This document discusses a study that used tagged magnetic resonance imaging (MRI) in the OsiriX platform to estimate myocardial torsion in the left ventricle. Tagged MRI was used to track motion over time by overlaying a grid pattern on the heart that deforms with cardiac motion. Researchers developed a plugin for OsiriX to segment the left ventricle boundaries and track motion between frames using harmonic phase flow imaging. They validated their method on data from 48 subjects, finding similar torsion trends but noisy results for some acquisitions. Future work will focus on quality indicators to improve reliability.

1. Albert Andaluz [CVC]
Francesc Carreras [CCB,HSP]
Cristina Santa-Marta [HGM]
Debora Gil [CVC]
Myocardial torsion estimation with
Tagged-MRI in the OsiriX platform
http://iam.cvc.uab.es
Tagged-MRI
Why torsion? Why Tagged-MRI? Why Osirix?
Myocardial torsion follows myocardial functionality Oversaturation overlays tags over material points "Designed by physicians for physicians"
Left Ventricle
+ = Dicom Viewer
Base Tag-grid deformation reflects intramural motion
Open Source
t=ref t=ref+1 t=ref+2
Apex AMT OsiriX [1]
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010101
010101 Image Processing
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(devcom icon (C) Devcom. http://www.devcom.com/)
Torsion estimation Validation
Boundary evolution PLUGIN: deployed at Sant Pau in September 2011
...
DOMAIN: manual segmentation of LV Boundaries at reference frame
PROTOCOL: different acquisitions, healthy and pathological cases
Source # Seqs Healthy? Modality Device
CCB 21 Yes SPAMM Siemens
HSP 8 No CSPAMM Philips
t=ref t=ref+1 t=ES CCB 12 No SPAMM Siemens
Harmonic Phase Flow HGM 7 No SPAMM Philips
MOTION : HPF ensures robust tracking wihout overestimating injured areas [2]
CHALLENGE: heterogeneous image quality
HGM CCB HSP
Validation
Base Apex
Scores
TORSION: difference in basal/mid and apex global rotation in the LV domain
degrees
8,0
6,0
io n
4,0 rs tion
To rota
ex
2,0 A p
0,0 %ES
Conclusions and future work
0,0
20
,0
40
,0
60
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,0 0,0 Similar torsion trends for SPAMM acquisitions.
10
-2,0
Base
rota C-SPAMM sequences too noisy for motion extraction.
tion
We will focus on quality indicators for improved reliability
References Affiliations
[1] Rosset, A., Spadola, L., Ratib, O.: Osirix: an open- source software for navigating in multidimensional dicom images. J Digit [CVC]: Computer Vision Center, UAB. Barcelona,Spain
Imaging 17(3) (Sep 2004) 205--16 [HSP]: Hospital de Sant Pau. Barcelona, Spain
[2] Carreras, F., Garcia-Barnes, J., Gil, D., et Al: Left ventricular torsion and longitudinal shortening: two fundamental components of [CCB]: Clinica Creu Blanca. Barcelona, Spain
myocardial mechanics assessed by tagged cine-mri in normal subjects. Int J Cardiovasc Imaging (Feb 2011) [HGM]: Hospital Gregorio Marañon, Dpt Física Matemática y de Fluidos, UNED.