Dynamic Magnetic Resonance Imaging Research Articles

Abstract 4137891: Treated HIV infection is not associated with carotid vascular inflammation or plaque progression as assessed by dynamic contrast magnetic resonance imaging

Background: Inflammation and immune dysregulation are thought to drive residual cardiovascular disease risk among persons living with HIV (PLWH) despite effective viral suppression with antiretroviral therapy (ART). Question: We investigated differences in carotid vascular inflammation and atherosclerosis in a longitudinal cohort of virally suppressed PLWH (n = 50; on stable ART with CD4 >250 cells/mm 3 , viral load <200 copies/mL for >6 months) and HIV-uninfected controls (n = 51) matched for age, sex, hypertension, diabetes, smoking, hyperlipidemia, and family history of premature coronary artery disease. Methods&Results: Participants were > 40 years old at enrollment, 8% female, and had a high prevalence of cardiovascular risk factors ( Table 1 ). Measures of carotid inflammation and capillary permeability ( K trans ), neovascularization ( V p ), and wall thickness were assessed at baseline, 1 year, and change over 1 year by dynamic contrast-enhanced magnetic resonance imaging. Both PLWH and controls demonstrated a reduction in systolic and diastolic blood pressures and total cholesterol over 1 year; however, the difference was not significant by HIV status. PLWH had a significant reduction in triglycerides compared with controls (-48.8 mg/dL vs 12.8 mg/dL; p = 0.026). HIV was not associated with baseline, follow-up, or change in markers of systemic inflammation assessed by plasma cytokines (C-reactive protein, interleukin-6, interleukin-1ß), nor vascular inflammation or plaque as assessed by K trans , V p , carotid wall thickness, or percent wall volume ( Tables 2 & 3 ). Conclusions: In contrast to other studies of chronically treated and virally suppressed PLWH, HIV infection was not associated with carotid inflammation or plaque.

NIMG-36. PERFUSION, DIFFUSION, AND ANATOMICAL MRI BIOMARKERS FOR ASSESSING HISTOLOGICALLY-CONFIRMED MALIGNANT TRANSFORMATION IN MOLECULAR SUBTYPES OF IDH-MUTANT GLIOMAS

Abstract BACKGROUND Isocitrate dehydrogenase-mutant (IDHm) gliomas often initially present as low-grade (grade 2) gliomas but are expected to later progress into more aggressive higher-grade (grade 3-4) gliomas through malignant transformation (MT). MT is often determined non-invasively by emergence of contrast-enhancement on post-contrast T1-weighted magnetic resonance imaging (MRI), but contrast-enhancement is an imperfect surrogate for histologically-confirmed MT. This study explored perfusion, diffusion, and anatomical MRI biomarkers besides contrast-enhancement to study histologically-confirmed MT in IDHm 1p/19q-intact astrocytomas (IDHm-A) and IDHm 1p/19q-co-deleted oligodendrogliomas (IDHm-O). METHODS N=64 patients with initial histopathological grade 2 IDH-mutant glioma diagnosis who underwent repeated tissue sampling and were classified as histologically-confirmed MT (n=35) or non-MT (n=29) were retrospectively studied. Pre-surgical anatomical MRI (n=64) and, if available, diffusion-weighted imaging (n=61) and dynamic susceptibility contrast perfusion MRI (n=53) were analyzed. Tumor volumes of interest were segmented on the whole T2/FLAIR-hyperintense tumor. Measurable contrast enhancement (>1000mm3), tumor volume, sphericity, median apparent diffusion coefficient (ADC), and normalized relative cerebral blood volume (nrCBV) were compared between MT vs. non-MT IDHm-A and IDHm-O. RESULTS 81% of contrast-enhancing IDHm-A and 100% of contrast-enhancing IDHm-O underwent MT, while 41% of MT IDHm-A and 62% of MT IDHm-O were non-enhancing. Tumor volumes were significantly larger in the MT vs. non-MT groups for both IDHm-A (P=0.02) and IDHm-O (P=0.04). Whole tumor nrCBV was significantly higher (P=0.002), whole tumor ADC trended lower (P=0.06), and non-enhancing tumor sphericity was significantly lower (P=0.03) in MT vs. non-MT IDHm-A. There were no significant differences in ADC, nrCBV, nor sphericity when comparing MT vs. non-MT IDHm-O (P>0.05). CONCLUSIONS Many MT IDHm-gliomas remain non-enhancing. Tumor volumes can determine MT for both IDHm-A and IDHm-O. Diffusion and perfusion MRI show differences for MT in IDHm-A but not IDHm-O, which may reflect the different tumor biology of these IDHm molecular subtypes and their need for separate imaging biomarkers.

NIMG-23. A NOVEL APPROACH TO PERFUSION MRI STUDIES IN BRAIN TUMOR PATIENTS USING ENDOGENOUS DEOXYHEMOGLOBIN AS A CONTRAST AGENT: A PROOF-OF-CONCEPT STUDY

Abstract BACKGROUND Assessment of resting perfusion in brain tumors is clinically relevant and relies on dynamic susceptibility contrast magnetic resonance imaging using gadolinium contrast. Preliminary studies have introduced the use of controlled hemoglobin desaturation by means of a transient hypoxic stimulus during echo-planar imaging(EPI) as a surrogate for gadolinium for resting perfusion assessment in healthy subjects. In this proof of concept study, we investigated whether this approach is feasible in brain tumors and warrant further validation. METHODS A computer controlled gas blender was used to induce transient and standardized hypoxic stimulus in isocapnic conditions during EPI acquisition in a heterogenous cohort of tumor patients. The induced blood-oxygen-level-dependent(BOLD) signal changes determined by transit of a bolus of deoxygenated blood in the brain vasculature were used as a surrogate of gadolinium to calculate cerebral blood volume(CBV), cerebral blood flow(CBF) and mean transit time(MTT) using a global arterial input functions obtained through the BOLD signal measured over the middle cerebral artery as previously described by Poublanc et al. Perfusion parameters were calculated in the whole-brain voxel-by-voxel and in automatically segmented region of interest(ROI) using SPM, AFNI, Verbena softwares and MATLAB in-house written scripts. RESULTS Nine patients were included. MTT, rCBV, rCBF were calculated voxel-per-voxel. Obtained maps were overlayed on the co-registered T1 MRI scans and compared to T1CE and FLAIR to identify perfusion patterns in tumor ROIs (contrast enhancement, edema, necrosis). The deoxy-hemoglobin BOLD MRI perfusion were compared to clinical DSC-MRI when available and showed high qualitative agreement. CONCLUSION Transient and precise hemoglobin desaturation by controlled hypoxic gas modulation is safe and repeatable in brain tumor patients. The induced BOLD signal change allows measurement of resting perfusion, which qualitatively closely mimic gadolinium perfusion in different brain tumors. Deoxyhemoglobin-based perfusion warrant further quantitative validation against gadolinium in a larger cohort of heterogenous tumor patients.

Image quality in three-dimensional (3D) contrast-enhanced dynamic magnetic resonance imaging of the abdomen using deep learning denoising technique: intraindividual comparison between T1-weighted sequences with compressed sensing and with a modified Fast 3D mode wheel.

To assess the image quality of a modified Fast three-dimensional (Fast 3D) mode wheel with sequential data filling (mFast 3D wheel) combined with a deep learning denoising technique (Advanced Intelligent Clear-IQ Engine [AiCE]) in contrast-enhanced (CE) 3D dynamic magnetic resonance (MR) imaging of the abdomen during a single breath hold (BH) by intra-individual comparison with compressed sensing (CS) with AiCE. Forty-two patients who underwent multiphasic CE dynamic MRI obtained with both mFast 3D wheel using AiCE and CS using AiCE in the same patient were retrospectively included. The conspicuity, artifacts, image quality, signal intensity ratio (SIR), signal-to-noise ratio (SNR), contrast ratio (CR), and contrast enhancement ratio (CER) of the organs were compared between these 2 sequences. Conspicuity, artifacts, and overall image quality were significantly better in the mFast 3D wheel using AiCE than in the CS with AiCE (all p < 0.001). The SNR of the liver in CS with AiCE was significantly better than that in the mFast 3D wheel using AiCE (p < 0.01). There were no significant differences in the SIR, CR, and CER between the two sequences. A mFast 3D wheel using AiCE as a deep learning denoising technique improved the conspicuity of abdominal organs and intrahepatic structures and the overall image quality with sufficient contrast enhancement effects, making it feasible for BH 3D CE dynamic MR imaging of the abdomen.

Dynamic glucose-enhanced MRI of gliomas: A preliminary clinical application.

The study aimed to investigate the feasibility of dynamic glucose-enhanced (DGE) MRI technology in the clinical application of glioma. Twenty patients with glioma were examined using a preoperative DGE-MRI protocol before clinical intervention. A brief hyperglycemic state was achieved by injecting 50 mL of 50% w/w D-glucose intravenously during the DGE imaging. The total acquisition time for the DGE was 15 min. Area-under-the-curve (AUC) images were calculated using the DGE images. AUC2-7min values of the glioma core, margin area, edema area, and contralateral brain parenchyma were compared using Mann-Whitney U tests. Overall, gray and white matter areas in the AUC images showed relatively low DGE signal change and bilateral symmetry. However, the tumor cores displayed a significant hyperintensity. A high DGE signal change was also seen in the necrotic, cystic, and cerebrospinal areas. These results show that DGE MRI is a feasible technique for the study of brain tumors as part of a clinical exam. Importantly, DGE MRI showed enhancement in areas confirmed histopathologically as tumors, whereas Gd T1w MRI did not show any enhancement in this area. Since the D-glucose molecule is smaller than Gd-based contrast agents, DGE MRI may be more sensitive to subtle blood-brain barrier disruptions, thus potentially providing early information about possible malignancy. These findings provide a new perspective for the further exploration and analysis of D-glucose uptake in brain tumors.

A resident’s sharp learning curve: Post-needle stick injury arteriovenous fistula of the finger

Iatrogenic vascular injuries can be encountered during diagnostic or therapeutic interventions. Traumatic arteriovenous fistulas (AVFs) occur due to penetrating injury involving contiguous arteries and veins. We report a case of a 27-year-old postgraduate trainee who presented with swelling over her left middle finger for 5 months following a needle prick injury at the same site 1 year back, which was diagnosed with ultrasound and dynamic magnetic resonance imaging angiography. Endovascular embolization is avoided in AVFs of the hand due to the risk of distal ischemia, and surgical excision with reconstruction is the preferred treatment.

Reduction of ringing artifacts induced by diaphragm drifting in free-breathing dynamic pulmonary MRI using 3D koosh-ball acquisition.

To reduce the ringing artifacts of the motion-resolved images in free-breathing dynamic pulmonary MRI. A golden-step based interleaving (GSI) technique was proposed to reduce ringing artifacts induced by diaphragm drifting. The pulmonary MRI data were acquired using a superior-inferior navigated 3D radial UTE sequence in an interleaved manner during free breathing. Successive interleaves were acquired in an incoherent fashion along the polar direction. Four-dimensional images were reconstructed from the motion-resolved k-space data obtained by retrospectively binning. The reconstruction algorithms included standard nonuniform fast Fourier transform (NUFFT), Voronoi-density-compensated NUFFT, extra-dimensional UTE, and motion-state weighted motion-compensation reconstruction. The proposed interleaving technique was compared with a conventional sequential interleaving (SeqI) technique on a phantom and eight subjects. The quantified ringing artifacts level in the motion-resolved image is positively correlated with the quantified nonuniformity level of the corresponding k-space. The nonuniformity levels of the end-expiratory and end-inspiratory k-space binned from GSI data (0.34 ± 0.07, 0.33 ± 0.05) are significantly lower with statistical significance (p < 0.05) than that binned from SeqI data (0.44 ± 0.11, 0.42 ± 0.12). Ringing artifacts are substantially reduced in the dynamic images of eight subjects acquired using the proposed technique in comparison with that acquired using the conventional SeqI technique. Ringing artifacts in the motion-resolved images induced by diaphragm drifting can be reduced using the proposed GSI technique for free-breathing dynamic pulmonary MRI. This technique has the potential to reduce ringing artifacts in free-breathing liver and kidney MRI based on full-echo interleaved 3D radial acquisition.

The Effectiveness of Whole Body Magnetic Resonance Imaging Used in Health Screening Programs in Early Stage Cancer Diagnosis

Objective: We aim to present the findings and effectiveness of Whole Body Magnetic Resonance Imaging (WBMRI), which we use in the Health Screening Program (HSP) to diagnose cancer in early stage. Methods: This retrospective study was conducted between January 2017-February 2023. 393 individuals, between the ages of 18 and 85, who underwent WBMRI for HSP purposes, were included. The mean age was 50. Results: Malignancy suspicious lesions were observed in the head/neck region in 25 cases. Additional Magnetic Resonance (MRI) and Ultrasound (US) were performed. Mediastinal pathology was observed in 23 cases, and non-mediastinal thoracic pathologies were detected in 15. Therefore thorax Computed Tomography (CT), mammography, and breast US were performed. Benign lesions were observed in the liver in 44 cases, and US was performed. Malignancy-suspicious lesions in the liver were observed in 4, and dynamic abdominal MRI was performed. Cholelithiasis was observed in 16, and confirmed by US. The most common renal findings were; cysts and pelvicalyceal ectasia. Adrenal adenoma was observed in 5 cases. Two of the females had suspicion of gynecological malignancy. Massive diffuse concentric wall thickening was observed in the sigmoid colon, and colonoscopy was performed on one male. Musculoskeletal benign lesions were detected in 99 cases, and malignancy-suspicious lesions were detected in 35. Additional examinations such as US, CT, MRI, PET-CT, scintigraphy, and colonoscopy were performed on 172 cases. Malignancy was detected in 11 cases (2.8%). Conclusion: WBMRI is a radiation-free, non-invasive, short-term examination method. WBMRI is beneficial in diagnosing early-stage cancer.

Utility of cervical dynamic magnetic resonance imaging for evaluating patients with cervical myelopathy: a retrospective study.

Retrospective observational study. This study aimed to evaluate the utility of cervical dynamic magnetic resonance imaging (dMRI) in the assessment of cervical canal stenosis. Cervical spondylotic myelopathy has been intricately linked to both static and dynamic narrowing of the cervical spinal canal. Traditional MRI with the neck in a neutral position fails to identify the dynamic changes and may lead to misdiagnosis. Cervical dMRI is a promising tool for evaluating cervical myelopathy, enabling clinicians to assess spinal cord compression, segmental instability, and alterations in range of motion, often missed on conventional imaging. A retrospective analysis was conducted on 369 patients with symptoms of cervical myelopathy assessed using cervical dMRI. After assessing the subaxial cervical spine at each disc level (C3-T1), significant changes in the degree of central canal stenosis were determined. The appearance and extent of hyperintense lesions on T2-weighted sequences were also noted. Overall, 653/1,845 (35.39%) disc levels showed an increase in stenosis grade on extension MRI, with 168/653 (25.72%) and 180/653 (27.56%) disc levels changing from grades 0/1 to grades 2 and 3, respectively. Moreover, 120/369 (32.52%) patients showed a mean increase of 1.55±0.75 levels of compression on extension MRI when compared to neutral MRI. A fresh-appearing hyperintense lesion was observed in 79 (4.28%) disc levels on flexion MRI, which was not visualized on neutral MRI. Cervical dMRI may help surgeons plan for surgery, discuss the prognosis with the patient, and safeguard themselves from medico-legal issues arising from improper or missed diagnosis and treatment.

Phenotypic, Electrophysiologic, and Imaging Spectrum of Hirayama Disease from Northern India.

Cervical flexion-induced myelopathy, also known as Hirayama disease (HD), is a lower motor neuron disorder seen mainly in adolescents and young adults, affecting the C7-T1 myotomes, presenting as asymmetric weakness with wasting of one or both the distal upper limbs. We aimed to describe the clinical features, electrophysiology, and radiologic features of HD in a tertiary care institute in northern India. One hundred and forty patients between 2017 and 2022 with clinical and imaging features consistent with HD were retrospectively reviewed from the All India Institute of Medical Sciences-Comprehensive Neuromuscular Diseases center database. Majority were males with the mean age of onset of illness being 17.8 years. The median duration of the symptoms was 3 (1.5-4) years. Sixty-nine (49%) patients had unilateral involvement, and the disease was actively progressing in 88 (63%) patients at presentation. Two families had history of HD in two (1.4%) siblings. Electromyography showed abnormal findings in the clinically involved limb in all the patients and in the clinically uninvolved limb in 17/50 (34%) patients. Flexion magnetic resonance imaging (MRI) demonstrated forward dural displacement in 134 (96%) patients and asymmetric cord flattening in 124 (88.5%) patients. Disability was graded as mild, moderate, and severe; 12 (13%) had severe disability. The majority were managed conservatively, and four underwent surgery for HD. A high index of suspicion of HD needs to be kept in a young male presenting with distal upper limb weakness and atrophy. Dynamic MRI of the cervical spine in young adults presenting with hand wasting is inevitable. This disease needs to be managed aggressively and early to prevent serious dysfunction and loss of productivity.

An adaptive parameter decoupling algorithm-based image reconstruction model (ADAIR) for rapid golden-angle radial DCE-MRI

Objective. The acceleration of magnetic resonance imaging (MRI) acquisition is crucial for both clinical and research applications, particularly in dynamic MRI. Existing compressed sensing (CS) methods, despite being effective for fast imaging, face limitations such as the need for incoherent sampling and residual noise, which restrict their practical use for rapid MRI.Approach. To overcome these challenges, we propose a novel image reconstruction framework that integrates the MRI physical model with a flexible, self-adjusting, decoupling data-driven model. We validated this method through experiments using both simulated andin vivodynamic contrast-enhanced MRI datasets.Main results. The experimental results demonstrate that the proposed framework achieves high spatial and temporal resolution reconstructions. Additionally, when compared to state-of-the-art image reconstruction approaches, our method significantly enhances acceleration capabilities, enabling sparse and rapid imaging with high resolution.Significance. Our proposed framework offers a promising solution for real-time imaging and image-guided radiation therapy applications by providing superior performance in achieving high spatial and temporal resolution reconstructions, thus addressing the limitations of existing CS schemes.

MRI recovery with self-calibrated denoisers without fully-sampled data.

Acquiring fully sampled training data is challenging for many MRI applications. We present a self-supervised image reconstruction method, termed ReSiDe, capable of recovering images solely from undersampled data. ReSiDe is inspired by plug-and-play (PnP) methods, but unlike traditional PnP approaches that utilize pre-trained denoisers, ReSiDe iteratively trains the denoiser on the image or images that are being reconstructed. We introduce two variations of our method: ReSiDe-S and ReSiDe-M. ReSiDe-S is scan-specific and works with a single set of undersampled measurements, while ReSiDe-M operates on multiple sets of undersampled measurements and provides faster inference. Studies I, II, and III compare ReSiDe-S and ReSiDe-M against other self-supervised or unsupervised methods using data from T1- and T2-weighted brain MRI, MRXCAT digital perfusion phantom, and first-pass cardiac perfusion, respectively. ReSiDe-S and ReSiDe-M outperform other methods in terms of peak signal-to-noise ratio and structural similarity index measure for Studies I and II, and in terms of expert scoring for Study III. We present a self-supervised image reconstruction method and validate it in both static and dynamic MRI applications. These developments can benefit MRI applications where the availability of fully sampled training data is limited.

Role of Contrast Perfusion Weighted Magnetic Resonance Imaging in Grading of Brain Tumors with Histopathological Correlation

Background: Traditional MRI sequences provide precise anatomical information about brain tumors. But these sequences can’t quantitatively evaluate vascular physiology, or capture tumor biology at the molecular level; which is important for tumor grading, therapeutic assessment, and prognostication. Furthermore, non-enhancing parts of the tumor affected brain, which generally indicates peri-tumoral brain edema with infiltrative tumor cells, is not visible on conventional MRI sequences. Perfusion weighted Magnetic Resonance Imaging (PW-MRI) techniques such as Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE-MRI) and Dynamic Susceptibility Contrast Magnetic Resonance Imaging (DSC-MRI) have shown promise as imaging biomarkers for glioma therapy, since these new sequences can also provide information about vascular hemodynamics. Our study was first prospective study from Himalayan belt of India, wherein we tried to assess the role of PW-MRI in the grading of brain tumors, with histopathological correlation. Aim and Objective: To compare tumor perfusion and histopathological tumor grading, in evaluation of brain tumor especially gliomas. Material and Method: 40 patients who were referred to Department of Radiodiagnosis for evaluation of brain tumor, and who gave informed consent, were included in this prospective study, done over a period of 18 months. All patients underwent MRI, followed by surgical resection. Observation and Result: In our study, diagnostic accuracy was 90% for mean rCBV (lesion) (cut off: 7 by ROC), mean rCBF (lesion) (cut off: 13.9 by ROC), and rCBF ratio (cut off: 2.9 by ROC); for differentiating benign versus malignant brain tumor. rCBF ratio was found to be best diagnostic parameter with sensitivity of 96%, specificity of 80%, positive predictive value of 89%, negative predictive value of 92%, diagnostic accuracy of 90%, area under ROC curve=0.909, and p value&lt;0.001. Conclusion: We come to conclusion that high grade brain tumor display higher CBF, than do low grade brain tumor. Three parameters showed good diagnostic accuracy, which includes rCBF ratio, mean rCBF (lesion), and mean rCBV (lesion). These parameters can be used to predict the grade of the brain tumor, with good diagnostic accuracy.

Electric potential energy optimized 3D radial sampling trajectories for MRI

A novel method for creating “golden” 3D center-out radial MRI sampling trajectories was developed and analyzed. This method, called ELECTRO (ELECTRic potential energy Optimized), uses repulsive forces to minimize electric potential energy. An objective function \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:G\\left(S\\right)$$\\end{document}, the electric potential energies of all subsets of consecutive readouts in a 3D radial trajectory, and its reduced form were minimized using a multi-stage optimization strategy. A metric called normalized mean nearest neighbor angular distance (NMNA) was proposed for describing distributions of points on a sphere. ELECTRO and other relevant golden trajectories were compared in silico using NMNA and point spread function analysis. Consecutive readouts from an ELECTRO trajectory were well spread out, with consistent NMNA values across sphere sizes (σNMNA = 0.005) and between regions on the sphere (NMNA ≈ 1.49). Conversely, the supergolden trajectory had poor consistency in NMNA values (σNMNA = 0.090) and clustering (NMNA = 1.28 at the pole with 40,000 readouts) that lead to artifact in the point spread function. Multi-stage optimization was faster than single-stage and obtained lower values of \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:G\\left(S\\right)$$\\end{document} (e.g., 0.87 vs. 0.91, for a sphere size of 40). In conclusion, ELECTRO trajectories are more golden than other 3D center-out radial trajectories, making them a suitable candidate for dynamic 3D MR imaging.

Limited utility of subendometrial enhancement in assessing the interface between the endometrium and myometrium

This study was conducted to re-evaluate the utility of subendometrial enhancement (SEE) in assessing the interface between the endometrium and myometrium. In total, 110 women who underwent pelvic magnetic resonance imaging (MRI) for non-endometrial gynecologic diseases were enrolled in this prospective study. Two radiologists independently assessed the presence or absence of subendometrial enhancement (SEE) on dynamic contrast-enhanced (CE) MRI. A subgroup analysis was performed to evaluate the impact of menstrual status on the detection of SEE. Identified areas of SEE were rated using a 4-point Likert scale to determine their reliability in assessing the interface between the endometrium and myometrium. SEE was identified in 44.5% (49/110) of cases by radiologist 1 and in 39.1% (43/110) by radiologist 2. A subgroup analysis indicated no significant differences in the detection of SEE based on menstrual status. The identified areas of SEE were deemed reliable for assessing the interface between the endometrium and myometrium in 24.5% (12/49) of the cases evaluated by radiologist 1 and in 32.6% (14/43) of those evaluated by radiologist 2. Among the 110 women studied, reliable areas of SEE for assessing the interface between the endometrium and myometrium were observed in 10.9% (n = 12) by radiologist 1 and 12.7% (n = 14) by radiologist 2. The evaluation of SEE using dynamic CE MRI may be limited in its ability to assess the interface between the endometrium and myometrium.

Beyond the Surface: Investigating Clinical and Magnetic Resonance Imaging Dynamics in Knee Injuries: A Cross-sectional Study

Abstract Context: Orthopedic surgeons frequently encounter knee soft tissue injuries such as meniscal and ligament injuries. This study seeks to explore the diagnostic efficacy of clinical examination, magnetic resonance imaging (MRI), and arthroscopy in identifying knee injuries. Subjects and Methods: This prospective observational study enrolled 120 patients with knee injuries slated for arthroscopic surgery based on clinical and MRI assessments. The study assessed and compared the diagnostic accuracy of clinical and MRI findings. Statistical Analysis Used: Statistical analysis was performed using SPSS software (SPSS Inc., Chicago, IL, USA) for the Windows program (21.0 version). The Spearman correlation analysis was done to assess the relationship between the various parameters. The level of agreement was assessed using Cohen’s kappa statistics. Interpretation of kappa statistics is as follows: 0 to 0.20-Slight agreement; 0.1 to 0.39-Fair; 0.40 to 0.59-Moderate; 0.60 to 0.79- Substantial and 0.80 to 0.90-Almost perfect agreement. Sensitivity, specificity, accuracy, positive predictive value and negative predictive value were calculated and observed by using 2 × 2 contingency table. P &lt; 0.05 was considered statistically significant. Results: When comparing MRI and arthroscopy findings, the anterior cruciate ligament (ACL) tear exhibited the highest sensitivity and specificity at 100.00% and 91.84%, respectively, while the medial meniscus tear had the lowest sensitivity and specificity at 80.23% and 61.76%. Regarding the comparison between clinical examination and arthroscopy, the Lachman test displayed the highest sensitivity at 95.92%, whereas McMurray’s test (Lateral Meniscus) had the lowest sensitivity at 54.55%, and the posterior Drawer’s test showed the lowest specificity at 60.00%. Lachman also demonstrated the highest diagnostic accuracy at 98.33%, while the posterior Drawer’s test had the lowest diagnostic accuracy at 70.00%. Conclusions: Despite a few limitations, clinical examination and MRI currently stand out as the most precise non-invasive methods for detecting abnormalities in the menisci and the ACL. These diagnostic approaches provide valuable insights into the structural integrity of these knee components, allowing for a comprehensive assessment without the need for invasive procedures.

Observation of dynamic position and morphological changes of temporomandibular joint discs under Angle's classification

Objective: To observe the dynamic changes of the temporomandibular joint (TMJ) disc in joint movement under different Angle's classification, providing reference for understanding joint functional movement and providing a basis for more accurate clinical imaging diagnosis. Methods: A total of 30 patients (13 males and 17 females) with temporomandibular disorders who were admitted to Beijing Friendship Hospital, Capital Medical University and General Hospital of the People's Liberation Army from January 2022 to April 2024 were enrolled. Thirty adults (13 males and 17 females) with different Angle's classification, with an average age of (34.4±8.5) years, were subjected to dynamic imaging of their TMJ from the closed position to the maximum opening position, and then to the closed position using MRI. The position and morphological changes of the articular discs were observed. Results: The results showed that volunteers with no displacement of the articular disc in class Ⅰ, Ⅱ, and Ⅲ relationships had different shapes of the articular disc during open and closed mouth movements. However, in the maximum opening position, the articular disc were all located directly below the maxillary nodules, and their shape is double concave. In terms of irreversible anterior displacement of the articular disc, in class Ⅰ Angle, the posterior zone of the disc contacts the anterior inclined plane of condyle from the maximum opening position back to the front of the closing position. In class Ⅱ, the posterior zone of the disc contacts the anterior inclined plane of condyle from the beginning of opening position to maximum opening position. In class Ⅲ, the posterior zone of the disc is always in contact with the anterior inclined plane of condyle throughout the entire movement process. And among them, the articular disc presents a forward displacement state at the closing position, its morphology undergoes folding phenomenon. When the openness is 2.5 cm, the articular disc moves up to a certain extent, and is closer to the anterior inclined plane of condyle, and its shape is also partially changed. When the openness is 4.3 cm, the shape of the articular disc, located between the anterior inclined plane of the joint node and the posterior inclined plane of the condyle, is typical double concave, which is sufficient to show that the articular disc is reversible when maximum opening position is reached. In terms of reversible anterior disc displacement, in class Ⅰ Angle, the posterior zone of the disc contact with the anterior inclined plane of condyle at the beginning of the opening position and the end of the closing position. In classⅡ Angle, the posterior zone of the articular disc is not in contact with the anterior inclined plane of condyle. In class Ⅲ Angle, the posterior zone of the articular disc contact with the anterior inclined plane of condyle at the end of the closing position. Conclusions: Multi level dynamic MR imaging data of the temporomandibular joint can dynamically observe the movement of the temporomandibular joint, intuitively and accurately display the position and shape of the articular disc during movement, and can serve as a useful supplement to static conventional MR imaging of the TMJ. The patient's TMJ needs to reach the maximum opening position in order to determine whether the joint disc displacement can be reversible or not.

Quantitative spatial visualization of X-ray irradiation via redox reaction by dynamic nuclear polarization magnetic resonance imaging

The dose of X-ray irradiation is commonly measured by point assessment with an ionization chamber dosimeter. However, to achieve spatially accurate delivery of X-ray to avoid the exposure to normal tissues, an accurate imaging method for spatially and quantitatively detecting exposure is required. Herein, we present a novel method to visualize X-ray exposure using low-field dynamic nuclear polarization magnetic resonance imaging (DNP-MRI) with nitroxyl radical tempol as the chemical dosimeter. In this system, gel phantoms containing glutathione (GSH) and the paramagnetic tempol radical were used to monitor the deposited X-ray-irradiation via the redox reaction. The tempol radical level was evaluated by DNP-MRI whose signal intensity was linearly correlated with the radical concentration. The radical level in the presence of GSH decreased in proportion to the dose of X-irradiation deposited. In an imaging experiment simulating clinical radiotherapy, we used a clinical linear accelerator with a radiotherapy planning software to confirm the utility of the exposure imaging. The X-ray exposure and its distribution were clearly visualized on the gel phantom image acquired by DNP-MRI. The results were consistent with those specified in the radiotherapy plan where the intensity of the radiation beam was modulated. This exposure estimation will be useful for determining an accurate irradiation field and reducing off-target exposure in clinical settings.

Quantifying Normal Diaphragmatic Motion and Shape and their Developmental Changes via Dynamic MRI

BackgroundThe diaphragm is a critical structure in respiratory function, yet in-vivo quantitative description of its motion available in the literature is limited. Research QuestionHow to quantitatively describe regional hemi-diaphragmatic motion and curvature via free-breathing dynamic magnetic resonance imaging (dMRI)? Study Design and MethodsIn this prospective cohort study we gathered dMRI images of 177 normal children and young adults and segmented hemi-diaphragm domes in end-inspiration and end-expiration phases of the constructed 4D image. We selected 25 points uniformly located on each 3D hemi-diaphragm surface. Based on the motion and local shape of hemi-diaphragm at these points, we computed the velocities and sagittal and coronal curvatures in 13 regions on each hemi-diaphragm surface and analyzed the change in these properties with age and sex. ResultsOur cohort consisted of 94 Females, 6-20 years (12.09+3.73), and 83 Males, 6-20 years (11.88+3.57). We observed velocity range: ∼2mm/s to ∼13mm/s; Curvature range – Sagittal: ∼3m-1 to ∼27m-1; Coronal: ∼6m-1 to ∼20m-1. There was no significant difference in velocity between sexes, although the pattern of change in velocity with age was different for the two groups. Strong correlations in velocity were observed between homologous regions of right and left hemi-diaphragms. There was no significant difference in curvatures between sexes or change in curvatures with age. InterpretationRegional motion/curvature of the 3D diaphragmatic surface can be estimated using free-breathing dynamic MRI. Our analysis sheds light on here-to-fore unknown matters such as how the pediatric 3D hemi-diaphragm motion/shape varies regionally, between right and left hemi-diaphragms, between sexes, and with age.

VSHARP: Variable Splitting Half-quadratic ADMM algorithm for reconstruction of inverse-problems

Medical Imaging (MI) tasks, such as accelerated parallel Magnetic Resonance Imaging (MRI), often involve reconstructing an image from noisy or incomplete measurements. This amounts to solving ill-posed inverse problems, where a satisfactory closed-form analytical solution is not available. Traditional methods such as Compressed Sensing (CS) in MRI reconstruction can be time-consuming or prone to obtaining low-fidelity images. Recently, a plethora of Deep Learning (DL) approaches have demonstrated superior performance in inverse-problem solving, surpassing conventional methods. In this study, we propose vSHARP (variable Splitting Half-quadratic ADMM algorithm for Reconstruction of inverse Problems), a novel DL-based method for solving ill-posed inverse problems arising in MI. vSHARP utilizes the Half-Quadratic Variable Splitting method and employs the Alternating Direction Method of Multipliers (ADMM) to unroll the optimization process. For data consistency, vSHARP unrolls a differentiable gradient descent process in the image domain, while a DL-based denoiser, such as a U-Net architecture, is applied to enhance image quality. vSHARP also employs a dilated-convolution DL-based model to predict the Lagrange multipliers for the ADMM initialization. We evaluate vSHARP on tasks of accelerated parallel MRI Reconstruction using two distinct datasets and on accelerated parallel dynamic MRI Reconstruction using another dataset. Our comparative analysis with state-of-the-art methods demonstrates the superior performance of vSHARP in these applications.