Use of radiography in small animal practice in the UK and Republic of Ireland in 2013

An Overview of Factors Affecting Exposure Level in Digital Detector Systems and their Relevance in Constructing Exposure Tables in Equine Digital Radiography

The aim of this review is to describe the steps of constructing exposure tables for use of digital detector systems (DRx) in equine practice. Introductory, selected underlying technical aspects of digital radiography are illustrated. Unlike screen-film radiography (SFR), DRx have a uniform signal response of the detector over a large dose range. This enables generation of diagnostic images from exposures that were previously nondiagnostic on SFR, thus reducing retakes. However, with decreasing detector entrance dose, image noise increasingly hampers the image quality. Conversely, unlike the blackening observed on SFR, overexposures can go visibly undetected by the observer. In DRx the numeric exposure indicator value is the only dose-control tool. In digital radiography the challenge is to reduce the dose and reduce the radiation risk to staff whilst maintaining diagnostic image quality. We provide a stepwise method of developing exposure tables as tools for controlling exposure levels. The identified kVp - mAs combinations in the table are derived from the predefined exposure indicator values of the detector system. Further recommendations are given as to how the exposure indicator can be integrated into routine workflow for rechecking the reliability of the formerly identified settings and how these tables might serve a basis for further reduction of the exposure level. Detector quantum efficiency (DQE) is an important parameter of assessing performance of an imaging system. Detectors with higher DQE can generate diagnostic images with a lower dose, thus having a greater potential for dose reduction than detectors with low DQE.

Imaging techniques in Veterinary Medicine. Part I: Radiography and Ultrasonography

In Veterinary Medicine all the Imaging techniques are used and described but, due to organizational, managerial and, mostly, economical reasons, Radiography and Ultrasonography are the most used.

Veterinary Radiology teaching has a relatively small number of educational credits in the degree courses but, nowday, educational opportunities are remarkably increased thanks to a number of post-degree courses and masters, organized both by the universities and private veterinary associations. The relevance of Diagnostic Imaging is particularly true in Veterinary Medicine, in which Radiology could be considered “indispensable” for diagnosis, prognosis and follow up. Furthermore, it should not be forgotten that the diagnostic image represents a “document” and, has a relevant role in legal medical debats.

In this first part, Radiography and Ultrasonography are described.

Imaging diagnosis of canine hip dysplasia with and without human exposure to ionizing radiation

Hip dysplasia (HD) is one of the most common hereditary orthopaedic diseases in dogs, with serious implications for the quality of life of the affected animals. Radiographic screening is essential for the selection of breeding stock in some at-risk breeds, and radiography is also used in the diagnosis of clinical HD cases. A definitive diagnosis of HD is based on radiographic examination, and the most commonly used view is the ventrodorsal hip extended projection, sometimes in combination with various hip stress-based techniques. Radiographic images require high quality positioning and dogs are usually anesthetized and often manually restrained to facilitate optimal positioning. The 'as low as reasonably achievable' (ALARA) principle used in human radioprotection is not always fulfilled in veterinary practice, except in the UK, where human exposure to ionizing radiation in veterinary medicine is strictly regulated. While each dose of ionizing radiation is small, doses accumulate over a lifetime, which can eventually result in substantial radiation exposure. Therefore, manual restraint should be avoided and mechanical immobilization, sedation or general anaesthesia should be used. This review examines the biological effects of human exposure to ionizing radiation and common sources of veterinary exposure. The diagnostic quality of imaging methods for the diagnosis of canine HD is compared between manually restrained and hands-free dog positioning. Hands-free radiographic techniques are available to assess hip laxity, degenerative joint changes and hip osseous structure while preserving image quality, and can be used to select animals for breeding or for the diagnosis of HD.

The Effects of Content Delivery Methods on Ultrasound Knobology and Image Quality Recognition Training in First-Year Veterinary Students

As new technologies are incorporated into the practice of veterinary medicine, it is imperative we utilize the most effective and impactful content delivery methods. Ultrasound technology has become more affordable and compact for veterinary hospitals, leading to easier incorporation into practice. This study compares three methods of delivering ultrasound knobology content to first-year veterinary students at Texas A&M University College of Veterinary Medicine and Biomedical Sciences. In a prospective study, first-year veterinary students were randomly selected to receive one of three content delivery methods: self-directed active learning (SDL), in-person instructor demonstration, or online module instruction. Knowledge acquisition was assessed using a 10-question quiz for short-term understanding followed by a 10-question quiz after a 6-week period to assess long-term knowledge retention. Student demographics were analyzed using the Chi-square test. Quiz scores were analyzed between groups using Kruskal-Wallis tests followed by Dunn's post-tests for multiple comparisons. Values of p ≤ .05 were considered significant. On the short-term and retention quiz questions, students participating in SDL scored significantly higher (10 [5-10]) than those receiving in-person instructor demonstration (9 [3-10] p = .01 and 8 [2-10] p = .0004, respectively) or the online module instruction training (Group C) (6 [1-10] p < 0.0001 and 8 [4-10] p < .001, respectively). Based on quiz scores, veterinary students exhibited better ultrasound knobology and image quality recognition proficiency immediately and at 6-weeks following SDL when compared with other content delivery methods. Self-directed learning methods are recommended when teaching ultrasonography to veterinary students.

Effectiveness of a digital interactive multimedia tutorial for preparing veterinary students to perform ultrasonography in horses

OBJECTIVE

To determine the effectiveness of a digital interactive multimedia tutorial (DIMT) for preparing veterinary students to perform ultrasonography in horses.

SAMPLE

42 third-year veterinary students.

PROCEDURES

Students were randomly assigned to 3 instructional methods: independent study (ie, 45 minutes to read a highlighted textbook chapter), lecture (ie, 45-minute lecture by a faculty member), or digital interactive multimedia tutorial (DIMT; ie, 45-minute narrated, interactive module). Written and practical tests were administered after each instruction session. For the practical test, each student was required to obtain a series of ultrasound images of a live horse, and images were later scored for quality by an individual unaware of the instructional method used.

RESULTS

Higher-quality ultrasound images were obtained by veterinary students who had reviewed the DIMT rather than the analogous information in textbook chapters. No difference in scores was identified between students in the lecture group and those in the DIMT group. Students' perceptions suggested that practical instruction facilitated by clinicians was a key component of learning how to perform ultrasonography in horses.

CONCLUSIONS AND CLINICAL RELEVANCE

Results supported the use of DIMTs in preparing veterinary students to perform ultrasonography in horses.

Joint laxity in canine hip dysplasia assessed using the hip flexed not distracted ventrodorsal view

OBJECTIVES

The ventrodorsal hip extended standard view is conventionally used for radiographic screening of canine hip dysplasia. However, because the ventrodorsal hip extended standard view minimises hip joint laxity, several alternative views have been proposed. Our aim was to evaluate a new ventrodorsal hip flexed and not distracted view to assess joint laxity, by comparing it with the ventrodorsal hip extended standard and ventrodorsal hip flexed and distracted views.

MATERIALS AND METHODS

Between April 2013 and March 2017, all dogs referred to the University of Naples "Federico II" for the diagnosis of canine hip dysplasia were studied using the ventrodorsal hip extended standard, ventrodorsal hip flexed and not distracted and ventrodorsal hip flexed and distracted views. The Norberg angle and the laxity index were measured for each view.

RESULTS

Overall, 102 dogs, 67 males and 35 females, mean age 15 months, were included. The mean (±standard deviation) Norberg angles were 99.77° (±10.42°), 89.29° (±14.32°) and 91.80° (±13.50°) for the ventrodorsal hip extended standard, ventrodorsal hip flexed and not distracted and ventrodorsal hip flexed and distracted views, respectively. The mean (± standard deviation) laxity indices were 0.19 (± 0.14), 0.39 (± 0.25) and 0.36 (± 0.21), respectively. The ventrodorsal hip flexed and distracted and ventrodorsal hip flexed and not distracted views had lower Norberg angle and higher laxity index values compared with the ventrodorsal hip extended standard view. The ventrodorsal hip flexed and distracted and ventrodorsal hip extended standard views are in strong agreement for the measurement of both Norberg angle and laxity index, as confirmed by Bland-Altman analysis and the intraclass correlation coefficient.

CLINICAL SIGNIFICANCE

The ventrodorsal hip flexed and distracted and ventrodorsal hip flexed and not distracted views obtained with the hip in a neutral position reveal joint laxity better than the ventrodorsal hip extended standard view. Unlike the ventrodorsal hip flexed and distracted view, the ventrodorsal hip flexed and not distracted view does not require human operators or special devices for positioning the dog. The wide age range of the dogs enrolled might have influenced the laxity index measurements, since capsular fibrosis in older dogs reduces laxity.

The left lateral projection is comparable to horizontal beam radiography for identifying experimental small volume pneumoperitoneum in the canine abdomen

Nontraumatic spontaneous pneumoperitoneum suggests the presence of gastrointestinal perforation; early detection can be lifesaving. Horizontal beam projections have been reported to be more sensitive than standard radiographic views for detecting small volumes of free peritoneal gas. This prospective, experimental, analytical study compared both left lateral (LL) and ventrodorsal (VD) standard views to horizontal beam projections for detecting small volumes of artificially induced pneumoperitoneum in live dogs. The effect of radiology training on accurate detection of small amounts of free peritoneal air was also assessed. Fourteen dogs had four radiographic projections taken after injection of 0, 2.5, 5, and 10 mL of cumulative air into their abdominal cavities. Radiographs were interpreted individually by three American College of Veterinary Radiology-certified radiologists and three small animal internship-trained veterinarians who were blinded to the air volume injected. At 2.5 and 10 mL of air injected, the LL projection had highest odds of an accurate response (odds ratio [OR] = 2.4 and 99.0 when compared to VD horizontal and VD projections, respectively). At 5 mL of air injected, the lateral horizontal (LH) projection had the highest odds of an accurate response (OR = 3.2 compared to VD horizontal). The LL projection was not significantly different from the LH projection at all volumes of air injected. Board certification led to higher odds of accurate responses at volumes of 5 (OR = 2.2) and 10 mL (OR = 3.6), as compared to nonspecialist veterinarians. Overall, LH and standard LL appeared to be the most useful radiographic projections for detection of small amounts of free peritoneal gas.