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Topic:Diagnostic Technique

Diagnostic techniques in equine medicine encompass a range of procedures and tools used to identify diseases, injuries, or other health conditions in horses. These techniques include imaging methods such as radiography, ultrasonography, and magnetic resonance imaging (MRI), as well as laboratory tests like blood work and tissue biopsies. Each diagnostic method provides specific information that can aid in the assessment and management of equine health issues. Radiography is commonly used for evaluating bone structures, while ultrasonography is useful for soft tissue examination. MRI offers detailed images of both soft and hard tissues, though its use is limited by cost and availability. Laboratory tests can detect biochemical and hematological changes indicative of disease. This page compiles peer-reviewed research studies and scholarly articles that explore the development, application, and efficacy of various diagnostic techniques in equine veterinary practice.
Evaluation of serum concentrations of biomarkers of skeletal metabolism and results of radiography as indicators of severity of osteochondrosis in foals.
American journal of veterinary research    February 21, 2004   Volume 65, Issue 2 143-150 doi: 10.2460/ajvr.2004.65.143
Billinghurst RC, Brama PA, van Weeren PR, Knowlton MS, McIlwraith CW.To determine whether serum concentrations of biomarkers of skeletal metabolism can, in conjunction with radiographic evaluation, indicate severity of osteochondrosis in developing horses. Methods: 43 Dutch Warmblood foals with varying severity of osteochondrosis. Methods: 24 foals were monitored for 5 months and 19 foals were monitored for 11 months. Monthly radiographs of femoropatellar-femorotibial and tibio-tarsal joints were graded for osteochondral abnormalities. Serial blood samples were assayed for 8 cartilage and bone biomarkers. At the end of the monitoring period, foals were examined...
Electromyographic activity of the longissimus dorsi muscles in horses during trotting on a treadmill.
American journal of veterinary research    February 21, 2004   Volume 65, Issue 2 155-158 doi: 10.2460/ajvr.2004.65.155
Licka TF, Peham C, Frey A.To use electromyography (EMG) to measure physiologic activity of the longissimus dorsi muscles of horses during trotting on a treadmill. Methods: 15 adult horses (5 to 20 years old that weighed 450 to 700 kg) that did not have clinical signs of back pain. Methods: Data were recorded for each horse during trotting on a treadmill at speeds of 2.6 to 4.4 m/s. Surface electromyography was recorded bilaterally from the longissimus dorsi muscles at the levels of T12, T16, and L3. Results: In each motion cycle, 2 EMG maxima were found at the end of the diagonal stance phases. The EMG activity peaked ...
Structure of peripheral cementum of normal equine cheek teeth.
Journal of veterinary dentistry    February 21, 2004   Volume 20, Issue 4 199-208 doi: 10.1177/089875640302000401
Mitchell SR, Kempson SA, Dixon PM.The structure of peripheral cementum of mandibular and maxillary cheek teeth was studied by gross observation, light microscopy, and scanning and transmission electron microscopy. Teeth from four horses aged 4, 8, 17, and 30-years-old were examined. The cementum of the occlusal surface was thicker on the buccal aspect when compared with the lingual aspect of mandibular teeth. The cementum of the occlusal surface was thicker on the palatal aspect when compared with the buccal aspect of maxillary teeth. There was no peripheral cementum on the interdental aspects of either mandibular or maxillary...
Effects of extracorporeal shock wave therapy and radial pressure wave therapy on elasticity and microstructure of equine cortical bone.
American journal of veterinary research    February 21, 2004   Volume 65, Issue 2 207-212 doi: 10.2460/ajvr.2004.65.207
Pauwels FE, McClure SR, Amin V, Van Sickle D, Evans RB.To measure changes in the modulus of elasticity (E) and describe histologic findings after extracorporeal shock wave therapy and radial pressure wave therapy on equine cortical bone specimens. Methods: 16 bone specimens from the proximodorsal cortex of an equine third metacarpal or metatarsal bone. Methods: Baseline E was determined by the density (p) and unidirectional ultrasound transmission velocity (C) of each specimen according to the equation E = pC2. Eight specimens were treated with 500 pulses of 0.15 mJ/mm2 of extracorporeal shock wave therapy, and 8 specimens were treated with 500 pu...
Detection of equine herpesvirus 3 in equine skin lesions by polymerase chain reaction. Kleiboeker SB, Chapman RK.During a recent breeding season, ulcerative, pustular skin lesions were observed on the external genitalia of 2 mares and 1 stallion within a small herd. Based on the location and description of the skin lesions plus the clinical history, equine coital exanthema, caused by equine herpesvirus 3 (EHV3), was the primary differential diagnosis. Scrapings of skin lesions from the perineum of 2 mares were submitted for diagnostic evaluation. Virus isolation was attempted by inoculation of several cell lines of equine origin, but no cytopathic agent was detected. The skin scrapings were processed for...
Diagnosis of West Nile virus infection in horses. Kleiboeker SB, Loiacono CM, Rottinghaus A, Pue HL, Johnson GC.The North American West Nile virus (WNV) epizootic, which began in 1999, has caused significant morbidity and mortality in horses. Because experimental infection has failed to consistently produce encephalitis in inoculated horses, investigation of naturally occurring cases was used to optimize strategies for diagnosis of this disease. Although WNV RNA could be detected by reverse transcriptase-polymerase chain reaction (RT-PCR) performed on whole blood collected from both clinically affected horses and unaffected herdmates, the diagnostic sensitivity of this approach was low compared with IgM...
Detection and quantification of cocaine metabolites in urine samples from horses administered cocaine.
Journal of veterinary pharmacology and therapeutics    February 14, 2004   Volume 26, Issue 6 429-434 doi: 10.1046/j.0140-7783.2003.00535.x
Kollias-Baker C, Maxwell L, Stanley S, Boone T.Cocaine is a naturally occurring alkaloid that is commonly abused by human-beings for its psychostimulatory effects. Occasionally, very small concentrations (i.e. <100 ng/mL) of the primary cocaine metabolite, benzoylecgonine (BZE) have been detected in urine collected from horses competing in athletic events. In this study urine samples, collected from four horses following the administration of 2.5 and 20 mg of cocaine sublingually and 50 mg of cocaine intravenously, were analyzed for the presence of cocaine and/or its metabolites by enzyme-linked immunosorbent assay (ELISA) and gas chrom...
A possible role for the covalent heme-protein linkage in cytochrome c revealed via comparison of N-acetylmicroperoxidase-8 and a synthetic, monohistidine-coordinated heme peptide.
Biochemistry    February 11, 2004   Volume 43, Issue 6 1656-1666 doi: 10.1021/bi035531p
Cowley AB, Lukat-Rodgers GS, Rodgers KR, Benson DR.N-Acetylmicroperoxidase-8 (1) contains heme and residues 14-21 of horse mitochondrial cytochrome c (cyt c). The two thioether bonds linking protein to heme in cyt c are present in 1, and the native axial ligand His-18 remains coordinated to iron. As an approach to probing structural or functional roles played by the double covalent heme-protein linkage in cyt c, we have initiated a study in which the properties of 1 are compared with those of a synthetic mono-His coordinated heme peptide containing a single covalent linkage (2). One consequence of the greater conformational restriction imposed...
Genetic characterization of equine arteritis virus during persistent infection of stallions.
The Journal of general virology    February 11, 2004   Volume 85, Issue Pt 2 379-390 doi: 10.1099/vir.0.19545-0
Balasuriya UBR, Hedges JF, Smalley VL, Navarrette A, McCollum WH, Timoney PJ, Snijder EJ, MacLachlan NJ.Equine arteritis virus (EAV) causes a persistent infection of the reproductive tract of carrier stallions. The authors determined the complete genome sequences of viruses (CW96 and CW01) that were present 5 years apart in the semen of a carrier stallion (CW). The CW96 and CW01 viruses respectively had only 85.6 % and 85.7 % nucleotide identity to the published sequence of EAV (EAV030). The CW96 and CW01 viruses had two 1 nt insertions and a single 1 nt deletion in the leader sequence, and a 3 nt coding insertion in ORF1a; thus their genomes included 12 708 nt as compared to the 12 704 nt in EA...
Comparison of sensitivities of virus isolation, antigen detection, and nucleic acid amplification for detection of equine influenza virus.
Journal of clinical microbiology    February 10, 2004   Volume 42, Issue 2 759-763 doi: 10.1128/JCM.42.2.759-763.2004
Quinlivan M, Cullinane A, Nelly M, Van Maanen K, Heldens J, Arkins S.Four seronegative foals aged 6 to 7 months were exposed to an aerosol of influenza strain A/Equi/2/Kildare/89 at 10(6) 50% egg infective doses (EID(50))/ml. Nasopharyngeal swabs were collected for 10 consecutive days after challenge. Virus isolation was performed in embryonated eggs, and the EID(50) was determined for all positive samples. The 50% tissue culture infective dose was determined using Madin-Darby canine kidney (MDCK) cells. Samples were also tested by an in vitro enzyme immunoassay test, Directigen Flu A, and by reverse transcription-PCR (RT-PCR) using nested primers from the nucl...
Treatment of suckling beef cattle with a progestagen sponge and oestradiol benzoate or equine chorionic gonadotrophin.
The Veterinary record    February 10, 2004   Volume 154, Issue 4 106-109 doi: 10.1136/vr.154.4.106
Viñoles C, Quintans G, Paiva N, Cavestany D.The ovarian responses of anoestrus beef cows to a combined treatment with medroxy-progesterone acetate (MAP) sponges and oestradiol benzoate or equine chorionic gonadotrophin (eCG) were evaluated. Forty-five suckling Hereford cows were allocated to three equal groups. Group 1 received a MAP sponge for seven days plus an injection of 2 mg oestradiol benzoate when the sponge was inserted (day 0) and 1 mg when the sponge was withdrawn; group 2 received identical treatment until day 7, when a dose of 400 iu of eCG was administered, and group 3 were left untreated as control animals. From day 0 to ...
Evaluation of decision criteria for detection of spinal cord compression based on cervical myelography in horses: 38 cases (1981-2001).
Equine veterinary journal    February 6, 2004   Volume 36, Issue 1 14-20 doi: 10.2746/0425164044864642
van Biervliet J, Scrivani PV, Divers TJ, Erb HN, de Lahunta A, Nixon A.Different criteria have been described based on height reduction of the total myelographic contrast column and components of it as tests for compression of the spinal cord due to cervical stenotic myelopathy (CSM). Fifty percent height reduction of the dorsal myelographic column (DMC), <2 mm empiric height of the DMC and a 40% reduction of the ratio of stenosis calculated based on the height reduction of the entire dural diameter (DD) have been described as decision criteria for considering the test result positive. The reasons for selecting these decision criteria or their accuracies have ...
Transcranial magnetic stimulation: normal values of magnetic motor evoked potentials in 84 normal horses and influence of height, weight, age and sex.
Equine veterinary journal    February 6, 2004   Volume 36, Issue 1 51-57 doi: 10.2746/0425164044864660
Nollet H, Deprez P, van Ham L, Dewulf J, Decleir A, Vanderstraeten G.Cervical spinal cord dysfunction is a common problem in equine medicine and the currently available tests give no objective information about the functionality of the nervous tracts. Therefore, transcranial magnetic stimulation (TMS) was performed in 84 healthy horses of different height in order to have an objective measure for the integrity of the descending motor tracts in normal horses. Objective: To obtain reference values for onset latency and peak-to-peak amplitude of magnetic motor evoked potentials (MMEPs) and to evaluate the possible effect of height, age and gender on the neurophysi...
Measurement of respiratory function by impulse oscillometry in horses.
Equine veterinary journal    February 6, 2004   Volume 36, Issue 1 21-28 doi: 10.2746/0425164044864714
van Erck E, Votion D, Art T, Lekeux P.Due to technical implementations and lack of sensitivity, pulmonary function tests are seldom used in clinical practice. Impulse oscillometry (IOS) could represent an alternative method. Objective: To define feasibility, methodology and repeatability of IOS, a forced oscillation technique that measures respiratory resistance (Rrs) and reactance (Xrs) from 5 to 35 Hz during spontaneous breathing, in horses. Methods: Using 38 healthy horses, Rrs and Xrs reference values were defined and influence of individual biometrical parameters was investigated. In addition, IOS measurements of 6 horses sho...
Color Doppler ultrasound evaluation of testicular blood flow in stallions.
Theriogenology    February 6, 2004   Volume 61, Issue 5 799-810 doi: 10.1016/s0093-691x(03)00227-9
Pozor MA, McDonnell SM.The objectives of this study were to evaluate the potential use of color Doppler ultrasound to characterize blood flow to the stallion testis, and to establish reference values for Doppler measures of blood flow in the testicular artery of the stallion. Both testes from each of 52 horses were examined using a pulsed-wave color Doppler ultrasound with a sector array 5/7.5 MHz transducer with a 1mm gate setting. Peak systolic velocity (PSV), end diastolic velocity (EDV), resistive index (RI), and pulsatility index (PI) of the testicular artery were measured in each of two locations, the convolut...
Prevalence of parasite eggs (Strongyloides westeri, Parascaris equorum, and strongyles) and oocysts (Emeria leuckarti) in the feces of Thoroughbred foals on 14 farms in central Kentucky in 2003.
Parasitology research    February 4, 2004   Volume 92, Issue 5 400-404 doi: 10.1007/s00436-003-1068-2
Lyons ET, Tolliver SC.Prevalence of internal parasites was determined by fecal examination for eggs and oocysts in Thoroughbred foals in central Kentucky in 2003. Fecal samples were examined from 733 foals on 14 farms. This included 70 trips to the farms and a total of 2,346 fecal samplings. Monthly collection of fecal samples was begun for four farms in February, six in March, three in April, and one farm in May. Termination of the study for all farms was the end of July. A criterion was that the foals be at least 10 days old for initial samplings. If available, the same foals were sampled each time, in addition t...
Serum osteocalcin in donkeys as evaluated with an equine-specific radioimmunoassay.
Journal of animal physiology and animal nutrition    February 1, 2004   Volume 88, Issue 1-2 1-6 doi: 10.1111/j.1439-0396.2004.00443.x
Carstanjen B, Amory H, Youssao I, Remy B.The purpose of this study was to validate an equine-specific osteocalcin (OC) radioimmunoassay (RIA) for use in donkeys and to establish age-related changes in serum OC concentrations in healthy donkeys. Serial dilutions of donkey serum showed parallelism with standard curves obtained with the equine-specific OC RIA. There was a tight linear regression between donkey serum OC values obtained with the equine specific OC RIA and a commercially available bovine-specific OC RIA. Serum OC levels of 27 healthy donkeys, analysed with the equine-specific OC RIA, showed a tight negative logarithmic reg...
Management of comminuted fractures of the proximal phalanx in horses: 64 cases (1983-2001).
Journal of the American Veterinary Medical Association    January 23, 2004   Volume 224, Issue 2 254-263 doi: 10.2460/javma.2004.224.254
Kraus BM, Richardson DW, Nunamaker DM, Ross MW.To report the outcome of surgical treatment of comminuted fractures of the proximal phalanx in horses. Methods: Retrospective study. Methods: 64 horses. Methods: Medical records and radiographs were reviewed to obtain information regarding signalment, fracture classification, and treatment. Follow-up information was obtained by telephone conversation or evaluation of production records. Results: Thirty-eight horses had moderately comminuted fractures of the proximal phalanx. Two horses were euthanatized immediately. Fractures of the proximal phalanx in 36 horses were repaired with open reducti...
Exostoses of the caudal perimeter of the radial physis as a cause of carpal synovial sheath tenosynovitis and lameness in horses: 10 cases (1999-2003).
Journal of the American Veterinary Medical Association    January 23, 2004   Volume 224, Issue 2 264-270 doi: 10.2460/javma.2004.224.264
Nixon AJ, Schachter BL, Pool RR.To determine the clinical, radiographic, ultrasonographic, and arthroscopic findings associated with tenosynovitis of the carpal synovial sheath induced by exostoses that originate from the caudal surface of the physeal scar of the distal radius and determine the results of surgical removal of those exostoses in horses. Methods: Retrospective study. Methods: 10 horses. Methods: Medical records of horses with effusion in the carpal synovial sheath and lameness evaluated from 1999 to 2003 were examined. Results: All horses had a history of intermittent mild to moderate effusion of the carpal syn...
Evaluation of urine sucrose concentration for detection of gastric ulcers in horses.
American journal of veterinary research    January 15, 2004   Volume 65, Issue 1 31-39 doi: 10.2460/ajvr.2004.65.31
O'Conner MS, Steiner JM, Roussel AJ, Williams DA, Meddings JB, Pipers F, Cohen ND.To evaluate the use of sucrose permeability testing to detect ulcers in the gastric squamous mucosa of horses. Methods: 13 adult horses ranging from 5 to 19 years of age. Methods: Following induction of gastric ulcers by intermittent feed deprivation, horses underwent sucrose permeability testing (administration of sucrose by nasogastric intubation followed by collection of urine at 2 and 4 hours after intubation) and gastric endoscopy. Squamous ulcers were assigned a severity score (range, 0 to 3) by use of an established scoring system. Horses were subsequently administered omeprazole for 21...
Nucleotide sequence of equine erythropoietin and characterization of region-specific antibodies.
American journal of veterinary research    January 15, 2004   Volume 65, Issue 1 15-19 doi: 10.2460/ajvr.2004.65.15
Sato F, Yamashita S, Kugo T, Hasegawa T, Mitsui I, Kijima-Suda I.To determine the full-length complementary DNA (cDNA) sequence of equine erythropoietin (EPO) and to develop region-specific antibodies to differentiate equine EPO (eEPO) and human EPO (hEPO). Methods: RNA and lysate extracted from renal tissues of an adult Thoroughbred. Methods: Full-length cDNA was determined by use of a reverse transcriptase-polymerase chain reaction assay and a rapid amplification of cDNA ends method. The deduced amino acid sequence was compared with sequences of EPO reported for other species. Furthermore, 4 synthetic peptides were designed in 2 distinctive parts of the e...
Evaluation of plasma carboxy-terminal cross-linking telopeptide of type I collagen concentration in horses.
American journal of veterinary research    January 15, 2004   Volume 65, Issue 1 104-109 doi: 10.2460/ajvr.2004.65.104
Carstanjen B, Hoyle NR, Gabriel A, Hars O, Sandersen C, Amory H, Remy B.To evaluate a human assay for quantification of carboxy-terminal cross-linking telopeptide of type I collagen (CTX-I), assess the influence of age on plasma CTX-I concentration, investigate the relationship between plasma CTX-I and serum osteocalcin concentrations, and determine whether concentrations of plasma CTX-I or serum osteocalcin fluctuate in circadian manner in horses. HORSES: 75 clinically normal horses. Methods: Cross-reactivity between equine serum CTX-I and CTX-I antibodies in an automated electrochemiluminescent sandwich antibody assay (ECLIA) was evaluated via a specificity test...
Molecular cloning of a Babesia caballi gene encoding the 134-kilodalton protein and evaluation of its diagnostic potential in an enzyme-linked immunosorbent assay.
Clinical and diagnostic laboratory immunology    January 13, 2004   Volume 11, Issue 1 211-215 doi: 10.1128/cdli.11.1.211-215.2004
Tamaki Y, Hirata H, Takabatake N, Bork S, Yokoyama N, Xuan X, Fujisaki K, Igarashi I.A Babesia caballi gene encoding the 134-kDa (BC134) protein was immunoscreened with B. caballi-infected horse serum. An enzyme-linked immunosorbent assay (ELISA) using recombinant BC134 protein could effectively differentiate B. caballi-infected horse sera from Babesia equi-infected or noninfected control horse sera. These results suggest that the recombinant BC134 protein is a potential diagnostic antigen in the detection of B. caballi infection.
Development of an immunochromatographic test with recombinant EMA-2 for the rapid detection of antibodies against Babesia equi in horses.
Journal of clinical microbiology    January 13, 2004   Volume 42, Issue 1 359-361 doi: 10.1128/JCM.42.1.359-361.2004
Huang X, Xuan X, Xu L, Zhang S, Yokoyama N, Suzuki N, Igarashi I.An immunochromatographic test (BeICT) for the rapid detection of antibodies against Babesia equi was developed. It clearly differentiated B. equi-infected horses from B. caballi-infected and uninfected horses. The agreement with enzyme-linked immunosorbent assay results was 96.7% in the detection of field sera. The results suggest that BeICT is rapid, simple, reliable, and suitable for use to detect B. equi infection in the field.
Characterisation of IgG(T) serum antibody responses to two larval antigen complexes in horses naturally- or experimentally-infected with cyathostomins.
International journal for parasitology    January 9, 2004   Volume 34, Issue 1 101-108 doi: 10.1016/j.ijpara.2003.09.008
Dowdall SM, Proudman CJ, Klei TR, Mair T, Matthews JB.Cyathostomins are the most common parasitic nematodes of horses. Larval stages, which inhabit the intestinal wall, are particularly pathogenic and can cause severe colitis and colic. Despite their clinical importance, diagnostic techniques for the prepatent stages do not exist. A method that could estimate mucosal infection intensity would have a major impact on the control and diagnosis of cyathostominosis. Here, serum IgG(T) responses to two larval antigen complexes of 25 and 20 kDa were quantified in horses with experimental infections, natural infections and in horses that presented with c...
Scintigraphic abnormalities of the pelvic region in horses examined because of lameness or poor performance: 128 cases (1993-2000).
Journal of the American Veterinary Medical Association    January 9, 2004   Volume 224, Issue 1 88-95 doi: 10.2460/javma.2004.224.88
Davenport-Goodall CL, Ross MW.To identify scintigraphic abnormalities in the pelvic region of horses examined because of hind limb lameness or poor performance and determine the clinical relevance of areas of abnormal radiopharmaceutical uptake (ARU) in these horses. Methods: Retrospective study. Methods: 128 horses. Methods: Medical records were reviewed, and information on signalment, history, admitting complaints, physical examination findings, and results of lameness examinations was recorded. Clinical relevance of areas of ARU was determined by comparison with results of other diagnostic tests. For horses with clinica...
Dual photon absorptiometry using a gadolinium-153 source applied to measure equine bone mineral content.
Physics in medicine and biology    January 2, 2004   Volume 48, Issue 23 3851-3863 doi: 10.1088/0031-9155/48/23/004
Moure A, Reichmann P, Gamba HR.The application of the dual photon absorptiometry (DPA) technique, using gadolinium-153 as the photon source, to evaluate the bone mineral density (BMD) of the third metacarpal bone of horses is presented. The radiation detector was implemented with a NaI(TI) scintillator coupled to a 14 stage photomultiplier. A modular mechanical system allows the position of the prototype to be adjusted in relation to the animal. A moveable carrier makes it possible to scan the third metacarpal with a velocity adjustable between 1 and 12 mm s(-1), in steps of 1 mm s(-1), for a total distance of 250 mm. The p...
Scintigraphy of the sacroiliac joint region in asymptomatic riding horses: scintigraphic appearance and evaluation of method. Erichsen C, Eksell P, Widström C, Berger M, Holm KR, Johnston C.The sacroiliac region in 33 clinically normal riding horses was examined with scintigraphy to determine the normal scintigraphic appearance, to evaluate a semiquantitative method used to calculate a sacroiliac joint (SI joint) ratio, and to identify factors that affect the scintigraphic appearance of the pelvis. The scintigraphic examination included dorsal views of each SI joint region and one lateral view of the urinary bladder. Two predefined areas (the SI joint and the area between the tuber sacrale and the SI joint) were evaluated subjectively by comparing the intensity in each area to th...
Effect of trabecular orientation on mechanical resistance and ultrasound propagation in specimens of equine vertebrae.
Ultrasound in medicine & biology    December 31, 2003   Volume 29, Issue 12 1777-1785 doi: 10.1016/j.ultrasmedbio.2003.08.003
Cavani F, Fini M, de Terlizzi F, Cadossi M, Ciminelli L, Ortolani S, Cherubini R, De Aloysio D, Giavaresi G, Cadossi R, Canè V.Osteoporosis involves alterations, not only in density, but also in the architectural organisation of the bone; in particular, trabecular orientation, following the skeletal load directions, lends a high degree of stiffness to the whole bone. We investigated the relationship between trabecular orientation, density, stiffness and ultrasound (US) propagation in two orthogonal directions (par. = parallel to, and ort. = orthogonal to the main orientation of the trabeculae) in cylindrical equine bone specimens (thoracic vertebrae) where a preferential orientation is present. A total of 15 cylinders...
On the ultrasonic properties of tendon.
Ultrasound in medicine & biology    December 31, 2003   Volume 29, Issue 12 1787-1797 doi: 10.1016/s0301-5629(03)01069-x
Garcia T, Hornof WJ, Insana MF.The strong dependence of tendon echogenicity on insonation angle is explored by analyzing echo spectra. Combining echo spectra with high-resolution images from several modalities reveals that fluid spaces surrounding fascicles and bundles are likely sources of ultrasonic scatter. Mathematical models of tendon structure are proposed to explain how the anisotropic microstructure of tendon gives rise to angle-dependent echogenicity. Echo spectra from spontaneously damaged equine tendon samples were compared with normal equine tendon and found to exhibit a dramatic decrease in anisotropic properti...