ACVR and ECVDI consensus statement for teleradiology.

Increased demand for the interpretation of diagnostic images by board-certified radiologists and profound advancements in technology have led to extremely rapid growth in the field of veterinary teleradiology over the past decade. The aim of this consensus statement is to provide a guideline for best practices for quality and safety in veterinary teleradiology. The statement addresses appropriate image acquisition and transmission, the creation of teleradiology submissions, quality control in teleradiology, and appropriate documentation of imaging reports, as deficiencies in any of these areas may directly affect the standard of patient care. The consensus statement may be used as a guide for radiologists, primary care veterinarians, technicians, and students for the use of teleradiology in practice.

Dose-response relationship of ultrasound contrast agent in an in vivo murine melanoma model.

Many factors affect the sensitivity and reliability of tumor vasculature assessment at the small doses of contrast agent necessary for imaging mice. In this study we investigate the dose-response relationship of ultrasound contrast agent for a minimal exposure power Doppler technique (minexPD) in a murine melanoma model. K1735 murine melanomas grown in 25 C3H/HeN mice were imaged by power Doppler ultrasound using different doses of contrast agents, Optison(R) and Definity(R). Six mice were treated with an antivascular agent, combretastatin A4-phosphate (CA4P), and imaged before and after treatment. The color-weighted fractional area (CWFA) of the peak-enhanced image was measured to assess tumor perfusion on a relative scale of 0 to 100. CWFA increased logarithmically with dose (R(2)=0.97). Treatment with CA4P resulted in pronounced reduction in tumor perfusion 2 h after contrast injection, but perfusion recovered in the tumor periphery after 2 days. CWFA was significantly different between pre- and post-treatment for all doses at 2 h and 2 days (p < 0.05, respectively). There was no significant difference detectable between the two contrast agents, Optison(R) and Definity(R) (p = 0.46). In vivo tumor enhancement in mice increases as logarithmic function with dose. Although the extent of enhancement is dose dependent, the difference between pre- and post-therapy enhancement is relatively unchanged and uniform at varying doses. The two contrast agents tested in this study performed equally well. These results suggest that quantitative contrast-enhanced power Doppler imaging is an effective method for monitoring therapy response of tumors in mice.

The antivascular action of physiotherapy ultrasound on murine tumors.

This study was aimed at determining if physiotherapy ultrasound (US) affected the fragile and leaky angiogenic blood vessels in a tumor. In 22 C3HV/HeN mice, a subcutaneous melanoma (K1735(22)) was insonated (1, 2 or 3 min) with continuous 1-MHz low-intensity (spatial-average temporal-average = 2.28 W cm(-2)), physiotherapy US. Contrast-enhanced (0.1 mL Optison) power Doppler US observations were made and histogram analyses of the images were performed. Before insonation, all but 7% of the tumor was perfused. The avascular area in tumors receiving 3-min treatment increased to 82% (p < 0.001). A linear regression analysis showed that each min of insonation led to a 25% reduction in tumor vascularity; the antivascular activity persisted for 24 h. Histology demonstrated disruption of vascular walls and tumor cell death in areas of vascular congestion and thrombosis. Physiotherapy US particularly targeted the vascular structures, and the effects on tumor cells appeared to be secondary to the resultant ischemia.

Oxygen distribution in murine tumors: characterization using oxygen-dependent quenching of phosphorescence.

In the present work, a novel method for detecting hypoxia in tumors, phosphorescence quenching, was used to evaluate tissue and tumor oxygenation. This technique is based on the concept that phosphorescence lifetime and intensity are inversely proportional to the oxygen concentration in the tissue sample. We used the phosphor Oxyphor G2 to evaluate the oxygen profiles in three murine tumor models: K1735 malignant melanoma, RENCA renal cell carcinoma, and Lewis lung carcinoma. Oxygen measurements were obtained both as histograms of oxygen distribution within the sample and as an average oxygen pressure within the tissue sampled; the latter allowing real-time oxygen monitoring. Each of the tumor types examined had a characteristic and consistent oxygen profile. K1735 tumors were all well oxygenated, with a peak oxygen pressure of 37.8 +/- 5.1 Torr; RENCA tumors had intermediate oxygen pressures, with a peak oxygen pressure of 24.8 +/- 17.9 Torr; and LLC tumors were all severely hypoxic, with a peak oxygen pressure of 1.8 +/- 1.1 Torr. These results correlated well with measurements of tumor cell oxygenation measured by nitroimidazole (EF5) binding and were consistent with assessments of tumor blood flow by contrast enhanced ultrasound and tumor histology. The results show that phosphorescence quenching is a reliable, reproducible, and noninvasive method capable of providing real-time determination of oxygen concentrations within tumors.

Risk factors for recurrence of clinical signs associated with thoracolumbar intervertebral disk herniation in dogs: 229 cases (1994-2000).

OBJECTIVE: To assess risk factors for recurrence of clinical signs associated with thoracolumbar intervertebral disk disease (IVDD) in dogs that had decompressive laminectomy without attempted prophylactic treatment of other disk spaces. DESIGN: Retrospective study. ANIMALS: 229 dogs. PROCEDURE: Medical records of dogs that had decompressive laminectomy without prophylactic fenestration for a first episode of IVDD and were available for follow-up were reviewed. Information on 7 clinical and 8 radiographic potential risk factors were recorded. RESULTS: Clinical signs associated with recurrence of IVDD developed in 44 (19.2%) dogs. Ninety-six percent of recurrences developed within 3 years after surgery. Recurrence developed in 25% of Dachshunds and 15% of dogs of other breeds combined. Number of opacified disks was a significant risk factor for recurrence. Risk increased with number of opacified disks in an almost linear manner; each opacified disk increased risk by 1.4 times. Dogs with 5 or 6 opacified disks at the time of first surgery had a recurrence rate of 50%. CONCLUSIONS AND CLINICAL RELEVANCE: When all likely episodes of recurrence are considered and a long follow-up period is achieved, true rate of recurrence of IVDD appears to be higher than in many previous reports. Dogs with multiple opacified disks at the time of first surgery should be considered a high-risk subpopulation.

Medical and behavioral surveillance of dogs deployed to the World Trade Center and the Pentagon from October 2001 to June 2002.

OBJECTIVE: To evaluate early medical and behavioral effects of deployment to the World Trade Center, Fresh Kills Landfill, or the Pentagon on responding search-and-rescue (SAR) dogs. DESIGN: Prospective double cohort study. ANIMALS: The first cohort included SAR dogs responding to the September 11, 2001, terrorist attacks (deployed), and the second cohort included SAR dogs trained in a similar manner but not deployed (controls). Enrollment occurred from October 2001 to June 2002. PROCEDURE: Dogs were examined by their local veterinarians; thoracic radiographs and blood samples were shipped to the University of Pennsylvania for analysis. Handlers completed medical and training histories and a canine behavioral survey. RESULTS: Deployed dogs were older and had more search experience than control dogs. Serum concentrations of globulin and bilirubin and activity of alkaline phosphatase were significantly higher in deployed dogs, independent of age and training. Despite significant differences in several blood parameters, values for both groups were within reference ranges. No pulmonary abnormalities were detected on radiographs, and no significant differences in behavior or medical history were detected between groups. CONCLUSIONS AND CLINICAL RELEVANCE: Within the first year following the September 11 attacks, there was no evidence that responding dogs developed adverse effects related to their work. Mild but significantly higher serum concentrations of globulin and bilirubin and activity of alkaline phosphatase in deployed dogs suggested higher antigen or toxin exposure. These dogs will be monitored for delayed effects for at least 3 years.

Otolithiasis in three dogs.

Mineral opacities within the tympanic bullae, termed otoliths, were detected in three dogs by means of radiography and computed tomography. Radiographic signs of otitis externa were present in two dogs. One dog had clinical signs of vestibular disease, whereas the other two dogs had no clinical evidence of ear disease. Otolithiasis may represent mineralized necrotic material of a current or previous case of otitis media.

Risk factors associated with development of seizures after use of iohexol for myelography in dogs: 182 cases (1998).

OBJECTIVE: To determine prevalence of seizures after use of iohexol for myelography and identify associated risk factors in dogs. DESIGN: Retrospective study. ANIMALS: 182 dogs that received iohexol for myelography in 1998. PROCEDURE: Medical records were reviewed for age, breed, sex, weight, dose and total volume of iohexol, injection site, number of injections, lesion type and location, total duration of anesthesia, duration from time of iohexol injection to recovery, presence and number of seizures, and whether surgery followed the myelogram. RESULTS: 39 (21.4%) dogs had at least 1 generalized seizure during or after myelography. Injection site was strongly associated with prevalence of seizures, and risk of seizure was significantly higher after cerebellomedullary injections, compared with lumbar injections. Mean total volume of iohexol administered to dogs that had seizures was significantly higher, compared with that administered to dogs that did not have seizures, although dosage did not differ between groups. Weight was significantly correlated with risk of seizure, and dogs that weighed > 20 kg (44 lb) had higher prevalence of seizures than dogs that weighed < 20 kg. CONCLUSIONS AND CLINICAL RELEVANCE: It is preferential to administer iohexol via the L5-6 intervertebral space to minimize the risk of seizures. Higher prevalence of seizures in large dogs, compared with smaller dogs, may be caused by administration of larger total volumes of contrast agent per volume of CSF.