Radbook2012

MammographyRAD·BOOK 201268 IT-SOLUTIONS52 RAD·BOOK 2012 * Skaane P, Gullien R, Eben EB, et. al. Reading time of FFDM and tomosynthesis in a population-based screening program. Radiological Society of North America annual meeting. Chicago, Il, 2011. ** ftp://medical.nema.org/medical/dicom/final/sup125_ft.pdf *** http://www.accessdata.fda.gov/cdrh_docs/pdf8/P080003b.pdf Radiologist Training Proper training on the interpretation of tomosynthesis images is of critical im- portance, as was demonstrated in Hol- ogic’s reader studies. To ensure access to appropriate training, Hologic has set up training classes around the world, taught by radiologists experienced in tomosyn- thesis. These classes cover the appear- ance in tomosynthesis of different den- sity parenchymal patterns, along with benign and malignant lesions. Actual clinical cases are included in the train- ing files, and self-assessment practice cases are reviewed and discussed to give radiologists an opportunity to test their learning. The following is a link to Ho- logic’s tomosynthesis training page for radiologists: www.hologic.com/radtomo Tomosynthesis Reading Time Reading a tomosynthesis study involves the evaluation of significantly more im- ages than a 2D mammography exam, as readers view each slice from a tomosyn- thesis data set containing an average of 50 or more slices. Typical slice thickness- es range from 0.5 to 1.0 mm, with more slices to review as the slice thickness is made thinner. Recent studies conclude that reading times for tomosynthesis are not unreasonable for a screening envi- ronment. The increase in the number of images reflects the increase in the infor- mation available to the radiologist, and the increased reading time is justified by the superior clinical performance.* Archiving and Display Tomosynthesis display and storage is covered by a DICOM standard.** None- theless, at this time not all PACS vendors support either the storage or display of these images. Hologic has developed, as an interim solution, a storage method whereby the tomosynthesis images are stored in a secondary capture format, which allows the storage in PACS, but for display one must use a Hologic Se- curView diagnostic workstation. It is expected that PACS companies will rap- idly implement and support the viewing of tomosynthesis images, now that the systems are in widespread use in Europe and the U.S. In planning a site, careful consid- eration must be given to the size of the images. The images from a tomosynthe- sis study can be 5 times larger than the corresponding size of a 2D digital mam- mography dataset. Network speeds and PACS storage must be adequate for the increased data flow. These larger data- sets are a natural result of tomosynthesis offering more information than digital mammograms. Conclusions Tomosynthesis is an exciting new tech- nology that offers the potential for im- provements in both screening and diag- nostic evaluations. The improvements in clinical performance, compared to 2D mammography, are significant. Hologic’s clinical study results demonstrate that 2D mammography plus Tomo can offer either improved cancer detection rate, or reduced recall rate, or both, compared to 2D alone. These are certainly very posi- tive results, and are much stronger than the ACRIN DMIST study results which compared the performance of digital to screen-film mammography, and found no average difference in performance between the two technologies.*** There is a growing body of evidence that tomosynthesis has the potential to reduce the number of exposures needed for diagnostic imaging and provide other diagnostic benefits including enhanced performance in assessing tumor size and stage and more clearly demonstrating margins and extent of lesions. Future advances in tomosynthesis include CAD algorithms to facilitate the rapid identification of suspicious clus- ters of calcifications, development of a synthesized 2D image to reduce the num- ber of exposures in an exam while still providing a 2D-equivalent image for ease of review, and contrast enhanced imag- ing for patients where access to breast MRI is limited or contraindicated. Certain implementation issues should be considered when adopting tomosynthesis, particularly in environ- ments that will include a mix of 2D and tomosynthesis-capable systems. Careful planning will help to ensure a successful transition to tomosynthesis. www.hologic.com An image reconstruc- tion algorithm cre- ates synthesized 2D images from tomo- synthesis datasets, eliminating the need for 2D screening exposures, thereby reducing both com- pression time and dose.