Vikas Kundra, M.D., Ph.D. - Scbtmr...• WB-MR (T1 T2 P t) d 18MR (T1, T2, Post) and 18-F-FDG-PET/CT...

Whole Body MRBody MR

Vikas Kundra, M.D., Ph.D.

DisclosureDisclosure

• Nothing to discloseNothing to disclose• The work will describe non-FDA approved

MR sequencesMR sequences

WB-MR - AdvantagesWB MR Advantages• Whole body coverage• No radiation• Soft tissue and bone evaluation

• WB MR can be done in an hour or less– This commonly requires limiting sequences/planes

• Reading time is about the same as reading a PET/CT b t 15 20 iPET/CT – about 15-20 min.

• Can depict tumor expansion into adjacent paraosseous structures such as the spinal canalparaosseous structures, such as the spinal canal

• Applicable to many disease typesVikas Kundra, M.D., Ph.D.

WB-MR - DisadvantagesWB MR Disadvantages• May be limited for evaluation of the ribs and y

flat bone• More commonly done using a few planes andMore commonly done using a few planes and

sequences. This has the potential to limit sensitivity and specificity.sensitivity and specificity.

• Further evaluation of utility for assessing treatment response is neededtreatment response is needed.


WB-MR - Technical advancesWB MR Technical advances

• Parallel imaging Gl b l t i il t• Global matrix coil concepts

• High-field whole-body scanners• Moving table concept


WB-MR - DisadvantagesWB MR Disadvantages• Presently used primarily to assess bonesy p y

– Commonly limited sequences due to acquisition speed/total exam time

• Adding fat suppression increases time• Fat suppression field inhomogeneity or susceptibility

tif t ft i l fi ld f iartifacts often increase over large fields of view• Commonly based primarily on STIR now also DWI

– Commonly focused on boneCommonly focused on bone– Without other sequences, this may limit specificity

– Commonly limited planes– Commonly without Dynamic Imaging


WB-MR – What One S d Ch i D d hSees and Characterizes Depends on the

Techniqueq

• Bone• Soft tissue• Lymph nodes• Lymph nodes• Liver lesions


Example TechniquesExample Techniques

• T1T1• STIR• DWI• DWI

T2• T2• Contrast enhanced imaging

• Dynamic Imaging• Dixon-based “fat” and “water” imaging


WB MR for Bone Metastases(NSCLC and Malignant Melanoma)

WB MR (T1 T2 P t) d 18 F FDG PET/CT i l t• WB-MR (T1, T2, Post) and 18-F-FDG-PET/CT are equivalent

FDG-PET MRSens 45 64Spec 99 94PPV 54 83NPV 94 96Acc 94 91

• 1.5 T, Table steps, T1, FS Haste T2, Post contrast T1 Vibe

• 109 patients 11 with bone metastases (small number)• 109 patients, 11 with bone metastases (small number)• Eur J Radiol. 2009 Nov 26. [Epub ahead of print]


STIR – basic principalU i i t ll f tUses inversion recovery to null fat

180o ‐‐‐‐‐TI‐‐‐‐‐ 90o

FatTissue 1

‐‐‐‐‐TI‐‐‐‐

FatFluidMz

Time


RadioGraphics 2004; 24:1317–1330 Vikas Kundra, M.D., Ph.D.

WB MR for Bone MetastasesWB MR for Bone Metastases• WB-MR (T1, STIR) is superior to Bone Scan for detecting W ( , S ) s supe o o o e Sc o de ec g

bone metastases

BS MRSens 72 94Spec 75 90Acc 74 92

( )ROC 77 96 (P<.05) (P<.05)

• 1 5 T lli t bl ith 5 t ti T1 STIR 37 i t• 1.5 T, rolling table with 5 stations, T1, STIR, 37 minutes• Time to report, MR: 20 min, BS: 5 min• Author suggested limitation of WB MR: ribs and cranium

38 ti t 18 ith b t t• 38 patients, 18 with bone metastases

• Clin Radiol. 2010 Dec;65(12):989‐96. Epub 2010 Sep 27.Vikas Kundra, M.D., Ph.D.

Blood vesselsBlood vessels

er m

otio

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mot

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el diffusion

el diffusion

Sign

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gnal

Extracellular space Extracellular space -- cysts, gallbladder, etccysts, gallbladder, etcIntracellular spaceIntracellular spaceE ll lE ll l h ll lh ll l iiFa

ster

/long

eFa

ster

/long

em

acro

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Cellular leve

Cellular leve

Vikas Kundra, M.D., Ph.D.b valuesb values

5050Extracellular spaceExtracellular space-- hypercellularhypercellular tissuetissueFF (m(m CC

J Magn Reson Imaging. 2009 May;29(5):1154‐62. Vikas Kundra, M.D., Ph.D.

WB MR for Bone Metastases(Prostate or Breast Cancer)

• WB MR (DWI) similar to Bone Scan for• WB-MR (DWI) similar to Bone Scan for staging– subanalysisy

• WB-MR (DWI) = Bone Scan for detection if <5 lesions/patient

• WB-MR (DWI) > Bone Scan for detection if >10 ( )lesions/patient

• 1 5 T b-value=1000• 1.5 T, b-value 1000• Time to report, MR: 25min• 36 patients, 45 metastases and 107 benign lesions36 patients, 45 metastases and 107 benign lesions• Skeletal Radiol. 2010 Apr;39(4):333‐43.


WB MR (Multiplanar, Dixon-based Imaging)

• WB-MR (Multi-sequence, Multi-planar imaging)– Dixon-based

• Fat and water separation for “water only” and “fat only” images

• Including T1 + intravenous contrast• Including T1 + intravenous contrast• Including DWI• Including dynamic of the liver• No hardware modification need

• 1.5T• J Magn Reson Imaging. 2009 May;29(5):1154‐62.


WB MR - Dixon sequencesWB MR Dixon sequences• Two fast Dixon sequences:

– a fast spin echo triple echo Dixon (fTED) sequence (Ma J et al., Magn Reson Med 2007;58:103–109.)

• modified from the conventional FSE sequence – for T2‐weighted imaging

3D f il d di h d l h Di– 3D fast spoiled gradient echo dual echo Dixon (FSPGR‐DE) sequence (Ma J et al., MRI. J Magn Reson Imaging

2006;23:36 41 16)2006;23:36–41.16).• modified from the conventional 3D FSPGR sequence

– for T1‐weighted imaging

• J Magn Reson Imaging. 2009 May;29(5):1154‐62.Vikas Kundra, M.D., Ph.D.

WB MR - Dixon sequencesWB MR Dixon sequences• Two fast Dixon sequences:

difi i l i h f h i i l d– Modification ‐ replacing each of the original readout gradients with three (fTED) or two (3D FSPGR‐DE) readout gradients of alternating polarity to acquire three or two g g p y qraw images with water and fat signals having a relative phase shift of 0 and 180°.After removing the field inhomogeneity effects in– After removing the field inhomogeneity effects in postprocessing,

• raw images added or subtracted generating – water‐only,– fat‐only, and – Nonfatsuppressed images for each slice location

• J Magn Reson Imaging. 2009 May;29(5):1154‐62.


DIXON – basic principalS t “F t” d “W t ” Si lSeparate “Fat” and “Water” Signal

“Fluid”

“F ”“Fat”


WB – Dixon based Sequence Study Parameters

• 19 patients with known bone metastases from breast cancerbreast cancer

• 1.5 TM i t bl t h i• Moving table technique

• Body coil except for T1 and T2 weighted imaging of the chest abdomen and pelvis for which a torso phased array coil was used

• J Magn Reson Imaging. 2009 May;29(5):1154‐62.


Dixon‐based fTED (T2) Whole‐body MR

Coronal WB T2‐weighted fTEDT2 w/o fat sat “Water‐only” “fat only”

Ma J et al. JMRI 2009 Vikas Kundra, M.D., Ph.D.

Multisequence and Multiplanar WB MR

DWI Post Sag

Ma J et al. JMRI 2009 Vikas Kundra, M.D., Ph.D.

Dixon‐based 3D FSPGR (T1)+ dynamicy

Axial 3D FSPGR‐DE precontrastT1‐weighted Fat‐only Water‐only‐like fat sat T1

Arterial phase Portovenous phase Delayed phaseMa J et al. JMRI 2009 Vikas Kundra, M.D., Ph.D.

Sequence timeSequence acquisition Overall Patienttime table time

Total 46 min + 3 (SD) 69 + 5 (SD)(avg 3 readers)

Sequence time totalLocalizer :56Localizer :56DWI 3:43 x 6 stations 22:18FTED T2W Cor WB 10:15FTED T2W Cor WB 10:15 FSPGR DE T1W ax WB(+contrast 8:03 Triphasic ax abdomen 1:36

~23

Sag head and spine post 3:03

J Magn Reson Imaging. 2009 May;29(5):1154‐62.Vikas Kundra, M.D., Ph.D.

WB MR (Multiplanar Imaging)

Dixon‐based images

I Q lit F t iImage Quality Fat suppression uniformity

Average 3.4 + 0.5 3.4 + 0.5of 3 readers

Scale 0‐4, with 4 best

J Magn Reson Imaging. 2009 May;29(5):1154‐62.Vikas Kundra, M.D., Ph.D.


• 29 patients with known bone metastases from breast cancer

• Compared with bone scan• Divided skeleton into segments

– Counted up to 6 lesions per segment– Lesions scored as to confidence level for met 1-5 (highest)

G ld d d i /f i i di• Gold standard: prior/future imaging studies up to one year, biopsy when available

• Costelloe et al. J Magn Reson Imaging. In press



b i ( / )• 862 bone metastases on 29 patients (1-72/pt)Sensitivity Specificity

WB MR 70 8 89 1WB MR 70.8 89.1Bone Scan 59.6 98.7

P<.001 P<.001

• Lower specificity of WB MR thought to be due to availability of radiographs skeletal scintigraphy and CTavailability of radiographs, skeletal scintigraphy, and CT scans of the chest, abdomen, and pelvis being commonly available as gold standards, not MR, which would have higher resolutionhigher resolution.




• By trend,– Bone scan detected a

greater proportion ofgreater proportion of metastases in the head and ribs

– WB MR detected a– WB MR detected a greater proportion of metastases in the remainder of theremainder of the bones evaluated

• Costelloe et al. J Magn ResonImaging. In press



• Whole body MR also saw other lesions such asother lesions such as pleural effusions and liver metastases.metastases.

• Small lesion in the tibia not seen on bone scan isnot seen on bone scan is illustrated



Thank you


Vikas Kundra, M.D., Ph.D. - Scbtmr...• WB-MR (T1 T2 P t) d 18MR (T1, T2, Post) and 18-F-FDG-PET/CT...

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