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Background Despite the demonstrated adverse outcome, it is difficult to early identify the risks for patients with ischemia and no obstructive coronary artery disease (INOCA). We aimed to explore the prognostic potential of CZT SPECT in INOCA patients. Methods The study population consisted of a retrospective cohort of 118 INOCA patients, all of whom underwent CZT SPECT imaging and invasive coronary angiography (ICA). Dynamic data were reconstructed, and MBF was quantified using net retention model. Major adverse cardiovascular events (MACEs) were defined as cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, heart failure, late coronary revascularization, or hospitalization for unstable angina. Results During a median follow-up of 15 months (interquartile range (IQR) 11–20), 19 (16.1%) MACEs occurred; both stress myocardial blood flow (sMBF) ($$p p < 0.001 ) and coronary flow reserve (CFR) ($$p p < 0.001 ) were significantly lower in the MACE group. Optimal thresholds of sMBF$$p=0.001$$ p = 0.001 ) and CFR (HR: 6.51; 95% CI 1.43–29.65; $$p=0.01$$ p = 0.01 ) were identified as prognostic factors for MACEs. Only sMBF$$p=0.005$$ p = 0.005 ) remained a robust predictor when sMBF and CFR were integrated considered. Compared with CFR, sMBF provides better prognostic model discrimination and reclassification ability (C-index improvement = 0.06, $$p=0.02$$ p = 0.02 ; net reclassification improvement (NRI) = 0.19; integrated discrimination improvement (IDI) = 0.10). Conclusion The preliminary results demonstrated that quantitative analysis on CZT SPECT provides prognostic value for INOCA patients, which may allow the stratification for early prevention and intervention.

Drug delivery to the colon offers great promise for local treatment of colonic diseases as it allows bypassing systemic absorption in the small intestine, thereby increasing luminal drug concentrations in the colon. The primary objective of this in vivo pharmaco-scintigraphy study was to assess the colon drug targeting accuracy of a metronidazole benzoate colonic drug delivery system intended for local treatment of Clostridioides difficile infections. Additionally, it was assessed if the concept of mucoadhesion would increase colonic residence time and promote higher drug bioavailability. Two different capsule formulations were designed and tested in healthy human subjects. Capsules contained either non-mucoadhesive (NM) or mucoadhesive (M) microgranules, both loaded with 100 mg metronidazole benzoate (antibiotic prodrug) and 5 mg samarium oxide (scintigraphy tracer). Filled capsules were coated with a colonic-targeting technology consisting of two functional layers, which allow for accelerated drug release mediated by the intestinal pH in combination with or without colonic bacteria. Coated capsules were neutron-activated to yield the radioisotope 153Sm prior to administration to 18 healthy subjects. Gamma-scintigraphy imaging was combined with the measurement of drug plasma levels. Formulation NM showed high colon-targeting accuracy. Initial capsule disintegration within the targeted ileocolonic region was observed in 8 out of 9 subjects (89%) with colonic arrival times in the range of 3.5 to 12 h and reduced systemic exposure. In contrast, the mucoadhesive formulation M showed some inconsistency regarding the site of initial capsule disintegration (targeting accuracy 56%). Variability of drug release was attributed to self-adhesion and agglomeration of the mucoadhesive microparticles within the capsule. Accurate ileocolonic delivery of metronidazole-loaded microgranules was achieved following oral administration of colonic-targeted capsules. Delayed drug release from NM microparticles in the colon leads to a reduced systemic exposure compared to immediate-release data from literature and presumably elevated drug concentrations in the colonic lumen. This approach offers promising options for the local treatment of colonic diseases.

Cardiovascular disease (CVD) is the leading cause of mortality and disability in developed countries. According to WHO, an estimated 17.9 million people died from CVDs in 2019, representing 32% of all global deaths. Of these deaths, 85% were due to major adverse cardiac and cerebral events. Early detection and care for individuals at high risk could save lives, alleviate suffering, and diminish economic burden associated with these diseases. Carotid artery disease is not only a well-established risk factor for ischemic stroke, contributing to 10%-20% of strokes or transient ischemic attacks (TIAs), but it is also a surrogate marker of generalized atherosclerosis and a predictor of cardiovascular events. In addition to diligent history, physical examination, and laboratory detection of metabolic abnormalities leading to vascular changes, imaging of carotid arteries adds very important information in assessing stroke and overall cardiovascular risk. Spanning from carotid intima-media thickness (IMT) measurements in arteriopathy to plaque burden, morphology and biology in more advanced disease, imaging of carotid arteries could help not only in stroke prevention but also in ameliorating cardiovascular events in other territories (e.g. in the coronary arteries). While ultrasound is the most widely available and affordable imaging methods, computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), their combination and other more sophisticated methods have introduced novel concepts in detection of carotid plaque characteristics and risk assessment of stroke and other cardiovascular events. However, in addition to robust progress in usage of these methods, all of them have limitations which should be taken into account. The main purpose of this consensus document is to discuss pros but also cons in clinical, epidemiological and research use of all these techniques.

Aim Positron Emission Tomography with Computed Tomography (PET/CT) has been proven to be useful in the definition of Radiotherapy (RT) target volume. In this regard, the present expert review summarizes existing data for pancreas, prostate, gynecological and rectum/anal cancer. Methods A comprehensive search of published original article was made, based on SCOPUS and PubMed database, selecting the paper that evaluated the role of PET/CT in the definition of RT volume. Results FDG-PET has an important and promising role for pancreatic cancer. Choline PET/CT could be useful for identifying high-risk volumes for prostate cancer; while PSMA PET/CT is still under evaluation. FDG PET/CT in gynecological cancers has been shown to impact external-beam RT planning. The role of FDG-PET for Gross Tumor volume identification is crucial, representing a useful and powerful tool for anal and rectal cancer. Conclusion Taken together, molecular and functional imaging approaches offer a major step to individualize radiotherapeutic approach.

The pathological accumulation of different peptides is the common base of many neurodegenerative processes, such as Alzheimer’s disease (AD). AD is characterized by amyloid deposits which may cause alterations in neurotransmission, activation of inflammatory mechanisms, neuronal death and cerebral atrophy. Diagnosis in vivo is challenging as the criteria rely mainly on clinical manifestations, which become evident only in a late stage of the disease. While AD can currently be definitively confirmed by postmortem histopathologic examination, in vivo imaging may improve the clinician's ability to identify AD at the earliest stage. In this regard, the detection of cerebral amyloid plaques with positron emission tomography (PET) is likely to improve diagnosis and allow for a prompt start of an effective therapy. Many PET imaging probes for AD-specific pathological modifications have been developed and proved effective in detecting amyloid deposits in vivo. We here review the current knowledge on PET imaging in the detection of amyloid deposits and their application in the diagnosis of AD.

Life-threatening ventricular arrhythmias (VA) are a major cause of death in patients with congestive heart failure (HF). Among various factors, the sympathetic nervous system may give rise to VA in several pathophysiological pathways due to an impaired function of presynaptic sympathetic nerve terminals. Positron emission tomography (PET) with labeled catecholamine analogues represents a reliable tool to assess the sympathetic innervation activity. This review aims at summarising the most relevant and recent literature findings on the current role of PET in the evaluation of cardiac sympathetic activity in patients with heart failure. A comprehensive literature search strategy using PubMed databases was carried out looking for articles on the role of Positron emission tomography/Computed Tomography (PET/CT) in the assessment of myocardial sympathetic innervation in patients with heart failure. The literature search limited to the last 5 years retrieved 40 papers. Most of the papers dealt with PET studies with 11C-HED. 19 pre-clinical, first-in-human and clinical studies highlighting the current role of PET and future perspectives resulted eligible for inclusion in the present review. The assessment of myocardial sympathetic activity in patients with heart failure with PET will play a pivotal role in clinical practice. Its capability to predict the occurrence of life-threatening VA and the effectiveness of resynchronization therapy makes this technique ideal in the era of personalized medicine.

We discuss the current role of PET/CT in all phases of disease in RCC, potential advancements in the diagnostic and prognostic work up, including future perspectives regarding novel radiopharmaceuticals agents. A comprehensive search strategy was used based on SCOPUS and PubMed databases. From all studies published in English, we selected—for this Expert Review—the most relevant articles evaluating the use of PET/CT for the diagnostic assessment of patients with renal cancer. The use of PET/CT in RCC is still very limited due to low sensitivity in some cases, fragmentary data, and scarce numerosity of clinical trials in this setting. However, new potential applications have been proposed for the staging and restaging process of RCC with potential prognostic role, as well new radiotracers for the evaluation of tumor proliferation, neoangiogenesis, and to assess the response to target therapies. In high-risk patients, 18F-FDG PET/CT may be useful for preoperative staging, in the restaging process and to monitor targeted molecular therapies such as tyrosine kinase inhibitors. A new scenario could be open for risk stratification assessment using 18F-FDG PET/CT. New radiopharmaceuticals agents have been proposed; however, further trials are warranted to establish their role in clinical setting.

Despite the widely increasing use of PET/CT for all cancers, the clinical role of this imaging modality in germ cell testicular cancer (GCTC) is still unclear, since controversial results have been achieved by previous studies and few large trials have investigated its potential application in this setting. In this review, we discuss the current state of the art of PET/CT exploring its role in the diagnostic and prognostic work-up in all phases of disease in GCTC and the potential application of new radiopharmaceuticals tracers.

The present review focuses on the current literature about the role of positron emission tomography (PET) imaging in the evaluation of response to treatment in patients with bone sarcomas. Osteosarcoma and Ewing sarcoma are the most frequent primary bone tumours occurring in the paediatric age. Imaging methods are attractive since they offer a non-invasive approach to evaluate response to treatment and are of particular interest in those patients with non-resectable tumours, for whom full histological assessment cannot be obtained. While conventional radiologic imaging can only assess the occurrence of structural changes in malignant tumours, molecular imaging by means of 18F-fluoro-2-deoxyglucose positron emission tomography/computed tomography ([18F]FDG–PET/CT) provides useful information about tumour metabolism, which is more likely to reflect response to treatment. As metabolic changes occur early during the treatment, an earlier assessment of tumour response may be feasible by means of [18F]FDG–PET/CT than using conventional imaging. As such, [18F]FDG–PET/CT may provide useful information for prognosis and clinical management of sarcoma patients. In contrast to OS, there is still some uncertainty in ES patients as to whether a massive SUVmax reduction in FDG–PET correlates with good histopathological response, despite a strong reduction of FDG uptake after the completion of neoadjuvant treatment.

Autoimmune limbic encephalitis (LE) is a rare disorder; its diagnosis can be challenging. We report two uncommon cases of LE evaluated by brain 2-deoxy-2-[18F]fluoro-d-glucose ((18)F-FDG) positron emission tomography/computed tomography describing the metabolic imaging patterns, which were different from those observed in previous studies: the first one presented an unprecedented (18)F-FDG brain mixed pattern, involving also the midbrain, despite negative magnetic resonance imaging exams; the second one showed migrating foci of hypermetabolism, one of which turned into hypometabolism at a later examination.

BackgroundIdiopathic cervical dystonia [ICD] is characterized by an abnormal head and neck posture attributable to involuntary tonic or phasic contractions of neck muscles.FindingsWe performed a brain fluorine-18 fluorodeoxyglucose positron emission tomography/computerized tomography [F18-FDG PET/CT] scan for suspected metabolic alterations in basal ganglia in a 51-year-old woman without any evidence of secondary dystonia. Brain uptake was unremarkable, whereas an increased F18-FDG uptake was observed in the right trapezius and right longus colli muscle, allowing a diagnosis of ICD.ConclusionAn F18 PET/CT may be a non-invasive alternative to electromyography to identify dystonic cervical muscles and this identification could lead to successful clinical results after targeted intramuscular botulinum toxin treatment.

Although 18F-fluoro-deoxy-glucose (FDG) positron emission tomography (PET) has been widely validated and extensively used in the latest years in clinical practice, interpretation of PET/CT images can be affected by several pitfalls. We here present a case of intense lung uptake in a patient without a corresponding finding on CT images, probably due to a microembolism produced during the injection process and located in small vascular structures of the lung parenchyma.

Sarcoidosis is a systemic chronic inflammatory disease of unknown aetiology, characterised by granulomatous lesions with heterogeneous clinical manifestations affecting multiple organs and tissues. Although the respiratory system is most commonly affected, the disease may also present with bone lesions. We report the case of a 31-year-old woman who presented with low back pain and no history of cancer and who was found to have suspicious lesions involving the entire spine on magnetic resonance imaging (MRI). The patient underwent 18F-fluorodeoxyglucose (FDG) PET/CT to search for a primary tumour and for staging purposes. 18F-FDG PET/CT revealed a pattern of hypermetabolic activity in widespread skeletal lesions and in a single left cervical lymph node. The primary tumour was not found, thus suggesting a haematologic disorder. Subsequent biopsies of a cervical lymph node and of bone tissue from L4 revealed active sarcoidosis with no evidence of cancer. This underlines the importance of considering all alternatives when hypermetabolic lesions are found on 18F-FDG PET/CT. Furthermore, 18F-FDG PET can be very useful to indicate accessible sites for guiding fine-needle aspiration cytology (FNAC).