"DWI can be easily added onto the routine pelvic MRI examination, lengthening the examination by three to five minutes," lead author Dr. Michael Chew told Reuters Health. "It is noninvasive and does not involve radiation exposure or injection of contrast agents." Most importantly, "It may provide useful information regarding lymph node metastases in gynecologic malignancy that will direct patients to appropriate treatment."

The study, which involved 47 nodal specimens from 40 patients with cervical, endometrial, or ovarian cancer, compared the accuracy of DWI with concurrent PET/CT imaging or the pathology report. The Boston-based research team analyzed DWIs qualitatively, such that malignancy was indicated by hyperintensity on DWI and hypointensity on apparent diffusion coefficient measurement maps.

"Qualitative interpretation of DWI performed reasonably well -- 92% sensitivity, 85% specificity, and 87% accuracy, with a very high negative predictive value of 97% and interobserver agreement (kappa = 0.9)," Chew said.

According to Chew, the primary value of DWI in lymph node staging of gynecologic malignancies may be its high negative predictive value. "When DWI determines that a node is not involved by tumor, it is almost always correct. We were a little surprised by this result."

The research team now intends to confirm their findings in larger studies that include more patients and multiple institutions. "We also hope to refine our DWI technique, both in terms of acquisition of accurate data and interpretation of this data," the radiologist added.

By Karla Gale

Last Updated: 2009-05-04 16:55:30 -0400 (Reuters Health)

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