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Discrimination between calcified triticeous cartilage and calcified carotid atheroma on panoramic radiography
Discrimination between calcified triticeous cartilage and calcified carotid atheroma on panoramic radiography Laurie C. Carter, DDS, MA, PhD,a Buffalo, NY STATE UNIVERSITY OF NEW YORK
The differential diagnosis of calcified atherosclerotic plaque in the extracranial carotid vasculature includes a number of anatomic and pathologic radiopacities. Most of these are readily distinguishable on the basis of location and morphologic features. The calcified triticeous cartilage, however, can be a confounding alternative that is frequently misdiagnosed as a calcified atheroma. This paper describes the radiographic differences between these 2 entities, enabling clinicians to improve their diagnostic acumen when evaluating cervical soft tissue calcifications. (Oral Surg Oral Med Oral Pathol
Oral Radiol Endod 2000;90:108-10)
The review of existing panoramic radiographs for the presence of calcified atherosclerotic plaque in the extracranial carotid vasculature has enjoyed considerable interest in recent years.1-9 During this review process, the clinician must distinguish calcified carotid artery atheromas from anatomic and pathologic radiopacities that lie in close proximity to the vessel. Neighboring anatomic radiopacities include the hyoid bone, epiglottis, and mineralized stylomandibular and stylohyoid ligaments. Pathologic radiopacities that may present in the region of the vessel include calcified thyroid or submandibular gland, sialoliths, phleboliths, calcified lymph nodes, and tonsilloliths. Based on the location and typical morphology of the above-mentioned entities, there is rarely a problem in distinguishing them from calcified atheromas. However, many practitioners are unaware that a calcified triticeous cartilage, or less frequently the superior horn of a calcified thyroid cartilage, may be mistaken for calcified arterial plaque. The purpose of this manuscript is to provide assistance in identifying these variants of normal and to raise clinicians’ awareness of the existence of these structures to reduce the likelihood that they will be misdiagnosed as calcified carotid atheromas. In addition to the thyroid, arytenoid, and cricoid cartilages, 3 smaller pairs of cartilages form part of the upper laryngeal skeleton (Fig 1).10 The corniculate cartilages are small paired structures situated immediately superior to the arytenoids. Just lateral and superior to the corniculate cartilages, buried in the aryepiglottic folds, are the thin cuneiform cartilages. The round, cord-like lateral aAssociate Professor and Director Oral and Maxillofacial Diagnostic Imaging Clinic, Director of Patient Admissions, Department of Oral Diagnostic Sciences, School of Dental Medicine, University at Buffalo, State University of New York. Received for publication Oct 18, 1999; accepted for publication Jan 19, 2000. Copyright © 2000 by Mosby, Inc. 1079-2104/2000/$12.00 + 0 7/16/106297 doi:10.1067/moe.2000.106297
108
Fig 1. Sketch illustrates morphology and location of calcified triticeous cartilage (T), superior cornu of calcified thyroid cartilage (S) and calcified carotid atheroma (C) as they appear on panoramic radiograph. Also labeled are the following normal anatomic landmarks: epiglottis (E), greater cornu of hyoid bone (H), soft tissue of base of tongue (B), prevertebral soft tissue (P) and parapharyngeal air space (A).
thyrohyoid ligaments form the posterior borders of the thyrohyoid membrane, connecting the posterior aspect of the greater cornua of the hyoid bone with the superior cornua of the thyroid cartilage on each side.11 The small paired triticeous cartilages are found centrally within the posterior free edge of the lateral thyrohyoid ligaments. These ovoid radiopacities, approximately 2 to 4 mm wide by 7 to 9 mm in length, are usually imaged within the pharyngeal air space adjacent to the superior portion of C4 (Fig 2).12,13 The word triticeous comes from the Latin triticeus, meaning resembling a grain of wheat.14 The function of the triticeous cartilage is unknown,
Carter 109
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY Volume 90, Number 1
A
A
B B Fig 2. Cropped panoramic radiographs demonstrate features of calcified triticeous cartilage. Also indicated are hyoid bone (H) and epiglottis (E). A, 54-year-old woman. B, 60-year-old man.
although it is postulated that it may serve to strengthen the lateral thyrohyoid ligament.13 Calcification of tracheobronchial, laryngeal, and costochondral cartilages are unusual radiologic findings in infants and children under 13 years of age.15 According to Haddad et al,16 in children, calcification in these cartilages only occurs under pathologic conditions (eg, severe respiratory stridor, Keutel syndrome, chondrodysplasia punctata, hypercalcemia, or hypervitaminosis D) or in acquired states, such as warfarin embryopathy.16 Although the cartilages of the laryngeal skeleton are initially hyaline in nature, the corniculate and cuneiform cartilages, the epiglottis, and the apices of the arytenoids
Fig 3. Cropped panoramic radiographs demonstrate superior cornu of calcified thyroid cartilage. Also indicated are hyoid bone (H) and epiglottis (E). A, Film cassette positioned too inferiorly; entire length of calcified cornu visible (arrowheads). B, With proper positioning, only very tip of calcified cornu is visible (arrowhead).
are transformed into elastic cartilage with aging.13 However, the thyroid, cricoid, triticeum, and greater wing of the arytenoid cartilages remain hyaline.17 This anatomic variation is of considerable radiologic significance because elastic cartilage shows little tendency to calcify whereas hyaline cartilages show a propensity to calcify and even ossify with advancing age. The superior cornu of a calcified thyroid cartilage is imaged on the panoramic radiograph as a vertical soft tissue calcification approximately 4 mm wide and 15 mm in length, medial to the image of C4 superimposed over the prever-
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needed for calcified triticeous cartilage, but patients with calcified carotid atheromata should be referred to their physicians for further evaluation to determine the risk of cerebrovascular accident. Thanks to Mr John Nyquist and Mr James Ulrich, Art and Photographic Services, University at Buffalo, for their assistance in biomedical illustration and in the translation of fine radiographic details onto photographic paper. REFERENCES
Fig 4. Cropped panoramic radiograph illustrating calcified carotid atheroma in region of bifurcation adjacent to ghost image of C3-C4, epiglottis, and greater cornu of hyoid bone, superimposed on prevertebral soft tissue.
tebral soft tissue (Fig 3). Generally, only the top 2 to 3 mm of this calcified cartilage will be visible at the lower edge of the panoramic radiograph. Only if the cassette is positioned too far inferiorly will a greater length of this cartilage be visualized. Hately et al12 examined a series of 516 unselected neck radiographs to evaluate normal patterns and variations in calcification in the laryngeal cartilages. In the age group 21 to 80, 29% of men and 22% of women demonstrated calcification of the triticeous cartilages, the earliest cases being 2 women, both aged 23 years.12 On average, the laryngeal cartilages of men contain a greater area of calcification than those of women, but great variations occur in both sexes.18 No single pattern of calcium deposition in the laryngeal skeleton has been described. Although, as a general trend, calcification increases with advancing age, the absolute prevalence and degree of calcification and chronologic age have not been well correlated.19 On the other hand, calcified carotid atheromas occurring at the bifurcation of the artery are visualized as irregular, heterogeneous, verticolinear radiopacities inferior to the angle of the mandible and adjacent to the images of C3, C4, or both, superimposed over the prevertebral soft tissue (Fig 4). Calcified carotid atheromas appear more laterally on the panoramic radiograph than a calcified triticeous cartilage would.7 Careful attention to these differences in morphology and location should enable the clinician to distinguish between calcified triticeous cartilage and calcified carotid atheroma. No treatment is
1. Friedlander A, Lande A. Panoramic x-ray identification of carotid arterial plaques. Oral Surg, Oral Med, Oral Pathol 1981;52:102-4. 2. Friedlander A, Baker J. Panoramic radiography: an aid in detecting patients at risk of cerebrovascular accident. J Am Dent Assoc 1994;125:1598-603. 3. Friedlander A, Gratt B. Panoramic dental radiography and electronic thermography: aids in detecting patients at risk for stroke. J Oral Maxillofac Surg 1994;52:1257-62. 4. Friedlander A. Identification of stroke-prone patients by panoramic and cervical spine radiography. Dentomaxillofac Radiol 1995;24:160-4. 5. Friedlander A. Panoramic radiography: the differential diagnosis of carotid artery atheromas. Spec Care Dentist 1995;15:223-7. 6. Crouse J. Heart of the matter in cerebral arterial sclerosis. Lancet 1996;348:766. 7. Carter L, Haller A, Nadarajah V, Calamel A, Aguirre A. Use of panoramic radiography among an ambulatory dental population to detect patients at risk of stroke. J Am Dent Assoc 1997;128:977-84. 8. Carter L, Tsimidis K, Fabiano J. Carotid calcifications on panoramic radiography identify an asymptomatic male patient at risk for stroke. Oral Surg, Oral Med, Oral Pathol, Oral Radiol, Endod 1998;85:119-22. 9. Lewis D, Brooks S. Carotid artery calcification in a general dental population: a retrospective study of panoramic radiographs. Gen Dent 1999;47:98-103. 10. Curtin H. Larynx. In: Som P, Curtin H, editors. Head and neck imaging. Vol 1. St Louis: CV Mosby Co; 1996. p. 615-21. 11. Avrahami E, Harel M, Englender M. CT evaluation of displaced superior cornu of ossified thyroid cartilage. Clin Radiol 1994;49: 683-5. 12. Hately W, Evison G, Samuel E. The pattern of ossification in the laryngeal cartilages: a radiological study. Brit J Radiol 1965;38: 585-91. 13. Williams P, chairman of the editorial board. Gray’s anatomy: the anatomical basis of medicine and surgery. 38th ed. New York: Churchill Livingstone; 1995. p. 1639-42. 14. Taylor E, editor. Dorland’s illustrated medical dictionary. 27th ed. Philadelphia: WB Saunders; 1988. 15. Fukuya T, Mihara F, Kudo S, Russell WJ, Longchamp R, Vaeth M. Tracheobronchial calcification in members of a fixed population sample. Acta Radiologica 1989;30:277-80. 16. Haddad M, Sharif H, Jared M, Sammak B, Shahed M. Premature tracheobronchial, laryngeal and costochondral cartilage calcification in children. Clin Radiol 1993;47:52-5. 17. Jurik A. Ossification and calcification of the laryngeal skeleton. Acta Radiol Diagnosis 1984 (Fasc. 1); 25:17-22. 18. Yeager V, Lawson C, Archer C. Ossification of the laryngeal arches as it relates to computed tomography. Invest Radiol 1982;17:11-9. 19. Yerman H, Werkhaven J, Schild J. Evaluation of laryngeal calcium deposition: a new methodology. Ann Otol Rhinol Laryngol 1988;97:516-20. Reprint requests: Laurie Carter, DDS, PhD Department of Oral Diagnostic Sciences 355 Squire Hall, School of Dental Medicine State University of New York University at Buffalo Buffalo, NY 14214-3008 [email protected]
The differential diagnosis of calcified atherosclerotic plaque in the extracranial carotid vasculature includes a number of anatomic and pathologic radiopacities. Most of these are readily distinguishable on the basis of location and morphologic features. The calcified triticeous cartilage, however, can be a confounding alternative that is frequently misdiagnosed as a calcified atheroma. This paper describes the radiographic differences between these 2 entities, enabling clinicians to improve their diagnostic acumen when evaluating cervical soft tissue calcifications. (Oral Surg Oral Med Oral Pathol
Oral Radiol Endod 2000;90:108-10)
The review of existing panoramic radiographs for the presence of calcified atherosclerotic plaque in the extracranial carotid vasculature has enjoyed considerable interest in recent years.1-9 During this review process, the clinician must distinguish calcified carotid artery atheromas from anatomic and pathologic radiopacities that lie in close proximity to the vessel. Neighboring anatomic radiopacities include the hyoid bone, epiglottis, and mineralized stylomandibular and stylohyoid ligaments. Pathologic radiopacities that may present in the region of the vessel include calcified thyroid or submandibular gland, sialoliths, phleboliths, calcified lymph nodes, and tonsilloliths. Based on the location and typical morphology of the above-mentioned entities, there is rarely a problem in distinguishing them from calcified atheromas. However, many practitioners are unaware that a calcified triticeous cartilage, or less frequently the superior horn of a calcified thyroid cartilage, may be mistaken for calcified arterial plaque. The purpose of this manuscript is to provide assistance in identifying these variants of normal and to raise clinicians’ awareness of the existence of these structures to reduce the likelihood that they will be misdiagnosed as calcified carotid atheromas. In addition to the thyroid, arytenoid, and cricoid cartilages, 3 smaller pairs of cartilages form part of the upper laryngeal skeleton (Fig 1).10 The corniculate cartilages are small paired structures situated immediately superior to the arytenoids. Just lateral and superior to the corniculate cartilages, buried in the aryepiglottic folds, are the thin cuneiform cartilages. The round, cord-like lateral aAssociate Professor and Director Oral and Maxillofacial Diagnostic Imaging Clinic, Director of Patient Admissions, Department of Oral Diagnostic Sciences, School of Dental Medicine, University at Buffalo, State University of New York. Received for publication Oct 18, 1999; accepted for publication Jan 19, 2000. Copyright © 2000 by Mosby, Inc. 1079-2104/2000/$12.00 + 0 7/16/106297 doi:10.1067/moe.2000.106297
108
Fig 1. Sketch illustrates morphology and location of calcified triticeous cartilage (T), superior cornu of calcified thyroid cartilage (S) and calcified carotid atheroma (C) as they appear on panoramic radiograph. Also labeled are the following normal anatomic landmarks: epiglottis (E), greater cornu of hyoid bone (H), soft tissue of base of tongue (B), prevertebral soft tissue (P) and parapharyngeal air space (A).
thyrohyoid ligaments form the posterior borders of the thyrohyoid membrane, connecting the posterior aspect of the greater cornua of the hyoid bone with the superior cornua of the thyroid cartilage on each side.11 The small paired triticeous cartilages are found centrally within the posterior free edge of the lateral thyrohyoid ligaments. These ovoid radiopacities, approximately 2 to 4 mm wide by 7 to 9 mm in length, are usually imaged within the pharyngeal air space adjacent to the superior portion of C4 (Fig 2).12,13 The word triticeous comes from the Latin triticeus, meaning resembling a grain of wheat.14 The function of the triticeous cartilage is unknown,
Carter 109
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY Volume 90, Number 1
A
A
B B Fig 2. Cropped panoramic radiographs demonstrate features of calcified triticeous cartilage. Also indicated are hyoid bone (H) and epiglottis (E). A, 54-year-old woman. B, 60-year-old man.
although it is postulated that it may serve to strengthen the lateral thyrohyoid ligament.13 Calcification of tracheobronchial, laryngeal, and costochondral cartilages are unusual radiologic findings in infants and children under 13 years of age.15 According to Haddad et al,16 in children, calcification in these cartilages only occurs under pathologic conditions (eg, severe respiratory stridor, Keutel syndrome, chondrodysplasia punctata, hypercalcemia, or hypervitaminosis D) or in acquired states, such as warfarin embryopathy.16 Although the cartilages of the laryngeal skeleton are initially hyaline in nature, the corniculate and cuneiform cartilages, the epiglottis, and the apices of the arytenoids
Fig 3. Cropped panoramic radiographs demonstrate superior cornu of calcified thyroid cartilage. Also indicated are hyoid bone (H) and epiglottis (E). A, Film cassette positioned too inferiorly; entire length of calcified cornu visible (arrowheads). B, With proper positioning, only very tip of calcified cornu is visible (arrowhead).
are transformed into elastic cartilage with aging.13 However, the thyroid, cricoid, triticeum, and greater wing of the arytenoid cartilages remain hyaline.17 This anatomic variation is of considerable radiologic significance because elastic cartilage shows little tendency to calcify whereas hyaline cartilages show a propensity to calcify and even ossify with advancing age. The superior cornu of a calcified thyroid cartilage is imaged on the panoramic radiograph as a vertical soft tissue calcification approximately 4 mm wide and 15 mm in length, medial to the image of C4 superimposed over the prever-
110 Carter
ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY July 2000
needed for calcified triticeous cartilage, but patients with calcified carotid atheromata should be referred to their physicians for further evaluation to determine the risk of cerebrovascular accident. Thanks to Mr John Nyquist and Mr James Ulrich, Art and Photographic Services, University at Buffalo, for their assistance in biomedical illustration and in the translation of fine radiographic details onto photographic paper. REFERENCES
Fig 4. Cropped panoramic radiograph illustrating calcified carotid atheroma in region of bifurcation adjacent to ghost image of C3-C4, epiglottis, and greater cornu of hyoid bone, superimposed on prevertebral soft tissue.
tebral soft tissue (Fig 3). Generally, only the top 2 to 3 mm of this calcified cartilage will be visible at the lower edge of the panoramic radiograph. Only if the cassette is positioned too far inferiorly will a greater length of this cartilage be visualized. Hately et al12 examined a series of 516 unselected neck radiographs to evaluate normal patterns and variations in calcification in the laryngeal cartilages. In the age group 21 to 80, 29% of men and 22% of women demonstrated calcification of the triticeous cartilages, the earliest cases being 2 women, both aged 23 years.12 On average, the laryngeal cartilages of men contain a greater area of calcification than those of women, but great variations occur in both sexes.18 No single pattern of calcium deposition in the laryngeal skeleton has been described. Although, as a general trend, calcification increases with advancing age, the absolute prevalence and degree of calcification and chronologic age have not been well correlated.19 On the other hand, calcified carotid atheromas occurring at the bifurcation of the artery are visualized as irregular, heterogeneous, verticolinear radiopacities inferior to the angle of the mandible and adjacent to the images of C3, C4, or both, superimposed over the prevertebral soft tissue (Fig 4). Calcified carotid atheromas appear more laterally on the panoramic radiograph than a calcified triticeous cartilage would.7 Careful attention to these differences in morphology and location should enable the clinician to distinguish between calcified triticeous cartilage and calcified carotid atheroma. No treatment is
1. Friedlander A, Lande A. Panoramic x-ray identification of carotid arterial plaques. Oral Surg, Oral Med, Oral Pathol 1981;52:102-4. 2. Friedlander A, Baker J. Panoramic radiography: an aid in detecting patients at risk of cerebrovascular accident. J Am Dent Assoc 1994;125:1598-603. 3. Friedlander A, Gratt B. Panoramic dental radiography and electronic thermography: aids in detecting patients at risk for stroke. J Oral Maxillofac Surg 1994;52:1257-62. 4. Friedlander A. Identification of stroke-prone patients by panoramic and cervical spine radiography. Dentomaxillofac Radiol 1995;24:160-4. 5. Friedlander A. Panoramic radiography: the differential diagnosis of carotid artery atheromas. Spec Care Dentist 1995;15:223-7. 6. Crouse J. Heart of the matter in cerebral arterial sclerosis. Lancet 1996;348:766. 7. Carter L, Haller A, Nadarajah V, Calamel A, Aguirre A. Use of panoramic radiography among an ambulatory dental population to detect patients at risk of stroke. J Am Dent Assoc 1997;128:977-84. 8. Carter L, Tsimidis K, Fabiano J. Carotid calcifications on panoramic radiography identify an asymptomatic male patient at risk for stroke. Oral Surg, Oral Med, Oral Pathol, Oral Radiol, Endod 1998;85:119-22. 9. Lewis D, Brooks S. Carotid artery calcification in a general dental population: a retrospective study of panoramic radiographs. Gen Dent 1999;47:98-103. 10. Curtin H. Larynx. In: Som P, Curtin H, editors. Head and neck imaging. Vol 1. St Louis: CV Mosby Co; 1996. p. 615-21. 11. Avrahami E, Harel M, Englender M. CT evaluation of displaced superior cornu of ossified thyroid cartilage. Clin Radiol 1994;49: 683-5. 12. Hately W, Evison G, Samuel E. The pattern of ossification in the laryngeal cartilages: a radiological study. Brit J Radiol 1965;38: 585-91. 13. Williams P, chairman of the editorial board. Gray’s anatomy: the anatomical basis of medicine and surgery. 38th ed. New York: Churchill Livingstone; 1995. p. 1639-42. 14. Taylor E, editor. Dorland’s illustrated medical dictionary. 27th ed. Philadelphia: WB Saunders; 1988. 15. Fukuya T, Mihara F, Kudo S, Russell WJ, Longchamp R, Vaeth M. Tracheobronchial calcification in members of a fixed population sample. Acta Radiologica 1989;30:277-80. 16. Haddad M, Sharif H, Jared M, Sammak B, Shahed M. Premature tracheobronchial, laryngeal and costochondral cartilage calcification in children. Clin Radiol 1993;47:52-5. 17. Jurik A. Ossification and calcification of the laryngeal skeleton. Acta Radiol Diagnosis 1984 (Fasc. 1); 25:17-22. 18. Yeager V, Lawson C, Archer C. Ossification of the laryngeal arches as it relates to computed tomography. Invest Radiol 1982;17:11-9. 19. Yerman H, Werkhaven J, Schild J. Evaluation of laryngeal calcium deposition: a new methodology. Ann Otol Rhinol Laryngol 1988;97:516-20. Reprint requests: Laurie Carter, DDS, PhD Department of Oral Diagnostic Sciences 355 Squire Hall, School of Dental Medicine State University of New York University at Buffalo Buffalo, NY 14214-3008 [email protected]