Precision medicine is medicine optimized to the genotypic and phenotypic characteristics of an individual and, when present, his or her disease. It has a host of targets, including genes and their transcripts, proteins, and metabolites. Studying precision medicine involves a systems biology approach that integrates mathematical modeling and biology genomics, transcriptomics, proteomics, and metabolomics. Moreover, precision medicine must consider not only the relatively static genetic codes of individuals, but also the dynamic and heterogeneous genetic codes of cancers. Thus, precision medicine relies not only on discovering identifiable targets for treatment and surveillance modification, but also on reliable, noninvasive methods of identifying changes in these targets over time. Imaging via radiomics and radiogenomics is poised for a central role. Radiomics, which extracts large volumes of quantitative data from digital images and amalgamates these together with clinical and patient data into searchable shared databases, potentiates radiogenomics, which is the combination of genetic and radiomic data. Radiogenomics may provide voxel-by-voxel genetic information for a complete, heterogeneous tumor or, in the setting of metastatic disease, set of tumors and thereby guide tailored therapy. Radiogenomics may also quantify lesion characteristics, to better differentiate between benign and malignant entities, and patient characteristics, to better stratify patients according to risk for disease, thereby allowing for more precise imaging and screening. This report provides an overview of precision medicine and discusses radiogenomics specifically in breast cancer. RSNA, 2018.
The successful integration of a four-channel RF breast coil with a defined table position together with the CT-based μ-maps provides a technical basis for future clinical PET/MR breast imaging applications.
Purpose
To compare fluorine 18 (18F) fluorodeoxyglucose (FDG) combined positron emission tomography (PET) and magnetic resonance (MR) imaging with 18F FDG combined PET and computed tomography (CT) in terms of organ-specific metastatic lesion detection and radiation dose in patients with breast cancer.
Materials and Methods
From July 2012 to October 2013, this institutional review board–approved HIPAA-compliant prospective study included 51 patients with breast cancer (50 women; mean age, 56 years; range, 32–76 years; one man; aged 70 years) who completed PET/MR imaging with diffusion-weighted and contrast material–enhanced sequences after unenhanced PET/CT. Written informed consent for study participation was obtained. Two independent readers for each modality recorded site and number of lesions. Imaging and clinical follow-up, with consensus in two cases, served as the reference standard.
Results
There were 242 distant metastatic lesions in 30 patients, 18 breast cancers in 17 patients, and 19 positive axillary nodes in eight patients. On a per-patient basis, PET/MR imaging with diffusion-weighted and contrast-enhanced sequences depicted distant (30 of 30 [100%] for readers 1 and 2) and axillary (eight of eight [100%] for reader 1, seven of eight [88%] for reader 2) metastatic disease at rates similar to those of unenhanced PET/CT (distant metastatic disease: 28 of 29 [96%] for readers 3 and 4, P = .50; axillary metastatic disease: seven of eight [88%] for readers 3 and 4, P > .99) and outperformed PET/CT in the detection of breast cancer (17 of 17 [100%] for readers 1 and 2 vs 11 of 17 [65%] for reader 3 and 10 of 17 [59%] for reader 4; P < .001). PET/MR imaging showed increased sensitivity for liver (40 of 40 [100%] for reader 1 and 32 of 40 [80%] for reader 2 vs 30 of 40 [75%] for reader 3 and 28 of 40 [70%] for reader 4; P < .001) and bone (105 of 107 [98%] for reader 1 and 102 of 107 [95%] for reader 2 vs 106 of 107 [99%] for reader 3 and 93 of 107 [87%] for reader 4; P = .012) metastases and revealed brain metastases in five of 51 (10%) patients. PET/CT trended toward increased sensitivity for lung metastases (20 of 23 [87%] for reader 1 and 17 of 23 [74%] for reader 2 vs 23 of 23 [100%] for reader 3 and 22 of 23 [96%] for reader 4; P = .065). Dose reduction averaged 50% (P < .001).
Conclusion
In patients with breast cancer, PET/MR imaging may yield better sensitivity for liver and possibly bone metastases but not for pulmonary metastases, as compared with that attained with PET/CT, at about half the radiation dose.
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