Diffusion weighted MR can accurately identify benign from malignant
pelvic lymph nodes in patients with gynecologic malignancy, according
to a study performed at Massachusetts General Hospital in Boston, MA.
Diffusion weighted imaging is a noninvasive test that uses an MRI
sequence sensitized to the motion of water molecules within tissue.
“Conventional imaging with CT or MRI uses the size of a lymph node to
determine whether it is malignant. Unfortunately, lymph node assessment
by size criteria and morphology is not very accurate in detecting
metastasis,” said Michael Chew, MD, lead author of the study. This
study included pelvic MRI and DWI results of 40 patients with
gynecological malignancy. “Our study suggests that DWI can predict
lymph node involvement by a tumor with a sensitivity of 92%,
specificity of 85% and accuracy of 87%. It has a negative predictive
value of 97%, so when DWI determines that a node is not involved by a
tumor, it is almost always correct,” he said.
“The choice of correct treatment for patients with gynecological
malignancy is often determined by whether the cancer has spread to the
nodes. DWI can help to depict gynecologic malignancy more clearly and
provide useful information regarding lymph node metastasis so that
patients are directed to the appropriate treatment,” said Dr. Chew.
“It is noninvasive, safe and does not involve radiation exposure or the
injection of contrast agents. It is a simple method for defining both
primary neoplasm and lymph node spread, helping the oncologist decide
between surgery and chemoradiation, or to define the extent of surgery
that needs to be performed. It also aids in assessing prognosis,” he
“Our results are based on a small series of patients at a single
institution. The next step is to carry out larger studies that include
more patients and institutions. The long-term goal is to improve the
care of cancer patients by developing more accurate imaging,” said Dr.
— News release courtesy of The American
Roentgen Ray Society (ARRS)