On the ultrasonic properties of tendon Garcia, Tanya; Hornof, William J.; Insana, Michael F.
Ultrasound in medicine & biology,
12/2003, Letnik:
29, Številka:
12
Journal Article
Recenzirano
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 properties that appears to be related to the spatial organization and type of collagen generated during repair. Variation in echo spectra with insonation angle is a robust indicator of mechanical damage. (E-mail: wjhornof@ucdavis.edu)
To evaluate the efficacy and safety of ultrasonographically guided radiofrequency heat ablation of parathyroid masses in dogs with primary hyperparathyroidism.
Clinical trial.
11 dogs.
In all dogs, ...either 1 or 2 parathyroid masses were evident ultrasonographically. Dogs were anesthetized, and a 20-gauge over-the-needle catheter was directed into the parathyroid mass via ultrasonographic guidance. Radiofrequency heat was applied to the stylet of the catheter until there was sonographically apparent change to the entire parenchyma of the mass. Serum total and ionized calcium and parathyroid hormone concentrations were monitored daily for 5 days after the ablation procedure and again at 1, 2, and 3-month intervals, if possible. Dogs were monitored for adverse effects.
One treatment was required in 6 dogs, 2 treatments were required in 2 dogs, and treatment was unsuccessful in 3 dogs. Serum total and ionized calcium concentrations were within reference ranges within 2 days of the last procedure in all 8 successfully treated dogs. Serum parathyroid hormone concentration was decreased 24 hours after treatment in all 8 dogs. Hypocalcemia developed in 5 of the 8 successfully treated dogs, all of which required treatment. One dog had a transient voice change. Other adverse effects were not reported.
Ultrasonographically guided radiofrequency heat ablation of parathyroid masses is a safe and effective alternative to surgery in dogs with primary hyperparathyroidism.
Objective—To determine efficacy and safety of percutaneous radiofrequency heat ablation for treatment of hyperthyroidism in cats. Design—Prospective study. Animals—9 cats. Procedure—Hyperthyroidism ...was diagnosed via clinical signs and high serum total (TT4) and free thyroxine (fT4) concentrations. One or 2 hyperfunctional cervical thyroid nodules were detected by use of scintigraphy and ultrasonography. If cats had 1 abnormal thyroid lobe, heat ablation was performed on that lobe; if cats had 2 abnormal lobes, heat ablation was applied to the larger lobe. Overall, heat ablation was performed 14 times in the 9 cats. Clinical signs and serum TT4, fT4, and calcium concentrations were monitored daily for 2 days after the procedure, weekly for the first month, and then monthly. Laryngeal function was evaluated and cervical ultrasonography and thyroid scintigraphy were also performed. Monitoring continued for as long as 9 months after heat ablation if a cat became euthyroid or until an owner chose an alternative treatment because of recurrence of hyperthyroidism. Results—Serum TT4 and fT4 concentrations transiently decreased after all 14 heat ablation procedures (≤ reference range after 10 of 14 treatments) within 2 days after the procedure. Cats were euthyroid for 0 to 18 months (mean, 4 months). Hyperthyroidism recurred in all cats. Adverse effects included transient Horner's syndrome (2 cats) and laryngeal paralysis without clinical signs (1 cat). Conclusions and Clinical Relevance—Percutaneous heat ablation as a treatment for hyperthyroidism in cats is effective transiently but not permanently.
To provide a detailed description of the vascular anatomy of the distal portion of the forelimbs of horses by use of computed tomography angiography (CTA).
6 forelimbs of 5 horses and 1 forelimb from ...an equine cadaver; none of the horses had orthopedic or vascular disease.
Horses were anesthetized and CTA was conducted on the dependent forelimb. A catheter was inserted in the median artery, and contrast medium was infused at a rate of 3 mL/s. A computed tomography (CT) scanner was used to obtain contiguous slices from the region of the proximal sesamoid bones to the toe. All horses were allowed to recover from anesthesia. To help identify vessel patterns in the distal portion of the forelimb, the median artery and lateral palmar digital vein of a heparinized forelimb obtained from an equine cadaver were infused with red and blue polymethylmethacrylate and the distal portion of that forelimb was then sectioned to correspond to CTA images.
Vessel patterns in CTA images matched vascular anatomic structures of the cadaver forelimb and were consistent with published anatomic structures. Major and minor vessels were consistently visible in CTA images of all horses. There were no complications reported in any horses.
Use of CTA provided a highly detailed depiction of the vasculature of the distal portion of the equine forelimb. This was a safe technique and should be useful in the evaluation of the blood supply to the distal portion of the forelimb.
Objective— To determine the sensitivity and specificity of radiographic evaluation of radio‐ulnar incongruence in canine elbow joints in vitro.
Study design— Radiographic evaluation of induced ...radio‐ulnar incongruence in canine cadaveric forelimbs by radiologists blinded to study design.
Sample population— Six cadaveric canine left forelimbs.
Methods— Extended lateral, 90° flexed lateral, and cranio‐caudal projections were taken of the elbow joint of six cadaveric canine forelimbs. A four‐pin, type I external skeletal fixator (ESF) with a linear motor side bar was attached to the medial aspect of the radius, and a 2‐cm segment of bone was removed from the mid‐diaphysis. A 3.5‐mm cortical bone screw placed from the medial to lateral styloid processes prevented relative movement between the distal radius and ulna during radial shortening. The ESF was used to progressively shorten the radius in increments of 0.5 mm to a total of 4 mm. The three radiographic projections were repeated after each incremental change of length. After the study, each elbow joint was disarticulated to confirm the presence of a step defect. The original radiographs and three copies were randomized and then evaluated by four radiologists blinded to the study design. Radiologists were asked to evaluate whether the joint was normal or abnormal and if there was evidence of radio‐ulnar incongruence. The ability of each radiologist to correctly identify congruent elbows (specificity) and incongruent elbows (sensitivity) was calculated.
Results— The median specificity was 86% using the lateral projection and 82% using the cranio‐caudal projection. The median sensitivities using the lateral and cranio‐caudal radiographic projections were 78% and 79%, respectively. The degree of radial shortening required for individual radiologists to achieve a sensitivity of 90% ranged from 1.5 mm to greater than 4 mm.
Clinical relevance— Standard radiographic evaluation for radio‐ulnar incongruence in the dog may be associated with relatively poor sensitivity and specificity. Invasive surgical procedures and screening programs that rely on radiographic diagnosis of radio‐ulnar incongruence should be discouraged until a more reliable method of diagnosis of this type of elbow joint incongruence is available.
The ability to make repetitive non‐invasive measurements of gastric emptying of nutritive solids in awake, unstressed mice is highly desirable. The aim of the present study was to develop such a ...technique using nuclear scintigraphy and diets differing in triglyceride content. Awake mice were accustomed to light restraint and to feeding cooked, egg white (0.00 g fat g−1), whole egg (0.10 g fat g−1), or egg yolk (0.31 g fat g−1). Gastric emptying of each diet was measured by labelling the test meals with Technetium99m Mebrofenin and using a conventional gamma camera equipped with a high resolution, parallel hole collimator. Gastric emptying of cooked whole egg was also determined following administration of either vehicle or CCK A receptor antagonist, devazepide. The half‐emptying time (t1/2) significantly increased with increasing triglyceride content from 14 ± 5 min to 51 ± 6 min and 82 ± 4 min for egg white, whole egg and egg yolk, respectively. Administration of devazepide significantly decreased t1/2 of whole egg to 28 ± 2 min. These results demonstrate the sensitivity and predictability of this technique in mice and importantly, provide an opportunity to alter the macronutrient or caloric content of the meal to determine effects on gastric emptying.
To evaluate the efficacy, feasibility, and safety of ultrasound-guided chemical ablation of parathyroid masses in dogs with primary hyperparathyroidism.
Prospective clinical trial.
8 dogs.
In all ...dogs, a solitary parathyroid mass was evident ultrasonographically. Dogs were anesthetized with propofol, and a 27-gauge needle was directed into the parathyroid mass under ultrasound guidance. Ethanol (96%) was injected into the mass until there was evidence of diffusion of fluid throughout the mass. Serum total calcium, ionized calcium, phosphorus, and parathyroid hormone (PTH) concentrations were monitored daily for 5 to 7 days after the ablation procedure and again 1, 3, and 6 months after the procedure. Dogs were also monitored for adverse effects. Follow-up ultrasonography was performed 5 days and 1 month after the ablation procedure.
One injection was required in 7 dogs, and 2 injections were required in 1. Serum total and ionized calcium concentrations were within reference ranges within 24 hours after treatment in 7 dogs and within 5 days in 1 dog. Serum PTH concentration decreased and serum phosphorus concentration increased within 24 hours after treatment in all 8 dogs. Transient hypocalcemia developed in 4 dogs during the first 5 days after treatment, but only 1 dog required treatment for hypocalcemic tetany. Hypercalcemia recurred in 1 dog 1 month after the procedure and surgical removal of the parathyroid mass was required. Other adverse effects were not reported.
Ultrasound-guided chemical ablation of parathyroid masses is a safe and effective alternative to surgery for dogs with primary hyperparathyroidism.
Objective— To describe self‐retaining braces for canine shoulder, elbow, hip, and stifle arthroscopy.
Study Design— Clinical design and application.
Sample Population— Clinical patients admitted for ...elective arthroscopy.
Methods— Self‐retaining braces were designed and constructed from commercially available products, steel tubing, and upholstery. The design efficacy was determined by clinical use.
Results— A shoulder/hip retraction device was constructed from a heavy‐duty Mayo stand and a steel T frame. An elbow brace and a stifle brace were constructed from a commercially available positioning arm and steel tubing. These devices were used successfully in clinical canine arthroscopy and provided consistent stability for arthroscopic surgery without the need of a surgical assistant.
Conclusions— Arthroscopic self‐retaining braces can be constructed from commercially available products and other simple materials to provide reliable patient positioning without the need for a surgical assistant.
Clinical relevance— Self‐retaining braces may provide improved patient stabilization and eliminate the need for a surgical assistant in most cases of canine arthroscopy.
The objective of this work was to compare the accuracy of radiographs and magnetic resonance imaging (MRI) for estimating appendicular osteosarcoma margins. The accuracy of computed tomography (CT) ...and bone scintigraphy was also assessed when these studies were available. Eight dogs with appendicular osteosarcoma underwent radiographic and MRI of affected limbs. In addition, bone scintigraphy was performed in six dogs and CT examination was performed in five dogs. Two observers jointly measured tumor length on all imaging studies. Correlative gross and histologic evaluation of all affected limbs was performed to determine tumor extent as measured from the nearest articular surface. Results from imaging studies were compared to gross and microscopic morphometry findings to determine the accuracy of each modality for determining tumor boundaries. MRI images were accurate with a mean overestimation of actual tumor length of 3 ± 13%. T1‐weighted non‐contrast images were superior in identifying intramedullary tumor margins in most instances whereas contrast‐enhanced images provided supplemental information in two dogs. Lateromedial and craniocaudal radiographs overestimated tumor length by 17 ± 28% and 4 ± 26%, respectively. Scintigraphy and CT overestimated tumor margins by 14 ±. 28% and 27 ±36%, respectively. MRI appears to be an accurate diagnostic imaging modality in determining intramedullary osteosarcoma boundaries. MRI should be considered as part of a pre‐operative assessment of appendicular osteosarcoma, particularly when a limb‐sparing procedure is contemplated.
