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

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.

Novel interferon-gamma assays for diagnosing tuberculosis in young children in India.

SETTING: The tuberculin skin test (TST) and interferon-gamma release assays (IGRAs) are used as supportive evidence to diagnose active tuberculosis (TB). Novel IGRAs could improve diagnosis, but data are lacking in young children. DESIGN: Children (age 5 years) with suspected TB were prospectively screened at a tertiary hospital in Pune, India; the children underwent TST, and standard (early secretory antigenic target 6 and culture filtrate protein 10) and enhanced (five additional novel antigens) enzyme-linked immunospot (ELISpot) assays. RESULTS: Of 313 children (median age 30 months) enrolled, 92% had received bacille Calmette-Guérin vaccination, 53% were malnourished and 9% were coinfected with the human immunodeficiency virus (HIV); 48 (15%) had TB, 128 (41%) did not, and TB could not be ruled out in 137 (44%). The sensitivity of enhanced (45%) and standard (42%) ELISpot assays for diagnosing TB was better than that of TST (20%) (P  0.03); however, enhanced ELISpot was not more sensitive than the standard ELISpot assay (P = 0.50). The specificity of enhanced ELISpot, standard ELISpot and TST was respectively 82% (95%CI 74-89), 88% (95%CI 81-94) and 98% (95%CI 93-100). Rv3879c and Rv3615c, previously reported to be promising antigens, failed to improve the diagnostic performance of the ELISpot assay. CONCLUSION: The TST and the standard and novel ELISpot assays performed poorly in diagnosing active TB among young children in India.

Novel adjunctive therapies for the treatment of tuberculosis.

Despite significant efforts to control tuberculosis (TB), the disease remains a major global threat, with an estimated 8.6 million new cases and 1.3 million deaths in 2012 alone. Significant treatment challenges include HIV co-infection, the dramatic rise of multidrug-resistant TB and the vast reservoir of latently infected individuals, who will develop active disease years after the initial infection. The long duration of chemotherapy also remains a major barrier to effective large scale treatment of TB. Significant advances are being made in the development of shorter and effective TB drug regimens and there is growing evidence that host-directed and "non-antimicrobial" pathogen-directed therapies, could serve as novel approaches to enhance TB treatments. This review highlights the rationale for using these therapies and summarizes some of the progress in this field.

Noninvasive determination of 2-[18F]-fluoroisonicotinic acid hydrazide pharmacokinetics by positron emission tomography in Mycobacterium tuberculosis-infected mice.

Tuberculosis (TB) is a global pandemic requiring sustained therapy to facilitate curing and to prevent the emergence of drug resistance. There are few adequate tools to evaluate drug dynamics within infected tissues in vivo. In this report, we evaluated a fluorinated analog of isoniazid (INH), 2-[(18)F]fluoroisonicotinic acid hydrazide (2-[(18)F]-INH), as a probe for imaging Mycobacterium tuberculosis-infected mice by dynamic positron emission tomography (PET). We developed a tail vein catheter system to safely deliver drugs to M. tuberculosis aerosol-infected mice inside sealed biocontainment devices. Imaging was rapid and noninvasive, and it could simultaneously visualize multiple tissues. Dynamic PET imaging demonstrated that 2-[(18)F]-INH was extensively distributed and rapidly accumulated at the sites of infection, including necrotic pulmonary TB lesions. Compared to uninfected animals, M. tuberculosis-infected mice had a significantly higher PET signal within the lungs (P < 0.05) despite similar PET activity in the liver (P > 0.85), suggesting that 2-[(18)F]-INH accumulated at the site of the pulmonary infection. Furthermore, our data indicated that similar to INH, 2-[(18)F]-INH required specific activation and accumulated within the bacterium. Pathogen-specific metabolism makes positron-emitting INH analogs attractive candidates for development into imaging probes with the potential to both detect bacteria and yield pharmacokinetic data in situ. Since PET imaging is currently used clinically, this approach could be translated from preclinical studies to use in humans.

Inhibition of pathogenic enteric bacteria by hyperbaric oxygen: enhanced antibacterial activity in the absence of carbon dioxide.

The antibacterial effects of 24-h exposures to high-pressure oxygen in relation to environmental CO(2) were studied at 3 atm absolute (ata) and at 1 ata. Eight gram-negative, aerobic and facultatively aerobic, pathogenic enteric bacteria (Salmonella typhosa, Salmonella paratyphi, Salmonella schottmuelleri, Shigella dysenteriae, Shigella flexneri, Proteus vulgaris, Pseudomonas aeruginosa, and Escherichia coli) were exposed as shallow-broth cultures and agar surface cultures. Although broths supplemented with 0.2% glucose permitted some growth of Salmonella typhosa, Salmonella schottmuelleri, Shigella dysenteriae, and Shigella flexneri during exposure to high-pressure oxygen in the presence of CO(2), the other species grew only after the exposure, indicating a bacteriostatic effect. Both bacteriostatic and bactericidal effects were demonstrated on the surface of Trypticase soy agar, where killing of Salmonellea typhosa, Proteus vulgaris, and Pseudomonas aeruginosa was significantly greater after exposure to pure O(2) at 3 ata than at 1 ata. At 3 ata, significantly more killing occurred upon exposure of all species (except Shigella dysenteriae and S. flexneri) on an agar surface to 100% O(2) as compared with exposure to a mixture of 95% O(2) + 5% CO(2). Thus, deprivation of CO(2) during exposure to pure O(2) enhanced the bactericidal effect of high-pressure oxygen.