close

Вход

Забыли?

вход по аккаунту

?

958

код для вставкиСкачать
Pictorial Essay
Sonography of the Rotator Cuff and Biceps
Tendon: Technique, Normal Anatomy,
and Pathology
Lisa M. F. Thain, MD, FRCPC,1 Ronald S. Adler, PhD, MD2*
1
Department of Diagnostic Radiology, London Health Sciences Centre, University Campus, 339 Windermere
Road, London, Ontario N6A 5A5, Canada
2
Department of Radiology, University of Michigan Medical Center, 1500 East Medical Center Drive,
Ann Arbor, Michigan 48109-0030
Received 23 July 1998; accepted 28 April 1999
R
otator cuff sonography has a long learning
curve, but once mastered, it has over 93%
sensitivity and specificity for detecting partialand full-thickness tears.1 Sonography can detect
abnormal fluid or synovium, and it can dynamically assess acromial impingement on the supraspinatus tendon. Power Doppler imaging can
identify inflammation. This pictorial essay
presents the normal and abnormal sonographic
appearances of the rotator cuff and the long head
of the biceps tendon.
ANATOMY
The rotator cuff comprises 4 tendons: the teres
minor, infraspinatus, and supraspinatus tendons
insert on the greater tuberosity, while the subscapularis tendon inserts on the lesser tuberosity
(Figure 1). The long head of the biceps tendon
originates from the superior glenoid tubercle and/
or superior glenoid labrum. The biceps tendon
travels across the anterosuperior aspect of the
glenohumeral joint, through the rotator cuff interval (between the supraspinatus and subscapularis tendons), and down the humeral intertubercular groove. The biceps tendon is held in place by
the transverse humeral ligament and coracohumeral ligament and caudally by the humeral atCorrespondence to: L. M. F. Thain
*Present address: Department of Radiology and Nuclear
Medicine, The Hospital for Special Surgery, 535 East 70th
Street, New York, NY 10021-4828
© 1999 John Wiley & Sons, Inc.
446
CCC 0091-2751/99/080446-13
tachment of the pectoralis major tendon. A synovial sheath extends from the glenohumeral joint
and surrounds the proximal 3 cm of the biceps
tendon. The subacromial/subdeltoid (SASD)
bursa lies superficial to the rotator cuff and deep
to the deltoid muscle. A thin layer of fat surrounds the bursa, allowing its identification on
sonography.
TECHNIQUE
Sonography of the rotator cuff is performed using
a broad-band linear-array transducer of 5–10
MHz or multi-hertz transducer with variable center frequencies (eg, 8–13 MHz). Doppler capability is helpful. Extended-field-of-view technology
provides a single image of the abnormality in the
context of its regional anatomy.
The patient is placed in a series of positions to
allow optimal assessment of each tendon, the
joint capsule, and the SASD bursa. Each tendon
is assessed in the short and long axes and evaluated with power Doppler imaging for evidence of
increased flow, which indicates inflammation or
granulation tissue secondary to active repair.
Acromial impingement is assessed dynamically.
The long head of the biceps tendon is scanned
with the patient’s arm in neutral position, the
forearm resting on the patient’s lap with the palm
up (Figure 1A). The subscapularis tendon is
scanned with the patient’s arm at his or her side,
in external rotation. The infraspinatus tendon is
scanned with the patient’s arm across the front of
his or her chest, with the hand resting on the
JOURNAL OF CLINICAL ULTRASOUND
ROTATOR CUFF AND BICEPS TENDON
FIGURE 1. Anatomy and scanning planes for assessment of the rotator
cuff. (A) Anterior view of the right shoulder with the deltoid muscle
removed. The subacromial/subdeltoid (SASD) bursa is translucent to
allow visualization of the tendons deep to it. The SASD bursal fat is not
depicted on this drawing. Scan the subscapularis tendon and the long
head of the biceps tendons in the long axis, as shown by black bars
representing transducer footprints, and in the short axis by turning the
transducer 90°. (B) Posterior view of the right shoulder with the deltoid
muscle and SASD bursa removed. Scan the infraspinatus tendon in the
long axis with the transducer in the position shown. Scan in the short
axis by turning the transducer 90°. Scan the teres minor tendon by
moving the transducer inferiorly, and scan the glenohumeral joint by
moving the transducer medially. (C) Lateral view of the right shoulder
with the deltoid muscle, SASD bursa, and subscapularis tendon removed. Scan the supraspinatus tendon in the long axis, as shown, and
in the short axis by turning the transducer 90°.
VOL. 27, NO. 8, OCTOBER 1999
447
THAIN AND ADLER
opposite shoulder (Figure 1B). The teres minor
tendon is scanned in the same position, but the
transducer is moved inferiorly and slightly
obliquely to be parallel and then perpendicular
to the tendon’s fibers. The glenohumeral joint
is scanned by moving the transducer medially.
The supraspinatus tendon is scanned with the patient’s arm behind his or her back, with the hand
close to the opposite scapular tip (this brings
the supraspinatus tendon anterior to the acromion; Figure 1C). For each tendon, scanning continues laterally until the tendon ends on the greater
tuberosity. To test for impingement, the transducer is placed coronally with its medial margin
at the lateral margin of the acromion. The patient
abducts his or her arm while it is in internal rotation. The supraspinatus tendon should glide
easily under the acromion until the greater tuberosity nearly touches it. Next, the transducer is
placed sagittally with its posterior margin at the
anterior margin of the acromion. The patient
flexes his or her arm at the shoulder in internal
rotation to allow assessment of the supraspinatus
tendon for impingement in this position.
NORMAL SONOGRAPHIC APPEARANCES
The variably echogenic deltoid muscle lies deep to
the skin and subcutaneous tissues. The SASD
bursa lies deep to the deltoid muscle and superficial to the rotator cuff. Surrounding fat provides
a linear echogenic stripe on sonography. The rotator cuff lies deep to the SASD bursa. Tendons
are made of highly ordered bundles of collagen,
arranged in a linear parallel fashion, creating a
homogeneously echogenic fibrillar pattern on sonography (Figure 2). Tendons are most echogenic
when insonated at 90° relative to the surface of
the fibers, a property called anisotropy.2 If the
angle of insonation is not 90°, the bright specular
reflections are lost, and the echogenicity decreases, giving the impression of a tear.
The long head of the biceps tendon is visualized
most proximally at the rotator cuff interval. The
transverse ligament is an echogenic line lying superficial to the tendon and anchored to the
greater and lesser tuberosities. At least some of
the transverse ligament’s fibers are continuous
with those of the subscapularis tendon.
TENDON PATHOLOGY
Rotator Cuff Tears
Tendon tears are characterized sonographically
by focal discontinuity of fibers, either with inter448
posed fluid or with bursal herniation into the defect and loss of the convex margin of the tendon
(Figure 3). A secondary sign of tendon tear is increased echogenicity of the cartilage interface.
Tears can be partial or full thickness. A partialthickness rotator cuff tear can involve the humeral or the bursal surface. An intra-substance tear
usually extends from the insertion of the tendon
into its substance without exiting onto either the
humeral or bursal surface. A full-thickness tear
may involve some or all of the tendon width. In a
complete tear, the tendon tears across its entire
width, and the musculotendinous junction retracts.3 A massive tear is defined as a separation
of the tendon ends by more than 5 cm and involves more than 1 of the rotator cuff tendons.4
Sometimes, the debris in the gap is sufficiently
echogenic to mimic an intact tendon, in which
case the “cartilage interface sign” may be the only
clue to the tendon tear.
Tendinopathy
A diffusely hypoechoic tendon may indicate inflammation or fibrosis (Figure 4). Power Doppler
imaging can help to distinguish between these 2
entities (see below). Calcific tendinopathy causes
linear or globular brightly echogenic areas, usually with shadowing (Figure 4B). After rotator
cuff repair, the SASD bursal fat plane is often
missing (bursectomy). The tendon may be thinned
and irregular in contour with variable echogenicity (Figure 4C).
Biceps Tendon Dislocation and Tears
The long head of the biceps tendon may dislocate
medially, leaving an empty groove (Figure 5). A
ruptured biceps tendon results in the “empty
sheath sign,” with the echogenic transverse ligament resting against the concave intertubercular
groove and the tendon ends retracted proximally
and distally. Partial tendon tears are seen as focal
hypoechoic areas within the biceps tendon.
Fluid
A very small amount of fluid may lie in the glenohumeral joint and partially surround the biceps tendon. Abnormal amounts of fluid will
cause the capsule to bulge posteriorly (Figure 6A).
There is normally no perceptible fluid in the
SASD bursa. When fluid or synovial hypertrophy
is present, a hypoechoic space develops between
the rotator cuff and the deltoid muscle (Figures
6B and 6C). The combination of SASD bursal efJOURNAL OF CLINICAL ULTRASOUND
FIGURE 2. Normal sonographic appearances of the rotator cuff and biceps tendon. (A) Long-axis sonogram of
the right supraspinatus tendon (s). The tendon fibers are seen as echogenic lines. The Subacromial/Subdeltoid
bursal fat line (arrows) has a convex margin. a, acromion causing shadow; d, deltoid muscle; f, skin and
subcutaneous fat; g; greater tuberosity; h, humeral head; arrowhead, articular cartilage. (B) Short-axis sonogram of the right supraspinatus tendon (s) in the same patient. The tendon fibers are seen as echogenic dots.
The articular cartilage (arrowhead) is seen as a thin black band superficial to the humeral head (h) cortex.
There is a thin hypoechoic line between the tendon and the echogenic subacromial/subdeltoid bursal fat
(arrow). Anteriorly, there is signal drop-off due to anisotropy since the transducer is not 90° relative to these
fibers (curved arrow). (C) Short-axis sonogram of the right subscapularis tendon in the same patient. The
subscapularis tendon is multipenniform, with several tendon parts originating in the muscle and coalescing
into a single tendon just as it inserts on the lesser tuberosity. Consequently, short-axis images of the subscapularis tendons will show echogenic tendon “fingers” (arrows) interspersed with hypoechoic subscapularis muscle; this should not be misinterpreted as a tear. (D) Short-axis (left) and long-axis (right) sonograms
of the long head of the right biceps tendon in the intertubercular groove (arrows) in the same patient. The
tendon fibers appear in cross section as echogenic dots and in the long axis as echogenic lines just superficial
to the humeral cortex. The echogenic transverse humeral ligament (curved arrow) superficial to the biceps
tendon is attached to the greater (g) and lesser (l) tuberosities.
VOL. 27, NO. 8, OCTOBER 1999
449
THAIN AND ADLER
FIGURE 2. Continued. (E) Extended-field-of-view short-axis sonogram of the right supraspinatus tendon (s)
and the long head of the biceps tendon (b) at the rotator cuff interval (long arrow) in a different patient. This
image might be misinterpreted as showing a full-thickness tear of the supraspinatus tendon with a separate
fragment on the right side of the image. This “fragment” can be correctly identified as the biceps tendon by
turning the transducer 90° and demonstrating the biceps tendon in its long axis. Extended-field-of-view
technology provides the “big picture” with helpful landmarks. a, acromion; d, deltoid muscle; h, humeral
head; short arrows, subacromial/subdeltoid bursa. (F) Axial sonogram of the right glenohumeral joint posteriorly in the same patient as in A. The infraspinatus muscle (m) lies flat against the joint. There is no joint
effusion bulging out and displacing the muscle. g, posterior margin of glenoid; h, humeral head; arrows,
labrum.
450
JOURNAL OF CLINICAL ULTRASOUND
FIGURE 3. Tendon tears. (A) Long-axis (upper) and short-axis (lower) sonograms of the left supraspinatus tendon (s) with a partial-thickness
humeral surface tear (cursors) just proximal to the tendon’s insertion onto the greater tuberosity (g). There is mixed hypo- and hyperechoic
material in the gap between the fiber ends. Note the intact bursal surface fibers (arrowhead), which extend to the greater tuberosity, and the
echogenic subacromial/subdeltoid (SASD) bursal fat (arrow), which extends lateral to the greater tuberosity on the long-axis image. h, humeral
head. (B) Extended-field-of-view long-axis sonogram of the left supraspinatus tendon (s) in a different patient with a small full-thickness tear
(arrow) at the insertion onto the greater tuberosity (g). Note the fluid (arrowheads) in the SASD bursa, along the superior and lateral aspects of
the greater tuberosity. (C) Short-axis sonogram of the right supraspinatus tendon in a different patient with a full-thickness tear. Note fluid and
some debris interposed between the SASD bursal fat (arrow) and the articular cartilage (arrowheads), which appears echogenic relative to the fluid;
this is the “cartilage interface sign.” On other images, the fibers at the anterior edge (A) of the tendon were also torn. The posterior margin fibers
(P) remained intact along the entire tendon, making this an incomplete full-thickness tear. d, deltoid muscle; h, humeral head. (D) Short-axis (upper)
and long-axis (lower) sonograms of the left supraspinatus tendon (s) in a different patient with a full-thickness tear and bursal herniation into the
gap between the ends of the tendon. The contour of the SASD bursa (arrow) is concave, starting just proximal to the greater tuberosity (g) in the
long-axis image. The bursa (arrow) lies directly on the greater tuberosity in the short-axis image, with a few tendon fibers remaining intact at the
posterior margin of the tendon (s). (E) Sonogram obtained with the transducer in position for a short-axis image of the supraspinatus tendon in
a different patient. The tendon is completely torn and is not seen in this image. The deltoid muscle (d) is lying directly on the humeral head (h).
The articular cartilage (arrowheads) is hypoechoic relative to the SASD bursal fat (arrow). The infraspinatus tendon was also completely torn,
making this a massive rotator cuff tear.
THAIN AND ADLER
FIGURE 3. Continued.
fusion (> 2 mm thickness) and biceps tendon
sheath effusion (surrounding the tendon) has a
high (95%) positive predictive value for rotator
cuff tear.5
Impingement
The primary sign of impingement is visualization
of the supraspinatus tendon catching on or
bunching up lateral or anterior to the acromion
when the patient abducts or flexes his or her
shoulder in internal rotation (Figure 7).3 The
presence of bursal thickening without a history of
inflammatory arthropathy is a secondary sign of
impingement.5 Movement of SASD bursal material into the most lateral portion of the SASD
bursa with abduction provides further indirect
evidence of impingement.6
452
POWER DOPPLER IMAGING
Power Doppler imaging detects low-velocity microvascular (arteriolar and venular) flow and is
essentially angle-independent.7,8 Power Doppler
imaging depicts tissue hyperemia seen in inflammation or granulation tissue (secondary to repair). The pulse-repetition frequency and wall
filter levels used will vary and are machinedependent. The gain should be adjusted just until
there is no color in subcortical bone.
Normal tendons and synovial structures
around the shoulder show little if any flow on
power Doppler imaging. A branch of the anterior
humeral circumflex artery causes a focus of flow
along the long head of the biceps tendon. Power
Doppler imaging will demonstrate color signals in
the rotator cuff, SASD bursa, glenohumeral joint,
or biceps tendon of patients who have recently
JOURNAL OF CLINICAL ULTRASOUND
ROTATOR CUFF AND BICEPS TENDON
FIGURE 4. Rotator cuff tendinopathy. (A) Short-axis sonogram of the left supraspinatus tendon (s), which is
focally thickened and heterogeneous in echotexture. There may be a small intra-substance tear (curved arrow)
as well. Arrowheads, articular cartilage. (B) Long-axis sonogram of the right supraspinatus tendon (s) in a
different patient. There are coarse clumps of shadowing calcification (curved arrow) at the insertion, obscuring
the greater tuberosity. (C) Short-axis sonogram of the right supraspinatus tendon (arrows) in a different
patient 5 weeks after tendon repair and bursectomy. The tendon is thin and heterogeneous in echotexture,
with an irregular outline. Note the absence of the subacromial/subdeltoid bursal fat (arrowheads).
VOL. 27, NO. 8, OCTOBER 1999
453
THAIN AND ADLER
FIGURE 4. Continued.
FIGURE 5. Dislocation of the biceps tendon. Short-axis sonogram of the long head of the biceps tendon (b) dislocated from the intertubercular
groove (curved arrow) and lying superficial to the subscapularis tendon (t). This is an unusual dislocation because in most cases, the subscapularis
tendon’s attachment onto the lesser tuberosity (l) is also disrupted, allowing the biceps tendon to dislocate deep to the subscapularis tendon and
lie just superficial to the glenohumeral joint. In that situation, the subscapularis tendon would remain attached to the greater tuberosity (g) via its
continuity with the transverse humeral ligament.
454
JOURNAL OF CLINICAL ULTRASOUND
ROTATOR CUFF AND BICEPS TENDON
FIGURE 6. Abnormal fluid in the glenohumeral joint and subacromial/subdeltoid (SASD) bursa. (A) Axial sonogram of the posterior aspect of the
right glenohumeral joint with effusion (arrowheads), which is bulging the capsule and deforming the infraspinatus muscle (m). Arrow, posterior
margin of glenoid. (B) Coronal sonogram of an SASD bursal effusion lateral to the greater tuberosity (g) in a different patient. The bursa is
distended with hypertrophied synovium (arrowheads) and hypoechoic fluid. The bursal fat (arrows) is displaced by the effusion. S, supraspinatus
tendon, distal margin. (C) Short-axis sonogram of the right biceps tendon (BT) between the greater (g) and lesser (l) tuberosities in a different
patient with fluid in the SASD bursa (arrows) anterior to the tendon.
VOL. 27, NO. 8, OCTOBER 1999
455
THAIN AND ADLER
FIGURE 7. Acromial impingement on the supraspinatus tendon. (A) Long-axis sonogram of the right supraspinatus tendon (t) with the patient’s arm in internal rotation and adducted at his side. a, acromion; curved
arrow, subacromial/subdeltoid bursal fat. (B) Long-axis sonogram of the supraspinatus tendon (t) in the same
patient with the patient’s arm in internal rotation and abduction. Note that the tendon did not slide completely
under the acromion (a) but bunched up lateral to it, becoming thicker (#2 calipers). A tiny amount of fluid was
milked out into the lateral aspect of the subacromial/subdeltoid bursa (#1 calipers).
456
JOURNAL OF CLINICAL ULTRASOUND
ROTATOR CUFF AND BICEPS TENDON
FIGURE 8. Power Doppler sonograms of the rotator cuff and biceps tendon. (A) Short-axis sonogram of a
supraspinatus tendon (arrows) with tendinitis shows markedly increased flow (color). (B) Short-axis sonogram
of an enlarged biceps tendon (long arrow) in a different patient shows fluid in the sheath (short arrow) and
increased blood flow (color) both in and around the tendon. This is tenosynovitis and tendinitis.
undergone surgery or who have tendinitis or inflammatory arthropathy (Figure 8).
CONCLUSIONS
Sonography is readily available, noninvasive, and
relatively inexpensive. It can accurately diagnose
many of the common pathologic conditions of the
rotator cuff. In experienced hands, sonography is
more accurate for diagnosing rotator cuff abnormalities than is arthrography.1 Sonography is at
VOL. 27, NO. 8, OCTOBER 1999
least as sensitive and specific as MRI is, at lower
cost. Sonography provides a dynamic assessment
of acromial impingement, while power Doppler
imaging identifies any inflammatory component.
REFERENCES
1. van Holsbeeck M, Kolowich P, Eyler W, et al. Ultrasound depiction of partial-thickness tear of the rotator cuff. Radiology 1995;197:443.
457
THAIN AND ADLER
2. Fornage BD. The hypoechoic normal tendon—a pitfall. J Ultrasound Med 1987;6:19.
3. Thain LMF, Adler RS. Shoulder: rotator cuff and
long head of biceps tendons. In: Chhem RK, Cardinal E, editors. Guidelines and gamuts in musculoskeletal ultrasound. New York: Wiley-Liss; 1999. p.
56, 65.
4. Hawkins RJ, Bell RH, Lippitt SB. Atlas of shoulder
surgery. St. Louis: Mosby; 1996. p. 116.
5. Hollister MS, Mack LA, Patten RM, et al. Association of sonographically detected subacromial/
subdeltoid bursal effusion and intra-articular fluid
458
with rotator cuff tear. AJR Am J Roentgenol 1995;
165:605.
6. Farin PU, Jaroma H, Harju A, et al. Shoulder impingement syndrome: sonographic evaluation. Radiology 1990;176:845.
7. Newman JS, Adler RS, Bude RO, et al. Detection of
soft-tissue hyperemia: value of power Doppler sonography. AJR Am J Roentgenol 1994;163:385.
8. Dymling SO, Persson HW, Hertz CH. Measurement
of blood perfusion in tissue using Doppler ultrasound. Ultrasound Med Biol 1991;17:433.
JOURNAL OF CLINICAL ULTRASOUND
Документ
Категория
Без категории
Просмотров
7
Размер файла
3 206 Кб
Теги
958
1/--страниц
Пожаловаться на содержимое документа