Longitudinal Imaging Research Articles

Longitudinal Imaging Biomarkers Correlate with Progressive Motor Deficit in the Mouse Model of Charlevoix-Saguenay Ataxia.

In autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) disease, severity and age of onset vary greatly, hindering to objectively measure and predict clinical progression. Thickening of the retinal nerve fiber layer is distinctive of ARSACS patients, as assessed by optical coherence tomography, whereas conventional brain magnetic resonance imaging findings include both supratentorial and infratentorial changes. Because longitudinal imaging studies in ARSACS patients are not available to define these changes as biomarkers of disease progression, we aimed to address this issue in the ARSACS mouse model. We performed longitudinal retinal OCT and brain MRI in the Sacs-/- ARSACS mouse model, alongside motor and coordination assessment in the beam walking test. We also investigated visual function and the molecular mechanisms underlying RNFL increased thickness by histology and immunofluorescence. We demonstrated that RNFL thickening by OCT gradually increases in the early stages of pathology in the Sacs-/- mouse model, reflecting the progression of motor impairment, and later reaches a plateau when thinning of the posterior corpus callosum becomes detectable by MRI. Mechanistically, we unveiled that RNFL thickening is associated with aberrant accumulation of non-phosphorylated neurofilament H and glial fibrillary acidic protein. We also uncovered mild signs of myelin pathology coherent with increased latency of visual evoked potentials, and altered retinal activation by photopic electroretinography. We show that both RNFL thickening and MRI changes may represent biomarkers of disease progression in the Sacs-/- mouse model. Our data gathers knowledge instrumental to clinical studies, holding potential as readout for treatment efficacy. ANN NEUROL 2024.

Ultrasound-based radiomics to predict the volume reduction rate of benign thyroid nodules after microwave ablation.

To evaluate the predictive power of ultrasound-based radiomics models for benign thyroid nodules with a volume reduction rate (VRR) of < or ≥75% at 12 months after microwave ablation. A retrospective study was conducted on 194 individuals with benign thyroid nodules who received ultrasound-guided microwave ablation between November 2019 and June 2023. The clinical and ultrasound features, including age, gender, volume, echogenicity, duration of ablation, and so on were analysed by t-test or chi-square test. Radiomics features were extracted from longitudinal and transverse ultrasound images of the nodules. The features were selected using methods such as least absolute shrinkage and selection operator (LASSO). Radiomics models were established using longitudinal, transverse, and longitudinal + transverse ultrasound images to predict the VRR of benign thyroid nodules after ablation. Decision curve analysis (DCA) and receiver operating characteristic (ROC) curve analysis were used to assess the models' performance. At 12 months following ablation, the VRR of the nodules was 77.8 ± 19.4% (7.4-98.8%). Statistical analysis revealed that the duration of ablation and the proportion of liquid extracted were significantly correlated with the 12-month VRR (P <0.05). In the radiomics models, Logistic Regression (LR) performed the best. In the training cohorts, the area under the curve (AUC) for the longitudinal, transverse, and combined groups were 0.935, 0.800, and 0.937. The AUC values in the test cohort were 0.820, 0.844, and 0.917. The radiomics models established based on pre-ablation ultrasound images showed good predictive efficacy for the VRR of nodules at 12 months following ablation. The predictive efficacy is best in the combined group. With the models, we can preoperatively predict patients' prognoses and thereby determine whether to proceed with ablation therapy.

Utility of icobrain for brain volumetry in multiple sclerosis clinical practice

BackgroundFew studies on multiple sclerosis (MS) have explored the variability of percentage brain volume change (PBVC) measurements obtained from different clinical MRIs. In a retrospective multicentre cohort study, we quantified the variability of annualised PBVC in clinical MRIs. MethodsClinical MRIs of relapse-onset MS patients were assessed by icobrain. Volumetric data were analysed on same-scanner and different-scanner MRI pairs if they passed quality control criteria. Alignment similarity between two images had to be comparable to same-scanner scan-rescan images. ResultsOf 6826 MRIs, 85% had appropriate volumetric sequences and 4446 serial MRI pairs were analysed. 3334 (75%) MRI pairs from 1207 patients met the inclusions. The PBVC of included MRI pairs showed variance of 0.78% for same-scanner pairs and 0.80% for different-scanner pairs. Further selection of included MRI pairs with the best variance resulted in 1885 (42%) MRI pairs with PBVC variance of 0.34%. Excluded MRI pairs with poor alignment similarity had variances of 2.97% for same-scanner pairs and 20.79% for different-scanner pairs. ConclusionIcobrain should be utilised for PBVC determination only on selected MRIs with the best alignment similarity. Applying strict selection criteria for the included MRI pairs and longitudinal imaging on the same scanner remain mandatory to reduce PBVC variability.

Metalens design with broadband achromatic and Longitudinal High-Tolerance Imaging

Metalens design with broadband achromatic and Longitudinal High-Tolerance Imaging

Connectivity, Pathology, and ApoE4 Interactions Predict Longitudinal Tau Spatial Progression and Memory.

Tau pathology spread into neocortex indicates a transition from healthy aging to Alzheimer's disease (AD). Connectivity between tau epicenters and later accumulating regions of cortex has been proposed as a mechanism of tau spread, but how this relationship changes with greater AD pathology burden or genotype is not understood. We investigated tau accumulation in two key regions, precuneus and inferior temporal cortex, using resting state functional connectivity (rsFC) and longitudinal PET imaging from a multicohort sample of cognitively unimpaired older adults. We examined how baseline tau PET, Aβ PET, and ApoE4 genotype status interact with rsFC between hippocampus and these downstream regions to predict rate of tau accumulation in neocortex. We found that the 3-way interaction between connectivity, baseline tau, and baseline Aβ or ApoE4 status was associated with neocortical tau accumulation in precuneus and inferior temporal cortex. In addition, baseline tau, Aβ, and ApoE4 status also moderated the association between connectivity and rate of memory decline. Together, these results suggest that the extent and distribution of future tau accumulation may be predicted by the interaction of baseline connectivity, AD pathology, and genetic risk.

Bone Regrowth After Frontal Burr Hole Craniostomy: Natural History of 14-mm and 20-mm Burr Holes and Implications for Postoperative Trans-Burr Hole Ultrasound

BACKGROUND AND OBJECTIVE: Burr hole craniostomy is performed for ventriculoperitoneal shunt insertion and endoscopic third ventriculostomy in patients with cerebrospinal fluid disorders. These burr holes are increasingly being used as windows for postoperative ultrasound, an investigational alternative to computed tomography or MRI for follow-up imaging of ventricular caliber. However, bone regrowth reduces ultrasound visibility, and little is known about burr hole regrowth rates in adults. Our study evaluates burr hole regrowth patterns and implications for transcranial ultrasound imaging. METHODS: We retrospectively analyzed 101 consecutive patients who had frontal burr hole craniostomy for new ventriculoperitoneal shunt insertion or endoscopic third ventriculostomy over a 3-year period. A mix of standard 14-mm burr holes and expanded 20-mm burr holes were used. Burr hole bone regrowth was assessed using serial follow-up computed tomography scans. Linear and logistic regression analyses examined if bone regrowth correlated with any clinical variables. RESULTS: There was wide variability in rate and degree of burr hole regrowth. The average percentage closure was 25% at 6 months, with minimal additional closure over the following 18 months. The mean residual diameter for 14-mm and 20-mm burr holes stabilized around 9.4 mm and 15.4 mm, respectively. Bone regrowth was not associated with patient characteristics, including age, sex, skull thickness, or etiology of cerebrospinal fluid disorder. Rate of bone regrowth was similar between both cohorts. CONCLUSION: Bone regrowth after burr hole craniostomy is common, even in elderly patients, occurring rapidly within the first 6 to 12 months and subsequently stabilizing. It is frequently severe enough to restrict ultrasound visualization. Regrowth could not be predicted with any investigated variables, so uniform techniques are needed to block regrowth to allow for longitudinal ultrasound imaging, such as full-thickness cylindrical burr hole implants.

Mapping Longitudinally Consistent Intrinsic Connectivity Networks in Macaque Brain via Longitudinal Sparse Dictionary Learning

Mapping consistent longitudinal intrinsic connectivity networks (ICNs) is crucial for understanding brain functional development over various life stages. However, achieving consistent longitudinal ICNs has been challenging due to the lack of methodologies that maintain temporal consistency. To address this gap, we introduce an innovative approach named Longitudinal Sparse Dictionary Learning (LSDL). This method utilizes an additional Frobenius norm to bridge gaps between consecutive ICNs, facilitating the continuous transfer of the learned feature matrix to subsequent stages. Moreover, Matrix Backpropagation (MBP) is employed to effectively mitigate potential accumulative errors. Our validation results demonstrate that LSDL can successfully extract 21 consistent longitudinal ICNs in macaque brains. In comparative empirical evaluations with established methodologies, Fast Independent Component Analysis (FICA) and Sparse Dictionary Learning (SDL), LSDL showcases superior efficacy in modeling longitudinal functional Magnetic Resonance Imaging (fMRI) data. This approach opens new avenues for research into developmental brain dynamics and neurodegenerative disorders, providing a robust framework for tracking the evolution of brain connectivity over time.

Lipid-related radiomics of low-echo carotid plaques is associated with diabetic stroke and non-diabetic coronary heart disease.

Carotid plaque radiomics-included models have increased the predictive capacity of cardiovascular risk, but the radiomic features of these models were inconsistent in previous studies. Lipids could be used to select the most important radiomic feature. A retrospective case‒control study was performed in 153 diabetic and 76 non-diabetic patients with carotid plaque detected by ultrasound. Cerebro-cardiovascular disease (CCD), comprising coronary heart disease (CHD) and stroke, was the primary outcome. Clinical variables and radiomic features of longitudinal carotid plaque images were collected. Principal component analyses were used to compare the power of radiomic and lipid features in discrimination between diabetes, CCD patients, and their opposites. Partial least square regression, logistic regression analyses, and least absolute shrinkage and selection operator (LASSO) regression were performed for high-risk radiomic features. The diagnostic capacity of the models was evaluated. PCA based on radiomics or lipids did not show good discrimination of diabetes, CCD, and their opposites. There were 6 overlapping radiomic features associated with lipid profiles, but only original_firstorder_Mean was negatively associated with diabetic stroke [adjusted OR = 0.468 (0.243-0.902), P = 0.023] and nondiabetic CHD [adjusted OR = 0.311 (0.123-0.783), P = 0.013]. The associations remained independent in the LASSO regression models (β=-0.032 for diabetic stroke, and - 0.026 for non-diabetic CHD). The diagnostic capacity of lipid-related radiomics for diabetic stroke (0.556 to 0.688) and non-diabetic CHD (0.690 to 0.783) was increased by the combination of these clinical variables. Carotid plaque radiomics is associated with lipids and stroke in diabetes, and quantitative features are useful for therapeutic guidance and cardiovascular risk evaluation in clinical use.

Intravoxel incoherent motion imaging in stroke infarct core and penumbra is related to long-term clinical outcome

Intravoxel incoherent motion (IVIM) imaging, a contrast agent-free magnetic resonance imaging technique, enables the evaluation of microvascular perfusion abnormalities in acute stroke. Prior research reported reduced IVIM values within the infarct core in acute stroke. However, findings concerning IVIM characteristics in the penumbra have been mixed and the relationship between IVIM and clinical outcomes remains unknown. We employed a longitudinal multimodal imaging approach for ischemic stroke patients (n analyzed=24; pre-/post-treatment and 90-day post-stroke assessments) including IVIM, diffusion-weighted, and contrast-enhanced perfusion-weighted imaging. We evaluated IVIM in relevant stroke areas after endovascular treatment. Reduced post-treatment IVIM perfusion fraction in infarct core and recanalized penumbra was associated with poorer functional recovery at 90-days post-stroke (NIH Stroke Scale [NIHSS]; r=-0.64 and r=-0.69). Including IVIM perfusion fraction increased the explained variance of NIHSS from 42% up to 83% compared to well-known prognostic factors core volume and patient age. Additionally, IVIM perfusion fraction was reduced in the core and recanalized penumbra compared to contralateral healthy tissue, suggesting impaired microvascular reperfusion after endovascular treatment. In conclusion, IVIM characteristics of the infarct core and recanalized penumbra are strong prognostic factors for long-term outcome in stroke patients and IVIM shows promise for characterizing microvascular perfusion in relevant stroke areas.

Longitudinal markers of cognitive procedural learning in fronto-striatal circuits and putative effects of a BDNF plasticity-related variant

Procedural learning and automatization have widely been studied in behavioral psychology and typically involves a rapid improvement, followed by a plateau in performance throughout repeated training. More recently, brain imaging studies have implicated frontal-striatal brain circuits in skill learning. However, it is largely unknown whether frontal-striatal activation during skill learning and behavioral changes follow a similar learning curve pattern. To address this gap in knowledge, we performed a longitudinal brain imaging study using a procedural working memory (pWM) task with repeated measurements across two weeks to map the temporal dynamics of skill learning. We additionally explored the effect of the BDNF Val66Met polymorphism, a common genetic polymorphism impacting neural plasticity, to further inform the relevance of the identified neural markers. We used linear and exponential modeling to characterize procedural learning by means of learning curves on the behavioral and brain functional level. We show that repeated training led to an exponential decay in a distributed set of brain regions including fronto-striatal circuits, which paralleled the exponential improvement in task performance. In addition, we show that both behavioral and neurofunctional readouts were sensitive to the BDNF Val66Met polymorphism, suggesting less efficient learning in 66Met-allele carriers along with protracted signal decay in frontal and striatal brain regions. Our results extend existing literature by showing the temporal relationship between procedural learning and frontal-striatal brain function and suggest a role of BDNF in mediating neural plasticity for establishing automatized behavior.

Quantifying UV-induced photo-damage for longitudinal live-cell imaging applications of deep-UV microscopy

Quantifying UV-induced photo-damage for longitudinal live-cell imaging applications of deep-UV microscopy

Evaluation of Left Ventricular Systolic Functions of Patients with Exaggerated High Blood Pressure Response to Treadmill Exercise Test with Two-Dimensional Longitudinal Strain Imaging.

An exaggerated hypertensive response (EHR) during exercise is linked to increased cardiovascular risk and mortality. This study aims to assess structural and functional cardiac changes, along with subclinical myocardial damage, using transthoracic echocardiography (ECHO) and 2D longitudinal strain analysis in patients showing a hypertensive response to treadmill exercise. Patients without known chronic diseases, presenting to the Cardiology Department at Health Sciences University Gülhane Training and Research Hospital, were divided into 2 groups based on their blood pressure response during treadmill exercise: exaggerated hypertensive response (EHR, n = 42) and normal response (control, n = 44). Left ventricular longitudinal strain was assessed using transthoracic echocardiography, and global longitudinal strain (GLS) was calculated as the average from all segments. Data analysis was performed using SPSS 26. No significant differences were found between the groups regarding baseline demographic and laboratory parameters (P > .05 for all). However, the EHR group exhibited significantly higher interventricular septum thickness, mitral A velocity, and mitral annulus velocity (a'), while mitral annulus velocity (e') was significantly lower (P < .05 for all). Additionally, left ventricular (LV) mass index, left atrial volume index, mitral E/e' ratio, deceleration time, and relative wall thickness (RWT) were higher in the EHR group, while the mitral E/A ratio was lower (P < .05 for all). The GLS was also significantly lower in the EHR group (P < .05). Left ventricular geometry parameters, such as LV mass index and RWT, and GLS findings indicating subclinical cardiac damage, were significantly altered in the EHR group, suggesting a higher risk of LV hypertrophy and myocardial dysfunction.

Hippocampal atrophy over two years in relation to tau, amyloid-β and memory in older adults

In this longitudinal brain imaging study, we aimed to characterize hippocampal tau accumulation and subfield atrophy relative to cortical amyloid-β and memory performance. We measured tau-PET in regions associated with Braak stages I to VI, global amyloid-PET burden, hippocampal subfield volumes and memory assessments from 173 participants aged 55–85. Eighty-six of these participants were tested again two years later. Tau-PET change in the Braak II region, corresponding to the hippocampus and the entorhinal cortex, was significantly associated with the cornu ammonis 1 (CA1) atrophy and memory score. This CA1 atrophy did not significantly mediate the association between tau and memory, nor did global amyloid-PET burden correlate with tau-PET changes in the Braak II region. Longitudinal hippocampal tau accumulation is amyloid-β-independent and co-localized with subfield atrophy. As tau-associated memory decline seems to be independent from hippocampal atrophy, other mechanisms could contribute to the deficit.

Imaging the large-scale and cellular response to focal traumatic brain injury in mouse neocortex.

Traumatic brain injury (TBI) affects neural function at the local injury site and also at distant, connected brain areas. However, the real-time neural dynamics in response to injury and subsequent effects on sensory processing and behaviour are not fully resolved, especially across a range of spatial scales. We used in vivo calcium imaging in awake, head-restrained male and female mice to measure large-scale and cellular resolution neuronal activation, respectively, in response to a mild/moderate TBI induced by focal controlled cortical impact (CCI) injury of the motor cortex (M1). Widefield imaging revealed an immediate CCI-induced activation at the injury site, followed by a massive slow wave of calcium signal activation that travelled across the majority of the dorsal cortex within approximately 30s. Correspondingly, two-photon calcium imaging in the primary somatosensory cortex (S1) found strong activation of neuropil and neuronal populations during the CCI-induced travelling wave. A depression of calcium signals followed the wave, during which we observed the atypical activity of a sparse population of S1 neurons. Longitudinal imaging in the hours and days after CCI revealed increases in the area of whisker-evoked sensory maps at early time points, in parallel to decreases in cortical functional connectivity and behavioural measures. Neural and behavioural changes mostly recovered over hours to days in our M1-TBI model, with a more lasting decrease in the number of active S1 neurons. Our results in unanaesthetized mice describe novel spatial and temporal neural adaptations that occur at cortical sites remote to a focal brain injury.

A Systematic Review on the Use of Registration-Based Change Tracking Methods in Longitudinal Radiological Images.

Registration is the process of spatially and/or temporally aligning different images. It is a critical tool that can facilitate the automatic tracking of pathological changes detected in radiological images and align images captured by different imaging systems and/or those acquired using different acquisition parameters. The longitudinal analysis of clinical changes has a significant role in helping clinicians evaluate disease progression and determine the most suitable course of treatment for patients. This study provides a comprehensive review of the role registration-based approaches play in automated change tracking in radiological imaging and explores the three types of registration approaches which include rigid, affine, and nonrigid registration, as well as methods of detecting and quantifying changes in registered longitudinal images: the intensity-based approach and the deformation-based approach. After providing an overview and background, we highlight the clinical applications of these methods, specifically focusing on computed tomography (CT) and magnetic resonance imaging (MRI) in tumors and multiple sclerosis (MS), two of the most heavily studied areas in automated change tracking. We conclude with a discussion and recommendation for future directions.

Trajectories of human brain functional connectome maturation across the birth transition.

Understanding the sequence and timing of brain functional network development at the beginning of human life is critically important from both normative and clinical perspectives. Yet, we presently lack rigorous examination of the longitudinal emergence of human brain functional networks over the birth transition. Leveraging a large, longitudinal perinatal functional magnetic resonance imaging (fMRI) data set, this study models developmental trajectories of brain functional networks spanning 25 to 55 weeks of post-conceptual gestational age (GA). The final sample includes 126 fetal scans (GA = 31.36 ± 3.83 weeks) and 58 infant scans (GA = 48.17 ± 3.73 weeks) from 140 unique subjects. In this study, we document the developmental changes of resting-state functional connectivity (RSFC) over the birth transition, evident at both network and graph levels. We observe that growth patterns are regionally specific, with some areas showing minimal RSFC changes, while others exhibit a dramatic increase at birth. Examples with birth-triggered dramatic change include RSFC within the subcortical network, within the superior frontal network, within the occipital-cerebellum joint network, as well as the cross-hemisphere RSFC between the bilateral sensorimotor networks and between the bilateral temporal network. Our graph analysis further emphasized the subcortical network as the only region of the brain exhibiting a significant increase in local efficiency around birth, while a concomitant gradual increase was found in global efficiency in sensorimotor and parietal-frontal regions throughout the fetal to neonatal period. This work unveils fundamental aspects of early brain development and lays the foundation for future work on the influence of environmental factors on this process.

Interhypothalamic adhesions: prevalence, structure, and location-based classification map in pediatric patients undergoing MRI.

Interhypothalamic adhesions (IHAs) have been reported only in the pediatric population, with unknown prevalence and histological composition. We aim to demonstrate their prevalence, assess their persistence through longitudinal imaging, classify IHAs by anatomical distribution, explore their structure, and report associated pathologies. A retrospective review was conducted on consecutive pediatric brain MRI studies obtained between January 2012, and December 2013. The presence of an IHA was only confirmed when observed on at least two planes. For each IHA, cross-sectional area was calculated, and signal intensities were measured at the center on sagittal T2WIs. Signal intensities were also measured in both cerebral white matter and gray matter for normalization and comparison. Patient demographics and clinical information were collected from electronic charts. Out of 1550 patients (0-17.9 years), 33 (19 males, 14 females) had an IHA, resulting in a 2.13% prevalence. Follow-up images were available for 19 IHA-positive patients, and IHAs were again seen in 92% of the follow-up scans (71/77). Normalized IHA signal highly correlated with normalized gray matter signal (r = 0.83, P < 0.001), but not with normalized white matter signal (r = -0.16, p = 0.494). Common co-occurring pathologies included hydrocephalus (n = 9), prematurity (n = 8), and corpus callosum abnormalities (n = 7). All type 3 IHAs (3/3) were accompanied by pituitary pathologies. IHAs have a prevalence of 2.13% in our cohort, and the majority persist in longitudinal studies. They showed gray matter signal intensity and Type 3 IHAs exclusively accompanied pituitary abnormalities.

Small-molecule inhibitors of the CD40-CD40L costimulatory interaction are effective in pancreatic islet transplantation and prevention of type 1 diabetes models.

As part of our work to develop small-molecule inhibitors (SMIs) of the CD40-CD40L(CD154) costimulatory protein-protein interaction, here, we describe the ability of two of our most promising SMIs, DRI-C21041 and DRI-C21095, to prolong the survival and function of islet allografts in two murine models of islet transplantation (under the kidney capsule and in the anterior chamber of the eye) and to prevent autoimmune type 1 diabetes (T1D) onset in NOD mice. In both transplant models, a significant portion of islet allografts (50%-80%) remained intact and functional long after terminating treatment, suggesting the possibility of inducing operational immune tolerance via inhibition of the CD40-CD40L axis. SMI-treated mice maintained the structural integrity and function of their islet allografts with concomitant reduction in immune cell infiltration as evidenced by direct longitudinal imaging in situ. Furthermore, in female NODs, three-month SMI treatment reduced the incidence of diabetes from 80% to 60% (DRI-C21041) and 25% (DRI-C21095). These results (i) demonstrate the susceptibility of this TNF superfamily protein-protein interaction to small-molecule inhibition, (ii) confirm the in vivo therapeutic potential of these SMIs of a critical immune checkpoint, and (iii) reaffirm the therapeutic promise of CD40-CD40L blockade in islet transplantation and T1D prevention. Thus, CD40L-targeting SMIs could ultimately lead to alternative immunomodulatory therapeutics for transplant recipients and prevention of autoimmune diseases that are safer, less immunogenic, more controllable (shorter half-lives), and more patient-friendly (i.e., suitable for oral administration, which makes them easier to administer) than corresponding antibody-based interventions.

Abstract 4137243: Dynamic changes of pericoronary fat attenuation index predicting changes of coronary plaque burden

Background: Percent atheroma volume (PAV) is a validated index of coronary plaque burden, linking to adverse cardiac events. Meanwhile, pericoronary fat attenuation index (FAI) on coronary computed tomography angiography (CCTA) image is a novel prognostic marker of coronary inflammation. Research Questions: It is unknown the impact of coronary inflammation (i.e., FAI) on the progression of coronary PAV in patients at an increased risk of adverse cardiac events. Methods: Patients with type 2 diabetes mellitus (T2DM) who underwent at least two clinically indicated CCTA examinations (time interval &gt; 1 year) at our center were potentially eligible for enrollment. Eligible patients presented with more than one study plaque, defined as non-obstructive stenosis at baseline and not being intervened during serial CCTA. Longitudinal CCTA images were assessed for FAI and compositional plaque characteristics (e.g., PAV) using dedicated post-processing softwares. The relationships between changes in FAI and progression of compositional PAV were examined using the logistic and linear regression analysis. Results: A total of 204 T2DM patients (mean age, 61.2 ± 9.3 years; male, 68.1%) with 366 study plaques were enrolled. All patients were treated with statins, and their time interval between longitudinal CCTAs was 14.1 (12.9, 17.6) months. Compared with patients with improved coronary inflammation (ΔFAI ≤ 0), those with deteriorated coronary inflammation (ΔFAI &gt; 0) had lower high density lipoprotein cholesterol and baseline FAI, whereas higher blood pressure (all p &lt; 0.05). Meanwhile, compared to patients with ΔFAI ≤ 0, those with ΔFAI &gt; 0 had more Δoverall and Δnon-calcified PAV (all p &lt; 0.05). Importantly, these findings were consistent in a dedicated propensity score matching analysis. In logistic regression analysis, ΔFAI &gt; 0 was associated with annual progression of overall PAV and non-calcified PAV, whereas ΔFAI ≤ 0 associated with annual regression of overall PAV and non-calcified PAV after adjusting for cardiac risk factors, baseline PAV and medications (all p &lt; 0.05). Similarly, in linear regression analysis, changes of FAI were independently positively associated with annual changes of overall PAV (β=0.545, p&lt; 0.001) and non-calcified PAV (β=0.461, p&lt; 0.001) (Figure 1). Conclusion: In this longitudinal CCTA study, changes of coronary inflammation are closely correlated with changes of overall and non-calcified PAV among T2DM patients treated with statins.

Repeatability of diffusion kurtosis tensor parameters in muscles of the lower legs.

The aim of this study was to provide measurements from and investigate the repeatability of diffusion kurtosis tensor parameters in the muscles of the lower legs. Test-retest acquisition of a kurtosis tensor sequence was performed in 13 healthy volunteers. Quantitative kurtosis tensor parameters were derived, and repeatability of each parameter was evaluated by muscle group and over the whole muscle through intraclass correlation coefficient (ICC) and within-subject coefficient of variation (wsCV). Bland-Altman analysis was also conducted. Differences in parameter values by muscle group were investigated through an analysis of variance. Axial kurtosis and radial kurtosis values from the test data were 0.63 ± 0.04 and 0.70 ± 0.05, respectively. Kurtosis tensor parameters from all muscle groups and over the whole muscle had wsCV below 15%. ICC for the parameters from most muscle groups was above 85%, with the lowest ICC over the whole muscle being 88.39%. The medial gastrocnemius and extensor digitorum longus showed highest repeatability. Mean, axial, and radial diffusivity had higher wsCV despite being lower-order terms than kurtosis. This study sought to examine the repeatability of diffusion kurtosis tensor-derived parameters in the legs and verify that they could potentially be used as longitudinal imaging metrics. wsCV values from test-retest data indicated high repeatability throughout all examined muscle groups. There were minimal differences in kurtosis and diffusivity parameters between muscle groups in this healthy volunteer cohort.