Role of Positron Emission Tomography in Imaging of Non-neurologic Disorders of the Head, Neck, and Teeth in Veterinary Medicine.

Positron Emission Tomography (PET) is an imaging technique that provides functional information, in addition to structural information obtained with computed tomography (CT). The most common application is cancer staging, using 18F-Fluorodeoxyglucose (18F-FDG), a radioactive analog of glucose. Although limited data are available in the veterinary literature, human studies have demonstrated benefit with the addition of PET both for assessment of the primary tumor and for detection of metastatic disease. 18F-FDG PET appears to be more accurate at detecting the margin of oral neoplasia, in particular for tumors arising from highly vascularized tissue, such as the lingual and laryngeal areas. 18F-FDG PET has a high sensitivity for the detection of lymph node metastasis, however the specificity is variable between studies. Tracers beyond 18F-FDG can also be used for oncology imaging. 18F-Fluoride (18F-NaF) is an excellent osseous tracer, useful in assessing bone involvement of primary tumors or osseous metastasis. Other specific tracers can be used to assess cell proliferation or hypoxia for tumor characterization. 18F-FDG is also an excellent tracer for detection of inflammation. Human studies have demonstrated its value for the assessment of periodontitis and dental implant infection. 18F-NaF has been used to assess disorders of the temporomandibular joint in the human literature, demonstrating good correlation with arthralgia and therapeutic outcome. Both 18F-NaF and 18F-FDG had good concordance with localization of cervical pain in people. PET will likely have a growing role in veterinary medicine not only for oncologic imaging but also for assessment of inflammation and pain

Defining characteristics of nodal disease on PET/CT scans in patients with HIV-positive and -negative locally advanced cervical cancer in South Africa

Literature reports increased FDG nodal uptake in HIV-positive patients. Our aim is to identify differences in presentation and characteristics of FDG-avid lymph nodes between HIV-positive and HIV-negative locally advanced cervical cancer (LACC) patients in our clinical setting. We evaluated 250 pre-treatment F-18-FDG PET/CT imaging studies from women screened for a phase III randomised controlled trial investigating modulated electro-hyperthermia as a radiosensitiser (Ethics approval: M120477). The number of nodes; size; maximum standardised uptake value (SUVmax); symmetry; and relationship between nodal size and SUVmax uptake, were assessed by region and by HIV status. In total, 1314 nodes with a SUVmax >= 2.5 were visualised. Of 128(51%) HIV-positive participants, 82% were on antiretroviral therapy (ART) and 10 had a CD4 count four nodes visualised in the neck, symmetrical inguinal lymph nodes, increased rates of supraclavicular node visualisation; FDG-avid axillary nodes were more common, but not exclusive, in HIV-positive participants. F-18-FDG PET/CT is a reliable staging method for LACC in HIV-positive patients who are not in acute stages of HIV infection, have a CD4 count >200 cells/mL, and/or are on ART and there is a potential risk of underestimating metastatic spread by attributing increased nodal metabolic activity to HIV infection in these patients

The value of 18F-FDG-PET/CT imaging for sinonasal malignant melanoma

The aim this study was to evaluate imaging findings using position emission tomography (PET) in combination with computed tomography (CT) and 18F-fluorodeoxyglucose (18F-FDG) in sinonasal malignant melanoma (SNMM) of the head and neck in a retrospective analysis of a consecutive cohort of patients. 18F-FDG-PET/CT examinations were performed for initial staging and compared with CT or magnetic resonance tomography (MRI), and 18F-FDG-PET alone. Medical records were reviewed retrospectively with regard to the location and the size of the tumor. Furthermore, locoregional and distant metastases with a consecutive change in therapy detected by 18F-FDG-PET/CT were assessed. Ten patients suffering from sinonasal malignant melanoma were staged and followed by 18F-FDG-PET/CT imaging. A total of 34 examinations were obtained. 18F-FDG-PET/CT depicted all primary tumors adequately. Aside from one cerebral metastasis all regional and distant metastases were truly identified by using this method. In summary, if available, 18F-FDG-PET/CT is a valuable imaging modality for staging and re-staging sinonasal malignant melanoma to evaluate expansion of the primary tumor, locoregional disease, and distant metastase

Potentiation of the abscopal effect by modulated electro-hyperthermia in locally advanced cervical cancer patients

Background: A Phase III randomized controlled trial investigating the addition of modulated electro-hyperthermia (mEHT) to chemoradiotherapy for locally advanced cervical cancer patients is being conducted in South Africa (Human Research Ethics Committee approval: M1704133; ID: NCT03332069). Two hundred and ten participants were randomized and 202 participants were eligible for six month local disease control evaluation. Screening F-18-FDG PET/CT scans were conducted and repeated at six months post-treatment. Significant improvement in local control was reported in the mEHT group and complete metabolic resolution (CMR) of extra-pelvic disease was noted in some participants. We report on an analysis of the participants with CMR of disease inside and outside the radiation field. Method: Participants were included in this analysis if nodes outside the treatment field (FDG-uptake SUV>2.5) were visualized on pre-treatment scans and if participants were evaluated by F-18-FDG PET/CT scans at six months post-treatment. Results: One hundred and eight participants (mEHT: HIV-positive n = 25, HIV-negative n = 29; Control Group: HIV-positive n = 26, HIV-negative n = 28) were eligible for analysis. There was a higher CMR of all disease inside and outside the radiation field in the mEHT Group: n = 13 [24.1%] than the control group: n = 3 [5.6%] (Chi squared, Fisher's exact: p = 0.013) with no significant difference in the extra-pelvic response to treatment between the HIV-positive and -negative participants of each group. Conclusion: The CMR of disease outside the radiation field at six months post-treatment provides evidence of an abscopal effect which was significantly associated with the addition of mEHT to treatment protocols. This finding is important as the combined synergistic use of radiotherapy with mEHT could broaden the scope of radiotherapy to include systemic disease

Gated metabolic myocardial imaging, a surrogate for dual perfusion-metabolism imaging by positron emission tomography

Acknowledgments The authors are grateful for the help from Dr H Ali and Dr A Dawson. Funding: This study was performed using a research grant from the Aberdeen Royal Hospitals Trust's Endowment Fund, with further support from the Department of Medical Physics at the University of Aberdeen, for which the authors express their gratitude.Peer reviewedPublisher PD

A glance at imaging bladder cancer.

Purpose: Early and accurate diagnosis of Bladder cancer (BCa) will contribute extensively to the management of the disease. The purpose of this review was to briefly describe the conventional imaging methods and other novel imaging modalities used for early detection of BCa and outline their pros and cons. Methods: Literature search was performed on Pubmed, PMC, and Google scholar for the period of January 2014 to February 2018 and using such words as bladder cancer, bladder tumor, bladder cancer detection, diagnosis and imaging . Results: A total of 81 published papers were retrieved and are included in the review. For patients with hematuria and suspected of BCa, cystoscopy and CT are most commonly recommended. Ultrasonography, MRI, PET/CT using 18F-FDG or 11C-choline and recently PET/MRI using 18F-FDG also play a prominent role in detection of BCa. Conclusion: For initial diagnosis of BCa, cystoscopy is generally performed. However, cystoscopy can not accurately detect carcinoma insitu (CIS) and can not distinguish benign masses from malignant lesions. CT is used in two modes, CT and computed tomographic urography (CTU), both for dignosis and staging of BCa. However, they cannot differentiate T1 and T2 BCa. MRI is performed to diagnose invasive BCa and can differentiate muscle invasive bladder carcinoma (MIBC) from non-muscle invasive bladder carcinoma (NMIBC). However, CT and MRI have low sensitivity for nodal staging. For nodal staging PET/CT is preferred. PET/MRI provides better differentiation of normal and pathologic structures as compared with PET/CT. Nonetheless none of the approaches can address all issues related for the management of BCa. Novel imaging methods that target specific biomarkers, image BCa early and accurately, and stage the disease are warranted

Cytoplasmic p53 couples oncogene-driven glucose metabolism to apoptosis and is a therapeutic target in glioblastoma.

Cross-talk among oncogenic signaling and metabolic pathways may create opportunities for new therapeutic strategies in cancer. Here we show that although acute inhibition of EGFR-driven glucose metabolism induces only minimal cell death, it lowers the apoptotic threshold in a subset of patient-derived glioblastoma (GBM) cells. Mechanistic studies revealed that after attenuated glucose consumption, Bcl-xL blocks cytoplasmic p53 from triggering intrinsic apoptosis. Consequently, targeting of EGFR-driven glucose metabolism in combination with pharmacological stabilization of p53 with the brain-penetrant small molecule idasanutlin resulted in synthetic lethality in orthotopic glioblastoma xenograft models. Notably, neither the degree of EGFR-signaling inhibition nor genetic analysis of EGFR was sufficient to predict sensitivity to this therapeutic combination. However, detection of rapid inhibitory effects on [18F]fluorodeoxyglucose uptake, assessed through noninvasive positron emission tomography, was an effective predictive biomarker of response in vivo. Together, these studies identify a crucial link among oncogene signaling, glucose metabolism, and cytoplasmic p53, which may potentially be exploited for combination therapy in GBM and possibly other malignancies