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White matter plasticity in healthy older adults: The effects of aerobic exercise.
Mendez Colmenares, A, Voss, MW, Fanning, J, Salerno, EA, Gothe, NP, Thomas, ML, McAuley, E, Kramer, AF, Burzynska, AZ
NeuroImage. 2021;:118305
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Abstract
White matter deterioration is associated with cognitive impairment in healthy aging and Alzheimer's disease. It is critical to identify interventions that can slow down white matter deterioration. So far, clinical trials have failed to demonstrate the benefits of aerobic exercise on the adult white matter using diffusion Magnetic Resonance Imaging. Here, we report the effects of a 6-month aerobic walking and dance interventions (clinical trial NCT01472744) on white matter integrity in healthy older adults (n = 180, 60-79 years) measured by changes in the ratio of calibrated T1- to T2-weighted images (T1w/T2w). Specifically, the aerobic walking and social dance interventions resulted in positive changes in the T1w/T2w signal in late-myelinating regions, as compared to widespread decreases in the T1w/T2w signal in the active control. Notably, in the aerobic walking group, positive change in the T1w/T2w signal correlated with improved episodic memory performance. Lastly, intervention-induced increases in cardiorespiratory fitness did not correlate with change in the T1w/T2w signal. Together, our findings suggest that white matter regions that are vulnerable to aging retain some degree of plasticity that can be induced by aerobic exercise training. In addition, we provided evidence that the T1w/T2w signal may be a useful and broadly accessible measure for studying short-term within-person plasticity and deterioration in the adult human white matter.
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Comparison of 18F-FDG PET-MR and fecal biomarkers in the assessment of disease activity in patients with ulcerative colitis.
Li, Y, Khamou, M, Schaarschmidt, BM, Umutlu, L, Forsting, M, Demircioglu, A, Haubold, J, Koch, AK, Bruckmann, NM, Sawicki, LM, et al
The British journal of radiology. 2020;(1112):20200167
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Abstract
OBJECTIVE To compare the diagnostic performance of fecal biomarkers and 18F-fludeoxyglucose (18F-FDG) positron emmision tomography-MR (PET-MR) in the assessment of disease activity in patients with ulcerative colitis. METHODS This study was conducted under the framework of a single-center clinical trial (clinicaltrials.gov [NCT03781284]). N = 50 participants were enrolled. Fecal samples were collected before bowel preparation. All patients underwent whole-body 18F-FDG PET-MR followed by ileocolonoscopy within 24 h. Diagnostic performance of five fecal biomarkers (calprotectin, lactoferrin, polymorphonuclear leukocyte elastase, S100A12 and eosinophil-derived neurotoxin), MR morphological parameters (MRmorph), diffusion-weighted imaging and PET in detecting active disease determined by Rachmilewitz endoscopic activity index (EAI) were evaluated and compared with each other. Correlations between fecal biomarkers, PET and endoscopy were calculated. RESULTS According to EAI, n = 38 patients presented with endoscopically active disease (16 mild, 19 moderate and 3 severe). All five biomarkers, PET and MRmorph could differentiate endoscopically active disease from endoscopic remission without significant difference regarding their operating characteristics (accuracies between 0.673 for calprotectin and 0.898 for lactoferrin). In predicting endoscopically moderate to severe disease, PET showed the highest diagnostic performance (accuracy = 0.857) compared to calprotectin and lactoferrin (accuracy = 0.633 and 0.735). PET had also the strongest correlation with endoscopy (ρ = 0.685, p < 0.001), while within fecal biomarkers the levels of lactoferrin and eosinophil-derived neurotoxin correlated significantly with EAI (ρ = 0.423 and 0.528, both p < 0.05). CONCLUSION Both fecal biomarkers and PET-MR were excellent non-invasive diagnostic tools in the assessment of disease activity in ulcerative colitis. ADVANCES IN KNOWLEDGE Both fecal biomarkers and PET-MR parameters are able to predict endoscopically active disease with comparable diagnostic performance. PET had the highest correlation with endoscopy and outperformed fecal biomarkers in differentiating moderate to severe from mild disease.
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Differentiation of benign and malignant lymph nodes in pediatric patients on ferumoxytol-enhanced PET/MRI.
Muehe, AM, Siedek, F, Theruvath, AJ, Seekins, J, Spunt, SL, Pribnow, A, Hazard, FK, Liang, T, Daldrup-Link, H
Theranostics. 2020;(8):3612-3621
Abstract
The composition of lymph nodes in pediatric patients is different from that in adults. Most notably, normal lymph nodes in children contain less macrophages. Therefore, previously described biodistributions of iron oxide nanoparticles in benign and malignant lymph nodes of adult patients may not apply to children. The purpose of our study was to evaluate if the iron supplement ferumoxytol improves the differentiation of benign and malignant lymph nodes in pediatric cancer patients on 18F-FDG PET/MRI. Methods: We conducted a prospective clinical trial from May 2015 to December 2018 to investigate the value of ferumoxytol nanoparticles for staging of children with cancer with 18F-FDG PET/MRI. Ferumoxytol is an FDA-approved iron supplement for the treatment of anemia and has been used "off-label" as an MRI contrast agent in this study. Forty-two children (7-18 years, 29 male, 13 female) received a 18F-FDG PET/MRI at 2 (n=20) or 24 hours (h) (n=22) after intravenous injection of ferumoxytol (dose 5 mg Fe/kg). The morphology of benign and malignant lymph nodes on ferumoxytol-enhanced T2-FSE sequences at 2 and 24 h were compared using a linear regression analysis. In addition, ADCmean-values, SUV-ratio (SUVmax lesion/SUVmean liver) and R2*-relaxation rate of benign and malignant lymph nodes were compared with a Mann-Whitney-U test. The accuracy of different criteria was assessed with a receiver operating characteristics (ROC) curve. Follow-up imaging for at least 6 months served as the standard of reference. Results: We examined a total of 613 lymph nodes, of which 464 (75.7%) were benign and 149 (24.3%) were malignant. On ferumoxytol-enhanced T2-FSE images, benign lymph nodes showed a hypointense hilum and hyperintense parenchyma, while malignant lymph nodes showed no discernible hilum. This pattern was not significantly different at 2 h and 24 h postcontrast (p=0.82). Benign and malignant lymph nodes showed significantly different ferumoxytol enhancement patterns, ADCmean values of 1578 and 852 x10-6 mm2/s, mean SUV-ratios of 0.5 and 2.8, and mean R2*-relaxation rate of 127.8 and 84.4 Hertz (Hz), respectively (all p<0.001). The accuracy of ADCmean, SUV-ratio and pattern (area under the curve (AUC): 0.99; 0.98; 0.97, respectively) was not significantly different (p=0.07). Compared to these three parameters, the accuracy of R2* was significantly lower (AUC: 0.93; p=0.001). Conclusion: Lymph nodes in children show different ferumoxytol-enhancement patterns on MRI than previously reported for adult patients. We found high accuracy (>90%) of ADCmean, SUV-ratio, pattern, and R2* measurements for the characterization of benign and malignant lymph nodes in children. Ferumoxytol nanoparticle accumulation at the hilum can be used to diagnose a benign lymph node. In the future, the delivery of clinically applicable nanoparticles to the hilum of benign lymph nodes could be harnessed to deliver theranostic drugs for immune cell priming.
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Comparison of 99mTc-Sestamibi Molecular Breast Imaging and Breast MRI in Patients With Invasive Breast Cancer Receiving Neoadjuvant Chemotherapy.
Hunt, KN, Conners, AL, Goetz, MP, O'Connor, MK, Suman, V, Kalari, K, Weinshilboum, R, Wang, L, Carter, J, McLaughlin, S, et al
AJR. American journal of roentgenology. 2019;(4):932-943
Abstract
OBJECTIVE. The purpose of this study is to prospectively compare the size of invasive breast cancer before and after neoadjuvant chemotherapy (NAC) at breast MRI and molecular breast imaging (MBI) and to assess the accuracy of post-NAC MBI and MRI relative to pathologic analysis. SUBJECTS AND METHODS. Women with invasive breast cancer greater than or equal to 1.5 cm were enrolled to compare the longest dimension before and after NAC at MRI and MBI. MBI was performed on a dual-detector cadmium zinc telluride system after administration of 6.5 mCi (240 MBq) 99mTc-sestamibi. The accuracy of MRI and MBI in assessing residual disease (invasive disease or ductal carcinoma in situ) was determined relative to pathologic examination. RESULTS. The longest dimension at MRI was within 1.0 cm of that at MBI in 72.3% of cases before NAC and 70.1% of cases after NAC. The difference between the longest dimension at imaging after NAC and pathologic tumor size was within 1 cm for 58.7% of breast MRI cases and 59.6% of MBI cases. Ninety patients underwent both MRI and MBI after NAC. In the 56 patients with invasive residual disease, 10 (17.9%) cases were negative at MRI and 23 (41.1%) cases were negative at MBI. In the 34 patients with breast pathologic complete response, there was enhancement in 10 cases (29.4%) at MRI and uptake in six cases (17.6%) at MBI. Sensitivity, specificity, positive predictive value, and negative predictive value after NAC were 82.8%, 69.4%, 81.4%, and 71.4%, respectively, for MRI and 58.9%, 82.4%, 84.6%, and 54.9%, respectively, for MBI. CONCLUSION. Breast MRI and MBI showed similar disease extent before NAC. MBI may be an alternative to breast MRI in patients with a contraindication to breast MRI. Neither modality showed sufficient accuracy after NAC in predicting breast pathologic complete response to obviate tissue diagnosis to assess for residual invasive disease. Defining the extent of residual disease compared with pathologic evaluation was also limited after NAC for both breast MRI and MBI.
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Non-invasive assessment of portal hypertension by multi-parametric magnetic resonance imaging of the spleen: A proof of concept study.
Levick, C, Phillips-Hughes, J, Collier, J, Banerjee, R, Cobbold, JF, Wang, LM, Piechnik, SK, Robson, MD, Neubauer, S, Barnes, E, et al
PloS one. 2019;(8):e0221066
Abstract
BACKGROUND AND AIMS Non-invasive assessment of portal hypertension is an area of unmet need. This proof of concept study aimed to evaluate the diagnostic accuracy of a multi-parametric magnetic resonance technique in the assessment of portal hypertension. Comparison to other non-invasive technologies was a secondary aim. METHODS T1 and T2* maps through the liver and spleen were acquired prior to trans-jugular liver biopsy and hepatic vein pressure gradient (HVPG) measurement. T1 measurements reflect changes in tissue water content, but this relationship is confounded by the presence of iron, which in turn can be quantified accurately from T2* maps. Data were analysed using LiverMultiScan (Perspectum Diagnostics, Oxford, UK) which applies an algorithm to remove the confounding effect of iron, yielding the "iron corrected T1" (cT1). Sensitivity, specificity, diagnostic values and area under the curve were derived for spleen cT1, liver cT1, transient elastography, and serum fibrosis scores. HVPG was the reference standard. RESULTS Nineteen patients (15 men) with median age 57 years were included. Liver disease aetiologies included non-alcoholic fatty liver disease (n = 9; 47%) and viral hepatitis (n = 4; 21%). There was strong correlation between spleen cT1 and HVPG (r = 0.69; p = 0.001). Other non-invasive biomarkers did not correlate with HVPG. Spleen cT1 had excellent diagnostic accuracy for portal hypertension (HVPG >5 mmHg) and clinically significant portal hypertension (HVPG ≥10 mmHg) with an area under the receiver operating characteristic curve of 0.92 for both. CONCLUSION Spleen cT1 is a promising biomarker of portal pressure that outperforms other non-invasive scores and should be explored further.
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Does higher field strength translate into better diagnostic accuracy? A prospective comparison of breast MRI at 3 and 1.5 Tesla.
Dietzel, M, Wenkel, E, Hammon, M, Clauser, P, Uder, M, Schulz-Wendtland, R, Baltzer, PAT
European journal of radiology. 2019;:51-56
Abstract
OBJECTIVE We performed a prospective monocentric study to inter-individually compare the diagnostic accuracy of breast MRI at 1.5 T and 3 T. METHODS During a consecutive period of 12 months all 982 patients receiving breast MRI according to standard indications (problem solving, preoperative staging) were randomized to one 3 T or 1.5 T scanner both equipped with dedicated 16-channel breast coils. Protocols at 1.5 T and 3 T were optimized and in line with international recommendations. Due to restricted time slot availabilities, the randomization-key was defined as 1/10 (3 T/1.5 T). All examinations were read by two experts in breast MRI (>25 and 8 years of experience) who assigned a BI-RADS category per breast. Histopathological verification or long-term MRI follow-up (>24 months) served as standard of reference. Results were analyzed using cross tabulations, standard estimates of diagnostic accuracy, Chi-square test and Mann-Whitney U test (alpha = 5%). RESULTS 1961 breasts were included. 1746 (89%) were imaged at 1.5 T and 215 at 3 T (11%). The 1.5 T and 3 T study cohort did not show significant differences regarding patient age (P = 0.71), results of the reference standard (P = 0.09) and indication for MRI (P = 0.53). Overall Sensitivity (94.7%), Specificity (91.4%), Accuracy (91.9%) and Negative Predictive Value (99.0%) were within the range of the literature. Pairwise comparison of Sensitivity (1,5 T/3 T: 94.1/97.9%), Specificity (91.6/%89.3%), Accuracy (92.0%/91.2%) and Negative Predictive Value (98.9%/99.3%) were without significant differences (P = 0.29-0.74). CONCLUSION In this prospective monocentric study, we identified comparably high diagnostic accuracy for both 1.5 T and 3 T breast MRI. Both 1.5 T and 3 T are equally suited for breast imaging.
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Comparison of Contrast-Enhanced Mammography and Contrast-Enhanced Breast MR Imaging.
Lewin, J
Magnetic resonance imaging clinics of North America. 2018;(2):259-263
Abstract
Contrast-enhanced mammography (CEM) is a contrast-enhanced modality for breast cancer detection that utilizes iodinated contrast and dual-energy imaging performed on a digital mammography unit with only slight modifications. It is approved by the US Food and Drug Administration, commercially available, and in routine clinical use at centers around the world. It has similar sensitivity and specificity to MR Imaging and has advantages in terms of cost, patient acceptability, and examination time. MR Imaging has some advantages compared with CEM, especially in its ability to image the complete axilla and the chest wall.
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Indirect vs direct assessment of gastric emptying: A randomized crossover trial comparing C-isotope breath analysis and MRI.
Camps, G, Mars, M, Witteman, BJM, de Graaf, C, Smeets, PAM
Neurogastroenterology and motility. 2018;(7):e13317
Abstract
BACKGROUND Indirect methods to assess gastric emptying (GE), such as 13 C breath tests (BT), are commonly used. However, BT usually use a sampling time of 4+ hours. The current study aims to assess the validity of BT for four liquid meals differing in physicochemical properties. To this aim, we compared them to MRI GE-measurements. METHODS Fifteen healthy males (age 22.6 ± 2.4 years, BMI 22.6 ± 1.8 kg/m2 ) participated in a randomized 2 × 2 crossover experiment. Test foods were liquid meals, which were either thin/thick and 100/500 kcal, labeled with 100 mg of 13 C-octanoate. GE was measured with MRI and assessed by 13 C recovery from breath. Participants were scanned every 10 minutes and at six time points breath samples were collected up to t = 90 minutes. Two curves were fitted to the data to estimate emptying halftime (t50 Ghoos and t50 Bluck ). T50 times were ranked per participant and compared between methods. KEY RESULTS On average, MRI and BT showed similar t50 rankings for the four liquid meals. In comparison to MRI, t50 Ghoos overestimated, while t50 Bluck underestimated GE time. Moreover, more viscous foods were overestimated. In most participants individual t50 time rankings differed significantly between methods. CONCLUSIONS & INFERENCES BT can assess relative emptying differences on group level and collecting breath data for 90 minutes constitutes a lower burden for participants and the research facility. However, BT has severe shortcomings compared to MRI for individual GE assessment. Notably, food matrix effects should be considered when interpreting the results of BT.
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Comparison of the Timing of Hepatic Arterial Phase and Image Quality Using Test-Bolus and Bolus-Tracking Techniques in Gadolinium-Ethoxybenzyl-Diethylenetriamine Pentaacetic Acid-Enhanced Hepatic Dynamic Magnetic Resonance Imaging.
Iyama, Y, Nakaura, T, Yokoyama, K, Kidoh, M, Utsunomiya, D, Oda, S, Namimoto, T, Yamashita, Y
Journal of computer assisted tomography. 2017;(4):638-643
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Abstract
OBJECTIVES The aim of this study was to compare the image quality, the degree of artifacts and the percentage of timing of the optimal hepatic arterial phase (HAP) between test-bolus and bolus-tracking methods on gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI). METHODS In this prospective study, 60 patients who underwent 3-dimensional dynamic Gd-EOB-DTPA-enhanced hepatic 3-T MRI were enrolled in this study. We randomly assigned the 30 patients to the bolus-tracking method, and another 30 patients to the test-bolus method. Signal-to-noise ratios of the liver and spleen in HAP were compared in the 2 groups. Two radiologists independently assessed the ratio of optimal timing of HAP and the degree of ringing and motion artifacts of the 2 protocols. RESULTS The signal-to-noise ratios of the liver (24.0 [SD, 6.4] vs 20.4 [SD, 4.0]) and spleen (30.0 [SD, 13.3] vs 23.6 [SD, 9.9]) were significantly higher in the test-bolus protocol than in the bolus-tracking protocol. The ratio of optimal timing was also significantly higher with the test-bolus protocol than with the bolus-tracking protocol (76.7% vs 40.0%). The degree of ringing and motion artifacts of test-bolus protocol was significantly lower than that of the bolus-tracking protocol (P < 0.01). CONCLUSIONS The test-bolus protocol in dynamic 3-T MRI can yield better qualitative image quality and more optimal timing of HAP images, while reducing the degree of artifacts compared with the bolus-tracking protocol.
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Evaluation and comparison of 3D intervertebral disc localization and segmentation methods for 3D T2 MR data: A grand challenge.
Zheng, G, Chu, C, Belavý, DL, Ibragimov, B, Korez, R, Vrtovec, T, Hutt, H, Everson, R, Meakin, J, Andrade, IL, et al
Medical image analysis. 2017;:327-344
Abstract
The evaluation of changes in Intervertebral Discs (IVDs) with 3D Magnetic Resonance (MR) Imaging (MRI) can be of interest for many clinical applications. This paper presents the evaluation of both IVD localization and IVD segmentation methods submitted to the Automatic 3D MRI IVD Localization and Segmentation challenge, held at the 2015 International Conference on Medical Image Computing and Computer Assisted Intervention (MICCAI2015) with an on-site competition. With the construction of a manually annotated reference data set composed of 25 3D T2-weighted MR images acquired from two different studies and the establishment of a standard validation framework, quantitative evaluation was performed to compare the results of methods submitted to the challenge. Experimental results show that overall the best localization method achieves a mean localization distance of 0.8 mm and the best segmentation method achieves a mean Dice of 91.8%, a mean average absolute distance of 1.1 mm and a mean Hausdorff distance of 4.3 mm, respectively. The strengths and drawbacks of each method are discussed, which provides insights into the performance of different IVD localization and segmentation methods.