Disclosures No financial disclosures Quantitative Evaluation of - - PowerPoint PPT Presentation

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Drew Lansdown, MD Lorenzo Nardo, MD Dmitrios Karampinos, PhD Julio Carballido-Gamio, PhD Thomas Link, MD Benjamin Ma, MD Roland Krug, PhD

Quantitative Evaluation of Fatty Infiltration of the Rotator Cuff Muscles with IDEAL Magnetic Resonance Imaging

Disclosures

• No financial disclosures

Background

• Rotator cuff tears account

for 4.5 million physician visits each year1

• 75,000 rotator cuff repairs

annually1

• May result in painful

shoulder with limited function

• 54% of asymptomatic

patients over age 60 have partial or full-thickness tear2

1. Oh, et al. CORR, 2007. 2. Reilly, et al. Ann R Coll Surg Eng, 2006

Fatty Infiltration and Muscle Atrophy

• Muscles of the rotator cuff undergo degenerative

changes after tendon injury1

– Fatty infiltration – Muscle atrophy

• Pathophysiology not fully understood1

– Decreased loading of muscle due to tendon injury – Traction injury to suprascapular nerve – Neoangiogenesis and metabolic changes

• Both are independent predictors of outcome after

surgical repair2

1. Chaudhury, et al. Arthritis Care & Research, 2012. 2. Gladstone, et al. AJSM, 2007.

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Goutallier Classification

• First described for CT and modified for MRI1,2
• Qualitative assessment
• Moderate inter-observer reliability (Κ = 0.53)3

Grade 0 Normal Grade 1 Streaks of fat Grade 2 More muscle than fat Grade 3 Equal muscle and fat Grade 4 More fat than muscle

1. Goutallier, et al. CORR, 1994. 2. Fuchs, et al. JSES, 1999. 3. Lippe, et al. Arthroscopy. 2012.

Clinical Relevance of Fatty Infiltration

• Cuff integrity after repair is directly related to

muscle quality1,2

– Re-tear rate is 50-70% with FI >= grade 2

• Unclear if these changes are reversible

– Goutallier - Possibly reverses in SS but not in IS – Gladstone – Minimal to no progression with successful repair

1. Goutallier, et al. CORR, 1994. 2. Gladtsone, et al. AJSM, 2007.

IDEAL MRI

• Iterative decomposition of

water and fat with echo asymmetry and least- squares estimation (IDEAL)

• Generates accurate

quantitative fat-fraction map

• Previous animal studies

validated fat content assessment with histologic studies1

• 1. Hines, et al. Radiology,2010.

Hypothesis

• IDEAL MRI fat fraction mapping provides a

continuous variable that is closely correlated with the Goutallier classification

• Fat fraction values are correlated with

strength testing from physical examination

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Study Design

• 57 patients undergoing

routine shoulder MRI

• IDEAL sequence added

to clinical study

• Goutallier grade given

for each rotator cuff muscle for each patient

• Range of motion and

pain levels (VAS) recorded from retrospective review of

• utpatient notes

Imaging Sequence Relevant Acquisition Parameters Purpose Sagittal PDW-FSE TR=2513 ms TE = 31 ms, rBW = 62.5 kHz, ETL = 10, NEX = 4 Goutallier classification Sagittal IDEAL- SPGR 6-points, TE=2.1 ms ∆TE=1.0 ms TR=10.8 ms, FA=3° rBW = 62.5 kHz, NEX=1 Fat quantification

Image Segmentation

• Segmented on sagittal-
• blique intermediate-

weighted FSE images

• Scapular “Y” identified

and a total of 4 slices were segmented

• Fat-fraction values were

calculated from the segmented regions using IDEAL fat fraction maps

Fat Fraction Values Correlate to Goutallier Classification

Goutallier Grade Mean Fat Fraction Value Range 2.1% (1.3%) 0 – 5.59% 1 5.6% (2.3%) 1.1-9.70% 2 8.5% (2.7%) 6.4 – 14.86% 3 16.2% (1.1%) 15.25 – 17.77% 4 24.7% (3.4%) 19.85 – 29.63%

Pearson’s correlation coefficient r = 0.93

IDEAL Values Have Good Intra/Inter-User Reliability

Supra Infra Subscap Teres Minor All muscles Intra- reproducibility Reader #1 0.96 0.84 0.92 0.96 0.92 Intra- reproducibility Reader #2 0.85 0.87 0.82 0.96 0.90 Inter- reproducibility 0.81 0.84 0.81 0.91 0.84

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IDEAL Values Correlate with Clinical Parameters

Muscles Spearman Rank Correlation-IDEAL Spearman Rank Correlation-GC Spearman p-values IDEAL Spearman p-values GC Supraspinatus Pain – VAS 0.128 0.012 0.3557 0.9318 FF Strength 0.206 0.032 0.1382 0.8215 Ab Strength 0.448 0.223

0.0011*

0.1201 Infraspinatus Pain – VAS 0.119 0.087 0.3910 0.5336 ER Strength 0.368 0.370

0.0067* 0.0064*

Subscapularis Pain – VAS 0.313 0.193

0.0214*

0.1625 IR Strength 0.39 0.30

0.0051* 0.0357*

Conclusions

• Fat fraction values are reproducible (κ = 0.81 –

0.96)and allow for a continuous variable for fat quantification

• Strength testing in supraspinatus,

infraspinatus and subscapularis are significantly correlated to IDEAL values

• IDEAL MRI can lead to improved evaluation

and understanding of fatty infiltration

Acknowledgements

• Benjamin Ma, MD
• Roland Krug, PhD
• Lorenzo Nardo, MD
• Dmitrios Karampinos, PhD
• Julio Carballido-Gamio, PhD
• Thomas Link, MD