OBJECTIVE To evaluate interobserver agreement for features used in presumptive diagnosis of acute noncompressive nucleus pulposus extrusion (ANNPE) or ischemic myelopathy by MRI, compare findings on postcontrast T1-weighted (T1W) MRI sequences with fat saturation (FS) for the 2 conditions, and determine whether length and directional patterns of hyperintensity of the intramedullary spinal cord on T2-weighted (T2W) fast spin echo (FSE) MRI sequences differ between dogs with these diseases.
DESIGN Retrospective, observational study.
ANIMALS 20 dogs with clinical signs compatible with ANNPE (n = 14) or ischemic myelopathy (6).
PROCEDURES 3 observers evaluated MRI data (including T2W FSE, T2W single-shot FSE, and T1W FS sequences) for dogs with a presumptive diagnosis of ischemic myelopathy or ANNPE. Interobserver agreement for variables of interest including presumptive diagnosis was assessed by κ statistic calculations. Associations between diagnosis and variables of interest were assessed with Fisher exact or Cochran-Mantel-Haenszel tests.
RESULTS Perfect interobserver agreement (κ = 1 for all comparisons) was found for the presumptive diagnosis of ischemic myelopathy versus ANNPE. Meningeal enhancement on postcontrast T1W FS MRI images and nonlongitudinal directional pattern of intramedullary hyperintensity on T2W FSE images were significantly associated with a diagnosis of ANNPE. Greater length of intramedullary hyperintensity was significantly associated with a diagnosis of ischemic myelopathy.
CONCLUSIONS AND CLINICAL RELEVANCE Directional pattern and length of intramedullary hyperintensity on T2W FSE MRI images and enhancement patterns in postcontrast T1W FS sequences may provide important contributions to the criteria currently used in the presumptive diagnosis of ischemic myelopathy versus ANNPE.
Procedures—Nonsedated cats were positioned in dorsal and left lateral recumbency to obtain ultrasonographic measurements of the gallbladder via the subcostal and right intercostal acoustic windows, respectively. Gallbladder volume was calculated from linear measurements by use of an ellipsoid formula (volume [mL] = length [mm] × height [mm] × width [mm] × 0.52). Measurements were recorded after food was withheld for 12 hours (0 minutes) and at 5, 15, 30, 45, 60, and 120 minutes after cats were fed 50 g of a standard commercial diet (protein, 44.3%; fat, 30.3%; and carbohydrate, 15.6% [dry matter percentage]).
Results—Agreement between gallbladder linear measurements or GBV obtained from the subcostal and right intercostal windows was good. Feeding resulted in linear decreases in gallbladder linear measurements and GBV. Via the subcostal and intercostal windows, mean ± SD GBV was 2.47 ± 1.16 mL and 2.36 ± 0.96 mL, respectively, at 0 minutes and 0.88 ± 0.13 mL and 0.94 ± 0.25 mL, respectively, at 120 minutes. Gallbladder width most closely reflected postprandial modification of GBV.
Conclusions and Clinical Relevance—Results indicated that ultrasonographic assessment (via the subcostal or right intercostal acoustic window) of postprandial changes in GBV can be used to evaluate gallbladder contractility in cats. These data may help identify cats with abnormal gallbladder emptying.
Objective—To assess the variability in vertebral heart score (VHS) measurement induced by cardiac and respiratory cycles in dogs.
Design—Prospective observational study.
Animals—14 healthy Beagles.
Procedures—Dogs underwent fluoroscopic examination by 4 observers, and VHS was measured at end-tidal inspiration and end-tidal expiration during end systole and end diastole in left and right lateral recumbency. Mean VHS was compared within and among cardiac and respiratory phases and recumbency type, and correlation between VHS and heart rate was investigated. Interobserver variability was assessed.
Results—Mean VHS for each combination of respiratory and cardiac cycle was larger on images obtained in right lateral versus left lateral recumbency. The greatest differences were observed between VHS measured in the diastolic inspiratory phase (mean ± SD, 10.59 ± 0.49 vertebral units [VU] and 10.35 ± 0.50 VU for right and left lateral recumbency, respectively) and the systolic expiratory phase (10.11 ± 0.37 VU and 9.92 ± 0.50 VU for right and left lateral recumbency, respectively). The combination of respiratory and cardiac cycles induced a maximal difference in VHS of up to 0.97 VU and 1.11 VU in the inspiratory and expiratory phases, respectively. Heart rate was not correlated with the difference between VHS in systolic and diastolic phases.
Conclusions and Clinical Relevance—Clinicians should be aware of the potential influence of these factors when assessing VHS in dogs; in addition to allowing optimal pulmonary assessment, consistently taking radiographs at end-inspiratory tidal volume may help to limit VHS variability attributable to the respiratory cycle. Further research is needed to assess the effects of cardiac and respiratory phases on VHS in dogs with cardiac or respiratory disease.