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Purpose: The purpose of this study was to describe alternative endovascular (EV) techniques and assess their feasibility and efficacy in minimizing failure rates in limb salvage for the treatment of complex below-the knee (BTK) occlusions that could not be crossed with a conventional antegrade access. Materials and Methods: Between December 2007 and November 2010, 1,035 patients (557 male) underwent EV treatment for critical limb ischemia in our institution. In 124 (12% [83 male], mean age 68.2 ± 0.5 years) patients, transfemoral antegrade revascularization attempt failed, and an alternative approach was used. Follow-up was performed at 1 and 6 months. Results were compared with 56 patients treated between November 2002 and November 2007, in whom conventional technique was unsuccessful and unconventional techniques were not adopted. Results: Technical success was achieved in 119 (96%) patients. The limb-salvage rates were 96.8% and 83% at 1- and 6-month follow-up, respectively. Sixteen (12.9%) and 33 (26.6%) patients underwent reintervention at 1- and 6-month follow-up, respectively. Transcutaneous oxygen tension increased at 1 month (44.7 ± 1.1 vs. 15.7 ± 0.8 mmHg; p < 0.001) and remained stable at follow-up. Twenty (16.1%) patients required major amputation. Thirteen (10.4%) patients died during follow-up. In our previous experience, percutaneous transluminal angioplasty failure, amputation, and death rates were 10.9, 39.2, and 23.2%, respectively. Alternative techniques allowed a significant decrease of major amputation and death rates (p = 0.0001 and p = 0.02, respectively). Conclusion: The use of alternative techniques seems feasible in case of a failed antegrade BTK revascularization attempt and could minimize failure rates in the treatment of complex occlusions while providing satisfying clinical success rates at 6 months. [ABSTRACT FROM AUTHOR]

Purpose: The aim of our study was to assess the efficacy and safety of percutaneous osteoplasty (PO), a technical extension of percutaneous vertebroplasty, in the treatment of extraspinal bone lesions from multiple myeloma causing pain resistant to NSAID therapy or treated with opioids.Methods: Between March 2006 and January 2009, 39 patients (22 female), median age 64 years (range 48-88 years) with diagnosis of multiple myeloma, were treated with percutaneous osteoplasty for painful extraspinal bone lesions resistant to NSAID therapy or treated with opioids.Results: Technical success was achieved in all cases. Mean visual analog pain score (VAS) scores dropped from 8.4 ± 1 (range 6-10; pretreatment) to 2.1 ± 1.7 (range 0-7; 24-h posttreatment). Pain completely disappeared in six (15%) patients. Administration of analgesics was suspended in 16 (41%) patients whereas in 17 (43.5%) patients previously treated with opioids, residual pain was controlled by NSAIDs. In six (15%) patients, narcotics administration was continued due to the persistence of pain. All patients completed an at least 6-month follow-up with a median long-term VAS score of 2.4 ± 2.1 (range 0-9). In five (13%) patients, pain remission was complete, with no recurrence at 18 months from treatment.Conclusion: Our study suggests that PO may be feasible, effective, and safe in the treatment of conventional therapy-resistant extraspinal painful multiple myeloma lesions providing long-lasting pain relief with occasional tumor control and a significant reduction in the assumption of analgesic drugs. [ABSTRACT FROM AUTHOR]

Background: Percutaneous vertebroplasty is currently an alternative for treating vertebral fractures of the thoracic and lumbar spine, providing both pain control and vertebral stabilization. In the cervical spine, however, percutaneous vertebroplasty is technically challenging because of the complex anatomy of this region. Questions/purposes: We evaluated the technical feasibility, complication rate, and ability of percutaneous vertebroplasty to provide pain relief in patients with painful metastatic cervical fractures. Methods: We retrospectively reviewed 62 patients (24 men) who, between May 2005 and May 2009, underwent vertebroplasty to treat painful metastatic cervical fractures. Each patient was evaluated by a visual analog scale for pain, number of pain analgesics, and CT and MRI before, the day after, and at 3 months after the procedure. Results: Two of the 62 patients had asymptomatic cement leakage in the soft tissues. We observed no delayed complications. Mean pretreatment and 24-hour posttreatment visual analog scale pain scores were 7.9 ± 1.7 and 1.5 ± 2, respectively. Immediately after surgery, the pain completely disappeared in 25 (40%) patients. Administration of analgesics was suspended in 34 (55%) patients whereas in 27 (39%) patients the median analgesics use decreased from two pills per day (range, 0-3) to 0 (range, 0-3). In two (3%) patients, analgesics administration was continued due to the persistence of pain. At 3 months, the patients reported a mean visual analog scale pain score of 1.7 ± 2. Conclusions: Our data suggest, in selected patients, percutaneous vertebroplasty may be performed with a high technical success rate combined with a low complication rate, providing immediate pain relief lasting at least 3 months and a reduction in the use of analgesic drugs. Level of Evidence: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Quantitative molecular imaging with PET can offer insights into physiologic and pathologic processes and is widely used for studying brain disorders. The NeuroEXPLORER is a recently developed dedicated brain PET system offering high spatial resolution and high sensitivity with an extended axial length. This study evaluated the quantitative precision and accuracy of the NeuroEXPLORER with phantom and human data for a variety of imaging conditions that are relevant to dynamic neuroimaging studies. Methods: Thirty-minute scans of an image quality (IQ) phantom and a 3-dimensional Hoffman brain phantom filled with [ 18 F]FDG were performed over 13 h, covering phantom activities of 1.3-177 MBq. Furthermore, a uniform cylindric phantom filled with 558 MBq of 11 C was scanned for 4 h. Quantitative accuracy was assessed using the contrast recovery coefficient (CRC), background variability, and background bias in the IQ phantom, the recovery coefficients (RCs) in the Hoffman phantom, and the bias in the uniform phantom. Results were compared at delayed time points, with different reconstruction parameters and frame lengths down to 1 s. Moreover, randomly subsampled frames of 2 imaging time points (0-2 min and 60-90 min) from a dynamic scan of a healthy volunteer with a 177-MBq injected dose of ( R )-4-(3-fluoro-5-(fluoro- 18 F)phenyl)-1-((3-methylpyridin-4-yl)methyl)pyrrolidin-2-one ([ 18 F]SynVesT-1) were used to assess quantification of brain uptake and image-derived input function extraction. Results: Negligible effects were observed on CRC and background bias with 3-177 MBq in the IQ phantom, and bias was less than 5% with 1-558 MBq in the uniform phantom. RC variations were within ±1% with 2-169 MBq in the Hoffman phantom, showcasing the system's high spatial resolution and high sensitivity. Short-frame reconstructions of the 60- to 90-min healthy-volunteer scan showed a ±1% mean difference in quantification of brain uptake for frame lengths down to 30 s and demonstrated the feasibility of measuring image-derived input function with mean absolute differences below 10% for frame lengths down to 1 s. Conclusion: The NeuroEXPLORER, with its high detection sensitivity, maintains high precision and accuracy across a wide range of imaging conditions beyond those evaluated in standard performance tests. These results demonstrate its potential for quantitative neuroimaging applications., (© 2024 by the Society of Nuclear Medicine and Molecular Imaging.)

Purpose: This study evaluates the potential of within-individual Metabolic Connectivity (wi-MC), from dynamic [ 18 F]FDG PET data, based on the Euclidean Similarity method. This approach leverages the biological information of the tracer's full temporal dynamics, enabling the direct extraction of individual metabolic connectomes. Specifically, the proposed framework, applied to glioma pathology, seeks to assess sensitivity to metabolic dysfunctions in the whole brain, while simultaneously providing further insights into the pathophysiological mechanisms regulating glioma progression., Methods: We designed an index (Distance from Healthy Group, DfHG) based on the alteration of wi-MC in each patient (n = 44) compared to a healthy reference (from 57 healthy controls), to individually quantify metabolic connectivity abnormalities, resulting in an Impairment Map highlighting significantly compromised areas. We then assessed whether our measure of metabolic network alteration is associated with well-established markers of disease severity (tumor grade and volume, with and without edema). Subsequently, we investigated disruptions in wi-MC homotopic connectivity, assessing both affected and seemingly healthy tissue to deepen the pathology's impact on neural communication. Finally, we compared network impairments with local metabolic alterations determined from SUVR, a validated diagnostic tool in clinical practice., Results: Our framework revealed how gliomas cause extensive alterations in the topography of brain networks, even in structurally unaffected regions outside the lesion area, with a significant reduction in connectivity between contralateral homologous regions. High-grade gliomas have a stronger impact on brain networks, and edema plays a mediating role in global metabolic alterations. As compared to the conventional SUVR-based analysis, our approach offers a more holistic view of the disease burden in individual patients, providing interesting additional insights into glioma-related alterations., Conclusion: Considering our results, individual PET connectivity estimates could hold significant clinical value, potentially allowing the identification of new prognostic factors and personalized treatment in gliomas or other focal pathologies., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The brain's resting-state energy consumption is expected to be mainly driven by spontaneous activity. In our previous work, we extracted a wide range of features from resting-state fMRI (rs-fMRI), and used them to predict [ 18 F]FDG PET SUVR as a proxy of glucose metabolism. Here, we expanded upon our previous effort by estimating [ 18 F]FDG kinetic parameters according to Sokoloff's model, i.e., K i (irreversible uptake rate), K 1 (delivery), k 3 (phosphorylation), in a large healthy control group. The parameters' spatial distribution was described at a high spatial resolution. We showed that while K 1 is the least redundant, there are relevant differences between K i and k 3 (occipital cortices, cerebellum and thalamus). Using multilevel modeling, we investigated how much of the regional variability of [ 18 F]FDG parameters could be explained by a combination of rs-fMRI variables only, or with the addition of cerebral blood flow (CBF) and metabolic rate of oxygen (CMRO 2 ), estimated from 15 O PET data. We found that combining rs-fMRI and CMRO 2 led to satisfactory prediction of individual K i variance (45%). Although more difficult to describe, K i and k 3 were both most sensitive to local rs-fMRI variables, while K 1 was sensitive to CMRO 2 . This work represents the most comprehensive assessment to date of the complex functional and metabolic underpinnings of brain glucose consumption., Competing Interests: Declaration of conflicting interests The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background and Purpose: Frontotemporal dementia (FTD) is a clinically and pathologically heterogeneous neurodegenerative condition with a prevalence comparable to Alzheimer's disease for patients under 65 years of age. Limited studies have examined the association between cognition and neuroimaging in FTD using different imaging modalities., Methods: We examined the association of cognition using Montreal Cognitive Assessment (MoCA) with both gray matter (GM) volume and glucose metabolism using magnetic resonance imaging and fluorodeoxyglucose (FDG)-PET in 21 patients diagnosed with FTD. Standardized uptake value ratio (SUVR) using the brainstem as a reference region was the primary outcome measure for FDG-PET. Partial volume correction was applied to PET data to account for disease-related atrophy., Results: Significant positive associations were found between whole-cortex GM volume and MoCA scores (r = 0.46, p = .04). The association between whole-cortex FDG SUVR and MoCA scores was not significant (r = 0.37, p = .09). GM volumes of the frontal cortex (r = 0.54, p = .01), caudate (r = 0.62, p<.01), and insula (r = 0.57, p<.01) were also significantly correlated with MoCA, as were SUVR values of the insula (r = 0.51, p = .02), thalamus (r = 0.48, p = .03), and posterior cingulate cortex (PCC) (r = 0.47, p = .03)., Conclusions: Whole-cortex atrophy is associated with cognitive dysfunction, and this association is larger than for whole-cortex hypometabolism as measured with FDG-PET. At the regional level, focal atrophy and/or hypometabolism in the frontal cortex, insula, PCC, thalamus, and caudate seem to be important for the decline of cognitive function in FTD. Furthermore, these results highlight how functional and structural changes may not overlap and might contribute to cognitive dysfunction in FTD in different ways., (© 2024 American Society of Neuroimaging.)

The collaboration of Yale, the University of California, Davis, and United Imaging Healthcare has successfully developed the NeuroEXPLORER, a dedicated human brain PET imager with high spatial resolution, high sensitivity, and a built-in 3-dimensional camera for markerless continuous motion tracking. It has high depth-of-interaction and time-of-flight resolutions, along with a 52.4-cm transverse field of view (FOV) and an extended axial FOV (49.5 cm) to enhance sensitivity. Here, we present the physical characterization, performance evaluation, and first human images of the NeuroEXPLORER. Methods: Measurements of spatial resolution, sensitivity, count rate performance, energy and timing resolution, and image quality were performed adhering to the National Electrical Manufacturers Association (NEMA) NU 2-2018 standard. The system's performance was demonstrated through imaging studies of the Hoffman 3-dimensional brain phantom and the mini-Derenzo phantom. Initial 18 F-FDG images from a healthy volunteer are presented. Results: With filtered backprojection reconstruction, the radial and tangential spatial resolutions (full width at half maximum) averaged 1.64, 2.06, and 2.51 mm, with axial resolutions of 2.73, 2.89, and 2.93 mm for radial offsets of 1, 10, and 20 cm, respectively. The average time-of-flight resolution was 236 ps, and the energy resolution was 10.5%. NEMA sensitivities were 46.0 and 47.6 kcps/MBq at the center and 10-cm offset, respectively. A sensitivity of 11.8% was achieved at the FOV center. The peak noise-equivalent count rate was 1.31 Mcps at 58.0 kBq/mL, and the scatter fraction at 5.3 kBq/mL was 36.5%. The maximum count rate error at the peak noise-equivalent count rate was less than 5%. At 3 iterations, the NEMA image-quality contrast recovery coefficients varied from 74.5% (10-mm sphere) to 92.6% (37-mm sphere), and background variability ranged from 3.1% to 1.4% at a contrast of 4.0:1. An example human brain 18 F-FDG image exhibited very high resolution, capturing intricate details in the cortex and subcortical structures. Conclusion: The NeuroEXPLORER offers high sensitivity and high spatial resolution. With its long axial length, it also enables high-quality spinal cord imaging and image-derived input functions from the carotid arteries. These performance enhancements will substantially broaden the range of human brain PET paradigms, protocols, and thereby clinical research applications., (© 2024 by the Society of Nuclear Medicine and Molecular Imaging.)

Brain glucose metabolism, which can be investigated at the macroscale level with [ 18 F]FDG PET, displays significant regional variability for reasons that remain unclear. Some of the functional drivers behind this heterogeneity may be captured by resting-state functional magnetic resonance imaging (rs-fMRI). However, the full extent to which an fMRI-based description of the brain's spontaneous activity can describe local metabolism is unknown. Here, using two multimodal datasets of healthy participants, we built a multivariable multilevel model of functional-metabolic associations, assessing multiple functional features, describing the 1) rs-fMRI signal, 2) hemodynamic response, 3) static and 4) time-varying functional connectivity, as predictors of the human brain's metabolic architecture. The full model was trained on one dataset and tested on the other to assess its reproducibility. We found that functional-metabolic spatial coupling is nonlinear and heterogeneous across the brain, and that local measures of rs-fMRI activity and synchrony are more tightly coupled to local metabolism. In the testing dataset, the degree of functional-metabolic spatial coupling was also related to peripheral metabolism. Overall, although a significant proportion of regional metabolic variability can be described by measures of spontaneous activity, additional efforts are needed to explain the remaining variance in the brain's 'dark energy'., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: The need for arterial blood data in quantitative PET research limits the wider usability of this imaging method in clinical research settings. Image-derived input function (IDIF) approaches have been proposed as a cost-effective and non-invasive alternative to gold-standard arterial sampling. However, this approach comes with its own limitations-partial volume effects and radiometabolite correction among the most important-and varying rates of success, and the use of IDIF for brain PET has been particularly troublesome., Main Body: This paper summarizes the limitations of IDIF methods for quantitative PET imaging and discusses some of the advances that may make IDIF extraction more reliable. The introduction of automated pipelines (both commercial and open-source) for clinical PET scanners is discussed as a way to improve the reliability of IDIF approaches and their utility for quantitative purposes. Survey data gathered from the PET community are then presented to understand whether the field's opinion of the usefulness and validity of IDIF is improving. Finally, as the introduction of next-generation PET scanners with long axial fields of view, ultra-high sensitivity, and improved spatial and temporal resolution, has also brought IDIF methods back into the spotlight, a discussion of the possibilities offered by these state-of-the-art scanners-inclusion of large vessels, less partial volume in small vessels, better description of the full IDIF kinetics, whole-body modeling of radiometabolite production-is included, providing a pathway for future use of IDIF., Conclusion: Improvements in PET scanner technology and software for automated IDIF extraction may allow to solve some of the major limitations associated with IDIF, such as partial volume effects and poor temporal sampling, with the exciting potential for accurate estimation of single kinetic rates. Nevertheless, until individualized radiometabolite correction can be performed effectively, IDIF approaches remain confined at best to a few tracers., (© 2023. The Author(s).)

Metabolic connectivity (MC) has been previously proposed as the covariation of static [ 18 F]FDG PET images across participants, i.e., across-individual MC (ai-MC). In few cases, MC has been inferred from dynamic [ 18 F]FDG signals, i.e., within-individual MC (wi-MC), as for resting-state fMRI functional connectivity (FC). The validity and interpretability of both approaches is an important open issue. Here we reassess this topic, aiming to 1) develop a novel wi-MC methodology; 2) compare ai-MC maps from standardized uptake value ratio ( SUVR ) vs. [ 18 F]FDG kinetic parameters fully describing the tracer behavior (i.e., K i , K 1 , k 3 ); 3) assess MC interpretability in comparison to structural connectivity and FC. We developed a new approach based on Euclidean distance to calculate wi-MC from PET time-activity curves. The across-individual correlation of SUVR , K i , K 1 , k 3 produced different networks depending on the chosen [ 18 F]FDG parameter ( k 3 MC vs. SUVR MC, r = 0.44). We found that wi-MC and ai-MC matrices are dissimilar (maximum r = 0.37), and that the match with FC is higher for wi-MC (Dice similarity: 0.47-0.63) than for ai-MC (0.24-0.39). Our analyses demonstrate that calculating individual-level MC from dynamic PET is feasible and yields interpretable matrices that bear similarity to fMRI FC measures., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

The Neotropical region hosts 4225 freshwater fish species, ranking first among the world's most diverse regions for freshwater fishes. Our NEOTROPICAL FRESHWATER FISHES data set is the first to produce a large-scale Neotropical freshwater fish inventory, covering the entire Neotropical region from Mexico and the Caribbean in the north to the southern limits in Argentina, Paraguay, Chile, and Uruguay. We compiled 185,787 distribution records, with unique georeferenced coordinates, for the 4225 species, represented by occurrence and abundance data. The number of species for the most numerous orders are as follows: Characiformes (1289), Siluriformes (1384), Cichliformes (354), Cyprinodontiformes (245), and Gymnotiformes (135). The most recorded species was the characid Astyanax fasciatus (4696 records). We registered 116,802 distribution records for native species, compared to 1802 distribution records for nonnative species. The main aim of the NEOTROPICAL FRESHWATER FISHES data set was to make these occurrence and abundance data accessible for international researchers to develop ecological and macroecological studies, from local to regional scales, with focal fish species, families, or orders. We anticipate that the NEOTROPICAL FRESHWATER FISHES data set will be valuable for studies on a wide range of ecological processes, such as trophic cascades, fishery pressure, the effects of habitat loss and fragmentation, and the impacts of species invasion and climate change. There are no copyright restrictions on the data, and please cite this data paper when using the data in publications., (© 2022 The Ecological Society of America.)

Introduction: Resting-state network (RSN) connectivity is a widely used measure of the brain's functional organization in health and disease; however, little is known regarding the underlying neurophysiology of RSNs. The aim of the current study was to investigate associations between RSN connectivity and synaptic density assessed using the synaptic vesicle glycoprotein 2A radioligand 11 C-UCB-J PET. Methods: Independent component analyses (ICA) were performed on resting-state fMRI and PET data from 34 healthy adult participants (16F, mean age: 46 ± 15 years) to identify a priori RSNs of interest (default-mode, right frontoparietal executive-control, salience, and sensorimotor networks) and select sources of 11 C-UCB-J variability (medial prefrontal, striatal, and medial parietal). Pairwise correlations were performed to examine potential intermodal associations between the fractional amplitude of low-frequency fluctuations (fALFF) of RSNs and subject loadings of 11 C-UCB-J source networks both locally and along known anatomical and functional pathways. Results: Greater medial prefrontal synaptic density was associated with greater fALFF of the anterior default-mode, posterior default-mode, and executive-control networks. Greater striatal synaptic density was associated with greater fALFF of the anterior default-mode and salience networks. Post-hoc mediation analyses exploring relationships between aging, synaptic density, and RSN activity revealed a significant indirect effect of greater age on fALFF of the anterior default-mode network mediated by the medial prefrontal 11 C-UCB-J source. Discussion: RSN functional connectivity may be linked to synaptic architecture through multiple local and circuit-based associations. Findings regarding healthy aging, lower prefrontal synaptic density, and lower default-mode activity provide initial evidence of a neurophysiological link between RSN activity and local synaptic density, which may have relevance in neurodegenerative and psychiatric disorders., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Fang, Volpi, Holmes, Esterlis, Carson and Worhunsky.)

The brain consumes the most energy per relative mass amongst the organs in the human body. Theoretical and empirical studies have shown that behavioral processes are relatively inexpensive metabolically, and that most energy goes to maintaining the status quo, i.e., the balance of cell membranes' resting potentials and subthreshold spontaneous activity. Spontaneous activity fluctuates across brain regions in a correlated fashion that defines multi-scale hierarchical networks called resting-state networks (RSNs). Different regions of the brain display different metabolic consumption, but the relationship between regional brain metabolism and RSNs is still under investigation. Here, we examine the variability of glucose metabolism across brain regions, measured with the relative standard uptake value (SUVR) using 18 F-FDG PET, and the topology of RSNs, measured through graph analysis applied to fMRI resting-state functional connectivity (FC). We found a moderate linear relationship between the strength (STR) of pairwise regional FC and metabolism. Moreover, the linear correlation between SUVR and STR grew stronger as we considered more connected regions (hubs). Regions connecting different RSNs, or connector hubs, showed higher SUVR than regions connecting nodes within the same RSN, or provincial hubs. Our results show that functional connections as probed by fMRI are related to glucose metabolism, especially in a system of provincial and connector hubs., Competing Interests: Declaration of Competing Interest None., (Copyright © 2022. Published by Elsevier Inc.)

Quantification of brain [ 18 F] fluorodeoxyglucose ([ 18 F]FDG) positron emission tomography (PET) data requires an input function. A noninvasive alternative to gold-standard arterial sampling is the image-derived input function (IDIF), typically extracted from the internal carotid arteries (ICAs), which are however difficult to segment and subjected to spillover effects. In this work, we evaluated the feasibility of extracting the IDIF from two different vascular sites, i.e., 1) common carotids (CCA) and 2) superior sagittal sinus (SSS), other than 3) ICA in a large group of glioma patients undergoing a dynamic [ 18 F]FDG PET acquisition on a hybrid PET/MR scanner. Comparisons are drawn between the different IDIFs in terms of peak amplitude and shape, as well as between the estimates of fractional uptake rate (Kr) obtained from the different extraction sites in terms of a) grey/white matter average absolute values, b) ratio of grey-to-white matter, and c) spatial patterns for the hemisphere contralateral to the lesion. Clinical Relevance - This work points towards new feasible IDIF extraction sites (CCA in particular) which could allow for fully noninvasive absolute PET quantification in clinical populations.

The gold-standard approach to quantifying dynamic PET images relies on using invasive measures of the arterial plasma tracer concentration. An attractive alternative is to employ an image-derived input function (IDIF), corrected for spillover effects and rescaled with venous plasma samples. However, venous samples are not always available for every participant. In this work, we used the nonlinear mixed-effects modeling approach to develop a model which infers venous tracer kinetics by using venous samples obtained from a population of healthy individuals and integrating subject-specific covariates. Population parameters (fixed effects), their between-subject variability (random effects), and the effects of covariates were estimated. The selected model will allow to reliably infer venous tracer kinetics in subjects with missing measurements. Clinical relevance - The derived model will be relevant for fully noninvasive dynamic FDG PET quantification using image-derived input functions in both healthy and patient populations when hemodynamics is not impaired.

Metabolic connectivity is conventionally calculated in terms of correlation of static positron emission tomography (PET) measurements across subjects. There is increasing interest in deriving metabolic connectivity at the single-subject level from dynamic PET data, in a similar way to functional magnetic resonance imaging. However, the strong multicollinearity among region-wise PET time-activity curves (TACs), their non-Gaussian distribution, and the choice of the best strategy for TAC standardization before metabolic connectivity estimation, are non-trivial methodological issues to be tackled.In this work we test four different approaches to estimate sparse inverse covariance matrices, as well as three similarity-based methods to derive adjacency matrices. These approaches, combined with three different TAC standardization strategies, are employed to quantify metabolic connectivity from dynamic [ 18 F]fluorodeoxyglucose ([ 18 F]FDG) PET data in four healthy subjects.

This paper reports on a new species of Trichomycterus from the Rio Doce basin. Unusually for new taxa in the genus during the past few decades, the new species is not narrowly endemic but instead widely distributed in its major drainage, the Rio Doce. The species has been collected and deposited in scientific collections for some years, but has been systematically misidentified as the more abundant Trichomycterus immaculatus or, to a lesser degree, as other morphologically similar species from south-eastern Brazil such as T. nigricans and T. pradensis. A combination of several morphological characteristics, such as vertebral number, pectoral-fin ray counts, pigmentation pattern and barcoding distance, were iteratively used and unambiguously distinguish the new species from all congeners. The present case reveals a pattern of diversity-discovery in which rare and narrowly endemic morphologically conspicuous species are discovered and described before visually inconspicuous taxa, even when the latter are more abundant and widespread. The morphological similarities among south-eastern Brazilian species with a uniform dark-grey color serve as basis for a brief discussion about the concepts of cryptic and pseudo-cryptic species in Trichomycterus and their consequences for potentially hidden diversity in the genus., (© 2020 Fisheries Society of the British Isles.)

Purpose: To assess the efficacy and safety of the Outback device in patients with a chronic total occlusion (CTO) of the superficial femoral artery and evaluate its impact on fluoroscopy and procedural times., Materials and Methods: From October 2006 to March 2007, 52 patients affected by TASC II-D superficial femoral artery CTO were treated with subintimal recanalization. Clinical indications for endovascular recanalization were: claudication, tissue loss, and at rest leg pain with critical limb ischemia. In 26 patients the manual reentry technique was used and in 26 the OUTBACK(®) LTD Re-Entry Catheter was used. Total procedure time, fluoroscopy time and precision in targeting the expected reentry site have been compared., Results: Technical success was achieved in all cases (100%). In group 2, the planned in-target re-entry was achieved in 11/26 cases (42.3%). The procedure was performed with a traditional antegrade approach in 23/26 (88.4%) cases and in three cases (11.6%) a combined antegrade/retrograde approach was necessary. In group 1, the in-target re-entry was achieved in 26/26 cases (100%). In group 2, the mean procedural time was 55.4 ± 14.2 min with a mean fluoroscopy time 39.6 ± 13.9 min compared to 36.0 ± 9.4 min and 29.8 ± 8.9 min, respectively, of group 1 (P < 0.0001)., Conclusions: In our experience, the use of this device is very useful for the revascularization of chronic femoral occlusions, even calcific, in which an accurate re-entry cannot be achieved with the conventional subintimal technique. In these cases, the Outback device grants high technical success rates and a significant reduction of procedural and fluoroscopy times., (Copyright © 2013 Wiley Periodicals, Inc.)

Objective: This study was designed to evaluate the feasibility of the implantation of a new interspinous device (Falena) in patients with lumbar spinal stenosis. The clinical outcomes and imaging results were assessed by orthostatic MR during an up to 6-month follow-up period., Methods: Between October 2008 and February 2010, the Falena was implanted at a single level in 26 patients (17 men; mean age, 69 (range, 54-82) years) who were affected by degenerative lumbar spinal stenosis. All of the patients were clinically evaluated before the procedure and at 1 and 3 months. Furthermore, 20 patients have completed a 6-month follow-up. Pain was assessed before and after the intervention using the Visual Analogue Scale score and the Oswestry Disability Index questionnaire. Orthostatic MR imaging was performed before the implantation and at 3 months to assess the correlation with the clinical outcome., Results: The mean ODI score decreased from 48.9 before the device implantation to 31.2 at 1 month (p < 0.0001). The mean VAS score decreased from 7.6 before to 3.9 (p < 0.0001) at 1 month and 3.6 at 3 months after the procedure (p = 0.0115). These values were stable at 6 months evaluation. No postimplantation major complications were recorded. MRI evaluation documented in most cases an increased size of the spinal canal area. Similarly a bilateral foraminal area improvement was found. The variation of the intervertebral space height measured on the posterior wall was not significant., Conclusions: In our preliminary experience with the Falena in a small cohort of patients, we obtained clinical and imaging results aligned to those reported with similar interspinous devices.

Aim: The aim of this study was to assess the feasibility, safety and efficacy of percutaneous transluminal angioplasty (PTA) in patients with critical limb ischemia (CLI) using a novel balloon designed for below-the-knee (BTK) indications., Methods: The authors have prospectively collected baseline, periprocedural and mid-term data of all consecutive patients with CLI due to BTK disease in which PTA was attempted using a long (210 mm), conically-shaped balloon (0.5 mm tapering from proximal to distal balloon edges). The primary objective was the assessment of acute success (composite of technical, angiographic and procedural success). The secondary assessments included limb salvage rate, major (above the ankle) and minor (below the ankle) amputation, change in Rutherford class and cutaneous oxygen tension, reocclusion/restenosis, rehospitalization, and repeat revascularization after one year., Results: A total of 31 patients were treated with 36 long tapered balloons. Ten patients presented with ischemic tissue loss. Target lesions were mostly occlusive and diffuse, commonly involving the tibial arteries as well as the in-flow and out-flow vessels. Acute success was achieved in 100% of the cases without periprocedural complications. Clinical improvement in functional status was obtained and maintained after an average of 12 months, with a significant (P<0.001) decrease in Rutherford class, 100% limb salvage, no major amputation and five (16.1%) minor amputations. Duplex ultrasound control showed restenosis/reocclusion in two (6.5%) cases, whereas a total of seven (22.6%) patients underwent repeat revascularization (2 [6.5%] target lesion re-PTA)., Conclusions: Infra-popliteal PTA with this new, BTK dedicated, long tapered balloon in patients with CLI was feasible and safe, and was associated favorable clinical results at both acute and mid-term follow-up.

Purpose: To assess the safety and efficacy of a device for vibrational angioplasty in the percutaneous intraluminal recanalization of long infrainguinal chronic total occlusions (CTO)., Technique: The Crosser CTO Recanalization System is a mechanical recanalization device that uses high-frequency vibrational energy to disrupt and channel through fibrocalcific plaque without harming the vessel wall, thus assisting in the recanalization of an occluded artery. In 12 diabetic patients (7 men; median age 71 years, range 58-80) with critical limb ischemia owing to long (median length 26 cm, range 21-32) infrainguinal CTOs resistant to conventional guidewire techniques, the Crosser CTO Recanalization System was successful in intraluminally crossing the occlusion in 9 (75%) patients in <5 minutes (mean 4:03 minutes). The safety endpoint (distal lumen guidewire position with no vessel perforation or dissection) was achieved in all successful cases., Conclusion: In our preliminary experience, the Crosser CTO Recanalization Catheter decreased crossing time, was safe, and achieved a high rate of intraluminal recanalization of long infrainguinal CTOs.