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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5779_Библиотеки_им_академика_М_И_Перельмана
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10 Chapter 1
Many ultrasound machines have the ability to employ chroma tints, which allow for color-
coding of the grayscale image hues using a variety of colors, such as red, sepia, and others. Because
the human eye has greater ability to perceive different shades of color rather than various shades
of gray, use of chroma mapping allows for better visualization of subtler soft tissue details. In the
musculoskeletal system, this is most useful in the evaluation of soft tissue masses (eg, vascular
malformations, neuromas) and nerves (Figure 1-13).
10
A
Figure 1-13. Chroma tints. There is improved contrast resolution with decreased noise in this soft tissue mass (M)
using (A) chroma when compared with (B) grayscale.
B
Because ultrasound has a FOV, this limits evaluation of larger structures and their relationships
with the surrounding tissues. Extended FOV imaging allows the FOV to be enlarged by creating a
panoramic image. This is achieved by moving the transducer over the structure of interest with the
generation of multiple sequential images, which are combined to create the extended view without
loss of image quality (Figure 1-14).
Figure 1-14. Extended FOV imaging.
Allows for visualization of the entire
Achilles tendon (A) from the calcaneus
(CC) to the myotendinous junction
(MTJ).
3,11,12
Introduction to Musculoskeletal Ultrasound Imaging 11
DOPPLER IMAGING
The most commonly used forms of Doppler imaging are color and power. Doppler imaging
employs the concept of the Doppler effect, which describes the change in frequency of the sound
wave as the object (source) moves toward or away from the receiver (transducer). The amount of
the change in frequency is known as the Doppler shift. The amount of this shift is dictated by the
speed of the movement of the source. By measuring this change, the speed of the source can be
determined. The most common use of Doppler in musculoskeletal imaging is to determine the
presence of blood flow in the structure of interest, such as in a soft tissue mass, and occasionally
the direction or type of flow (eg, within vascular malformations).
Color-flow Doppler creates a 2-dimensional image superimposed on the grayscale image, where
information about the Doppler shift is assigned a color (red or blue) to indicate the direction of
flow (ie, blood flowing toward or away from the transducer, respectively). This technique does
not allow for the measurement of the velocity of blood flow (Figure 1-15).
power Doppler, results in the measurement of the strength of the Doppler signal emanating from
the sample volume of blood evaluated. The image is created in a similar manner to the color-flow
Doppler image, but instead assigns color based on the strength of the Doppler signal. Because the
power mode is more sensitive than conventional color Doppler, it can detect significantly lower
flow. Because detecting the mere presence of flow is generally more important in most musculoskeletal cases than assessing the direction of flow (unlike in abdominal imaging), power Doppler
is used more frequently (Figure 1-16). Power Doppler is also not subject to aliasing artifact, a result
of undersampling.
3,12,14
3,13
3,13
Another technique,
Figure 1-15. Color Doppler imaging.
Color Doppler image of a forearm
pseudoaneurysm demonstrates
blood flowing toward (red) and away
from (blue) the transducer.
A
B
Figure 1-16. Power Doppler imaging. (A) Grayscale and (B) power Doppler images of a metacarpophalangeal joint
demonstrating synovitis (Syn) with hyperemia (H). The increased sensitivity of power Doppler allows for detection
of low flow in small joints.
12 Chapter 1
Pulsed-wave or duplex Doppler allows for the measurement of the velocity of blood flow within
a single sample volume by using short pulses of sound waves as opposed to the continuous sound
waves generally used in standard Doppler ultrasound imaging. The information may then be displayed graphically as a spectral waveform.
3,12,13
REFERENCES
1. Hangiandreou NJ. AAPM/RSNA physics tutorial for residents. Topics in US: B-mode US: basic concepts and
new technolog y. Radiographics. 2003;23(4):1019-1033.
2. Jacobson JA. Fundamentals of Musculoskeletal Ultrasound. 3rd ed. Philadelphia, PA: Elsevier; 2018.
3. Gill R. The Physics and Technology of Diagnostic Ultrasound: A Practitioner’s Guide. Sydney, Australia: High
Frequency Publishing; 2012.
4. Martinoli C, Derchi LE, Pastorino C, Bertolotto M, Silvestri E. Analysis of echotexture of tendons with US.
Radiology. 1993;186(3):839-843.
5. Crass JR, van de Vegte GL, Harkavy LA. Tendon echogenicity: ex vivo study. Radiology. 1988;167(2):499-501.
6. Scanlan KA. Sonographic artifacts and their origins. AJR Am J Roentgenol. 1991;156(6):1267-1272.
7. Rubin JM, Adler RS, Bude RO, Fowlkes JB, Carson PL. Clean and dirty shadowing at US: a reappraisal.
Radiology. 1991;181(1):231-236.
8. Lin DC, Nazarian LN, O’Kane PL, McShane JM, Parker L, Merritt CR. Advantages of real-time spatial compound sonography of the musculoskeletal system versus conventional sonography. AJR Am J Roentgenol.
2002;179(6):1629-1631.
9. Strobel K, Zanetti M, Nag y L, Hodler J. Suspected rotator cuff lesions: tissue harmonic imaging versus conventional US of the shoulder. Radiology. 2004;230(1):243-249.
10. Sloves JM, Almeida JI, Sanchez Aguirre, PG, Abi-Chaker AM. Venous diagnostic tools. In: Almeida JI, ed. Atlas
of Endovascular Venous Surgery. 2nd ed. Philadelphia, PA: Elsevier; 2018:63-120.
11. Weng L, Tirumalai AP, Lowery CM, et al. US extended-field-of-view imaging technolog y. Radiology.
1997;2 03(3):877-880 .
12. Klauser AS, Peetrons P. Developments in musculoskeletal ultrasound and clinical applications. Skeletal Radiol.
2010;39(11):1061-1071.
13. Boote EJ. AAPM/RSNA physics tutorial for residents. Topics in US: Doppler US techniques: concepts of blood
flow detection and flow dynamics. Radiographics. 2003;23(5):1315-1327.
14. Bude RO, Rubin JM. Power Doppler sonography. Radiology. 1996;200(1):21-23.
2
Wrist and Hand
Mohini Rawat, DPT, MS, ECS, OCS, RMSK and Mukund Patel, MD, FACS
Contents
• Volar Wrist
Carpal Tunnel and Its Structures
º
Structures Outside the Carpal Tunnel
º
Volar-Radial Aspect of the Wrist
º
Volar-Ulnar Aspect of the Wrist
º
• Dorsal Wrist
Six Dorsal Compartments (Tendons From Radial to Ulnar Aspect)
º
• Distal Radioulnar Joint
• Scapholunate Ligament
• Triangular Fibrocartilage Complex
• Hand and Digits
Volar Aspect
º
Dorsal Aspect
º
Collateral Ligaments of Proximal Interphalangeal Joint
º
Ulnar and Radial Collateral Ligaments of First Metacarpophalangeal Joint
º
Hand Muscles and Associated Tendons
º
Carpometacarpal Joints
º
- 13 -
Atlas of Musculoskeletal Ultrasound of the E xtremities (pp 13-48).
Rawat M.
© 2021 SLACK Incorporated.
14 Chapter 2
VOLAR WRIST
Carpal Tunnel and Its Structures
Anatomy of the region is shown in Figure 2-1.
A
Figure 2-1. (A) Structures inside the carpal tunnel. The flexor retinaculum (grey) forms the roof of the carpal tunnel.
The median nerve (yellow) is the most superficial structure just beneath the flexor retinaculum. Flexor tendons lie
underneath the median nerve. The floor of the carpal tunnel is formed by carpal bones (brown). (conti nued)
Wrist and Hand 15
B
C
Figure2-1 (continued). (B) Cross-sectional anatomy at the proximal carpal tunnel. (C) Cross-sectional anatomy at the
distal carpal tunnel. (FCR = flexor carpi radialis; FPL = flexor pollicis longus; MN = median nerve; P = flexor digitorum
profundus tendons; S = flexor digitorum superficialis tendons.)
16 Chapter 2
1. Patient position: Sitting or in supine with wrist in full supination and resting on the table
2. Probe/transducer position:
a. Short axis (SX) view/transverse view: Use the pisiform as a bony landmark for the SX/
transverse view of the carpal tunnel.
b. Long axis (LX) view/longitudinal view: Once you locate the median nerve in the SX view,
keeping the nerve in focus, rotate the probe 90 degrees to see the LX view of the median
nerve (Figures 2-2 through 2-4).
A
B
C
Figure 2-2. (A) Probe placement for
the SX view of the median nerve. (B) SX
view of the carpal tunnel at the level
of the pisiform. (C) Labelled SX view
of the carpal tunnel at the level of the
pisiform. On the radial side: FCR outside
the carpal tunnel, FPL radial-most in
the carpal tunnel, flexor tendons (T)
in the carpal tunnel underneath the
median nerve (larger yellow circle). Outside the carpal tunnel on the ulnar side: ulnar nerve (smaller yellow circle) and
ulnar artery (red circle).
Wrist and Hand 17
A
B
Figure 2-3. (A) Probe placement for the LX view of the median nerve. (B) LX
view of the carpal tunnel: The median nerve appears as a hypoechoic band
overlying hyperechoic fibrillar flexor tendons.
A
Figure2- 4. (A) Proximal carpal tunnel anatomy and ultrasound image. (con tinued )
18 Chapter 2
B
Figure2-4 (continued). (B) Distal carpal tunnel anatomy and ultrasound image. The FCR can be seen deep in the
medial groove of the trapezium in its own compartment. (A = ulnar artery; MN = median nerve; P = flexor digitorum
profundus tendons; PL = palmaris longus; S = flexor digitorum superficialis tendons.)
Wrist and Hand 19
3. Relevant anatomy: From superficial to deep, structures in the carpal tunnel are arranged in
the order of skin, subcutaneous layer, flexor retinaculum (roof of the carpal tunnel), median
nerve, flexor tendons, and carpal bones (floor of the carpal tunnel).
4. Points to remember: A cross-sectional area of median nerve more than 10 mm
the pisiform is considered abnormal.
1
2
at the level of
Median nerve mobility in the carpal tunnel can be assessed with dynamic examination as
the patient flexes and extends the fingers and wrist. Median nerve mobility is negatively correlated with severity of the carpal tunnel syndrome.
2,3
Subsynovial connective tissue, which appears as a hypoechoic nonmoving layer surrounding the flexor tendons under the flexor retinaculum, is thicker in patients with carpal tunnel
syndrome than in normal healthy controls (Figure 2-5).
4,5
Figure 2-5. Subsynovial connective
tissue is a hypoechoic interface
(between cursors) bound by the
hyperechoic thin boundaries
between the nerve on top and flexor
tendons below.
Anomalies are common in the wrist. Some of the anomalies that may be present in wrist
scans are bifid median nerve, persistent median artery, anomalous muscle of forearm in
carpal tunnel (eg, flexor digitorum superficialis [FDS]), anomalous muscle of hand in carpal
tunnel (eg, lumbrical muscle), and reverse palmaris longus (rare).
6
Sonoelastography is a newer area in ultrasound where stiffness of the structure is assessed.
It has been reported that stiffness of the intracarpal tunnel structures in carpal tunnel syndrome is higher than in the healthy controls.
7
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