Having recently acquired new scanners, we updated our MSK protocols and in so doing incorporated a lot of Dixon sequences in place of conventional PDFS (eg 3 planes Dixon PD in the knee). My reason for incorporating them was to have the ‘free’ FS and non-FS together and, in one of the planes, to include the out of phase for incidental marrow lesions. I have faced a few challenges/questions :
– Whilst it may not take longer, there’s more series on the PACS which can be annoying for those taking the MDT’s. Maybe this is just a ‘get used to it’ thing.
– Resolution. We don’t have an on-site MRI technical expert and I can’t help feeling the sequences aren’t as detailed as conventional PDFS on 3T. They look softer than the sharp high resolution PDFS I’m used to to. This may be filtering/smoothing and not Dixon’s fault.
– The tumour MDT folk have asked me if Dixon has any application in soft tissue/bone masses ie not just marrow? Other than the detection of fat, I can’t think of any.
– At the moment we’re sending through Out of phase, Water and In phase in one plane and just W and In in the others , We aren’t using Fat at the moment. What do people use Fat for?
Do some still use T2/PD FS and save Dixon for spine and known marrow issues? Or perhaps Dixon in one plane only?
My chief concern is to get the best possible resolution and also not be resented for the protocols because of clutter!
Your input would be greatly appreciated.
Kind fregards
Graeme
Dr Graeme Thompson
Consultant Musculoskeletal Radiologist
Oxford University Hospitals
Oxford Musculoskeletal Radiology
graemevthompson@gmail.com
Mobile: 07853396430
Office: 0800 170 1245
We heavily use Dixon in every protocol and find it incredibly useful.
When I started at UTSW- T1 CSI and later T1 Dixon was available- I got rid of T1W spin echo image and replaced with T1 Dixon immediately as it answered what T1W could tell us plus also provided marrow assessment.
In 2015 or so- T2 Dixon came around and we did a trial comparing it to PDW images, initially in the knee and then in other joints, replaced PD and PDFS with 3-plane T2 Dixons and used the saved times for 3D PD in all joints.
Recently, SMS T2 Dixon has become available, and our high-resolution knee protocol is 6 min with 3-plane T2 SMS Dixons and 3min 3DPDfs- so in less than 10 min-you get the best possible scan.
We also developed 3D Dixon at UTSW- but it is not a product yet (ref attached)- that will be ultimate imaging seq.
Tips-
* Can cut pd and pdfs and replace with 3-plane T2 Dixons- keep TE- 35-40ms, send only in-, opp, water maps- can also cut opp map in one or two planes, if too many images
* For axial planes of hip and shoulder- T2 dixon exhibits more motion- less so on siemens than Philips- so could use PD axial but I still like Dixon as it can d/d suppressed fat plus black lig or retinaculum on water image from the true ligament thickness on in-phase image
* Keep matrix high for sharpness
* Can use BLADE if motion
Advantages (see article)
* Short imaging time- 2min for fs and non fs contrast together
* Great fat suppression
* free marrow assessment (see article)- haven’t called a patient back in last 9 yrs for repeat CSI, etc.
* finding fracture in mound of edema (had a case today with path fx of sacrum and pubic bone- only seen on opp phase- astute fellow picked up in sacrum but didnt look at the pubic bone on opp phase- so missed that one)
* nerves/ligaments/cortical bone/cartilage- another nice look on opposed phase
* focal sclerosis- e.g. ulnocarpal abutment- you can see subchondral cyst on lunate but sclerosis of triq is often missed and only see on opp phase (had one case on mon in our county hosp, also in article attached)
* healing of myeloma and other lesions like in axial spondyloarthritis with fatty metamorphosis
* hemosiderin detection (sickle cell marrow, pvns, etc.)
* post-surgical scarring
* sarcoid granuloma detection (see article)
* Morphea scans (subQ sclerosis with scarring, loss of fat, fascial thickening, etc.)
*
ps articles below for your reading-
Sasiponganan C, Yan K, Pezeshk P, Xi Y, Chhabra A. Advanced MR imaging of bone marrow: quantification of signal alterations on T1-weighted Dixon and T2-weighted Dixon sequences in red marrow, yellow marrow, and pathologic marrow lesions. Skeletal Radiol. 2020 Apr;49(4):541-548. doi: 10.1007/s00256-019-03303-z. Epub 2019 Oct 12. PMID: 31606776.
Pezeshk P, Alian A, Chhabra A. Role of chemical shift and Dixon based techniques in musculoskeletal MR imaging. Eur J Radiol. 2017 Sep;94:93-100. doi: 10.1016/j.ejrad.2017.06.011. Epub 2017 Jun 16. PMID: 28655433.
Wang X, Harrison C, Mariappan YK, Gopalakrishnan K, Chhabra A, Lenkinski RE, Madhuranthakam AJ. MR Neurography of Brachial Plexus at 3.0 T with Robust Fat and Blood Suppression. Radiology. 2017 May;283(2):538-546. doi: 10.1148/radiol.2016152842. Epub 2016 Dec 22. PMID: 28005489.
Abbas LF, O’Brien JC, Goldman S, Pezeshk P, Chalian M, Chhabra A, Jacobe HT. A Cross-sectional Comparison of Magnetic Resonance Imaging Findings and Clinical Assessment in Patients With Morphea. JAMA Dermatol. 2020 May 1;156(5):590-592. doi: 10.1001/jamadermatol.2020.0036. PMID: 32236514; PMCID: PMC7113827.
Best!
AC
Avneesh Chhabra, M.D. M.B.A.
Professor Radiology & Orthopedic Surgery
Chief, Division of Musculoskeletal Radiology
UT Southwestern Medical Center, Dallas, Tx
5373 Harry Hines Blvd.
Dallas, Tx-75390-9178
Office: 214-648-2122
avneesh.chhabra@utsouthwestern.edu<mailto:avneesh.chhabra@utsouthwestern.edu>
http://www.utsouthwestern.edu<http://www.utsouthwestern.edu/>
________________________________
Sent: Tuesday, April 5, 2022 10:17 PM
will send
Avneesh Chhabra, M.D. M.B.A.
Professor Radiology & Orthopedic Surgery
Chief, Division of Musculoskeletal Radiology
UT Southwestern Medical Center, Dallas, Tx
5373 Harry Hines Blvd.
Dallas, Tx-75390-9178
Office: 214-648-2122
avneesh.chhabra@utsouthwestern.edu<mailto:avneesh.chhabra@utsouthwestern.edu>
http://www.utsouthwestern.edu<http://www.utsouthwestern.edu/>
________________________________
Sent: Tuesday, April 5, 2022 12:38 PM
EXTERNAL MAIL
Would be interested to hear what others say – especially Avneesh as I know he uses dixon a good bit
My understanding is that you can do a four point dixon with t2 weighting and use the same 20-35% drop out for benign red marrow while at the same time getting a fat only (like a T1 no fs) and fluid sensitive FS.
I also think you have the option of sending or not sending parts of the series as needed. So you could routinely send just in in or fat and water and then ask for all 4 as needed. This limits adding useless sequences.
One thing I noticed is a more homogenous FS than freq selective FS but it seemed more sensitive to motion and blurring. That was my resolution issue.
Anecdotally, we tried a lot of things to improve FS with brachial plexus cases and found stir with arms up to give best FS and resolution for sag. Don’t understand the physics behind the arms up being better. Dixon was too blurry for us with plexus.
Also the neurorads at Emory use dixon for spine – especially with pre and post. We recently had GE talk with us about FLEX which is their version of this. It seemed very useful especially for pre and post contrast fs in cases of pedal osteo.
Avneesh, hoping to hear you weigh in on this topic and applications if you have time as we are in the process of considering software updates and protocol changes.
Hi all
Having recently acquired new scanners, we updated our MSK protocols and in so doing incorporated a lot of Dixon sequences in place of conventional PDFS (eg 3 planes Dixon PD in the knee). My reason for incorporating them was to have the ‘free’ FS and non-FS together and, in one of the planes, to include the out of phase for incidental marrow lesions. I have faced a few challenges/questions :
– The tumour MDT folk have asked me if Dixon has any application in soft tissue/bone masses ie not just marrow? Other than the detection of fat, I can’t think of any.
– At the moment we’re sending through Out of phase, Water and In phase in one plane and just W and In in the others , We aren’t using Fat at the moment. What do people use Fat for?
Do some still use T2/PD FS and save Dixon for spine and known marrow issues? Or perhaps Dixon in one plane only?
My chief concern is to get the best possible resolution and also not be resented for the protocols because of clutter!
Your input would be greatly appreciated.
Kind fregards
Graeme
Dr Graeme Thompson
Consultant Musculoskeletal Radiologist
Oxford University Hospitals
Oxford Musculoskeletal Radiology
graemevthompson@gmail.com<mailto:graemevthompson@gmail.com>
Mobile: 07853396430
Office: 0800 170 1245
I have been training in Patrick Omoumi’s group and we have acquired quite some extensive experience with the Dixon technique, including with some validation papers (pls see list of ref. below, most of them are open access).
For a short overview of the many advantages, the first reference on the list is a good starting point and can easily be shared with trainees since it also covers the basics. It briefly mentions the current applications, including bone marrow imaging, oncology, whole body, as well as inflammatory disorders.
In our practice however, we find the Dixon technique less useful for joint imaging, in particular because:
– CHESS usually works better in these applications than with large field of view applications or imaging of extremities.
– Dixon sequences are intrinsically longer than your conventional sequences, and in joints, spatial resolution is important, so there is less room for compromise than for spine imaging for example.
I’m happy to answer more specific questions if helfpul.
Cheers,
Fabio
CHUV – Centre Hospitalier Universitaire Vaudois6 18 27
Dr méd. Fabio ZANCHI, Chef de clinique
Unité d’imagerie ostéo-articulaire
Service de radiodiagnostic et radiologie interventionnelle
CHUV – Rue du Bugnon 46 -1011 Lausanne<oweb.chuv.ch/owa/redir.aspx?C=UfJdaDBXZTMcDC_ps29ehnvjHICH9SiBJp8EPRKGXm63kMZUNcTUCA..&URL=https%3a%2f%2foweb.chuv.ch%2fowa%2fUrlBlockedError.aspx>
Mobile +41 (0)79 55
List of references:
The Dixon method in musculoskeletal MRI: from fat-sensitive to fat-specific imaging.<pubmed.ncbi.nlm.nih.gov/34928411/> Omoumi P. Skeletal Radiol. 2021 Dec 20. doi: 10.1007/s00256-021-03950-1.
Differentiation between benign and malignant vertebral compression fractures using qualitative and quantitative analysis of a single fast spin echo T2-weighted Dixon sequence.<pubmed.ncbi.nlm.nih.gov/34041569/> Bacher S, Hajdu SD, Maeder Y, Dunet V, Hilbert T, Omoumi P. Eur Radiol. 2021 Dec;31(12):9418-9427. doi: 10.1007/s00330-021-07947-1. Epub 2021 May 26. PMID: 34041569; PMCID: PMC8589814.
MRI of non-specific low back pain and/or lumbar radiculopathy: do we need T1 when using a sagittal T2-weighted Dixon sequence?<pubmed.ncbi.nlm.nih.gov/32020402/> Zanchi F, Richard R, Hussami M, Monier A, Knebel JF, Omoumi P. Eur Radiol. 2020 May;30(5):2583-2593.
Improved contrast for myeloma focal lesions with T2-weighted Dixon images compared to T1-weighted images.<pubmed.ncbi.nlm.nih.gov/31130374/> Danner A, Brumpt E, Alilet M, Tio G, Omoumi P, Aubry S. Diagn Interv Imaging. 2019 Sep;100(9):513-519.
Bone Marrow Metastases: T2-weighted Dixon Spin-Echo Fat Images Can Replace T1-weighted Spin-Echo Images.<pubmed.ncbi.nlm.nih.gov/29095674/> Maeder Y, Dunet V, Richard R, Becce F, Omoumi P. Radiology. 2018 Mar;286(3):948-959.
Fat Suppression with Dixon Techniques in Musculoskeletal Magnetic Resonance Imaging: A Pictorial Review.<pubmed.ncbi.nlm.nih.gov/26583362/> Guerini H, Omoumi P, Guichoux F, Vuillemin V, Morvan G, Zins M, Thevenin F, Drape JL. Semin Musculoskelet Radiol. 2015 Sep;19(4):335-47.
________________________________
De : ocad-msk@googlegroups.com <ocad-msk@googlegroups.com> de la part de Graeme Thompson <graemevthompson@gmail.com>
Envoyé : mardi, 5 avril 2022 09:20
À : OCAD_MSK
Objet : Place of DIXON in current protocols
Hi all
Having recently acquired new scanners, we updated our MSK protocols and in so doing incorporated a lot of Dixon sequences in place of conventional PDFS (eg 3 planes Dixon PD in the knee). My reason for incorporating them was to have the ‘free’ FS and non-FS together and, in one of the planes, to include the out of phase for incidental marrow lesions. I have faced a few challenges/questions :
– The tumour MDT folk have asked me if Dixon has any application in soft tissue/bone masses ie not just marrow? Other than the detection of fat, I can’t think of any.
– At the moment we’re sending through Out of phase, Water and In phase in one plane and just W and In in the others , We aren’t using Fat at the moment. What do people use Fat for?
Do some still use T2/PD FS and save Dixon for spine and known marrow issues? Or perhaps Dixon in one plane only?
My chief concern is to get the best possible resolution and also not be resented for the protocols because of clutter!
Your input would be greatly appreciated.
Kind fregards
Graeme
Dr Graeme Thompson
Consultant Musculoskeletal Radiologist
Oxford University Hospitals
Oxford Musculoskeletal Radiology
graemevthompson@gmail.com<mailto:graemevthompson@gmail.com>
Mobile: 07853396430
Office: 0800 170 1245
My approach will be to use it but only in one plane for most joints.
Kind regards
Graeme
Dr Graeme Thompson
Consultant Musculoskeletal Radiologist
Oxford University Hospitals
Oxford Musculoskeletal Radiology
graemevthompson@gmail.com
Mobile: 07853396430
Office: 0800 170 1245
[gallery]
Just finished a talk for residents at UTSW.
See attached some examples of T2 Dixon and 3D PD/PDFS pertinent to this discussion.
Happy Wednesday!
My Dad always says- do new things or share on wed- budh is shubh in hindi- means Wed is auspicious!
Start Dixons and 3D on wed if you havent’t! You won’t miss any findings and shall pick up much more..
Best!
AC
Avneesh Chhabra, M.D. M.B.A.
Professor Radiology & Orthopedic Surgery
Chief, Division of Musculoskeletal Radiology
UT Southwestern Medical Center, Dallas, Tx
5373 Harry Hines Blvd.
Dallas, Tx-75390-9178
Office: 214-648-2122
avneesh.chhabra@utsouthwestern.edu<mailto:avneesh.chhabra@utsouthwestern.edu>
http://www.utsouthwestern.edu<http://www.utsouthwestern.edu/>
________________________________
Sent: Wednesday, April 6, 2022 12:13 PM
Cc: ASM <adamsinger82@gmail.com>; OCAD-MSK <ocad-msk@googlegroups.com>
Thanks to everyone who gave such detailed feedback. It seems to me there are a lot of benefits to Dixon but using it in the joints requires optimisation of the sequence parameters. In a facility with limited tech support this takes some work.
My approach will be to use it but only in one plane for most joints.
Kind regards
Graeme
Dr Graeme Thompson
Consultant Musculoskeletal Radiologist
Oxford University Hospitals
Oxford Musculoskeletal Radiology
graemevthompson@gmail.com<mailto:graemevthompson@gmail.com>
Mobile: 07853396430
Office: 0800 170 1245
Hello,
We heavily use Dixon in every protocol and find it incredibly useful.
When I started at UTSW- T1 CSI and later T1 Dixon was available- I got rid of T1W spin echo image and replaced with T1 Dixon immediately as it answered what T1W could tell us plus also provided marrow assessment.
In 2015 or so- T2 Dixon came around and we did a trial comparing it to PDW images, initially in the knee and then in other joints, replaced PD and PDFS with 3-plane T2 Dixons and used the saved times for 3D PD in all joints.
Recently, SMS T2 Dixon has become available, and our high-resolution knee protocol is 6 min with 3-plane T2 SMS Dixons and 3min 3DPDfs- so in less than 10 min-you get the best possible scan.
We also developed 3D Dixon at UTSW- but it is not a product yet (ref attached)- that will be ultimate imaging seq.
Tips-
* Can cut pd and pdfs and replace with 3-plane T2 Dixons- keep TE- 35-40ms, send only in-, opp, water maps- can also cut opp map in one or two planes, if too many images
* For axial planes of hip and shoulder- T2 dixon exhibits more motion- less so on siemens than Philips- so could use PD axial but I still like Dixon as it can d/d suppressed fat plus black lig or retinaculum on water image from the true ligament thickness on in-phase image
* Keep matrix high for sharpness
* Can use BLADE if motion
Advantages (see article)
* Short imaging time- 2min for fs and non fs contrast together
* Great fat suppression
* free marrow assessment (see article)- haven’t called a patient back in last 9 yrs for repeat CSI, etc.
* finding fracture in mound of edema (had a case today with path fx of sacrum and pubic bone- only seen on opp phase- astute fellow picked up in sacrum but didnt look at the pubic bone on opp phase- so missed that one)
* nerves/ligaments/cortical bone/cartilage- another nice look on opposed phase
* focal sclerosis- e.g. ulnocarpal abutment- you can see subchondral cyst on lunate but sclerosis of triq is often missed and only see on opp phase (had one case on mon in our county hosp, also in article attached)
* healing of myeloma and other lesions like in axial spondyloarthritis with fatty metamorphosis
* hemosiderin detection (sickle cell marrow, pvns, etc.)
* post-surgical scarring
* sarcoid granuloma detection (see article)
* Morphea scans (subQ sclerosis with scarring, loss of fat, fascial thickening, etc.)
*
ps articles below for your reading-
Sasiponganan C, Yan K, Pezeshk P, Xi Y, Chhabra A. Advanced MR imaging of bone marrow: quantification of signal alterations on T1-weighted Dixon and T2-weighted Dixon sequences in red marrow, yellow marrow, and pathologic marrow lesions. Skeletal Radiol. 2020 Apr;49(4):541-548. doi: 10.1007/s00256-019-03303-z. Epub 2019 Oct 12. PMID: 31606776.
Pezeshk P, Alian A, Chhabra A. Role of chemical shift and Dixon based techniques in musculoskeletal MR imaging. Eur J Radiol. 2017 Sep;94:93-100. doi: 10.1016/j.ejrad.2017.06.011. Epub 2017 Jun 16. PMID: 28655433.
Wang X, Harrison C, Mariappan YK, Gopalakrishnan K, Chhabra A, Lenkinski RE, Madhuranthakam AJ. MR Neurography of Brachial Plexus at 3.0 T with Robust Fat and Blood Suppression. Radiology. 2017 May;283(2):538-546. doi: 10.1148/radiol.2016152842. Epub 2016 Dec 22. PMID: 28005489.
Abbas LF, O’Brien JC, Goldman S, Pezeshk P, Chalian M, Chhabra A, Jacobe HT. A Cross-sectional Comparison of Magnetic Resonance Imaging Findings and Clinical Assessment in Patients With Morphea. JAMA Dermatol. 2020 May 1;156(5):590-592. doi: 10.1001/jamadermatol.2020.0036. PMID: 32236514; PMCID: PMC7113827.
Best!
AC
Avneesh Chhabra, M.D. M.B.A.
Professor Radiology & Orthopedic Surgery
Chief, Division of Musculoskeletal Radiology
UT Southwestern Medical Center, Dallas, Tx
5373 Harry Hines Blvd.
Dallas, Tx-75390-9178
Office: 214-648-2122
avneesh.chhabra@utsouthwestern.edu<mailto:avneesh.chhabra@utsouthwestern.edu>
http://www.utsouthwestern.edu<http://www.utsouthwestern.edu/>
________________________________
Sent: Tuesday, April 5, 2022 10:17 PM
will send
Avneesh Chhabra, M.D. M.B.A.
Professor Radiology & Orthopedic Surgery
Chief, Division of Musculoskeletal Radiology
UT Southwestern Medical Center, Dallas, Tx
5373 Harry Hines Blvd.
Dallas, Tx-75390-9178
Office: 214-648-2122
avneesh.chhabra@utsouthwestern.edu<mailto:avneesh.chhabra@utsouthwestern.edu>
http://www.utsouthwestern.edu<http://www.utsouthwestern.edu/>
________________________________
Sent: Tuesday, April 5, 2022 12:38 PM
EXTERNAL MAIL
Would be interested to hear what others say – especially Avneesh as I know he uses dixon a good bit
My understanding is that you can do a four point dixon with t2 weighting and use the same 20-35% drop out for benign red marrow while at the same time getting a fat only (like a T1 no fs) and fluid sensitive FS.
I also think you have the option of sending or not sending parts of the series as needed. So you could routinely send just in in or fat and water and then ask for all 4 as needed. This limits adding useless sequences.
One thing I noticed is a more homogenous FS than freq selective FS but it seemed more sensitive to motion and blurring. That was my resolution issue.
Anecdotally, we tried a lot of things to improve FS with brachial plexus cases and found stir with arms up to give best FS and resolution for sag. Don’t understand the physics behind the arms up being better. Dixon was too blurry for us with plexus.
Also the neurorads at Emory use dixon for spine – especially with pre and post. We recently had GE talk with us about FLEX which is their version of this. It seemed very useful especially for pre and post contrast fs in cases of pedal osteo.
Avneesh, hoping to hear you weigh in on this topic and applications if you have time as we are in the process of considering software updates and protocol changes.
Hi all
Having recently acquired new scanners, we updated our MSK protocols and in so doing incorporated a lot of Dixon sequences in place of conventional PDFS (eg 3 planes Dixon PD in the knee). My reason for incorporating them was to have the ‘free’ FS and non-FS together and, in one of the planes, to include the out of phase for incidental marrow lesions. I have faced a few challenges/questions :
– The tumour MDT folk have asked me if Dixon has any application in soft tissue/bone masses ie not just marrow? Other than the detection of fat, I can’t think of any.
– At the moment we’re sending through Out of phase, Water and In phase in one plane and just W and In in the others , We aren’t using Fat at the moment. What do people use Fat for?
Do some still use T2/PD FS and save Dixon for spine and known marrow issues? Or perhaps Dixon in one plane only?
My chief concern is to get the best possible resolution and also not be resented for the protocols because of clutter!
Your input would be greatly appreciated.
Kind fregards
Graeme
Dr Graeme Thompson
Consultant Musculoskeletal Radiologist
Oxford University Hospitals
Oxford Musculoskeletal Radiology
graemevthompson@gmail.com<mailto:graemevthompson@gmail.com>
Mobile: 07853396430
Office: 0800 170 1245