What is the role of MRI in the diagnosis of malignant ovarian tumors?

Updated: Feb 27, 2019
  • Author: Arthur C Fleischer, MD; Chief Editor: Eugene C Lin, MD  more...
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Answer

The primary advantage of using MRI in the evaluation of ovarian masses is the ability to employ this modality in the characterization of tissue. The presence of fat, hemorrhage, mucin, fluid, and solid tissue within an ovarian mass can be determined with the aid of MRI. The ability to characterize tissue in this way is most useful in determining whether a mass is definitely benign. [1, 9]

To determine the potential of malignancy for epithelial tumors, assessing the internal architecture is useful. In this situation, for example, gadolinium enhancement can be employed in the differentiation of solid papillary tissue (which can enhance) from clot or debris (which does not). Gadolinium enhancement is useful in the evaluation of the internal architecture of predominantly cystic lesions. In addition, if the mass is malignant, gadolinium enhancement may aid in the depiction of peritoneal implants.

Obtain images in at least 2 planes with T1- and T2-weighted sequences. [1]

For masses with high signal intensity on T1-weighted images, the addition of fat-saturated, T1-weighted images is useful in differentiating fat from hemorrhage. [1]  If the signal intensity of a lesion is high on the T1-weighted image, the lesion can contain fat, hemorrhage, or mucin. If the lesion loses signal intensity after fat saturation, it contains fat; most likely, it is a cystic teratoma. If it does not lose signal, the lesion most likely contains hemorrhage, and it may represent an endometrioma or hemorrhagic cyst. Endometriomas are often dark on T2-weighted images. [21] In addition, high-viscosity mucin can be bright on T1-weighted images. Low-viscosity mucin is dark on T1-weighted images. [22]

If a lesion is dark on T1- and T2-weighted images, it may contain fibrotic tissue and be a fibroma. Consider a fibrothecoma or Brenner tumor.

Gadolinium-based contrast agents have been linked to the development of nephrogenic systemic fibrosis (NSF) or nephrogenic fibrosing dermopathy (NFD). The disease has occurred in patients with moderate to end-stage renal disease after being given a gadolinium-based contrast agent to enhance MRI or magnetic resonance angiography (MRA) scans. NSF/NFD is a debilitating and sometimes fatal disease. Characteristics include red or dark patches on the skin; burning, itching, swelling, hardening, and tightening of the skin; yellow spots on the whites of the eyes; joint stiffness with trouble moving or straightening the arms, hands, legs, or feet; pain deep in the hip bones or ribs; and muscle weakness.

In a multivariate analysis, the accuracy of gadolinium-enhanced MRI in the diagnosis of ovarian malignancy was 93%. [23] The findings most predictive of malignancy were necrosis in a solid lesion (odds ratio, 107) and vegetations in a cystic lesion (odds ratio, 40). In addition, ancillary findings, such as ascites, peritoneal metastases, and hemorrhage, on MRI scans had a high predictive value for malignancy. The use of gadolinium-based contrast agents improves tissue characterization and increases the degree of confidence for MRI findings.

As with CT scans, MRI scans may depict numerous benign processes, such as complex functional cysts, tubo-ovarian abscesses, and benign tumors, that can mimic an ovarian malignancy.


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