Study: MRI technique detects invasion of jawbone by oral cancer
The MRI technique called SWIFT (Sweep Imaging with Fourier Transformation) appears feasible to help provide a 3D assessment that may aid in detecting invasion of the mandible by oral cancer, according to a study in the September issue of Archives of Otolaryngology—Head and Neck Surgery, one of the JAMA/Archives journals.
Ayse Tuba Karagulle Kendi, MD, and colleagues from the University of Minnesota, Minneapolis, wrote that advanced squamous cell carcinoma that arises in the oral cavity frequently invades the mandible. Depending on the degree of invasion, segmental removal of the mandible may be required for treatment.
“Unfortunately, detecting bone invasion prior to surgery is often difficult using currently available imaging techniques,” wrote the authors, adding that a high degree of imaging accuracy would prevent unnecessary mandible surgery while improving functional and cosmetic outcomes in the surgeries that are performed.
CT and conventional MRI have been commonly used preoperatively to assess mandibular invasion in oral carcinoma, but these techniques don’t always provide a clear and accurate assessment of tumor infiltration into the mandible. The authors wanted to determine the feasibility of the SWIFT method to identify mandibular invasion, and compared images obtained with this method to histologic sections.
Kendi and colleagues imaged two specimens from each patient using a 9.4-T MRI system. The patients had already undergone segmental mandible removal.
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, according to the study. Evidence of mandibular invasion with tumor was found in both specimens by histopathology and there was a high degree of correlation between MRI and histopathologic findings.
SWIFT uses time-shared excitation and signal acquisition to allow delineated assessment of cortical and medullary bone. Cortical bone does not produce a signal with conventional MRI techniques and there is difficulty in resolving the difference between cortical irregularity and tumor invasion using CT. Prosthetic implants and artifacts produced by dental amalgam can also compromise the accuracy of CT.
“SWIFT obtains signal from cortical bone that has a fast decaying signal, produces less distortion from magnetic susceptibility and is less sensitive to motion artifacts,” wrote the authors.
The authors noted that the study focused only on specimens from patients with preoperative clinical and radiologic evidence of bone invasion. Merely designed to test the feasibility of SWIFT, the study results did not reflect the strength of the technique in detecting early cortical bone invasion by oral cancer. Kendi et al were optimistic, however, that early-detection techniques may result from the high-quality images created by SWIFT.
Plans are underway to develop further human subject study of the SWIFT technique in the assessment of head and neck tumors, the authors noted.
Ayse Tuba Karagulle Kendi, MD, and colleagues from the University of Minnesota, Minneapolis, wrote that advanced squamous cell carcinoma that arises in the oral cavity frequently invades the mandible. Depending on the degree of invasion, segmental removal of the mandible may be required for treatment.
“Unfortunately, detecting bone invasion prior to surgery is often difficult using currently available imaging techniques,” wrote the authors, adding that a high degree of imaging accuracy would prevent unnecessary mandible surgery while improving functional and cosmetic outcomes in the surgeries that are performed.
CT and conventional MRI have been commonly used preoperatively to assess mandibular invasion in oral carcinoma, but these techniques don’t always provide a clear and accurate assessment of tumor infiltration into the mandible. The authors wanted to determine the feasibility of the SWIFT method to identify mandibular invasion, and compared images obtained with this method to histologic sections.
Kendi and colleagues imaged two specimens from each patient using a 9.4-T MRI system. The patients had already undergone segmental mandible removal.
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, according to the study. Evidence of mandibular invasion with tumor was found in both specimens by histopathology and there was a high degree of correlation between MRI and histopathologic findings.
SWIFT uses time-shared excitation and signal acquisition to allow delineated assessment of cortical and medullary bone. Cortical bone does not produce a signal with conventional MRI techniques and there is difficulty in resolving the difference between cortical irregularity and tumor invasion using CT. Prosthetic implants and artifacts produced by dental amalgam can also compromise the accuracy of CT.
“SWIFT obtains signal from cortical bone that has a fast decaying signal, produces less distortion from magnetic susceptibility and is less sensitive to motion artifacts,” wrote the authors.
The authors noted that the study focused only on specimens from patients with preoperative clinical and radiologic evidence of bone invasion. Merely designed to test the feasibility of SWIFT, the study results did not reflect the strength of the technique in detecting early cortical bone invasion by oral cancer. Kendi et al were optimistic, however, that early-detection techniques may result from the high-quality images created by SWIFT.
Plans are underway to develop further human subject study of the SWIFT technique in the assessment of head and neck tumors, the authors noted.
Evan Godt, Writer
Evan joined TriMed in 2011, writing primarily for Health Imaging. Prior to diving into medical journalism, Evan worked for the Nine Network of Public Media in St. Louis. He also has worked in public relations and education. Evan studied journalism at the University of Missouri, with an emphasis on broadcast media.