Patient characterization
29 pts: (11 female +18 male) with shoulder pain and disability underwent US with and without SE before MRI study.
18 cases involved the right side and 11 cases the left side.
17 cases involved the dominant arm and 12 cases the nondominant arm.
There were 6 full thickness rotator cuff tears,
9 partial thickness rotator cuff tears,
11 rotator cuff tendinopathy, 1 adhesive capsulitis, 2 calcific tendinitis.
Shoulder MRI protocol
MRI of the shoulder was reformed on GE Signa HDx 1.5 Tesla with a shoulder coil.
The MRI protocol included standard sequences for shoulder exams Fig. 2 .
3D reconstruction was added for the protocol for further Fusion navigation,
which was performed in 6 cases.
FD of the SSM was evaluated on the most lateral of the oblique sagittal T1-weighted images in which the scapular spine remained in contact with the scapular body.
The grade of fatty atrophy of the supraspinatus muscle belly was assessed according to Goutallier et al.
[5] classification Fig. 3
The severity of SS MA was achieved according to the Thomazeau [4] 3-point staging scale Fig. 4 The occupation ratio (R) of the SS fossa by the SS muscle belly was calculated on oblique sagittal T1 WI Fig. 1
Shoulder US protocol
Sonoelastography and US study were performed using:
•MyLab Class-C (ESAOTE) with a linear probe BL433 (3-18MHz)
US examination protocol performed with a standard technique according to Zanetti [7].
The muscle belly of the SSM was evaluated while the patient was asked to place his or her hand on the anterior ipsilateral thigh for the examination.
The transducer was perpendicular to the muscle belly of the SSM; this plane corresponded to the oblique sagittal MRI plane.
In order to obtain carefull evaluation of the occupational ratio of SSM to SS fossa Fusion US/MRI study was performed in 6 cases.
SE examination results were represented in color over the conventional B-mode image using the standardized settings,
recommended by manufacturer.
The SE images were obtained using mild compression; based on the quality factor.
The SE images are composed of 256 degrees color map,
which is configured such that the soft tissue is shown in yellow,
green and red and the hard tissue in blue.
US evaluation of SS MA and FD
The amount of FD was graded according to the modified Zanetti et al [7] 3-point grading scale based on the analysis of the echogenicity and echostructure of the SSM in comparance to the trapezius Fig. 5
The occupation ratio (R) of the SS fossa by the SSM belly was calculated on transverse US scan through the SS fossa Fig.
6
The amount of FD by SE was evaluated qualitatively based on the color differences between muscle and fat tissues with a modified 3-point grading scale previously described by Seo et al [8] Fig.
7
SS MA was evaluated using SE pattern as a mask above the grey scale image to increase visualization of the SSM.
Stiffness of the fat tissue is significantly lower than of the muscle.
Fat usually presented in yellow and red colors. These helped to delineate the border between the SSM and trapezius muscle which was of value for proper measurements Fig. 8 .
The severity of SS MA by US was achieved also according to the Thomazeau 3-point staging scale Fig. 4
Fusion US/MRI protocol
Fusion US/MRI was performed also on My LAB Class-C (ESAOTE) with a linear transducer BL433 (3-18MHz). Magnetic tracking sensor was placed over the US probe.
And a special electromagnetic transmitter placed near the patient which generated the magnetic field.
As recommended by the manufactures the main magnet was placed less than 70cm from the organ.
3D DICOM series of the shouder were loaded.
A apecial landmarks were choosed for Fusion.
This technique involves the co-registered display of live ultrasound with a reference series from 3D MRI.
The MRI image was displayed side-by-side with the live ultrasound Fig. 9
Statystical analysis
All data was compared to MRI for atrophy and FD.
The US and SE images were interpreted by two blinded observers using the measurement software of the PACS system (picture archiving and communication system).
The FD and MA was determined as a measurement of the grade determined by two blinded observers to evaluate interobserver reliability.
Spearman’s correlation coefficient was used to estimate the correlation of the SE images with the MR images and conventional US images.
Weighted kappa (j) coefficient was used to estimate the interobserver reliability in the evaluation of the SE images; an interobserver reliability was classified according to the kappa coefficients: ‘‘slight agreement’’,
0.00–0.20; ‘‘fair agreement’’,
0.21–0.40; ‘‘moderate agreement’’,
0.41–0.60; ‘‘substantial agreement’’,
0.61–0.80; ‘‘almost perfect agreement’’,
0.81–1.00.
The MRI grades of FD (0 and 1),
the US grade 0 and the SE grade 0 indicated ‘‘absence’’.
The FD grades 2,
3 and 4,
the US grades 1 and 2 and the SE grades 1 and 2 indicated ‘‘presence’ of FD’.