There are multiple advantages to switching to digital imaging from an analog system, and per the Textbook of Veterinary Diagnostic Radiology (Thrall, 2013) these include: decrease in cost of supplies (film, developer) and dark room maintenance (technical support); decreased number of retakes; improved latitude and contrast optimization in images (ability to evaluate both bone and soft tissue structures in the same image); ability to modify/manipulate images (window and level) after the image has been acquired; decreased storage space (hard films take up a lot of room!); improved portability (for referrals and second opinions); and increased level of professionalism with your clients in mind. Angell made this switch in 2011.
Our digital imaging services include 2 x-ray rooms and a separate fluoroscopy suite, where we are able to perform multiple basic procedures including but not limited to esophagrams and fine needle aspirates, and more advanced interventional procedures including stent placement and cardiac procedures including balloon valvuloplasty.
With the recent shift toward digital imaging from conventional film-screen systems in most veterinary hospitals, the world of teleradiology has opened up, and with this, referral cases are sent with radiographs in a variety of formats. Burned CDs, uploads via external servers such as DVM Insight (currently used at Angell), and emailed JPG images are the most common. From the radiologist’s perspective, the preferred method of sending images is either uploading the DICOM images, or burning the DICOM images to a CD. This ensures preservation of image quality as explained below.
DICOM is an acronym for “Digital Imaging and Communications in Medicine” and was established in 1993 by the American College of Radiology (ACR) and the National Electrical Manufacturers Association (NEMA). This is the file format in which medical diagnostic images are saved, and was developed to facilitate transfer of medical images and digital interfacing between multiple vendors (for example, GE and Toshiba) and modalities (such as GE ultrasound machine, Toshiba CT…). For further understanding of DICOM, please see the references listed below.
When the images that started out as DICOM are compressed and emailed as JPGs, there is a permanent elimination of file data, which remarkably reduces the size of the file. This is called “lossy” image compression and is great for eliminating redundant information. Unfortunately, sometimes there is more than redundant information removed from the radiographs that are compressed in to JPG images, which can make them difficult to evaluate. Specifically, DICOM files typically range between 4MB-12MB per image and JPG files are typically between 0.5MB-2.0MB. For clinics that have converted to digital and are sending images to a referral hospital with a patient, there are a few options.
Recently at Angell, we have tried to decrease the overall radiation dose received by our radiology technicians by encouraging primary clinicians to use light sedation when necessary/possible to help chemically restrain overactive patients, versus the more common technique of manual restraint. This has been most helpful with the orthopedic cases that require precise alignment to evaluate very small structures. As an added bonus, our radiographic studies are straighter, allowing for a better diagnostic evaluation.
> Getting the Most Out of Your Radiographs
Copple, C et al. Evaluation of two objective methods to optimize kVp and personnel exposure using a digital indirect flat panel detector and simulated veterinary patients. Vet Radiol Ultrasound 2013; 54(1):9-16.
Drost, WT, et al. Digital radiology artifacts. Vet Radiol Ultrasound 2008; 49(Supp 1):S48-S56.
Graham, RNJ, et al. DICOM demystified: A review of digital file formats and their use in radiological practice. Clinical Radiology 2005; (60);1133-40.
Robertson, ID and Thrall, DE. Digital radiographic imaging. In: Textbook of Veterinary Diagnostic Radiology; Thrall, DE, Ed. Elsevier Inc.,St. Louis, 2013, p22-37.
Widmer, WR and Thrall, DE. Radiation protection and physics of diagnostic radiology. In: Textbook of Veterinary Diagnostic Radiology; Thrall, DE, Ed. Elsevier Inc.,St. Louis, 2013, p2-21.
Wright, MA, et al. Introduction to DICOM for the practicing veterinarian. Vet Radiol Ultrasound 2008; 49(Supp 1):S14-S18.