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1.
A stifle magnetic resonance (MR) imaging protocol was developed based on the appearance of the cruciate ligaments and menisci in normal dogs. Proton density images were subjectively considered to have the highest likelihood of detecting a meniscal lesion. Following this initial evaluation, the accuracy of high-field MR imaging to detect meniscal tears in dogs was evaluated in 11 dogs suffering from naturally occurring cranial cruciate ligament rupture. Dogs underwent MR imaging of the affected stifle before surgery. MR imaging and surgical findings were assessed independently, and then compared. Five tears of the medial meniscus were correctly diagnosed with MR imaging and 19 normal menisci were accurately characterized as such, based on MR images. In one medial meniscus, changes consistent with meniscal degeneration were seen on MR images but this was not seen at surgery. With regard to the lateral meniscus, one false positive diagnosis of a tear was made and this likely represented a normal variation. One other lateral meniscus had changes consistent with meniscal degeneration but, as with the similar lesion seen in the medial meniscus, this was not confirmed surgically. The global sensitivity of MR imaging for the diagnosis of a meniscal tear was 100% and the specificity was 94%. High-field MR imaging is a reliable method to diagnose meniscal tears preoperatively and this may be useful in selecting the surgical approach to clinically abnormal joints and may decrease the need for arthrotomy.  相似文献   

2.
BACKGROUND: Diagnosis of central nervous system (CNS) abnormalities in dogs can be challenging antemortem. Historically, cerebrospinal fluid (CSF) analysis has been used for routine diagnostic evaluation of animals with suspected neurologic disease; however, with increasing availability of magnetic resonance (MR) imaging, the need for concurrent CSF analysis may be questioned. OBJECTIVE: The purpose of this study was to retrospectively assess and compare the diagnostic information contributed from MR imaging and CSF analysis in a population of dogs presenting with neurologic disease. METHODS: Results of concurrent MR imaging and CSF analysis were evaluated in dogs presented for neurologic diseases. Based on clinical diagnosis, the sensitivity of CSF analysis and MR imaging for detecting a nervous system abnormality was calculated. Dogs with diagnoses confirmed by other diagnostic modalities were also evaluated separately. RESULTS: A total of 256 dogs were included in the study. For clinical diagnoses in which abnormalities were expected, MR imaging abnormalities were found in 89% and CSF abnormalities in 75% of dogs; CSF abnormalities were more common than MR imaging abnormalities only in inflammatory CNS disease. The majority of CSF abnormalities were nonspecific; an etiologic diagnosis was determined in only 2% of CSF samples. MR imaging excelled in detecting structural disorders, revealing 98% of vertebral abnormalities. In confirmed cases (n = 55), 76% of MR images and 9% of CSF samples were diagnostic. When intervertebral disk disease (IVDD) and vertebral malformation were excluded from analysis (n = 16 remaining), 25% of MR images and 6% of CSF cytology results were highly indicative of the confirmed diagnoses; CSF titer results provided the diagnosis in 25% of these cases. CONCLUSION: CSF analysis may not be necessary when MR findings of IVDD or vertebral malformation/instability are obvious; however, when the cause of neurologic disorder is uncertain, concurrent MR imaging and CSF analysis provides the greatest assistance in establishing a clinical diagnosis.  相似文献   

3.
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4.
In humans affected with inflammatory myopathies, regions of altered signal intensity are found on magnetic resonance (MR) images of affected muscles. Although electromyography (EMG) is more practical for muscle disease evaluation, and a muscle biopsy is the only manner in which a definitive diagnosis can be made, MR imaging has proven useful if a specific anatomic localization is difficult to achieve. Three dogs with focal inflammatory myopathy diagnosed with the assistance of MR imaging are discussed and the findings are compared with those found in humans. MR images of the affected muscles in each dog were characterized by diffuse and poorly marginated abnormal signal on T1- and T2-weighted images. Marked enhancement was noted in these muscles after contrast medium administration. An inflammatory myopathy was confirmed histologically in all three dogs. A good association existed between the MR images and muscle inflammation identified histopathologically. MR imaging may be a useful adjunctive procedure for canine inflammatory myopathies.  相似文献   

5.
Two Lhasa Apsos were diagnosed with lissencephaly based on MR imaging and clinical findings. Histologic confirmation of the diagnosis was obtained in one dog. The MR imaging appearance of the brain in 2 Lhasa Apsos with lissencephaly was of a smooth cerebral surface and a thick neocortex with an absence of the corona radiata. This correlated very well with the histopathologic findings in the dog. Our findings, together with the histopathologic features reported previously, are most consistent with Lhasa Apsos having the canine equivalent of human classical lissencephaly. MR is the imaging modality of choice for antemortem diagnosis of canine lissencephaly.  相似文献   

6.
A bone bruise is a magnetic resonance (MR) imaging sign thought to signify acute traumatic microfracture of trabecular bone with hemorrhage and edema in the marrow that may occur without grossly visible disruption of the adjacent cortices or overlying cartilage. In approximately 75% of people with acute anterior-cruciate ligament tears, bone bruises are detected in characteristic locations within the femur and tibia and are best seen as high-signal lesions using fat-suppression sequences. We questioned whether this is a component of naturally acquired stifle lameness in dogs and obtained short-tau inversion recovery (STIR) images of six dogs with stifle lameness. High-signal STIR lesions were detected in five of six (83%) dogs and eight of 12 (67%) limbs. We observed these lesions deep to the intercondylar fossa of the femur and intercondylar eminence of the tibia, which are atypical locations in people. High-signal STIR lesions were detected in dogs with only synovitis, partial tear of the cranial cruciate ligament (CCL) and complete tear of the CCL. One of these lesions was seen in the lateral tibial condyle, a typical location in humans with acute anterior cruciate ligament tear. As the MR imaging appearance of stress fractures and bone bruises are similar, and the high-signal STIR lesions are at attachment sites of the CCL, this finding may be due to stress disease or other unknown causes, rather than bone bruising. High-signal STIR lesions may be a common sign in naturally acquired canine stifle disease, but the pathogenesis, prognostic and diagnostic values need further investigation.  相似文献   

7.
Sonography is commonly used for diagnosis of desmopathy of the proximal part of the suspensory ligament in horses. However, magnetic resonance (MR) imaging has been stated to be superior for detecting disease and localizing lesions. In this retrospective study of 39 horses or 46 hind limbs with lameness due to proximal plantar metatarsal pain, the clinical and diagnostic findings are discussed and sonography and MR imaging compared for examination of the proximal part of the suspensory ligament. With MR imaging interpreted as the clinical gold standard, desmopathy of the proximal part of the suspensory ligament was diagnosed in 21 hind limbs, proximal plantar metatarsal pain of unknown cause in 12, an osseous injury at the origin of the suspensory ligament in four and a condition unrelated to the suspensory ligament in nine. Based on these findings, sonography had a sensitivity of 0.77 and 0.66 and specificity of 0.33 and 0.31 for diagnosing proximal suspensory desmopathy and for accurately localizing lesions, respectively. MR imaging changes consistent with proximal suspensory desmopathy were signal hyperintensities and an increase in cross-sectional area compared with the contralateral limb. Anesthesia of the deep branch of the lateral plantar nerve is not specific neither for proximal suspensory desmopathy, as conditions unrelated to the suspensory ligament were diagnosed, nor for diagnosis of proximal plantar metatarsal pain, as conditions outside the proximal plantar metatarsal region were also diagnosed.  相似文献   

8.
In humans that have undergone cervical diskectomy, magnetic susceptibility artifacts are often found on postoperative magnetic resonance (MR) images of the affected region. In some patients, these artifacts complicate image interpretation, while in others the artifacts lead to a false diagnosis of spinal cord compression. We describe two dogs and one cat that had susceptibility artifacts visible in postoperative MR images. In each patient, multiple, small-to-large, distinct, magnetic susceptibility artifacts were visible along the surgery site. In both dogs, interpretation was impossible and subsequently computed tomography (CT) was performed. During CT, no cause for the MR artifact was identified. The most likely source of the artifact is microscopic metal fragments from the burr, suction tip or other surgical instruments, but other possible causes include hemorrhage or paramagnetic suture material. These artifacts may cause difficulty in interpretation or suggest a clinical problem. MR imaging therefore might not be the most appropriate examination for patients following certain types of surgery due to the possibility of susceptibility artifacts. Although this artifact probably is common in the postoperative patient, the frequency that this finding will prevent accurate diagnosis is unknown.  相似文献   

9.
Our aim was to characterize the magnetic resonance (MR) imaging features of canine disc extrusion accompanied by epidural hemorrhage or inflammation. We correlated the imaging characteristics of this type of disc extrusion in 46 dogs and compared these features with clinical signs and pathologic findings. Data from 50 control dogs with MR imaging features of a disc extrusion with no associated hemorrhage or inflammation, characterized by a T2‐hypointense extradural mass, were used for comparison of the relative location of the two types of lesions and prognosis. Disc extrusion causing epidural hemorrhage or inflammation is more common in the caudal aspect of the lumbar spine than disc extrusions that do not cause signs of hemorrhage or inflammation (P<0.05) in MR images. In dogs with disc extrusion and associated epidural hemorrhage or inflammation, there was no association between MR imaging features and signalment, the presence or absence of hemorrhage, or pathologic findings. The appearance of the lesion created by disc extrusion with epidural hemorrhage and inflammation encompasses a wide variety of imaging features, likely related to the duration of the hemorrhage and associated inflammatory changes. In 10 of 46 dogs these secondary changes masked identification of the disc extrusion itself in the MR images. An awareness of the variety of MR imaging features of disc extrusion accompanied by extradural hemorrhage or inflammation is important to avoid making an incorrect diagnosis and to facilitate a proper surgical approach. The prognosis of dogs with disc extrusion accompanied by hemorrhage or inflammation does not appear to be different than for dogs with disc extrusion and without imaging signs of epidural hemorrhage or inflammation.  相似文献   

10.
Reasons for performing study: The metacarpo/metatarsophalangeal (MCP/MTP) joint is a common site of lameness in the Thoroughbred racehorse. Radiographs may fail to show pathology consistent with the degree of lameness. With a high incidence of stress fractures occurring in the distal third metacarpal/metatarsal (MC3/MT3) condyles and proximal phalanx, a definitive diagnosis as to the nature of the pathology is essential. Objective: To describe the low‐field magnetic resonance imaging (MRI) findings in Thoroughbred racehorses with MCP/MTP joint pain scanned under standing sedation. Methods: The MR images and clinical records of all Thoroughbred racehorses undergoing MRI of the MCP/MTP joint between October 2006 and August 2010 were reviewed. A total of 168 joints from 131 horses were selected for inclusion. The MRI finding considered most significant in the lame (or lamest) limb was noted. Results: Diagnostic quality images were obtainable in 97.8% of horses. The most common finding was palmar/plantar osteochondral disease in MC3/MT3 (54.9% of horses). Incomplete condylar fracture was diagnosed in 19.8% of horses, with the lateral condyle predominating. An incomplete sagittal fracure of P1 was diagnosed in 14.5% of horses and 11.4% were diagnosed with ‘dorsal joint disease’. Other findings included transverse MC3 stress fractures (1.5%), soft tissue injuries (12.2%) and proximal phalangeal ‘contusions’ (3.8%). No significant bone/soft tissue injury was detected in 5.4% of cases. Conclusions: Standing MRI can detect a spectrum of disease within the MCP/MTP joints of racehorses. The procedure is well tolerated and may lead to a definitive diagnosis where radiographic imaging is inconclusive. Potential relevance: A total of 35.8% of cases had MRI findings consistent with fracture pathology, which could not be confirmed radiographically at the time of the MRI examination. This has important therapeutic and prognostic implications and may help to prevent catastrophic injury.  相似文献   

11.
Distal phalanx fractures are well documented in adult horses, but our knowledge of such fractures in foals is limited. Recent studies showed a high incidence of distal phalanx palmar process (PP) fractures in foals, the aetiology is not yet known. Several hypotheses have been suggested as possible causes, including uneven compressive forces, unequal forces from the deep digital flexor tendon, composition and shape of the PP, and conformation. A better understanding of the aetiology and predisposing factors requires further research. Radiography is the commonly used imaging modality for diagnosis of such fractures; however, those fractures might be missed on routine radiographic projections. In order to have a high probability of identifying fractures, a series of 5 radiographs including the oblique views is required. This article reviews the incidence of distal phalanx PP fractures and discusses the diagnosis of such fractures.  相似文献   

12.
Intracranial neoplasia   总被引：1，自引：0，他引：1  
A diagnosis of intracranial neoplasia in companion animals may be made by computed tomography (CT) or magnetic resonance imaging (MRI). MRI is the better method for detecting and characterizing intracranial tumors because of its superior depiction of soft tissues and relative lack of degrading artifacts, intracranial tumors may be characterized by distinct features; a systematic evaluation of these features on CT or MRI images may help to identify specific tumor types. In this article, guidelines for formulating differential diagnoses based on these imaging criteria will be discussed. Technical recommendations and protocols for CT and MR imaging will also be provided.  相似文献   

13.
The relative sensitivity of radiography, computed tomography, and magnetic resonance imaging for detecting palmar process fractures of the distal phalanx in foals was determined and the imaging findings were compared with histomorphologic evaluations of the palmar processes. Compared to radiography, computed tomography and magnetic resonance imaging did not improve the sensitivity for detection of palmar process fractures. Statistical agreement for palmar process fracture diagnosis was excellent among the three imaging modalities. Histomorphologic evaluations were more sensitive for diagnosis of palmar process fracture than any of the imaging modalities. Three-dimensional image reconstructions and volume measurements of distal phalanges and palmar process fracture fragments from computed tomography studies provided more complete anatomical information than radiography. Magnetic resonance imaging confirmed that the deep digital flexor tendon insertion on the distal phalanx is immediately axial to the site where palmar process fractures occur, and differentiated cartilage, bone, and soft tissue structures of the hoof.  相似文献   

14.
Spirocerca lupi is a nematode infecting dogs in tropical and subtropical areas. Aberrant S. lupi migration to different body organs, including the spinal cord, has been documented. To date, the diagnosis of aberrant spinal cord migration was made at post-mortem examination or as an incidental finding, during spinal surgery. We describe two dogs with acute asymmetric paraparesis that were subsequently diagnosed with spinal cord spirocercosis. In magnetic resonance (MR) images of the spine, T2 hyperintense lesions were seen in the spinal cord of both dogs. The lesions appeared isointense on T1-weighted images and focal enhancement was detected after gadolinium administration. The MR imaging findings were compatible with focal inflammation, presumably along the parasite migration tract. Gross and microscopic pathologic findings confirmed the diagnosis of aberrant spinal intramedullary migration of S. lupi in one dog, and in the other dog, the clinical and imaging findings were supportive of this diagnosis.  相似文献   

15.
Equine laminitis is a severely debilitating disease. There is a poor understanding of the underlying pathophysiology, and traditional imaging modalities have limited diagnostic capacity. High field strength magnetic resonance (MR) imaging allows direct visualization of the laminae, which other modalities do not. This would prove useful both in assessment of clinical patients and in further investigation into the pathophysiology of the disease. The objective of this study was to characterize the anatomic changes within the equine foot associated with the initial active stage of laminitis. Images obtained using a 4.7 T magnet were compared with digital radiographs using histologic diagnosis as the reference standard. Objective measurements and subjective evaluation for both modalities were evaluated for the ability to predict the histologic diagnosis in horses with clinical signs of laminitis as well as in clinically normal horses and horses that were in a population at risk for developing laminitis. Signal intensity and architectural changes within the corium and laminae were readily seen at 4.7 T, and there was a strong association with the histologic diagnosis of active laminitis. Measurements obtained with MR imaging were more sensitive and specific predictors of laminitis than those obtained radiographically. Subjective evaluation with MR imaging was more sensitive than with radiography and should become more specific with greater understanding of normal anatomy.  相似文献   

16.
Implants containing metallic components have the potential to become heated or move within the patient while in the magnetic resonance (MR) environment. Despite containing a ferromagnetic core and having been in use for over 20 years, no information is available on the safety of veterinary radiofrequency identification devices during MR examinations. These devices are the most commonly encountered metallic implants in dogs and cats undergoing MR imaging. Three commercial veterinary microchips were evaluated for safety in the MR environment at 1 T. Parameters tested were translational force, torque, heating, artifact production, and function. Translation and torque were larger than that expected from normal activity under normal gravity. No significant heating was observed. Signal void artifacts may affect diagnosis if they are too close to the area of clinical importance. Microchip function was unaffected by routine clinical MR imaging. Capsule formation around devices is a major factor in counteracting translation and torque. Our findings support that is acceptable for patients to undergo MR imaging with this 1 T system following an interval of 3 months postimplantation to allow capsule growth. Because of the complex interactions involved, these observations may not be translatable to MR scanners of different field strength and/or manufacturer. Further safety testing of these and other radiofrequency identification devices is therefore recommended at different field strengths and equipment specifications.  相似文献   

17.
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   

18.
Magnetic resonance imaging (MR) was used to make a diagnosis of equine nigropallidal encephalomalacia in a horse. Equine nigropallidal encephalomalacia is a neurodegenerative disease that has many characteristics with Parkinson-like diseases in humans. Historically, horses were euthanized based on clinical signs and exposure to the toxic weed, yellow star thistle (Centaurea solstitialis). Previously, the disease has only been confirmed on necropsy. MR imaging can provide accurate and sensitive visualization of typical lesions seen in the brain of horses affected with equine nigropallidal encephalomalacia. Lesions were seen on T1-weighted, T2-weighted and proton density images. There was no contrast enhancement following Gd-DTPA administration. Lesions seen on MR were confirmed at necropsy. Using MR to confirm a diagnosis of equine nigropallidal encephalomalacia will prevent unnecessary suffering of horses and expense to owners that would otherwise incur, while further diagnostics are performed.  相似文献   

19.
Spinal epidural empyema is defined an accumulation of purulent material in the epidural space of the vertebral canal. Spinal epidural empyema should be considered as a differential diagnosis in dogs with pyrexia, spinal pain, and rapidly progressing myelopathy. Magnetic resonance (MR) imaging is the imaging test of choice in humans. Here, we describe the MR imaging features of five dogs with confirmed spinal epidural empyema. The epidural lesions appeared as high or mixed signal masses in T2-weighted (T2W) images. Increased signal within the spinal cord gray matter at the site of the lesion was detected in T2W images in all dogs. Two patterns of enhancement were detected on postcontrast T1-weighted (T1W) images. Mild to moderate peripheral enhancement was seen in three dogs and a diffuse pattern of enhancement was seen in one. Discospondylitis was identified in three dogs on T1W postcontrast images. Decompressive spinal surgery was performed in all dogs. Bacteria isolated from the abnormal epidural tissue were Enterobacter cloacae, coagulase-positive Staphylococci, Pasteurella multocida, and Escherichia coli. In one dog bacteria were not isolated. These MR imaging features, along with appropriate clinical signs, can allow prompt diagnosis and appropriate treatment planning.  相似文献   

20.
OBJECTIVE: To develop a quantitative method of interpreting tibial scintigrams of Thoroughbred racehorses with tibial stress fractures that may facilitate diagnosis of fractures and to provide prognostic information regarding future performance of affected horses. ANIMALS: 35 Thoroughbred racehorses. PROCEDURES: Static bone-phase scintigrams of tibial stress fractures were quantitatively analyzed by use of ratios of the mean radionuclide counts per pixel in a region of interest (ROI) drawn around the area of increased uptake of radiopharmaceutical to mean counts per pixel in a second ROI drawn around an apparently normal area of the tibial diaphysis. In horses with unilateral fractures, ratios for the contralateral tibia were determined by use of 2 ROIs drawn at the same positions as the ROIs in the fractured tibia. Ratios were compared between fractured versus apparently normal tibias, between horses that returned to racing versus those that did not, and among horses with various grades of lameness. The association between ratios for fractured tibias and intervals between diagnosis and return to racing was also assessed. RESULTS: Mean ratio of ROIs in apparently normal tibias was 1.35 (95% confidence interval [CI], 1.21 to 1.50); that in tibias with stress fractures was 3.55 (95% CI, 2.50 to 4.60). These ratios were significantly different. None of the associations between ratios for fractured tibias and grades of lameness or performance outcomes were significant. CONCLUSIONS AND CLINICAL RELEVANCE: Tibial stress fracture scintigrams can be quantitatively analyzed. A prospective study with a controlled rehabilitation period is necessary to evaluate the possible applications of this method.  相似文献   

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