Response o he le e ‘Syn he ic double in e sion eco e y (DIR) and phase-
sensi i e in e sion eco e y (PSIR) images showed be e delinea ion o mul iple
scle osis plaques’
F ancesc Xa ie Ayme ich 1,2, Àlex Ro i a 1
A ilia ions
1 Sec ion o Neu o adiology, Depa men o Radiology (Ins i u de Diagnòs ic pe la
Ima ge), Vall d’Heb on Hospi al Uni e si a i, Vall d’Heb on Ins i u de Rece ca
(VHIR), Uni e si a Au ònoma de Ba celona, Pg Vall d’Heb on 119‐129, 08035
Ba celona, Spain
2 Depa men o Au oma ic Con ol (ESAII), Uni e si a Poli ècnica de Ca alunya,
Ba celona, Spain
Co esponding au ho :
F ancesc Xa ie Ayme ich
[email p o ec ed]
Funding
No unding was ecei ed o his s udy.
Decla a ions
E hical app o al
N/a o le e
In o med consen
N/a o le e .
Con lic s o in e es
F.X. Ayme ich has no hing o disclose.
A. Ro i a se es on scien i ic ad iso y boa ds o No a is, Sano i-Genzyme,
Syn he ic MR, Roche, Biogen, and OLEA Medical, and has ecei ed speake
hono a ia om Sano i-Genzyme, B acco, Me ck-Se ono, Te a Pha maceu ical
Indus ies L d, No a is, Roche, and Biogen.
Dea Edi o ,
Wi h g ea in e es we ead he le e 1 in esponse o ou o iginal a icle en i led
“Assessmen o 2D con en ional and syn he ic MRI in mul iple scle osis”2, in which
hey men ion he disc epancies o ou s udy wi h a p e ious one3 ega ding he
sensi i i y o Syn he ic in compa ison wi h con en ional MRI sequences in
de ec ing demyelina ing b ain lesions in pa ien s wi h mul iple scle osis (MS).
Fi s , we would like o hank Nakaya and colleagues o b inging o ligh he alue
o double in e sion eco e y (DIR) and phase-sensi i e in e sion eco e y (PSIR),
sequences, pa icula ly in combina ion, o de ec ing co ical demyelina ing lesions
in MS, which has been demons a ed in di e en s udies 4-8. De ec ion o co ical
lesions no only con ibu e in he diagnosis, bu also in p edic ing he p ognosis o
MS9-10
In ela ion wi h he le e , we mus men ion ha he aim o ou s udy was o
compa e no only he sensi i i y o con en ional and Syn he ic MR images in
de ec ing demyelina ing lesions in MS pa ien s, bu also o e alua e global image
quali y, con as , low a e ac s, and con idence in lesion assessmen .
Conside ing his objec i e, we included in ou compa ison s udy only hose
sequences, which acco ding o he ecen MAGNIMS-CMSC-NAIMS
ecommenda ion a icle11 a e conside ed manda o y in clinical p ac ice. As DIR
and PSIR sequences a e only conside ed op ional in his ecommenda ion a icle,
hey a e no ou inely ob ained in ou clinical MRI p o ocol, and he e o e we
could no make a compa ison analysis o hese wo sequences.
Al hough DIR, pa icula ly in a 3D acquisi ion, as well as hea ily 3D T1-weigh ed
sequences con as s such as PSIR can imp o e he accu acy in de ec ing co ical
MS lesions, hese sequences a e no ou inely pe o med on egula basis, due o
he ac ha his would subs an ially inc ease he MRI acquisi ion ime, and since
hei in e p e a ion, pa icula ly DIR, can be challenging leading o high in e - a e
a iabili ies.12 Fo ha eason in he MAGNIMS-CMSC-NAIMS ecommenda ion
a icle, hese wo sequences we e conside ed op ional and only ecommended o
hose cen e s wi h a high- le el o expe ise in in e p e ing MRI exams in MS, and
wi h special in e es in de ec ing co ical lesions o diagnos ic, p ognos ic o
moni o ing pu poses.
Mo eo e , he s udy o Hagiwa a e al. 3 used a global app oach in he compa ison
analysis o con en ional and Syn he ic sequences, while in ou s udy2 we
compa ed each sequence indi idually. This ac , oge he wi h he non-inclusion in
ou s udy o DIR and PSIR in ou s udy likely explain he disc epancies be ween
he wo s udies ega ding he highe sensi i i y o Syn he ic images han
con en ional images ound in he s udy o Hagiwa a e al. 3 , in compa ison o ou s,
in which we did no ind signi ican di e ences in he numbe o lesions de ec ed
o mos o he s udy egions be ween con en ional and Syn he ic images2.
Finally, we ag ee wi h Nakaya and colleagues ha Syn he ic MRI sequence o e s
ad an ages, as i does no equi e spending addi ional ime o acqui e DIR and
PSIR sequences in addi ion o con en ional sequences, and he e o e i is a
p omising echnique ha could acili a e he inclusion o hese op ional sequences
in clinical p ac ice.
Re e ences
1. Nakaya M, Hagiwa a A, Ho i M, e al. (2022) Syn he ic double in e sion
eco e y (DIR) and phase-sensi i e in e sion eco e y (PSIR) images
showed be e delinea ion o mul iple scle osis plaques. Neu o adiology
2. Ayme ich FX, Auge C, Alonso J, e al (2022) Assessmen o 2D con en ional
and syn he ic MRI in mul iple scle osis. Neu o adiology. May 18
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