MR imaging of the uterus: low-signal-intensity abnormalities of the endometrium and endometrial cavity

Differentiation of the various lesions causing an abnormality of the endometrial cavity using MR imaging: emphasis on enhancement patterns on dynamic studies and late contrast-enhanced T1-weighted images

The objectives of this study were to determine the usefulness of magnetic resonance (MR) imaging in the differentiation of various lesions causing an abnormality of the endometrial cavity by evaluating the imaging features on dynamic contrast-enhanced study and late contrast-enhanced T1-weighted images (T1WI). Contrast-enhanced MR imaging of 59 pathologically proven lesions that showed an abnormality of the endometrial cavity, including 32 endometrial cancers, five sarcomas, nine hyperplastic polyps, nine submucosal myomas, three hyperplasia, and one adenomyoma, were retrospectively reviewed. The enhancement degree and patterns on dynamic contrast-enhanced study and late contrast-enhanced T1WI were compared among different pathologies. On dynamic contrast-enhanced study, 72% (23/32) of endometrial cancers showed early peak enhancement to be reached within 1 min following intravenous administration of contrast material. On late-contrast-enhanced T1WI, lesions showed weak enhancement with gradual washout. Ninety-five percent (21/22) of benign lesions and 100% (5/5) of sarcomas showed late peak enhancement to be reached in 2-3 min following intravenous administration of contrast material. On late contrast-enhanced T1WI, both of these lesions showed persistent strong enhancement. Different enhancement patterns on dynamic contrast-enhanced MR imaging and late contrast-enhanced T1WI can provide a useful clue in the differentiation of various lesions causing an abnormality of the endometrial cavity.

Evaluation of the uterine cavity with magnetic resonance imaging, transvaginal sonography, hysterosonographic examination, and diagnostic hysteroscopy

OBJECTIVE

To evaluate and compare the diagnostic accuracy of magnetic resonance imaging (MRI), transvaginal ultrasonography (TVS), hysterosonographic examination (HSE), and hysteroscopy in the evaluation of the uterine cavity.

DESIGN

Independent double-blind study.

SETTING

University medical hospital.

PATIENT(S)

One hundred six consecutive premenopausal women who underwent hysterectomy for benign diseases.

INTERVENTION(S)

Results of MRI, TVS, HSE, and hysteroscopy were compared with the results of histopathologic examination at hysterectomy (the gold standard).

RESULT(S)

The overall sensitivity was MRI 0.76, TVS 0.69, HSE 0.83, and hysteroscopy 0.84. The specificity was MRI 0.92, TVS 0.83, HSE 0.90, and hysteroscopy 0.88 (MRI, HSE, hysteroscopy vs. TVS <0.05). Polyps were missed in 9 of 12 cases at MRI, 7 at TVS, 4 at HSE, and 2 at hysteroscopy (MRI vs. hysteroscopy, and TVS vs. hysteroscopy <0.05). The sensitivity for identification of submucous myomas was MRI 1.0, TVS 0.83, HSE 0.90, and hysteroscopy 0.82; the specificity was MRI 0.91, TVS 0.90, HSE 0.89, and hysteroscopy 0.87 (MRI vs. TVS, and MRI vs. hysteroscopy). Magnetic resonance imaging was significantly more precise than TVS, HSE, and hysteroscopy in determining submucous myoma in-growth (2-way ANOVA <0.05).

CONCLUSION(S)

For exclusion of abnormalities in the uterine cavity, MRI, HSE, and hysteroscopy were equally effective and slightly superior to TVS. Magnetic resonance imaging and TVS missed endometrial abnormalities such as polyps, but MRI and HSE were most accurate for the evaluation of submucous myomas, and MRI was superior in evaluation of exact submucous myoma in-growth.

Abnormal uterine cavity: differential diagnosis with MR imaging

The objective of the study was to assess the usefulness of magnetic resonance (MR) imaging in distinguishing malignant from benign conditions in patients with an abnormal uterine cavity. Fifty-four patients that were suspected of having abnormal uterine cavities were retrospectively evaluated by using MR imaging. The diagnosis of an abnormal uterine cavity included a thickened endometrium, and/or a endometrial mass, and/or a submucosal mass. Threshold values to classify the uterine cavity as abnormal on sagittal T2-weighted images were >10 mm for premenopausal women and >5 mm for postmenopausal women. Malignancy was diagnosed when lesions invaded the myometrial/junctional zone, and/or lesion enhancement was lower than that of the adjacent myometrium. The results found that histology confirmed 18 malignant and 37 benign lesions. Twelve of 15 endometrial carcinomas and 3 malignant mixed mesodermal tumors (MMMT) were correctly characterized as malignant on enhanced T1-weighted images; whereas 6 of 15 endometrial carcinomas and 3 MMMT were correctly characterized on T2-weighted images. Thirty-four of 37 benign cases were correctly characterized as not malignant on enhanced T1-weighted images. One of 14 submucosal leiomyomas, one endometrial stromal metaplasia, and one of ten pathologically normal endometria were misdiagnosed on enhanced T1-weighted images but were correctly diagnosed on T2-weighted images. The overall sensitivity, specificity, and accuracy for distinguishing malignant from benign central uterine masses were 83%, 92%, and 89% for enhanced T1-weighted image, and 50%, 97%, and 82% for T2-weighted image, respectively. We came to the conclusion that in diagnosing patients with abnormal uterine cavity, MR imaging may help differentiate malignant from benign disorders.

Endometrial carcinoma: dynamic MRI with turbo-FLASH technique

PURPOSE

Our goal was to investigate the usefulness of dynamic MRI with the turbo-FLASH technique in estimating myometrial invasion by endometrial carcinoma.

METHOD

Forty-six patients with endometrial carcinomas were evaluated with pathologic correlation. Dynamic MRI was performed with the rapid administration of Gd-DTPA using the turbo-FLASH technique.

RESULTS

The inner muscle layer showed more rapid contrast enhancement effects than the outer muscle layer even after menopause. Contrast-to-noise ratio between the inner muscle layer and endometrial carcinoma was maximum at approximately 50 s after administration of Gd-DTPA. In postmenopausal women, the accuracy in estimating myometrial invasion with T2-weighted images, contrast-enhanced T1-weighted images, and dynamic MRI was 66.7, 77.8, and 92.6%, respectively.

CONCLUSION

Dynamic MRI with the turbo-FLASH technique is considered to be a useful imaging method for the estimation of myometrial invasion by endometrial carcinoma, especially in postmenopausal patients.

Quantitative MRI of the prostate and uterus in monkeys

Quantitative MRI has been carried out in the prostate, seminal vesicles, uterus, and ovaries in the pig-tailed monkey, Macaca nemestrina. T2-weighted, fat-suppressed, multislice experiments were performed at 2.35 T. Eight males, 14 ovariectomized females, and 20 intact females were studied. In the prostate, the caudal and cranial lobe were readily distinguished since the latter had a longer T2 value. For all tissues and organs, interanimal variations were large (up to 12-fold variation in volume), but reproducibility was excellent in the prostate and in the ovariectomized monkey uterus with coefficients of variation (CV) of 3 and 5%, respectively. In the intact monkey uterus, cycle-cycle reproducibility was good with CVs of 6-10% in the myometrium and 14-18% in the endometrium. In the follicular phase, endometrial growth (+3.8% day-1, P < 0.001) was accompanied by myometrial shrinkage (-1.6% day-1, P < 0.001), while in the luteal phase, growth was seen in both tissues (+4.3% day-1, P < 0.001 and +1.4% day-1, P < 0.001, respectively). The great value of these MRI techniques in obtaining data in pharmacological efficacy studies of endocrine drugs, and in limiting the number of animals used, is discussed.

Advances in gynecologic imaging and intervention

Advances in diagnostic imaging of the female genital tract facilitate characterization of many pelvic masses. Preoperative assessment of gynecologic malignant tumors provides information that may alter the surgical approach or timing of radiation therapy. Image-guided biopsy accurately confirms recurrent malignant lesions. Transcervical techniques have improved diagnostic assessment of infertile couples; thus, effective and inexpensive treatment options can be offered. Postoperative complications of gynecologic procedures can be detected with imaging, and many can be treated with image-guided techniques.