A total of eighteen patients with shoulder pain were studied.
Standard and dynamic MR images were acquired using an 0.25 T open bore MRI scanner (Esaote S.p.A,
Before entering the scanner environment,
patients were explained and rehearsed the abduction movement they needed to perform.
Prior to the dynamic MR,
the standard MR images were acquired to report to the clinician the status of visible musculoskeletal structures.
On standard shoulder MR images twelve patients were diagnosed with supraspinatus tendonitis,
three with full-thickness and three with partial-thickness tear of the supraspinatus tendon.
The initial baseline position for the dynamic scanning was with elbow flexed in 90° and the hand placed unrestrained on the abdomen in neutral position.
A receiver coil was applied over the shoulder region.
Active and continuous abduction movement by patient was monitored by the technician,
who was counting from 0 to 20,
corresponding to 20 seconds.
This was to ensure that the patient understood when to start the movement and it helped to keep the pace relatively constant.
The positioning of the slice was aligned with the centre of the glenoid and humerus on the axial plane and with the distal part of the acromion on the sagittal plane.
The dynamic HYCE sequence was acquired in coronal plane with the following parameters of TR 7 msec; TE 3,5 msec; flip angle 70 degrees; 208x208 matrix; FOV 280x280 mm; slice thickness of 6 mm.
The degree of abduction varied from patient to patient depending on the factors,
such as size,
weight and intensity of pain during movements.
On average the maximum degree of abduction movement was around 60°.
DYNAMIC MR IN A HEALTHY VOLUNTEER
Three healthy subjects were scanned to standardize the final procedure,
movement and sequence for the DS-MR.
The example of the dynamic MR video is shown on Figure 1.
The relationship between the acromion and the humeral head during the movement is clearly visible.
During shoulder motion there is no evidence of impingement,
as the humeral head passes easily under acromion and the subacromial space is with normal and constant width during the whole movement cycle.
FULL THICKNESS OF THE SUPRASPINATUS TENDON (FT-SPS)
Full-thickness SPS tears are frequently associated with the reduction of the SAS.
The latter is illustrated in the example on Figure 2 with the evident reduction of the SAS during the baseline before initialising the movement and during the maximum abduction,
where the SAS is even more reduced.
Another patient with FT-SPS shows only slightly reduced SAS,
which stays fixed during the whole movement cycle (Figure 3).
PARTIAL THICKNESS TEAR OF THE SUPRASPINATUS TENDON (PT-SPS)
Partial thickness SPS tears may also result in reduced SAS that comes more apparent during the abduction movement (Patient 3,
Figures 4 and 5) or the SAS width is normal and will not show reduction during the abduction of the shoulder (Patient 4,
Figures 6 and 7).
SUPRASPINATUS TENDINOPATHY (SPS-T)
Patients with SPS tendinopathy have generally the width of the subacromial space within the normal limits.
We have noted in some SPS-T patients that the SAS stays with the same width during abduction movement (Patient 5,
Figures 8 and 9),
while in others the dynamic imaging exposes the reduced space between the acromion and the humeral head (Patient 6 and 7 on Figures 10 and 11).
QUANTITATIVE MEASUREMENTS OF THE SAS WIDTH DURING THE ABDUCTION MOVEMENT
The measures of the subacromial space were evaluated in all patients during baseline and in the maximal abduction movement.
On average the subacromial space was narrower in patients with full- and partial-thickness tears compared with patients with tendinopathy on baseline.
during abduction movement the tendency of the reduction of the width of the subacromial space was noted in some patients with SPS-T and PT-SPS,
but not in all patients.