Thesis
Reference
Analyse de la cartographie T1 et de sa variation diurne des disques intervertébraux au sein d'une population jeune et asymptomatique de
50 volontaires
GALLEY, Julien
Abstract
Le but de ce travail de recherche est d'évaluer le temps de relaxation T1 des disques intervertébraux au sein d'une population jeune et en bonne santé, en utilisant différents temps d'inversion-récupération, et d'y analyser la variation diurne. Deux examens par résonance magnétique de la colonne lombaire ont été réalisés le même jour matin et soir chez chacun des 50 volontaires. Les temps de relaxation T1 ont été calculés au sein des noyaux pulpeux ainsi que des anneaux fibreux. Nous avons constaté une variation diurne significative au sein des noyaux pulpeux avec une valeur moyenne de 1142 ± 12 ms le matin et de 1085 ± 13 ms le soir. Une différence significative entre les différents niveaux a également été mise en évidence, corrélant d'autres études anatomiques. La cartographie T1 des disques intervertébraux est une technique très sensible d'évaluation du contenu en eau du disque intervertébral et présente un grand potentiel dans l'analyse longitudinale des disques intervertébraux.
GALLEY, Julien. Analyse de la cartographie T1 et de sa variation diurne des disques intervertébraux au sein d'une population jeune et asymptomatique de 50
volontaires . Thèse de doctorat : Univ. Genève, 2018, no. Méd. 10868
DOI : 10.13097/archive-ouverte/unige:101919 URN : urn:nbn:ch:unige-1019191
Available at:
http://archive-ouverte.unige.ch/unige:101919
Disclaimer: layout of this document may differ from the published version.
1 / 1
Contents lists available atScienceDirect
European Journal of Radiology
j o u r n a l h o m e p a g e :w w w . e l s e v i e r . c o m / l o c a t e / e j r a d
Real T1 relaxation time measurement and diurnal variation analysis of intervertebral discs in a healthy population of 50 volunteers
J. Galley
a,∗, G. Maestretti
b, G. Koch
a, H-M. Hoogewoud
aaDepartmentofRadiology,HFRFribourg,HôpitalCantonal,Switzerland
bDepartmentofOrthopedicSurgery,HFRFribourg,HôpitalCantonal,Switzerland
a r t i c l e i n f o
Articlehistory:
Received12July2016 Receivedinrevisedform 21November2016 Accepted1December2016
Keywords:
Musculoskeletal Spine
Intervertebraldisc MR
T1mapping
a b s t r a c t
Purpose:TomeasuretherealT1relaxationtimeofthelumbarintervertebraldiscsinayoungandhealthy population,usingdifferentinversionrecoverytimes,andassessdiurnalvariation.
Materialandmethods:IntervertebraldiscsfromD12toS1of50healthyvolunteersfrom18to25yearsold wereevaluatedtwicethesameday,inthemorningandinthelateafternoon.DedicatedMRIsequences withdifferentinversionrecoverytimes(from100to2500ms)wereusedtocalculatetherealT1relaxation time.Threeregionsofinterest(ROIs)weredefinedineachdisc,themiddlerepresentingthenucleus pulposus(NP)andtheouterpartstheannulusfibrosus(AF)anteriorandposterior.Diurnalvariationand differencesbetweeneachdisclevelwereanalyzed.
Results:T1meanvaluesintheNPwere1142±12msinthemorningand1085±13msintheafternoon, showingahighlysignificantdecreaseof57ms(p<0.001).Ahighlysignificantdifferencebetweenthe levelsofthespinewasfound.ThemeanT1oftheanteriorpartoftheAFwas577±9msinthemorning and554±8msintheafternoon.Fortheposteriorpart,themeanvalueswere633±8msinthemorning and581±7msintheevening.Itshowsahighlysignificantdecreaseof23msfortheanteriorpartand 51msfortheposteriorpart(allp<0.001).
Conclusion:T1mappingisapromisingmethodofintervertebraldiscevaluation.Significantdiurnal variationanddifferencebetweenlevelsofthelumbarspineweredemonstrated.Apotentialusefor longitudinalstudyinpost-operativefollowuporsportmedicineneedstobeevaluated.
©2016ElsevierIrelandLtd.Allrightsreserved.
1. Introduction
Backpainisverycommonbutchallengingmedicalcondition thatoftenaffectsyoungindividualsandhasamajorimpactonwork capacity[1].Althoughitsestablishedassociationwithinterverte- braldiscdegenerationandthefactthatthephysiopathologyhas beenthoroughlystudied[2,3],thecascadeofeventsleadingtoclin- icalmanifestationarenotfullyunderstood.Besides,asignificant numberofpeoplepresentingdiscdegenerationareasymptomatic [4,5].
Theintervertebraldiscis composedofanoutershellknown astheannulusfibrosous(AF)andaninnerpart,thenucleuspul- posous(NP).TheAFconsistsof15–25lamellaeofcollagenstrongly attachedtotheendplatesandreinforcedbythetwolongitudinal ligaments. It confersthetensile and shearstrength ofthe disc.
TheNPcontainscollagenfibers,elasticfibersandagel-likearea
∗Correspondingauthor.
E-mailaddress:galleyjulien@gmail.com(J.Galley).
ofproteoglycans(PGs)withhydrophilicchondroitinand keratin sulfate,whichbindwatermolecules[2].Alterationofthesecom- ponentsseenduringdiscdegenerationwillimpactthemechanical propertiesandcauseaprogressivelossofthediscwatercontent.
Eventhoughintervertebraldisccomponentsarethesame,each discof thelumbar spinecan beconsidered asa unique entity.
Theintervertebraldiscispartofacomplexstructuremadeofthe endplates,thediscitself,numerousligamentousstructures(longi- tudinalanteriorandposterior,flavum,interspinous,supraspinous, intertransverse),musclesandfacetjoints.Atbothendsofthelum- bar spine, thedorsolumbar and lumbosacral junction will also influencethemotionoftheadjacentdiscs.Allthoseinteractions willmakethediscsactdifferently.Thedegrees ofmovementof eachlevelhasbeenshowntobedistinct[6–8].
Imagingasaroutineexaminationisstill controversialatthe onsetofsymptoms[9].However,ifneeded,MRIisnowconsid- eredasthenon-invasivemethodofchoicetoanalyzeintervertebral disccomponents.ItallowscleardistinctionbetweentheAFand NPwithhighspatialresolution.SagittalT2-weightedimageshave becomethefirstlineanalysistoevaluateintervertebraldiscshydra- http://dx.doi.org/10.1016/j.ejrad.2016.12.001
0720-048X/©2016ElsevierIrelandLtd.Allrightsreserved.
14 J.Galleyetal./EuropeanJournalofRadiology87(2017)13–19
Table1 MRIparameters.
Inversionrecoverysequences
Sequences SagittalT1 SagittalT2 SagIRTI100 SagIRTI200 SagIRTI400 SagIRTI600 SagIRTI900 SagIRTI1200 SagIRTI1800 SagIRTI2500
TE MinFull 102 MinFull MinFull MinFull MinFull MinFull MinFull MinFull MinFull
TR 340 3547 5775 5775 5775 5775 5775 5775 5775 5775
TI – – 100 200 400 600 900 1200 1800 2500
Echotrainlength 3 23 12 12 12 12 12 12 12 12
FOV 34 34 26 26 26 26 26 26 26 26
Matrix 384×224 320×256 288×160 288×160 288×160 288×160 288×160 288×160 288×160 288×160
Slicethickness 3.5 3.5 6 6 6 6 6 6 6 6
Slicespacing 1 1 3 3 3 3 3 3 3 3
Numberofslices 15 15 3 3 3 3 3 3 3 3
Acquisitiontime 03:08 02:58 01:38 01:38 01:38 01:38 01:38 01:38 01:38 01:38
TE=echotime,TR=repetitiontime,TI=inversionrecoverytime.
tion.AfivegradesclassificationwasproposedbyPfirrmann[10]
and is commonlyaccepted asthe referencequalitative grading system.Severalquantitiveanalyseshavebeenevaluatedusingdif- ferentMRItechniques.T1rhoimaging[11–16]hasbeenprovento beasensitivetoolforearlydiscdegenerationchangesdetection, showingacorrelationbetweentheT1rhovaluesandproteogly- cancontent.T1rhodiffersfromrealT1bythefactthatithasboth elementsofT1andT2weightening[17].QuantitativeT2approach alsoseemstobesensitivetoearlydegeneration[16,18–20].
Ithasalsobeenshownthatdiurnalchangesoccurinnormal intervertebraldiscsusinglumbarlengthmeasurement(heightloss) andT2mapping(decreasingT2values)[21,22].
T1mappinghasbeenevaluatedindifferentpartofthebody, likebrain[23]andcartilage[24–26]andwasdemonstratedtobe correlatedtowatercontent[27,28].Butinthecurrentliterature thereisalackofstudiesaboutT1relaxationtimemeasurementin theintervertebraldiscs.
Thepurposeofthisstudywastodefinereferencevaluesina youngandhealthypopulationandtoanalyzeitsdiurnalvariation.
2. Materialsandmethods
ThisstudywasapprovedbytheCTCER(Communautédetravail desCommissionsSuissesd’éthiquepourlarecherchesurl’êtrehumain, Lausanne)
2.1. Participants
Fiftyhealthy and asymptomaticvolunteerswereincludedin thisstudy:meanage21.6±2.4,agerange18–25years,23females and27males.Recruitmentforthestudywasfrommedicalstaff oracquaintancesanduniversitystudents.Thenumberofsubjects wasestimatedusingF-testbasedondatawemeasuredon20symp- tomaticpatients.
Eachparticipantwasaskedtofillformsabouttheirhealthhis- toryandmedication.
Inclusioncriteriawere:goodhealth,absenceofanybacksymp- tom,agebetween18–25years.
Exclusioncriteriawere:medicalhistoryofbackpain,radicu- lopathyorneurologicaldeficit,backtrauma,previousbacksurgery orinfiltration, osteoarticular or connective tissue disease,body massindexof>25,contraindicationtoMRI.
Alltheparticipantswereaskedtohavenormaldaytimeactivity andtoavoidanyheavywork(nottobearweightsover10kg)or anysportduringthedayofexamination.
Writteninformedconsentwasobtainedfromallparticipants.
2.2. MRimaging
Theexaminationswereperformedbetweenthe23thDecember 2014and14thJuly2015.Allthevolunteerswerescannedtwice thesameday(onceinthemorningat8amandonceinthelate afternoonaround5pm)inarelaxsupineposition.
MRimagingwasperformedusinga1.5TMRunit(Optima360 Advance,GEHealthcare,Waukesha,WI,USA).
ThestandardMRprotocolusingsagittalT1-weightedfastspin echoandsagittalT2-weightedfastspinechosequenceswasused for morphological analysis and Pfirrmann classification of each disc.Dedicatedsequences were then realizedfor T1 relaxation timemeasurements.Asconductedbefore[27],weusedtheinver- sionrecoverytechniqueswithdifferentinversionrecoverytimes (from 100 to 2500ms). The detailed parameters are shown in Table 1. T1 relaxation timeswere obtained usingsoftware (T1 Mapping-FunctoolResearch,AdvantageWindowsWorkstationGE, Milwaukee) calculatingthe curveof thelongitudinalrelaxation fromthesignalvalues measuredpixel bypixelonthedifferent inversiontimes.Thevalueobtainedforarelaxationof63%ofits maximalvalueisconsideredastherealT1relaxationtimeofthe tissue[29–31](Fig.1).Foradefinedregionofinterest(ROI),theT1 valueisdefinedastheaveragevalueofallthepixelscontainedin thisdefinedarea.
2.3. Imageanalysis
Sixintervertebraldiscs(D12-S1)wereexaminedforeachexam ofallparticipants.Sixhundredintervertebraldiscswereseparately analyzed.AlldiscswereclassifiedaccordingtothePfirrmannclas- sificationbasedontheT2-weightedimages.
ForT1relaxationtimemeasurement,wehadtodefinediffer- entregionsofinterest(ROIs)throughoutthediscinthesagittal plane.Differentpreviousstudies[19,20]defined5equalROIsfrom
Fig.1. Schematiccurvedrawnbythedifferentinversionrecoverytimesvalues(blue dots).T1isdefinedasthetimeat63%ofthefullrecovery.
Fig.2. Discsegmentationwith3differentROIs(RegionOfInterest):Ontheleft,ROIplacement:themiddleonethenucleuspulposus(NP),thetwoouterpartsrepresenting theannulusfibrosus(AF).Ontheright,exampleofalltheROIofanexamfromD12toS1.
1000 1020 1040 1060 1080 1100 1120 1140 1160
Morning Afternoon
Relaxation time (ms)
NP
T1 relaxation time mean value
Fig.3.T1relaxationtimemeanvalues(ms)oftheNPofallthediscs.Errorbarsrepresent95%confidenceinterval.NP=nucleuspulposus.
anteriortoposterior,thenumber1and5representingtheannulus fibrosusandthethreeinthemiddle(number2–4)thenucleuspul- posus.WeoptforthreeROIsintotalrepresentinganatomicarea.
Twovirtualhorizontallinesoftheouterborderofeachendplates weredefined.AnovoidROIbetweenthoselines,lessthanhalfofthe lengthofthedisc,centeronthemiddle,wasconsideredtobethe nucleuspulposusarea.TworoundROIs,lessthanfifthofthetotal length,wereplacedonthetwoouterpartofthediscanddefined astheannulusfibrosusarea(Fig.2).Allthemeasuresweredoneby oneradiologistwith4yearsofradiologyand2yearsoforthope- dicandspinesurgeryexperience.Theintraobserverreliabilitywas evaluatedontenpatientswithacorrelationcoefficientof>0.9.
2.4. Statisticalanalysis
Independentsamplest-testwereperformedtoanalyzethedif- ferencebetweentwogroups(morningvsafternoon).APvalueof
≤0.05wasconsideredtobesignificantand aPvalueof ≤0.001 highlysignificant.Wehaveconsideredaconfidenceintervalreflect- ingasignificancelevelof5%.Tocomparethedifferentlevelsofthe spineagainsttheothers,ANOVAtestwithpost-hocBonferroniwas realized.AllthetestandgraphswererealizedusingMicrosoftExcel version14.5.5andSSPSstatistic23.
3. Results
In total,600intervertebraldiscs wereevaluated (50partici- pants,6discsfromD12toS1,2examinationsthesameday).Using theaforementionedmethod,1800ROIsweredrawn.
Allthediscswereclassifiedaccordingtothe5gradesPfirrmann classification.Wefound584discsclassifiedgradeIorII,14grade IIIand2gradeIV.GradesIandIIdiscswereconsideredrepresenta- tiveofnormaldiscandusedformeasurementstodefinereference values.
3.1. Nucleuspulposus(NP)
ThemeanT1relaxationtimevaluesoftheNParerepresented inTable2.
Themeanvalueofalldiscstogetherwas1142±12msatthe morningexaminationand1085±13msintheafternoon(Fig.3).
Thedecreasebetweenthesetwogroupsishighlysignificantwitha Pvalue<0.001.Eachlevelseparatelyshowedahighlysignificant difference(Pvalue<0.001)betweenthemorningandafternoon values.
Thedifferencebetweenthelevels(ANOVA)washighlysignifi- cant(Pvalue<0.001).Comparingthedifferentlevelstoeachother (post-hocBonferroni),themajorityofpairsofweresignificantly different(Table3).
Thehighestmeanvalues(forthemorningaswellastheafter- noon)weremeasuredin L4-L5(morning1234±11ms,evening 1181±23ms).Wenoticedthetendencyofaprogressiveincrease ofvaluesfromD12-L1toL4-L5beforedecreasinginL5-S1(Fig.4).
Themeandelta(differencebetweenmorningandafternoonval- ues)foralllevelswas−57ms(1142-1085).Andtakenseparately, wenoticedaninvertedtendencywithprogressivedecreasefrom D12-L1untilthelowestlevel L3-L4(40±5ms)beforegoingup again.
16 J.Galleyetal./EuropeanJournalofRadiology87(2017)13–19
600 700 800 900 1000 1100 1200 1300
D12-L1 L1-L2 L2-L3 L3-L4 L4-L5 L5-S1
Relaxation time (ms)
NP Mean Value
Morning Afternoon
Fig.4. T1Relaxationtimemeanvalues(ms)formorningandafternoonforeachlevel.Errorbarsrepresent95%confidenceinterval.NP=nucleuspulposus.
Table2
Nucleuspulposusmeanvalues.
Level Mean CI Pvalue
Alldiscs
Morning 1142,0 12,2 <0,001*
Afternoon 1085,4 13,4
D12-L1
Morning 1032,0 20,3 <0,001*
Afternoon 952,8 23,5
L1-L2
Morning 1079,5 20,9 <0,001*
Afternoon 1018,2 23,7
L2-L3
Morning 1050,0 18,9 <0,001*
Afternoon 1102,4 22,6
L3-L4
Morning 1191,1 19,9 <0,001*
Afternoon 1153,1 20,8
L4-L5
Morning 1234,3 25,0 <0,001*
Afternoon 1181,4 23,3
L5-S1
Morning 1167,4 29.2 <0,001*
Afternoon 1105,0 28,6
CI:confidenceinterval.
* Pvalue≤0.001.
3.2. Annulusfibrosus(AF)
ThemeanT1relaxationtimevaluesoftheAFarerepresentedin Table4.
ThemeanvaluefortheanteriorpartoftheAFforallthediscs was577±9msinthemorningand554±8msintheafternoon.For theposteriorpart,themeanvalueswere633±8msinthemorning and581±7msintheevening(Fig.5).Thatshowsahighlysignifi- cantdifference(Pvalue<0.001)betweentheanteriorandposterior partofthe annulusfibrosus,thehighest values concerningthe posteriorpart.Italsodemonstratesahighlysignificantdifference (Pvalue<0.001)betweenmorningandafternoonfortheanterior (−23ms)aswellastheposteriorpart(–51ms)oftheAF.Taken separately,eachlevelalsoshowedasignificantdifferencebetween morningandafternoonfortheanteriorandposteriorpart.Asfor theNPvalues,wenoticedatendencyofincreasingvaluesfromD12 toL4/L5andthendecreasingfortheanteriorpartoftheannulusbut notforposteriorpart(Figs.6and7).Themeandelta(absolutedif-
Table3
Nucleuspulposuslevelscomparison(Post-hocBonferonni).
(I)Group (J)Group Averagedifference(I-J) Significance D12-
L1
L1-L2 −47.5 0.066
L2-L3 −118.08 <0,001*
L3-L4 −159.1224 <0,001*
L4-L5 −202.2917 <0,001*
L5-S1 −135.3902 <0,001*
L1- L2
D12-L1 47.5 0.066
L2-L3 −70.58 <0,001*
L3-L4 −111.6224 <0,001*
L4-L5 −154.7917 <0,001*
L5-S1 −87.8902 <0,001*
L2- L3
D12-L1 118.08 <0,001*
L1-L2 70.58 <0,001*
L3-L4 −41.0424 0.185
L4-L5 −84.2117 <0,001*
L5-S1 −17.3102 1
L3- L4
D12-L1 159.1224 <0,001*
L1-L2 111.6224 <0,001*
L2-L3 41.0424 0.185
L4-L5 −43.1692 0.138
L5-S1 23.7322 1
L4- L5
D12-L1 202.2917 <0,001*
L1-L2 154.7917 <0,001*
L2-L3 84.2117 <0,001*
L3-L4 43.1692 0.138
L5-S1 66.9014 0.002*
L5- S1
D12-L1 135.3902 <0,001*
L1-L2 87.8902 <0,001*
L2-L3 17.3102 1
L3-L4 −23.7322 1
L4-L5 −66.9014 0.002**
*Pvalue≤0.001.
**Pvalue≤0.05.
ferencebetweenmorningandafternoon)didn’tshowanincreasing ofdecreasingcurve.
4. Discussion
ThisstudyprovidesquantitativeT1relaxationtimevaluesfor lumbarintervertebraldiscsinayoungandhealthypopulation.As expected,theresultsshowsignificantdifferencebetweentheAF andtheNP,explainedbytheirdifferentcomponents.Thediurnal T1variationbetweenmorningandafternoon(decreasingvalues) wassignificantlydemonstratedfortheNPandtheAFofalllevels.It correlatestheresultsofpreviousstudiesshowingdiurnalvariation withdecreasingT2values[20,22].Thisdailyevolvingstatuscanbe explainedbythelossofwatercontentandcollagenfibersorienta-
400 450 500 550 600 650 700
Morning Afternoon Morning Afternoon
Ant Post
Relaxation time (ms)
AF
T1 relaxation time mean value
Fig.5.T1relaxationtimemeanvalues(ms)fortheanteriorandposteriorpartoftheAF.Errorbarsrepresent95%confidenceinterval.AF=annulusfibrosus.
300 350 400 450 500 550 600 650 700
D12-L1 L1-L2 L2-L3 L3-L4 L4-L5 L5-S1
Relaxation time (ms)
Anterior AF mean value
Morning Afternoon
Fig.6.T1relaxationtimemeanvalues(ms)fortheanteriorpartoftheAFofeachlevel.Errorbarsrepresent95%confidenceinterval.AF=annulusfibrosus.
300 350 400 450 500 550 600 650 700
D12-L1 L1-L2 L2-L3 L3-L4 L4-L5 L5-S1
Relaxation time (ms)
Posterior AF mean value
Morning Afternoon
Fig.7. T1relaxationtimemeanvalues(ms)fortheposteriorpartoftheAFofeachlevel.Errorbarsrepresent95%confidenceinterval.AF=annulusfibrosus.
18 J.Galleyetal./EuropeanJournalofRadiology87(2017)13–19
Table4
Annulusfibrosusmeanvalues.
Level Mean CI Pvalue
Alldiscs
Anterior Morning 577,3 8,5 <0,001*
Afternoon 554,0 8,3
Posterior Morning 632,6 8,4 <0,001*
Afternoon 581,0 7,0
D12-L1
Anterior Morning 536,8 13,0 <0,001*
Afternoon 506,7 12,6
Posterior Morning 628,6 18,2 <0,001*
Afternoon 573,5 19,6
L1-L2
Anterior Morning 552,1 15,4 <0,001*
Afternoon 528,8 14,0
Posterior Morning 642,8 19,4 <0,001*
Afternoon 579,5 16,2
L2-L3
Anterior Morning 564,3 16,2 <0,001*
Afternoon 539,4 15,6
Posterior Morning 636,5 20,0 <0,001*
Afternoon 584,5 12,2
L3-L4
Anterior Morning 579,4 17,2 0,012**
Afternoon 562,0 14,7
Posterior Morning 620,4 14,4 <0,001*
Afternoon 574,8 10,1
L4-L5
Anterior Morning 627,1 20,1 0,041**
Afternoon 606,8 20,9
Posterior Morning 644,0 23,5 <0,001*
Afternoon 590,0 13,7
L5-S1
Anterior Morning 609,7 26,9 0,048**
Afternoon 585,2 25,0
Posterior Morning 621,6 23,9 <0,001*
Afternoon 584,1 26,3
CI:confidenceinterval.
* Pvalue≤0.001.
** Pvalue≤0.05.
tionvariationinthediscduetothediurnalaxialload[20,32].All thosestructuralchangeswillinfluencetheT1.
Asaboved-mentioned,T1iscorrelatedtothehydrationstate ofthetissueand thereforeitscomponents.Aninteresting point supportedbythisstudyisthedifferencebetweenthelevelsofthe spine.DifferentT1valuesshowthateachlevelisaproperentity withslightlydifferentdischydrationstate(andthereforecompo- nents).Blumenkrantzetal.[12]aswellasZobeletal.[13]already mentionedadifferencebetweenlevelsusingtheT1rhomapping.
Wemanagedtoprovethisdifferencewithsignificantvalues,due tothelargernumberofsubjects.
AsprovenbyCooketal.[8],thelumbarspineshowsasignificant differentrangeofmotionbetweeneachlevel.Theyanalyzedthree differentrangeofmotion:flexionextension(FE),lateralbending (LB)andaxialtorsion(AT).FErangeofmotiontendedtoincrease fromL1toS1.Ontheotherhand,LBandATrangeofmotiontended tobegreaterincenterofthesegmentwiththehighestvaluesin L4-L5.Ourvaluesalsoshowthistendency,growingfromD12-L1 toL4-L5beforegoingdowninL5-S1.Asdiscussedearlier,theT1 iscorrelatedtothehydrationstateofthedisc.So,comparingour datawiththestudyofCooketal.,wecanpostulatethatthereis acorrelationbetweenthehydrationstateandthemobilityofthe disc(forLBandAT).
This tendency was inverted for the mean delta (difference betweenmorningandafternoon)withthelowestvalueinL3and
L4.Thusthemorehydratedisadisc,thelesswateritwillloseduring theday.
Animportantlimitationinourstudyistheanalysisoftheannu- lusfibrosus.TheplacementsoftheROIs(regionofinterest)were difficultduetotheconvexshapeofthedisc.Insomecases,theROI hadtobereallysmalltofitbetweenthetwoendplates.AsmallROI willbeeasilyinfluencedwithlittledisplacementormisplacement.
Itcouldbeaproblemforreproducibilityandthatshouldbeconsider forfurtherevaluation.Anotherquestionisthestudiedpopulation (mostlystudents)thatmaynotberepresentativeofthecurrent population(nopracticalworkerforinstance)andcouldbeabias.
Inversionrecoverytechniqueusedforthisstudyistimecon- sumingandmaynotbeapplicableindailypractice.Itstillhasto beprovenifusinglessIRtimestoshortentheprotocolandgain precioustimeisaccurateenough.
To ourbest actual knowledge, our studyis thefirst one to investigateintervertebraldiscT1relaxationtimeusinginversion- recovery. This work only evaluates discs of asymptomatic volunteersandthenextstepwillbetheanalysisofpathologicdiscs insymptomaticpatients.AcorrelationbetweentheT1valuesand thePfirrmanngradesshouldbefoundbutstilltobedemonstrated.
Thismethodalsoseemspromising forlongitudinalanalysis,for instancefor thefollowupof discsafterspinedynamic fixation surgery.Potentialuseinsportmedicinealsoseemsinteresting,for exampleinanalyzingtheimpactofdifferenttrainingtechniquesor materiels(i.e.shoes)inlongdistancerunning.
Inconclusion,T1relaxationtimemeasurementusingdifferent inversion recoverytimesseemspromisingfor theevaluationof (patho)physiologicalchangesoftheintervertebraldiscsandshows potentialforfurtherevaluation.
Conflictsofinterest
Theauthorswhosenamesarelistedimmediatelybelowcertify that theyhaveNO affiliationwithor involvement in anyorga- nizationorentitywithanyfinancialinterest(suchashonoraria;
educationalgrants;participationinspeakers’bureaus;member- ship,employment,consultancies,stockownership,orotherequity interest;andexperttestimonyorpatent-licensingarrangements), ornon-financialinterest(suchaspersonalorprofessionalrelation- ships,affiliations,knowledgeorbeliefs)inthesubjectmatteror materialsdiscussedinthismanuscript.
Acknowledgment
Fundingforthisstudywasprovidedbytheresearchfundofthe departmentofRadiologyoftheHôpitalHFRFribourg.
References
[1]D.Hoy,P.Brooks,F.Blyth,R.Buchbinder,TheEpidemiologyoflowbackpain, BestPract.Res.Clin.Rheumatol.24(December(6))(2010)769–781.
[2]A.Colombini,G.Lombardi,M.M.Corsi,G.Banfi,Pathophysiologyofthe humanintervertebraldisc,Int.J.Biochem.CellBiol.40(5)(2008)837–842.
[3]H.Shankar,J.A.Scarlett,S.E.Abram,Anatomyandpathophysiologyof intervertebraldiscdisease,TechRegAnesthPainManag.13(April(2))(2009) 67–75.
[4]M.C.Jensen,M.N.Brant-Zawadzki,N.Obuchowski,M.T.Modic,D.Malkasian, J.S.Ross,Magneticresonanceimagingofthelumbarspineinpeoplewithout backpain,N.Engl.J.Med.331(July(2))(1994)69–73.
[5]S.D.Boden,D.O.Davis,T.S.Dina,N.J.Patronas,S.W.Wiesel,Abnormal magnetic-resonancescansofthelumbarspineinasymptomaticsubjects:a prospectiveinvestigation,J.BoneJointSurg.Am.72(March(3))(1990) 403–408.
[6]D.Allbrook,Movementsofthelumbarspinalcolumn,J.BoneJointSurg.Br.1 (39-MayB(2))(1957)339–345.
[7]A.A.White,M.M.Panjabi,Thebasickinematicsofthehumanspine:areview ofpastandcurrentknowledge,Spine3(March(1))(1978)12–20.
[8]D.J.Cook,M.S.Yeager,B.C.Cheng,Rangeofmotionoftheintactlumbar segment:amultivariatestudyof42lumbarspines,Int.J.SpineSurg.9(2015) 5.
[9]H.J.Jenkins,M.J.Hancock,C.G.Maher,S.D.French,J.S.Magnussen, Understandingpatientbeliefsregardingtheuseofimaginginthe managementoflowbackpain,Eur.J.PainLond.Engl.(August(18))(2015).
[10]C.W.Pfirrmann,A.Metzdorf,M.Zanetti,J.Hodler,N.Boos,Magnetic resonanceclassificationoflumbarintervertebraldiscdegeneration,Spine26 (September(17))(2001)1873–1878.
[11]W.Johannessen,J.D.Auerbach,A.J.Wheaton,A.Kurji,A.Borthakur,R.Reddy, etal.,Assessmentofhumandiscdegenerationandproteoglycancontent usingT1rho-weightedmagneticresonanceimaging,Spine31(May(11)) (2006)1253–1257.
[12]G.Blumenkrantz,X.Li,E.T.Han,D.C.Newitt,J.C.Crane,T.M.Link,etal.,A feasibilitystudyofinvivoT1imagingoftheintervertebraldisc,Magn.
Reson.Imaging24(October(8))(2006)1001–1007.
[13]B.B.Zobel,G.Vadalà,R.DelVescovo,S.Battisti,F.M.Martina,L.Stellato,etal., T1magneticresonanceimagingquantificationofearlylumbarintervertebral discdegenerationinhealthyyoungadults,Spine14(June(14))(2012) 1224–1230.
[14]J.D.Auerbach,W.Johannessen,A.Borthakur,A.J.Wheaton,C.A.Dolinskas,R.A.
Balderston,etal.,Invivoquantificationofhumanlumbardiscdegeneration usingT1-weightedmagneticresonanceimaging,Eur.SpineJ.(Aug(Suppl.
3))(2006)338–344.
[15]A.M.Nguyen,W.Johannessen,J.H.Yoder,A.J.Wheaton,E.J.Vresilovic,A.
Borthakur,etal.,Noninvasivequantificationofhumannucleuspulposus pressurewithuseofT1rho-weightedmagneticresonanceimaging,J.Bone JointSurg.Am.90(April(4))(2008)796–802.
[16]G.Blumenkrantz,J.Zuo,X.Li,J.Kornak,T.M.Link,S.Majumdar,Invivo 3.0-TeslamagneticresonanceT1andT2relaxationmappinginsubjectswith intervertebraldiscdegenerationandclinicalsymptoms,Magn.Reson.Med.
63(May(5))(2010)1193–1200.
[17]WángY-XJ,Q.Zhang,X.Li,W.Chen,A.Ahuja,J.Yuan,T1magnetic resonance:basicphysicsprinciplesandapplicationsinkneeand intervertebraldiscimaging,Quant.ImagingMed.Surg.5(December(6)) (2015)858–885.
[18]G.Niu,J.Yang,R.Wang,S.Dang,E.X.Wu,Y.Guo,MRimagingassessmentof lumbarintervertebraldiskdegenerationandage-relatedchanges:apparent diffusioncoefficientversusT2quantitation,AJNRAm.J.Neuroradiol.32 (October(9))(2011)1617–1623.
[19]D.Stelzeneder,G.H.Welsch,B.K.Kovács,S.Goed,T.Paternostro-Sluga,M.
Vlychou,etal.,QuantitativeT2evaluationat3.0Tcomparedtomorphological gradingofthelumbarintervertebraldisc:astandardizedevaluationapproach inpatientswithlowbackpain,Eur.J.Radiol.81(February(2))(2012) 324–330.
[20]D.Stelzeneder,B.K.Kovács,S.Goed,G.H.Welsch,C.Hirschfeld,T.
Paternostro-Sluga,etal.,Effectofshort-termunloadingonT2relaxationtime inthelumbarintervertebraldisc–invivomagneticresonanceimagingstudy at3.0tesla,SpineJ.12(March(3))(2012)257–264.
[21]O.Karakida,H.Ueda,M.Ueda,T.Miyasaka,DiurnalT2valuechangesinthe lumbarintervertebraldiscs,Clin.Radiol.58(May(5))(2003)389–392.
[22]T.Zhu,T.Ai,W.Zhang,T.Li,X.Li,SegmentalquantitativeMRimaginganalysis ofdiurnalvariationofwatercontentinthelumbarintervertebraldiscs, KoreanJ.Radiol.16(1)(2015)139–145.
[23]H.Vrenken,J.J.G.Geurts,D.L.Knol,L.N.vanDijk,V.Dattola,B.Jasperse,etal., Whole-BrainT1mappinginmultiplesclerosis:globalchangesof
normal-appearinggrayandwhitematter,Radiology240(September(3)) (2006)811–820.
[24]E.E.Bron,J.vanTiel,H.Smit,D.H.J.Poot,W.J.Niessen,G.P.Krestin,etal., ImageregistrationimproveshumankneecartilageT1mappingwithdelayed gadolinium-enhancedMRIofcartilage(dGEMRIC),Eur.Radiol.23(January (1))(2013)246–252.
[25]A.Guermazi,F.W.Roemer,H.Alizai,C.S.Winalski,G.Welsch,M.Brittberg, etal.,Stateoftheart:MRimagingafterkneecartilagerepairsurgery, Radiology277(September(1))(2015)23–43.
[26]S.Nebelung,B.Sondern,S.Oehrl,M.Tingart,B.Rath,T.Pufe,etal.,Functional MRimagingmappingofhumanarticularcartilageresponsetoloading, Radiology26(August)(2016)160053.
[27]J.M.Shiguetomi-Medina,M.Gottliebsen,M.S.Kristiansen,S.Ringgaard,H.
Stødkilde-Jørgensen,O.Rahbek,etal.,Water-contentcalculationingrowth plateandcartilageusingMRT1-mappingdesignandvalidationofanew methodinaporcinemodel,SkeletalRadiol.42(October(10))(2013) 1413–1419.
[28]A.Schwarcz,Z.Berente,E.Ösz,T.Dóczi,Fastinvivowaterquantificationin ratbrainoedemabasedonT1measurementathighmagneticfield,Acta Neurochir.(Wien)144(8)(2016)811–816.
[29]Frontmatter,in:B.K.Vetter(Ed.),ComprendreL’IRM(7eéditionEntièrement révisée),ElsevierMasson,Paris,2011(cited2015Dec3).
[30]HowDoesMRIWork?SpringerBerlinHeidelberg,Berlin,Heidelberg,2006 [cited2016Oct18].Availablefrom:
http://link.springer.com/book/10.1007%2F978-3-540-37845-7.
[31]M.A.Bernstein,K.F.King,X.J.Zhou,HandbookofMRIPulseSequences, Elsevier,2004(1041p.).
[32]S.C.Drew,P.Silva,S.Crozier,M.J.Pearcy,AdiffusionandT2relaxationMRI studyoftheovinelumbarintervertebraldiscundercompressioninvitroPhys.
Med.Biol.49(August(16))(2004)3585–3592.
