Clinical Imaging xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
Clinical Imaging journal homepage: http://www.clinicalimaging.org
Prevalence of sternoclavicular joint calcium pyrophosphate dihydrate crystal deposition on computed tomography☆,☆☆ Hoda Shirazian a,⁎, Eric Y. Chang b, a, Tanya Wolfson a, Anthony C. Gamst a, Christine B. Chung b, a, Donald L. Resnick a a b
Department of Radiology, University of California, San Diego Medical Center Department of Radiology, VA San Diego Healthcare System
a r t i c l e
i n f o
Article history: Received 17 September 2013 Received in revised form 3 February 2014 Accepted 21 February 2014 Available online xxxx Keywords: CPPD Calcium pyrophosphate dihydrate Crystal deposition Sternoclavicular joint Computed tomography
a b s t r a c t We sought to determine the prevalence of sternoclavicular (SC) joint calcium pyrophosphate dihydrate (CPPD) crystal deposition and its association with age, osteoarthritis, and atlantoaxial CPPD crystal deposition. In 209 consecutive patients, computed tomographic examinations of the cervical spine were retrospectively reviewed. Overall prevalence of CPPD crystal deposition in the SC joint was 17.2% (36/209), which increased with age (Pb.0001). There was also a significant association between SC CPPD and osteoarthritis (P=.024) as well as atlantoaxial joint CPPD crystal deposition (P=.006).
1. Introduction Calcium pyrophosphate dihydrate (CPPD) crystal deposition can occur in the following three forms: hereditary, sporadic, or associated with other disorders such as metabolic and degenerative joint diseases [1,2]. CPPD crystals are usually observed bilaterally and symmetrically and are polyarticular in distribution [3,4]. Crystals may be apparent in cartilage (i.e., chondrocalcinosis), capsule, tendons, synovium, ligaments, bursae, and soft tissues [2]. Intraarticular chondrocalcinosis can be detected in both hyaline cartilage and fibrocartilage [1,2,5,6]. Calcification within fibrocartilage tends to appear thick and shaggy with irregular radiodense areas, particularly within the central aspect of the joint cavity. Calcification within hyaline cartilage has a thin linear appearance, paralleling the subjacent subchondral bone [2,6]. Previous studies have indicated that the prevalence of CPPD crystal deposition increases with age [5]. Although CPPD crystal deposition generally is clinically asymptomatic, symptoms such as acute or chronic arthritis, pain, stiffness, swelling, and decreased range of motion have been observed [6–8]. In the sternoclavicular (SC) joint, joint space narrowing and bone sclerosis in cases of CPPD crystal deposition
© 2014 Elsevier Inc. All rights reserved.
resemble osteoarthritis [9]. Additionally, however, calcification in hyaline cartilage or fibrocartilage, or both, may be evident, and perforation of the intraarticular disk is reported [10]. There are extensive studies about CPPD crystal deposition that have emphasized the importance of monitoring this condition [2,5,7,10–14]. Furthermore, a recent study has confirmed an increased prevalence of CPPD crystal deposition in the atlantoaxial joint when compared with reported data and has found a positive correlation with age and retroodontoid soft tissue thickness [1]. To our knowledge, this is the first study in which the prevalence of CPPD crystal deposition in the SC joint is examined. To date, only a few case reports on this subject have been reported, which have focused on associated symptoms such as tenderness and swelling of the SC joint due to compression from the calcified mass [3,14]. The purpose of this study was to (a) determine the prevalence of SC joint CPPD crystal deposition in a population of patients undergoing computed tomographic (CT) scanning for assessment of acute trauma and (b) to determine the association of SC joint CPPD crystal deposition with age, osteoarthritis, and atlantoaxial CPPD crystal deposition. 2. Material and methods
☆ Work performed at University of California, San Diego Medical Center. ☆☆ Eric Y. Chang, M.D., graciously acknowledges salary support from a VA CSR&D Career Development Award (5IK2CX000749). ⁎ Corresponding author. 8899 University center Lane, suit 370, San Diego, CA 92122. Tel.: +1 858 246 1011; fax: +1 858 552 9126. E-mail address: [email protected] (H. Shirazian).
Our institutional review board approved this retrospective, HIPAAcompliant study with an exemption of informed consent. We used our picture archive and communication system (PACS) to search the medical records of all patients who were admitted to our Level I trauma center
0899-7071/$ – see front matter © 2014 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.clinimag.2014.02.016
Please cite this article as: Shirazian H, et al, Prevalence of sternoclavicular joint calcium pyrophosphate dihydrate crystal deposition on computed tomography, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.02.016
2
H. Shirazian et al. / Clinical Imaging xxx (2014) xxx–xxx
(both trauma triage and emergency room cases) between January 1, 2010, and March 31, 2010. Trauma patients underwent CT scanning of both the head and the cervical spine as part of our routine trauma protocol. As part of our search criteria, cases were included if images of the cervical spine and/or thorax were available. With this protocol in place, our search yielded 521 patients that had received, at the minimum, CT imaging of the cervical spine and head. Of the 521, 304 patients were excluded because the SC joint was not entirely included in the field of view, 5 patients were excluded because the age of the patient was not documented, and 3 patients were excluded due to metallic artifact. In total, 209 patients were included in our study. 2.1. Image acquisition and analysis Patients underwent imaging from the occiput to T4 with either a 64row (CT750 HD, GE Healthcare, Waukesha, MI) or 16-row (LightSpeed, GE Healthcare) multidetector CT scanner with 0.625-mm or 2.5-mm collimation, respectively. Sagittal and coronal reformations at 3-mm slice thicknesses were reconstructed. Images were viewed on PACS and interpreted in consensus by a musculoskeletal radiology research fellow (H.S.) and a board-certified musculoskeletal radiologist (E.Y.C.) who were blinded to patient demographics during interpretation. The presence of CPPD crystal deposition in the SC joint was recorded when there was linear, curvilinear, or discrete mottled foci of highattenuating material (Fig. 1) [1]. Each side was independently evaluated, and the coronal plane was primarily used when available as it best demonstrated the articular surfaces and intraarticular disk as described in a previous study [9]. However, on examinations that did not have a coronal reconstruction plane, axial images were primarily used.
In addition to presence of calcification, presence and severity of osteoarthritis were graded according to the Kellgren–Lawrence (KL) scale [15]. Of note, we had previously performed a study on atlantoaxial CPPD crystal deposition on this same sample, and the prior results were included in this current analysis [1].
2.2. Statistical analysis Statistical analyses were performed in R [R version 2.15.1 (2012), R Foundation for Statistical Computing, Vienna, Austria]. The study sample was described. A χ 2 test of independence was used to evaluate symmetry of SC joint calcification. Univariate logistic regression was used to evaluate the relationship between SC joint calcification and age. Multivariate logistic regression was used to evaluate the relationship between SC joint calcification and age, gender, osteoarthritis, and atlantoaxial CPPD crystal deposition.
3. Results 3.1. Population characteristics The 209 patients included in the present study consisted of 129 males (median age, 49years; range, 19–98) and 80 females (median age, 65 years; range, 18–98). In our samples, the number of men outnumbered the number of women, and the women were significantly older than the men. Age and sex distributions are shown in Fig. 3 and Table 1.
Fig. 1. Examples of SCJ CPPD crystal deposition: (A) Axial CT image shows mottled high-attenuation CPPD crystal deposition in the capsule and cartilage of the SCJ in an 85-year-old woman (A) and in a 69-year-old woman (B). (C) Axial CT image shows curvilinear high-attenuation CPPD crystal deposition in the capsule and cartilage of the SCJ in a 61-year-old man. (D) Axial CT image shows linear high-attenuation CPPD crystal deposition in the capsule and cartilage of the SCJ in a 50-year-old man.
Please cite this article as: Shirazian H, et al, Prevalence of sternoclavicular joint calcium pyrophosphate dihydrate crystal deposition on computed tomography, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.02.016
H. Shirazian et al. / Clinical Imaging xxx (2014) xxx–xxx
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Table 1 Patient demographics and results Age range
Number of patients
Percentage of calcification
b20 20–29 30–39 40–49 50–59 60–69 70–79 80–89 90–99
2 38 23 27 43 14 25 25 12
0 (0/0) 0 (0/0) 0 (0/0) 1/27 (3.7%) 5/43(11.62%) 5/14 (35.7%) 7/25 (28%) 10/25 (40%) 8/12 (66.6%)
(1 M, 1 F) (30 M, 8 F) (17 M, 6 F) (21 M, 6 F) (32 M, 11 F) (8 M, 6 F) (10 M, 15 F) (11 M, 14 F) (2 M, 10 F)
M denotes males; F denotes females. Numbers in parentheses indicate patients with calcification over total number in age group.
Fig. 2. Logistic regression plot of age versus estimated probability of SCJ calcification. Each blue triangle represents the age of a subject in the sample who does not have calcification. Each red triangle represents the age of a subject in the sample who does have calcification. Age was a significant predictor of CPPD crystal deposition prevalence (logistic regression coefficient, Pb.0001). Prevalence of CPPD crystal deposition is low until about the age of 60years and rapidly increases thereafter.
3.2. SC CPPD crystal deposition Thirty-six (22 woman and 14 men) of the 209 patients had calcification in either one or both SC joints. Of these 36, 27 demonstrated bilateral involvement, while 9 demonstrated unilateral involvement. A χ2 test of independence confirmed that calcification is strongly symmetric: much more likely to be present or not present on both sides rather than one side (Pb.0001). Due to this strong symmetry, the remaining analysis considers overall calcification (presence of calcification on either side) as unilateral analysis results would be very similar. Age was a significant predictor of CPPD crystal deposition prevalence (logistic regression coefficient, Pb.0001). Mean age of patients with CPPD crystal deposition was 76years (standard deviation, 16years) compared with mean age of patients without CPPD crystal deposition at 50years (standard deviation, 20years). Fig. 2 shows that CPPD crystal
Fig. 3. Number of patients and age distribution of our sample by gender. Men were higher in number (129 patients) than women (80 patients). Also of note, women were disproportionately older in age (men’s mean age, 49years; women’s mean age, 65years).
deposition is low until about the age of 60years and that prevalence rapidly increases thereafter. Presence and severity of osteoarthritis were also highly symmetric. For instance, KL grade 0 was seen symmetrically in 161 patients, and KL grade 1 osteoarthritis was seen symmetrically in 27 patients. Multivariate logistic regression analysis demonstrated a statistically significant association between the presence of osteoarthritis (KL grade 1 and higher) and the presence of CPPD crystal deposition in SC joint (coefficient, P=.024). In addition, there was a significant association between CPPD crystal deposition in the SC and atlantoaxial joints (coefficient, P=.006). Gender was not a significant predictor of CPPD crystal deposition.
4. Discussion In this study, we demonstrated that the prevalence of calcium CPPD crystal deposition in the SC joint is significant in the study population. We also have shown that, with advancing age, the prevalence of osteoarthritis and CPPD crystal deposition in the SC joint increases. Furthermore, there is an increase in the prevalence of CPPD crystal deposition after the age of 60years. A prior study on this same population was performed in 2013 [1] and demonstrated a high frequency of CPPD crystal deposition in the atlantoaxial joint. We used these data to evaluate the association of CPPD crystal deposition in the SC joint and that in the atlantoaxial region and have shown that there is a significant association between these. Both osteoarthritis and CPPD crystal deposition in the SC joints were highly symmetric with similar severity. We also confirmed that CPPD crystal deposition in the SC joint was significantly associated with osteoarthritis as a separate predictor from age and atlantoaxial CPPD crystal deposition. However, both osteoarthritis and CPPD crystal deposition increased independently with age. Although CPPD crystal deposition is generally asymptomatic, it can cause synovitis and produce pain and swelling in the SC joint. SC joint swelling can also be observed in septic arthritis, particularly in highrisk patients such as intravenous drug users, diabetics, and patients with indwelling subclavian catheters. Important in the diagnosis of inflammatory arthritis due to CPPD crystal deposition is the presence of crystals [20]. The results of our study show that the prevalence of crystals increases with age, and therefore, it is important to also utilize other criteria, such as inflammatory markers in the blood. Prior studies have not focused on the prevalence of CPPD crystal deposition in the SC joint, and the available literature emphasized that peripheral articulations are affected more often than axial articulations. The knee is the most targeted site, with reported prevalences as high as 3.7% in those aged 55–59years, 17.5% in those aged 80– 84years [16], and 44% in those aged over 84years [17]. However, our recent study of the atlantoaxial region and this study of the SC joint indicate that the axial articulations are also frequently affected by CPPD deposition.
Please cite this article as: Shirazian H, et al, Prevalence of sternoclavicular joint calcium pyrophosphate dihydrate crystal deposition on computed tomography, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.02.016
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Some limitations of the study are acknowledged. Our study population included patients presenting for acute trauma and is not necessarily representative of the general population. The number of men outnumbered the number of women (129 versus 80), and men were younger. Also, CT scanning of the cervical spine and head as part of our routine trauma protocol does not show the SC joint clearly. Furthermore, although CT scanning is a helpful tool for detection of small calcifications, some reports indicate that ultrasonography appears to be more sensitive than CT scanning in revealing chondrocalcinosis [18], and histology is more sensitive than CT scanning in confirming CPPD crystal deposition [19]. Histologic analysis was not performed such that confirmation of the crystalline nature of the calcification was not obtained. However, the appearance of the calcification in the SC joints of our patients was identical to that related to CPPD crystal deposition at other sites. Thus, it was assumed that chondrocalcinosis was due to CPPD crystal deposition. In conclusion, this study demonstrated that there is a significant prevalence of CPPD crystal deposition in the SC joint. We confirmed that CPPD crystal deposition is highly associated with advancing age and osteoarthritis and is coincident with CPPD crystal deposition in the other regions such as the atlantoaxial region.
[6] [7] [8] [9]
[10] [11] [12]
[13]
[14] [15] [16]
[17]
References [18] [1] Chang EY, Lim WY, Wolfson T, Gamst AC, Chung CB, Bae WC, Resnick DL. Frequency of atlantoaxial calcium pyrophosphate dihydrate deposition at CT. Radiology 2013;269(2):519–24. [2] Resnick D. Diagnosis of bone and joint disorders. 4th ed. Philadelphia: Saunders; 2002. [3] De Marco G, Rampini C, Ferri E, Sinigaglia L. A rare case of chondrocalcinosis in the left sterno-clavicular joint. Rheumatology (Oxford) 2011;50(12):2317–8. [4] Pascual E. The diagnosis of gout and CPPD crystal arthropathy. Br J Rheumatol 1996;35(4):306–8. [5] Abreu M, Johnson K, Chung CB, De Lima Jr JE, Trudell D, Terkeltaub R, Pe S, Resnick D. Calcification in calcium pyrophosphate dihydrate (CPPD) crystalline deposits in
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the knee: anatomic, radiographic, MR imaging, and histologic study in cadavers. Skeletal Radiol 2004;33(7):392–8. Resnik CS, Resnick D. Crystal deposition disease. Semin Arthritis Rheum 1983;12 (4):390–403. Steinbach LS, Resnick D. Calcium pyrophosphate dihydrate crystal deposition disease revisited. Radiology 1996;200(1):1–9. Thongngarm T, McMurray RW. Osteoarthritis of the sternoclavicular joint. J Clin Rheumatol 2000;6(5):269–71. Restrepo CS, Martinez S, Lemos DF, Washington L, McAdams HP, Vargas D, Lemos JA, Carrillo JA, Diethelm L. Imaging appearances of the sternum and sternoclavicular joints. Radiographics 2009;29(3):839–59. Brossmann J, Stabler A, Preidler KW, Trudell D, Resnick D. Sternoclavicular joint: MR imaging—anatomic correlation. Radiology 1996;198(1):193–8. Resnick D, Niwayama G. Diagnosis of bone and joint disorders: with emphasis on articular abnormalities. Philadelphia: Saunders; 1981. Resnick D, Niwayama G, Goergen TG, Utsinger PD, Shapiro RF, Haselwood DH, Wiesner KB. Clinical, radiographic and pathologic abnormalities in calcium pyrophosphate dihydrate deposition disease (CPPD): pseudogout. Radiology 1977;122(1):1–15. Resnik CS, Miller BW, Gelberman RH, Resnick D. Hand and wrist involvement in calcium pyrophosphate dihydrate crystal deposition disease. J Hand Surg Am 1983;8(6):856–63. Richman KM, Boutin RD, Vaughan LM, Haghighi P, Resnick D. Tophaceous pseudogout of the sternoclavicular joint. AJR Am J Roentgenol 1999;172(6):1587–9. Kellgren JH, Lawrence JS. Radiological assessment of osteo-arthrosis. Ann Rheum Dis 1957;16(4):494–502. Neame RL, Carr AJ, Muir K, Doherty M. UK community prevalence of knee chondrocalcinosis: evidence that correlation with osteoarthritis is through a shared association with osteophyte. Ann Rheum Dis 2003;62(6):513–8. Wilkins E, Dieppe P, Maddison P, Evison G. Osteoarthritis and articular chondrocalcinosis in the elderly. Ann Rheum Dis 1983;42(3):280–4. Barskova VG, Kudaeva FM, Bozhieva LA, Smirnov AV, Volkov AV, Nasonov EL. Comparison of three imaging techniques in diagnosis of chondrocalcinosis of the knees in calcium pyrophosphate deposition disease. Rheumatology (Oxford) 2013;52(6):1090–4. Kakitsubata Y, Boutin RD, Theodorou DJ, Kerr RM, Steinbach LS, Chan KK, Pathria MN, Haghighi P, Resnick D. Calcium pyrophosphate dihydrate crystal deposition in and around the atlantoaxial joint: association with type 2 odontoid fractures in nine patients. Radiology 2000;216(1):213–9. Sternheim A, Chechik O, Freedman Y, Steinberg EL. Transient sternoclavicular joint arthropathy, a self-limited disease. J Shoulder Elbow Surg 2013. http://dx.doi.org/ 10.1016/j.jse.2013.08.013 [pii: S1058–2746(13)00441–2].
Please cite this article as: Shirazian H, et al, Prevalence of sternoclavicular joint calcium pyrophosphate dihydrate crystal deposition on computed tomography, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.02.016
Contents lists available at ScienceDirect
Clinical Imaging journal homepage: http://www.clinicalimaging.org
Prevalence of sternoclavicular joint calcium pyrophosphate dihydrate crystal deposition on computed tomography☆,☆☆ Hoda Shirazian a,⁎, Eric Y. Chang b, a, Tanya Wolfson a, Anthony C. Gamst a, Christine B. Chung b, a, Donald L. Resnick a a b
Department of Radiology, University of California, San Diego Medical Center Department of Radiology, VA San Diego Healthcare System
a r t i c l e
i n f o
Article history: Received 17 September 2013 Received in revised form 3 February 2014 Accepted 21 February 2014 Available online xxxx Keywords: CPPD Calcium pyrophosphate dihydrate Crystal deposition Sternoclavicular joint Computed tomography
a b s t r a c t We sought to determine the prevalence of sternoclavicular (SC) joint calcium pyrophosphate dihydrate (CPPD) crystal deposition and its association with age, osteoarthritis, and atlantoaxial CPPD crystal deposition. In 209 consecutive patients, computed tomographic examinations of the cervical spine were retrospectively reviewed. Overall prevalence of CPPD crystal deposition in the SC joint was 17.2% (36/209), which increased with age (Pb.0001). There was also a significant association between SC CPPD and osteoarthritis (P=.024) as well as atlantoaxial joint CPPD crystal deposition (P=.006).
1. Introduction Calcium pyrophosphate dihydrate (CPPD) crystal deposition can occur in the following three forms: hereditary, sporadic, or associated with other disorders such as metabolic and degenerative joint diseases [1,2]. CPPD crystals are usually observed bilaterally and symmetrically and are polyarticular in distribution [3,4]. Crystals may be apparent in cartilage (i.e., chondrocalcinosis), capsule, tendons, synovium, ligaments, bursae, and soft tissues [2]. Intraarticular chondrocalcinosis can be detected in both hyaline cartilage and fibrocartilage [1,2,5,6]. Calcification within fibrocartilage tends to appear thick and shaggy with irregular radiodense areas, particularly within the central aspect of the joint cavity. Calcification within hyaline cartilage has a thin linear appearance, paralleling the subjacent subchondral bone [2,6]. Previous studies have indicated that the prevalence of CPPD crystal deposition increases with age [5]. Although CPPD crystal deposition generally is clinically asymptomatic, symptoms such as acute or chronic arthritis, pain, stiffness, swelling, and decreased range of motion have been observed [6–8]. In the sternoclavicular (SC) joint, joint space narrowing and bone sclerosis in cases of CPPD crystal deposition
© 2014 Elsevier Inc. All rights reserved.
resemble osteoarthritis [9]. Additionally, however, calcification in hyaline cartilage or fibrocartilage, or both, may be evident, and perforation of the intraarticular disk is reported [10]. There are extensive studies about CPPD crystal deposition that have emphasized the importance of monitoring this condition [2,5,7,10–14]. Furthermore, a recent study has confirmed an increased prevalence of CPPD crystal deposition in the atlantoaxial joint when compared with reported data and has found a positive correlation with age and retroodontoid soft tissue thickness [1]. To our knowledge, this is the first study in which the prevalence of CPPD crystal deposition in the SC joint is examined. To date, only a few case reports on this subject have been reported, which have focused on associated symptoms such as tenderness and swelling of the SC joint due to compression from the calcified mass [3,14]. The purpose of this study was to (a) determine the prevalence of SC joint CPPD crystal deposition in a population of patients undergoing computed tomographic (CT) scanning for assessment of acute trauma and (b) to determine the association of SC joint CPPD crystal deposition with age, osteoarthritis, and atlantoaxial CPPD crystal deposition. 2. Material and methods
☆ Work performed at University of California, San Diego Medical Center. ☆☆ Eric Y. Chang, M.D., graciously acknowledges salary support from a VA CSR&D Career Development Award (5IK2CX000749). ⁎ Corresponding author. 8899 University center Lane, suit 370, San Diego, CA 92122. Tel.: +1 858 246 1011; fax: +1 858 552 9126. E-mail address: [email protected] (H. Shirazian).
Our institutional review board approved this retrospective, HIPAAcompliant study with an exemption of informed consent. We used our picture archive and communication system (PACS) to search the medical records of all patients who were admitted to our Level I trauma center
0899-7071/$ – see front matter © 2014 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.clinimag.2014.02.016
Please cite this article as: Shirazian H, et al, Prevalence of sternoclavicular joint calcium pyrophosphate dihydrate crystal deposition on computed tomography, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.02.016
2
H. Shirazian et al. / Clinical Imaging xxx (2014) xxx–xxx
(both trauma triage and emergency room cases) between January 1, 2010, and March 31, 2010. Trauma patients underwent CT scanning of both the head and the cervical spine as part of our routine trauma protocol. As part of our search criteria, cases were included if images of the cervical spine and/or thorax were available. With this protocol in place, our search yielded 521 patients that had received, at the minimum, CT imaging of the cervical spine and head. Of the 521, 304 patients were excluded because the SC joint was not entirely included in the field of view, 5 patients were excluded because the age of the patient was not documented, and 3 patients were excluded due to metallic artifact. In total, 209 patients were included in our study. 2.1. Image acquisition and analysis Patients underwent imaging from the occiput to T4 with either a 64row (CT750 HD, GE Healthcare, Waukesha, MI) or 16-row (LightSpeed, GE Healthcare) multidetector CT scanner with 0.625-mm or 2.5-mm collimation, respectively. Sagittal and coronal reformations at 3-mm slice thicknesses were reconstructed. Images were viewed on PACS and interpreted in consensus by a musculoskeletal radiology research fellow (H.S.) and a board-certified musculoskeletal radiologist (E.Y.C.) who were blinded to patient demographics during interpretation. The presence of CPPD crystal deposition in the SC joint was recorded when there was linear, curvilinear, or discrete mottled foci of highattenuating material (Fig. 1) [1]. Each side was independently evaluated, and the coronal plane was primarily used when available as it best demonstrated the articular surfaces and intraarticular disk as described in a previous study [9]. However, on examinations that did not have a coronal reconstruction plane, axial images were primarily used.
In addition to presence of calcification, presence and severity of osteoarthritis were graded according to the Kellgren–Lawrence (KL) scale [15]. Of note, we had previously performed a study on atlantoaxial CPPD crystal deposition on this same sample, and the prior results were included in this current analysis [1].
2.2. Statistical analysis Statistical analyses were performed in R [R version 2.15.1 (2012), R Foundation for Statistical Computing, Vienna, Austria]. The study sample was described. A χ 2 test of independence was used to evaluate symmetry of SC joint calcification. Univariate logistic regression was used to evaluate the relationship between SC joint calcification and age. Multivariate logistic regression was used to evaluate the relationship between SC joint calcification and age, gender, osteoarthritis, and atlantoaxial CPPD crystal deposition.
3. Results 3.1. Population characteristics The 209 patients included in the present study consisted of 129 males (median age, 49years; range, 19–98) and 80 females (median age, 65 years; range, 18–98). In our samples, the number of men outnumbered the number of women, and the women were significantly older than the men. Age and sex distributions are shown in Fig. 3 and Table 1.
Fig. 1. Examples of SCJ CPPD crystal deposition: (A) Axial CT image shows mottled high-attenuation CPPD crystal deposition in the capsule and cartilage of the SCJ in an 85-year-old woman (A) and in a 69-year-old woman (B). (C) Axial CT image shows curvilinear high-attenuation CPPD crystal deposition in the capsule and cartilage of the SCJ in a 61-year-old man. (D) Axial CT image shows linear high-attenuation CPPD crystal deposition in the capsule and cartilage of the SCJ in a 50-year-old man.
Please cite this article as: Shirazian H, et al, Prevalence of sternoclavicular joint calcium pyrophosphate dihydrate crystal deposition on computed tomography, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.02.016
H. Shirazian et al. / Clinical Imaging xxx (2014) xxx–xxx
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Table 1 Patient demographics and results Age range
Number of patients
Percentage of calcification
b20 20–29 30–39 40–49 50–59 60–69 70–79 80–89 90–99
2 38 23 27 43 14 25 25 12
0 (0/0) 0 (0/0) 0 (0/0) 1/27 (3.7%) 5/43(11.62%) 5/14 (35.7%) 7/25 (28%) 10/25 (40%) 8/12 (66.6%)
(1 M, 1 F) (30 M, 8 F) (17 M, 6 F) (21 M, 6 F) (32 M, 11 F) (8 M, 6 F) (10 M, 15 F) (11 M, 14 F) (2 M, 10 F)
M denotes males; F denotes females. Numbers in parentheses indicate patients with calcification over total number in age group.
Fig. 2. Logistic regression plot of age versus estimated probability of SCJ calcification. Each blue triangle represents the age of a subject in the sample who does not have calcification. Each red triangle represents the age of a subject in the sample who does have calcification. Age was a significant predictor of CPPD crystal deposition prevalence (logistic regression coefficient, Pb.0001). Prevalence of CPPD crystal deposition is low until about the age of 60years and rapidly increases thereafter.
3.2. SC CPPD crystal deposition Thirty-six (22 woman and 14 men) of the 209 patients had calcification in either one or both SC joints. Of these 36, 27 demonstrated bilateral involvement, while 9 demonstrated unilateral involvement. A χ2 test of independence confirmed that calcification is strongly symmetric: much more likely to be present or not present on both sides rather than one side (Pb.0001). Due to this strong symmetry, the remaining analysis considers overall calcification (presence of calcification on either side) as unilateral analysis results would be very similar. Age was a significant predictor of CPPD crystal deposition prevalence (logistic regression coefficient, Pb.0001). Mean age of patients with CPPD crystal deposition was 76years (standard deviation, 16years) compared with mean age of patients without CPPD crystal deposition at 50years (standard deviation, 20years). Fig. 2 shows that CPPD crystal
Fig. 3. Number of patients and age distribution of our sample by gender. Men were higher in number (129 patients) than women (80 patients). Also of note, women were disproportionately older in age (men’s mean age, 49years; women’s mean age, 65years).
deposition is low until about the age of 60years and that prevalence rapidly increases thereafter. Presence and severity of osteoarthritis were also highly symmetric. For instance, KL grade 0 was seen symmetrically in 161 patients, and KL grade 1 osteoarthritis was seen symmetrically in 27 patients. Multivariate logistic regression analysis demonstrated a statistically significant association between the presence of osteoarthritis (KL grade 1 and higher) and the presence of CPPD crystal deposition in SC joint (coefficient, P=.024). In addition, there was a significant association between CPPD crystal deposition in the SC and atlantoaxial joints (coefficient, P=.006). Gender was not a significant predictor of CPPD crystal deposition.
4. Discussion In this study, we demonstrated that the prevalence of calcium CPPD crystal deposition in the SC joint is significant in the study population. We also have shown that, with advancing age, the prevalence of osteoarthritis and CPPD crystal deposition in the SC joint increases. Furthermore, there is an increase in the prevalence of CPPD crystal deposition after the age of 60years. A prior study on this same population was performed in 2013 [1] and demonstrated a high frequency of CPPD crystal deposition in the atlantoaxial joint. We used these data to evaluate the association of CPPD crystal deposition in the SC joint and that in the atlantoaxial region and have shown that there is a significant association between these. Both osteoarthritis and CPPD crystal deposition in the SC joints were highly symmetric with similar severity. We also confirmed that CPPD crystal deposition in the SC joint was significantly associated with osteoarthritis as a separate predictor from age and atlantoaxial CPPD crystal deposition. However, both osteoarthritis and CPPD crystal deposition increased independently with age. Although CPPD crystal deposition is generally asymptomatic, it can cause synovitis and produce pain and swelling in the SC joint. SC joint swelling can also be observed in septic arthritis, particularly in highrisk patients such as intravenous drug users, diabetics, and patients with indwelling subclavian catheters. Important in the diagnosis of inflammatory arthritis due to CPPD crystal deposition is the presence of crystals [20]. The results of our study show that the prevalence of crystals increases with age, and therefore, it is important to also utilize other criteria, such as inflammatory markers in the blood. Prior studies have not focused on the prevalence of CPPD crystal deposition in the SC joint, and the available literature emphasized that peripheral articulations are affected more often than axial articulations. The knee is the most targeted site, with reported prevalences as high as 3.7% in those aged 55–59years, 17.5% in those aged 80– 84years [16], and 44% in those aged over 84years [17]. However, our recent study of the atlantoaxial region and this study of the SC joint indicate that the axial articulations are also frequently affected by CPPD deposition.
Please cite this article as: Shirazian H, et al, Prevalence of sternoclavicular joint calcium pyrophosphate dihydrate crystal deposition on computed tomography, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.02.016
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Some limitations of the study are acknowledged. Our study population included patients presenting for acute trauma and is not necessarily representative of the general population. The number of men outnumbered the number of women (129 versus 80), and men were younger. Also, CT scanning of the cervical spine and head as part of our routine trauma protocol does not show the SC joint clearly. Furthermore, although CT scanning is a helpful tool for detection of small calcifications, some reports indicate that ultrasonography appears to be more sensitive than CT scanning in revealing chondrocalcinosis [18], and histology is more sensitive than CT scanning in confirming CPPD crystal deposition [19]. Histologic analysis was not performed such that confirmation of the crystalline nature of the calcification was not obtained. However, the appearance of the calcification in the SC joints of our patients was identical to that related to CPPD crystal deposition at other sites. Thus, it was assumed that chondrocalcinosis was due to CPPD crystal deposition. In conclusion, this study demonstrated that there is a significant prevalence of CPPD crystal deposition in the SC joint. We confirmed that CPPD crystal deposition is highly associated with advancing age and osteoarthritis and is coincident with CPPD crystal deposition in the other regions such as the atlantoaxial region.
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Please cite this article as: Shirazian H, et al, Prevalence of sternoclavicular joint calcium pyrophosphate dihydrate crystal deposition on computed tomography, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.02.016
