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- Author or Editor: Kari L. Anderson x
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Objective—To determine the relationship between surface emission rate of gamma radiation and urine concentration of I131 (urine radioactivity) during the period 7 to 21 days after oral or SC administration of I131 to hyperthyroid cats.
Animals—47 hyperthyroid cats administered I131 PO and 24 hyperthyroid cats administered I131 SC.
Procedure—A dose of I131 (1.78 to 2.04 X 102 MBq [4.8 to 5.5 mCi]) was administered orally. Surface emission at the skin adjacent to the thyroid gland on days 7, 10, 14, 18, and 21 and number of counts/30 s in a urine sample (1 mL, obtained via cystocentesis) on days 7, 14, and 21 after oral administration were measured. Effective half-life (T1/2E) was derived for each point. Surface emission thresholds for maximum urine radioactivity values were established. A dose of I131 (1.48 X 102 MBq [4.0 mCi]) was administered SC. Urine radioactivity and surface emission rates for SC administration were compared with values for oral administration.
Results—The T1/2E for surface emissions and urine radioactivity progressively increased toward values for physical T1/2 over time. The T1/2E for surface emissions was 2.19 to 4.70 days, and T1/2E for urine radioactivity was 2.16 to 3.67 days. Surface emission rates had a clinically useful threshold relationship to maximum urine concentrations of I131.
Conclusions and Clinical Relevance—Surface emission rates for cats administered I131 appeared useful in determining upper limits (threshold) of urine radioactivity and are a valid method to assess the time at which cats can be discharged after I131 administration. (Am J Vet Res 2003;64:1242–1247)
Objective—To evaluate scintigraphy, radiography, and histomorphometric analysis for assessing incorporation of intercalary bone grafts and to compare incorporation of cortical autografts and allografts by the recipient.
Animals—12 skeletally mature sheep.
Procedures—A 5-cm tibial defect was filled with a cortical allograft (n = 6) or autograft (6) and stabilized with an interlocking nail. Radiography, scintigraphy, and fluorochrome bone labeling were performed every 3 months for 24 months. Radiographic evaluation included grading of the host and graft union and assessment of implants and grafts. Technetium-99m-hydroxymethylene diphosphonate radionuclide uptake was measured. Sheep were euthanatized 24 months after surgery, and bone formation was evaluated via histomorphometric analysis of fluorochrome labeling.
Results—Complete union was detected on radiographs by 21 months in all sheep but developed earlier in sheep that received an autograft versus in those that received an allograft. Radionuclide uptake peaked at 3 months and returned to presurgical values at 12 months. Histomorphometric analysis revealed fluorochrome labeling corresponding to each time point, with most bone formation at 9 through 15 months. Scintigraphy findings did not correlate well with fluorochrome labeling of newly formed bone.
Conclusions and Clinical Relevance—Although bone production around cortical bone grafts was detected by use of scintigraphy, this method did not provide accurate assessment of graft incorporation in sheep. Furthermore, bone produced by activated periosteum could not be distinguished scintgraphically from bone that replaced the graft. Intercalary autografts healed more rapidly and had greater incorporation into the host bone, compared with findings for allografts.
Objective—To determine whether objectively applied ultrasonographic interpretive criteria are statistically useful in differentiating among 7 defined categories of diffuse liver disease in dogs and cats.
Sample Population—Ultrasonographic images of 229 dogs and 104 cats.
Procedures—Liver parenchymal or related sonographic criteria established by the authors were retrospectively and independently applied by 3 radiologists who were not aware of patient status or patient laboratory data. Seven histologic or cytologic categories of diffuse (infiltrative but not nodular) liver diseases were jointly established by the authors and included normal liver; inflammation; round-cell neoplasia; non–round-cell infiltrative, prenodular (early) metastatic neoplasia; lipidosis; vacuolar hepatopathy; and other. Liver parenchymal sonographic criteria included parenchymal sound attenuation with increasing depth, comparative organ echogenicity (liver, spleen, and kidneys), diffuse or patchy hyperechoic or hypoechoic echotexture, uniform or coarse echotexture, portal venous clarity, and liver lobe geometry. Related extrahepatic criteria included gallbladder wall thickness, bile duct diameter, amount and character of gallbladder precipitate, nondependent shadowing in the gallbladder, hepatic vein diameter versus caudal vena cava diameter, peritoneal fluid, spleen echotexture (normal vs abnormal [characterized]), and kidney echotexture. Ultrasonographic criteria were statistically compared to the 7 categories of diffuse liver disease in search of clinically exploitable relationships.
Results—Statistical evaluation of the applied ultrasonographic criteria did not yield clinically acceptable accuracy for discrimination among the 7 categories of diffuse liver diseases (including normal liver) in either species.
Conclusions and Clinical Relevance—Criterion-based ultrasonographic appearance was insufficient to discriminate among canine and feline diffuse infiltrative liver diseases.
OBJECTIVE To determine clinical relevance for quantitative and qualitative features of canine hepatic masses evaluated by use of triphasic CT and B-mode, color flow, power, and pulsed-wave Doppler ultrasonography and to compare diagnostic accuracy of these modalities for predicting mass type on the basis of histopathologic classification.
ANIMALS 44 client-owned dogs.
PROCEDURES Dogs with histopathologic confirmation (needle core, punch, or excisional biopsy) of a hepatic mass were enrolled. Triphasic CT and B-mode, color flow, power, and pulsed-wave Doppler ultrasonography of each hepatic mass were performed. Seventy quantitative and qualitative variables of each hepatic mass were recorded by 5 separate observers and statistically evaluated with discriminant and stepwise analyses. Significant variables were entered in equation-based predictions for the histopathologic diagnosis.
RESULTS An equation that included the lowest delayed-phase absolute enhancement of the mass and the highest venous-phase mass conspicuity was used to correctly classify 43 of 46 (93.5%) hepatic masses as benign or malignant. An equation that included only the lowest delayed-phase absolute enhancement of the mass could be used to correctly classify 42 of 46 (91.3%) masses (with expectation of malignancy if this value was < 37 Hounsfield units). For ultrasonography, categorization of the masses with cavitations as malignant achieved a diagnostic accuracy of 80.4%.
CONCLUSIONS AND CLINICAL RELEVANCE Triphasic CT had a higher accuracy than ultrasonography for use in predicting hepatic lesion classification. The lowest delayed-phase absolute enhancement of the mass was a simple calculation that required 2 measurements and aided in the differentiation of benign versus malignant hepatic masses.