Functional Imaging Methods Research Articles

More restriction, more overeating: conflict monitoring ability is impaired by food-thought suppression among restrained eaters.

Numerous studies have shown that restrained eating is not an effective weight loss strategy. Restrained eaters often suppress their desires and thoughts about tasty food, which makes it more difficult to control themselves in subsequent eating behavior. The ego depletion impairs conflict monitoring abilities. Therefore, this study explored the effects of food thoughts suppression on restrained eaters' conflict monitoring. Therefore, this study used functional magnetic resonance imaging (fMRI) methods to explore changes in the activity of brain regions involved in conflict monitoring when restrained eaters choose between high- and low-calorie foods after either suppressing or not suppressing thoughts about food. The results showed that, compared to the control condition, after suppression of such thoughts, restrained eaters chose more high-calorie foods and displayed decreased activity in the dorsal anterior cingulate cortex-an important region in charge of conflict monitoring. At the same time, the functional coupling of the dorsal anterior cingulate cortex and the precuneus increased. Our findings suggest that restrained eaters' suppression of thoughts about tasty food could lead to a decline in their ability to monitor conflicts between current behaviors and goals, which in turn leads to unhealthy eating behavior.

Axon hillock currents enable single-neuron-resolved 3D reconstruction using diamond nitrogen-vacancy magnetometry

Sensing neuronal action potential associated magnetic fields (APMFs) is an emerging viable alternative of functional brain mapping. Measurement of APMFs of large axons of worms have been possible due to their size. In the mammalian brain, axon sizes, their numbers and routes, restricts using such functional imaging methods. With a segmented model of mammalian pyramidal neurons, we show that the APMF of intra-axonal currents in the axon hillock are two orders of magnitude larger than other neuronal locations. Expected 2D magnetic field maps of naturalistic spiking activity of a volume of neurons via widefield diamond-nitrogen-vacancy-center-magnetometry were simulated. A dictionary-based matching pursuit type algorithm applied to the data using the axon-hillock’s APMF signature allowed spatiotemporal reconstruction of action potentials in the volume of brain tissue at single cell resolution. Enhancement of APMF signals coupled with magnetometry advances thus can potentially replace current functional brain mapping techniques.

Optimizing Use of Neuroimaging Tools in Evaluation of Prodromal Alzheimer's Disease and Related Disorders.

Alzheimer's disease (AD) is the most common neurodegenerative disease and is characterized by preclinical, pre-dementia, and dementia phases. Progression of the disease leads to cognitive decline and is associated with loss of functional independence, personality changes, and behavioral disturbances. Current guidelines for AD diagnosis include the use of neuroimaging tools as biomarkers for identifying and monitoring pathological changes. Various imaging modalities, namely magnetic resonance imaging (MRI), fluorodeoxyglucose-positron emission tomography (FDG-PET) and PET with amyloid-beta tracers are available to facilitate early accurate diagnoses. Enhancing diagnosis in the early stages of the disease can allow for timely interventions that can delay progression of the disease. This paper will discuss the characteristic findings associated with each of the imaging tools for patients with AD, with a focus on FDG-PET due to its established accuracy in assisting with the differential diagnosis of dementia and discussion of other methods including MRI. Diagnostically-relevant features to aid clinicians in making a differential diagnosis will also be pointed out and multimodal imaging will be reviewed. We also discuss the role of quantification software in interpretation of brain imaging. Lastly, to guide evaluation of patients presenting with cognitive deficits, an algorithm for optimal integration of these imaging tools will be shared. Molecular imaging modalities used in dementia evaluations hold promise toward identifying AD-related pathology before symptoms are fully in evidence. The work describes state of the art functional and molecular imaging methods for AD. It will also overview a clinically applicable quantitative method for reproducible assessments of such scans in the early identification of AD.

Tissue dynamics spectroscopic imaging: functional imaging of heterogeneous cancer tissue.

.Significance: Tumor heterogeneity poses a challenge for the chemotherapeutic treatment of cancer. Tissue dynamics spectroscopy captures dynamic contrast and can capture the response of living tissue to applied therapeutics, but the current analysis averages over the complicated spatial response of living biopsy samples.Aim: To develop tissue dynamics spectroscopic imaging (TDSI) to map the heterogeneous spatial response of tumor tissue to anticancer drugs.Approach: TDSI is applied to tumor spheroids grown from cell lines and to ex vivo living esophageal biopsy samples. Doppler fluctuation spectroscopy is performed on a voxel basis to extract spatial maps of biodynamic biomarkers. Functional images and bivariate spatial maps are produced using a bivariate color merge to represent the spatial distribution of pairs of signed drug-response biodynamic biomarkers.Results: We have mapped the spatial variability of drug responses within biopsies and have tracked sample-to-sample variability. Sample heterogeneity observed in the biodynamic maps is associated with histological heterogeneity observed using inverted selective-plane illumination microscopy.Conclusion: We have demonstrated the utility of TDSI as a functional imaging method to measure tumor heterogeneity and its potential for use in drug-response profiling.

Dynamic analysis of fMRI activation during epileptic spikes can help identify the seizure origin.

We use the dynamic electroencephalography-functional magnetic resonance imaging (EEG-fMRI) method to incorporate variability in the amplitude and field of the interictal epileptic discharges (IEDs) into the fMRI analysis. We ask whether IED variability analysis can (a) identify additional activated brain regions during the course of IEDs, not seen in standard analysis; and (b) demonstrate the origin and spread of epileptic activity. We explore whether these functional changes recapitulate the structural connections and propagation of epileptic activity during seizures. Seventeen patients with focal epilepsy and at least 30 IEDs of a single type during simultaneous EEG-fMRI were studied. IED variability and EEG source imaging (ESI) analysis extracted time-varying dynamic changes. General linear modeling (GLM) generated static functional maps. Dynamic maps were compared to static functional maps. The dynamic sequence from IED variability was compared to the ESI results. In a subset of patients, we investigated structural connections between active brain regions using diffusion-based fiber tractography. IED variability distinguished the origin of epileptic activity from its propagation in 15 of 17 (88%) patients. This included two cases where no result was obtained from the standard GLM analysis. In both of these cases, IED variability revealed activation in line with the presumed epileptic focus. Two cases showed no result from either method. Both had very high spike rates associated with dysplasia in the postcentral gyrus. In all 15 cases with dynamic activation, the observed dynamics were concordant with ESI. Fiber tractography identified specific white matter pathways between brain regions that were active at IED onset and propagation. Dynamic techniques involving IED variability can provide additional power for EEG-fMRI analysis, compared to standard analysis, revealing additional biologically plausible information in cases with no result from the standard analysis and gives insight into the origin and spread of IEDs.

Assessing Response to Therapy in Neuroblastoma with MRI T1 Mapping.

HomeRadiology: Imaging CancerVol. 2, No. 5 Previous Research HighlightsFree AccessAssessing Response to Therapy in Neuroblastoma with MRI T1 MappingGary D. LukerGary D. LukerGary D. LukerPublished Online:Sep 25 2020https://doi.org/10.1148/rycan.2020209026MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In Take-Away Points■ Major Focus: Investigating T1 mapping as a quantitative, functional MRI marker for response to targeted therapy in neuroblastoma.■ Key Result: Regions with high T1 corresponded with undifferentiated neuroblasts, which decreased with successful therapy.■ Impact: Clinical translation of T1 mapping may help improve precision medicine for children with neuroblastoma and other malignancies with similar pathologic features.Neuroblastoma is a childhood malignancy that arises from neural crest cells in the sympathetic nervous system. Amplification of the gene MYCN, the most common genetic abnormality in this cancer, marks patients with aggressive disease and poor prognosis. Trials with drugs designed to destabilize MYCN protein require functional imaging methods to measure response to therapy earlier and with greater sensitivity than changes in tumor volume. Imaging cell membrane transporters for norepinephrine or metabolism with metaiodobenzylguanidine (MIBG) or fluorine-18 2-fluoro-2-deoxyglucose PET/CT, respectively, provide functional information but expose children to additional radiation and imaging studies. Since the soft-tissue delineation of MRI makes it the preferred method for anatomic imaging of neuroblastoma, an MRI-based functional imaging method would streamline evaluation.Using a genetically engineered mouse model of MYCN neuroblastoma, Zormpas-Petridis et al discovered that T1 mapping from MRI detects tumor heterogeneity. Regions with high and low T1 signal corresponded to areas in tumors with large numbers of undifferentiated neuroblasts and more differentiated cancer cells, respectively. Treatment with targeted inhibitors against aurora A kinase (alisertib) or mTOR (vistusertib) reduced T1 signal due to death of undifferentiated neuroblasts. The authors proposed that undifferentiated neuroblasts produce high T1 signal because these cells have very large nuclei and minimal cytoplasm, similar to other “small round blue cell tumors” including medulloblastoma, Ewing sarcoma, and small cell lung cancer. These data support clinical trials using T1 mapping to monitor response to targeted therapies in neuroblastoma and suggest this MRI method may extend to other tumors in the group of small round blue cell tumors.Highlighted ArticleZormpas-Petridis K, Poon E, Clarke M, et al. Noninvasive MRI native T1 mapping detects response to MYCN-targeted therapies in the Th-MYCN model of neuroblastoma. Cancer Res 2020;80:3424–3435. doi: 10.1158/0008-5472.CAN-20-0133.Highlighted ArticleZormpas-Petridis K, Poon E, Clarke M, et al. Noninvasive MRI native T1 mapping detects response to MYCN-targeted therapies in the Th-MYCN model of neuroblastoma. Cancer Res 2020;80:3424–3435. doi: 10.1158/0008-5472.CAN-20-0133. Crossref, Medline, Google ScholarArticle HistoryPublished online: Sept 25 2020 FiguresReferencesRelatedDetailsRecommended Articles Updates in Diagnosis, Management, and Treatment of NeuroblastomaRadioGraphics2018Volume: 38Issue: 2pp. 566-580Extraskeletal Ewing Sarcoma from Head to Toe: Multimodality Imaging ReviewRadioGraphics2022Volume: 42Issue: 4pp. 1145-1160Current and Emerging Roles of Whole-Body MRI in Evaluation of Pediatric Cancer PatientsRadioGraphics2019Volume: 39Issue: 2pp. 516-534Pediatric Brain Tumor Genetics: What Radiologists Need to KnowRadioGraphics2018Volume: 38Issue: 7pp. 2102-2122MIBG in Neuroblastoma Diagnostic Imaging and TherapyRadioGraphics2016Volume: 36Issue: 1pp. 258-278See More RSNA Education Exhibits Big List of Malignant Small Round Cell Tumors: A Pictorial Exhibit on CTDigital Posters2018Stain Your Brain: Neuropathology of Pediatric Brain TumorsDigital Posters2018Li Fraumeni Syndrome: Genomics, Oncogenesis and Where to Look on Whole-Body Surveillance ImagingDigital Posters2019 RSNA Case Collection Ewing's sarcomaRSNA Case Collection2020Metastatic MedulloblastomaRSNA Case Collection2021Desmoplastic Small Round Cell Tumor RSNA Case Collection2021 Vol. 2, No. 5 Metrics Altmetric Score PDF download

Diffusion functional MRI reveals global brain network functional abnormalities driven by targeted local activity in a neuropsychiatric disease mouse model

Diffusion functional magnetic resonance imaging (DfMRI) has been proposed as an alternative functional imaging method to detect brain activity without confounding hemodynamic effects. Here, taking advantage of this DfMRI feature, we investigated abnormalities of dynamic brain function in a neuropsychiatric disease mouse model (glial glutamate transporter-knockdown mice with obsessive–compulsive disorder [OCD]-related behavior). Our DfMRI approaches consisted of three analyses: resting state brain activity, functional connectivity, and propagation of neural information. We detected hyperactivation and biased connectivity across the cortico-striatal-thalamic circuitry, which is consistent with known blood oxygen-level dependent (BOLD)-fMRI patterns in OCD patients. In addition, we performed ignition-driven mean integration (IDMI) analysis, which combined activity and connectivity analyses, to evaluate neural propagation initiated from brain activation. This analysis revealed an unbalanced distribution of neural propagation initiated from intrinsic local activation to the global network, while these were not detected by the conventional method with BOLD-fMRI. This abnormal function detected by DfMRI was associated with OCD-related behavior. Together, our comprehensive DfMRI approaches can successfully provide information on dynamic brain function in normal and diseased brains.

A method for high-content functional imaging of intracellular calcium responses in gelatin-immobilized non-adherent cells

Functional imaging of the intracellular calcium concentration [Ca2+]i using fluorescent indicators is a powerful and frequently applied method for assessing various biological questions in vitro, including ion channel function and intracellular signaling in homeostasis and disease. In functional [Ca2+]i imaging experiments, the fluorescence intensity of single cells is typically recorded during application of a chemical stimulus, i.e. by exchange of modified extracellular media, exposure to drugs and/or ligands. The concomitant mechanical perturbation caused by the perfusion of different solution during experimentation severely hinders calcium imaging in non-adherent cells, including peripheral immune cells, as cells in suspension are dislocated by turbulent flow during chemical stimulation. The quantitative analysis, involving time-courses of intracellular fluorescence signal changes, necessitates cells to remain at the same position throughout the experiment. To prevent dislocation of cells during solution exchange, and to enable imaging as well as analysis of Ca2+ responses in immune cells, a gelatin-based method for immobilization of non-adherent cells was developed. Gelatin has been a long-serving material for cell immobilization, e.g. in 3D bio-printing of cells and has thus, also been employed in the context of this study. To demonstrate the applicability of the established method for functional Ca2+ imaging in gelatin-immobilized suspension cells, a proof-of-concept study was conducted using human peripheral blood model cell lines (Jurkat/T-lymphocytes and THP-1/monocytes), Ca2+ indicators (Fluo-4 and Fura-2) and two different fluorescence microscopy rigs. The data presented that the established methodology is applicable for studying Ca2+ signaling by in vitro high-content functional imaging of [Ca2+]i in suspension cells, including but not restricted to human immune cells.

Association between end-induction response according to the revised International Neuroblastoma Response Criteria (INRC) and outcome in high-risk neuroblastoma patients.

The 1993 International Neuroblastoma Response Criteria (INRC) were revised in 2017 to include modern functional imaging studies and methods for quantifying disease in bone marrow. We hypothesized the 2017 INRC would enable more precise assessment of response to treatment and provide superior prognostic information compared with the 1993 criteria. High-risk (HR) neuroblastoma patients from two institutions in Chicago diagnosed between 2006 and 2016 were identified. Patients were assessed post induction chemotherapy via the 1993 and 2017 INRC and classified as responder(≥mixed response [MXR] or≥minor response [MR], respectively) or nonresponder(<MXR or<MR). Event-free survival (EFS) and overall survival (OS) for responders versus nonresponders were determined from end induction and stratified by Cox regression. Patients with progressive disease at end induction were eliminated from the EFS analyses but included in the OS analysis. The 1993 criteria classified 52 of the 60 HR patients as responders, whereas 54 responders were identified using the 2017 criteria (Spearman correlation r=0.82, P<0.001). No statistically significant difference in EFS was observed for responders versus nonresponders using either criteria (P=0.48 and P=0.08). However, superior OS was observed for responders (P=0.01) using either criteria. Both criteria were sensitive in identifying responders among those with good outcomes. The specificity to identify nonresponders among those with poor outcomes was poor. In HR neuroblastoma, end-induction response defined by the 1993 or 2017 INRC is associated with survival. Larger cohorts are needed to determine if the 2017 INRC provides more precise prognostication.

Portable Magnetometry for Detection of Biomagnetism in Ambient Environments

We present a method of optical magnetometry with parts-per-billion resolution that is able to detect biomagnetic signals generated from the human brain and heart in Earth's ambient environment. Our magnetically silent sensors measure the total magnetic field by detecting the free-precession frequency of highly spin-polarized alkali metal vapor. A first-order gradiometer is formed from two magnetometers that are separated by a 3 cm baseline. Our gradiometer operates from a laptop consuming 5 W over a USB port, enabled by state-of-the-art micro-fabricated alkali vapor cells, advanced thermal insulation, custom electronics, and laser packages within the sensor head. The gradiometer obtains a sensitivity of 16 fT/cm/Hz$^{1/2}$ outdoors, which we use to detect neuronal electrical currents and magnetic cardiography signals. Recording of neuronal magnetic fields is one of a few available methods for non-invasive functional brain imaging that usually requires extensive magnetic shielding and other infractructure. This work demonstrates the possibility of a dense array of portable biomagnetic sensors that are deployable in a variety of natural environments.

Chemogenetic silencing of neurons in the mouse anterior cingulate area modulates neuronal activity and functional connectivity

The anterior cingulate area (ACC) is an integral part of the prefrontal cortex in mice and supports cognitive functions, including attentional processes, motion planning and execution as well as remote memory, fear and pain. Previous anatomical and functional imaging studies demonstrated that the ACC is interconnected with numerous brain regions, such as motor and sensory cortices, amygdala and limbic areas, suggesting it serves as a hub in functional networks. However, the exact role of the ACC in regulating functional network activity and connectivity remains to be elucidated. Recently developed neuromodulatory techniques, such as Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) allow for precise control of neuronal activity. In this study, we used an inhibitory kappa-opioid receptor DREADD (KORD) to temporally inhibit neuronal firing in the right ACC of mice and assessed functional network activity and connectivity using non-invasive functional magnetic resonance imaging (MRI). We demonstrated that KORD-induced inhibition of the right ACC induced blood oxygenation-level dependent (BOLD) signal decreases and increases in connected brain regions of both hemispheres. More specifically, altered neuronal activity could be observed in functional brain networks including connections with sensory cortex, thalamus, basolateral amygdala and ventral pallidum, areas involved in attention processes, working memory, fear behavior and reward respectively. Furthermore, these modulations in neuronal activity were associated with decreased intra- and interhemispheric functional connectivity. Our results consolidate the hub role of the mouse ACC in functional networks and further demonstrate that the combination of the DREADD technology and non-invasive functional imaging methods is a valuable tool for unraveling mechanisms of network function and dysfunction by reversible inactivation of selected targets.

Tension headache. State of the problem, new aspects of etiopathogenesis, neuroimaging possibilities, non-drug treatment methods (review)

The prospects for the use of functional magnetic resonance imaging methods in the diagnosis of cognitive and neuropsychiatric disorders in patients with tension headaches are quite wide, as they allow a more detailed study of the pathogenesis of the above disorders. To date, the effectiveness of osteopathy in the treatment of patients with tension headaches has been shown. It remains an open question to develop a generally accepted method of diagnosis and treatment, including the use of complementary therapies, neuroimaging objectification and determination of the state of functional connections of the brain for more accurate diagnosis and prediction of treatment effectiveness. The present review summarizes the current ideas about the etiopathogenesis of tension headache (including the study of the functional connections of the brain) and available data on the clinical efficacy of osteopathic correction.

THU0306 ROLE OF 18-FDG PET/CT IN DIAGNOSIS AND FOLLOW UP OF LARGE VESSELS VASCULITIS

Background:18-FDG PET/CT is a functional imaging method which allows to identify inflammation of vessel walls. The use of PET in large vessels vasculitis(LVV) at disease onset and during follow up is still debate either to confirm clinical remission either to drive the therapy choice. American Society of Nuclear Cardiology (ASNC) recently advanced recommendations aimed to standardize the application of PET in LVV(1).Objectives:The aim of our study was to assess the clinical role of PET performed in patients affected by LVV at the diagnosis and during the follow up.Methods:We retrospectively evaluated PET/CT of 49 patients affected by clinically active LVV according to LVV visual grading (LVG, grading 0-3) and measured the standardized uptake value(SUV) of large vessels. 38 (77,6%) patients were affected by Giant Cells Arteritis and 11(22,4%) by Takayasu Arteritis. 32(65.3%) patients repeated the imaging after a mean follow-up of 11.5±5.4 months.All baseline (T0) and follow up (T1) clinical data of disease activity were collected. Patients were treated according to EULAR LVV management recommendations(2). T0 PET/CT study was performed in patients with a clinically active disease defined by suggestive symptoms/signs and/or high inflammatory markers. The mean disease duration before T1 PET/CT examination was 4 months. T0 PET was performed in 25/49 patients(52%) at the diagnosis of LVV, whereas in 24/49(48%) patients with already diagnosed but active LVV disease.Results:Baseline PET was positive in 21 patients(42.9%). According to ASNC recommendations, 19 patients (38.8%) presented a LVG=3, 2(4.0%) a LVG=2, 6(12.2%) LVG=1 and 22 (44.9%) LVG=0. Patients performing PET at disease onset(75%) had higher LVG score than patients performing PET during the disease course (25%),p=0,002. At T0, aortic, carotid, axillary and subclavian SUV did not correlate with inflammatory markers.Follow up PET/CT studies were performed in 32 patients, 13 (40.6%) with a clinically active disease despite therapy, while 19(59.4%) in clinical remission.Follow up PET was still positive in 8 patients (25%) with a LVG=3, 10 (31.2%) patients presented LVG=1 and 14 (43.8%) LVG=0. T1 PET/CT study showed a significant reduction of SUV values in descending aorta, left and right subclavian arteries, and left and right axillary arteries when compared with first PET/CT study. According to LVG, 12 patients with active PET/CT study at T0 (19 pts) presented a reduction of LVG from score 2 and 3 to grade 1 or 0 (64.2%) at second PET/CT study. Only 3 patients presented an increased LVG score at T1, while in the other 17 patients T1 PET confirmed the previous score. No significant difference was found between LVG scores according with clinical characteristics, but among 8 patients presenting an active T1 PET, 4(50%) were in clinical remission.Conclusion:The use of ASNC recommendations for FDG PET/CT in LVV enables to confirm a metabolically active disease in 40% of patients and in 75% of patients at disease onset, suggesting that post-posing the exam could lead to underrate the real extension of disease. Our data, even if limited, suggest that PET/CT could be crucial in management of patients in clinical remission, detecting patients with still metabolically active LVV. Further prospective studies are necessary to evaluate the role of PET/CT in driving therapeutic strategies.

Non-Invasive Functional Optical Brain Imaging Methods: A Review

Non-Invasive Functional Optical Brain Imaging Methods: A Review

Left Supraclavicular Lymph Node Metastasis from Ovarian Cancer Associated with Papillary Thyroid Microcarcinoma, a Confusing Pathology-Essential Role of Functional Imaging

The revolution of imaging in medicine leads to new standards of care, mostly in specialties like oncology, neurology, or endocrinology. We present a review of the literature and a case report of a 62-year-old patient initially treated for a benign gynecologic pathology and followed-up for 7 years clinically, with serologic and with multiple imaging techniques. There is an actual growing use of highly sensitive functional imaging methods, like fluoro-deoxy-glucose (F18-FDG) positron emission tomography/computed tomography (PET/CT) in the evaluation of oncologic pathologies, staging, follow-up, and therapy response monitoring. This is the first case report described in the literature presenting the association of thyroid papillary microcarcinoma (MPTC) and supraclavicular metastasis of ovarian cancer. The study aims to underline the necessity of a complex and careful evaluation of each oncologic patient, due to the unexpected clinical presentation and rare association of diseases, sometimes leading to confusing management.

Bionic Eye from the Point of View of Functional Magnetic Resonance and Electrophysiological Examination – Review

The aim of the study was to show not only a possible visual replacement in patients with loss of sight, but also to discuss its efficiency. The study is focused on the issue of transmission of electrical voltage changes in the visual pathway under physiological and pathological conditions. In particular, it points to the feedback autoregulatory damage, not only of the primarily altered cellular structures, but also of all other structures localised both horizontally and vertically. Based on the results of the functional magnetic resonance imaging and electrophysiological methods, it demonstrates the pathology of the entire visual pathway in three important eye diseases: pigmentary retinal dystrophy, age-related macular degeneration, and glaucoma. The study also provides an overview of possible systems used to replace loss of vision, ranging from epiretinal, subretinal, suprachoroidal implants to stimulation of the optic nerve, lateral geniculate nucleus and visual cortex. Regarding the pathophysiology of neurotransmission, it is assumed that recovery of sight using these systems is not possible.

A diagnostic strategy for Lewy body disease using DAT-SPECT, MIBG and Combined index.

The functional imaging methods widely used for the diagnosis of Lewy body disease (LBD) are 123I-N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl) nortropan (FP-CIT) with dopamine transporter single photon emission computed tomography (DAT-SPECT) and 123I-iodobenzylguanidine (MIBG) myocardial scintigraphy. The aim of this study was to determine whether DAT-SPECT or 123I-MIBG myocardial scintigraphy should be examined first and to evaluate whether the combined use of DAT-SPECT and MIBG myocardial scintigraphy is superior to using either modality alone for diagnosing suspected LBD. In this retrospective study, a total of 117 patients suspected of having LBD underwent DAT-SPECT imaging followed by MIBG myocardial scintigraphy. The delayed heart-to-mediastinum (H/M) ratio of MIBG scintigraphy, and the specific binding ratio (SBR) of DAT-SPECT imaging, and Combined index (defined as SBR mean×H/M in the delayed phase) were used as semi-quantitative measures. The diagnostic ability was evaluated using these indexes. The sensitivity, specificity, and accuracy of diagnosing Lewy body disease were 59.6%, 71.4%, and 67.5% by SBR mean of DAT-SPECT, 85.1%, 91.4%, and 88.9% by delayed H/M ratio of MIBG myocardial scintigraphy, 76.6%, 74.3%, and 75.2% by Combined index, respectively. In the diagnosis of LBD, DAT-SPECT, MIBG myocardial scintigraphy, and Combined index may be reliable indices. In particular, MIBG myocardial scintigraphy was the specific modality for LBD diagnosis. Understanding the effectiveness and limits of DAT-SPECT and MIBG myocardial scintigraphy and using both properly will lead to a more accurate diagnosis and better treatment.

MP50-08 DIFFUSION-WEIGHTED MRI AS AN IMAGING BIOMARKER OF THE FUHRMAN NUCLEAR GRADE OF CLEAR CELL RENAL CELL CARCINOMA

INTRODUCTION AND OBJECTIVE:Diffusion-weighted MRI (DWI) is a functional imaging method that visualizes the degree of water molecule diffusion within tissues. Its quantitative index, the apparent di...

Amygdala Functional Connectivity Features in Grief: A Pilot Longitudinal Study

ObjectiveAcute grief, in an important minority of older adults, can become protracted, intense, and debilitating, leading to the development of complicated grief (CG). However, the neurobiologic mechanisms underlying a maladaptive grief response after an attachment loss are unknown. The current study aimed to examine the amygdala brain network features that cross-sectionally explain the symptom variance and longitudinally relate to grief symptom trajectories after an attachment loss. MethodsBaseline amygdala functional connectivity (Fc) was assessed using a seed-based resting-state functional magnetic resonance imaging method in 35 adults who were within 1-year after death of a loved one and 21 healthy comparison (HC) participants. Magnetic resonance imaging scans were obtained at baseline, and clinical assessments, including the inventory of complicated grief (ICG) were completed at weeks 0, 8, 16, and 26 (endpoint). ResultsRelative to HC participants, grief participants showed increased amygdala Fc in the posterior default mode (bilateral medial temporal lobes and left precuneus) and thalamus. Amygdala Fc in the default mode and ventral affective regions positively correlated with ICG scores at baseline. Furthermore, increased baseline amygdala functional connections with the dorsal frontal executive control and salience network regions correlated with worsening ICG scores over time. These longitudinal findings persisted after controlling for covariates, including baseline depressive and anxiety symptoms. ConclusionThese results provide novel preliminary evidence suggesting amygdala-based brain network measures to cross-sectionally explain symptom variance and longitudinally correlate with grief symptom trajectories in grievers. Amygdala brain network function measures may have the potential to serve as biomarkers of CG.

Multiparametric Magnetic Resonance Imaging for the Diagnosis and Differential Diagnosis of Parotid Gland Tumors.

The majority of salivary gland tumors occur in the parotid glands. Characterization (ie, benign or malignant, and histological type), location (deep or superficial), and invasion into the neighboring tissues of parotid tumors determine preoperative treatment planning. MRI gives more information than other imaging methods about the internal structure, localization, and relationship with other tissues of parotid tumors. Functional MRI methods (diffusion-weighted imaging, dynamic contrast-enhanced MRI, perfusion-weighted MRI, MR spectroscopy, etc.) have been increasingly used recently to increase the power of radiologists to characterize the tumors. Although they increase the workload of radiologists, the combined use of functional MRI methods improves accuracy in the differentiation of the tumors. There are a wide range of studies in the literature dealing with the combined use of different functional imaging methods in combination with conventional sequences. The aim of the present review is to evaluate conventional and functional/advanced MR methods, as well as multiparametric MRI applications combining them in the diagnosis of parotid gland tumors. Evidence Level: 5 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2020;52:11-32.