Magnetic Resonance Imaging of Benign and Malignant Uterine Neoplasms

Benign and malignant uterine masses can be seen in the women. Some of these are asymptomatic and incidentally discovered, whereas others can be symptomatic. With the soft tissue contrast resolution magnetic resonance imaging can render a definitive diagnosis, which can further help streamline patient management. In this article we show magnetic resonance imaging examples of benign and malignant masses of the uterus and their treatment strategies.

Three-Dimensional Quantitative Assessment of Uterine Fibroid Response after Uterine Artery Embolization Using Contrast-Enhanced MR Imaging

PURPOSE

To evaluate the clinical feasibility and diagnostic accuracy of three-dimensional (3D) quantitative magnetic resonance (MR) imaging for the assessment of total lesion volume (TLV) and enhancing lesion volume (ELV) before and after uterine artery embolization (UAE).

MATERIALS AND METHODS

This retrospective study included 25 patients with uterine fibroids who underwent UAE and received contrast-enhanced MR imaging before and after the procedure. TLV was calculated using a semiautomated 3D segmentation of the dominant lesion on contrast-enhanced MR imaging, and ELV was defined as voxels within TLV where the enhancement exceeded the value of a region of interest placed in hypoenhancing soft tissue (left psoas muscle). ELV was expressed in relative (% of TLV) and absolute (in cm(3)) metrics. Results were compared with manual measurements and correlated with symptomatic outcome using a linear regression model.

RESULTS

Although 3D quantitative measurements of TLV demonstrated a strong correlation with the manual technique (R(2) = 0.93), measurements of ELV after UAE showed significant disagreement between techniques (R(2) = 0.72; residual standard error, 15.8). Six patients (24%) remained symptomatic and were classified as nonresponders. When stratified according to response, no difference in % ELV between responders and nonresponders was observed. When assessed using cm(3) ELV, responders showed a significantly lower mean ELV compared with nonresponders (4.1 cm(3) [range, 0.3-19.8 cm(3)] vs 77 cm(3) [range, 11.91-296 cm(3)]; P < .01).

CONCLUSIONS

The use of segmentation-based 3D quantification of lesion enhancement is feasible and diagnostically accurate and could be considered as an MR imaging response marker for clinical outcome after UAE.

Entropy of T2-weighted imaging combined with apparent diffusion coefficient in prediction of uterine leiomyoma volume response after uterine artery embolization

RATIONALE AND OBJECTIVES

To determine the potential value of entropy of T2-weighted imaging combined with apparent diffusion coefficient (ADC) before uterine artery embolization (UAE) for prediction of uterine leiomyoma volume reduction (VR) after UAE.

MATERIALS AND METHODS

In this prospective study, 11 patients with uterine leiomyomas who underwent pelvic magnetic resonance imaging including diffusion-weighted imaging before and 6 months after UAE were included. A total number of 16 leiomyomas larger than 2 cm in diameter were evaluated. The volume of each leiomyoma before and after UAE was determined, and the percentage change in volume was calculated. Entropy of T2-weighted imaging and ADC before UAE were assessed. Pearson correction coefficients were calculated between leiomyoma VR after UAE and age, leiomyoma volume, ADC, and entropy, respectively. Multiple regression analysis was performed to investigate the parameters that determine the VR after UAE. Receiver operating characteristic curve analysis was used to determine the sensitivity and specificity of ADC, entropy and the combination of ADC and entropy for predicting volume response.

RESULTS

The mean leiomyoma VR was 58.9% (range 25.8%-95.0%) in the 6-month follow-up. The mean ADC of leiomyomas was 1.37 × 10(-3) mm(2)/s (range 1.05 × 10(-3)-2.32 × 10(-3) mm(2)/s) and the mean entropy of T2-weighted imaging was 5.36 (range 4.62-5.91) before UAE. ADC and entropy were significantly correlated with leiomyoma VR, respectively (r = 0.61, P = .012; r = 0.73, P = .001). On multiple regression analysis, a combination of ADC and entropy constituted the best model for determining leiomyoma VR using Akaike information criterion. For predicting ≥50% VR, the optimal cutoff value of ADC was 1.39 × 10(-3) mm(2)/s (sensitivity 45.5%, specificity 80.0%) and the optimal cutoff value of entropy was 5.15 (sensitivity 90.9%, specificity 60.0%). The combination of ADC and entropy (area under the curve [AUC] 0.86) provided better classification accuracy than ADC or entropy alone (AUC 0.69 and 0.82, respectively).

CONCLUSIONS

Pre-UAE entropy of T2-weighted imaging and ADC of leiomyomas were significantly correlated with the leiomyoma VR 6 months after embolization. Higher entropy and higher ADC may be related to greater leiomyoma VR after UAE. A combination of entropy and ADC may have predictive value for leiomyoma VR after UAE.

How to differentiate benign from malignant myometrial tumours using MR imaging

PURPOSE

To retrospectively evaluate the ability of magnetic resonance imaging (MRI) to differentiate malignant from benign myometrial tumours.

METHODS

Fifty-one women underwent MRI before surgery for evaluation of a solitary myometrial tumour. At histopathology, there were 25 uncertain or malignant mesenchymal tumours and 26 benign leiomyomas. Conventional morphological MRI criteria were recorded in addition to b 1,000 signal intensity and apparent diffusion coefficient (ADC). Odds ratios (OR) were calculated for each criterion. A multivariate analysis was performed to construct an interpretation model.

RESULTS

The significant criteria for prediction of malignancy were high b 1,000 signal intensity (OR = +∞), intermediate T2-weighted signal intensity (OR = +∞), mean ADC (OR = 25.1), patient age (OR = 20.1), intra-tumoral haemorrhage (OR = 21.35), endometrial thickening (OR = 11), T2-weighted signal heterogeneity (OR = 10.2), menopausal status (OR = 9.7), heterogeneous enhancement (OR = 8) and non-myometrial origin on MRI (OR = 4.9). In the recursive partitioning model, using b 1,000 signal intensity, T2 signal intensity, mean ADC, and patient age, the model correctly classified benign and malignant tumours in 47 of the 51 cases (92.4 %).

CONCLUSION

We have developed an interpretation model usable in routine practice for myometrial tumours discovered at MRI including T2 signal, b 1,000 signal and ADC measurement.

KEY POINTS

• MRI is widely used to differentiate benign from malignant myometrial tumours. • By combining T2-weighted, b 1,000 and ADC features, MRI is 92.4 % accurate. • DWI may limit misdiagnoses of uterine sarcoma as benign leiomyoma. • Patient age is important when considering a solitary myometrial tumour.

Beyond hemostasis: spectrum of gynecologic and obstetric indications for transcatheter embolization

Percutaneous vascular embolization is a useful therapeutic option for a wide range of gynecologic and obstetric abnormalities. Transcatheter embolization procedures performed with the use of radiologic imaging for guidance are minimally invasive and may obviate surgery, thereby decreasing morbidity and mortality and safeguarding the patient's future fertility potential. To integrate this treatment method optimally into patient care, knowledge is needed about the clinical indications for therapeutic embolization, the relevant vascular anatomy, technical considerations of the procedure, and the potential risks and benefits of embolization. The most well-known and well-studied transcatheter embolization technique for treating a gynecologic-obstetric condition is uterine fibroid embolization. However, the clinical indications for transcatheter embolization are much broader and include many benign gynecologic conditions, such as adenomyosis and arteriovenous malformations, as well as intractable bleeding due to inoperable advanced-stage malignancies. Uterine artery embolization may be performed to prevent or treat bleeding associated with various obstetric conditions, including postpartum hemorrhage, placental implantation abnormality, and ectopic pregnancy. Embolization of the uterine artery or the internal iliac artery also may be performed to control pelvic bleeding due to coagulopathy or iatrogenic injury, and ovarian vein embolization has been shown to be effective for the management of pelvic congestion syndrome. The article discusses these and other gynecologic and obstetric indications for transcatheter embolization, provides detailed descriptions of imaging findings before and after embolization, and reviews procedural techniques and outcomes.

Current concepts in uterine fibroid embolization

Uterine fibroid embolization (UFE) has become established as an accepted minimally invasive treatment for uterine fibroids and should be considered a treatment option for patients with symptomatic uterine fibroids. It is important for diagnostic radiologists to understand the procedure, since imaging is a key component in the evaluation and care of these patients. Both the interventional radiologist and the gynecologist must fully evaluate a patient before recommending UFE as a treatment for symptomatic fibroids. However, relatively few absolute contraindications exist (pregnancy, known or suspected gynecologic malignancy, and current uterine or adnexal infection). A thorough evaluation includes a medical history, menstrual history, physical examination, and discussion of fertility goals. In almost all cases, bilateral uterine artery catheterization and embolization are needed, since most uterine fibroids, whether single or multiple, receive blood supply from both uterine arteries. After UFE, patients can reasonably expect resolution of symptoms such as menorrhagia, pelvic pressure, and pelvic pain. Although infrequent, major adverse events can occur and include ovarian failure or amenorrhea, fibroid expulsion, and rarely venous thromboembolism. Hysterectomy remains the definitive and most common treatment for uterine fibroids, but less-invasive approaches such as UFE are becoming of greater interest to both patients and physicians.