Magnetic resonance imaging (MRI) technology is an extremely important part of a doctors arsenal for looking inside the body. According to a report in the September issue of Archives of Otolaryngology-Head and Neck Surgery, one of the JAMA/Archives journals, a type of MRI technique called SWIFT (sweep imaging with Fourier transform) may help to provide a three-dimensional assessment to assist in detecting spread of oral cancer to the jawbone.

Background information in the article explains how advanced squamous cell carcinoma in the oral cavity frequently invades the mandible (jawbone). Treatment may or may not necessitate removal of the mandible.

“Unfortunately, detecting bone invasion prior to surgery is often difficult using currently available imaging techniques,” write the authors.

It is obviously very helpful to the surgeon if the degree and location of invasion can be determined before surgery. Having more accurate information prior to surgery would logically enable the surgeon to contain the cancerous cells, prevent unnecessary mandible removal and aid in planning for reconstruction.

Surgeons normally use a variety of techniques including MRI to assess tomography prior to performing any surgery, however they are not always able to gain the full picture of the degree to which and oral tumor has invaded the mandible.

The SWIFT method of MRI for mandibular invasion by squamous cell carcinoma was investigated by the authors and they conclude that the method offers a delineated assessment of cortical (compact bone which forms the outer shell of some structures) and medullary (inner cavity where marrow is stored) bone, “…which is not possible with conventional imaging techniques…”

Ayse Tuba Karagulle Kendi, M.D., and colleagues from the University of Minnesota, Minneapolis, designed a descriptive case study in which participants were patients with oral carcinoma who underwent segmental mandibulectomy at a tertiary academic institution. The researchers used a 9.4-T Varian MRI system to examine two specimens from each patient for cortical and medullary invasion by cancer cells. Histologic sections (specimens examined with a microscope) were compared with the images obtained by the SWIFT technique.

Images produced by the SWIFT technique with in vitro specimens were of sufficient resolution (156 to 273 micrometers) to accurately depict tumor invasion of cortical and medullary bone. Evidence of mandibular invasion with tumor was found in both specimens by histopathology. Researchers found a high degree of correlation between magnetic resonance images and histopathologic findings.

They conclude that:

“This preliminary report demonstrates that the SWIFT imaging technique has the capacity to show fine details of intramandibular anatomy […] Furthermore, the correlations between the histologic and MR [magnetic resonance] images of these two specimens clearly show malignant invasion that has not been previously demonstrated with MR techniques. The data described in this report suggest that MRI has a great deal of potential in accurately determining bone invasion preoperatively.”

Written by: Rupert Shepherd Bsc.