Background
Multiple quantitative magnetic resonance imaging (MRI) methods have been described to noninvasively detect and characterize liver fibrosis, including diffusion-weighted imaging (DWI).
...Purpose
To evaluate associations between liver MRI DWI apparent diffusion coefficient (ADC) values and clinical factors and other quantitative liver MRI metrics in pediatric patients with autoimmune liver disease (AILD).
Materials and methods
Fifty-seven research liver MRI examinations performed from January 2017 to August 2018 for pediatric AILD registry participants were evaluated. Liver DWI ADC values, liver and spleen stiffness (kPa), and iron-corrected T1 (cT1; Perspectum Diagnostics) were measured at four anatomic levels. Participant age, sex, and laboratory data (alanine aminotransferase ALT, total bilirubin, alkaline phosphatase, gamma-glutamyl transferase GGT) were recorded. Spearman’s rank-order correlation (rho) and multiple linear regression were used to evaluate the associations between liver ADC values and predictor variables.
Results
Mean (SD) participant age was 14.8 (4.0) years, 45.6% (26/57) were girls. Mean liver DWI ADC value was 1.34 (0.14 × 10
−3
) mm
2
/s. Liver ADC values showed weak to moderate correlations with liver stiffness (
r
= − 0.42,
p
= 0.001), spleen stiffness (
r
= − 0.34;
p
= 0.015), whole-liver mean cT1 (
r
= − 0.39;
p
= 0.007), ALT (
r
= − 0.50;
p
= 0.0001), and GGT (
r
= − 0.48;
p
= 0.0004). Multiple linear regression showed liver stiffness (
p
= 0.0009) and sex (
p
= 0.023) to be independent predictors of liver ADC values.
Conclusion
Liver DWI ADC values are significantly associated with liver and spleen stiffnesses, liver cT1, ALT, GGT, and participant sex, with liver stiffness and sex remaining significant at multivariable regression. Liver ADC ultimately may play a role in multi-parametric prediction of chronic liver disease/fibrosis severity.
Objective/Hypothesis
To assess the ability of ultra‐short echo time (UTE)‐MRI to detect subglottic stenosis (SGS) and evaluate response to balloon dilation. To correlate measurements from UTE‐MRI ...with endotracheal‐tube (ETT)‐sizing and to investigate whether SGS causes change in airway dynamics.
Study Design
Animal research study.
Methods
Eight adult New‐Zealand white rabbits were used as they approximate neonatal airway‐size. The airways were measured using ETT‐sizing and 3D UTE‐MRI at baseline, 2 weeks post‐cauterization induced SGS injury, and post‐balloon dilation treatment. UTE‐MR images were acquired to determine airway anatomy and motion. Airways were segmented from MR images. Cross‐sectional area (CSA), major and minor diameters (Dmajor and Dminor), and eccentricity were measured.
Results
Post‐injury CSA at SGS was significantly reduced (mean 38%) compared to baseline (P = .003) using UTE‐MRI. ETT‐sizing correlated significantly with MRI‐measured CSA at the SGS location (r = 0.6; P < .01), particularly at the post‐injury timepoint (r = 0.93; P < .01). Outer diameter from ETT‐sizing (OD) correlated significantly with Dmajor (r = 0.63; P < .01) from UTE‐MRI at the SGS location, especially for the post‐injury timepoint (r = 0.91; P < .01). Mean CSA of upper trachea did not change significantly between end‐expiration and end‐inspiration at any timepoint (all P > .05). Eccentricity of the upper trachea increased significantly post‐balloon dilation (P < .05).
Conclusions
UTE‐MRI successfully detected SGS and treatment response in the rabbit model, with good correlation to ETT‐sizing. Balloon dilation increased CSA at SGS, but not to baseline values. SGS did not alter dynamic motion for the trachea in this rabbit model; however, tracheas were significantly eccentric post‐balloon dilation. UTE‐MRI can detect SGS without sedation or ionizing radiation and may be a non‐invasive alternative to ETT‐sizing.
Level of Evidence
NA Laryngoscope, 131:E1971–E1979, 2021
Inclusion of ethnic/racial minorities in clinical trials is essential to fully assess therapeutic efficacy. It is well-known that populations respond dissimilarly to interventions. Our objective is ...to analyze the inclusion of minority men in clinical trials for erectile dysfunction (ED).
We searched ClinicalTrials.gov for the disease keyword: “Erectile Dysfunction” and used “Prostate Cancer” for comparison. Completed trials which reported demographic data were included for analysis. Literature was reviewed to determine the prevalence of ED and prostate cancer (PC) among Hispanic, Black, White, and Asian men. The proportion of individuals of each group that participated in trials is divided by the proportion of each group in the disease population to calculate the “Participation to Prevalence Ratio” (PPR). PPRs between 0.8 and 1.2 indicates adequate representation, <0.8 is under-representation and >1.2 is over-representation.
A total of 312 trials were assessed: 289 for prostate cancer and 23 for ED. Hispanic men comprised 11.8% of ED trial participants and 4.6% of prostate cancer trial participants, yet represented 18% of ED patients and 7.3% of PC patients. Black/African-American (AA) men accounted for 10.2% of ED trial participants and 9.4% of PC trial participants, but comprise 16% of ED patients, and 16.3% of PC patients. Hispanic and AA men are under-represented in trials for ED and Prostate Cancer (Hispanic ED PPR = 0.66; Hispanic PC PPR = 0.63; AA ED PPR = 0.64; AA PC PPR = 0.58).
Our analysis shows that both Hispanic and AA men are underrepresented in both ED and PC clinical trials.
Background
Little is known about the relationships between MRI splenic T1 relaxation measurements and other radiologic and clinical markers of chronic liver disease, including the presence of ...radiologic portal hypertension.
Objective
To evaluate the relationships between MRI splenic T1 relaxation and other radiologic and clinical biomarkers of liver fibrosis, including the presence of radiologic portal hypertension, in children and young adults with autoimmune liver diseases (AILD).
Materials and Methods
Research MRI examinations performed at 1.5 T from 63 AILD registry participants were identified. Spleen T1 and iron-corrected T1 (cT1) relaxation measurements, liver cT1, liver/spleen stiffness, splenic length percentile for age, and presence of radiologic portal hypertension were recorded, along with demographic and laboratory data. The Mann–Whitney
U
test was used to compare continuous data between groups; Spearman correlation was used to evaluate associations. Areas-under-the-receiver operating characteristic curve (AuROC) was used to assess diagnostic performance.
Results
Mean age was 15.2 ± 4.1 years. Mean splenic T1 and cT1 values for the study population were 1158.0 ± 70.9 ms and 1436.0 ± 68.9 ms, respectively. Splenic T1 and cT1 values positively correlated with APRI and FIBROSIS-4 scores, splenic length percentile, liver cT1 values, and liver and spleen stiffnesses (
p
-values < 0.05). There was no significant relationship between splenic T1/cT1 and age (
p
-values > 0.05). Splenic T1 and cT1 values were higher in participants with vs. without radiologic portal hypertension (
n
= 18) (1213.4 ± 69.6 vs. 1135.4 ± 58.5 ms;
p
= 0.0001, and 1488.2 ± 64.8 vs. 1415.1 ± 59.1 ms;
p
= 0.0002). Splenic T1 and cT1 both demonstrated an AuROC of 0.81 for discriminating patients without and with portal hypertension (
p
-values < 0.0001).
Conclusion
Splenic T1 relaxation is associated with other radiologic and clinical biomarkers of liver fibrosis, including radiologic portal hypertension, in children and young adults with AILD.
Purpose
To compare automated versus standard of care manual processing of 2D gradient recalled echo (GRE) liver MR Elastography (MRE) in children and young adults.
Materials and methods
2D GRE liver ...MRE data from research liver MRI examinations performed as part of an autoimmune liver disease registry between March 2017 and March 2020 were analyzed retrospectively. All liver MRE data were acquired at 1.5 T with 60 Hz mechanical vibration frequency. For manual processing, two independent readers (R1, R2) traced regions of interest on scanner generated shear stiffness maps. Automated processing was performed using MREplus+ (Resoundant Inc.) using 90% (A90) and 95% (A95) confidence masks. Agreement was evaluated using intra-class correlation coefficients (ICC) and Bland–Altman analyses. Classification performance was evaluated using receiver operating characteristic curve (ROC) analyses.
Results
In 65 patients with mean age of 15.5 ± 3.8 years (range 8–23 years; 35 males) median liver shear stiffness was 2.99 kPa (mean 3.55 ± 1.69 kPa). Inter-reader agreement for manual processing was very strong (ICC = 0.99, mean bias = 0.01 kPa 95% limits of agreement (LoA): − 0.41 to 0.44 kPa). Correlation between manual and A95 automated processing was very strong (R1: ICC = 0.988, mean bias = 0.13 kPa 95% LoA: − 0.40 to 0.68 kPa; R2: ICC = 0.987, mean bias = 0.13 kPa 95% LoA: − 0.44 to 0.69 kPa). Automated measurements were perfectly replicable (ICC = 1.0; mean bias = 0 kPa).
Conclusion
Liver shear stiffness values obtained using automated processing showed excellent agreement with manual processing. Automated processing of liver MRE was perfectly replicable.
Renal fibrosis is an important marker in the progression of chronic kidney disease, and renal biopsy is the current reference standard for detecting its presence. Currently, non-invasive methods have ...only been partially successful in detecting renal fibrosis. Magnetization transfer imaging (MTI) allows estimates of renal fibrosis but may vary with scanning conditions. We hypothesized that MTI-derived renal fibrosis would be reproducible at 1.5T and 3T MRI and over time in fibrotic kidneys. Fifteen pigs with unilateral renal artery stenosis (RAS, n = 9) or age-matched sham controls (n = 6) underwent MTI-MRI at both 1.5T and 3T 6 weeks post-surgery and again 4 weeks later. Magnetization transfer ratio (MTR) measurements of fibrosis in both kidneys were compared between 1.5T and 3T, and the reproducibility of MTI at the two timepoints was evaluated at 1.5T and 3T. MTR at 3T with 600 Hz offset frequency successfully distinguished between normal, stenotic, and contralateral kidneys. There was excellent reproducibility of MTI at 1.5T and 3T over the two timepoints and no significant differences between MTR measurements at 1.5T and 3T. Therefore, MTI is a highly reproducible technique which is sensitive to detect changes in fibrotic compared to normal kidneys in the RAS porcine model at 3T.
Increased human life expectancy, due in part to improvements in infant and childhood survival, more active lifestyles, in combination with higher patient expectations for better health outcomes, is ...leading to an extensive change in the number, type and manner in which health conditions are treated. Over the next decades as the global population rapidly progresses toward a super‐aging society, meeting the long‐term quality of care needs is forecast to present a major healthcare challenge. The goal is to ensure longer periods of good health, a sustained sense of well‐being, with extended periods of activity, social engagement, and productivity. To accomplish these goals, multifunctionalized interfaces are an indispensable component of next generation medical technologies. The development of more sophisticated materials and devices as well as an improved understanding of human disease is forecast to revolutionize the diagnosis and treatment of conditions ranging from osteoarthritis to Alzheimer's disease and will impact disease prevention. This review examines emerging cutting‐edge bionic materials, devices and technologies developed to advance disease prevention, and medical care and treatment in our elderly population including developments in smart bandages, cochlear implants, and the increasing role of artificial intelligence and nanorobotics in medicine.
. Thoracoabdominal MRI is limited by respiratory motion, especially in populations who cannot perform breath-holds. One approach for reducing motion blurring in radially-acquired MRI is respiratory ...gating. Straightforward 'hard-gating' uses only data from a specified respiratory window and suffers from reduced SNR. Proposed 'soft-gating' reconstructions may improve scan efficiency but reduce motion correction by incorporating data with nonzero weight acquired outside the specified window. However, previous studies report conflicting benefits, and importantly the choice of soft-gated weighting algorithm and effect on image quality has not previously been explored. The purpose of this study is to map how variable soft-gated weighting functions and parameters affect signal and motion blurring in respiratory-gated reconstructions of radial lung MRI, using neonates as a model population.
. Ten neonatal inpatients with respiratory abnormalities were imaged using a 1.5 T neonatal-sized scanner and 3D radial ultrashort echo-time (UTE) sequence. Images were reconstructed using ungated, hard-gated, and several soft-gating weighting algorithms (exponential, sigmoid, inverse, and linear weighting decay outside the period of interest), with %N
representing the relative amount of data included. The apparent SNR (aSNR) and motion blurring (measured by the maximum derivative of image intensity at the diaphragm, MDD) were compared between reconstructions.
. Soft-gating functions produced higher aSNR and lower MDD than hard-gated images using equivalent %N
, as expected. aSNR was not identical between different gating schemes for given %N
. While aSNR was approximately linear with %N
for each algorithm, MDD performance diverged between functions as %N
decreased. Algorithm performance was relatively consistent between subjects, except in images with high noise.
. The algorithm selection for soft-gating has a notable effect on image quality of respiratory-gated MRI; the timing of included data across the respiratory phase, and not simply the amount of data, plays an important role in aSNR. The specific soft-gating function and parameters should be considered for a given imaging application's requirements of signal and sharpness.
Stiffness plays an important role in diagnosing renal fibrosis. However, kidney stiffness is altered by perfusion changes in many kidney diseases. Therefore, the aim of the current study is to ...determine the correlation of kidney stiffness with water intake. We hypothesize that kidney stiffness will increase with 1 L of water intake due to increased water perfusion to the kidneys. Additionally, stiffness of the kidneys will correlate with apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values before and after water intake. A 3 T MRI scanner was used to perform magnetic resonance elastography and diffusion tensor imaging of the kidneys on 24 healthy subjects (age range: 22‐66 years) before and after water intake of 1 L. A 3D T1‐weighted bladder scan was also performed to measure bladder volume before and after water intake. A paired t‐test was performed to evaluate the effect of water intake on the stiffness of kidneys, in addition to bladder volume. A Spearman correlation test was performed to determine the association between stiffness, bladder volume, ADC and FA values of both kidneys before and after water intake. The results show a significant increase in stiffness in different regions of the kidney (ie, percentage increase ranged from 3.6% to 7.5%) and bladder volume after water intake (all P < 0.05). A moderate significant negative correlation was observed between change in kidney stiffness and bladder volume (concordance correlation coefficient = ‐0.468, P < 0.05). No significant correlation was observed between stiffness and ADC or FA values before and after water intake in both kidneys (P > 0.05). Water intake caused a significant increase in the stiffness of the kidneys. The negative correlation between the change in kidney stiffness and bladder volume, before and after water intake, indicates higher perfusion pressure in the kidneys, leading to increased stiffness.
Stiffness plays an important role in diagnosing renal fibrosis. However, it is established that perfusion is altered in different kidney diseases, leading to changes in kidney stiffness. This study demonstrated that water intake caused significant increase in the stiffness of the kidneys. Also, negative correlation between changes in kidney stiffness and bladder volume before and after water intake indicates higher perfusion pressure in the kidneys, leading to increased stiffness.
PDF
