Ultrasonographic and CT accuracy in localising surgical- or necropsy- confirmed solitary hepatic masses in dogs

OBJECTIVES

To estimate the sensitivity and specificity of ultrasound and CT for localising solitary hepatic masses to particular liver divisions.

MATERIALS AND METHODS

Dogs diagnosed with a solitary liver mass by ultrasound and/or CT, with surgical or necropsy confirmation within 1 month of imaging. Ultrasound reports were reviewed for mass location. CT scans were reviewed by two radiologists and mass location was determined by consensus agreement. Sensitivity and specificity were calculated for ultrasound and CT for each liver division.

RESULTS

Fourteen of 71 dogs had CT only, 27 of 71 had ultrasound only and 30 of 71 had both. Location was correctly predicted in 42 of 57 dogs (74%) by ultrasound and in 37 of 44 dogs (84%) by CT. Both CT and ultrasound had high specificity for localising masses in all divisions. Sensitivity varied among divisions and was highest for left division masses.

CLINICAL SIGNIFICANCE

The results suggest that either imaging modality is appropriate for presurgical planning. Prospective studies are recommended to help identify additional factors that may aid in determination of hepatic mass location.

The dural tail sign in the diagnosis of meningiomas

In humans the dural tail is a sign seen on contrast enhanced T1 weighted magnetic resonance images. This finding is considered specific for meningioma. The purpose of this study was to determine how often the dural tail occurs in cats and dogs and whether it is a specific sign for meningiomas in these species. MR examinations for eighteen dogs and four cats with proven diagnoses were reviewed. Diagnoses included ten meningiomas (seven dogs and three cats), three gliomas, two pituitary tumors, single examples of two other tumor types and five patients with mass lesions due to inflammatory disease. Contrast enhanced T1 weighted images were evaluated independently by three of the authors for the presence of a dural tail, without knowledge of the diagnoses. The results were compared to the diagnosis for each patient and the performance of individual reviewers compared. When their results were averaged, the reviewers reported the presence of a dural tail in 6 of 10 (60%) meningiomas, although detection varied between observers from 40% to 80%. Each reviewer had one false positive result, two reported a dural tail with a chromophobe adenocarcinoma and one with a toxoplasma meningoencephalitis. When a dural tail is seen an associated mass is most likely a meningioma. It is uncertain whether the dural tail represents neoplastic infiltration beyond the margins of the meningioma. This should be considered when planning treatment.

True diaphragmatic hernia in a cat

A report of a cat with a true diaphragmatic hernia in which only falciform fat had herniated is presented. The lesion was misinterpreted as a pulmonary mass. Additional radiographic studies which may have been of diagnostic benefit are briefly discussed.