Cystic teratoma of the ovary: CT detection

Adhesion formation from release of dermoid contents in the peritoneal cavity and effect of copious lavage: a prospective, randomized, blinded, controlled study in a rabbit model

OBJECTIVES

To determine, in a rabbit model, whether peritoneal exposure to dermoid cyst material produces inflammation and adhesions above control levels and whether saline lavage reduces the degree of peritoneal reaction.

DESIGN

A prospective, randomized, blinded, controlled study of adhesion formation. Thirty New Zealand white female rabbits were assigned randomly to five experimental groups: [1] laparoscopy with intraperitoneal injection of human dermoid material, [2] laparoscopy with intraperitoneal injection of human dermoid material and subsequent lavage to clear all visible dermoid material, [3] laparoscopy with saline lavage, [4] laparoscopy with intraperitoneal injection of human follicular fluid (antigenic control), and [5] laparoscopy alone.

MAIN OUTCOME MEASURES

Six weeks after initial laparoscopy, inflammation and adhesions were scored in several categories via visual assessment (range 0 to 15) and histologic microscopic evaluation (range 0 to 24). Data were evaluated using Kruskal-Wallis and Mann-Whitney U nonparametric tests.

RESULTS

For groups 1, 2, 3, 4, and 5, respectively, mean +/- SEM total inflammation-adhesion scores were 13.85 +/- 0.55, 2.90 +/- 1.15, 0 +/- 0, 1.50 +/- 1.00, and 0 +/- 0 for clinical evaluation and 16.83 +/- 1.22, 7.33 +/- 1.76, 0 +/- 0,0 +/- 0, and 0 +/- 0 for histologic evaluation. Using nonparametric tests, significant differences were found between groups in clinical and histologic scores.

CONCLUSIONS

Dermoid material produces a significant peritonitis. Results of the clinical evaluation demonstrate that saline lavage brings inflammation and adhesion formation close to control levels. However, results of the histologic evaluation suggest that the decrement in inflammation as a result of lavage may be less dramatic than that found by clinical evaluation.

Mature cystic teratomas of the ovary: CT and MR findings

OBJECTIVE

To correlate CT and MR patterns of ovarian mature cystic teratomas (MCT).

SUBJECTS AND METHODS

CT and MR findings in 25 histologically proven ovarian MCT were retrospectively reviewed. MCT characterization at CT and MR was based on detection of fat and/or a Rokitansky protuberance. MR signal intensity and CT density numbers of fat were correlated.

RESULTS

At pathology, 24/25 tumors contained fat, 1/25 a water content, and 23/25 a Rokitansky protuberance. Twenty one MCT contained fat with a density number less than-20 HU (mean density: -95 HU) and a signal intensity superior or equal to sub-cutaneous fat on T1 images, however, only six of these had a signal intensity equal to sub-cutaneous fat on T1 and T2 images and 12 had a reversed chemical shift artifact. Three contained fat with a density number ranging from -13 to +8 HU and a signal intensity inferior to subcutaneous fat on T1 images. CT showed a Rokitansky protuberance in 21/23, containing adipose tissue in 16 and calcified structures in 21. Standard MR showed a Rokitansky protuberance in 14/23 and characterized adipose tissue in eight cases, and calcified material in six cases. Finally, CT characterized 24/25 (96%) MCT. Standard MR characterized 22/25 (88%) MCT, and standard MR with fat-suppression sequences characterized 23/25 (92%) MCT.

CONCLUSION

Standard MR is less effective than CT in characterizing fat and has the same difficulty as CT in characterizing fat mixed with hair when its density is high. When fat cannot be identified by either technique, diagnosis of a Rokitansky protuberance is more easily made at CT than at MR.

Solid mature teratoma of the ovary: appearances at MR imaging

Magnetic resonance imaging (MRI) appearances of a case with rare solid mature teratoma of the ovary is presented. The lesion was almost entirely solid with small cystic component. The solid tissue, consisting of bronchial cartilage, smooth muscle, glands, and epithelium, exhibited hypointense signal on T1-weighted image, relatively hyperintense signal on T2-weighted image, and reticular pattern of enhancement on the postcontrast scan. The presence of fatty tissue mixed with hair bundle, which did not exhibit a signal intensity of fatty tissue, was clearly indicated by chemical shift artifact within the cystic component.

Ovarian cystic teratomas: value of chemical fat saturation magnetic resonance imaging

Chemical fat saturation (FS) magnetic resonance imaging (MRI) for the characterization of ovarian cystic teratoma was evaluated in 19 patients with 22 lesions. The tumour was evaluated for signal intensity, location and size; the presence of chemical shift artefact, debris and fat-fluid level. Ovarian cystic teratoma was diagnosed prospectively if the mass contained fat and/or more than one type of internal pattern on (1) SE T1-, T2-, (2) SE T1-, T2-, FS T1-weighted images. A correct diagnosis was reached in 17 of 22 tumours on conventional T1- and T2-weighted images, and in 21 of 22 tumours when fat-saturation images were added. When fat-saturation images were added, four of five tumours misdiagnosed on conventional images were then correctly diagnosed. These tumours contained only small amounts of fat. Fat-saturation images could detect smaller amounts of fat than conventional images. However, one tumour did not show decreased intensity on fat saturation images, and was not diagnosed even when fat-saturation images were added. Fat saturation images have been shown to be of value in diagnosing cystic teratomas.

Fat suppression techniques in MR imaging of mature ovarian teratomas: comparison with CT

OBJECTIVE

The aim of this study is to analyze the ability of MR fat suppression techniques to characterize fat components of ovarian mature cystic teratomas (MCT) shown by CT.

SUBJECTS AND METHODS

MR images of eight MCTs of the ovary were obtained using standard sequences followed by a SPIR (spectral presaturation with inversion recovery) sequence in six cases and by Dixon sequences in two cases. In all cases correlation with CT and pathologic findings was achieved.

RESULTS

MR fat suppression sequences showed to be as accurate as CT in detecting fat inside the cystic part of the teratomas (8/8).

CONCLUSION

MR fat suppression sequences should be performed when presence of fat is suspected on images of ovarian tumors produced by standard MR sequences.

Primary ovarian tumors in the pediatric patient: CT evaluation

Primary ovarian tumors in the pediatric age group are rare with limited descriptions on computed tomography (CT). We describe the CT findings in a series of nine mature cystic teratomas, one immature teratoma, two granulosa cell tumors, and one undifferentiated small cell tumor. Four mature cystic teratomas were atypical in their CT appearance. The immature teratoma was distinguished by its large, irregular, diffusely calcified solid component. The malignant tumors were large and nearly totally solid, or if multicystic, contained a large solid component.

Magnetic resonance imaging of female pelvic masses and local recurrent tumors at an ultra low (0.02 T) magnetic field: correlation with computed tomography

Pelvic MR (41 patients) and CT (36 patients) examinations were performed on 14 females with a primary pelvic complaint, and on 28 females with a suspicion of local recurrent disease of gynecologic malignant tumor. Benign cystic tumors were found in eight patients, five patients had endometriomas, one had a lymphoma, and one had a small androblastoma. Ten local recurrent tumors were confirmed histopathologically or cytologically. All cysts, one endometrioma, the lymphoma, and six recurrent tumors were detected on images obtained by our ultra low field magnetic unit. The smallest cyst detected was 16 mm in diameter. Small scattered implants of endometriosis were not discerned. The appearance of the tumors did not differ essentially from those described at high magnetic fields. Physical examination detected all 10 recurrent tumors, CT detected 8 of them, and MRI 6 out of 9 cases. The sensitivities of physical examination, CT and MRI to find recurrent diseases were 100%, 80%, and 67%, respectively. Corresponding specificities were 93%, 67%, and 80%. The results indicate that physical examination is most important in recurrent diseases. CT is the basic method for imaging malignant pelvic tumors. MR imaging at 0.02 T magnetic field provides a convenient and inexpensive method for more specific information, if CT findings are equivocal. MRI at 0.02 T is also accurate in detecting benign pelvic masses, but the findings are not very specific.

Diagnostic imaging of gynecological diseases: the clinician's view

The introduction of ultrasonography, computerized tomography, and magnetic resonance imaging has led to tremendous progress in the diagnostic evaluation of gynecologic diseases. Refinements in these techniques have allowed the gynecologist to diagnose unsuspected pathology, define disease and its extent, and select the most appropriate treatment despite limitations in specificity experience and cost. Practically the most appropriate imaging modalities are: ultrasonography for adnexal masses, computerized tomography for advanced cervical cancers, and magnetic resonance imaging for corpus cancers and selected cervical cancers.