首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 46 毫秒
1.
Computed tomography angiography, sonography, scintigraphy, and portography can be used to evaluate the portal vasculature to evaluate for a portosystemic shunt (PSS). Time‐of‐flight magnetic resonance angiography (TOF‐MRA) and contrast‐enhanced MRA (CE‐MRA) are other potentially useful techniques. The aim of this study was to evaluate CE‐MRA in 10 dogs suspected of having a PSS. Noncontrast MR images of the abdomen were obtained using a Siemens Symphony MR‐scanner (1.5 T) and a T1‐weighted FLASH‐3D sequence with a very short scan time (about 20 s). After injection of contrast medium, the initial sequence was repeated five times. The sequence with the best contrast medium filling of the portal vasculature was selected subjectively, subtracted from the initial survey image series, and a maximum intensity projection (MIP) of the subtraction data, in multiple views, was created. The cross‐sectional and MIP images were evaluated for abnormal portosystemic vasculature. A single PSS was identified and confirmed at surgery in all dogs. A portocaval shunt was found in five dogs, a portophrenic shunt in three dogs, a portoazygos shunt in one, and a central divisional intrahepatic shunt in one other dog. Based on our results, CE‐MRA is a useful tool for imaging abdominal and portal vasculature and for the diagnosis of a PSS.  相似文献   

2.
We describe the technique for in vivo cardiac‐gated magnetic resonance imaging (MRI) in normal dogs and its application in two dogs with a large right atrial tumor. The dogs with a cardiac tumor were also imaged using contrast‐enhanced magnetic resonance angiography (CE‐MRA). Cardiac‐gated MRI and CE‐MRA are both feasible in animals with short acquisition times compatible with breath‐hold imaging under anesthesia, and provide detailed two‐ and three‐dimensional (3D) depiction of the cardiac anatomy and great vessels with or without contrast medium. Although cardiac MRI will not replace echocardiography, it is a powerful alternative technique to use when knowledge of the 3D anatomy of the vasculature is required, when precise volume measurements are needed or when myocardial characterization is indicated. As opposed to contrast‐enhanced computed tomography angiography, cardiac MRI does not use ionizing radiation or iodinated contrast medium.  相似文献   

3.
Although horses are affected by cranial nerve disease, our understanding of these structures' imaging anatomy is limited, and the optimal modality for imaging of each of these nerves is unclear. The aim of this study was to describe the imaging appearance of the equine cranial nerves on high‐resolution 1.5T magnetic resonance imaging (MRI) and computed tomography (CT) scans of a cadaver head, and with these as standards, examine the utility of MRI and CT performed in clinical cases. High‐resolution MRI and CT images were prospectively acquired of the head of a normal Thoroughbred gelding following euthanasia. Ten clinical cases undergoing high‐field MRI under general anaesthesia and 10 clinical cases undergoing CT in the standing horse under sedation were retrospectively evaluated by three reviewers to assess cranial nerve visibility. On high‐resolution, thin‐slice, MRI scans of the normal cadaver head, each of the 12 cranial nerves and their topographic location could be appreciated. On high‐resolution cadaver CT, cranial nerves II, V and VII were clearly visible, but others were less easily identified; osseous structures were clearly visualised. Clinical MRI and CT allowed for variable visualisation of the cranial nerves, dependent on the sequence and the orientation of scan planes. High‐field MRI allowed excellent visualisation of equine cranial nerves, whereas CT allowed for more detailed visualisation of the osseous canals and foramina. In live horses, the ability to identify all 12 nerves is challenging with either MRI or CT; however, high‐field MRI enables better visualisation of the nerve bundles than CT.  相似文献   

4.
Contrast‐enhanced multiphase magnetic resonance angiography (CE‐MRA) was used in 17 dogs with a suspected congenital portal vascular anomaly. Portal vascular anomalies were identified in 16 of the 17 dogs. Eleven had a single intrahepatic portocaval shunt (two central divisional, three right divisional, and six left divisional), one dog had a double intrahepatic portocaval shunt, one dog had a hepatic arteriovenous malformation, one dog had a complex intrahepatic porto‐caval shunt. Two dogs had an extrahepatic portosystemic shunt and no shunt was identified in one dog. Total imaging time was <10 min and image quality was good to excellent in all dogs. Portal CE‐MRA is a feasible, fast and non invasive technique to diagnose portal vascular anomalies in dogs, with a large field‐of‐view and good anatomic depiction of the abnormal vessels. Based on these results, CE‐MRA is an efficient imaging technique for the diagnosis of portal vascular anomalies in dogs.  相似文献   

5.
The appearance of the equine metacarpophalangeal (MCP) joint on high‐field (1.5 T) vs. low‐field standing (0.27 T) magnetic resonance (MR) images was evaluated. Objectives were (1) to describe the MR appearance of anatomic structures of clinical interest on images of the equine MCP joint obtained from 20 equine cadaver limbs from horses without lameness using high‐field and low‐field systems, (2) to categorize the clarity of appearance of anatomic structures on low‐field MR images in comparison to high‐field images as a gold standard. We found that larger anatomic structures were visible with sharp margins on both high‐ and low‐field images, smaller structures were less distinct on low‐field images and therefore interpretation of smaller structures on low‐field images must be done with care.  相似文献   

6.
Eight neurologically normal beagles were imaged using three-dimensional (3D) time-of-flight magnetic resonance angiography (MRA) in a 3 T magnetic resonance scanner. Four of the eight dogs were also imaged using a 1 T unit for comparison. Ten intracranial arteries were consistently identified at 3 T: external and internal carotid, basilar, vertebral, rostral cerebral, middle cerebral, caudal cerebral, rostral communicating, caudal communicating, and ventral spinal arteries. Only four were reliably identified at 1 T with diagnostic spatial and contrast resolution. At 3 T, vessels as small as 1 mm were reliably detected. Vessel conspicuity was superior using the 3 T system. An anatomic atlas of the canine circulus arteriosus cerebri using a 3 T scan was constructed. The effect of MRA parameters on vascular spatial resolution and conspicuity are reviewed.  相似文献   

7.
Reasons for performing study: To determine the reliability of 2 magnetic resonance imaging (MRI) systems for detection of cartilage and bone lesions of the equine fetlock. Objectives: To test the hypotheses that lesions in cartilage, subchondral and trabecular bone of the equine fetlock verified using histopathology can be detected on high‐ and low‐field MR images with a low incidence of false positive or negative results; that low‐field images are less reliable than high‐field images for detection of cartilage lesions; and that combining results of interpretation from different pulse sequences increases detection of cartilage lesions. Methods: High‐ and low‐field MRI was performed on 19 limbs from horses identified with fetlock lameness prior to euthanasia. Grading systems were used to score cartilage, subchondral and trabecular bone on MR images and histopathology. Sensitivity and specificity were calculated for images. Results: High‐field T2*‐weighted gradient echo (T2*W‐GRE) and low‐field T2‐weighted fast spin echo (T2W‐FSE) images had high sensitivity but low specificity for detection of cartilage lesions. All pulse sequences had high sensitivity and low–moderate specificity for detection of subchondral bone lesions and moderate sensitivity and moderate–high specificity for detection of trabecular bone lesions (histopathology as gold standard). For detection of lesions of trabecular bone low‐field T2*W‐GRE images had higher sensitivity and specificity than T2W‐FSE images. Conclusions: There is high likelihood of false positive results using high‐ or low‐field MRI for detection of cartilage lesions and moderate–high likelihood of false positive results for detection of subchondral bone lesions compared with histopathology. Combining results of interpretation from different pulse sequences did not increase detection of cartilage lesions. MRI interpretation of trabecular bone was more reliable than cartilage or subchondral bone in both MR systems. Potential relevance: Independent interpretation of a variety of pulse sequences may maximise detection of cartilage and bone lesions in the fetlock. Clinicians should be aware of potential false positive and negative results.  相似文献   

8.
Reasons for performing study: To date, few reports exist comparing magnetic resonance imaging (MRI) and computed tomography (CT) for imaging of the equine distal limb, yet clinicians are required to decide which modality to use regularly. Objectives: To report and compare anatomic visualisation scores obtained for CT, contrast enhanced CT (CECT) and standing low‐field MRI (LFMRI) in the equine foot. Hypothesis: Anatomic visualisation score discrepancies would exist between CT, CECT and LFMRI. Methods: Images of 22 lame horses (31 limbs) undergoing both CT and LFMRI of the foot were reviewed. When available, CECT images were reviewed. The deep digital flexor tendon (DDFT) was categorised into proximal to distal levels (A–D), structures were assigned visualisation scores (Grades 0–3) and technique comparisons were made using the paired marginal homogeneity test. Results: Computed tomography and LFMRI had similar visibility scores for the navicular bone, middle phalanx, DDFT‐B, collateral ligaments of the distal interphalangeal joint and collateral sesamoidean ligament of the navicular bone. The proximal and distal phalanx had lower visibility scores with LFMRI. The distal DDFT (C–D), distal sesamoidean impar ligament and synovial structures had higher scores with LFMRI. Contrast enhanced CT lowered DDFT and collateral sesamoidean ligament scores and raised distal interphalangeal synovium CT visualisation scores. Conclusions and potential relevance: Visualisation scores differ depending on imaging technique and anatomic structure of interest. This information increases our understanding of the limitations of CT, CECT and LFMRI to visualise anatomy in clinical cases.  相似文献   

9.
  相似文献   

10.
Alberto  Arencibia  DVM  PhD  Jose M.  Vázquez  DVM  PhD  Raduán  Jaber  DVM  Francisco  Gil  DVM  PhD  Juan A.  Ramiírez  MD  PhD  Miguel  Rivero  DVM  Nelson  González  DVM  PhD  Erik R.  Wisner  DVM 《Veterinary radiology & ultrasound》2000,41(4):313-319
The purpose of this investigation was to define the magnetic resonance imaging anatomy of the rostral part of the equine head. 10 mm-thick, T1-weighted images of two isolated equine cadaver heads were obtained using a 1.5 Tesla magnet and a body coil. MR images were compared to corresponding frozen cross-sections of the cadaver head. Relevant anatomic structures were identified and labeled at each level. The resulting images provided excellent anatomic detail of the oral and nasal cavities, paranasal sinuses and associated structures. Annotated MR images from this study are intended as a reference for clinical MR imaging studies of the equine head.  相似文献   

11.
Computed tomography angiography is widely used for the assessment of various mesenteric vascular and bowel diseases in humans. However, there are only few studies that describe CT angiography application to mesenteric vessels in dogs. In this prospective, experimental, exploratory study, the mesenteric vasculature and enhancement pattern of the intestinal wall were evaluated on triple‐phase CT angiography, and improvement of the visibility of vasculature was assessed on multiplanar reformation, maximum intensity projection, and volume rendering technique. After test bolus scanning at the level of the cranial mesenteric artery arising from the aorta, mesenteric CT angiography was performed in 10 healthy, male, Beagle dogs. Scan delay was set based on time‐to‐attenuation curves, drawn by placing the regions of interest over the aorta, intestinal wall, and cranial mesenteric vein. Visualization and enhancement of mesenteric arteries and veins were evaluated with multiplanar reformation, maximum intensity projection, and volume rendering techniques. The degree of intestinal wall enhancement was assessed on the transverse images in precontrast, arterial, intestinal, and venous phases. Pure arterial images were obtained in the arterial phase. Venous phase images allowed good portal vascular mapping. All CT angiography images were of high quality, allowing for excellent visualization of the anatomy of mesenteric vasculature including the small branches, particularly on maximum intensity projection and volume rendering technique. Distinct contrast enhancement of the intestinal wall was observed in both intestinal and venous phases. Findings indicated that this technique is feasible for the evaluation of mesenteric circulation in dogs.  相似文献   

12.
Alberto  Arencibia  DVM  PhD  Jose M.  Vazquez  DVM  PhD  Juan A.  Ramirez  MD  PhD  Gregorio  Ramirez  DVM  PhD  Jose M.  Vilar  DVM  Miguel A.  Rivero  DVM  Santiago  Alayon  MD  Francisco  Gil  DVM  PhD 《Veterinary radiology & ultrasound》2001,42(5):405-408
The purpose of this investigation was to define the magnetic resonance (MR) imaging appearance of the brain and associated structures of the equine head. MR images were acquired in oblique dorsal (T2-weighted), sagittal (T1-weighted), and transverse planes (T2-weighted), using a magnet of 1.5 Tesla and a human body coil. Relevant anatomic structures were identified and labeled at each level. The resulting images provided excellent anatomic detail of the cranioencephalic structures. Annotated MR images from this study are intended as a reference for clinical imaging studies of the equine head, specially in the diagnosis of brain diseases in the horse.  相似文献   

13.
A 12-year-old, neutered female, Siberian Husky dog presented with a hind limb weakness of one month duration. To facilitate making a diagnosis multiple imaging modalities were performed. These modalities included radiography, ultrasonography, magnetic resonance imaging (MRI), magnetic resonance angiography (MRA) and selective angiography of the abdominal aorta. In this dog, the MRI/MRA studies provided the first documentation of the external iliac thrombi and the collateral circulation via the lumbar arteries. At necropsy, an aortoiliac thrombus caused by a mineralized arteriosclerotic plaque was noted.  相似文献   

14.
In humans, contrast-enhanced magnetic resonance angiography (CE-MRA) is a documented method to quantitatively and qualitatively evaluate renal vessels. It offers a safer alternative to computed tomography angiography. The aim of this study was to establish a renal MRA protocol in dogs using a 3D multiphase Fast Spoiled Gradient Recalled echo CE-MRA sequence (3D FSPGR CE-MRA). We used an elliptical centric ordering of k -space to acquire the contrast-sensitive data faster. Four to five consecutive 3D dorsal slabs, encompassing both kidneys, could be acquired in 40–65 s. The renal arterial and venous phases were obtained separately during phases 1 or 2, and 2 or 3, respectively without the need for any contrast medium bolus timing. The renal arteries and veins were clearly visualized. In conclusion, multiphase FSPGR 3D CE-MRA with an elliptical centric k -space ordering allows distinguishing renal arterial and venous phases in dogs, and can be used as a noninvasive diagnostic imaging alternative to map renal vessels in this species. Potential applications include the screening of renal donors in renal transplantation programs, and the pretreatment evaluation of animals with invasive renal neoplasia or renal vascular anomalies when surgery or embolization are contemplated.  相似文献   

15.
We describe a 5-year-old castrated male dog suspected hypoglycemic encephalopathy that was evaluated by using diffusion-weighted imaging (DWI). The dog experienced hypoglycemia after prolonged generalized and continued partial seizures. In the acute phase, DWI showed hyperintensity in the left temporal lobe. After about a month, DWI maintained hyperintensity, and left middle cerebral artery dilation was noted on magnetic resonance angiography (MRA). In the chronic phase, the left temporal lobe lesion was replaced by cerebrospinal fluid. In humans, it was reported that cortical laminar necrosis (CLN) with hypoglycemic encephalopathy presents hyperintensity in the cerebral cortex on DWI and increased vascularity of the middle cerebral artery branches on MRA. In conclusion, DWI has detected CLN in a dog suspected hypoglycemic encephalopathy.  相似文献   

16.
The equine head is an anatomically highly complex area affected by a range of disorders, making the diagnosis of head conditions challenging. Imaging techniques play a crucial role in the diagnostic work-up of head disorders. Tomographic imaging methods, such as computed tomography (CT) and magnetic resonance imaging (MRI) are particularly useful in avoiding problems associated with superimposition of multiple structures in this highly complex region. Both techniques are becoming more widely available in equine medicine. However, the choice between CT and MRI for imaging the equine head is not always straightforward. Each modality has advantages and disadvantages in terms of practicality, costs and diagnostic value for particular problems. The aim of this review is to describe the application of CT and MRI for imaging the equine head and to provide a practical guide for their use in different anatomical structures and clinical indications. This should allow the equine practitioner to make an informed decision on which modality to choose.  相似文献   

17.
This study was undertaken to investigate differences in protein expression between high‐ and low‐motility sperm of swamp buffalo. The research used two‐dimensional gel electrophoresis (2DE) coupled to matrix‐assisted laser desorption/ionization time‐of‐flight tandem mass spectrometry (MALDI‐TOF/TOF‐MS) to analyse the different proteins. The results showed 18 different expression protein spots between high‐ and low‐motility buffalo sperm; eight of these proteins were up‐regulated in low‐motility sperm, five were down‐regulated, one deleted and four proteins specifically expressed. Finally, four proteins were successfully identified by MS as belonging to three unique proteins; they are outer dense fibre of sperm tails protein 2 (ODF2), ATP synthase subunit alpha (ATP5A1) and succinyl‐CoA synthetase subunit beta (SUCLG2). In summary, these results help to develop an understanding of the molecular mechanisms associated with low‐motility sperm and provide clues for finding molecular markers associated with sperm motility.  相似文献   

18.
Computed tomography (CT), magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) were performed on a dog with a two year history of unilateral exophthalmos occurring two years following head trauma. On CT images, an expansile enhancing mass was present along the right intracranial cavernous sinus and extended through the orbital fissure into the retrobulbar space. With MRI, the structure appeared as a signal void due to the presence of rapidly flowing blood. Gadolinium enhancement of the adjacent brain was not present. A vascular origin of the lesion was confirmed with MRA. Based on the CT and MRI findings, the enlarged cavernous sinus and associated ophthalmic plexus were believed to represent an arterialized aneurysm, most likely the result of traumatic arteriovenous fistulization. Treatment consisted of surgical enucleation. At the time of this report, 29 mouths later, the dog remains free of clinical signs.  相似文献   

19.
Osteoarthritis of the metacarpophalangeal joint is common cause of lameness in equine athletes, and is hallmarked by articular cartilage damage. An accurate, noninvasive method for measuring cartilage thickness would be beneficial to screen for cartilage injury and allow for prompt initiation of interventional therapy. The objective of this methods comparison study was to compare computed tomographic arthrography (CTA), magnetic resonance imaging (MRI), and magnetic resonance arthrography (MRA) measurements of articular cartilage thickness with gross measurements in the metacarpophalangeal joint of Thoroughbred horses. Fourteen cadaveric, equine thoracic limbs were included. Limbs were excluded from the study if pathology of the metacarpophalangeal articular cartilage was observed with any imaging modality. Articular cartilage thickness was measured in nine regions of the third metacarpal bone and proximal phalanx on sagittal plane MRI sequences. After intra‐articular contrast administration, the measurements were repeated on sagittal plane MRA and sagittal CTA reformations. In an effort to increase cartilage conspicuity, the volume of intra‐articular contrast was increased from 14.5 ml, to maximal distention for the second set of seven limbs. Mean and standard deviation values were calculated, and linear regression analysis was used to determine correlations between gross and imaging measurements of cartilage thickness. This study failed to identify one imaging test that consistently yielded measurements correlating with gross cartilage thickness. Even with the use of intra‐articular contrast, cartilage surfaces were difficult to differentiate in regions where the cartilage surfaces of the proximal phalanx and third metacarpal bone were in close contact with each other.  相似文献   

20.
Multidetector‐row computed tomographic contrast angiography (MDCTA) is routinely employed to investigate vascular masses in human patients but, to date, the use of this technique to investigate an aneurysmal mass has not been reported in an equine case. The potential of MDCTA to investigate a right‐sided parapharyngeal mass in a 6‐week‐old Thoroughbred foal was therefore investigated. A 4‐slice helical computed tomography scanner was used on a superficial, firm, ovoid mass yielding arterial blood on fine needle aspiration. MDCTA enabled identification of the vessels involved thus assisting in forming a diagnosis based on the morphology of the lesion and aided surgical planning. Histology confirmed the presence of mural thrombus and calcification within the smooth muscle wall consistent with a true aneurysm. MDCTA provided additional information to conventional imaging in this case of vascular masses of the head and neck. The technique therefore has the potential to improve diagnosis and assist in the management of such lesions.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号