Dynamic Magnetic Resonance Imaging Research Articles

Inferior Frontal Sulcal Hyperintensity on Fluid-Attenuated Inversion Recovery Is Related to Cerebrospinal Fluid Clearance via Putative Meningeal Lymphatics.

Inferior frontal sulcal hyperintensity (IFSH) on FLAIR sequence may indicate elevated cerebrospinal fluid (CSF) wastes. The objective of this study was to investigate its association with the clearance function of putative meningeal lymphatic vessels (mLVs). We included patients who underwent FLAIR sequence and dynamic contrast MRI with intrathecal administration of contrast agent. The visibility of IFSH was quantitatively assessed by measuring the mean signal intensity of inferior frontal sulci on 2D FLAIR. The clearance function of putative mLVs was defined as the percentage change of signal unite ratio in the parasagittal dura from baseline to 4.5, 15 and 39 hours after intrathecal injection on dynamic contrast MRI. Additionally, imaging markers of cerebral small vessel disease, including white matter hyperintensities and enlarged perivascular spaces, were measured. Correlation analysis and linear regression were employed to verify the association of IFSH with the clearance function of mLVs. A total of 76 patients were included in the study. The visibility of IFSH was found to be associated with the percentage change of signal unite ratio in parasagittal dura from baseline to 15 and 39 hours in adjusted analyses. Furthermore, the visibility of IFSH was positively related to the age, scores of both periventricular and deep white matter hyperintensities, and the grade of enlarged perivascular spaces in centrum semiovale. These findings suggest that the visibility of IFSH on 2D FLAIR may serve as an indicator of clearance dysfunction of mLVs and may be implicated in the development of cerebral small vessel disease.

Image Quality Assessment Tool for Conventional and Dynamic Magnetic Resonance Imaging Acquisitions

Image quality assessment of magnetic resonance imaging (MRI) data is an important factor not only for conventional diagnosis and protocol optimization but also for fairness, trustworthiness, and robustness of artificial intelligence (AI) applications, especially on large heterogeneous datasets. Information on image quality in multi-centric studies is important to complement the contribution profile from each data node along with quantity information, especially when large variability is expected, and certain acceptance criteria apply. The main goal of this work was to present a tool enabling users to assess image quality based on both subjective criteria as well as objective image quality metrics used to support the decision on image quality based on evidence. The evaluation can be performed on both conventional and dynamic MRI acquisition protocols, while the latter is also checked longitudinally across dynamic series. The assessment provides an overall image quality score and information on the types of artifacts and degrading factors as well as a number of objective metrics for automated evaluation across series (BRISQUE score, Total Variation, PSNR, SSIM, FSIM, MS-SSIM). Moreover, the user can define specific regions of interest (ROIs) to calculate the regional signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR), thus individualizing the quality output to specific use cases, such as tissue-specific contrast or regional noise quantification.

Pseudo-resting-state functional MRI derived from dynamic susceptibility contrast perfusion MRI can predict cognitive impairment in glioma.

Resting-state functional MRI (rs-fMRI) can be used to estimate functional connectivity (FC) between different brain regions, which may be of value for identifying cognitive impairment in patients with brain tumors. Unfortunately, neither rs-fMRI nor neurocognitive assessments are routinely assessed clinically, mostly due to limitations in exam time and cost. Since DSC perfusion MRI is often used clinically to assess tumor vascularity and similarly uses a gradient echo-EPI sequence for T2*sensitivity, we theorized a "pseudo-rs-fMRI" signal could be derived from DSC perfusion to simultaneously quantify FC and perfusion metrics, and these metrics can be used to estimate cognitive impairment in patients with brain tumors. N=24 consecutive patients with gliomas were enrolled in a prospective study that included DSC perfusion MRI, rs-fMRI, and neurocognitive assessment. Voxel-wise modeling of contrast bolus dynamics during DSC acquisition was performed and then subtracted from the original signal to generate a residual "pseudo-rs-fMRI" signal. Following the pre-processing of pseudo-rs-fMRI, full rs-fMRI, and a truncated version of the full rs-fMRI (first 100 timepoints) data, the default mode, motor, and language network maps were generated with atlas-based ROIs. Dice scores were calculated for the resting-state network maps from pseudo-rs-fMRI and truncated rs-fMRI using the full rs-fMRI maps as reference. Seed-to-voxel and ROI-to-ROI analyses were performed to assess FC differences between cognitively impaired and non-impaired patients. Dice scores for the group-level and patient-level (mean±SD) default mode, motor, and language network maps using pseudo-rs-fMRI were 0.905/0.689±0.118 (group/patient), 0.973/0.730±0.124, and 0.935/0.665±0.142, respectively. There was no significant difference in Dice scores between pseudo-rs-fMRI and the truncated rs-fMRI default mode (P=0.97) or language networks (P=0.30), but there was a difference in motor networks (P=0.02). A multiple logistic regression classifier applied to ROI-to-ROI FC networks using pseudo-rs-fMRI could identify cognitively impaired patients (Sensitivity=84.6%, Specificity=63.6%, ROC AUC=0.7762±0.0954 (SE), P=0.0221) and performance was not significantly different than full rs-fMRI predictions (AUC=0.8881±0.0733 (SE), P=0.0013, P=0.29 compared to pseudo-rs-fMRI). DSC perfusion MRI-derived pseudo-rs-fMRI data can be used to perform typical rs-fMRI FC analyses that may identify cognitive decline in patients with brain tumors while still simultaneously performing perfusion analyses.ABBREVIATIONS: AUC = Area under curve; BOLD = Blood oxygenation level dependent; FC = Functional connectivity; MNI = Montreal Neurological Institute; ROC = Receiver operating characteristic; Rs-fMRI = Resting-state functional MRI.

Abstract PO3-15-04: Oncotype DX Recurrence Score as an Informative Tool to Optimize Neoadjuvant Therapy in HR-positive, HER2-negative Breast Cancers

Abstract Oncotype DX Recurrence Score as an Informative Tool to Optimize Neoadjuvant Therapy in HR-positive, HER2-negative Breast Cancers Background: Neoadjuvant therapy (NAT) in HR+/HER2- breast cancers rarely leads to pathological complete response (pCR) and often doesn’t achieve substantial tumor shrinkage. Therefore, neoadjuvant therapy in HR+/HER2- breast cancers has the most value in the assessment of in vivo treatment response. For this purpose, biomarkers that can predict clinical and pathological response to systemic therapy could help inform treatment. The role of Oncotype DX testing in the management of early-stage HR+/HER2- breast cancer has been widely recognized in the adjuvant setting. However, no large prospective studies evaluating the Oncotype DX test in the neoadjuvant setting have clearly shown its predictive or prognostic utility to date. In this study, we evaluated the effect of the recurrence score (RS) on systemic treatment recommendations and its correlation to NAT response. Methods: Patients with clinically selected T2-T4 and/or clinically node positive HR+/HER2- breast cancer who were referred to BC Cancer Vancouver for consideration of NAT between September 2021 – April 2023 were screened for study eligibility. Suitable candidates who agreed to participate in the study had Oncotype DX testing on core biopsy specimens and Ki-67 testing on the core biopsy and final resection specimen. Clinico-pathological information, treatment regimens, operative details, and clinical, radiologic, and pathological responses were recorded. Results: Of the 66 patients who met eligibility criteria, 40 enrolled in the study comprising the accrual rate of 60.6 %. There were multiple factors that influenced patients and/or Oncologists participation in the study highlighting the low uptake of NAT in HR+/HER2- tumors. Technical feasibility of obtaining Oncotype DX from core biopsy samples was 95% which correlates with our previously reported data on a smaller cohort. The mean turnaround time from patient consent to RS report was 18.5 calendar days. The mean time from the initial consult to the start of NAT was 18.8 calendar days. Amongst all tumors tested, 28 % had RS equal or greater than 26 while only 2 % of participants had a score less than 10. Overall, 32 % of treatment recommendations were changed based on RS. Approximately 31% of patients who were initially recommended to receive neoadjuvant chemotherapy were spared from this treatment based on low RS. Conversely, 23.8% of patients who were recommended to pursue upfront surgery were escalated to chemotherapy due to a high RS. Approximately 88 % of the participants who were treated with neoadjuvant chemotherapy had a favourable clinical response and 38.5% had a complete clinical response. There were no pCR observed amongst patients who completed surgery after neoadjuvant chemotherapy, but half of them were rendered eligible for less surgery (either spared a mastectomy and/or an axillary dissection). Conclusions: Oncotype DX testing changed systemic treatment recommendations in one third of neoadjuvant patients and presents a unique opportunity for personalized medicine. Pre-operative testing thus influenced clinical decision-making, allowing treatment de-escalation and omission of chemotherapy in those with a low RS and conversely an earlier escalation of systemic therapy for those with a high RS. Turnaround time of the Oncotype DX assay on a core biopsy sample was acceptable and did not significantly delay treatment initiation. The benefit of the Oncotype DX assay prior to NAT was valuable for predicting in vivo response although pCR was not observed in any of the patients enrolled. Analyses are ongoing to further correlate RS to neoadjuvant response and to dynamic Ki-67 and MRI changes. Citation Format: Lidiya Luzhna, Stephen Chia, Mehrnoosh Pauls, Nathalie Levasseur. Oncotype DX Recurrence Score as an Informative Tool to Optimize Neoadjuvant Therapy in HR-positive, HER2-negative Breast Cancers [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-15-04.

Predictability of the radiological response to Yttrium-90 transarterial radioembolization by dynamic magnetic resonance imaging-based radiomics analysis in patients with intrahepatic cholangiocarcinoma

The study aims to investigate the predictability of the radiological response in intrahepatic cholangiocarcinoma (iCC) patients undergoing Yttrium-90 transarterial radioembolization (TARE) with a combined model built on dynamic magnetic resonance imaging (MRI)-based radiomics and clinical features. Thirty-six naive iCC patients who underwent TARE were included in this study. The tumor segmentation was performed on the axial T2-weighted (T2W) without fat suppression, axial T2W with fat suppression, and axial T1-weighted (T1W) contrast-enhanced (CE) sequence in equilibrium phase (Eq). At the sixth month MRI follow-up, all patients were divided into responders and non-responders according to the modified Response Evaluation Criteria in Solid Tumors. Subsequently, a radiomics score (rad-score) and a combined model of the rad-score and clinical features for each sequence were generated and compared between the groups. Thirteen (36.1%) patients were considered responders, and the remaining 23 (63.9%) were non-responders. Responders exhibited significantly lower rad-scores than non-responders (P < 0.050 for all sequences). The radiomics models showed good discriminatory ability with an area under the curve (AUC) of 0.696 [95% confidence interval (CI), 0.522–0.870] for the axial T1W-CE-Eq, AUC of 0.839 (95% CI, 0.709–0.970) for the axial T2W with fat suppression, and AUC of 0.836 (95% CI, 0.678–0.995) for the axial T2W without fat suppression. Radiomics models created by pre-treatment MRIs can predict the radiological response to Yttrium- 90 TARE in iCC patients with high accuracy. Combining radiomics with clinical features could increase the power of the test. Large-scale studies of multi-parametric MRIs with internal and external validations are needed to determine the clinical value of radiomics in iCC patients.

Exploring shoulder joint pain: a comparative analysis of dynamic ultrasonography and magnetic resonance imaging

BACKGROUND: To evaluate shoulder joint pain, the study concentrated on evaluating the diagnostic accuracy of ultrasonography and magnetic resonance imaging. AIM: By comparing the results from both modalities within the same patient group, the study aimed to identify potential challenges in image interpretation, underscoring the limitations of ultrasonography and magnetic resonance imaging. MATERIALS AND METHODS: Patients with shoulder joint pain were included through purposive sampling. These patients underwent ultrasonography and magnetic resonance imaging, and the results were correlated. Various shoulder pathologies, including tendon tears, bursitis, degenerative changes, calcifications, and impingement, were analyzed. RESULTS: The study comprised 35 patients who underwent ultrasonography and magnetic resonance imaging detecting pathologies such as subscapularis and supraspinatus tendon injuries, partial and full-thickness tears, peribicipital tendon fluid, subcoracoid and subacromial-subdeltoid bursitis, acromioclavicular joint degeneration, tendon calcification, and impingement. Comparative analysis showed varying sensitivities, specificities, positive predictive values, negative predictive values, and accuracy for different pathologies. CONCLUSION: Compared with ultrasonography, magnetic resonance imaging demonstrated greater sensitivity and specificity in identifying conditions causing shoulder pain. Ultrasonography’s affordability, real-time capabilities, and ability to compare results with the unaffected side make it a useful first diagnostic step for shoulder pain. Ultrasonography, although a quick and cost-effective initial diagnostic tool, has limitations, including operator dependence and lower sensitivity in certain conditions. In contrast, magnetic resonance imaging is employed as a confirming measure or in instances where diagnosis is challenging. The study emphasized the complementary roles of ultrasonography and magnetic resonance imaging in the diagnosis of shoulder joint pain, with magnetic resonance imaging as the more accurate and complete imaging modality.

Dynamic Cervical Spinal Canal Stenosis: Identifying Imaging Risk Factors in Extended Positions.

A retrospective study at a single academic institution. This study aimed to identify imaging risk factors for stenosis in extended neck positions undetectable in preoperative neutral magnetic resonance imaging (MRI) and improving decompression strategies for cervical spine disorders. Cervical disorders are influenced by various dynamic factors, with spinal stenosis appearing during neck extension. Despite the diagnostic value of dynamic cervical MRI, standard practice often uses neutral-position MRI, potentially influencing surgical outcomes. This study analyzed 143 patients who underwent decompression surgery between 2012 and 2014, who had symptomatic cervical disorders and MRI evidence of spinal cord or nerve compression but had no history of cervical spine surgery. Patient demographics, disease type, Japanese Orthopedic Association score, and follow-up periods were recorded. Spinal surgeons conducted radiological evaluations to determine stenosis levels using computed tomography myelography or MRI in neutral and extended positions. Measurements such as dural tube and spinal cord diameters, cervical alignment, range of motion, and various angles and distances were also analyzed. The residual space available for the spinal cord (SAC) was also calculated. During extension, new stenosis frequently appeared caudal to the stenosis site in a neutral position, particularly at C5/C6 and C6/C7. A low SAC was identified as a significant risk factor for the development of new stenosis in both the upper and lower adjacent disc levels. Each 1-mm decrease in SAC resulted in an 8.9- and 2.7-fold increased risk of new stenosis development in the upper and lower adjacent disc levels, respectively. A practical SAC cutoff of 1.0 mm was established as the threshold for new stenosis development. The study identified SAC narrowing as the primary risk factor for new stenosis, with a clinically relevant cutoff of 1 mm. This study highlights the importance of local factors in stenosis development, advocating for further research to improve outcomes in patient with cervical spine disorders.

Stepwise algorithm using computed tomography and magnetic resonance imaging for differential diagnosis of fat-poor angiomyolipoma in small renal masses: A prospective validation study.

To validate the diagnostic accuracy of a stepwise algorithm to differentiate fat-poor angiomyolipoma (fp-AML) from renal cancer in small renal masses (SRMs). We prospectively enrolled 223 patients with solid renal masses <4 cm and no visible fat on unenhanced computed tomography (CT). Patients were assessed using an algorithm that utilized the dynamic CT and MRI findings in a stepwise manner. The diagnostic accuracy of the algorithm was evaluated in patients whose histology was confirmed through surgery or biopsy. The clinical course of the patients was further analyzed. The algorithm classified 151 (68%)/42 (19%)/30 (13%) patients into low/intermediate/high AML probability groups, respectively. Pathological diagnosis was made for 183 patients, including 10 (5.5%) with fp-AML. Of these, 135 (74%)/36 (20%)/12 (6.6%) were classified into the low/intermediate/high AML probability groups, and each group included 1 (0.7%)/3 (8.3%)/6 (50%) fp-AMLs, respectively, leading to the area under the curve for predicting AML of 0.889. Surgery was commonly opted in the low and intermediate AML probability groups (84% and 64%, respectively) for initial management, while surveillance was selected in the high AML probability group (63%). During the 56-month follow-up, 36 (82%) of 44 patients initially surveyed, including 13 of 18 (72%), 6 of 7 (86%), and 17 of 19 (89%) in the low/intermediate/high AML probability groups, respectively, continued surveillance without any progression. This study confirmed the high diagnostic accuracy for differentiating fp-AMLs. These findings may help in the management of patients with SRMs.

SPINNED: Simulation-based physics-informed neural network for deconvolution of dynamic susceptibility contrast MRI perfusion data.

To propose the simulation-based physics-informed neural network for deconvolution of dynamic susceptibility contrast (DSC) MRI (SPINNED) as an alternative for more robust and accurate deconvolution compared to existing methods. The SPINNED method was developed by generating synthetic tissue residue functions and arterial input functions through mathematical simulations and by using them to create synthetic DSC MRI time series. The SPINNED model was trained using these simulated data to learn the underlying physical relation (deconvolution) between the DSC-MRI time series and the arterial input functions. The accuracy and robustness of the proposed SPINNED method were assessed by comparing it with two common deconvolution methods in DSC MRI data analysis, circulant singular value decomposition, and Volterra singular value decomposition, using both simulation data and real patient data. The proposed SPINNED method was more accurate than the conventional methods across all SNR levels and showed better robustness against noise in both simulation and real patient data. The SPINNED method also showed much faster processing speed than the conventional methods. These results support that the proposed SPINNED method can be a good alternative to the existing methods for resolving the deconvolution problem in DSC MRI. The proposed method does not require any separate ground-truth measurement for training and offers additional benefits of quick processing time and coverage of diverse clinical scenarios. Consequently, it will contribute to more reliable, accurate, and rapid diagnoses in clinical applications compared with the previous methods including those based on supervised learning.

Pathophysiologic Mapping of Chronic Liver Diseases With Longitudinal Multiparametric MRI in Animal Models.

Chronic liver diseases (CLDs) have diverse etiologies. To better classify CLDs, we explored the ability of longitudinal multiparametric MRI (magnetic resonance imaging) in depicting alterations in liver morphology, inflammation, and hepatocyte and macrophage activity in murine high-fat diet (HFD)- and carbon tetrachloride (CCl4)-induced CLD models. Mice were either untreated, fed an HFD for 24 weeks, or injected with CCl4 for 8 weeks. Longitudinal multiparametric MRI was performed every 4 weeks using a 7 T MRI scanner, including T1/T2 relaxometry, morphological T1/T2-weighted imaging, and fat-selective imaging. Diffusion-weighted imaging was applied to assess fibrotic remodeling and T1-weighted and T2*-weighted dynamic contrast-enhanced MRI and dynamic susceptibility contrast MRI using gadoxetic acid and ferucarbotran to target hepatocytes and the mononuclear phagocyte system, respectively. Imaging data were associated with histopathological and serological analyses. Principal component analysis and clustering were used to reveal underlying disease patterns. The MRI parameters significantly correlated with histologically confirmed steatosis, fibrosis, and liver damage, with varying importance. No single MRI parameter exclusively correlated with 1 pathophysiological feature, underscoring the necessity for using parameter patterns. Clustering revealed early-stage, model-specific patterns. Although the HFD model exhibited pronounced liver fat content and fibrosis, the CCl4 model indicated reduced liver fat content and impaired hepatocyte and macrophage function. In both models, MRI biomarkers of inflammation were elevated. Multiparametric MRI patterns can be assigned to pathophysiological processes and used for murine CLD classification and progression tracking. These MRI biomarker patterns can directly be explored clinically to improve early CLD detection and differentiation and to refine treatments.

Evaluation of Cervical Vertebral Motion and Foraminal Changes During the Spurling Test Using Zero Echo Time MRI and CT Micromotion Analysis.

Clinical experimental diagnostic study. The objective of the study was to investigate cervical spine dynamics including changes of the cervical foramina in patients experiencing intermittent arm radiculopathy. Cervical foraminal stenosis is a frequent cause of radicular arm pain. The Spurling test, while specific, lacks the precision to identify symptomatic nerve roots. The relationship between vertebral motion, foraminal changes, and radiculopathy during a Spurling test remains underexplored. Ten patients with positive Spurling tests and MRI-confirmed one or two level cervical foraminal stenosis were scanned using the Dynamic MRI Compression System (DMRICS) enabling a simulated Spurling test inside the MRI gantry of a 3T MRI scanner with a dedicated neck coil. First, a relaxed image acquisition was undertaken followed by slowly applying the Spurling test until the patient reported aggravation of radiculopathy or discomfort, where the next image series was taken. Zero Echo Time (ZTE) MRI was employed to obtain CT-like images. The images were thereafter analyzed using the Sectra® CT-based Micromotion Analysis (CTMA) software for motion analysis. The C4/C5 level exhibited the most significant movements both in translation and rotation, with less movements observed in C5-6 and C6-C7 levels. No uniform pattern emerged that differentiated suspected stenotic levels from non-suspected levels. Despite relatively small vertebral movements, 9/10 of patients reported arm pain during provocation, indicating extremely narrow margins of tolerance. This study demonstrates the utility of ZTE MRI and CTMA in detecting subtle yet clinically relevant vertebral motions influencing the foramina in the cervical spine during the Spurling maneuver. These findings could lead to better understanding and potentially improved diagnostic strategies for cervical foraminal stenosis, although further research with a larger cohort is necessary to confirm these results.

Validation of Dynamic 3D MRI for Urodynamics Assessment Using an Anatomically Realistic In Vitro Model of the Bladder.

Lowery urinary tract symptoms (LUTS) affect a large majority of the aging population. 3D Dynamic MRI shows promise as a noninvasive diagnostic tool that can assess bladder anatomy and function (urodynamics) while overcoming challenges associated with current urodynamic assessment methods. However, validation of this technique remains an unmet need. In this study, an anatomically realistic, bladder-mimicking in vitro flow model was created and used to systematically benchmark 3D dynamic MRI performance using a highly controllable syringe pump. Time-resolved volumes of the synthetic bladder model were obtained during simulated filling and voiding events and used to calculate volumetric flowrate. During MRI acquisitions, pressure during each event was recorded and used to create PV loops for work assessment. Error between control and MRI-derived volume for voiding and filling events exhibited 3.36% and 4.66% differences, respectively. A slight increase in average error was observed for MRI-derived flowrate when compared to the control flowrate (4.90% and 7.67% for voiding and filling, respectively). Overall, average error in segmented volumes increased with decreasing volume flowrate. Pressure drops were observed during voiding. Pressure increased during filling. Enhanced validation of novel 3D MRI urodynamics is achieved by using high-resolution PIV for visualizing and quantifying velocity inside the bladder model, which is not currently possible with 3D Dynamic MRI.

Formant indicators of «velarization». Part I

This article discusses the problem of determining velarization from acoustic data and its relationship to articulation. The aim of the study is to identify the range of formants by which «velarization» can be determined, as well as to determine the location of the highest point of localization of the part of the back of the tongue of the relative palatine arch with this articulation, modeling the sound quality of a specific consonantal sound type. In the course of the study, the methods used at the V.M. Nadelyaev LFEI of the sector of languages of the peoples of Siberia of the IFL SB RAS (Novosibirsk), as well as in the LEFI of the Department of Foreign Languages of the AmSU (Blagoveshchensk). The object of the study is dynamic speech. The subject of the study is «velarization» in languages of different families. The material for the analysis was static and dynamic MRI scans and audio recordings recorded at different times by employees (including the author of this work) of the V.M. Nadelyaev LEFI, made on time and after tomography from the appropriate media. Scientific novelty and theoretical significance of the study: the correlation between F2 , articulation and auditory perception of amplifying articulation of hardness – “velarization” is presented for the first time. The materials and results of the research can be used to develop textbooks on general phonetics, at seminars on dynamic speech analysis, and when writing scientific articles on experimental phonetics. The main conclusions presented in this paper are: 1) the acoustic effect of “velarization” is achieved not only as a result of lifting the back of the tongue to the soft palate not in guttural consonants (velarization), but also between the last third of the second half of the hard palate (prevelarization); 2) correlation analysis of somatic and acoustic material revealed the dependence of format indicators on a certain articulation; 3) a possible range of “velarization” in consonants has been identified – F2 = 1500 Hz – 550 Hz; 4) in the range from 1500 Hz to 1301 Hz, velarization sounds slightly “softer” by ear – a prevelarized consonant than from 1300 Hz to 550 Hz – a velarized consonant. 

Dynamic contrast-enhanced MR imaging in identifying active anal fistula after surgery

BackgroundIt is challenging to identify residual or recurrent fistulas from the surgical region, while MR imaging is feasible. The aim was to use dynamic contrast-enhanced MR imaging (DCE-MRI) technology to distinguish between active anal fistula and postoperative healing (granulation) tissue.MethodsThirty-six patients following idiopathic anal fistula underwent DCE-MRI. Subjects were divided into Group I (active fistula) and Group IV (postoperative healing tissue), with the latter divided into Group II (≤ 75 days) and Group III (> 75 days) according to the 75-day interval from surgery to postoperative MRI reexamination. MRI classification and quantitative analysis were performed. Correlation between postoperative time intervals and parameters was analyzed. The difference of parameters between the four groups was analyzed, and diagnostic efficiency was tested by receiver operating characteristic curve.ResultsWash-in rate (WI) and peak enhancement intensity (PEI) were significantly higher in Group I than in Group II (p = 0.003, p = 0.040), while wash-out rate (WO), time to peak (TTP), and normalized signal intensity (NSI) were opposite (p = 0.031, p = 0.007, p = 0.010). Area under curves for discriminating active fistula from healing tissue within 75 days were 0.810 in WI, 0.708 in PEI, 0.719 in WO, 0.783 in TTP, 0.779 in NSI. All MRI parameters were significantly different between Group I and Group IV, but not between Group II and Group III, and not related to time intervals.ConclusionIn early postoperative period, DCE-MRI can be used to identify active anal fistula in the surgical area.Trial registrationChinese Clinical Trial Registry: ChiCTR2000033072.

PREFUL MRI for Monitoring Perfusion and Ventilation Changes after Elexacaftor-Tezacaftor-Ivacaftor Therapy for Cystic Fibrosis: A Feasibility Study.

Purpose To assess the feasibility of monitoring the effects of elexacaftor-tezacaftor-ivacaftor (ETI) therapy on lung ventilation and perfusion in people with cystic fibrosis (CF), using phase-resolved functional lung (PREFUL) MRI. Materials and Methods This secondary analysis of a multicenter prospective study was carried out between August 2020 and March 2021 and included participants 12 years or older with CF who underwent PREFUL MRI, spirometry, sweat chloride test, and lung clearance index assessment before and 8-16 weeks after ETI therapy. For PREFUL-derived ventilation and perfusion parameter extraction, two-dimensional coronal dynamic gradient-echo MR images were evaluated with an automated quantitative pipeline. T1- and T2-weighted MR images and PREFUL perfusion maps were visually assessed for semiquantitative Eichinger scores. Wilcoxon signed rank test compared clinical parameters and PREFUL values before and after ETI therapy. Correlation of parameters was calculated as Spearman ρ correlation coefficient. Results Twenty-three participants (median age, 18 years [IQR: 14-24.5 years]; 13 female) were included. Quantitative PREFUL parameters, Eichinger score, and clinical parameters (lung clearance index = 21) showed significant improvement after ETI therapy. Ventilation defect percentage of regional ventilation decreased from 18% (IQR: 14%-25%) to 9% (IQR: 6%-17%) (P = .003) and perfusion defect percentage from 26% (IQR: 18%-36%) to 19% (IQR: 13%-24%) (P = .002). Areas of matching normal (healthy) ventilation and perfusion increased from 52% (IQR: 47%-68%) to 73% (IQR: 61%-83%). Visually assessed perfusion scores did not correlate with PREFUL perfusion (P = .11) nor with ventilation-perfusion match values (P = .38). Conclusion The study demonstrates the feasibility of PREFUL MRI for semiautomated quantitative assessment of perfusion and ventilation changes in response to ETI therapy in people with CF. Keywords: Pediatrics, MR-Functional Imaging, Pulmonary, Lung, Comparative Studies, Cystic Fibrosis, Elexacaftor-Tezacaftor-Ivacaftor Therapy, Fourier Decomposition, PREFUL, Free-Breathing Proton MRI, Pulmonary MRI, Perfusion, Functional MRI, CFTR, Modulator Therapy, Kaftrio Clinical trial registration no. NCT04732910 Supplemental material is available for this article. © RSNA, 2024.

Assessment of cervical spondylosis by dynamic MRI and its advantages over routine MRI

Background and objectives. Cervical spondylosis is an age-related condition that influences the various components of the spine. Attributed to its exceptional tissue contrast, magnetic resonance imaging (MRI) is the preferred diagnostic modality for assessing cervical spondylosis. Dynamic MRI examination adds diagnostic information obtained from imaging the patient in flexion and extension. Our study had the purpose of evaluating the flexion-extension MRI’s diagnostic utility. Materials and methods. 40 patients with cervical spondylosis joined our prospective cross-sectional study. The patients were examined by flexion and extension sagittal T2 weighted images (Dynamic MRI) in addition to static MRI cervical spine protocol. The study was carried out in our department and lasted for two years. Results. Total central spinal stenosis (TCSS) was considerably higher in extension in comparison to neutral MRI (Mean ± SD =6.1± 1.45 compared to 4.7 ± 1.29) (p&lt;0.001) showing that extension raises the severity of the cervical spinal stenosis. TCSS was significantly decreased in flexion compared to neutral MRI (Mean ± SD = 3.2 ± 0.79 compared to 4.7 ± 1.29) (p&lt;0.001) assuming flexion reduces the radiological severity of stenosis. Conclusion. Dynamic MRI is a valuable imaging modality. It provides useful information by highlighting more central spinal stenosis, particularly in the extension position, which enhances the treatment regimens for patients with cervical spondylosis.

An estimation of the biomechanical properties of the continent and incontinent woman bladder via inverse finite element analysis.

Stress urinary incontinence often results from pelvic support structures' weakening or damage. This dysfunction is related to direct injury of the pelvic organ's muscular, ligamentous or connective tissue structures due to aging, vaginal delivery or increase of the intra-abdominal pressure, for example, defecation or due to obesity. Mechanical changes alter the soft tissues' microstructural composition and therefore may affect their biomechanical properties. This study focuses on adapting an inverse finite element analysis to estimate the in vivo bladder's biomechanical properties of two groups of women (continent group (G1) and incontinent group (G2)). These properties were estimated based on MRI, by comparing measurement of the bladder neck's displacements during dynamic MRI acquired in Valsalva maneuver with the results from inverse analysis. For G2, the intra-abdominal pressure was adjusted after applying a 95% impairment to the supporting structures. The material parameters were estimated for the two groups using the Ogden hyperelastic constitutive model. Finite element analysis results showed that the bladder tissue of women with stress urinary incontinence have the highest stiffness (α1 = 0.202 MPa and µ1 = 7.720 MPa) approximately 47% higher when compared to continent women. According to the bladder neck's supero-inferior displacement measured in the MRI, the intra-abdominal pressure values were adjusted for the G2, presenting a difference of 20% (4.0 kPa for G1 and 5.0 kPa for G2). The knowledge of the pelvic structures' biomechanical properties, through this non-invasive methodology, can be crucial in the choice of the synthetic mesh to treat dysfunction when considering personalized options.

Comparison of urethral parameters in females presenting cystoceles with and without stress urinary incontinence based on dynamic magnetic resonance imaging: are they different?

To compare urethral parameters between cystocele patients with and without stress urinary incontinence (SUI) and explore factors influencing SUI in cystocele patients via dynamic MRI. The two-dimensional parameters evaluated included the paravaginal defects, levator ani muscle defects, urethral length, urethral funnel shape, bladder neck funnel width, bladder neck funnel depth, urethral angle, posterior vesicourethral angle, and anterior bladder protrusion. The three-dimensional parameters included the proximal urethra rotation angle, the distal urethra rotation angle, bladder neck mobility, urethral midpoint mobility, and externalurethralmeatus mobility. The independent samples t test was used for continuous variables, and the chi-square test was used for categorical variables. Binary logistic regression was used to identify factors independently associated with SUI in cystocele patients. The baseline parameters were similar between the 2 groups. Cystocele patients with SUI had a significantly higher point Aa (1.63 ± 1.06cm vs. 0.81 ± 1.51cm, p = 0.008); more anterior bladder protrusion (33.3% vs. 11.4%, p = 0.017); greater bladder neck mobility (36.38 ± 11.46mm vs. 28.81 ± 11.72mm, p = 0.005); mid-urethral mobility (22.94 ± 6.50mm vs. 19.23 ± 6.65mm, p = 0.014); and external urethral meatus mobility (22.42 ± 8.16mm vs. 18.03 ± 8.51mm, p = 0.022) than did cystocele patients without SUI. The other urethral parameters were similar in the groups (p > 0.05). Binary logistic regression showed that bladder neck mobility was independently associated with SUI in females with cystoceles (odds ratio, 1.06; 95% CI 1.015-1.107; p = 0.009). Cystocele patients with SUI have a higher point Aa, more anterior bladder protrusion, and greater urethral mobility than those without SUI. Bladder neck mobility is independently associated with SUI in females with cystoceles. NCT03146195.

Quantitative Characterization of Respiratory Patterns on Dynamic Higher Temporal Resolution MRI to Stratify Postacute Covid-19 Patients by Cardiopulmonary Symptom Burden.

Postacute Covid-19 patients commonly present with respiratory symptoms; however, a noninvasive imaging method for quantitative characterization of respiratory patterns is lacking. To evaluate if quantitative characterization of respiratory pattern on free-breathing higher temporal resolution MRI stratifies patients by cardiopulmonary symptom burden. Prospective analysis of retrospectively acquired data. A total of 37 postacute Covid-19 patients (25 male; median [interquartile range (IQR)] age: 58 [42-64] years; median [IQR] days from acute infection: 335 [186-449]). 0.55 T/two-dimensional coronal true fast imaging with steady-state free precession (trueFISP) at higher temporal resolution. Patients were stratified into three groups based on presence of no (N = 11), 1 (N = 14), or ≥2 (N = 14) cardiopulmonary symptoms, assessed using a standardized symptom inventory within 1 month of MRI. An automated lung postprocessing workflow segmented each lung in each trueFISP image (temporal resolution 0.2 seconds) and respiratory curves were generated. Quantitative parameters were derived including tidal lung area, rates of inspiration and expiration, lung area coefficient of variability (CV), and respiratory incoherence (departure from sinusoidal pattern) were. Pulmonary function tests were recorded if within 1 month of MRI. Qualitative assessment of respiratory pattern and lung opacity was performed by three independent readers with 6, 9, and 23 years of experience. Analysis of variance to assess differences in demographic, clinical, and quantitative MRI parameters among groups; univariable analysis and multinomial logistic regression modeling to determine features predictive of patient symptom status; Akaike information criterion to compare the quality of regression models; Cohen and Fleiss kappa (κ) to quantify inter-reader reliability. Two-sided 5% significance level was used. Tidal area and lung area CV were significantly higher in patients with two or more symptoms than in those with one or no symptoms (area: 15.4 cm2 vs. 12.9 cm2 vs. 12.8 cm2 ; CV: 0.072, 0.067, and 0.058). Respiratory incoherence was significantly higher in patients with two or more symptoms than in those with one or no symptoms (0.05 vs. 0.043 vs. 0.033). There were no significant differences in patient age (P = 0.19), sex (P = 0.88), lung opacity severity (P = 0.48), or pulmonary function tests (P = 0.35-0.97) among groups. Qualitative reader assessment did not distinguish between groups and showed slight inter-reader agreement (κ = 0.05-0.11). Quantitative respiratory pattern measures derived from dynamic higher-temporal resolution MRI have potential to stratify patients by symptom burden in a postacute Covid-19 cohort. 3 TECHNICAL EFFICACY: Stage 3.

Assessment of pelvic organ prolapse with the Pelvic Inclination Correction System: defining the normal range and threshold to pathology.

To define the normal range and threshold values for pathologic prolapse on MRI using the PICS line and assess its correlation with the pubococcygeal line (PCL). This prospective, IRB-approved study included 20 nulliparous volunteers and 18 prolapse patients (POP-Q Stage ≥ 2). Organ positions (bladder, cervix, anorectal junction) relative to PICS and PCL were measured on dynamic MRI. Differences in organ position were compared. Receiver-operating characteristic (ROC) analysis was performed to identify cutoff values for prolapse using the PICS line. The correlation between PICS and PCL measurements was tested with Spearman's rank correlation. In volunteers, median bladder and cervix positions measured to the PICS at rest were -2.7cm and -5.3cm compared to -1.9cm and -2.7cm in patients (p < 0.001). During straining, bladder and cervix were at -0.9cm and -3.2cm in volunteers versus + 2.5cm and + 2.5cm in patients (p < 0.001). Correlation was strong for PICS and PCL measurements for all three compartments (δ = 0.883-0.970, p ≤ 0.001). AUCs of PICS for the anterior and middle compartment were 0.98 (95% confidence interval [CI] 0.96-1.00, p < 0.001) and 0.96 (95% CI 0.89-1.00, p < 0.001) for differentiating patients from healthy volunteers. AUC for the posterior compartment was 0.76 (95% CI 0.57-0.96, p = 0.034). PICS measurements reliably differentiate patients from volunteers in the anterior and middle compartment. Future studies need to identify a reliable threshold for the posterior compartment. PICS and PCL measurements are strongly correlated.