Skull Base Chordoma and Chondrosarcoma: Neuroradiologist's Guide to Diagnosis, Surgical Management, and Proton Beam Therapy.

Skull base chordomas and chondrosarcomas are distinct types of rare, locally aggressive mesenchymal tumors that share key principles of imaging investigation and multidisciplinary care. Maximal safe surgical resection is the treatment choice for each, often via an expanded endoscopic endonasal approach, with or without multilayer skull base repair. Postoperative adjuvant radiation therapy is frequently administered, usually with particle therapy such as proton beam therapy (PBT).

Biomarkers and Target-Specific Small-Molecule Drugs in Alzheimer's Diagnostic and Therapeutic Research: From Amyloidosis to Tauopathy.

Alzheimer's disease (AD) is the most common type of human dementia and is responsible for over 60% of diagnosed dementia cases worldwide. Abnormal deposition of β-amyloid and the accumulation of neurofibrillary tangles have been recognised as the two pathological hallmarks targeted by AD diagnostic imaging as well as therapeutics. With the progression of pathological studies, the two hallmarks and their related pathways have remained the focus of researchers who seek for AD diagnostic and therapeutic strategies in the past decades.

Venous thromboembolism chemical prophylaxis after skull base surgery.

Purpose: There is no guidance surrounding postoperative venous thromboembolism (VTE) prophylaxis using pharmacological agents (chemoprophylaxis) in patients undergoing skull base surgery. The aim of this study was to compare VTE and intracranial haematoma rates after skull base surgery in patients treated with/without chemoprophylaxis.

Methods: Review of prospective quaternary centre database including adults undergoing first-time skull base surgery (2009-2020).

Synthesis and Preclinical Evaluation of Fluorinated 5-Azaindoles as CB2 PET Radioligands.

Several classes of cannabinoid receptor type 2 radioligands have been evaluated for imaging of neuroinflammation, with successful clinical translation yet to take place. Here we describe the synthesis of fluorinated 5-azaindoles and pharmacological characterization and evaluation of F-radiolabeled analogues. [F] (hCB2 = 96.

Utilizing PET and MALDI Imaging for Discovery of a Targeted Probe for Brain Endocannabinoid /-Hydrolase Domain 6 (ABHD6).

Multimodal imaging provides rich biological information, which can be exploited to study drug activity, disease associated phenotypes, and pharmacological responses. Here we show discovery and validation of a new probe targeting the endocannabinoid α/β-hydrolase domain 6 (ABHD6) enzyme by utilizing positron emission tomography (PET) and matrix-assisted laser desorption/ionization (MALDI) imaging. [F]JZP-MA-11 as the first PET ligand for imaging of the ABHD6 is reported and specific uptake in ABHD6-rich peripheral tissues and major brain regions was demonstrated using PET.

A binge high sucrose diet provokes systemic and cerebral inflammation in rats without inducing obesity.

While the dire cardiometabolic consequences of the hypercaloric modern 'Western' diet are well known, there is not much information on the health impact of a high sucrose diet not inducing weight gain. Here, we tested the hypothesis that rats reared with intermittent binge access to sucrose in addition to normal chow would develop an inflammatory response in brain. To test this hypothesis, we undertook serial PET/MRI scans with the TSPO ligand [F]DPA714 in a group of (n=9) rats at baseline and again after voluntarily consuming 5% sucrose solution three days a week for three months.

GABA receptor density alterations revealed in a mouse model of early moderate prenatal ethanol exposure using [F]AH114726.

Introduction: Prenatal ethanol exposure (PEE) has been shown to alter the level and function of receptors in the brain, one of which is GABA receptors (GABAR), the major inhibitory ligand gated ion channels that mediate neuronal inhibition. High dose PEE in animals resulted in the upregulation of GABAR, but the effects of low and moderate dose PEE at early gestation have not been investigated. This study aimed at examining GABAR density in the adult mouse brain following PEE during a period equivalent to the first 3 to 4 weeks in human gestation.

Defining appropriateness criteria for endoscopic sinus surgery in the management of adult dental implant patients with incidental maxillary sinus findings on conebeam computed tomography.

Objectives: Conebeam computed tomography (CBCT) imaging is commonly requested by dental implant surgeons, preoperatively, for patients being considered for dental implants. Incidental maxillary sinus findings often result in otolaryngology (ENT) referral for further assessment. CBCT findings include transient and benign mucosal changes that may not require any intervention and therefore unnecessarily delay implant surgery.

Development of an automated, GMP compliant FASTlab™ radiosynthesis of [ F]GE-179 for the clinical study of activated NMDA receptors.

N-(2-chloro-5-(S-2-[ F]fluoroethyl)thiophenyl)-N'-(3-thiomethylphenyl)-N'-methylguanidine, ([ F]GE-179), has been identified as a promising positron emission tomography (PET) ligand for the intra-channel phencyclidine (PCP) binding site of the N-methyl-D-aspartate (NMDA) receptor. The radiosynthesis of [ F]GE-179 has only been performed at low radioactivity levels. However, the manufacture of a GMP compliant product at high radioactivity levels was required for clinical studies.

Synthesis and evaluation of 6-[18F]fluoro-3-(pyridin-3-yl)-1H-indole as potential PET tracer for targeting tryptophane 2, 3-dioxygenase (TDO).

Introduction: The increase in expression of tryptophan 2, 3-dioxygenases (TDO) and indoleamine 2,3-dioxygenase (IDO) have been reported as potential tumor biomarkers. TDO and IDO are enzymes that catalyze the first and rate-limiting step of the kynurenine pathway. Positron emitting tomography (PET) tracers investigating the kynurenine pathway may allow for the detection of different disease pathologies in vivo including cancer.

A national survey of functional septorhinoplasty surgery performed in the United Kingdom: a clinician end-user questionnaire to assess current practice and help inform future practice.

Purpose: The aim of this national survey is to assess the current practice of functional septorhinoplasty (SRP) surgery in the UK and better inform future practice.

Methods: An ENT-UK approved questionnaire was sent out to all 135 consultant members of the British Society of Facial Plastic Surgery (BSFPS). Data was collected on numbers of functional SRPs performed on the NHS, use of outcome measures, psychology and photography support, antibiotic use, referral base and consenting practice.

Efficient Distribution of a Novel Zirconium-89 Labeled Anti-cd20 Antibody Following Subcutaneous and Intravenous Administration in Control and Experimental Autoimmune Encephalomyelitis-Variant Mice.

To investigate the imaging and biodistribution of a novel zirconium-89 (Zr)-labeled mouse anti-cd20 monoclonal antibody (mAb) in control and experimental autoimmune encephalomyelitis (EAE) mice following subcutaneous (s. c.) and intravenous (i.

Investigation on the impact of three different quaternary methyl ammonium cartridges on the radiosynthetic yields of [ F]fluoromethyl tosylate.

Our recent investigations for the radiosynthesis of [ F]fluoromethyl tosylate have highlighted that choice of quaternary methyl ammonium (QMA) cartridge used during the radiosynthesis can significantly impact the radiochemical yields. Often the details of the QMA cartridge used in fluourine-18 syntheses are not fully described. However, our studies demonstrate that the type, the size, and nature (method by which it has been conditioned) of the QMA cartridge used during the radiosynthesis can make a significant impact in the labelling efficiency.

Synthesis and in vitro evaluation of fluorine-18 benzimidazole sulfones as CB2 PET-radioligands.

Cannabinoid type 2 receptor (CB2) is up-regulated on activated microglial cells and can potentially be used as a biomarker for PET-imaging of neuroinflammation. In this study the synthesis and pharmacological evaluation of novel fluorinated pyridyl and ethyl sulfone analogues of 2-(tert-butyl)-5-((2-fluoropyridin-4-yl)sulfonyl)-1-(2-methylpentyl)-1H-benzo[d]imidazole (rac-1a) are described. In general, the ligands showed low nanomolar potency (CB2 EC < 10 nM) and excellent selectivity over the CB1 subtype (>10 000×).

Synthesis of F-radiolabeled diphenyl gallium dithiosemicarbazone using a novel halogen exchange method and in vivo biodistribution.

F-radiolabeled diphenyl gallium thiosemicarbazone was prepared by [ F] fluoride exchange of a nitrato anion under mild conditions. The diphenyl gallium thiosemicarbazone chloride is easily prepared in gram quantities and can be used at room temperature in the presence of oxygen. The corresponding nitrate complex is prepared using silver nitrate in methanol solvent and can be stored under nitrogen for weeks before radiolabeling.

N-(4-[F]fluorobenzyl)cholylglycine, a novel tracer for PET of enterohepatic circulation of bile acids: Radiosynthesis and proof-of-concept studies in rats.

Introduction: Enterohepatic circulation (EHC) of conjugated bile acids is an important physiological process crucial for regulation of intracellular concentrations of bile acids and their function as detergents and signal carriers. Only few bile acid-derived imaging agents have been synthesized and hitherto none have been evaluated for studies of EHC. We hypothesized that N-(4-[F]fluorobenzyl)cholylglycine ([F]FBCGly), a novel fluorine-18 labeled derivative of endogenous cholylglycine, would be a suitable tracer for PET of the EHC of conjugated bile acids, and we report here a radiosynthesis of [F]FBCGly and a proof-of-concept study by PET/MR in rats.

Ectopic Cushing's syndrome secondary to olfactory neuroblastoma.

We present the case of a patient with Cushing's syndrome secondary to ectopic ACTH secretion. A MR of the head showed a left-sided nasal mass extending down from the cribriform plate. The patient underwent endoscopic resection with nearly complete removal of the mass.

Hydrothermal synthesis of Group 13 metal trifluoride complexes with neutral N-donor ligands.

The reactions of the hydrated Group 13 fluorides, MF3·3H2O (M = Al, Ga or In) with 2,2':6',2''-terpyridyl, 2,2'-bipyridyl or 1,10-phenanthroline under hydrothermal conditions (180 °C/15 h) produced high yields of the complexes [MF3(terpy)]·3H2O, [MF3(bipy)(OH2)]·2H2O and [MF3(phen)(OH2)]. X-Ray crystal structures of [M'F3(terpy)]·3H2O (M' = Al or Ga), [M'F3(bipy)(OH2)]·2H2O and [GaF3(phen)(OH2)] show that all of them contain distorted octahedral geometries at the metal with mer-trifluoride coordination. Extensive H-bonding (FH-OH) links the molecules.

Infiltrative mass of the skull base and nasopharynx: A diagnostic conundrum.

Inflammatory skull base masses are enigmatic and often behaviourally unpredictable. We present a case of idiopathic hypertrophic pachymeningitis (IHP) forming a central skull base mass to illustrate the process required when one investigates such skull base lesions. This is the first description of mass forming or tumefactive IHP extending into the nasopharynx.

Radiofluorination of a pre-formed gallium(III) aza-macrocyclic complex: towards next-generation positron emission tomography (PET) imaging agents.

As part of a study to investigate the factors influencing the development of new, more effective metal-complex-based positron emission tomography (PET) imaging agents, the distorted octahedral complex, [GaCl(L)]⋅2 H2O has been prepared by reaction of 1-benzyl-1,4,7-triazacyclononane-4,7-dicarboxylic acid hydrochloride (H2L⋅HCl) with Ga(NO3)3⋅9 H2O, which is a convenient source of Ga(III) for reactions in water. Spectroscopic and crystallographic data for [GaCl(L)]⋅2 H2O are described, together with the crystal structure of [GaCl(L)]⋅MeCN. Fluorination of this complex by Cl(-)/F(-) exchange was achieved in high yield by treatment with KF in water at room temperature over 90 minutes, although the reaction was complete in approximately 30 minutes if heated to 80 °C, giving [GaF(L)]⋅2 H2O in good yield.

[GaF3(BzMe2-tacn)]--a neutral 'metalloligand' towards alkali metal and ammonium cations in water.

The neutral complex, [GaF3(L)] (L = 1-benzyl-4,7-dimethyl-1,4,7-triazacyclononane, BzMe2-tacn), acts as a 'metalloligand' to Na(+), K(+) and [NH4](+) cations in aqueous solution, forming supramolecular assemblies containing significant Na/K-F and H3N(+)H···F coordination. κ(1)-[BF4](-) and κ(2)-[PF6](-) coordination is also evident to Na(+) and K(+), respectively.

Three methods for 18F labeling of the HER2-binding affibody molecule Z(HER2:2891) including preclinical assessment.

Unlabelled: Human epidermal growth factor receptor (HER2)-targeted Affibody molecules radiolabeled with (18)F allow the noninvasive assessment of HER2 status in vivo through PET imaging. Such agents have the potential to improve patient management by selecting individuals for HER2-targeted therapies and allowing therapy monitoring. The aim of this study was to assess different (18)F radiolabeling strategies of the HER2-specific Affibody molecule Z(HER2:2891), preclinically determine the biologic efficacy of the different radiolabel molecules, and select a preferred radiolabeling strategy to progress for automated manufacture.

Nickel-mediated radioiodination of aryl and heteroaryl bromides: rapid synthesis of tracers for SPECT imaging.

Rapid and efficient radioiodination of aryl and heteroaryl bromides has been achieved using a nickel(0)-mediated halogen-exchange reaction. This transformation gives direct access to [(123)I]- and [(125)I]-imaging agents for single photon emission computed tomography (SPECT), such as 5-[(123)I]-A85380 (see scheme, Boc = tert-butyloxycarbonyl, cod = 1,5-cyclooctadiene, TFA = trifluoroacetic acid).