Functional Imaging Modalities Research Articles

Metastatic Malignant Paraganglioma of Rare Sites Failed on Conventional Treatments Demonstrating Beneficial Response to 177Lu-DOTATATE PRRT

AbstractThe incidence of paraganglioma (PGL) is rising due to better imaging modalities employed for evaluating incidentaloma and surveillance of the asymptomatic carriers. Benign and malignant PGLs often cannot be reliably diagnosed on histology alone, and the documentation of metastases is important in the diagnosis of malignancy. Advancement in genomics has improved our understanding of PGL. 68Ga-DOTATATE positron emission tomography (PET)/computed tomography (CT) scan shows a significant superior detection rate compared with other conventional functional and anatomical imaging modalities, can detect rare sites of primary disease in PGL, and also aids in patient selection for peptide receptor radionuclide therapy (PRRT). PRRT is increasingly used in metastatic setting with good symptomatic and biochemical response and disease stabilization in metastatic PGL patients. We present a series of three patients with PGLs located in rare primary sites (sigmoid colon, urinary bladder, and carotid body space), which showed recurrence of disease on conventional treatments and developed metastatic disease in the lymph nodes, liver, skeleton, and lungs. PRRT with 177Lu-DOTATATE achieved symptom control, favorable biochemical and imaging responses, and increased progression-free and overall survival rate in the described patients.

Computed tomography perfusion as a predictor of gastric cancer grades

BackgroundGastric cancer stands as one of the most prevalent malignancies globally, conventional endoscopic specimens have been the primary means of diagnosing preoperative gastric histopathology, however, their limitations in capturing intra-tumor heterogeneity compromise their efficacy in evaluating angiogenesis. Perfusion Computed Tomography (P-CT) emerges as a pivotal functional imaging modality, facilitating objective assessment of tissue perfusion, serving as a marker of angiogenesis. So, our research objective was to evaluate the efficacy of CT perfusion imaging in the prediction of histological grades of gastric tumors using quantitative perfusion parameters such as permeability surface (PS), blood flow (BF), mean transient time (MTT), and blood volume (BV), in addition to the qualitative scoring system then comparing the findings with the histopathological results.ResultsPS and BF were statistically significant predictors of the grade of differentiation, their odds ratio (OR) was (1.05, 95% CI 1.02–1.09, for each of them) (P = 0.004, P = 0.009, respectively). MTT also emerged as a significant predictor of the grade of differentiation with an OR of 0.76 (95% CI 0.57–0.93, P = 0.025). Using multivariate logistic regression model, PS was the most potent individual P-CT predictor of differentiation of the grade and the diagnosis of poorly differentiated tumors at ≥ 39 mL/100 g/min cut off point, followed by BF at ≥ 82.2 mL/100 g/min, and MTT at < 8.4 s. Regarding the qualitative scoring system P-CT, poorly differentiated tumors generally received higher scores of PS (P < 0.001), BF (P < 0.001), and BV (P = 0.017), than well and moderately differentiated tumors, however, MTT showed that poorly differentiated tumors were more frequently scored as low compared to well and moderately differentiated tumors (P < 0.001).ConclusionsP-CT is an innovative, non-invasive biomarker for predicting gastric cancer grade by quantitative and qualitative assessment by P-CT parameters (PS, BF and MTT) with particular role of PS as the strongest individual P-CT predictor of differentiation grade followed by BF and MTT at specific cut off points.

Diffuse correlation tomography: a technique to characterize tissue blood flow abnormalities in benign and malignant breast lesions

Accurate assessment and quantification of neoangiogenesis associated with breast cancer could be potentially used to improve the sensitivity and specificity of non-invasive diagnosis, as well as predict outcomes and monitor treatment effects. In this study, we adapted an emerging technology, namely diffuse correlation tomography (DCT), to image microvascular blood flow in breast tissues and evaluate the potential for discriminating between benign and malignant lesions. A custom-made DCT system was designed for breast blood flow imaging, with both the source-detector array and reconstruction algorithm optimized to ensure precise imaging of breast blood flow. The global features and local features of three-dimensional blood flow images were extracted from the relative blood flow index (rBFI), which was obtained from most of the breasts targeted to the lesion. A total of 37 women with 19 benign and 18 malignant lesions were included in the study. Significant differences between malignant and benign groups were found in 12 image features. Moreover, when selecting the lesion mean relative blood flow index (MrBFI) as a single indicator, the malignant and benign tumors were discriminated with an accuracy of 89.2%. The blood flow features were found to successfully identify malignant and benign tumors, suggesting that DCT, as an alternate functional imaging modality, has the potential to be translated into clinical practice for diagnosis and assessment of breast cancers. There is potential to reduce the need for biopsy of benign lesions by improving the specificity of diagnostic imaging, as well as monitoring response to breast cancer treatment.

Biology-guided radiotherapy in metastatic prostate cancer: time to push the envelope?

The therapeutic landscape of metastatic prostate cancer has undergone a profound revolution in recent years. In addition to the introduction of novel molecules in the clinics, the field has witnessed a tremendous development of functional imaging modalities adding new biological insights which can ultimately inform tailored treatment strategies, including local therapies. The evolution and rise of Stereotactic Body Radiotherapy (SBRT) have been particularly notable in patients with oligometastatic disease, where it has been demonstrated to be a safe and effective treatment strategy yielding favorable results in terms of disease control and improved oncological outcomes. The possibility of debulking all sites of disease, matched with the ambition of potentially extending this treatment paradigm to polymetastatic patients in the not-too-distant future, makes Biology-guided Radiotherapy (BgRT) an attractive paradigm which can be used in conjunction with systemic therapy in the management of patients with metastatic prostate cancer.

Photoacoustic Quantification of Tissue Oxygenation Using Conditional Invertible Neural Networks.

Intelligent systems in interventional healthcare depend on the reliable perception of the environment. In this context, photoacoustic tomography (PAT) has emerged as a non-invasive, functional imaging modality with great clinical potential. Current research focuses on converting the high-dimensional, not human-interpretable spectral data into the underlying functional information, specifically the blood oxygenation. One of the largely unexplored issues stalling clinical advances is the fact that the quantification problem is ambiguous, i.e. that radically different tissue parameter configurations could lead to almost identical photoacoustic spectra. In the present work, we tackle this problem with conditional Invertible Neural Networks (cINNs). Going beyond traditional point estimates, our network is used to compute an approximation of the conditional posterior density of tissue parameters given the photoacoustic spectrum. To this end, an automatic mode detection algorithm extracts the plausible solution from the sample-based posterior. According to a comprehensive validation study based on both synthetic and real images, our approach is well-suited for exploring ambiguity in quantitative PAT.

Regulating posttraumatic stress disorder symptoms with neurofeedback: Regaining control of the mind

Neurofeedback is emerging as a psychophysiological treatment where self-regulation is achieved through online feed-back of neural states. Novel personalized medicine approaches are particularly important for the treatment of posttrau-matic stress disorder (PTSD), as symptom presentation of the disorder, as well as responses to treatment, are highly het-erogeneous. Learning to achieve control of specific neural substrates through neurofeedback has been shown to display therapeutic evidence in patients with a wide variety of psychiatric disorders, including PTSD. This article outlines the neural mechanisms underlying neurofeedback and examines converging evidence for the efficacy of neurofeedback as an adjunctive treatment for PTSD via both electroencephalography (EEG) and real-time functional magnetic resonance imaging (fMRI) modalities. Further, implications for the treatment of PTSD via neurofeedback in the military mem-ber and Veteran population is examined.

Improving source estimation of retinotopic MEG responses by combining data from multiple subjects

Abstract Magnetoencephalography (MEG) is a functional brain imaging modality, which measures the weak magnetic field arising from neuronal activity. The source amplitudes and locations are estimated from the sensor data by solving an ill-posed inverse problem. Commonly used solutions for these problems operate on data from individual subjects. Combining the measurements of multiple subjects has been suggested to increase the spatial resolution of MEG by leveraging the intersubject differences for increased information. In this article, we compare 3 multisubject analysis methods on a retinotopic mapping dataset recorded from 20 subjects. The compared methods are eLORETA with source-space averaging, minimum Wasserstein estimates (MWE), and MWE with source-space averaging. The results were quantified by the geodesic distances between early (60–100 ms) MEG peak activations and fMRI-based retinotopic target points in the primary visual cortex (V1). By increasing the subject count from 1 to 10, the median distances decreased by 6.6–9.4 mm (33–46%) compared with the single-subject median distances of around 20 mm. The observed peak activation locations with multisubject analysis also comply better with the established retinotopic maps of the primary visual cortex. Our results suggest that higher spatial accuracy can be achieved by pooling data from multiple subjects. The strength of MWE lies in individualized and sparse source estimates, but in our data, averaging eLORETA estimates across individuals in source space outperformed MWE in spatial accuracy.

Functional near-infrared spectroscopy and language development: An integrative review.

Functional near-infrared spectroscopy (fNIRS) stands poised to revolutionize our understanding of auditory detection, speech perception, and language development in infants. In this study, we conducted a meticulous integrative review across Medline, Scopus, and LILACS databases, targeting investigations utilizing fNIRS to explore language-related features and cortical activation during auditory stimuli in typical infants. We included studies that used the NIRS technique to study language and cortical activation in response to auditory stimuli in typical infants between 0 and 3years old. We used the ROBINS-I tool to assess the quality and the risk of bias in the studies. Our analysis, encompassing 66 manuscripts, is presented in standardized tables for streamlined data extraction. We meticulously correlated findings with children's developmental stages, delineating crucial insights into brain development and its intricate interplay with language outcomes. Although most studies have a high risk for overall bias, especially due to the high loss of data in NIRS studies, the low risk in the other domains is predominant and homogeneous among the studies. Highlighted are the unique advantages of fNIRS for pediatric studies, underscored by its innate suitability for use in children. This review accentuates fNIRS' capacity to elucidate the neural correlates of language processing and the sequential steps of language acquisition. From birth, infants exhibit abilities that lay the foundation for language development. The progression from diffuse to specific neural activation patterns is extremely influenced by exposure to languages, social interaction, and prosodic features and, reflects the maturation of brain networks involved in language processing. In conclusion, fNIRS emerges as an indispensable functional imaging modality, providing insights into the temporal dynamics of language acquisition and associated developmental milestones. This synthesis presents the pivotal role of fNIRS in advancing our comprehension of early language development and paves the way for future research endeavors in this domain.

Role of [18F]FDG-PET/CT in Evaluation of Tumor Response to Chemoradiation Therapy for Advanced Colorectal Cancer

Objectives: The objective is to evaluate the efficacy of 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) computed tomography (CT) in the evaluation of tumor response to preoperative/palliative chemoradiotherapy (CRT) for advanced colorectal cancer; including metastatic cancer at primary presentation and recurrent cancers with local and/or distant metastasis. Materials and Methods: Fifty patients with advanced rectal cancer underwent two point imaging with 18 FDG PET-CT before and after 3 weeks of completion of preoperative/palliative CRT in between 2016 and 2022. Patients with locally recurrent cancer also underwent radical surgery. The assessment consisted of the evaluation of the following metabolic PET parameters: Maximum standardized uptake value (SUVmax), SUVratio, metabolic tumor volume (MTV), and total lesion glycolysis (TLG). Response was assessed among the followed patients using RECIST 1.1 criteria. Observations and Results: There was a significant decline in the mean post therapy SUVmax and SUVratio as compared to baseline (P = 0.0001). Twenty-six out of 50 (52%) patients were classified as responders. A significant decrease in all parameters (SUVmax, SUVratio, TLG, and MTV) from baseline was observed in responders of the study when comparing with nonresponders (P &lt; 0.05). Besides SUVmax and SUVratio, the mean posttherapy TLG was significantly reduced in responders than nonresponders (P = 0.0065). Conclusion: PET-CT is a useful combined anatomic and functional imaging modality in monitoring tumor response to preoperative/palliative CRT in advanced rectal cancer, whether primary or recurrent, including metastatic cancers at presentation. Posttherapy SUV and TLG in particular are significantly associated with treatment response.

Emerging Novel Functional Imaging and Immunotherapy in Renal Cell Carcinoma and Current Treatment Sequencing Strategies After Immunotherapy.

The management of renal cell carcinoma (RCC) has advanced significantly in the past two decades. Many promising functional imaging modalities such as radiolabeled tracer targeting carbonic anhydrase IX and prostate-specific membrane antigen are under development to detect primary kidney tumors, stage systemic disease, and assess treatment response in RCC. Immune checkpoint inhibitors targeting PD-1 and cytotoxic T-cell lymphocyte-4 have changed the treatment paradigm in advanced RCC. Trials investigating novel mechanisms such as LAG-3 immune checkpoint inhibition, chimeric antigen receptor T-cell therapies, and T-cell engagers targeting RCC-associated antigens are currently ongoing. With the rapidly changing treatment landscape of RCC, the treatment sequence strategies will continue to evolve. Familiarity with the toxicities associated with the therapeutic agents and how to manage them are essential to achieve optimal patient outcomes. This review summarizes the recent developments of functional imaging and immunotherapy strategies in RCC, and the evidence supports treatment sequencing.

Functional ultrasound imaging of human brain activity through an acoustically transparent cranial window.

Visualization of human brain activity is crucial for understanding normal and aberrant brain function. Currently available neural activity recording methods are highly invasive, have low sensitivity, and cannot be conducted outside of an operating room. Functional ultrasound imaging (fUSI) is an emerging technique that offers sensitive, large-scale, high-resolution neural imaging; however, fUSI cannot be performed through the adult human skull. Here, we used a polymeric skull replacement material to create an acoustic window compatible with fUSI to monitor adult human brain activity in a single individual. Using an in vitro cerebrovascular phantom to mimic brain vasculature and an in vivo rodent cranial defect model, first, we evaluated the fUSI signal intensity and signal-to-noise ratio through polymethyl methacrylate (PMMA) cranial implants of different thicknesses or a titanium mesh implant. We found that rat brain neural activity could be recorded with high sensitivity through a PMMA implant using a dedicated fUSI pulse sequence. We then designed a custom ultrasound-transparent cranial window implant for an adult patient undergoing reconstructive skull surgery after traumatic brain injury. We showed that fUSI could record brain activity in an awake human outside of the operating room. In a video game "connect the dots" task, we demonstrated mapping and decoding of task-modulated cortical activity in this individual. In a guitar-strumming task, we mapped additional task-specific cortical responses. Our proof-of-principle study shows that fUSI can be used as a high-resolution (200 μm) functional imaging modality for measuring adult human brain activity through an acoustically transparent cranial window.

Speckle-enabled in vivo demixing of neural activity in the mouse brain.

Functional imaging of neuronal activity in awake animals, using a combination of fluorescent reporters of neuronal activity and various types of microscopy modalities, has become an indispensable tool in neuroscience. While various imaging modalities based on one-photon (1P) excitation and parallel (camera-based) acquisition have been successfully used for imaging more transparent samples, when imaging mammalian brain tissue, due to their scattering properties, two-photon (2P) microscopy systems are necessary. In 2P microscopy, the longer excitation wavelengths reduce the amount of scattering while the diffraction-limited 3D localization of excitation largely eliminates out-of-focus fluorescence. However, this comes at the cost of time-consuming serial scanning of the excitation spot and more complex and expensive instrumentation. Thus, functional 1P imaging modalities that can be used beyond the most transparent specimen are highly desirable. Here, we transform light scattering from an obstacle into a tool. We use speckles with their unique patterns and contrast, formed when fluorescence from individual neurons propagates through rodent cortical tissue, to encode neuronal activity. Spatiotemporal demixing of these patterns then enables functional recording of neuronal activity from a group of discriminable sources. For the first time, we provide an experimental, in vivo characterization of speckle generation, speckle imaging and speckle-assisted demixing of neuronal activity signals in the scattering mammalian brain tissue. We found that despite an initial fast speckle decorrelation, substantial correlation was maintained over minute-long timescales that contributed to our ability to demix temporal activity traces in the mouse brain in vivo. Informed by in vivo quantifications of speckle patterns from single and multiple neurons excited using 2P scanning excitation, we recorded and demixed activity from several sources excited using 1P oblique illumination. In our proof-of-principle experiments, we demonstrate in vivo speckle-assisted demixing of functional signals from groups of sources in a depth range of 220-320 µm in mouse cortex, limited by available speckle contrast. Our results serve as a basis for designing an in vivo functional speckle imaging modality and for maximizing the key resource in any such modality, the speckle contrast. We anticipate that our results will provide critical quantitative guidance to the community for designing techniques that overcome light scattering as a fundamental limitation in bioimaging.

PRESERVING HUMAN LARGE-SCALE BRAIN CONNECTIVITY FINGERPRINT IDENTIFIABILITY WITH RANDOM PROJECTIONS.

The complex etiology of various neurodegenerative diseases and psychiatric disorders, especially at the individual level, has posed unmatched challenges to the advancement of personalized medicine. Recent technical advancements in functional magnetic resonance imaging has enabled researchers to map brain large-scale connectivity at an unprecedented level of subject precision. Nonetheless, along with the early dawn of promises in personalized medicine using various neuroimaging modalities rose the challenge of clinical utility of brain connectomics (e.g., functional connectomes). Besides many established challenges of functional connectome utility such as edge reliability, there exists an easily overlooked challenge that does not get the same level of attention: computationality of functional connectome. To improve clinical utility of functional connectomics, we propose a random projection method that would preserve a practically similar level of subject identifiability while sampling and retaining only a proportion of functional edges in subjects' functional connectome. Our work pave a way towards computational improvements, hence clinical utility, of functional connectomes while not compromising the integrity of biomarkers learnt from whole-brain large-scale functional connectivity imaging modality.

Diagnostic performance of [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the spine, and whole-body diagnostic CT and MRI in the detection of spinal bone metastases associated with pheochromocytoma and paraganglioma

ObjectiveTo compare the diagnostic performance of [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the spine, and whole-body CT and MRI for the detection of pheochromocytoma/paraganglioma (PPGL)–related spinal bone metastases.Materials and methodsBetween 2014 and 2020, PPGL participants with spinal bone metastases prospectively underwent [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the cervical-thoracolumbar spine (MRIspine), contrast-enhanced MRI of the neck and thoraco-abdominopelvic regions (MRIWB), and contrast-enhanced CT of the neck and thoraco-abdominopelvic regions (CTWB). Per-patient and per-lesion detection rates were calculated. Counting of spinal bone metastases was limited to a maximum of one lesion per vertebrae. A composite of all functional and anatomic imaging served as an imaging comparator. The McNemar test compared detection rates between the scans. Two-sided p values were reported.ResultsForty-three consecutive participants (mean age, 41.7 ± 15.7 years; females, 22) with MRIspine were included who also underwent [68Ga]DOTATATE PET/CT (n = 43), [18F]FDG PET/CT (n = 43), MRIWB (n = 24), and CTWB (n = 33). Forty-one of 43 participants were positive for spinal bone metastases, with 382 lesions on the imaging comparator. [68Ga]DOTATATE PET/CT demonstrated a per-lesion detection rate of 377/382 (98.7%) which was superior compared to [18F]FDG (72.0%, 275/382, p < 0.001), MRIspine (80.6%, 308/382, p < 0.001), MRIWB (55.3%, 136/246, p < 0.001), and CTWB (44.8%, 132/295, p < 0.001). The per-patient detection rate of [68Ga]DOTATATE PET/CT was 41/41 (100%) which was higher compared to [18F]FDG PET/CT (90.2%, 37/41, p = 0.13), MRIspine (97.6%, 40/41, p = 1.00), MRIWB (95.7%, 22/23, p = 1.00), and CTWB (81.8%, 27/33, p = 0.03).Conclusions[68Ga]DOTATATE PET/CT should be the modality of choice in PPGL-related spinal bone metastases due to its superior detection rate.Clinical relevance statementIn a prospective study of 43 pheochromocytoma/paraganglioma participants with spinal bone metastases, [68Ga]DOTATATE PET/CT had a superior per-lesion detection rate of 98.7% (377/382), compared to [18F]FDG PET/CT (p < 0.001), MRI of the spine (p < 0.001), whole-body CT (p < 0.001), and whole-body MRI (p < 0.001).Graphical abstractKey Points• Data regarding head-to-head comparison between functional and anatomic imaging modalities to detect spinal bone metastases in pheochromocytoma/paraganglioma are limited.• [68Ga]DOTATATE PET/CT had a superior per-lesion detection rate of 98.7% in the detection of spinal bone metastases associated with pheochromocytoma/paraganglioma compared to other imaging modalities: [18]F-FDG PET/CT, MRI of the spine, whole-body CT, and whole-body MRI.• [68Ga]DOTATATE PET/CT should be the modality of choice in the evaluation of spinal bone metastases associated with pheochromocytoma/paraganglioma.

3-[18F]Fluoro-para-hydroxyphenethylguanidine (3-[18F]pHPG) PET-A Novel Imaging Modality for Paraganglioma.

Functional positron emission tomography (PET) imaging for the characterization of pheochromocytoma and paraganglioma (PCC/PGL) and for detection of metastases in malignant disease, offers valuable clinical insights that can significantly guide patient treatment. This work aimed to evaluate a novel PET radiotracer, 3-[18F]fluoro-para-hydroxyphenethylguanidine (3-[18F]pHPG), a norepinephrine analogue, for its ability to localize PCC/PGL. 3-[18F]pHPG PET/CT whole-body scans were performed on 16 patients (8 male:8 female; mean age 47.6 ± 17.6 years; range, 19-74 years) with pathologically confirmed or clinically diagnosed PCC/PGL. After intravenous administration of 304 to 475 MBq (8.2-12.8 mCi) of 3-[18F]pHPG, whole-body PET scans were performed at 90 minutes in all patients. 3-[18F]pHPG PET was interpreted for abnormal findings consistent with primary tumor or metastasis, and biodistribution in normal organs recorded. Standardized uptake value (SUV) measurements were obtained for target lesions and physiological organ distributions. 3-[18F]pHPG PET showed high radiotracer uptake and trapping in primary tumors, and metastatic tumor lesions that included bone, lymph nodes, and other solid organ sites. Physiological biodistribution was universally present in salivary glands (parotid, submandibular, sublingual), thyroid, heart, liver, adrenals, kidneys, and bladder. Comparison [68Ga]DOTATATE PET/CT was available in 10 patients and in all cases showed concordant distribution. Comparison [123I]meta-iodobenzylguanidine [123I]mIBG planar scintigraphy and SPECT/CT scans were available for 4 patients, with 3-[18F]pHPG showing a greater number of metastatic lesions. We found the kinetic profile of 3-[18F]pHPG PET affords high activity retention within benign and metastatic PCC/PGL. Therefore, 3-[18F]pHPG PET imaging provides a novel modality for functional imaging and staging of malignant paraganglioma with advantages of high lesion affinity, whole-body coregistered computed tomography, and rapid same-day imaging.

Improving photoacoustic imaging through the skull using deep learning: a numerical study

Photoacoustic computed tomography (PACT) has recently emerged as an attractive imaging modality for functional brain imaging due to its rich optical absorption contrast, high spatial and temporal resolutions, and relatively deep penetration. However, a major hurdle in using PACT for the human brain is distortion of the signal due to the skull, which negatively affects the quality of the images. In this project, we aimed to improve transcranial PACT using a U-Net architecture that can minimize distortion from the skull. This numerical study utilized a large collection of blood vessel images obtained from an online database and a computed tomography (CT) scan of an ex vivo human skull. The synthetic photoacoustic radiofrequency data were generated using the open-source wave solver k-Wave. Comparing the images generated by deep learning with the ground truth images, we achieved an average structural similarity index of 0.874 and an average peak signal-to-noise ratio of 17.92 dB.

Brown adipose tissue – magnetic resonance imaging (MRI) appearance of these physiological fat deposits in a newborn

Brown adipose tissue (BAT) is responsible for thermogenesis in neonates and infants in response to cold environment. 18F-fluorodeoxyglucose positron emission tomography is the reference for imaging of BAT, but it is a functional imaging modality and hence lacks sensitivity due to varying patient and environmental factors. Magnetic resonance imaging (MRI) lacks the use of radioactivity and ionizing radiation and can prove to be an excellent imaging modality to study the distribution of BAT. We report a neonate with sepsis whose MRI study of the neck and upper chest done to look for infective focus revealed classical distribution and signal intensity of BAT.

Role of epicardial adipose tissue in diabetic cardiomyopathy through the lens of cardiovascular magnetic resonance imaging - a narrative review.

Accumulating evidence suggests that ectopic/visceral adiposity may play a key role in the pathogenesis of nonischaemic cardiovascular diseases associated with type 2 diabetes. Epicardial adipose tissue (EAT) is a complex visceral fat depot, covering 80% of the cardiac surface with anatomical and functional contiguity to the myocardium and coronary arteries. EAT interacts with the biology of the underlying myocardium by secreting a wide range of adipokines. Magnetic resonance imaging (MRI) is the reference modality for structural and functional imaging of the heart. The technique is now also emerging as the reference imaging modality for EAT quantification. With this narrative review, we (a) surveyed contemporary clinical studies that utilized cardiovascular MRI to characterize EAT (studies published 2010-2023); (b) listed the clinical trials monitoring the response to treatment in EAT size as well as myocardial functional and structural parameters and (c) discussed the potential pathophysiological role of EAT in the development of diabetic cardiomyopathy. We concluded that increased EAT quantity and its inflammatory phenotype correlate with early signs of left ventricle dysfunction and may have a role in the pathogenesis of cardiac disease in diabetes with and without coronary artery disease.

The Evaluation of Primary Brain Tumors: The Role of CT and MRI

Primary brain tumors are a serious problem for neurology and oncology. Imaging serves as an indispensable cornerstone in the management of patients grappling with brain tumors. Primary brain tumors impose a substantial burden on individuals' lives and on public healthcare systems.]This literature review delves into the essential roles of MRI and CT in diagnosing and evaluating primary brain cancers. It discusses emerging imaging techniques, contrast agents, and functional imaging modalities that further enhance the accuracy of brain tumor assessment By summarizing the latest research, the review underscores how the synergy between MRI and CT contributes to more precise diagnosis, treatment planning, and post-treatment monitoring of individuals with brain tumors. Imaging techniques, notably computed tomography (CT) and magnetic resonance imaging (MRI), have evolved significantly in their ability to detect and characterize brain tumors. Computed tomography is non- invasive and provides three-dimensional cross-sectional anatomy of the brain, which can be reformatted in multiple planes. Computed tomography provides more detail about the nature of calcification and can characterize soft tissue abnormalities with high contrast and good spatial resolution. Magnetic resonance imaging is noninvasive and provides three-dimensional cross-sectional anatomy of the brain, which can be acquired in multiple planes. The dominant modality used is MRI because of its superior image resolution, speed of acquisition, and high safety profile for patients.

Focal Congenital Hyperinsulinism (CHI) Due To Paternally Inherited Variant in ABCC8 Gene: Importance of Genetic Testing &amp; PET Imaging in Stratification &amp; Management of Diazoxide Unresponsive CHI

Congenital Hyperinsulinism (CHI) may be transient or permanent and inherited either in autosomal recessive or dominant forms. Variants in ABCC8 and KCNJ11 genes coding for Sulphonyl Urea Receptor (SUR1) and potassium channel subunit (Kir6.2) respectively, account for 82% cases of diazoxide-unresponsive patients and 45% of all cases of CHI. The histology of CHI is classified into focal and diffuse. Approximately half of all cases can be classified as diffuse, 40 % as focal, and 10% of cases are considered atypical. We report a 1 month old male with recurrent hypoglycemia detected with focal congenital hyperinsulinism secondary to a paternally inherited heterozygous ABCC8 gene mutation. Focal disease results due to inheritance of a monoallelic recessive paternal ABCC8 or KCNJ11 variant together with somatic Loss of Heterozygosity (LOH) of the maternal allele at 11p15 within a pancreatic progenitor cell. Infants &amp; children with focal disease may be cured by resection of their hyperplastic lesion and the risk for postoperative diabetes is significantly lower as compared to that following pancreatectomy for diffuse CHI. The report describes molecular mechanisms underlying CHI &amp; emphasises the need of genetic testing and diagnostic functional imaging modalities in diazoxide unresponsive CHI to guide management and improve clinical outcomes.