**Diagnostic Value of Dynamic Contrast-Enhanced MRI in Endometrial Cancer**

Ting Zhang, Ai-Lian Liu, Mei-Yu Sun, Ping Pan, Jin-Zi Xing and Qing-Wei Song *Radiology Department of the First Affiliated Hospital of Dalian Medical University China* 

#### **1. Introduction**

Endometrial cancer is the second most common cancer of the female reproductive organs after cervical cancer in China. The depth of myometrial invasion is the most important factor for treatment selection and prognosis prediction【1】. Magnetic resonance imaging (MRI) provides high spatial resolution and excellent soft tissue contrast. The contrast of tumors to uterine cavity and myometrium can be further improved with the use of contrast agents and the enhancement features of tumors at different stages can be analyzed quantitatively and dynamically【5】 . However, the relationship between the clinical stages and differentiation degrees of endometrial cancer and the time-intensity curve (TIC) types or the enhancement rates is still not clear on the dynamic contrast-enhanced MRI (DCE-MRI). This study aimed to explore the relationship between the quantitative data of DCE-MRI and the staging of endometrial cancer by investigating the DCE-MRI characteristics of endometrial cancer at different stages, and thus to evaluate the usefulness of the quantitative data and the TIC types of MRI in the diagnosis of endometrial cancer and identification of their degrees of differentiation.

#### **2. Methods**

#### **2.1 Cases**

A retrospective analysis of 24 patients with endometrial cancer from April 2007 to July 2009 was performed. The diagnosis was confirmed with diagnostic curettage in all patients. The 24 patients received MRI examination in our hospital and of them, 15 patients underwent MRI within 1 week after surgery. The mean age of the patients was 55.8 years, ranging from 28 to 77. Eight patients were pre-menopausal and 16 were postmenopausal. The clinical symptoms included postmenopausal vaginal bleeding in 19 cases, increased vaginal discharge in 2 cases, increased menstrual flow and extended menstrual period in 1 case, and contact bleeding in 2 cases. Informed written consent was obtained from all patients.

#### **2.2 MRI techniques**

MRI was performed using GE 1.5T Signa HD Echospeed Superconducting Scanner with body phased-array. Intrauterine device was removed from each patient who had it and all patients were asked to drink about 500 ml water to make the bladder moderate full 1 h before the scanning. Conventional MRI was first performed with the sequences of SE T1 weighted imaging (T1WI) and fat-suppressed FSE T2-weighted imaging (T2WI). DCE-MRI was then performed in 9 patients with horizontal surface fast spoiled gradient echo (FSPGR) sequence and in 15 patients with sagittal liver volume T1-weighted ultra-fast threedimensional imaging (liver acquisition with volume acceleration, LAVA). MR scanning ranged from the upper edge of the iliac wing to the level of bilateral femoral neck with patients in the supine position. For DCE-MRI, Gd-DTPA contrast agent (0.1 mmol/kg) was given to each patient through antecubital vein using a high-pressure syringe with a flow rate of 2.5 ml/s. Scanning was taken at 16, 32, 48, 64, and 300 seconds (s), respectively, after injection. The scanning parameters were summarized in Table 1.

#### **2.3 Image analysis 2.3.1 Analysis of the tumor characteristics**

#### **2.3.1.1 General types**

Two types were classified: diffuse type and focal type. Diffuse type was defined as extensive thickening of the uterine endometrium (>3 mm for menopause and >10 mm for premenopausal patients). The focal type was defined as the formation of soft-tissue mass.

#### **2.3.1.2 Invasion depth**

Two groups were divided. One group referred to the tumors with no myometrial invasion (intact junctional zone and homogeneous low signal on T2WI) or with superficial myometrial invasion (depth of the myometrial invasion, ≤1/2). Another group referred to the tumors with deep myometrial invasion (myometrial invasion, >1/2).


Note: FSPGR: fast spoiled gradient echo sequence; LAVA: liver volume three-dimensional ultra-fast T1WI sequence.

Table 1. The sequence parameters of MRI.
