However, the issue of

divergent sensitivities of the two modalities remains. Frullano et al. [76] addressed this problem by producing a low-specific-activity PET–MR agent so that a sufficient concentration of the MR component could be achieved while maintaining an appropriate amount of injected radioactivity. However, given the limited sensitivity of MRI, PET–MR probes, in general, cannot be considered Selleck HIF inhibitor “tracers” in the traditional sense, which may limit the potential targets for such dual-modality agents. Beyond such examples, it is not immediately clear how many dual PET–MRI tracers present advantages over a corresponding single-modality tracer. Several of the above-referenced papers commented on the potential for improved diagnostics (in terms of increased sensitivity and specificity) and greater understanding of the underlying biology, but it is not self-evident that this should be the case. Currently, there Atezolizumab concentration is a paucity of data demonstrating the value in localizing a dual-modality tracer beyond merely the ability to detect it with both modalities (particularly, given the exquisite molecular sensitivity of

PET); that is, what new information can be learned by simultaneously detecting the agent by both modalities? As discussed in the next section, however, contrast agent “cocktails” (injections of two agents: one for PET and one for MRI) are of potential interest. It is instructive to divide the potential uses of PET–MRI in oncology into short- and long-term applications. Short-term applications include those that would require minimal new studies or validation in order to implement

PET–MRI in clinical practice. Long-term applications are those which logically stand to benefit from the spatial and temporal co-registration of PET and MRI functional measures, but for which there is currently a paucity of supporting data. Potential Abiraterone datasheet short-term applications of PET–MRI in oncology include both disease staging and clinical situations calling for detailed characterization of a particular lesion or region. For disease staging, combined PET–MRI may offer advantages over separate PET and MRI examinations for measuring the distribution of disease over the whole body, while simultaneously providing required high-spatial-resolution imaging of one particular disease site; that is, PET can provide whole-body assessment, thereby guiding selection of a limited FOV for subsequent MRI and/or MR spectroscopy measurements. Examples from current oncology practice include whole-body staging of lymphoma or melanoma with simultaneous high-spatial-resolution evaluation of known brain metastases or whole-body staging of breast cancer with simultaneous high-spatial-resolution imaging of the breast for surgical planning. In other staging situations, there may be a compelling reason to use PET–MRI over PET–CT, e.g.

Overall, 48% of the variability in sighting rates was explained by the model (R2 = 0.48, df = 55). Subarea had the greatest impact on the model (F = 11.986, df 3, 6, p > F < 0.0001). Sighting rates varied among subareas and time periods ( Fig. 6), being statistically higher in Niaqunnaq Bay in early and mid-July (F = 13.71, df = 3, 6, p > F < 0.0001). Niaqunnaq

Bay sighting rates were 3–4 times higher in all time periods than the other subareas, except for West Mackenzie Bay in late July ( Fig. 6). Within subareas, sighting rates were not statistically different between the three July time periods (F = 0.024, df = 2,6, 17-AAG p > F = 0.976), and there were no significant interactions (F = 1.671, df = 1, 6, p = 0.146). The PVC analysis revealed multiple and specific geographic locations within each subarea of the TNMPA where the beluga sightings were the most concentrated, by July time period. These focal areas of concentration (Fig. 7) were used to define seven ‘hot spots’ used by belugas in the 1970s and 1980s, within the subareas for each of the

July time periods (Table 3). The ‘hot spots’ were located in each subarea: 2 in Niaqunnaq Bay, 3 in Kittigaryuit (Kugmallit Bay), 2 in Okeevik (East Mackenzie Bay), and 1 in West Mackenzie Bay (Table 3; Fig. 1 and Fig. 7). GSK1120212 cell line In Niaqunnaq Bay, the distribution of belugas was similar in the early July and mid-July time periods, with the ‘hot spots’ in two locations: PDK4 in the central portion of the subarea (and extending 10–15 km in all directions), and also where the west channel of the Mackenzie River enters Niaqunnaq Bay. This subarea was the most attractive to belugas, including belugas with calves. The distribution of belugas in Niaqunnaq Bay was more dispersed in late July, than in early or mid-July. With lower sighting rates than Niaqunnaq Bay, but similar patterns of clustering, Kugmallit Bay had three ‘hot spot’ areas (Table 3; Fig. 7). The most prominent was located approximately 6 km directly south of Hendrickson Island, in both early and mid-July

(Fig. 7a and b). In mid-July (only), there was also a ‘hot spot’ used by belugas approximately 2 km offshore of Toker Point (Fig. 7b). By late July, the belugas were more widely distributed in Kugmallit Bay (Fig. 7c), and the location of the early July ‘hot spot’ had shifted 8 km to the northeast of its early and mid-July location. In East Mackenzie Bay, there were two ‘hot spots’ revealed by these analyses, one near Rae Island, and a second between Garry and Pelly islands (Fig. 7). In West Mackenzie Bay, there was a single ‘hot spot’ indicated, this being southwest of Garry Island, most apparent during late July (Fig. 7c), but a generally widespread distribution in this subarea in late July.