Current methods for estimation of proton density fat fraction (PDFF) of the liver using magnitude magnetic resonance (MR) imaging face the challenge of correctly estimating it when fat is the dominant molecule; i.e., PDFF is more than 50&#x25;. Therefore, the accuracy of the methods is limited to half-range operation. We introduce a method based on neural networks for regression capable of estimating over the full range of fat fractions. We built a neural network based on the angles and distances between the data in the discrete MR signal (ADALIFE), using these as features associated with different PDFFs and as input for the network. Tests were performed using ADALIFE and Multi-interference, a state-of-the-art method to estimate PDFFs, with simulated signals at various signal-to-noise (SNR) values. Results were compared in order to verify repeatability and agreement using Bland-Altman and REC curves. Results for Multi-interference were similar to its in vivo literature, showing the relevance of a simulation. ADALIFE was able to correctly estimate fat fractions up to 100&#x25;, breaking the current paradigm for full-range estimation using only offline postprocessing. Within half range, our method outperformed Multi-interference in repeatability and agreement, with narrower limits of agreement and lower expected error at any SNR.

Yuri A. Costa

Carlos P. Filho

Gabriela A. Flores

Evandro L. L. Rodrigues

Fernando F. Paiva

Full-Range Liver Fat Fraction Estimation in Magnitude MRI Using a Signal Shape Descriptor

Shape analysis provides a unique insight into biological processes. This paper evaluates the properties, performance, and utility of elliptical Fourier (eFourier) analysis to operationalise global shape, focussing on the human corpus callosum. 8000 simulated corpus callosum contours were generated, systematically varying in terms of global shape (midbody arch, splenium size), local complexity (surface smoothness), and nonshape characteristics (e.g., rotation). 2088 real corpus callosum contours were manually traced from the PATH study. Performance of eFourier was benchmarked in terms of its capacity to capture and then reconstruct shape and systematically operationalise that shape via principal components analysis. We also compared the predictive performance of corpus callosum volume, position in Procrustes-aligned Landmark tangent space, and position in eFourier n-dimensional shape space in relation to the Symbol Digit Modalities Test. Jaccard index for original vs. reconstructed from eFourier shapes was excellent (<i>M</i>=0.98). The combination of eFourier and PCA performed particularly well in reconstructing known n-dimensional shape space but was disrupted by the inclusion of local shape manipulations. For the case study, volume, eFourier, and landmark measures were all correlated. Mixed effect model results indicated all methods detected similar features, but eFourier estimates were most predictive, and of the two shape operationalization techniques had the least error and better model fit. Elliptical Fourier analysis, particularly in combination with principal component analysis, is a powerful, assumption-free and intuitive method of quantifying global shape of the corpus callosum and shows great promise for shape analysis in neuroimaging more broadly.

Erin I. Walsh

Marnie E. Shaw

Daniela A. Espinoza Oyarce

Mark Fraser

Nicolas Cherbuin

Assumption-Free Assessment of Corpus Callosum Shape: Benchmarking and Application

<i>Purpose.</i> Many patients with metallic implants are aware of the potential dangers in an MRI environment. Some implants cause sensations perceptible by the patient during an MRI scan. We wanted to find out if patients having an implant abort MRI scans more often than patients without implants. Furthermore, we wanted to know if the number of implants of a patient has an influence on the number of aborted MRI scans. As we use 3T MRI scanners from different manufacturers we wanted to see the influence of the “ScanWise” software option where scan parameters are adapted automatically to the maximal allowed limits of implant values. This publication should help to reduce possible anxiety in patients with implants.<i> Materials and Methods.</i> From May <svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-0.2064009pt" id="M1" height="12.3641pt" version="1.1" viewBox="-0.0498162 -12.1577 20.989 12.3641" width="20.989pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><path id="g113-50" d="M384 0V27C293 34 287 42 287 114V635C232 613 172 594 109 583V559L157 557C201 555 205 550 205 499V114C205 42 199 34 109 27V0H384Z"/></g><g transform="matrix(.013,0,0,-0.013,6.24,0)"><path id="g113-54" d="M153 550H386L412 615L406 623H120L82 318C104 327 142 338 184 338C294 338 347 275 347 187C347 112 305 39 221 39C160 39 119 71 97 89C88 97 80 96 71 90C59 80 50 67 49 57C48 45 52 36 66 23C80 9 123 -12 169 -12C221 -11 288 15 342 59C403 109 431 165 431 225C431 308 366 395 238 395C212 395 165 379 127 364L153 550Z"/></g><g transform="matrix(.0091,0,0,-0.0091,12.527,-5.741)"><path id="g58-114" d="M303 37L293 66C280 59 256 49 231 49S173 63 173 143V396H281C294 404 298 428 287 439H173V575L158 577L92 509V439H46L17 408L22 396H92V107C92 27 128 -12 192 -12C203 -12 218 -9 237 2L303 37Z"/></g><g transform="matrix(.0091,0,0,-0.0091,15.412,-5.741)"><path id="g58-102" d="M522 0V30C462 35 455 41 455 106V280C455 397 397 451 314 451C262 451 206 414 171 379V710C131 698 69 682 20 675V647C87 642 90 637 90 574V106C90 41 80 35 20 30V0H236V30C176 35 171 43 171 106V339C198 371 237 391 276 391C341 391 374 350 374 269V106C374 43 367 35 308 30V0H522Z"/></g></svg> 2017 until July <svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-0.2064009pt" id="M2" height="12.3641pt" version="1.1" viewBox="-0.0498162 -12.1577 20.989 12.3641" width="20.989pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><use xlink:href="#g113-50"/></g><g transform="matrix(.013,0,0,-0.013,6.24,0)"><path id="g113-56" d="M447 623H65C61 580 56 530 47 475H76C100 541 106 550 172 550H388C308 376 196 170 91 -1L98 -12L172 -2C268 204 360 408 455 611L447 623Z"/></g><g transform="matrix(.0091,0,0,-0.0091,12.527,-5.741)"><use xlink:href="#g58-114"/></g><g transform="matrix(.0091,0,0,-0.0091,15.412,-5.741)"><use xlink:href="#g58-102"/></g></svg> 2018 the implant type of patients was recorded. We looked how often aborted MRI scans coincided with the occurrence of implants and the MRI scanner type used.<i> Results.</i> 4088 examinations were collected for the analysis. No influence of implants on aborted MRI scans was registered. No influence of the number of implants on aborted MRI scans was registered. No influence of the use of “ScanWise” software on aborted MRI scans was registered when different scanners were compared.<i> Conclusion.</i> “MR Safe” or “MR Conditional” labelled implants did not have an impact on the MRI examinations. “ScanWise” software does not affect how MRI examinations are tolerated.

J. Steinbacher

M. R. McCoy

F. Klausner

W. Wallner

A. Oellerer

L. Machegger

Do Patients with Implants Experience Strong Sensations That Lead to Early Termination of MRI Examinations?

The present work compares intravenous (IV) and subcutaneous (SC) routes for contrast-enhanced MRI (CE-MRI) in mice. For that purpose, we selected two contrast media used in clinical practice. MRI acquisitions were performed at 1.5 T on five adult mice (Swiss, 41&#x2009;g +/- 3&#x2009;g). On each animal, four acquisitions were achieved with IV and SC administration of either Gd-DOTA or MS-325 (1 acquisition per week). For each route, 0.1&#x2009;mL of NaCl and 0.1&#x2009;mL of contrast agent were injected. For each acquisition, 200 T1-weighted images were acquired in a 2&#x2009;h 34&#x2009;min time lapse. For each route and contrast medium, dynamic contrast enhancement (DCE) curves were obtained. Time-to-peak (TTP), uptake, and washout constant-time values and contrast-to-noise ratio (CNR) were extracted. IV route TTP value was 4.9&#x2009;min with Gd-DOTA and 5.4&#x2009;min with MS-325. SC route TTP was 43.3&#x2009;min with Gd-DOTA and 45.0&#x2009;min with MS-325. Despite slower uptake constant-time, we show that SC is a potentially valuable alternative to the IV route in mouse preclinical CE-MRI.

Jean-Philippe Dillenseger

Christian Goetz

Amira Sayeh

Pierre-Emmanuel Zorn

St&#xe9;phane Kremer

Yves R&#xe9;mond

Andr&#xe9; Constantinesco

Ga&#xeb;lle Aubertin-Kirch

Philippe Choquet

Is Subcutaneous Route an Alternative to Intravenous Route for Mouse Contrast-Enhanced Magnetic Resonance Imaging at 1.5 T?

In medical magnetic resonance imaging, parallel radio frequency excitation pulses have to respect a large number of specific absorption rate constraints. Geometrically, each of these constraints can be interpreted as a complex, centered ellipsoid. We propose to replace a collection of such constraints by the single constraint which corresponds to the associated maximum volume inscribed ellipsoid and implies all original constraints. We describe how to compute this ellipsoid via convex programming. Examples show that this reduction has very short computation times but cuts away parts of the feasible power domain.

Kurt Majewski

Quick Reduction of Specific Absorption Rate Constraints in Parallel RF Excitation Pulse Design by Maximum Volume Inscribed Ellipsoids

<i>Purpose</i>. To investigate the value of intravoxel incoherent motion (IVIM) magnetic resonance imaging in the evaluation of the osteosarcoma (OS) response to preoperative neoadjuvant chemotherapy (NAC) in teens.<i> Methods</i>. Eighteen consecutive osteosarcoma patients (12 males and 6 females) diagnosed by histopathology were enrolled. All enrolled patients received NAC and underwent MRI examinations before and after 2 cycles of NAC. The volume (V), apparent diffusion coefficient (ADC), (slow) diffusion coefficient (D), pseudo-perfusion (fast) diffusion coefficient (D<sup>⁎</sup>or D star), and perfusion fractions (<i>f</i>) of the OS before and after NAC were measured and analysed. The sensitivity and the specificity of the ADC, D, D<sup>⁎</sup> and <svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-3.42947pt" id="M1" height="12.7178pt" version="1.1" viewBox="-0.0498162 -9.28833 8.47692 12.7178" width="8.47692pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><path id="g113-103" d="M619 670C619 686 593 712 555 712S459 686 410 634S335 504 320 430H250L219 400L222 388H312L258 73C223 -133 201 -166 187 -180C175 -191 158 -199 140 -199C123 -199 88 -188 74 -172C68 -166 63 -164 54 -171C38 -185 23 -201 23 -215C23 -236 60 -261 93 -261C122 -261 161 -247 207 -200C268 -138 300 -71 337 94C365 220 376 277 394 387L501 399L521 430H401C432 623 464 665 501 665C524 665 544 651 567 627C577 617 583 618 592 625C601 631 619 651 619 670Z"/></g></svg> values and the correlation between changes in volume (<span class="nowrap"><svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-3.227201pt" id="M2" height="11.8631pt" version="1.1" viewBox="-0.0498162 -8.6359 17.1423 11.8631" width="17.1423pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><path id="g113-133" d="M600 0V24L339 665L311 657L43 24V0H600ZM497 50H107L303 539L497 50Z"/></g><g transform="matrix(.0091,0,0,-0.0091,9.958,3.132)"><path id="g58-84" d="M698 650H468V617C551 609 555 599 536 543C506 457 432 264 379 129H377C311 297 238 488 212 560C196 604 198 609 271 617V650H21V617C80 612 98 603 127 532C183 396 268 173 335 -9H370C445 196 551 450 578 511C615 602 630 609 698 617V650Z"/></g></svg>)</span> and the IVIM-derived parameters (<span class="nowrap"><svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-3.2957pt" id="M3" height="11.9316pt" version="1.1" viewBox="-0.0498162 -8.6359 30.1309 11.9316" width="30.1309pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><use xlink:href="#g113-133"/></g><g transform="matrix(.0091,0,0,-0.0091,9.958,3.132)"><path id="g58-63" d="M682 0V33C615 38 603 49 571 134C507 305 441 494 378 665L343 655L136 136C101 48 86 41 22 33V0H246V33C170 41 161 50 183 112C196 152 209 192 224 232H441C461 176 478 126 493 87C504 49 499 41 433 33V0H682ZM425 279H242C273 363 303 448 335 533H337L425 279Z"/></g><g transform="matrix(.0091,0,0,-0.0091,16.355,3.132)"><path id="g58-66" d="M43 650V617C122 612 130 606 130 522V128C130 44 122 37 34 32V0H275C400 0 497 25 573 82C652 142 698 229 698 350C698 445 662 518 613 565C549 625 456 650 327 650H43ZM217 544C217 580 220 591 229 599C240 607 264 613 311 613C380 613 437 599 482 570C561 523 598 436 598 336C598 177 511 40 324 40C248 40 217 61 217 135V544Z"/></g><g transform="matrix(.0091,0,0,-0.0091,23.299,3.132)"><path id="g58-65" d="M618 181C565 77 513 26 413 26C264 26 151 150 151 336C151 486 240 625 407 625C516 625 573 582 600 475L634 483C627 540 622 581 613 638C585 643 518 665 435 665C211 665 46 526 46 315C46 158 157 -15 406 -15C480 -15 564 4 594 12C612 43 638 121 651 168L618 181Z"/></g></svg>,</span> <span class="nowrap"><svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-3.1815pt" id="M4" height="11.8174pt" version="1.1" viewBox="-0.0498162 -8.6359 17.3889 11.8174" width="17.3889pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><use xlink:href="#g113-133"/></g><g transform="matrix(.0091,0,0,-0.0091,9.958,3.132)"><use xlink:href="#g58-66"/></g></svg>,</span> <svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-3.1815pt" id="M5" height="11.8174pt" version="1.1" viewBox="-0.0498162 -8.6359 22.9698 11.8174" width="22.9698pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><use xlink:href="#g113-133"/></g><g transform="matrix(.0091,0,0,-0.0091,9.958,3.132)"><use xlink:href="#g58-66"/></g><g transform="matrix(.0091,0,0,-0.0091,16.728,3.132)"><path id="g50-43" d="M486 158C486 177 478 202 466 220C413 228 386 236 336 262C386 288 413 297 466 304C478 323 486 347 485 366C470 376 444 381 422 380C389 338 368 319 321 288C323 345 329 372 349 422C339 442 322 461 305 470C289 461 271 442 262 422C281 372 287 345 290 288C243 319 222 338 189 380C167 381 142 376 125 366C125 347 133 322 145 304C198 296 225 288 275 262C225 236 198 227 145 220C133 201 125 177 126 158C141 148 167 143 189 144C222 186 243 205 290 236C288 179 282 152 262 102C272 82 289 63 306 54C322 63 340 82 350 102C330 152 324 179 321 236C368 205 390 186 422 144C444 143 470 148 486 158Z"/></g></svg> and <span class="nowrap"><svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-5.529pt" id="M6" height="14.1649pt" version="1.1" viewBox="-0.0498162 -8.6359 16.4755 14.1649" width="16.4755pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><use xlink:href="#g113-133"/></g><g transform="matrix(.0091,0,0,-0.0091,9.958,3.132)"><path id="g50-103" d="M620 667C620 684 593 710 552 710C515 710 459 687 409 634C360 582 334 506 320 433H247L215 400L220 388H310L259 80C224 -129 199 -161 185 -174C175 -183 160 -192 141 -192C123 -192 90 -181 75 -165C69 -158 64 -156 54 -164C39 -178 24 -195 24 -208C24 -231 61 -257 94 -257C124 -257 162 -243 209 -194C267 -134 303 -66 343 107C369 220 378 279 393 385L503 397L523 433H404C432 619 464 660 500 660C522 660 542 646 566 621C573 614 583 615 593 621C603 628 620 648 620 667Z"/></g></svg>)</span> were also calculated and analysed. Paired Student’s t-tests, receiver operating characteristic (ROC) curves, and Spearman correlation analyses were used.<i> Results</i>. The mean volume of the OS after NAC decreased significantly (61.55±9.3 cm<sup>3</sup> vs 40.26±4.1 cm<sup>3</sup>) (P&lt;0.05). After NAC, the ADC (1.21±0.09 × 10<sup>-3 </sup>mm<sup>2</sup>/s vs 1.73±0.11 × 10<sup>-3 </sup>mm<sup>2</sup>/s) and D (1.14±0.09 × 10<sup>-3 </sup>mm<sup>2</sup>/s vs 1.63±0.1 × 10<sup>-3 </sup>mm<sup>2</sup>/s) values increased and<i> f </i>(28.58±1.37% vs 20.93±1.16%) values decreased significantly (P&lt;0.05), while D<sup>⁎</sup> (9.17±0.98 × 10<sup>-3 </sup>mm<sup>2</sup>/s vs 8.94±0.13 × 10<sup>-3 </sup>mm<sup>2</sup>/s) values changed slightly (P&gt;0.05). The AUC values of ADC (0.938) and D (0.943) were higher than those of D<sup>⁎</sup> (0.574) and<i> f </i>(0.765). The sensitivity and specificity of ADC (0.778, 1) and D (0.944, 0.833) values were superior to those of D<sup>⁎</sup> (0.278, 0.722) and<i> f </i>(0.5, 0.944) values. No significant correlations were found between the <svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-3.227201pt" id="M7" height="11.8631pt" version="1.1" viewBox="-0.0498162 -8.6359 17.1423 11.8631" width="17.1423pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><use xlink:href="#g113-133"/></g><g transform="matrix(.0091,0,0,-0.0091,9.958,3.132)"><use xlink:href="#g58-84"/></g></svg> and <span class="nowrap"><svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-3.2957pt" id="M8" height="11.9316pt" version="1.1" viewBox="-0.0498162 -8.6359 30.1309 11.9316" width="30.1309pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><use xlink:href="#g113-133"/></g><g transform="matrix(.0091,0,0,-0.0091,9.958,3.132)"><use xlink:href="#g58-63"/></g><g transform="matrix(.0091,0,0,-0.0091,16.355,3.132)"><use xlink:href="#g58-66"/></g><g transform="matrix(.0091,0,0,-0.0091,23.299,3.132)"><use xlink:href="#g58-65"/></g></svg>,</span> <span class="nowrap"><svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-3.1815pt" id="M9" height="11.8174pt" version="1.1" viewBox="-0.0498162 -8.6359 17.3889 11.8174" width="17.3889pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><use xlink:href="#g113-133"/></g><g transform="matrix(.0091,0,0,-0.0091,9.958,3.132)"><use xlink:href="#g58-66"/></g></svg>,</span> <svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-3.1815pt" id="M10" height="11.8174pt" version="1.1" viewBox="-0.0498162 -8.6359 22.9698 11.8174" width="22.9698pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><use xlink:href="#g113-133"/></g><g transform="matrix(.0091,0,0,-0.0091,9.958,3.132)"><use xlink:href="#g58-66"/></g><g transform="matrix(.0091,0,0,-0.0091,16.728,3.132)"><use xlink:href="#g50-43"/></g></svg> and <svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-5.529pt" id="M11" height="14.1649pt" version="1.1" viewBox="-0.0498162 -8.6359 16.4755 14.1649" width="16.4755pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><use xlink:href="#g113-133"/></g><g transform="matrix(.0091,0,0,-0.0091,9.958,3.132)"><use xlink:href="#g50-103"/></g></svg> values (P&gt;0.05).<i> Conclusion</i>. IVIM-derived parameters ADC and D have the potential to be imaging biomarkers for evaluation of the therapeutic response to NAC in OS patients.

Houdong Zuo

The Value of Intravoxel Incoherent Motion (IVIM) Magnetic Resonance Imaging in the Evaluation of the Osteosarcoma Response to Preoperative Neoadjuvant Chemotherapy in Teens

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<p><em>Concepts in Magnetic Resonance Part A</em> publishes research concerning the applications of magnetic resonance techniques, including magnetic resonance imaging (MRI), nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR).</p>


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Concepts in Magnetic Resonance Part A, Bridging Education and Research | Hindawi

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Concepts in Magnetic Resonance Part A publishes research concerning the applications of magnetic resonance techniques, including magnetic resonance imaging (MRI), nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR).

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Concepts in Magnetic Resonance Part A, Bridging Education and Research

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Concepts in Magnetic Resonance Part A, Bridging Education and Research