Ultrasound of the Scrotum

Seminars in Ultrasound, CT and MRI

Volumn 28, Issue 4, 2007, Pages 225-248

  Pearl, Monica Smith ^a   Hill, Michael C ^a  

^a GEORGE WASHINGTON UNIVERSITY HOSPITAL   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ANDROGEN;

ADRENAL CORTEX TUMOR; ANATOMICAL VARIATION; ARTICLE; CRYPTORCHISM; CYSTIC DYSPLASIA; EPIDIDYMAL CYST; EPIDIDYMIS DISEASE; EPIDIDYMITIS; FIBROUS PSEUDOTUMOR; HUMAN; HYDROCELE; INGUINAL HERNIA; MALE; MALE INFERTILITY; METASTASIS; NON SEMINOMATOUS GERMINOMA; PRIORITY JOURNAL; SARCOIDOSIS; SCROTUM DISORDER; SCROTUM INJURY; SEMINOMA; SURGICAL TECHNIQUE; TESTICULAR CALCIFICATION; TESTICULAR MICROLITHIASIS; TESTIS TORSION; TUBULAR ECTASIA; ULTRASOUND; VARICOCELE;

GENITAL DISEASES, MALE; HUMANS; MALE; SCROTUM;

EID: 34547497535     PISSN: 08872171     EISSN: None     Source Type: Journal    
DOI: 10.1053/j.sult.2007.05.001     Document Type: Article

References (129)

1. Martin B., and Conte J. Ultrasonography of the acute scrotum. J Clin Ultrasound 15 1 (1987) 37-44
2. Dogra V.S., Gottlieb R.H., Oka M., et al. Sonography of the scrotum. Radiology 227 1 (2003) 18-36
3. Tessler F.N., Tublin M.E., and Rifkin M.D. Ultrasound assessment of testicular and paratesticular masses. J Clin Ultrasound 24 8 (1996) 423-436
4. Sudakoff G.S., Quiroz F., Karcaaltincaba M., et al. Scrotal ultrasonography with emphasis on the extratesticular space: anatomy, embryology, and pathology. Ultrasound Q 18 4 (2002) 255-273
5. Casalino D.D., and Kim R. Clinical importance of a unilateral striated pattern seen on sonography of the testicle. AJR Am J Roentgenol 178 4 (2002) 927-930
6. Fakhry J., Khoury A., and Barakat K. The hypoechoic band: a normal finding on testicular sonography. AJR Am J Roentgenol 153 2 (1989) 321-323
7. Black J.A., and Patel A. Sonography of the normal extratesticular space. AJR Am J Roentgenol 167 2 (1996) 503-506
8. Puttemans T., Delvigne A., and Murillo D. Normal and variant appearances of the adult epididymis and vas deferens on high-resolution sonography. J Clin Ultrasound 34 8 (2006) 385-392
9. Horstman W.G. Scrotal imaging. Urol Clin North Am 24 3 (1997) 653-671
10. Johnson K.A., and Dewbury K.C. Ultrasound imaging of the appendix testis and appendix epididymis. Clin Radiol 51 5 (1996) 335-337
11. Gooding G.A. Sonography of the spermatic cord. AJR Am J Roentgenol 151 4 (1988) 721-724
12. Middleton W.D., Thorne D.A., and Melson G.L. Color Doppler ultrasound of the normal testis. AJR Am J Roentgenol 152 2 (1989) 293-297
13. Middleton W.D., and Bell M.W. Analysis of intratesticular arterial anatomy with emphasis on transmediastinal arteries. Radiology 189 1 (1993) 157-160
14. Pepe P., Panella P., Pennisi M., et al. Does color Doppler sonography improve the clinical assessment of patients with acute scrotum?. Eur J Radiol 60 1 (2006) 120-124
15. Moudy P.C., and Makhija J.S. Ultrasonic demonstration of a non-palpable testicular tumor. J Clin Ultrasound 11 1 (1983) 54-55
16. Schwerk W.B., Schwerk W.N., and Rodeck G. Testicular tumors: prospective analysis of real-time US patterns and abdominal staging. Radiology 164 2 (1987) 369-374
17. Carmignani L., Gadda F., Gazzano G., et al. High incidence of benign testicular neoplasms diagnosed by ultrasound. J Urol 170 5 (2003) 1783-1786
18. Carroll B.A., and Gross D.M. High-frequency scrotal sonography. AJR Am J Roentgenol 140 3 (1983) 511-515
19. Powell T.M., and Tarter T.H. Management of nonpalpable incidental testicular masses. J Urol 176 1 (2006) 96-98 discussion 99
20. Glazer H.S., Lee J.K., Melson G.L., et al. Sonographic detection of occult testicular neoplasms. AJR Am J Roentgenol 138 4 (1982) 673-675
21. Stoll S., Goldfinger M., Rothberg R., et al. Incidental detection of impalpable testicular neoplasm by sonography. AJR Am J Roentgenol 146 2 (1986) 349-350
22. Kirschling R.J., Kvols L.K., Charboneau J.W., et al. High-resolution ultrasonographic and pathologic abnormalities of germ cell tumors in patients with clinically normal testes. Mayo Clin Proc 58 10 (1983) 648-653
23. Grantham J.G., Charboneau J.W., James E.M., et al. Testicular neoplasms: 29 tumors studied by high-resolution US. Radiology 157 3 (1985) 775-780
24. Frates M.C., Benson C.B., DiSalvo D.N., et al. Solid extratesticular masses evaluated with sonography: pathologic correlation. Radiology 204 1 (1997) 43-46
25. Beccia D.J., Krane R.J., and Olsson C.A. Clinical management of non-testicular intrascrotal tumors. J Urol 116 4 (1976) 476-479
26. Fernandez-Perez G.C., Tardaguila F.M., Velasco M., et al. Radiologic findings of segmental testicular infarction. AJR Am J Roentgenol 184 5 (2005) 1587-1593
27. Horstman W.G., Melson G.L., Middleton W.D., et al. Testicular tumors: findings with color Doppler US. Radiology 185 3 (1992) 733-737
28. Luker G.D., and Siegel M.J. Pediatric testicular tumors: evaluation with gray-scale and color Doppler US. Radiology 191 2 (1994) 561-564
29. Cheville J.C. Classification and pathology of testicular germ cell and sex cord-stromal tumors. Urol Clin North Am 26 3 (1999) 595-609
30. Mostofi F.K., Davis Jr. J., and Rehm S. Tumours of the testis. IARC Sci Publ 111 (1994) 407-429
31. Benson C.B., Deligdish C.K., and Loughlin K.R. Sonographic detection of testicular plasmacytoma. J Clin Ultrasound 15 7 (1987) 490-493
32. Gierke C.L., King B.F., Bostwick D.G., et al. Large-cell calcifying Sertoli cell tumor of the testis: appearance at sonography. AJR Am J Roentgenol 163 2 (1994) 373-375
33. Shawker T.H., Javadpour N., O'Leary T., et al. Ultrasonographic detection of "burned-out" primary testicular germ cell tumors in clinically normal testes. J Ultrasound Med 2 10 (1983) 477-479
34. Emory T.H., Charboneau J.W., Randall R.V., et al. Occult testicular interstitial-cell tumor in a patient with gynecomastia: ultrasonic detection. Radiology 151 2 (1984) 474
35. Soria J.C., Durdux C., Chretien Y., et al. Malignant Leydig cell tumor of the testis associated with Klinefelter's syndrome. Anticancer Res 19 5C (1999) 4491-4494
36. Maizlin Z.V., Belenky A., Kunichezky M., et al. Leydig cell tumors of the testis: gray scale and color Doppler sonographic appearance. J Ultrasound Med 23 7 (2004) 959-964
37. Giglio M., Medica M., De Rose A.F., et al. Testicular sertoli cell tumours and relative sub-types. Analysis of clinical and prognostic features. Urol Int 70 3 (2003) 205-210
38. Young S., Gooneratne S., Straus F.H., et al. Feminizing Sertoli cell tumors in boys with Peutz-Jeghers syndrome. Am J Surg Pathol 19 1 (1995) 50-58
39. Proppe K.H., and Scully R.E. Large-cell calcifying Sertoli cell tumor of the testis. Am J Clin Pathol 74 5 (1980) 607-619
40. Noszian I.M., Balon R., Eitelberger F.G., et al. Bilateral testicular large-cell calcifying sertoli cell tumor and recurrent cardiac myxoma in a patient with Carney's complex. Pediatr Radiol 25 suppl 1 (1995) S236-S237
41. Carney J.A., Gordon H., Carpenter P.C., et al. The complex of myxomas, spotty pigmentation, and endocrine overactivity. Medicine (Baltimore) 64 4 (1985) 270-283
42. Washecka R., Dresner M.I., and Honda S.A. Testicular tumors in Carney's complex. J Urol 167 3 (2002) 1299-1302
43. Tepperman B.S., Gospodarowicz M.K., Bush R.S., et al. Non-Hodgkin lymphoma of the testis. Radiology 142 1 (1982) 203-208
44. Mazzu D., Jeffrey Jr. R.B., and Ralls P.W. Lymphoma and leukemia involving the testicles: findings on gray-scale and color Doppler sonography. AJR Am J Roentgenol 164 3 (1995) 645-647
45. Doll D.C., and Weiss R.B. Malignant lymphoma of the testis. Am J Med 81 3 (1986) 515-524
46. Moller M.B., d'Amore F., and Christensen B.E. Testicular lymphoma: a population-based study of incidence, clinicopathological correlations and prognosis. The Danish Lymphoma Study Group, LYFO. Eur J Cancer 30A 12 (1994) 1760-1764
47. Phillips G., Kumari-Subaiya S., and Sawitsky A. Ultrasonic evaluation of the scrotum in lymphoproliferative disease. J Ultrasound Med 6 4 (1987) 169-175
48. McDermott M.B., O'Briain D.S., Shiels O.M., et al. Malignant lymphoma of the epididymis. A case report of bilateral involvement by a follicular large cell lymphoma. Cancer 75 8 (1995) 2174-2179
49. Rayor R.A., Scheible W., Brock W.A., et al. High resolution ultrasonography in the diagnosis of testicular relapse in patients with acute lymphoblastic leukemia. J Urol 128 3 (1982) 602-603
50. Anghel G., Petti N., Remotti D., et al. Testicular plasmacytoma: report of a case and review of the literature. Am J Hematol 71 2 (2002) 98-104
51. Ferry J.A., Young R.H., and Scully R.E. Testicular and epididymal plasmacytoma: a report of 7 cases, including three that were the initial manifestation of plasma cell myeloma. Am J Surg Pathol 21 5 (1997) 590-598
52. Grignon D.J., Shum D.T., and Hayman W.P. Metastatic tumours of the testes. Can J Surg 29 5 (1986) 359-361
53. Johansson J.E., and Lannes P. Metastases to the spermatic cord, epididymis and testicles from carcinoma of the prostate-five cases. Scand J Urol Nephrol 17 2 (1983) 249-251
54. Bhatt S., Rubens D.J., and Dogra V.S. Sonography of benign intrascrotal lesions. Ultrasound Q 22 2 (2006) 121-136
55. Dogra V.S., Gottlieb R.H., Rubens D.J., et al. Benign intratesticular cystic lesions: US features. Radiographics 21 Spec No. (2001) S273-S281
56. Gooding G.A., Leonhardt W., and Stein R. Testicular cysts: US findings. Radiology 163 2 (1987) 537-538
57. Martinez-Berganza M.T., Sarria L., Cozcolluela R., et al. Cysts of the tunica albuginea: sonographic appearance. AJR Am J Roentgenol 170 1 (1998) 183-185
58. Hamm B., Fobbe F., and Loy V. Testicular cysts: differentiation with US and clinical findings. Radiology 168 1 (1988) 19-23
59. Nistal M., Iniguez L., and Paniagua R. Cysts of the testicular parenchyma and tunica albuginea. Arch Pathol Lab Med 113 8 (1989) 902-906
60. Poster R.B., Spirt B.A., Tamsen A., et al. Complex tunica albuginea cyst simulating an intratesticular lesion. Urol Radiol 13 2 (1991) 129-132
61. Loya A.G., Said J.W., and Grant E.G. Epidermoid cyst of the testis: radiologic-pathologic correlation. Radiographics 24 suppl 1 (2004) S243-S246
62. Atchley J.T., and Dewbury K.C. Ultrasound appearances of testicular epidermoid cysts. Clin Radiol 55 7 (2000) 493-502
63. Sanderson A.J., Birch B.R., and Dewbury K.C. Case report: multiple epidermoid cysts of the testes-the ultrasound appearances. Clin Radiol 50 6 (1995) 414-415
64. Stein M.M., Stein M.W., Cohen B.C., et al. Unusual sonographic appearance of an epidermoid cyst of the testis. J Ultrasound Med 18 10 (1999) 723-726
65. Brown D.L., Benson C.B., Doherty F.J., et al. Cystic testicular mass caused by dilated rete testis: sonographic findings in 31 cases. AJR Am J Roentgenol 158 6 (1992) 1257-1259
66. Weingarten B.J., Kellman G.M., Middleton W.D., et al. Tubular ectasia within the mediastinum testis. J Ultrasound Med 11 7 (1992) 349-353
67. Tartar V.M., Trambert M.A., Balsara Z.N., et al. Tubular ectasia of the testicle: sonographic and MR imaging appearance. AJR Am J Roentgenol 160 3 (1993) 539-542
68. Piotto L., LeQuesne G.W., Gent R., et al. Congenital cystic dysplasia of the rete testis. Pediatr Radiol 31 (2001) 724-726
69. Cast J.E., Nelson W.M., Early A.S., et al. Testicular microlithiasis: prevalence and tumor risk in a population referred for scrotal sonography. AJR Am J Roentgenol 175 6 (2000) 1703-1706
70. Janzen D.L., Mathieson J.R., Marsh J.I., et al. Testicular microlithiasis: sonographic and clinical features. AJR Am J Roentgenol 158 5 (1992) 1057-1060
71. Middleton W.D., Teefey S.A., and Santillan C.S. Testicular microlithiasis: prospective analysis of prevalence and associated tumor. Radiology 224 2 (2002) 425-428
72. Bennett H.F., Middleton W.D., Bullock A.D., et al. Testicular microlithiasis: US follow-up. Radiology 218 2 (2001) 359-363
73. Kragel P.J., Delvecchio D., Orlando R., et al. Ultrasonographic findings of testicular microlithiasis associated with intratubular germ cell neoplasia. Urology 37 1 (1991) 66-68
74. Zastrow S., Hakenberg O.W., and Wirth M.P. Significance of testicular microlithiasis. Urol Int 75 1 (2005) 3-7
75. Vachon L., Fareau G.E., Wilson M.G., et al. Testicular microlithiasis in patients with Down syndrome. J Pediatr 149 2 (2006) 233-236
76. Sakamoto H., Shichizyou T., Saito K., et al. Testicular microlithiasis identified ultrasonographically in Japanese adult patients: prevalence and associated conditions. Urology 68 3 (2006) 636-641
77. Kim B., Winter T.C., and Ryu J.A. Testicular microlithiasis: clinical significance and review of the literature. Eur Radiol 13 12 (2003) 2567-2576
78. Otite U., Webb J.A., Oliver R.T., et al. Testicular microlithiasis: is it a benign condition with malignant potential. Eur Urol 40 5 (2001) 538-542
79. Bach A.M., Hann L.E., Hadar O., et al. Testicular microlithiasis: what is its association with testicular cancer?. Radiology 220 1 (2001) 70-75
80. Eraso C.E., Vrachliotis T.G., and Cunningham J.J. Sonographic findings in testicular sarcoidosis simulating malignant nodule. J Clin Ultrasound 27 2 (1999) 81-83
81. Winter T.C., Keener T.S., and Mack L.A. Sonographic appearance of testicular sarcoid. J Ultrasound Med 14 2 (1995) 153-156
82. Avila N.A., Shawker T.S., Jones J.V., et al. Testicular adrenal rest tissue in congenital adrenal hyperplasia: serial sonographic and clinical findings. AJR Am J Roentgenol 172 5 (1999) 1235-1238
83. Vanzulli A., DelMaschio A., Paesano P., et al. Testicular masses in association with adrenogenital syndrome: US findings. Radiology 183 2 (1992) 425-429
84. Avila N.A., Premkumar A., Shawker T.H., et al. Testicular adrenal rest tissue in congenital adrenal hyperplasia: findings at Gray-scale and color Doppler US. Radiology 198 1 (1996) 99-104
85. Rosenfield A.T., Blair D.N., McCarthy S., et al. Society of Uroradiology Award paper. The pars infravaginalis gubernaculi: importance in the identification of the undescended testis. AJR Am J Roentgenol 153 4 (1989) 775-778
86. Friedland G.W., and Chang P. The role of imaging in the management of the impalpable undescended testis. AJR Am J Roentgenol 151 6 (1988) 1107-1111
87. Kolon T.F., Patel R.P., and Huff D.S. Cryptorchidism: diagnosis, treatment, and long-term prognosis. Urol Clin North Am 31 3 (2004) 469-480 viii-ix
88. Akin E.A., Khati N.J., and Hill M.C. Ultrasound of the scrotum. Ultrasound Q 20 4 (2004) 181-200
89. Weiss R.M., Carter A.R., and Rosenfield A.T. High resolution real-time ultrasonography in the localization of the undescended testis. J Urol 135 5 (1986) 936-938
90. Beomonte Zobel B., Vicentini C., Masciocchi C., et al. Magnetic resonance imaging in the localization of undescended abdominal testes. Eur Urol 17 2 (1990) 145-148
91. Kier R., McCarthy S., Rosenfield A.T., et al. Nonpalpable testes in young boys: evaluation with MR imaging. Radiology 169 2 (1988) 429-433
92. Oh C., Nisenbaum H.L., Langer J., et al. Sonographic demonstration, including color Doppler imaging, of recurrent sperm granuloma. J Ultrasound Med 19 5 (2000) 333-335
93. Dunner P.S., Lipsit E.R., and Nochomovitz L.E. Epididymal sperm granuloma simulating a testicular neoplasm. J Clin Ultrasound 10 7 (1982) 353-355
94. Ishizaka K., Kamai T., Gotoh S., et al. Epididymal sperm invasion apparently suggestive of a testicular tumor. Hinyokika Kiyo 40 2 (1994) 161-163
95. Makarainen H.P., Tammela T.L., Karttunen T.J., et al. Intrascrotal adenomatoid tumors and their ultrasound findings. J Clin Ultrasound 21 1 (1993) 33-37
96. Wernert N., Goebbels R., and Prediger L. Papillary cystadenoma of the epididymis. Case report and review of the literature. Pathol Res Pract 181 2 (1986) 260-264
97. Krainik A., Sarrazin J.L., Camparo P., et al. Fibrous pseudotumor of the epididymis: imaging and pathologic correlation. Eur Radiol 10 10 (2000) 1636-1638
98. Germaine P., and Simerman L.P. Fibrous pseudotumor of the scrotum. J Ultrasound Med 26 1 (2007) 133-138
99. Einstein D.M., Paushter D.M., Singer A.A., et al. Fibrotic lesions of the testicle: sonographic patterns mimicking malignancy. Urol Radiol 14 3 (1992) 205-210
100. Tobias-Machado M., Correa Lopes Neto A., Heloisa Simardi L., et al. Fibrous pseudotumor of tunica vaginalis and epididymis. Urology 56 4 (2000) 670-672
101. Smith F.J., Bilbey J.H., Filipenko J.D., et al. Testicular pseudotumor in the acquired immunodeficiency syndrome. Urology 45 3 (1995) 535-537
102. Pekindil G., Huseyin Atakan I., Kaya E., et al. Bilateral synchronous granulomatous orchitis: gray-scale and colour Doppler sonographic findings. Eur J Radiol 31 3 (1999) 201-203
103. Muttarak M., Peh W.C., Lojanapiwat B., et al. Tuberculous epididymitis and epididymo-orchitis: sonographic appearances. AJR Am J Roentgenol 176 6 (2001) 1459-1466
104. Chung J.J., Kim M.J., Lee T., et al. Sonographic findings in tuberculous epididymitis and epididymo-orchitis. J Clin Ultrasound 25 7 (1997) 390-394
105. Ozturk A., Ozturk E., Zeyrek F., et al. Comparison of brucella and non-specific epididymorchitis: gray scale and color Doppler ultrasonographic features. Eur J Radiol 56 2 (2005) 256-262
106. Basekim C.C., Kizilkaya E., Pekkafali Z., et al. Mumps epididymo-orchitis: sonography and color Doppler sonographic findings. Abdom Imaging 25 3 (2000) 322-325
107. Horstman W.G., Middleton W.D., and Melson G.L. Scrotal inflammatory disease: color Doppler US findings. Radiology 179 1 (1991) 55-59
108. Farriol V.G., Comella X.P., Agromayor E.G., et al. Gray-scale and power Doppler sonographic appearances of acute inflammatory diseases of the scrotum. J Clin Ultrasound 28 2 (2000) 67-72
109. Brown J.M., Hammers L.W., Barton J.W., et al. Quantitative Doppler assessment of acute scrotal inflammation. Radiology 197 2 (1995) 427-431
110. Cook J.L., and Dewbury K. The changes seen on high-resolution ultrasound in orchitis. Clin Radiol 55 1 (2000) 13-18
111. Mevorach R.A., Lerner R.M., Dvoretsky P.M., et al. Testicular abscess: diagnosis by ultrasonography. J Urol 136 6 (1986) 1213-1216
112. Jafri S.Z., Bree R.L., Madrazo B.L., et al. Sonography of large scrotal infections. J Clin Ultrasound 19 7 (1991) 413-418
113. Buckley J.C., and McAninch J.W. Use of ultrasonography for the diagnosis of testicular injuries in blunt scrotal trauma. J Urol 175 1 (2006) 175-178
114. Learch T.J., Hansch L.P., and Ralls P.W. Sonography in patients with gunshot wounds of the scrotum: imaging findings and their value. AJR Am J Roentgenol 165 4 (1995) 879-883
115. Cohen H.L., Shapiro M.L., Haller J.O., et al. Sonography of intrascrotal hematomas simulating testicular rupture in adolescents. Pediatr Radiol 22 4 (1992) 296-297
116. Gordon L.M., Stein S.M., and Ralls P.W. Traumatic epididymitis: evaluation with color Doppler sonography. AJR Am J Roentgenol 166 6 (1996) 1323-1325
117. Gooding G.A., Leonhardt W.C., Marshall G., et al. Cholesterol crystals in hydroceles: sonographic detection and possible significance. AJR Am J Roentgenol 169 2 (1997) 527-529
118. Meacham R.B., Townsend R.R., Rademacher D., et al. The incidence of varicoceles in the general population when evaluated by physical examination, gray scale sonography and color Doppler sonography. J Urol 151 6 (1994) 1535-1538
119. Gonda Jr. R.L., Karo J.J., Forte R.A., et al. Diagnosis of subclinical varicocele in infertility. AJR Am J Roentgenol 148 1 (1987) 71-75
120. Mehta A.L., and Dogra V.S. Intratesticular varicocele. J Clin Ultrasound 26 1 (1998) 49-51
121. Pierik F.H., Dohle G.R., van Muiswinkel J.M., et al. Is routine scrotal ultrasound advantageous in infertile men?. J Urol 162 5 (1999) 1618-1620
122. Rifkin M.D., Foy P.M., Kurtz A.B., et al. The role of diagnostic ultrasonography in varicocele evaluation. J Ultrasound Med 2 6 (1983) 271-275
123. Graif M., Hauser R., Hirshebein A., et al. Varicocele and the testicular-renal venous route: hemodynamic Doppler sonographic investigation. J Ultrasound Med 19 9 (2000) 627-631
124. Kocakoc E., Serhatlioglu S., Kiris A., et al. Color Doppler sonographic evaluation of inter-relations between diameter, reflux and flow volume of testicular veins in varicocele. Eur J Radiol 47 3 (2003) 251-256
125. Tasci A.I., Resim S., Caskurlu T., et al. Color Doppler ultrasonography and spectral analysis of venous flow in diagnosis of varicocele. Eur Urol 39 3 (2001) 316-321
126. Kessler A., Meirsdorf S., Graif M., et al. Intratesticular varicocele: gray scale and color Doppler sonographic appearance. J Ultrasound Med 24 12 (2005) 1711-1716
127. Atasoy C., and Fitoz S. Gray-scale and color Doppler sonographic findings in intratesticular varicocele. J Clin Ultrasound 29 7 (2001) 369-373
128. Eftekhari F., and Smith J.K. Sonography of the scrotum after orchiectomy: normal and abnormal findings. AJR Am J Roentgenol 160 3 (1993) 543-547
129. Furtschegger A., Sandbichler P., Judmaier W., et al. Sonography in the postoperative evaluation of laparoscopic inguinal hernia repair. J Ultrasound Med 14 9 (1995) 679-684