Acta Veterinaria Scandinavica 2007, 49:39 http://www.actavetscand.com/content/49/1/39 FHiigstuorpeat2hology of disc no. 6 (C7–T1) from Dog no. 10 Histopathology of disc no. 6 (C7–T1) from Dog no. 10. Cal- cium deposits (arrows) are seen multifocally occupying less than half of the area of the nucleus pulposus (Np): 'slight' degree of calcification (1). Af = annulus fibrosus. Von Kossa; Bar = 1.6 mm. SEVERE (Figure 4): - widespread or total calcification of the nucleus pulposus - single or multiple large foci of calcification within the annulus fibrosus - broad calcified ring, continuous or discontinuous, either surrounding the nucleus pulposus or localised within the annulus fibrosus If two or more sections of the same disc were read to have different degrees of calcification, the section with the most severe degree of calcification determined the evaluation of that disc. Radiographs and histological sections were evaluated independently. Results At the radiographic examination, calcification was found in 148 (28.5%) of the 520 discs. Of all affected discs, a severe degree of calcification was found in 15, a moderate degree in 43 and a slight degree in 90 discs. Calcified discs were identified in 18 (90.0%) of the dogs and the number of calcified discs in each affected dog ranged from one (dog no. 19) to 20 (dog no. 15). FHiigstuorpeat3hology of disc no 10 (T4–5) from Dog no. 10 Histopathology of disc no 10 (T4–5) from Dog no. 10. Cal- cium deposits (arrows) form a thin discontinuous ring sur- rounding the nucleus pulposus (Np), with one focus extending into the annulus fibrosus: 'moderate' degree of cal- cification (2). Af = annulus fibrosus. Von Kossa; Bar = 1.6 mm. At the histopathologic examination, calcification was found in 230 (45.7%) of the 503 discs. Of all affected discs, a severe degree of calcification was found in 30, a moderate degree in 45 and a slight degree in 155 discs. Calcified discs were identified in all the dogs and the number of calcified discs in each dog ranged from one (dog no. 19) to 24 (dog no. 17). The individual number and location of calcified discs together with the degree of calcification of each affected disc, identified both by radiography and histopathology, are presented in Additional file 1, Table 3. Comparative results by radiographic and histopathologic examination concerning 503 discs are presented in Table 2. Of all the discs found to be calcified by histopathology (n = 230), 138 (60.0%) were found to be calcified by radi- ography. All the discs found to be calcified by radiography (n = 138) were also found to be calcified by histopathol- ogy. Using histopathology as the gold standard, a sensitiv- Page 4 of 7 (page number not for citation purposes)