A SURVEY OF RADIOLOGISTS AND REFERRING VETERINARIANS REGARDING IMAGING REPORTS

An imaging report is a vital communication tool between a radiologist and clinician. In a field where in‐person communication may not be readily available, it is imperative that the report clearly relays pertinent clinical information in a timely manner. The purpose of this observational study was to describe and compare opinions and expectations of small animal general practitioners, veterinary specialists, and veterinary radiologists regarding the imaging report. Online surveys were distributed, and data were collected from 202 veterinary clinicians and 123 veterinary radiologists. The majority (89%) of clinicians were satisfied with their imaging reports and stated that they read the radiology report as soon as it was available (92%). Just less than half (48%) of clinicians indicated it was standard of care that a board‐certified veterinary radiologist read all imaging studies. Radiologists and clinicians agreed that a clinical history (98% and 94%, respectively) and clinical question (82% and 68%, respectively) were needed to generate a good radiology report. Fifty‐five percent to 70% of clinicians prefer red bulleted reports, which included incidental findings (96%); while radiologists slightly favored prose reporting (37–46%). Clinicians found it helpful when additional imaging (86%), medical (71%), and surgical recommendations (73%) were made. About one‐third of specialists who had been in practice for >11 years thought they were better able to interpret imaging for their own specialty than the radiologist. Clinicians voiced discontentment with reports that were not completed in a timely manner or did not give a prioritized differential list. Further studies are warranted to provide a more in‐depth evaluation of veterinary radiology reporting structure and style.     

A COMPUTERIZED WORD-BASED DATA SYSTEM FOR A VETERINARY RADIOLOGY DEPARTMENT

Computer programs were developed to record and retrieve the diagnostic findings of a veterinary radiology department. The concluding statements of reports are abstracted into a data file. Records may be retrieved by the computer after selecting any of the following: owner's name, patient number, date, species, breed, sex, age, state of residence, imaging type and diagnosis (word or statement). Also, information retrieved from the hospital financial records (procedures performed) and medical record databases may be combined with imaging report information to provide a powerful tool for clinical research and teaching.     

THE LITERATURE OF VETERINARY IMAGING: THE ANALYSIS OF A QUESTIONNAIRE

250 veterinarians, including 143(57.7%) non-radiologists, replied to a questionnaire on current literature of veterinary imaging. Veterinary Readiology & Ultrasound was considered the best overall journal, being chosen as first choice by 51.6% respondents. It was also judged to have the best photographic reproduction. No book was chosen as first choice by more than 18.4%. Three, Textbook of Diagnostic Radiology, Thrall; Diagnostic Radiology of the Dog & Cat, Kealy and Thoracic Radiography of the Dog & Cat, Suter & Lord, were chosen by 18.4%, 16.8% and 13.2% respondents respectively. Clinically orientated papers and review articles were the preferred contents of journlas. Experience of colleagues and journals were adjudged the best source of information on diagnostic imaging. Differences in results between radiologists and non-radiologists were not great and geographic differences were few. Of the 112 respondents who had published papers on veterinary imaging, 30 (26.4%) were non-radiologists.     

DIAGNOSTIC SENSITIVITY OF ULTRASOUND,RADIOGRAPHY AND COMPUTED TOMOGRAPHY FOR GENDER DETERMINATION IN FOUR SPECIES OF LIZARDS

Gender determination is frequently requested by reptile breeders, especially for species with poor or absent sexual dimorphism. The aims of the current study were to describe techniques and diagnostic sensitivities of ultrasound, radiography, and computed tomography for gender determination (identification of hemipenes) in four species of lizards. Nineteen lizards of known sex, belonging to four different species (Pogona vitticeps, Uromastyx aegyptia, Tiliqua scincoides, Gerrhosaurus major) were prospectively enrolled. With informed owner consent, ultrasound, noncontrast CT, contrast radiography, and contrast CT (with contrast medium administered into the cloaca) were performed in conscious animals. Imaging studies were reviewed by three different operators, each unaware of the gender of the animals and of the results of the other techniques. The lizard was classified as a male when hemipenes were identified. Nineteen lizards were included in the study, 10 females and nine males. The hemipenes were seen on ultrasound in only two male lizards, and appeared as oval hypoechoic structures. Radiographically, hemipenes filled with contrast medium appeared as spindle‐shaped opacities. Noncontrast CT identified hemipenes in only two lizards, and these appeared as spindle‐shaped kinked structures with hyperattenuating content consistent with smegma. Hemipenes were correctly identified in all nine males using contrast CT (accuracy of 100%). Accuracy of contrast radiography was excellent (94.7%). Accuracy of ultrasound and of noncontrast CT was poor (64.3% and 63.1%, respectively). Findings from the current study supported the use of contrast CT or contrast radiography for gender determination in lizards.     

CONTRAST ENHANCEMENT IN MAGNETIC RESONANCE IMAGING USING INTRAVENOUS PARAMAGNETIC CONTRAST MEDIA: A REVIEW

Interest in magnetic resonance (MR) imaging as a major diagnostic tool in veterinary clinical medicine is increasing. Most MR studies are performed with the use of contrast enhancement via intravenous injection of paramagnetic gadolinium-containing contrast media. A vast number of publications are available regarding the use of contrast media in humans. The purpose of this paper is to assist practicing veterinary radiologists in understanding mechanisms of MR contrast enhancement. This paper reviews certain aspects of MR contrast enhancement, including physical, chemical and biologic characteristics of most common MR contrast media targeted primarily at the central nervous system (CNS). Authors also describe processes that explain changes in signal intensity on the MR images.     

USE OF A NOVEL BOARD GAME IN A CLINICAL ROTATION FOR LEARNING THORACIC DIFFERENTIAL DIAGNOSES IN VETERINARY MEDICAL IMAGING

When confronted with various findings on thoracic radiographs, fourth‐year veterinary students often have difficulty generating appropriate lists of differential diagnoses. The purpose of this one‐group, pretest, posttest experimental study was to determine if a game could be used as an adjunct teaching method to improve students’ understanding of connections between imaging findings and differential diagnoses. A novel board game focusing on differential diagnoses in thoracic radiography was developed. One hundred fourth‐year veterinary students took a brief pretest, played the board game, and took a brief posttest as a part of their respective clinical radiology rotations. Pretest results were compared to posttest results using a paired t‐test to determine if playing the game impacted student understanding. Students’ mean scores on the posttest were significantly higher than mean pretest scores (P < 0.0001). Thus, results indicate that playing the board game resulted in improved short‐term understanding of thoracic differential diagnoses by fourth‐year students, and use of the board game on a clinical rotation seems to be a beneficial part of the learning process.     

MAGNETIC RESONANCE IMAGING—A GENERAL OVERVIEW OF PRINCIPLES AND EXAMPLES IN VETERINARY NEURODIAGNOSIS

Magnetic resonance imaging (MRI), a noninvasive technique that provides accurate, detailed, anatomic images, has had a major impact in the diagnosis of human disease. This technique is based upon the inherent magnetic properties of certain nuclei. Induction of the nuclei into a low energy state is achieved by placing them in a static magnetic field. The nuclei may then be excited into a high energy state by application of a radio frequency pulse. When the second field is stopped, the nuclei return to ground state and emit the absorbed energy in the form of a radio signal. This signal is received by a coil that generally surrounds the specimen and converted to an anatomic image through a process of computer-assisted reconstruction. Contrast is altered by applying the second pulse in different sequences (saturation recovery, inversion recovery, and spin echo) and using enhancing agents such as gadolinium. In this paper, we present an overview of the general principles of MRI and some clinical examples in dogs and cats with central nervous system disease.     

INVITED REVIEW: STUDY DESIGN CONSIDERATIONS FOR CLINICAL RESEARCH IN VETERINARY RADIOLOGY AND RADIATION ONCOLOGY

High quality clinical research is essential for advancing knowledge in the areas of veterinary radiology and radiation oncology. Types of clinical research studies may include experimental studies, method‐comparison studies, and patient‐based studies. Experimental studies explore issues relative to pathophysiology, patient safety, and treatment efficacy. Method‐comparison studies evaluate agreement between techniques or between observers. Patient‐based studies investigate naturally acquired disease and focus on questions asked in clinical practice that relate to individuals or populations (e.g., risk, accuracy, or prognosis). Careful preplanning and study design are essential in order to achieve valid results. A key point to planning studies is ensuring that the design is tailored to the study objectives. Good design includes a comprehensive literature review, asking suitable questions, selecting the proper sample population, collecting the appropriate data, performing the correct statistical analyses, and drawing conclusions supported by the available evidence. Most study designs are classified by whether they are experimental or observational, longitudinal or cross‐sectional, and prospective or retrospective. Additional features (e.g., controlled, randomized, or blinded) may be described that address bias. Two related challenging aspects of study design are defining an important research question and selecting an appropriate sample population. The sample population should represent the target population as much as possible. Furthermore, when comparing groups, it is important that the groups are as alike to each other as possible except for the variables of interest. Medical images are well suited for clinical research because imaging signs are categorical or numerical variables that might be predictors or outcomes of diseases or treatments.     

STUDENT PERFORMANCE AND COURSE EVALUATIONS BEFORE AND AFTER USE OF THE CLASSROOM PERFORMANCE SYSTEM™ IN A THIRD‐YEAR VETERINARY RADIOLOGY COURSE

Effective teaching of veterinary radiology can be challenging in a traditional classroom environment. Audience response systems, colloquially known as “clickers,” provide a means of encouraging student interaction. The purpose of this study was to compare student performance and course evaluations before and after using the Classroom Performance System? in the third‐year (fifth semester) didactic radiology course at the University of Tennessee College of Veterinary Medicine. Overall student performance was assessed by comparing median numeric final course grades (%) between years without and with use of the Classroom Performance System?. Grades of students were determined for individual instructors’ sections. Student evaluations of the radiology course were compared for the years available (2007–2010). Student interactions were also evaluated subjectively by instructors who used the Classroom Performance System?. There was a significant difference (p = 0.009) between the median student grade before (2005 – 2008, median 82.2%; interquartile range 77.6–85.7%; range 61.9–95.5%) and after use of the classroom performance system (2009–2010, median 83.6%; interquartile range 79.9–87.9%; range 68.2–93.2%). There was no statistically significant difference in median student grades for individual instructors over the study period. The radiology course student evaluation scores were significantly higher in years where the Classroom Performance System? was used in comparison to previous years (P = 0.019). Subjectively, students appeared more involved when using clickers. Findings indicated that the Classroom Performance System? may be a useful tool for enhancing veterinary radiology education.     

COMPARATIVE EVALUATION OF AN ULTRAVIOLET AND AN ORTHOCHROMATIC RARE-EARTH IMAGING SYSTEM FOR VETERINARY RADIOGRAPHY

The relative quality and speed of a new ultraviolet-emitting screen, ultraviolet-sensitive film rare-earth system (DuPont Ultra-Vision®) was compared to an orthochromatic rare-earth system (Kodak Lanex®) in a clinical trial. Seven different sets of radiographs of a human foot phantom, or actual canine anatomical structures (tarsus, pelvis, skull, chest, abdomen) were evaluated independently by radiologists, radiology residents and technicians who were unaware of the screen/film combinations used. The 400-speed, Ultra-Vision® Rapid/UVG screen/film combination produced supervisor image detail compared to blue/green emitting 400 and 200-speed screen/film combinations. The image detail of the Ultra-Vision® Rapid/UVG system was nearly equivalent to that produced using a 100-speed, fine-detail blue/green emitting screen/film combination. A 200-speed Ultra-Vision® system was also tested and produced thoracic and abdominal radiographs of equivalent to slightly supervisor quality than those produced using blue/green emitting system.     

TISSUE HARMONIC ULTRASOUND FOR IMAGING NORMAL ABDOMINAL ORGANS IN DOGS AND CATS

Normal cats (n = 38) and dogs (n = 40) were imaged with fundamental ultrasound and tissue harmonic ultrasound. Images of the liver, gall bladder, spleen, left kidney, urinary bladder, and jejunum were collected in all animals. Images of the left adrenal gland were collected in all dogs. All normal cats and dogs had improved imaging with tissue harmonic ultrasound. The number of organs with improved conspicuity ranged from one to all organs imaged. The most common organ to have improved conspicuity was the jejunum (100% of dogs and 89% of cats). Significant improvement by tissue harmonic ultrasound was seen in images of gall bladder (p = .05) and left adrenal gland (p = .02) in dogs, and spleen, urinary bladder, and intestinal images (p = .01) in cats. Significant improvement was seen in tissue harmonic ultrasound images of the gall bladder in dogs weighing greater than 16 kilograms (p = .03) and in the images of the urinary bladder of dogs weighing less than 16 kilograms (p = .02). These data suggest that image quality improvement of normal organs using tissue harmonic ultrasound is consistent but not predictable. The exception was the jejunum, where improvement was seen in all dogs. Sonographers should be cognizant of the potential benefits of tissue harmonic ultrasound.     

MAGNETIC RESONANCE IMAGING OF PULP IN NORMAL AND DISEASED EQUINE CHEEK TEETH

A retrospective analysis of 619 upper and lower cheek teeth from 62 horses was performed. Based on clinical findings, as well as radiographic and magnetic resonance (MR) imaging findings, the teeth were classified into five groups. There were 20 teeth with abnormal MR imaging signals as well as clinical alterations and 599 healthy teeth. Using MR imaging, the appearance of pulp in diseased and disease‐free teeth was compared, and the appearance of abnormal pulp was studied. Subsequently, the ability of MR imaging to diagnose pulpitis and pulp necrosis in teeth with normal external appearance was investigated. In horses with clinically verified dental disease, abnormal MR imaging findings were confirmed in the pulp of all affected teeth. An enlarged blurred pulp image with a lower signal intensity was observed only in clinically diseased teeth and was a reliable criterion for diagnosing dental disease on MR imaging. On the other hand, partial or complete absence of pulp in all MR imaging sequences was observed in both diseased and nondiseased teeth. These data demonstrate that pulp changes in equine cheek teeth can be evaluated using MR imaging.     

PLAY-DOH® AND WATER-SOAKED GAUZE SPONGES AS ALTERNATIVE BOLUS MATERIAL FOR COBALT-60 TELETHERAPY

A study was performed to determine if carefully made boluses of either Play-Doh, or water-soaked cotton gauze sponges differed from the commercial bolus material, Superflab, in producing maximum radiation dose when irradiated with cobalt-60 photons. The radiation doses were measured with thermoluminescent dosimeters calibrated to be accurate for cobalt-60 photon energies at doses less than 10.0 cGy. The resulting radiation doses were similar when using Play-Doh, water-soaked sponges, or Superlab. Doses resulting from Play-Doh boluses more consistently approximated those of Superflab. The results of this study suggest that either Play-Doh or water-soaked cotton gauze sponges can suffice as material for carefully made bolus for cobalt-60 teletherapy.     

EFFECT OF ANISOTROPY AND SPATIAL COMPOUND IMAGING ON RENAL CORTICAL ECHOGENICITY IN DOGS

The echogenicity of the renal cortex is an important parameter to consider in dogs that are suspected to have renal dysfunction. Focal increases in echogenicity have been attributed to neoplasia, infection, calcification, fibrosis, gas, and infarction. Anisotropic backscatter has been described as a source of focally increased renal cortical echogenicity in several species. The source of anisotropy appears to be the medullary rays, which are oriented perpendicular to the renal capsule. Spatial compound imaging (SCI) is an ultrasound setting that uses beam steering to acquire and average several overlapping scans of an object from different view angles, creating a compound image that is updated in real time. The impact of insonation angle and SCI on renal cortical echogenicity was evaluated ex vivo in eight kidneys from four dogs. Significant angle‐dependent differences in cortical echogenicity were detected with both microconvex and linear transducers (P < 0.0001). Furthermore, the angle‐dependent echogenicity differences persisted when SCI mode was used. Our finding that echogenicity was increased using a perpendicular insonation angle (90°) relative to the tubules, compared to a parallel insonation angle (0°) should assist in the interpretation of ultrasonographic images of the dog kidney.     

BIPLANE TRANSESOPHAGEAL ECHOCARDIOGRAPHY IN THE DOG: TECHNIQUE, ANATOMY AND IMAGING PLANES

To determine the feasibility of transesophageal echocardiography (TEE) in dogs, biplane TEE was performed in 6 normal, anesthetized dogs, using a 10 mm × 110 cm endoscopic TEE transducer. Positioning was confirmed by fluoroscopy, and imaging planes were confirmed by necropsy examination.
A transgastric position provided only a limited view of the left ventricular apex. Three TEE positions over the base of the heart were identified. A caudal position provided excellent images in both transverse and longitudinal planes, but alignment with flow for Doppler examination was poor. A middle position provided long axis views of the left ventricular inflow region and mitral valve suitable for Doppler examination. A cranial position provided excellent views for both anatomic and Doppler examination of right and left ventricular outflow and associated great vessels.
We conclude that biplane TEE provides unique views of the heart in dogs which are complementary to, and often superior to, transthoracic views for evaluation of structures at the heart base.     

COMPARISON OF SPIN ECHO, GRADIENT ECHO AND FAT SATURATION MAGNETIC RESONANCE IMAGING SEQUENCES FOR IMAGING THE CANINE ELBOW

Two comparison studies were performed. In the first conventional spin-echo (T1- and T2-weighted) sequences and a three-dimensional (3-D Fourier transform [3DFT]) echo gradient fast-imaging sequence were compared for imaging the canine normal elbow joint. In all three sequences, there was an isointense signal of the articular cartilage and a hyposignal of the subchondral bone, as compared with the muscles. The medial coronoid process of the ulna was clearly seen on the dorsal plane images, it appeared with a homogenous low-intensity signal. Its articulation with the radius was clearly outlined. In a second study, the 3DFT echo gradient fast-imaging sequence was compared to a fat saturation sequence on normal shoulder and elbow joints. Elbows were imaged with and without injection of saline, in an attmept to show the opposing cartilaginous articular surfaces. This distinction was possible in the shoulder joint but not in the elbow because of insufficient spatial resolution. On the three MRI sequences compared, gradient echo fast imaging with steady-state precession (GE FISP) sequence was found to be the most suitable for imaging the canine elbow joint.     

RADIOGRAPHIC SENSITIVITY AND NEGATIVE PREDICTIVE VALUE FOR ACUTE CANINE SPINAL TRAUMA

The objectives of this study were to establish the sensitivity and negative predictive value of radiography for acute spinal osseous lesions in the canine trauma patient, and to evaluate the interobserver variability in radiographic assessment of the spine in traumatized dogs. This was a retrospective multiple observer blinded study. The study population included 30 canine patients that presented following acute trauma, with clinical signs attributable to the spinal column. Radiography and computed tomography (CT) were performed in all cases. Radiographic interpretation was performed independently by four observers with different experience levels who were blinded to clinical information (other than trauma) and the CT results. CT studies were interpreted by a further three radiologists who formed a consensus opinion on the presence of specific osseous lesions. Using the CT results as a gold standard, the sensitivities and negative predictive values of radiography for specific osseous lesions were calculated. Interobserver agreement was also evaluated. Radiography was found to have only a moderate sensitivity for fractures (72%) and subluxations (77.5%). Low negative predictive values were found for the presence of vertebral canal narrowing (58%) and fracture fragments within the vertebral canal (51%). Interobserver agreement was only moderate to fair for most lesion types. In conclusion, radiography cannot be used to reliably rule out potentially unstable acute vertebral lesions in the canine trauma patient, and further imaging is therefore often indicated in the patient with a high risk of such injuries.