Développements récents en imagerie ultrasonore de contraste à visée oncologique

Preoperative diagnosis of ovarian tumors using pelvic contrast-enhanced sonography

OBJECTIVE

The purpose of this study was to assess the feasibility of using a contrast agent for the sonographic examination of adnexal tumors and identify discriminating parameters in the preoperative diagnosis of malignant tumors.

METHODS

We conducted a prospective descriptive monocenter study that analyzed validated echographic criteria and parameters of the enhancement curve obtained by sonographic contrast agent injection. Patients included were referred for a second opinion after the discovery of a suspicious ovarian image. The final diagnosis was reached after surgery and an anatomopathologic examination.

RESULTS

Fifty-two tumors were analyzed. Morphologic and Doppler criteria analyses were conducted as described in the literature. The significant parameters of the enhancement curve were the time-intensity curve total area and the duration of activity of the contrast agent during the first phase of decay (P < .002). The performance of the contrast agent was lower than that of the examiner's subjective diagnosis, with an area under the receiver operating characteristic curve (AUC) of 0.78 versus 0.80. When borderline tumors were eliminated, there was an inversion of this, with an AUC of 0.85 versus 0.73. The inclusion of contrast results in the examiner's diagnosis in the context of a bivariate model comparing malignant and borderline tumors with benign tumors provided an AUC of 0.88.

CONCLUSIONS

Contrast-enhanced sonography improves preoperative diagnosis of ovarian tumors parameters. The significant parameters of the enhancement curve were significantly different for malignant and benign tumors. Borderline tumors contribute to a reduction of the discriminating capacity of the contrast agent.

[Role of contrast enhanced US in the evaluation of renal tumors]

PURPOSE

To evaluate the role of contrast enhanced US in the characterization of renal tumors. Materials and methods. Eighty-six renal tumors (33 solid, 53 cystic) underwent contrast enhanced US after indeterminate CT/MRI (67 lesions) or US (19 lesions). Pathological correlation was available for 42 cases, and follow-up at 3 and 6 months was available for 13 cases. Diagnosis was achieved in 21 cases. Lesions included: 19 renal cell carcinomas (4 conventional, 14 papillary, 1 tubulocystic), 5 oncocytomas, 3 metastases, 6 pseudomasses, and 53 cystic lesions including 6 malignant tumors.

RESULTS

Solid tumors were correctly identified in 100% of cases. Characterization of solid tumors was possible with specificity of 92.9% for papillary carcinoma, 57.1% for clear cell carcinoma, and 100% for oncocytoma. The specificity for distinguishing solid benign from solid malignant tumor was 100% based on the presence of hypoechogenicity relative to normal renal parenchyma on delayed imaging. Contrast enhanced US allowed reclassification of 23 indeterminate lesions on conventional US. It is of limited value for large cystic lesions or cystic lesions with extensive wall calcification.

CONCLUSION

Contrast enhanced US is easily performed in clinical practice and allows improved characterization of some renal tumors compared to other cross sectional imaging techniques.

[Evaluation of early response to antiangiogenic treatment with dynamic contrast enhanced ultrasound]

Early functional imaging evaluation of targeted treatments in oncology is of major importance. Dynamic contrast enhanced US is now recognized as a functional imaging technique able to evaluate new antiangiogenic drugs targeting superficial and deep seated lesions. This evaluation is based on an analysis of the curve of signal intensity over time after injection of the contrast agent. The availability of quantification software allows objective quantification of tumor perfusion parameters from linear raw data, prior to logarithmic signal compression, including maximum intensity of enhancement, mean transit time, time to peak, and wash-in slope coefficient. Dynamic contrast enhanced US, a sensitive, reproducible and readily available technique, allows early prediction of tumor response to treatment based on changes in vascularity, before morphological changes (RECIST) become apparent.