Ovarian Masses: MR Imaging with T1-weighted 3-dimensional Gradient-echo IDEAL Water-fat Separation Sequence at 3T

Abstract

Purpose: We retrospectively compared the e‹cacy of 3-dimensional (3D) gradient-echo magnetic resonance T 1 -weighted sequence using the iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) technique with the e‹cacy of conventional 3D gradient-echo sequences for diagnosing ovarian masses at 3T.Materials and Methods: In images of 32 women (mean age, 45.3 years) with ovarian masses who underwent T 1 -weighted imaging with both IDEAL and conventional techniques, we quantitatively analyzed signal-to-noise ratio (SNR) and contrast between gluteal muscle and T 1 -weighted high-signal materials within lesions and assessed image quality. Two radiologists independently evaluated fat detection.Results: Mean SNR of subcutaneous fat did not diŠer signiˆcantly between IDEAL and conventional techniques for both fat-suppressed ( P＝.32) and non-fat-suppressed ( P＝.85) images. Mean absolute contrast between gluteal muscle and T 1 -weighted high signal materials within teratomas (n＝15) was signiˆcantly higher with IDEAL on fat-suppressed images ( P＝.002) and lower with IDEAL on non-fat-suppressed images ( P＝.010). Fat suppression was signiˆcantly superior with IDEAL ( Pº.0001). Readers' assessments of fat detection did not diŠer between IDEAL and conventional sequences.Conclusion: The quality of T 1 -weighted fat-suppressed images of ovarian masses was better with 3D gradient-echo IDEAL than conventional 3D gradient-echo sequences.

Abdominal MRI at 3.0 T: LAVA‐flex compared with conventional fat suppression T1‐weighted images

“…Because the appearances of the images generated with the different sequences were obvious, the radiologists could not be blinded to the type of acquisition; however, the two radiologists were not aware of the endpoints of the study. The two readers compared the two sequences to evaluate the image quality, fat suppression quality, susceptibility artifacts, and motion artifacts . They graded the image quality using a five‐point scale on which 1 point indicated unacceptable quality, 2 points indicated poor quality, 3 points indicated fair quality, 4 points indicated good quality, and 5 points indicated excellent quality.…”

“…LAVA‐flex then reconstructs pure water and fat images in seconds by applying a two‐point Dixon method to data from in‐phase and out‐of‐phase images . Iterative decomposition of water and fat with echo asymmetry and least‐square estimation (IDEAL) is a variant of the three‐point Dixon method , which is different from LAVA‐flex. IDEAL also provides robust and uniform fat‐separation and has been used to image many body regions including the spine , musculoskeletal system , artery , and abdomen .…”

Magnetic resonance imaging findings for discriminating clear cell carcinoma and endometrioid carcinoma of the ovary

“…Ultrasonography is advantageous, compared with CT and MRI, due to its accessibility as a first-line imaging examination, which is painless and relatively inexpensive compared with CT and MRI. However, MRI offers the following potential advantages compared with the other modalities: lack of ionizing radiation exposure relative to CT, higher contrast resolution, higher specificity, greater accuracy, more reliable and reproducible measurements, and good inter-observer agreement for identification of malignant ovarian lesions [2]. The accuracies of ovarian cancer patient diagnosis with ultrasonography, CT, and MRI are 84–89%, 82–88%, and 88–93%, respectively [3–7].…”

MRI features of ovarian cystic lesions

“…Fat‐suppressed T1‐weighted imaging is necessary when a high signal intensity lesion is seen in the ovary on a T1‐weighted image, to help to differentiate between fat and blood. Recently, the values of 2‐point and 3‐point dual‐echo Dixon techniques to simultaneously obtain four types of T1‐weighted images (in‐phase, opposed‐phase, water‐only, and fat‐only images) in a single acquisition have been reported. Compared with standard fat‐suppressed T1‐weighted imaging, dual‐echo Dixon imaging facilitates improved image quality of fat‐suppressed images of the pelvis, enabling better delineation of pathologic lesions.…”