Simultaneous T1, T2, and T2* Mapping of Carotid Plaque: The SIMPLE* Technique.

Background Quantitative T1, T2, and T2* measurements of carotid atherosclerotic plaque are important in evaluating plaque vulnerability and monitoring its progression. Purpose To develop a sequence to simultaneously quantify T1, T2, and T2* of carotid plaque. Materials and Methods The simultaneous T1, T2, and T2* mapping of carotid plaque (SIMPLE*) sequence is composed of three modules with different T2 preparation pulses, inversion-recovery pulses, and acquisition schemas. Single-echo data were used for T1 and T2 quantification, while the multiecho (ME) data were used for T2* quantification. The quantitative accuracy of SIMPLE* was tested in a phantom study by comparing its measurements with those of reference standard sequences. In vivo feasibility of the technique was prospectively evaluated between November 2020 and February 2022 in healthy volunteers and participants with carotid atherosclerotic plaque. The Pearson or Spearman correlation test, Student t test, and Wilcoxon rank-sum test were used. Results T1, T2, and T2* estimated with SIMPLE* strongly correlated with inversion-recovery spin-echo (SE) (correlation coefficient [r] = 0.99), ME-SE (r = 0.99), and ME gradient-echo (r = 0.99) sequences in the phantom study. In five healthy volunteers (mean age, 25 years ± 3 [SD]; three women), measurements were similar between SIMPLE* and modified Look-Locker inversion recovery, or MOLLI (1151 msec ± 71 vs 1098 msec ± 64; P = .14), ME turbo SE (31 msec ± 1 vs 31 msec ± 1; P = .32), and ME turbo field echo (24 msec ± 2 vs 25 msec ± 2; P = .19). In 18 participants with carotid plaque (mean age, 65 years ± 9; 16 men), quantitative T1, T2, and T2* of plaque components were consistent with their signal characteristics on multicontrast images. Conclusion A quantitative technique for simultaneous T1, T2, and T2* mapping of carotid plaque with 100-mm3 coverage and 0.8-mm3 resolution was developed using the proposed SIMPLE* sequence and demonstrated high accuracy and in vivo feasibility. © RSNA, 2023 Supplemental material is available for this article.

Single breath-hold three-dimensional whole-heart T2 mapping with low-rank plus sparse reconstruction.

The purpose of the current study was to develop and evaluate a three-dimensional single Breath-hOLd cardiac T2 mapping sequence (3D BOLT) with low-rank plus sparse (L + S) reconstruction for rapid whole-heart T2 measurement. 3D BOLT collects three highly accelerated electrocardiogram-triggered volumes with whole-heart coverage, all within a single 12-heartbeat breath-hold. Saturation pulses are performed every heartbeat to prepare longitudinal magnetization before T2 preparation (T2 -prep) or readout, and the echo time of T2 -prep is varied per volume for variable T2 weighting. Accelerated volumes are reconstructed jointly by an L + S algorithm. 3D BOLT was optimized and validated against gradient spin echo (GraSE) and a previously published approach (three-dimensional free-breathing cardiac T2 mapping [3DFBT2]) in both phantoms and human subjects (11 healthy subjects and 10 patients). The repeatability of 3D BOLT was validated on healthy subjects. Retrospective experiments indicated that 3D BOLT with 4.2-fold acceleration achieved T2 measurements comparable with those obtained with fully sampled data. T2 measured in phantoms using 3D BOLT demonstrated good accuracy and precision compared with the reference (R2 > 0.99). All in vivo imaging was successful and the average left ventricle T2 s measured by GraSE, 3DFBT2, and 3D BOLT were comparable and consistent for all healthy subjects (47.0 ± 2.3 vs. 47.7 ± 2.7 vs. 48.4 ± 1.8 ms) and patients (50.8 ± 3.0 vs. 48.6 ± 3.9 vs. 49.1 ± 3.7 ms), respectively. Myocardial T2 measured by 3D BOLT had excellent agreement with 3DFBT2 and there was no significant difference in mean, standard deviation, and coefficient of variation. 3D BOLT showed excellent repeatability (intraclass correlation coefficient: 0.938). The proposed 3D BOLT achieved whole-heart T2 mapping in a single breath-hold with good accuracy, precision, and repeatability on T2 measurements.

Subtractionless compressed-sensing-accelerated whole-body MR angiography using two-point Dixon fat suppression with single-pass half-reduced contrast dose: feasibility study and initial experience.

PURPOSE: To investigate the feasibility and clinical utility of a compressed-sensing-accelerated subtractionless whole-body MRA (CS-WBMRA) protocol with only contrast injection for suspected arterial diseases, by comparison to conventional dual-pass subtraction-based whole-body MRA (conventional-WBMRA) and available computed tomography angiography (CTA). MATERIALS AND METHODS: This prospective study assessed 86 patients (mean age, 56 years ± 16.4 [standard deviation]; 25 women) with suspected arterial diseases from May 2021 to December 2022, who underwent CS-WBMRA (n = 48, mean age, 55.9 years ± 16.4 [standard deviation]; 25 women) and conventional-WBMRA (n = 38, mean age, 48 years ± 17.4 [standard deviation]; 20 women) on a 3.0 T MRI after random group assignment based on the chronological order of enrolment. Of all enrolled patients administered the CS-WBMRA protocol, 35% (17/48) underwent CTA as required by clinical demands. Two experienced radiologists independently scored the qualitative image quality and venous enhancement contamination. Quantitative image assessment was carried out by determining and comparing the apparent signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) of four representative arterial segments. The total examination time and contrast-dose were also recorded. The independent samples t-test or the Wilcoxon rank sum test was used for statistical analysis. RESULTS: The overall scores of CS-WBMRA outperformed those of conventional-WMBRA (3.40 ± 0.60 vs 3.22 ± 0.55, P < 0.001). In total, 1776 and 1406 arterial segments in the CS-WBMRA and conventional-WBMRA group were evaluated. Qualitative image scores for 7 (of 15) vessel segments in the CS-WMBRA group had statistically significantly increased values compared to those of the conventional-WBMRA groups (P < 0.05). Scores from the other 8 segments showed similar image quality (P > 0.05) between the two protocols. In the quantitative analysis, overall apparent SNRs were significantly higher in the conventional-WBMRA group than in the CS-WBMRA group (214.98 ± 136.05 vs 164.90 ± 118.05; P < 0.001), while overall apparent CNRs were not significantly different in these two groups (CS vs conventional: 107.13 ± 72.323 vs 161.24 ± 118.64; P > 0.05). In the CS-WBMRA group, 7 of 1776 (0.4%) vessel segments were contaminated severely by venous enhancement, while in the convention-WBMRA group, 317 of 1406 (23%) were rated as severe contamination. In the CS-WBMRA group, total examination and reconstruction times were only 7 min and 10 min, respectively, vs 20 min and < 30 s for the conventional WBMRA group, respectively. The contrast agent dose used in the CS-WBMRA protocol was reduced by half compared to conventional-WBMRA protocol (18.7 ± 3.5 ml vs 37.2 ± 5.4 ml, P = 0.008). CONCLUSION: The CS-WBMRA protocol provides excellent image quality and sufficient diagnostic accuracy for whole-body arterial disease, with relatively faster workflow and half-dose reduction of contrast agent, which has greater potential in clinical practice compared with conventional-WBMRA.

Optimization of the Contrast Agent Injection Protocol for Carotid Artery Dynamic Contrast-Enhanced Magnetic Resonance Imaging.

BACKGROUND: The injection protocol used in previous carotid artery dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) studies varied. PURPOSE: To investigate the effect of contrast injection protocol and optimize this protocol for carotid artery DCE-MRI. STUDY TYPE: Prospective. SUBJECTS: Digital phantom and seven patients with carotid atherosclerosis. FIELD STRENGTH/SEQUENCE: 3 T, spoiled gradient recalled echo sequence. ASSESSMENT: Different injection doses (0.01-0.3 mmol/kg) and effective injection rates (0.01-1 mmol/sec) were tested using a digital carotid plaque phantom considering the contrast pharmacokinetics, DCE-MRI imaging, contrast variation and flow-related imaging artifacts, random time delay between the contrast injection and image acquisition, and pharmacokinetic analysis process. For each injection protocol, combining the root mean square relative error (RMSRE) of the measured K trans and v P maps within the adventitial vasa vasorum from 10 tested time delays by the root mean square produced RMSREoverall-vv which was used to measure the overall accuracy of the pharmacokinetic parameters. In vivo validation was performed on seven patients with carotid atherosclerosis by imaging them twice using the traditional commonly used protocol and the recommended protocol found by simulation. STATISTICAL TEST: Student's t-test, chi-square test, and paired t-test, P < 0.05 was considered statistically significant. RESULTS: A low region of RMSREoverall-vv with the combination of medium injection dose and low effective injection rate was found. The protocol with injection dose of 0.07 mmol/kg and effective injection rate of 0.06 mmol/sec achieved the minimal RMSREoverall-vv (4.29%), thus was recommended, which showed more accurate arterial input function. Coinciding with the simulation results, this recommended protocol in in vivo experiments produced significantly fewer image artifacts, lower K trans and v P (P all <0.05) than traditional protocol which overestimated these parameters in simulation. DATA CONCLUSION: The contrast injection protocol influenced the accuracy of the pharmacokinetics parameter estimation in carotid artery DCE-MRI. The injection protocol with injection dose of 0.07 mmol/kg and effective injection rate of 0.06 mmol/sec was recommended. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY STAGE: 1.

Value of 18F-FDG PET/MR Imaging in the Early Evaluation of Treatment Response following Radiofrequency Ablation of Liver Cancer in a Rabbit Model.

PURPOSE: To test the hypothesis that 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) and magnetic resonance (MR) imaging can detect early residual tumor following radiofrequency (RF) ablation of liver cancer using a VX2 tumor model. MATERIALS AND METHODS: Twenty-four rabbits with VX2 liver tumors were randomly divided into 3 groups (n = 8/group): Group 1 without RF ablation treatment, Group 2 with complete ablation, and Group 3 with partial ablation. An 18F-FDG PET/MR imaging scan was obtained within 2 hours after RF ablation. The maximum standardized uptake values (SUV) of the nontreated liver tumor, benign periablational enhancement (BPE), residual tumor, ablated tumor, and adjacent liver parenchyma and mean SUV of the normal liver were measured. The ratios of maximum SUV for these targets to the mean SUV of the normal liver (TNR) were calculated and compared. RESULTS: The mean TNR of the nontreated liver tumors in Group 1 was significantly greater than that of the adjacent liver parenchyma (8.68 ± 0.71 vs 1.89 ± 0.26, P < .001). In Group 2, the mean TNR of BPE was significantly greater than that of the adjacent liver parenchyma (2.85 ± 0.20 vs 1.86 ± 0.25, P < .001). In Group 3, the mean TNR of the residual tumor was significantly greater than that of BPE (8.64 ± 0.59 vs 2.78 ± 0.23, P < .001), which was significantly greater than that of completely ablated tumor (2.78 ± 0.23 vs 0.50 ± 0.06, P < .001). CONCLUSIONS: 18F-FDG PET/MR imaging may serve as a promising imaging tool for the early detection of viable residual tumors due to incomplete tumor ablation.

Integrated head and neck imaging of symptomatic patients with stroke using simultaneous non-contrast cardiovascular magnetic resonance angiography and intraplaque hemorrhage imaging as compared with digital subtraction angiography.

BACKGROUND: Both stenosis rate and intraplaque hemorrhage (IPH) are important predictors of stroke risk. Simultaneous non-contrast angiography and intraplaque hemorrhage (SNAP) cardiovascular magnetic resonance (CMR) imaging can detect both stenosis rate and IPH. We aimed to evaluate consistency between SNAP and digital subtraction angiography (DSA) to assess symptomatic patients with stroke and explore the performance of SNAP to identify IPH and the clinical factors associated with IPH. METHODS: Eighty-one symptomatic patients with stroke, admitted to Wuhan Union Hospital who underwent CMR high-resolution vessel wall imaging (HR-VWI) and SNAP, were retrospectively identified. For patients who received interventional therapy, the imaging functions of SNAP and HR-VWI were compared with DSA. The diameters of the intracranial and carotid vessels were measured, and stenotic vessels were identified. The consistency of SNAP and HR-VWI in identifying IPH was also examined, and the correlations between IPH and clinical factors were analyzed. RESULTS: SNAP was more consistent with DSA than HR-VWI in measuring vascular stenosis (intraclass correlation coefficient [ICC]SNAP-DSA = 0.917, ICC HR-VWI-DSA = 0.878). Regarding the diameter measurements of each intracranial and carotid vessel segment, SNAP was superior or similar to HR-VWI, and both were consistent with DSA in the measurement of major intracranial vascular segments. HR-VWI and SNAP exhibited acceptable agreement in identifying IPH (Kappa = 0.839, 95% confidence interval [CI]: 0.704-0.974). Patients who underwent interventional therapy had a higher plaque burden (P < 0.001). Patients with IPH had lower levels of high-density lipoprotein cholesterol (HDL) (P = 0.038) and higher levels of blood glucose (P = 0.007) and cystatin C (P = 0.040). CONCLUSIONS: CMR SNAP is consistent with DSA in measuring vessel diameters and identifying atherosclerosis stenosis in each intracranial and carotid vessel segment. SNAP is also a potential alternative to HR-VWI in identifying stenosis and IPH.

Assessment of acute traumatic cervical spinal cord injury using conventional magnetic resonance imaging in combination with diffusion tensor imaging-tractography: a retrospective comparative study.

PURPOSE: The application of conventional magnetic resonance imaging (MRI) in combination with diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) to diagnose acute traumatic cervical SCI has not been studied. This study explores the role of MRI with DTI-DTT in the diagnosis of acute traumatic cervical spinal cord injury (SCI). METHODS: Thirty patients with acute traumatic cervical SCI underwent conventional MRI and DTI-DTT. Conventional MRI was used to detect the intramedullary lesion length (IMLL) and intramedullary hemorrhage length (IMHL). DTI was used to detect the spinal cord's fractional anisotropy (FA) and apparent diffusion coefficient value, and DTT detected the imaginary white matter fiber volume and the connection rates of fiber tractography (CRFT). Patients' neurological outcome was determined using the American Spinal Injury Association (ASIA) Impairment Scale (AIS) grades. RESULTS: Patients were divided into group A (without AIS grade conversion) and group B (with AIS grade conversion). The IMLL and IMHL of group A were significantly higher than those of group B. The FA and CRFT of group A were significantly lower than those of group B. The final AIS grade was negatively correlated with the IMLL and IMHL, and positively correlated with the FA and CRFT. According to imaging features based on conventional MRI and DTI-DTT, we propose a novel classification and diagnostic procedure. CONCLUSIONS: The combination of conventional MRI with DTI-DTT is a valid diagnostic approach for SCI. Lower IMLL and IMHL, and higher FA value and CRFT are linked to better neurological outcomes.

Enhancement degree of brain metastases: correlation analysis between enhanced T2 FLAIR and vascular permeability parameters of dynamic contrast-enhanced MRI.

OBJECTIVES: To investigate the correlation between enhancement degrees of brain metastases on contrast-enhanced T2-fluid-attenuated inversion recovery (CE-T2 FLAIR) and vascular permeability parameters of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). METHODS: Thirty-nine patients with brain metastases were prospectively collected. They underwent non-enhanced T2 FLAIR, DCE-MRI, CE-T2 FLAIR, and contrast-enhanced three-dimensional brain volume imaging (CE-BRAVO). Quantitative parameters of DCE-MRI were evaluated for all lesions, which included volume transfer constant (Ktrans), rate constant (Kep), and fractional volume of the extracellular extravascular space (Ve). Contrast ratio (CR) and percentage increase (PI) values of all lesions on CE-T2 FLAIR were also measured. The tumor enhancement degree on CE-T2 FLAIR in relation to CE-BRAVO was visually classified as higher (group A), equal (group B), and lower (group C). RESULTS: A total of 82 brain metastases were evaluated, including 31 in group A, 19 in group B, and 32 in group C. The Ktrans and Kep were negatively correlated with the CR (ρ = - 0.551, p < 0.001 and ρ = - 0.708, p < 0.001, respectively) and PI (ρ = - 0.511, p < 0.001 and ρ = - 0.621, p < 0.001, respectively). The Ktrans and Kep of group A were significantly lower than those of group C (both p < 0.001). No significant difference was found in Ve among the groups (p = 0.327). CONCLUSIONS: The enhancement degree of brain metastases on CE-T2 FLAIR is negatively correlated with Ktrans and Kep values, which indicate that vascular permeability parameters may play an important role in explaining the difference in enhancement between CE-T2 FLAIR and CE-BRAVO. KEY POINTS: • The enhancement degree on CE-T2 FLAIR was negatively correlated with Ktrans and Kep values. • The vascular permeability of brain metastasis accounted for the difference in enhancement degree between CE-T2 FLAIR and CE-BRAVO. • CE-T2 FLAIR is useful for detecting brain metastases with mild disruption of the blood-brain barrier.

The value of multimodality imaging in diagnosis and treatment of cardiac lipoma.

BACKGROUND: Cardiac lipoma is a rare primary tumor in the heart and pericardium. Multimodality imaging methods, especially magnetic resonance imaging (MRI), are crucial in detecting and diagnosing cardiac lipomas. Besides, they are of significant importance in management of cardiac lipomas. The aim of this study was to evaluate the value of multimodality imaging methods in diagnosing and treatment of cardiac lipoma by describing a series of cases of cardiac lipoma. MATERIALS AND METHODS: Data of patients with cardiac lipoma at a local institution were retrospectively collected. Their imaging findings on echocardiography, computed tomography (CT), and cardiac MRI and clinical management were described in detail. RESULTS: 12 patients with cardiac lipoma were retrospectively included with thirteen lipomas found within heart and pericardium. Two patients' lipoma were symptomatic, while lipomas in other 10 patients were found incidentally. Most lipomas were sensitively detected with echocardiography. Accurate diagnoses were achieved with CT and MRI in all cases. Surgical resection was performed in one symptomatic patient due to the obstruction of the left ventricular outflow tract, while the removal of pericardial lipoma in another symptomatic patient was not possible due to diffuse myocardial infiltration observed in MRI. Based on MRI findings, two patients without clinical symptoms also underwent surgery to prevent the risk of detachment of ventricular lipoma with a narrow pedicle in one patient and potential further thinning of the myocardium by pericardial lipoma growth in another patient. CONCLUSIONS: Cardiac lipoma could be sensitively detected and accurately diagnosed with multiple noninvasive imaging tools. Comprehensive evaluation with multimodality imaging methods should also be conducted for better management planning and follow-up in all patients.

Diffusion tensor magnetic resonance imaging of the postoperative spine with metallic implants.

There has been a growing need to understand the mechanism of development of acute spinal cord injury (SCI) and to optimize treatment. The paramagnetic nature of metallic implants has hampered the application of diffusion tensor imaging (DTI) in postsurgical SCI monitoring. We describe here a successful implementation of spinal DTI in postsurgical SCI patients. Data were acquired using a single-shot turbo-spin-echo sequence, where an extra gradient is applied before the refocusing pulse train to eliminate contributions from the non-Carr-Purcell-Meiboom-Gill components following a diffusion preparation block where a single-spin echo scheme is deployed. The DTI images were acquired in axial orientation with a 2 x 2 x 4 mm3 resolution and a total of 18 slices. Diffusion gradients were applied in six directions with b values of 0 and 600 seconds/mm2 . The whole scan took ~10 minutes. The sequence was compared with SENSE-DW-EPI and ZOOM-DW-EPI on a phantom, eight patients with either anterior or posterior titanium alloy implants, and a pork loin with a similar implant. The protocol resulted in dramatically reduced geometric distortions compared with routine imaging sequences, however, the SNR efficiency was compromised. The spinal cord signal displacement was 0.68±1.00 mm (mean±SD, n = 8) for the proposed protocol, and 5.14±3.07 and 2.82±1.60 mm for the SENSE-DW-EPI and ZOOM-DW-EPI sequences, respectively. Fiber tracking was achieved in the presence of implants, which in one case was accompanied by central spinal cord caviation. Mathematical analysis concluded that the proposed protocol would be generally applicable in the spinal cord when the titanium alloy implant is ~15 mm away (<0.5 kHz B0 field drift). The protocol described is capable of DTI in postsurgery SCI patients with metallic implants at sufficient resolution and SNR.

Increased myocardial extracellular volume assessed by cardiovascular magnetic resonance T1 mapping and its determinants in type 2 diabetes mellitus patients with normal myocardial systolic strain.

BACKGROUND: Cardiac magnetic resonance (CMR) T1 mapping and tissue-tracking strain analysis are useful quantitative techniques that can characterize myocardial tissue and mechanical alterations, respectively, in patients with early diabetic cardiomyopathy. The purpose of this study was to assess the left ventricular myocardial T1 value, extracellular volume fraction (ECV), and systolic strain in asymptomatic patients with type 2 diabetes mellitus (T2DM) and their underlying relationships with clinical parameters. METHODS: We recruited 50 T2DM patients (mean age: 55 ± 7 years; 28 males) and 32 sex-, age-and BMI-matched healthy volunteers to undergo contrast-enhanced CMR examinations. The myocardial native T1, post-contrast T1 and ECV values of the left ventricle were measured from T1 and ECV maps acquired using the modified Look-Locker inversion recovery technique. The left ventricular global systolic strain and the strain rates were evaluated using routine cine images and tissue-tracking analysis software. The baseline clinical and biochemical indices were collected before the CMR examination. RESULTS: The myocardial ECV and native T1 values were significantly higher in the diabetic patients than in the controls. (ECV: 27.4 ± 2.5% vs. 24.6 ± 2.2%, p < 0.001; native T1: 1026.9 ± 30.0 ms vs. 1011.8 ± 26.0 ms, p = 0.022). However, the left ventricular global systolic strain, strain rate, volume, myocardial mass, ejection fraction, and left atrial volume were similar between the diabetic patients and the healthy controls. In the diabetic patients, the native T1 values were independently correlated with the hemoglobin A1c levels (standardized ß = 0.368, p = 0.008). The ECVs were independently associated with the hemoglobin A1c levels (standardized ß = 0.389, p = 0.002), angiotensin-converting enzyme inhibitor (ACEI) treatment (standardized ß = - 0.271, p = 0.025) and HCT values (standardized ß = - 0.397, p = 0.001). CONCLUSIONS: Type 2 diabetes mellitus patients with normal myocardial systolic strain exhibit increased native T1 values and ECVs indicative of myocardial extracellular interstitial expansion, which might be related to poor glycemic control. The amelioration of myocardial interstitial matrix expansion might be associated with ACEI treatment. A valid assessment of the association of glucose control and ACEI treatment with myocardial fibrosis requires notably larger trials.

Association between myocardial extracellular volume and strain analysis through cardiovascular magnetic resonance with histological myocardial fibrosis in patients awaiting heart transplantation.

BACKGROUND: Cardiovascular magnetic resonance (CMR)-derived extracellular volume (ECV) and tissue tracking strain analyses are proposed as non-invasive methods for quantifying myocardial fibrosis and deformation. This study sought (1) to histologically validate myocardial ECV against the collagen volume fraction (CVF) measured from tissue samples of patients undergoing heart transplantation and (2) to detect the correlations between myocardial systolic strain and the myocardial ECV and histological CVF in patients undergoing heart transplantation. METHODS: A total of 12 dilated cardiomyopathy (DCM) and 10 ischaemic cardiomyopathy (ICM) patients underwent T1 mapping with the Modified Look Locker Inversion recovery (MOLLI) sequence, T2 mapping and ECV. Myocardial systolic strain, including left ventricular global longitudinal (GLS), circumferential (GCS) and radial strain (GRS), were quantified using CMR cine images with tissue tracking analysis software. Tissue samples were collected from each of 16 segments of the explanted hearts and were stained with picrosirius red for histological CVF quantification. RESULTS: A strong relationship was observed between the global myocardial ECV and histological CVF in the DCM and ICM patients based on a per-patient analysis (r = 0.904 and r = 0.901, respectively, p <  0.001). In the linear mixed-effects regression analysis, ECV correlated well with the histological CVF in the DCM and ICM patients on a per-segment basis (ß = 0.838 and ß = 0.915, respectively, p <  0.001). In the multivariate linear regression analysis, histological CVF was the strongest independent determinant of ECV in the patients awaiting heart transplantation (standardised ß = 0.860, p <  0.001). However, the T2 time, GLS, GCS and GRS showed no significant associations with ECV and CVF in the patients awaiting heart transplantation. CONCLUSIONS: ECV derived from CMR correlated well with histological CVF, indicating its potential as a non-invasive tool for the quantification of myocardial fibrosis. Additionally, impaired myocardial systolic strains were not associated with the ECV and CVF in the patients awaiting heart transplantation.

Evaluation of Mental Disorders Using Proton Magnetic Resonance Spectroscopy in Dialysis and Predialysis Patients.

BACKGROUND/AIMS: Psychological complications are prevalent in patients with chronic kidney disease (CKD). This study aimed to investigate mental disorders in stage 4-5 CKD patients, to detect metabolite concentrations in the brain by proton magnetic resonance spectroscopy (1H-MRS) and to compare the effects of different dialysis therapies on mental disorders in end-stage renal disease (ESRD). METHODS: The sample population was made up of predialysis (13), hemodialysis (HD) (13), and peritoneal dialysis (PD) patients (12). We collected the baseline data of patients' age, sex, hemoglobin (Hb) and parathyroid hormone（PTH） levels. The predialysis patients served as the control group. The psychological status of the three groups was assessed using three psychological scales. 1H-MRS was used to evaluate the relative metabolite concentrations in the bilateral amygdala, hippocampus and unilateral anterior cingulated cortex (ACC). RESULTS: The psychological status was better in HD patients than in predialysis and PD patients. 1H-MRS alterations were predominantly found in the ACC. Choline-containing compounds relative to creatine (Cho/Cr), myo-inositol relative to creatine (MI/Cr) and glutamate and glutamine relative to creatine (Glx/Cr) in the ACC were higher in HD patients. 1H-MRS results were correlated with the baseline data and the scores of psychological scales. CONCLUSIONS: CKD patients showed different types of mental disorders as well as metabolite disturbances in the brain. The metabolite concentrations correlated with the psychological status which was better in HD than in predialytic and PD patients.

Exploring functional connectivity alterations in sudden sensorineural hearing loss: A multilevel analysis.

Sudden sensorineural hearing loss (SSNHL) constitutes an urgent otologic emergency, marked by a rapid decline of at least 30 dB across three consecutive frequencies within 72 h. While previous studies have noted brain region alterations encompassing both auditory and non-auditory areas, this research examines functional connectivity changes across integrity, network, and edge levels in SSNHL. The cohort included 184 participants: 107 SSNHL patients and 77 age- and sex-matched healthy controls. Our investigation comprises: (1) characterization of overall functional connectivity degree across 55 nodes in nine networks (p < 0.05, corrected for false discovery rate), exposing integrity level changes; (2) identification of reduced intranetwork connectivity strength within sensory and attention networks (somatomotor network, auditory network, ventral attention network, dorsal attention network) in SSNHL individuals (p < 0.05, Bonferroni corrected), and reduced internetwork connectivity across twelve distinct subnetwork pairs (p < 0.05, FDR corrected); (3) revelation of increased internetwork connectivity in SSNHL patients, primarily spanning dorsal attention network, fronto parietal network, default mode network, and limbic network, alongside widespread reductions in connectivity patterns among the nine distinct resting-state brain networks. The study further uncovers negative correlations between SSNHL duration and intranetwork connectivity of the auditory network (p < 0.001, R = -0.474), and between Tinnitus Handicap Inventory (THI) scores and internetwork connections linking auditory network and dorsal attention network (p < 0.001, R = -0.331). These observed alterations provide crucial insights into the neural mechanisms underpinning SSNHL and extend our comprehension of the brain's network-level responses to sensory loss. By unveiling the intricate interplay between sensory deprivation, adaptation, and cognitive processes, this study lays the groundwork for future research targeting enhanced diagnosis, treatment, and rehabilitation approaches for individuals afflicted by SSNHL.

Improved visualization of median, ulnar nerves, and small branches in the wrist and palm using contrast-enhanced magnetic resonance neurography.

Background: Magnetic resonance imaging of peripheral nerves in the wrist and palm is challenging due to the small size, tortuous course, complex surrounding tissues, and accompanying blood vessels. The occurrence of carpal palmar lesions leads to edema, swelling, and mass effect, which may further interfere with the display and identification of nerves. Objective: To evaluate whether contrast-enhanced magnetic resonance neurography (ceMRN) improves the visualization of the morphology and pathology of the median, ulnar nerves, and their small branches in the wrist and palm. Design: An observational study. Methods: In total 57 subjects, including 36 volunteers and 21 patients with carpal palmar lesions, were enrolled and underwent ceMRN and non-contrast MRN (ncMRN) examination at 3.0 Tesla. The degree of vascular suppression, nerve visualization, diagnostic confidence, and lesion conspicuity was qualitatively assessed by two radiologists. Kappa statistics were obtained for inter-reader agreement. The signal-to-noise ratio, contrast ratio (CR), and contrast-to-noise ratio (CNR) of the median nerve were measured. The subjective ratings and quantitative measurements were compared between ncMRN and ceMRN. Results: The inter-reader agreement was excellent (k > 0.8) for all qualitative assessments and visualization assessment of each nerve segment. Compared with ncMRN, ceMRN significantly improved vascular suppression in volunteers and patients (both p < 0.001). The ceMRN significantly enhanced nerve visualization of each segment (all p < 0.05) and diagnostic confidence in volunteers and patients (both p < 0.05). The ceMRN improved lesion conspicuity (p = 0.003) in patients. Quantitatively, ceMRN had significantly higher CRs of nerve versus subcutaneous fat, bone marrow, and vessels and CNR of nerve versus vessel than ncMRN (all p < 0.05). Conclusion: The ceMRN significantly improves the visualization of peripheral nerves and pathology in the wrist and palm by robustly suppressing the signals of fat, bone marrow, and especially vessels in volunteers and patients.

Study on the improvement of magnetic resonance imaging and lesion display of small nerves in the wrist and palm using contrast agents Why was the study done? Because the nerves and branches in the wrist and palm are numerous, small, tortuous, and surrounded by muscles, fat, bones, blood vessels and other tissues, it is difficult to show their complete shape with conventional magnetic resonance imaging. Hand lesions often lead to swelling, edema and masses, which interfere with the display of nerves. Therefore, it is difficult to directly diagnose the relationship between the lesions and nerves in clinical practice. What did the researchers do? The research team used contrast agent plus three-dimensional high-resolution magnetic resonance sequence to display the nerves of volunteers and patients with hand lesions, and used subjective and objective evaluation methods to compare the display effect of the sequence on the nerves before and after the use of contrast agent. What did the researchers find? The imaging method of contrast agent plus three-dimensional high-resolution magnetic resonance sequence can reduce the interference of fat, blood vessels, etc. on nerve display, improve the display effect of each nerve segment of the wrist and palm, increase readers' confidence in identifying nerves, and improve the detection of lesions. What do the findings mean? This study verified the feasibility and advantages of using contrast agents for magnetic resonance imaging of nerves in the wrist and palm. It provides a new method for clinical and imaging diagnosis of hand lesions, which can simultaneously display the morphological characteristics of nerves and lesions, reducing the difficulty of clinical diagnosis and improving the efficiency of imaging diagnosis.

Multisequence magnetic resonance neurography of brachial and lumbosacral plexus in chronic inflammatory demyelinating polyneuropathy: correlations with electrophysiological parameters and clinical features.

Background: Chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare and challenging demyelinating disorder. It is necessary to increase our understanding of potential connections between imaging, electromyography, and clinical characteristics. Objective: The aim of this study was to evaluate the relationships between multisequence magnetic resonance neurography (MRN) findings, electrophysiological parameters, and clinical characteristics in CIDP patients. Design: A cross-sectional study. Methods: Overall, 51 CIDP patients underwent MRN of the brachial and lumbosacral plexus, and nerve conduction studies. The inflammatory Rasch-built overall disability scale (I-RODS) questionnaire, CIDP disease activity status (CADS) scale, and muscle strength scores were evaluated by two neurologists. Electrophysiological parameters, clinical information, and multiparameter-MRN were analyzed for correlations. Multiparameter-MRN includes diameter, nerve-to-muscle T2 signal intensity ratio (nT2), contrast-enhanced ratio (CR), fractional anisotropy (FA), and apparent diffusion coefficient (ADC) of bilateral plexus nerve roots. Results: Electrophysiological parameters that were not elicited were significantly higher in the lower extremities than in the upper extremities, and those were higher in sensory nerve conduction than in motor. There were moderate correlations between motor nerve conduction velocity and distal motor latency in nerve diameter, nT2, FA, and ADC, respectively (|r|, 0.45-0.64, p < 0.05). The correlations between CR and sensory nerve conduction velocity and peak latency were moderate, and ADC had a positive correlation with compound motor action potential amplitude (|r|, 0.45-0.63). FA correlated negatively with the course (r = -0.62) and cerebrospinal fluid (CSF) protein (r = -0.41), whereas ADC had correlated positively with CSF protein (r = 0.34). Only CR had a moderately negative correlation with CADS (r's = -0.57). Muscle strength in all extremities was positively correlated with FA (r's range, 0.41-0.49). There was no significant correlation between I-RODS scores and multiparameter-MR. Conclusion: MRN-derived multiparameter [nerve size, nT2, and diffusion tensor imaging (DTI) parameters] could serve as quantitative biomarkers of myelin sheath integrity in CIDP. DTI parameters and CR correlated with clinical characteristics better than morphological parameters-MR for CIDP patients.

Applying the AAPM 293 report to estimate the absorbed dose during head computed tomography: using head circumference for rapid dose estimation.

Background: The American Association of Physicists in Medicine (AAPM) report 293 is more accurate than report 220 in evaluating the absorbed radiation dose during head computed tomography (CT) examination. We aimed to investigate the associations between age, head circumference (HC), the conversion factor (f293), and specific-size dose estimation (SSDE293) during these procedures. The rapid radiation dose was also estimated based on the AAPM report 293. Methods: In this retrospective, cross-sectional study, unenhanced CT images of the head were retrospectively collected from 1,222 participants from Union Hospital and Hubei Cancer Hospital between December 2018 and September 2019. Scan parameters, including age, HC, water-equivalent diameter (DW), and volumetric computed tomography dose index (CTDIvol), were generated automatically using indigenously-developed image processing software. The corresponding f293 and SSDE293 were calculated according to the AAPM report 293. The analyses were performed using linear regression. Results: In the younger group, age and HC were significantly negatively correlated with SSDE293 (r=-0.33 and -0.44, respectively; both P values ≤0.001). No significant correlation was reported between age, HC, and SSDE293 in the older group. Moreover, age was significantly negatively associated with f293 in the younger and older groups (r=-0.80 and -0.13, respectively; both P values ≤0.001). A significantly negative association was seen between f293 and increased HC in both age groups (r=-0.92 and -0.82, respectively; both P values ≤0.001). Conclusions: The HC of patients was associated with head conversion. HC is a feasible indicator for rapidly estimating the radiation dose in head CT examinations based on the AAPM report 293.

A rare presentation of POEMS syndrome on magnetic resonance neurography: a case series.

Polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, skin changes (POEMS) syndrome is a multisystem disease associated with underlying plasma cell neoplasm. Here, we present two cases of POEMS syndrome that manifested on magnetic resonance neurography as an increasing bone mass with cortical disruption, direct invading nerve roots and lumbar gluteal muscles. These features have not been previously reported. We also report a case with diffuse hypertrophy and enhancement of the brachial and lumbosacral plexus, which mimics the most common chronic inflammatory demyelinating polyradiculoneuropathy. Moreover, we detected perineurium effusions in the plexus, coupled with a variety of myofascitis and atrophy in denervated muscle. The case series is of concern to atypical magnetic resonance imaging findings of POEMS syndrome in the bone and peripheral nerve system as critical attacked target organs, which would be facilitating diagnosis.

Infiltration of the spinal cord and peripheral nerves in multiple myeloma.

Background: Multiple myeloma (MM) is a hematological malignancy, and intramedullary spinal cord metastasis is extremely rare. Methods: Clinical and radiological data were collected from electronic medical records as well as a literature review of reported cases. Results: We report a rare case of IgA-LAM stage IIB MM with involvement of the spinal cord and peripheral nervous system. Laboratory studies showed elevated levels of serum ß2-macroglobulin and cerebrospinal fluid protein. Electromyography revealed a demyelinating process with motor conduction blocks. On MRI, the lesions of MM bone marrow are characterized as a type of diffuse infiltration. MR neurography demonstrated an enhanced nodule in the thoracic segment with swelling of the cervicothoracic segments of the spinal cord. Moreover, swelling and hypertrophy of the entire nerve branchial, lumbosacral plexus, and cauda equina were detected, accompanied by myofascitis and denervated muscles. Ultimately, the condition of the patient deteriorated quickly and she died with a diagnosis of refractory MM. Conclusion: MRI not only has the advantage of displaying the primary involved site of the bone marrow but also facilitates detecting extramedullary hematopoietic MM, such as infiltrating sites of the central and/or peripheral nervous system.