- Email: [email protected]
Ultrasound Evaluation of Achilles Tendinopathy
Journal of Medical Imaging and Radiation Sciences
Journal of Medical Imaging and Radiation Sciences 41 (2010) 133-136
Journal de l’imagerie médicale et des sciences de la radiation
www.elsevier.com/locate/jmir
Ultrasound Evaluation of Achilles Tendinopathy Emmanuel Ehiwe, MSc, PgD Educ, PgC, PgD Uss, DIRa*, Chyke I. Ohuegbe, MSc, BScb, and Rasheed Arogundade, MB, FMCR, FWACSc a
b
Spire Harpenden Hospital, Hertfordshire, UK In-Health Group, London Diagnostic Project, London, UK c Lagos University Teaching Hospital, Lagos, Nigeria
ABSTRACT Introduction: We sought to highlight the significance of ultrasound in assessing injuries to the Achilles tendon.
RE´SUME´ Objectif: Faire ressortir l’importance de l’ultrason dans l’e´valuation des blessures au tendon d’Achille.
Methods: Using a case study approach, we present two case reviews involving insertional enthesopathy and tendonitis of the Achilles.
Me´thodologie: A` partir d’une me´thode se rapprochant de l’e´tude de cas, nous pre´sentons deux cas sur l’enthe´sopathie des insertions et la tendinite du tendon d’Achille.
Results: Our study shows the lesions in the Achilles tendon and the peritendinous structures noted on clinical examination of the patients reviewed were better characterized with the use of ultrasound. Conclusion: This outcome is in line with information from available literature and current practice.
Introduction The spectrum of Achilles tendon injuries range from inflammation of the peritendinous tissue (peritendinitis), structural degeneration of the tendon (tendinosis), and partial or complete tendon rupture [1–3]. Acute total rupture of the Achilles is easily diagnosed clinically, but the sensitivity of detecting chronic tendinosis, peritendinitis or partial tears is reported to be about 0.7–0.8 [4, 5]. With sonographic features indicative of chronic Achilles tendinopathies, we present two cases involving patients with insertional enthesopathy and tendinitis of the Achilles. Case Review 1 A 42-year-old female weighing 85 kg presented with heel pain, palpable swelling, tenderness and reddening of the right heel. With a history of difficulty in walking over a 6-week period, the patient indicated that she had had no previous investigation or treatment of her heel pain. Initial clinical * Corresponding author: Emma Ehiwe, MSc, Pgd Educ, PgC, PgD Uss, DIR, Senior Radiographer, Spire Harpenden Hospital, Hertfordshire UK AL5 4BP. E-mail address: [email protected] (E. Ehiwe). 1939-8654/$ - see front matter Ó 2010 Published by Elsevier Inc. doi: 10.1016/j.jmir.2010.03.006
Re´sultats et conclusion: Notre e´tude indique qu’il e´tait plus facile de de´finir les le´sions du tendon d’Achille et des structures pe´ritendineuses releve´s par examen clinique des patients en utilisant l’ultrason. Le re´sultat est conforme a` la documentation actuelle et a` la pratique.
examination indicated Achilles tendonitis. Musculoskeletal ultrasound was requested to confirm clinical diagnosis and inform further line of management. Ultrasound scan reported chronic tendinopathy with insertional enthesopathy. The scan images showed the presence of focal hypoechoic area and thickening of the tendon just proximal to the insertion (measuring 16 mm thick). There was diffuse disruption of fibrillar echo pattern and multiple focal calcifications. Neovascularization on color Doppler interrogation was noted. On ultrasound, the tendon assumed a rounded appearance with loss of concave or flattened anterior contour. An area of marked decreased reflectivity was noted near the calcaneal insertion suggesting focal tendon split. There was no fluid in the retro-Achilles and pre-Achilles bursae, and the paratenon appeared normal and intact. There was slight increase in Kager’s fat pad echogenicity. No other calcaneal abnormalities were noted (Figures 1–4). Case Review 2 A 40-year-old female with swelling, pain and palpable tenderness of the left heel presented for ultrasound scan. No history of previous sporting activity or trauma was reported.
Figure 3. Longitudinal view of Figure 2. Figure 1. Transverse image showing thickened heteroechoic Achilles tendon and calcifications near the insertion, measuring 16mm thick in anteroposterior dimension.
Before the scan, the patient did not have any previous radiological investigation or physiotherapy. Ultrasound findings showed a diffuse hypoechoic, thickened Achilles tendon (about 5 cm from the insertion) measuring 13 mm thick. There was loss of fibrillar echo pattern anteriorly. The tendon appeared rounded in shape with loss of concave or flattened anterior contour. Color Doppler showed significant neovascularization. No definite focal split tear was seen, and there was no intratendon calcification. The insertion and myotendinous junction appeared intact. Normal appearance of the Kager’s fat pad, pre-Achilles and retro-Achilles bursae were reported (Figures 5–8). Discussion Chronic tendinopathy of the Achilles is a common overuse injury that causes considerable distress with pain and
Figure 2. Transverse image of the Achilles tendon showing the presence of focal hypoechoic areas and thickening of the Achilles tendon just proximal to the insertion. Calcifications with acoustic shadowing and neovascularization on power Doppler are noted.
134
disability [6]. Histology of the Achilles shows that tendinosis is a noninflammatory process resulting from a failed woundhealing cascade with evidence of disordered, haphazard healing; intratendinous collagen degeneration; fiber disorientation and thinning; hypercellularity; scattered vascular ingrowth; and increased interfibrillar glycosaminoglycans [7]. Studies have also shown that these areas of collagen degeneration correspond to the hypoechoic areas seen on sonography [8]. Although the etiology of Achilles tendinopathy is multifactorial in origin, it is reported to be caused by repetitive strain, increased age, trauma, rheumatoid arthritis and hypercholesterolemia [9]. Ultrasound is used to assess the heel area because it is a noninvasive, nonionizing, readily available, quick, safe and inexpensive imaging modality [10]. It also has the advantage of high resolution and color Doppler to assess vascularization of the Achilles tendon and other peritendinous structuresdsubcutaneous tissues, Kager’s fat pad or pre-Achilles fat pad, bursae, calcaneal insertion, plantar fascia and plantaris muscle. Other significant benefits of real-time sonography over other imaging modalities are that low kilovoltage x-rays and xeroradiography can only outline the
Figure 4. Transverse image of the Achilles tendon shows flattened anterior contour, with hypoechoic areas in the posterior part.
E. Ehiwe et al./Journal of Medical Imaging and Radiation Sciences 41 (2010) 133-136
Figure 5. Longitudinal image of the Achilles tendon showing a fusiformshaped, hypoechoic, thickened Achilles tendon.
silhouette of the Achilles and indicate the level of fluid accumulation in surrounding tissue [11]. This level of information is not sufficient to indicate fibrillar echo pattern or assess the presence of capillary vascularization in the Achilles as reported in the two cases discussed in this report. Research has also shown that although magnetic resonance imaging is excellent in soft-tissue contrast resolution of the Achilles and its adjacent bursae [12], and has the advantage of multiplanar capabilities to differentiate fluid collections in the heel from hematoma and other nonsanguinous collections; it is limited, however, by inaccessibility, cost and claustrophobia among patients who cannot tolerate the scanning procedure. This is unlike ultrasound, which is readily available, cheap, quick and safe to undertake [13]. The cases reviewed showed similar findings with areas of reduced reflectivity in the tendons with diffuse disruption of their fibrillar echo pattern. This is quite different from the normal sonographic outline of the normal tendon. The
Figure 6. Longitudinal image showing Achilles tendinopathy with neovascularization on power Doppler.
Figure 7. Split-screen images of the Achilles tendon in longitudinal and transverse sections. The heterogeneous appearance of the tendon is evident in the images.
tendons also showed thicknesses of 16 mm in Case 1 and 13 mm in Case 2, respectively. These increases in the anterior posterior plane diameter are 10 mm and 7 mm more than the average Achilles tendon dimension. The areas of decreased reflectivity also noted near the calcaneal insertion indicated marked tendon degeneration and partial tear. This is suggestive of early signs of tendon rupture and focal split in the paratendon sheath [14]. The presence of neovascularization reported in both patients also indicated the presence of blood circulation, which would not be found in the normal tendon sheath. Although tendon calcification is a rare finding in the normal Achilles [15], it was reported in the patient discussed in Case 1. This ultrasound finding was indicative of the level of chronicity [16] and degeneration of the Achilles [17] in that patient. It also highlights the advantage of ultrasound
Figure 8. Image of the Achilles tendon showing flattened anterior contour in the transverse view, with neovascularization. The tendon demonstrates a heterogeneous echogenicity.
E. Ehiwe et al./Journal of Medical Imaging and Radiation Sciences 41 (2010) 133-136
135
over other imaging modalities such as plain radiography and magnetic resonance imaging or computed tomography scan imaging. This is vital in view of the fact that magnetic resonance imaging is the gold standard in estimating the degree of tendon abnormalities [18] and differentiating among functional, morphologic and pathologic conditions [19]. Conclusion The Achilles tendonitis and the peritendinous injuries indicated on clinical examination were demonstrated using ultrasound. This helps to support the argument that realtime ultrasound is a veritable tool in demonstrating different types of abnormalities of the Achilles tendon. Acknowledgment We thank Dr. D.S. Shetty, consultant radiologist, Spire Harpenden Hospital, England, for peer reviewing this article. References [1] Leung, J. L., & Griffith, J. F. (2007). Sonography of chronic Achilles tendinopathy: a case-control study. J Clin Ultrasound 36: 27–32. [2] Jarvinen, T. A., Kannus, P., Maffulli, N., & Khan, K. M. (2005). Achilles tendon disorders: aetiology and epidemiology. Foot Ankle Clin 10: 255–266. [3] Reiter, M., Ulreich, N., Dirisamer, A., Tscholakoff, D., & Bucek, R. A. (2004). Colour and power Doppler sonography in symptomatic Achilles tendon disease. Int J Sports Med 25, 301–305. [4] Ohberg, L., Lorentzon, R., & Alfredson, H. (2001). Neovascularization in Achilles tendons with painful tendinosis but not in normal tendons: an ultrasonographic investigation. Knee Surg Sports Traumatol Arthrosc 9, 233. [5] Richards, P. J., Dheer, A. K., & McCall, I. M. (2003). Achilles tendon (TA) size and power Doppler ultrasound (PD) changes tendon pain and related pathologies: diagnosis by ultrasonography. Isr Med Assoc J 3, 575–578. [6] Grechening, W., Clement, H., Bratschitsch, G., Frankhauser, F., & Peicha, G. (2002). Ultrasound diagnosis of the Achilles tendon. Orthopade 31, 319–325.
136
[7] Zanetti, M., Metzdorf, A., Kundert, H. P., Zollinger, H., Vienne, P., Seifert, B., & Hodler, J. (2003). Achilles tendons: clinical relevance of neovascularization diagnosed with power Doppler US. Radiology 227, 556–560. [8] Richards, P. J., Braid, J. C., Carmont, M. R., & Maffulli, N. (2008). Achilles tendon ossification: pathology, imaging and etiology. Disabil Rehabil 30, 1651–1665. [9] Beeharry, D., Coupe, B., Benbow, E. W., Morgan, J., Kwok, S., & Charlton-Menys, V., et al. (2006). Familial hypercholesterolemia commonly presents with Achilles tenosynovitis. Ann Rheum Dis 65, 312–315. [10] Ying, M., Yeung, E., Li, B., Li, W., Lui, M., & Chi-Wai, T. S. O. (2003). Sonographic evaluation of the size of Achilles tendon: the effect of exercise and dominance of the ankle. Ultrasound Med Biol 29, 637–642. [11] Gibbon, W. W., Cooper, J. R., & Radcliffe, G. S. (2000). Distribution of sonographically detected tendon abnormalities in patients with a clinical diagnosis of chronic Achilles tendinosis. J Clin Ultrasound 28, 61–66. [12] Maffulli, N., Sharma, P., & Luscombe, K. L. (2004). Achilles tendinopathy: aetiology and management. J R Soc Med 97, 472–476. [13] Bleakney, R. R., & White, L. M. (2005). Imaging the Achilles tendon. Foot Ankle Clin North Am 10, 239–254. [14] Hartgerink, P., Fessell, D. P., Jacobson, J. A., & van Holsbeeck, M. T. (2001). Full-versus partial-thickness Achilles tendon tears: sonographic accuracy and characterization in 26 cases with surgical correlation. Radiology 220, 406–412. [15] Rawool, N. M., & Nazarian, L. N. (2000). Ultrasound of the ankle and foot. Semin Ultrasound CT MR 21, 275–284. [16] Blankstein, A., Cohen, I., Diamant, L., Heim, M., Dudkiewicz, I., & Israel, A., et al. (2001). Achilles tendon pain and related pathologies: diagnosis by ultrasonography. Isr Med Assoc J 3, 575–578. [17] De Zord, T., Fink, C., Feuchtner, G. M., Smekal, V., Reindl, M., & Klauser, A. S. (2009). Real-time sonoelastography findings in healthy Achilles tendons. AJR Am J Roentgenol 193, 134–138. [18] Khan, K., Forster, B., Robinson, J., Cheong, Y., Louise, L., & Maclean, L., et al. (2003). Are ultrasound and magnetic resonance imaging of value in assessment of Achilles tendon disorders? A two year prospective study. Br J Sports Med 37, 149–153. [19] Kamel, M., Eid, H., & Mansour, R. (2004). Ultrasound detection of heel enthesitis: a comparison with magnetic resonance imaging. J Rheumatol 31, 1465–1466.
E. Ehiwe et al./Journal of Medical Imaging and Radiation Sciences 41 (2010) 133-136
Journal of Medical Imaging and Radiation Sciences 41 (2010) 133-136
Journal de l’imagerie médicale et des sciences de la radiation
www.elsevier.com/locate/jmir
Ultrasound Evaluation of Achilles Tendinopathy Emmanuel Ehiwe, MSc, PgD Educ, PgC, PgD Uss, DIRa*, Chyke I. Ohuegbe, MSc, BScb, and Rasheed Arogundade, MB, FMCR, FWACSc a
b
Spire Harpenden Hospital, Hertfordshire, UK In-Health Group, London Diagnostic Project, London, UK c Lagos University Teaching Hospital, Lagos, Nigeria
ABSTRACT Introduction: We sought to highlight the significance of ultrasound in assessing injuries to the Achilles tendon.
RE´SUME´ Objectif: Faire ressortir l’importance de l’ultrason dans l’e´valuation des blessures au tendon d’Achille.
Methods: Using a case study approach, we present two case reviews involving insertional enthesopathy and tendonitis of the Achilles.
Me´thodologie: A` partir d’une me´thode se rapprochant de l’e´tude de cas, nous pre´sentons deux cas sur l’enthe´sopathie des insertions et la tendinite du tendon d’Achille.
Results: Our study shows the lesions in the Achilles tendon and the peritendinous structures noted on clinical examination of the patients reviewed were better characterized with the use of ultrasound. Conclusion: This outcome is in line with information from available literature and current practice.
Introduction The spectrum of Achilles tendon injuries range from inflammation of the peritendinous tissue (peritendinitis), structural degeneration of the tendon (tendinosis), and partial or complete tendon rupture [1–3]. Acute total rupture of the Achilles is easily diagnosed clinically, but the sensitivity of detecting chronic tendinosis, peritendinitis or partial tears is reported to be about 0.7–0.8 [4, 5]. With sonographic features indicative of chronic Achilles tendinopathies, we present two cases involving patients with insertional enthesopathy and tendinitis of the Achilles. Case Review 1 A 42-year-old female weighing 85 kg presented with heel pain, palpable swelling, tenderness and reddening of the right heel. With a history of difficulty in walking over a 6-week period, the patient indicated that she had had no previous investigation or treatment of her heel pain. Initial clinical * Corresponding author: Emma Ehiwe, MSc, Pgd Educ, PgC, PgD Uss, DIR, Senior Radiographer, Spire Harpenden Hospital, Hertfordshire UK AL5 4BP. E-mail address: [email protected] (E. Ehiwe). 1939-8654/$ - see front matter Ó 2010 Published by Elsevier Inc. doi: 10.1016/j.jmir.2010.03.006
Re´sultats et conclusion: Notre e´tude indique qu’il e´tait plus facile de de´finir les le´sions du tendon d’Achille et des structures pe´ritendineuses releve´s par examen clinique des patients en utilisant l’ultrason. Le re´sultat est conforme a` la documentation actuelle et a` la pratique.
examination indicated Achilles tendonitis. Musculoskeletal ultrasound was requested to confirm clinical diagnosis and inform further line of management. Ultrasound scan reported chronic tendinopathy with insertional enthesopathy. The scan images showed the presence of focal hypoechoic area and thickening of the tendon just proximal to the insertion (measuring 16 mm thick). There was diffuse disruption of fibrillar echo pattern and multiple focal calcifications. Neovascularization on color Doppler interrogation was noted. On ultrasound, the tendon assumed a rounded appearance with loss of concave or flattened anterior contour. An area of marked decreased reflectivity was noted near the calcaneal insertion suggesting focal tendon split. There was no fluid in the retro-Achilles and pre-Achilles bursae, and the paratenon appeared normal and intact. There was slight increase in Kager’s fat pad echogenicity. No other calcaneal abnormalities were noted (Figures 1–4). Case Review 2 A 40-year-old female with swelling, pain and palpable tenderness of the left heel presented for ultrasound scan. No history of previous sporting activity or trauma was reported.
Figure 3. Longitudinal view of Figure 2. Figure 1. Transverse image showing thickened heteroechoic Achilles tendon and calcifications near the insertion, measuring 16mm thick in anteroposterior dimension.
Before the scan, the patient did not have any previous radiological investigation or physiotherapy. Ultrasound findings showed a diffuse hypoechoic, thickened Achilles tendon (about 5 cm from the insertion) measuring 13 mm thick. There was loss of fibrillar echo pattern anteriorly. The tendon appeared rounded in shape with loss of concave or flattened anterior contour. Color Doppler showed significant neovascularization. No definite focal split tear was seen, and there was no intratendon calcification. The insertion and myotendinous junction appeared intact. Normal appearance of the Kager’s fat pad, pre-Achilles and retro-Achilles bursae were reported (Figures 5–8). Discussion Chronic tendinopathy of the Achilles is a common overuse injury that causes considerable distress with pain and
Figure 2. Transverse image of the Achilles tendon showing the presence of focal hypoechoic areas and thickening of the Achilles tendon just proximal to the insertion. Calcifications with acoustic shadowing and neovascularization on power Doppler are noted.
134
disability [6]. Histology of the Achilles shows that tendinosis is a noninflammatory process resulting from a failed woundhealing cascade with evidence of disordered, haphazard healing; intratendinous collagen degeneration; fiber disorientation and thinning; hypercellularity; scattered vascular ingrowth; and increased interfibrillar glycosaminoglycans [7]. Studies have also shown that these areas of collagen degeneration correspond to the hypoechoic areas seen on sonography [8]. Although the etiology of Achilles tendinopathy is multifactorial in origin, it is reported to be caused by repetitive strain, increased age, trauma, rheumatoid arthritis and hypercholesterolemia [9]. Ultrasound is used to assess the heel area because it is a noninvasive, nonionizing, readily available, quick, safe and inexpensive imaging modality [10]. It also has the advantage of high resolution and color Doppler to assess vascularization of the Achilles tendon and other peritendinous structuresdsubcutaneous tissues, Kager’s fat pad or pre-Achilles fat pad, bursae, calcaneal insertion, plantar fascia and plantaris muscle. Other significant benefits of real-time sonography over other imaging modalities are that low kilovoltage x-rays and xeroradiography can only outline the
Figure 4. Transverse image of the Achilles tendon shows flattened anterior contour, with hypoechoic areas in the posterior part.
E. Ehiwe et al./Journal of Medical Imaging and Radiation Sciences 41 (2010) 133-136
Figure 5. Longitudinal image of the Achilles tendon showing a fusiformshaped, hypoechoic, thickened Achilles tendon.
silhouette of the Achilles and indicate the level of fluid accumulation in surrounding tissue [11]. This level of information is not sufficient to indicate fibrillar echo pattern or assess the presence of capillary vascularization in the Achilles as reported in the two cases discussed in this report. Research has also shown that although magnetic resonance imaging is excellent in soft-tissue contrast resolution of the Achilles and its adjacent bursae [12], and has the advantage of multiplanar capabilities to differentiate fluid collections in the heel from hematoma and other nonsanguinous collections; it is limited, however, by inaccessibility, cost and claustrophobia among patients who cannot tolerate the scanning procedure. This is unlike ultrasound, which is readily available, cheap, quick and safe to undertake [13]. The cases reviewed showed similar findings with areas of reduced reflectivity in the tendons with diffuse disruption of their fibrillar echo pattern. This is quite different from the normal sonographic outline of the normal tendon. The
Figure 6. Longitudinal image showing Achilles tendinopathy with neovascularization on power Doppler.
Figure 7. Split-screen images of the Achilles tendon in longitudinal and transverse sections. The heterogeneous appearance of the tendon is evident in the images.
tendons also showed thicknesses of 16 mm in Case 1 and 13 mm in Case 2, respectively. These increases in the anterior posterior plane diameter are 10 mm and 7 mm more than the average Achilles tendon dimension. The areas of decreased reflectivity also noted near the calcaneal insertion indicated marked tendon degeneration and partial tear. This is suggestive of early signs of tendon rupture and focal split in the paratendon sheath [14]. The presence of neovascularization reported in both patients also indicated the presence of blood circulation, which would not be found in the normal tendon sheath. Although tendon calcification is a rare finding in the normal Achilles [15], it was reported in the patient discussed in Case 1. This ultrasound finding was indicative of the level of chronicity [16] and degeneration of the Achilles [17] in that patient. It also highlights the advantage of ultrasound
Figure 8. Image of the Achilles tendon showing flattened anterior contour in the transverse view, with neovascularization. The tendon demonstrates a heterogeneous echogenicity.
E. Ehiwe et al./Journal of Medical Imaging and Radiation Sciences 41 (2010) 133-136
135
over other imaging modalities such as plain radiography and magnetic resonance imaging or computed tomography scan imaging. This is vital in view of the fact that magnetic resonance imaging is the gold standard in estimating the degree of tendon abnormalities [18] and differentiating among functional, morphologic and pathologic conditions [19]. Conclusion The Achilles tendonitis and the peritendinous injuries indicated on clinical examination were demonstrated using ultrasound. This helps to support the argument that realtime ultrasound is a veritable tool in demonstrating different types of abnormalities of the Achilles tendon. Acknowledgment We thank Dr. D.S. Shetty, consultant radiologist, Spire Harpenden Hospital, England, for peer reviewing this article. References [1] Leung, J. L., & Griffith, J. F. (2007). Sonography of chronic Achilles tendinopathy: a case-control study. J Clin Ultrasound 36: 27–32. [2] Jarvinen, T. A., Kannus, P., Maffulli, N., & Khan, K. M. (2005). Achilles tendon disorders: aetiology and epidemiology. Foot Ankle Clin 10: 255–266. [3] Reiter, M., Ulreich, N., Dirisamer, A., Tscholakoff, D., & Bucek, R. A. (2004). Colour and power Doppler sonography in symptomatic Achilles tendon disease. Int J Sports Med 25, 301–305. [4] Ohberg, L., Lorentzon, R., & Alfredson, H. (2001). Neovascularization in Achilles tendons with painful tendinosis but not in normal tendons: an ultrasonographic investigation. Knee Surg Sports Traumatol Arthrosc 9, 233. [5] Richards, P. J., Dheer, A. K., & McCall, I. M. (2003). Achilles tendon (TA) size and power Doppler ultrasound (PD) changes tendon pain and related pathologies: diagnosis by ultrasonography. Isr Med Assoc J 3, 575–578. [6] Grechening, W., Clement, H., Bratschitsch, G., Frankhauser, F., & Peicha, G. (2002). Ultrasound diagnosis of the Achilles tendon. Orthopade 31, 319–325.
136
[7] Zanetti, M., Metzdorf, A., Kundert, H. P., Zollinger, H., Vienne, P., Seifert, B., & Hodler, J. (2003). Achilles tendons: clinical relevance of neovascularization diagnosed with power Doppler US. Radiology 227, 556–560. [8] Richards, P. J., Braid, J. C., Carmont, M. R., & Maffulli, N. (2008). Achilles tendon ossification: pathology, imaging and etiology. Disabil Rehabil 30, 1651–1665. [9] Beeharry, D., Coupe, B., Benbow, E. W., Morgan, J., Kwok, S., & Charlton-Menys, V., et al. (2006). Familial hypercholesterolemia commonly presents with Achilles tenosynovitis. Ann Rheum Dis 65, 312–315. [10] Ying, M., Yeung, E., Li, B., Li, W., Lui, M., & Chi-Wai, T. S. O. (2003). Sonographic evaluation of the size of Achilles tendon: the effect of exercise and dominance of the ankle. Ultrasound Med Biol 29, 637–642. [11] Gibbon, W. W., Cooper, J. R., & Radcliffe, G. S. (2000). Distribution of sonographically detected tendon abnormalities in patients with a clinical diagnosis of chronic Achilles tendinosis. J Clin Ultrasound 28, 61–66. [12] Maffulli, N., Sharma, P., & Luscombe, K. L. (2004). Achilles tendinopathy: aetiology and management. J R Soc Med 97, 472–476. [13] Bleakney, R. R., & White, L. M. (2005). Imaging the Achilles tendon. Foot Ankle Clin North Am 10, 239–254. [14] Hartgerink, P., Fessell, D. P., Jacobson, J. A., & van Holsbeeck, M. T. (2001). Full-versus partial-thickness Achilles tendon tears: sonographic accuracy and characterization in 26 cases with surgical correlation. Radiology 220, 406–412. [15] Rawool, N. M., & Nazarian, L. N. (2000). Ultrasound of the ankle and foot. Semin Ultrasound CT MR 21, 275–284. [16] Blankstein, A., Cohen, I., Diamant, L., Heim, M., Dudkiewicz, I., & Israel, A., et al. (2001). Achilles tendon pain and related pathologies: diagnosis by ultrasonography. Isr Med Assoc J 3, 575–578. [17] De Zord, T., Fink, C., Feuchtner, G. M., Smekal, V., Reindl, M., & Klauser, A. S. (2009). Real-time sonoelastography findings in healthy Achilles tendons. AJR Am J Roentgenol 193, 134–138. [18] Khan, K., Forster, B., Robinson, J., Cheong, Y., Louise, L., & Maclean, L., et al. (2003). Are ultrasound and magnetic resonance imaging of value in assessment of Achilles tendon disorders? A two year prospective study. Br J Sports Med 37, 149–153. [19] Kamel, M., Eid, H., & Mansour, R. (2004). Ultrasound detection of heel enthesitis: a comparison with magnetic resonance imaging. J Rheumatol 31, 1465–1466.
E. Ehiwe et al./Journal of Medical Imaging and Radiation Sciences 41 (2010) 133-136