title: Fat-suppressed spoiled gradient-recalled imaging of equine metacarpophalangeal articular cartilage.
abstract: The purpose was to evaluate the capacity of 1.5 T magnetic resonance (MR) imaging to assess articular cartilage in racehorses with naturally occurring metacarpophalangeal joint osteoarthritis. A sagittal, three-dimensional spoiled gradient-recalled echo (SPGR) with fat saturation (FS) sequence was acquired ex vivo on 20 joints. Following joint dissection, specific areas on the third metacarpal condyle were designated for subsequent sampling for histologic cartilage thickness measurement and modified Mankin scoring. Cartilage thickness was measured and cartilage signal intensity was also graded (0-3) on MR images at these selected metacarpal sites. Cartilage structure was graded (0-3) macroscopically and on MR images by two examiners in defined subregions of the proximal phalanx, third metacarpal, and proximal sesamoid bones. There was good precision (mean error 0.11 mm) and moderate correlation (r = 0.44; P < 0.0001) of cartilage thickness measurements between MR images (0.90 +/- 0.17mm) and histology (0.79 +/- 0.16 mm). There was moderate correlation between modified Mankin histologic score and signal intensity of cartilage (r = 0.36; P < 0.01) or MR cartilage structure assessment (r = 0.49, P > 0.001) on SPGR-FS. The sensitivity to detect full-thickness cartilage erosion on MR was only moderate (0.56), and these lesions were often underestimated, particularly when linear in nature. However, the specificity to detect such lesions on MR was high (0.92). While few limitations were identified, the use of a clinically applicable SPGR-FS sequence allows a reasonably accurate method to assess structural changes affecting the articular cartilage of the equine metacarpophalangeal joint.
authors.affiliation: Département de biomédecine yétérinaire, Faculte de médecine vétérinaire, Université de Montreal, 3200 rue Sicotte, P.O. Box 5000, Saint-Hyacinthe, QC, Canada.
authors.forename: Julien
authors.initials: J
authors.lastname: Olive
authors.forename: Marc-André
authors.initials: MA
authors.lastname: D'Anjou
authors.forename: Christiane
authors.initials: C
authors.lastname: Girard
authors.forename: Sheila
authors.initials: S
authors.lastname: Laverty
authors.forename: Christine
authors.initials: C
authors.lastname: Theoret
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000000981:diagnostic imaging* / Q000473:pathology; D017352:Echo-Planar Imaging / Q000592:standards / Q000662:veterinary*; D033023:Foot Joints / Q000000981:diagnostic imaging; D006734:Horse Diseases / Q000000981:diagnostic imaging* / Q000473:pathology; D006736:Horses; D016014:Linear Models; D050279:Metacarpal Bones / Q000000981:diagnostic imaging*; D010003:Osteoarthritis / Q000000981:diagnostic imaging / Q000473:pathology / Q000662:veterinary; D011859:Radiography; D012680:Sensitivity and Specificity