|
|
  |
| ||
 Image1: Ultrasound of the shoulder (tenosynovitis of the biceps tendon) |
Many diseases of the bony skeleton first arise in the soft tissues which are optimally imaged with high frequency ultrasound scans. State of the art muskuloskeletal ultrasound imaging requires frequencies at least 5 MHz and specially designed and focussed linear array transducers. The small anatomic wrist, shoulder as well as ankle and foot structures and superficial locations are best examined with probes over 10 MHz in frequency. The higher the scanning frequency, the poorer the sound penetration. This results in improved resolution, but the loss of distal information may occur when scanning deeper structures. Linear probes, as contrasted with sector scanners,, better outline the course of tendons which are most often aligned in straight paths. Also, sector scanners produce bright echoes at the center of the image and fewer echoes at the periphery. A standoff pad may sometimes be used to insonate the subcutaneous structures. Comparison with the opposite side is possible and usually helpful in diagnosis. Cysts or fluid filled areas are without internal echoes and are called echo free. Solid regions have internal echoes and are classified as echo poor or hypoechoic if there are few internal echoes. The term echogenic or hyperechoic is used if there are many internal echoes. The skin of the foot appears highly echogenic as do the bony structures. Bone, air, foreign bodies and calcification stop the transmission of sound waves producing a "sonic shadow" which is a dark region distal to the echogenic obstructing region. The term acoustical shadowing is also used to describe the low or absent echoes associated with these lesions. Acoustic window refers to an optimal placing of the transducers so that the areas of interest are clearly imaged. | ||
  |
|
As with any imaging modality, transverse and longitudinal scans or any set of orthogonal planes is acquired to produce a three dimensional representation of abnormalities. Sonography is a dynamic study permitting physiologic real time observation of an anatomic region. Subluxations of peroneal tendons may be diagnosed dynamically. Unlike, CT and MRI, metal prostheses and post surgical metallic clips do not prove a major hindrance since alternative scan planes may be used to look around these devices. The magic angle effect noted in curving tendons is not present. Haziness from vaguely increased signal due to the specific MRI partial volume effect of the surrounding fat is common in the peroneal tendons. In particular, the partial volume effect of the cortical bone of the malleolus may make imaging of the more anteriorly located peroneus brevis more difficult. Likewise, the dark bands of
MRI signal-less retinaculae may be inseparable from tendon with MRI, although the retinaculum is an echogenic structure with ultrasound and readily separable during scanning. Similarly, peritendineum of the Achilles tendon that appears as an echo poor or echo free space on sonography, cannot be distinguished on the MRI scan as a distinct structure. Intra-articular loose bodies have various MRI signals. Mature marrow fat will have high signal. Heavily calcified bodies are often dark on all imaging sequences. Chondral and soft tissue areas often have intermediate signals. Ultrasound distinguished easily between calficic and non calcific regions due to the bright signals produced by the highly reflective calcium and bony entity. Errors due to MRI and CT positioning may also be avoided by sonography. For example, a low lying belly of the muscular peroneus brevis so that it lies within the fibular groove is said increase the risk of peroneus brevis tendon rupture or dislocation. A recent report shows that this anatomic occurrence may occur in dorsiflexion of the foot during examination. The dynamic nature of sonograms often prevents misinterpretation due to anatomic positioning. Additionally, sonography by its real time dynamic nature permits full length imaging of the posterior tibial tendon, peroneal tendons and fibulocalcaneal ligament which are difficult to visualize in total course by standard MRI sequences and planes.
The so called MRI "Gold Standard" apparently underestimates the degree of tendon damage and nerve root inflammation when compared to high resolution ultrasound with power doppler. However, use of ultra high frequency probes limits penetration of the sound beam. Examination of a pathologically enlarged Achilles tendon with a 12-15 MHz probe may result in poor penetration of the sound waves to the deeper pre-Achilles fat pad, the bursae subtendinea and the tricipitis surae muscle. Likewise, a lower extremity that is edematous due to lymphedema, heart failure and similar etiologies of limb swelling could limit tendon imaging. In these cases, MRI examination would provide better anatomic detail. MRI also affords a panoramic view which is easier to the surgeon to utilize. The deeper structures, or, superficial regions that lie deep to the skin surface due to overlying edema, tumor or hematoma, may be imaged with lower frequency transducers offering greater penetration of the sound beams. Imaging from the side that is closer to the structure of interest is also possible to avoid degradation of the high frequency images due to excessive distance parameters.
The examiner should look for normal variants and other pathological processes associated with any abnormal finding. For example, in tears of the peroneus brevis tendon, ruptures of the lateral collateral ligaments, stripping of the superior peroneal retinaculum, peroneal longus subluxations and low lying muscle bellies of the peroneus brevis and peroneus quartus may be concomitantly identified. Bony pathologies such as abnormally curved surfaces or osteophytes and avulsion type micro fractures may similarly be discovered. Patient comfort is another important consideration that makes sonograms preferable as a diagnostic procedure. Infants or uncooperative patients may be accurately scanned with real time units providing instantaneous data. Indeed, children may be held in their mother's arms. If necessary, portable
equipment may be brought to the bedside or nursing home. since scan times with low strength MRI units may exceed half an hour, the rapidity of ultrasound examination for the elderly provides a significant positive patient compliance factor. Claustrophobia does not occur as a problem either. other imaging methods are cited here for completeness. Tenography technique is highly examiner dependent and is so specialized that it does not fall within the scope of this. Light scanning, also known as fiber optic transillumination or diaphanography. |
 |
|
Normal Anatomy
The imaged anatomy of normal tendons depends on the frequency and angulation of the transducer applied to the structure. The probes from 5-10 MHz usually show internal linear echogenic bands regularly alternating with echo poor areas within the tendon while higher frequency probes (11-20 MHz) will demonstrate many more and thinner echogenic band like regions. These correspond to the parallel alignment of the regularly arranged collagen fiber bundles. Angulation of the probe to a oblique incidence of the sound beam will cause the tendon to lose the internal echogenic stepladder architecture and appear echo free in certain cases and is due to the normal anisotropic nature of sound in tendon. This seeming artifact is used to diagnostic advantage when looking at pathology that may simulate a tendon. The absence of disappearance of internal echoes during angulation maneuvers suggests that the structure is other than tendinous in nature. Rotator Cuff The tendons of the rotator cuff may demonstrate tears that are incomplete and non surgical or complete and thus in need of surgical attention. Ultrasound is more accurate than MRI in this area. Calcific tendonitis may also be documented. Carpal Tunnel
Achilles Tendon The Achilles tendon is a confluence of the individual tendons of the gastrocnemius and the soleus muscles. In the ankle, the tendon lies immediately beneath the skin and subcutaneous tissues. The most common variety of formation is two thirds from the gastrocnemius and one third from the soleus. The fibers twist about 6 cm proximal to the calcaneal insertion which is also a hypovascular region, accounting for the majority of ruptures at this anatomic site. The anteroposterior diameter of the tendon in normal males is less than 6.9 mm and less than 5.2 mm in normal females. The distal surface is flat to slightly concave anteriorly, although the distal tendon near its calcaneal insertion assumes a more ovoid and anteriorly flattened shape assuming a width that is twice the size of the anteroposterior diameter. The edges are rounded and the tendon is 10-15 cm in length. The muscle fibers at the musculotendinous junction appear linear and hypoechoic and must be distinguished from a tear. Dorsal to the tendon is the hypoechoic Kager's fat. Deeper yet is the flexor hallucis longus muscle. Pathology in both these structures may be elicited at the time of examination of the Achilles tendon. The patient is scanned prone with the feet hanging over the table edge. Dynamic dorsal and plantar flexion positioning are performed. The diagnosis of tendon rupture is easily made by ultrasound, usually with the tear located at the level of the posterior malleolus and the defect in the echogenic tendon filled with anechoic blood or fluid. Retraction of the proximal and distal edges may be better observed during dorsiflexion and plantar flexion maneuvers. Longitudinal partial tears may be imaged similarly and the presence of peritendon fluid or Achilles bursal fluid documented. Chronic tears may lose the tendon fluid interface and even the disrupted tendons may be quite difficult to image. Tendonitis is diagnosed when the distance between the tendon bundles increased and there is a 2 mm increase in anteroposterior diameter of the entire tendon as compared to the normal contra lateral side. Xanthomas of the Achilles tendon is the most characteristic location for heterozygous familial hypercholesterolemia. This appears as a speckled or reticulated pattern within the tendon although focal nodules are also found. Due to the exquisite sensitivity of ultrasonic findings, it has been suggested that sonography be part of the work up of suspected patients. Although there is no tendon sheath, fluid may be found in the adjacent bursae. A finding associated with both tendonitis and tears is increased echogenicity of the subjacent fat pad. This is due to decreased tissue or increased fluid in the region of the normal tendon allowing better sonic penetration. Healing of the tendon may be followed by serial ultrasound scans. The differential diagnosis of accessory soleus muscle may be easily made due to the characteristic appearance of the muscle fibers in the supracalcaneal region. Posterior Tibial Tendon The posterior tibial muscle tendon junction arises several centimeters above the medial malleolus. It then turns under the malleolus to fan out in its insertion on the navicular, cuneiforms and bases of the second through fourth metatarsal bones. The normal supramalleolar tendon is hyperechoic and oval shaped having an anteroposterior diameter from 4-6 mm. At the level of the medial malleolus, the average tendon diameters are 7.8 x 3.7 mm. A thin hypoechoic tendon sheath surrounds the tendon and may contain a thin layer of fluid. The posterior tibial tendon usually tears longitudinally and demonstrates an internal cleft oriented in a cephalocaudal direction. Associated swelling of the tendon is noted and the presence of transverse tears must be evaluated and look similar to Achilles tendon tears with the ruptured tendon straddling the hematoma. In transverse scanning, the supramalleolar groove will appear empty. In longitudinal images, the ruptured ends may have a wavy fibrillar appearance that results from absence of tendon tension. In chronic and late stage injuries, fluid may be absent and the retracted tendon ends may be sonographically invisible. MRI examination of this tendon has difficulty distinguishing between tendonitis and early tendon rupture. Tenosynovitis of this tendon presents with hypoechoic features and enlargement. The hypoechoic rim of the peritendon fluid is larger than the contra lateral side. This appears as a target sign in cross section with the echogenic centrally located tendon surrounded by the echo poor or echo free fluid. Irregularity of the tendon contour may be noted. A technical reminder that the flexor digitorum longus may simulate a normal posterior tibial tendon in the longitudinal scan plane. This error is identified by careful correlative imaging in the transverse plane. Peroneal Tendons The peroneus longus tendon arises from the tibia, fibula head and intermuscular septum. The peroneus brevis tendon originates from the lower fibula and intermuscular septum somewhat anteriorly to the longus and both are bound in their common synovial sheath by a fibrous superior and inferior retinacula. The peroneal tendons lie in a tunnel that is formed by the malleolus in front, the superior peroneal retinaculum posteriorly and laterally, and the posterior talofibular and calcaneofibular ligaments medially. Distal to the malleolus the@peroneus brevis and longus tendons diverge and have separate tendon sheaths.
The peroneal tendons are almost round in transverse scans and nearly equal in size. A tendon sheath is present for both although may be larger in the peroneus longus. Small amounts of fluid are seen in asymptomatic patients. Large volumes or proximally located fluid is considered abnormal. The normal peroneus quartus tendon and/or muscle lies medial to the peroneus longus tendon. It should not be confused with splitting type deformity of the peroneus brevis tendon. Hypertrophy of the peroneus longus may be noted in conjunction with hypertrophy of the peroneal tubercle and appears with the normal striated echo pattern and increased in size. Like the posterior tibial tendon, ultrasound may differentiate between intrasubstance tears and full thickness ruptures. The peroneal tendons usually tear in a longitudinal plane. Tears of the longitudinal type usually center at the retromalleolar groove in the case of the peroneus brevis tendon and show a
characteristic wrapping around the peroneus longus tendon. In one series of peroneus brevis tears there was a 29% incidence of concomitant tears in the peroneus longus tendon. Peroneal tenosynovitis accompanies rupture of the superior peroneal retinaculum with associated subluxation of the peroneal brevis and longus tendons out of the bony groove behind the lateral malleolus. Partial loss of congruity between the tendons and the peroneal groove is termed subluxation and appears as lateral location of the tendon with respect to the lateral margin of the fibula. Lateral malleolar bursitis or a lateral malleolar ganglion cyst must not be mistaken for peroneal tendon disease. |
 |
The anterior tibiofibular ligament is imaged as a echogenic band between the tibia and fibula and is evaluated by scanning anteriorly. Also noted at this time is the anterior tibiotalar recess and the echo poor hyaline cartilage covering the talar dome. Lateral scanning at the malleolus demonstrates the echogenic anterior tibiofibular and calcaneofibular ligaments. Posterior transverse approach shows the posterior tibiofibular ligament to best advantage since it is short and horizontal. It has been suggested that sonography may be more accurate than non contrast MRI due to the complex orientations of ligaments. The normal ligament has a similar ultrasound appearance to normal tendon substance. Trauma usually produces a hematoma in the space of the disrupted ligament which appears as an echo free region. In the case of the ruptured anterior tibiofibular ligament, stress on the syndesmosis may be measured ultrasonically and the degree of widening evaluated. After a week echo poor granulation may be noted to fill the gap in the distracted ligament. Partial tears may show as echo free clefts paralleling the ligamentous fiber orientation.
|
 |
Dynamic study of the heel and ankle for diagnosis of synovial pathology of the fluid or proliferative variety includes searching for bursal fluid and abnormalities of the adjacent tendons, articular cartilage and juxtaarticular bone. Use of power Doppler aids in differentiating solid synovial hypertrophy from simple fluid collections and is covered separately at the end of the chapter. Chronic untreated bursitis may appear solid on MRI. In tenosynovitis, the complete disappearance of peritendon echo poor areas during compression signifies that fluid was present as opposed to pannus or thickened synovial membrane. Careful search for intratendinous rheumatoid nodules as well as areas of rupture of the peroneal and posterior tibial tendons must be performed. Synovial cysts may be simply diagnosed by ultrasound. Ganglia and their possible communication with a joint or tendon sheath may be evaluated. Synovitis in rheumatoid arthritis occurs commonly in the anterior recess and may be difficult to distinguish from fluid. Rheumatoid nodules are a vasculitis that destroys by contact with
adjacent structures. Power Doppler shows increased flow in active synovitis and active nodules and has proven valuable in separating synovial fluid from active pannus and nodules.
The tibiotalar joint is best evaluated in the longitudinal scan plane with the foot in plantar flexion. Post traumatic fluid collections are echo free and usually resolve within a month following injury. Since the presence of joint fluid is a natural ultrasonic window for evaluation of intraarticular lesions, small loose bodies may be readily identified as the examiner presses alternately on the lateral and medial joint recesses. Ultrasound is considered the most appropriate modality for diagnosing loose bodies in the ankle joint. Unlike MRI, debris within fluid may be classified as to calcific or soft tissue. Calcific foci produce bright echoes on perpendicular scanning that cast sonic shadows in appropriate planes. Soft tissue debris parallels the specific pathology as to echo poor or echogenic entities, without the bright specular reflectors and sonic shadow signs. Free air or gaseous media within a fluid filled joint will also cast a sonic shadow with bright echoes, however, this may be diagnosed by plain film radiographs and ultrasonic compression techniques. Another entity capable of producing ankle symptoms and pathologic findings is the Baker's cyst of the popliteal fossa associated with rheumatoid arthritis. As the cyst becomes distended with fluid and synovial proliferation it may extend distally into the ankle. Baker's cysts developing in the framework of rheumatoid athropathy are characterized by internal echoes within the fluid and marked irregularity of the synovium. Ultrasonically, this manifests as echogenic fluid with irregular internal walls of medium amplitude echoes. The power Doppler feature of the ultrasound unit will detect increased flows in the active pannus. Tenosynovitis with increased tendon echogenicity is an anomaly found with inflamed tendons within large fluid collections. The usual inflamed tendon is echo poor and enlarged. However, the pathologic tendon that is surrounded by water type medium will show higher echogenicity than expected due to the greatly increased sound penetration in fluid. If possible, scanning the tendon in a path that avoids the fluid region will produce more useful information, thus avoiding the false impression of normal tendon echogenicity. Compression maneuvers that disperse the fluid away from the site under investigation may also be useful in deciding the true echogenicity of a tendon.
|
 |
Normal muscle bundles are hypoechoic and separated by well ordered symmetrical hyperechoic bands of fibroadipose septae. Hypertrophy, atrophy and variations from normal are imaged. Muscle anomalies, such as the accessory soleus muscle, appear as normal muscular striations within the echo poor background. Trauma is the most common muscular traumatic condition in the lower extremity. Muscles are best examined during rest and during contraction. Comparison with the contra lateral side is often helpful. Direct trauma usually crushes muscle adjacent to
underlying bone whereas indirect trauma stretches the muscle beyond its normal limit. The most commonly injured muscle is the medial gastrocnemius due to jumping during athletic sports. Strains produce no visible alteration of the normal oblique parallel echogenic straie. Contusions have a variety of appearances depending on the degree of focal fluid collection and the time course. Indeed, the only finding may be enlargement in the anteroposterior diameter of the muscle. Partial rupture shows disruption of the homogeneous striations and the presence of extra cellular fluid. The gastrocnemius frequently demonstrates a detachment of the lower end of the medialis muscle fibers from the common aponeurosis of the triceps surae. Partial ruptures are shown to better advantage during the contraction phase. Complete rupture appears as a hypoechoic hematoma with the retracted ends of the muscle noted as echogenic fragments at the border of the fluid collection, occasionally appearing as a bell clapper configuration. Early healing shows an infusion of echogenic vessels at the periphery, which is later serially followed to complete resolution. This influx of neovascularity produces a blizzard like picture which may mimic the snow storm appearance of ruptured silicone prostheses and may be differentiated by power Doppler exam which literally shows the neovascularity in the healing region cystic lesions, fibrous scars, myositis ossificans and hernias (especially of the tibialis anterior muscle) are sequellae of incomplete healing. Fibrous scars are initially echo poor and later become echogenic. Dynamic sonography may be used to document the functional damage caused by adhesions and permanent scarring.
|
 |
Sonograms of peripheral nerves have become commonplace in the last few years with high frequency transducers. At 5 MHz imaging, the normal nerve fibers appear echo poor. The honey combed internal structure is strikingly apparent at 10-15 MHz as the structure shows an echo free background with linear echogenic fibrils internally similar to those found in tendon although more widely spaced in longitudinal or axial scanning. This presents a stippled pattern in cross section. This feature is used in documenting the digital nerve entering a neuroma or Morton's type lesion. Inflamed nerves appear echo poor and show flow patterns on power Doppler interrogation. True nerve tumors appear echo free at 7-10 MHz but fill in with fine echoes at higher frequency ranges. Sonography can only be completely reliable when the tumor and the junction of the nerve of origin are simultaneously documented.
|
 |
|
Ganglia Ganglia commonly found around the ankle and dorsum of the foot are typically anechoic. The examiner may search for a neck that may enter the adjacent joint space. Aspiration may be performed under ultrasound guidance. Inflammation and infection due to foreign bodies may be diagnosed and fistulous tracts may be identified. Ultrasound may be used to guide the removal of non radio-opaque objects such as wooden splinters, tooth picks, plastic or glass fragments and cactus spines. Morton's Neuroma Morton's neuroma is a fibrosing process occurring in and around the plantar digital nerve. Fibrosis on sonography is echo poor in character. The transducer is first placed transversely over the plantar region of the metatarsal heads. Any hypoechoic mass is then scanned longitudinally along the axis of the digital nerve to show a connection Size of this lesion may be serially followed by sonography. Improved imaging of this disorder occurs when the examiner pushes with a finger on the dorsal web space as compression is used on the plantar positioned transducer. True plantar neuromas are composed of neural tissue and are usually echo free simulating fluid due to the high homogeneity of the structure. Dynamic imaging by pressure shows true fluid to change shape whereas compression of the tumor will cause no alteration in appearance. There is an alignment with the hypoechoic nerve demonstrable as well. Plantar Fasciitis The normal plantar fascia is homogeneously echogenic measuring between 2-4 mm in normal patients with no difference in thickness between males and females. The plantar fascia is scanned transversely for overall integrity and geometry. It is then imaged longitudinally to show the total length of the fascia and its insertion site. The edges of the plantar fascia are imaged as parallel smoothly echogenic lines. The structure within is noted to be one of fine parallel echogenic lines reflecting its fibrillar organization. The thickness tends to be homogeneous along its entire length. Plantar fasciitis syndrome is characterized by heel pain at the insertion of the plantar fascia onto the medial tubercle of the calcaneus. Plantar fasciitis is noted by thickening of the structure as well as hypoechoic transformation of the area. This process may be focal or diffuse. Interruption of the fascia due to partial or complete tearing may be appreciated. In one study, the maximal thickening occurred approximately 2 cm from the calcaneal insertion site. Peri-insertion edema has also been reported. De novo fluid collections may sometimes be identified. Ultrasound diagnosis is important, since the appearance of plantar calcaneal spurs has no direct relation to heel pain. Plantar fibromas appear as hypoechoic nodules with a heterogeneous echo pattern. Tarsal Tunnel Syndrome The neurovascular bundles of the tarsal tunnel contents are fixated by fibrous septae. Traction disorders or compression from mass lesions readily produce sensory symptoms. Ultrasonography may show a ganglion as an echo free focal well circumscribed cystic region whereas free fluid will conform more to the anatomy of the adjacent tarsal tunnel. Peripheral nerve sheath tumors and neurilemmonas are usually hypoechoic and lie in the plane of the nerve structure. Hemangiomas have various echo patterns and are thus not easily diagnosed. Indeed, Doppler flows may be high or low in these masses. Dilated or varicose veins have a worm like appearance. Doppler flows are quite clear as is compression venous reflux. Fibrous scars are typically echo poor and are adjacently inseparable to other anatomic structures. Hypertrophy of the abductor hallucis muscle or accessory abductor hallucis muscle appears as typical echogenic linear muscle striations and will pose no diagnostic difficulty. Tenosynovitis with effusion or synovial hypertrophy may be well evaluated. Various post traumatic causes may be noted depending on the type of pathology involved. Whereas most disorders of the tarsal tunnel are identifiable by ultrasound, pathologies of the sinus tarsi, especially of the bifurcated ligament, can only be studied by MRI. 
|
 |
Only 15% of wooden fragments are seen on plain film x-rays. Sutures, plastic and small glass pieces are similarly difficult to identify radiographically. Ultrasound quickly images these echogenic structures either by their bright reflections or by the associated acoustic shadowing that occurs when sound transmission is blocked. Indeed, intraoperative transducers are commercially available to localized and remove foreign bodies such as thorns and cactus needles that may hide along fascial planes. The often associated inflammatory response may be distinguished as an echo free region of fluid or echo poor abscess focus that typically forms a halo around the foreign body. Metal objects have a specific comet tail artifact that is recognizable as a series of bright echoes trailing the initial bright echo. Skin lesions, free subcutaneous air, sesamoid bones, postinflamatory, post traumatic and bursal calcifications all cast acoustic shadows.
|
 |
Conventional pulsed and continuous wave Doppler exams are
used to demonstrate blood flow. However, these are time consuming and relatively insensitive. Color Doppler uses computer coding to demonstrate directional blood flows in a clinically useful manner. Power Doppler is a new feature of blood flow analysis that is proportional to the total number of moving scatterers. This allows low flow states and minute vascular structures to be imaged. Potential clinical applications are the neovascular regions found in healing fractures, resolving hematomas, inflammatory tenosynovitis, acute gouty inflammation, and distinguishing synovial fluid from vascular synovium. Gouty arthritis demonstrates the highest vascular power Doppler response and active rheumatoid synovitis is next in line closely followed by the new callus of fracture healing. Evaluation of arterial and venous malformations is possible by power Doppler's high
sensitivity. Abnormal pulsatility may be noted in a non vascular region during routine scanning. Arterial occlusive disease is best examined by color Doppler and pulsed wave ultrasound since power Doppler is non directional. Venous insufficiency is best studied with color Doppler and pulsed wave sonography as well for similar reasons.
|
 |
The oldest, fastest and certainly the least expensive study used for centuries is light scanning. The non invasive procedure of transillumination, clinically used for breast disease evaluation and diagnosis of scrotal pathology, shows great promise in evaluating injuries. Potentially important is the role of light scanning, the current term for transillumination, in the diagnosis of the nature and extent of muscle rupture and tendon injury. Although light scanning has been used for breast cancer detection for over fifty years and scrotal hydrocele analysis for many years, its usage in musculoskeletal injury is relatively new while seemingly quite logical. Light absorption of the transilluminated area is compared with the contra lateral side or with adjacent normal tissue architecture and adjusted for differences in depth. Early usage called the test "diaphanography" and required photographic picture acquisition and visual observation. Today's interpretation is often made with a radiographic sensitometer or a low light level closed circuit television monitor. While not widely appreciated, it may be used to narrow the focus of other imaging modalities to a specific region and would be of particular use in the younger pediatric population.
Minor trauma to a muscle belly may be accompanied by serous fluid extravasation. If this process is localized, light scanning will be unremarkable. If the leakage is accompanied by hemorrhage, light absorption will be noted since the deoxygenated hemoglobin in the hematoma dramatically blocks light transmission due to absorption in proportion to the hematomal's size and borders and is compared with the unaffected normal contra lateral side. It is important to realize that calcification or bone do not affect the absorption of the optical transmission in the way that x-rays are absorbed by calcium. A long standing serous leakage may become secondarily infected, thus producing unilateral light absorption. Thus, trauma, blunt or penetrating, may be associated with bleeding or products of tissue inflammation that absorb light rays. Thus, normal symmetric transillumination may suggest the probability of structural intactness of the muscle. Medium degrees of transmission blockage are associated with structural failure of the muscle and massive light absorption loss accompanies hemorrhage and/or infection in the muscle or its associated traumatic seroma. The tendon may be examined with simultaneous fiberoptic light scanning. Light scanning showed intratendinous hematomas greater than 1 mm. Resolution of this may be followed with this modality. Indications for transillumination are cyst diagnosis and suspected bleeding or a suspicious lesion not clearly defined by MRI or ultrasound.
Certain inflammatory conditions such as peri-tendon exudates were imaged well by transillumination.
|
 |
For many years ultrasound guidance of needle localization for masses and fine needle aspiration biopsy has been preferred to radiographic localization both for its accuracy and speed.
Therapeutic considerations of ultrasound guidance of focal injections into muscular structures, inflamed joints, fascial planes and tendon sheaths is feasible. Dynamic muscle testing will show decreased mobility around areas of fibrous scarring as well as absence of change and size of muscle tissue. Since needling and injection infiltration is considered the most effective modality for immediate relief of pain and complete removal of pathology causing pain, this could be performed under ultrasound guidance to promote optimal healing in muscular ankle injuries. Indeed, cavitation ultrasound or electrocautery of peripheral tumors may be feasible.
|
 |
|
1. Bard R Ultrasound of the Ankle in Disorders of the rear foot. Ranawat, C Editor Churchill Livingstone New York 1997 2. Neuhold A, Sitskal M, Kainberger F et al Degenerative Achilles tendon disease: assessment by magnetic resonance and ultrasonography Eur J Radiol 14: 213, 1992 3. Mink JH, Reicher MA, Crues JV, Deutsche AL MRI of the Knee Raven Press New York 1993 4. Rademaker J, Rosenberg ZS, Beltran J et al Alterations in the distal extension of the musculus peroneus brevis with foot movement AJR 168: 787, 1997 5. Maldjian C, Mezgarzadeh M, Roach NA et al Efficacy of 3-dimensional FSE MRI of the ankle AJR 168 No 3: 25, 1997 6. Habra G, van Holsbeeck M Tendon pathology: Multimodality imaging AJR 168 No 3: 205, 1997 7. Cucin R, Bard R: False Positive Mammographic Imaging of a Breast Implant New York State J Medicine 93: 151-152, 1993 8. Gunderson J, Nilsson D, Ohlsson B: Diaphanography for Assessment of Mammary Changes Lakartidningen 76: 1425-1429, 1979 9. Bard R: Multimodality Imaging The Female Patient17: 11, 1996 10. Bard R: Light scanning of tendon injury Presented at Sixth Annual Conference on Musculoskeletal Ultrasound Montreal 1996 11. van Holsbeeck M, Introcaso JH Musculoskeletal Ultrasound Mosby St.Louis 1991 12. Bureau N, Roederer G Achilles tendon xanthoma: ultrasound vs. MRI Presented at Sixth Annual Conference on Musculoskeletal Ultrasound Montreal 1996 13. Cheung Y, Rosenberg ZS, Magee T et al Normal anatomy and pathologic conditions of ankle tendons: current imaging techniques. Radiographics 12:429, 1992 14. Hsu T, Wang C, Wang T et al Ultrasonographic examination of the posterior tibial tendon Foot and Ankle International: 18:34, 1997 15. Rosenberg Z, Feldman F, Singson R Peroneal tendon injuries: CT analysis Radiology 161: 743, 1986 16. Rosenberg ZS, Beltran J, Cheung YY et al MR f eatures of longitudinal tears of the peroneus brevis tendon AJR 168:141, 1997 17. Chhem RK, Beauregard G Synovial diseases p.47 in Musculoskeletal Ultrasound Fornage BD editor Churchill Livingstone New York 1995 18. Hamilton WG, Geppert MI, Thompson FM Pain in the posterior apsect of the ankle in dancers J.Bone and Joint Surg. 78: 1491, 1996 19. Marcelis S, Daenen B, Ferrara MA Peripheral Musculoskeletal Ultrasound Atlas p. 162 Thieme New York 1996 20. Zeiss J, Coombs RJ, Booth RL etal Chronic bursitis presenting as a mass in the pes anserine bursae:MR diagnosis J Comput Assist Tomogr 17:137, 1993 21. Adler R Power Doppler applications in musculoskeletal ultrasound Presented at 6th Annual Conference of Musculoskeletal Ultrasound Montreal 1996 22. Marcelis S, Daenen B, Ferrara MA Peripheral Miisculoskeletal Ultrasound Atlas p.172 Thieme New York 1996 23. Bard R The blizzard sign of intramuscular healing hematoma Presented at 6th Annual Conference of Musculoskeletal Ultrasound Montreal 1996 24. Letho A, Alanen A Healing of a muscle trauma: correlation of sonographical and histological findings of an experimental study in rats J Ultrasound Med 6: 425, 1987 25. Solbiati L, Rizzato G Ultrasound of superficial structures Churchill, Livingstone New York 1995 p.324 26. Fornage BD Sonography of peripheral nerves of the extremities Radiol Med 85: 162, 1993 27. Redd RA, Peters VJ, Emery SF et al Morton,s neuroma: Sonographic appearance Radiology 171: 415 1989 28. Singer K and Jones D Soft tissue conditions of the ankle and foot in The lower extremity in sports medicine, p. 498, J Nicholas and E Hershman, Editors, CV Mosby St Louis 1986 29. Frey C, Shereff M, Tendon injuries about the ankle in athletes Clin Sport Med 7:103, 1988 30. Wall RW, Harkness MA, Crawford A, Ultrasound diagnosis of plantar fasciitis Foot and Ankle 14: 465, 1993 31. Gibbon WW, Plantar fasciitis Radiology 182: 285, 1992 32. Gooding GAW, Hardiman T, Sumers M etal Sonography of the hand and foot in foreign body detection J Ultrasound Med 6: 441, 1987 33. Fornage B, Touche DH, Segal P etal Ultrasonography in the evaluation of muscular trauma AJR 134: 375 1980 34. Fischer A Local injections in pain management Phys Med Rehab Clin N Am 6: 851, 1995 35.Mullen V: Whiplash Injury J Musculoskeletal Med 14:71, 1997 36.Bard R, Garde R: Ultrasonography of Adult Spinal Trauma 7th Musculoskeletal Ultrasound Conference Portofino 1997 37.Evanski P: MRI of Ankle Tendons NYU Med Ctr New York 1997 38.Bard, R Ultrasound of Trauma to the Atlanto-Occipital Junction NY Academy of Traumatic Brain Injury NY Eye and Ear Infirmary New York 1998 39.Bard, R Ultrasound of the Normal and Abnormal Spine 4th International Congress of Ultrasound Madrid 1998 |
 |
