Peptide receptor radionuclide therapy plus somatostatin analogues for a neuroendocrine tumour combined and maintenance treatment

Immunotherapy and 18 F-FDG PET/CT: standardised procedures are needed

Investigations of possible links between Alzheimer’s disease and type 2 diabetes mellitus by positron emission tomography: a systematic review Abstract Purpose To review published evidence of possible links between Alzheimer’s disease (AD) and type-2 diabetes mellitus revealed by positron emission tomography (PET). Methods We searched online databases with keywords diabetes mellitus (DM), AD, and PET. We assessed the studies in terms of purpose, methodology, materials, and relationships between AD and DM suggested by PET imaging. Results After removal of 142 duplicates, 227 hits yielded no more than 15 full-length publications, from which we excluded six for specific reasons. The remaining nine studies were not directly comparable because of differences of purpose, study design, material, and methods. Individual subject materials consisted of 4–154 patients in case–control (4), observational (4), and longitudinal (1) studies, the last including only four DM patients. Mean patient age was 76.4 years (range 45–90). In five studies, researchers examined regional cerebral glucose metabolism with 18F-fluorodeoxyglucose (FDG), in three studies, researchers imaged amyloid with PET, and in one study, they measured both glucose metabolism and amyloid deposition. All four studies of amyloid tracers led to the conclusion that amyloid deposition was unaffected by DM status. Evidence of insulin resistance and increased blood glucose was associated with decreased FDG accumulation in AD signature regions in DM patients. Conclusion The relationships between DM and AD identified by PET appear to be independent of amyloid deposition and predominantly highlighted by reduced glucose metabolism, as suggested by four of the five glucose metabolism studies.

68 Ga-DOTA-peptides PET/MRI in pancreatico-duodenal neuroendocrine tumours: a flash pictorial essay on assets and lacks Abstract Purpose PET with radiolabeled somatostatin receptors (SSTR) analogues, such as 68Ga-DOTATOC, is commonly used in all stages of gastroenteropancreatic neuroendocrine tumours (GEP-NETs). Magnetic resonance Imaging (MRI) has excellent soft-tissue contrast and it is mainly applied in this oncological setting for assessing liver disease. Simultaneous PET/MRI scanners allow the combined acquisition of PET and MRI data with improved patient comfort and reduced radiation dose. The aim of the present pictorial essay is to highlight the assets and limits of fully hybrid PET/MRI in the field of GEP-NETs, presenting significant clinical cases performed in our Centre. Technique and findings PET/MRI protocol: simultaneous PET/MRI acquisition started approximately 60 min after 68Ga-DOTATOC tracer injection; MR localizer was performed to define the number of table positions (PET-FOV) for PET/MRI whole-body acquisition. A dedicated MRI protocol was performed on the abdomen, following the whole-body PET/MRI scan. Conclusion 68Ga-DOTATOC PET/MRI combines the high sensitivity and specificity of 68Ga-DOTATOC PET tracer and MR high-quality imaging, especially for the liver. The clinical setting of GEP-NETs represents an interesting setting of application of this imaging technique, although the pros and cons should be taken into account until further methodological improvements will occur, especially for the characterization of lung findings.

Hybrid cardiac PET/MR: the value of multiparametric assessment in cardiac sarcoidosis Abstract Purpose The advent of hybrid positron emission tomography/magnetic resonance (PET/MR) systems has opened the gate to integrated multiparametric evaluation of patients with suspected cardiac sarcoidosis. The aim of the present paper is to systematically review all available literature to define the role of hybrid PET/MR in patients with confirmed or suspected cardiac sarcoidosis. Methods The review strategy was developed following the PRISMA 2009 statement. An electronic database (Medline, Google Scholar, Clinical Trials.gov) search was conducted to identify articles on hybrid PET/MR in cardiac sarcoidosis. Only reports on hybrid PET/MR systems were considered. All PET tracers were considered. No date limitation was applied. Following duplicate removal, abstracts or full articles in case of case reports were screened for inclusion criteria. The full text of the remaining studies was reviewed. Results Eleven studies were found, including seven case reports, two case series, and two diagnostic accuracy studies. All studies reported feasibility and interpretability of cardiac 18F-FDG PET/MR in cardiac sarcoidosis. The two case series demonstrated non-inferiority of PET/MR compared to PET/CT and, in fact, suggested greater sensitivity. Diagnostic accuracy studies showed satisfactory sensitivity and specificity of PET/MR to diagnose cardiac sarcoidosis. Two reports also showed the usefulness of cardiac PET/MR to assess response to treatment. Conclusion Hybrid cardiac PET/MR is a valuable tool for the diagnosis of cardiac sarcoidosis. Moreover, as it offers activity and tissue characterisation, it can be used to tailor and monitor treatment.

A look ahead: future directions of SSR-directed imaging and therapy in meningioma Abstract Background Meningiomas, which are the most common of CNS tumours in adults, show a high expression of the somatostatin receptor subtype 2 (SSR). Visualization of these receptors with specific PET ligands augments contrast-enhanced MRI and CT of the brain in resolving several clinical issues related to differential diagnosis, evaluation of meningioma extent, and therapy planning or follow-up. Moreover, SSR-directed radioligands labeled with beta-emitters serve for radiopeptide therapy (RPT) in patients with recurrent or refractory meningioma. In the light of recent developments in radiochemistry, neuropathology/molecular genetics, and emerging systemic treatments, we present our perspective on future directions of SSR-directed imaging and therapy in meningioma. Methods We conducted a search in the PubMed literature database until June 2019 using the terms “meningioma”, “PET”, “somatostatin receptor”, “SS(T)R”, “DOTATATE”, “DOTATOC”, “radiopeptide therapy”, “imaging”, “therapy”, “classification” alone and in combination, compiled with relevant literature from the authors’ own files. Results/conclusion Our review identifies important emerging applications of SSR-directed imaging and therapy in patients with meningioma. We summarize the state of development novel SSR-directed radio-ligands, meningioma classifications and systemic treatment options.

Sentinel lymph node biopsy in oral–oropharyngeal squamous cell carcinoma: standards, new technical procedures, and clinical advances Abstract Purpose To provide substantial coverage and critical appraisal of standards as well as new technical procedures and clinical advances concerning sentinel lymph node biopsy (SNB) in oral squamous cell carcinoma (OSCC). Methods The MEDLINE database was searched via the PubMed interface up to January 2019 for the following MeSH heading: “sentinel lymph node biopsy” and “squamous cell carcinoma of head and neck”. Results SNB exists as an alternative to elective neck dissection (END) in OSCC. Pre-surgical planar lymphoscintigraphy with intra-operative hand-held gamma probe allows using SNB. Furthermore, the contribution of pre-surgical SPECT/CT improves the sentinel lymph node (SLN) roadmap in sites that are closer to the injection site. Portable gamma camera and freehand SPECT are not yet routine clinical practice, but can further improve intra-operative SLN detection. However, the difficulty in detecting SLNs located closer to the injection site persists. SNB with combined radioactive and near-infrared fluorescence guidance is an attractive option for improving spatial resolution of radio-guided techniques while maintaining depth penetration. Conclusion Numerous studies have demonstrated that SNB can be proposed for accurate histopathological staging of the neck and the guidelines support the introduction of SNB as an alternative to END in T1/T2 N0 OSCC patients. New hybrid imaging techniques, which are offering new possibilities to assist clinicians and surgeons in localizing the site of uptake in sentinel node detection, need to be confirmed in ongoing and future clinical trials. In the future, the integration of new PET tracers could continue along the route mapped out in SNB.

Advanced approaches to imaging primary breast cancer: an update Abstract Purpose Breast cancer (BC) is the most common cancer in women. Early detection of BC plays an important role in preventing advanced disease and improving survival. In this article, we aim to describe both advantages and limitations of conventional and new BC-imaging modalities. Methods A literature search was performed for the period of January 2013 through October 2018, using search engines such as PubMed, PMC, and Google scholar. Search topics included: “breast cancer”, “breast lesion”, and “breast tumor imaging, diagnosis, and detection”. Results A total of 143 papers which primarily addressed imaging efficacy issues are included in the review. Mammography is the oldest and most commonly utilized screening modality for BC. Ultrasonography (US), computed tomography (CT), magnetic resonance imaging (MRI), positron emission mammography (PEM), and positron emission tomography/computed tomography (PET/CT) are the other conventional BC-imaging modalities. To overcome certain weaknesses of these modalities, new imaging tools including contrast-enhanced spectral mammography (CSEM), digital breast tomosynthesis (DBT), multiparametric (MP)-MRI, microwave imaging, and PET/MRI have been investigated. Conclusion Conventional BC-imaging modalities have both advantages and limitations. When utilized in combination, they are often complementary. For example, a limitation of mammography is low sensitivity in dense breasts. The addition of DBT lessens this limitation by providing three-dimensional (3D) images of the breast that minimizes the effect of overlying breast tissue. Additionally, US added to mammography in dense breasts increases screening sensitivity and has the advantages of accessibility and lack of ionizing radiation. MRI is currently the most sensitive method used for detecting BC. When MRI is not suitable for patients, such as those with prosthesis, dedicated breast CT can be used. Scintimammography is another alternative method, although not commonly performed due to low sensitivity in < 1 cm tumors. Breast-specific gamma imaging (BSGI), on the other hand, can detect breast tumor < 1 cm; however, effective radiation dose is higher than mammography. PEM, with its high resolution, has been developed to image small breast tumors. PET/CT and PET/MRI have also been used to detect BC. Despite complementary roles of conventional imaging techniques, none of them have addressed all issues in BC diagnosis. Research studies developing novel target-specific molecular imaging agents are in progress with hopes to fill gaps in currently available imaging technologies.

PET/MRI for neuroendocrine tumors: a match made in heaven or just another hype? Abstract Purpose To evaluate the current literature on technical feasibility and diagnostic value of PET/MRI in management of patients with neuroendocrine tumors (NETs). Methods A systematic literature search of the PubMed/MEDLINE database identified studies that evaluated the role of simultaneous PET/MRI for the evaluation of neuroendocrine tumors in human subjects. Exclusion criteria included studies lacking simultaneous PET/MRI, absence of other than attenuation-correction MRI pulse sequences, and case reports. No data-pooling or statistical analysis was performed due to the small number of articles and heterogeneity of the methodologies. Results From the 21 identified articles, five were included, which demonstrated successful technical feasibility of simultaneous PET/MRI through various imaging protocols in a total of 105 patients. All articles demonstrated equal or superior detection of liver lesions by PET/MRI over PET/CT. While one study reported superior detection of bone lesions by PET/MRI, two demonstrated favorable detection by PET/CT. Two studies demonstrated superiority of PET/CT in detection of nodal metastases; three studies reported the pitfall of PET/MRI in detection of lung lesion. Conclusion The current literature reports successful technical feasibility of PET/MRI for imaging of NETs. While whole-body PET/CT in conjunction with an abdominal MRI may serve as a comprehensive approach for baseline staging, follow-up with PET/MRI may be preferred for those with liver-only disease. Another possible role for PET/MRI is to provide a multiparametric approach to follow-up of response to treatment. With further advances in MRI imaging acquisitions and post-processing techniques, PET/MRI may become more applicable to a broader group of patients with NETs, and possibly the imaging modality of choice for this patient population.

The eye of nuclear medicine