Sensitivity of low-field T2 images for detecting the presence and severity of histopathologic meniscal lesions in dogs.

The sensitivity of low-field magnetic resonance (MR) T2 images for predicting the presence of meniscal lesions was determined in 12 dogs with naturally-occurring cranial cruciate ligament rupture and three control dogs, using histopathology as the reference standard. Previously published grading systems were used to grade the severity of meniscal lesions on MR images, gross inspection and histopathology. Focal areas of increased signal intensity were detected in 11/12 symptomatic dogs and 3/3 control dogs. Lesions mimicking meniscal tears (pseudotears) were identified at junctions between meniscal margins and adjacent connective tissue in control dogs and dogs with naturally occurring disease. Histopathologic lesions were present in all menisci of both symptomatic and control dogs, including the menisci from two affected dogs that appeared grossly normal but were removed and submitted based on MR imaging findings. Histopathologic lesions identified included hyaline cartilage metaplasia and changes in the amount of ground substance and cellularity. The sensitivity of MR imaging for detecting the presence of meniscal histopathologic lesions was 90% in symptomatic dogs and 91% in control dogs. However, agreement between severity scores for the different tests was poor. Low-field MR imaging is a sensitive test for predicting the presence but not severity of meniscal histopathologic lesions in dogs with naturally-occurring cranial cruciate ligament rupture. Findings also supported previous studies indicating that histopathologic lesions can be present in dogs with grossly normal menisci. An improved grading system for comparing MR images and histopathologic severity of meniscal lesions in dogs is needed.

Multiple magnet ingestion as a cause of septic peritonitis in a dog.

A 1 yr old male castrated Yorkshire terrier was referred after ingesting magnets. Dehydration, fever, tachycardia, and abdominal pain were noted on physical examination. Abdominal radiographs revealed two radiopaque foreign objects in close proximity to each other with decreased abdominal detail. Surgical exploration identified magnets adhered together in the omentum with perforations present in the transverse colon and stomach. The perforations were closed and a Jackson-Pratt continuous suction drain was placed. Septic peritonitis secondary to intestinal perforation from magnet ingestion was successfully treated with a combination of surgery and a closed suction drain.