3.0 T diffusion tensor imaging and fiber tractography of the testes in nonobstructive azoospermia.

PURPOSE: To assess the role of 3.0 T Diffusion Tensor Imaging (DTI) and Fiber Tractography (FT) of the testes in the work-up of nonobstructive azoospermia (NOA). METHODS: This prospective study included consecutive NOA men and controls. A 3.0 T scrotal MRI was performed, including DTI. The testicular apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were calculated. FT reconstructions were created. The Kruskal-Wallis test, followed by pairwise comparisons, assessed differences in testicular ADC and FA between NOA histologic phenotypes (group 1: hypospermatogenesis; group 2: maturation arrest; and group 3: Sertoli cell-only syndrome) and normal testes. The Mann-Whitney-U test compared ADC and FA between NOA testes with positive and negative sperm retrieval. Visual assessment of the testicular fiber tracts was performed. Fiber tracts fewer in number, of reduced thickness, disrupted and/or disorganized were considered "abnormal". Chi-square tests and binary logistic regression analysis assessed variations in testicular fiber tracts morphology. RESULTS: Twenty-nine NOA men (mean age: 39 ± 5.93 years) and 20 controls (mean age: 26 ± 5.83 years) were included for analysis. Higher ADC (p < 0.001) and FA (p < 0.001) was observed in NOA testes compared to controls. Differences in FA were found between groups 1 and 3 (0.07 vs 0.10, p = 0.26) and groups 2 and 3 (0.07 vs 0.10, p = 0.03), but not between groups 1 and 2 (p = 0.66). An increase in FA was observed in NOA testes with Sertoli cell-only syndrome compared to hypospermatogenesis and maturation arrest. FA was higher in NOA testes with negative results for the presence of sperm compared to those with positive results (0.09 vs 0.07, p = 0.006). FT showed "abnormal" fiber tracts in NOA testes (p < 0.001). CONCLUSION: 3.0 T DTI and FT provide an insight into deranged spermatogenesis in NOA testes.

Diffusion tensor imaging and fiber tractography of the normal epididymis.

PURPOSE: To evaluate the feasibility of diffusion tensor imaging (DTI) and fiber tractography (FT) of the normal epididymis and to determine normative apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values. METHODS: Twenty-eight healthy volunteers underwent MRI of the scrotum, including DTI on a 3.0 T system. For each anatomic part of the epididymis (head, body and tail) free-hand regions of interest were drawn and the mean ADC and FA were measured by two radiologists in consensus. Parametric statistical tests were used to determine intersubject differences in ADC and FA between the anatomic parts of each normal epididymis and between bilateral epididymides. Fiber tracts of the epididymis were reconstructed using the MR Diffusion tool. RESULTS: The mean ADC and FA of the normal epididymis was 1.31 × 10-3 mm2/s and 0.20, respectively. No differences in ADC (p = 0.736) and FA (p = 0.628) between the anatomic parts of each normal epididymis were found. Differences (p = 0.020) were observed in FA of the body between the right and the left epididymis. FT showed the fiber tracts of the normal epididymis. Main study's limitations include the following: small number of participants with narrow age range, absence of histologic confirmation and lack of quantitative assessment of the FT reconstructions. CONCLUSION: DTI and FT of the normal epididymis is feasible and allow the noninvasive assessment of the structural and geometric organization of the organ.

Survival Outcome Prediction in Glioblastoma: Insights from MRI Radiomics.

Background: Extracting multiregional radiomic features from multiparametric MRI for predicting pretreatment survival in isocitrate dehydrogenase (IDH) wild-type glioblastoma (GBM) patients is a promising approach. Methods: MRI data from 49 IDH wild-type glioblastoma patients pre-treatment were utilized. Diffusion and perfusion maps were generated, and tumor subregions segmented. Radiomic features were extracted for each tissue type and map. Feature selection on 1862 radiomic features identified 25 significant features. The Cox proportional-hazards model with LASSO regularization was used to perform survival analysis. Internal and external validation used a 38-patient training cohort and an 11-patient validation cohort. Statistical significance was set at p < 0.05. Results: Age and six radiomic features (shape and first and second order) from T1W, diffusion, and perfusion maps contributed to the final model. Findings suggest that a small necrotic subregion, inhomogeneous vascularization in the solid non-enhancing subregion, and edema-related tissue damage in the enhancing and edema subregions are linked to poor survival. The model's C-Index was 0.66 (95% C.I. 0.54-0.80). External validation demonstrated good accuracy (AUC > 0.65) at all time points. Conclusions: Radiomics analysis, utilizing segmented perfusion and diffusion maps, provide predictive indicators of survival in IDH wild-type glioblastoma patients, revealing associations with microstructural and vascular heterogeneity in the tumor.

Pituitary gland height evaluated with magnetic resonance imaging in premature twins: the impact of growth and sex.

BACKGROUND: Pituitary gland height reflects secretory activity of the hypothalamo-pituitary axis. OBJECTIVE: To assess the cumulative impact of fetal growth and sex on pituitary gland height in premature twins, dissociated from prematurity. MATERIALS AND METHODS: A retrospective study was conducted, assessing the pituitary gland height in 63 pairs of preterm twins, measured from T1-weighted magnetic resonance imaging (MRI). Auxological parameters, including body weight, body length, and head circumference, at birth and at the time of MRI, were used as proxies for fetal and postnatal growth, respectively. The study population was divided into two groups, using corrected age at around term equivalent as the cutoff point. Statistical analysis was performed using mixed-effects linear regression models. RESULTS: When pituitary gland height was evaluated at around term equivalent, a greater pituitary gland height, suggesting a more immature hypothamo-pituitary axis, was associated with the twin exhibiting lower auxological data at birth. The same association was observed when body weight and length at MRI were used as covariants. In the group evaluated after term equivalent, a smaller pituitary gland height, suggesting a more mature hypothamo-pituitary axis, was associated with male sex. This difference was observed in twin pairs with higher average body weight at birth, and in babies exhibiting higher auxological data at MRI. CONCLUSION: After isolating the effect of prematurity, at around term equivalent, pituitary gland height reflects the cumulative impact of fetal growth on the hypothalamo-pituitary axis. Subsequently, pituitary gland height shows effects of sex and of fetal and postnatal growth.

"Long-term MRI findings in Ankylosing spondylitis patients treated with TNF inhibitors for a decade".

OBJECTIVE: This study aims to evaluate the active and chronic lesions in sacroiliac joints and lumbar spine over a decade of TNFi therapy in patients with AS. METHODS: The study enrolled patients with AS under treatment with a TNFi for over a decade. The patients underwent a new MRI scan of their lumbar spine and sacroiliac joint (SIJ). Two readers evaluated all images. Inflammation of SIJ (SIS), SIJ structural damage (SSS) including Fat Metaplasia, Erosions, Backfill and Ankylosis, and Spondyloarthritis Research Consortium of Canada Bone marrow edema (SPARCC) spine score were recorded. RESULTS: In the study, 15 patients were included, with 80% being male. The mean age during their first MRI was 38.1 (± 11.9) years old, and the majority (86.7%) tested positive for HLA-B27. While TNFi improved both BASDAI and BASFI scores, there was a noticeable increase in MRI acute lesions in the SIJ over time, where the median score increased from 0 (0-4) to 3 (0-10) after ten years (p = 0.028). After a decade of treatment, the median SPARCC spine score also increased from 0 (0-9) to 5 (0-16), p = 0.093. Finally, it was observed that there was a significant positive correlation between ESR and SIS erosions in cases of chronic lesions (r = 0.819, p < 0.001). CONCLUSIONS: While TNFi have significantly improved the treatment of AS, this study shows that acute lesions can still develop despite treatment. A personalized approach that adapts MRI assessment to each patient's specific requirements may help detect changes early and enable doctors to intervene promptly to prevent further damage.

The role of ventral tegmental area in chronic stroke rehabilitation: an exploratory study.

Introduction: The acknowledged role of external rewards in chronic stroke rehabilitation, offering positive reinforcement and motivation, has significantly contributed to patient engagement and perseverance. However, the exploration of self-reward's importance in this context remains limited. This study aims to investigate the functional connectivity of the ventral tegmental area (VTA), a key node in the brain's reward circuitry, during motor task-based rehabilitation and its correlation with the recovery process. Methods: Twelve right-handed healthy volunteers (4 men, 8 women, aged 57.4 ± 11.3 years) and twelve chronic stroke patients (5 men, 7 women, aged 48.1 ± 11.1 years) with clinically significant right-sided motor impairment (mean FM-UE score of 27.6 ± 8.7) participated. The analysis employed the CONN toolbox to assess the association between motor tasks and VTA connectivity using psychophysiological interaction (PPI). Results: PPI analysis revealed motor-dependent changes in VTA connectivity, particularly with regions within the motor circuitry, cerebellum, and prefrontal cortex. Notably, stronger connectivity between the ipsilesional VTA and cerebellum was observed in healthy controls compared to chronic stroke patients, highlighting the importance of VTA-cerebellum interactions in motor function. Stroke patients' motor performance was associated with VTA modulation in areas related to both motor tasks and reward processing, emphasizing the role of self-reward processes in rehabilitation. Changes in VTA influence on motor circuitry were linked to improvements in motor performance resulting from rehabilitation. Discussion: Our findings underscore the potential of neuroimaging techniques in quantifying and predicting rehabilitation outcomes by examining self-reward processes. The observed associations between VTA connectivity and motor performance in both healthy and stroke-affected individuals emphasize the role of psychological factors, particularly self-reward, in the rehabilitation process. This study contributes valuable insights into the intricate interplay between reward circuits and motor function, highlighting the importance of addressing psychological dimensions in neurorehabilitation strategies.

Use of a Foot-Induced Digitally Controlled Resistance Device for Functional Magnetic Resonance Imaging Evaluation in Patients with Foot Paresis.

Neurological deficits from a stroke can result in long-term motor disabilities, including those that affect walking gait. However, extensive rehabilitation following stroke is typically time limited. Establishing predictive biomarkers to identify patients who may meaningfully benefit from additional physical therapy and demonstrate improvement is important to improve the patients' quality of life. Detection of neuroplastic remodeling of the affected region and changes in the activity patterns excited while performing suitable motor tasks could have valuable implications for chronic stroke recovery. This protocol describes the use of a digitally controlled, magnetic resonance-compatible foot-induced robotic device (MR_COFID) to present a personalized foot-motor task involving trajectory following to stroke-affected subjects with gait impairment during functional magnetic resonance imaging (fMRI). In the task, foot flexion is performed against bi-directional resistive forces, which are tuned to the subject's strength in both the dorsiflexion and plantar flexion directions, while following a visual metronome. fMRI non-invasively uses endogenous deoxyhemoglobin as a contrast agent to detect blood oxygenation level-dependent (BOLD) changes between the active and resting periods during testing. Repeated periodic testing can detect therapy-related changes in excitation patterns during task performance. The use of this technique provides data to identify and measure biomarkers that may indicate the likelihood of an individual benefitting from rehabilitation beyond that which is currently provided to stroke patients.

The Severity of Sensorimotor Tracts Degeneration May Predict Motor Performance in Chronic Stroke Patients, While Brain Structural Network Dysfunction May Not.

Although the relationship between corticospinal tract (CST) fiber degeneration and motor outcome after stroke has been established, the relationship of sensorimotor cortical areas with CST fibers has not been clarified. Also limited research has been conducted on how abnormalities in brain structural networks are related to motor recovery. To address these gaps in knowledge, we conducted a diffusion tensor imaging (DTI) study with 12 chronic stroke patients (CSPs) and 12 age-matched healthy controls (HCs). We compared fractional anisotropy (FA) and mean diffusivity (MD) in 60 CST segments using the probabilistic sensorimotor area tract template (SMATT). Least Absolute Shrinkage and Selection Operator (LASSO) regressions were used to select independent predictors of Fugl-Meyer upper extremity (FM-UE) scores among FA and MD values of SMATT regions. The Graph Theoretical Network Analysis Toolbox was used to assess the structural network of each subject's brain. Global and nodal metrics were calculated, compared between the groups, and correlated with FM-UE scores. Mann-Whitney U-tests revealed reduced FA values in CSPs, compared to HCs, in many ipsilesional SMATT regions and in two contralesional regions. Mean FA value of the left (L.) primary motor cortex (M1)/supplementary motor area (SMA) region was predictive of FM-UE score (P = 0.004). Mean MD values for the L. M1/ventral premotor cortex (PMv) region (P = 0.001) and L. PMv/SMA region (P = 0.001) were found to be significant predictors of FM-UE scores. Network efficiency was the only global metric found to be reduced in CSPs (P = 0.006 vs. HCs). Nodal efficiency of the L. hippocampus, L. parahippocampal gyrus, L. fusiform gyrus (P = 0.001), and nodal local efficiency of the L. supramarginal gyrus (P < 0.001) were reduced in CSPs relative to HCs. No graph metric was associated with FM-UE scores. In conclusion, the integrity of CSTs connected to M1, SMA, and PMv were shown to be independent predictors of motor performance in CSPs, while stroke-induced topological changes in the brain's structural connectome may not be. A sensorimotor cortex-specific tract template can refine CST degeneration data and the relationship of CST degeneration with motor performance.

Volumetric apparent diffusion coefficient histogram analysis of the testes in nonobstructive azoospermia: a noninvasive fingerprint of impaired spermatogenesis?

OBJECTIVES: To explore the association between testicular volumetric apparent diffusion coefficient (ADC) histogram analysis metrics and histologic categories in nonobstructive azoospermia (NOA). The role of ADC histogram analysis in predicting the presence of spermatozoa, prior to testicular sperm extraction (TESE), was also investigated. METHODS: Forty-one NOA men and 17 age-matched controls underwent scrotal MRI with diffusion-weighted imaging. Histogram analysis of ADC data of the whole testis was performed. Metrics including mean, standard deviation, median, mode, 25th percentile, 75th percentile, skewness, kurtosis, and entropy of volumetric ADC histograms were calculated. Nonparametric statistical tests were used to assess differences in ADC histogram parameters between NOA histologic categories (hypospermatogenesis, severe hypospermatogenesis, early maturation arrest, and Sertoli cell-only syndrome) and normal testes and, between NOA with positive and negative sperm retrieval. RESULTS: Normal testes had a lower mean, median, mode, 25th percentile (p < 0.001), and 75th percentile of ADC (p = 0.001), compared to NOA histologic phenotypes. NOA with hypospermatogenesis had a lower 25th percentile of ADC compared to NOA with severe hypospermatogenesis. Regression analysis revealed that the 25th percentile of ADC had a moderately negative correlation with NOA histologic phenotype. The median ADC proved the most significant metric (p = 0.007) to predict the presence of sperm. CONCLUSIONS: Testicular volumetric ADC histogram parameters may contribute in the identification of the subpopulation of NOA men with a specific type of spermatogenic arrest. KEY POINTS: • Volumetric ADC histogram analysis metrics may be used as noninvasive markers of impaired spermatogenesis in nonobstructive azoospermia. • The 25th percentile of ADC proved useful in discriminating between NOA testes with hypospermatogenesis and severe hypospermatogenesis. • The median ADC proved the most significant parameter to predict the presence of viable spermatozoa prior to TESE.

Proton MR Spectroscopy in Assessing the Biochemical Milieu of Human Testes.

Proton magnetic resonance spectroscopy (MRS), considered a connection between metabolism and anatomic and functional information provided by standard MRI, gives information on various tissue metabolites and their pathologic changes. Recently, proton MRS has been added as an adjunct tool to the multiparametric protocol of scrotal MRI, providing a new insight into the extremely complex biochemical milieu of normal and abnormal testes. This article reviews proton MR spectra of normal testes, showing age and bilateralism dependence. Disturbances of various metabolic pathways in testes of infertile men resulting in alterations of metabolite peaks are discussed. Preliminary data on proton MR spectra of testicular mass lesions are presented. LEVEL OF EVIDENCE: 5. TECHNICAL EFFICACY STAGE: 5.

A magnetic resonance imaging study in etiology of nonobstructive azoospermia.

BACKGROUND: Testicular magnetic resonance imaging parameters, including apparent diffusion coefficient, fractional anisotropy, magnetization transfer ratio, and normalized metabolite concentrations represent useful noninvasive fingerprints of nonobstructive azoospermia. Nonobstructive azoospermia etiology might correlate with the spermatogenesis status. OBJECTIVES: To assess the possible association between apparent diffusion coefficient, fractional anisotropy, magnetization transfer ratio, and normalised metabolite concentrations with nonobstructive azoospermia etiology. MATERIALS AND METHODS: This retrospective study included 48 consecutive men with nonobstructive azoospermia and 18 age-matched controls. All participants underwent scrotal magnetic resonance imaging. The testicular apparent diffusion coefficient, fractional anisotropy, magnetization transfer ratio, and normalized metabolite concentrations were calculated. nonobstructive azoospermia men were classified into three groups, based on etiology: group 1, idiopathic; group 2, genetic causes; and group 3, non-genetic causes. Parametric and nonparametric statistical tests were used to evaluate differences in magnetic resonance imaging parameters between nonobstructive azoospermia groups and normal testes (group 4). Regression analysis was performed to assess the most predictive magnetic resonance imaging factor of nonobstructive azoospermia etiology. RESULTS: Differences in mean apparent diffusion coefficient (p < .001), fractional anisotropy (p < .001), magnetization transfer ratio (p < .001), and normalized concentrations of total choline (p = .005), glucose (p = .012), myo-inositol (p = .024), and lipids (p = .010) were observed among groups. Regression analysis failed to identify the most discriminating magnetic resonance imaging feature for nonobstructive azoospermia etiology. DISCUSSION AND CONCLUSION: Apparent diffusion coefficient, fractional anisotropy, magnetization transfer ratio, and normalized concentrations of total choline, glucose, myo-inositol, and lipids are helpful in discriminating nonobstructive azoospermia etiology. Magnetic resonance imaging may provide useful, noninvasive information on the microstructural and biochemical milieu of nonobstructive azoospermia testes.

Structural and functional brain connectivity in moderate-late preterm infants with low-grade intraventricular hemorrhage.

PURPOSE: Brain functional connectivity (FC) changes and microstructural abnormalities are reported in infants born moderate and late preterm (MLPT). We evaluated the effect of low-grade (grades I, II) intraventricular hemorrhage (IVH) in MLPT babies on brain structural connectivity (SC) and FC. METHODS: Babies born MLPT between January 2014 and May 2017 underwent brain ultrasound (US) at 72 h and 7 days after birth, and MRI at around term equivalent. The MRI protocol comprised T1- and T2-weighted sequences, diffusion tensor imaging (DTI), and resting-state functional MRI (fMRI). SC and FC were assessed using graph analysis. RESULTS: Of 350 MLPT neonates, 15 showed low-grade IVH on US at 72 h, for which brain MRI was available in 10. These 10 infants, with mean gestational age (GA) 34.0 ± 0.8 weeks, comprised the study group, and 10 MLPT infants of mean GA 33.9 ± 1.1 weeks, with no abnormalities on brain US and MRI, were control subjects. All study subjects presented modularity, small world topology, and rich club organization for both SC and FC. The patients with low-grade IVH had lower FC rich club coefficient and lower SC betweenness centrality in the left frontoparietal operculum, and lower SC rich club coefficient in the right superior orbitofrontal cortex than the control subjects. CONCLUSIONS: Topological and functional properties of mature brain connectivity are present in MLPT infants. IVH in these infants was associated with structural and functional abnormalities in the left frontoparietal operculum and right orbitofrontal cortex, regions related to language and cognition.

Peak Activation Shifts in the Sensorimotor Cortex of Chronic Stroke Patients Following Robot-assisted Rehabilitation Therapy.

BACKGROUND: Ischemic stroke is the most common cause of complex chronic disability and the third leading cause of death worldwide. In recovering stroke patients, peak activation within the ipsilesional primary motor cortex (M1) during the performance of a simple motor task has been shown to exhibit an anterior shift in many studies and a posterior shift in other studies. OBJECTIVE: We investigated this discrepancy in chronic stroke patients who completed a robot-assisted rehabilitation therapy program. METHODS: Eight chronic stroke patients with an intact M1 and 13 Healthy Control (HC) volunteers underwent 300 functional magnetic resonance imaging (fMRI) scans while performing a grip task at different force levels with a robotic device. The patients were trained with the same robotic device over a 10-week intervention period and their progress was evaluated serially with the Fugl-Meyer and Modified Ashworth scales. Repeated measure analyses were used to assess group differences in locations of peak activity in the sensorimotor cortex (SM) and the relationship of such changes with scores on the Fugl-Meyer Upper Extremity (FM UE) scale. RESULTS: Patients moving their stroke-affected hand had proportionally more peak activations in the primary motor area and fewer peak activations in the somatosensory cortex than the healthy controls (P=0.009). They also showed an anterior shift of peak activity on average of 5.3-mm (P<0.001). The shift correlated negatively with FM UE scores (P=0.002). CONCLUSION: A stroke rehabilitation grip task with a robotic device was confirmed to be feasible during fMRI scanning and thus amenable to be used to assess plastic changes in neurological motor activity. Location of peak activity in the SM is a promising clinical neuroimaging index for the evaluation and monitoring of chronic stroke patients.

Vitamin D Deficiency as a Risk Factor for Myocardial Ischemia.

Background and Objectives: Vitamin D (Vit D) deficiency has been implicated in various conditions, including cardiovascular disease. The purpose of this retrospective study was to investigate the incidence of patients with myocardial ischemia in relation to their serum levels of vitamin D. Materials and Methods: A 64-month search (January 2016 to April 2021) in our database of the Nuclear Medicine Laboratory revealed 113 patients who had both myocardial perfusion imaging with single photon emission computed tomography (MPI SPECT) and Vit D measurements. MPI SPECT obtained myocardial images during both stress (summed stress score, SSS) and rest (summed rest score, SRS). Abnormal MPI SPECT was when the SSS was ≥4. Vit D was determined by radioimmunoassay (RIA). Patients with Vit D values <10 ng/mL, 10-29 ng/mL and ≥30 ng/mL were defined as having a deficiency, insufficiency and sufficiency, respectively. Results: Among patients, 46/113 (40.7%) were male and 67/113 (59.3%) were female. Abnormal MPI was found in 58/113 (51.3%) patients. Vit D deficiency was noted in 20/113 (17.7%) patients, insufficiency in 86/113 (76.1%) patients, and normal Vit D was noted in only 7/113 (6.2%) patients. Sixteen of the 20 patients (80%) with Vit D deficiency, and 38/86 (44.2%) with insufficiency had an abnormal MPI SPECT. In contrast, only 1/7 (14.3%) patients with sufficient Vit D levels had an abnormal MPI SPECT. The Mann-Whitney U-test showed that ischemia reduced the values of Vit D. Correlation analysis showed a negative association of Vit D levels with SSS (rho = -0.232, p = 0.014) and SRS (rho = -0.250, p = 0.008). Further evaluation with a Vit D cut off 20 ng/mL retrieved no statistical significance. Finally, Vit D and gender were independently associated with myocardial ischemia. Conclusions: Low Vit D levels may represent a risk factor for myocardial ischemia.

Improving motor function after chronic stroke by interactive gaming with a redesigned MR-compatible hand training device.

New rehabilitation strategies enabled by technological developments are challenging the prevailing concept of there being a limited window for functional recovery after stroke. In this study, we examined the utility of a robot-assisted therapy used in combination with a serious game as a rehabilitation and motor assessment tool in patients with chronic stroke. We evaluated 928 game rounds from 386 training sessions of 8 patients who had suffered an ischemic stroke affecting middle cerebral artery territory that incurred at least 6 months prior. Motor function was assessed with clinical motor scales, including the Fugl-Meyer upper extremity (FM UE) scale, Action Research Arm Test, Modified Ashworth scale and the Box and Blocks test. Robotic device output measures (mean force, force-position correlation) and serious game score elements (collisions, rewards and total score) were calculated. A total of 2 patients exhibited a marginal improvement after a 10-week training protocol according to the FM UE scale and an additional patient exhibited a significant improvement according to Box and Blocks test. Motor scales showed strong associations of robotic device parameters and game metrics with clinical motor scale scores, with the strongest correlations observed for the mean force (0.677<Ρ<0.869), followed by the number of collisions (-0.670<Ρ<-0.585). Linear regression analysis showed that these indices were independent predictors of motor scale scores. In conclusion, a robotic device linked to a serious game can be used by patients with chronic stroke and induce at least some clinical improvements in motor performance. Robotic device output parameters and game score elements associate strongly with clinical motor scales and have the potential to be used as predictors in models of rehabilitation progress.

Machine Learning Algorithms and Statistical Approaches for Alzheimer's Disease Analysis Based on Resting-State EEG Recordings: A Systematic Review.

Alzheimer's Disease (AD) is a neurodegenerative disorder and the most common type of dementia with a great prevalence in western countries. The diagnosis of AD and its progression is performed through a variety of clinical procedures including neuropsychological and physical examination, Electroencephalographic (EEG) recording, brain imaging and blood analysis. During the last decades, analysis of the electrophysiological dynamics in AD patients has gained great research interest, as an alternative and cost-effective approach. This paper summarizes recent publications focusing on (a) AD detection and (b) the correlation of quantitative EEG features with AD progression, as it is estimated by Mini Mental State Examination (MMSE) score. A total of 49 experimental studies published from 2009 until 2020, which apply machine learning algorithms on resting state EEG recordings from AD patients, are reviewed. Results of each experimental study are presented and compared. The majority of the studies focus on AD detection incorporating Support Vector Machines, while deep learning techniques have not yet been applied on large EEG datasets. Promising conclusions for future studies are presented.

A preliminary study of the biochemical environment of infertile testes with clinical varicocele.

PURPOSE: To investigate the role of proton magnetic resonance spectroscopy. (1H-MRS) in the assessment of the biochemical environment of testes in infertile men with clinical varicocele. METHODS: In this prospective IRB approved study, 13 infertile men with clinical varicocele and 11 age-matched controls were assessed. 1H-MRS was performed using a single voxel point-resolved spectroscopy (PRESS) sequence with TR/TE: 2000/25 ms. Normalized metabolite concentrations, defined as ratios of the calculated metabolite concentrations relative to total creatine (tCr) concentration were compared between infertile testes with clinical varicocele and normal testes using nonparametric statistical tests. Logistic regression analysis was performed to assess the most significant predictor for the diagnosis of varicocele. RESULTS: Several metabolic peaks were found in both infertile testes with clinical varicocele and normal testes. Most prominent peaks were the following: total choline (tCho), tCr, myo-inositol (mI), Glx, and total lipids and macromolecules resonating at 0.9 ppm (TLM09), 1.3 ppm (TLM13) and 2.0 ppm (TLM20). Lower normalized concentrations of tCho (P = 0.001), mI (P = 0.012), Glx (P = 0.011), TLM09 (P = 0.027), TLM13 (P = 0.035) and TLM20 (P = 0.021) were found in infertile testes with clinical varicocele compared with normal men. Total Cho proved the most significant predictor for the diagnosis of clinical varicocele (P = 0.001). CONCLUSIONS: 1H-MR spectra of infertile testes with clinical varicocele showed decrease in normalized concentrations of tChol, ml, Glx and lipids. 1H-MRS of the testes might be used as a noninvasive marker of deranged spermatogenesis in infertile men with clinical varicocele.

In vivo biochemical investigation of spermatogenic status: 1H-MR spectroscopy of testes with nonobstructive azoospermia.

OBJECTIVES: To evaluate the biochemical milieu in testes with nonobstructive azoospermia (NOA) by using proton MR spectroscopy (1H-MRS) in detecting differences in testicular metabolites between histological stages of NOA and in assessing the possible presence of spermatozoa before microdissection testicular sperm extraction (mTESE). METHODS: Forty-nine NOA men and fifty age-matched controls were included in this prospective study. A single-voxel point-resolved spectroscopy sequence with TR/TE (2000/25 ms) was used. NOA testes were classified using the higher Johnsen score (hJS) (group 1, hJS ≥ 8; and group 2, hJS < 8). Nonparametric statistical tests were used to assess differences in normalized metabolite concentrations, defined as ratios of the metabolite concentrations versus creatine concentration between (a) NOA and controls, (b) NOA groups, and (c) NOA with positive and negative sperm retrieval. RESULTS: Normalized concentrations of total choline (median 0.396 vs 1.09 mmol/kg, p = 0.002), myo-inositol (median 1.985 vs 3.19 mmol/kg, p = 0.002), and total lipids and macromolecules (TLM) resonating at 0.9 ppm (median 0.962 vs 2.43 mmol/kg, p = 0.024), 1.3 ppm (median 4.88 vs 10.7 mmol/kg, p = 0.043), and 2.0 ppm (median 2.33 vs 5.96 mmol/kg, p = 0.007) were reduced in NOA testes compared with controls. Decreased concentrations of TLM 2.0 (median 3.755 vs 0.436 mmol/kg, p = 0.043) were found in group 2 compared with group 1. Increased normalized concentrations of glutamate were observed in NOA testes with failed sperm retrieval (median 0.321 vs 0.000 mmol/kg, p = 0.028). CONCLUSIONS: 1H-MRS provides metabolic information about the testis in NOA patients and assesses spermatogenic status before mTESE. KEY POINTS: • NOA testes differed from age-matched controls, in terms of reduced normalized concentrations of tChol, mI, and lipids. • TLM 2.0 peaks were found useful in the identification of NOA testes with the presence of foci of advanced spermatogenesis up to the haploid gamete stage. • Glu proved a reliable metabolic signature of spermatogenesis in NOA population by assessing the possible presence of sperm after mTESE.