Robert H. Wrigley

Intra-arterial cisplatin with or without radiation in limb-sparing for canine osteosarcoma

Methods. Forty‐nine dogs with spontaneously occurring osteosarcoma underwent limb‐sparing surgery after preoperative therapy consisting of intra‐arterial cisplatin alone or intra‐arterial cisplatin in combination with doses of radiation from 20–40 Gy in 10 fractions. All resections were marginal, and the defect was repaired with a cortical allograft.

Radiotherapy prior to cortical allograft limb sparing in dogs with osteosarcoma: A dose response assay☆

Twenty-one dogs with spontaneously occurring appendicular osteosarcoma were given preoperative radiation therapy prior to a limb sparing procedure using a cortical allograft. Radiation doses were randomly assigned, ranged from 36-52 Gy in 4 Gy intervals, and were given in 10 equally-sized fractions on a M, W, F schedule. Seventeen of the 21 dogs underwent the limb sparing procedure approximately 3 weeks after completion of radiation therapy. Local tumor recurrence was documented in 4 of 17 dogs at mean and median times of 5.5 and 5.8 months, respectively, after initiation of radiation therapy. Three of 4 recurrences were in anatomic regions with sparse adjacent soft tissue which precluded wide excision. Complications were significant. Fixation device failure occurred in 9 of 17 dogs and was associated with host bone necrosis, muscle thinning and fibrosis of vessels and nerves in irradiated normal tissue. Incidence of host bone necrosis was directly related to radiation dose (Kendalls statistic, p = 0.005). Metastasis occurred in all 21 dogs. Mean and median times to metastasis in these dogs were 5.1 and 4.0 months, respectively, after initiation of radiation therapy. Local tumor control rates and survival times were higher in dogs developing allograft infection suggesting that infection acted as an immunostimulant. All local failures occurred in dogs that did not develop allograft infection and median survival times for uninfected versus infected dogs were 5 and 11 months, respectively (logrank test, p = 0.029). Increased tumor radiopacity following radiation therapy was significantly related to survival. Median survival in dogs whose tumors were characterized by decreased, unchanged or increased opacity after radiation therapy were 3.5 and 14 months, respectively (logrank test, p = 0.014). Based on the results of our study, radiation therapy can not be recommended as part of limb sparing treatments for patients with osteosarcoma at doses and dose per fraction values similar to those used herein.

ULTRASONOGRAPHIC IDENTIFICATION OF VASCULAR INVASION BY ADRENAL TUMORS IN DOGS

Adrenalectomy is the treatment of choice for adrenal tumors that are producing adverse clinical signs. Surgical planning prior to adrenalectomy is aided by identifying tumors with invasion into adjacent vessels or the presence of a tumor thrombus extending into the caudal vena cava. In this paper, we evaluated the sensitivity and specificity of ultrasound in determining if vascular invasion or tumor thrombus is present. Thirty-four dogs with 36 adrenal tumors were reviewed retrospectively. Overall, 36% of tumors had vascular invasion. Abdominal ultrasound was 100% sensitive and 96% specific in identifying the presence of a tumor thrombus in the caudal vena cava. The sensitivity and specificity was 76% and 96%, respectively, when all forms of vascular invasion were evaluated and included patients with vascular wall invasion without concurrent thrombus. Abdominal ultrasound is a good screening tool for identifying vascular invasion or tumor thrombus associated with adrenal tumors in dogs.

Ultrasonography of the acute abdomen.

For many years, ultrasonography has been considered to be one of the most valuable imaging techniques for evaluation of the abdominal cavity and its organs. In most cases, abdominal ultrasonography helps obtain information that leads to a definitive diagnosis. Ultrasonography is also valuable to narrow the list of differential diagnoses obtained with other diagnostic techniques. This article discusses the role of ultrasound for the diagnosis of the most common diseases that can produce clinical signs of acute abdominal pain. Abdominal organs that can be evaluated using ultrasound include the liver, biliary system, pancreas, stomach, small intestine, kidney, urinary bladder, uterus, and prostate. Pathologies of the abdominal cavity and retroperitoneal space can be also diagnosed with ultrasonography. Interventional ultrasound techniques are useful to either assist in getting the definitive diagnosis or to treat certain pathologic conditions.

Radiographic Interpretation of Normal Skeletal Variations and Pseudolesions in the Equine Foot

Effective radiographic interpretation requires a veterinarian who is knowledgeable of equine limb anatomy and the various principles that affect the resulting image. The normal and its variations must be recognized and understood before the abnormal can be confidently identified as pathologic. Proper patient positioning and sound radiographic technique are mandatory if reliable diagnostic radiographs are to be produced. This review emphasizes equine foot radiographic variations of normal and pseudolesions that occur with commonly used radiographic views performed in equine practice.

Efficacy of Imagent BP at 1.5ml/kg in a rabbit liver tumor model.

We have shown using a Vx2 rabbit model that 3 and 5ml/kg of perflubron emulsion were highly effective in imaging liver tumors. The results from preliminary clinical trials suggested that should the infusion rate be increased, a 1.5ml/kg may be efficacious. This study determined whether 1.5ml/kg given as a bolus IV would be efficacious to image liver tumors using a Vx2 rabbit model. Vx2 tumors were implanted in 5 NZW rabbits, CT of the liver was performed during held expiration at 80kV and 800mAS, before and shortly after 1.5ml/kg Imagent BP (ImBP), again at 30 minutes and 3 days. Regions of interest (ROIs) were drawn over the CT image of the spleen, liver, inferior vena cava, and tumor, CT# obtained and average enhancement of each tissue calculated at each time point. 4 animals had tumors .5cm or greater. Precontrast, tumors were faintly seen on CT. Blood was brighter than liver shortly after infusion and isointense with liver at 30 minutes. Tumors did not enhance following contrast. Except for the liver and spleen, all tissues returned to baseline on the 3rd day. Therefore a clinical trial to determine the efficacy of 1.5ml/kg ImBP to image the liver is warranted.

Sonographic Determination of Pregnancy in Amazon Tree Boas, Corallus hortulanus

ABSTRACT Three Amazon tree boas, Corallus hortulanus, were evaluated sonographically for pregnancy, four to five months post-fertilization. Sonography revealed hyperechoic, segmented, linear structures (the fetal spine) and presence o f cardiac activities as flickering motion. Fetus presentation varied, some curled concentrically and others folded back on themselves. Differing amounts of amniotic and/or allantoic anechoic fluid and residual echogenic yolk were present. Sonography of unfertilized ova revealed a homogeneous echogenic mass surrounded by a linear hyperechogenic membrane.