Combined PET/MRI: Global Warming—Summary Report of the 6th International Workshop on PET/MRI, March 27–29, 2017, Tübingen, Germany

Abstract

The 6th annual meeting to address key issues in positron emission tomography (PET)/magnetic resonance imaging (MRI) was held again in Tübingen, Germany, from March 27 to 29, 2017. Over three days of invited plenary lectures, round table discussions and dialogue board deliberations, participants critically assessed the current state of PET/MRI, both clinically and as a research tool, and attempted to chart future directions. The meeting addressed the use of PET/MRI and workflows in oncology, neurosciences, infection, inflammation and chronic pain syndromes, as well as deeper discussions about how best to characterise the tumour microenvironment, optimise the complementary information available from PET and MRI, and how advanced data mining and bioinformatics, as well as information from liquid biomarkers (circulating tumour cells and nucleic acids) and pathology, can be integrated to give a more complete characterisation of disease phenotype. Some issues that have dominated previous meetings, such as the accuracy of MR-based attenuation correction (AC) of the PET scan, were finally put to rest as having been adequately addressed for the majority of clinical situations. Likewise, the ability to standardise PET systems for use in multicentre trials was confirmed, thus removing a perceived barrier to larger clinical imaging trials. The meeting openly questioned whether PET/MRI should, in all cases, be used as a whole-body imaging modality or whether in many circumstances it would best be employed to give an in-depth study of previously identified disease in a single organ or region. The meeting concluded that there is still much work to be done in the integration of data from different fields and in developing a common language for all stakeholders involved. In addition, the participants advocated joint training and education for individuals who engage in routine PET/MRI. It was agreed that PET/MRI can enhance our understanding of normal and disrupted biology, and we are in a position to describe the in vivo nature of disease processes, metabolism, evolution of cancer and the monitoring of response to pharmacological interventions and therapies. As such, PET/MRI is a key to advancing medicine and patient care.

Whole-Body [18F]-FDG-PET/MRI for Oncology: A Consensus Recommendation

“…Thus, artifacts are mostly easily detectable in MR-AC, indicating regions of potentially inaccurate PET quantification [45,54]. ▪ While new features for the improvement of MR-AC are constantly developed and implemented into the commercial software of available PET/MRI systems, including high-resolution Dixon AC, ultrashort echo time (UTE), zero TE (ZTE) sequences and/or bone models for bone detection in PET/MRI attenuation correction [17,34,40,41], users need to remain attentive to MR-AC related limitations and artifacts in SUV quantification. ▪ Truncation artifacts along patient arms in MR-AC may affect PET quantification.…”

Current commercial techniques for MRI‐guided attenuation correction are insufficient and will limit the wider acceptance of PET/MRI technology in the clinic

“…Despite the outlined complexity of the topic, I like to conclude with a statement from the 6 th Tübingen International Workshop on PET/MR: “There was general agreement between the participants and many clinical users that MRAC has been solved to the degree required for clinical use based on accepted image metrics.” This statement is supportive of my view: we have the tools and methods for accurate and robust clinical use of PET/MR already at hand. Given the mentioned broad variety of MRAC methods, there is, however, further need toward quality control and standardization efforts in PET/MR AC .…”

A machine learning algorithm predicts molecular subtypes in pancreatic ductal adenocarcinoma with differential response to gemcitabine-based versus FOLFIRINOX chemotherapy

“…variable amounts of mutational Kras (24) and the likelihood of ongoing transitional processes, entropy as a continuous variable can be imagined as a non-invasive "sensor" of such events that correlates with the extent of basal-like regions within a particular tumor. The testing of such hypotheses is challenging, requiring an integrated whole-tumor analysis, including high data-rich imaging, histopathology and molecular profiling(25).The rapid evolution of new therapeutic options in the treatment of PDAC requires the development of markers for a reliable pre-therapeutic patient stratification and -in light of the above-mentioned plasticity, therapy monitoring. Conroy et al demonstrated significantly improved survival rates of FOLFIRINOX over Gemcitabine monotherapy in the palliative setting…”