifying the need for colorectal surgical intervention in patients with DIE.

Factors that Differentiate between Endometriosis-associated Ovarian Cancer and Benign Ovarian Endometriosis with Mural Nodules

Purpose:

Mural nodules and papillary projections can be seen in benign ovarian endometriosis (OE) and malignant transformation of OE (endometriosis-associated ovarian cancer [EAOC]), which can pose a challenging diagnostic dilemma to clinicians. We identify the preoperative imaging characteristics helpful to the differential diagnosis between benign OE with mural nodules and EAOC.

Materials and Methods:

This was a retrospective study of 82 patients who were diagnosed pathologically to have OE with mural nodules (n = 42) and malignant transformations of these tumors (n = 40) at the Nara Medical University Hospital from January 2008 to January 2015. All patients were assessed with contrast-enhanced MRI before surgery. Patient demographics, and clinical and pathologic features were analyzed to detect the significant differences between the two groups.

Results:

Histological examinations of resected OE tissue specimens revealed that a majority (78.6%) of the mural nodular lesions were retracted blood clots. We found that the patients with malignant mural nodules, when compared to those with benign nodules, were older, had larger cyst diameters and larger mural nodule sizes, and were more likely to exhibit a taller than wider lesion. They were also more likely to present with various signal intensities on T₁-weighted images (T₁WI), high-signal intensity on T₂-weighted images (T₂WI), a lower proportion of shading on T₂WI, and were more likely to show an anterior location of the cyst. In the multivariate logistic regression analysis, “Height” (>1.5 cm) and “Height-Width ratio (HWR)” (>0.9) of mural nodules, maximum diameter of the cyst (>7.9 cm), and age at diagnosis (>43 years) were independent predictors to distinguish EAOC from OE with mural nodules.

Conclusion:

The “Height” and “HWR” of the mural nodules in the cyst may yield a novel potential diagnostic factor for differentiating EAOC from benign OE with mural nodules.

A case of small intestinal endometrioid adenocarcinoma

Endometriosis generally occurs in the ovary. Intestinal endometriosis is rare. About 1 % of all endometriosis cases become malignant. Malignant transformation of small intestinal endometriosis is very rare. A 55-year-old woman who underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy and omentectomy for endometriosis 7 years ago presented to her primary care doctor with melena. A tumor was detected in the right lower abdomen by ultrasonography. The doctor referred her to our hospital. Computed tomography demonstrated a lobulated tumor ventral to the right common iliac vessels. Magnetic resonance imaging demonstrated that the tumor had heterogeneous intensity on T2-weighted images. Several small cysts with high intensity were observed caudal to the tumor on T2-weighted images. We performed partial small intestinal resection for the lesion. The tumor was diagnosed as endometrioid adenocarcinoma of the small intestine. She has been relapse-free for 5 years after surgery. Only three cases of malignant transformation of small intestinal endometriosis have been reported previously. It is very rare for long-term survival to be obtained with surgery alone, as in our case. This case report highlights the imaging findings for malignant transformation of intestinal endometriosis.

The shading sign: is it exclusive of endometriomas?

OBJECTIVES

To investigate if the shading sign is an exclusive MRI feature of endometriomas or endometrioid tumors, and to analyze its different patterns.

METHODS

Three hundred and fourty six women with adnexal masses who underwent 1.5/3-T MRI were included in this retrospective, board-approved study. The shading sign was found in 56 patients, but five cases were excluded due to lack of imaging follow-up or histological correlation. The final sample included 51 women. The type of tumor and the pattern of shading were recorded for each case.

RESULTS

Thirty endometriomas and five endometrioid carcinomas were found. The remaining 16 cases corresponded to other benign and malignant tumors. The overall sensitivity, specificity, positive predictive value, and negative predictive value were 73%, 93%, 59%, and 96%, respectively. Restricting the analysis to cystic lesions without solid or fat component, sensitivity, specificity, positive predictive value, and negative predictive value were 73%, 96%, 94%, and 80%. Five shading patterns were identified: layering (15.7%), liquid-liquid level (11.8%), homogenous (45.1%), heterogeneous (11.8%), and focal/multifocal shading within a complex mass (19.6%). No significant correlation was found between these patterns and the type of tumor.

CONCLUSIONS

The shading sign is not exclusive of endometriomas or endometrioid tumors. Homogenous shading was the most prevalent pattern in endometriomas and half of the cases with focal/multifocal shading within a complex mass were endometrioid carcinomas.

Use of enhanced T2 star-weighted angiography (ESWAN) and R2* values to distinguish ovarian cysts due to endometriosis from other causes

PURPOSE

To evaluate the feasibility of enhanced T2 star-weighted angiography (ESWAN) in differentiating endometrial from non-endometrial cysts.

METHODS

Forty-nine patients with 60 histopathologically proven ovarian cystic lesions underwent pelvic MRI including T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), liver acquisition with volume acceleration, and ESWAN. Ovarian cystic lesions were divided into endometrial cysts (group 1; n = 28), pyosalpinx and hydrosalpinx (group 2; n = 13), and ovarian cystic and cystic-solid tumors (group 3; n = 19). R2* (effective transverse relaxation rate) values were measured and pairwise comparison of the R2* values among the three groups was made using Kruskal-Wallis test. Receiver operating characteristic curves were used to calculate cutoff values and performance of R2* values for distinguishing among groups. T1WI signal intensity and R2* value were also compared using area under curve values.

RESULTS

R2* values for group 1 were statistically higher than groups 2 and 3 (15.37, 1.40, and 1.79 Hz, respectively; P < 0.001). The cutoff value for R2* was 7.43 Hz with a sensitivity, specificity, PPV, NPV, and accuracy of 96.43, 87.50, 87.10, 96.55, and 91.67%, respectively. There was no significant difference between the R2* value and T1WI in diagnosing endometrial cysts.

CONCLUSIONS

The R2* value provides an effective way to discriminate endometrial cysts from other ovarian cystic lesions.

Differentiation of epithelial ovarian cancer subtypes by use of imaging and clinical data: a detailed analysis

Background

Primary epithelial ovarian carcinoma is sub-classified into serous, mucinous, endometrioid and clear cell subtypes. Neoadjuvant chemotherapy has become an alternative treatment option past several years, as serous carcinoma, the most common subtype, is known as chemotherapy-sensitive tumor. On the other hand, mucinous and clear cell carcinoma are known as chemotherapy-resistive. Therefore, it may be meaningful to estimate subtype of ovarian carcinoma using imaging modality. The purpose of this study is to study whether CT or MRI can determine the subtypes of epithelial ovarian cancers.

Methods

The imaging and clinical findings obtained from 125 consecutive patients with primary ovarian carcinoma were retrospectively analyzed. Forty-four of the patients had serous carcinoma; 13, mucinous carcinoma; 53, clear cell carcinoma; and 15, endometrioid carcinoma. We studied the bilateralism, morphological type, tumor diameter, solid portion ratio, relative signal intensity on T2WI and DWI, contrast ratio, and endometriosis on MRI and the calcification, peritoneal dissemination and lymph node metastasis, clinical staging, and thromboembolism on CT. We also studied the tumor markers and serum calcium concentrations. Each parameter was statistically analyzed by univariate and multivariate analyses.

Results

Serous carcinoma showed a significantly higher incidence of bilateral disease, smaller tumor size, higher signal intensity on DWI, and less frequent hypercalcemia. The CA19-9 level was significantly higher in mucinous carcinoma, in which most of the tumors appeared as multilocular cystic masses. Clear cell carcinoma appeared as unilateral disease with a larger solid portion and hypercalcemia in younger patients. Endometrioid carcinoma only showed a lower incidence of intraperitoneal dissemination.

Conclusions

CT and MRI combined with clinical data especially tumor markers and presence of paraneoplastic syndrome could partly predict epithelial ovarian cancer subtypes.

Clear cell carcinoma arising from a uterus-like mass

A uterus-like mass is an extrauterine mass with a cavity lined by endometrial tissue and a smooth muscle layer resembling the uterine corpus. It is a rare condition of unknown histogenesis. Herein, we describe a case of clear cell carcinoma arising from a uterus-like mass located in the retroperitoneal space. The patient, a 67-year old nulliparous woman, had been followed with the diagnosis of an ovarian endometriotic cyst for 14 years until ultrasonography and magnetic resonance imaging (MRI) demonstrated an enlargement of the cystic mass with a thickened irregular wall. Suspicion of malignant transformation prompted us to excise the lesion. At laparotomy, the uterus and right ovary appeared normal, and a mass measuring 8 cm was identified in the retroperitoneal space without any connection to the uterus. Grossly, the removed mass was composed of a cyst filled with blackish-brownish fluid and a thick wall resembling uterine myometrium. Microscopically, endometrial tissue inside the cyst, which was diffusely lined by clear cell carcinoma, was identified. Although the histogenesis of a uterus-like mass remains unclear, this case indicates that malignant tumors may occur from a uterus-like mass through the pathway similar to the carcinogenesis of endometriosis-related ovarian neoplasms.

Location-dependent value of pelvic MRI in the preoperative diagnosis of endometriosis

OBJECTIVES

To investigate the value of magnetic resonance imaging (MRI) in the preoperative diagnosis of specific anatomical locations of endometriosis.

STUDY DESIGN

Between July 2008 and April 2011, 152 women (mean age 33.5 ± 6.1 years) with clinical and sonographic suspicion of endometriosis underwent pelvic MRI using T2 and unenhanced T1 sequences with and without fat saturation. Two radiologists interpreted the following regions by consensus according to a standardized protocol: ovaries, vagina, pouch of Douglas, rectosigmoid colon, uterosacral ligament (USL), bladder, peritoneum, and other pelvic regions. The results of MRI were retrospectively correlated with the laparoscopic and histopathologic findings. The main outcome parameters, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, positive likelihood ratio (LR+) and the negative likelihood ratio (LR-), were determined.

RESULTS

Sensitivity, specificity, PPV, NPV, accuracy, positive and the negative likelihood ratio were 87.6%, 84.6%, 94.3%, 70.2%, 86.8%, 5.69 and 0.15 for the pouch of Douglas (vagina: 81.4%, 81.7%, 79.2%, 83.8%, 81.6%, 4.45, 0.23; rectosigmoid colon: 80.2%, 77.5%, 80.2%, 77.5%, 78.9%, 3.56, 0.25; USL: 77.5%, 68.2%, 77.5%, 68.2%, 73.7%, 2.44, 0.33; ovaries: 86.3%, 73.6%, 78.4%, 82.8%, 80.3%, 3.27, 0.19; urinary bladder: 81.0%, 94.7%, 70.8%, 96.9%, 92.8%, 15.15, 0.20; peritoneum: 35.3%, 88.1%, 60.0%, 73.0%, 70.4%, 2.97, 0.73). All endometriotic implants at other localization were detected (abdominal wall in 4, groin in one patient).

CONCLUSIONS

The value of MRI in preoperative diagnosis of endometriosis is dependent on the location of endometriosis. The highest accuracy was found in bladder endometriosis and the lowest in peritoneal endometriosis.

ESUR guidelines for MR imaging of the sonographically indeterminate adnexal mass: an algorithmic approach

A significant proportion of adnexal masses detected by sonography are indeterminate. Either their organ of origin is uncertain or it is unclear whether their nature is benign or malignant. MR imaging of the sonographically indeterminate adnexal mass can resolve most of these uncertainties. Most indeterminate masses result from common benign conditions and women with such masses can avoid unnecessary or inappropriate surgery. For the minority of women whose masses are malignant, use of MR imaging rather than a 'wait and watch' strategy of repeat ultrasound (US) results in a more timely diagnosis. There are simple diagnostic steps in the MR imaging assessment which direct an algorithmic and problem-solving approach based on signal characteristics and morphology. MR imaging should provide a more timely diagnosis and, thereby, guide the management of the patient with reduced costs of investigation and treatment.

Female infertility: a systematic approach to radiologic imaging and diagnosis

Imaging plays a key role in the diagnostic evaluation of women for infertility. The pelvic causes of female infertility are varied and range from tubal and peritubal abnormalities to uterine, cervical, and ovarian disorders. In most cases, the imaging work-up begins with hysterosalpingography to evaluate fallopian tube patency. Uterine filling defects and contour abnormalities may be discovered at hysterosalpingography but typically require further characterization with hysterographic or pelvic ultrasonography (US) or pelvic magnetic resonance (MR) imaging. Hysterographic US helps differentiate among uterine synechiae, endometrial polyps, and submucosal leiomyomas. Pelvic US and MR imaging help further differentiate among uterine leiomyomas, adenomyosis, and the various müllerian duct anomalies, with MR imaging being the most sensitive modality for detecting endometriosis. The presence of cervical disease may be inferred initially on the basis of difficulty or failure of cervical cannulation at hysterosalpingography. Ovarian abnormalities are usually detected at US. The appropriate selection of imaging modalities and accurate characterization of the various pelvic causes of infertility are essential because the imaging findings help direct subsequent patient care.

MR Imaging of Gynecologic Diseases at 3T

MR imaging using anatomic, chemical, and functional information offers huge potential for the management of the gynecologic patient. By differentiating benign from malignant disease with very high specificity, it can aid the selection of patients requiring further treatment and determine the level of urgency. Staging accuracy, which equals that obtained at laparotomy, allows appropriate clinical expertise to be organized before surgery or the deferment of surgery until later in the treatment pathway and is a cost-effective use of resources. This article compares and contrasts MR imaging of gynecologic conditions at 1.5 and 3T and defines a role for high field imaging for these clinical conditions.

Accuracy of magnetic resonance imaging and rectal endoscopic sonography for the prediction of location of deep pelvic endometriosis

BACKGROUND

We compared the accuracy of magnetic resonance imaging (MRI) and rectal endoscopic sonography (RES) for the diagnosis of deep pelvic endometriosis (DPE), with respect to surgical and histological findings.

METHODS

Longitudinal study of 88 consecutive patients referred for surgical management of DPE, who underwent both MRI and RES pre operatively. The diagnostic criteria were identical for MRI and RES and were based on visualization of hypointense/hypoechoic areas in specific locations. DPE was diagnosed when at least one site was involved. We calculated the sensitivity, specificity, predictive values, accuracy and 95% confidence interval of MRI and RES for DPE.

RESULTS

DPE and endometriomas were present in 97.7 and 39.7% of women, respectively. The sensitivity, specificity and positive and negative predictive values of MRI and RES, respectively, were 84.8 and 45.6%, 88.8 and 40%, 98.5 and 87.8% and 40 and 8.5% for uterosacral endometriosis; 77.7 and 7.4%, 70% and 100, 85.3 and 100% and 89.7 and 70.9% for vaginal endometriosis and 88.3 and 90%, 92.8 and 89.3%, 96.4 and 94.7% and 78.8 and 80.6% for colorectal endometriosis.

CONCLUSIONS

MRI is more accurate than RES for the diagnosis of uterosacral and vaginal endometriosis, whereas the two methods are similarly accurate for colorectal endometriosis.

Posterior cul-de-sac obliteration associated with endometriosis: MR imaging evaluation

PURPOSE

To retrospectively evaluate the accuracy of magnetic resonance (MR) imaging in depicting posterior cul-de-sac obliteration in patients with endometriosis.

MATERIALS AND METHODS

Institutional review board approval was not required for this retrospective study, but informed consent was obtained from all patients. MR images obtained between January 1989 and December 2000 in 57 women (mean age, 39 years; age range, 26-52 years) with histologically confirmed endometriosis were retrospectively evaluated by four radiologists independently. All patients underwent laparotomy or laparoscopy less than 1 month after MR imaging. MR images were evaluated for the presence and location of endometrial implants and adhesions. MR images were also scored for the presence of five findings: retroflexed uterus, elevated posterior vaginal fornix, intestinal tethering or tethered appearance of rectum in direction of uterus, faint strands between uterus and intestine, and fibrotic plaque or nodule covering serosal surface of the uterus. Interobserver agreement for each of the five findings and for the overall diagnosis of cul-de-sac obliteration was calculated. Sensitivity, specificity, accuracy, positive and negative predictive values, and kappa statistics were determined.

RESULTS

Laparotomy or laparoscopy revealed posterior cul-de-sac obliteration in 30 patients. Overall, the four radiologists had mean accuracies of 89.0% and 76.3% for diagnosing endometrial implants and adhesions, respectively, at MR imaging. Overall, the radiologists achieved mean sensitivity, specificity, accuracy, and positive and negative predictive values of 68.4%, 76.0%, 71.9%, 76.6%, and 68.5%, respectively, in diagnosing posterior cul-de-sac obliteration. The best accuracy (mean value, 64.5%) was obtained with the finding of fibrotic plaque in the uterine serosal surface. Readers agreed on the observations 63.2%-91.2% of the time. For the impression of the presence or absence of posterior cul-de-sac obliteration, interobserver agreement varied between substantial and moderate: Mean interobserver agreement was 78.4% (range, 70.2%-84.2%), and mean kappa was 0.57 (range, 0.40-0.67). Mean accuracy of MR imaging for diagnosing posterior cul-de-sac obliteration was 71.9%.

CONCLUSION

These results suggest that use of the described MR imaging findings may enable diagnosis of posterior cul-de-sac obliteration.

Deep pelvic endometriosis: MR imaging for diagnosis and prediction of extension of disease

PURPOSE

To prospectively evaluate the accuracy of magnetic resonance (MR) imaging for the preoperative diagnosis of deep pelvic endometriosis and extension of the disease.

MATERIALS AND METHODS

One hundred ninety-five patients (mean age, 34.2 years; range, 20-71 years) who were suspected of having pelvic endometriosis were recruited at two institutions. Two experienced radiologists evaluated the MR images independently. Deep pelvic endometriosis was defined as implants or tissue masses that appeared as hypointense areas and/or hyperintense foci on T1- or T2-weighted MR images in the following locations: torus uterinus, uterosacral ligaments (USLs), vagina, rectovaginal septum, rectosigmoid, and bladder. MR imaging results were compared with surgical and pathologic findings. Sensitivity, specificity, predictive values, and accuracy of MR imaging for prediction of deep pelvic endometriosis were assessed.

RESULTS

Pelvic endometriosis was confirmed at pathologic examination in 163 (83.6%) of 195 patients. Endometriomas, peritoneal lesions, and deep pelvic endometriosis were diagnosed on the basis of surgical findings, alone or combined with pathologic findings, in 111 (68.1%), 83 (50.9%), and 103 (63.2%) of 163 patients, respectively. Torus uterinus and USL were the most frequent sites of deep pelvic endometriosis. The sensitivity, specificity, positive and negative predictive values, and accuracy of MR imaging for deep pelvic endometriosis were 90.3% (93 of 103), 91% (84 of 92), 92.1% (93 of 101), 89% (84 of 94), and 90.8% (177 of 195), respectively. The sensitivity, specificity, and accuracy, respectively, of MR imaging for the diagnosis of endometriosis in specific sites were as follows: USL, 76% (57 of 75), 83.3% (100 of 120), and 80.5% (157 of 195); vagina, 76% (16 of 21), 95.4% (166 of 174), and 93.3% (182 of 195); rectovaginal septum, 80% (eight of 10), 97.8% (181 of 185), and 96.9% (189 of 195); rectosigmoid, 88% (53 of 60), 97.8% (132 of 135), and 94.9% (185 of 195); and bladder, 88% (14 of 16), 98.9% (177 of 179), and 97.9% (191 of 195).

CONCLUSION

MR imaging demonstrates high accuracy in prediction of deep pelvic endometriosis in specific locations.

Kinematics of the uterus: cine mode MR imaging

Cine mode magnetic resonance (MR) imaging has allowed evaluation of kinematics of the pelvis. Visualization of dynamic changes under strain facilitates evaluation of prolapses and adhesions between organs. The uterus, an organ of smooth muscle, has an inherent contractility that characterizes it as different from other visceral organs. This sustained contraction has occasionally been shown on static images as a finding masquerading as a leiomyoma or as adenomyosis. Cine mode MR imaging clearly shows the configuration of the myometrium during these dynamic changes, as well as its signal intensity during contractions. Uterine peristalsis, the subtle and rhythmic contractions of the inner myometrium, is also clearly identifiable on cine mode images as a wavy movement of the endometrium and/or inner myometrium. The direction and frequency of uterine peristalsis are different in each of the menstrual cycle phases and are thought to have important roles in uterine function, such as in fertility and menstrual blood discharge. Elucidation of these kinematics of the uterus will help in the evaluation of static MR images and study of the physiology of the uterus. Cine MR imaging is a novel technique for diagnosis and evaluation of the pelvic organs, especially the uterus.

Relationship between apparent diffusion coefficient and signal intensity in endometrial and other pelvic cysts

We evaluated whether apparent diffusion coefficient (ADC) value is more useful than signal intensity for differentiating endometrial cysts from other pelvic cysts. In an in vitro study, signal intensity and diffusion coefficients were measured in whole blood phantoms in which blood oxidation was gradually increased and concentration subsequently diluted. Although both signal intensity and diffusion value were largely affected by blood concentration, diffusion value was almost independent of blood oxidation and red blood cell lysis-related diminution of magnetic nonhomogeneity, both factors greatly affecting signal intensity on T1- and T2-weighted images. In an in vivo study, differentiation between endometrial and other pelvic cysts was attempted by means of ADC values and signal ratios of cysts to muscles on T1- and T2-weighted images (T1- and T2-ratios). Endometrial cysts tended to show lower T2-ratios, higher T1-ratios, and lower ADC values than other pelvic cysts (p < 0.001). However, ADC values were not correlated with T1- and T2-ratios (p < /0.15/). The ability of ADC value to discriminate between these two groups (discriminant rate, 91.4%) was higher than that of T2-ratio (71.4%) or T1-ratio (88.6%). If combined, ADC and T1-ratio (or T2-ratio) showed higher discriminant rate (94.3%) than the combination of T1- and T2 ratios (88.6%). ADC value might be useful for evaluating the blood concentration of a cystic lesion, because diffusion value is more closely related to blood concentration and almost independent of blood oxidation and red blood cell lysis that largely affect signal intensity.

A decidualized endometrial cyst in a pregnant woman: a case observed with a steady-state free precession imaging sequence

Decidual changes of the ectopic endometrial stroma during pregnancy are well known among pathologists and obstetricians. However, they appear very similar to endometrial cysts with malignant transformation when imaged. Balanced fast field echo (BFFE) is a steady-state free precession imaging sequence and its contrast is decided by the T1/T2 ratio. The authors report a case of a decidualized endometrial cyst in which mural nodules were isointense with the nomotopic decidualized endometrium on T1- and T2-weighted images and BFFE. Isointensity with the nomotopic endometrium is an MR characteristic that can differentiate a decidualized endometrial cyst from malignant transformation. BFFE is a good alternative sequence during pregnancy because of its shorter acquisition time and lower radiofrequency absorption.

Magnetic resonance imaging of the ovary

Magnetic resonance imaging (MRI) of the pelvis can characterize a wide variety of ovarian lesions. We discuss MRI strategies for identification and characterization of ovarian neoplasms and correlate MRI findings with lesion gross pathological and histopathological structure.

Efficacy of ethanol sclerotherapy for ovarian endometriomas

OBJECTIVE

To evaluate the efficacy and limitations of ethanol sclerotherapy for ovarian endometriomas.

METHODS

Retrospective investigation was made on 83 women with ovarian endometriomas who underwent transvaginal aspiration and ethanol sclerotherapy at Hiroshima City Hospital between 1993 and 1998. Furthermore, 30 who underwent laparoscopic cystectomy for ovarian endometriomas during the same period were investigated.

RESULTS

Of the 74 women who were followed for more than 6 months, 11 (14.9%) had recurrent cysts. The recurrence rate of laparoscopic cystectomy was 3.8% (NS). The recurrence rate of cases instilled for less than 10 min was 62.5% (5/8), and that for 10 or more than 10 min was 9.1% (6/66) (P<0.001). The recurrence rate of cases having one cyst was 7.5% (4/53) and that of cases having two or more cysts was 33.3% (7/21) (P<0.05).

CONCLUSION

Ethanol sclerotherapy is an effective and safe procedure and can be indicated for almost all ovarian endometriomas. Conduct of ethanol instillation for more than 10 min particularly for a case with a single endometrial cyst is considered most effective from the standpoint of recurrence.

Ovarian carcinoma in patients with endometriosis: MR imaging findings

OBJECTIVE

Various types of malignancy can develop in patients with endometriosis. Enhancing mural nodules have been reported as an imaging characteristic of malignant transformations. We evaluated contrast-enhanced MR imaging to determine the optimum sequence to reveal mural nodules and other characteristics of malignant transformations.

MATERIALS AND METHODS

We examined 10 patients with pathologically proven ovarian adenocarcinoma in endometriosis and 10 patients (the control group) with ovarian endometrioma suggestive of malignant transformation on the basis of sonographic findings. We analyzed the size and nature of the endometriomas in each patient. We compared four types of contrast-enhanced MR imaging to determine which sequence best revealed mural nodules.

RESULTS

In the malignant and control groups, 80% of the cysts with findings suggestive of malignant transformation showed unilateral disease or larger endometrial cysts on the suggestive side than on the contralateral side. High signal intensity on T1-weighted images and low signal intensity on T2-weighted images relative to the myometrium were observed only in two of 10 malignant endometrial cysts and in all control cysts. All malignant endometriomas had small mural nodules with low signal intensity on T1-weighted contrast-enhanced images. Only three benign endometriomas had mural nodules and none of them enhanced. The enhancement of mural nodules was easily seen on dynamic subtraction imaging.

CONCLUSION

On the basis of our findings, endometrial cysts with malignant transformation rarely show low signal intensity on T2-weighted images and usually have enhancing mural nodules. Because the enhancement of mural nodules is often difficult to evaluate on conventional T1-weighted images, dynamic subtraction imaging can be valuable.

Differential diagnosis of gynaecological "stained glass" tumours on MRI

Although multilocular cystic gynaecological masses in which the loculi show variable signal intensity on both T1 and T2 weighted images have been considered to be mucinous cystadenoma or adenocarcinoma, other gynaecological tumours can demonstrate this "stained glass" appearance. These include mature cystic teratoma, fibrothecoma, endometrioma, Brenner's tumour of the ovary and degenerated leiomyoma of the uterus, all of which may mimic mucinous tumours of the ovaries.

CT and MRI appearances of sarcomatous change in chronic pelvic endometriosis

Endometriosis is a relatively common condition in pre-menopausal women. Rarely, endometrial malignancy may arise in and co-exist with endometriosis. In this case report, the findings on CT and MRI which indicated this development are described. Multiple image-guided biopsies showed features consistent with endometriosis and the diagnosis was not confirmed histopathologically until formal laparotomy and open biopsy.

Diagnosis of endometriosis

Diagnosis of endometriosis requires careful interpretation of objective surgical and pathologic findings in the context of the patient's clinical presentation. Clinical assessment helps to identify patients at high risk of endometriosis and selects those who warrant further testing. Determination of the serum level of CA-125, and to a lesser extent, other proteins, may be helpful in evaluating selected population at risk and following the course of the disease. Selective use of imaging studies, especially ultrasound and magnetic resonance imaging, may also be helpful. Ultimately, the diagnosis of endometriosis is usually confirmed or refuted by laparoscopy, preferably performed in conjunction with histologic evaluation of excised lesions.

Distinguishing between cystic teratomas and endometriomas of the ovary using chemical shift gradient echo magnetic resonance imaging

The purpose of this study was to evaluate the efficacy of chemical shift gradient echo magnetic resonance imaging (MRI) in distinguishing between cystic teratomas and endometriomas of the ovary, using a 1.5T magnet. The study included 22 patients with 31 ovarian lesions (15 cystic teratomas and 16 endometriomas), which showed high signal intensity on T1-weighted spin echo images. Chemical shift gradient echo images with three different echo times (TE = 2.5, 4.5 and 6.5 ms) were obtained in all cases. Indices were calculated on the basis of the signal intensities of lesions on the chemical shift gradient echo images. All endometriomas had signal intensity indices of less than 2.1, while all cystic teratomas had signal intensity indices of 18.1 or greater. Chemical shift gradient echo imaging is an alternative method that is useful and simple for distinguishing between cystic teratomas and endometriomas of the ovary.

MRI in predicting the response of ovarian endometriomas to hormone therapy

OBJECTIVE

Our goal was to investigate the usefulness of MRI in predicting the response of endometriomas to hormone therapy.

MATERIALS AND METHODS

MRI and laparoscopy at the onset of treatment and follow-up MRI after 6 months of hormone therapy were performed in 21 patients with 49 endometriomas. T1- and T2-weighted images were obtained with a 1.5 T apparatus using a body coil. The lesions were divided into a responder group and a nonresponder group according to whether the lesion size decreased by > or = 50% or not.

RESULTS

With MRI, shading was seen in 25 of 27 lesions (93%) from the nonresponder group, but in only 6 of 22 (27%) from the responder group. Low SI rim was seen in 59% of the responders and 89% of the nonresponders. Multiplicity in 68% of the responders and in 85% of the nonresponders and irregularity in 41% of the responders and in 78% of the nonresponders were shown. Multiple logistic analysis revealed shading was the most important factor in prediction of the response to hormone therapy.

CONCLUSION

Shading was an important sign in evaluating the response of endometriomas to hormone therapy. MRI may assist in selecting the appropriate therapy for endometriomas.

Endometriosis: appearance and detection with conventional and contrast-enhanced fat-suppressed spin-echo techniques

Suspected pelvic endometriosis was prospectively evaluated in 31 women with T1- and T2-weighted conventional spin-echo (CSE) magnetic resonance imaging alone and in combination with T1-weighted fat-suppressed (T1FS) and gadolinium-enhanced T1FS (Gd-T1FS) spin-echo techniques. Images were grouped for interpretation and comparison as follows: (a) CSE alone, (b) CSE/T1FS, and (c) CSE/T1FS/Gd-T1FS. All patients underwent surgery within 3 months of imaging, and 21 patients were found to have endometriosis: 59 endometriomas (26 large and 33 small) and 51 sites of implants were seen. With CSE images, 23 large and six small endometriomas were detected. With CSE/T1FS images, 25 large and 14 small endometriomas were identified. With CSE/T1FS/Gd-T1FS images, 24 large and 14 small endometriomas were detected and ill-defined areas of enhancement were noted in 22 sites throughout the pelvis. These corresponded to endometriotic implants seen at surgery in 14 sites. The sensitivity, specificity, and accuracy, respectively, for the detection of endometriosis were 76%, 60%, and 71% for CSE, 86%, 50%, and 74% for CSE/T1FS, and 81%, 50%, and 71% for CSE/T1FS/Gd-T1FS images. No significant differences (P > .1) between image combinations for correctly identifying patients with and without endometriosis were seen. The difference in sensitivity between CSE and CSE/T1FS and between CSE and CSE/T1FS/Gd-T1FS images for detecting small endometriomas was significant (P = .03).

Diagnosis of pelvic endometriosis by magnetic resonance imaging using "fat-saturation" technique

OBJECTIVE

To assess the usefulness of fat-saturated magnetic resonance (MR) imaging for detecting small endometrial implants.

DESIGN

Prospective evaluation by conventional and fat-saturated MR imaging.

SETTING

Shimane Medical University Hospital, Izumo, Japan.

PATIENTS

Fifty-one consecutive patients with clinically suspected pelvic endometriosis.

INTERVENTIONS

Magnetic resonance images < 2 weeks before laparoscopy or laparotomy.

MAIN OUTCOME MEASURE

The location, number, and size of lesions.

RESULTS

Surgery revealed a normal pelvis in 5 patients, endometriosis in 44 (42 with pigmented lesions and 2 with nonpigmented lesions and adhesions), and other cystic lesions in 2. With fat-saturated MR imaging, overall sensitivity, specificity, positive predictive value, and negative predictive value were 89%, 71%, 95%, and 50%, respectively. At surgery, 122 pigmented lesions of endometriosis were detected. Conventional MR images indicated lesions of endometriosis in 74. When fat-saturated images were used, 103 lesions were detected. With conventional MR images, only one of 34 small endometrial implants (2 to 3 mm in diameter) was detected. However, the addition of fat-saturated images increased the detection rate to 15 of 34, and all lesions > 4 mm in diameter.

CONCLUSION

Conventional MR imaging for detecting small endometrial implants was improved by addition of the fat-saturation technique. Therefore, fat-saturation MR imaging is an acceptable for detecting small endometriomas.