THE USE OF99mTc RADIOAEROSOL VENTILATION AND MACROAGGREGATED ALBUMIN PERFUSION IMAGING FOR THE DETECTION OF PULMONARY EMBOLI IN THE DOG

This study was undertaken to design protocol for use of radioaerosol of technetium-99m-labeled diethylenetriaminepentacetic acid (^99mTc-DTPA) for ventilation imaging as clinical tool in the dog and to evaluate imaging characteristics in both normal dogs and dogs with simulated pulmonary embolism. Clearance of the 99mTc-DTPA radioaerosol from the lung was also evaluated. Six normal dogs were used in two phases: (1) as their own controls and (2) during pulmonary artery occlusion using Swan-Ganz catheter. Radioaerosol ventilation images were obtained and rate of clearance from normal and occluded lungs determined. Perfusion studies using technetium-99m-macroaggregated albumin (^99mTc-MAA) immediately followed. Clearance half-times (T_1/2) were found to be significantly increased (p < 0.05) in acutely occluded lungs; however, the small magnitude of this change was visually difficult to detect on the ventilation images. Good quality initial ventilation and perfusion images were obtained and provided ready evaluation of ventilation (V), perfusion (Q), and induced V/Q mismatches. A clinical case of pulmonary thromboembolic disease was also evaluated with diagnostic result, indicating that this method of V/Q scintigraphy can provide useful information in those clinical cases in which pulmonary thromboembolism is suspected.     

Ultrahigh-power semiconductor diode laser arrays

The power available from transistor-sized semiconductor diode lasers has increased rapidly in recent years, more than doubling every year. Continuous outputs of several watts and pulsed powers in the kilowatt range with 50 percent overall efficiency are now possible with these compact devices. These developments may signal the start of a technological advancement in optics comparable to the solid-state revolution in electronics 20 years ago.     

A COMPARISON OF PULMONARY ANGIOGRAPHY, DIGITAL SUBTRACTION ANGIOGRAPHY, AND 99mTc-DTPA/MAA VENTILATION-PERFUSION SCINTIGRAPHY FOR DETECTION OF EXPERIMENTAL PULMONARY EMBOLI IN THE DOG

The abilities of pulmonary angiography, digital subtraction angiography and ventilation-perfusion scintigraphy (V/Q) to detect experimental acute pulmonary emboli were evaluated in a group of 18 research dogs. Emboli were produced by forceful intravenous injection of clotted blood. In five dogs, emboli were labeled with thallium-201 prior to reinjection so that embolus position could be confirmed on scintigraphic studies.
Studies were independently reviewed by three observers. Results were combined so that the relative sensitivity, specificity, and accuracy of each imaging technique could be compared using chi-square and receiver-operating characteristic curve analysis. Digital subtraction angiography and V/Q studies proved to be significantly more specific and accurate than conventional pulmonary angiography. V/Q studies were uniformly of good to excellent quality while the quality of digital subtraction angiography studies was variable depending on the adverse effects of respiratory motion. It was concluded that ventilation-perfusion scintigraphy is the best available method to screen dogs suspected of having pulmonary thromboembolism.     

Nonsurgical management of ruptured urinary bladder in a critically ill foal

A small tear in the urinary bladder of a severely debilitated 4-day-old foal was managed with an indwelling urinary catheter connected to a urine collecting system. Fluid therapy, parenteral nutrition, and antimicrobial agents were used during the initial management of the ruptured bladder. Aseptic technique for catheter care and systemic administration of antimicrobial agents prevented the development of bacterial cystitis. Catheter management required constant monitoring, but the bladder defect was sealed within 5 days. Fungal arthritis caused by Candida tropicalis, immune-mediated anemia, diarrhea, constipation, venous thrombosis, and pneumonia were observed during 43 days of hospitalization. Although the foal died at 3 months of age, serum creatinine concentration and electrolyte values remained within normal limits during the 3-month period.