Cryoneurolysis versus radiofrequency ablation outcome on pain experience in chronic low back pain (COPE): a single-blinded randomised controlled trial.

OBJECTIVE: A comparison of cryoneurolysis or radio frequency (RF) with placebo in patients with facetogenic chronic low back pain (LBP) for patient global impression of change (PGIC), pain intensity, function and quality of life, with 1-year follow-up. DESIGN: Single-centre, single-blinded placebo-controlled randomised controlled trial. SETTING: Single-centre study. PARTICIPANTS: Inclusion from March 2020 to September 2022: consenting adults over 18 years of age, LBP>3 months, average Numeric Rating Scale LBP≥4 average last 14 days and a positive response to a diagnostic medial branch block (>50% pain reduction after 60 min). INTERVENTIONS: 120 patients were block randomised 1:1:1 to cryoneurolysis, RF or placebo of the medial branch nerves. Physical therapy was added after 4 weeks for all groups. MAIN OUTCOME MEASURES: Primary outcome was PGIC 4 weeks after the intervention. Secondary outcomes included pain intensity (Numeric Rating Scale, NRS), quality of life (Short Form 36, EQ-5D-5L), disability (Oswestry Disability Index), depression (Major Depression Inventory) and catastrophising (Pain Catastrophising Scale). Outcomes were measured at 4 weeks, 3, 6 and 12 months. RESULTS: There was no statistically significant difference in PGIC at 4 weeks between cryoneurolysis and placebo (risk ratio (RR) 2; 95% CI 0.75 to 5.33, p=0.17) and RF and placebo (RR 1.6; 95% CI 0.57 to 4.49, p=0.37), except PGIC for cryoneurolysis at 6-month follow-up (RR 5.1; 95% CI 1.20 to 22.03, p=0.03). No statistically significant differences were found in secondary follow-up endpoints. CONCLUSIONS: Denervation of the medial branch nerve by either cryoneurolysis or RF compared with placebo did not demonstrate significant improvement in PGIC, pain intensity, function and quality of life in patients with facetogenic chronic LBP at short-term or long-term follow-up. TRIAL REGISTRATION NUMBER: NCT04786145.

The HortONS study. Treatment of chronic cluster headache with transcutaneous electrical nerve stimulation and occipital nerve stimulation: study protocol for a prospective, investigator-initiated, double-blinded, randomized, placebo-controlled trial.

BACKGROUND: Chronic cluster headache (CCH) is a debilitating primary headache disorder. Occipital nerve stimulation (ONS) has shown the potential to reduce attack frequency, but the occipital paresthesia evoked by conventional (tonic) stimulation challenges a blinded comparison of active stimulation and placebo. Burst ONS offers paresthesia-free stimulation, enabling a blinded, placebo-controlled study. Identification of a feasible preoperative test would help select the best candidates for implantation. This study aims to explore ONS as a preventive treatment for CCH, comparing burst stimulation to tonic stimulation and placebo, and possibly identifying a potential preoperative predictor. METHODS: An investigator-initiated, double-blinded, randomized, placebo-controlled trial is conducted, including 40 patients with CCH. Eligible patients complete a trial with the following elements: I) four weeks of baseline observation, II) 12 weeks of transcutaneous electrical nerve stimulation (TENS) of the occipital nerves, III) implantation of a full ONS system followed by 2 week grace period, IV) 12 weeks of blinded trial with 1:1 randomization to either placebo (deactivated ONS system) or burst (paresthesia-free) stimulation, and V) 12 weeks of tonic stimulation. The primary outcomes are the reduction in headache attack frequency with TENS and ONS and treatment safety. Secondary outcomes are treatment efficacy of burst versus tonic ONS, the feasibility of TENS as a predictor for ONS outcome, reduction in headache pain intensity (numeric rating scale), reduction in background headache, the patient's impression of change (PGIC), health-related quality of life (EuroQoL-5D), self-reported sleep quality, and symptoms of anxiety and depression (Hospital Anxiety and Depression Scale, HADS). Data on headache attack characteristics are registered weekly. Data on patient-reported outcomes are assessed after each trial phase. DISCUSSION: The study design allows a comparison between burst ONS and placebo in refractory CCH and enables a comparison of the efficacy of burst and tonic ONS. It will provide information about the effect of burst ONS and explore whether the addition of this stimulation paradigm may improve stimulation protocols. TENS is evaluated as a feasible preoperative screening tool for ONS outcomes by comparing the effect of attack prevention of TENS and tonic ONS. TRIAL REGISTRATION: The study is registered at Clinicaltrials.gov (trial registration number NCT05023460, registration date 07-27-2023).

Treatment of chronic cluster headache with burst and tonic occipital nerve stimulation: A case series.

OBJECTIVES AND BACKGROUND: Chronic cluster headache (CCH) is a rare but severely debilitating primary headache condition. A growing amount of evidence suggests that occipital nerve stimulation (ONS) can offer effective treatment in patients with severe CCH for whom conventional medical therapy does not have a sufficient effect. The paresthesia evoked by conventional (tonic) stimulation can be bothersome and may thus limit therapy. Burst ONS produces paresthesia-free stimulation, but the amount of evidence on the efficacy of burst ONS as a treatment for intractable CCH is scarce. METHODS: In this case series, we report 15 patients with CCH treated with ONS at Aarhus University Hospital, Denmark, from 2013 to 2020. Nine of these received burst stimulation either as primary treatment or as a supplement to tonic stimulation. The results were assessed in terms of the frequency of headache attacks per week and their intensity on the Numeric Rating Scale, as well as the Patient Global Impression of Change (PGIC) with ONS treatment. RESULTS: At a median (range) follow-up of 38 (16-96) months, 12 of the 15 patients (80%) reported a reduction in attack frequency of ≥50% (a reduction from a median of 35 to 1 attack/week, p < 0.001). Seven of these patients were treated with burst ONS. A significant reduction was also seen in maximum pain intensity. Overall, 10 patients stated a clinically important improvement in their headache condition following ONS treatment, rated on the PGIC scale. A total of 16 adverse events (nine of which were in the same patient) were registered. CONCLUSION: Occipital nerve stimulation significantly reduced the number of weekly headache attacks and their intensity. Burst ONS seems to function well alone or as a supplement to conventional tonic ONS as a preventive treatment for CCH; however, larger prospective studies are needed to determine whether the effect can be confirmed and whether the efficacy of the two stimulation paradigms is even.

Virtual Reality Treatment of Severe Neuropathic Pain in an Adolescent Child: A Case Report.

We describe virtual reality (VR) used as an effective intervention to treat severe chronic neuropathic pain in an otherwise healthy adolescent boy. The patient presented with severe pain and allodynia in the right foot after calcaneus extension surgery. Multiple medical and psychological interventions were unsuccessful over 3 years, with the pain leading the patient to drop out of school. VR gaming intervention provided the patient with significant pain relief and substantial improvement in functionality. This case report details the VR intervention and its effect on the patient's severe, medically refractory pain syndrome.

Combined In Vivo Microdialysis and PET Studies to Validate [11C]Yohimbine Binding as a Marker of Noradrenaline Release.

The noradrenaline system attracts attention for its role in mood disorders and neurodegenerative diseases but the lack of well-validated methods impairs our understanding when assessing its function and release in vivo. This study combines simultaneous positron emission tomography (PET) and microdialysis to explore if [11C]yohimbine, a selective antagonist radioligand of the α2 adrenoceptors, may be used to assess in vivo changes in synaptic noradrenaline during acute pharmacological challenges. Anesthetised Göttingen minipigs were positioned in a head holder in a PET/CT device. Microdialysis probes were placed in the thalamus, striatum and cortex and dialysis samples were collected every 10 min. Three 90 min [11C]yohimbine scans were acquired: at baseline and at two timepoints after the administration of amphetamine (1-10 mg/kg), a non-specific releaser of dopamine and noradrenaline, or nisoxetine (1 mg/kg), a specific noradrenaline transporter inhibitor. [11C]yohimbine volumes of distribution (VT) were obtained using the Logan kinetic model. Both challenges induced a significant decrease in yohimbine VT, with time courses reflecting their different mechanisms of action. Dialysis samples revealed a significant increase in noradrenaline extracellular concentrations after challenge and an inverse correlation with changes in yohimbine VT. These data suggest that [11C]yohimbine can be used to evaluate acute variations in synaptic noradrenaline concentrations after pharmacological challenges.

Burst Spinal Cord Stimulation in Pregnancy: First Clinical Experiences.

OBJECTIVES: Spinal cord stimulation (SCS) is a treatment for chronic neuropathic pain. It is based on the delivery of electric impulses to the spinal cord, traditionally in a regular square-wave pattern ("tonic" stimulation) and, more recently, in a rhythmic train-of-five "BurstDR" pattern. The safety of active SCS therapy in pregnancy is not established, and recommendations are based on limited casuistic evidence. We present in this study clinical data on a case series of six women treated with burst SCS during pregnancy. In addition, we present the ultrasonographic flow measurements of fetal and uteroplacental blood flow in a pregnant patient. MATERIALS AND METHODS: Patients were included if they had been implanted with a full SCS system at Aarhus University Hospital, Denmark, between 2006 and 2020 and received active burst SCS stimulation during a pregnancy. Telephone interviews were conducted, including details on SCS therapy, medication, pregnancy course and outcome, and health status of the offspring. In one patient, the uteroplacental and fetal blood flow was assessed in gestational week 29 by Doppler flow measurements performed during both ON and OFF phases of the SCS system. RESULTS: Six patients were included with a total of 11 pregnancies. Three pregnancies ended in miscarriages, all in the same patient who had preexisting significant risk factors for miscarriage. Eight resulted in a live-born child with normal birth weight for gestational age; seven were born at term, and one was born late preterm, in gestational week 36. Ultrasonographic Doppler flow, measured in one patient, was normal and did not reveal any immediate changes between burst SCS ON and OFF. Seven children were reported healthy with normal neurodevelopment and one physically healthy but with developmental delays. CONCLUSIONS: The data presented in this study add to the accumulating evidence of the safety of SCS in pregnancy.

Spinal cord stimulation therapy for patients with Parkinson's disease and gait problems (STEP-PD): study protocol for an exploratory, double-blind, randomised, placebo-controlled feasibility trial.

Introduction: Gait difficulties are common in Parkinson's disease (PD) and cause significant disability. These symptoms are often resistant to treatment. Spinal cord stimulation (SCS) has been found to improve gait, including freezing of gait, in a small number of patients with PD. The mechanism of action is unclear, and some patients are non-responders. With this double-blind, placebo-controlled efficacy and feasibility clinical and imaging study, we aim to shed light on the mechanism of action of SCS and collect data to inform development of a scientifically sound clinical trial protocol. We also aim to identify clinical and imaging biomarkers at baseline that could be predictive of a favourable or a negative outcome of SCS and improve patient selection. Methods and analysis: A total of 14 patients will be assessed with clinical rating scales and gait evaluations at baseline, and at 6 and 12 months after SCS implantation. They will also receive serial 18F-deoxyglucose and 18FEOBV PET scans to assess the effects of SCS on cortical/subcortical activity and brain cholinergic function. The first two patients will be included in an open pilot study while the rest will be randomised to receive active treatment or placebo (no stimulation) for 6 months. From this point, the entire cohort will enter an open label active treatment phase for a subsequent 6 months. Ethics and dissemination: This study was reviewed and approved by the Committee on Health Research Ethics, Central Denmark RM. It is funded by the Danish Council for Independent Research. Independent of outcome, the results will be published in peer-reviewed journals and presented at national and international conferences. Trial registration number: NCT05110053; ClinicalTrials.gov Identifier.

An fMRI-compatible system for targeted electrical stimulation.

BACKGROUND: Neuromodulation is a rapidly expanding therapeutic option considered within neuropsychiatry, pain and rehabilitation therapy. Combining electrostimulation with feedback from fMRI can provide information about the mechanisms underlying the therapeutic effects, but so far, such studies have been hampered by the lack of technology to conduct safe and accurate experiments. Here we present a system for fMRI compatible electrical stimulation, and the first proof-of-concept neuroimaging data with deep brain stimulation (DBS) in pigs obtained with the device. NEW METHOD: The system consists of two modules, placed in the control and scanner room, connected by optical fiber. The system also connects to the MRI scanner to timely initiate the stimulation sequence at start of scan. We evaluated the system in four pigs with DBS in the subthalamic nucleus (STN) while we acquired BOLD responses in the STN and neocortex. RESULTS: We found that the system delivered robust electrical stimuli to the implanted electrode in sync with the preprogrammed fMRI sequence. All pigs displayed a DBS-STN induced neocortical BOLD response, but none in the STN. COMPARISONS WITH EXISTING METHOD: The system solves three major problems related to electric stimuli and fMRI examinations, namely preventing distortion of the fMRI signal, enabling communication that synchronize the experimental conditions, and surmounting the safety hazards caused by interference with the MRI scanner. CONCLUSIONS: The fMRI compatible electrical stimulator circumvents previous problems related to electroceuticals and fMRI. The system allows flexible modifications for fMRI designs and stimulation parameters, and can be customized to electroceutical applications beyond DBS.

Interventions to improve gait in Parkinson's disease: a systematic review of randomized controlled trials and network meta-analysis.

INTRODUCTION: Disabling gait symptoms, especially freezing of gait (FoG), represents a milestone in the progression of Parkinson's disease (PD). This systematic review and network meta-analysis assessed and ranked interventions according to their effectiveness in treating gait symptoms in people with PD across four different groups of gait measures. METHODS: A systematic search was carried out across PubMed, EMBASE, PubMed Central (PMC), and Cochrane Central Library from January 2000 to April 2021. All interventions, or combinations, were included. The primary outcome was changes in objective gait measures, before and after intervention. Outcome measures in the included studies were stratified into four different types of gait outcome measures; dynamic gait, fitness, balance, and freezing of gait. For the statistical analysis, five direct head-to-head comparisons of interventions, as well as indirect comparisons were performed. Corresponding forest plots ranking the interventions were generated. RESULTS: The search returned 6288 articles. From these, 148 articles could be included. Of the four different groups of measurement, three were consistent, meaning that there was agreement between direct and indirect evidence. The groups with consistent evidence were dynamic gait, fitness, and freezing of gait. For dynamic gait measures, treatments with the largest observed effect were Aquatic Therapy with dual task exercising (SMD 1.99 [- 1.00; 4.98]) and strength and balance training (SMD 1.95 [- 0.20; 4.11]). For measures of fitness, treatments with the largest observed effects were aquatic therapy (SMD 3.41 [2.11; 4.71] and high-frequency repetitive transcranial magnetic stimulation (SMD 2.51 [1.48; 3.55]). For FoG measures, none of the included interventions yielded significant results. CONCLUSION: Some interventions can ameliorate gait impairment in people with PD. No recommendations on a superior intervention can be made. None of the studied interventions proved to be efficacious in the treatment of FoG. PROSPERO (registration ID CRD42021264076).

Anterograde Tracing From the Göttingen Minipig Motor and Prefrontal Cortex Displays a Topographic Subthalamic and Striatal Axonal Termination Pattern Comparable to Previous Findings in Primates.

Background: Deep brain stimulation (DBS) of the dorsal subthalamic nucleus (STN) is a validated neurosurgical treatment of Parkinson's Disease (PD). To investigate the mechanism of action, including potential DBS induced neuroplasticity, we have previously used a minipig model of Parkinson's Disease, although the basal ganglia circuitry was not elucidated in detail. Aim: To describe the cortical projections from the primary motor cortex (M1) to the basal ganglia and confirm the presence of a cortico-striatal pathway and a hyperdirect pathway to the subthalamic nucleus, respectively, which is known to exist in primates. Materials and Methods: Five female Göttingen minipigs were injected into the primary motor cortex (n = 4) and adjacent prefrontal cortex (n = 1) with the anterograde neuronal tracer, Biotinylated Dextran Amine (BDA). 4 weeks later the animals were sacrificed and the brains cryosectioned into 30 µm thick coronal sections for subsequent microscopic analysis. Results: The hyperdirect axonal connections from the primary motor cortex were seen to terminate in the dorsolateral STN, whereas the axonal projections from the prefrontal cortex terminated medially in the STN. Furthermore, striatal tracing from the motor cortex was especially prominent in the dorsolateral putamen and less so in the dorsolateral caudate nucleus. The prefrontal efferents were concentrated mainly in the caudate nucleus and to a smaller degree in the juxtacapsular dorsal putamen, but they were also found in the nucleus accumbens and ventral prefrontal cortex. Discussion: The organization of the Göttingen minipig basal ganglia circuitry is in accordance with previous descriptions in primates. The existence of a cortico-striatal and hyperdirect basal ganglia pathway in this non-primate, large animal model may accordingly permit further translational studies on STN-DBS induced neuroplasticity of major relevance for future DBS treatments.

Dopaminergic Neuromodulation of Spike Timing Dependent Plasticity in Mature Adult Rodent and Human Cortical Neurons.

Synapses in the cerebral cortex constantly change and this dynamic property regulated by the action of neuromodulators such as dopamine (DA), is essential for reward learning and memory. DA modulates spike-timing-dependent plasticity (STDP), a cellular model of learning and memory, in juvenile rodent cortical neurons. However, it is unknown whether this neuromodulation also occurs at excitatory synapses of cortical neurons in mature adult mice or in humans. Cortical layer V pyramidal neurons were recorded with whole cell patch clamp electrophysiology and an extracellular stimulating electrode was used to induce STDP. DA was either bath-applied or optogenetically released in slices from mice. Classical STDP induction protocols triggered non-hebbian excitatory synaptic depression in the mouse or no plasticity at human cortical synapses. DA reverted long term synaptic depression to baseline in mouse via dopamine 2 type receptors or elicited long term synaptic potentiation in human cortical synapses. Furthermore, when DA was applied during an STDP protocol it depressed presynaptic inhibition in the mouse but not in the human cortex. Thus, DA modulates excitatory synaptic plasticity differently in human vs. mouse cortex. The data strengthens the importance of DA in gating cognition in humans, and may inform on therapeutic interventions to recover brain function from diseases.

An Intracortical Implantable Brain-Computer Interface for Telemetric Real-Time Recording and Manipulation of Neuronal Circuits for Closed-Loop Intervention.

Recording and manipulating neuronal ensemble activity is a key requirement in advanced neuromodulatory and behavior studies. Devices capable of both recording and manipulating neuronal activity brain-computer interfaces (BCIs) should ideally operate un-tethered and allow chronic longitudinal manipulations in the freely moving animal. In this study, we designed a new intracortical BCI feasible of telemetric recording and stimulating local gray and white matter of visual neural circuit after irradiation exposure. To increase the translational reliance, we put forward a Göttingen minipig model. The animal was stereotactically irradiated at the level of the visual cortex upon defining the target by a fused cerebral MRI and CT scan. A fully implantable neural telemetry system consisting of a 64 channel intracortical multielectrode array, a telemetry capsule, and an inductive rechargeable battery was then implanted into the visual cortex to record and manipulate local field potentials, and multi-unit activity. We achieved a 3-month stability of the functionality of the un-tethered BCI in terms of telemetric radio-communication, inductive battery charging, and device biocompatibility for 3 months. Finally, we could reliably record the local signature of sub- and suprathreshold neuronal activity in the visual cortex with high bandwidth without complications. The ability to wireless induction charging combined with the entirely implantable design, the rather high recording bandwidth, and the ability to record and stimulate simultaneously put forward a wireless BCI capable of long-term un-tethered real-time communication for causal preclinical circuit-based closed-loop interventions.

Complications and Effects of Dorsal Root Ganglion Stimulation in the Treatment of Chronic Neuropathic Pain: A Nationwide Cohort Study in Denmark.

OBJECTIVES: Dorsal root ganglion (DRG) stimulation is a novel treatment of chronic neuropathic pain and has been shown to be efficacious across several case reports and randomized trials. However, long-term follow-up is limited, as are reports of complication rates. This study presents efficacy and complications for patients treated with DRG stimulation. MATERIALS AND METHODS: We performed an observational, multicenter cohort study of all patients in Denmark implanted with FDA-approved DRG stimulation systems to treat chronic, neuropathic pain between 2014 and 2018. Follow-up period was one to three years. RESULTS: Forty-three patients underwent trial DRG stimulation; 33 were subsequently fully implanted. Pain location: 58% lower extremity; 21% upper extremity; 21% thoracic/abdominal. At the end of the observation period, 58% of fully implanted patients were still implanted; 42% had fully functional systems. In these patients, average Numerical Rating Scale (NRS)-score of pain was reduced from 6.8 to 3.5 (p = 0.00049) and worst NRS-score was reduced from 8.6 to 6.0 (p = 0.0039) at 12 months follow-up. Pain Catastrophizing Score was reduced from 32 to 15 (p = 0.0039). Thirteen patients experienced complications related to defect leads (39% of implanted systems). In four patients (12%), lead removal left fragments in the root canal due to lead fracture, and three patients suffered permanent nerve damage during attempts to replace broken leads. CONCLUSIONS: This study suggests a significant, clinically relevant effect of DRG stimulation on neuropathic pain, but also demonstrates substantial problems with maintenance and revision of currently available systems. Consequently, treatment with equipment marketed specifically for DRG stimulation is currently paused in Denmark.

Pain Catastrophizing Does Not Predict Spinal Cord Stimulation Outcomes: A Cohort Study of 259 Patients With Long-Term Follow-Up.

OBJECTIVE: Spinal cord stimulation (SCS) is an important treatment modality used to treat chronic neuropathic pain. However, reported success rates of 26%-70% entail an increased focus on patient selection. An area of core interest is psychological evaluation, often using scales such as the Pain Catastrophizing Scale (PCS). The aim of this study was to assess the relation between baseline PCS scores obtained before implantation and SCS outcomes defined as (1) Rating on Patients' Global Impression of Change scale (PGIC), (2) Pain relief on the Numeric Rating Scale (NRS), (3) Cessation of pain medication, and (4) Risk of permanent explantation. MATERIALS AND METHODS: Using records from the Neurizon Neuromodulation Database, we performed a multicenter open cohort study of 259 permanently implanted SCS patients. Follow-up ranged from six months to nine years (median = three years). For each of the defined SCS outcomes, patients were grouped according to their latest follow-up registration. Subsequently, we used a one-way ANOVA and exact t-tests to compare mean baseline PCS scores between groups. RESULTS: No difference in mean baseline PCS scores was found between PGIC groups. Baseline PCS scores was not associated with the probability of obtaining 30% or 50% pain relief on latest registration. Baseline PCS scores of patients able to cease all usage of tricyclic antidepressants, antiepileptics, or opioids during SCS treatment did not differ from baseline scores of continuous users. We found no association between baseline PCS scores and risk of permanent explantation. CONCLUSION: This study did not demonstrate any associations between baseline PCS scores and SCS outcomes.

OptimalTTF-1: Enhancing tumor treating fields therapy with skull remodeling surgery. A clinical phase I trial in adult recurrent glioblastoma.

BACKGROUND: Preclinical studies suggest that skull remodeling surgery (SR-surgery) increases the dose of tumor treating fields (TTFields) in glioblastoma (GBM) and prevents wasteful current shunting through the skin. SR-surgery introduces minor skull defects to focus the cancer-inhibiting currents toward the tumor and increase the treatment dose. This study aimed to test the safety and feasibility of this concept in a phase I setting. METHODS: Fifteen adult patients with the first recurrence of GBM were treated with personalized SR-surgery, TTFields, and physician's choice oncological therapy. The primary endpoint was toxicity and secondary endpoints included standard efficacy outcomes. RESULTS: SR-surgery resulted in a mean skull defect area of 10.6 cm2 producing a median TTFields enhancement of 32% (range 25-59%). The median TTFields treatment duration was 6.8 months and the median compliance rate 90%. Patients received either bevacizumab, bevacizumab/irinotecan, or temozolomide rechallenge. We observed 71 adverse events (AEs) of grades 1 (52%), 2 (35%), and 3 (13%). There were no grade 4 or 5 AEs or intervention-related serious AEs. Six patients experienced minor TTFields-induced skin rash. The median progression-free survival (PFS) was 4.6 months and the PFS rate at 6 months was 36%. The median overall survival (OS) was 15.5 months and the OS rate at 12 months was 55%. CONCLUSIONS: TTFields therapy combined with SR-surgery and medical oncological treatment is safe and nontoxic and holds the potential to improve the outcome for GBM patients through focal dose enhancement in the tumor.

Activation of NMDA receptor ion channels by deep brain stimulation in the pig visualised with [18F]GE-179 PET.

BACKGROUND: No PET radioligand has yet demonstrated the capacity to map glutamate N-methyl-d-aspartate receptor ion channel (NMDAR-IC) function. [18F]GE-179 binds to the phencyclidine (PCP) site in open NMDAR-ICs and potentially provides a use-dependent PET biomarker of these ion channels. OBJECTIVE: To show [18F]GE-179 PET can detect increased NMDAR-IC activation during electrical deep brain stimulation (DBS) of pig hippocampus. METHODS: Six minipigs had an electrode implanted into their right hippocampus. They then had a baseline [18F]GE-179 PET scan with DBS turned off followed by a second scan with DBS turned on. Brain [18F]GE-179 uptake at baseline and then during DBS was measured with PET. Cerebral blood flow (CBF) was measured with [15O]H2O PET at baseline and during DBS and parametric CBF images were generated to evaluate DBS induced CBF changes. Functional effects of injecting the PCP blocker MK-801 were also evaluated. Electrode positions were later histologically verified. RESULTS: DBS induced a 47.75% global increase in brain [18F]GE-179 uptake (p = 0.048) compared to baseline. Global CBF was unchanged by hippocampal DBS. [18F]GE-179 PET detected a 5% higher uptake in the implanted compared with the non-implanted temporo-parietal cortex at baseline (p = 0.012) and during stimulation (p = 0.022). Administration of MK-801 before DBS failed to block [18F]GE-179 uptake during stimulation. CONCLUSION: PET detected an increase in global brain [18F]GE-179 uptake during unilateral hippocampal DBS while CBF remained unchanged. These findings support that [18F]GE-179 PET provides a use-dependent marker of abnormal NMDAR-IC activation.

[Tumor treating fields in cancer treatment in Denmark].

Tumor treating fields (TTFields) is a new non-invasive approach to cancer treatment. TTFields is low-intensity (1-5 V/m), intermediate frequency (150-200 kHz) alternating electric fields delivered locally to the tumour to selectively kill dividing cells and disrupt cancer growth. TTFields has proven safe and effective for newly diagnosed glioblastoma and is currently being tried for multiple other tumours. This review presents an introduction to TTFields, covering the main indications, the application method, the mechanism of action, the clinical results and the perspectives for implementation in Danish cancer treatment.