FIRST-PASS RADIONUCLIDE ANGIOGRAPHY IN THE DIAGNOSIS OF AORTOILIAC THROMBOEMBOLISM IN A HORSE

First-pass radionuclide angiography of the terminal aorta was performed in 3 normal horses and a 6-year old Standardbred intact male with aortoiliac thromboembolism. Thromboembolism caused chronic bilateral hind limb lameness, more severe in the right hind limb, was detected by rectal examination, and confirmed using transrectal ultrasonography. Using ^99mTc-HDP, first-pass radionuclide angiography was combined with hind limb and pelvis bone(delayed) scintigraphy and revealed marked reduction in blood flow through both external iliac arteries and absence of blood flow in the internal iliac arteries. Quantitative analysis showed a decreased activity in the right iliac vessels in the clinic patient consistent with reduced blood flow when compared to control horses. First-pass radio-nuclide angiography provided a method to obtain diagnostic images of the terminal aorta and branches and a method to diagnose aortoiliac thromboembolism in the horse.     

THE SONOGRAPHIC DIAGNOSIS OF CHRONIC PROLIFERATIVE SYNOVITIS IN THE METACARPOPHALANGEAL JOINTS OF A HORSE

Chronic proliferative synovitis is an insidious condition affecting the metacarpophalangeal joints of horses. It results in proliferation of the synovium in the dorsal pouch of the joint in question. Treatment involves surgical excision, thus confirmation of the lesion is important. Classically this has been achieved by means of positive-contrast arthrography, but this article addresses the attributes of ultrasonography, a less invasive imaging technique.     

ULTRASONOGRAPHIC DIAGNOSIS OF DIAPHRAGMATIC RUPTURE IN A HORSE

Real–time ultrasonography was used to confirm diaphragmatic rupture in a horse that developed pleural effusion following a traumatic event. Pleural effusion, a cranially displaced crus, and a cranially positioned sacculated loop of bowel were seen radiographically. The presence of gas–filled intestine cranial and dorsal to the diaphragm was detected by ultrasound imaging. The use of ultrasound and radiography in the diagnosis of diaphragmatic rupture is discussed.     

MAGNETIC RESONANCE IMAGING FOR THE DIAGNOSIS OF STRESS FRACTURES IN A HORSE

In humans, magnetic resonance (MR) imaging is the method of choice for the diagnosis of stress fractures. In this paper, bilateral stress fracture of the lateral condyle of the third metacarpal bone in a French trotter is described. Results of the radiographic, MR imaging, and histologic examinations are presented, with a focus on the MR signal abnormalities found. Based on this patient, the potential use of MR imaging for the diagnosis of stress fractures in horses is discussed.     

ULTRASONOGRAPHY AS AN AID IN THE DIAGNOSIS OF RENAL CELL CARCINOMA IN A HORSE

Clinical diagnosis of renal tumors in the horse has been difficult because the traditional diagnostic techniques are inadequate. Because of this shortcoming, early publications rarely reported antemortem diagnosis of primary renal tumors. Conventional radiographic techniques cannot effectively outline kidneys in the adult horse. With the advent of ultrasonography, a new dimension to the evaluation of the large-animal kidney has been introduced. Percutaneous diagnostic ultrasonography provides a noninvasive method of examining both kidneys. This report describes a 15 year-old Tennessee Walking Horse mare presented for evaluation of a mass in the sublumbar region, polyuria and polydipsia. Clinical examination and laboratory test results suggested intra-abdominal neoplasia. Two-dimensional ultrasonographic images of the mass were consistent with renal neoplasia. Histologic diagnosis of ultrasound-guided renal biopsy was renal tubular cell carcinoma.     

USE OF FIRST-PASS NUCLEAR ANGIOCARDIOGRAPHY TO DETECT LEFT-TO-RIGHT CARDIAC SHUNTS IN THE HORSE

First-pass nuclear angiocardiography was performed on 13 normal horses and 5 horses with confirmed left-to-right ventricular septal defects. Two methods of analyzing the ensuing pulmonary time-activity histograms for shunt recirculation through the lungs were evaluated: (1) pulmonary-to-systemic blood flow ratio (QP:QS), based on gamma variate modeling of the lung histogram, and (2) a simple count-ratio method (C2:C1). Normal values were QP:QS=1.17±0.04 and C2:C1=0.40±0.07. Values for the five horses with left-to-right shunts were QP:QS=2.94±0.13 and C2:C1=0.76±0.11. Both parameters showed significant differences (unpaired t -test; p <0.005) between the two groups, although separation was better with QP:QS.     

USE OF COMPUTED TOMOGRAPHY IN THE DIAGNOSIS OF A CEREBRAL ABSCESS IN A GOAT

A 7-month-old La Mancha doe was presented with a right head tilt and ventral strabismus while circling to the left. History and physical examination led to a tentative diagnosis of a cerebral abscess. Computed tomography revealed a large, complex mass with ring enhancement in the left cerebral hemisphere, supporting the diagnosis. Postmortem examination confirmed the cerebral abscess. Bacterial cultures yielded heavy growth of Actinomyces pyogenes.     

ULTRASONOGRAPHIC DIAGNOSIS OF A DEEP MUSCLE ABSCESS IN A HORSE

A deep muscle abscess was diagnosed in a horse with a clinical history of a painful swelling in the left gluteal region. The thick walled hypoechoic structure seen on presentation and the multiloculated hyperechoic mass seen on reevaluation are common Ultrasonographic appearances of abscesses. Ultrasonographic evaluation allowed characterization of a chronic mass with subsequent successful surgery and treatment.     

SPONTANEOUS RESOLUTION OF A PSEUDOANEURYSM IN A HORSE FOLLOWING ANGIOGRAPHIC DIAGNOSIS

Angiography in a horse was used to confirm a pseudoaneurysm of the dorsal metatarsal artery originating from trauma. Gradual clinical resolution of the pseudoaneurysm occurred within days following the procedure. A follow-up angiogram confirmed the clinical impression. An etiology of the spontaneous resolution is presented. Probable influences included technical factors of the injection procedure that caused prolonged presence of the contrast medium within the aneurysmal sac and factors that enhance thrombus formation during angiography.