MAGNETIC RESONANCE IMAGING FINDINGS IN HORSES WITH RECENT ONSET NAVICULAR SYNDROME BUT WITHOUT RADIOGRAPHIC ABNORMALITIES     

SARAH N. SAMPSON  ROBERT K. SCHNEIDER  PATRICK R. GAVIN  CHARLES P. HO  RUSSELL L. TUCKER  ELIZABETH M. CHARLES 《Veterinary radiology & ultrasound》2009,50(4):339-346

Seventy-two horses with recent onset of navicular syndrome and normal radiographs were assessed. Horses underwent magnetic resonance (MR) imaging of both front feet. All abnormalities were characterized and the most severe abnormality identified, if possible. Abnormal signal intensity in the navicular bone was the most severe abnormality in 24 (33%) horses. Pathologic change in the deep digital flexor tendon was the most severe abnormality in 13 (18%) horses. Pathologic change in the collateral sesamoidean ligament was the most severe abnormality in 11 (15%) horses. Pathologic change in the distal sesamoidean impar ligament was the most severe abnormality in seven (10%) horses. Multiple abnormalities were observed in 13 (18%) horses in which an abnormality that was more severe than the others could not be determined. Abnormalities were not observed in the navicular bone or its supporting soft tissues in four (5%) horses. Fifty-six horses had abnormalities that were most severe in one limb; in 52 (93%) horses, the most severe abnormalities were in the foot of the most lame limb. In 7% (4/56) of horses, the most severe findings were in the opposite limb, and in 16 horses, the findings on both limbs were similar. MR imaging is a useful technique for evaluating horses with navicular syndrome and can differentiate between multiple abnormalities. This provides a more specific diagnosis which affects further treatment of the horse. Pathologic changes in different locations in the foot can cause similar clinical signs that, before MR imaging, were categorized as one syndrome.  相似文献   

RADIOGRAPHIC QUANTIFICATION OF TRACHEAL DIMENSIONS OF THE NORMAL THOROUGHBRED HORSE     

ANN CARSTENS  ROBERT M. KIRBERGER  RICHARD J. GRIMBEEK  CYNTHIA M. B. DONNELLAN  MONTAGUE N. SAULEZ 《Veterinary radiology & ultrasound》2009,50(5):492-501

Radiographic measurement of tracheal dimensions in the horse may be useful in evaluating upper and lower respiratory tract conditions due to the gradient of pressure changes between these areas. Lateral radiographs of the trachea of 15 normal sedated Thoroughbred horses were made at inspiration and expiration and magnification-corrected mean airway heights measured were, respectively: larynx: 5.89 and 5.86 cm; trachea at the third cervical vertebra (C3): 4.17 and 4.04 cm; at the fifth cervical vertebra (C5): 3.62 and 3.59 cm; at the first thoracic vertebra (T1): 3.4 and 3.23 cm; and carina: 3.85 and 4.12 cm. The ratio of airway height to nearby vertebral body lengths, at inspiration and expiration were, respectively: laryngeal height at C3: 0.56 and 0.56; tracheal height at C3: 0.4 and 0.39; at C5: 0.37 and 0.37; at T1: 0.59 and 0.59; and carina height: 0.91 and 0.94. The ratio of tracheal height to the thoracic inlet at inspiration and expiration was, respectively, 0.15 and 0.15. There was not a statistically significant association between airway diameter and phase of respiration. No association was found between tracheal height and body mass or height at the withers. Radiographic tracheal height can be measured independent of respiratory phase in sedated horses. It is suggested that the ratio of tracheal height to an adjacent bony landmark is more reliable for comparison between horses and tracheal height measurement should be made at C5, due to a lower standard deviation. If only thoracic radiographs are made, measurements of tracheal height at the thoracic inlet may be valuable.  相似文献   

Variation in the distribution of ocean shrimp (Pandalus jordani) recruits: links with coastal upwelling and climate change     

ROBERT W. HANNAH 《Fisheries Oceanography》2011,20(4):305-313

In this analysis, an atypical northward shift in the distribution of age‐1 ocean shrimp (Pandalus jordani) recruits off Oregon in 2000 and 2002–2004 was linked to anomolously strong coastal upwelling winds off southern Oregon (42°N latitude) in April–July of the year of larval release (t?1). This is the first clear evidence that strong upwelling winds can depress local recruitment of ocean shrimp. Regression analysis confirmed a long‐term negative correlation between log_e of ocean shrimp recruitment and April sea level height (SLH) at Crescent City, California, in the year of larval release, for both northern and southern Oregon waters. The regional pattern of ocean shrimp catches and seasonal upwelling winds showed that, although the timing of the spring transition as reflected in April SLH drives ocean shrimp recruitment success off Oregon generally, the strength and consistency of spring upwelling limits the distribution of large concentrations of ocean shrimp at the southern end of the northern California/Oregon/Washington area. A northward shift in 1999 and 2001–03 in the northern edge of this ‘zone of maximum upwelling’ is the likely cause of the weak southern Oregon recruitment and resulting atypical distribution of ocean shrimp observed off Oregon in 2000 and 2002–04, with a return to a more typical catch distribution as spring upwelling moderated in subsequent years. It is noted that a northward shift in the conditions that produce strong and steady spring upwelling winds is consistent with many predictions of global climate models under conditions of global warming.  相似文献