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1. Simultaneous Mapping of T1 and T2 Using Cardiac Magnetic Resonance Fingerprinting in a Cohort of Healthy Subjects at 1. 5T

   https://doi.org/10.1002/jmri.27155  

   Hamilton, Jesse I. ; Pahwa, Shivani ; Adedigba, Joseph ; Frankel, Samuel ; O'Connor, Gregory ; Thomas, Rahul ; Walker, Jonathan R. ; Killinc, Ozden ; Lo, Wei‐Ching ; Batesole, Joshua ; et al ( March 2020 , Journal of Magnetic Resonance Imaging)

   Cardiac MR fingerprinting (cMRF) is a novel technique for simultaneous T₁and T₂mapping.

   To compare T₁/T₂measurements, repeatability, and map quality between cMRF and standard mapping techniques in healthy subjects.

   Prospective.

   In all, 58 subjects (ages 18–60).

   cMRF, modified Look–Locker inversion recovery (MOLLI), and T₂‐prepared balanced steady‐state free precession (bSSFP) at 1.5T.

   T₁/T₂values were measured in 16 myocardial segments at apical, medial, and basal slice positions. Test–retest and intrareader repeatability were assessed for the medial slice. cMRF and conventional mapping sequences were compared using ordinal and two alternative forced choice (2AFC) ratings.

   Pairedt‐tests, Bland–Altman analyses, intraclass correlation coefficient (ICC), linear regression, one‐way analysis of variance (ANOVA), and binomial tests.

   Average T₁measurements were: basal 1007.4±96.5 msec (cMRF), 990.0±45.3 msec (MOLLI); medial 995.0±101.7 msec (cMRF), 995.6±59.7 msec (MOLLI); apical 1006.6±111.2 msec (cMRF); and 981.6±87.6 msec (MOLLI). Average T₂measurements were: basal 40.9±7.0 msec (cMRF), 46.1±3.5 msec (bSSFP); medial 41.0±6.4 msec (cMRF), 47.4±4.1 msec (bSSFP); apical 43.5±6.7 msec (cMRF), 48.0±4.0 msec (bSSFP). A statistically significant bias (cMRF T₁larger than MOLLI T₁) was observed in basal (17.4 msec) and apical (25.0 msec) slices. For T₂, a statistically significant bias (cMRF lower than bSSFP) was observed for basal (–5.2 msec), medial (–6.3 msec), and apical (–4.5 msec) slices. Precision was lower for cMRF—the average of the standard deviation measured within each slice was 102 msec for cMRF vs. 61 msec for MOLLI T₁, and 6.4 msec for cMRF vs. 4.0 msec for bSSFP T₂. cMRF and conventional techniques had similar test–retest repeatability as quantified by ICC (0.87 cMRF vs. 0.84 MOLLI for T₁; 0.85 cMRF vs. 0.85 bSSFP for T₂). In the ordinal image quality comparison, cMRF maps scored higher than conventional sequences for both T₁(all five features) and T₂(four features).

   This work reports on myocardial T₁/T₂measurements in healthy subjects using cMRF and standard mapping sequences. cMRF had slightly lower precision, similar test–retest and intrareader repeatability, and higher scores for map quality.

   2

   Stage 1 J. Magn. Reson. Imaging 2020;52:1044–1052.

    

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2. Assessment of Complex Flow Patterns in Patients With Carotid Webs, Patients With Carotid Atherosclerosis, and Healthy Subjects Using 4D Flow MRI

   https://doi.org/10.1002/jmri.29013  

   El Sayed, Retta ; Park, Charlie C. ; Shah, Zahraw ; Nahab, Fadi B. ; Haussen, Diogo C. ; Allen, Jason W. ; Oshinski, John N. ( September 2023 , Journal of Magnetic Resonance Imaging)

   Carotid webs (CaWs) are fibromuscular projections in the internal carotid artery (ICA) that cause mild luminal narrowing (<50%), but may be causative in up to one‐third of seemingly cryptogenic strokes. Understanding hemodynamic alterations caused by CaWs is imperative to assessing stroke risk. Time‐Average Wall Shear Stress (TAWSS) and Oscillatory Shear Index (OSI) are hemodynamic parameters linked to vascular dysfunction and thrombosis.

   To test the hypothesis: “CaWs are associated with lower TAWSS and higher OSI than mild atherosclerosis or healthy carotid bifurcation.”

   Prospective study.

   A total of 35 subjects (N = 14 bifurcations with CaW, 11F, age: 49 ± 10, 10 mild atherosclerosis 6F, age: 72 ± 9, 11 healthy 9F, age: 42 ± 13).

   4D flow/STAR‐MATCH/3D TOF/3T MRI, CTA.

   4D Flow velocity data were analyzed in two ways: 1) 3D ROI in the ICA bulbar segment (complex flow patterns are expected) was used to quantify the regions with low TAWSS and high OSI. 2) 2D planes were placed perpendicular to the centerline of the carotid bifurcation for detailed analysis of TAWSS and OSI.

   Independent‐samples Kruskal–Wallis‐H test with 0.05 used for statistical significance.

   The percent surface area where low TAWSS was present in the ICA bulb was 12.3 ± 8.0% (95% CI: 7.6–16.9) in CaW subjects, 1.6 ± 1.9% (95% CI: 0.2–2.9) in atherosclerosis, and 8.5 ± 7.7% (95% CI: 3.6–13.4) in healthy subjects, all differences were statistically significant (ƞ² = 0.3 [95% CI: 0.05–0.5],P‐value CaW vs. healthy = 0.2). OSI had similar values in the CCA between groups (ƞ² = 0.07 [95% CI: 0.0–0.2],P‐value = 0.5), but OSI was significantly higher downstream of the bifurcation in CaW subjects compared to atherosclerosis and normal subjects. OSI returned to similar values between groups 1.5 diameters distal to the bifurcation (ƞ² = 0.03 [95% CI: 0.0–0.2],P‐value = 0.7).

   Lower TAWSS and higher OSI are present in the ICA bulb in patients with CaW when compared to patients with atherosclerotic or healthy subjects.

   2

   Stage 2

    

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3. Computational fluid dynamic analysis of aggressive turbinate reductions: is it a culprit of empty nose syndrome?

   https://doi.org/10.1002/alr.22350  

   Malik, Jennifer ; Li, Chengyu ; Maza, Guillermo ; Farag, Alexander A. ; Krebs, Jillian P. ; McGhee, Sam ; Zappitelli, Gabriela ; Deshpande, Bhakthi ; Otto, Bradley A. ; Zhao, Kai ( May 2019 , International Forum of Allergy & Rhinology)

   Empty nose syndrome (ENS) remains highly controversial, with aggressive inferior turbinate reduction (ITR) or mucociliary dysfunction frequently implicated. However, the appropriate degree of ITR is highly debatable.

   We applied individual computed tomography (CT)‐based computational fluid dynamics (CFD) to 5 patients receiving relatively aggressive ITR but with no ENS symptoms, and compared them to 27 symptomatic ENS patients who all had histories of aggressive ITRs, and 42 healthy controls. Patients’ surgical outcomes were confirmed with 22‐item Sino‐Nasal Outcome Test (SNOT‐22) (ITR: 6.40 ± 4.56; ENS: 58.2 ± 15.9; healthy: 13.2 ± 14.9), Nasal Obstruction Symptom Evaluation (NOSE) scores (ITR: 4.00 ± 2.24; ENS: 69.4 ± 17.1; healthy: 11.9 ± 12.9), and Empty Nose Syndrome 6‐Item Questionnaire (ENS6Q) (≥11 for ENS).

   Both aggressive ITR without ENS symptoms and symptomatic ENS patients had significantly lower nasal resistance (ITR: 0.059 ± 0.020 Pa·s/mL; ENS: 0.052 ± 0.015 Pa·s/mL; healthy: 0.070 ± 0.021 Pa·s/mL) and higher cross‐sectional areas surrounding the inferior turbinate (ITR: 0.94 ± 0.21 cm²; ENS: 1.19 ± 1.05 cm²; healthy: 0.42 ± 0.22 cm²) than healthy controls. The lack of significant differences among patient groups indicated similar degrees of surgeries between ITR with and without ENS symptom cohorts. However, symptomatic ENS patients have paradoxical significantly less airflow in the inferior meatus (ITR: 47.7% ± 23.6%; ENS: 25.8% ± 17.6%; healthy: 36.5 ± 15.9%; bothp< 0.01), but higher airflow around the middle meatus (ITR: 49.7% ± 22.6%; ENS: 66.5% ± 18.3%; healthy: 49.9% ± 15.1%,p< 0.0001) than aggressive ITR without symptoms and controls. Aggressive ITR patients have increased inferior meatus airflow as expected (p< 0.05). This imbalanced airflow produced less inferior wall‐shear‐stress distribution among symptomatic ENS patients only (ITR: 42.45% ± 11.4%; ENS: 32.2% ± 12.6%; healthy: 49.7% ± 9.9%). ENS patients (n = 12) also had impaired nasal trigeminal function, as measured by menthol lateralization detection thresholds (ITR: 15.2 ± 1.2; ENS: 10.3 ± 3.9; healthy: 13.8 ± 3.09, bothp< 0.0001). Surprisingly, aggressive ITR patients without ENS symptoms have better menthol lateralization detection thresholds (LDTs) than healthy controls.

   Although turbinate tissue loss is linked with ENS, the degree of ITR that might distinguish postoperative patient satisfaction in their nasal breathing vs development of ENS symptoms is unclear. Our results suggest that a combination of distorted nasal aerodynamics and loss of mucosal sensory function may potentially lead to ENS symptomology.

    

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4. Generalizability of Deep Learning Segmentation Algorithms for Automated Assessment of Cartilage Morphology and MRI Relaxometry

   https://doi.org/10.1002/jmri.28365  

   Schmidt, Andrew M. ; Desai, Arjun D. ; Watkins, Lauren E. ; Crowder, Hollis A. ; Black, Marianne S. ; Mazzoli, Valentina ; Rubin, Elka B. ; Lu, Quin ; MacKay, James W. ; Boutin, Robert D. ; et al ( July 2022 , Journal of Magnetic Resonance Imaging)

   Deep learning (DL)‐based automatic segmentation models can expedite manual segmentation yet require resource‐intensive fine‐tuning before deployment on new datasets. The generalizability of DL methods to new datasets without fine‐tuning is not well characterized.

   Evaluate the generalizability of DL‐based models by deploying pretrained models on independent datasets varying by MR scanner, acquisition parameters, and subject population.

   Retrospective based on prospectively acquired data.

   Overall test dataset: 59 subjects (26 females); Study 1: 5 healthy subjects (zero females), Study 2: 8 healthy subjects (eight females), Study 3: 10 subjects with osteoarthritis (eight females), Study 4: 36 subjects with various knee pathology (10 females).

   A 3‐T, quantitative double‐echo steady state (qDESS).

   Four annotators manually segmented knee cartilage. Each reader segmented one of four qDESS datasets in the test dataset. Two DL models, one trained on qDESS data and another on Osteoarthritis Initiative (OAI)‐DESS data, were assessed. Manual and automatic segmentations were compared by quantifying variations in segmentation accuracy, volume, and T2 relaxation times for superficial and deep cartilage.

   Dice similarity coefficient (DSC) for segmentation accuracy. Lin's concordance correlation coefficient (CCC), Wilcoxon rank‐sum tests, root‐mean‐squared error‐coefficient‐of‐variation to quantify manual vs. automatic T2 and volume variations. Bland–Altman plots for manual vs. automatic T2 agreement. APvalue < 0.05 was considered statistically significant.

   DSCs for the qDESS‐trained model, 0.79–0.93, were higher than those for the OAI‐DESS‐trained model, 0.59–0.79. T2 and volume CCCs for the qDESS‐trained model, 0.75–0.98 and 0.47–0.95, were higher than respective CCCs for the OAI‐DESS‐trained model, 0.35–0.90 and 0.13–0.84. Bland–Altman 95% limits of agreement for superficial and deep cartilage T2 were lower for the qDESS‐trained model, ±2.4 msec and ±4.0 msec, than the OAI‐DESS‐trained model, ±4.4 msec and ±5.2 msec.

   The qDESS‐trained model may generalize well to independent qDESS datasets regardless of MR scanner, acquisition parameters, and subject population.

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   Stage 1

    

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5. Safety, feasibility, and efficacy of strengthening exercise in Duchenne muscular dystrophy

   https://doi.org/10.1002/mus.27137  

   Lott, Donovan J. ; Taivassalo, Tanja ; Cooke, Korey D. ; Park, Hyunjun ; Moslemi, Zahra ; Batra, Abhinandan ; Forbes, Sean C. ; Byrne, Barry J. ; Walter, Glenn A. ; Vandenborne, Krista ( December 2020 , Muscle & Nerve)

   This two‐part study explored the safety, feasibility, and efficacy of a mild–moderate resistance isometric leg exercise program in ambulatory boys with Duchenne muscular dystrophy (DMD).

   First, we used a dose escalation paradigm with varying intensity and frequency of leg isometric exercise to determine the dose response and safety in 10 boys. Second, we examined safety and feasibility of a 12‐wk in‐home, remotely supervised, mild–moderate intensity strengthening program in eight boys. Safety measures included T₂MRI, creatine kinase levels, and pain. Peak strength and function (time to ascend/descend four stairs) were also measured.

   Dose‐escalation revealed no signs of muscle damage. Seven of the eight boys completed the 12‐wk in‐home program with a compliance of 84.9%, no signs of muscle damage, and improvements in strength (knee extensorsP < .01; knee flexorsP < .05) and function (descending stepsP < .05).

   An in‐home, mild–moderate intensity leg exercise program is safe with potential to positively impact both strength and function in ambulatory boys with DMD.

    

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