Radiation therapy planning using MRI-CT fusion in dogs and cats with brain tumors.

INTRODUCTION: Volume definition is a delicate step within the radiation treatment planning process and the precision of defining the volumes to irradiate is important for the success of the radiation treatment. Traditionally, radiation plans are created using computed tomography (CT) studies. Due to its different mechanism of action, magnetic resonance imaging (MRI) is more sensitive for detection of brain lesions. Therefore, using fused images of both imaging modalities should result in a more precise definition of the volumes to irradiate. The feasibility to fuse CT and MRI studies performed at different institutions was tested to subsequently analyse the influence of the fused images on target volume definition. MATERIALS AND METHODS: Fourteen dogs and four cats with brain lesions having MR- and CT-imaging were included. Contrast-enhanced radiotherapy planning CT scans were fused to T1-weighted post-contrast and T2-weighted MRI scans. The gross tumor volume (GTV), the clinical tumor volume (CTV) and the planning target volume (PTV) were delineated on CT- and MRI studies. CT and MRI volumes were compared with regard to volumetric and spatial differences. RESULTS: The mean GTV was larger on MRI than on CT (2.15 vs.1.54 cm3). Also the mean CTV was larger on MRI than on CT (5.34 vs. 4.38 cm3). Consequently, the mean PTV was larger on MRI than on CT (14.20 vs. 10.82 cm3) as well. None of the differences in defined volumes were significant. Fusion images were accepted showing mean errors of 1.32 mm (mean error) and 1.73 mm (maximal error). CONCLUSION: CT-MRI fusion was feasible especially when defined, reliable, and consistent anatomic landmarks were used as registration points. Volumetric differences between CT and MRI were insignificant. In general, GTV and CTV were easier identified on MRI.

Chemotherapy and radiation therapy in 4 dogs with muscle-invasive transitional cell carcinoma of the urinary tract.

Four dogs with T(2)N(0)M(0) transitional cell carcinoma of the lower urinary tract underwent multimodal treatment consisting of neoadjuvant chemotherapy, external-beam radiotherapy, and adjuvant chemotherapy. No significant toxicity was documented. All dogs showed clinical improvement and reduction of tumor volume based on computed tomography (CT).

RésuméChimiothérapie et radiothérapie comme traitement pour carcinomes à cellules transitionnelles urothéliaux avec infiltration du muscle dans 4 chiens. Quatre chiens avec des carcinomes à cellules transitionnelles du bas tractus urinaire (TNM) ont été traités avec une approche multimodale consistent en chimiothérapie néodjuvante, radiothérapie externe et chimiothérapie adjuvante. Nous n'avons pas observé une toxicité signifiante. Tous les chiens ont répondu à ce traitement multimodale, défini comme amélioration des symptômes cliniques et réduction des dimensions de la tumeur, indiqué au scanner.(Traduit par Julia Buchholz).

Analysis of exhaled breath condensate in a mixed population of psittacine birds.

Collection of exhaled breath condensate (EBC) and the measurement of inflammatory markers contained therein (eg, hydrogen peroxide [H2O2], leukotriene B4 [LTB4], and pH) have been reported to be noninvasive tools for the investigation of respiratory disease in various species. In this study, the EBC of clinically healthy psittacine birds (n = 15) and psittacine birds with respiratory tract disease (n = 19) was examined, and inflammatory markers contained in the EBC were analyzed and compared. Awake birds were placed in an acrylic container from which the outflow passed through a condensation system that collected the EBC. All samples were analyzed for pH, H2O2, and LTB4. The mean values for each of these components, as well as the mean volume of the total EBC, measured from the apparently healthy birds did not differ significantly from those measured in birds with signs of respiratory tract disease. However, LTB4 in the EBC of diseased birds was higher than that of the apparently healthy birds and showed a trend toward significance. The study demonstrated the establishment of a standardized method for collecting and analyzing EBC in psittacine birds and a measurement protocol for pH, H2O2, and LTB4.

Dynamic computed tomography to measure tissue perfusion in spontaneous canine tumors.

Dynamic computed tomography (CT) is widely used in humans to determine tumor perfusion via time-attenuation curves. Five types of time-attenuation curves have been identified and shown to have prognostic relevance in humans. The goal of our study was to assess the feasibility of this technology in spontaneous canine tumors and to determine time-attenuation curves and perfusion patterns in different tumor types. Thirty-one dogs with tumors accessible for biopsy were evaluated (15 carcinomas, 16 sarcomas). Dynamic CT was performed at the level of the largest tumor cross-section. Time-attenuation curves were calculated and ratios from the tumor to a contralateral artery were derived for wash-in, peak attenuation, time to peak attenuation, wash-out, and perfusion. Median perfusion was significantly higher and median time to peak ratio was significantly shorter in carcinomas and bone sarcomas compared with soft tissue sarcomas (P = 0.03 and 0.01). There was a trend of lower median upslope and wash-out ratio in soft tissue sarcomas in comparison with carcinomas (P = 0.06 and 0.09). Although peak ratio was lowest in soft tissue sarcomas, differences were not significant (P = 0.3). The most common type of time-attenuation curve for all tumors had a slow to moderately rapid wash-in with a low to moderate attenuation peak followed by a plateau phase. In conclusion, dynamic CT is feasible and time-activity curve-derived measurements differed between spontaneous canine tumors. More data has to be collected in a larger number of patients and correlated with response to treatment and outcome.

Endocarditis due to Lactobacillus jensenii in a Salvin's Amazon parrot (Amazona autumnalis salvini).

A 30-year-old Salvin's Amazon parrot (Amazona autumnalis salvini) with a history of a lifelong poor diet and inappropriate housing was presented in lateral recumbency to a veterinary teaching hospital for further evaluation. Radiological and ultrasonographic examination revealed a mild proventricular dilatation, mild hepatomegaly, signs of enteritis and airsacculitis. The main laboratory findings included a mild macrocytic hyperchromic anaemia, hypoglobulinaemia, decreased bile acids and increased alkaline phosphatase. In this bird a liver pathology was suspected because of the clinical, laboratory and ultrasonographic findings. The bird was treated with supportive care and metabolic aids. After initial improvement of the clinical signs, the bird's condition deteriorated and it died. Pathological findings revealed an endocarditis and myocarditis due to Lactobacillus jensenii and a bacteraemia. Endocarditis due to Lactobacillus sp. is a rare phenomenon in humans not yet described in animals. It is associated with severe underlying illnesses leading to translocation of otherwise non-pathogenic bacteria in the bloodstream. A similar pattern might be assumed in animals with compromised immunity.

Quantification of the effect of various patient and image factors on ultrasonographic detection of select canine abdominal organs.

We assessed factors that affected ultrasonographic visualization of the pylorus, duodenal papilla, pancreas, adrenal glands, and jejunal and medial iliac lymph nodes in the dog. An abdominal ultrasonographic examination was performed on 100 canine patients, equally divided between two facilities. The pylorus was visible in 64% of the dogs, the major duodenal papilla in 42%, the left pancreatic lobe in 56%, the body of the pancreas in 60%, the right pancreatic lobe in 87%, the left adrenal gland in 91%, the right adrenal gland in 86%, the medial iliac lymph nodes in 54%, and the jejunal lymph nodes in 51%. The parameters that negatively influenced the visibility of these organs were the presence of air or food in the gastrointestinal tract (pancreas, duodenal papilla), age (lymph nodes), and body weight (pancreas, duodenal papilla). The parameters that positively influenced their visibility were the presence of air or food in the gastrointestinal tract (lymph nodes), body weight (lymph nodes), body condition score (right adrenal gland), and inherent image quality (left pancreatic lobe). There was a significant difference between the two institutes for the visualization of the pylorus, pancreas, and lymph nodes, which was probably related to different body positions used for scanning in each institution.

Palliative radiotherapy with electrons of appendicular osteosarcoma in 54 dogs.

Radiotherapy is effective for the palliation of pain associated with primary and metastatic bony neoplasia in dogs and humans, but no standard treatment protocol has been established. The goal of this study was to evaluate a 3 x 8 Gy and a 4 x 6 Gy protocol using electrons with a betatron or linear accelerator for the treatment of appendicular osteosarcoma in 54 dogs. Thirty-three dogs received chemotherapy consisting of carboplatin IV concurrently with radiotherapy. Eighty-three % (n = 45) of the dogs experienced pain relief during or following treatment. The median duration of pain relief from treatment start was 53 days. In conclusion, both protocols are effective for palliation of clinical signs of canine appendicular osteosarcoma. The outcome reported here is similar to the results of other studies using Co photons. The use of chemotherapy did not improve the response to radiotherapy.