It's no surprise that physicians rely upon many techniques to screen for, diagnose, and treat breast cancer. The imperfect nature of physical exams and imaging studies often requires multiple procedures to be performed on a patient to properly evaluate disease presence, with the objective that better diagnostic performance through a combination of techniques will improved outcomes and reduce unnecessary procedures. Mammography, ultrasound, and MRI are the imaging modalities most commonly used at various points in the breast cancer pathway. The combination of these modalities serves to ensure patients are receiving the most appropriate treatment.
However, even together, these anatomical imaging studies have limitations with respect to both the type and quality of the information obtained. These clinical and operational limitations have and continue to lead to the development of "next-generation" breast imaging modalities, such as 3D tomosynthesis, breast-specific gamma imaging (BSGI), and positron emission mammography (PEM). Despite their limited adoption to date (or no adoption in the U.S. for tomosynthesis as an investigational technology), considerable promise exists for these modalities as they add new anatomical and functional dimensions to standard imaging modalities.
But what happens when you combine these cutting-edge technologies that have, to some extent, demonstrated improvements over much-accepted technologies? Is the end result a "super" modality with synergistic effects, or simply another widget to aid in breast cancer evaluation? Researchers are exploring these very questions, with a hybrid tomosythesis-molecular breast imaging system emerging as a futuristic modality to keep track of in the years to come.
Reported in trade website AuntMinnie.com and published in the April issue of the journal Radiology, researchers from the University of Virginia in collaboration with medical device developers are experimenting with a hybrid tomosynthesis-molecular breast imaging (MBI) device to test its ability to detect cancer earlier in patients with dense breasts. In combining the two modalities, researchers hypothesized the dual-modality system - which uses 3D tomosynthesis and 3D MBI - would improve upon the existing limitations of other breast imaging studies, such as mammography and ultrasound.
With a small sample of 17 women with 21 lesions, the hybrid dual-modality tomosynthesis (or DMT) system demonstrated strong diagnostic performance, with sensitvity, specificity, positive predictive value, negative predictive value, and accuracy of 86%, 100%, 100%, 93%, and 95%, respectively. Compared to tomosynthesis alone, the hybrid DMT system yielded much higher diagnostic performance, though the results of the hybrid DMT system were similar to the MBI teqhnique alone. While the investigators note the similarities between they hybrid system and MBI alone, the results could be attributable to the small sample size and small number of lesions in the study group.
Taken together, much research is still needed to better define the roles of molecular breast imaging and tomosynthesis, let alone as a hybrid modality. As we anticipate commercial availability of a tomosynthesis system in the future, more experimental technologies such as these will come to fruition, and the greater interest in technology hybridization (PET/CT, SPECT/CT, PET/MR, fusion ultrasound) will likely yield new, never-before-seen experiences breast cancer imaging. But should providers be planning for or least consider these technologies now?
Tomosynthesis: Yes, due to its promising potential and disruptive effect
Molecular Breast Imaging: Possibly, but it's more of a niche technology right now
Hybrid Tomosynthesis-MBI: Not likely any time soon!