Abstract:The purpose of this study was to report the scintigraphic and sonographic appearance of the thyroid gland in clinically normal horses so these modalities could be used to assess the thyroid gland in this species. Horses were divided into two age groups. Group A consisted of 8 horses between 3 and 10 years of age and Group B of 7 horses between 11 and 20 years of age. Total T 4 concentrations were within the laboratory reference interval. Thyroid to salivary (T/S) ratio, percent dose uptake of pertechnetate and thyroid lobe volume were calculated. Echogenicity of thyroid lobes and presence of nodules were documented. The two groups were compared using appropriate parametric and nonparametic tests. Total T 4 concentrations were significantly lower in the older group. Sixty minute mean ± standard deviation (SD) T/S ratios for older versus younger horses were 5.8 ± 3.0 and 5.3 ± 2.2, respectively. Sixty minute median and interquartile ranges for percent dose uptake of pertechnetate for older versus younger horses were 3.64% (1.5 to 3.98%) and 2.55% (2.33 to 2.90%), respectively. Mean ± SD thyroid lobe volumes for older versus younger horses were 18.93 ± 5.16 cm 3 and 13.55 ± 3.56 cm 3 , respectively. Most thyroid lobes were hyper or isoechoic to the sternocephalicus muscle. Prevalence of thyroid nodules did not differ between groups. Older horses had trends for greater T/S ratios, percent dose uptakes and thyroid lobe volumes but had lower total T 4 concentrations. Further studies using scintigraphy and ultrasound in horses with thyroid disease are planned.

Bisection nephrotomy, as described in this study, does not decrease renal function; perioperative administration of renoprotective agents is not necessary in normal dogs.

An approach combining ventral midline celiotomy with transdiaphragmatic thoracotomy was evaluated in eight healthy cats for ligation of the thoracic duct system. Evans Blue solution was injected into the right colic lymph node to outline the intestinal lymphatic trunk and the thoracic duct system. Three cats (group 1) had mesenteric lymphangiograms and three (group 2) had only lymph node dye injection before thoracic duct ligation. The thoracic duct system was ligated with hemostatic clips just cranial to the aortic hiatus of the diaphragm, through a left transdiaphragmatic thoracotomy. Two cats (group 3) had prethoracotomy mesenteric lymphangiograms and thoracic duct isolation without ligation. Mesenteric lymphangiography was performed immediately after the surgery. In all of the cats, an absence of contrast medium in the thoracic duct system cranial to the surgical site was interpreted as complete obstruction. Four weeks after ligation, there was complete obstruction of the thoracic duct system with alternate lymphaticovenous communications in four of the six cats with ligated thoracic duct systems. Partial obstruction of the thoracic duct system with alternate lymphaticovenous communications was present in the other two cats. Both cats without thoracic duct ligation had patent thoracic duct systems. At necropsy of the six cats with ligated thoracic ducts, there was mild focal lymphadenitis of injected lymph nodes in three cats. The wall of the aorta adjacent to the hemostatic clips was normal in all six cats. The surgical technique was simple and provided excellent exposure. Vital staining with Evans Blue helped visualize the thoracic duct system, but mesenteric lymphangiography did not. Postligation lymphangiography was not of value in identifying incomplete ligation.

Three-view thoracic radiography is often used to evaluate patients for pulmonary metastatic disease. Although use of three views has been reported to be more sensitive than two views for focal lung disease, it also requires increased time, effort, and radiographic exposure of patients and personnel. This study was performed to evaluate the conspicuity of lesions on two-view vs. three-view radiographic procedures to determine the proportion of diagnoses that would change. One hundred three-view radiographic studies of the canine thorax were randomized, and four protocols were reviewed for each study: right lateral and ventrodorsal views, left lateral and ventrodorsal views, both lateral views, and all three views. Radiographs were interpreted as either positive or negative for structured interstitial pulmonary disease, and the certainty of the reading was recorded using a visual analog scale. There was 85-88% agreement between each two-view group and the three-view group, with the kapp statistic ranging from 0.698 to 0.758. There were no differences in certainty of diagnosis among the groups, though within each group there was more certainty for positive diagnoses than negative diagnoses. These findings indicate that three-view studies should be continued when evaluating for possible structured interstitial pulmonary disease, including metastatic disease, as eliminating one view from a three-view study would change the diagnosis in 12-15% of patients.

The nephrographic phase of the excretory urogram may be used to qualitatively assess some functional aspects of renal disease. Functional abnormalities of the kidney which alter the normal pattern of nephrographic opacification may be associated with renal perfusion abnormalities, glomerular dysfunction, intra or extrarenal obstruction, renal tubular necrosis and adverse reactions (renal or systemic) to iodinated contrast media. The time of maximum nephrographic opacification following intravenous injection of contrast medium and variations in nephrographic opacity before and after maximum opacification may help differentiate these disease processes. Standard radiographic and urographic techniques must be used to prevent changes caused by variations in contrast medium dosage and filming sequence from being misinterpreted as functional renal abnormalities.