Imaging for Cancer Detection
Cancer Imaging Program investigators have a number of ongoing projects in this area, research topics such as CT colonography, the use of low-dose fast spiral CT for lung cancer screening, and investigating the relationship between mammographic breast density and breast cancer risk. Two projects supporting the latter line of research include small field of view scintimammography and a study of vibro-acoustic technology.
CT and MR Colonography
Dr. Johnson’s group has developed specialized visualization software for efficient analysis of 3D CT colonography data. They found that robust sensitivity and specificity for the detection of colorectal neoplasia can be achieved using CTC in the unprepared (no cathartics) colon. This proposal represents a revolutionary approach to full structural examination of the colorectum without the requisite cathartic preparation (a major disincentive for screening). This unique advantage holds the promise of improved patient acceptance and compliance — essential prerequisites — for successful widespread screening programs. In addition, CTC has other compelling advantages including minimal invasiveness, visualization of the entire colorectum, multi-dimensional inspection of the colon wall and assessment capability of extra-colonic tissues. Dr. Johnson’s team hopes to further optimize CTC in the prepared colon and to clinically validate CTC of the unprepared colon for the detection of colorectal neoplasia.
Dr. Johnson is also the PI of the ACRIN 6664, National CT Colonography trial, with the objective of clinically validating widespread use of the technique in a screening population for the detection of colorectal neoplasia. This trial has now been completed and enrolled 2,617 patients. Publication of these findings should occur in late 2008 (In review in JAMA).
In other related research, Dr. Fletcher is examining the use of IV contrast material in to assess recurrent colorectal cancer at CT colonography. David Hough, M.D., is Principal Investigator of a project entitled “Feasibility Study for Detection of Colonic Polyps with Magnetic Resonance Colonography, CO2 Enema and Conventional Versus Fecal-Tagged Technique.” The results will be compared to a gold standard based on colonoscopy and pathology. If 70 percent or more of polyps of greater than or equal to 1 centimeter are detected, a prospective study in a larger number of patients will be considered. Collaborators on this project include Drs. Johnson, Fidler, Glockner, Felmlee, Fletcher, and David Ahlquist, M.D.
CT Screening for Lung Cancer
Stephen Swensen, M.D., is a leader in the investigation of fast low dose CT imaging as a screening modality for patients at high risk for primary lung cancer. Conservatively, screening with CT may identify less than 25% of tumors at the stage III and IV. This study has just begun the fifth year of NIH funding with a cohort of 1520 participants. To date, the study has identified 48 lung cancers through CT screening. Numerous ancillary studies exist, including ones involving biomarkers via full sputum and blood, computer aided diagnosis analysis, cost effectiveness studies, and familial/genetic research; many conducted through inter-programmatic collaborations with the Cancer Prevention and Control and the Genetic Epidemiology and Risk Assessment Programs.
Breast Cancer Imaging
Kathy Brandt, M.D., provides breast imaging expertise to a number of internal and external investigators. She is collaborating externally on a project involving oversight of re-interpretation of thousands of mammograms to detect missed cancers. She also is part of the study team for two projects led by Celine Vachon, Ph.D., "Natural History of Breast Density and Breast Cancer Risk" and “SULT1A1 and HRT - Associated Increases in Mammographic Breast Density.” Her ongoing research includes collaborations with James Ingle, M.D., and Marilyn Morton, M.D.
Dr. Ehman has devoted considerable research and development to develop a method for evaluating breast masses with MR Elastography. Preliminary results demonstrated the feasibility of delineating breast cancer in vivo with the technique. The goal of this research is to develop a practical noninvasive MRI-based method for quantitatively evaluating the mechanical properties of breast tissues. We call this technique magnetic resonance elastography (MRE). The technology development aspects of this work are being pursued in collaboration with Drs. Felmlee, Greenleaf, Manduca and Riederer. Translational aspects of this project are pursued in collaboration with other members of the Imaging program (Drs. Brandt and Amrami) and the Women’s Cancer Program (Lynn Hartmann, M.D.).
Dr. Fatemi is developing a new imaging method called "vibro-acoustography" for in vivo breast imaging and detection of breast micro-calcifications. This imaging method is non-invasive and offers some advantages in comparison to the conventional ultrasound imaging and mammography. This technique uses ultrasound in a fundamentally new type of imaging, which evaluates the relative hardness of the tissue. Micro-calcifications, much harder than soft tissue, will appear much brighter on these images. Vibro-acoustography has already been proven successful in detecting appropriate size micro-calcifications in excised human breast tissue. Successful in vivo detection of micro-calcifications will open the way for clinical use of vibro-acoustography as a noninvasive alternative to mammography. There is the potential for this imaging technique to be useful both as a diagnostic and a screening modality. This device could be a particularly valuable tool for patients with very dense breasts where mammographic detection of early cancer is limited. The lack of ionizing radiation would be of benefit to all patients, but especially young or pregnant women. Collaborators in this project include Drs. Greenleaf, Ehman, Morton and Dana Whaley, M.D.
Dr. Whaley also collaborates with Dr. Morton on a study of the impact of computer-aided diagnosis on mammographic identification of breast cancer. They are completing a two-year study that will compare cancer detection rates and evaluate the types of cancers found with and without using CAD. In other research, Dr. Whaley is reviewing of all cases of intra-cystic papillary breast cancer seen during the last ten years, in collaboration with Carol Reynolds, M.D. He is also Principal Investigator of a research study which has provided preliminary evidence that breast arterial calcifications on mammograms can serves as an indicator or heart disease.
